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.gwt.client.util;
029
030import com.google.gwt.user.client.ui.UIObject;
031
032/**
033 * This is a helper class for changing GWT UIObjects' styles between a set of given values.<p>
034 *
035 * Every time a new value is set, the previous value of the style variable will be removed
036 * from all associated UI objects, and the new style name will be added.
037 *
038 * @since 8.0.0
039 *
040 */
041public class CmsStyleVariable {
042
043    /** The ui objects associated with this style variable. */
044    private final UIObject[] m_uis;
045
046    /** The current style value. */
047    private String m_style;
048
049    /**
050     * Creates a new instance.<p>
051     *
052     * @param uis the list of UI objects to associate with this style variable
053     */
054    public CmsStyleVariable(UIObject... uis) {
055
056        m_uis = uis;
057    }
058
059    /**
060     * Returns the current style value.<p>
061     *
062     * @return the current style value, or <code>null</code> if non is set
063     */
064    public String getValue() {
065
066        return m_style;
067    }
068
069    /**
070     * Removes the previous value of the style variable from all associated ui objects
071     * and adds the new value as a style name to all of them.<p>
072     *
073     * @param newStyle the new style name
074     */
075    public void setValue(String newStyle) {
076
077        for (UIObject ui : m_uis) {
078            if (m_style != null) {
079                ui.removeStyleName(m_style);
080            }
081            if (newStyle != null) {
082                ui.addStyleName(newStyle);
083            }
084        }
085        m_style = newStyle;
086    }
087}