001// Copyright 2007, 2010 The Apache Software Foundation 002// 003// Licensed under the Apache License, Version 2.0 (the "License"); 004// you may not use this file except in compliance with the License. 005// You may obtain a copy of the License at 006// 007// http://www.apache.org/licenses/LICENSE-2.0 008// 009// Unless required by applicable law or agreed to in writing, software 010// distributed under the License is distributed on an "AS IS" BASIS, 011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012// See the License for the specific language governing permissions and 013// limitations under the License. 014 015package org.apache.tapestry5; 016 017import org.apache.tapestry5.services.javascript.JavaScriptSupport; 018 019/** 020 * Interface for any kind of object (typically, a component) that can provide a {@linkplain #getClientId() client-side 021 * id}, typically used in the generation of client-side (JavaScript) logic. For components, the client id will be null 022 * or inaccurate until after the component has rendered itself. Inside of any kind of loop, the clientId property is 023 * only accurate just after the component has rendered, and before it renders again. 024 * <p/> 025 * Some components must be configured to provide a client id. In many cases, the client id matches the component's 026 * {@linkplain ComponentResourcesCommon#getId() component id}, typically passed through 027 * {@link JavaScriptSupport#allocateClientId(String)} to ensure uniqueness. 028 */ 029public interface ClientElement 030{ 031 /** 032 * Returns a unique id for the element. This value will be unique for any given rendering of a page. This value is 033 * intended for use as the id attribute of the client-side element, and will be used with any DHTML/Ajax related 034 * JavaScript. 035 */ 036 String getClientId(); 037}