/*
Copyright 2010 Intalio Inc
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.jbpm.process.instance.impl;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.List;
import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import javax.xml.xpath.XPathFunction;
import javax.xml.xpath.XPathFunctionException;
import javax.xml.xpath.XPathFunctionResolver;
import javax.xml.xpath.XPathVariableResolver;
import org.drools.runtime.process.ProcessContext;
public class XPATHReturnValueEvaluator
implements
ReturnValueEvaluator,
Externalizable {
private static final long serialVersionUID = 510l;
private String expression;
private String id;
public XPATHReturnValueEvaluator() {
}
public XPATHReturnValueEvaluator(final String expression,
final String id) {
this.expression = expression;
this.id = id;
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
// id = in.readUTF();
expression = (String) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
// out.writeUTF( id );
out.writeObject(expression);
}
public String getDialect() {
return this.id;
}
public Object evaluate(final ProcessContext context) throws Exception {
XPathFactory factory = XPathFactory.newInstance();
XPath xpathEvaluator = factory.newXPath();
xpathEvaluator.setXPathFunctionResolver(
new XPathFunctionResolver() {
public XPathFunction resolveFunction(QName functionName, int arity)
{
String localName = functionName.getLocalPart();
if ("getVariable".equals(localName)) {
return new GetVariableData();
}
else {
throw new RuntimeException("Unknown BPMN function: " + functionName);
}
}
class GetVariableData implements XPathFunction {
public Object evaluate(List args) throws XPathFunctionException {
String varname = (String) args.get(0);
return context.getVariable(varname);
}
}
}
);
xpathEvaluator.setXPathVariableResolver(new XPathVariableResolver() {
public Object resolveVariable(QName variableName) {
return context.getVariable(variableName.getLocalPart());
}
});
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
return xpathEvaluator.evaluate(this.expression, builder.newDocument(), XPathConstants.BOOLEAN);
}
public String toString() {
return this.expression;
}
}