001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 *
017 */
018 package org.apache.bcel.classfile;
019
020 import java.io.DataInputStream;
021 import java.io.DataOutputStream;
022 import java.io.IOException;
023 import org.apache.bcel.Constants;
024
025 /**
026 * This class represents the table of exceptions that are thrown by a
027 * method. This attribute may be used once per method. The name of
028 * this class is <em>ExceptionTable</em> for historical reasons; The
029 * Java Virtual Machine Specification, Second Edition defines this
030 * attribute using the name <em>Exceptions</em> (which is inconsistent
031 * with the other classes).
032 *
033 * @version $Id: ExceptionTable.java 1152077 2011-07-29 02:29:42Z dbrosius $
034 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
035 * @see Code
036 */
037 public final class ExceptionTable extends Attribute {
038
039 private static final long serialVersionUID = 2045358830660883220L;
040 private int number_of_exceptions; // Table of indices into
041 private int[] exception_index_table; // constant pool
042
043
044 /**
045 * Initialize from another object. Note that both objects use the same
046 * references (shallow copy). Use copy() for a physical copy.
047 */
048 public ExceptionTable(ExceptionTable c) {
049 this(c.getNameIndex(), c.getLength(), c.getExceptionIndexTable(), c.getConstantPool());
050 }
051
052
053 /**
054 * @param name_index Index in constant pool
055 * @param length Content length in bytes
056 * @param exception_index_table Table of indices in constant pool
057 * @param constant_pool Array of constants
058 */
059 public ExceptionTable(int name_index, int length, int[] exception_index_table,
060 ConstantPool constant_pool) {
061 super(Constants.ATTR_EXCEPTIONS, name_index, length, constant_pool);
062 setExceptionIndexTable(exception_index_table);
063 }
064
065
066 /**
067 * Construct object from file stream.
068 * @param name_index Index in constant pool
069 * @param length Content length in bytes
070 * @param file Input stream
071 * @param constant_pool Array of constants
072 * @throws IOException
073 */
074 ExceptionTable(int name_index, int length, DataInputStream file, ConstantPool constant_pool)
075 throws IOException {
076 this(name_index, length, (int[]) null, constant_pool);
077 number_of_exceptions = file.readUnsignedShort();
078 exception_index_table = new int[number_of_exceptions];
079 for (int i = 0; i < number_of_exceptions; i++) {
080 exception_index_table[i] = file.readUnsignedShort();
081 }
082 }
083
084
085 /**
086 * Called by objects that are traversing the nodes of the tree implicitely
087 * defined by the contents of a Java class. I.e., the hierarchy of methods,
088 * fields, attributes, etc. spawns a tree of objects.
089 *
090 * @param v Visitor object
091 */
092 @Override
093 public void accept( Visitor v ) {
094 v.visitExceptionTable(this);
095 }
096
097
098 /**
099 * Dump exceptions attribute to file stream in binary format.
100 *
101 * @param file Output file stream
102 * @throws IOException
103 */
104 @Override
105 public final void dump( DataOutputStream file ) throws IOException {
106 super.dump(file);
107 file.writeShort(number_of_exceptions);
108 for (int i = 0; i < number_of_exceptions; i++) {
109 file.writeShort(exception_index_table[i]);
110 }
111 }
112
113
114 /**
115 * @return Array of indices into constant pool of thrown exceptions.
116 */
117 public final int[] getExceptionIndexTable() {
118 return exception_index_table;
119 }
120
121
122 /**
123 * @return Length of exception table.
124 */
125 public final int getNumberOfExceptions() {
126 return number_of_exceptions;
127 }
128
129
130 /**
131 * @return class names of thrown exceptions
132 */
133 public final String[] getExceptionNames() {
134 String[] names = new String[number_of_exceptions];
135 for (int i = 0; i < number_of_exceptions; i++) {
136 names[i] = constant_pool.getConstantString(exception_index_table[i],
137 Constants.CONSTANT_Class).replace('/', '.');
138 }
139 return names;
140 }
141
142
143 /**
144 * @param exception_index_table the list of exception indexes
145 * Also redefines number_of_exceptions according to table length.
146 */
147 public final void setExceptionIndexTable( int[] exception_index_table ) {
148 this.exception_index_table = exception_index_table;
149 number_of_exceptions = (exception_index_table == null) ? 0 : exception_index_table.length;
150 }
151
152
153 /**
154 * @return String representation, i.e., a list of thrown exceptions.
155 */
156 @Override
157 public final String toString() {
158 StringBuilder buf = new StringBuilder();
159 String str;
160 for (int i = 0; i < number_of_exceptions; i++) {
161 str = constant_pool.getConstantString(exception_index_table[i],
162 Constants.CONSTANT_Class);
163 buf.append(Utility.compactClassName(str, false));
164 if (i < number_of_exceptions - 1) {
165 buf.append(", ");
166 }
167 }
168 return buf.toString();
169 }
170
171
172 /**
173 * @return deep copy of this attribute
174 */
175 @Override
176 public Attribute copy( ConstantPool _constant_pool ) {
177 ExceptionTable c = (ExceptionTable) clone();
178 if (exception_index_table != null) {
179 c.exception_index_table = new int[exception_index_table.length];
180 System.arraycopy(exception_index_table, 0, c.exception_index_table, 0,
181 exception_index_table.length);
182 }
183 c.constant_pool = _constant_pool;
184 return c;
185 }
186 }