1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 package org.apache.bcel.classfile;
18
19 import java.io.DataInputStream;
20 import java.io.DataOutputStream;
21 import java.io.IOException;
22 import org.apache.bcel.Constants;
23
24 /***
25 * This class represents the table of exceptions that are thrown by a
26 * method. This attribute may be used once per method. The name of
27 * this class is <em>ExceptionTable</em> for historical reasons; The
28 * Java Virtual Machine Specification, Second Edition defines this
29 * attribute using the name <em>Exceptions</em> (which is inconsistent
30 * with the other classes).
31 *
32 * @version $Id: ExceptionTable.java 386056 2006-03-15 11:31:56Z tcurdt $
33 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
34 * @see Code
35 */
36 public final class ExceptionTable extends Attribute {
37
38 private int number_of_exceptions;
39 private int[] exception_index_table;
40
41
42 /***
43 * Initialize from another object. Note that both objects use the same
44 * references (shallow copy). Use copy() for a physical copy.
45 */
46 public ExceptionTable(ExceptionTable c) {
47 this(c.getNameIndex(), c.getLength(), c.getExceptionIndexTable(), c.getConstantPool());
48 }
49
50
51 /***
52 * @param name_index Index in constant pool
53 * @param length Content length in bytes
54 * @param exception_index_table Table of indices in constant pool
55 * @param constant_pool Array of constants
56 */
57 public ExceptionTable(int name_index, int length, int[] exception_index_table,
58 ConstantPool constant_pool) {
59 super(Constants.ATTR_EXCEPTIONS, name_index, length, constant_pool);
60 setExceptionIndexTable(exception_index_table);
61 }
62
63
64 /***
65 * Construct object from file stream.
66 * @param name_index Index in constant pool
67 * @param length Content length in bytes
68 * @param file Input stream
69 * @param constant_pool Array of constants
70 * @throws IOException
71 */
72 ExceptionTable(int name_index, int length, DataInputStream file, ConstantPool constant_pool)
73 throws IOException {
74 this(name_index, length, (int[]) null, constant_pool);
75 number_of_exceptions = file.readUnsignedShort();
76 exception_index_table = new int[number_of_exceptions];
77 for (int i = 0; i < number_of_exceptions; i++) {
78 exception_index_table[i] = file.readUnsignedShort();
79 }
80 }
81
82
83 /***
84 * Called by objects that are traversing the nodes of the tree implicitely
85 * defined by the contents of a Java class. I.e., the hierarchy of methods,
86 * fields, attributes, etc. spawns a tree of objects.
87 *
88 * @param v Visitor object
89 */
90 public void accept( Visitor v ) {
91 v.visitExceptionTable(this);
92 }
93
94
95 /***
96 * Dump exceptions attribute to file stream in binary format.
97 *
98 * @param file Output file stream
99 * @throws IOException
100 */
101 public final void dump( DataOutputStream file ) throws IOException {
102 super.dump(file);
103 file.writeShort(number_of_exceptions);
104 for (int i = 0; i < number_of_exceptions; i++) {
105 file.writeShort(exception_index_table[i]);
106 }
107 }
108
109
110 /***
111 * @return Array of indices into constant pool of thrown exceptions.
112 */
113 public final int[] getExceptionIndexTable() {
114 return exception_index_table;
115 }
116
117
118 /***
119 * @return Length of exception table.
120 */
121 public final int getNumberOfExceptions() {
122 return number_of_exceptions;
123 }
124
125
126 /***
127 * @return class names of thrown exceptions
128 */
129 public final String[] getExceptionNames() {
130 String[] names = new String[number_of_exceptions];
131 for (int i = 0; i < number_of_exceptions; i++) {
132 names[i] = constant_pool.getConstantString(exception_index_table[i],
133 Constants.CONSTANT_Class).replace('/', '.');
134 }
135 return names;
136 }
137
138
139 /***
140 * @param exception_index_table the list of exception indexes
141 * Also redefines number_of_exceptions according to table length.
142 */
143 public final void setExceptionIndexTable( int[] exception_index_table ) {
144 this.exception_index_table = exception_index_table;
145 number_of_exceptions = (exception_index_table == null) ? 0 : exception_index_table.length;
146 }
147
148
149 /***
150 * @return String representation, i.e., a list of thrown exceptions.
151 */
152 public final String toString() {
153 StringBuffer buf = new StringBuffer("");
154 String str;
155 for (int i = 0; i < number_of_exceptions; i++) {
156 str = constant_pool.getConstantString(exception_index_table[i],
157 Constants.CONSTANT_Class);
158 buf.append(Utility.compactClassName(str, false));
159 if (i < number_of_exceptions - 1) {
160 buf.append(", ");
161 }
162 }
163 return buf.toString();
164 }
165
166
167 /***
168 * @return deep copy of this attribute
169 */
170 public Attribute copy( ConstantPool _constant_pool ) {
171 ExceptionTable c = (ExceptionTable) clone();
172 if (exception_index_table != null) {
173 c.exception_index_table = new int[exception_index_table.length];
174 System.arraycopy(exception_index_table, 0, c.exception_index_table, 0,
175 exception_index_table.length);
176 }
177 c.constant_pool = _constant_pool;
178 return c;
179 }
180 }