/* 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.bpmn.behavior;
import java.util.Iterator;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.camunda.bpm.engine.ProcessEngineException;
import org.camunda.bpm.engine.impl.Condition;
import org.camunda.bpm.engine.impl.bpmn.parser.BpmnParse;
import org.camunda.bpm.engine.impl.pvm.PvmTransition;
import org.camunda.bpm.engine.impl.pvm.delegate.ActivityExecution;
/**
* implementation of the Exclusive Gateway/XOR gateway/exclusive data-based gateway
* as defined in the BPMN specification.
*
* @author Joram Barrez
*/
public class ExclusiveGatewayActivityBehavior extends GatewayActivityBehavior {
private static Logger log = Logger.getLogger(ExclusiveGatewayActivityBehavior.class.getName());
/**
* The default behaviour of BPMN, taking every outgoing sequence flow
* (where the condition evaluates to true), is not valid for an exclusive
* gateway.
*
* Hence, this behaviour is overriden and replaced by the correct behavior:
* selecting the first sequence flow which condition evaluates to true
* (or which hasn't got a condition) and leaving the activity through that
* sequence flow.
*
* If no sequence flow is selected (ie all conditions evaluate to false),
* then the default sequence flow is taken (if defined).
*/
@Override
protected void leave(ActivityExecution execution) {
if (log.isLoggable(Level.FINE)) {
log.fine("Leaving activity '" + execution.getActivity().getId() + "'");
}
PvmTransition outgoingSeqFlow = null;
String defaultSequenceFlow = (String) execution.getActivity().getProperty("default");
Iterator<PvmTransition> transitionIterator = execution.getActivity().getOutgoingTransitions().iterator();
while (outgoingSeqFlow == null && transitionIterator.hasNext()) {
PvmTransition seqFlow = transitionIterator.next();
Condition condition = (Condition) seqFlow.getProperty(BpmnParse.PROPERTYNAME_CONDITION);
if ( (condition == null && (defaultSequenceFlow == null || !defaultSequenceFlow.equals(seqFlow.getId())) )
|| (condition != null && condition.evaluate(execution)) ) {
if (log.isLoggable(Level.FINE)) {
log.fine("Sequence flow '" + seqFlow.getId() + " '"
+ "selected as outgoing sequence flow.");
}
outgoingSeqFlow = seqFlow;
}
}
if (outgoingSeqFlow != null) {
execution.take(outgoingSeqFlow);
} else {
if (defaultSequenceFlow != null) {
PvmTransition defaultTransition = execution.getActivity().findOutgoingTransition(defaultSequenceFlow);
if (defaultTransition != null) {
execution.take(defaultTransition);
} else {
throw new ProcessEngineException("Default sequence flow '" + defaultSequenceFlow + "' not found");
}
} else {
//No sequence flow could be found, not even a default one
throw new ProcessEngineException("No outgoing sequence flow of the exclusive gateway '"
+ execution.getActivity().getId() + "' could be selected for continuing the process");
}
}
}
}