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Java > Open Source Codes > org > jibx > binding > classes > BranchTarget


1 /*
2 Copyright (c) 2004, Dennis M. Sosnoski
3 All rights reserved.
4
5 Redistribution and use in source and binary forms, with or without modification,
6 are permitted provided that the following conditions are met:
7
8  * Redistributions of source code must retain the above copyright notice, this
9    list of conditions and the following disclaimer.
10  * Redistributions in binary form must reproduce the above copyright notice,
11    this list of conditions and the following disclaimer in the documentation
12    and/or other materials provided with the distribution.
13  * Neither the name of JiBX nor the names of its contributors may be used
14    to endorse or promote products derived from this software without specific
15    prior written permission.
16
17 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
18 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
21 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
24 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 package org.jibx.binding.classes;
30
31 import org.apache.bcel.generic.InstructionHandle;
32
33 /**
34  * Wrapper for branch target information. This preserves a snapshot of the stack
35  * state for the branch target, allowing it to be matched against the stack
36  * state for the branch source.
37  *
38  * @author Dennis M. Sosnoski
39  * @version 1.0
40  */
41
42 public class BranchTarget
43 {
44     /** Actual wrapped instruction handle. */
45     private final InstructionHandle m_targetHandle;
46     
47     /** Stack state for branch target. */
48     private final String JavaDoc[] m_stackTypes;
49     
50     /**
51      * Constructor.
52      *
53      * @param hand instruction handle
54      * @param types array of types of values on stack
55      */
56
57     /*package*/ BranchTarget(InstructionHandle hand, String JavaDoc[] types) {
58         m_targetHandle = hand;
59         m_stackTypes = types;
60     }
61
62     /**
63      * Get actual target instruction.
64      *
65      * @return handle for target instruction
66      */
67
68     /*package*/ InstructionHandle getInstruction() {
69         return m_targetHandle;
70     }
71
72     /**
73      * Get stack state information.
74      *
75      * @return array of type names on stack
76      */
77
78     /*package*/ String JavaDoc[] getStack() {
79         return m_stackTypes;
80     }
81     
82     /**
83      * Matches the branch target stack state against the supplied stack state.
84      *
85      * @param types array of types of values on stack
86      * @return <code>true</code> if stack states match, <code>false</code> if
87      * not
88      */
89      
90     /*package*/ boolean matchStacks(String JavaDoc[] types) {
91         
92         // match stack states
93 if (types.length == m_stackTypes.length) {
94             for (int i = 0; i < types.length; i++) {
95                 if (!types[i].equals(m_stackTypes[i])) {
96                     return false;
97                 }
98             }
99             return true;
100         } else {
101             return false;
102         }
103     }
104 }
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