CancellableCallable.java
/*
** Module : CancellableCallable.java
** Abstract : Cancellable callable.
**
** Copyright (c) 2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 GBB 20250122 Created initial version.
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
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**
** This license does not grant any license or rights to use the trademarks
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** attribution required in this license.
*/
package com.goldencode.p2j.util.appserver;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.function.*;
/** Cancellable callable. */
abstract class CancellableCallable<V>
implements Callable<V>
{
/** The MSA task that is running as part of the callable. */
private MultiSessionAppserver.MsaTask task;
/** Thread-safe flag indicating if the MSA task is running. */
private final AtomicBoolean isRunning = new AtomicBoolean(false);
/** Thread-safe flag indicating if the MSA task is cancelled. */
private final AtomicBoolean isCancelled = new AtomicBoolean(false);
/** The Future for a nested task that is currently running and can be cancelled. */
private Future currentlyRunningFuture;
/** The cause for the cancel of the callable. */
private CancelCause cancelCause;
/**
* Sends STOP by cancelling the task and interrupting the running thread.
*
* @param cancelCause
* The cause for the cancel.
*/
void sendStop(CancelCause cancelCause)
{
Thread executorThread = getExecutorThread();
if (executorThread != null)
{
this.cancelCause = cancelCause;
isCancelled.set(true);
executorThread.interrupt();
}
}
/**
* Cancels the Future for the currently running task, excluding the MSA task itself. Used for
* requestWaitTimeout.
*
* @param cancelCause
* The cause for the cancel.
*/
void cancel(CancelCause cancelCause)
{
this.cancelCause = cancelCause;
isCancelled.set(true);
if (currentlyRunningFuture != null)
{
currentlyRunningFuture.cancel(true);
}
}
/**
* Sets the Future for the currently running nested task.
*
* @param future
* The Future for the currently running nested task.
*/
void setCurrentlyRunningFuture(Future future)
{
this.currentlyRunningFuture = future;
}
/**
* Returns <code>true</code> if the MSA task is cancelled, <code>false</code> otherwise.
*
* @return See above.
*/
boolean isCancelled()
{
return isCancelled.get();
}
/**
* Returns the cause of the cancel, <code>null</code> when the callable is not cancelled.
*
* @return See above.
*/
CancelCause getCancelCause()
{
return cancelCause;
}
/**
* Returns <code>true</code> if the MSA task is running, <code>false</code> otherwise.
*
* @return See above.
*/
boolean isRunning()
{
return isRunning.get();
}
/**
* Returns a thread-safe flag indicating if the MSA task is cancelled.
*
* @return See above.
*/
AtomicBoolean getCancelledSupplier()
{
return isCancelled;
}
/**
* Returns a thread-safe flag indicating if the MSA task is running.
*
* @return See above.
*/
AtomicBoolean getIsRunningSupplier()
{
return isRunning;
}
/**
* Returns a new Function that can be used to set the MSA task.
*
* @return See above.
*/
Function<MultiSessionAppserver.MsaTask, Void> getTaskReceiver()
{
return msaTask ->
{
this.task = msaTask;
return null;
};
}
/**
* Returns the Thread on which the executor is running the MSA task, <code>null</code> if the MSA
* task hasn't started running.
*
* @return See above.
*/
private Thread getExecutorThread()
{
return task == null ? null : task.getRunningThread();
}
}