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/*
* 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.lang3.builder;
/**
* 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>
* 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 3.0
*/
@FunctionalInterface
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();
}
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