1   package org.apache.bcel.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
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39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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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,
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  org.apache.bcel.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 1.2 2002/03/11 16:16:35 mdahm 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    * @throws 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    * @throws 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 toString() {
169     StringBuffer buf = new StringBuffer("");
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 }
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