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, 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.ui.contextmenu;
029
030import org.opencms.file.CmsObject;
031import org.opencms.file.CmsResource;
032
033import java.util.List;
034
035/**
036 * Abstract superclass for menu item visibility checks.<p>
037 *
038 * This class automatically handles the case where multiple resources are passed to the getVisibilityMethod.
039 * You just need to implement the getSingleVisibility method in subclasses.
040 */
041public abstract class A_CmsSimpleVisibilityCheck implements I_CmsHasMenuItemVisibility {
042
043    /** Flag to indicate that the check should not match multiple resources. */
044    protected boolean m_singleResourceOnly;
045
046    /**
047     * Computes visibility of the menu item for a single resource.<p>
048     *
049     * @param cms the CMS context to use
050     * @param resource the resource to check
051     *
052     * @return the visibility for the given resource
053     */
054    public abstract CmsMenuItemVisibilityMode getSingleVisibility(CmsObject cms, CmsResource resource);
055
056    /**
057     * @see org.opencms.ui.contextmenu.I_CmsHasMenuItemVisibility#getVisibility(org.opencms.file.CmsObject, java.util.List)
058     */
059    public CmsMenuItemVisibilityMode getVisibility(CmsObject cms, List<CmsResource> resources) {
060
061        if (resources.size() <= 1) {
062            // Single-selection case where we just delegate to getSingleVisibility
063            // this applies also to main menu items
064            return getSingleVisibility(cms, resources.size() == 1 ? resources.get(0) : null);
065        } else {
066            if (m_singleResourceOnly) {
067                return CmsMenuItemVisibilityMode.VISIBILITY_INVISIBLE;
068            }
069            CmsMenuItemVisibilityMode currentVisibility = null;
070            for (CmsResource resource : resources) {
071                CmsMenuItemVisibilityMode visibilityForResource = getSingleVisibility(cms, resource);
072                if ((currentVisibility == null)
073                    || (getPriority(visibilityForResource) > getPriority(currentVisibility))) {
074                    currentVisibility = visibilityForResource;
075                }
076            }
077            if (currentVisibility == null) {
078                currentVisibility = CmsMenuItemVisibilityMode.VISIBILITY_ACTIVE;
079            }
080            if (currentVisibility.isInActive()) {
081                // In the multi-selection case, different resources may cause the menu item to be inactive for different reasons,
082                // which would make it hard to give a user-readable message. So we set the status to invisible.
083                currentVisibility = CmsMenuItemVisibilityMode.VISIBILITY_INVISIBLE;
084            }
085            return currentVisibility;
086        }
087    }
088
089    /**
090     * Gets the priority of a menu item visibility mode.<p>
091     *
092     * Higher priority modes override the ones with lower priorities.<p>
093     *
094     *
095     * @param mode the mode
096     * @return the priority for the mode
097     */
098    private int getPriority(CmsMenuItemVisibilityMode mode) {
099
100        if (mode.isPrioritized()) {
101            return 4;
102        }
103        if (mode.isInActive()) {
104            return 0;
105        }
106        if (mode.isActive()) {
107            return 1;
108        }
109        // invisible
110        return 2;
111    }
112}