/* 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.activiti.cdi.impl;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
import java.util.ServiceLoader;
import javax.enterprise.event.Observes;
import javax.enterprise.inject.spi.AfterBeanDiscovery;
import javax.enterprise.inject.spi.AfterDeploymentValidation;
import javax.enterprise.inject.spi.BeanManager;
import javax.enterprise.inject.spi.BeforeBeanDiscovery;
import javax.enterprise.inject.spi.BeforeShutdown;
import javax.enterprise.inject.spi.Extension;
import org.activiti.cdi.annotation.BusinessProcessScoped;
import org.activiti.cdi.impl.context.BusinessProcessContext;
import org.activiti.cdi.impl.util.ActivitiServices;
import org.activiti.cdi.impl.util.BeanManagerLookup;
import org.activiti.cdi.impl.util.ProgrammaticBeanLookup;
import org.activiti.cdi.spi.ProcessEngineLookup;
import org.activiti.engine.ActivitiException;
import org.activiti.engine.ProcessEngine;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* CDI-Extension registering a custom context for {@link BusinessProcessScoped}
* beans.
*
* Also starts / stops the activiti {@link ProcessEngine} and deploys all
* processes listed in the 'processes.xml'-file.
*
* @author Daniel Meyer
*/
public class ActivitiExtension implements Extension {
private static Logger logger = LoggerFactory.getLogger(ActivitiExtension.class);
private ProcessEngineLookup processEngineLookup;
public void beforeBeanDiscovery(@Observes final BeforeBeanDiscovery event) {
event.addScope(BusinessProcessScoped.class, true, true);
}
public void afterBeanDiscovery(@Observes AfterBeanDiscovery event, BeanManager manager) {
BeanManagerLookup.localInstance = manager;
event.addContext(new BusinessProcessContext(manager));
}
public void afterDeploymentValidation(@Observes AfterDeploymentValidation event, BeanManager beanManager) {
try {
logger.info("Initializing activiti-cdi.");
// initialize the process engine
ProcessEngine processEngine = lookupProcessEngine(beanManager);
// deploy the processes if engine was set up correctly
deployProcesses(processEngine);
} catch (Exception e) {
// interpret engine initialization problems as definition errors
event.addDeploymentProblem(e);
}
}
protected ProcessEngine lookupProcessEngine(BeanManager beanManager) {
ServiceLoader<ProcessEngineLookup> processEngineServiceLoader = ServiceLoader.load(ProcessEngineLookup.class);
Iterator<ProcessEngineLookup> serviceIterator = processEngineServiceLoader.iterator();
List<ProcessEngineLookup> discoveredLookups = new ArrayList<ProcessEngineLookup>();
while (serviceIterator.hasNext()) {
ProcessEngineLookup serviceInstance = (ProcessEngineLookup) serviceIterator.next();
discoveredLookups.add(serviceInstance);
}
Collections.sort(discoveredLookups, new Comparator<ProcessEngineLookup>() {
public int compare(ProcessEngineLookup o1, ProcessEngineLookup o2) {
return (-1)*((Integer)o1.getPrecedence()).compareTo(o2.getPrecedence());
}
});
ProcessEngine processEngine = null;
for (ProcessEngineLookup processEngineLookup : discoveredLookups) {
processEngine = processEngineLookup.getProcessEngine();
if(processEngine != null) {
this.processEngineLookup = processEngineLookup;
logger.debug("ProcessEngineLookup service {} returned process engine.", processEngineLookup.getClass());
break;
} else {
logger.debug("ProcessEngineLookup service {} retuned 'null' value.", processEngineLookup.getClass());
}
}
if(processEngineLookup == null) {
throw new ActivitiException("Could not find an implementation of the org.activiti.cdi.spi.ProcessEngineLookup service " +
"returning a non-null processEngine. Giving up.");
}
ActivitiServices activitiServices = ProgrammaticBeanLookup.lookup(ActivitiServices.class, beanManager);
activitiServices.setProcessEngine(processEngine);
return processEngine;
}
private void deployProcesses(ProcessEngine processEngine) {
new ProcessDeployer(processEngine).deployProcesses();
}
public void beforeShutdown(@Observes BeforeShutdown event) {
if(processEngineLookup != null) {
processEngineLookup.ungetProcessEngine();
processEngineLookup = null;
}
logger.info("Shutting down activiti-cdi");
}
}