Day-17 : Hacker Police Game.

Author: kumarcodes

src/main/java/com/java8/StreamReuse.java

@@ -0,0 +1,18 @@
+package com.java8;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class StreamReuse {
+    //We can't resue stream.
+    public static void main(String[] args) {
+        List<String> nameList = Arrays.asList("alice", "neena", "meena", "rohan", "neema");
+        Stream<String> stringStream = nameList.stream();
+        //Consumption 1
+        stringStream.forEach(System.out::println);
+        //Consumption 2 will throw IllegalStateException stating stream has already been operated upon or closed
+        // long length = stringStream.count();
+
+    }
+}

src/main/java/com/multithreading/HackerPolice.java

@@ -0,0 +1,102 @@
+package com.multithreading;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Random;
+
+public class HackerPolice {
+    private static final int MAX_PASSWORD = 9999;
+
+    public static void main(String[] args) {
+        Random random = new Random();
+        Vault vault = new Vault(random.nextInt(MAX_PASSWORD));
+        List<Thread> threads = new ArrayList<>();
+        threads.add(new AscendingHackerThread(vault));
+        threads.add(new DescendingHackerThread(vault));
+        threads.add(new PoliceThread());
+        for (Thread thread : threads) {
+            thread.start();
+        }
+
+    }
+
+    private static class Vault {
+        private int password;
+
+        public Vault(int password) {
+            this.password = password;
+        }
+
+
+        public boolean isCorrectPassword(int guess) {
+            try {
+                Thread.sleep(5);
+            } catch (InterruptedException e) {
+            }
+            return this.password == guess;
+        }
+    }
+
+    private static abstract class HackerThread extends Thread {
+        protected Vault vault;
+
+        public HackerThread(Vault vault) {
+            this.vault = vault;
+            this.setName(this.getClass().getSimpleName());
+            this.setPriority(Thread.MAX_PRIORITY);
+        }
+
+        @Override
+        public void start() {
+            System.out.println("Starting thread" + this.getName());
+            super.start();
+        }
+    }
+
+    private static class AscendingHackerThread extends HackerThread {
+        public AscendingHackerThread(Vault vault) {
+            super(vault);
+        }
+
+        @Override
+        public void run() {
+            for (int guess = 0; guess < MAX_PASSWORD; guess++) {
+                if (vault.isCorrectPassword(guess)) {
+                    System.out.println(this.getName() + " get the password " + guess);
+                    System.exit(0);
+                }
+            }
+        }
+    }
+
+    private static class DescendingHackerThread extends HackerThread {
+        public DescendingHackerThread(Vault vault) {
+            super(vault);
+        }
+
+        @Override
+        public void run() {
+            for (int guess = MAX_PASSWORD; guess >= 0; guess--) {
+                if (vault.isCorrectPassword(guess)) {
+                    System.out.println(this.getName() + " get the password " + guess);
+                    System.exit(0);
+                }
+            }
+        }
+    }
+
+    private static class PoliceThread extends Thread {
+        @Override
+        public void run() {
+            for (int i = 10; i > 0; i--) {
+                try {
+                    Thread.sleep(1000);
+                } catch (InterruptedException e) {
+                }
+                System.out.println(i);
+            }
+            System.out.println("Game over for you hackers!");
+            System.exit(0);
+        }
+    }
+}

src/main/java/com/multithreading/ThreadCreation.java

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+package com.multithreading;
+
+public class ThreadCreation {
+    public static void main(String[] args) throws InterruptedException {
+        Thread thread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                System.out.println("Thread name inside run method: " + Thread.currentThread().getName());
+                System.out.println("Priority of this thread is: " + Thread.currentThread().getPriority());
+            }
+        });
+        thread.setPriority(Thread.MAX_PRIORITY);
+        thread.setName("New Worker Thread");
+        System.out.println("Thread Name before start: " + Thread.currentThread().getName());
+        thread.start();
+        System.out.println("Thread name after start: " + Thread.currentThread().getName());
+        Thread.sleep(1000);
+    }
+}