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 018package org.apache.bcel.classfile; 019 020import java.io.DataInput; 021import java.io.DataOutputStream; 022import java.io.IOException; 023 024import org.apache.bcel.Const; 025 026/** 027 * This class represents the table of exceptions that are thrown by a 028 * method. This attribute may be used once per method. The name of 029 * this class is <em>ExceptionTable</em> for historical reasons; The 030 * Java Virtual Machine Specification, Second Edition defines this 031 * attribute using the name <em>Exceptions</em> (which is inconsistent 032 * with the other classes). 033 * 034 * @see Code 035 */ 036public final class ExceptionTable extends Attribute { 037 038 private int[] exception_index_table; // constant pool 039 040 041 /** 042 * Initialize from another object. Note that both objects use the same 043 * references (shallow copy). Use copy() for a physical copy. 044 */ 045 public ExceptionTable(final ExceptionTable c) { 046 this(c.getNameIndex(), c.getLength(), c.getExceptionIndexTable(), c.getConstantPool()); 047 } 048 049 050 /** 051 * @param name_index Index in constant pool 052 * @param length Content length in bytes 053 * @param exception_index_table Table of indices in constant pool 054 * @param constant_pool Array of constants 055 */ 056 public ExceptionTable(final int name_index, final int length, final int[] exception_index_table, 057 final ConstantPool constant_pool) { 058 super(Const.ATTR_EXCEPTIONS, name_index, length, constant_pool); 059 this.exception_index_table = exception_index_table != null ? exception_index_table : new int[0]; 060 } 061 062 063 /** 064 * Construct object from input stream. 065 * @param name_index Index in constant pool 066 * @param length Content length in bytes 067 * @param input Input stream 068 * @param constant_pool Array of constants 069 * @throws IOException 070 */ 071 ExceptionTable(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException { 072 this(name_index, length, (int[]) null, constant_pool); 073 final int number_of_exceptions = input.readUnsignedShort(); 074 exception_index_table = new int[number_of_exceptions]; 075 for (int i = 0; i < number_of_exceptions; i++) { 076 exception_index_table[i] = input.readUnsignedShort(); 077 } 078 } 079 080 081 /** 082 * Called by objects that are traversing the nodes of the tree implicitely 083 * defined by the contents of a Java class. I.e., the hierarchy of methods, 084 * fields, attributes, etc. spawns a tree of objects. 085 * 086 * @param v Visitor object 087 */ 088 @Override 089 public void accept( final Visitor v ) { 090 v.visitExceptionTable(this); 091 } 092 093 094 /** 095 * Dump exceptions attribute to file stream in binary format. 096 * 097 * @param file Output file stream 098 * @throws IOException 099 */ 100 @Override 101 public void dump( final DataOutputStream file ) throws IOException { 102 super.dump(file); 103 file.writeShort(exception_index_table.length); 104 for (final int index : exception_index_table) { 105 file.writeShort(index); 106 } 107 } 108 109 110 /** 111 * @return Array of indices into constant pool of thrown exceptions. 112 */ 113 public int[] getExceptionIndexTable() { 114 return exception_index_table; 115 } 116 117 118 /** 119 * @return Length of exception table. 120 */ 121 public int getNumberOfExceptions() { 122 return exception_index_table == null ? 0 : exception_index_table.length; 123 } 124 125 126 /** 127 * @return class names of thrown exceptions 128 */ 129 public String[] getExceptionNames() { 130 final String[] names = new String[exception_index_table.length]; 131 for (int i = 0; i < exception_index_table.length; i++) { 132 names[i] = super.getConstantPool().getConstantString(exception_index_table[i], 133 Const.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 void setExceptionIndexTable( final int[] exception_index_table ) { 144 this.exception_index_table = exception_index_table != null ? exception_index_table : new int[0]; 145 } 146 147 148 /** 149 * @return String representation, i.e., a list of thrown exceptions. 150 */ 151 @Override 152 public String toString() { 153 final StringBuilder buf = new StringBuilder(); 154 String str; 155 buf.append("Exceptions: "); 156 for (int i = 0; i < exception_index_table.length; i++) { 157 str = super.getConstantPool().getConstantString(exception_index_table[i], Const.CONSTANT_Class); 158 buf.append(Utility.compactClassName(str, false)); 159 if (i < exception_index_table.length - 1) { 160 buf.append(", "); 161 } 162 } 163 return buf.toString(); 164 } 165 166 167 /** 168 * @return deep copy of this attribute 169 */ 170 @Override 171 public Attribute copy( final ConstantPool _constant_pool ) { 172 final ExceptionTable c = (ExceptionTable) clone(); 173 if (exception_index_table != null) { 174 c.exception_index_table = new int[exception_index_table.length]; 175 System.arraycopy(exception_index_table, 0, c.exception_index_table, 0, 176 exception_index_table.length); 177 } 178 c.setConstantPool(_constant_pool); 179 return c; 180 } 181}