001 package org.apache.turbine.services;
002
003
004 /*
005 * Licensed to the Apache Software Foundation (ASF) under one
006 * or more contributor license agreements. See the NOTICE file
007 * distributed with this work for additional information
008 * regarding copyright ownership. The ASF licenses this file
009 * to you under the Apache License, Version 2.0 (the
010 * "License"); you may not use this file except in compliance
011 * with the License. You may obtain a copy of the License at
012 *
013 * http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing,
016 * software distributed under the License is distributed on an
017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018 * KIND, either express or implied. See the License for the
019 * specific language governing permissions and limitations
020 * under the License.
021 */
022
023
024 /**
025 * Classes that implement this interface need initialization before
026 * they can work.
027 *
028 * These classes rely also on an <code>InitableBroker</code> that
029 * ensures that there is only one instance of the class in the system,
030 * and handles dependencies between <code>Initables</code>.
031 *
032 * @author <a href="mailto:burton@apache.org">Kevin Burton</a>
033 * @author <a href="mailto:krzewski@e-point.pl">Rafal Krzewski</a>
034 * @version $Id: Initable.java 615328 2008-01-25 20:25:05Z tv $
035 */
036 public interface Initable
037 {
038 /**
039 * Provides an Initable with a reference to the InitableBroker
040 * that instantiated this object, so that it can access other
041 * Initables.
042 *
043 * @param broker The InitableBroker that instantiated this object.
044 */
045 void setInitableBroker(InitableBroker broker);
046
047 /**
048 * Performs early initailization of an Initable
049 *
050 * During the startup of the system, different objects may be
051 * passed to your class using this method. It should ignore any
052 * objects that it doesn't need or understand.
053 *
054 * After the class changes its internal state so that getInit()
055 * returns true, this method will be called no more, and late
056 * initialization will not be performed.
057 *
058 * If your class relies on early initialization, and the object it
059 * expects was not received, you can use late initialization to
060 * throw an exception and complain.
061 *
062 * @param data An Object to use for initialization activities.
063 * @exception InitializationException if initilaization of this
064 * class was not successful.
065 */
066 void init(Object data) throws InitializationException;
067
068 /**
069 * Performs late initialization of an Initable.
070 *
071 * When your class is being requested from an InitableBroker, it
072 * will call getInit(), and if it returns false, this method will
073 * be invoked.
074 *
075 * @exception InitializationException if initialization of this
076 * class was not successful.
077 */
078 void init() throws InitializationException;
079
080 /**
081 * Returns an <code>Initable</code> to an uninitialized state.
082 *
083 * <p>This method must release all resources allocated by the
084 * <code>Initable</code> implementation, and resetting its internal state.
085 * You may chose to implement this operation or not. If you support
086 * this operation, getInit() should return false after successful
087 * shutdown of the service.
088 */
089 void shutdown();
090
091 /**
092 * Returns initialization status of an Initable.
093 *
094 * @return Initialization status of an Initable.
095 */
096 boolean getInit();
097 }