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 the abstract {@link Constant} and represents a reference to a module. 028 * 029 * <p> 030 * Note: Early access Java 9 support- currently subject to change 031 * </p> 032 * 033 * @see Constant 034 * @since 6.1 035 */ 036public final class ConstantModule extends Constant implements ConstantObject { 037 038 private int nameIndex; 039 040 /** 041 * Initialize from another object. 042 */ 043 public ConstantModule(final ConstantModule c) { 044 this(c.getNameIndex()); 045 } 046 047 /** 048 * Initialize instance from file data. 049 * 050 * @param file Input stream 051 * @throws IOException if an I/O error occurs. 052 */ 053 ConstantModule(final DataInput file) throws IOException { 054 this(file.readUnsignedShort()); 055 } 056 057 /** 058 * @param nameIndex Name index in constant pool. Should refer to a ConstantUtf8. 059 */ 060 public ConstantModule(final int nameIndex) { 061 super(Const.CONSTANT_Module); 062 this.nameIndex = nameIndex; 063 } 064 065 /** 066 * Called by objects that are traversing the nodes of the tree implicitly defined by the contents of a Java class. I.e., 067 * the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. 068 * 069 * @param v Visitor object 070 */ 071 @Override 072 public void accept(final Visitor v) { 073 v.visitConstantModule(this); 074 } 075 076 /** 077 * Dump constant module to file stream in binary format. 078 * 079 * @param file Output file stream 080 * @throws IOException if an I/O error occurs. 081 */ 082 @Override 083 public void dump(final DataOutputStream file) throws IOException { 084 file.writeByte(super.getTag()); 085 file.writeShort(nameIndex); 086 } 087 088 /** 089 * @return dereferenced string 090 */ 091 public String getBytes(final ConstantPool cp) { 092 return (String) getConstantValue(cp); 093 } 094 095 /** 096 * @return String object 097 */ 098 @Override 099 public Object getConstantValue(final ConstantPool cp) { 100 return cp.getConstantUtf8(nameIndex).getBytes(); 101 } 102 103 /** 104 * @return Name index in constant pool of module name. 105 */ 106 public int getNameIndex() { 107 return nameIndex; 108 } 109 110 /** 111 * @param nameIndex the name index in the constant pool of this Constant Module 112 */ 113 public void setNameIndex(final int nameIndex) { 114 this.nameIndex = nameIndex; 115 } 116 117 /** 118 * @return String representation. 119 */ 120 @Override 121 public String toString() { 122 return super.toString() + "(nameIndex = " + nameIndex + ")"; 123 } 124}