1 /*
2 * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
42 * }</pre>
43 *
44 * <p>{@code DoubleSummaryStatistics} can be used as a
45 * {@linkplain java.util.stream.Stream#collect(Collector) reduction}
46 * target for a {@linkplain java.util.stream.Stream stream}. For example:
47 *
48 * <pre> {@code
49 * DoubleSummaryStatistics stats = people.stream()
50 * .collect(Collectors.summarizingDouble(Person::getWeight));
51 *}</pre>
52 *
53 * This computes, in a single pass, the count of people, as well as the minimum,
54 * maximum, sum, and average of their weights.
55 *
56 * @implNote This implementation is not thread safe. However, it is safe to use
57 * {@link java.util.stream.Collectors#summarizingDouble(java.util.function.ToDoubleFunction)
58 * Collectors.summarizingDouble()} on a parallel stream, because the parallel
59 * implementation of {@link java.util.stream.Stream#collect Stream.collect()}
60 * provides the necessary partitioning, isolation, and merging of results for
61 * safe and efficient parallel execution.
62 * @since 1.8
63 */
64 public class DoubleSummaryStatistics implements DoubleConsumer {
65 private long count;
66 private double sum;
67 private double sumCompensation; // Low order bits of sum
68 private double simpleSum; // Used to compute right sum for non-finite inputs
69 private double min = Double.POSITIVE_INFINITY;
70 private double max = Double.NEGATIVE_INFINITY;
71
72 /**
73 * Constructs an empty instance with zero count, zero sum,
74 * {@code Double.POSITIVE_INFINITY} min, {@code Double.NEGATIVE_INFINITY}
75 * max and zero average.
76 */
77 public DoubleSummaryStatistics() { }
78
79 /**
80 * Constructs a non-empty instance with the specified {@code count},
81 * {@code min}, {@code max}, and {@code sum}.
|
1 /*
2 * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
42 * }</pre>
43 *
44 * <p>{@code DoubleSummaryStatistics} can be used as a
45 * {@linkplain java.util.stream.Stream#collect(Collector) reduction}
46 * target for a {@linkplain java.util.stream.Stream stream}. For example:
47 *
48 * <pre> {@code
49 * DoubleSummaryStatistics stats = people.stream()
50 * .collect(Collectors.summarizingDouble(Person::getWeight));
51 *}</pre>
52 *
53 * This computes, in a single pass, the count of people, as well as the minimum,
54 * maximum, sum, and average of their weights.
55 *
56 * @implNote This implementation is not thread safe. However, it is safe to use
57 * {@link java.util.stream.Collectors#summarizingDouble(java.util.function.ToDoubleFunction)
58 * Collectors.summarizingDouble()} on a parallel stream, because the parallel
59 * implementation of {@link java.util.stream.Stream#collect Stream.collect()}
60 * provides the necessary partitioning, isolation, and merging of results for
61 * safe and efficient parallel execution.
62 *
63 * <p>This implementation does not check for overflow of the count.
64 * @since 1.8
65 */
66 public class DoubleSummaryStatistics implements DoubleConsumer {
67 private long count;
68 private double sum;
69 private double sumCompensation; // Low order bits of sum
70 private double simpleSum; // Used to compute right sum for non-finite inputs
71 private double min = Double.POSITIVE_INFINITY;
72 private double max = Double.NEGATIVE_INFINITY;
73
74 /**
75 * Constructs an empty instance with zero count, zero sum,
76 * {@code Double.POSITIVE_INFINITY} min, {@code Double.NEGATIVE_INFINITY}
77 * max and zero average.
78 */
79 public DoubleSummaryStatistics() { }
80
81 /**
82 * Constructs a non-empty instance with the specified {@code count},
83 * {@code min}, {@code max}, and {@code sum}.
|