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      1 /*
      2  * Licensed to the Apache Software Foundation (ASF) under one
      3  * or more contributor license agreements. See the NOTICE file
      4  * distributed with this work for additional information
      5  * regarding copyright ownership. The ASF licenses this file
      6  * to you under the Apache License, Version 2.0 (the  "License");
      7  * you may not use this file except in compliance with the License.
      8  * You may obtain a copy of the License at
      9  *
     10  *     http://www.apache.org/licenses/LICENSE-2.0
     11  *
     12  * Unless required by applicable law or agreed to in writing, software
     13  * distributed under the License is distributed on an "AS IS" BASIS,
     14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     15  * See the License for the specific language governing permissions and
     16  * limitations under the License.
     17  */
     18 /*
     19  * $Id: FuncLast.java 468655 2006-10-28 07:12:06Z minchau $
     20  */
     21 package org.apache.xpath.functions;
     22 
     23 import org.apache.xml.dtm.DTMIterator;
     24 import org.apache.xpath.XPathContext;
     25 import org.apache.xpath.axes.SubContextList;
     26 import org.apache.xpath.compiler.Compiler;
     27 import org.apache.xpath.objects.XNumber;
     28 import org.apache.xpath.objects.XObject;
     29 
     30 
     31 /**
     32  * Execute the Last() function.
     33  * @xsl.usage advanced
     34  */
     35 public class FuncLast extends Function
     36 {
     37     static final long serialVersionUID = 9205812403085432943L;
     38 
     39   private boolean m_isTopLevel;
     40 
     41   /**
     42    * Figure out if we're executing a toplevel expression.
     43    * If so, we can't be inside of a predicate.
     44    */
     45   public void postCompileStep(Compiler compiler)
     46   {
     47     m_isTopLevel = compiler.getLocationPathDepth() == -1;
     48   }
     49 
     50   /**
     51    * Get the position in the current context node list.
     52    *
     53    * @param xctxt non-null reference to XPath runtime context.
     54    *
     55    * @return The number of nodes in the list.
     56    *
     57    * @throws javax.xml.transform.TransformerException
     58    */
     59   public int getCountOfContextNodeList(XPathContext xctxt)
     60           throws javax.xml.transform.TransformerException
     61   {
     62 
     63     // assert(null != m_contextNodeList, "m_contextNodeList must be non-null");
     64     // If we're in a predicate, then this will return non-null.
     65     SubContextList iter = m_isTopLevel ? null : xctxt.getSubContextList();
     66 
     67     // System.out.println("iter: "+iter);
     68     if (null != iter)
     69       return iter.getLastPos(xctxt);
     70 
     71     DTMIterator cnl = xctxt.getContextNodeList();
     72     int count;
     73     if(null != cnl)
     74     {
     75       count = cnl.getLength();
     76       // System.out.println("count: "+count);
     77     }
     78     else
     79       count = 0;
     80     return count;
     81   }
     82 
     83   /**
     84    * Execute the function.  The function must return
     85    * a valid object.
     86    * @param xctxt The current execution context.
     87    * @return A valid XObject.
     88    *
     89    * @throws javax.xml.transform.TransformerException
     90    */
     91   public XObject execute(XPathContext xctxt) throws javax.xml.transform.TransformerException
     92   {
     93     XNumber xnum = new XNumber((double) getCountOfContextNodeList(xctxt));
     94     // System.out.println("last: "+xnum.num());
     95     return xnum;
     96   }
     97 
     98   /**
     99    * No arguments to process, so this does nothing.
    100    */
    101   public void fixupVariables(java.util.Vector vars, int globalsSize)
    102   {
    103     // no-op
    104   }
    105 
    106 }
    107