Example usage for java.util Random nextBoolean

List of usage examples for java.util Random nextBoolean

  1. HOME
  2. Java
  3. java
  4. java.util.*
  5. Random
  6. nextBoolean

Introduction

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

Prototype

public boolean nextBoolean()

Source Link

Document

Returns the next pseudorandom, uniformly distributed boolean value from this random number generator's sequence.

Usage

From source file:org.apache.wicket.MarkupContainerTest.java

/**
 * Tests whether two iterators being used simultaneously keep correct score of where they are.
 *///w w  w .  j a v  a  2 s.  c  o  m
@Test
public void twoIteratorsWorkInTandem() {
    int n = NUMBER_OF_CHILDREN_FOR_A_MAP * 2;

    WebMarkupContainer wmc = new WebMarkupContainer("id");
    addNChildren(wmc, n);

    Iterator<Component> iterator1 = wmc.iterator();
    Iterator<Component> iterator2 = wmc.iterator();

    Random r = new Random();

    for (int i = 0; i < n; i++) {
        if (r.nextBoolean()) {
            iterator1.next();
            iterator1.remove();
        } else {
            iterator2.next();
            iterator2.remove();
        }
    }

    // after 2*N removals there should not be any child left
    assertThat(iterator1.hasNext(), is(false));
    assertThat(iterator2.hasNext(), is(false));
}

From source file:org.apache.wicket.MarkupContainerTest.java

/**
 * This tests a functional bug in the iterator implementation where you have multiple iterators
 * traversing the children, a detach happens and one of the iterators removes a child component
 * before the other iterator has a chance to update its internal state to the new world. This is
 * a known bug and we expect that this doesn't pose a problem in real world usage.
 *///from w w  w  . j ava 2s . c  om
@Test(expected = ConcurrentModificationException.class)
public void knownBugForDetachWithTwoIteratorsAndRemovals() {
    int n = NUMBER_OF_CHILDREN_FOR_A_MAP * 2;

    WebMarkupContainer wmc = new WebMarkupContainer("id");
    addNChildren(wmc, n);

    Iterator<Component> iterator1 = wmc.iterator();
    Iterator<Component> iterator2 = wmc.iterator();

    Random r = new Random();

    for (int i = 0; i < NUMBER_OF_CHILDREN_FOR_A_MAP; i++) {
        if (r.nextBoolean()) {
            iterator1.next();
            iterator1.remove();
        } else {
            iterator2.next();
            iterator2.remove();
        }
    }
    wmc.detach();
    iterator1.next();
    iterator1.remove();

    // implementation detail that gets in the way of properly solving this exotic use case: at
    // this moment iterator 2 doesn't know that the modification count was reset before the
    // iterator 1 removed the component.
    iterator2.next();

    // code never reaches this point due to the ConcurrentModificationException
}

From source file:org.apache.wicket.MarkupContainerTest.java

/**
 * This test is the working case for the above scenario where two iterators traverse the
 * children, the component gets detached and in this case both iterators have a chance to update
 * their internal state to the new world, before they continue to traverse the children.
 *///from   ww w  . j av  a2s.c o m
@Test
public void detachWithTwoIteratorsAndRemovalsWork() {
    int n = NUMBER_OF_CHILDREN_FOR_A_MAP * 2;

    WebMarkupContainer wmc = new WebMarkupContainer("id");
    addNChildren(wmc, n);

    Iterator<Component> iterator1 = wmc.iterator();
    Iterator<Component> iterator2 = wmc.iterator();

    Random r = new Random();

    for (int i = 0; i < NUMBER_OF_CHILDREN_FOR_A_MAP; i++) {
        Iterator<Component> iterator = r.nextBoolean() ? iterator1 : iterator2;
        if (iterator.hasNext()) {
            iterator.next();
            iterator.remove();
        }
    }
    wmc.detach();
    iterator1.next();
    iterator2.next();
    iterator1.remove();
    while (iterator1.hasNext() || iterator2.hasNext()) {
        Iterator<Component> iterator = r.nextBoolean() ? iterator1 : iterator2;
        if (iterator.hasNext()) {
            iterator.next();
            iterator.remove();
        }
    }
    assertThat(iterator1.hasNext(), is(false));
    assertThat(iterator2.hasNext(), is(false));
}

From source file:com.gatf.generator.core.GatfTestGeneratorMojo.java

private Object getPrimitiveValue(Type claz) {
    if (isPrimitive(claz)) {
        if (claz.equals(boolean.class) || claz.equals(Boolean.class)) {
            Random rand = new Random();
            return rand.nextBoolean();
        } else if (claz.equals(Date.class)) {
            return new Date();
        } else if (claz.equals(Double.class) || claz.equals(double.class)) {
            Random rand = new Random(12345678L);
            return rand.nextDouble();
        } else if (claz.equals(Float.class) || claz.equals(float.class)) {
            Random rand = new Random(12345678L);
            return rand.nextFloat();
        } else if (claz.equals(String.class)) {
            return RandomStringUtils.randomAlphabetic(10);
        } else if (claz.equals(Long.class) || claz.equals(long.class) || claz.equals(Number.class)) {
            Random rand = new Random();
            return new Long(rand.nextInt(123));
        } else if (claz.equals(Integer.class) || claz.equals(int.class)) {
            Random rand = new Random();
            return new Integer(rand.nextInt(123));
        } else if (claz.equals(BigInteger.class)) {
            Random rand = new Random();
            return new BigInteger(new BigInteger("1234567890123456789").bitLength(), rand);
        } else if (claz.equals(BigDecimal.class)) {
            Random rand = new Random();
            return new BigDecimal(rand.nextInt(123));
        } else if (claz.equals(Short.class) || claz.equals(short.class)) {
            Random rand = new Random();
            return new Short((short) rand.nextInt(123));
        }/*from w  ww .  jav  a 2 s .  c  o m*/
    }
    return null;
}

From source file:org.terracotta.offheapstore.paging.TableStealingFromStorageIT.java

@Test
@Ignore/*w ww. j  av  a  2s. co m*/
public void testSelfStealingIsStable() throws IOException {
    PageSource source = new UpfrontAllocatingPageSource(new HeapBufferSource(), MEGABYTES.toBytes(2),
            MEGABYTES.toBytes(1));

    OffHeapHashMap<Integer, byte[]> selfStealer = new WriteLockedOffHeapClockCache<>(source, true,
            new SplitStorageEngine<>(new IntegerStorageEngine(), new OffHeapBufferHalfStorageEngine<>(source,
                    KILOBYTES.toBytes(16), ByteArrayPortability.INSTANCE, false, true)));

    // failing seed value
    //long seed = 1302292028471110000L;

    long seed = System.nanoTime();
    System.err.println("Random Seed = " + seed);
    Random rndm = new Random(seed);
    int payloadSize = rndm.nextInt(KILOBYTES.toBytes(1));
    System.err.println("Payload Size = " + payloadSize);

    List<Long> sizes = new ArrayList<>();
    List<Long> tableSizes = new ArrayList<>();

    int terminalKey = 0;
    for (int key = 0; true; key++) {
        int size = selfStealer.size();
        byte[] payload = new byte[payloadSize];
        Arrays.fill(payload, (byte) key);
        selfStealer.put(key, payload);
        sizes.add((long) selfStealer.size());
        tableSizes.add(selfStealer.getTableCapacity());
        if (size >= selfStealer.size()) {
            terminalKey = key;
            selfStealer.remove(terminalKey);
            break;
        }
    }

    System.err.println("Terminal Key = " + terminalKey);

    int shrinkCount = 0;
    for (int key = terminalKey; key < 10 * terminalKey; key++) {
        byte[] payload = new byte[payloadSize];
        Arrays.fill(payload, (byte) key);
        long preTableSize = selfStealer.getTableCapacity();
        selfStealer.put(key, payload);
        if (rndm.nextBoolean()) {
            selfStealer.remove(rndm.nextInt(key));
        }
        long postTableSize = selfStealer.getTableCapacity();
        if (preTableSize > postTableSize) {
            shrinkCount++;
        }
        sizes.add((long) selfStealer.size());
        tableSizes.add(postTableSize);
    }

    if (shrinkCount != 0) {
        Map<String, List<? extends Number>> data = new HashMap<>();
        data.put("actual size", sizes);
        data.put("table size", tableSizes);

        JFreeChart chart = ChartFactory.createXYLineChart("Cache Size", "operations", "size",
                new LongListXYDataset(data), PlotOrientation.VERTICAL, true, false, false);
        File plotOutput = new File("target/TableStealingFromStorageTest.testSelfStealingIsStable.png");
        ChartUtilities.saveChartAsPNG(plotOutput, chart, 640, 480);
        fail("Expected no shrink events after reaching equilibrium : saw " + shrinkCount + " [plot in "
                + plotOutput + "]");
    }
}

From source file:com.linkedin.pinot.common.utils.DataTableBuilderTest.java

@Test
public void testSimple() throws Exception {
    final DataType[] columnTypes = DataType.values();
    final String[] columnNames = new String[columnTypes.length];

    for (int i = 0; i < columnTypes.length; i++) {
        columnNames[i] = columnTypes[i].toString();
    }//ww  w.ja  v a 2 s  . c  o  m
    final DataSchema schema = new DataSchema(columnNames, columnTypes);

    final DataTableBuilder builder = new DataTableBuilder(schema);
    builder.open();
    final Random r = new Random();
    final int NUM_ROWS = 100;

    final boolean[] boolArr = new boolean[NUM_ROWS];
    final char[] cArr = new char[NUM_ROWS];
    final byte[] bArr = new byte[NUM_ROWS];
    final short[] sArr = new short[NUM_ROWS];
    final int[] iArr = new int[NUM_ROWS];
    final float[] fArr = new float[NUM_ROWS];
    final long[] lArr = new long[NUM_ROWS];
    final double[] dArr = new double[NUM_ROWS];
    final String[] strArr = new String[NUM_ROWS];
    final Object[] oArr = new Object[NUM_ROWS];

    for (int rowId = 0; rowId < NUM_ROWS; rowId++) {
        builder.startRow();
        for (int colId = 0; colId < schema.columnNames.length; colId++) {
            final DataType type = columnTypes[colId];
            switch (type) {
            case BOOLEAN:
                final boolean bool = r.nextBoolean();
                boolArr[rowId] = bool;
                builder.setColumn(colId, bool);
                break;
            case CHAR:
                final char ch = (char) (r.nextInt(26) + 'a');
                cArr[rowId] = ch;
                builder.setColumn(colId, ch);
                break;
            case BYTE:
                final byte b = (byte) (r.nextInt((int) Math.pow(2, 8)));
                bArr[rowId] = b;
                builder.setColumn(colId, b);

                break;
            case SHORT:
                final short s = (short) (r.nextInt((int) Math.pow(2, 16)));
                sArr[rowId] = s;
                builder.setColumn(colId, s);

                break;
            case INT:
                final int i = (r.nextInt());
                iArr[rowId] = i;
                builder.setColumn(colId, i);

                break;
            case LONG:
                final long l = (r.nextLong());
                lArr[rowId] = l;
                builder.setColumn(colId, l);

                break;
            case FLOAT:
                final float f = (r.nextFloat());
                fArr[rowId] = f;
                builder.setColumn(colId, f);
                break;
            case DOUBLE:
                final double d = (r.nextDouble());
                dArr[rowId] = d;
                builder.setColumn(colId, d);
                break;
            case STRING:
                final String str = new BigInteger(130, r).toString(32);
                strArr[rowId] = str;
                builder.setColumn(colId, str);
                break;
            case OBJECT:
                final A obj = new A(r.nextInt());
                oArr[rowId] = obj;
                builder.setColumn(colId, obj);

                break;
            default:
                break;
            }
        }
        builder.finishRow();
    }
    builder.seal();
    final DataTable dataTable = builder.build();
    //System.out.println(dataTable);
    validate(dataTable, NUM_ROWS, schema, boolArr, cArr, bArr, sArr, iArr, fArr, lArr, dArr, strArr, oArr);
    final byte[] bytes = dataTable.toBytes();

    final DataTable newDataTable = new DataTable(bytes);
    validate(newDataTable, NUM_ROWS, schema, boolArr, cArr, bArr, sArr, iArr, fArr, lArr, dArr, strArr, oArr);

}

From source file:org.apache.hadoop.hive.serde2.binarysortable.TestBinarySortableFast.java

private void testBinarySortableFastCase(int caseNum, boolean doNonRandomFill, Random r,
        SerdeRandomRowSource.SupportedTypes supportedTypes, int depth) throws Throwable {

    SerdeRandomRowSource source = new SerdeRandomRowSource();

    // UNDONE: Until Fast BinarySortable supports complex types -- disable.
    source.init(r, supportedTypes, depth);

    int rowCount = 1000;
    Object[][] rows = source.randomRows(rowCount);

    if (doNonRandomFill) {
        MyTestClass.nonRandomRowFill(rows, source.primitiveCategories());
    }//from   w  ww. j  ava 2 s .co m

    // We need to operate on sorted data to fully test BinarySortable.
    source.sort(rows);

    StructObjectInspector rowStructObjectInspector = source.rowStructObjectInspector();

    TypeInfo[] typeInfos = source.typeInfos();
    int columnCount = typeInfos.length;

    int writeColumnCount = columnCount;
    StructObjectInspector writeRowStructObjectInspector = rowStructObjectInspector;
    boolean doWriteFewerColumns = r.nextBoolean();
    if (doWriteFewerColumns) {
        writeColumnCount = 1 + r.nextInt(columnCount);
        if (writeColumnCount == columnCount) {
            doWriteFewerColumns = false;
        } else {
            writeRowStructObjectInspector = source.partialRowStructObjectInspector(writeColumnCount);
        }
    }

    String fieldNames = ObjectInspectorUtils.getFieldNames(rowStructObjectInspector);
    String fieldTypes = ObjectInspectorUtils.getFieldTypes(rowStructObjectInspector);
    String order;
    order = StringUtils.leftPad("", columnCount, '+');
    String nullOrder;
    nullOrder = StringUtils.leftPad("", columnCount, 'a');
    AbstractSerDe serde_ascending = TestBinarySortableSerDe.getSerDe(fieldNames, fieldTypes, order, nullOrder);

    AbstractSerDe serde_ascending_fewer = null;
    if (doWriteFewerColumns) {
        String partialFieldNames = ObjectInspectorUtils.getFieldNames(writeRowStructObjectInspector);
        String partialFieldTypes = ObjectInspectorUtils.getFieldTypes(writeRowStructObjectInspector);

        serde_ascending_fewer = TestBinarySortableSerDe.getSerDe(partialFieldNames, partialFieldTypes, order,
                nullOrder);
    }

    order = StringUtils.leftPad("", columnCount, '-');
    nullOrder = StringUtils.leftPad("", columnCount, 'z');
    AbstractSerDe serde_descending = TestBinarySortableSerDe.getSerDe(fieldNames, fieldTypes, order, nullOrder);

    AbstractSerDe serde_descending_fewer = null;
    if (doWriteFewerColumns) {
        String partialFieldNames = ObjectInspectorUtils.getFieldNames(writeRowStructObjectInspector);
        String partialFieldTypes = ObjectInspectorUtils.getFieldTypes(writeRowStructObjectInspector);

        serde_descending_fewer = TestBinarySortableSerDe.getSerDe(partialFieldNames, partialFieldTypes, order,
                nullOrder);
    }

    boolean[] columnSortOrderIsDesc = new boolean[columnCount];
    Arrays.fill(columnSortOrderIsDesc, false);

    byte[] columnNullMarker = new byte[columnCount];
    Arrays.fill(columnNullMarker, BinarySortableSerDe.ZERO);
    byte[] columnNotNullMarker = new byte[columnCount];
    Arrays.fill(columnNotNullMarker, BinarySortableSerDe.ONE);

    /*
     * Acending.
     */
    testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
            serde_ascending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
            /* ascending */ true, typeInfos, /* useIncludeColumns */ false, /* doWriteFewerColumns */ false, r);

    testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
            serde_ascending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
            /* ascending */ true, typeInfos, /* useIncludeColumns */ true, /* doWriteFewerColumns */ false, r);

    if (doWriteFewerColumns) {
        testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
                serde_ascending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
                /* ascending */ true, typeInfos, /* useIncludeColumns */ false, /* doWriteFewerColumns */ true,
                r);

        testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
                serde_ascending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
                /* ascending */ true, typeInfos, /* useIncludeColumns */ true, /* doWriteFewerColumns */ true,
                r);
    }

    /*
     * Descending.
     */
    Arrays.fill(columnSortOrderIsDesc, true);

    testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
            serde_descending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
            /* ascending */ false, typeInfos, /* useIncludeColumns */ false, /* doWriteFewerColumns */ false,
            r);

    testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
            serde_descending, rowStructObjectInspector, serde_ascending_fewer, writeRowStructObjectInspector,
            /* ascending */ false, typeInfos, /* useIncludeColumns */ true, /* doWriteFewerColumns */ false, r);

    if (doWriteFewerColumns) {
        testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
                serde_descending, rowStructObjectInspector, serde_descending_fewer,
                writeRowStructObjectInspector, /* ascending */ false, typeInfos, /* useIncludeColumns */ false,
                /* doWriteFewerColumns */ true, r);

        testBinarySortableFast(source, rows, columnSortOrderIsDesc, columnNullMarker, columnNotNullMarker,
                serde_descending, rowStructObjectInspector, serde_descending_fewer,
                writeRowStructObjectInspector, /* ascending */ false, typeInfos, /* useIncludeColumns */ true,
                /* doWriteFewerColumns */ true, r);
    }

}

From source file:org.voltdb.TestExecutionSite.java

private void queueTransactions(long firstTxnId, int totalTransactions, Random rand) {
    for (int i = 0; i <= totalTransactions; ++i) {
        boolean rollback = rand.nextBoolean();
        // Disabling this as it results in too many all-failures currently
        //boolean rollback_all = rand.nextBoolean();
        boolean rollback_all = false;
        boolean readOnly = rand.nextBoolean();
        long txnid = i + firstTxnId;
        long safe_txnid = txnid;
        long initiator = selectRandomInitiator(rand);
        int partition = i % PARTITION_COUNT;

        int wheelOfDestiny = rand.nextInt(100);
        if (i == totalTransactions) {
            testLog.info("Queueing final heartbeat.");
            int offset = 0;
            for (long inid : getInitiatorIds()) {
                createHeartBeat(txnid + offset, txnid + offset, inid);
                ++offset;/* w w  w . j  a v a2  s  .co m*/
            }
        } else if (wheelOfDestiny < 50) {
            createSPInitiation(readOnly, txnid, safe_txnid, initiator, partition);
        } else if (wheelOfDestiny < 70) {
            int numberOfBatches = rand.nextInt(4) + 1;
            List<Long> participants = new ArrayList<Long>();
            long coordinator = selectCoordinatorAndParticipants(rand, partition, initiator, participants);
            createMPInitiation(rollback, rollback_all, readOnly, numberOfBatches, txnid, safe_txnid, initiator,
                    partition, coordinator, participants);
        } else {
            createHeartBeat(txnid, safe_txnid, initiator);
        }
    }
}

From source file:uk.ac.imperial.presage2.web.export.TestDataExport.java

@Test
public void testTransientAgentPropertyWithCondition() throws JSONException {
    Random rand = new Random();

    // prepare test data
    logger.info("Creating conditioned TransientAgentProperty test data set");
    int simCount = rand.nextInt(9) + 1;
    long[] simIds = new long[simCount];

    // expectations of test data.
    int[] expectedCount1 = new int[100];
    int[] expectedCount2 = new int[100];
    Arrays.fill(expectedCount2, 0);
    int[] expectedCount3 = new int[100];
    Arrays.fill(expectedCount3, 0);

    for (int s = 0; s < simCount; s++) {
        int finishAt = 1 + rand.nextInt(99);
        int agentCount = 1 + rand.nextInt(20);
        PersistentSimulation sim = sto.createSimulation("Test", "test", "TEST", finishAt);
        sto.setSimulation(sim);// ww w  .j  a  va  2 s.  c  o  m
        sim.setCurrentTime(finishAt);
        Set<PersistentAgent> agents = new HashSet<PersistentAgent>();
        for (int a = 0; a < agentCount; a++) {
            PersistentAgent ag = sto.createAgent(uk.ac.imperial.presage2.core.util.random.Random.randomUUID(),
                    "agent" + a);
            agents.add(ag);
            boolean test = rand.nextBoolean();
            ag.setProperty("testA", Boolean.toString(test));
            if (test) {
                for (int j = 0; j < finishAt; j++) {
                    expectedCount1[j]++;
                }
            }
        }
        for (int i = 0; i < finishAt; i++) {
            for (PersistentAgent a : agents) {
                int datapoint = rand.nextInt(100);

                a.getState(i).setProperty("test", Integer.toString(datapoint));
                if (datapoint > 50)
                    expectedCount2[i]++;
                if (datapoint <= 75 && a.getProperty("testA").equalsIgnoreCase("true"))
                    expectedCount3[i]++;
            }
        }
        simIds[s] = sim.getID();
        logger.info("Sim " + sim.getID() + ", " + finishAt + " steps, " + agentCount + " agents.");
    }

    // prepare input JSON
    JSONObject inputJson = new JSONObject();
    inputJson.put("sources", new JSONArray(simIds));
    inputJson.put("parameters", new JSONArray(new String[] { "time" }));

    JSONObject test1 = new JSONObject();
    test1.put("type", "AGENT");
    test1.put("property", "test");
    test1.put("function", "COUNT");
    JSONObject test1Condition = new JSONObject();
    test1Condition.put("testA", true);
    test1.put("condition", test1Condition);

    JSONObject test2 = new JSONObject();
    test2.put("type", "AGENT");
    test2.put("property", "test");
    test2.put("function", "COUNT");
    JSONObject test2Condition = new JSONObject("{\"$t\":{\"test\":{\"$gt\":50}}}");
    test2.put("condition", test2Condition);

    JSONObject test3 = new JSONObject();
    test3.put("type", "AGENT");
    test3.put("property", "test");
    test3.put("function", "COUNT");
    JSONObject test3Condition = new JSONObject();
    test3Condition.put("testA", true);
    test3Condition.put("$t", new JSONObject("{\"test\":{\"$lte\":75}}"));
    test3.put("condition", test3Condition);

    inputJson.put("columns", new JSONArray(new JSONObject[] { test1, test2, test3 }));

    logger.info("Test json input: " + inputJson.toString());

    // test servlet
    Iterable<Iterable<String>> actual = servletUnderTest.processRequest(inputJson);

    // check expectations
    int row = -1;
    int col = 0;
    for (Iterable<String> iterable : actual) {
        logger.info("Test results row: " + row);
        for (String string : iterable) {
            if (row == -1) {
                switch (col) {
                case 0:
                    assertEquals("timestep", string);
                    break;
                }
            } else {
                switch (col) {
                // timestep col
                case 0:
                    assertEquals(row, Integer.parseInt(string));
                    break;
                // min col
                case 1:
                    assertEquals(expectedCount1[row], Integer.parseInt(string));
                    break;
                // max col
                case 2:
                    assertEquals(expectedCount2[row], Integer.parseInt(string));
                    break;
                // mean col
                case 3:
                    assertEquals(expectedCount3[row], Integer.parseInt(string));
                    break;
                }
            }
            col++;
        }
        col = 0;
        row++;
    }
}

From source file:com.pivotal.gemfire.tools.pulse.testbed.PropMockDataUpdater.java

private void refresh(Member m) {
    if (LOGGER.infoEnabled()) {
        LOGGER.info(resourceBundle.getString("LOG_MSG_REFRESHING_MEMBER_DATA") + " : " + m.getName());
    }/*from w  ww .  j a va 2 s. c om*/

    Random r = new Random(System.currentTimeMillis());

    m.setUptime(System.currentTimeMillis());
    m.setQueueBacklog("" + Math.abs(r.nextInt(500)));
    m.setCurrentHeapSize(Math.abs(r.nextInt(Math.abs((int) m.getMaxHeapSize()))));
    m.setTotalDiskUsage(Math.abs(r.nextInt(100)));

    Float cpuUsage = r.nextFloat() * 100;
    m.getCpuUsageSamples().add(cpuUsage);
    m.setCpuUsage(cpuUsage);

    m.getHeapUsageSamples().add(m.getCurrentHeapSize());
    m.setLoadAverage((double) Math.abs(r.nextInt(100)));
    m.setNumThreads(Math.abs(r.nextInt(100)));
    m.setGarbageCollectionCount((long) Math.abs(r.nextInt(100)));
    m.getGarbageCollectionSamples().add(m.getGarbageCollectionCount());

    m.setTotalFileDescriptorOpen((long) Math.abs(r.nextInt(100)));

    m.setThroughputWrites(Math.abs(r.nextInt(10)));
    m.getThroughputWritesTrend().add(m.getThroughputWrites());

    m.setGetsRate(Math.abs(r.nextInt(5000)));
    m.getGetsPerSecond().add(m.getGetsRate());

    m.setPutsRate(Math.abs(r.nextInt(5000)));
    m.getPutsPerSecond().add(m.getPutsRate());

    Alert[] alerts = cluster.getAlertsList();
    List<Alert> alertsList = new ArrayList<Alert>(Arrays.asList(alerts));

    if (r.nextBoolean()) {
        // Generate alerts
        if (r.nextBoolean()) {
            if (r.nextInt(10) > 5) {
                alertsList.add(createAlert(Alert.SEVERE, m.getName(), alertsList.size()));
                if (alertsList.size() > ALERTS_MAX_SIZE) {
                    alertsList.remove(0);
                }
            }
        }

        if (r.nextBoolean()) {
            if (r.nextInt(10) > 5) {
                alertsList.add(createAlert(Alert.ERROR, m.getName(), alertsList.size()));
                if (alertsList.size() > ALERTS_MAX_SIZE) {
                    alertsList.remove(0);
                }
            }
        }

        if (r.nextBoolean()) {
            if (r.nextInt(10) > 5) {
                alertsList.add(createAlert(Alert.WARNING, m.getName(), alertsList.size()));
                if (alertsList.size() > ALERTS_MAX_SIZE) {
                    alertsList.remove(0);
                }
            }
        }
    }
}