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
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 org.apache.bcel.Constants;
58 import java.io.*;
59
60 /***
61 * This class represents a local variable within a method. It contains its
62 * scope, name, signature and index on the method's frame.
63 *
64 * @version $Id: LocalVariable.java,v 1.3 2002/07/11 19:39:04 mdahm Exp $
65 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
66 * @see LocalVariableTable
67 */
68 public final class LocalVariable
69 implements Constants, Cloneable, Node, Serializable
70 {
71 private int start_pc; // Range in which the variable is valid
72 private int length;
73 private int name_index; // Index in constant pool of variable name
74 private int signature_index; // Index of variable signature
75 private int index; /* Variable is `index'th local variable on
76 * this method's frame.
77 */
78
79 private ConstantPool constant_pool;
80
81 /***
82 * Initialize from another object. Note that both objects use the same
83 * references (shallow copy). Use copy() for a physical copy.
84 */
85 public LocalVariable(LocalVariable c) {
86 this(c.getStartPC(), c.getLength(), c.getNameIndex(),
87 c.getSignatureIndex(), c.getIndex(), c.getConstantPool());
88 }
89
90 /***
91 * Construct object from file stream.
92 * @param file Input stream
93 * @throws IOException
94 */
95 LocalVariable(DataInputStream file, ConstantPool constant_pool)
96 throws IOException
97 {
98 this(file.readUnsignedShort(), file.readUnsignedShort(),
99 file.readUnsignedShort(), file.readUnsignedShort(),
100 file.readUnsignedShort(), constant_pool);
101 }
102
103 /***
104 * @param start_pc Range in which the variable
105 * @param length ... is valid
106 * @param name_index Index in constant pool of variable name
107 * @param signature_index Index of variable's signature
108 * @param index Variable is `index'th local variable on the method's frame
109 * @param constant_pool Array of constants
110 */
111 public LocalVariable(int start_pc, int length, int name_index,
112 int signature_index, int index,
113 ConstantPool constant_pool)
114 {
115 this.start_pc = start_pc;
116 this.length = length;
117 this.name_index = name_index;
118 this.signature_index = signature_index;
119 this.index = index;
120 this.constant_pool = constant_pool;
121 }
122
123 /***
124 * Called by objects that are traversing the nodes of the tree implicitely
125 * defined by the contents of a Java class. I.e., the hierarchy of methods,
126 * fields, attributes, etc. spawns a tree of objects.
127 *
128 * @param v Visitor object
129 */
130 public void accept(Visitor v) {
131 v.visitLocalVariable(this);
132 }
133
134 /***
135 * Dump local variable to file stream in binary format.
136 *
137 * @param file Output file stream
138 * @throws IOException
139 */
140 public final void dump(DataOutputStream file) throws IOException
141 {
142 file.writeShort(start_pc);
143 file.writeShort(length);
144 file.writeShort(name_index);
145 file.writeShort(signature_index);
146 file.writeShort(index);
147 }
148
149 /***
150 * @return Constant pool used by this object.
151 */
152 public final ConstantPool getConstantPool() { return constant_pool; }
153
154 /***
155 * @return Variable is valid within getStartPC() .. getStartPC()+getLength()
156 */
157 public final int getLength() { return length; }
158
159 /***
160 * @return Variable name.
161 */
162 public final String getName() {
163 ConstantUtf8 c;
164
165 c = (ConstantUtf8)constant_pool.getConstant(name_index, CONSTANT_Utf8);
166 return c.getBytes();
167 }
168
169 /***
170 * @return Index in constant pool of variable name.
171 */
172 public final int getNameIndex() { return name_index; }
173
174 /***
175 * @return Signature.
176 */
177 public final String getSignature() {
178 ConstantUtf8 c;
179 c = (ConstantUtf8)constant_pool.getConstant(signature_index,
180 CONSTANT_Utf8);
181 return c.getBytes();
182 }
183
184 /***
185 * @return Index in constant pool of variable signature.
186 */
187 public final int getSignatureIndex() { return signature_index; }
188
189 /***
190 * @return index of register where variable is stored
191 */
192 public final int getIndex() { return index; }
193
194 /***
195 * @return Start of range where he variable is valid
196 */
197 public final int getStartPC() { return start_pc; }
198
199 /***
200 * @param constant_pool Constant pool to be used for this object.
201 */
202 public final void setConstantPool(ConstantPool constant_pool) {
203 this.constant_pool = constant_pool;
204 }
205
206 /***
207 * @param length.
208 */
209 public final void setLength(int length) {
210 this.length = length;
211 }
212
213 /***
214 * @param name_index.
215 */
216 public final void setNameIndex(int name_index) {
217 this.name_index = name_index;
218 }
219
220 /***
221 * @param signature_index.
222 */
223 public final void setSignatureIndex(int signature_index) {
224 this.signature_index = signature_index;
225 }
226
227 /***
228 * @param index.
229 */
230 public final void setIndex(int index) { this.index = index; }
231
232 /***
233 * @param start_pc Specify range where the local variable is valid.
234 */
235 public final void setStartPC(int start_pc) {
236 this.start_pc = start_pc;
237 }
238
239 /***
240 * @return string representation.
241 */
242 public final String toString() {
243 String name = getName(), signature = Utility.signatureToString(getSignature());
244
245 return "LocalVariable(start_pc = " + start_pc + ", length = " + length +
246 ", index = " + index + ":" + signature + " " + name + ")";
247 }
248
249 /***
250 * @return deep copy of this object
251 */
252 public LocalVariable copy() {
253 try {
254 return (LocalVariable)clone();
255 } catch(CloneNotSupportedException e) {}
256
257 return null;
258 }
259 }
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