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.text;
018
019/**
020 * <p>
021 * The Builder interface is designed to designate a class as a <em>builder</em>
022 * object in the Builder design pattern. Builders are capable of creating and
023 * configuring objects or results that normally take multiple steps to construct
024 * or are very complex to derive.
025 * </p>
026 *
027 * <p>
028 * The builder interface defines a single method, {@link #build()}, that
029 * classes must implement. The result of this method should be the final
030 * configured object or result after all building operations are performed.
031 * </p>
032 *
033 * <p>
034 * It is a recommended practice that the methods supplied to configure the
035 * object or result being built return a reference to {@code this} so that
036 * method calls can be chained together.
037 * </p>
038 *
039 * <p>
040 * Example Builder:
041 * </p>
042 * <pre><code>
043 * class FontBuilder implements Builder&lt;Font&gt; {
044 *     private Font font;
045 *
046 *     public FontBuilder(String fontName) {
047 *         this.font = new Font(fontName, Font.PLAIN, 12);
048 *     }
049 *
050 *     public FontBuilder bold() {
051 *         this.font = this.font.deriveFont(Font.BOLD);
052 *         return this; // Reference returned so calls can be chained
053 *     }
054 *
055 *     public FontBuilder size(float pointSize) {
056 *         this.font = this.font.deriveFont(pointSize);
057 *         return this; // Reference returned so calls can be chained
058 *     }
059 *
060 *     // Other Font construction methods
061 *
062 *     public Font build() {
063 *         return this.font;
064 *     }
065 * }
066 * </code></pre>
067 *
068 * Example Builder Usage:
069 * <pre><code>
070 * Font bold14ptSansSerifFont = new FontBuilder(Font.SANS_SERIF).bold()
071 *                                                              .size(14.0f)
072 *                                                              .build();
073 * </code></pre>
074 *
075 *
076 * @param <T> the type of object that the builder will construct or compute.
077 * @since 1.0
078 *
079 */
080public interface Builder<T> {
081
082    /**
083     * Returns a reference to the object being constructed or result being
084     * calculated by the builder.
085     *
086     * @return The object constructed or result calculated by the builder.
087     */
088    T build();
089}