public abstract class SocketUsingTask <T> implements CancellableTask<T> {
@GuardedBy("this") private Socket socket;
protected synchronized void setSocket(Socket s) {
socket = s;
}
public synchronized void cancel() {
try {
if (socket != null)
socket.close();
} catch (IOException ignored) {
}
}
//这个方法是重点
public RunnableFuture<T> newTask() {
return new FutureTask<T>(this) {
public boolean cancel(boolean mayInterruptIfRunning) {
try {
SocketUsingTask.this.cancel();
} finally {
return super.cancel(mayInterruptIfRunning);
}
}
};
}
}
//扩展了Callable接口，运用了RunnableFuture
interface CancellableTask <T> extends Callable<T> {
void cancel();
RunnableFuture<T> newTask();
}
@ThreadSafe
class CancellingExecutor extends ThreadPoolExecutor {
public CancellingExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
}
public CancellingExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory);
}
public CancellingExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, RejectedExecutionHandler handler) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler);
}
public CancellingExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue, ThreadFactory threadFactory, RejectedExecutionHandler handler) {
super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
}
protected <T> RunnableFuture<T> newTaskFor(Callable<T> callable) {
if (callable instanceof CancellableTask)
return ((CancellableTask<T>) callable).newTask();
else
return super.newTaskFor(callable);
}
}
RunnableFuture提供了另一种在runnable中取消套接字和线程的方法
