001// Copyright 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.ioc; 016 017import org.apache.tapestry5.ioc.annotations.EagerLoad; 018import org.apache.tapestry5.services.UpdateListenerHub; 019 020/** 021 * Optional interface that may be implemented by a service implementation (or even 022 * a {@linkplain ObjectLocator#proxy(Class, Class) proxy} to give the service implementation 023 * more control over its lifecyle. 024 * 025 * @since 5.2.2 026 */ 027public interface ReloadAware 028{ 029 /** 030 * Invoked when Tapestry {@linkplain UpdateListenerHub#fireCheckForUpdates() notices 031 * that the implementation class has changed}. The existing instance is notified, so that 032 * it can cleanly shutdown now, before being re-instantiated. This is necessary when the 033 * service implementation retains some form of external resources. 034 * <p> 035 * In addition, the implementation may request an immediate reload. Normally, reloading of the service is deferred 036 * until a method of the proxy object is invoked (this causes the normal just-in-time instantiation of the 037 * implementation). When this method returns true, the implementation is re-created immediately. This is most often 038 * the case for services that are {@linkplain EagerLoad eagerly loaded} in the first place. 039 * 040 * @return true if the service should be reloaded immediately, false if reload should be deferred 041 */ 042 boolean shutdownImplementationForReload(); 043}