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/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package com.sun.ejb.containers;
import com.sun.ejb.EjbInvocation;
import java.util.concurrent.FutureTask;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.TimeUnit;
/**
* @author Mahesh Kannan
*/
public class EjbFutureTask
extends FutureTask {
private EjbAsyncTask ejbAsyncTask;
// Used to remember if cancel() was called already
private boolean cancelCalled = false;
// State which could be set from both the caller's thread and
// the thread on which the task is executing.
private volatile boolean complete = false;
private volatile V resultValue;
private volatile Throwable resultException;
public EjbFutureTask(EjbAsyncTask callable, EjbAsyncInvocationManager mgr) {
super(callable);
this.ejbAsyncTask = callable;
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
if( !cancelCalled ) {
cancelCalled = true;
// mayInterruptIfRunning only determines whether the bean method
// has visibility to the fact that the caller called Future.cancel().
if( mayInterruptIfRunning ) {
EjbInvocation inv = ejbAsyncTask.getEjbInvocation();
inv.setWasCancelCalled(true);
}
}
// For now we don't even try checking to see if the task has started running.
// Just return false so the caller knows the task could not be cancelled.
return false;
}
@Override
public V get() throws InterruptedException, ExecutionException {
// If get() has already been called, produce the same behavior
// as initial call, except if get(timeout, unit) resulted in a
// TimeoutException
if( !complete ) {
try {
super.get();
// result value is set directly by AsyncTask
} catch(ExecutionException ee) {
// already set directly by AsyncTask
} catch(InterruptedException ie) {
setResultException(ie);
} catch(RuntimeException re) {
setResultException(re);
}
}
// We really shouldn't get CancellationException or
// InterruptedException, but throw whatever kind we get.
if( resultException != null ) {
if( resultException instanceof ExecutionException ) {
throw (ExecutionException) resultException;
} else if( resultException instanceof InterruptedException) {
throw (InterruptedException) resultException;
} else {
throw (RuntimeException) resultException;
}
}
return resultValue;
}
@Override
public V get(long timeout, TimeUnit unit)
throws InterruptedException, ExecutionException, TimeoutException {
// If get() has already been called, produce the same behavior
// as initial call, except if get(timeout, unit) resulted in a
// TimeoutException
if( !complete ) {
try {
super.get(timeout, unit);
} catch(ExecutionException ee) {
// already set directly by AsyncTask
} catch(TimeoutException t) {
// If it's a TimeoutException, complete will not have been set.
// In that case just rethrow the TimeoutException without
// remembering it in resultException. That way, the caller
// can call get() or get(timeout, unit) to try again.
throw t;
} catch(InterruptedException ie) {
setResultException(ie);
} catch(RuntimeException re) {
setResultException(re);
}
}
// We really shouldn't get CancellationException or
// InterruptedException, but throw whatever kind we get.
if( resultException != null ) {
if( resultException instanceof ExecutionException ) {
throw (ExecutionException) resultException;
} else if( resultException instanceof InterruptedException) {
throw (InterruptedException) resultException;
} else {
throw (RuntimeException) resultException;
}
}
return resultValue;
}
@Override
public boolean isCancelled() {
// For now, we don't ever actually forcibly cancel a task
// that hasn't executed.
return false;
}
@Override
public boolean isDone() {
// Per the Future javadoc. It's a little odd that isDone()
// is required to return true even if cancel() was called but
// returned false. However, that's the behavior. There's nothing
// stopping the caller from still calling get() though.
return (cancelCalled || complete);
}
EjbAsyncTask getEjbAsyncTask() {
return ejbAsyncTask;
}
long getInvId() {
return ejbAsyncTask.getInvId();
}
void setResultValue(V v) {
// EjbAsyncTask calls this directly. That way
// we can return true from isDone() after completion of
// the task, even if get() was not called.
resultValue = v;
complete = true;
}
void setResultException(Throwable t) {
// EjbAsyncTask calls this directly. That way
// we can return true from isDone() after completion of
// the task, even if get() was not called.
resultException = t;
complete = true;
}
// Internal method to retrieve any result value
V getResultValue() {
return resultValue;
}
Throwable getResultException() {
return resultException;
}
public String toString() {
StringBuffer sbuf = new StringBuffer();
sbuf.append("EjbFutureTask ");
sbuf.append("taskId="+ejbAsyncTask.getInvId());
sbuf.append(",cancelCalled="+cancelCalled);
sbuf.append(",complete="+complete);
if( complete ) {
if( resultException == null ) {
sbuf.append(",resultValue="+resultValue);
} else {
sbuf.append(",resultException="+resultException);
}
}
return sbuf.toString();
}
}