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/*-
* ============LICENSE_START=======================================================
* ONAP
* ================================================================================
* Copyright (C) 2017-2020 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ============LICENSE_END=========================================================
*/
package org.onap.policy.controlloop.eventmanager;
import java.time.Instant;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;
import org.onap.policy.controlloop.ControlLoopOperation;
import org.onap.policy.controlloop.actorserviceprovider.OperationOutcome;
import org.onap.policy.controlloop.actorserviceprovider.OperationResult;
import org.onap.policy.drools.core.lock.Lock;
import org.onap.policy.drools.core.lock.LockCallback;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Data for an individual lock.
*/
public class LockData implements LockCallback {
private static final Logger logger = LoggerFactory.getLogger(LockData.class);
private final String targetEntity;
private final UUID requestId;
/**
* Time when this was created.
*/
private final Instant createTime = Instant.now();
/**
* Future for obtaining the lock. Initially incomplete.
*/
private final AtomicReference<CompletableFuture<OperationOutcome>> future =
new AtomicReference<>(new CompletableFuture<>());
/**
* The lock.
*/
private Lock theLock = null;
/**
* Listeners to invoke if the lock is unavailable/lost.
*/
private final List<Consumer<OperationOutcome>> unavailableCallbacks = new ArrayList<>();
/**
* Set to a failed outcome, if the lock becomes unavailable.
*/
private OperationOutcome failedOutcome = null;
/**
* Constructs the object.
*
* @param targetEntity target entity
*/
public LockData(String targetEntity, UUID requestId) {
this.targetEntity = targetEntity;
this.requestId = requestId;
}
/**
* Gets the future to be completed when the lock operation completes.
*
* @return the lock operation future
*/
public CompletableFuture<OperationOutcome> getFuture() {
return future.get();
}
/**
* Adds a callback to be invoked if the lock becomes unavailable.
*
* @param callback callback to be added
*/
public void addUnavailableCallback(Consumer<OperationOutcome> callback) {
synchronized (this) {
if (failedOutcome == null) {
// hasn't failed yet - add it to the list
unavailableCallbacks.add(callback);
return;
}
}
// already failed - invoke the callback immediately
callback.accept(failedOutcome);
}
/**
* Frees the lock.
*/
public void free() {
Lock lock;
synchronized (this) {
if ((lock = theLock) == null) {
return;
}
}
lock.free();
}
@Override
public synchronized void lockAvailable(Lock lock) {
logger.warn("lock granted on {} for {}", targetEntity, requestId);
theLock = lock;
OperationOutcome outcome = makeOutcome();
outcome.setResult(OperationResult.SUCCESS);
outcome.setMessage(ControlLoopOperation.SUCCESS_MSG);
future.get().complete(outcome);
}
@Override
public void lockUnavailable(Lock unused) {
synchronized (this) {
logger.warn("lock unavailable on {} for {}", targetEntity, requestId);
failedOutcome = makeOutcome();
failedOutcome.setResult(OperationResult.FAILURE);
failedOutcome.setMessage(ControlLoopOperation.FAILED_MSG);
}
/*
* In case the future was already completed successfully, replace it with a failed
* future, but complete the old one, too, in case it wasn't completed yet.
*/
future.getAndSet(CompletableFuture.completedFuture(failedOutcome)).complete(failedOutcome);
for (Consumer<OperationOutcome> callback : unavailableCallbacks) {
try {
callback.accept(new OperationOutcome(failedOutcome));
} catch (RuntimeException e) {
logger.warn("lock callback threw an exception for {}", requestId, e);
}
}
unavailableCallbacks.clear();
}
/**
* Makes a lock operation outcome.
*
* @return a new lock operation outcome
*/
private OperationOutcome makeOutcome() {
OperationOutcome outcome = new OperationOutcome();
outcome.setActor(ControlLoopOperationManager2.LOCK_ACTOR);
outcome.setOperation(ControlLoopOperationManager2.LOCK_OPERATION);
outcome.setTarget(targetEntity);
outcome.setFinalOutcome(true);
outcome.setStart(createTime);
outcome.setEnd(Instant.now());
return outcome;
}
}
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