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 */ 017package org.apache.commons.compress.harmony.unpack200.bytecode; 018 019import java.io.DataOutputStream; 020import java.io.IOException; 021 022/** 023 * Abstract superclass for class file attributes 024 */ 025public abstract class Attribute extends ClassFileEntry { 026 027 protected final CPUTF8 attributeName; 028 029 private int attributeNameIndex; 030 031 public Attribute(final CPUTF8 attributeName) { 032 this.attributeName = attributeName; 033 } 034 035 @Override 036 protected void doWrite(final DataOutputStream dos) throws IOException { 037 dos.writeShort(attributeNameIndex); 038 dos.writeInt(getLength()); 039 writeBody(dos); 040 } 041 042 @Override 043 public boolean equals(final Object obj) { 044 if (this == obj) { 045 return true; 046 } 047 if (obj == null) { 048 return false; 049 } 050 if (this.getClass() != obj.getClass()) { 051 return false; 052 } 053 final Attribute other = (Attribute) obj; 054 if (attributeName == null) { 055 if (other.attributeName != null) { 056 return false; 057 } 058 } else if (!attributeName.equals(other.attributeName)) { 059 return false; 060 } 061 return true; 062 } 063 064 protected CPUTF8 getAttributeName() { 065 return attributeName; 066 } 067 068 protected abstract int getLength(); 069 070 /** 071 * Answer the length of the receiver including its header (the u2 for the attribute name and the u4 for the 072 * attribute length). This is relevant when attributes are nested within other attributes - the outer attribute 073 * needs to take the inner attribute headers into account when calculating its length. 074 * 075 * @return int adjusted length 076 */ 077 protected int getLengthIncludingHeader() { 078 return getLength() + 2 + 4; 079 } 080 081 @Override 082 protected ClassFileEntry[] getNestedClassFileEntries() { 083 return new ClassFileEntry[] {getAttributeName()}; 084 } 085 086 /** 087 * Answer true if the receiver needs to have BCI renumbering applied to it; otherwise answer false. 088 * 089 * @return boolean BCI renumbering required 090 */ 091 public boolean hasBCIRenumbering() { 092 return false; 093 } 094 095 /** 096 * Answer true if the receiver is a source file attribute (which gets special handling when the class is built); 097 * otherwise answer false. 098 * 099 * @return boolean source file attribute 100 */ 101 public boolean isSourceFileAttribute() { 102 return false; 103 } 104 105 @Override 106 public int hashCode() { 107 final int PRIME = 31; 108 int result = 1; 109 result = PRIME * result + ((attributeName == null) ? 0 : attributeName.hashCode()); 110 return result; 111 } 112 113 @Override 114 protected void resolve(final ClassConstantPool pool) { 115 super.resolve(pool); 116 attributeNameIndex = pool.indexOf(attributeName); 117 } 118 119 protected abstract void writeBody(DataOutputStream dos) throws IOException; 120 121}