/**

  * Copyright 2005-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.kew.xml.xstream;

 import java.util.List;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathExpressionException;

 import javax.xml.xpath.XPathFunction;

 import javax.xml.xpath.XPathFunctionException;

 import org.w3c.dom.Node;

 /**

  * An XPathFunction which will run XStream safe XPath queries.

  * 

  * @see XStreamSafeEvaluator

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class XStreamSafeSearchFunction implements XPathFunction {

         private final Node rootNode;

         private XPath xpath;

         private static XStreamSafeEvaluator evaluator = new XStreamSafeEvaluator();

         public XStreamSafeSearchFunction(Node rootNode, XPath xpath) {

                 this.rootNode = rootNode;

                 this.xpath = xpath;

         }

         public Object evaluate(List parameters) throws XPathFunctionException {

                 String xPathExpression = getXPathExpressionParameter(parameters);

                 evaluator.setXpath(xpath);

                 //Node rootSearchNode = getRootSearchNodeParameter(parameters);

                 try {

                         return evaluator.evaluate(xPathExpression, rootNode);

                 } catch (XPathExpressionException e) {

                         throw new XPathFunctionException(e);

                 }

         }

         private String getXPathExpressionParameter(List parameters) throws XPathFunctionException {

                 if (parameters.size() < 1) {

                         throw new XPathFunctionException("First parameter must be an XPath expression.");

                 }

                 if (!(parameters.get(0) instanceof String)) {

                         throw new XPathFunctionException("First parameter must be an XPath expression String");

                 }

                 return (String)parameters.get(0);

         }

         public XPath getXpath() {

                 return xpath;

         }

         public void setXpath(XPath xpath) {

                 this.xpath = xpath;

         }

         /*private Node getRootSearchNodeParameter(List parameters) throws XPathFunctionException {

                 if (parameters.size() < 2) {

                         throw new XPathFunctionException("Second parameter should be root node and is required");

                 }

                 System.out.println(parameters.get(1));

                 if (!(parameters.get(1) instanceof Node)) {

                         throw new XPathFunctionException("Second parameter should be an instance of Node (try using the root() XPath function).");

                 }

                 return (Node)parameters.get(1);

         }*/

 }