    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 *
    017 */
    018package org.apache.commons.compress.archivers.zip;
    019
    020import java.util.zip.ZipException;
    021
    022import org.apache.commons.compress.utils.ByteUtils;
    023
    024/**
    025 * If this extra field is added as the very first extra field of the
    026 * archive, Solaris will consider it an executable jar file.
    027 * @Immutable
    028 */
    029public final class JarMarker implements ZipExtraField {
    030
    031    private static final ZipShort ID = new ZipShort(0xCAFE);
    032    private static final ZipShort NULL = new ZipShort(0);
    033    private static final JarMarker DEFAULT = new JarMarker();
    034
    035    /**
    036     * Since JarMarker is stateless we can always use the same instance.
    037     * @return the DEFAULT jarmaker.
    038     */
    039    public static JarMarker getInstance() {
    040        return DEFAULT;
    041    }
    042
    043    /** No-arg constructor */
    044    public JarMarker() {
    045        // empty
    046    }
    047
    048    /**
    049     * The actual data to put central directory - without Header-ID or
    050     * length specifier.
    051     * @return the data
    052     */
    053    @Override
    054    public byte[] getCentralDirectoryData() {
    055        return ByteUtils.EMPTY_BYTE_ARRAY;
    056    }
    057
    058    /**
    059     * Length of the extra field in the central directory - without
    060     * Header-ID or length specifier.
    061     * @return 0
    062     */
    063    @Override
    064    public ZipShort getCentralDirectoryLength() {
    065        return NULL;
    066    }
    067
    068    /**
    069     * The Header-ID.
    070     * @return the header id
    071     */
    072    @Override
    073    public ZipShort getHeaderId() {
    074        return ID;
    075    }
    076
    077    /**
    078     * The actual data to put into local file data - without Header-ID
    079     * or length specifier.
    080     * @return the data
    081     */
    082    @Override
    083    public byte[] getLocalFileDataData() {
    084        return ByteUtils.EMPTY_BYTE_ARRAY;
    085    }
    086
    087    /**
    088     * Length of the extra field in the local file data - without
    089     * Header-ID or length specifier.
    090     * @return 0
    091     */
    092    @Override
    093    public ZipShort getLocalFileDataLength() {
    094        return NULL;
    095    }
    096
    097    /**
    098     * Doesn't do anything special since this class always uses the
    099     * same data in central directory and local file data.
    100     */
    101    @Override
    102    public void parseFromCentralDirectoryData(final byte[] buffer, final int offset,
    103                                              final int length)
    104        throws ZipException {
    105        parseFromLocalFileData(buffer, offset, length);
    106    }
    107
    108    /**
    109     * Populate data from this array as if it was in local file data.
    110     * @param data an array of bytes
    111     * @param offset the start offset
    112     * @param length the number of bytes in the array from offset
    113     *
    114     * @throws ZipException on error
    115     */
    116    @Override
    117    public void parseFromLocalFileData(final byte[] data, final int offset, final int length)
    118        throws ZipException {
    119        if (length != 0) {
    120            throw new ZipException("JarMarker doesn't expect any data");
    121        }
    122    }
    123}