001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.wicket;
018
019import java.util.ServiceLoader;
020
021import org.apache.wicket.request.resource.PackageResource;
022
023/**
024 * Initializes something when application loads.
025 * <p>
026 * Initializer can be used for clustering. Lets say you access a page that has a link to a resource on
027 * node A now the url for the resource gets forwarded to node B, but node B doesn't have the
028 * resource registered yet because maybe the page class hasn't been loaded and so its static block
029 * hasn't run yet. So the initializer is a place for you to register all those resources and do all
030 * the stuff you used to do in the static blocks.
031 * <p>
032 * You don't have to pre-register {@link PackageResource package resources}, as they can be
033 * initialized lazily.
034 * <p>
035 * Initializers can be configured via {@link ServiceLoader}, i.e. by having a file
036 * /META-INF/services/org.apache.wicket.IInitializer in the class path root, with each line containing the
037 * full class name of an {@link IInitializer}.
038 * </p>
039 * 
040 * @author Jonathan Locke
041 */
042public interface IInitializer
043{
044        /**
045         * @param application
046         *            The application loading the component
047         */
048        void init(Application application);
049
050
051        /**
052         * @param application
053         *            The application loading the component
054         */
055        void destroy(Application application);
056
057}