/* 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.camunda.bpm.engine.impl.jobexecutor;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.camunda.bpm.engine.impl.ProcessEngineImpl;
import org.camunda.bpm.engine.impl.cmd.AcquireJobsCmd;
import org.camunda.bpm.engine.impl.interceptor.Command;
import org.camunda.bpm.engine.impl.interceptor.CommandExecutor;
import org.camunda.bpm.engine.runtime.Job;
/**
* <p>Interface to the component responsible for performing
* background work ({@link Job Jobs}).</p>
*
* <p>The {@link JobExecutor} is capable of dispatching to multiple process engines,
* ie. multiple process engines can share a single Thread Pool for performing Background
* Work. </p>
*
* <p>In clustered situations, you can have multiple Job Executors running against the
* same queue + pending job list.</p>
*
* @author Daniel Meyer
*/
public abstract class JobExecutor {
private static Logger log = Logger.getLogger(JobExecutor.class.getName());
protected String name = "JobExecutor["+getClass().getName()+"]";
protected List<ProcessEngineImpl> processEngines = new CopyOnWriteArrayList<ProcessEngineImpl>();
protected Command<AcquiredJobs> acquireJobsCmd;
protected AcquireJobsRunnable acquireJobsRunnable;
protected RejectedJobsHandler rejectedJobsHandler;
protected Thread jobAcquisitionThread;
protected boolean isAutoActivate = false;
protected boolean isActive = false;
protected int maxJobsPerAcquisition = 3;
protected int waitTimeInMillis = 5 * 1000;
protected String lockOwner = UUID.randomUUID().toString();
protected int lockTimeInMillis = 5 * 60 * 1000;
public void start() {
if (isActive) {
return;
}
log.info("Starting up the JobExecutor["+getClass().getName()+"].");
ensureInitialization();
startExecutingJobs();
isActive = true;
}
public synchronized void shutdown() {
if (!isActive) {
return;
}
log.info("Shutting down the JobExecutor["+getClass().getName()+"].");
acquireJobsRunnable.stop();
stopExecutingJobs();
ensureCleanup();
isActive = false;
}
protected void ensureInitialization() {
acquireJobsCmd = new AcquireJobsCmd(this);
acquireJobsRunnable = new SequentialJobAcquisitionRunnable(this);
}
protected void ensureCleanup() {
acquireJobsCmd = null;
acquireJobsRunnable = null;
}
public void jobWasAdded() {
if(isActive) {
acquireJobsRunnable.jobWasAdded();
}
}
public synchronized void registerProcessEngine(ProcessEngineImpl processEngine) {
processEngines.add(processEngine);
// when we register the first process engine, start the jobexecutor
if(processEngines.size() == 1 && isAutoActivate) {
start();
}
}
public synchronized void unregisterProcessEngine(ProcessEngineImpl processEngine) {
processEngines.remove(processEngine);
// if we unregister the last process engine, auto-shutdown the jobexecutor
if(processEngines.isEmpty() && isActive) {
shutdown();
}
}
protected abstract void startExecutingJobs();
protected abstract void stopExecutingJobs();
public abstract void executeJobs(List<String> jobIds, ProcessEngineImpl processEngine);
/**
* Deprecated: use {@link #executeJobs(List, ProcessEngineImpl)} instead
* @param jobIds
*/
@Deprecated
public void executeJobs(List<String> jobIds) {
if(!processEngines.isEmpty()) {
executeJobs(jobIds, processEngines.get(0));
}
}
// getters and setters //////////////////////////////////////////////////////
public List<ProcessEngineImpl> getProcessEngines() {
return processEngines;
}
/**
* Deprecated: use {@link #getProcessEngines()} instead
*/
@Deprecated
public CommandExecutor getCommandExecutor() {
if(processEngines.isEmpty()) {
return null;
} else {
return processEngines.get(0).getProcessEngineConfiguration().getCommandExecutorTxRequired();
}
}
/**
* Deprecated: use {@link #registerProcessEngine(ProcessEngineImpl)} instead
* @param commandExecutorTxRequired
*/
@Deprecated
public void setCommandExecutor(CommandExecutor commandExecutorTxRequired) {
}
public int getWaitTimeInMillis() {
return waitTimeInMillis;
}
public void setWaitTimeInMillis(int waitTimeInMillis) {
this.waitTimeInMillis = waitTimeInMillis;
}
public int getLockTimeInMillis() {
return lockTimeInMillis;
}
public void setLockTimeInMillis(int lockTimeInMillis) {
this.lockTimeInMillis = lockTimeInMillis;
}
public String getLockOwner() {
return lockOwner;
}
public void setLockOwner(String lockOwner) {
this.lockOwner = lockOwner;
}
public boolean isAutoActivate() {
return isAutoActivate;
}
public void setProcessEngines(List<ProcessEngineImpl> processEngines) {
this.processEngines = processEngines;
}
public void setAutoActivate(boolean isAutoActivate) {
this.isAutoActivate = isAutoActivate;
}
public int getMaxJobsPerAcquisition() {
return maxJobsPerAcquisition;
}
public void setMaxJobsPerAcquisition(int maxJobsPerAcquisition) {
this.maxJobsPerAcquisition = maxJobsPerAcquisition;
}
public String getName() {
return name;
}
public Command<AcquiredJobs> getAcquireJobsCmd() {
return acquireJobsCmd;
}
public void setAcquireJobsCmd(Command<AcquiredJobs> acquireJobsCmd) {
this.acquireJobsCmd = acquireJobsCmd;
}
public boolean isActive() {
return isActive;
}
public RejectedJobsHandler getRejectedJobsHandler() {
return rejectedJobsHandler;
}
public void setRejectedJobsHandler(RejectedJobsHandler rejectedJobsHandler) {
this.rejectedJobsHandler = rejectedJobsHandler;
}
protected void startJobAcquisitionThread() {
if (jobAcquisitionThread == null) {
jobAcquisitionThread = new Thread(acquireJobsRunnable, getName());
jobAcquisitionThread.start();
}
}
protected void stopJobAcquisitionThread() {
try {
jobAcquisitionThread.join();
} catch (InterruptedException e) {
log.log(
Level.WARNING,
"Interrupted while waiting for the job Acquisition thread to terminate",
e);
}
jobAcquisitionThread = null;
}
public AcquireJobsRunnable getAcquireJobsRunnable() {
return acquireJobsRunnable;
}
}