repo stringclasses 1k
values | file_url stringlengths 96 373 | file_path stringlengths 11 294 | content stringlengths 0 32.8k | language stringclasses 1
value | license stringclasses 6
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values | retrieved_at stringdate 2026-01-04 14:45:56 2026-01-04 18:30:23 | truncated bool 2
classes |
|---|---|---|---|---|---|---|---|---|
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P102_StrShortener/src/main/java/modern/challenge/Concat.java | Chapter04/P102_StrShortener/src/main/java/modern/challenge/Concat.java | package modern.challenge;
record Concat(Str first, Str second) implements Str {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P102_StrShortener/src/main/java/modern/challenge/Main.java | Chapter04/P102_StrShortener/src/main/java/modern/challenge/Main.java | package modern.challenge;
public class Main {
/*
public static Str shortener(Str str) {
if (str instanceof Concat s) {
if (s.first() instanceof Variable first
&& s.second() instanceof Literal second && second.text().isBlank()) {
return first;
} else if (s.first() instanceof Literal first
&& s.second() instanceof Variable second && first.text().isBlank()) {
return second;
}
}
return str;
}*/
public static Str shortener(Str str) {
return switch (str) {
case Concat(Variable(var name), Literal(var text)) when text.isBlank() -> new Variable(name);
case Concat(Literal(var text), Variable(var name)) when text.isBlank() -> new Variable(name);
default -> str;
};
}
public static void main(String[] args) {
System.out.println(shortener(new Concat(new Variable("t"), new Literal(" "))));
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P102_StrShortener/src/main/java/modern/challenge/Variable.java | Chapter04/P102_StrShortener/src/main/java/modern/challenge/Variable.java | package modern.challenge;
record Variable(String name) implements Str {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/EngineType.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/EngineType.java | package modern.challenge;
public sealed abstract class EngineType permits ESSEngine, DSLEngine, LPGEngine {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/LPGEngine.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/LPGEngine.java | package modern.challenge;
public final class LPGEngine extends EngineType {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/DSLEngine.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/DSLEngine.java | package modern.challenge;
public final class DSLEngine extends EngineType {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/Car.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/Car.java | package modern.challenge;
public record Car<E extends EngineType>(E engineType) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/Main.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/Main.java | package modern.challenge;
public class Main {
public static void main(String[] args) {
Car<? extends EngineType> car1 = new Car(new DSLEngine());
Car<? extends EngineType> car2 = new Car(new ESSEngine());
Car<? extends EngineType> car3 = new Car(new LPGEngine());
System.out.println(addCarburetor1(car1));
System.out.println(addCarburetor1(car2));
System.out.println(addCarburetor1(car3));
System.out.println(addCarburetor2(car1, 1));
System.out.println(addCarburetor2(car2, 2));
System.out.println(addCarburetor2(car3, 1));
}
public static String addCarburetor1(Car c) {
return switch(c) {
// case Car(DSLEngine dsl), Car(ESSEngine ess) -> "Adding a carburetor to a ESS or DSL car";
case Car(DSLEngine _), Car(ESSEngine _) -> "Adding a carburetor to a ESS or DSL car";
case Car(LPGEngine lpg) -> "Adding a carburetor to a LPG car";
};
}
public static String addCarburetor2(Car c, int carburetorType) {
return switch(c) {
case Car(DSLEngine _), Car(ESSEngine _) when carburetorType == 1
-> "Adding a carburetor of type 1 to a ESS or DSL car";
case Car(DSLEngine _), Car(ESSEngine _)
-> "Adding a carburetor of tpye " + carburetorType + " to a ESS or DSL car";
case Car(LPGEngine lpg) -> "Adding a carburetor " + carburetorType + " to a LPG car";
};
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/ESSEngine.java | Chapter04/P103_UnnamedPatternSwitch2/src/main/java/modern/challenge/ESSEngine.java | package modern.challenge;
public final class ESSEngine extends EngineType {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P100_GenericRecords/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P100_GenericRecords/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(String type, float weight) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P100_GenericRecords/src/main/java/modern/challenge/EngineRecord.java | Chapter04/P100_GenericRecords/src/main/java/modern/challenge/EngineRecord.java | package modern.challenge;
public record EngineRecord<X, Y, Z>(X x, Y y, Z z) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P100_GenericRecords/src/main/java/modern/challenge/ContainerRecord.java | Chapter04/P100_GenericRecords/src/main/java/modern/challenge/ContainerRecord.java | package modern.challenge;
public record ContainerRecord<C>(C c) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P100_GenericRecords/src/main/java/modern/challenge/FruitRecord.java | Chapter04/P100_GenericRecords/src/main/java/modern/challenge/FruitRecord.java | package modern.challenge;
public record FruitRecord<T>(T t, String country) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P100_GenericRecords/src/main/java/modern/challenge/Main.java | Chapter04/P100_GenericRecords/src/main/java/modern/challenge/Main.java | package modern.challenge;
@SuppressWarnings("unchecked")
public class Main {
public static void main(String[] args) {
FruitRecord<MelonRecord> fruit =
new FruitRecord<>(new MelonRecord("Hami", 1000), "China");
EngineRecord<String, Integer, String> engine = new EngineRecord("TV1", 661, "Water cooled");
ContainerRecord<String> innerContainer = new ContainerRecord("Inner container");
ContainerRecord<ContainerRecord<String>> container = new ContainerRecord(innerContainer);
if (fruit instanceof FruitRecord<MelonRecord>(MelonRecord melon, String country)) {
System.out.println(melon + " from " + country);
}
if (fruit instanceof FruitRecord<MelonRecord>(var melon, var country)) {
System.out.println(melon + " from " + country);
}
if (fruit instanceof FruitRecord(var melon, var country)) {
System.out.println(melon + " from " + country);
}
if (engine instanceof EngineRecord<String, Integer, String>(var type, var power, var cooling)) {
System.out.println(type + " - " + power + " - " + cooling);
}
if (engine instanceof EngineRecord(var type, var power, var cooling)) {
System.out.println(type + " - " + power + " - " + cooling);
}
if (container instanceof ContainerRecord<ContainerRecord<String>>(ContainerRecord(var c))) {
System.out.println(c);
}
if (container instanceof ContainerRecord(ContainerRecord(var c))) {
System.out.println(c);
}
if (container instanceof ContainerRecord<ContainerRecord<String>>(var c)) {
System.out.println(c);
}
switch (fruit) {
case FruitRecord<MelonRecord>(MelonRecord melon, String country) :
System.out.println(melon + " from " + country); break;
default : break;
};
switch (fruit) {
case FruitRecord<MelonRecord>(var melon, var country) :
System.out.println(melon + " from " + country); break;
default : break;
};
switch (fruit) {
case FruitRecord(var melon, var country) :
System.out.println(melon + " from " + country); break;
default : break;
};
switch (engine) {
case EngineRecord<String, Integer, String>(var type, var power, var cooling) :
System.out.println(type + " - " + power + " - " + cooling);
default : break;
};
switch (engine) {
case EngineRecord(var type, var power, var cooling) :
System.out.println(type + " - " + power + " - " + cooling);
default : break;
};
switch (container) {
case ContainerRecord<ContainerRecord<String>>(ContainerRecord(var c)) :
System.out.println(c);
default : break;
};
switch (container) {
case ContainerRecord(ContainerRecord(var c)) :
System.out.println(c);
default : break;
};
switch (container) {
case ContainerRecord<ContainerRecord<String>>(var c) :
System.out.println(c);
default : break;
};
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/MelonMarketRecord.java | Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/MelonMarketRecord.java | package modern.challenge;
import java.util.List;
public record MelonMarketRecord(List<MelonRecord> melons, String country) {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(String type, float weight) {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/Records.java | Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/Records.java | package modern.challenge;
import java.lang.reflect.Constructor;
import java.lang.reflect.RecordComponent;
import java.util.Arrays;
public class Records {
private Records() {
throw new AssertionError("Cannot be instantiated");
}
// this method is from the official documentation of JDK
// https://docs.oracle.com/en/java/javase/19/docs/api/java.base/java/lang/Class.html#getRecordComponents()
public static <T extends Record> Constructor<T> getCanonicalConstructor(Class<T> cls)
throws NoSuchMethodException {
Class<?>[] paramTypes
= Arrays.stream(cls.getRecordComponents())
.map(RecordComponent::getType)
.toArray(Class<?>[]::new);
return cls.getDeclaredConstructor(paramTypes);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/Main.java | Chapter04/P95_RecordCanonicalCntrReflection/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
public class Main {
public static void main(String[] args)
throws NoSuchMethodException, InvocationTargetException,
InstantiationException, IllegalArgumentException, IllegalAccessException {
System.out.println(Records.getCanonicalConstructor(MelonRecord.class));
System.out.println(Records.getCanonicalConstructor(MelonMarketRecord.class));
Constructor<MelonRecord> cmr = Records.getCanonicalConstructor(MelonRecord.class);
MelonRecord m1 = cmr.newInstance("Gac", 5000f);
MelonRecord m2 = cmr.newInstance("Hemi", 1400f);
Constructor<MelonMarketRecord> cmmr = Records.getCanonicalConstructor(MelonMarketRecord.class);
MelonMarketRecord mm = cmmr.newInstance(List.of(m1, m2), "China");
System.out.println(mm);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/MainApplication.java | Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/MainApplication.java | package modern.challenge;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class MainApplication {
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/controller/BookstoreController.java | Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/controller/BookstoreController.java | package modern.challenge.controller;
import java.util.List;
import modern.challenge.service.BookstoreService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import modern.challenge.record.Author;
@RestController
public record BookstoreController(BookstoreService bookstoreService) {
@GetMapping("/authors")
public List<Author> fetchAuthors() {
return bookstoreService.fetchAuthors();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/service/BookstoreService.java | Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/service/BookstoreService.java | package modern.challenge.service;
import java.util.List;
import org.springframework.stereotype.Service;
import modern.challenge.record.Author;
import modern.challenge.record.Book;
@Service
public class BookstoreService {
public List<Author> fetchAuthors() {
List<Author> authors = List.of(
new Author("Joana Nimar", "History", List.of(
new Book("History of a day", "JN-001"),
new Book("Prague history", "JN-002")
)),
new Author("Mark Janel", "Horror", List.of(
new Book("Carrie", "MJ-001"),
new Book("House of pain", "MJ-002")
)
));
return authors;
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/record/Book.java | Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/record/Book.java | package modern.challenge.record;
public record Book(String title, String isbn) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/record/Author.java | Chapter04/P104_JavaRecordsDependencyInjection/src/main/java/modern/challenge/record/Author.java | package modern.challenge.record;
import java.util.List;
public record Author(String name, String genre, List<Book> books) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/MainApplication.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/MainApplication.java | package com.classicmodels;
import com.classicmodels.service.ClassicModelsService;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration;
import org.springframework.context.annotation.Bean;
@SpringBootApplication(exclude = {R2dbcAutoConfiguration.class})
public class MainApplication {
private final ClassicModelsService classicModelsService;
public MainApplication(ClassicModelsService classicModelsService) {
this.classicModelsService = classicModelsService;
}
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
@Bean
public ApplicationRunner init() {
return args -> {
classicModelsService.callAll();
};
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordProduct.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordProduct.java | package com.classicmodels.dto;
public record RecordProduct(String productName, String productVendor, Integer quantityInStock) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordOffice.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordOffice.java | package com.classicmodels.dto;
public record RecordOffice(String officeCode, String state, String city) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordManager.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordManager.java | package com.classicmodels.dto;
import java.util.List;
public record RecordManager(Long managerId, String managerName, List<RecordOffice> offices) {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordProductLine.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/dto/RecordProductLine.java | package com.classicmodels.dto;
import java.util.List;
public record RecordProductLine(String productLine, String textDescription, List<RecordProduct> products) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/service/ClassicModelsService.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/service/ClassicModelsService.java | package com.classicmodels.service;
import com.classicmodels.repository.ClassicModelsRepository;
import org.springframework.stereotype.Service;
@Service
public class ClassicModelsService {
private final ClassicModelsRepository classicModelsRepository;
public ClassicModelsService(ClassicModelsRepository classicModelsRepository) {
this.classicModelsRepository = classicModelsRepository;
}
public void callAll() {
classicModelsRepository.oneToMany();
classicModelsRepository.manyToMany();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/repository/ClassicModelsRepository.java | Chapter04/P106_RecordAndjOOQMultisetAgg/src/main/java/com/classicmodels/repository/ClassicModelsRepository.java | package com.classicmodels.repository;
import com.classicmodels.dto.RecordManager;
import com.classicmodels.dto.RecordOffice;
import com.classicmodels.dto.RecordProduct;
import com.classicmodels.dto.RecordProductLine;
import java.util.List;
import static jooq.generated.tables.Manager.MANAGER;
import static jooq.generated.tables.Office.OFFICE;
import static jooq.generated.tables.OfficeHasManager.OFFICE_HAS_MANAGER;
import static jooq.generated.tables.Product.PRODUCT;
import static jooq.generated.tables.Productline.PRODUCTLINE;
import org.jooq.DSLContext;
import static org.jooq.Records.mapping;
import static org.jooq.impl.DSL.field;
import static org.jooq.impl.DSL.lateral;
import static org.jooq.impl.DSL.multisetAgg;
import static org.jooq.impl.DSL.name;
import static org.jooq.impl.DSL.select;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
@Transactional(readOnly = true)
public class ClassicModelsRepository {
private final DSLContext ctx;
public ClassicModelsRepository(DSLContext ctx) {
this.ctx = ctx;
}
public void oneToMany() {
List<RecordProductLine> resultRecord = ctx.select(
PRODUCTLINE.PRODUCT_LINE, PRODUCTLINE.TEXT_DESCRIPTION,
multisetAgg(PRODUCT.PRODUCT_NAME, PRODUCT.PRODUCT_VENDOR,
PRODUCT.QUANTITY_IN_STOCK)
.as("products").convertFrom(r -> r.map(mapping(RecordProduct::new))))
.from(PRODUCTLINE)
.join(PRODUCT)
.on(PRODUCTLINE.PRODUCT_LINE.eq(PRODUCT.PRODUCT_LINE))
.groupBy(PRODUCTLINE.PRODUCT_LINE, PRODUCTLINE.TEXT_DESCRIPTION)
.orderBy(PRODUCTLINE.PRODUCT_LINE)
.fetch(mapping(RecordProductLine::new));
System.out.println("One-to-many (Record):\n" + resultRecord);
}
public void manyToMany() {
List<RecordManager> resultRecord = ctx.select(
MANAGER.MANAGER_ID, MANAGER.MANAGER_NAME,
multisetAgg(
field(name("t", "officeCode"), String.class),
field(name("t", "city"), String.class),
field(name("t", "state"), String.class))
.as("offices").convertFrom(r -> r.map(mapping(RecordOffice::new))))
.from(MANAGER, lateral(select(OFFICE.OFFICE_CODE.as("officeCode"),
OFFICE.CITY.as("city"), OFFICE.STATE.as("state"))
.from(OFFICE).join(OFFICE_HAS_MANAGER)
.on(OFFICE.OFFICE_CODE.eq(OFFICE_HAS_MANAGER.OFFICES_OFFICE_CODE))
.where(MANAGER.MANAGER_ID.eq(OFFICE_HAS_MANAGER.MANAGERS_MANAGER_ID))).asTable("t"))
.groupBy(MANAGER.MANAGER_ID)
.orderBy(MANAGER.MANAGER_ID)
.fetch(mapping(RecordManager::new));
System.out.println("Many-to-many (Record):\n" + resultRecord);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(SeedRecord seed, float weight) implements Fruit {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/Fruit.java | Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/Fruit.java | package modern.challenge;
public interface Fruit {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/SeedRecord.java | Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/SeedRecord.java | package modern.challenge;
public record SeedRecord(String type, String country) implements Fruit {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/EggplantRecord.java | Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/EggplantRecord.java | package modern.challenge;
public record EggplantRecord(SeedRecord seed, float weight) implements Fruit {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/Main.java | Chapter04/P101_UnconditionalPatternRecords/src/main/java/modern/challenge/Main.java | package modern.challenge;
public class Main {
public static String buyFruit1(Fruit fruit) {
return switch(fruit) {
case null -> "Ops!";
case SeedRecord(String type, String country) -> "This is a seed of " + type + " from " + country;
case EggplantRecord(SeedRecord seed, float weight) when seed == null -> "Ops! What's this?!";
case EggplantRecord(SeedRecord seed, float weight) -> "This is a " + seed.type() + " eggplant";
// case EggplantRecord(null, float weight) -> "Ops! What's this?!"; // DOESN'T COMPILE
case MelonRecord(SeedRecord seed, float weight) -> "This is a " + seed.type() + " melon";
// case MelonRecord(null, float weight) -> "Ops! What's this?!"; // DOESN'T COMPILE
case Fruit v -> "This is an unknown fruit";
};
}
public static String buyFruit2(Fruit fruit) {
if (fruit instanceof SeedRecord(String type, String country)) {
return "This is a seed of " + type + " from " + country;
}
if (fruit instanceof EggplantRecord(SeedRecord seed, float weight) && seed == null) {
return "Ops! What's this?!";
}
if (fruit instanceof EggplantRecord(SeedRecord seed, float weight)) {
return "This is a " + seed.type() + " eggplant";
}
/* // DOESN'T COMPILE
if (fruit instanceof EggplantRecord(null, float weight)) {
return "Ops! What's this?!";
}
*/
if (fruit instanceof MelonRecord(SeedRecord seed, float weight)) {
return "This is a " + seed.type() + " melon";
}
/* // DOESN'T COMPILE
if (fruit instanceof MelonRecord(null, float weight)) {
return "Ops! What's this?!";
}
*/
return "This is an unknown fruit";
}
public static void main(String[] args) {
SeedRecord seed = new SeedRecord("Fairytale", "India");
EggplantRecord eggplant = new EggplantRecord(seed, 300);
EggplantRecord badEggplant = new EggplantRecord(null, 300);
System.out.println(buyFruit1(null)); // Ops
System.out.println(buyFruit1(seed)); // This is a seed of Fairytale from India
System.out.println(buyFruit1(eggplant)); // This is a Fairytale eggplant
System.out.println(buyFruit1(badEggplant)); // Ops! What's this?!
System.out.println();
System.out.println(buyFruit2(null)); // This is an unknown fruit
System.out.println(buyFruit2(seed)); // This is a seed of Fairytale from India
System.out.println(buyFruit2(eggplant)); // This is a Fairytale eggplant
System.out.println(buyFruit2(badEggplant)); // Ops! What's this?!
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/MainApplication.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/MainApplication.java | package com.bookstore;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import com.bookstore.service.BookstoreService;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
public class MainApplication {
private final BookstoreService bookstoreService;
public MainApplication(BookstoreService bookstoreService) {
this.bookstoreService = bookstoreService;
}
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
@Bean
public ApplicationRunner init() {
return args -> {
List<AuthorDto> authors = bookstoreService.fetchAuthorWithBook();
System.out.println("Number of authors:" + authors.size());
authors.forEach(a -> System.out.println("\n" + a));
};
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dto/AuthorDto.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dto/AuthorDto.java | package com.bookstore.dto;
import java.util.List;
public record AuthorDto(Long id, String name, int age, List<BookDto> books) {
public void addBook(BookDto book) {
books().add(book);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dto/BookDto.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dto/BookDto.java | package com.bookstore.dto;
public record BookDto(Long id, String title) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dao/Dao.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dao/Dao.java | package com.bookstore.dao;
import com.bookstore.dto.AuthorDto;
import com.bookstore.transformer.AuthorBookTransformer;
import jakarta.persistence.EntityManager;
import jakarta.persistence.PersistenceContext;
import jakarta.persistence.Query;
import java.util.List;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
public class Dao implements AuthorDao {
@PersistenceContext
private EntityManager entityManager;
@Override
@Transactional(readOnly = true)
public List<AuthorDto> fetchAuthorWithBook() {
AuthorBookTransformer abt = new AuthorBookTransformer();
Query query = entityManager
.createNativeQuery(
"SELECT a.id AS author_id, a.name AS name, a.age AS age, "
+ "b.id AS book_id, b.title AS title "
+ "FROM author a JOIN book b ON a.id=b.author_id")
.unwrap(org.hibernate.query.NativeQuery.class)
.setTupleTransformer(abt)
.setResultListTransformer(abt);
List<AuthorDto> authors = query.getResultList();
return authors;
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dao/AuthorDao.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/dao/AuthorDao.java | package com.bookstore.dao;
import java.util.List;
import com.bookstore.dto.AuthorDto;
public interface AuthorDao {
public List<AuthorDto> fetchAuthorWithBook();
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/service/BookstoreService.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/service/BookstoreService.java | package com.bookstore.service;
import com.bookstore.dao.Dao;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import org.springframework.stereotype.Service;
@Service
public record BookstoreService(Dao dao) {
public List<AuthorDto> fetchAuthorWithBook() {
List<AuthorDto> authors = dao.fetchAuthorWithBook();
return authors;
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/entity/Book.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/entity/Book.java | package com.bookstore.entity;
import jakarta.persistence.Entity;
import jakarta.persistence.FetchType;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.ManyToOne;
import java.io.Serializable;
@Entity
public class Book implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String title;
private String isbn;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "author_id")
private Author author;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getIsbn() {
return isbn;
}
public void setIsbn(String isbn) {
this.isbn = isbn;
}
public Author getAuthor() {
return author;
}
public void setAuthor(Author author) {
this.author = author;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
return id != null && id.equals(((Book) obj).id);
}
@Override
public int hashCode() {
return 2021;
}
@Override
public String toString() {
return "Book{" + "id=" + id + ", title=" + title + ", isbn=" + isbn + '}';
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/entity/Author.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/entity/Author.java | package com.bookstore.entity;
import jakarta.persistence.CascadeType;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.OneToMany;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
@Entity
public class Author implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
private String genre;
private int age;
@OneToMany(cascade = CascadeType.ALL,
mappedBy = "author", orphanRemoval = true)
private List<Book> books = new ArrayList<>();
public void addBook(Book book) {
this.books.add(book);
book.setAuthor(this);
}
public void removeBook(Book book) {
book.setAuthor(null);
this.books.remove(book);
}
public void removeBooks() {
Iterator<Book> iterator = this.books.iterator();
while (iterator.hasNext()) {
Book book = iterator.next();
book.setAuthor(null);
iterator.remove();
}
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGenre() {
return genre;
}
public void setGenre(String genre) {
this.genre = genre;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public List<Book> getBooks() {
return books;
}
public void setBooks(List<Book> books) {
this.books = books;
}
@Override
public String toString() {
return "Author{" + "id=" + id + ", name=" + name
+ ", genre=" + genre + ", age=" + age + '}';
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/transformer/AuthorBookTransformer.java | Chapter04/P105_DtoRecordResultTransformer/src/main/java/com/bookstore/transformer/AuthorBookTransformer.java | package com.bookstore.transformer;
import com.bookstore.dto.AuthorDto;
import com.bookstore.dto.BookDto;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.hibernate.query.ResultListTransformer;
import org.hibernate.query.TupleTransformer;
public class AuthorBookTransformer implements TupleTransformer, ResultListTransformer {
private final Map<Long, AuthorDto> authorsDtoMap = new HashMap<>();
@Override
public Object transformTuple(Object[] os, String[] strings) {
Long authorId = ((Number) os[0]).longValue();
AuthorDto authorDto = authorsDtoMap.get(authorId);
if (authorDto == null) {
authorDto = new AuthorDto(((Number) os[0]).longValue(), (String) os[1], (int) os[2], new ArrayList<>());
}
BookDto bookDto = new BookDto(((Number) os[3]).longValue(), (String) os[4]);
authorDto.addBook(bookDto);
authorsDtoMap.putIfAbsent(authorDto.id(), authorDto);
return authorDto;
}
@Override
public List<AuthorDto> transformList(List list) {
return new ArrayList<>(authorsDtoMap.values());
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P90_EnrichedRecord/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P90_EnrichedRecord/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(String type, float weight) {
private static final String DEFAULT_MELON_TYPE = "Crenshaw";
private static final float DEFAULT_MELON_WEIGHT = 1000;
public float weightToKg() {
return weight / 1_000;
}
public static MelonRecord getDefaultMelon() {
return new MelonRecord(DEFAULT_MELON_TYPE, DEFAULT_MELON_WEIGHT);
}
public static class Slicer {
public void slice(MelonRecord mr, int n) {
start();
System.out.println("Slicing a " + mr.type() + " of "
+ mr.weightToKg() + " kg in " + n + " slices ...");
stop();
}
private static void start() {
System.out.println("Start slicer ...");
}
private static void stop() {
System.out.println("Stop slicer ...");
}
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P90_EnrichedRecord/src/main/java/modern/challenge/Main.java | Chapter04/P90_EnrichedRecord/src/main/java/modern/challenge/Main.java | package modern.challenge;
public class Main {
public static void main(String[] args) {
MelonRecord melon = new MelonRecord("Cantaloupe", 2600);
System.out.println(melon);
System.out.println(melon.weight() + " g = " + melon.weightToKg() + " Kg");
System.out.println();
MelonRecord defaultMelon = MelonRecord.getDefaultMelon();
System.out.println(defaultMelon);
System.out.println();
MelonRecord.Slicer slicer= new MelonRecord.Slicer();
slicer.slice(melon, 10);
slicer.slice(defaultMelon, 14);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnamedVariables/src/main/java/modern/challenge/Melon.java | Chapter04/P103_UnamedVariables/src/main/java/modern/challenge/Melon.java | package modern.challenge;
import java.util.Objects;
public class Melon {
private final String type;
private final int weight;
public Melon(String type, int weight) {
this.type = type;
this.weight = weight;
}
public String getType() {
return type;
}
public int getWeight() {
return weight;
}
@Override
public int hashCode() {
int hash = 7;
hash = 47 * hash + Objects.hashCode(this.type);
hash = 47 * hash + this.weight;
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final Melon other = (Melon) obj;
if (this.weight != other.weight) {
return false;
}
if (!Objects.equals(this.type, other.type)) {
return false;
}
return true;
}
@Override
public String toString() {
return type + "(" + weight + "g)";
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnamedVariables/src/main/java/modern/challenge/Main.java | Chapter04/P103_UnamedVariables/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.io.IOException;
import java.lang.foreign.Arena;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
public class Main {
public static void main(String[] args) throws IOException {
// in a catch block
int divisor = 0;
try {
int result = 1 / divisor;
// use result
} catch (ArithmeticException _) {
System.out.println("Divisor " + divisor + " is not good");
}
// in a simple for loop
int[] arr = new int[]{1, 2, 3};
for (int i = 0, _ = logLoopStart(i); i < arr.length; i++) {
// use i
}
// in an enhanced for loop
int score = 0;
List<String> cards = List.of("12 spade", "6 diamond", "14 diamond");
for (String _ : cards) {
if (score < 10) {
score ++;
} else {
score --;
}
}
// in an assignment that ignores the result
boolean _ = Files.deleteIfExists(Path.of("/file.txt"));
// var _ = Files.deleteIfExists(Path.of("/file.txt"));
// in try-with-resources
try (Arena _ = Arena.ofConfined()) {
// don't use arena
}
// in lambda expressions
List<Melon> melons = Arrays.asList(new Melon("Crenshaw", 2000),
new Melon("Hemi", 1600), new Melon("Gac", 3000),
new Melon("Apollo", 2000), new Melon("Horned", 1700),
new Melon("Gac", 3000), new Melon("Cantaloupe", 2600)
);
Map<String, Integer> resultToMap = melons.stream()
.collect(Collectors.toMap(Melon::getType, Melon::getWeight,
(oldValue, _) -> oldValue));
}
private static int logLoopStart(int i) {
System.out.println("Loop started ...");
return i;
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Hospital.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Hospital.java | package modern.challenge;
import java.time.LocalDate;
public final class Hospital {
private Hospital() {
throw new AssertionError("Cannot be instantiated");
}
public static String cabinet(Staff staff) {
/*
if (staff instanceof Doctor(String name, String specialty)) {
return "The cabinet of " + specialty + " is currently under renovation";
}
*/
if (staff instanceof Doctor(_, String specialty)) { // if (staff instanceof Doctor(var _, String specialty))
return "The cabinet of " + specialty + " is currently under renovation";
}
/*
if (staff instanceof Resident(String name, Doctor dr)) {
return "The resident of this cabinet is : " + name;
}
*/
if (staff instanceof Resident(String name, _)) {
return "The resident of this cabinet is : " + name;
}
if (staff instanceof Resident(String rsname, Doctor(String drname, _))) {
return "This is the cabinet of doctor " + drname + " and resident " + rsname;
}
return "Cabinet closed";
}
public static String reception(Object o) {
/*
if (o instanceof Patient(var ptname, var npi,
Appointment(var date,
Doctor (var drname, var specialty)))) {
return "Patient " + ptname + " has an appointment for the date of " + date;
}
*/
if (o instanceof Patient(var ptname, _, Appointment(var date, _))) {
return "Patient " + ptname + " has an appointment for the date of " + date;
}
/*
if (o instanceof Patient(var ptname, var npi,
Appointment(var date,
Doctor (var drname, var specialty)))) {
return "Patient " + ptname + " has an appointment";
}
*/
if (o instanceof Patient(var ptname, _, _)) {
return "Patient " + ptname + " has an appointment";
}
/*
if (o instanceof Patient pt) {
return "Patient " + pt.name() + " has an appointment";
}
*/
return "";
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Patient.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Patient.java | package modern.challenge;
public record Patient(String name, int npi, Appointment appointment) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Resident.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Resident.java | package modern.challenge;
public record Resident(String name, Doctor doctor) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Staff.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Staff.java | package modern.challenge;
public interface Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Appointment.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Appointment.java | package modern.challenge;
import java.time.LocalDate;
public record Appointment(LocalDate date, Doctor doctor) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Doctor.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Doctor.java | package modern.challenge;
public record Doctor(String name, String specialty) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Main.java | Chapter04/P103_UnnamedPatternsInstanceof/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.time.LocalDate;
public class Main {
public static void main(String[] args) {
Doctor dr = new Doctor("John Beer", "Dermatology");
Resident rs = new Resident("Mark Oil", dr);
Patient pt = new Patient("Alicia Goy", 1234567890,
new Appointment(LocalDate.now(),
new Doctor("Rares Masdd", "Rheumatology")));
System.out.println(Hospital.cabinet(dr));
System.out.println(Hospital.cabinet(rs));
System.out.println(Hospital.reception(pt));
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Hospital.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Hospital.java | package modern.challenge;
public final class Hospital {
private Hospital() {
throw new AssertionError("Cannot be instantiated");
}
/*
public static String cabinet(Staff staff) {
if (staff instanceof Doctor) {
Doctor dr = (Doctor) staff;
return "Cabinet of " + dr.specialty() + ". Doctor: " + dr.name();
}
if (staff instanceof Resident) {
Resident rs = (Resident) staff;
return "Cabinet of " + rs.doctor().specialty() + ". Doctor: "
+ rs.doctor().name() + ", Resident: " + rs.name();
}
return "Cabinet closed";
}
*/
public static String cabinet(Staff staff) {
/*
if (staff instanceof Doctor dr) { // type pattern matching
return "Cabinet of " + dr.specialty() + ". Doctor: " + dr.name();
}
*/
if (staff instanceof Doctor(String name, String specialty)) { // record pattern matching
return "Cabinet of " + name + ". Doctor: " + specialty;
}
/*
if (staff instanceof Resident rs) { // type pattern matching
return "Cabinet of " + rs.doctor().specialty() + ". Doctor: "
+ rs.doctor().name() + ", Resident: " + rs.name();
}
*/
/*
if (staff instanceof Resident(String name, Doctor dr)) { // record pattern matching
return "Cabinet of " + dr.specialty() + ". Doctor: "
+ dr.name() + ", Resident: " + name;
}
*/
if (staff instanceof Resident(String rsname,
Doctor(String drname, String specialty))) { // record pattern matching
return "Cabinet of " + specialty + ". Doctor: "
+ drname + ", Resident: " + rsname;
}
return "Cabinet closed";
}
public static String reception(Object o) {
/*
if (o instanceof Patient(String ptname, int npi,
Appointment(LocalDate date,
Doctor (String drname, String specialty)))) {
return "Patient " + ptname + " (NPI: " + npi + ") has an appointment at "
+ date + " to the doctor " + drname + " (" + specialty + ").";
}
*/
/*
if (o instanceof Patient(var ptname, var npi, var ap)) {
return "Patient " + ptname + " (NPI: " + npi + ") has an appointment at "
+ ap.date() + " to the doctor " + ap.doctor().name() + " (" + ap.doctor().specialty() + ").";
}
*/
if (o instanceof Patient(var ptname, var npi,
Appointment(var date,
Doctor (var drname, var specialty)))) {
return "Patient " + ptname + " (NPI: " + npi + ") has an appointment at "
+ date + " to the doctor " + drname + " (" + specialty + ").";
}
return "";
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Patient.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Patient.java | package modern.challenge;
public record Patient(String name, int npi, Appointment appointment) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Resident.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Resident.java | package modern.challenge;
public record Resident(String name, Doctor doctor) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Staff.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Staff.java | package modern.challenge;
public interface Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Appointment.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Appointment.java | package modern.challenge;
import java.time.LocalDate;
public record Appointment(LocalDate date, Doctor doctor) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Doctor.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Doctor.java | package modern.challenge;
public record Doctor(String name, String specialty) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Main.java | Chapter04/P97_RecordPatternInstanceof/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.time.LocalDate;
public class Main {
public static void main(String[] args) {
Doctor dr = new Doctor("John Beer", "Dermatology");
Resident rs = new Resident("Mark Oil", dr);
Patient pt = new Patient("Alicia Goy", 1234567890,
new Appointment(LocalDate.now(),
new Doctor("Rares Masdd", "Rheumatology")));
System.out.println(Hospital.cabinet(dr));
System.out.println(Hospital.cabinet(rs));
System.out.println(Hospital.reception(pt));
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
import java.io.Serializable;
import java.util.Objects;
public record MelonRecord(String type, float weight) implements Serializable {
public MelonRecord {
Objects.requireNonNull(type, "The melon's type cannot be null");
if (weight < 1000 || weight > 10000) {
throw new IllegalArgumentException(
"The melon's weight must be between 1000 and 10000 grams");
}
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/Melon.java | Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/Melon.java | package modern.challenge;
import java.io.Serializable;
import java.util.Objects;
public class Melon implements Serializable {
private final String type;
private final float weight;
public Melon(String type, float weight) {
Objects.requireNonNull(type, "The melon's type cannot be null");
if (weight < 1000 || weight > 10000) {
throw new IllegalArgumentException(
"The melon's weight must be between 1000 and 10000 grams");
}
this.type = type;
this.weight = weight;
}
public String getType() {
return type;
}
public float getWeight() {
return weight;
}
@Override
public int hashCode() {
int hash = 3;
hash = 89 * hash + Objects.hashCode(this.type);
hash = 89 * hash + Float.floatToIntBits(this.weight);
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final Melon other = (Melon) obj;
if (this.weight != other.weight) {
return false;
}
if (!Objects.equals(this.type, other.type)) {
return false;
}
return true;
}
@Override
public String toString() {
return "Melon{" + "type=" + type + ", weight=" + weight + '}';
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonContainer.java | Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonContainer.java | package modern.challenge;
import java.io.ObjectStreamException;
import java.io.Serial;
import java.io.Serializable;
import java.time.LocalDate;
import java.util.Objects;
public class MelonContainer implements Serializable {
private final LocalDate expiration;
private final String batch;
private final Melon melon;
public MelonContainer(LocalDate expiration, String batch, Melon melon) {
Objects.requireNonNull(expiration, "The expiration date cannot be null");
Objects.requireNonNull(batch, "The batch cannot be null");
Objects.requireNonNull(melon, "The melon cannot be null");
if (!batch.startsWith("ML")) {
throw new IllegalArgumentException("The batch format should be: MLxxxxxxxx");
}
if (expiration.isBefore(LocalDate.now())) {
throw new IllegalArgumentException("The expiration date cannot be before the current date");
}
this.expiration = expiration;
this.batch = batch;
this.melon = melon;
}
public LocalDate getExpiration() {
return expiration;
}
public String getBatch() {
return batch;
}
public Melon getMelon() {
return melon;
}
@Serial
private Object writeReplace() throws ObjectStreamException {
System.out.println("Serialization is done via writeReplace() ...");
return new MelonContainerRecord(expiration, batch, melon);
}
@Override
public int hashCode() {
int hash = 7;
hash = 97 * hash + Objects.hashCode(this.expiration);
hash = 97 * hash + Objects.hashCode(this.batch);
hash = 97 * hash + Objects.hashCode(this.melon);
return hash;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
final MelonContainer other = (MelonContainer) obj;
if (!Objects.equals(this.batch, other.batch)) {
return false;
}
if (!Objects.equals(this.expiration, other.expiration)) {
return false;
}
return Objects.equals(this.melon, other.melon);
}
@Override
public String toString() {
return "MelonContainer{" + "expiration=" + expiration
+ ", batch=" + batch + ", melon=" + melon + '}';
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/Main.java | Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.time.LocalDate;
public class Main {
public static void main(String[] args) throws IOException, ClassNotFoundException {
MelonContainer gacContainer = new MelonContainer(
LocalDate.now().plusDays(15), "ML9000SQA0", new Melon("Gac", 5000)
);
try ( ObjectOutputStream oos = new ObjectOutputStream(
new FileOutputStream("object.data"))) {
oos.writeObject(gacContainer);
}
MelonContainer desGacContainer;
try ( ObjectInputStream ios = new ObjectInputStream(
new FileInputStream("object.data"))) {
desGacContainer = (MelonContainer) ios.readObject();
}
System.out.println(desGacContainer);
MelonContainer maliciousDesGacContainer;
try ( ObjectInputStream ios = new ObjectInputStream(
new FileInputStream("object_malicious.data"))) {
maliciousDesGacContainer = (MelonContainer) ios.readObject();
}
System.out.println(maliciousDesGacContainer);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonContainerRecord.java | Chapter04/P94_RefactoringSerialization/src/main/java/modern/challenge/MelonContainerRecord.java | package modern.challenge;
import java.io.ObjectStreamException;
import java.io.Serial;
import java.io.Serializable;
import java.time.LocalDate;
import java.util.Objects;
public record MelonContainerRecord(LocalDate expiration, String batch, Melon melon) implements Serializable {
public MelonContainerRecord {
Objects.requireNonNull(expiration, "The expiration date cannot be null");
Objects.requireNonNull(batch, "The batch cannot be null");
Objects.requireNonNull(melon, "The melon cannot be null");
if (!batch.startsWith("ML")) {
throw new IllegalArgumentException("The batch format should be: MLxxxxxxxx");
}
if (expiration.isBefore(LocalDate.now())) {
throw new IllegalArgumentException("The expiration date cannot be before the current date");
}
}
@Serial
private Object readResolve() throws ObjectStreamException {
System.out.println("Deserialization is done via readResolve() ...");
return new MelonContainer(expiration, batch, melon);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Hospital.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Hospital.java | package modern.challenge;
import java.time.LocalDate;
public final class Hospital {
private Hospital() {
throw new AssertionError("Cannot be instantiated");
}
public static String cabinet(Staff staff) {
return switch(staff) {
//case Doctor dr
// when dr.speciality().equals("Dermatology")
// -> "The cabinet of " + dr.speciality() + " is currently under renovation";
case Doctor(var name, var speciality)
when speciality.equals("Dermatology")
-> "The cabinet of " + speciality + " is currently under renovation";
case Doctor(var name, var speciality)
when (speciality.equals("Allergy") && (name.equals("Kyle Ulm")))
-> "The cabinet of " + speciality + " is closed. The doctor " + name + " is on holiday.";
case Doctor(var name, var speciality)
when (speciality.equals("Allergy") && (name.equals("John Hora")))
-> "The cabinet of " + speciality + " is open. The doctor " + name + " is ready to receive patients.";
case Resident(var rsname, Doctor(var drname, var speciality))
when (speciality.equals("Dermatology") && rsname.equals("Mark Oil"))
-> "Cabinet of " + speciality + ". Doctor " + drname + " and resident " + rsname + " are ready to receive patients.";
default -> "Cabinet closed";
};
}
public static String reception(Object o) {
return switch(o) {
case Patient(String ptname, int npi,
Appointment(LocalDate date,
Doctor (String drname, String speciality)))
when (ptname.equals("Alicia Goy") && npi == 1234567890 && LocalDate.now().equals(date))
-> "The doctor " + drname + " from " + speciality + " is ready for you " + ptname;
default -> "";
};
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Patient.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Patient.java | package modern.challenge;
public record Patient(String name, int npi, Appointment appointment) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Resident.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Resident.java | package modern.challenge;
public record Resident(String name, Doctor doctor) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Staff.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Staff.java | package modern.challenge;
public interface Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Appointment.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Appointment.java | package modern.challenge;
import java.time.LocalDate;
public record Appointment(LocalDate date, Doctor doctor) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Doctor.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Doctor.java | package modern.challenge;
public record Doctor(String name, String specialty) implements Staff {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Main.java | Chapter04/P99_RecordPatternSwitchGuarded/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.time.LocalDate;
public class Main {
public static void main(String[] args) {
Doctor dr1 = new Doctor("John Beer", "Dermatology");
Doctor dr2 = new Doctor("Kyle Ulm", "Allergy");
Doctor dr3 = new Doctor("John Hora", "Allergy");
Resident rs = new Resident("Mark Oil", dr1);
Patient pt = new Patient("Alicia Goy", 1234567890,
new Appointment(LocalDate.now(),
new Doctor("Rares Masdd", "Rheumatology")));
System.out.println(Hospital.cabinet(dr1));
System.out.println(Hospital.cabinet(dr2));
System.out.println(Hospital.cabinet(dr3));
System.out.println(Hospital.cabinet(rs));
System.out.println(Hospital.reception(pt));
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/MainApplication.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/MainApplication.java | package com.classicmodels;
import com.classicmodels.service.ClassicModelsService;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.r2dbc.R2dbcAutoConfiguration;
import org.springframework.context.annotation.Bean;
@SpringBootApplication(exclude = {R2dbcAutoConfiguration.class})
public class MainApplication {
private final ClassicModelsService classicModelsService;
public MainApplication(ClassicModelsService classicModelsService) {
this.classicModelsService = classicModelsService;
}
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
@Bean
public ApplicationRunner init() {
return args -> {
classicModelsService.callAll();
};
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordProduct.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordProduct.java | package com.classicmodels.dto;
public record RecordProduct(String productName, String productVendor, Integer quantityInStock) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordOffice.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordOffice.java | package com.classicmodels.dto;
public record RecordOffice(String officeCode, String state, String city) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordManager.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordManager.java | package com.classicmodels.dto;
import java.util.List;
public record RecordManager(Long managerId, String managerName, List<RecordOffice> offices) {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordProductLine.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/dto/RecordProductLine.java | package com.classicmodels.dto;
import java.util.List;
public record RecordProductLine(String productLine, String textDescription, List<RecordProduct> products) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/service/ClassicModelsService.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/service/ClassicModelsService.java | package com.classicmodels.service;
import com.classicmodels.repository.ClassicModelsRepository;
import org.springframework.stereotype.Service;
@Service
public class ClassicModelsService {
private final ClassicModelsRepository classicModelsRepository;
public ClassicModelsService(ClassicModelsRepository classicModelsRepository) {
this.classicModelsRepository = classicModelsRepository;
}
public void callAll() {
classicModelsRepository.oneToMany();
classicModelsRepository.manyToMany();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/repository/ClassicModelsRepository.java | Chapter04/P106_RecordAndjOOQMultiset/src/main/java/com/classicmodels/repository/ClassicModelsRepository.java | package com.classicmodels.repository;
import com.classicmodels.dto.RecordManager;
import com.classicmodels.dto.RecordOffice;
import com.classicmodels.dto.RecordProduct;
import com.classicmodels.dto.RecordProductLine;
import java.util.List;
import static jooq.generated.tables.Manager.MANAGER;
import static jooq.generated.tables.Office.OFFICE;
import static jooq.generated.tables.OfficeHasManager.OFFICE_HAS_MANAGER;
import static jooq.generated.tables.Product.PRODUCT;
import static jooq.generated.tables.Productline.PRODUCTLINE;
import org.jooq.DSLContext;
import static org.jooq.Records.mapping;
import static org.jooq.impl.DSL.multiset;
import static org.jooq.impl.DSL.select;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
@Transactional(readOnly = true)
public class ClassicModelsRepository {
private final DSLContext ctx;
public ClassicModelsRepository(DSLContext ctx) {
this.ctx = ctx;
}
public void oneToMany() {
List<RecordProductLine> resultRecord = ctx.select(
PRODUCTLINE.PRODUCT_LINE, PRODUCTLINE.TEXT_DESCRIPTION,
multiset(
select( // or selectDistinct() if you are in a case with duplicates
PRODUCT.PRODUCT_NAME, PRODUCT.PRODUCT_VENDOR, PRODUCT.QUANTITY_IN_STOCK)
.from(PRODUCT)
.where(PRODUCTLINE.PRODUCT_LINE.eq(PRODUCT.PRODUCT_LINE))
).as("products").convertFrom(r -> r.map(mapping(RecordProduct::new))))
.from(PRODUCTLINE)
.orderBy(PRODUCTLINE.PRODUCT_LINE)
.fetch(mapping(RecordProductLine::new));
System.out.println("One-to-many (Record):\n" + resultRecord);
}
public void manyToMany() {
List<RecordManager> resultRecord = ctx.select(
MANAGER.MANAGER_ID, MANAGER.MANAGER_NAME,
multiset(
select(
OFFICE.OFFICE_CODE, OFFICE.CITY, OFFICE.STATE)
.from(OFFICE)
.join(OFFICE_HAS_MANAGER)
.on(OFFICE.OFFICE_CODE.eq(OFFICE_HAS_MANAGER.OFFICES_OFFICE_CODE))
.where(MANAGER.MANAGER_ID.eq(OFFICE_HAS_MANAGER.MANAGERS_MANAGER_ID))
).as("offices").convertFrom(r -> r.map(mapping(RecordOffice::new))))
.from(MANAGER)
.orderBy(MANAGER.MANAGER_ID)
.fetch(mapping(RecordManager::new));
System.out.println("Many-to-many (Record):\n" + resultRecord);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(String type, float weight) {} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/WeightsAndTotalRecord.java | Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/WeightsAndTotalRecord.java | package modern.challenge;
import java.util.List;
public record WeightsAndTotalRecord(double totalWeight, List<Float> weights) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/Main.java | Chapter04/P96_UsingRecordsInStreams/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
import static java.util.stream.Collectors.counting;
import static java.util.stream.Collectors.mapping;
import static java.util.stream.Collectors.summingDouble;
import static java.util.stream.Collectors.toList;
import java.util.stream.DoubleStream;
public class Main {
public static void main(String[] args) {
// EXAMPLE 1
List<MelonRecord> melons = Arrays.asList(new MelonRecord("Crenshaw", 1200),
new MelonRecord("Gac", 3000), new MelonRecord("Hemi", 2600),
new MelonRecord("Hemi", 1600), new MelonRecord("Gac", 1200),
new MelonRecord("Apollo", 2600), new MelonRecord("Horned", 1700),
new MelonRecord("Gac", 3000), new MelonRecord("Hemi", 2600)
);
WeightsAndTotalRecord weightsAndTotal = melons.stream()
.collect(Collectors.teeing(
summingDouble(MelonRecord::weight),
mapping(MelonRecord::weight, toList()),
WeightsAndTotalRecord::new
));
System.out.println(weightsAndTotal);
// EXAMPLE 2
/*
Map<Double, Long> elevations = DoubleStream.of(22, -10, 100, -5, 100, 123, 22, 230, -1, 250, 22)
.filter(e -> e > 0)
.map(e -> e * 0.393701)
.mapToObj(e -> (double) e)
.collect(Collectors.groupingBy(Function.identity(), counting()));
*/
record Elevation(double value) { Elevation(double value) { this.value = value * 0.393701; } }
record ElevationCount(long count) {}
Map<Elevation, ElevationCount> elevations = DoubleStream.of(22, -10, 100, -5, 100, 123, 22, 230, -1, 250, 22)
.filter(e -> e > 0)
.mapToObj(Elevation::new)
.collect(Collectors.groupingBy(Function.identity(),
Collectors.collectingAndThen(counting(), ElevationCount::new)));
System.out.println(elevations);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/MainApplication.java | Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/MainApplication.java | package com.bookstore;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import com.bookstore.service.BookstoreService;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
public class MainApplication {
private final BookstoreService bookstoreService;
public MainApplication(BookstoreService bookstoreService) {
this.bookstoreService = bookstoreService;
}
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
@Bean
public ApplicationRunner init() {
return args -> {
List<AuthorDto> authors = bookstoreService.fetchAuthors();
System.out.println("Number of authors:" + authors.size());
for (AuthorDto author : authors) {
System.out.println("Author name: " + author.name()
+ " | Age: " + author.age());
}
};
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/dto/AuthorDto.java | Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/dto/AuthorDto.java | package com.bookstore.dto;
public record AuthorDto(String name, int age) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/service/BookstoreService.java | Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/service/BookstoreService.java | package com.bookstore.service;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import com.bookstore.repository.AuthorRepository;
import org.springframework.stereotype.Service;
@Service
public class BookstoreService {
private final AuthorRepository authorRepository;
public BookstoreService(AuthorRepository authorRepository) {
this.authorRepository = authorRepository;
}
public List<AuthorDto> fetchAuthors() {
return authorRepository.fetchAuthors();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/repository/AuthorRepository.java | Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/repository/AuthorRepository.java | package com.bookstore.repository;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import com.bookstore.entity.Author;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.transaction.annotation.Transactional;
@Repository
public interface AuthorRepository extends JpaRepository<Author, Long> {
@Transactional(readOnly = true)
@Query(value = "SELECT new com.bookstore.dto.AuthorDto(a.name, a.age) FROM Author a")
List<AuthorDto> fetchAuthors();
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/entity/Author.java | Chapter04/P105_DtoRecordConstructorExpression/src/main/java/com/bookstore/entity/Author.java | package com.bookstore.entity;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import java.io.Serializable;
@Entity
public class Author implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private int age;
private String name;
private String genre;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGenre() {
return genre;
}
public void setGenre(String genre) {
this.genre = genre;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Author{" + "id=" + id + ", age=" + age
+ ", name=" + name + ", genre=" + genre + '}';
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/MainApplication.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/MainApplication.java | package modern.challenge;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.ConfigurationPropertiesScan;
@SpringBootApplication
@ConfigurationPropertiesScan
public class MainApplication {
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/controller/BookstoreController.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/controller/BookstoreController.java | package modern.challenge.controller;
import modern.challenge.service.BookstoreService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class BookstoreController {
private final BookstoreService bookstoreService;
public BookstoreController(BookstoreService bookstoreService) {
this.bookstoreService = bookstoreService;
}
@GetMapping("/authors")
public String fetchBestSeller() {
return bookstoreService.fetchBestSeller();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/service/BookstoreService.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/service/BookstoreService.java | package modern.challenge.service;
import org.springframework.stereotype.Service;
import modern.challenge.record.BestSellerConfig;
@Service
public class BookstoreService {
private final BestSellerConfig bestSeller;
public BookstoreService(BestSellerConfig bestSeller) {
this.bestSeller = bestSeller;
}
public String fetchBestSeller() {
return bestSeller.author() + " | " + bestSeller.book();
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/Book.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/Book.java | package modern.challenge.record;
public record Book(String title, String isbn) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/BestSellerConfig.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/BestSellerConfig.java | package modern.challenge.record;
import org.springframework.boot.context.properties.ConfigurationProperties;
@ConfigurationProperties(prefix = "bookstore.bestseller")
public record BestSellerConfig(String author, String book) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/Author.java | Chapter04/P104_JavaRecordsInConfigs/src/main/java/modern/challenge/record/Author.java | package modern.challenge.record;
import java.util.List;
public record Author(String name, String genre, List<Book> books) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/MelonRecord.java | Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/MelonRecord.java | package modern.challenge;
public record MelonRecord(String type, float weight) {
// explicit canonical constructor for validations
public MelonRecord(String type, float weight) {
if (type == null) {
throw new IllegalArgumentException("The melon's type cannot be null");
}
if (weight < 1000 || weight > 10000) {
throw new IllegalArgumentException("The melon's weight must be between 1000 and 10000 grams");
}
this.type = type;
this.weight = weight;
}
// explicit canonical constructor for reassigning components
/*
public MelonRecord(String type, float weight) {
weight = weight/1_000; // overwriting the component 'weight'
this.type = type;
this.weight = weight;
}
*/
// explicit compact constructor for validations
/*
public MelonRecord {
if (type == null) {
throw new IllegalArgumentException("The melon's type cannot be null");
}
if (weight < 1000 || weight > 10000) {
throw new IllegalArgumentException("The melon's weight must be between 1000 and 10000 grams");
}
}
*/
// explicit compact constructor for reassigning components
/*
public MelonRecord {
weight = weight/1_000; // overwriting the component 'weight'
}
*/
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/MarketRecord.java | Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/MarketRecord.java | package modern.challenge;
import java.util.Map;
public record MarketRecord(Map<String, Integer> retails) {
public MarketRecord {
retails.putIfAbsent("Celery", 4); // this is allowed
retails = Map.copyOf(retails);
// retails.putIfAbsent("Lemon", 11); // this is not allowed
}
public Map<String, Integer> retails() {
return Map.copyOf(retails);
}
// or, getter in Java Bean style
public Map<String, Integer> getRetails() {
return Map.copyOf(retails);
}
} | java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/Main.java | Chapter04/P89_RecordCanonicalCntr/src/main/java/modern/challenge/Main.java | package modern.challenge;
import java.util.HashMap;
import java.util.Map;
public class Main {
public static void main(String[] args) {
MelonRecord melon = new MelonRecord("Cantaloupe", 2600);
System.out.println(melon);
System.out.println(melon.type());
System.out.println(melon.weight());
Map<String, Integer> retails = new HashMap<>();
retails.put("Gac", 10);
retails.put("Cucumber", 5);
retails.put("Eggplant", 8);
MarketRecord market = new MarketRecord(retails);
System.out.println(retails);
System.out.println(market.retails());
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_RecordAndEmbeddables/src/main/java/com/bookstore/MainApplication.java | Chapter04/P105_RecordAndEmbeddables/src/main/java/com/bookstore/MainApplication.java | package com.bookstore;
import com.bookstore.dto.AuthorDto;
import java.util.List;
import com.bookstore.service.BookstoreService;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
@SpringBootApplication
public class MainApplication {
private final BookstoreService bookstoreService;
public MainApplication(BookstoreService bookstoreService) {
this.bookstoreService = bookstoreService;
}
public static void main(String[] args) {
SpringApplication.run(MainApplication.class, args);
}
@Bean
public ApplicationRunner init() {
return args -> {
List<AuthorDto> authors = bookstoreService.fetchByGenre();
System.out.println(authors);
};
}
}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
PacktPublishing/Java-Coding-Problems-Second-Edition | https://github.com/PacktPublishing/Java-Coding-Problems-Second-Edition/blob/47b7c834407a607580baf8e3a23c1c24c24b8bc0/Chapter04/P105_RecordAndEmbeddables/src/main/java/com/bookstore/dto/AuthorDto.java | Chapter04/P105_RecordAndEmbeddables/src/main/java/com/bookstore/dto/AuthorDto.java | package com.bookstore.dto;
import com.bookstore.embeddable.Contact;
public record AuthorDto(String name, int age, Contact contact) {}
| java | MIT | 47b7c834407a607580baf8e3a23c1c24c24b8bc0 | 2026-01-05T02:37:06.170961Z | false |
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