/*

  * Copyright 2007-2010 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;

 import java.util.ArrayList;

 import java.util.List;

 import org.xml.sax.Attributes;

 import org.xml.sax.SAXException;

 import org.xml.sax.helpers.XMLFilterImpl;

 /**

  * This XML Filter is used to eliminate unwanted elements from a pre-1.0.3 Group XML document.  

  * As an example:

  *

  *   -- Example from GroupXmlImportTest.xml as filtered by GroupNamespaceURIEliminationFilterPOC -- 

  *   <members>

  *       <principalName>ewestfal</principalName>

  *       <principalName>rkirkend</principalName>

  *       <principalId>2015</principalId>

  *       <groupName>

  *           <name>TestWorkgroup</name>

  *           <namespace>KR-WKFLW</namespace>

  *        </groupName>

  *   </members>

  *   

  *   -- Resulting transformation --

  *   <members>

  *       <principalName>ewestfal</principalName>

  *       <principalName>rkirkend</principalName>

  *       <principalId>2015</principalId>

  *   </members>

  * 

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

  *

  */

 public class GroupNamespaceURIEliminationFilterPOC extends XMLFilterImpl {

         // The URI of a Group 1.0.3 schema 

     public static final String GROUP_URI="http://rice.kuali.org/xsd/kim/group";

         // The List containing elements which will be eliminated

         private List<String> elementEliminationList;

         // A flag to determine if the current element is in the elimination list

         private boolean eliminatedElement = false;

         // The list which helps keep track of where we are in the XML 

         // hierarchy as the stream is being processed

         private List<String> groupXmlStack = new ArrayList<String>();

         public GroupNamespaceURIEliminationFilterPOC(){

                 super();

                 // Initialize the element elimination list

                 setElementEliminationList();

         }

     public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {

                 // Push the element onto the stack

                 if (groupXmlStack.isEmpty()){

                         // Push the root element without onto the stack without special formatting

                         groupXmlStack.add(localName);

                 }

                 else {

                         // Push a child element by appending localName to the value of the top element in the stack

                         groupXmlStack.add(groupXmlStack.get(groupXmlStack.size()-1) + "." + localName);

                 }

                 // Fetch the current element from the top of the stack

                 String currentElement = groupXmlStack.get(groupXmlStack.size()-1);

                 // Eliminate elements of concern:

                 if (elementEliminationList.contains(currentElement)) {

                         // Flag the current element for elimination

                         eliminatedElement = true;

                 }

                 // Perform normal parsing

                 else {

                         eliminatedElement = false;

                         super.startElement(GROUP_URI, localName, qName, atts);

                 }

     }

     public void endElement(String uri, String localName, String qName) throws SAXException {

                 // Fetch the current element from the top of the stack

                 String currentElement = groupXmlStack.get(groupXmlStack.size()-1);

                 // Eliminate elements of concern:

                 if (elementEliminationList.contains(currentElement)) {

                         // Flag the current element for elimination

                         eliminatedElement = true;

                 }

                 // Perform normal parsing behavior

                 else {

                         eliminatedElement = false;

                         super.endElement(GROUP_URI, localName, qName);

                 }

                 // Pop the element from the stack if it's not empty

                 if (!groupXmlStack.isEmpty()){

                         groupXmlStack.remove(currentElement);                        

                 }

     }

     /*

      * Override the characters() method using an empty implementation so that the text

      * inside of each eliminated element is also eliminated. 

      */

     @Override

     public void characters (char[] ch, int start, int length) throws SAXException {        

             if (!eliminatedElement) {

                     super.characters(ch, start, length);

             }

     }

         /*

          * Build a List defining which elements we intend to eliminate .

          * The values in this List are "hierarchically-qualified" representations of the elements of concern.

          * 

          * For example, if "group" is a child of "groups", which is in turn a child of the root

          * element "data", then it is represented as "data.groups.group" in the Map.

          */

         private void setElementEliminationList() {

                 List<String> elementEliminationList = new ArrayList<String>();

                 elementEliminationList.add("data");

                 elementEliminationList.add("data.groups");

                 elementEliminationList.add("data.groups.group.members.groupName");

                 elementEliminationList.add("data.groups.group.members.groupName.name");

                 elementEliminationList.add("data.groups.group.members.groupName.namespace");

                 this.elementEliminationList = elementEliminationList;

         }

 }