package org.rui.thread.block; /**
* 被相互排斥堵塞 就像在interrupting.java中看到的，假设你偿试着在一个对象上调用其synchronized方法，
* 而这个对象的锁已经被其它任务获得，那么调用任务将被挂起（堵塞） ，直至这个锁可获得.
* 以下的演示样例说明了同一个相互排斥能够怎样能被同一个任务多次获得
*
* @author lenovo
*
*/
public class MultiLock {
public synchronized void f1(int count) {
if (count-- > 0) {
System.out.println("f1() calling f2() with count " + count);
f2(count);
}
} public synchronized void f2(int count){
if(count-->0){
System.out.println("f2() calling f1() with count "+count);
f1(count);
}
} public static void main(String[] args) {
final MultiLock multiLock=new MultiLock();
new Thread(){
public void run(){
multiLock.f1(10);
}
}.start();
}
}
/**OUTPUT:
f1() calling f2() with count 9
f2() calling f1() with count 8
f1() calling f2() with count 7
f2() calling f1() with count 6
f1() calling f2() with count 5
f2() calling f1() with count 4
f1() calling f2() with count 3
f2() calling f1() with count 2
f1() calling f2() with count 1
f2() calling f1() with count 0
*/
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package org.rui.thread.block; import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock; //Mutex 相互排斥 Reentrant :可重入
class BlockedMutex {
private Lock lock = new ReentrantLock(); public BlockedMutex() {
// Acquire it reght away, to demonstrate interruption 获取它心中,来演示中断
// of a task blocked on a ReentrantLock reentrantLock的任务了
lock.lock();
} public void f() {
try {
// this will nerer be available to a second task 这将纵然是可用的第二个任务
lock.lockInterruptibly();// 假设当前线程未被中断，则获取锁 special call
System.out.println("lock acquired in f()");
} catch (InterruptedException e) {
System.out.println("interrupted from lock acuisition in f()");
}
}
} class Blocked2 implements Runnable {
BlockedMutex blocked = new BlockedMutex(); @Override
public void run() {
System.out.println("Waiting for f() in BlockedMutex");
blocked.f();
System.out.println("Broken out of blocked call");//爆发的堵塞调用 } } public class Interruptiing2 {
public static void main(String[] args) throws InterruptedException {
Thread t=new Thread(new Blocked2());
t.start();
TimeUnit.SECONDS.sleep(1);
System.out.println("Issuing t.interrupt()");
//t.interrupt();//中断线程
}
}
/**
* output:
Waiting for f() in BlockedMutex
Issuing t.interrupt()
interrupted from lock acuisition in f()
Broken out of blocked call
*/
package org.rui.thread.block; import java.util.concurrent.TimeUnit;
/**
* 检查中断
* @author lenovo
*
*/
class NeedsCleanup {//须要清除
private final int id; public NeedsCleanup(int ident) {
id = ident;
System.out.println("NeedsCleanup " + id);
} public void cleanup() {
System.out.println("Cleaning up " + id);
}
} class Blocked3 implements Runnable {
private volatile double d = 0.0; public void run() {
try {
while (!Thread.interrupted()) {
// point1
NeedsCleanup n1 = new NeedsCleanup(1);
// start try-finally immediately after definition
// of n1 , to auarantee proper cleanup of n1
try {
System.out.println("sleeping");
TimeUnit.SECONDS.sleep(1);
// point 2
NeedsCleanup n2 = new NeedsCleanup(2);
// guarantee proper cleanup of n2 保证适当的清理n2
try {
System.out.println("计算单元");
// A time-consuming,non-blocking operation: 耗时,非堵塞操作
for (int i = 1; i < 2500000; i++) {
d = d + (Math.PI + Math.E) / d;
}
System.out.println("完毕耗时的操作");
} finally {
n2.cleanup();
} } finally {
n1.cleanup();
//throw new InterruptedException();
}
}
System.out.println("exiting via while() test");
} catch (InterruptedException e) {
System.out.println("exiting via inerruptedExecption");
}
}
} // ///////////////////////////////////// public class InterruptingIdiom { public static void main(String[] args) throws Exception {
String[] arg = { "1100" };
if (arg.length != 1) {
System.exit(1);
}
Thread t = new Thread(new Blocked3());
t.start();
TimeUnit.MILLISECONDS.sleep(new Integer(arg[0]));
t.interrupt();
}
}
/**
output: NeedsCleanup 1
sleeping
NeedsCleanup 2
计算单元
完毕耗时的操作
Cleaning up 2
Cleaning up 1
NeedsCleanup 1
sleeping
Cleaning up 1
exiting via inerruptedExecption
*/
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