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Java > Open Source Codes > com > sun > org > apache > bcel > internal > verifier > structurals > Frame


1 package com.sun.org.apache.bcel.internal.verifier.structurals;
2
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2001 The Apache Software Foundation. All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  * notice, this list of conditions and the following disclaimer in
18  * the documentation and/or other materials provided with the
19  * distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  * if any, must include the following acknowledgment:
23  * "This product includes software developed by the
24  * Apache Software Foundation (http://www.apache.org/)."
25  * Alternately, this acknowledgment may appear in the software itself,
26  * if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation" and
29  * "Apache BCEL" must not be used to endorse or promote products
30  * derived from this software without prior written permission. For
31  * written permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache",
34  * "Apache BCEL", nor may "Apache" appear in their name, without
35  * prior written permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
44  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation. For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  */
56
57 import com.sun.org.apache.bcel.internal.generic.*;
58 import com.sun.org.apache.bcel.internal.verifier.exc.*;
59 import java.util.ArrayList JavaDoc;
60
61 /**
62  * This class represents a JVM execution frame; that means,
63  * a local variable array and an operand stack.
64  *
65  * @version $Id: Frame.java,v 1.1.1.1 2001/10/29 20:00:39 jvanzyl Exp $
66  * @author <A HREF="http://www.inf.fu-berlin.de/~ehaase"/>Enver Haase</A>
67  */
68  
69 public class Frame{
70
71     /**
72      * For instance initialization methods, it is important to remember
73      * which instance it is that is not initialized yet. It will be
74      * initialized invoking another constructor later.
75      * NULL means the instance already *is* initialized.
76      */
77     protected static UninitializedObjectType _this;
78
79     /**
80      *
81      */
82     private LocalVariables locals;
83
84     /**
85      *
86      */
87     private OperandStack stack;
88
89     /**
90      *
91      */
92     public Frame(int maxLocals, int maxStack){
93         locals = new LocalVariables(maxLocals);
94         stack = new OperandStack(maxStack);
95     }
96
97     /**
98      *
99      */
100     public Frame(LocalVariables locals, OperandStack stack){
101         this.locals = locals;
102         this.stack = stack;
103     }
104
105     /**
106      *
107      */
108     protected Object JavaDoc clone(){
109         Frame f = new Frame(locals.getClone(), stack.getClone());
110         return f;
111     }
112
113     /**
114      *
115      */
116     public Frame getClone(){
117         return (Frame) clone();
118     }
119
120     /**
121      *
122      */
123     public LocalVariables getLocals(){
124         return locals;
125     }
126
127     /**
128      *
129      */
130     public OperandStack getStack(){
131         return stack;
132     }
133
134     /**
135      *
136      */
137     public boolean equals(Object JavaDoc o){
138         if (!(o instanceof Frame)) return false; // implies "null" is non-equal.
139 Frame f = (Frame) o;
140         return this.stack.equals(f.stack) && this.locals.equals(f.locals);
141     }
142
143     /**
144      * Returns a String representation of the Frame instance.
145      */
146     public String JavaDoc toString(){
147         String JavaDoc s="Local Variables:\n";
148         s += locals;
149         s += "OperandStack:\n";
150         s += stack;
151         return s;
152     }
153 }
154
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