Home | History | Annotate | Download | only in axes 
      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: SelfIteratorNoPredicate.java 469263 2006-10-30 20:45:40Z minchau $
     20  */
     21 package org.apache.xpath.axes;
     22 
     23 import org.apache.xml.dtm.DTM;
     24 import org.apache.xpath.XPathContext;
     25 import org.apache.xpath.compiler.Compiler;
     26 
     27 /**
     28  * This class implements an optimized iterator for
     29  * "." patterns, that is, the self axes without any predicates.
     30  * @see org.apache.xpath.axes.LocPathIterator
     31  * @xsl.usage advanced
     32  */
     33 public class SelfIteratorNoPredicate extends LocPathIterator
     34 {
     35     static final long serialVersionUID = -4226887905279814201L;
     36 
     37   /**
     38    * Create a SelfIteratorNoPredicate object.
     39    *
     40    * @param compiler A reference to the Compiler that contains the op map.
     41    * @param opPos The position within the op map, which contains the
     42    * location path expression for this itterator.
     43    * @param analysis Analysis bits.
     44    *
     45    * @throws javax.xml.transform.TransformerException
     46    */
     47   SelfIteratorNoPredicate(Compiler compiler, int opPos, int analysis)
     48           throws javax.xml.transform.TransformerException
     49   {
     50     super(compiler, opPos, analysis, false);
     51   }
     52 
     53   /**
     54    * Create a SelfIteratorNoPredicate object.
     55    *
     56    * @throws javax.xml.transform.TransformerException
     57    */
     58   public SelfIteratorNoPredicate()
     59           throws javax.xml.transform.TransformerException
     60   {
     61     super(null);
     62   }
     63 
     64 
     65   /**
     66    *  Returns the next node in the set and advances the position of the
     67    * iterator in the set. After a NodeIterator is created, the first call
     68    * to nextNode() returns the first node in the set.
     69    *
     70    * @return  The next <code>Node</code> in the set being iterated over, or
     71    *   <code>null</code> if there are no more members in that set.
     72    */
     73   public int nextNode()
     74   {
     75     if (m_foundLast)
     76       return DTM.NULL;
     77 
     78     int next;
     79 
     80     m_lastFetched = next = (DTM.NULL == m_lastFetched)
     81                            ? m_context
     82                            : DTM.NULL;
     83 
     84     // m_lastFetched = next;
     85     if (DTM.NULL != next)
     86     {
     87       m_pos++;
     88 
     89       return next;
     90     }
     91     else
     92     {
     93       m_foundLast = true;
     94 
     95       return DTM.NULL;
     96     }
     97   }
     98 
     99   /**
    100    * Return the first node out of the nodeset, if this expression is
    101    * a nodeset expression.  This is the default implementation for
    102    * nodesets.  Derived classes should try and override this and return a
    103    * value without having to do a clone operation.
    104    * @param xctxt The XPath runtime context.
    105    * @return the first node out of the nodeset, or DTM.NULL.
    106    */
    107   public int asNode(XPathContext xctxt)
    108     throws javax.xml.transform.TransformerException
    109   {
    110     return xctxt.getCurrentNode();
    111   }
    112 
    113   /**
    114    * Get the index of the last node that can be itterated to.
    115    * This probably will need to be overridded by derived classes.
    116    *
    117    * @param xctxt XPath runtime context.
    118    *
    119    * @return the index of the last node that can be itterated to.
    120    */
    121   public int getLastPos(XPathContext xctxt)
    122   {
    123     return 1;
    124   }
    125 
    126 
    127 }
    128