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[add] add some examples of concurrency,especially BlockingQueue · lzleen/java-learning@50a4d82 · GitHub

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forked from brianway/java-learning

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[add] add some examples of concurrency,especially BlockingQueue
1 parent c017048 commit 50a4d82

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‎java-multithread/src/main/java/com/brianway/learning/java/concurrent/CloseResource.java‎

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package com.brianway.learning.java.concurrent;
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import java.io.InputStream;
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import java.net.ServerSocket;
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import java.net.Socket;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.TimeUnit;
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/**
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* Interrupting a blocked task by closing the underlying resource.
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* {RunByHand}
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*/
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public class CloseResource {
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public static void main(String[] args) throws Exception {
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ExecutorService exec = Executors.newCachedThreadPool();
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ServerSocket server = new ServerSocket(8080);
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InputStream socketInput =
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new Socket("localhost", 8080).getInputStream();
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exec.execute(new IOBlocked(socketInput));
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exec.execute(new IOBlocked(System.in));
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TimeUnit.MILLISECONDS.sleep(100);
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System.out.println("Shutting down all threads");
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exec.shutdownNow();
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TimeUnit.SECONDS.sleep(1);
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System.out.println("Closing " + socketInput.getClass().getName());
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socketInput.close(); // Releases blocked thread
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TimeUnit.SECONDS.sleep(1);
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System.out.println("Closing " + System.in.getClass().getName());
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System.in.close(); // Releases blocked thread
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}
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}
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/* Output: (85% match)
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Waiting for read():
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Waiting for read():
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Shutting down all threads
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Closing java.net.SocketInputStream
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Interrupted from blocked I/O
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Exiting IOBlocked.run()
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Closing java.io.BufferedInputStream
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Exiting IOBlocked.run()
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*///:~

‎java-multithread/src/main/java/com/brianway/learning/java/concurrent/Interrupting.java‎

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package com.brianway.learning.java.concurrent;
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import java.io.IOException;
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import java.io.InputStream;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.Future;
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import java.util.concurrent.TimeUnit;
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/**
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* Interrupting a blocked thread.
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*
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*
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*/
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public class Interrupting {
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private static ExecutorService exec =
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Executors.newCachedThreadPool();
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static void test(Runnable r) throws InterruptedException {
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Future<?> f = exec.submit(r);
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TimeUnit.MILLISECONDS.sleep(100);
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System.out.println("Interrupting " + r.getClass().getSimpleName());
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f.cancel(true); // Interrupts if running
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System.out.println("Interrupt sent to " + r.getClass().getSimpleName());
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}
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public static void main(String[] args) throws Exception {
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test(new SleepBlocked());
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test(new IOBlocked(System.in));
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test(new SynchronizedBlocked());
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TimeUnit.SECONDS.sleep(3);
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System.out.println("Aborting with System.exit(0)");
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System.exit(0); // ... since last 2 interrupts failed
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}
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}
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/**
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* 可中断的阻塞示例
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*/
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class SleepBlocked implements Runnable {
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public void run() {
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try {
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TimeUnit.SECONDS.sleep(100);
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} catch (InterruptedException e) {
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System.out.println("InterruptedException");
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}
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System.out.println("Exiting SleepBlocked.run()");
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}
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}
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class IOBlocked implements Runnable {
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private InputStream in;
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public IOBlocked(InputStream is) {
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in = is;
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}
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public void run() {
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try {
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System.out.println("Waiting for read():");
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in.read();
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} catch (IOException e) {
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if (Thread.currentThread().isInterrupted()) {
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System.out.println("Interrupted from blocked I/O");
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} else {
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throw new RuntimeException(e);
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}
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}
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System.out.println("Exiting IOBlocked.run()");
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}
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}
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class SynchronizedBlocked implements Runnable {
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public synchronized void f() {
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while (true) // Never releases lock
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Thread.yield();
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}
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public SynchronizedBlocked() {
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new Thread() {
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public void run() {
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f(); // Lock acquired by this thread
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}
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}.start();
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}
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public void run() {
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System.out.println("Trying to call f()");
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f();
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System.out.println("Exiting SynchronizedBlocked.run()");
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}
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}
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/* Output: (95% match)
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Interrupting SleepBlocked
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Interrupt sent to SleepBlocked
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InterruptedException
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Exiting SleepBlocked.run()
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Waiting for read():
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Interrupting IOBlocked
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Interrupt sent to IOBlocked
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Trying to call f()
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Interrupting SynchronizedBlocked
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Interrupt sent to SynchronizedBlocked
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Aborting with System.exit(0)
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*///:~

‎java-multithread/src/main/java/com/brianway/learning/java/concurrent/InterruptingIdiom.java‎

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package com.brianway.learning.java.concurrent;
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import java.util.concurrent.TimeUnit;
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/**
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* General idiom for interrupting a task.
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* {Args: 1100}
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*/
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public class InterruptingIdiom {
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public static void main(String[] args) throws Exception {
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if (args.length != 1) {
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System.out.println("usage: java InterruptingIdiom delay-in-mS");
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System.exit(1);
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}
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Thread t = new Thread(new Blocked3());
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t.start();
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TimeUnit.MILLISECONDS.sleep(new Integer(args[0]));
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t.interrupt();
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}
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}
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class NeedsCleanup {
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private final int id;
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public NeedsCleanup(int ident) {
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id = ident;
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System.out.println("NeedsCleanup " + id);
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}
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public void cleanup() {
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System.out.println("Cleaning up " + id);
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}
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}
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class Blocked3 implements Runnable {
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private volatile double d = 0.0;
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public void run() {
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try {
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while (!Thread.interrupted()) {
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// point1
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NeedsCleanup n1 = new NeedsCleanup(1);
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// Start try-finally immediately after definition
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// of n1, to guarantee proper cleanup of n1:
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try {
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System.out.println("Sleeping");
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TimeUnit.SECONDS.sleep(1);
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// point2
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NeedsCleanup n2 = new NeedsCleanup(2);
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// Guarantee proper cleanup of n2:
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try {
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System.out.println("Calculating");
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// A time-consuming, non-blocking operation:
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for (int i = 1; i < 2500000; i++)
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d = d + (Math.PI + Math.E) / d;
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System.out.println("Finished time-consuming operation");
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} finally {
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n2.cleanup();
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}
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} finally {
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n1.cleanup();
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}
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}
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System.out.println("Exiting via while() test");
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} catch (InterruptedException e) {
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System.out.println("Exiting via InterruptedException");
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}
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}
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}
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/* Output: (Sample)
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NeedsCleanup 1
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Sleeping
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NeedsCleanup 2
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Calculating
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Finished time-consuming operation
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Cleaning up 2
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Cleaning up 1
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NeedsCleanup 1
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Sleeping
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Cleaning up 1
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Exiting via InterruptedException
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*///:~

‎java-multithread/src/main/java/com/brianway/learning/java/concurrent/OrnamentalGarden.java‎

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package com.brianway.learning.java.concurrent;
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import java.util.ArrayList;
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import java.util.List;
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import java.util.Random;
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import java.util.concurrent.ExecutorService;
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import java.util.concurrent.Executors;
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import java.util.concurrent.TimeUnit;
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class Count {
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private int count = 0;
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private Random rand = new Random(47);
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// Remove the synchronized keyword to see counting fail:
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public synchronized int increment() {
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int temp = count;
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if (rand.nextBoolean()) // Yield half the time
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{
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Thread.yield();
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}
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return (count = ++temp);
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}
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public synchronized int value() {
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return count;
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}
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}
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class Entrance implements Runnable {
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private static Count count = new Count();
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private static List<Entrance> entrances =
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new ArrayList<Entrance>();
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private int number = 0;
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// Doesn't need synchronization to read:
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private final int id;
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private static volatile boolean canceled = false;
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// Atomic operation on a volatile field:
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public static void cancel() {
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canceled = true;
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}
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public Entrance(int id) {
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this.id = id;
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// Keep this task in a list. Also prevents
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// garbage collection of dead tasks:
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entrances.add(this);
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}
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public void run() {
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while (!canceled) {
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synchronized (this) {
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++number;
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}
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System.out.println(this + " Total: " + count.increment());
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try {
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TimeUnit.MILLISECONDS.sleep(100);
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} catch (InterruptedException e) {
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System.out.println("sleep interrupted");
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}
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}
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System.out.println("Stopping " + this);
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}
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public synchronized int getValue() {
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return number;
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}
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public String toString() {
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return "Entrance " + id + ": " + getValue();
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}
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public static int getTotalCount() {
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return count.value();
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}
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public static int sumEntrances() {
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int sum = 0;
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for (Entrance entrance : entrances)
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sum += entrance.getValue();
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return sum;
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}
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}
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public class OrnamentalGarden {
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public static void main(String[] args) throws Exception {
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ExecutorService exec = Executors.newCachedThreadPool();
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for (int i = 0; i < 5; i++)
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exec.execute(new Entrance(i));
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// Run for a while, then stop and collect the data:
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TimeUnit.SECONDS.sleep(3);
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Entrance.cancel();
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exec.shutdown();
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if (!exec.awaitTermination(250, TimeUnit.MILLISECONDS)) {
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System.out.println("Some tasks were not terminated!");
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}
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System.out.println("Total: " + Entrance.getTotalCount());
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System.out.println("Sum of Entrances: " + Entrance.sumEntrances());
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}
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}
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