code: /*
   * 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.xpath.functions;
  
  import org.apache.xml.dtm.DTMIterator;
  import org.apache.xpath.XPathContext;
  import org.apache.xpath.axes.SubContextList;
  import org.apache.xpath.compiler.Compiler;
  import org.apache.xpath.objects.XNumber;
  import org.apache.xpath.objects.XObject;
  
  
  /**
   * Execute the Last() function.
   * @xsl.usage advanced
   */
  public class FuncLast extends Function
  {
      static final long serialVersionUID = 9205812403085432943L;
    
    private boolean m_isTopLevel;
    
    /**
     * Figure out if we're executing a toplevel expression.
     * If so, we can't be inside of a predicate. 
     */
    public void postCompileStep(Compiler compiler)
    {
      m_isTopLevel = compiler.getLocationPathDepth() == -1;
    }
  
    /**
     * Get the position in the current context node list.
     *
     * @param xctxt non-null reference to XPath runtime context.
     *
     * @return The number of nodes in the list.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public int getCountOfContextNodeList(XPathContext xctxt)
            throws javax.xml.transform.TransformerException
    {
  
      // assert(null != m_contextNodeList, "m_contextNodeList must be non-null");
      // If we're in a predicate, then this will return non-null.
      SubContextList iter = m_isTopLevel ? null : xctxt.getSubContextList();
  
      // System.out.println("iter: "+iter);
      if (null != iter)
        return iter.getLastPos(xctxt);
  
      DTMIterator cnl = xctxt.getContextNodeList();
      int count;
      if(null != cnl)
      {
        count = cnl.getLength();
        // System.out.println("count: "+count); 
      }
      else
        count = 0;   
      return count;
    }
  
    /**
     * 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
    {
      XNumber xnum = new XNumber((double) getCountOfContextNodeList(xctxt));
      // System.out.println("last: "+xnum.num());
      return xnum;
    }
    
    /**
     * No arguments to process, so this does nothing.
     */
    public void fixupVariables(java.util.Vector vars, int globalsSize)
    {
      // no-op
    }
  
  }
  