001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software GmbH & Co. KG, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.relations;
029
030import org.opencms.file.CmsFile;
031import org.opencms.file.CmsObject;
032
033import java.util.List;
034
035/**
036 * This interface serves to retrieve all links from a given file by parsing.<p>
037 *
038 * Relation validation for a file is only enabled if the file's resource type
039 * implements this interface. so, files with resource types that do not implement
040 * this interface don't get validated for broken links, during publsihing, for
041 * instance.<p>
042 *
043 * This interface is used to build the internal relation information, but it is
044 * not directly used to validate the relations.<p>
045 *
046 * @since 6.3.0
047 */
048public interface I_CmsLinkParseable {
049
050    /**
051     * Returns a list of all links from the specified file.<p>
052     *
053     * Implementations of this method must return an empty list, or better
054     * {@link java.util.Collections#EMPTY_LIST}, if no link is found at all.<p>
055     *
056     * Implementations of this method should return the list of links including internal
057     * (OpenCms VFS) and external links (http, https, mailto, ftp, etc.).<p>
058     *
059     * @param cms the current user's context
060     * @param file the file to be parsed
061     *
062     * @return a list of {@link CmsLink} objects with the URIs of all linked resources
063     */
064    List<CmsLink> parseLinks(CmsObject cms, CmsFile file);
065}