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Java > Open Source Codes > com > sun > org > apache > bcel > internal > classfile > LocalVariableTable


1 package com.sun.org.apache.bcel.internal.classfile;
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
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41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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48  * SUCH DAMAGE.
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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.Constants;
58 import java.io.*;
59
60 /**
61  * This class represents colection of local variables in a
62  * method. This attribute is contained in the <em>Code</em> attribute.
63  *
64  * @version $Id: LocalVariableTable.java,v 1.1.1.1 2001/10/29 20:00:02 jvanzyl Exp $
65  * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
66  * @see Code
67  * @see LocalVariable
68  */
69 public class LocalVariableTable extends Attribute {
70   private int local_variable_table_length; // Table of local
71 private LocalVariable[] local_variable_table; // variables
72
73   /**
74    * Initialize from another object. Note that both objects use the same
75    * references (shallow copy). Use copy() for a physical copy.
76    */
77   public LocalVariableTable(LocalVariableTable c) {
78     this(c.getNameIndex(), c.getLength(), c.getLocalVariableTable(),
79      c.getConstantPool());
80   }
81
82   /**
83    * @param name_index Index in constant pool to `LocalVariableTable'
84    * @param length Content length in bytes
85    * @param local_variable_table Table of local variables
86    * @param constant_pool Array of constants
87    */
88   public LocalVariableTable(int name_index, int length,
89                 LocalVariable[] local_variable_table,
90                 ConstantPool constant_pool)
91   {
92     super(Constants.ATTR_LOCAL_VARIABLE_TABLE, name_index, length, constant_pool);
93     setLocalVariableTable(local_variable_table);
94   }
95
96   /**
97    * Construct object from file stream.
98    * @param name_index Index in constant pool
99    * @param length Content length in bytes
100    * @param file Input stream
101    * @param constant_pool Array of constants
102    * @throw IOException
103    */
104   LocalVariableTable(int name_index, int length, DataInputStream file,
105              ConstantPool constant_pool) throws IOException
106   {
107     this(name_index, length, (LocalVariable[])null, constant_pool);
108
109     local_variable_table_length = (file.readUnsignedShort());
110     local_variable_table = new LocalVariable[local_variable_table_length];
111
112     for(int i=0; i < local_variable_table_length; i++)
113       local_variable_table[i] = new LocalVariable(file, constant_pool);
114   }
115
116   /**
117    * Called by objects that are traversing the nodes of the tree implicitely
118    * defined by the contents of a Java class. I.e., the hierarchy of methods,
119    * fields, attributes, etc. spawns a tree of objects.
120    *
121    * @param v Visitor object
122    */
123   public void accept(Visitor v) {
124     v.visitLocalVariableTable(this);
125   }
126
127   /**
128    * Dump local variable table attribute to file stream in binary format.
129    *
130    * @param file Output file stream
131    * @throw IOException
132    */
133   public final void dump(DataOutputStream file) throws IOException
134   {
135     super.dump(file);
136     file.writeShort(local_variable_table_length);
137     for(int i=0; i < local_variable_table_length; i++)
138       local_variable_table[i].dump(file);
139   }
140
141   /**
142    * @return Array of local variables of method.
143    */
144   public final LocalVariable[] getLocalVariableTable() {
145     return local_variable_table;
146   }
147
148   /** @return first matching variable using index
149    */
150   public final LocalVariable getLocalVariable(int index) {
151     for(int i=0; i < local_variable_table_length; i++)
152       if(local_variable_table[i].getIndex() == index)
153     return local_variable_table[i];
154
155     return null;
156   }
157
158   public final void setLocalVariableTable(LocalVariable[] local_variable_table)
159   {
160     this.local_variable_table = local_variable_table;
161     local_variable_table_length = (local_variable_table == null)? 0 :
162       local_variable_table.length;
163   }
164
165   /**
166    * @return String representation.
167    */
168   public final String JavaDoc toString() {
169     StringBuffer JavaDoc buf = new StringBuffer JavaDoc("");
170
171     for(int i=0; i < local_variable_table_length; i++) {
172       buf.append(local_variable_table[i].toString());
173
174       if(i < local_variable_table_length - 1)
175     buf.append('\n');
176     }
177
178     return buf.toString();
179   }
180
181   /**
182    * @return deep copy of this attribute
183    */
184   public Attribute copy(ConstantPool constant_pool) {
185     LocalVariableTable c = (LocalVariableTable)clone();
186
187     c.local_variable_table = new LocalVariable[local_variable_table_length];
188     for(int i=0; i < local_variable_table_length; i++)
189       c.local_variable_table[i] = local_variable_table[i].copy();
190
191     c.constant_pool = constant_pool;
192     return c;
193   }
194
195   public final int getTableLength() { return local_variable_table_length; }
196 }
197
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