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.commons.configuration2;
018
019/**
020 * <p>
021 * Definition of an interface to be implemented by {@code Configuration}
022 * implementations which support a special initialization method.
023 * </p>
024 * <p>
025 * This interface is mainly evaluated by <em>configuration builder</em>
026 * implementations: If a newly created configuration instance implements this
027 * interface, the builder calls the {@code initialize()} method. This gives
028 * {@code Configuration} classes the opportunity to perform additional
029 * initializations after all properties passed to the builder have been set.
030 * </p>
031 * <p>
032 * Another use case for this interface is to perform initializations directly
033 * which otherwise would have been done lazily. Lazy initializations can be
034 * problematic regarding thread-safety. If in contrast a configuration instance
035 * has been fully initialized when it is returned from the builder, it may be
036 * used with a {@code NoOpSynchronizer} if it is not modified.
037 * </p>
038 *
039 * @since 2.0
040 */
041public interface Initializable
042{
043    /**
044     * Initializes this object. A concrete implementation can use this method to
045     * perform arbitrary initialization. Typically, this method is invoked by a
046     * <em>configuration builder</em>. In this case, the builder's lock is held,
047     * so that all member fields set by this method are safely published.
048     */
049    void initialize();
050}