package org.audit4j.core.schedule;
import java.util.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import org.audit4j.core.schedule.util.ClassUtils;
import org.audit4j.core.schedule.util.ErrorHandler;
/**
* Implementation of Spring's {@link TaskScheduler} interface, wrapping a native.
*
* {@link java.util.concurrent.ScheduledThreadPoolExecutor}.
* @author Juergen Hoeller
* @author Mark Fisher
* @since 3.0
* @see #setPoolSize
* @see #setRemoveOnCancelPolicy
* @see #setThreadFactory
* @see #setErrorHandler
*/
@SuppressWarnings("serial")
public class ThreadPoolTaskScheduler implements AsyncTaskExecutor, SchedulingTaskExecutor, TaskScheduler {
// ScheduledThreadPoolExecutor.setRemoveOnCancelPolicy(boolean) only
// available on JDK 7+
/** The Constant setRemoveOnCancelPolicyAvailable. */
private static final boolean setRemoveOnCancelPolicyAvailable = ClassUtils.hasMethod(
ScheduledThreadPoolExecutor.class, "setRemoveOnCancelPolicy", boolean.class);
/** The pool size. */
private volatile int poolSize = 1;
/** The remove on cancel policy. */
private volatile boolean removeOnCancelPolicy = false;
/** The scheduled executor. */
private volatile ScheduledExecutorService scheduledExecutor;
/** The error handler. */
private volatile ErrorHandler errorHandler;
/**
* Set the ScheduledExecutorService's pool size. Default is 1.
* <p>
* <b>This setting can be modified at runtime, for example through JMX.</b>
*
* @param poolSize the new pool size
*/
public void setPoolSize(int poolSize) {
// Assert.isTrue(poolSize > 0, "'poolSize' must be 1 or higher");
this.poolSize = poolSize;
if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setCorePoolSize(poolSize);
}
}
/**
* Set the remove-on-cancel mode on {@link ScheduledThreadPoolExecutor} (JDK
* 7+).
* <p>
* Default is {@code false}. If set to {@code true}, the target executor
* will be switched into remove-on-cancel mode (if possible, with a soft
* fallback otherwise).
* <p>
* <b>This setting can be modified at runtime, for example through JMX.</b>
*
* @param removeOnCancelPolicy the new removes the on cancel policy
*/
// @UsesJava7
public void setRemoveOnCancelPolicy(boolean removeOnCancelPolicy) {
this.removeOnCancelPolicy = removeOnCancelPolicy;
if (setRemoveOnCancelPolicyAvailable && this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(removeOnCancelPolicy);
} else if (removeOnCancelPolicy && this.scheduledExecutor != null) {
// logger.info("Could not apply remove-on-cancel policy - not a Java 7+ ScheduledThreadPoolExecutor");
}
}
/**
* Set a custom {@link ErrorHandler} strategy.
*
* @param errorHandler the new error handler
*/
public void setErrorHandler(ErrorHandler errorHandler) {
this.errorHandler = errorHandler;
}
// @UsesJava7
// @Override
/**
* Initialize executor.
*
* @param threadFactory the thread factory
* @param rejectedExecutionHandler the rejected execution handler
* @return the executor service
*/
protected ExecutorService initializeExecutor(ThreadFactory threadFactory,
RejectedExecutionHandler rejectedExecutionHandler) {
this.scheduledExecutor = createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);
if (this.removeOnCancelPolicy) {
if (setRemoveOnCancelPolicyAvailable && this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(true);
} else {
// logger.info("Could not apply remove-on-cancel policy - not a Java 7+ ScheduledThreadPoolExecutor");
}
}
return this.scheduledExecutor;
}
/**
* Create a new {@link ScheduledExecutorService} instance.
* <p>
* The default implementation creates a {@link ScheduledThreadPoolExecutor}.
* Can be overridden in subclasses to provide custom
*
* @param poolSize the specified pool size
* @param threadFactory the ThreadFactory to use
* @param rejectedExecutionHandler the RejectedExecutionHandler to use
* @return a new ScheduledExecutorService instance
* {@link ScheduledExecutorService} instances.
* @see #afterPropertiesSet()
* @see java.util.concurrent.ScheduledThreadPoolExecutor
*/
protected ScheduledExecutorService createExecutor(int poolSize, ThreadFactory threadFactory,
RejectedExecutionHandler rejectedExecutionHandler) {
return new ScheduledThreadPoolExecutor(poolSize, threadFactory, rejectedExecutionHandler);
}
/**
* Return the underlying ScheduledExecutorService for native access.
*
* @return the underlying ScheduledExecutorService (never {@code null})
* @throws IllegalStateException
* if the ThreadPoolTaskScheduler hasn't been initialized yet
*/
public ScheduledExecutorService getScheduledExecutor() throws IllegalStateException {
// Assert.state(this.scheduledExecutor != null,
// "ThreadPoolTaskScheduler not initialized");
return this.scheduledExecutor;
}
/**
* Return the underlying ScheduledThreadPoolExecutor, if available.
*
* @return the underlying ScheduledExecutorService (never {@code null})
* @throws IllegalStateException
* if the ThreadPoolTaskScheduler hasn't been initialized yet or
* if the underlying ScheduledExecutorService isn't a
* ScheduledThreadPoolExecutor
* @see #getScheduledExecutor()
*/
public ScheduledThreadPoolExecutor getScheduledThreadPoolExecutor() throws IllegalStateException {
// Assert.state(this.scheduledExecutor instanceof
// ScheduledThreadPoolExecutor,
// "No ScheduledThreadPoolExecutor available");
return (ScheduledThreadPoolExecutor) this.scheduledExecutor;
}
/**
* Return the current pool size.
* <p>
* Requires an underlying {@link ScheduledThreadPoolExecutor}.
*
* @return the pool size
* @see #getScheduledThreadPoolExecutor()
* @see java.util.concurrent.ScheduledThreadPoolExecutor#getPoolSize()
*/
public int getPoolSize() {
if (this.scheduledExecutor == null) {
// Not initialized yet: assume initial pool size.
return this.poolSize;
}
return getScheduledThreadPoolExecutor().getPoolSize();
}
/**
* Return the current setting for the remove-on-cancel mode.
* <p>
* Requires an underlying {@link ScheduledThreadPoolExecutor}.
*
* @return true, if is removes the on cancel policy
*/
// @UsesJava7
public boolean isRemoveOnCancelPolicy() {
if (!setRemoveOnCancelPolicyAvailable) {
return false;
}
if (this.scheduledExecutor == null) {
// Not initialized yet: return our setting for the time being.
return this.removeOnCancelPolicy;
}
return getScheduledThreadPoolExecutor().getRemoveOnCancelPolicy();
}
/**
* Return the number of currently active threads.
* <p>
* Requires an underlying {@link ScheduledThreadPoolExecutor}.
*
* @return the active count
* @see #getScheduledThreadPoolExecutor()
* @see java.util.concurrent.ScheduledThreadPoolExecutor#getActiveCount()
*/
public int getActiveCount() {
if (this.scheduledExecutor == null) {
// Not initialized yet: assume no active threads.
return 0;
}
return getScheduledThreadPoolExecutor().getActiveCount();
}
// SchedulingTaskExecutor implementation
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskExecutor#execute(java.lang.Runnable)
*
*/
@Override
public void execute(Runnable task) {
Executor executor = getScheduledExecutor();
try {
executor.execute(errorHandlingTask(task, false));
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.AsyncTaskExecutor#execute(java.lang.Runnable, long)
*
*/
@Override
public void execute(Runnable task, long startTimeout) {
execute(task);
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.AsyncTaskExecutor#submit(java.lang.Runnable)
*
*/
@Override
public Future<?> submit(Runnable task) {
ExecutorService executor = getScheduledExecutor();
try {
return executor.submit(errorHandlingTask(task, false));
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.AsyncTaskExecutor#submit(java.util.concurrent.Callable)
*
*/
@Override
public <T> Future<T> submit(Callable<T> task) {
ExecutorService executor = getScheduledExecutor();
try {
Callable<T> taskToUse = task;
if (this.errorHandler != null) {
taskToUse = new DelegatingErrorHandlingCallable<T>(task, this.errorHandler);
}
return executor.submit(taskToUse);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.SchedulingTaskExecutor#prefersShortLivedTasks()
*
*/
@Override
public boolean prefersShortLivedTasks() {
return true;
}
// TaskScheduler implementation
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#schedule(java.lang.Runnable, org.audit4j.core.schedule.Trigger)
*
*/
@Override
public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
ErrorHandler errorHandlerLocal = this.errorHandler != null ? this.errorHandler : TaskUtils
.getDefaultErrorHandler(true);
return new ReschedulingRunnable(task, trigger, executor, errorHandlerLocal).schedule();
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#schedule(java.lang.Runnable, java.util.Date)
*
*/
@Override
public ScheduledFuture<?> schedule(Runnable task, Date startTime) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.schedule(errorHandlingTask(task, false), initialDelay, TimeUnit.MILLISECONDS);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#scheduleAtFixedRate(java.lang.Runnable, java.util.Date, long)
*
*/
@Override
public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Date startTime, long period) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.scheduleAtFixedRate(errorHandlingTask(task, true), initialDelay, period,
TimeUnit.MILLISECONDS);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#scheduleAtFixedRate(java.lang.Runnable, long)
*
*/
@Override
public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, long period) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
return executor.scheduleAtFixedRate(errorHandlingTask(task, true), 0, period, TimeUnit.MILLISECONDS);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#scheduleWithFixedDelay(java.lang.Runnable, java.util.Date, long)
*
*/
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Date startTime, long delay) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), initialDelay, delay,
TimeUnit.MILLISECONDS);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* {@inheritDoc}
*
* @see org.audit4j.core.schedule.TaskScheduler#scheduleWithFixedDelay(java.lang.Runnable, long)
*
*/
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, long delay) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), 0, delay, TimeUnit.MILLISECONDS);
} catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* Error handling task.
*
* @param task the task
* @param isRepeatingTask the is repeating task
* @return the runnable
*/
private Runnable errorHandlingTask(Runnable task, boolean isRepeatingTask) {
return TaskUtils.decorateTaskWithErrorHandler(task, this.errorHandler, isRepeatingTask);
}
/**
* The Class DelegatingErrorHandlingCallable.
*
* @param <V> the value type
* @author <a href="mailto:[email protected]">Janith Bandara</a>
* @since
*/
private static class DelegatingErrorHandlingCallable<V> implements Callable<V> {
/** The delegate. */
private final Callable<V> delegate;
/** The error handler. */
private final ErrorHandler errorHandler;
/**
* Instantiates a new delegating error handling callable.
*
* @param delegate the delegate
* @param errorHandler the error handler
*/
public DelegatingErrorHandlingCallable(Callable<V> delegate, ErrorHandler errorHandler) {
this.delegate = delegate;
this.errorHandler = errorHandler;
}
/**
* {@inheritDoc}
*
* @see java.util.concurrent.Callable#call()
*
*/
@Override
public V call() throws Exception {
try {
return this.delegate.call();
} catch (Throwable t) {
this.errorHandler.handleError(t);
return null;
}
}
}
}
