Example usage for java.util Random Random

Introduction

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

Prototype

public Random() 

Source Link

Document

Creates a new random number generator.

Usage

From source file:ProxyTest.java

public static void main(String[] args) {
    Object[] elements = new Object[1000];

    // fill elements with proxies for the integers 1 ... 1000
    for (int i = 0; i < elements.length; i++) {
        Integer value = i + 1;/*from ww  w. jav  a2s.  co m*/
        InvocationHandler handler = new TraceHandler(value);
        Object proxy = Proxy.newProxyInstance(null, new Class[] { Comparable.class }, handler);
        elements[i] = proxy;
    }

    // construct a random integer
    Integer key = new Random().nextInt(elements.length) + 1;

    // search for the key
    int result = Arrays.binarySearch(elements, key);

    // print match if found
    if (result >= 0)
        System.out.println(elements[result]);
}

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From source file:org.eclipse.swt.snippets.Snippet151.java

public static void main(String[] args) {
    final Display display = new Display();
    Shell shell = new Shell(display);
    shell.setText("Snippet 151");
    shell.setLayout(new FillLayout());
    final Table table = new Table(shell, SWT.BORDER | SWT.VIRTUAL);
    table.addListener(SWT.SetData, e -> {
        TableItem item = (TableItem) e.item;
        int index = table.indexOf(item);
        item.setText("Item " + data[index]);
    });//from w  w  w.j a  v  a2s . c o  m
    Thread thread = new Thread() {
        @Override
        public void run() {
            int count = 0;
            Random random = new Random();
            while (count++ < 500) {
                if (table.isDisposed())
                    return;
                // add 10 random numbers to array and sort
                int grow = 10;
                int[] newData = new int[data.length + grow];
                System.arraycopy(data, 0, newData, 0, data.length);
                int index = data.length;
                data = newData;
                for (int j = 0; j < grow; j++) {
                    data[index++] = random.nextInt();
                }
                Arrays.sort(data);
                display.syncExec(() -> {
                    if (table.isDisposed())
                        return;
                    table.setItemCount(data.length);
                    table.clearAll();
                });
                try {
                    Thread.sleep(500);
                } catch (Throwable t) {
                }
            }
        }
    };
    thread.start();
    shell.open();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

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From source file:io.druid.query.aggregation.datasketches.quantiles.GenerateTestData.java

public static void main(String[] args) throws Exception {
    Path buildPath = FileSystems.getDefault().getPath("doubles_build_data.tsv");
    Path sketchPath = FileSystems.getDefault().getPath("doubles_sketch_data.tsv");
    BufferedWriter buildData = Files.newBufferedWriter(buildPath, StandardCharsets.UTF_8);
    BufferedWriter sketchData = Files.newBufferedWriter(sketchPath, StandardCharsets.UTF_8);
    Random rand = new Random();
    int sequenceNumber = 0;
    for (int i = 0; i < 20; i++) {
        int product = rand.nextInt(10);
        UpdateDoublesSketch sketch = UpdateDoublesSketch.builder().build();
        for (int j = 0; j < 20; j++) {
            double value = rand.nextDouble();
            buildData.write("2016010101");
            buildData.write('\t');
            buildData.write(Integer.toString(sequenceNumber)); // dimension with unique numbers for ingesting raw data
            buildData.write('\t');
            buildData.write(Integer.toString(product)); // product dimension
            buildData.write('\t');
            buildData.write(Double.toString(value));
            buildData.newLine();//from w ww . j a  v a2  s . co  m
            sketch.update(value);
            sequenceNumber++;
        }
        sketchData.write("2016010101");
        sketchData.write('\t');
        sketchData.write(Integer.toString(product)); // product dimension
        sketchData.write('\t');
        sketchData.write(Base64.encodeBase64String(sketch.toByteArray(true)));
        sketchData.newLine();
    }
    buildData.close();
    sketchData.close();
}

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From source file:TableSetDataEvent.java

public static void main(String[] args) {
    final Display display = new Display();
    Shell shell = new Shell(display);
    shell.setLayout(new FillLayout());
    final Table table = new Table(shell, SWT.BORDER | SWT.VIRTUAL);
    table.addListener(SWT.SetData, new Listener() {
        public void handleEvent(Event e) {
            System.out.println(e);
            TableItem item = (TableItem) e.item;
            int index = table.indexOf(item);
            item.setText("Item " + data[index]);
        }/* w  w w  .ja  va2  s .  c om*/
    });
    int count = 0;
    Random random = new Random();
    while (count++ < 50) {
        int grow = 10;
        int[] newData = new int[data.length + grow];
        System.arraycopy(data, 0, newData, 0, data.length);
        int index = data.length;
        data = newData;
        for (int j = 0; j < grow; j++) {
            data[index++] = random.nextInt();
        }

        table.setItemCount(data.length);
        table.clearAll();
    }
    shell.open();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

---

From source file:edu.uiowa.icts.util.TopN.java

/**
 * <p>main.</p>// ww w  .jav a2 s  .  c o  m
 *
 * @param args an array of {@link java.lang.String} objects.
 */
public static void main(String args[]) {
    TopN<Double> top10 = new TopN<Double>(10);
    Random r = new Random();
    for (int i = 0; i < 10000; i++) {
        double d = r.nextDouble();
        int pos = top10.inTopN(d);
        if (pos > 0) {
            log.debug(i + ":  Rank: " + pos + " is in top 10: " + d);
        }
    }

    top10.print();
    log.debug("size: " + top10.size());
    log.debug("max: " + top10.max());

}

---

From source file:com.yahoo.ads.pb.mttf.PistachiosMTTFTest.java

public static void main(String[] args) {
    PistachiosClient client;//from  ww  w .j  a  v  a  2 s.  c  o m
    try {
        client = new PistachiosClient();
    } catch (Exception e) {
        logger.info("error creating client", e);
        return;
    }
    Random rand = new Random();

    while (true) {
        try {
            long id = rand.nextLong();
            String value = InetAddress.getLocalHost().getHostName() + rand.nextInt();
            client.store(0, id, value.getBytes());
            for (int i = 0; i < 30; i++) {
                byte[] clientValue = client.lookup(0, id);
                String remoteValue = new String(clientValue);
                if (Arrays.equals(value.getBytes(), clientValue)
                        || !remoteValue.contains(InetAddress.getLocalHost().getHostName())) {
                    logger.debug("succeeded checking id {} value {}", id, value);
                } else {
                    logger.error("failed checking id {} value {} != {}", id, value, new String(clientValue));
                    System.exit(0);
                }
                Thread.sleep(100);
            }
        } catch (Exception e) {
            System.out.println("error testing" + e);
            System.exit(0);
        }
    }
}

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From source file:org.opencredo.cloud.storage.samples.quote.S3QuoteDemo.java

public static void main(String[] args) {
    ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("quoteDemo-context.xml");

    TickerUploader tickerUploader = (TickerUploader) context.getBean("tickerUploader");
    // sending requests for tickers to be uploaded to S3, so that they can
    // later be read by another application.
    // can be commented out if already uploaded enough information
    for (int i = 0; i < 4; i++) {
        char[] chars = new char[3];
        for (int j = 0; j < 3; j++) {
            chars[j] = (char) (new Random().nextInt(25) + 65);
        }//  w ww  .ja  v a 2  s .c o  m
        String ticker = new String(chars);
        LOG.info("ticker to upload: {}", ticker);
        MessageBuilder<String> builder = MessageBuilder.withPayload(ticker);
        tickerUploader.sendTicker(builder.build());
    }
}

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From source file:apidemo.APIDemo.java

public static void main(String[] args) throws InterruptedException, Exception {
    Random random = new Random();
    int uReqFeq = 1;

    while (uReqFeq < 101) {
        String strJSON = ObjectToString(new JSMessage((long) random.nextInt(10) + 1,
                (long) random.nextInt(10) + 11, "msg_" + Integer.toString(uReqFeq)));

        String res = sendPostJson("http://localhost:9494/api/nsservice/msg", strJSON, 10000);
        System.out.println("Result: " + res);

        ++uReqFeq;/*w  ww.  ja v  a2 s.c  o m*/
    }
}

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From source file:backup.store.ExternalExtendedBlockSort.java

public static void main(String[] args) throws Exception {
    Configuration conf = new Configuration();
    Path dir = new Path("file:///home/apm/Development/git-projects/hdfs-backup/hdfs-backup-core/tmp");
    dir.getFileSystem(conf).delete(dir, true);
    long start = System.nanoTime();
    try (ExternalExtendedBlockSort<LongWritable> sort = new ExternalExtendedBlockSort<>(conf, dir,
            LongWritable.class)) {
        Random random = new Random();
        for (int bp = 0; bp < 1; bp++) {
            String bpid = UUID.randomUUID().toString();
            for (int i = 0; i < 10000000; i++) {
                // for (int i = 0; i < 10; i++) {
                long genstamp = random.nextInt(20000);
                long blockId = random.nextLong();
                ExtendedBlock extendedBlock = new ExtendedBlock(bpid, blockId,
                        random.nextInt(Integer.MAX_VALUE), genstamp);
                sort.add(extendedBlock, new LongWritable(blockId));
            }// w  w  w.  jav  a  2  s  .  c  o  m
        }
        System.out.println("finished");
        sort.finished();
        System.out.println("interate");
        for (String blockPoolId : sort.getBlockPoolIds()) {
            ExtendedBlockEnum<LongWritable> blockEnum = sort.getBlockEnum(blockPoolId);
            ExtendedBlock block;
            long l = 0;
            while ((block = blockEnum.next()) != null) {
                // System.out.println(block);
                long blockId = block.getBlockId();
                l += blockId;
                LongWritable currentValue = blockEnum.currentValue();
                if (currentValue.get() != blockId) {
                    System.err.println("Error " + blockId);
                }
            }
            System.out.println(l);
        }
    }
    long end = System.nanoTime();
    System.out.println("Time [" + (end - start) / 1000000.0 + " ms]");
}

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From source file:QuickSort.java

/**
 * @param args/*from  w  w w.  java2  s .c  om*/
 */
public static void main(String[] args) {
    Integer[] array = new Integer[15];
    Random rng = new Random();
    int split = 10;
    for (int i = 0; i < split; i++) {
        array[i] = new Integer(rng.nextInt(100));
    }
    for (int i = split; i < array.length; i++) {
        array[i] = null;
    }

    System.out.println(Arrays.toString(array));

    QuickSort.sort(array, new Comparator<Integer>() {
        @Override
        public int compare(Integer o1, Integer o2) {
            return o1.compareTo(o2);
        };
    }, 0, split - 1);

    System.out.println(Arrays.toString(array));

}

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