/*
    * Copyright 2002,2004 The Apache Software Foundation.
    *
    * 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.apache.commons.jelly.tags.xml;
  
  import org.apache.commons.jelly.JellyException;
  import org.apache.commons.jelly.JellyTagException;
  import org.apache.commons.jelly.TagSupport;
  import org.apache.commons.jelly.XMLOutput;
  import org.xml.sax.Attributes;
  import org.xml.sax.SAXException;
  import org.xml.sax.helpers.AttributesImpl;
  
  /*** A tag to produce an XML element which can contain other attributes
    * or elements like the <code>&lt;xsl:element&gt;</code> tag.
    *
    * @author James Strachan
    * @version $Revision: 219726 $
    */
  public class ElementTag extends TagSupport {
  
      /*** The namespace URI. */
      private String namespace;
  
      /*** The qualified name. */
      private String name;
  
      /*** The XML Attributes. */
      private AttributesImpl attributes = new AttributesImpl();
  
      /*** flag set if attributes are output. */
      private boolean outputAttributes;
  
      public ElementTag() {
      }
  
      /***
       * Sets the attribute of the given name to the specified value.
       *
       * @param name of the attribute
       * @param value of the attribute
       * @param uri namespace of the attribute
       * @throws JellyTagException if the start element has already been output.
       *   Attributes must be set on the outer element before any content
       *   (child elements or text) is output
       */
      public void setAttributeValue(String name, String value, String uri) throws JellyTagException {
          if (outputAttributes) {
              throw new JellyTagException(
                  "Cannot set the value of attribute: "
                  + name + " as we have already output the startElement() SAX event"
              );
          }
  
          // ### we'll assume that all attributes are in no namespace!
          // ### this is severely limiting!
          // ### we should be namespace aware
          // NAMESPACE FIXED:
          int idx = name.indexOf(':');
          final String localName = (idx >= 0)
              ? name.substring(idx + 1)
              : name;
          final String nsUri = (uri != null)
              ? uri
              : "";
  
          int index = attributes.getIndex(nsUri, localName);
          if (index >= 0) {
              attributes.removeAttribute(index);
          }
          // treat null values as no attribute
          if (value != null) {
              attributes.addAttribute(nsUri, localName, name, "CDATA", value);
          }
      }
  
      // Tag interface
      //-------------------------------------------------------------------------
      public void doTag(XMLOutput output) throws JellyTagException {
          int idx = name.indexOf(':');
          final String localName = (idx >= 0)
              ? name.substring(idx + 1)
              : name;
  
          outputAttributes = false;
  
          XMLOutput newOutput = new XMLOutput(output) {
 
             // add an initialize hook to the core content-generating methods
 
             public void startElement(
                 String uri,
                 String localName,
                 String qName,
                 Attributes atts)
                 throws SAXException {
                 initialize();
                 super.startElement(uri, localName, qName, atts);
             }
 
             public void endElement(String uri, String localName, String qName)
                 throws SAXException {
                 initialize();
                 super.endElement(uri, localName, qName);
             }
 
             public void characters(char[] ch, int start, int length) throws SAXException {
                 initialize();
                 super.characters(ch, start, length);
             }
 
             public void ignorableWhitespace(char[] ch, int start, int length)
                 throws SAXException {
                 initialize();
                 super.ignorableWhitespace(ch, start, length);
             }
 
             public void objectData(Object object)
                 throws SAXException {
                 initialize();
                 super.objectData(object);
             }
 
             public void processingInstruction(String target, String data)
                 throws SAXException {
                 initialize();
                 super.processingInstruction(target, data);
             }
 
             /***
              * Ensure that the outer start element is generated
              * before any content is output.
              */
             protected void initialize() throws SAXException {
                 if (!outputAttributes) {
                     super.startElement(namespace, localName, name, attributes);
                     outputAttributes = true;
                 }
             }
         };
 
         invokeBody(newOutput);
 
         try {
             if (!outputAttributes) {
                 output.startElement(namespace, localName, name, attributes);
                 outputAttributes = true;
             }
 
             output.endElement(namespace, localName, name);
             attributes.clear();
         } catch (SAXException e) {
             throw new JellyTagException(e);
         }
     }
 
     // Properties
     //-------------------------------------------------------------------------
 
     /***
      * @return the qualified name of the element
      */
     public String getName() {
         return name;
     }
 
     /***
      * Sets the qualified name of the element
      */
     public void setName(String name) {
         this.name = name;
     }
 
     /***
      * @return the namespace URI of the element
      */
     public String getURI() {
         return namespace;
     }
 
     /***
      * Sets the namespace URI of the element
      */
     public void setURI(String namespace) {
         this.namespace = namespace;
     }
 }