| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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.apache.usergrid.batch.job; |
| |
| |
| import java.util.concurrent.TimeUnit; |
| |
| import com.google.inject.Injector; |
| import org.springframework.beans.factory.annotation.Autowired; |
| import org.springframework.stereotype.Component; |
| import org.apache.usergrid.batch.Job; |
| import org.apache.usergrid.batch.JobExecution; |
| import org.apache.usergrid.locking.Lock; |
| import org.apache.usergrid.locking.LockManager; |
| import org.apache.usergrid.persistence.EntityManagerFactory; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import javax.annotation.PostConstruct; |
| |
| |
| /** |
| * Simple abstract job class that performs additional locking to ensure that the job is only executing once. This can be |
| * used if your job could potentially be too slow to invoke JobExceution.heartbeat() before the timeout passes. |
| * |
| * @author tnine |
| */ |
| @Component("OnlyOnceJob") |
| public abstract class OnlyOnceJob implements Job { |
| |
| private static final Logger logger = LoggerFactory.getLogger(OnlyOnceJob.class); |
| |
| private LockManager lockManager; |
| |
| @Autowired |
| private EntityManagerFactory emf; |
| |
| @Autowired |
| private Injector injector; |
| |
| |
| /** |
| * |
| */ |
| public OnlyOnceJob() { |
| } |
| |
| @PostConstruct |
| public void initLockManager() throws Exception { |
| this.lockManager = injector.getInstance(LockManager.class); |
| if (lockManager != null) { |
| logger.info("LockManager injection successful"); |
| } else { |
| logger.error("LockManager injection unsuccessful"); |
| } |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.apache.usergrid.batch.Job#execute(org.apache.usergrid.batch.JobExecution) |
| */ |
| @Override |
| public void execute( JobExecution execution ) throws Exception { |
| |
| logger.info("Executing one-time job, LockManager is {}", lockManager == null ? "null" : "not null"); |
| String lockId = execution.getJobId().toString(); |
| |
| Lock lock = lockManager.createLock( emf.getManagementAppId(), String.format( "/jobs/%s", lockId ) ); |
| |
| // the job is still running somewhere else. Try again in getDelay() milliseconds |
| if ( !lock.tryLock( 0, TimeUnit.MILLISECONDS ) ) { |
| execution.delay( getDelay( execution ) ); |
| return; |
| } |
| |
| //if we get here we can proceed. Make sure we unlock no matter what. |
| try { |
| |
| doJob( execution ); |
| } |
| finally { |
| lock.unlock(); |
| } |
| } |
| |
| |
| /** Delegate the job execution to the subclass */ |
| protected abstract void doJob( JobExecution execution ) throws Exception; |
| |
| /** Get the delay for the next run if we can't acquire the lock */ |
| protected abstract long getDelay( JobExecution execution ) throws Exception; |
| } |