/*
|
* CDDL HEADER START
|
*
|
* The contents of this file are subject to the terms of the
|
* Common Development and Distribution License, Version 1.0 only
|
* (the "License"). You may not use this file except in compliance
|
* with the License.
|
*
|
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
|
* or http://forgerock.org/license/CDDLv1.0.html.
|
* See the License for the specific language governing permissions
|
* and limitations under the License.
|
*
|
* When distributing Covered Code, include this CDDL HEADER in each
|
* file and include the License file at legal-notices/CDDLv1_0.txt.
|
* If applicable, add the following below this CDDL HEADER, with the
|
* fields enclosed by brackets "[]" replaced with your own identifying
|
* information:
|
* Portions Copyright [yyyy] [name of copyright owner]
|
*
|
* CDDL HEADER END
|
*
|
*
|
* Copyright 2009-2010 Sun Microsystems, Inc.
|
*/
|
|
package com.forgerock.opendj.util;
|
|
import java.util.concurrent.Future;
|
import java.util.concurrent.TimeUnit;
|
import java.util.concurrent.TimeoutException;
|
|
import org.forgerock.opendj.ldap.ErrorResultException;
|
import org.forgerock.opendj.ldap.FutureResult;
|
import org.forgerock.opendj.ldap.ResultHandler;
|
|
/**
|
* An implementation of the {@code FutureResult} interface which can be used to
|
* combine a sequence of two asynchronous operations into a single future
|
* result. Implementations should override the methods {@link #chainResult} and
|
* {@link #chainErrorResult} in order to define the second asynchronous
|
* operation.
|
*
|
* @param <M>
|
* The type of the inner result.
|
* @param <N>
|
* The type of the outer result.
|
*/
|
public abstract class RecursiveFutureResult<M, N> implements FutureResult<N>, ResultHandler<M> {
|
|
private final class FutureResultImpl extends AsynchronousFutureResult<N, ResultHandler<? super N>> {
|
|
private FutureResultImpl(final ResultHandler<? super N> handler) {
|
super(handler);
|
}
|
|
@Override
|
public int getRequestID() {
|
if (innerFuture instanceof FutureResult<?>) {
|
final FutureResult<?> tmp = (FutureResult<?>) innerFuture;
|
return tmp.getRequestID();
|
} else {
|
return -1;
|
}
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
protected ErrorResultException handleCancelRequest(final boolean mayInterruptIfRunning) {
|
innerFuture.cancel(mayInterruptIfRunning);
|
if (outerFuture != null) {
|
outerFuture.cancel(mayInterruptIfRunning);
|
}
|
return null;
|
}
|
|
}
|
|
private final FutureResultImpl impl;
|
|
private volatile Future<?> innerFuture = null;
|
|
// This does not need to be volatile since the inner future acts as a
|
// memory barrier.
|
private FutureResult<? extends N> outerFuture = null;
|
|
/**
|
* Creates a new asynchronous result chain which will chain an outer
|
* asynchronous request once the inner asynchronous request completes.
|
*
|
* @param handler
|
* The outer result handler.
|
*/
|
protected RecursiveFutureResult(final ResultHandler<? super N> handler) {
|
this.impl = new FutureResultImpl(handler);
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final boolean cancel(final boolean mayInterruptIfRunning) {
|
return impl.cancel(mayInterruptIfRunning);
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final N get() throws ErrorResultException, InterruptedException {
|
return impl.get();
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final N get(final long timeout, final TimeUnit unit) throws ErrorResultException,
|
TimeoutException, InterruptedException {
|
return impl.get(timeout, unit);
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final int getRequestID() {
|
return impl.getRequestID();
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final void handleErrorResult(final ErrorResultException error) {
|
try {
|
outerFuture = chainErrorResult(error, impl);
|
} catch (final ErrorResultException e) {
|
impl.handleErrorResult(e);
|
}
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final void handleResult(final M result) {
|
try {
|
outerFuture = chainResult(result, impl);
|
} catch (final ErrorResultException e) {
|
impl.handleErrorResult(e);
|
}
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final boolean isCancelled() {
|
return impl.isCancelled();
|
}
|
|
/**
|
* {@inheritDoc}
|
*/
|
@Override
|
public final boolean isDone() {
|
return impl.isDone();
|
}
|
|
/**
|
* Sets the inner future for this result chain. This must be done before
|
* this future is published.
|
*
|
* @param future
|
* The inner future.
|
*/
|
public final void setFutureResult(final Future<?> future) {
|
this.innerFuture = future;
|
}
|
|
/**
|
* Invokes the outer request based on the error result of the inner request
|
* and returns a future representing the result of the outer request.
|
* <p>
|
* The default implementation is to terminate further processing by
|
* re-throwing the inner error result.
|
*
|
* @param innerError
|
* The error result of the inner request.
|
* @param handler
|
* The result handler to be used for the outer request.
|
* @return A future representing the result of the outer request.
|
* @throws ErrorResultException
|
* If the outer request could not be invoked and processing
|
* should terminate.
|
*/
|
protected FutureResult<? extends N> chainErrorResult(final ErrorResultException innerError,
|
final ResultHandler<? super N> handler) throws ErrorResultException {
|
throw innerError;
|
}
|
|
/**
|
* Invokes the outer request based on the result of the inner request and
|
* returns a future representing the result of the outer request.
|
*
|
* @param innerResult
|
* The result of the inner request.
|
* @param handler
|
* The result handler to be used for the outer request.
|
* @return A future representing the result of the outer request.
|
* @throws ErrorResultException
|
* If the outer request could not be invoked and processing
|
* should terminate.
|
*/
|
protected abstract FutureResult<? extends N> chainResult(M innerResult,
|
ResultHandler<? super N> handler) throws ErrorResultException;
|
|
}
|
