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.rng.sampling.distribution;
018
019import java.util.stream.IntStream;
020
021/**
022 * Sampler that generates values of type {@code int}.
023 *
024 * @since 1.0
025 */
026@FunctionalInterface
027public interface DiscreteSampler {
028    /**
029     * Creates an {@code int} sample.
030     *
031     * @return a sample.
032     */
033    int sample();
034
035    /**
036     * Returns an effectively unlimited stream of {@code int} sample values.
037     *
038     * <p>The default implementation produces a sequential stream that repeatedly
039     * calls {@link #sample sample}().
040     *
041     * @return a stream of {@code int} values.
042     * @since 1.5
043     */
044    default IntStream samples() {
045        return IntStream.generate(this::sample).sequential();
046    }
047
048    /**
049     * Returns a stream producing the given {@code streamSize} number of {@code int}
050     * sample values.
051     *
052     * <p>The default implementation produces a sequential stream that repeatedly
053     * calls {@link #sample sample}(); the stream is limited to the given {@code streamSize}.
054     *
055     * @param streamSize Number of values to generate.
056     * @return a stream of {@code int} values.
057     * @since 1.5
058     */
059    default IntStream samples(long streamSize) {
060        return samples().limit(streamSize);
061    }
062}