/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jbpm.graph.node;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.dom4j.Element;
import org.jbpm.JbpmConfiguration;
import org.jbpm.JbpmException;
import org.jbpm.graph.def.Node;
import org.jbpm.graph.def.Transition;
import org.jbpm.graph.exe.ExecutionContext;
import org.jbpm.instantiation.Delegation;
import org.jbpm.jpdl.el.impl.JbpmExpressionEvaluator;
import org.jbpm.jpdl.xml.JpdlXmlReader;
/**
* decision node.
*/
public class Decision extends Node {
static final long serialVersionUID = 1L;
List<DecisionCondition> decisionConditions = null;
Delegation decisionDelegation = null;
String decisionExpression = null;
public Decision() {
}
public Decision(String name) {
super(name);
}
@Override
public NodeType getNodeType() {
return NodeType.Decision;
}
public void read(Element decisionElement, JpdlXmlReader jpdlReader) {
String expression = decisionElement.attributeValue("expression");
Element decisionHandlerElement = decisionElement.element("handler");
if (expression != null) {
decisionExpression = expression;
}
else if (decisionHandlerElement != null) {
decisionDelegation = new Delegation();
decisionDelegation.read(decisionHandlerElement, jpdlReader);
}
}
public void execute(ExecutionContext executionContext) {
Transition transition = null;
// set context class loader correctly for delegation class
// (https://jira.jboss.org/jira/browse/JBPM-1448)
Thread currentThread = Thread.currentThread();
ClassLoader contextClassLoader = currentThread.getContextClassLoader();
currentThread.setContextClassLoader(JbpmConfiguration.getProcessClassLoader(executionContext.getProcessDefinition()));
try {
if (decisionDelegation != null) {
DecisionHandler decisionHandler = (DecisionHandler) decisionDelegation.getInstance();
if (decisionHandler == null)
decisionHandler = (DecisionHandler) decisionDelegation.instantiate();
String transitionName = decisionHandler.decide(executionContext);
transition = getLeavingTransition(transitionName);
if (transition == null) {
throw new JbpmException("decision '"
+ name
+ "' selected non existing transition '"
+ transitionName
+ "'");
}
}
else if (decisionExpression != null) {
Object result = JbpmExpressionEvaluator.evaluate(decisionExpression, executionContext);
if (result == null) {
throw new JbpmException("decision expression '" + decisionExpression + "' returned null");
}
String transitionName = result.toString();
transition = getLeavingTransition(transitionName);
if (transition == null) {
throw new JbpmException("decision '"
+ name
+ "' selected non existing transition '"
+ transitionName
+ "'");
}
}
else if (decisionConditions != null && !decisionConditions.isEmpty()) {
// backwards compatible mode based on separate DecisionCondition's
for (DecisionCondition decisionCondition : decisionConditions) {
Object result = JbpmExpressionEvaluator.evaluate(decisionCondition.getExpression(),
executionContext);
if (Boolean.TRUE.equals(result)) {
String transitionName = decisionCondition.getTransitionName();
transition = getLeavingTransition(transitionName);
if (transition != null) break;
}
}
}
else {
// new mode based on conditions in the transition itself
for (Transition candidate : leavingTransitions) {
String conditionExpression = candidate.getCondition();
if (conditionExpression != null) {
Object result = JbpmExpressionEvaluator.evaluate(conditionExpression, executionContext);
if (Boolean.TRUE.equals(result)) {
transition = candidate;
break;
}
}
}
}
}
catch (Exception exception) {
raiseException(exception, executionContext);
if (!equals(executionContext.getNode())) {
return;
}
}
finally {
currentThread.setContextClassLoader(contextClassLoader);
}
if (transition == null) {
transition = getDefaultLeavingTransition();
if (transition == null)
throw new JbpmException("decision cannot select transition: " + this);
log.debug("decision did not select transition, taking default " + transition);
}
// since the decision node evaluates condition expressions, the condition of the
// taken transition will always be met. therefore we can safely turn off
// the standard condition enforcement in the transitions after a decision node.
transition.removeConditionEnforcement();
log.debug("decision '" + name + "' is taking " + transition);
executionContext.leaveNode(transition);
}
public List<DecisionCondition> getDecisionConditions() {
return decisionConditions;
}
public void setDecisionDelegation(Delegation decisionDelegation) {
this.decisionDelegation = decisionDelegation;
}
private static Log log = LogFactory.getLog(Decision.class);
}