/* 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.application;
import java.util.Collections;
import java.util.Map;
import java.util.ServiceLoader;
import java.util.concurrent.Callable;
import java.util.logging.Logger;
import org.camunda.bpm.application.impl.DefaultElResolverLookup;
import org.camunda.bpm.container.RuntimeContainerDelegate;
import org.camunda.bpm.engine.delegate.ExecutionListener;
import org.camunda.bpm.engine.delegate.TaskListener;
import org.camunda.bpm.engine.impl.javax.el.BeanELResolver;
import org.camunda.bpm.engine.impl.javax.el.ELResolver;
import org.camunda.bpm.engine.impl.util.ClassLoaderUtil;
import org.camunda.bpm.engine.repository.DeploymentBuilder;
/**
* @author Daniel Meyer
*
*/
public abstract class AbstractProcessApplication implements ProcessApplicationInterface {
private final static Logger LOGGER = Logger.getLogger(AbstractProcessApplication.class.getName());
protected ELResolver processApplicationElResolver;
protected BeanELResolver processApplicationBeanElResolver;
protected boolean isDeployed = false;
// deployment /////////////////////////////////////////////////////
public void deploy() {
if(isDeployed) {
LOGGER.warning("Calling deploy() on process application that is already deployed.");
} else {
// deploy the application
RuntimeContainerDelegate.INSTANCE.get().deployProcessApplication(this);
isDeployed = true;
}
}
public void undeploy() {
if(!isDeployed) {
LOGGER.fine("Calling undeploy() on process application that is already undeployed.");
} else {
// delegate stopping of the process application to the runtime container.
RuntimeContainerDelegate.INSTANCE.get().undeployProcessApplication(this);
isDeployed = false;
}
}
public void createDeployment(String processArchiveName, DeploymentBuilder deploymentBuilder) {
// default implementation does nothing
}
// Runtime ////////////////////////////////////////////
public String getName() {
Class<? extends AbstractProcessApplication> processApplicationClass = getClass();
String name = null;
ProcessApplication annotation = processApplicationClass.getAnnotation(ProcessApplication.class);
if(annotation != null) {
name = annotation.value();
}
if(name == null || name.length()==0) {
name = autodetectProcessApplicationName();
}
return name;
}
/**
* Override this method to autodetect an application name in case the
* {@link ProcessApplication} annotation was used but without parameter.
*/
protected abstract String autodetectProcessApplicationName();
public <T> T execute(Callable<T> callable) throws ProcessApplicationExecutionException {
ClassLoader originalClassloader = ClassLoaderUtil.getContextClassloader();
ClassLoader processApplicationClassloader = getProcessApplicationClassloader();
try {
ClassLoaderUtil.setContextClassloader(processApplicationClassloader);
return callable.call();
} catch(Exception e) {
throw new ProcessApplicationExecutionException(e);
} finally {
ClassLoaderUtil.setContextClassloader(originalClassloader);
}
}
public ClassLoader getProcessApplicationClassloader() {
// the default implementation uses the classloader that loaded
// the application-provided subclass of this class.
return ClassLoaderUtil.getClassloader(getClass());
}
public ProcessApplicationInterface getRawObject() {
return this;
}
public Map<String, String> getProperties() {
return Collections.<String, String>emptyMap();
}
public ELResolver getElResolver() {
if(processApplicationElResolver == null) {
synchronized (this) {
if(processApplicationElResolver == null) {
processApplicationElResolver = initProcessApplicationElResolver();
}
}
}
return processApplicationElResolver;
}
public BeanELResolver getBeanElResolver() {
if(processApplicationBeanElResolver == null) {
synchronized (this) {
if(processApplicationBeanElResolver == null) {
processApplicationBeanElResolver = new BeanELResolver();
}
}
}
return processApplicationBeanElResolver;
}
/**
* <p>Initializes the process application provided ElResolver. This implementation uses the
* Java SE {@link ServiceLoader} facilities for resolving implementations of {@link ProcessApplicationElResolver}.</p>
*
* <p>If you want to provide a custom implementation in your application, place a file named
* <code>META-INF/org.camunda.bpm.application.ProcessApplicationElResolver</code> inside your application
* which contains the fully qualified classname of your implementation. Or simply override this method.</p>
*
* @return the process application ElResolver.
*/
protected ELResolver initProcessApplicationElResolver() {
return DefaultElResolverLookup.lookupResolver(this);
}
public ExecutionListener getExecutionListener() {
return null;
}
public TaskListener getTaskListener() {
return null;
}
}