    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
    069     * attribute length). This is relevant when attributes are nested within other attributes - the outer attribute
    070     * needs to take the inner attribute headers into account when calculating its length.
    071     *
    072     * @return int adjusted length
    073     */
    074    protected int getLengthIncludingHeader() {
    075        return getLength() + 2 + 4;
    076    }
    077
    078    @Override
    079    protected ClassFileEntry[] getNestedClassFileEntries() {
    080        return new ClassFileEntry[] {getAttributeName()};
    081    }
    082
    083    /**
    084     * Answer true if the receiver needs to have BCI renumbering applied to it; otherwise answer false.
    085     *
    086     * @return boolean BCI renumbering required
    087     */
    088    public boolean hasBCIRenumbering() {
    089        return false;
    090    }
    091
    092    @Override
    093    public int hashCode() {
    094        return Objects.hash(attributeName);
    095    }
    096
    097    /**
    098     * Answer true if the receiver is a source file attribute (which gets special handling when the class is built);
    099     * otherwise answer false.
    100     *
    101     * @return boolean source file attribute
    102     */
    103    public boolean isSourceFileAttribute() {
    104        return false;
    105    }
    106
    107    @Override
    108    protected void resolve(final ClassConstantPool pool) {
    109        super.resolve(pool);
    110        attributeNameIndex = pool.indexOf(attributeName);
    111    }
    112
    113    protected abstract void writeBody(DataOutputStream dos) throws IOException;
    114
    115}