/*
 * Copyright 1999-2004 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.
 */
/*
 * $Id: ElemApplyImport.java,v 1.14 2004/02/16 20:32:33 minchau Exp $
 */
package org.apache.xalan.templates;

import javax.xml.transform.TransformerException;

import org.apache.xalan.res.XSLTErrorResources;
import org.apache.xalan.transformer.TransformerImpl;
import org.apache.xml.dtm.DTM;

/**
 * Implement xsl:apply-imports.
 * <pre>
 * <!ELEMENT xsl:apply-imports EMPTY>
 * </pre>
 * @see <a href="http://www.w3.org/TR/xslt#apply-imports">apply-imports in XSLT Specification</a>
 * @xsl.usage advanced
 */
public class ElemApplyImport extends ElemTemplateElement
{

  /**
   * Get an int constant identifying the type of element.
   * @see org.apache.xalan.templates.Constants
   *
   * @return Token ID for xsl:apply-imports element types
   */
  public int getXSLToken()
  {
    return Constants.ELEMNAME_APPLY_IMPORTS;
  }

  /**
   * Return the node name.
   *
   * @return Element name
   */
  public String getNodeName()
  {
    return Constants.ELEMNAME_APPLY_IMPORTS_STRING;
  }

  /**
   * Execute the xsl:apply-imports transformation.
   *
   * @param transformer non-null reference to the the current transform-time state.
   * @param sourceNode non-null reference to the <a href="http://www.w3.org/TR/xslt#dt-current-node">current source node</a>.
   * @param mode reference, which may be null, to the <a href="http://www.w3.org/TR/xslt#modes">current mode</a>.
   *
   * @throws TransformerException
   */
  public void execute(
          TransformerImpl transformer)
            throws TransformerException
  {

    if (transformer.currentTemplateRuleIsNull())
    {
      transformer.getMsgMgr().error(this,
        XSLTErrorResources.ER_NO_APPLY_IMPORT_IN_FOR_EACH);  //"xsl:apply-imports not allowed in a xsl:for-each");
    }

    if (TransformerImpl.S_DEBUG)
      transformer.getTraceManager().fireTraceEvent(this);

    int sourceNode = transformer.getXPathContext().getCurrentNode();
    if (DTM.NULL != sourceNode)
    {

      // This will have to change to current template, (which will have 
      // to be the top of a current template stack).
      transformer.applyTemplateToNode(this, null, sourceNode);
    }
    else  // if(null == sourceNode)
    {
      transformer.getMsgMgr().error(this,
        XSLTErrorResources.ER_NULL_SOURCENODE_APPLYIMPORTS);  //"sourceNode is null in xsl:apply-imports!");
    }
    if (TransformerImpl.S_DEBUG)
      transformer.getTraceManager().fireTraceEndEvent(this);
  }

  /**
   * Add a child to the child list.
   * <!ELEMENT xsl:apply-imports EMPTY>
   *
   * @param newChild New element to append to this element's children list
   *
   * @return null, xsl:apply-Imports cannot have children 
   */
  public ElemTemplateElement appendChild(ElemTemplateElement newChild)
  {

    error(XSLTErrorResources.ER_CANNOT_ADD,
          new Object[]{ newChild.getNodeName(),
                        this.getNodeName() });  //"Can not add " +((ElemTemplateElement)newChild).m_elemName +

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