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.ui.input; 029 030import org.opencms.gwt.client.util.CmsDomUtil; 031 032import com.google.gwt.dom.client.Element; 033import com.google.gwt.dom.client.Style.Position; 034import com.google.gwt.event.dom.client.DomEvent; 035import com.google.gwt.event.shared.EventHandler; 036import com.google.gwt.event.shared.HandlerRegistration; 037import com.google.gwt.user.client.ui.Composite; 038import com.google.gwt.user.client.ui.RootPanel; 039 040/** 041 * An abstract class for widgets which represent options for select boxes.<p> 042 * 043 * @since 8.0.0 044 * 045 */ 046public abstract class A_CmsSelectCell extends Composite { 047 048 /** 049 * Measures the required width for this cell.<p> 050 * 051 * @return the required width 052 */ 053 public int getRequiredWidth() { 054 055 Element clone = CmsDomUtil.clone(getElement()); 056 clone.getStyle().setPosition(Position.ABSOLUTE); 057 RootPanel.getBodyElement().appendChild(clone); 058 int result = clone.getOffsetWidth(); 059 clone.removeFromParent(); 060 return result; 061 } 062 063 /** 064 * Returns the value of the select option as a string.<p> 065 * 066 * @return the value of the select option 067 */ 068 public abstract String getValue(); 069 070 /** 071 * Adds a new event handler to the widget.<p> 072 * 073 * This method is used because we want the select box to register some event handlers on this widget, 074 * but we can't use {@link com.google.gwt.user.client.ui.Widget#addDomHandler} directly, since it's both protected 075 * and final. 076 * 077 * @param <H> the event type 078 * @param handler the new event handler 079 * @param type the event type object 080 * 081 * @return the HandlerRegistration for removing the event handler 082 */ 083 public <H extends EventHandler> HandlerRegistration registerDomHandler(final H handler, DomEvent.Type<H> type) { 084 085 return addDomHandler(handler, type); 086 } 087 088}