    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
    025 * archive, Solaris will consider it an executable jar file.
    026 * @Immutable
    027 */
    028public final class JarMarker implements ZipExtraField {
    029
    030    private 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     * @return the DEFAULT jarmaker.
    037     */
    038    public static JarMarker getInstance() {
    039        return DEFAULT;
    040    }
    041
    042    /** No-arg constructor */
    043    public JarMarker() {
    044        // empty
    045    }
    046
    047    /**
    048     * The actual data to put central directory - without Header-ID or
    049     * length specifier.
    050     * @return the data
    051     */
    052    @Override
    053    public byte[] getCentralDirectoryData() {
    054        return ByteUtils.EMPTY_BYTE_ARRAY;
    055    }
    056
    057    /**
    058     * Length of the extra field in the central directory - without
    059     * Header-ID or length specifier.
    060     * @return 0
    061     */
    062    @Override
    063    public ZipShort getCentralDirectoryLength() {
    064        return NULL;
    065    }
    066
    067    /**
    068     * The Header-ID.
    069     * @return the header id
    070     */
    071    @Override
    072    public ZipShort getHeaderId() {
    073        return ID;
    074    }
    075
    076    /**
    077     * The actual data to put into local file data - without Header-ID
    078     * or length specifier.
    079     * @return the data
    080     */
    081    @Override
    082    public byte[] getLocalFileDataData() {
    083        return ByteUtils.EMPTY_BYTE_ARRAY;
    084    }
    085
    086    /**
    087     * Length of the extra field in the local file data - without
    088     * Header-ID or length specifier.
    089     * @return 0
    090     */
    091    @Override
    092    public ZipShort getLocalFileDataLength() {
    093        return NULL;
    094    }
    095
    096    /**
    097     * Doesn't do anything special since this class always uses the
    098     * same data in central directory and local file data.
    099     */
    100    @Override
    101    public void parseFromCentralDirectoryData(final byte[] buffer, final int offset,
    102                                              final int length)
    103        throws ZipException {
    104        parseFromLocalFileData(buffer, offset, length);
    105    }
    106
    107    /**
    108     * Populate data from this array as if it was in local file data.
    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)
    117        throws ZipException {
    118        if (length != 0) {
    119            throw new ZipException("JarMarker doesn't expect any data");
    120        }
    121    }
    122}