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 * https://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 019import java.util.function.IntUnaryOperator; 020 021/** 022 * TextRandomProvider implementations are used by {@link RandomStringGenerator} 023 * as a source of randomness. It is highly recommended that the 024 * <a href="https://commons.apache.org/proper/commons-rng/">Apache Commons RNG</a> 025 * library be used to provide the random number generation. 026 * 027 * <p> 028 * {@code TextRandomProvider} is a functional interface and need not be explicitly implemented. 029 * </p> 030 * <p> 031 * For example: 032 * </p> 033 * <pre> 034 * {@code 035 * UniformRandomProvider rng = RandomSource.create(...); 036 * RandomStringGenerator gen = RandomStringGenerator.builder() 037 * .usingRandom(rng::nextInt) 038 * // additional builder calls as needed 039 * .build(); 040 * } 041 * </pre> 042 * @since 1.1 043 */ 044public interface TextRandomProvider extends IntUnaryOperator { 045 046 /** 047 * Generates an int value between 0 (inclusive) and the specified value (exclusive). 048 * 049 * @param max Bound on the random number to be returned. Must be positive. 050 * @return a random int value between 0 (inclusive) and max (exclusive). 051 * @since 1.14.0 052 */ 053 @Override 054 default int applyAsInt(final int max) { 055 return nextInt(max); 056 } 057 058 /** 059 * Generates an int value between 0 (inclusive) and the specified value (exclusive). 060 * 061 * @param max Bound on the random number to be returned. Must be positive. 062 * @return a random int value between 0 (inclusive) and max (exclusive). 063 * @deprecated Use {@link #applyAsInt(int)}. 064 */ 065 @Deprecated 066 int nextInt(int max); 067}