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Java > Open Source Codes > org > apache > xpath > operations > Equals


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: Equals.java,v 1.9 2004/02/17 04:35:12 minchau Exp $
18  */
19 package org.apache.xpath.operations;
20
21 import org.apache.xpath.XPathContext;
22 import org.apache.xpath.objects.XBoolean;
23 import org.apache.xpath.objects.XObject;
24
25 /**
26  * The '=' operation expression executer.
27  */
28 public class Equals extends Operation
29 {
30
31   /**
32    * Apply the operation to two operands, and return the result.
33    *
34    *
35    * @param left non-null reference to the evaluated left operand.
36    * @param right non-null reference to the evaluated right operand.
37    *
38    * @return non-null reference to the XObject that represents the result of the operation.
39    *
40    * @throws javax.xml.transform.TransformerException
41    */
42   public XObject operate(XObject left, XObject right)
43           throws javax.xml.transform.TransformerException JavaDoc
44   {
45     return left.equals(right) ? XBoolean.S_TRUE : XBoolean.S_FALSE;
46   }
47   
48   /**
49    * Execute a binary operation by calling execute on each of the operands,
50    * and then calling the operate method on the derived class.
51    *
52    *
53    * @param xctxt The runtime execution context.
54    *
55    * @return The XObject result of the operation.
56    *
57    * @throws javax.xml.transform.TransformerException
58    */
59   public boolean bool(XPathContext xctxt)
60           throws javax.xml.transform.TransformerException JavaDoc
61   {
62     XObject left = m_left.execute(xctxt, true);
63     XObject right = m_right.execute(xctxt, true);
64
65     boolean result = left.equals(right) ? true : false;
66     left.detach();
67     right.detach();
68     return result;
69   }
70
71 }
72
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