Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.text; /** * <p> * The Builder interface is designed to designate a class as a <em>builder</em> * object in the Builder design pattern. Builders are capable of creating and * configuring objects or results that normally take multiple steps to construct * or are very complex to derive. * </p> * * <p> * The builder interface defines a single method, {@link #build()}, that * classes must implement. The result of this method should be the final * configured object or result after all building operations are performed. * </p> * * <p> * It is a recommended practice that the methods supplied to configure the * object or result being built return a reference to {@code this} so that * method calls can be chained together. * </p> * * <p> * Example Builder: * <pre><code> * class FontBuilder implements Builder<Font> { * private Font font; * * public FontBuilder(String fontName) { * this.font = new Font(fontName, Font.PLAIN, 12); * } * * public FontBuilder bold() { * this.font = this.font.deriveFont(Font.BOLD); * return this; // Reference returned so calls can be chained * } * * public FontBuilder size(float pointSize) { * this.font = this.font.deriveFont(pointSize); * return this; // Reference returned so calls can be chained * } * * // Other Font construction methods * * public Font build() { * return this.font; * } * } * </code></pre> * * Example Builder Usage: * <pre><code> * Font bold14ptSansSerifFont = new FontBuilder(Font.SANS_SERIF).bold() * .size(14.0f) * .build(); * </code></pre> * * * @param <T> the type of object that the builder will construct or compute. * @since 1.0 * */ public interface Builder<T> { /** * Returns a reference to the object being constructed or result being * calculated by the builder. * * @return the object constructed or result calculated by the builder. */ T build(); }