/*

  * 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 org.apache.commons.lang.StringEscapeUtils;

 import org.kuali.rice.core.api.util.ConcreteKeyValue;

 import org.kuali.rice.core.api.util.KeyValue;

 import org.xml.sax.Attributes;

 import org.xml.sax.SAXException;

 import org.xml.sax.helpers.XMLFilterImpl;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * This abstract class handles the xml stack of elements and makes

  * it easier to run a transformation on certain elements.

  * 

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

  *

  */

 public abstract class AbstractTransformationFilter extends XMLFilterImpl {

         // 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>();

         /**

          * 

          * This method allows you to modify the element passed in.  The returned element

          * will be pushed into a "super.startElement(uri, localName, qName, atts)" call.

          * 

          * @param currentElement

          * @return

          */

         public abstract CurrentElement transformStartElement(CurrentElement currentElement) throws SAXException;

         /**

          * 

          * This method allows you to modify the element passed in.  The returned element

          * will be pushed into a "super.endElement(uri, localName, qName" call.

          * 

          * @param currentElement

          * @return

          */

         public abstract CurrentElement transformEndElement(CurrentElement currentElement) throws SAXException;

         /*

          * Build a Map that maps elements we intend to transform to their corresponding transformed value.

          * The keys in this Map 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.

          */

         public abstract List<KeyValue> getElementTransformationList();        

         /**

          * 

          * This method returns the element that we should start transforming at.

          * So, if we had:

          * <data>

          *   <groups>

          *     <group>

          *     

          * We might want to start transforming at the group level. 

          * In that case the startingElement = "group"

          * 

          * @return

          */

         public abstract String getStartingElementPath();

         @Override

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

                 // Push the element onto the stack

                 if (groupXmlStack.isEmpty()){                        

                                 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 currentElementKey = groupXmlStack.get(groupXmlStack.size()-1);

                 CurrentElement currentElement = new CurrentElement(currentElementKey,uri, localName, qName, atts);

                 // Transform elements of concern:

                 if (getElementTransformationList().contains(new ConcreteKeyValue(getTrimmedCurrentElementKey(currentElementKey), uri))){

                         CurrentElement transformedElement = this.transformStartElement(currentElement);                        

                         super.startElement(transformedElement.getUri(), transformedElement.getLocalName(), transformedElement.getqName(), transformedElement.getAttributes());

                 }

                 else {

                         // Pass other elements through as they are

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

                 }

     }

         protected String getTrimmedCurrentElementKey(String currentElementKey){

                 return currentElementKey.replaceFirst(StringEscapeUtils.escapeJava(this.getStartingElementPath()+"."), "");

         }

     @Override

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

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

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

                 CurrentElement currentElement = new CurrentElement(currentElementKey,uri, localName, qName);

                 if (getElementTransformationList().contains(new ConcreteKeyValue(getTrimmedCurrentElementKey(currentElementKey), uri))){

                         CurrentElement transformedElement = this.transformEndElement(currentElement);                        

                         super.endElement(transformedElement.getUri(), transformedElement.getLocalName(), transformedElement.getqName());

                 }                

                 else {

                         // Pass other elements through as they are

                         super.endElement(uri, localName, qName);

                 }

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

                 if (!groupXmlStack.isEmpty()){

                         groupXmlStack.remove(currentElementKey);                        

                 }

     }

         public class CurrentElement {

                 String nameKey;

                 String uri;

                 String localName; 

                 String qName; 

                 Attributes attributes;

                 public CurrentElement(){}

                 public CurrentElement(String nameKey, String uri, String localName,

                                 String qName) {

                         super();

                         this.nameKey = nameKey;

                         this.uri = uri;

                         this.localName = localName;

                         this.qName = qName;

                 }

                 public CurrentElement(String nameKey,String uri, String localName, String qName,

                                 Attributes attributes) {

                         super();

                         this.nameKey = nameKey;

                         this.uri = uri;

                         this.localName = localName;

                         this.qName = qName;

                         this.attributes = attributes;

                 }

                 public String getUri() {

                         return this.uri;

                 }

                 public void setUri(String uri) {

                         this.uri = uri;

                 }

                 public String getLocalName() {

                         return this.localName;

                 }

                 public void setLocalName(String localName) {

                         this.localName = localName;

                 }

                 public String getqName() {

                         return this.qName;

                 }

                 public void setqName(String qName) {

                         this.qName = qName;

                 }

                 public Attributes getAttributes() {

                         return this.attributes;

                 }

                 public void setAttributes(Attributes attributes) {

                         this.attributes = attributes;

                 }

                 public String getNameKey() {

                         return this.nameKey;

                 }

                 public void setNameKey(String nameKey) {

                         this.nameKey = nameKey;

                 }                

         }

 }