/*
* 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.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.dom4j.Element;
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;
import org.jbpm.jpdl.xml.Parsable;
/**
* decision node.
*/
public class Decision extends Node implements Parsable {
static final String NEWLINE = System.getProperty("line.separator");
static final String DECISION_CONDITION_RESULT = "decision_condition_result";
static final long serialVersionUID = 1L;
List decisionConditions = null;
Delegation decisionDelegation = null;
String decisionExpression = null;
public Decision() {
}
public Decision(String name) {
super(name);
}
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);
}
Iterator iter = decisionElement.elementIterator("transition");
while (iter.hasNext()) {
Element transitionElement = (Element) iter.next();
Element conditionElement = transitionElement.element("condition");
if (conditionElement!=null) {
String conditionExpression = getConditionExpression(conditionElement);
if (conditionExpression!=null) {
String transitionName = transitionElement.attributeValue("name");
if (decisionConditions==null) {
decisionConditions = new ArrayList();
}
decisionConditions.add(new DecisionCondition(transitionName, conditionExpression));
}
}
}
}
String getConditionExpression(Element conditionElement) {
String expression = conditionElement.attributeValue("expression");
if (expression!=null) {
return expression;
} else {
return conditionElement.getText();
}
}
public void execute(ExecutionContext executionContext) {
String transitionName = null;
try {
if (decisionDelegation!=null) {
DecisionHandler decisionHandler = (DecisionHandler) decisionDelegation.instantiate();
transitionName = decisionHandler.decide(executionContext);
} else if (decisionExpression!=null) {
Object result = JbpmExpressionEvaluator.evaluate(decisionExpression, executionContext);
if (result==null) {
throw new JbpmException("decision expression '"+decisionExpression+"' returned null");
}
transitionName = result.toString();
} else {
Iterator iter = decisionConditions.iterator();
while (iter.hasNext() && (transitionName==null)) {
DecisionCondition decisionCondition = (DecisionCondition) iter.next();
Object result = JbpmExpressionEvaluator.evaluate(decisionCondition.getExpression(), executionContext);
if (Boolean.TRUE.equals(result)) {
transitionName = decisionCondition.getTransitionName();
}
}
if (transitionName==null) {
getDefaultLeavingTransition().getName();
}
}
} catch (Throwable exception) {
raiseException(exception, executionContext);
}
Transition transition = null;
if (transitionName!=null) {
log.debug("selected transition name '"+transitionName+"'");
transition = getLeavingTransition(transitionName);
} else {
log.debug("no transition name selected: taking default leaving transition");
transition = getDefaultLeavingTransition();
}
if (transition==null) {
throw new JbpmException("decision '"+name+"' selected non existing transition '"+transitionName+"'" );
}
executionContext.leaveNode(transition);
}
/*
String createDecisionExpression() {
// String decision_condition_result = null;
// if (condition1) {
// decision_condition_result = transitionName1;
// } else if (condition2) {
// decision_condition_result = transitionName2;
// }
StringBuffer stringBuffer = new StringBuffer();
stringBuffer.append("String selectedTransitionName = null; "+NEWLINE);
boolean isFirst = true;
Iterator iter = decisionConditions.iterator();
while (iter.hasNext()) {
DecisionCondition decisionCondition = (DecisionCondition) iter.next();
if (isFirst) {
isFirst = false;
} else {
stringBuffer.append(" else ");
}
stringBuffer.append("if (");
stringBuffer.append(decisionCondition.expression);
stringBuffer.append(") {");
stringBuffer.append(NEWLINE);
stringBuffer.append(" ");
stringBuffer.append(DECISION_CONDITION_RESULT);
stringBuffer.append(" = \"");
stringBuffer.append(decisionCondition.transitionName);
stringBuffer.append("\";");
stringBuffer.append(NEWLINE);
stringBuffer.append("}");
}
return stringBuffer.toString();
}
*/
public List getDecisionConditions() {
return decisionConditions;
}
private static Log log = LogFactory.getLog(Decision.class);
}