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iluwatar_java-design-patterns
java-design-patterns/page-object/sample-application/src/main/java/com/iluwatar/pageobject/App.java
App
main
class App { private App() { } /** * Application entry point * * <p>The application under development is a web application. Normally you would probably have a * backend that is probably implemented in an object-oriented language (e.g. Java) that serves the * frontend which comprises of a series of...
try { var classLoader = App.class.getClassLoader(); var applicationFile = new File(classLoader.getResource("sample-ui/login.html").getPath()); // should work for unix like OS (mac, unix etc...) if (Desktop.isDesktopSupported()) { Desktop.getDesktop().open(applicationFile); ...
174
162
336
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/parameter-object/src/main/java/com/iluwatar/parameter/object/App.java
App
main
class App { private static final Logger LOGGER = LoggerFactory.getLogger(App.class); /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
ParameterObject params = ParameterObject.newBuilder() .withType("sneakers") .sortBy("brand") .build(); LOGGER.info(params.toString()); LOGGER.info(new SearchService().search(params));
78
66
144
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/parameter-object/src/main/java/com/iluwatar/parameter/object/SearchService.java
SearchService
getQuerySummary
class SearchService { /** * Below two methods of name `search` is overloaded so that we can send a default value for * one of the criteria and call the final api. A default SortOrder is sent in the first method * and a default SortBy is sent in the second method. So two separate method definitions are * ...
return String.format("Requesting shoes of type \"%s\" sorted by \"%s\" in \"%sending\" order..", type, sortBy, sortOrder.getValue());
326
50
376
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/partial-response/src/main/java/com/iluwatar/partialresponse/App.java
App
main
class App { /** * Method as act client and request to server for video details. * * @param args program argument. */ public static void main(String[] args) throws Exception {<FILL_FUNCTION_BODY>} }
var videos = Map.of( 1, new Video(1, "Avatar", 178, "epic science fiction film", "James Cameron", "English"), 2, new Video(2, "Godzilla Resurgence", 120, "Action & drama movie|", "Hideaki Anno", "Japanese"), 3, new Video(3, "Interstellar", 169, "Adventure & Sci-Fi", ...
66
336
402
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/partial-response/src/main/java/com/iluwatar/partialresponse/FieldJsonMapper.java
FieldJsonMapper
getString
class FieldJsonMapper { /** * Gets json of required fields from video. * * @param video object containing video information * @param fields fields information to get * @return json of required fields from video */ public String toJson(Video video, String[] fields) throws Exception { var json...
declaredField.setAccessible(true); var value = declaredField.get(video); if (declaredField.get(video) instanceof Integer) { return "\"" + declaredField.getName() + "\"" + ": " + value; } return "\"" + declaredField.getName() + "\"" + ": " + "\"" + value.toString() + "\"";
226
96
322
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/pipeline/src/main/java/com/iluwatar/pipeline/App.java
App
main
class App { /** * Specify the initial input type for the first stage handler and the expected output type of the * last stage handler as type parameters for Pipeline. Use the fluent builder by calling * addHandler to add more stage handlers on the pipeline. */ public static void main(String[] args) {<FI...
/* Suppose we wanted to pass through a String to a series of filtering stages and convert it as a char array on the last stage. - Stage handler 1 (pipe): Removing the alphabets, accepts a String input and returns the processed String output. This will be used by the next handler as its inp...
92
319
411
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/pipeline/src/main/java/com/iluwatar/pipeline/ConvertToCharArrayHandler.java
ConvertToCharArrayHandler
process
class ConvertToCharArrayHandler implements Handler<String, char[]> { private static final Logger LOGGER = LoggerFactory.getLogger(ConvertToCharArrayHandler.class); @Override public char[] process(String input) {<FILL_FUNCTION_BODY>} }
var characters = input.toCharArray(); var string = Arrays.toString(characters); LOGGER.info( String.format("Current handler: %s, input is %s of type %s, output is %s, of type %s", ConvertToCharArrayHandler.class, input, String.class, string, Character[].class) ); return charact...
73
97
170
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/pipeline/src/main/java/com/iluwatar/pipeline/RemoveAlphabetsHandler.java
RemoveAlphabetsHandler
process
class RemoveAlphabetsHandler implements Handler<String, String> { private static final Logger LOGGER = LoggerFactory.getLogger(RemoveAlphabetsHandler.class); @Override public String process(String input) {<FILL_FUNCTION_BODY>} }
var inputWithoutAlphabets = new StringBuilder(); var isAlphabetic = (IntPredicate) Character::isAlphabetic; input.chars() .filter(isAlphabetic.negate()) .mapToObj(x -> (char) x) .forEachOrdered(inputWithoutAlphabets::append); var inputWithoutAlphabetsStr = inputWithoutAlphabets...
73
201
274
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/pipeline/src/main/java/com/iluwatar/pipeline/RemoveDigitsHandler.java
RemoveDigitsHandler
process
class RemoveDigitsHandler implements Handler<String, String> { private static final Logger LOGGER = LoggerFactory.getLogger(RemoveDigitsHandler.class); @Override public String process(String input) {<FILL_FUNCTION_BODY>} }
var inputWithoutDigits = new StringBuilder(); var isDigit = (IntPredicate) Character::isDigit; input.chars() .filter(isDigit.negate()) .mapToObj(x -> (char) x) .forEachOrdered(inputWithoutDigits::append); var inputWithoutDigitsStr = inputWithoutDigits.toString(); LOGGER.inf...
69
179
248
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/poison-pill/src/main/java/com/iluwatar/poison/pill/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var queue = new SimpleMessageQueue(10000); final var producer = new Producer("PRODUCER_1", queue); final var consumer = new Consumer("CONSUMER_1", queue); new Thread(consumer::consume).start(); new Thread(() -> { producer.send("hand shake"); producer.send("some very important informa...
56
122
178
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/poison-pill/src/main/java/com/iluwatar/poison/pill/Consumer.java
Consumer
consume
class Consumer { private final MqSubscribePoint queue; private final String name; public Consumer(String name, MqSubscribePoint queue) { this.name = name; this.queue = queue; } /** * Consume message. */ public void consume() {<FILL_FUNCTION_BODY>} }
while (true) { try { var msg = queue.take(); if (Message.POISON_PILL.equals(msg)) { LOGGER.info("Consumer {} receive request to terminate.", name); break; } var sender = msg.getHeader(Headers.SENDER); var body = msg.getBody(); LOGGER.info("M...
96
158
254
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/poison-pill/src/main/java/com/iluwatar/poison/pill/Producer.java
Producer
send
class Producer { private final MqPublishPoint queue; private final String name; private boolean isStopped; /** * Constructor. */ public Producer(String name, MqPublishPoint queue) { this.name = name; this.queue = queue; this.isStopped = false; } /** * Send message to queue. */ ...
if (isStopped) { throw new IllegalStateException(String.format( "Producer %s was stopped and fail to deliver requested message [%s].", body, name)); } var msg = new SimpleMessage(); msg.addHeader(Headers.DATE, new Date().toString()); msg.addHeader(Headers.SENDER, name); msg.setB...
217
146
363
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/presentation-model/src/main/java/com/iluwatar/presentationmodel/DisplayedAlbums.java
DisplayedAlbums
addAlbums
class DisplayedAlbums { /** * albums a list of albums. */ private final List<Album> albums; /** * a constructor method. */ public DisplayedAlbums() { this.albums = new ArrayList<>(); } /** * a method used to add a new album to album list. * * @param title the title of the al...
if (isClassical) { this.albums.add(new Album(title, artist, true, composer)); } else { this.albums.add(new Album(title, artist, false, "")); }
217
65
282
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/presentation-model/src/main/java/com/iluwatar/presentationmodel/PresentationModel.java
PresentationModel
getAlbumList
class PresentationModel { /** * the data of all albums that will be shown. */ private final DisplayedAlbums data; /** * the no of selected album. */ private int selectedAlbumNumber; /** * the selected album. */ private Album selectedAlbum; /** * Generates a set of data for testing. ...
var result = new String[data.getAlbums().size()]; for (var i = 0; i < result.length; i++) { result[i] = data.getAlbums().get(i).getTitle(); } return result;
1,248
69
1,317
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/presentation-model/src/main/java/com/iluwatar/presentationmodel/View.java
View
createView
class View { /** * the model that controls this view. */ private final PresentationModel model; /** * the filed to show and modify title. */ private TextField txtTitle; /** * the filed to show and modify the name of artist. */ private TextField txtArtist; /** * the checkbox for is c...
var frame = new JFrame("Album"); var b1 = Box.createHorizontalBox(); frame.add(b1); albumList = new JList<>(model.getAlbumList()); albumList.addMouseListener(new MouseAdapter() { @Override public void mouseClicked(final MouseEvent e) { model.setSelectedAlbumNumber(albumList.get...
628
577
1,205
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/priority-queue/src/main/java/com/iluwatar/priority/queue/Application.java
Application
main
class Application { /** * main entry. */ public static void main(String[] args) throws Exception {<FILL_FUNCTION_BODY>} }
var queueManager = new QueueManager(10); // push some message to queue // Low Priority message for (var i = 0; i < 10; i++) { queueManager.publishMessage(new Message("Low Message Priority", 0)); } // High Priority message for (var i = 0; i < 10; i++) { queueManager.publishMes...
44
150
194
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/priority-queue/src/main/java/com/iluwatar/priority/queue/Message.java
Message
toString
class Message implements Comparable<Message> { private final String message; private final int priority; // define message priority in queue public Message(String message, int priority) { this.message = message; this.priority = priority; } @Override public int compareTo(Message o) { return pr...
return "Message{" + "message='" + message + '\'' + ", priority=" + priority + '}';
121
36
157
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/priority-queue/src/main/java/com/iluwatar/priority/queue/PriorityMessageQueue.java
PriorityMessageQueue
maxHeapifyUp
class PriorityMessageQueue<T extends Comparable> { private int size = 0; private int capacity; private T[] queue; public PriorityMessageQueue(T[] queue) { this.queue = queue; this.capacity = queue.length; } /** * Remove top message from queue. */ public T remove() { if (isEmpty()) ...
var index = size - 1; while (hasParent(index) && parent(index).compareTo(queue[index]) < 0) { swap(parentIndex(index), index); index = parentIndex(index); }
873
61
934
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/priority-queue/src/main/java/com/iluwatar/priority/queue/Worker.java
Worker
run
class Worker { private final QueueManager queueManager; public Worker(QueueManager queueManager) { this.queueManager = queueManager; } /** * Keep checking queue for message. */ @SuppressWarnings("squid:S2189") public void run() throws Exception {<FILL_FUNCTION_BODY>} /** * Process message...
while (true) { var message = queueManager.receiveMessage(); if (message == null) { LOGGER.info("No Message ... waiting"); Thread.sleep(200); } else { processMessage(message); } }
138
71
209
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/private-class-data/src/main/java/com/iluwatar/privateclassdata/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
// stew is mutable var stew = new Stew(1, 2, 3, 4); stew.mix(); stew.taste(); stew.mix(); // immutable stew protected with Private Class Data pattern var immutableStew = new ImmutableStew(2, 4, 3, 6); immutableStew.mix();
56
102
158
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/private-class-data/src/main/java/com/iluwatar/privateclassdata/ImmutableStew.java
ImmutableStew
mix
class ImmutableStew { private final StewData data; public ImmutableStew(int numPotatoes, int numCarrots, int numMeat, int numPeppers) { data = new StewData(numPotatoes, numCarrots, numMeat, numPeppers); } /** * Mix the stew. */ public void mix() {<FILL_FUNCTION_BODY>} }
LOGGER .info("Mixing the immutable stew we find: {} potatoes, {} carrots, {} meat and {} peppers", data.numPotatoes(), data.numCarrots(), data.numMeat(), data.numPeppers());
117
66
183
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/private-class-data/src/main/java/com/iluwatar/privateclassdata/Stew.java
Stew
mix
class Stew { private int numPotatoes; private int numCarrots; private int numMeat; private int numPeppers; /** * Constructor. */ public Stew(int numPotatoes, int numCarrots, int numMeat, int numPeppers) { this.numPotatoes = numPotatoes; this.numCarrots = numCarrots; this.num...
LOGGER.info("Mixing the stew we find: {} potatoes, {} carrots, {} meat and {} peppers", numPotatoes, numCarrots, numMeat, numPeppers);
346
57
403
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/producer-consumer/src/main/java/com/iluwatar/producer/consumer/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var queue = new ItemQueue(); var executorService = Executors.newFixedThreadPool(5); for (var i = 0; i < 2; i++) { final var producer = new Producer("Producer_" + i, queue); executorService.submit(() -> { while (true) { producer.produce(); } }); } for ...
56
244
300
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/producer-consumer/src/main/java/com/iluwatar/producer/consumer/Consumer.java
Consumer
consume
class Consumer { private final ItemQueue queue; private final String name; public Consumer(String name, ItemQueue queue) { this.name = name; this.queue = queue; } /** * Consume item from the queue. */ public void consume() throws InterruptedException {<FILL_FUNCTION_BODY>} }
var item = queue.take(); LOGGER.info("Consumer [{}] consume item [{}] produced by [{}]", name, item.id(), item.producer());
98
48
146
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/promise/src/main/java/com/iluwatar/promise/App.java
App
calculateLowestFrequencyChar
class App { private static final String DEFAULT_URL = "https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/promise/README.md"; private final ExecutorService executor; private final CountDownLatch stopLatch; private App() { executor = Executors.newFixedThreadPool(2); stopLatch ...
lowestFrequencyChar().thenAccept( charFrequency -> { LOGGER.info("Char with lowest frequency is: {}", charFrequency); taskCompleted(); } );
804
52
856
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/promise/src/main/java/com/iluwatar/promise/Promise.java
TransformAction
run
class TransformAction<V> implements Runnable { private final Promise<T> src; private final Promise<V> dest; private final Function<? super T, V> func; private TransformAction(Promise<T> src, Promise<V> dest, Function<? super T, V> func) { this.src = src; this.dest = dest; this.func =...
try { dest.fulfill(func.apply(src.get())); } catch (Throwable throwable) { dest.fulfillExceptionally((Exception) throwable.getCause()); }
133
54
187
<methods>public boolean cancel(boolean) ,public T get() throws java.lang.InterruptedException, java.util.concurrent.ExecutionException,public T get(long, java.util.concurrent.TimeUnit) throws java.util.concurrent.ExecutionException,public boolean isCancelled() ,public boolean isDone() <variables>private static final in...
iluwatar_java-design-patterns
java-design-patterns/promise/src/main/java/com/iluwatar/promise/PromiseSupport.java
PromiseSupport
get
class PromiseSupport<T> implements Future<T> { private static final Logger LOGGER = LoggerFactory.getLogger(PromiseSupport.class); private static final int RUNNING = 1; private static final int FAILED = 2; private static final int COMPLETED = 3; private final Object lock; private volatile int state = RU...
synchronized (lock) { while (state == RUNNING) { try { lock.wait(unit.toMillis(timeout)); } catch (InterruptedException e) { LOGGER.warn("Interrupted!", e); Thread.currentThread().interrupt(); } } } if (state == COMPLETED) { return va...
426
115
541
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/promise/src/main/java/com/iluwatar/promise/Utility.java
Utility
downloadFile
class Utility { /** * Calculates character frequency of the file provided. * * @param fileLocation location of the file. * @return a map of character to its frequency, an empty map if file does not exist. */ public static Map<Character, Long> characterFrequency(String fileLocation) { try (var bu...
LOGGER.info("Downloading contents from url: {}", urlString); var url = new URL(urlString); var file = File.createTempFile("promise_pattern", null); try (var bufferedReader = new BufferedReader(new InputStreamReader(url.openStream())); var writer = new FileWriter(file)) { String line; ...
500
161
661
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/property/src/main/java/com/iluwatar/property/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
/* set up */ var charProto = new Character(); charProto.set(Stats.STRENGTH, 10); charProto.set(Stats.AGILITY, 10); charProto.set(Stats.ARMOR, 10); charProto.set(Stats.ATTACK_POWER, 10); var mageProto = new Character(Type.MAGE, charProto); mageProto.set(Stats.INTELLECT, 15); magePro...
56
430
486
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/property/src/main/java/com/iluwatar/property/Character.java
Character
toString
class Character implements Prototype { /** * Enumeration of Character types. */ public enum Type { WARRIOR, MAGE, ROGUE } private final Prototype prototype; private final Map<Stats, Integer> properties = new HashMap<>(); private String name; private Type type; /** * Constructor. */ ...
var builder = new StringBuilder(); if (name != null) { builder.append("Player: ").append(name).append('\n'); } if (type != null) { builder.append("Character type: ").append(type.name()).append('\n'); } builder.append("Stats:\n"); for (var stat : Stats.values()) { var val...
521
169
690
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/prototype/src/main/java/com/iluwatar/prototype/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var factory = new HeroFactoryImpl( new ElfMage("cooking"), new ElfWarlord("cleaning"), new ElfBeast("protecting") ); var mage = factory.createMage(); var warlord = factory.createWarlord(); var beast = factory.createBeast(); LOGGER.info(mage.toString()); LOGGER.info(w...
56
238
294
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/proxy/src/main/java/com/iluwatar/proxy/App.java
App
main
class App { /** * Program entry point. */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var proxy = new WizardTowerProxy(new IvoryTower()); proxy.enter(new Wizard("Red wizard")); proxy.enter(new Wizard("White wizard")); proxy.enter(new Wizard("Black wizard")); proxy.enter(new Wizard("Green wizard")); proxy.enter(new Wizard("Brown wizard"));
44
95
139
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/proxy/src/main/java/com/iluwatar/proxy/WizardTowerProxy.java
WizardTowerProxy
enter
class WizardTowerProxy implements WizardTower { private static final int NUM_WIZARDS_ALLOWED = 3; private int numWizards; private final WizardTower tower; public WizardTowerProxy(WizardTower tower) { this.tower = tower; } @Override public void enter(Wizard wizard) {<FILL_FUNCTION_BODY>} }
if (numWizards < NUM_WIZARDS_ALLOWED) { tower.enter(wizard); numWizards++; } else { LOGGER.info("{} is not allowed to enter!", wizard); }
115
68
183
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/App.java
App
main
class App { //Executor shut down time limit. private static final int SHUTDOWN_TIME = 15; /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
// An Executor that provides methods to manage termination and methods that can // produce a Future for tracking progress of one or more asynchronous tasks. ExecutorService executor = null; try { // Create a MessageQueue object. var msgQueue = new MessageQueue(); LOGGER.info("Subm...
82
473
555
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/MessageQueue.java
MessageQueue
submitMsg
class MessageQueue { private final BlockingQueue<Message> blkQueue; // Default constructor when called creates Blocking Queue object. public MessageQueue() { this.blkQueue = new ArrayBlockingQueue<>(1024); } /** * All the TaskGenerator threads will call this method to insert the Messages in to the ...
try { if (null != msg) { blkQueue.add(msg); } } catch (Exception e) { LOGGER.error(e.getMessage()); }
231
53
284
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/ServiceExecutor.java
ServiceExecutor
run
class ServiceExecutor implements Runnable { private final MessageQueue msgQueue; public ServiceExecutor(MessageQueue msgQueue) { this.msgQueue = msgQueue; } /** * The ServiceExecutor thread will retrieve each message and process it. */ public void run() {<FILL_FUNCTION_BODY>} }
try { while (!Thread.currentThread().isInterrupted()) { var msg = msgQueue.retrieveMsg(); if (null != msg) { LOGGER.info(msg.toString() + " is served."); } else { LOGGER.info("Service Executor: Waiting for Messages to serve .. "); } Thread.sleep(1...
88
126
214
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/queue-load-leveling/src/main/java/com/iluwatar/queue/load/leveling/TaskGenerator.java
TaskGenerator
run
class TaskGenerator implements Task, Runnable { // MessageQueue reference using which we will submit our messages. private final MessageQueue msgQueue; // Total message count that a TaskGenerator will submit. private final int msgCount; // Parameterized constructor. public TaskGenerator(MessageQueue msgQ...
var count = this.msgCount; try { while (count > 0) { var statusMsg = "Message-" + count + " submitted by " + Thread.currentThread().getName(); this.submit(new Message(statusMsg)); LOGGER.info(statusMsg); // reduce the message count. count--; // Make the...
239
140
379
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/app/App.java
App
start
class App { private NioReactor reactor; private final List<AbstractNioChannel> channels = new ArrayList<>(); private final Dispatcher dispatcher; /** * Creates an instance of App which will use provided dispatcher for dispatching events on * reactor. * * @param dispatcher the dispatcher that will ...
/* * The application can customize its event dispatching mechanism. */ reactor = new NioReactor(dispatcher); /* * This represents application specific business logic that dispatcher will call on appropriate * events. These events are read events in our example. */ var loggingH...
452
198
650
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/app/AppClient.java
UdpLoggingClient
run
class UdpLoggingClient implements Runnable { private final String clientName; private final InetSocketAddress remoteAddress; /** * Creates a new UDP logging client. * * @param clientName the name of the client to be sent in logging requests. * @param port the port on which client ...
try (var socket = new DatagramSocket()) { for (var i = 0; i < 4; i++) { var message = clientName + " - Log request: " + i; var bytes = message.getBytes(); var request = new DatagramPacket(bytes, bytes.length, remoteAddress); socket.send(request); var d...
185
229
414
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/app/LoggingHandler.java
LoggingHandler
handleChannelRead
class LoggingHandler implements ChannelHandler { private static final byte[] ACK = "Data logged successfully".getBytes(); /** * Decodes the received data and logs it on standard console. */ @Override public void handleChannelRead(AbstractNioChannel channel, Object readObject, SelectionKey key) {<FILL_FU...
/* * As this handler is attached with both TCP and UDP channels we need to check whether the data * received is a ByteBuffer (from TCP channel) or a DatagramPacket (from UDP channel). */ if (readObject instanceof ByteBuffer) { doLogging((ByteBuffer) readObject); sendReply(channel, ke...
313
164
477
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/framework/AbstractNioChannel.java
AbstractNioChannel
flush
class AbstractNioChannel { private final SelectableChannel channel; private final ChannelHandler handler; private final Map<SelectableChannel, Queue<Object>> channelToPendingWrites; private NioReactor reactor; /** * Creates a new channel. * * @param handler which will handle events occurring on thi...
var pendingWrites = channelToPendingWrites.get(key.channel()); Object pendingWrite; while ((pendingWrite = pendingWrites.poll()) != null) { // ask the concrete channel to make sense of data and write it to java channel doWrite(pendingWrite, key); } // We don't have anything more to writ...
1,021
118
1,139
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/framework/NioDatagramChannel.java
NioDatagramChannel
read
class NioDatagramChannel extends AbstractNioChannel { private final int port; /** * Creates a {@link DatagramChannel} which will bind at provided port and use <code>handler</code> * to handle incoming events on this channel. * * <p>Note the constructor does not bind the socket, {@link #bind()} method ...
var buffer = ByteBuffer.allocate(1024); var sender = ((DatagramChannel) key.channel()).receive(buffer); /* * It is required to create a DatagramPacket because we need to preserve which socket address * acts as destination for sending reply packets. */ buffer.flip(); var packet = new...
1,105
114
1,219
<methods>public void <init>(com.iluwatar.reactor.framework.ChannelHandler, java.nio.channels.SelectableChannel) ,public abstract void bind() throws java.io.IOException,public com.iluwatar.reactor.framework.ChannelHandler getHandler() ,public abstract int getInterestedOps() ,public java.nio.channels.SelectableChannel ge...
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/framework/NioReactor.java
NioReactor
start
class NioReactor { private final Selector selector; private final Dispatcher dispatcher; /** * All the work of altering the SelectionKey operations and Selector operations are performed in * the context of main event loop of reactor. So when any channel needs to change its readability * or writability, ...
reactorMain.execute(() -> { try { LOGGER.info("Reactor started, waiting for events..."); eventLoop(); } catch (IOException e) { LOGGER.error("exception in event loop", e); } });
1,704
68
1,772
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reactor/src/main/java/com/iluwatar/reactor/framework/SameThreadDispatcher.java
SameThreadDispatcher
onChannelReadEvent
class SameThreadDispatcher implements Dispatcher { /** * Dispatches the read event in the context of caller thread. <br> Note this is a blocking call. * It returns only after the associated handler has handled the read event. */ @Override public void onChannelReadEvent(AbstractNioChannel channel, Object...
/* * Calls the associated handler to notify the read event where application specific code * resides. */ channel.getHandler().handleChannelRead(channel, readObject, key);
138
50
188
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reader-writer-lock/src/main/java/com/iluwatar/reader/writer/lock/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var executeService = Executors.newFixedThreadPool(10); var lock = new ReaderWriterLock(); // Start writers for (var i = 0; i < 5; i++) { var writingTime = ThreadLocalRandom.current().nextLong(5000); executeService.submit(new Writer("Writer " + i, lock.writeLock(), writingTime)); } ...
57
434
491
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reader-writer-lock/src/main/java/com/iluwatar/reader/writer/lock/Reader.java
Reader
run
class Reader implements Runnable { private final Lock readLock; private final String name; private final long readingTime; /** * Create new Reader. * * @param name - Name of the thread owning the reader * @param readLock - Lock for this reader * @param readingTime - amount of time (...
readLock.lock(); try { read(); } catch (InterruptedException e) { LOGGER.info("InterruptedException when reading", e); Thread.currentThread().interrupt(); } finally { readLock.unlock(); }
331
69
400
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reader-writer-lock/src/main/java/com/iluwatar/reader/writer/lock/ReaderWriterLock.java
ReadLock
unlock
class ReadLock implements Lock { @Override public void lock() { synchronized (readerMutex) { currentReaderCount++; if (currentReaderCount == 1) { acquireForReaders(); } } } /** * Acquire the globalMutex lock on behalf of current and future concurrent ...
synchronized (readerMutex) { currentReaderCount--; // Release the lock only when it is the last reader, it is ensure that the lock is released // when all reader is completely. if (currentReaderCount == 0) { synchronized (globalMutex) { // Notify the waiter, ...
412
113
525
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/reader-writer-lock/src/main/java/com/iluwatar/reader/writer/lock/Writer.java
Writer
run
class Writer implements Runnable { private final Lock writeLock; private final String name; private final long writingTime; /** * Create new Writer who writes for 250ms. * * @param name - Name of the thread owning the writer * @param writeLock - Lock for this writer */ public Writer(St...
writeLock.lock(); try { write(); } catch (InterruptedException e) { LOGGER.info("InterruptedException when writing", e); Thread.currentThread().interrupt(); } finally { writeLock.unlock(); }
337
69
406
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/registry/src/main/java/com/iluwatar/registry/App.java
App
main
class App { private static final Logger LOGGER = LoggerFactory.getLogger(App.class); /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
CustomerRegistry customerRegistry = CustomerRegistry.getInstance(); var john = new Customer("1", "John"); customerRegistry.addCustomer(john); var julia = new Customer("2", "Julia"); customerRegistry.addCustomer(julia); LOGGER.info("John {}", customerRegistry.getCustomer("1")); LOGGER.info...
79
106
185
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/repository/src/main/java/com/iluwatar/repository/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var context = new ClassPathXmlApplicationContext("applicationContext.xml"); var repository = context.getBean(PersonRepository.class); var peter = new Person("Peter", "Sagan", 17); var nasta = new Person("Nasta", "Kuzminova", 25); var john = new Person("John", "lawrence", 35); var terry = new ...
56
480
536
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/repository/src/main/java/com/iluwatar/repository/AppConfig.java
AppConfig
main
class AppConfig { /** * Creation of H2 db. * * @return A new Instance of DataSource */ @Bean(destroyMethod = "close") public DataSource dataSource() { var basicDataSource = new BasicDataSource(); basicDataSource.setDriverClassName("org.h2.Driver"); basicDataSource.setUrl("jdbc:h2:mem:data...
var context = new AnnotationConfigApplicationContext(AppConfig.class); var repository = context.getBean(PersonRepository.class); var peter = new Person("Peter", "Sagan", 17); var nasta = new Person("Nasta", "Kuzminova", 25); var john = new Person("John", "lawrence", 35); var terry = new Person...
481
471
952
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/resource-acquisition-is-initialization/src/main/java/com/iluwatar/resource/acquisition/is/initialization/App.java
App
main
class App { /** * Program entry point. */ public static void main(String[] args) throws Exception {<FILL_FUNCTION_BODY>} }
try (var ignored = new SlidingDoor()) { LOGGER.info("Walking in."); } try (var ignored = new TreasureChest()) { LOGGER.info("Looting contents."); }
46
62
108
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/retry/src/main/java/com/iluwatar/retry/App.java
App
errorWithRetry
class App { private static final Logger LOG = LoggerFactory.getLogger(App.class); public static final String NOT_FOUND = "not found"; private static BusinessOperation<String> op; /** * Entry point. * * @param args not used * @throws Exception not expected */ public static void main(String[] ar...
final var retry = new Retry<>( new FindCustomer("123", new CustomerNotFoundException(NOT_FOUND)), 3, //3 attempts 100, //100 ms delay between attempts e -> CustomerNotFoundException.class.isAssignableFrom(e.getClass()) ); op = retry; final var customerId = op.perform();...
474
161
635
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/retry/src/main/java/com/iluwatar/retry/Retry.java
Retry
perform
class Retry<T> implements BusinessOperation<T> { private final BusinessOperation<T> op; private final int maxAttempts; private final long delay; private final AtomicInteger attempts; private final Predicate<Exception> test; private final List<Exception> errors; /** * Ctor. * * @param op ...
do { try { return this.op.perform(); } catch (BusinessException e) { this.errors.add(e); if (this.attempts.incrementAndGet() >= this.maxAttempts || !this.test.test(e)) { throw e; } try { Thread.sleep(this.delay); } catch (Interrupted...
448
126
574
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/retry/src/main/java/com/iluwatar/retry/RetryExponentialBackoff.java
RetryExponentialBackoff
perform
class RetryExponentialBackoff<T> implements BusinessOperation<T> { private static final Random RANDOM = new Random(); private final BusinessOperation<T> op; private final int maxAttempts; private final long maxDelay; private final AtomicInteger attempts; private final Predicate<Exception> test; private fi...
do { try { return this.op.perform(); } catch (BusinessException e) { this.errors.add(e); if (this.attempts.incrementAndGet() >= this.maxAttempts || !this.test.test(e)) { throw e; } try { var testDelay = (long) Math.pow(2, this.attempts()) * ...
457
181
638
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/role-object/src/main/java/com/iluwatar/roleobject/ApplicationRoleObject.java
ApplicationRoleObject
main
class ApplicationRoleObject { /** * Main entry point. * * @param args program arguments */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var customer = Customer.newCustomer(Borrower, Investor); LOGGER.info(" the new customer created : {}", customer); var hasBorrowerRole = customer.hasRole(Borrower); LOGGER.info(" customer has a borrowed role - {}", hasBorrowerRole); var hasInvestorRole = customer.hasRole(Investor); LOGGER.info...
57
293
350
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/role-object/src/main/java/com/iluwatar/roleobject/BorrowerRole.java
BorrowerRole
borrow
class BorrowerRole extends CustomerRole { private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } public String borrow() {<FILL_FUNCTION_BODY>} }
return String.format("Borrower %s wants to get some money.", name);
80
23
103
<methods>public non-sealed void <init>() <variables>
iluwatar_java-design-patterns
java-design-patterns/role-object/src/main/java/com/iluwatar/roleobject/CustomerCore.java
CustomerCore
toString
class CustomerCore extends Customer { private final Map<Role, CustomerRole> roles; public CustomerCore() { roles = new HashMap<>(); } @Override public boolean addRole(Role role) { return role .instance() .map(inst -> { roles.put(role, inst); return true; ...
var roles = Arrays.toString(this.roles.keySet().toArray()); return "Customer{roles=" + roles + "}";
268
40
308
<methods>public non-sealed void <init>() ,public abstract boolean addRole(com.iluwatar.roleobject.Role) ,public abstract Optional<T> getRole(com.iluwatar.roleobject.Role, Class<T>) ,public abstract boolean hasRole(com.iluwatar.roleobject.Role) ,public static com.iluwatar.roleobject.Customer newCustomer() ,public static...
iluwatar_java-design-patterns
java-design-patterns/role-object/src/main/java/com/iluwatar/roleobject/InvestorRole.java
InvestorRole
invest
class InvestorRole extends CustomerRole { private String name; private long amountToInvest; public String getName() { return name; } public void setName(String name) { this.name = name; } public long getAmountToInvest() { return amountToInvest; } public void setAmountToInvest(long am...
return String.format("Investor %s has invested %d dollars", name, amountToInvest);
146
28
174
<methods>public non-sealed void <init>() <variables>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/choreography/Saga.java
Saga
getResult
class Saga { private final List<Chapter> chapters; private int pos; private boolean forward; private boolean finished; public static Saga create() { return new Saga(); } /** * get resuzlt of saga. * * @return result of saga @see {@link SagaResult} */ public SagaResult getResult() {<F...
if (finished) { return forward ? SagaResult.FINISHED : SagaResult.ROLLBACKED; } return SagaResult.PROGRESS;
1,053
52
1,105
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/choreography/SagaApplication.java
SagaApplication
newSaga
class SagaApplication { /** * main method. */ public static void main(String[] args) { var sd = serviceDiscovery(); var service = sd.findAny(); var goodOrderSaga = service.execute(newSaga("good_order")); var badOrderSaga = service.execute(newSaga("bad_order")); LOGGER.info("orders: goodOr...
return Saga .create() .chapter("init an order").setInValue(value) .chapter("booking a Fly") .chapter("booking a Hotel") .chapter("withdrawing Money");
251
62
313
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/choreography/Service.java
Service
isSagaFinished
class Service implements ChoreographyChapter { protected static final Logger LOGGER = LoggerFactory.getLogger(Service.class); private final ServiceDiscoveryService sd; public Service(ServiceDiscoveryService service) { this.sd = service; } @Override public Saga execute(Saga saga) { var nextSaga = ...
if (!saga.isPresent()) { saga.setFinished(true); LOGGER.info(" the saga has been finished with {} status", saga.getResult()); return true; } return false;
652
61
713
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/choreography/WithdrawMoneyService.java
WithdrawMoneyService
process
class WithdrawMoneyService extends Service { public WithdrawMoneyService(ServiceDiscoveryService service) { super(service); } @Override public String getName() { return "withdrawing Money"; } @Override public Saga process(Saga saga) {<FILL_FUNCTION_BODY>} }
var inValue = saga.getCurrentValue(); if (inValue.equals("bad_order")) { LOGGER.info("The chapter '{}' has been started. But the exception has been raised." + "The rollback is about to start", getName(), inValue); saga.setCurrentStatus(Saga.ChapterResult.ROLLBACK); re...
93
112
205
<methods>public void <init>(com.iluwatar.saga.choreography.ServiceDiscoveryService) ,public com.iluwatar.saga.choreography.Saga execute(com.iluwatar.saga.choreography.Saga) ,public com.iluwatar.saga.choreography.Saga process(com.iluwatar.saga.choreography.Saga) ,public com.iluwatar.saga.choreography.Saga rollback(com.i...
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/orchestration/HotelBookingService.java
HotelBookingService
rollback
class HotelBookingService extends Service<String> { @Override public String getName() { return "booking a Hotel"; } @Override public ChapterResult<String> rollback(String value) {<FILL_FUNCTION_BODY>} }
if (value.equals("crashed_order")) { LOGGER.info("The Rollback for a chapter '{}' has been started. " + "The data {} has been failed.The saga has been crashed.", getName(), value); return ChapterResult.failure(value); } LOGGER.info("The Rollback for a chapter '{}' has ...
71
133
204
<methods>public non-sealed void <init>() ,public abstract java.lang.String getName() ,public ChapterResult<java.lang.String> process(java.lang.String) ,public ChapterResult<java.lang.String> rollback(java.lang.String) <variables>protected static final Logger LOGGER
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/orchestration/SagaApplication.java
SagaApplication
serviceDiscovery
class SagaApplication { /** * method to show common saga logic. */ public static void main(String[] args) { var sagaOrchestrator = new SagaOrchestrator(newSaga(), serviceDiscovery()); Saga.Result goodOrder = sagaOrchestrator.execute("good_order"); Saga.Result badOrder = sagaOrchestrator.execute(...
return new ServiceDiscoveryService() .discover(new OrderService()) .discover(new FlyBookingService()) .discover(new HotelBookingService()) .discover(new WithdrawMoneyService());
267
59
326
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/orchestration/SagaOrchestrator.java
SagaOrchestrator
execute
class SagaOrchestrator { private final Saga saga; private final ServiceDiscoveryService sd; private final CurrentState state; /** * Create a new service to orchetrate sagas. * * @param saga saga to process * @param sd service discovery @see {@link ServiceDiscoveryService} */ public SagaOrch...
state.cleanUp(); LOGGER.info(" The new saga is about to start"); var result = FINISHED; K tempVal = value; while (true) { var next = state.current(); var ch = saga.get(next); var srvOpt = sd.find(ch.name); if (srvOpt.isEmpty()) { state.directionToBack(); st...
414
341
755
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/orchestration/Service.java
Service
process
class Service<K> implements OrchestrationChapter<K> { protected static final Logger LOGGER = LoggerFactory.getLogger(Service.class); @Override public abstract String getName(); @Override public ChapterResult<K> process(K value) {<FILL_FUNCTION_BODY>} @Override public ChapterResult<K> rollback(K value)...
LOGGER.info("The chapter '{}' has been started. " + "The data {} has been stored or calculated successfully", getName(), value); return ChapterResult.success(value);
161
51
212
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/saga/src/main/java/com/iluwatar/saga/orchestration/WithdrawMoneyService.java
WithdrawMoneyService
process
class WithdrawMoneyService extends Service<String> { @Override public String getName() { return "withdrawing Money"; } @Override public ChapterResult<String> process(String value) {<FILL_FUNCTION_BODY>} }
if (value.equals("bad_order") || value.equals("crashed_order")) { LOGGER.info("The chapter '{}' has been started. But the exception has been raised." + "The rollback is about to start", getName(), value); return ChapterResult.failure(value); } return super.process(value)...
70
91
161
<methods>public non-sealed void <init>() ,public abstract java.lang.String getName() ,public ChapterResult<java.lang.String> process(java.lang.String) ,public ChapterResult<java.lang.String> rollback(java.lang.String) <variables>protected static final Logger LOGGER
iluwatar_java-design-patterns
java-design-patterns/separated-interface/src/main/java/com/iluwatar/separatedinterface/App.java
App
main
class App { public static final double PRODUCT_COST = 50.0; /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
//Create the invoice generator with product cost as 50 and foreign product tax var internationalProductInvoice = new InvoiceGenerator(PRODUCT_COST, new ForeignTaxCalculator()); LOGGER.info("Foreign Tax applied: {}", "" + internationalProductInvoice.getAmountWithTax()); //Create the invoice gen...
75
149
224
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/serialized-entity/src/main/java/com/iluwatar/serializedentity/App.java
App
main
class App { private static final String DB_URL = "jdbc:h2:mem:testdb"; private App() { } /** * Program entry point. * @param args command line args. * @throws IOException if any * @throws ClassNotFoundException if any */ public static void main(String[] args) throws IOException, ClassNotFoun...
final var dataSource = createDataSource(); deleteSchema(dataSource); createSchema(dataSource); // Initializing Country Object China final var China = new Country( 86, "China", "Asia", "Chinese" ); // Initializing Country Object UnitedArabEm...
333
413
746
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/serialized-entity/src/main/java/com/iluwatar/serializedentity/CountrySchemaSql.java
CountrySchemaSql
selectCountry
class CountrySchemaSql implements CountryDao { public static final String CREATE_SCHEMA_SQL = "CREATE TABLE IF NOT EXISTS WORLD (ID INT PRIMARY KEY, COUNTRY BLOB)"; public static final String DELETE_SCHEMA_SQL = "DROP TABLE WORLD IF EXISTS"; private Country country; private DataSource dataSource; /** * ...
var sql = "SELECT ID, COUNTRY FROM WORLD WHERE ID = ?"; try (var connection = dataSource.getConnection(); var preparedStatement = connection.prepareStatement(sql)) { preparedStatement.setInt(1, country.getCode()); try (ResultSet rs = preparedStatement.executeQuery()) { if (rs.nex...
563
233
796
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/servant/src/main/java/com/iluwatar/servant/App.java
App
scenario
class App { private static final Servant jenkins = new Servant("Jenkins"); private static final Servant travis = new Servant("Travis"); /** * Program entry point. */ public static void main(String[] args) { scenario(jenkins, 1); scenario(travis, 0); } /** * Can add a List with enum Actio...
var k = new King(); var q = new Queen(); var guests = List.of(k, q); // feed servant.feed(k); servant.feed(q); // serve drinks servant.giveWine(k); servant.giveWine(q); // compliment servant.giveCompliments(guests.get(compliment)); // outcome of the night guests.f...
144
195
339
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/servant/src/main/java/com/iluwatar/servant/King.java
King
changeMood
class King implements Royalty { private boolean isDrunk; private boolean isHungry = true; private boolean isHappy; private boolean complimentReceived; @Override public void getFed() { isHungry = false; } @Override public void getDrink() { isDrunk = true; } public void receiveCompliment...
if (!isHungry && isDrunk) { isHappy = true; } if (complimentReceived) { isHappy = false; }
166
47
213
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/servant/src/main/java/com/iluwatar/servant/Queen.java
Queen
changeMood
class Queen implements Royalty { private boolean isDrunk = true; private boolean isHungry; private boolean isHappy; private boolean isFlirty = true; private boolean complimentReceived; @Override public void getFed() { isHungry = false; } @Override public void getDrink() { isDrunk = true; ...
if (complimentReceived && isFlirty && isDrunk && !isHungry) { isHappy = true; }
204
37
241
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/server-session/src/main/java/com/iluwatar/sessionserver/App.java
App
sessionExpirationTask
class App { // Map to store session data (simulated using a HashMap) private static Map<String, Integer> sessions = new HashMap<>(); private static Map<String, Instant> sessionCreationTimes = new HashMap<>(); private static final long SESSION_EXPIRATION_TIME = 10000; /** * Main entry point. * @param a...
new Thread(() -> { while (true) { try { LOGGER.info("Session expiration checker started..."); Thread.sleep(SESSION_EXPIRATION_TIME); // Sleep for expiration time Instant currentTime = Instant.now(); synchronized (sessions) { synchronized (sessionCre...
300
267
567
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/server-session/src/main/java/com/iluwatar/sessionserver/LoginHandler.java
LoginHandler
handle
class LoginHandler implements HttpHandler { private Map<String, Integer> sessions; private Map<String, Instant> sessionCreationTimes; public LoginHandler(Map<String, Integer> sessions, Map<String, Instant> sessionCreationTimes) { this.sessions = sessions; this.sessionCreationTimes = sessionCreationTimes...
// Generate session ID String sessionId = UUID.randomUUID().toString(); // Store session data (simulated) int newUser = sessions.size() + 1; sessions.put(sessionId, newUser); sessionCreationTimes.put(sessionId, Instant.now()); LOGGER.info("User " + newUser + " created at time " + sessionCr...
120
262
382
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/server-session/src/main/java/com/iluwatar/sessionserver/LogoutHandler.java
LogoutHandler
handle
class LogoutHandler implements HttpHandler { private Map<String, Integer> sessions; private Map<String, Instant> sessionCreationTimes; public LogoutHandler(Map<String, Integer> sessions, Map<String, Instant> sessionCreationTimes) { this.sessions = sessions; this.sessionCreationTimes = sessionCreationTim...
// Get session ID from cookie String sessionId = exchange.getRequestHeaders().getFirst("Cookie").replace("sessionID=", ""); String currentSessionId = sessions.get(sessionId) == null ? null : sessionId; // Send response String response = ""; if (currentSessionId == null) { response += "S...
122
308
430
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/app/App.java
App
initData
class App { public static final String BOOK_OF_IDORES = "Book of Idores"; /** * Program entry point. * * @param args command line args */ public static void main(String[] args) { // populate the in-memory database initData(); // query the data using the service queryData(); } /**...
// spells var spell1 = new Spell("Ice dart"); var spell2 = new Spell("Invisibility"); var spell3 = new Spell("Stun bolt"); var spell4 = new Spell("Confusion"); var spell5 = new Spell("Darkness"); var spell6 = new Spell("Fireball"); var spell7 = new Spell("Enchant weapon"); var spell...
507
1,489
1,996
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/common/DaoBaseImpl.java
DaoBaseImpl
merge
class DaoBaseImpl<E extends BaseEntity> implements Dao<E> { @SuppressWarnings("unchecked") protected Class<E> persistentClass = (Class<E>) ((ParameterizedType) getClass() .getGenericSuperclass()).getActualTypeArguments()[0]; /* * Making this getSessionFactory() instead of getSession() so that it is the...
Transaction tx = null; E result = null; try (var session = getSessionFactory().openSession()) { tx = session.beginTransaction(); result = (E) session.merge(entity); tx.commit(); } catch (Exception e) { if (tx != null) { tx.rollback(); } throw e; } ret...
773
103
876
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/hibernate/HibernateUtil.java
HibernateUtil
getSessionFactory
class HibernateUtil { /** * The cached session factory. */ private static volatile SessionFactory sessionFactory; private HibernateUtil() { } /** * Create the current session factory instance, create a new one when there is none yet. * * @return The session factory */ public static sync...
if (sessionFactory == null) { try { sessionFactory = new Configuration() .addAnnotatedClass(Wizard.class) .addAnnotatedClass(Spellbook.class) .addAnnotatedClass(Spell.class) .setProperty("hibernate.dialect", "org.hibernate.dialect.H2Dialect") ...
183
244
427
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/magic/MagicServiceImpl.java
MagicServiceImpl
findWizardsWithSpell
class MagicServiceImpl implements MagicService { private final WizardDao wizardDao; private final SpellbookDao spellbookDao; private final SpellDao spellDao; /** * Constructor. */ public MagicServiceImpl(WizardDao wizardDao, SpellbookDao spellbookDao, SpellDao spellDao) { this.wizardDao = wizardDa...
var spell = spellDao.findByName(name); var spellbook = spell.getSpellbook(); return new ArrayList<>(spellbook.getWizards());
344
47
391
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/spell/SpellDaoImpl.java
SpellDaoImpl
findByName
class SpellDaoImpl extends DaoBaseImpl<Spell> implements SpellDao { @Override public Spell findByName(String name) {<FILL_FUNCTION_BODY>} }
Transaction tx = null; Spell result; try (var session = getSessionFactory().openSession()) { tx = session.beginTransaction(); CriteriaBuilder criteriaBuilder = session.getCriteriaBuilder(); CriteriaQuery<Spell> builderQuery = criteriaBuilder.createQuery(Spell.class); Root<Spell> roo...
54
197
251
<methods>public non-sealed void <init>() ,public void delete(com.iluwatar.servicelayer.spell.Spell) ,public com.iluwatar.servicelayer.spell.Spell find(java.lang.Long) ,public List<com.iluwatar.servicelayer.spell.Spell> findAll() ,public com.iluwatar.servicelayer.spell.Spell merge(com.iluwatar.servicelayer.spell.Spell) ...
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/spellbook/SpellbookDaoImpl.java
SpellbookDaoImpl
findByName
class SpellbookDaoImpl extends DaoBaseImpl<Spellbook> implements SpellbookDao { @Override public Spellbook findByName(String name) {<FILL_FUNCTION_BODY>} }
Transaction tx = null; Spellbook result; try (var session = getSessionFactory().openSession()) { tx = session.beginTransaction(); CriteriaBuilder criteriaBuilder = session.getCriteriaBuilder(); CriteriaQuery<Spellbook> builderQuery = criteriaBuilder.createQuery(Spellbook.class); Roo...
59
203
262
<methods>public non-sealed void <init>() ,public void delete(com.iluwatar.servicelayer.spellbook.Spellbook) ,public com.iluwatar.servicelayer.spellbook.Spellbook find(java.lang.Long) ,public List<com.iluwatar.servicelayer.spellbook.Spellbook> findAll() ,public com.iluwatar.servicelayer.spellbook.Spellbook merge(com.ilu...
iluwatar_java-design-patterns
java-design-patterns/service-layer/src/main/java/com/iluwatar/servicelayer/wizard/WizardDaoImpl.java
WizardDaoImpl
findByName
class WizardDaoImpl extends DaoBaseImpl<Wizard> implements WizardDao { @Override public Wizard findByName(String name) {<FILL_FUNCTION_BODY>} }
Transaction tx = null; Wizard result; try (var session = getSessionFactory().openSession()) { tx = session.beginTransaction(); CriteriaBuilder criteriaBuilder = session.getCriteriaBuilder(); CriteriaQuery<Wizard> builderQuery = criteriaBuilder.createQuery(Wizard.class); Root<Wizard>...
54
197
251
<methods>public non-sealed void <init>() ,public void delete(com.iluwatar.servicelayer.wizard.Wizard) ,public com.iluwatar.servicelayer.wizard.Wizard find(java.lang.Long) ,public List<com.iluwatar.servicelayer.wizard.Wizard> findAll() ,public com.iluwatar.servicelayer.wizard.Wizard merge(com.iluwatar.servicelayer.wizar...
iluwatar_java-design-patterns
java-design-patterns/service-locator/src/main/java/com/iluwatar/servicelocator/App.java
App
main
class App { public static final String JNDI_SERVICE_A = "jndi/serviceA"; public static final String JNDI_SERVICE_B = "jndi/serviceB"; /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var service = ServiceLocator.getService(JNDI_SERVICE_A); service.execute(); service = ServiceLocator.getService(JNDI_SERVICE_B); service.execute(); service = ServiceLocator.getService(JNDI_SERVICE_A); service.execute(); service = ServiceLocator.getService(JNDI_SERVICE_A); service.execut...
103
108
211
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-locator/src/main/java/com/iluwatar/servicelocator/InitContext.java
InitContext
lookup
class InitContext { /** * Perform the lookup based on the service name. The returned object will need to be casted into a * {@link Service} * * @param serviceName a string * @return an {@link Object} */ public Object lookup(String serviceName) {<FILL_FUNCTION_BODY>} }
if (serviceName.equals("jndi/serviceA")) { LOGGER.info("Looking up service A and creating new service for A"); return new ServiceImpl("jndi/serviceA"); } else if (serviceName.equals("jndi/serviceB")) { LOGGER.info("Looking up service B and creating new service for B"); return new Servic...
90
116
206
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceCache.java
ServiceCache
getService
class ServiceCache { private final Map<String, Service> serviceCache; public ServiceCache() { serviceCache = new HashMap<>(); } /** * Get the service from the cache. null if no service is found matching the name * * @param serviceName a string * @return {@link Service} */ public Service ...
if (serviceCache.containsKey(serviceName)) { var cachedService = serviceCache.get(serviceName); var name = cachedService.getName(); var id = cachedService.getId(); LOGGER.info("(cache call) Fetched service {}({}) from cache... !", name, id); return cachedService; } return null...
177
93
270
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceImpl.java
ServiceImpl
execute
class ServiceImpl implements Service { private final String serviceName; private final int id; /** * Constructor. */ public ServiceImpl(String serviceName) { // set the service name this.serviceName = serviceName; // Generate a random id to this service object this.id = (int) Math.floor...
LOGGER.info("Service {} is now executing with id {}", getName(), getId());
176
25
201
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-locator/src/main/java/com/iluwatar/servicelocator/ServiceLocator.java
ServiceLocator
getService
class ServiceLocator { private static final ServiceCache serviceCache = new ServiceCache(); private ServiceLocator() { } /** * Fetch the service with the name param from the cache first, if no service is found, lookup the * service from the {@link InitContext} and then add the newly created service int...
var serviceObj = serviceCache.getService(serviceJndiName); if (serviceObj != null) { return serviceObj; } else { /* * If we are unable to retrieve anything from cache, then lookup the service and add it in the * cache map */ var ctx = new InitContext(); serviceO...
147
147
294
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-to-worker/src/main/java/com/iluwatar/servicetoworker/App.java
App
main
class App { /** * Program entry point. * * @param args command line args */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
// create model, view and controller var giant1 = new GiantModel("giant1", Health.HEALTHY, Fatigue.ALERT, Nourishment.SATURATED); var giant2 = new GiantModel("giant2", Health.DEAD, Fatigue.SLEEPING, Nourishment.STARVING); var action1 = new Action(giant1); var action2 = new Action(giant2); var v...
56
322
378
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/service-to-worker/src/main/java/com/iluwatar/servicetoworker/GiantModel.java
GiantModel
toString
class GiantModel { private final com.iluwatar.model.view.controller.GiantModel model; @Getter private final String name; /** * Instantiates a new Giant model. * * @param name the name * @param health the health * @param fatigue the fatigue * @param nourishment the nourishment...
return String .format("Giant %s, The giant looks %s, %s and %s.", name, model.getHealth(), model.getFatigue(), model.getNourishment());
474
52
526
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/App.java
App
main
class App { /** * Program main entry point. * * @param args program runtime arguments */ public static void main(String[] args) {<FILL_FUNCTION_BODY>} }
var data1 = new Data(1, "data1", Data.DataType.TYPE_1); var data2 = new Data(2, "data2", Data.DataType.TYPE_2); var data3 = new Data(3, "data3", Data.DataType.TYPE_3); var data4 = new Data(4, "data4", Data.DataType.TYPE_1); var shard1 = new Shard(1); var shard2 = new Shard(2); var shard3 ...
58
546
604
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/Data.java
Data
toString
class Data { private int key; private String value; private DataType type; /** * Constructor of Data class. * @param key data key * @param value data vlue * @param type data type */ public Data(final int key, final String value, final DataType type) { this.key = key; this.value = va...
return "Data {" + "key=" + key + ", value='" + value + '\'' + ", type=" + type + '}';
288
41
329
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/HashShardManager.java
HashShardManager
allocateShard
class HashShardManager extends ShardManager { @Override public int storeData(Data data) { var shardId = allocateShard(data); var shard = shardMap.get(shardId); shard.storeData(data); LOGGER.info(data.toString() + " is stored in Shard " + shardId); return shardId; } @Override protected in...
var shardCount = shardMap.size(); var hash = data.getKey() % shardCount; return hash == 0 ? hash + shardCount : hash;
134
46
180
<methods>public void <init>() ,public boolean addNewShard(com.iluwatar.sharding.Shard) ,public com.iluwatar.sharding.Shard getShardById(int) ,public boolean removeShardById(int) ,public abstract int storeData(com.iluwatar.sharding.Data) <variables>protected Map<java.lang.Integer,com.iluwatar.sharding.Shard> shardMap
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/LookupShardManager.java
LookupShardManager
allocateShard
class LookupShardManager extends ShardManager { private final Map<Integer, Integer> lookupMap = new HashMap<>(); @Override public int storeData(Data data) { var shardId = allocateShard(data); lookupMap.put(data.getKey(), shardId); var shard = shardMap.get(shardId); shard.storeData(data); LOG...
var key = data.getKey(); if (lookupMap.containsKey(key)) { return lookupMap.get(key); } else { var shardCount = shardMap.size(); return new SecureRandom().nextInt(shardCount - 1) + 1; }
170
79
249
<methods>public void <init>() ,public boolean addNewShard(com.iluwatar.sharding.Shard) ,public com.iluwatar.sharding.Shard getShardById(int) ,public boolean removeShardById(int) ,public abstract int storeData(com.iluwatar.sharding.Data) <variables>protected Map<java.lang.Integer,com.iluwatar.sharding.Shard> shardMap
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/RangeShardManager.java
RangeShardManager
storeData
class RangeShardManager extends ShardManager { @Override public int storeData(Data data) {<FILL_FUNCTION_BODY>} @Override protected int allocateShard(Data data) { var type = data.getType(); return switch (type) { case TYPE_1 -> 1; case TYPE_2 -> 2; case TYPE_3 -> 3; default -> ...
var shardId = allocateShard(data); var shard = shardMap.get(shardId); shard.storeData(data); LOGGER.info(data.toString() + " is stored in Shard " + shardId); return shardId;
122
74
196
<methods>public void <init>() ,public boolean addNewShard(com.iluwatar.sharding.Shard) ,public com.iluwatar.sharding.Shard getShardById(int) ,public boolean removeShardById(int) ,public abstract int storeData(com.iluwatar.sharding.Data) <variables>protected Map<java.lang.Integer,com.iluwatar.sharding.Shard> shardMap
iluwatar_java-design-patterns
java-design-patterns/sharding/src/main/java/com/iluwatar/sharding/ShardManager.java
ShardManager
removeShardById
class ShardManager { protected Map<Integer, Shard> shardMap; public ShardManager() { shardMap = new HashMap<>(); } /** * Add a provided shard instance to shardMap. * * @param shard new shard instance. * @return {@code true} if succeed to add the new instance. * {@code false} if the...
if (shardMap.containsKey(shardId)) { shardMap.remove(shardId); return true; } else { return false; }
484
49
533
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/single-table-inheritance/src/main/java/com/iluwatar/SingleTableInheritance.java
SingleTableInheritance
run
class SingleTableInheritance implements CommandLineRunner { //Autowiring the VehicleService class to execute the business logic methods private final VehicleService vehicleService; /** * The entry point of the Spring Boot Application. * * @param args program runtime arguments */ public static void...
Logger log = LoggerFactory.getLogger(SingleTableInheritance.class); log.info("Saving Vehicles :- "); // Saving Car to DB as a Vehicle Vehicle vehicle1 = new Car("Tesla", "Model S", 4, 825); Vehicle car1 = vehicleService.saveVehicle(vehicle1); log.info("Vehicle 1 saved : {}", car1); // S...
176
437
613
<no_super_class>
iluwatar_java-design-patterns
java-design-patterns/single-table-inheritance/src/main/java/com/iluwatar/entity/Freighter.java
Freighter
toString
class Freighter extends TransportVehicle { private double flightLength; public Freighter(String manufacturer, String model, int loadCapacity, double flightLength) { super(manufacturer, model, loadCapacity); this.flightLength = flightLength; } // Overridden the toString method to specify the Vehicle o...
return "Freighter{ " + super.toString() + " ," + "flightLength=" + flightLength + '}';
114
45
159
<methods><variables>private int loadCapacity
iluwatar_java-design-patterns
java-design-patterns/single-table-inheritance/src/main/java/com/iluwatar/entity/Truck.java
Truck
toString
class Truck extends TransportVehicle { private int towingCapacity; public Truck(String manufacturer, String model, int loadCapacity, int towingCapacity) { super(manufacturer, model, loadCapacity); this.towingCapacity = towingCapacity; } // Overridden the toString method to specify the Vehicle object ...
return "Truck{ " + super.toString() + ", " + "towingCapacity=" + towingCapacity + '}';
120
47
167
<methods><variables>private int loadCapacity