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 */ 017 018package org.apache.commons.rng.sampling; 019 020import java.util.stream.Stream; 021 022/** 023 * Sampler that generates values of a specified type. 024 * 025 * @param <T> Type of the sample. 026 * @since 1.4 027 */ 028public interface ObjectSampler<T> { 029 /** 030 * Create an object sample. 031 * 032 * @return a sample. 033 */ 034 T sample(); 035 036 /** 037 * Returns an effectively unlimited stream of object sample values. 038 * 039 * <p>The default implementation produces a sequential stream that repeatedly 040 * calls {@link #sample sample}(). 041 * 042 * @return a stream of object values. 043 * @since 1.5 044 */ 045 default Stream<T> samples() { 046 return Stream.generate(this::sample).sequential(); 047 } 048 049 /** 050 * Returns a stream producing the given {@code streamSize} number of object 051 * sample values. 052 * 053 * <p>The default implementation produces a sequential stream that repeatedly 054 * calls {@link #sample sample}(); the stream is limited to the given {@code streamSize}. 055 * 056 * @param streamSize Number of values to generate. 057 * @return a stream of object values. 058 * @since 1.5 059 */ 060 default Stream<T> samples(long streamSize) { 061 return samples().limit(streamSize); 062 } 063}