001/* 002 * Java Genetic Algorithm Library (jenetics-7.1.0). 003 * Copyright (c) 2007-2022 Franz Wilhelmstötter 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * 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 * Author: 018 * Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com) 019 */ 020package io.jenetics.prog.regression; 021 022import static java.util.Objects.requireNonNull; 023 024import java.lang.reflect.Array; 025import java.util.Arrays; 026import java.util.Collection; 027import java.util.List; 028import java.util.Objects; 029import java.util.function.Function; 030import java.util.stream.Stream; 031 032import io.jenetics.ext.util.Tree; 033 034import io.jenetics.prog.op.Op; 035 036/** 037 * This class holds the actual sample values which are used for the symbolic 038 * regression example. This class is <em>thread-safe</em> and can be used in a 039 * <em>producer-consumer</em> setup. You can add single sample values 040 * ({@link #add(Sample)}) or a list ({@link #addAll(Collection)}) of new values. 041 * These values will be made available for evaluation after an explicit call of 042 * the {@link #publish()} method. 043 * 044 * @implNote 045 * This class is thread-safe. 046 * 047 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a> 048 * @version 6.0 049 * @since 6.0 050 */ 051public final class SampleBuffer<T> implements Sampling<T> { 052 053 private final RingBuffer _buffer; 054 055 private volatile SampleList<T> _snapshot = null; 056 057 public SampleBuffer(final int capacity) { 058 _buffer = new RingBuffer(capacity); 059 } 060 061 /** 062 * Adding a new sample point to the buffer. <em>You need to explicitly 063 * call {@link #publish()} to make it available for the {@link #eval(Tree)} 064 * method.</em> 065 * 066 * @param sample the sample point to add 067 * @throws NullPointerException if the given {@code sample} point is 068 * {@code null} 069 */ 070 public void add(final Sample<T> sample) { 071 _buffer.add(requireNonNull(sample)); 072 } 073 074 /** 075 * The the given sample points to the buffer. <em>You need to explicitly 076 * call {@link #publish()} to make it available for the {@link #eval(Tree)} 077 * method.</em> 078 * 079 * @param samples the samples to add to the buffer 080 * @throws NullPointerException if the given {@code samples} is {@code null} 081 */ 082 public void addAll(final Collection<? extends Sample<T>> samples) { 083 samples.forEach(Objects::requireNonNull); 084 _buffer.addAll(samples); 085 } 086 087 /** 088 * Making the current sample points available for the {@link #eval(Tree)} 089 * function. 090 * 091 * @return the number of <em>published</em> sample points 092 */ 093 @SuppressWarnings({"unchecked", "rawtypes"}) 094 public int publish() { 095 final Object[] values = _buffer.snapshot(); 096 097 SampleList<T> snapshot = null; 098 if (values != null && values.length > 0) { 099 final List samples = Arrays.asList(values); 100 snapshot = new SampleList(samples); 101 } 102 103 try { 104 return snapshot != null ? snapshot.size() : 0; 105 } finally { 106 _snapshot = snapshot; 107 } 108 } 109 110 /** 111 * Return the currently <em>published</em> sample points. 112 * 113 * @see #publish() 114 * 115 * @return the currently <em>published</em> sample points 116 */ 117 List<Sample<T>> samples() { 118 final SampleList<T> snapshot = _snapshot; 119 return snapshot != null ? snapshot : List.of(); 120 } 121 122 @Override 123 public Result<T> eval(final Tree<? extends Op<T>, ?> program) { 124 requireNonNull(program); 125 126 final SampleList<T> snapshot = _snapshot; 127 return snapshot != null && !snapshot.isEmpty() 128 ? snapshot.eval(program) 129 : null; 130 } 131 132 @Override 133 public Result<T> eval(final Function<? super T[], ? extends T> function) { 134 requireNonNull(function); 135 136 final SampleList<T> snapshot = _snapshot; 137 return snapshot != null && !snapshot.isEmpty() 138 ? snapshot.eval(function) 139 : null; 140 } 141 142}