Example usage for java.util Random nextInt

List of usage examples for java.util Random nextInt

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Introduction

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

Prototype

public int nextInt(int bound)

Source Link

Document

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.

Usage

From source file:Main.java

public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    StyledDocument doc = new DefaultStyledDocument();
    JTextPane textPane = new JTextPane(doc);
    textPane.setText("this is a test.");

    Random random = new Random();
    for (int i = 0; i < textPane.getDocument().getLength(); i++) {
        SimpleAttributeSet set = new SimpleAttributeSet();
        StyleConstants.setForeground(set,
                new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256)));
        StyleConstants.setFontSize(set, random.nextInt(12) + 12);
        StyleConstants.setBold(set, random.nextBoolean());
        StyleConstants.setItalic(set, random.nextBoolean());
        StyleConstants.setUnderline(set, random.nextBoolean());

        doc.setCharacterAttributes(i, 1, set, true);
    }//from  w w w .j  av  a 2 s .  co  m

    frame.add(new JScrollPane(textPane));
    frame.setSize(500, 400);
    frame.setVisible(true);
}

From source file:Main.java

public static void main(String args[]) {
    JFrame frame = new JFrame("Button Sample");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    final JButton button1 = new JButton("Select Me");
    final JButton button2 = new JButton("No Select Me");
    final Random random = new Random();

    ActionListener actionListener = new ActionListener() {
        public void actionPerformed(ActionEvent actionEvent) {
            JButton button = (JButton) actionEvent.getSource();
            int red = random.nextInt(255);
            int green = random.nextInt(255);
            int blue = random.nextInt(255);
            button.setBackground(new Color(red, green, blue));
        }/*  w ww .  j a  v a2 s. c om*/
    };

    PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
        public void propertyChange(PropertyChangeEvent propertyChangeEvent) {
            String property = propertyChangeEvent.getPropertyName();
            if ("background".equals(property)) {
                button2.setBackground((Color) propertyChangeEvent.getNewValue());
            }
        }
    };

    button1.addActionListener(actionListener);
    button1.addPropertyChangeListener(propertyChangeListener);
    button2.addActionListener(actionListener);

    frame.add(button1, BorderLayout.NORTH);
    frame.add(button2, BorderLayout.SOUTH);
    frame.setSize(300, 100);
    frame.setVisible(true);
}

From source file:Main.java

public static void main(final String[] args) throws Exception {
    Random RND = new Random();
    ExecutorService es = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
    List<Future<String>> results = new ArrayList<>(10);
    for (int i = 0; i < 10; i++) {
        results.add(es.submit(new TimeSliceTask(RND.nextInt(10), TimeUnit.SECONDS)));
    }// w ww .j a  v a 2 s .  c  om
    es.shutdown();
    while (!results.isEmpty()) {
        Iterator<Future<String>> i = results.iterator();
        while (i.hasNext()) {
            Future<String> f = i.next();
            if (f.isDone()) {
                System.out.println(f.get());
                i.remove();
            }
        }
    }
}

From source file:org.eclipse.swt.snippets.Snippet375.java

public static void main(String[] args) throws Exception {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setText("Snippet 375");
    shell.setLayout(new GridLayout(1, false));

    final StringBuilder sb = new StringBuilder();
    final Random random = new Random(2546);
    for (int i = 0; i < 200; i++) {
        sb.append("Very very long text about ").append(random.nextInt(2000)).append("\t");
        if (i % 10 == 0) {
            sb.append("\n");
        }//from   w w w  .ja v  a  2  s. c  o m
    }

    // H SCROLL
    final Label lbl1 = new Label(shell, SWT.NONE);
    lbl1.setLayoutData(new GridData(GridData.BEGINNING, GridData.CENTER, true, false));
    lbl1.setText("Horizontal Scroll");

    final StyledText txt1 = new StyledText(shell, SWT.MULTI | SWT.BORDER | SWT.H_SCROLL);
    txt1.setLayoutData(new GridData(GridData.FILL, GridData.FILL, true, true));
    txt1.setText(sb.toString());
    txt1.setMouseNavigatorEnabled(true);

    // V_SCROLL
    final Label lbl2 = new Label(shell, SWT.NONE);
    lbl2.setLayoutData(new GridData(GridData.BEGINNING, GridData.CENTER, true, false));
    lbl2.setText("Vertical Scroll");

    final StyledText txt2 = new StyledText(shell, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL);
    txt2.setLayoutData(new GridData(GridData.FILL, GridData.FILL, true, true));
    txt2.setText(sb.toString());
    txt2.setMouseNavigatorEnabled(true);

    // H SCROLL & V_SCROLL
    final Label lbl3 = new Label(shell, SWT.NONE);
    lbl3.setLayoutData(new GridData(GridData.BEGINNING, GridData.CENTER, true, false));
    lbl3.setText("Horizontal and Vertical Scroll");

    final StyledText txt3 = new StyledText(shell, SWT.MULTI | SWT.BORDER | SWT.H_SCROLL | SWT.V_SCROLL);
    txt3.setLayoutData(new GridData(GridData.FILL, GridData.FILL, true, true));

    txt3.setText(sb.toString());
    txt3.setMouseNavigatorEnabled(true);

    final Button enableDisableButton = new Button(shell, SWT.PUSH);
    enableDisableButton.setLayoutData(new GridData(GridData.END, GridData.FILL, true, false));
    enableDisableButton.setText("Disable Mouse Navigation");
    enableDisableButton.addListener(SWT.Selection, e -> {
        if (txt3.getMouseNavigatorEnabled()) {
            enableDisableButton.setText("Enable Mouse Navigation");
        } else {
            enableDisableButton.setText("Disable Mouse Navigation");
        }
        txt3.setMouseNavigatorEnabled(!txt3.getMouseNavigatorEnabled());
    });

    // Disabled Scroll at start
    final Label lbl4 = new Label(shell, SWT.NONE);
    lbl4.setLayoutData(new GridData(GridData.BEGINNING, GridData.CENTER, true, false));
    lbl4.setText("No scroll at start");

    final StyledText txt4 = new StyledText(shell, SWT.MULTI | SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
    final GridData gd = new GridData(GridData.FILL, GridData.FILL, true, true);
    gd.minimumHeight = 100;
    txt4.setLayoutData(gd);

    txt4.setText("Disabled scroll");
    txt4.setMouseNavigatorEnabled(true);

    // Disabled Scroll
    final Label lbl5 = new Label(shell, SWT.NONE);
    lbl5.setLayoutData(new GridData(GridData.BEGINNING, GridData.CENTER, true, false));
    lbl5.setText("No scroll");

    final StyledText txt5 = new StyledText(shell, SWT.MULTI | SWT.BORDER);
    final GridData gd5 = new GridData(GridData.FILL, GridData.FILL, true, true);
    gd5.minimumHeight = 100;
    txt5.setLayoutData(gd5);

    txt5.setText("No scroll");
    txt5.setMouseNavigatorEnabled(true);

    shell.setSize(800, 600);
    shell.open();

    while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) {
            display.sleep();
        }
    }

    display.dispose();
}

From source file:PropertyChangeListenerDemo.java

public static void main(String args[]) {
    Runnable runner = new Runnable() {
        public void run() {
            JFrame frame = new JFrame("Button Sample");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            final JButton button1 = new JButton("Select Me");
            final JButton button2 = new JButton("No Select Me");
            final Random random = new Random();
            // Define ActionListener
            ActionListener actionListener = new ActionListener() {
                public void actionPerformed(ActionEvent actionEvent) {
                    JButton button = (JButton) actionEvent.getSource();
                    int red = random.nextInt(255);
                    int green = random.nextInt(255);
                    int blue = random.nextInt(255);
                    button.setBackground(new Color(red, green, blue));
                }//w w w  .j  a v  a  2 s .co  m
            };
            // Define PropertyChangeListener
            PropertyChangeListener propertyChangeListener = new PropertyChangeListener() {
                public void propertyChange(PropertyChangeEvent propertyChangeEvent) {
                    String property = propertyChangeEvent.getPropertyName();
                    if ("background".equals(property)) {
                        button2.setBackground((Color) propertyChangeEvent.getNewValue());
                    }
                }
            };
            button1.addActionListener(actionListener);
            button1.addPropertyChangeListener(propertyChangeListener);
            button2.addActionListener(actionListener);
            frame.add(button1, BorderLayout.NORTH);
            frame.add(button2, BorderLayout.SOUTH);
            frame.setSize(300, 100);
            frame.setVisible(true);
        }
    };
    EventQueue.invokeLater(runner);
}

From source file:dhtaccess.benchmark.LatencyMeasure.java

public static void main(String[] args) {
    boolean details = false;
    int repeats = DEFAULT_REPEATS;
    boolean doPut = true;

    // parse options
    Options options = new Options();
    options.addOption("h", "help", false, "print help");
    options.addOption("d", "details", false, "requests secret hash and TTL");
    options.addOption("r", "repeats", true, "number of requests");
    options.addOption("n", "no-put", false, "does not put");

    CommandLineParser parser = new PosixParser();
    CommandLine cmd = null;/*from w  w  w  . j  ava 2  s.  c o m*/
    try {
        cmd = parser.parse(options, args);
    } catch (ParseException e) {
        System.out.println("There is an invalid option.");
        e.printStackTrace();
        System.exit(1);
    }

    String optVal;
    if (cmd.hasOption('h')) {
        usage(COMMAND);
        System.exit(1);
    }
    if (cmd.hasOption('d')) {
        details = true;
    }
    optVal = cmd.getOptionValue('r');
    if (optVal != null) {
        repeats = Integer.parseInt(optVal);
    }
    if (cmd.hasOption('n')) {
        doPut = false;
    }

    args = cmd.getArgs();

    // parse arguments
    if (args.length < 1) {
        usage(COMMAND);
        System.exit(1);
    }

    // prepare for RPC
    int numAccessor = args.length;
    DHTAccessor[] accessorArray = new DHTAccessor[numAccessor];
    try {
        for (int i = 0; i < numAccessor; i++) {
            accessorArray[i] = new DHTAccessor(args[i]);
        }
    } catch (MalformedURLException e) {
        e.printStackTrace();
        System.exit(1);
    }

    // generate key prefix
    Random rnd = new Random(System.currentTimeMillis());

    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < KEY_PREFIX_LENGTH; i++) {
        sb.append((char) ('a' + rnd.nextInt(26)));
    }
    String keyPrefix = sb.toString();
    String valuePrefix = VALUE_PREFIX;

    // benchmarking
    System.out.println("Repeats " + repeats + " times.");

    if (doPut) {
        System.out.println("Putting: " + keyPrefix + "<number>");

        for (int i = 0; i < repeats; i++) {
            byte[] key = null, value = null;
            try {
                key = (keyPrefix + i).getBytes(ENCODE);
                value = (valuePrefix + i).getBytes(ENCODE);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
                System.exit(1);
            }

            int accIndex = rnd.nextInt(numAccessor);
            DHTAccessor acc = accessorArray[accIndex];
            acc.put(key, value, TTL);
        }
    }

    System.out.println("Benchmarking by getting.");

    int count = 0;
    long startTime = System.currentTimeMillis();

    if (details) {
        for (int i = 0; i < repeats; i++) {
            byte[] key = null;
            try {
                key = (keyPrefix + i).getBytes(ENCODE);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
                System.exit(1);
            }

            int accIndex = rnd.nextInt(numAccessor);
            DHTAccessor acc = accessorArray[accIndex];
            Set<DetailedGetResult> valueSet = acc.getDetails(key);
            if (valueSet != null && !valueSet.isEmpty()) {
                count++;
            }
        }
    } else {
        for (int i = 0; i < repeats; i++) {
            byte[] key = null;
            try {
                key = (keyPrefix + i).getBytes(ENCODE);
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
                System.exit(1);
            }

            int accIndex = rnd.nextInt(numAccessor);
            DHTAccessor acc = accessorArray[accIndex];
            Set<byte[]> valueSet = acc.get(key);
            if (valueSet != null && !valueSet.isEmpty()) {
                count++;
            }
        }
    }

    System.out.println(System.currentTimeMillis() - startTime + " msec.");
    System.out.println("Rate of successful gets: " + count + " / " + repeats);
}

From source file:com.offbynull.peernetic.debug.visualizer.App.java

public static void main(String[] args) throws Throwable {
    Random random = new Random();
    Visualizer<Integer> visualizer = new JGraphXVisualizer<>();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    Recorder<Integer> recorder = new XStreamRecorder(baos);

    visualizer.visualize(recorder, null);

    visualizer.step("Adding nodes 1 and 2", new AddNodeCommand<>(1),
            new ChangeNodeCommand(1, null, new Point(random.nextInt(400), random.nextInt(400)), Color.RED),
            new AddNodeCommand<>(2),
            new ChangeNodeCommand(2, null, new Point(random.nextInt(400), random.nextInt(400)), Color.BLUE));
    Thread.sleep(500);/*from w  ww . ja  va2 s . c  o  m*/

    visualizer.step("Adding nodes 3 and 4", new AddNodeCommand<>(3),
            new ChangeNodeCommand(3, null, new Point(random.nextInt(400), random.nextInt(400)), Color.ORANGE),
            new AddNodeCommand<>(4),
            new ChangeNodeCommand(4, null, new Point(random.nextInt(400), random.nextInt(400)), Color.PINK));
    Thread.sleep(500);

    visualizer.step("Connecting 1/2/3 to 4", new AddEdgeCommand<>(1, 4), new AddEdgeCommand<>(2, 4),
            new AddEdgeCommand<>(3, 4));
    Thread.sleep(500);

    visualizer.step("Adding trigger to 4 when no more edges",
            new TriggerOnLingeringNodeCommand(4, new RemoveNodeCommand<>(4)));
    Thread.sleep(500);

    visualizer.step("Removing connections from 1 and 2", new RemoveEdgeCommand<>(1, 4),
            new RemoveEdgeCommand<>(2, 4));
    Thread.sleep(500);

    visualizer.step("Removing connections from 3", new RemoveEdgeCommand<>(3, 4));
    Thread.sleep(500);

    recorder.close();

    Thread.sleep(2000);

    JGraphXVisualizer<Integer> visualizer2 = new JGraphXVisualizer<>();
    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
    Player<Integer> player = new XStreamPlayer<>(bais);

    visualizer2.visualize();

    player.play(visualizer2);

}

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));
            }/*from  w  w  w.  j  ava2 s.c  om*/
        }
        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]");
}

From source file:hyperloglog.tools.HyperLogLogCLI.java

public static void main(String[] args) {
    Options options = new Options();
    addOptions(options);/*from www.  j  a  va 2s .  c o  m*/

    CommandLineParser parser = new BasicParser();
    CommandLine cli = null;
    long n = 0;
    long seed = 123;
    EncodingType enc = EncodingType.SPARSE;
    int p = 14;
    int hb = 64;
    boolean bitPack = true;
    boolean noBias = true;
    int unique = -1;
    String filePath = null;
    BufferedReader br = null;
    String outFile = null;
    String inFile = null;
    FileOutputStream fos = null;
    DataOutputStream out = null;
    FileInputStream fis = null;
    DataInputStream in = null;
    try {
        cli = parser.parse(options, args);

        if (!(cli.hasOption('n') || cli.hasOption('f') || cli.hasOption('d'))) {
            System.out.println("Example usage: hll -n 1000 " + "<OR> hll -f /tmp/input.txt "
                    + "<OR> hll -d -i /tmp/out.hll");
            usage(options);
            return;
        }

        if (cli.hasOption('n')) {
            n = Long.parseLong(cli.getOptionValue('n'));
        }

        if (cli.hasOption('e')) {
            String value = cli.getOptionValue('e');
            if (value.equals(EncodingType.DENSE.name())) {
                enc = EncodingType.DENSE;
            }
        }

        if (cli.hasOption('p')) {
            p = Integer.parseInt(cli.getOptionValue('p'));
            if (p < 4 && p > 16) {
                System.out.println("Warning! Out-of-range value specified for p. Using to p=14.");
                p = 14;
            }
        }

        if (cli.hasOption('h')) {
            hb = Integer.parseInt(cli.getOptionValue('h'));
        }

        if (cli.hasOption('c')) {
            noBias = Boolean.parseBoolean(cli.getOptionValue('c'));
        }

        if (cli.hasOption('b')) {
            bitPack = Boolean.parseBoolean(cli.getOptionValue('b'));
        }

        if (cli.hasOption('f')) {
            filePath = cli.getOptionValue('f');
            br = new BufferedReader(new FileReader(new File(filePath)));
        }

        if (filePath != null && cli.hasOption('n')) {
            System.out.println("'-f' (input file) specified. Ignoring -n.");
        }

        if (cli.hasOption('s')) {
            if (cli.hasOption('o')) {
                outFile = cli.getOptionValue('o');
                fos = new FileOutputStream(new File(outFile));
                out = new DataOutputStream(fos);
            } else {
                System.err.println("Specify output file. Example usage: hll -s -o /tmp/out.hll");
                usage(options);
                return;
            }
        }

        if (cli.hasOption('d')) {
            if (cli.hasOption('i')) {
                inFile = cli.getOptionValue('i');
                fis = new FileInputStream(new File(inFile));
                in = new DataInputStream(fis);
            } else {
                System.err.println("Specify input file. Example usage: hll -d -i /tmp/in.hll");
                usage(options);
                return;
            }
        }

        // return after deserialization
        if (fis != null && in != null) {
            long start = System.currentTimeMillis();
            HyperLogLog deserializedHLL = HyperLogLogUtils.deserializeHLL(in);
            long end = System.currentTimeMillis();
            System.out.println(deserializedHLL.toString());
            System.out.println("Count after deserialization: " + deserializedHLL.count());
            System.out.println("Deserialization time: " + (end - start) + " ms");
            return;
        }

        // construct hll and serialize it if required
        HyperLogLog hll = HyperLogLog.builder().enableBitPacking(bitPack).enableNoBias(noBias).setEncoding(enc)
                .setNumHashBits(hb).setNumRegisterIndexBits(p).build();

        if (br != null) {
            Set<String> hashset = new HashSet<String>();
            String line;
            while ((line = br.readLine()) != null) {
                hll.addString(line);
                hashset.add(line);
            }
            n = hashset.size();
        } else {
            Random rand = new Random(seed);
            for (int i = 0; i < n; i++) {
                if (unique < 0) {
                    hll.addLong(rand.nextLong());
                } else {
                    int val = rand.nextInt(unique);
                    hll.addLong(val);
                }
            }
        }

        long estCount = hll.count();
        System.out.println("Actual count: " + n);
        System.out.println(hll.toString());
        System.out.println("Relative error: " + HyperLogLogUtils.getRelativeError(n, estCount) + "%");
        if (fos != null && out != null) {
            long start = System.currentTimeMillis();
            HyperLogLogUtils.serializeHLL(out, hll);
            long end = System.currentTimeMillis();
            System.out.println("Serialized hyperloglog to " + outFile);
            System.out.println("Serialized size: " + out.size() + " bytes");
            System.out.println("Serialization time: " + (end - start) + " ms");
            out.close();
        }
    } catch (ParseException e) {
        System.err.println("Invalid parameter.");
        usage(options);
    } catch (NumberFormatException e) {
        System.err.println("Invalid type for parameter.");
        usage(options);
    } catch (FileNotFoundException e) {
        System.err.println("Specified file not found.");
        usage(options);
    } catch (IOException e) {
        System.err.println("Exception occured while reading file.");
        usage(options);
    }
}

From source file:MainClass.java

public static void main(String args[]) {
    Random randomNumbers = new Random(); // random number generator

    int frequency1 = 0; // count of 1s rolled
    int frequency2 = 0; // count of 2s rolled
    int frequency3 = 0; // count of 3s rolled
    int frequency4 = 0; // count of 4s rolled
    int frequency5 = 0; // count of 5s rolled
    int frequency6 = 0; // count of 6s rolled

    int face; // stores most recently rolled value

    // summarize results of 6000 rolls of a die
    for (int roll = 1; roll <= 6000; roll++) {
        face = 1 + randomNumbers.nextInt(6); // number from 1 to 6

        // determine roll value 1-6 and increment appropriate counter
        switch (face) {
        case 1:/* w  w w.jav a2  s . co m*/
            ++frequency1; // increment the 1s counter
            break;
        case 2:
            ++frequency2; // increment the 2s counter
            break;
        case 3:
            ++frequency3; // increment the 3s counter
            break;
        case 4:
            ++frequency4; // increment the 4s counter
            break;
        case 5:
            ++frequency5; // increment the 5s counter
            break;
        case 6:
            ++frequency6; // increment the 6s counter
            break; // optional at end of switch
        }
    }

    System.out.println("Face\tFrequency"); // output headers
    System.out.printf("1\t%d\n2\t%d\n3\t%d\n4\t%d\n5\t%d\n6\t%d\n", frequency1, frequency2, frequency3,
            frequency4, frequency5, frequency6);
}