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