/*
 * 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: FuncGenerateId.java,v 1.11 2004/08/17 19:25:36 jycli Exp $
 */
package org.apache.xpath.functions;

import org.apache.xml.dtm.DTM;
import org.apache.xpath.XPathContext;
import org.apache.xpath.objects.XObject;
import org.apache.xpath.objects.XString;

/**
 * Execute the GenerateId() function.
 * @xsl.usage advanced
 */
public class FuncGenerateId extends FunctionDef1Arg
{
    static final long serialVersionUID = 973544842091724273L;

  /**
   * Execute the function.  The function must return
   * a valid object.
   * @param xctxt The current execution context.
   * @return A valid XObject.
   *
   * @throws javax.xml.transform.TransformerException
   */
  public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
  {

    int which = getArg0AsNode(xctxt);

    if (DTM.NULL != which)
    {
      // Note that this is a different value than in previous releases
      // of Xalan. It's sensitive to the exact encoding of the node
      // handle anyway, so fighting to maintain backward compatability
      // really didn't make sense; it may change again as we continue
      // to experiment with balancing document and node numbers within
      // that value.
      return new XString("N" + Integer.toHexString(which).toUpperCase());
    }
    else
      return XString.EMPTYSTRING;
  }
}