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 is derived from <em>Attribute</em> and records the nest host of the nest 028 * to which the current class or interface claims to belong. 029 * There may be at most one NestHost attribute in a ClassFile structure. 030 * 031 * @see Attribute 032 */ 033public final class NestHost extends Attribute { 034 035 private int host_class_index; 036 037 038 /** 039 * Initializes from another object. Note that both objects use the same 040 * references (shallow copy). Use copy() for a physical copy. 041 */ 042 public NestHost(final NestHost c) { 043 this(c.getNameIndex(), c.getLength(), c.getHostClassIndex(), c.getConstantPool()); 044 } 045 046 047 /** 048 * @param name_index Index in constant pool 049 * @param length Content length in bytes 050 * @param host_class_index Host class index 051 * @param constant_pool Array of constants 052 */ 053 public NestHost(final int name_index, final int length, final int host_class_index, 054 final ConstantPool constant_pool) { 055 super(Const.ATTR_NEST_MEMBERS, name_index, length, constant_pool); 056 this.host_class_index = host_class_index; 057 } 058 059 060 /** 061 * Constructs object from input stream. 062 * @param name_index Index in constant pool 063 * @param length Content length in bytes 064 * @param input Input stream 065 * @param constant_pool Array of constants 066 * @throws IOException 067 */ 068 NestHost(final int name_index, final int length, final DataInput input, final ConstantPool constant_pool) throws IOException { 069 this(name_index, length, 0, constant_pool); 070 host_class_index = input.readUnsignedShort(); 071 } 072 073 074 /** 075 * Called by objects that are traversing the nodes of the tree implicitely 076 * defined by the contents of a Java class. I.e., the hierarchy of methods, 077 * fields, attributes, etc. spawns a tree of objects. 078 * 079 * @param v Visitor object 080 */ 081 @Override 082 public void accept( final Visitor v ) { 083 v.visitNestHost(this); 084 } 085 086 087 /** 088 * Dumps NestHost attribute to file stream in binary format. 089 * 090 * @param file Output file stream 091 * @throws IOException if an I/O error occurs. 092 */ 093 @Override 094 public void dump( final DataOutputStream file ) throws IOException { 095 super.dump(file); 096 file.writeShort(host_class_index); 097 } 098 099 100 /** 101 * @return index into constant pool of host class name. 102 */ 103 public int getHostClassIndex() { 104 return host_class_index; 105 } 106 107 108 /** 109 * @param host_class_index the host class index 110 */ 111 public void setHostClassIndex( final int host_class_index ) { 112 this.host_class_index = host_class_index; 113 } 114 115 116 /** 117 * @return String representation 118 */ 119 @Override 120 public String toString() { 121 final StringBuilder buf = new StringBuilder(); 122 buf.append("NestHost: "); 123 final String class_name = super.getConstantPool().getConstantString(host_class_index, Const.CONSTANT_Class); 124 buf.append(Utility.compactClassName(class_name, false)); 125 return buf.toString(); 126 } 127 128 129 /** 130 * @return deep copy of this attribute 131 */ 132 @Override 133 public Attribute copy( final ConstantPool _constant_pool ) { 134 final NestHost c = (NestHost) clone(); 135 c.setConstantPool(_constant_pool); 136 return c; 137 } 138}