001// Copyright 2004, 2005 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.tapestry.callback; 016 017import java.io.Serializable; 018 019import org.apache.tapestry.IRequestCycle; 020 021/** 022 * Defines a callback, an object which is used to invoke or reinvoke a method 023 * on an object or component in a later request cycle. This is used to 024 * allow certain operations (say, submitting an order) to defer to other processes 025 * (say, logging in and/or registerring). 026 * 027 * <p>Callbacks must be {@link Serializable}, to ensure that they can be stored 028 * between request cycles. 029 * 030 * @author Howard Lewis Ship 031 * @since 0.2.9 032 * 033 **/ 034 035public interface ICallback extends Serializable 036{ 037 /** 038 * Performs the call back. Typical implementation will locate a particular 039 * page or component and invoke a method upon it, or 040 * invoke a method on the {@link IRequestCycle cycle}. 041 * 042 **/ 043 044 public void performCallback(IRequestCycle cycle); 045}