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Java > Open Source Codes > org > apache > xpath > patterns > FunctionPattern


1 /*
2  * Copyright 1999-2004 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 /*
17  * $Id: FunctionPattern.java,v 1.13 2004/02/17 04:35:37 minchau Exp $
18  */
19 package org.apache.xpath.patterns;
20
21 import org.apache.xml.dtm.DTM;
22 import org.apache.xml.dtm.DTMIterator;
23 import org.apache.xpath.Expression;
24 import org.apache.xpath.ExpressionOwner;
25 import org.apache.xpath.XPathContext;
26 import org.apache.xpath.XPathVisitor;
27 import org.apache.xpath.objects.XNumber;
28 import org.apache.xpath.objects.XObject;
29
30 /**
31  * Match pattern step that contains a function.
32  * @xsl.usage advanced
33  */
34 public class FunctionPattern extends StepPattern
35 {
36
37   /**
38    * Construct a FunctionPattern from a
39    * {@link org.apache.xpath.functions.Function expression}.
40    *
41    *
42    * @param a should be a {@link org.apache.xpath.functions.Function expression}.
43    *
44    * NEEDSDOC @param expr
45    */
46   public FunctionPattern(Expression expr, int axis, int predaxis)
47   {
48
49     super(0, null, null, axis, predaxis);
50
51     m_functionExpr = expr;
52   }
53
54   /**
55    * Static calc of match score.
56    */
57   public final void calcScore()
58   {
59
60     m_score = SCORE_OTHER;
61
62     if (null == m_targetString)
63       calcTargetString();
64   }
65
66   /**
67    * Should be a {@link org.apache.xpath.functions.Function expression}.
68    * @serial
69    */
70   Expression m_functionExpr;
71   
72   /**
73    * This function is used to fixup variables from QNames to stack frame
74    * indexes at stylesheet build time.
75    * @param vars List of QNames that correspond to variables. This list
76    * should be searched backwards for the first qualified name that
77    * corresponds to the variable reference qname. The position of the
78    * QName in the vector from the start of the vector will be its position
79    * in the stack frame (but variables above the globalsTop value will need
80    * to be offset to the current stack frame).
81    */
82   public void fixupVariables(java.util.Vector JavaDoc vars, int globalsSize)
83   {
84     super.fixupVariables(vars, globalsSize);
85     m_functionExpr.fixupVariables(vars, globalsSize);
86   }
87
88   
89   /**
90    * Test a node to see if it matches the given node test.
91    *
92    * @param xctxt XPath runtime context.
93    *
94    * @return {@link org.apache.xpath.patterns.NodeTest#SCORE_NODETEST},
95    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NONE},
96    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NSWILD},
97    * {@link org.apache.xpath.patterns.NodeTest#SCORE_QNAME}, or
98    * {@link org.apache.xpath.patterns.NodeTest#SCORE_OTHER}.
99    *
100    * @throws javax.xml.transform.TransformerException
101    */
102   public XObject execute(XPathContext xctxt, int context)
103           throws javax.xml.transform.TransformerException JavaDoc
104   {
105
106     DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
107     XNumber score = SCORE_NONE;
108
109     if (null != nl)
110     {
111       int n;
112
113       while (DTM.NULL != (n = nl.nextNode()))
114       {
115         score = (n == context) ? SCORE_OTHER : SCORE_NONE;
116
117         if (score == SCORE_OTHER)
118         {
119           context = n;
120
121           break;
122         }
123       }
124
125       // nl.detach();
126 }
127     nl.detach();
128
129     return score;
130   }
131   
132   /**
133    * Test a node to see if it matches the given node test.
134    *
135    * @param xctxt XPath runtime context.
136    *
137    * @return {@link org.apache.xpath.patterns.NodeTest#SCORE_NODETEST},
138    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NONE},
139    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NSWILD},
140    * {@link org.apache.xpath.patterns.NodeTest#SCORE_QNAME}, or
141    * {@link org.apache.xpath.patterns.NodeTest#SCORE_OTHER}.
142    *
143    * @throws javax.xml.transform.TransformerException
144    */
145   public XObject execute(XPathContext xctxt, int context,
146                          DTM dtm, int expType)
147           throws javax.xml.transform.TransformerException JavaDoc
148   {
149
150     DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
151     XNumber score = SCORE_NONE;
152
153     if (null != nl)
154     {
155       int n;
156
157       while (DTM.NULL != (n = nl.nextNode()))
158       {
159         score = (n == context) ? SCORE_OTHER : SCORE_NONE;
160
161         if (score == SCORE_OTHER)
162         {
163           context = n;
164
165           break;
166         }
167       }
168
169       nl.detach();
170     }
171
172     return score;
173   }
174   
175   /**
176    * Test a node to see if it matches the given node test.
177    *
178    * @param xctxt XPath runtime context.
179    *
180    * @return {@link org.apache.xpath.patterns.NodeTest#SCORE_NODETEST},
181    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NONE},
182    * {@link org.apache.xpath.patterns.NodeTest#SCORE_NSWILD},
183    * {@link org.apache.xpath.patterns.NodeTest#SCORE_QNAME}, or
184    * {@link org.apache.xpath.patterns.NodeTest#SCORE_OTHER}.
185    *
186    * @throws javax.xml.transform.TransformerException
187    */
188   public XObject execute(XPathContext xctxt)
189           throws javax.xml.transform.TransformerException JavaDoc
190   {
191
192     int context = xctxt.getCurrentNode();
193     DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
194     XNumber score = SCORE_NONE;
195
196     if (null != nl)
197     {
198       int n;
199
200       while (DTM.NULL != (n = nl.nextNode()))
201       {
202         score = (n == context) ? SCORE_OTHER : SCORE_NONE;
203
204         if (score == SCORE_OTHER)
205         {
206           context = n;
207
208           break;
209         }
210       }
211
212       nl.detach();
213     }
214
215     return score;
216   }
217   
218   class FunctionOwner implements ExpressionOwner
219   {
220     /**
221      * @see ExpressionOwner#getExpression()
222      */
223     public Expression getExpression()
224     {
225       return m_functionExpr;
226     }
227
228
229     /**
230      * @see ExpressionOwner#setExpression(Expression)
231      */
232     public void setExpression(Expression exp)
233     {
234         exp.exprSetParent(FunctionPattern.this);
235         m_functionExpr = exp;
236     }
237   }
238   
239   /**
240    * Call the visitor for the function.
241    */
242   protected void callSubtreeVisitors(XPathVisitor visitor)
243   {
244     m_functionExpr.callVisitors(new FunctionOwner(), visitor);
245     super.callSubtreeVisitors(visitor);
246   }
247
248 }
249
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