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 com.google.gwt.user.client.ui.Widget; /** * Interface implemented by {@link Widget}s which can provide identifiers for at * least one element inside the component. * */ public interface SubPartAware { /** * Locates an element inside a component using the identifier provided in * {@code subPart}. The {@code subPart} identifier is component specific and * may be any string of characters, numbers, space characters and brackets. * * @param subPart * The identifier for the element inside the component * @return The element identified by subPart or null if the element could * not be found. */ com.google.gwt.user.client.Element getSubPartElement(String subPart); /** * Provides an identifier that identifies the element within the component. * The {@code subElement} is a part of the component and must never be null. * <p> * <b>Note!</b> * {@code getSubPartElement(getSubPartName(element)) == element} is <i>not * always</i> true. A component can choose to provide a more generic * identifier for any given element if the results of all interactions with * {@code subElement} are the same as interactions with the element * identified by the return value. For example a button can return an * identifier for the root element even though a DIV inside the button was * passed as {@code subElement} because interactions with the DIV and the * root button element produce the same result. * * @param subElement * The element the identifier string should uniquely identify * @return An identifier that uniquely identifies {@code subElement} or null * if no identifier could be provided. */ String getSubPartName(com.google.gwt.user.client.Element subElement); }