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 reference constant pool entries, such as a method or field reference.
025 */
026public abstract class CPRef extends ConstantPoolEntry {
027
028    CPClass className;
029    transient int classNameIndex;
030
031    protected CPNameAndType nameAndType;
032    transient int nameAndTypeIndex;
033
034    protected String cachedToString;
035
036    /**
037     * Constructs a new CPRef.
038     *
039     * @param type        TODO
040     * @param className   TODO
041     * @param descriptor  TODO
042     * @param globalIndex index in CpBands
043     * @throws NullPointerException if descriptor or className is null
044     */
045    public CPRef(final byte type, final CPClass className, final CPNameAndType descriptor, final int globalIndex) {
046        super(type, globalIndex);
047        this.className = Objects.requireNonNull(className, "className");
048        this.nameAndType = Objects.requireNonNull(descriptor, "descriptor");
049    }
050
051    @Override
052    public boolean equals(final Object obj) {
053        if (this == obj) {
054            return true;
055        }
056        if (obj == null) {
057            return false;
058        }
059        if (getClass() != obj.getClass()) {
060            return false;
061        }
062        if (hashCode() != obj.hashCode()) {
063            return false;
064        }
065        final CPRef other = (CPRef) obj;
066        return Objects.equals(className, other.className)
067                && Objects.equals(nameAndType, other.nameAndType);
068    }
069
070    @Override
071    protected ClassFileEntry[] getNestedClassFileEntries() {
072        final ClassFileEntry[] entries = new ClassFileEntry[2];
073        entries[0] = className;
074        entries[1] = nameAndType;
075        return entries;
076    }
077
078    @Override
079    protected void resolve(final ClassConstantPool pool) {
080        super.resolve(pool);
081        nameAndTypeIndex = pool.indexOf(nameAndType);
082        classNameIndex = pool.indexOf(className);
083    }
084
085    @Override
086    public String toString() {
087        if (cachedToString == null) {
088            String type;
089            if (getTag() == CP_Fieldref) {
090                type = "FieldRef"; //$NON-NLS-1$
091            } else if (getTag() == CP_Methodref) {
092                type = "MethoddRef"; //$NON-NLS-1$
093            } else if (getTag() == CP_InterfaceMethodref) {
094                type = "InterfaceMethodRef"; //$NON-NLS-1$
095            } else {
096                type = "unknown"; //$NON-NLS-1$
097            }
098            cachedToString = type + ": " + className + "#" + nameAndType; //$NON-NLS-1$ //$NON-NLS-2$
099        }
100        return cachedToString;
101    }
102
103    @Override
104    protected void writeBody(final DataOutputStream dos) throws IOException {
105        dos.writeShort(classNameIndex);
106        dos.writeShort(nameAndTypeIndex);
107    }
108
109}