    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.archivers.zip;
    018
    019import java.util.zip.ZipException;
    020
    021import org.apache.commons.compress.utils.ByteUtils;
    022
    023/**
    024 * If this extra field is added as the very first extra field of the archive, Solaris will consider it an executable jar file.
    025 *
    026 * @Immutable
    027 */
    028public final class JarMarker implements ZipExtraField {
    029
    030    static final ZipShort ID = new ZipShort(0xCAFE);
    031    private static final ZipShort NULL = new ZipShort(0);
    032    private static final JarMarker DEFAULT = new JarMarker();
    033
    034    /**
    035     * Since JarMarker is stateless we can always use the same instance.
    036     *
    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 length specifier.
    050     *
    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 Header-ID or length specifier.
    060     *
    061     * @return 0
    062     */
    063    @Override
    064    public ZipShort getCentralDirectoryLength() {
    065        return NULL;
    066    }
    067
    068    /**
    069     * The Header-ID.
    070     *
    071     * @return the header id
    072     */
    073    @Override
    074    public ZipShort getHeaderId() {
    075        return ID;
    076    }
    077
    078    /**
    079     * The actual data to put into local file data - without Header-ID or length specifier.
    080     *
    081     * @return the data
    082     */
    083    @Override
    084    public byte[] getLocalFileDataData() {
    085        return ByteUtils.EMPTY_BYTE_ARRAY;
    086    }
    087
    088    /**
    089     * Length of the extra field in the local file data - without Header-ID or length specifier.
    090     *
    091     * @return 0
    092     */
    093    @Override
    094    public ZipShort getLocalFileDataLength() {
    095        return NULL;
    096    }
    097
    098    /**
    099     * Doesn't do anything special since this class always uses the same data in central directory and local file data.
    100     */
    101    @Override
    102    public void parseFromCentralDirectoryData(final byte[] buffer, final int offset, final int length) throws ZipException {
    103        parseFromLocalFileData(buffer, offset, length);
    104    }
    105
    106    /**
    107     * Populate data from this array as if it was in local file data.
    108     *
    109     * @param data   an array of bytes
    110     * @param offset the start offset
    111     * @param length the number of bytes in the array from offset
    112     *
    113     * @throws ZipException on error
    114     */
    115    @Override
    116    public void parseFromLocalFileData(final byte[] data, final int offset, final int length) throws ZipException {
    117        if (length != 0) {
    118            throw new ZipException("JarMarker doesn't expect any data");
    119        }
    120    }
    121}