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