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