util/Collection/IteratorMicroBenchmark.java

/*
 * Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @summary micro-benchmark correctness mode
 * @run main IteratorMicroBenchmark iterations=1 size=8 warmup=0
 */

import static java.util.stream.Collectors.summingInt;
import static java.util.stream.Collectors.toList;

import java.lang.ref.WeakReference;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Deque;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.PriorityQueue;
import java.util.Spliterator;
import java.util.Vector;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.LinkedTransferQueue;
import java.util.concurrent.PriorityBlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.LongAdder;
import java.util.regex.Pattern;

/**
 * Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
 *
 * To run this in micro-benchmark mode, simply run as a normal java program.
 * Be patient; this program runs for a very long time.
 * For faster runs, restrict execution using command line args.
 *
 * This is an interface based version of ArrayList/IteratorMicroBenchmark
 *
 * @author Martin Buchholz
 */
public class IteratorMicroBenchmark {
    abstract static class Job {
        private final String name;
        public Job(String name) { this.name = name; }
        public String name() { return name; }
        public abstract void work() throws Throwable;
    }

    final int iterations;
    final int size;             // number of elements in collections
    final double warmupSeconds;
    final long warmupNanos;
    final Pattern filter;       // select subset of Jobs to run
    final boolean reverse;      // reverse order of Jobs
    final boolean shuffle;      // randomize order of Jobs

    IteratorMicroBenchmark(String[] args) {
        iterations    = intArg(args, "iterations", 10_000);
        size          = intArg(args, "size", 1000);
        warmupSeconds = doubleArg(args, "warmup", 7.0);
        filter        = patternArg(args, "filter");
        reverse       = booleanArg(args, "reverse");
        shuffle       = booleanArg(args, "shuffle");

        warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
    }

    // --------------- GC finalization infrastructure ---------------

    /** No guarantees, but effective in practice. */
    static void forceFullGc() {
        CountDownLatch finalizeDone = new CountDownLatch(1);
        WeakReference<?> ref = new WeakReference<Object>(new Object() {
            protected void finalize() { finalizeDone.countDown(); }});
        try {
            for (int i = 0; i < 10; i++) {
                System.gc();
                if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
                    System.runFinalization(); // try to pick up stragglers
                    return;
                }
            }
        } catch (InterruptedException unexpected) {
            throw new AssertionError("unexpected InterruptedException");
        }
        throw new AssertionError("failed to do a \"full\" gc");
    }

    /**
     * Runs each job for long enough that all the runtime compilers
     * have had plenty of time to warm up, i.e. get around to
     * compiling everything worth compiling.
     * Returns array of average times per job per run.
     */
    long[] time0(List<Job> jobs) throws Throwable {
        final int size = jobs.size();
        long[] nanoss = new long[size];
        for (int i = 0; i < size; i++) {
            if (warmupNanos > 0) forceFullGc();
            Job job = jobs.get(i);
            long totalTime;
            int runs = 0;
            long startTime = System.nanoTime();
            do { job.work(); runs++; }
            while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
            nanoss[i] = totalTime/runs;
        }
        return nanoss;
    }

    void time(List<Job> jobs) throws Throwable {
        if (warmupNanos > 0) time0(jobs); // Warm up run
        final int size = jobs.size();
        final long[] nanoss = time0(jobs); // Real timing run
        final long[] milliss = new long[size];
        final double[] ratios = new double[size];

        final String nameHeader   = "Method";
        final String millisHeader = "Millis";
        final String ratioHeader  = "Ratio";

        int nameWidth   = nameHeader.length();
        int millisWidth = millisHeader.length();
        int ratioWidth  = ratioHeader.length();

        for (int i = 0; i < size; i++) {
            nameWidth = Math.max(nameWidth, jobs.get(i).name().length());

            milliss[i] = nanoss[i]/(1000L * 1000L);
            millisWidth = Math.max(millisWidth,
                                   String.format("%d", milliss[i]).length());

            ratios[i] = (double) nanoss[i] / (double) nanoss[0];
            ratioWidth = Math.max(ratioWidth,
                                  String.format("%.3f", ratios[i]).length());
        }

        String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
                                      nameWidth, millisWidth, ratioWidth);
        String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
                                            nameWidth, millisWidth, ratioWidth);
        System.out.printf(headerFormat, "Method", "Millis", "Ratio");

        // Print out absolute and relative times, calibrated against first job
        for (int i = 0; i < size; i++)
            System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
    }

    private static String keywordValue(String[] args, String keyword) {
        for (String arg : args)
            if (arg.startsWith(keyword))
                return arg.substring(keyword.length() + 1);
        return null;
    }

    private static int intArg(String[] args, String keyword, int defaultValue) {
        String val = keywordValue(args, keyword);
        return (val == null) ? defaultValue : Integer.parseInt(val);
    }

    private static double doubleArg(String[] args, String keyword, double defaultValue) {
        String val = keywordValue(args, keyword);
        return (val == null) ? defaultValue : Double.parseDouble(val);
    }

    private static Pattern patternArg(String[] args, String keyword) {
        String val = keywordValue(args, keyword);
        return (val == null) ? null : Pattern.compile(val);
    }

    private static boolean booleanArg(String[] args, String keyword) {
        String val = keywordValue(args, keyword);
        if (val == null || val.equals("false")) return false;
        if (val.equals("true")) return true;
        throw new IllegalArgumentException(val);
    }

    private static List<Job> filter(Pattern filter, List<Job> jobs) {
        return (filter == null) ? jobs
            : jobs.stream()
            .filter(job -> filter.matcher(job.name()).find())
            .collect(toList());
    }

    private static void deoptimize(int sum) {
        if (sum == 42)
            System.out.println("the answer");
    }

    private static <T> List<T> asSubList(List<T> list) {
        return list.subList(0, list.size());
    }

    private static <T> Iterable<T> backwards(final List<T> list) {
        return new Iterable<T>() {
            public Iterator<T> iterator() {
                return new Iterator<T>() {
                    final ListIterator<T> it = list.listIterator(list.size());
                    public boolean hasNext() { return it.hasPrevious(); }
                    public T next()          { return it.previous(); }
                    public void remove()     {        it.remove(); }};}};
    }

    // Checks for correctness *and* prevents loop optimizations
    static class Check {
        private int sum;
        public void sum(int sum) {
            if (this.sum == 0)
                this.sum = sum;
            if (this.sum != sum)
                throw new AssertionError("Sum mismatch");
        }
    }
    volatile Check check = new Check();

    public static void main(String[] args) throws Throwable {
        new IteratorMicroBenchmark(args).run();
    }

    void run() throws Throwable {
//         System.out.printf(
//             "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
//             iterations, size, warmupSeconds, filter);

        final ArrayList<Integer> al = new ArrayList<>(size);

        // Populate collections with random data
        final ThreadLocalRandom rnd = ThreadLocalRandom.current();
        for (int i = 0; i < size; i++)
            al.add(rnd.nextInt(size));

        final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
        final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
        abq.addAll(al);

        // shuffle circular array elements so they wrap
        for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
            ad.addLast(ad.removeFirst());
            abq.add(abq.remove());
        }

        ArrayList<Job> jobs = new ArrayList<>();

        List.<Collection<Integer>>of(
            al, ad, abq,
            new LinkedList<>(al),
            new PriorityQueue<>(al),
            new Vector<>(al),
            new ConcurrentLinkedQueue<>(al),
            new ConcurrentLinkedDeque<>(al),
            new LinkedBlockingQueue<>(al),
            new LinkedBlockingDeque<>(al),
            new LinkedTransferQueue<>(al),
            new PriorityBlockingQueue<>(al)).forEach(
                x -> {
                    jobs.addAll(collectionJobs(x));
                    if (x instanceof Deque)
                        jobs.addAll(dequeJobs((Deque<Integer>)x));
                });

        if (reverse) Collections.reverse(jobs);
        if (shuffle) Collections.shuffle(jobs);

        time(filter(filter, jobs));
    }

    List<Job> collectionJobs(Collection<Integer> x) {
        String klazz = x.getClass().getSimpleName();
        return List.of(
            new Job(klazz + " iterate for loop") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        int sum = 0;
                        for (Integer n : x)
                            sum += n;
                        check.sum(sum);}}},
            new Job(klazz + " iterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.iterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " spliterator().tryAdvance()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        Spliterator<Integer> spliterator = x.spliterator();
                        do {} while (spliterator.tryAdvance(n -> sum[0] += n));
                        check.sum(sum[0]);}}},
            new Job(klazz + " spliterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.spliterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " removeIf") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.removeIf(n -> { sum[0] += n; return false; }))
                            throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " contains") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    Object y = new Object() {
                        public boolean equals(Object z) {
                            sum[0] += (int) z; return false; }};
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.contains(y)) throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " remove(Object)") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    Object y = new Object() {
                        public boolean equals(Object z) {
                            sum[0] += (int) z; return false; }};
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        if (x.remove(y)) throw new AssertionError();
                        check.sum(sum[0]);}}},
            new Job(klazz + " forEach") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.forEach(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Object o : x.toArray())
                            sum[0] += (Integer) o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray(a)") {
                public void work() throws Throwable {
                    Integer[] a = new Integer[x.size()];
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.toArray(a);
                        for (Object o : a)
                            sum[0] += (Integer) o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " toArray(empty)") {
                public void work() throws Throwable {
                    Integer[] empty = new Integer[0];
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : x.toArray(empty))
                            sum[0] += o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " stream().forEach") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.stream().forEach(n -> sum[0] += n);
                        check.sum(sum[0]);}}},
            new Job(klazz + " stream().mapToInt") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.stream().mapToInt(e -> e).sum());}}},
            new Job(klazz + " stream().collect") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.stream()
                                  .collect(summingInt(e -> e)));}}},
            new Job(klazz + " stream()::iterator") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : (Iterable<Integer>) x.stream()::iterator)
                            sum[0] += o;
                        check.sum(sum[0]);}}},
            new Job(klazz + " parallelStream().forEach") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        LongAdder sum = new LongAdder();
                        x.parallelStream().forEach(n -> sum.add(n));
                        check.sum((int) sum.sum());}}},
            new Job(klazz + " parallelStream().mapToInt") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
            new Job(klazz + " parallelStream().collect") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        check.sum(x.parallelStream()
                                  .collect(summingInt(e -> e)));}}},
            new Job(klazz + " parallelStream()::iterator") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
                            sum[0] += o;
                        check.sum(sum[0]);}}});
    }

    List<Job> dequeJobs(Deque<Integer> x) {
        String klazz = x.getClass().getSimpleName();
        return List.of(
            new Job(klazz + " descendingIterator() loop") {
                public void work() throws Throwable {
                    for (int i = 0; i < iterations; i++) {
                        int sum = 0;
                        Iterator<Integer> it = x.descendingIterator();
                        while (it.hasNext())
                            sum += it.next();
                        check.sum(sum);}}},
            new Job(klazz + " descendingIterator().forEachRemaining()") {
                public void work() throws Throwable {
                    int[] sum = new int[1];
                    for (int i = 0; i < iterations; i++) {
                        sum[0] = 0;
                        x.descendingIterator().forEachRemaining(n -> sum[0] += n);
                        check.sum(sum[0]);}}});
    }
}
Revision:	1.28
Committed:	Sun Jan 7 21:05:29 2018 UTC (6 years, 4 months ago) by jsr166
Branch:	MAIN
Changes since 1.27:	+5 -6 lines
Log Message:	modernize filter methods
#	Content
1	/*
2	* Copyright (c) 2007, 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
24	/*
25	* @test
26	* @summary micro-benchmark correctness mode
27	* @run main IteratorMicroBenchmark iterations=1 size=8 warmup=0
28	*/
29
30	import static java.util.stream.Collectors.summingInt;
31	import static java.util.stream.Collectors.toList;
32
33	import java.lang.ref.WeakReference;
34	import java.util.ArrayDeque;
35	import java.util.Arrays;
36	import java.util.ArrayList;
37	import java.util.Collection;
38	import java.util.Collections;
39	import java.util.Deque;
40	import java.util.Iterator;
41	import java.util.LinkedList;
42	import java.util.List;
43	import java.util.ListIterator;
44	import java.util.PriorityQueue;
45	import java.util.Spliterator;
46	import java.util.Vector;
47	import java.util.concurrent.ArrayBlockingQueue;
48	import java.util.concurrent.ConcurrentLinkedDeque;
49	import java.util.concurrent.ConcurrentLinkedQueue;
50	import java.util.concurrent.LinkedBlockingDeque;
51	import java.util.concurrent.LinkedBlockingQueue;
52	import java.util.concurrent.LinkedTransferQueue;
53	import java.util.concurrent.PriorityBlockingQueue;
54	import java.util.concurrent.CountDownLatch;
55	import java.util.concurrent.ThreadLocalRandom;
56	import java.util.concurrent.TimeUnit;
57	import java.util.concurrent.atomic.LongAdder;
58	import java.util.regex.Pattern;
59
60	/**
61	* Usage: [iterations=N] [size=N] [filter=REGEXP] [warmup=SECONDS]
62	*
63	* To run this in micro-benchmark mode, simply run as a normal java program.
64	* Be patient; this program runs for a very long time.
65	* For faster runs, restrict execution using command line args.
66	*
67	* This is an interface based version of ArrayList/IteratorMicroBenchmark
68	*
69	* @author Martin Buchholz
70	*/
71	public class IteratorMicroBenchmark {
72	abstract static class Job {
73	private final String name;
74	public Job(String name) { this.name = name; }
75	public String name() { return name; }
76	public abstract void work() throws Throwable;
77	}
78
79	final int iterations;
80	final int size; // number of elements in collections
81	final double warmupSeconds;
82	final long warmupNanos;
83	final Pattern filter; // select subset of Jobs to run
84	final boolean reverse; // reverse order of Jobs
85	final boolean shuffle; // randomize order of Jobs
86
87	IteratorMicroBenchmark(String[] args) {
88	iterations = intArg(args, "iterations", 10_000);
89	size = intArg(args, "size", 1000);
90	warmupSeconds = doubleArg(args, "warmup", 7.0);
91	filter = patternArg(args, "filter");
92	reverse = booleanArg(args, "reverse");
93	shuffle = booleanArg(args, "shuffle");
94
95	warmupNanos = (long) (warmupSeconds * (1000L * 1000L * 1000L));
96	}
97
98	// --------------- GC finalization infrastructure ---------------
99
100	/** No guarantees, but effective in practice. */
101	static void forceFullGc() {
102	CountDownLatch finalizeDone = new CountDownLatch(1);
103	WeakReference<?> ref = new WeakReference<Object>(new Object() {
104	protected void finalize() { finalizeDone.countDown(); }});
105	try {
106	for (int i = 0; i < 10; i++) {
107	System.gc();
108	if (finalizeDone.await(1L, TimeUnit.SECONDS) && ref.get() == null) {
109	System.runFinalization(); // try to pick up stragglers
110	return;
111	}
112	}
113	} catch (InterruptedException unexpected) {
114	throw new AssertionError("unexpected InterruptedException");
115	}
116	throw new AssertionError("failed to do a \"full\" gc");
117	}
118
119	/**
120	* Runs each job for long enough that all the runtime compilers
121	* have had plenty of time to warm up, i.e. get around to
122	* compiling everything worth compiling.
123	* Returns array of average times per job per run.
124	*/
125	long[] time0(List<Job> jobs) throws Throwable {
126	final int size = jobs.size();
127	long[] nanoss = new long[size];
128	for (int i = 0; i < size; i++) {
129	if (warmupNanos > 0) forceFullGc();
130	Job job = jobs.get(i);
131	long totalTime;
132	int runs = 0;
133	long startTime = System.nanoTime();
134	do { job.work(); runs++; }
135	while ((totalTime = System.nanoTime() - startTime) < warmupNanos);
136	nanoss[i] = totalTime/runs;
137	}
138	return nanoss;
139	}
140
141	void time(List<Job> jobs) throws Throwable {
142	if (warmupNanos > 0) time0(jobs); // Warm up run
143	final int size = jobs.size();
144	final long[] nanoss = time0(jobs); // Real timing run
145	final long[] milliss = new long[size];
146	final double[] ratios = new double[size];
147
148	final String nameHeader = "Method";
149	final String millisHeader = "Millis";
150	final String ratioHeader = "Ratio";
151
152	int nameWidth = nameHeader.length();
153	int millisWidth = millisHeader.length();
154	int ratioWidth = ratioHeader.length();
155
156	for (int i = 0; i < size; i++) {
157	nameWidth = Math.max(nameWidth, jobs.get(i).name().length());
158
159	milliss[i] = nanoss[i]/(1000L * 1000L);
160	millisWidth = Math.max(millisWidth,
161	String.format("%d", milliss[i]).length());
162
163	ratios[i] = (double) nanoss[i] / (double) nanoss[0];
164	ratioWidth = Math.max(ratioWidth,
165	String.format("%.3f", ratios[i]).length());
166	}
167
168	String format = String.format("%%-%ds %%%dd %%%d.3f%%n",
169	nameWidth, millisWidth, ratioWidth);
170	String headerFormat = String.format("%%-%ds %%%ds %%%ds%%n",
171	nameWidth, millisWidth, ratioWidth);
172	System.out.printf(headerFormat, "Method", "Millis", "Ratio");
173
174	// Print out absolute and relative times, calibrated against first job
175	for (int i = 0; i < size; i++)
176	System.out.printf(format, jobs.get(i).name(), milliss[i], ratios[i]);
177	}
178
179	private static String keywordValue(String[] args, String keyword) {
180	for (String arg : args)
181	if (arg.startsWith(keyword))
182	return arg.substring(keyword.length() + 1);
183	return null;
184	}
185
186	private static int intArg(String[] args, String keyword, int defaultValue) {
187	String val = keywordValue(args, keyword);
188	return (val == null) ? defaultValue : Integer.parseInt(val);
189	}
190
191	private static double doubleArg(String[] args, String keyword, double defaultValue) {
192	String val = keywordValue(args, keyword);
193	return (val == null) ? defaultValue : Double.parseDouble(val);
194	}
195
196	private static Pattern patternArg(String[] args, String keyword) {
197	String val = keywordValue(args, keyword);
198	return (val == null) ? null : Pattern.compile(val);
199	}
200
201	private static boolean booleanArg(String[] args, String keyword) {
202	String val = keywordValue(args, keyword);
203	if (val == null \|\| val.equals("false")) return false;
204	if (val.equals("true")) return true;
205	throw new IllegalArgumentException(val);
206	}
207
208	private static List<Job> filter(Pattern filter, List<Job> jobs) {
209	return (filter == null) ? jobs
210	: jobs.stream()
211	.filter(job -> filter.matcher(job.name()).find())
212	.collect(toList());
213	}
214
215	private static void deoptimize(int sum) {
216	if (sum == 42)
217	System.out.println("the answer");
218	}
219
220	private static <T> List<T> asSubList(List<T> list) {
221	return list.subList(0, list.size());
222	}
223
224	private static <T> Iterable<T> backwards(final List<T> list) {
225	return new Iterable<T>() {
226	public Iterator<T> iterator() {
227	return new Iterator<T>() {
228	final ListIterator<T> it = list.listIterator(list.size());
229	public boolean hasNext() { return it.hasPrevious(); }
230	public T next() { return it.previous(); }
231	public void remove() { it.remove(); }};}};
232	}
233
234	// Checks for correctness and prevents loop optimizations
235	static class Check {
236	private int sum;
237	public void sum(int sum) {
238	if (this.sum == 0)
239	this.sum = sum;
240	if (this.sum != sum)
241	throw new AssertionError("Sum mismatch");
242	}
243	}
244	volatile Check check = new Check();
245
246	public static void main(String[] args) throws Throwable {
247	new IteratorMicroBenchmark(args).run();
248	}
249
250	void run() throws Throwable {
251	// System.out.printf(
252	// "iterations=%d size=%d, warmup=%1g, filter=\"%s\"%n",
253	// iterations, size, warmupSeconds, filter);
254
255	final ArrayList<Integer> al = new ArrayList<>(size);
256
257	// Populate collections with random data
258	final ThreadLocalRandom rnd = ThreadLocalRandom.current();
259	for (int i = 0; i < size; i++)
260	al.add(rnd.nextInt(size));
261
262	final ArrayDeque<Integer> ad = new ArrayDeque<>(al);
263	final ArrayBlockingQueue<Integer> abq = new ArrayBlockingQueue<>(al.size());
264	abq.addAll(al);
265
266	// shuffle circular array elements so they wrap
267	for (int i = 0, n = rnd.nextInt(size); i < n; i++) {
268	ad.addLast(ad.removeFirst());
269	abq.add(abq.remove());
270	}
271
272	ArrayList<Job> jobs = new ArrayList<>();
273
274	List.<Collection<Integer>>of(
275	al, ad, abq,
276	new LinkedList<>(al),
277	new PriorityQueue<>(al),
278	new Vector<>(al),
279	new ConcurrentLinkedQueue<>(al),
280	new ConcurrentLinkedDeque<>(al),
281	new LinkedBlockingQueue<>(al),
282	new LinkedBlockingDeque<>(al),
283	new LinkedTransferQueue<>(al),
284	new PriorityBlockingQueue<>(al)).forEach(
285	x -> {
286	jobs.addAll(collectionJobs(x));
287	if (x instanceof Deque)
288	jobs.addAll(dequeJobs((Deque<Integer>)x));
289	});
290
291	if (reverse) Collections.reverse(jobs);
292	if (shuffle) Collections.shuffle(jobs);
293
294	time(filter(filter, jobs));
295	}
296
297	List<Job> collectionJobs(Collection<Integer> x) {
298	String klazz = x.getClass().getSimpleName();
299	return List.of(
300	new Job(klazz + " iterate for loop") {
301	public void work() throws Throwable {
302	for (int i = 0; i < iterations; i++) {
303	int sum = 0;
304	for (Integer n : x)
305	sum += n;
306	check.sum(sum);}}},
307	new Job(klazz + " iterator().forEachRemaining()") {
308	public void work() throws Throwable {
309	int[] sum = new int[1];
310	for (int i = 0; i < iterations; i++) {
311	sum[0] = 0;
312	x.iterator().forEachRemaining(n -> sum[0] += n);
313	check.sum(sum[0]);}}},
314	new Job(klazz + " spliterator().tryAdvance()") {
315	public void work() throws Throwable {
316	int[] sum = new int[1];
317	for (int i = 0; i < iterations; i++) {
318	sum[0] = 0;
319	Spliterator<Integer> spliterator = x.spliterator();
320	do {} while (spliterator.tryAdvance(n -> sum[0] += n));
321	check.sum(sum[0]);}}},
322	new Job(klazz + " spliterator().forEachRemaining()") {
323	public void work() throws Throwable {
324	int[] sum = new int[1];
325	for (int i = 0; i < iterations; i++) {
326	sum[0] = 0;
327	x.spliterator().forEachRemaining(n -> sum[0] += n);
328	check.sum(sum[0]);}}},
329	new Job(klazz + " removeIf") {
330	public void work() throws Throwable {
331	int[] sum = new int[1];
332	for (int i = 0; i < iterations; i++) {
333	sum[0] = 0;
334	if (x.removeIf(n -> { sum[0] += n; return false; }))
335	throw new AssertionError();
336	check.sum(sum[0]);}}},
337	new Job(klazz + " contains") {
338	public void work() throws Throwable {
339	int[] sum = new int[1];
340	Object y = new Object() {
341	public boolean equals(Object z) {
342	sum[0] += (int) z; return false; }};
343	for (int i = 0; i < iterations; i++) {
344	sum[0] = 0;
345	if (x.contains(y)) throw new AssertionError();
346	check.sum(sum[0]);}}},
347	new Job(klazz + " remove(Object)") {
348	public void work() throws Throwable {
349	int[] sum = new int[1];
350	Object y = new Object() {
351	public boolean equals(Object z) {
352	sum[0] += (int) z; return false; }};
353	for (int i = 0; i < iterations; i++) {
354	sum[0] = 0;
355	if (x.remove(y)) throw new AssertionError();
356	check.sum(sum[0]);}}},
357	new Job(klazz + " forEach") {
358	public void work() throws Throwable {
359	int[] sum = new int[1];
360	for (int i = 0; i < iterations; i++) {
361	sum[0] = 0;
362	x.forEach(n -> sum[0] += n);
363	check.sum(sum[0]);}}},
364	new Job(klazz + " toArray()") {
365	public void work() throws Throwable {
366	int[] sum = new int[1];
367	for (int i = 0; i < iterations; i++) {
368	sum[0] = 0;
369	for (Object o : x.toArray())
370	sum[0] += (Integer) o;
371	check.sum(sum[0]);}}},
372	new Job(klazz + " toArray(a)") {
373	public void work() throws Throwable {
374	Integer[] a = new Integer[x.size()];
375	int[] sum = new int[1];
376	for (int i = 0; i < iterations; i++) {
377	sum[0] = 0;
378	x.toArray(a);
379	for (Object o : a)
380	sum[0] += (Integer) o;
381	check.sum(sum[0]);}}},
382	new Job(klazz + " toArray(empty)") {
383	public void work() throws Throwable {
384	Integer[] empty = new Integer[0];
385	int[] sum = new int[1];
386	for (int i = 0; i < iterations; i++) {
387	sum[0] = 0;
388	for (Integer o : x.toArray(empty))
389	sum[0] += o;
390	check.sum(sum[0]);}}},
391	new Job(klazz + " stream().forEach") {
392	public void work() throws Throwable {
393	int[] sum = new int[1];
394	for (int i = 0; i < iterations; i++) {
395	sum[0] = 0;
396	x.stream().forEach(n -> sum[0] += n);
397	check.sum(sum[0]);}}},
398	new Job(klazz + " stream().mapToInt") {
399	public void work() throws Throwable {
400	for (int i = 0; i < iterations; i++) {
401	check.sum(x.stream().mapToInt(e -> e).sum());}}},
402	new Job(klazz + " stream().collect") {
403	public void work() throws Throwable {
404	for (int i = 0; i < iterations; i++) {
405	check.sum(x.stream()
406	.collect(summingInt(e -> e)));}}},
407	new Job(klazz + " stream()::iterator") {
408	public void work() throws Throwable {
409	int[] sum = new int[1];
410	for (int i = 0; i < iterations; i++) {
411	sum[0] = 0;
412	for (Integer o : (Iterable<Integer>) x.stream()::iterator)
413	sum[0] += o;
414	check.sum(sum[0]);}}},
415	new Job(klazz + " parallelStream().forEach") {
416	public void work() throws Throwable {
417	for (int i = 0; i < iterations; i++) {
418	LongAdder sum = new LongAdder();
419	x.parallelStream().forEach(n -> sum.add(n));
420	check.sum((int) sum.sum());}}},
421	new Job(klazz + " parallelStream().mapToInt") {
422	public void work() throws Throwable {
423	for (int i = 0; i < iterations; i++) {
424	check.sum(x.parallelStream().mapToInt(e -> e).sum());}}},
425	new Job(klazz + " parallelStream().collect") {
426	public void work() throws Throwable {
427	for (int i = 0; i < iterations; i++) {
428	check.sum(x.parallelStream()
429	.collect(summingInt(e -> e)));}}},
430	new Job(klazz + " parallelStream()::iterator") {
431	public void work() throws Throwable {
432	int[] sum = new int[1];
433	for (int i = 0; i < iterations; i++) {
434	sum[0] = 0;
435	for (Integer o : (Iterable<Integer>) x.parallelStream()::iterator)
436	sum[0] += o;
437	check.sum(sum[0]);}}});
438	}
439
440	List<Job> dequeJobs(Deque<Integer> x) {
441	String klazz = x.getClass().getSimpleName();
442	return List.of(
443	new Job(klazz + " descendingIterator() loop") {
444	public void work() throws Throwable {
445	for (int i = 0; i < iterations; i++) {
446	int sum = 0;
447	Iterator<Integer> it = x.descendingIterator();
448	while (it.hasNext())
449	sum += it.next();
450	check.sum(sum);}}},
451	new Job(klazz + " descendingIterator().forEachRemaining()") {
452	public void work() throws Throwable {
453	int[] sum = new int[1];
454	for (int i = 0; i < iterations; i++) {
455	sum[0] = 0;
456	x.descendingIterator().forEachRemaining(n -> sum[0] += n);
457	check.sum(sum[0]);}}});
458	}
459	}