Java tutorial
/* * Copyright 2000-2018 Vaadin Ltd. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package com.vaadin.client.ui; import java.util.List; import com.google.gwt.user.client.ui.Widget; import com.vaadin.client.ComponentConnector; /** * Client side connector for subclasses of AbstractSingleComponentConnector. * * @since 7.0 */ public abstract class AbstractSingleComponentContainerConnector extends AbstractHasComponentsConnector { /** * Returns the content (only/first child) of the container. * * @return child connector or null if none (e.g. invisible or not set on * server) */ protected ComponentConnector getContent() { List<ComponentConnector> children = getChildComponents(); if (children.isEmpty()) { return null; } else { return children.get(0); } } /** * Returns the widget (if any) of the content of the container. * * @return widget of the only/first connector of the container, null if no * content or if there is no widget for the connector */ protected Widget getContentWidget() { ComponentConnector content = getContent(); if (null != content) { return content.getWidget(); } else { return null; } } }