    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
    018    package org.apache.logging.log4j.core.util;
    019
    020    /**
    021     * A type of Plugin builder that can be used to configure and create a plugin instance 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 plugin 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> the Plugin class this is a builder for.
    033     */
    034    public interface Builder<T> {
    035
    036        /**
    037         * Builds the plugin object after all configuration has been set. This will use default values for any
    038         * unspecified attributes for the plugin.
    039         *
    040         * @return the configured plugin instance.
    041         * @throws org.apache.logging.log4j.core.config.ConfigurationException if there was an error building the plugin
    042         * object.
    043         */
    044        T build();
    045    }