1 /*
   2  * Copyright (c) 2014 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
  23  * questions.
  24  */
  25 package org.openjdk.bench.java.util.stream.ops.value;
  26 
  27 import org.openjdk.bench.java.util.stream.ops.LongAccumulator;
  28 import org.openjdk.jmh.annotations.Benchmark;
  29 import org.openjdk.jmh.annotations.BenchmarkMode;
  30 import org.openjdk.jmh.annotations.Mode;
  31 import org.openjdk.jmh.annotations.OutputTimeUnit;
  32 import org.openjdk.jmh.annotations.Param;
  33 import org.openjdk.jmh.annotations.Scope;
  34 import org.openjdk.jmh.annotations.State;
  35 
  36 import java.util.concurrent.TimeUnit;
  37 import java.util.stream.LongStream;
  38 
  39 /**
  40  * Benchmark for uniqueElements() operation.
  41  */
  42 @BenchmarkMode(Mode.Throughput)
  43 @OutputTimeUnit(TimeUnit.SECONDS)
  44 @State(Scope.Thread)
  45 public class UniqueElements {
  46 
  47     /**
  48      * Implementation notes:
  49      *   - parallel version requires thread-safe sink, we use the same for sequential version for better comparison
  50      *   - operations are explicit inner classes to untangle unwanted lambda effects
  51      *   - the result of applying consecutive operations is the same, in order to have the same number of elements in sink
  52      */
  53     @Param("100000")
  54     private int size;
  55 
  56     @Benchmark
  57     public long seq_invoke() {
  58         return LongStream.range(0, size)
  59                 .distinct()
  60                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  61     }
  62 
  63     @Benchmark
  64     public long par_invoke() {
  65         return LongStream.range(0, size).parallel()
  66                 .distinct()
  67                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  68     }
  69 
  70     @Benchmark
  71     public long seq_chain() {
  72         return LongStream.range(0, size)
  73                 .distinct()
  74                 .distinct()
  75                 .distinct()
  76                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  77     }
  78 
  79     @Benchmark
  80     public long par_chain() {
  81         return LongStream.range(0, size).parallel()
  82                 .distinct()
  83                 .distinct()
  84                 .distinct()
  85                 .collect(LongAccumulator::new, LongAccumulator::add, LongAccumulator::merge).get();
  86     }
  87 
  88 }