如何實現自定義同步組件
阿新 • • 發佈：2017-05-27
nds 允許 oid try unlock all 同步 while name
package com.chen;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.AbstractQueuedSynchronizer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
/**
* desc：自定義同步組件，只允許最多n個線程同時訪問
* // 1.共享訪問
* // 2.定義n個資源數
* Created by chenjianye on 2017/5/26.
*/
public class ServerLock implements Lock{
private Sync sync = null;
public ServerLock(int ServerLockNum) {
this.sync = new Sync(ServerLockNum);
}
private final class Sync extends AbstractQueuedSynchronizer {
Sync(int count){
setState(count);
}
public int tryAcquireShared(int reduceCount) {
for(;;) {
int current = getState();
int newCount = current - reduceCount;
if (newCount < 0 || compareAndSetState(current, newCount)) {
return newCount;
}
}
}
public boolean tryReleaseShared(int returnCount) {
for(;;) {
int current = getState();
int newCount = current + returnCount;
if (compareAndSetState(current, newCount)) {
return true;
}
}
}
}
@Override
public void lock() {
// sync.acquire(1);
sync.acquireShared(1);
}
@Override
public void unlock() {
sync.releaseShared(1);
}
@Override
public void lockInterruptibly() throws InterruptedException {
System.out.println("dd");
}
@Override
public boolean tryLock() {
return false;
}
@Override
public boolean tryLock(long time, TimeUnit unit) throws InterruptedException {
return sync.tryAcquireNanos(1, unit.toNanos(1000));
}
@Override
public Condition newCondition() {
throw new RuntimeException("");
}
}
package com.chen;
import java.util.concurrent.locks.Lock;
/**
* desc：測試自定義鎖
* Created by chenjianye on 2017/5/26.
*/
public class TestLock {
public static void main(String[] args) {
ServerLock lock = new ServerLock(4);
// ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
// Lock tmp = lock.writeLock();
for(int i=0;i<20;i++) {
Worker worker = new Worker(lock);
worker.start();
}
}
static class Worker extends Thread{
Lock lock;
Worker(Lock lock) {
this.lock = lock;
}
public void run() {
while (true) {
lock.lock();
try{
Thread.sleep(1000);
System.out.println("Thread name:" + Thread.currentThread().getName()+"時間："+System.currentTimeMillis()/1000);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
lock.unlock();
}
}
}
}
}
如何實現自定義同步組件