com.itextpdf.kernel.pdf.filters.FilterHandlers Maven / Gradle / Ivy

/*

    This file is part of the iText (R) project.
    Copyright (c) 1998-2019 iText Group NV
    Authors: Bruno Lowagie, Paulo Soares, et al.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License version 3
    as published by the Free Software Foundation with the addition of the
    following permission added to Section 15 as permitted in Section 7(a):
    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
    OF THIRD PARTY RIGHTS

    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE.
    See the GNU Affero General Public License for more details.
    You should have received a copy of the GNU Affero General Public License
    along with this program; if not, see http://www.gnu.org/licenses or write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA, 02110-1301 USA, or download the license from the following URL:
    http://itextpdf.com/terms-of-use/

    The interactive user interfaces in modified source and object code versions
    of this program must display Appropriate Legal Notices, as required under
    Section 5 of the GNU Affero General Public License.

    In accordance with Section 7(b) of the GNU Affero General Public License,
    a covered work must retain the producer line in every PDF that is created
    or manipulated using iText.

    You can be released from the requirements of the license by purchasing
    a commercial license. Buying such a license is mandatory as soon as you
    develop commercial activities involving the iText software without
    disclosing the source code of your own applications.
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 */
package com.itextpdf.kernel.pdf.filters;

import com.itextpdf.kernel.pdf.PdfName;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * Encapsulates filter behavior for PDF streams.  Classes generally interace with this
 * using the static getDefaultFilterHandlers() method, then obtain the desired {@link IFilterHandler}
 * via a lookup.
 */
// Dev note:  we eventually want to refactor PdfReader so all of the existing filter functionality is moved into this class
// it may also be better to split the sub-classes out into a separate package
public final class FilterHandlers {

    /** The default {@link IFilterHandler}s used by iText */
    private static final Map defaults;
    static {
        Map map = new HashMap<>();

        map.put(PdfName.FlateDecode, new FlateDecodeFilter());
        map.put(PdfName.Fl, new FlateDecodeFilter());
        map.put(PdfName.ASCIIHexDecode, new ASCIIHexDecodeFilter());
        map.put(PdfName.AHx, new ASCIIHexDecodeFilter());
        map.put(PdfName.ASCII85Decode, new ASCII85DecodeFilter());
        map.put(PdfName.A85, new ASCII85DecodeFilter());
        map.put(PdfName.LZWDecode, new LZWDecodeFilter());
        map.put(PdfName.CCITTFaxDecode, new CCITTFaxDecodeFilter());
        map.put(PdfName.Crypt, new DoNothingFilter());
        map.put(PdfName.RunLengthDecode, new RunLengthDecodeFilter());

        defaults = Collections.unmodifiableMap(map);
    }

    /**
     * @return the default {@link IFilterHandler}s used by iText
     */
    public static Map getDefaultFilterHandlers(){
        return defaults;
    }
}