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 * An {@link Attribute} representing a constant.
024 */
025public class ConstantValueAttribute extends Attribute {
026
027    private int constantIndex;
028
029    private final ClassFileEntry entry;
030
031    private static CPUTF8 attributeName;
032
033    public static void setAttributeName(final CPUTF8 cpUTF8Value) {
034        attributeName = cpUTF8Value;
035    }
036
037    public ConstantValueAttribute(final ClassFileEntry entry) {
038        super(attributeName);
039        if (entry == null) {
040            throw new NullPointerException();
041        }
042        this.entry = entry;
043    }
044
045    @Override
046    public boolean equals(final Object obj) {
047        if (this == obj) {
048            return true;
049        }
050        if (!super.equals(obj)) {
051            return false;
052        }
053        if (this.getClass() != obj.getClass()) {
054            return false;
055        }
056        final ConstantValueAttribute other = (ConstantValueAttribute) obj;
057        if (entry == null) {
058            if (other.entry != null) {
059                return false;
060            }
061        } else if (!entry.equals(other.entry)) {
062            return false;
063        }
064        return true;
065    }
066
067    @Override
068    protected int getLength() {
069        return 2;
070    }
071
072    @Override
073    protected ClassFileEntry[] getNestedClassFileEntries() {
074        return new ClassFileEntry[] {getAttributeName(), entry};
075    }
076
077    @Override
078    public int hashCode() {
079        final int PRIME = 31;
080        int result = super.hashCode();
081        result = PRIME * result + ((entry == null) ? 0 : entry.hashCode());
082        return result;
083    }
084
085    @Override
086    protected void resolve(final ClassConstantPool pool) {
087        super.resolve(pool);
088        entry.resolve(pool);
089        this.constantIndex = pool.indexOf(entry);
090    }
091
092    @Override
093    public String toString() {
094        return "Constant:" + entry;
095    }
096
097    @Override
098    protected void writeBody(final DataOutputStream dos) throws IOException {
099        dos.writeShort(constantIndex);
100    }
101
102}