1/*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5/*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements.  See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License.  You may obtain a copy of the License at
12 *
13 *      http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22package com.sun.org.apache.xpath.internal.axes;
23
24import com.sun.org.apache.xml.internal.dtm.DTM;
25import com.sun.org.apache.xml.internal.dtm.DTMFilter;
26import com.sun.org.apache.xpath.internal.Expression;
27import com.sun.org.apache.xpath.internal.compiler.Compiler;
28import com.sun.org.apache.xpath.internal.compiler.OpMap;
29
30/**
31 * This class implements a general iterator for
32 * those LocationSteps with only one step, and perhaps a predicate,
33 * that only go forward (i.e. it can not be used with ancestors,
34 * preceding, etc.)
35 * @see com.sun.org.apache.xpath.internal.axes#ChildTestIterator
36 * @xsl.usage advanced
37 */
38public class OneStepIteratorForward extends ChildTestIterator
39{
40    static final long serialVersionUID = -1576936606178190566L;
41  /** The traversal axis from where the nodes will be filtered. */
42  protected int m_axis = -1;
43
44  /**
45   * Create a OneStepIterator object.
46   *
47   * @param compiler A reference to the Compiler that contains the op map.
48   * @param opPos The position within the op map, which contains the
49   * location path expression for this itterator.
50   *
51   * @throws javax.xml.transform.TransformerException
52   */
53  OneStepIteratorForward(Compiler compiler, int opPos, int analysis)
54          throws javax.xml.transform.TransformerException
55  {
56    super(compiler, opPos, analysis);
57    int firstStepPos = OpMap.getFirstChildPos(opPos);
58
59    m_axis = WalkerFactory.getAxisFromStep(compiler, firstStepPos);
60
61  }
62
63  /**
64   * Create a OneStepIterator object that will just traverse the self axes.
65   *
66   * @param axis One of the com.sun.org.apache.xml.internal.dtm.Axis integers.
67   *
68   * @throws javax.xml.transform.TransformerException
69   */
70  public OneStepIteratorForward(int axis)
71  {
72    super(null);
73
74    m_axis = axis;
75    int whatToShow = DTMFilter.SHOW_ALL;
76    initNodeTest(whatToShow);
77  }
78
79
80
81
82  /**
83   * Initialize the context values for this expression
84   * after it is cloned.
85   *
86   * @param context The XPath runtime context for this
87   * transformation.
88   */
89  public void setRoot(int context, Object environment)
90  {
91    super.setRoot(context, environment);
92    m_traverser = m_cdtm.getAxisTraverser(m_axis);
93
94  }
95
96//  /**
97//   * Return the first node out of the nodeset, if this expression is
98//   * a nodeset expression.  This is the default implementation for
99//   * nodesets.
100//   * <p>WARNING: Do not mutate this class from this function!</p>
101//   * @param xctxt The XPath runtime context.
102//   * @return the first node out of the nodeset, or DTM.NULL.
103//   */
104//  public int asNode(XPathContext xctxt)
105//    throws javax.xml.transform.TransformerException
106//  {
107//    if(getPredicateCount() > 0)
108//      return super.asNode(xctxt);
109//
110//    int current = xctxt.getCurrentNode();
111//
112//    DTM dtm = xctxt.getDTM(current);
113//    DTMAxisTraverser traverser = dtm.getAxisTraverser(m_axis);
114//
115//    String localName = getLocalName();
116//    String namespace = getNamespace();
117//    int what = m_whatToShow;
118//
119//    // System.out.println("what: ");
120//    // NodeTest.debugWhatToShow(what);
121//    if(DTMFilter.SHOW_ALL == what
122//       || ((DTMFilter.SHOW_ELEMENT & what) == 0)
123//       || localName == NodeTest.WILD
124//       || namespace == NodeTest.WILD)
125//    {
126//      return traverser.first(current);
127//    }
128//    else
129//    {
130//      int type = getNodeTypeTest(what);
131//      int extendedType = dtm.getExpandedTypeID(namespace, localName, type);
132//      return traverser.first(current, extendedType);
133//    }
134//  }
135
136  /**
137   * Get the next node via getFirstAttribute && getNextAttribute.
138   */
139  protected int getNextNode()
140  {
141    m_lastFetched = (DTM.NULL == m_lastFetched)
142                     ? m_traverser.first(m_context)
143                     : m_traverser.next(m_context, m_lastFetched);
144    return m_lastFetched;
145  }
146
147  /**
148   * Returns the axis being iterated, if it is known.
149   *
150   * @return Axis.CHILD, etc., or -1 if the axis is not known or is of multiple
151   * types.
152   */
153  public int getAxis()
154  {
155    return m_axis;
156  }
157
158  /**
159   * @see Expression#deepEquals(Expression)
160   */
161  public boolean deepEquals(Expression expr)
162  {
163        if(!super.deepEquals(expr))
164                return false;
165
166        if(m_axis != ((OneStepIteratorForward)expr).m_axis)
167                return false;
168
169        return true;
170  }
171
172
173}
174