objList.stream().filter(obj -> obj.method() == value1).forEach(obj -> ...);

Week 7: Enum, Generic Type, Streams, write to file, class diagram/10B. Print North Routes

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+The program assumes that we have a 'Route' class available, with the following 'get' methods needed for the task:
+- getDirection(), which returns the direction of the route. 
+  The return value is an enum of type 'CardinalDirection', with four possible values (NORTH, SOUTH, EAST, and WEST).
+- getLength(), which returns the route's length as a floating-point number.
+
+
+
+
+Write a class 'method'
+public static void printNorthRoutes(ArrayList<Route> routes)
+
+which receives a list of Route objects as a parameter. 
+The method prints all the routes whose direction is north. 
+Use the Route class's toString method for printing.
+
+
+
+
+
+import java.util.Random;
+import java.util.ArrayList;
+import java.util.Collections;
+
+public class Test{
+    public static void main(String[] args){
+        final Random r = new Random();
+        
+     
+        ArrayList<Route> routes = new ArrayList<>();
+        // r.nextInt(3) => from 0 (incl) to 3 (excl)
+        int m = r.nextInt(3) + 2;
+        for (int i = 0; i < m; i++) {
+            routes.add(new Route(r.nextInt(100), CardinalDirection.NORTH));
+        }
+        
+        m = r.nextInt(5) + 5;
+        CardinalDirection[] nonNorth = {CardinalDirection.SOUTH, CardinalDirection.EAST, CardinalDirection.WEST};
+        for (int i = 0; i < m; i++) {
+            routes.add(new Route(r.nextInt(100), nonNorth[r.nextInt(3)]));
+        }
+        
+        Collections.shuffle(routes, r);
+        
+        System.out.println("All routes:");
+        routes.stream().forEach(re -> System.out.println(re));
+        
+        System.out.println("North routes:");
+        printNorthRoutes(routes);
+       
+    }
+
+
+    //ADD
+    public static void printNorthRoutes(ArrayList<Route> routes) {
+         // print
+         routes.stream().filter(route -> route.getDirection() == CardinalDirection.NORTH).forEach(route -> System.out.println(route));
+         // store in a new ArrayList
+         // ArrayList<Route> northRoutes = routes.stream().filter(route -> route.getDirection() == CardinalDirection.NORTH).collect(Collectors.toCollection(ArrayList::new));
+         // return northRoutes;
+    }
+
+
+
+
+
+
+}
+
+
+
+
+
+
+
+
+class Route {
+    private double length;
+    private CardinalDirection direction;
+    
+    public Route(double length, CardinalDirection direction) {
+        this.length = length;
+        this.direction = direction;
+    }
+
+
+
+
+    public double getLength() {
+        return length;
+    }
+
+    public void setLength(double length) {
+        this.length = length;
+    }
+
+
+
+
+    public CardinalDirection getDirection() {
+        return direction;
+    }
+
+    public void setDirection(CardinalDirection direction) {
+        this.direction = direction;
+    } 
+
+
+
+    
+    public String toString() {
+        return "Direction: " + direction + ", length: " + length;
+    }
+}
+
+
+
+enum CardinalDirection {
+    NORTH, SOUTH, EAST, WEST
+}
+
+
+
+
+
+
+
+
+
+
+
+All routes:
+Direction: SOUTH, length: 16.0
+Direction: NORTH, length: 77.0
+Direction: NORTH, length: 95.0
+Direction: WEST, length: 7.0
+Direction: SOUTH, length: 33.0
+Direction: NORTH, length: 96.0
+Direction: WEST, length: 90.0
+Direction: SOUTH, length: 29.0
+Direction: SOUTH, length: 10.0
+Direction: WEST, length: 7.0
+Direction: EAST, length: 7.0
+Direction: WEST, length: 79.0
+Direction: NORTH, length: 19.0
+
+
+North routes:
+Direction: NORTH, length: 77.0
+Direction: NORTH, length: 95.0
+Direction: NORTH, length: 96.0
+Direction: NORTH, length: 19.0
+
+
+
+