Add Threads ReadWriteLock example

Artem Pronchakov · Artem Pronchakov · commit 8435711dfd1e · 2014-12-22T01:17:11.000+03:00
diff --git a/.idea/modules.xml b/.idea/modules.xml
diff --git a/Threads/ReadWriteLock/ReadWriteLock.iml b/Threads/ReadWriteLock/ReadWriteLock.iml
@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>
diff --git a/Threads/ReadWriteLock/src/edu/javacourse/threads/ReadWriteLockExample.java b/Threads/ReadWriteLock/src/edu/javacourse/threads/ReadWriteLockExample.java
@@ -0,0 +1,31 @@
+package edu.javacourse.threads;
+
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+/**
+ * @author Artem Pronchakov | email/xmpp: artem.pronchakov@calisto.email
+ */
+public class ReadWriteLockExample {
+
+    public static void main(String[] args) {
+
+        ReadWriteLock lock = new ReentrantReadWriteLock();
+
+        Thread reader1 = new Thread(new Reader(lock), "reader1");
+        Thread reader2 = new Thread(new Reader(lock), "reader2");
+        Thread reader3 = new Thread(new Reader(lock), "reader3");
+
+        Thread writer1 = new Thread(new Writer(lock), "writer1");
+        Thread writer2 = new Thread(new Writer(lock), "writer2");
+
+        reader1.start();
+        reader2.start();
+        reader3.start();
+
+        writer1.start();
+        writer2.start();
+
+    }
+
+}
diff --git a/Threads/ReadWriteLock/src/edu/javacourse/threads/Reader.java b/Threads/ReadWriteLock/src/edu/javacourse/threads/Reader.java
@@ -0,0 +1,35 @@
+package edu.javacourse.threads;
+
+import java.util.Random;
+import java.util.concurrent.locks.ReadWriteLock;
+
+/**
+ * @author Artem Pronchakov | email/xmpp: artem.pronchakov@calisto.email
+ */
+public class Reader implements Runnable {
+
+    private ReadWriteLock lock;
+
+    public Reader(ReadWriteLock lock) {
+        this.lock = lock;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            lock.readLock().lock();
+            System.out.println("Thread " + Thread.currentThread().getName() + " got lock");
+
+            System.out.println("\tThread " + Thread.currentThread().getName() + ": Shared data: " + SharedData.i);
+
+            try {
+                Thread.sleep(new Random().nextInt(5));
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+
+            System.out.println("Thread " + Thread.currentThread().getName() + " releasing read lock");
+            lock.readLock().unlock();
+        }
+    }
+}
diff --git a/Threads/ReadWriteLock/src/edu/javacourse/threads/SharedData.java b/Threads/ReadWriteLock/src/edu/javacourse/threads/SharedData.java
@@ -0,0 +1,8 @@
+package edu.javacourse.threads;
+
+/**
+ * @author Artem Pronchakov | email/xmpp: artem.pronchakov@calisto.email
+ */
+public class SharedData {
+    public static int i = 0;
+}
diff --git a/Threads/ReadWriteLock/src/edu/javacourse/threads/Writer.java b/Threads/ReadWriteLock/src/edu/javacourse/threads/Writer.java
@@ -0,0 +1,39 @@
+package edu.javacourse.threads;
+
+import java.util.Random;
+import java.util.concurrent.locks.ReadWriteLock;
+
+/**
+ * @author Artem Pronchakov | email/xmpp: artem.pronchakov@calisto.email
+ */
+public class Writer implements Runnable {
+
+    private ReadWriteLock lock;
+
+    public Writer(ReadWriteLock lock) {
+        this.lock = lock;
+    }
+
+    @Override
+    public void run() {
+        while (true) {
+            lock.writeLock().lock();
+            System.out.println("\t\t\t\t===================================================");
+            System.out.println("\t\t\t\tThread " + Thread.currentThread().getName() + " got lock");
+
+            int newI = SharedData.i + 1;
+            System.out.println("\t\t\t\t\tThread " + Thread.currentThread().getName() + ": Shared data changing to: " + newI);
+            SharedData.i = newI;
+
+            System.out.println("\t\t\t\tThread " + Thread.currentThread().getName() + " releasing write lock");
+            System.out.println("\t\t\t\t===================================================");
+            lock.writeLock().unlock();
+
+            try {
+                Thread.sleep(new Random().nextInt(40));
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}
