    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 * TextRandomProvider implementations are used by {@link RandomStringGenerator}
    021 * as a source of randomness.  It is highly recommended that the
    022 * <a href="https://commons.apache.org/proper/commons-rng/">Apache Commons RNG</a>
    023 * library be used to provide the random number generation.
    024 *
    025 * <p>
    026 * When using Java 8 or later, TextRandomProvider is a functional interface and
    027 * need not be explicitly implemented.  For example:
    028 * </p>
    029 * <pre>
    030 * {@code
    031 * UniformRandomProvider rng = RandomSource.create(...);
    032 * RandomStringGenerator gen = RandomStringGenerator.builder()
    033 *     .usingRandom(rng::nextInt)
    034 *     // additional builder calls as needed
    035 *     .build();
    036 * }
    037 * </pre>
    038 * @since 1.1
    039 */
    040public interface TextRandomProvider {
    041
    042    /**
    043     * Generates an int value between 0 (inclusive) and the specified value
    044     * (exclusive).
    045     * @param max  Bound on the random number to be returned. Must be positive.
    046     * @return a random int value between 0 (inclusive) and n (exclusive).
    047     */
    048    int nextInt(int max);
    049}