装饰Java';s可以调用以添加行为
让我们假设我们有可能长期运行的任务:装饰Java';s可以调用以添加行为,java,multithreading,concurrency,threadpool,callable,Java,Multithreading,Concurrency,Threadpool,Callable,让我们假设我们有可能长期运行的任务: public class LongRunningTask { public ReturnType doSomething() { ... } } 我们希望同时运行这些任务中的许多 所以,我有我的电话: public class LongRunningCallable implements Callable<LongRunningTask> { private final LongRunningTask t
public class LongRunningTask {
public ReturnType doSomething() {
...
}
}
我们希望同时运行这些任务中的许多
所以,我有我的电话:
public class LongRunningCallable implements Callable<LongRunningTask> {
private final LongRunningTask task;
...
public ReturnType call() {
return task.doSomething();
}
...
}
公共类LongRunningCallable实现可调用{
私有最终LongRunningTask任务;
...
公共ReturnType调用(){
返回task.doSomething();
}
...
}
现在,因为这可能会持续很长时间,我不想限制它只运行一定数量。所以,我可能会这样做:
public class InterruptibleCallable<T> implements Callable<T> {
protected final long timeout;
protected final TimeUnit timeUnit;
protected final Callable<T> callable;
public InterruptibleCallable(long timeout, TimeUnit timeUnit, Callable<T> callable) {
this.timeout = timeout;
this.timeUnit = timeUnit;
this.callable = callable;
}
@Override
public T call() throws Exception {
ExecutorService executorService = Executors.newSingleThreadExecutor();
T result = null;
try {
result = executorService.submit(callable).get(timeout, timeUnit);
} catch (InterruptedException e) {
LOGGER.error("Callable: " + callable.toString() + " was interrupted");
throw e;
} catch (ExecutionException e) {
throw e;
} catch (TimeoutException e) {
LOGGER.warn("Callable: " + callable.toString() + " timed out after " + timeout + " " + timeUnit);
throw e;
} finally {
executorService.shutdown();
}
return result;
}
}
public类interruptablecallable实现可调用{
受保护的最终长超时;
受保护的最终时间单位;
受保护的最终可调用;
public interruptablecallable(长超时、TimeUnit TimeUnit、Callable Callable){
this.timeout=超时;
this.timeUnit=时间单位;
this.callable=可调用;
}
@凌驾
public T call()引发异常{
ExecutorService ExecutorService=Executors.newSingleThreadExecutor();
T结果=null;
试一试{
结果=executorService.submit(可调用).get(超时,时间单位);
}捕捉(中断异常e){
LOGGER.error(“Callable:+Callable.toString()+”被中断”);
投掷e;
}捕获(执行例外){
投掷e;
}捕获(超时异常e){
LOGGER.warn(“可调用:“+Callable.toString()+”在“+timeout+”+timeUnit”之后超时);
投掷e;
}最后{
executorService.shutdown();
}
返回结果;
}
}
这没关系,但现在我还想包装它,以便它在遇到异常时可以重试(延迟):
public class RetryableCallable<T> implements Callable<T> {
private final long delay;
private final TimeUnit timeUnit;
private final Callable<T> callable;
@Override
public T call() throws Exception {
T result = null;
try {
ExecutorService executorService = Executors.newSingleThreadExecutor();
result = executorService.submit(this.callable).get();
} catch (Exception e) {
ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
result = executorService.schedule(this.callable, delay, timeUnit).get();
}
return result;
}
}
public类RetryableCallable实现可调用{
私人最终长时间延迟;
私人最终计时单位;
私人最终可赎回;
@凌驾
public T call()引发异常{
T结果=null;
试一试{
ExecutorService ExecutorService=Executors.newSingleThreadExecutor();
结果=executorService.submit(this.callable.get();
}捕获(例外e){
ScheduledExecutorService executorService=Executors.newSingleThreadScheduledExecutor();
结果=executorService.schedule(this.callable,delay,timeUnit).get();
}
返回结果;
}
}
现在,我的问题是:
谢谢:D围绕
interruptablecallable
包装LongRunningTask
并在每个RetryableCallable
上创建两个额外的执行器执行错误
当RetryableCallable
捕获TimeoutException
时,通常不应再次运行相同的任务。这有点让人困惑,因为若任务被超时“杀死”,为什么还要再运行一次呢?
还有,为什么您需要在这里创建另一个执行人?保持简单
public class RetryableCallable<T> implements Callable<T> {
private int retries = 3;
@Override
public T call() throws Exception {
while (retries-- > 0) {
try {
return callable.call();
} catch (InterruptedException e) {
LOGGER.error("Callable: " + callable.toString() + " was interrupted");
throw e;
} catch (TimeoutException e) {
LOGGER.warn("Callable: " + callable.toString() + " timed out after " + timeout + " " + timeUnit);
throw e;
} catch (Exception e) {
LOGGER.warn("Callable: " + callable.toString() + " failed");
}
}
throw new IllegalStateException();//or return null
}
}
public类RetryableCallable实现可调用{
私人整数重试次数=3次;
@凌驾
public T call()引发异常{
同时(重试-->0){
试一试{
返回callable.call();
}捕捉(中断异常e){
LOGGER.error(“Callable:+Callable.toString()+”被中断”);
投掷e;
}捕获(超时异常e){
LOGGER.warn(“可调用:“+Callable.toString()+”在“+timeout+”+timeUnit”之后超时);
投掷e;
}捕获(例外e){
LOGGER.warn(“Callable:+Callable.toString()+”失败);
}
}
抛出新的IllegalStateException();//或返回null
}
}
它不应该使用超时和延迟,它是RetryableCallable
但不是RetryableCallableWithDelayAndTimeoutAndSomethingElse
如果您想限制任务的执行时间,我认为至少有4种好方法:
- 在提交它的线程中调用
get(time,timeunit)
- 将任务的执行时间限制在
函数中,例如,通过“定期”检查我们是否有更多的时间call()
- 创建您自己的executor类,其中包含自定义executor和一个线程审计员,该类将接受一些
,它扩展了TimeLimitedCallable
,并具有Callable
函数。审核员将控制所有执行int getTimeLimit()
的运行任务的时间范围TimeLimitedCallable
- 为“任务的审核员”创建一个单独的执行者,并在将一个(或一组)具有业务逻辑的任务提交到主执行者之后,创建审核员任务并将其提交到单独的执行者