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