Example usage for java.util Collections shuffle

Introduction

In this page you can find the example usage for java.util Collections shuffle.

Prototype

public static void shuffle(List<?> list) 

Source Link

Document

Randomly permutes the specified list using a default source of randomness.

Usage

From source file:NaturalOrderComparator.java

public static void main(String[] args) {
    String[] strings = new String[] { "1-2", "1-02", "1-20", "10-20", "fred", "jane", "pic01", "pic2", "pic02",
            "pic02a", "pic3", "pic4", "pic 4 else", "pic 5", "pic05", "pic 5", "pic 5 something", "pic 6",
            "pic   7", "pic100", "pic100a", "pic120", "pic121", "pic02000", "tom", "x2-g8", "x2-y7", "x2-y08",
            "x8-y8" };

    List orig = Arrays.asList(strings);

    System.out.println("Original: " + orig);

    List scrambled = Arrays.asList(strings);
    Collections.shuffle(scrambled);

    System.out.println("Scrambled: " + scrambled);

    Collections.sort(scrambled, new NaturalOrderComparator());

    System.out.println("Sorted: " + scrambled);
}

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From source file:Main.java

public static <V> List<V> shuffleAndSubList(List<V> list, int subSize) {
    if (list == null || list.size() == 0) {
        return null;
    }/* ww  w . j a  va 2s . c  o  m*/
    Collections.shuffle(list);
    list = list.size() > subSize ? list.subList(0, subSize) : list;
    return list;
}

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From source file:Main.java

public static String random(String src) {
    String[] srcList = src.split("");
    List<String> list = Arrays.asList(srcList);
    Collections.shuffle(list);
    StringBuilder result = new StringBuilder();
    for (String i : list) {
        result.append(i);/*from w  ww. j  av a  2 s  .c  o m*/
    }
    return result.toString();
}

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From source file:Main.java

public static void shuffleArray(int[] array) {
    List<Integer> list = new ArrayList<>();
    for (int i : array) {
        list.add(i);/*  www.  j  a  v a 2 s. co  m*/
    }

    Collections.shuffle(list);

    for (int i = 0; i < list.size(); i++) {
        array[i] = list.get(i);
    }
}

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From source file:Main.java

public static String doDraw(String cardName[], int length) {
    List<String> cardList = Arrays.asList(cardName);
    Collections.shuffle(cardList);
    return cardList.toString();
}

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From source file:Main.java

public static <K, V> List<V> selectRandom(Map<K, V> map, int size) {
    if (isNull(map)) {
        return null;
    }/*from  ww w  .j  a  va  2  s .c o m*/
    List<V> values = valueToList(map);
    if (values.size() <= size) {
        return new ArrayList<V>(values);
    }
    Collections.shuffle(values);
    return values.subList(0, size);
}

---

From source file:Main.java

public static void split(String[] items, ArrayList<String> res, int number) {
    // split items to res1 and res2, where res2 has number items
    res.clear();//from   w w  w . j  a  v a2s .c  o  m
    String res1 = "";
    String res2 = "";
    ArrayList<String> newList = new ArrayList<String>();
    for (int i = 0; i < items.length; i++) {
        newList.add(items[i]);
    }
    Collections.shuffle(newList);
    for (int i = 0; i < newList.size(); i++) {
        if (i < number) {
            res1 += newList.get(i) + "\t";
        } else {
            res2 += newList.get(i) + "\t";
        }
    }
    res.add(res1);
    res.add(res2);
}

---

From source file:Main.java

public static <T> ArrayList<T> shuffle(ArrayList<T> population, int sample) {
    ArrayList<T> newList = new ArrayList<T>();
    ArrayList<T> ret = new ArrayList<T>();
    newList.addAll(population);//from  w  ww . j  a va  2  s.c  o m

    Collections.shuffle(newList);
    ret.addAll(newList);
    for (int i = sample; i < ret.size(); i++) {
        ret.remove(i);
        i--;
    }
    newList.clear();
    return ret;
}

---

From source file:com.shirokumacafe.archetype.common.utilities.RandomData.java

/**
 * list?.
 */
public static <T> T randomOne(List<T> list) {
    Collections.shuffle(list);
    return list.get(0);
}

---

From source file:com.yahoo.pulsar.testclient.PerformanceProducer.java

public static void main(String[] args) throws Exception {
    final Arguments arguments = new Arguments();
    JCommander jc = new JCommander(arguments);
    jc.setProgramName("pulsar-perf-producer");

    try {/*from ww w. j ava 2  s. c om*/
        jc.parse(args);
    } catch (ParameterException e) {
        System.out.println(e.getMessage());
        jc.usage();
        System.exit(-1);
    }

    if (arguments.help) {
        jc.usage();
        System.exit(-1);
    }

    if (arguments.destinations.size() != 1) {
        System.out.println("Only one topic name is allowed");
        jc.usage();
        System.exit(-1);
    }

    if (arguments.confFile != null) {
        Properties prop = new Properties(System.getProperties());
        prop.load(new FileInputStream(arguments.confFile));

        if (arguments.serviceURL == null) {
            arguments.serviceURL = prop.getProperty("brokerServiceUrl");
        }

        if (arguments.serviceURL == null) {
            arguments.serviceURL = prop.getProperty("webServiceUrl");
        }

        // fallback to previous-version serviceUrl property to maintain backward-compatibility
        if (arguments.serviceURL == null) {
            arguments.serviceURL = prop.getProperty("serviceUrl", "http://localhost:8080/");
        }

        if (arguments.authPluginClassName == null) {
            arguments.authPluginClassName = prop.getProperty("authPlugin", null);
        }

        if (arguments.authParams == null) {
            arguments.authParams = prop.getProperty("authParams", null);
        }
    }

    arguments.testTime = TimeUnit.SECONDS.toMillis(arguments.testTime);

    // Dump config variables
    ObjectMapper m = new ObjectMapper();
    ObjectWriter w = m.writerWithDefaultPrettyPrinter();
    log.info("Starting Pulsar perf producer with config: {}", w.writeValueAsString(arguments));

    // Read payload data from file if needed
    byte payloadData[];
    if (arguments.payloadFilename != null) {
        payloadData = Files.readAllBytes(Paths.get(arguments.payloadFilename));
    } else {
        payloadData = new byte[arguments.msgSize];
    }

    // Now processing command line arguments
    String prefixTopicName = arguments.destinations.get(0);
    List<Future<Producer>> futures = Lists.newArrayList();

    EventLoopGroup eventLoopGroup;
    if (SystemUtils.IS_OS_LINUX) {
        eventLoopGroup = new EpollEventLoopGroup(Runtime.getRuntime().availableProcessors(),
                new DefaultThreadFactory("pulsar-perf-producer"));
    } else {
        eventLoopGroup = new NioEventLoopGroup(Runtime.getRuntime().availableProcessors(),
                new DefaultThreadFactory("pulsar-perf-producer"));
    }

    ClientConfiguration clientConf = new ClientConfiguration();
    clientConf.setConnectionsPerBroker(arguments.maxConnections);
    clientConf.setStatsInterval(arguments.statsIntervalSeconds, TimeUnit.SECONDS);
    if (isNotBlank(arguments.authPluginClassName)) {
        clientConf.setAuthentication(arguments.authPluginClassName, arguments.authParams);
    }

    PulsarClient client = new PulsarClientImpl(arguments.serviceURL, clientConf, eventLoopGroup);

    ProducerConfiguration producerConf = new ProducerConfiguration();
    producerConf.setSendTimeout(0, TimeUnit.SECONDS);
    producerConf.setCompressionType(arguments.compression);
    // enable round robin message routing if it is a partitioned topic
    producerConf.setMessageRoutingMode(MessageRoutingMode.RoundRobinPartition);
    if (arguments.batchTime > 0) {
        producerConf.setBatchingMaxPublishDelay(arguments.batchTime, TimeUnit.MILLISECONDS);
        producerConf.setBatchingEnabled(true);
        producerConf.setMaxPendingMessages(arguments.msgRate);
    }

    for (int i = 0; i < arguments.numTopics; i++) {
        String topic = (arguments.numTopics == 1) ? prefixTopicName
                : String.format("%s-%d", prefixTopicName, i);
        log.info("Adding {} publishers on destination {}", arguments.numProducers, topic);

        for (int j = 0; j < arguments.numProducers; j++) {
            futures.add(client.createProducerAsync(topic, producerConf));
        }
    }

    final List<Producer> producers = Lists.newArrayListWithCapacity(futures.size());
    for (Future<Producer> future : futures) {
        producers.add(future.get());
    }

    log.info("Created {} producers", producers.size());

    Runtime.getRuntime().addShutdownHook(new Thread() {
        public void run() {
            printAggregatedStats();
        }
    });

    Collections.shuffle(producers);
    AtomicBoolean isDone = new AtomicBoolean();

    executor.submit(() -> {
        try {
            RateLimiter rateLimiter = RateLimiter.create(arguments.msgRate);

            long startTime = System.currentTimeMillis();

            // Send messages on all topics/producers
            long totalSent = 0;
            while (true) {
                for (Producer producer : producers) {
                    if (arguments.testTime > 0) {
                        if (System.currentTimeMillis() - startTime > arguments.testTime) {
                            log.info("------------------- DONE -----------------------");
                            printAggregatedStats();
                            isDone.set(true);
                            Thread.sleep(5000);
                            System.exit(0);
                        }
                    }

                    if (arguments.numMessages > 0) {
                        if (totalSent++ >= arguments.numMessages) {
                            log.info("------------------- DONE -----------------------");
                            printAggregatedStats();
                            isDone.set(true);
                            Thread.sleep(5000);
                            System.exit(0);
                        }
                    }
                    rateLimiter.acquire();

                    final long sendTime = System.nanoTime();

                    producer.sendAsync(payloadData).thenRun(() -> {
                        messagesSent.increment();
                        bytesSent.add(payloadData.length);

                        long latencyMicros = NANOSECONDS.toMicros(System.nanoTime() - sendTime);
                        recorder.recordValue(latencyMicros);
                        cumulativeRecorder.recordValue(latencyMicros);
                    }).exceptionally(ex -> {
                        log.warn("Write error on message", ex);
                        System.exit(-1);
                        return null;
                    });
                }
            }
        } catch (Throwable t) {
            log.error("Got error", t);
        }
    });

    // Print report stats
    long oldTime = System.nanoTime();

    Histogram reportHistogram = null;

    String statsFileName = "perf-producer-" + System.currentTimeMillis() + ".hgrm";
    log.info("Dumping latency stats to {}", statsFileName);

    PrintStream histogramLog = new PrintStream(new FileOutputStream(statsFileName), false);
    HistogramLogWriter histogramLogWriter = new HistogramLogWriter(histogramLog);

    // Some log header bits
    histogramLogWriter.outputLogFormatVersion();
    histogramLogWriter.outputLegend();

    while (true) {
        try {
            Thread.sleep(10000);
        } catch (InterruptedException e) {
            break;
        }

        if (isDone.get()) {
            break;
        }

        long now = System.nanoTime();
        double elapsed = (now - oldTime) / 1e9;

        double rate = messagesSent.sumThenReset() / elapsed;
        double throughput = bytesSent.sumThenReset() / elapsed / 1024 / 1024 * 8;

        reportHistogram = recorder.getIntervalHistogram(reportHistogram);

        log.info(
                "Throughput produced: {}  msg/s --- {} Mbit/s --- Latency: mean: {} ms - med: {} - 95pct: {} - 99pct: {} - 99.9pct: {} - 99.99pct: {} - Max: {}",
                throughputFormat.format(rate), throughputFormat.format(throughput),
                dec.format(reportHistogram.getMean() / 1000.0),
                dec.format(reportHistogram.getValueAtPercentile(50) / 1000.0),
                dec.format(reportHistogram.getValueAtPercentile(95) / 1000.0),
                dec.format(reportHistogram.getValueAtPercentile(99) / 1000.0),
                dec.format(reportHistogram.getValueAtPercentile(99.9) / 1000.0),
                dec.format(reportHistogram.getValueAtPercentile(99.99) / 1000.0),
                dec.format(reportHistogram.getMaxValue() / 1000.0));

        histogramLogWriter.outputIntervalHistogram(reportHistogram);
        reportHistogram.reset();

        oldTime = now;
    }

    client.close();
}

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