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 */
017
018package org.apache.logging.log4j.core.util;
019
020/**
021 * A type of builder that can be used to configure and create a instances using a Java DSL instead of
022 * through a configuration file. These builders are primarily useful for internal code and unit tests, but they can
023 * technically be used as a verbose alternative to configuration files.
024 *
025 * <p>
026 *     When creating <em>plugin</em> builders, it is customary to create the builder class as a public static inner class
027 *     called {@code Builder}. For instance, the builder class for
028 *     {@link org.apache.logging.log4j.core.layout.PatternLayout PatternLayout} would be
029 *     {@code PatternLayout.Builder}.
030 * </p>
031 *
032 * @param <T> This builder creates instances of this class.
033 */
034public interface Builder<T> {
035
036    /**
037     * Builds the object after all configuration has been set. This will use default values for any
038     * unspecified attributes for the object.
039     *
040     * @return the configured instance.
041     * @throws org.apache.logging.log4j.core.config.ConfigurationException if there was an error building the
042     * object.
043     */
044    T build();
045}