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.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.openjdk.bench.java.util.stream.tasks.IntegerDuplicate;
  24 
  25 import org.openjdk.jmh.annotations.Benchmark;
  26 import org.openjdk.jmh.annotations.BenchmarkMode;
  27 import org.openjdk.jmh.annotations.Mode;
  28 import org.openjdk.jmh.annotations.OutputTimeUnit;
  29 import org.openjdk.jmh.annotations.Scope;
  30 import org.openjdk.jmh.annotations.Setup;
  31 import org.openjdk.jmh.annotations.State;
  32 
  33 import java.util.Arrays;
  34 import java.util.Collections;
  35 import java.util.concurrent.TimeUnit;
  36 import java.util.concurrent.atomic.LongAdder;
  37 
  38 /**
  39  * This benchmark assesses flatMap() performance.
  40  */
  41 @BenchmarkMode(Mode.Throughput)
  42 @OutputTimeUnit(TimeUnit.SECONDS)
  43 @State(Scope.Thread)
  44 public class Lambda {
  45 
  46     /**
  47      * Implementation notes:
  48      *   - parallel versions need to use special sink to get the values
  49      */
  50 
  51     private IntegerDuplicateProblem problem;
  52 
  53     @Setup
  54     public void setup() {
  55         problem = new IntegerDuplicateProblem();
  56     }
  57 
  58     @Benchmark
  59     public long lambda_seq_inner() {
  60         return Arrays.stream(problem.get()).flatMap(k -> Collections.nCopies(2, k).stream())
  61                 .collect(LongAdder::new, LongAdder::add, (la1, la2) -> la1.add(la2.sum())).sum();
  62     }
  63 
  64     @Benchmark
  65     public long lambda_par_inner() {
  66         return Arrays.stream(problem.get()).parallel().flatMap(k -> Collections.nCopies(2, k).stream())
  67                 .collect(LongAdder::new, LongAdder::add, (la1, la2) -> la1.add(la2.sum())).sum();
  68     }
  69 
  70 }