/*
* Copyright 2014 JBoss Inc
*
* 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.
*/
package org.drools.persistence.jta;
import java.util.concurrent.locks.ReentrantLock;
import org.drools.core.command.impl.AbstractInterceptor;
import org.drools.persistence.OrderedTransactionSynchronization;
import org.drools.persistence.TransactionManager;
import org.drools.persistence.TransactionManagerHelper;
import org.kie.api.command.Command;
import org.kie.api.runtime.Environment;
import org.kie.api.runtime.EnvironmentName;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Interceptor that will lock underlying <code>CommandService</code> until transaction completion.
* In case there is no transaction active lock is released directly.
*
* By default, interceptor is disabled and needs to be explicitly enabled in one of two ways:
* <ul>
* <li>using system property named <code>org.kie.tx.lock.enabled</code> that must be set to true</li>
* <li>using environment entry named <code>TRANSACTION_LOCK_ENABLED</code> that must be set to true</li>
* </ul>
*/
public class TransactionLockInterceptor extends AbstractInterceptor {
private static final Logger logger = LoggerFactory.getLogger(TransactionLockInterceptor.class);
private boolean active = false;
private ReentrantLock lock = new ReentrantLock();
private Environment environment;
public TransactionLockInterceptor(Environment environment) {
this.environment = environment;
this.active = Boolean.getBoolean("org.kie.tx.lock.enabled");
if (environment.get("TRANSACTION_LOCK_ENABLED") != null) {
this.active = Boolean.parseBoolean(environment.get("TRANSACTION_LOCK_ENABLED").toString());
}
logger.debug("Transaction lock interceptor enabled " + this.active);
}
@Override
public <T> T execute(Command<T> command) {
if (!active) {
return executeNext(command);
}
// proceed only when explicitly activated
boolean locked = false;
if (!lock.isHeldByCurrentThread()) {
logger.debug("About to get a lock on command service by {}", Thread.currentThread().getName());
lock.lock();
locked = true;
logger.debug("Lock taken by {}", Thread.currentThread().getName());
}
try {
return executeNext(command);
} finally {
if (locked) {
logger.debug("About to register lock release handler by {}", Thread.currentThread().getName());
release((TransactionManager) environment.get(EnvironmentName.TRANSACTION_MANAGER));
}
}
}
protected void release(TransactionManager txm) {
try {
TransactionManagerHelper.registerTransactionSyncInContainer(txm, new OrderedTransactionSynchronization(100) {
@Override
public void beforeCompletion() {
}
@Override
public void afterCompletion(int status) {
logger.debug("Releasing on transaction completion by {}", Thread.currentThread().getName());
lock.unlock();
logger.debug("Successfully released lock by {}", Thread.currentThread().getName());
}
});
} catch (Throwable e) {
logger.debug("Error happened releasing directly by {} due to {}", Thread.currentThread().getName(), e.getMessage());
lock.unlock();
}
}
}