/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.
 */
/*
 * $Id$
 */
package org.apache.xalan.templates;

import javax.xml.transform.TransformerException;

import org.apache.xalan.res.XSLTErrorResources;
import org.apache.xalan.transformer.TransformerImpl;

/**
 * Implement xsl:comment.
 * <pre>
 * <!ELEMENT xsl:comment %char-template;>
 * <!ATTLIST xsl:comment %space-att;>
 * </pre>
 * @see <a href="http://www.w3.org/TR/xslt#section-Creating-Comments">section-Creating-Comments in XSLT Specification</a>
 * @xsl.usage advanced
 */
public class ElemComment extends ElemTemplateElement
{
    static final long serialVersionUID = -8813199122875770142L;

  /**
   * Get an int constant identifying the type of element.
   * @see org.apache.xalan.templates.Constants
   *
   * @return The token ID for this element
   */
  public int getXSLToken()
  {
    return Constants.ELEMNAME_COMMENT;
  }

  /**
   * Return the node name.
   *
   * @return This element's name
   */
  public String getNodeName()
  {
    return Constants.ELEMNAME_COMMENT_STRING;
  }

  /**
   * Execute the xsl:comment transformation 
   *
   *
   * @param transformer non-null reference to the the current transform-time state.
   *
   * @throws TransformerException
   */
  public void execute(
          TransformerImpl transformer)
            throws TransformerException
  {
    if (transformer.getDebug())
      transformer.getTraceManager().fireTraceEvent(this);
    try
    {
      // Note the content model is:
      // <!ENTITY % instructions "
      // %char-instructions;
      // | xsl:processing-instruction
      // | xsl:comment
      // | xsl:element
      // | xsl:attribute
      // ">
      String data = transformer.transformToString(this);

      transformer.getResultTreeHandler().comment(data);
    }
    catch(org.xml.sax.SAXException se)
    {
      throw new TransformerException(se);
    }
    finally
    {
      if (transformer.getDebug())
        transformer.getTraceManager().fireTraceEndEvent(this);
    }
  }

  /**
   * Add a child to the child list.
   *
   * @param newChild Child to add to this node's child list
   *
   * @return Child that was just added to child list
   *
   * @throws DOMException
   */
  public ElemTemplateElement appendChild(ElemTemplateElement newChild)
  {

    int type = ((ElemTemplateElement) newChild).getXSLToken();

    switch (type)
    {

    // char-instructions 
    case Constants.ELEMNAME_TEXTLITERALRESULT :
    case Constants.ELEMNAME_APPLY_TEMPLATES :
    case Constants.ELEMNAME_APPLY_IMPORTS :
    case Constants.ELEMNAME_CALLTEMPLATE :
    case Constants.ELEMNAME_FOREACH :
    case Constants.ELEMNAME_VALUEOF :
    case Constants.ELEMNAME_COPY_OF :
    case Constants.ELEMNAME_NUMBER :
    case Constants.ELEMNAME_CHOOSE :
    case Constants.ELEMNAME_IF :
    case Constants.ELEMNAME_TEXT :
    case Constants.ELEMNAME_COPY :
    case Constants.ELEMNAME_VARIABLE :
    case Constants.ELEMNAME_MESSAGE :

      // instructions 
      // case Constants.ELEMNAME_PI:
      // case Constants.ELEMNAME_COMMENT:
      // case Constants.ELEMNAME_ELEMENT:
      // case Constants.ELEMNAME_ATTRIBUTE:
      break;
    default :
      error(XSLTErrorResources.ER_CANNOT_ADD,
            new Object[]{ newChild.getNodeName(),
                          this.getNodeName() });  //"Can not add " +((ElemTemplateElement)newChild).m_elemName +

    //" to " + this.m_elemName);
    }

    return super.appendChild(newChild);
  }
}
