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 * Field reference constant pool entry.
025 */
026public class CPFieldRef extends ConstantPoolEntry {
027
028    CPClass className;
029    transient int classNameIndex;
030    private final CPNameAndType nameAndType;
031    transient int nameAndTypeIndex;
032
033    private boolean hashCodeComputed;
034
035    private int cachedHashCode;
036
037    public CPFieldRef(final CPClass className, final CPNameAndType descriptor, final int globalIndex) {
038        super(CP_Fieldref, globalIndex);
039        this.className = className;
040        this.nameAndType = descriptor;
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 (getClass() != obj.getClass()) {
052            return false;
053        }
054        final CPFieldRef other = (CPFieldRef) obj;
055        return Objects.equals(className, other.className)
056                && Objects.equals(nameAndType, other.nameAndType);
057    }
058
059    private void generateHashCode() {
060        hashCodeComputed = true;
061        final int PRIME = 31;
062        int result = 1;
063        result = PRIME * result + (className == null ? 0 : className.hashCode());
064        result = PRIME * result + (nameAndType == null ? 0 : nameAndType.hashCode());
065        cachedHashCode = result;
066    }
067
068    @Override
069    protected ClassFileEntry[] getNestedClassFileEntries() {
070        return new ClassFileEntry[] { className, nameAndType };
071    }
072
073    @Override
074    public int hashCode() {
075        if (!hashCodeComputed) {
076            generateHashCode();
077        }
078        return cachedHashCode;
079    }
080
081    @Override
082    protected void resolve(final ClassConstantPool pool) {
083        super.resolve(pool);
084        nameAndTypeIndex = pool.indexOf(nameAndType);
085        classNameIndex = pool.indexOf(className);
086    }
087
088    @Override
089    public String toString() {
090        return "FieldRef: " + className + "#" + nameAndType;
091    }
092
093    @Override
094    protected void writeBody(final DataOutputStream dos) throws IOException {
095        dos.writeShort(classNameIndex);
096        dos.writeShort(nameAndTypeIndex);
097    }
098
099}