Java tutorial
/* * This library is part of the Acacia Editor - * an open source inline and form based content editor for GWT. * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * For further information about Alkacon Software, please see the * company website: http://www.alkacon.com * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package com.alkacon.acacia.client.widgets; import com.google.gwt.dom.client.Element; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.user.client.ui.FocusWidget; /** * Abstract editing widget class.<p> */ public abstract class A_EditWidget extends FocusWidget implements I_EditWidget { /** The previous value. */ private String m_previousValue; /** * Constructor wrapping a specific DOM element.<p> * * @param element the element to wrap */ protected A_EditWidget(Element element) { super(element); m_previousValue = element.getInnerHTML(); } /** * @see com.google.gwt.event.logical.shared.HasValueChangeHandlers#addValueChangeHandler(com.google.gwt.event.logical.shared.ValueChangeHandler) */ public abstract HandlerRegistration addValueChangeHandler(ValueChangeHandler<String> handler); /** * @see com.google.gwt.user.client.ui.HasValue#getValue() */ public String getValue() { return getElement().getInnerText().trim(); } /** * @see com.alkacon.acacia.client.widgets.I_EditWidget#onAttachWidget() */ public void onAttachWidget() { super.onAttach(); } /** * @see com.alkacon.acacia.client.widgets.I_EditWidget#owns(com.google.gwt.dom.client.Element) */ public boolean owns(com.google.gwt.dom.client.Element element) { return false; } /** * Fires the value change event, if the value has changed.<p> * * @param force <code>true</code> to force firing the event, not regarding an actually changed value */ protected void fireValueChange(boolean force) { String currentValue = getValue(); if (force || !currentValue.equals(m_previousValue)) { m_previousValue = currentValue; ValueChangeEvent.fire(this, currentValue); } } /** * Returns the previous value.<p> * * @return the previous value */ protected String getPreviousValue() { return m_previousValue; } /** * Sets the previous value.<p> * * @param previousValue the previous value to set */ protected void setPreviousValue(String previousValue) { m_previousValue = previousValue; } }