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