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