/* 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.engine.impl.bpmn.helper;
import org.activiti.engine.ActivitiIllegalArgumentException;
import org.activiti.engine.delegate.Expression;
import org.activiti.engine.delegate.event.ActivitiEntityEvent;
import org.activiti.engine.delegate.event.ActivitiEvent;
import org.activiti.engine.delegate.event.ActivitiEventListener;
import org.activiti.engine.impl.el.NoExecutionVariableScope;
/**
* An {@link ActivitiEventListener} implementation which resolves an expression
* to a delegate {@link ActivitiEventListener} instance and uses this for event notification.
*
* In case an entityClass was passed in the constructor, only events that are {@link ActivitiEntityEvent}'s
* that target an entity of the given type, are dispatched to the delegate.
*
* @author Frederik Heremans
*/
public class DelegateExpressionActivitiEventListener extends BaseDelegateEventListener {
protected Expression expression;
protected boolean failOnException = true;
public DelegateExpressionActivitiEventListener(Expression expression, Class> entityClass) {
this.expression = expression;
setEntityClass(entityClass);
}
@Override
public void onEvent(ActivitiEvent event) {
if(isValidEvent(event)) {
NoExecutionVariableScope scope = new NoExecutionVariableScope();
Object delegate = expression.getValue(scope);
if (delegate instanceof ActivitiEventListener) {
// Cache result of isFailOnException() from delegate-instance until next
// event is received. This prevents us from having to resolve the expression twice when
// an error occurs.
failOnException = ((ActivitiEventListener) delegate).isFailOnException();
// Call the delegate
((ActivitiEventListener) delegate).onEvent(event);
} else {
// Force failing, since the exception we're about to throw cannot be ignored, because it
// did not originate from the listener itself
failOnException = true;
throw new ActivitiIllegalArgumentException("Delegate expression " + expression
+ " did not resolve to an implementation of " + ActivitiEventListener.class.getName());
}
}
}
@Override
public boolean isFailOnException() {
return failOnException;
}
}