1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.bcel.classfile; 19 20 import java.io.DataInput; 21 import java.io.DataOutputStream; 22 import java.io.IOException; 23 24 import org.apache.bcel.Const; 25 26 /** 27 * This class represents the table of exceptions that are thrown by a 28 * method. This attribute may be used once per method. The name of 29 * this class is <em>ExceptionTable</em> for historical reasons; The 30 * Java Virtual Machine Specification, Second Edition defines this 31 * attribute using the name <em>Exceptions</em> (which is inconsistent 32 * with the other classes). 33 * 34 * @version $Id$ 35 * @see Code 36 */ 37 public final class ExceptionTable extends Attribute { 38 39 private int[] exception_index_table; // constant pool 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(final 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(final int name_index, final int length, final int[] exception_index_table, 58 final ConstantPool constant_pool) { 59 super(Const.ATTR_EXCEPTIONS, name_index, length, constant_pool); 60 this.exception_index_table = exception_index_table != null ? exception_index_table : new int[0]; 61 } 62 63 64 /** 65 * Construct object from input stream. 66 * @param name_index Index in constant pool 67 * @param length Content length in bytes 68 * @param input Input stream 69 * @param constant_pool Array of constants 70 * @throws IOException 71 */ 72 ExceptionTable(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException { 73 this(name_index, length, (int[]) null, constant_pool); 74 final int number_of_exceptions = input.readUnsignedShort(); 75 exception_index_table = new int[number_of_exceptions]; 76 for (int i = 0; i < number_of_exceptions; i++) { 77 exception_index_table[i] = input.readUnsignedShort(); 78 } 79 } 80 81 82 /** 83 * Called by objects that are traversing the nodes of the tree implicitely 84 * defined by the contents of a Java class. I.e., the hierarchy of methods, 85 * fields, attributes, etc. spawns a tree of objects. 86 * 87 * @param v Visitor object 88 */ 89 @Override 90 public void accept( final 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 @Override 102 public final void dump( final DataOutputStream file ) throws IOException { 103 super.dump(file); 104 file.writeShort(exception_index_table.length); 105 for (final int index : exception_index_table) { 106 file.writeShort(index); 107 } 108 } 109 110 111 /** 112 * @return Array of indices into constant pool of thrown exceptions. 113 */ 114 public final int[] getExceptionIndexTable() { 115 return exception_index_table; 116 } 117 118 119 /** 120 * @return Length of exception table. 121 */ 122 public final int getNumberOfExceptions() { 123 return exception_index_table == null ? 0 : exception_index_table.length; 124 } 125 126 127 /** 128 * @return class names of thrown exceptions 129 */ 130 public final String[] getExceptionNames() { 131 final String[] names = new String[exception_index_table.length]; 132 for (int i = 0; i < exception_index_table.length; i++) { 133 names[i] = super.getConstantPool().getConstantString(exception_index_table[i], 134 Const.CONSTANT_Class).replace('/', '.'); 135 } 136 return names; 137 } 138 139 140 /** 141 * @param exception_index_table the list of exception indexes 142 * Also redefines number_of_exceptions according to table length. 143 */ 144 public final void setExceptionIndexTable( final int[] exception_index_table ) { 145 this.exception_index_table = exception_index_table != null ? exception_index_table : new int[0]; 146 } 147 148 149 /** 150 * @return String representation, i.e., a list of thrown exceptions. 151 */ 152 @Override 153 public final String toString() { 154 final StringBuilder buf = new StringBuilder(); 155 String str; 156 buf.append("Exceptions: "); 157 for (int i = 0; i < exception_index_table.length; i++) { 158 str = super.getConstantPool().getConstantString(exception_index_table[i], Const.CONSTANT_Class); 159 buf.append(Utility.compactClassName(str, false)); 160 if (i < exception_index_table.length - 1) { 161 buf.append(", "); 162 } 163 } 164 return buf.toString(); 165 } 166 167 168 /** 169 * @return deep copy of this attribute 170 */ 171 @Override 172 public Attribute copy( final ConstantPool _constant_pool ) { 173 final ExceptionTable c = (ExceptionTable) clone(); 174 if (exception_index_table != null) { 175 c.exception_index_table = new int[exception_index_table.length]; 176 System.arraycopy(exception_index_table, 0, c.exception_index_table, 0, 177 exception_index_table.length); 178 } 179 c.setConstantPool(_constant_pool); 180 return c; 181 } 182 } 183
