Example usage for java.util Random nextBytes

Introduction

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

Prototype

public void nextBytes(byte[] bytes) 

Source Link

Document

Generates random bytes and places them into a user-supplied byte array.

Usage

From source file:com.opengamma.engine.cache.BerkeleyDBValueSpecificationIdentifierBinaryDataStoreTest.java

public void getPerformanceTest() {
    final int numEntries = 500;
    final int numCycles = 5;
    final int numGets = numCycles * numEntries;
    final int minEntrySize = 50;
    final int maxEntrySize = 1000;
    final Random random = new Random();

    File dbDir = createDbDir("getPerformanceTest");
    Environment dbEnvironment = BerkeleyDBViewComputationCacheSource.constructDatabaseEnvironment(dbDir, false);

    BerkeleyDBBinaryDataStore dataStore = new BerkeleyDBBinaryDataStore(dbEnvironment, "getPerformanceTest");
    dataStore.start();//from   w  w  w.j ava  2  s  . c o  m

    int randRange = maxEntrySize - minEntrySize;
    for (int i = 0; i < numEntries; i++) {
        int nBytes = minEntrySize + random.nextInt(randRange);
        byte[] bytes = new byte[nBytes];
        random.nextBytes(bytes);
        dataStore.put(i, bytes);
    }

    OperationTimer timer = new OperationTimer(s_logger, "Loading {} entries", numGets);
    for (int j = 0; j < numCycles; j++) {
        for (int i = 0; i < numEntries; i++) {
            byte[] data = dataStore.get(i);
            assertNotNull(data);
            assertTrue(data.length >= minEntrySize);
            assertTrue(data.length <= maxEntrySize);
        }
    }

    long numMillis = timer.finished();

    double msPerGet = ((double) numMillis) / ((double) numGets);
    double getsPerSecond = 1000.0 / msPerGet;

    s_logger.info("for {} gets, {} ms/get, {} gets/sec", new Object[] { numGets, msPerGet, getsPerSecond });

    dataStore.delete();
    dataStore.stop();
    dbEnvironment.close();
}

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From source file:org.apache.hadoop.mapred.TestSequenceFileInputFormat.java

public void testFormat() throws Exception {
    JobConf job = new JobConf(conf);
    FileSystem fs = FileSystem.getLocal(conf);
    Path dir = new Path(System.getProperty("test.build.data", ".") + "/mapred");
    Path file = new Path(dir, "test.seq");

    Reporter reporter = Reporter.NULL;/*  w w  w  .  ja  va  2s  .c  om*/

    int seed = new Random().nextInt();
    //LOG.info("seed = "+seed);
    Random random = new Random(seed);

    fs.delete(dir, true);

    FileInputFormat.setInputPaths(job, dir);

    // for a variety of lengths
    for (int length = 0; length < MAX_LENGTH; length += random.nextInt(MAX_LENGTH / 10) + 1) {

        //LOG.info("creating; entries = " + length);

        // create a file with length entries
        SequenceFile.Writer writer = SequenceFile.createWriter(fs, conf, file, IntWritable.class,
                BytesWritable.class);
        try {
            for (int i = 0; i < length; i++) {
                IntWritable key = new IntWritable(i);
                byte[] data = new byte[random.nextInt(10)];
                random.nextBytes(data);
                BytesWritable value = new BytesWritable(data);
                writer.append(key, value);
            }
        } finally {
            writer.close();
        }

        // try splitting the file in a variety of sizes
        InputFormat<IntWritable, BytesWritable> format = new SequenceFileInputFormat<IntWritable, BytesWritable>();
        IntWritable key = new IntWritable();
        BytesWritable value = new BytesWritable();
        for (int i = 0; i < 3; i++) {
            int numSplits = random.nextInt(MAX_LENGTH / (SequenceFile.SYNC_INTERVAL / 20)) + 1;
            //LOG.info("splitting: requesting = " + numSplits);
            InputSplit[] splits = format.getSplits(job, numSplits);
            //LOG.info("splitting: got =        " + splits.length);

            // check each split
            BitSet bits = new BitSet(length);
            for (int j = 0; j < splits.length; j++) {
                RecordReader<IntWritable, BytesWritable> reader = format.getRecordReader(splits[j], job,
                        reporter);
                try {
                    int count = 0;
                    while (reader.next(key, value)) {
                        // if (bits.get(key.get())) {
                        // LOG.info("splits["+j+"]="+splits[j]+" : " + key.get());
                        // LOG.info("@"+reader.getPos());
                        // }
                        assertFalse("Key in multiple partitions.", bits.get(key.get()));
                        bits.set(key.get());
                        count++;
                    }
                    //LOG.info("splits["+j+"]="+splits[j]+" count=" + count);
                } finally {
                    reader.close();
                }
            }
            assertEquals("Some keys in no partition.", length, bits.cardinality());
        }

    }
}

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From source file:com.emc.ecs.sync.CasMigrationTest.java

@Test
public void testPipedStreams() throws Exception {
    Random random = new Random();

    // test smaller than pipe buffer
    byte[] source = new byte[random.nextInt(BUFFER_SIZE) + 1];
    random.nextBytes(source);
    String md5 = Hex.encodeHexString(MessageDigest.getInstance("MD5").digest(source));
    Assert.assertEquals("MD5 mismatch", md5, pipeAndGetMd5(source));

    // test larger than pipe buffer
    source = new byte[random.nextInt(BUFFER_SIZE) + BUFFER_SIZE + 1];
    random.nextBytes(source);/*from  w  w  w .  java2s.c om*/
    md5 = Hex.encodeHexString(MessageDigest.getInstance("MD5").digest(source));
    Assert.assertEquals("MD5 mismatch", md5, pipeAndGetMd5(source));
}

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From source file:org.apache.hadoop.dfs.TestFileCreation.java

/**
 * Test that file data does not become corrupted even in the face of errors.
 *//*  w w  w.j  a  v a 2s  . com*/
public void testFileCreationError1() throws IOException {
    Configuration conf = new Configuration();
    conf.setInt("heartbeat.recheck.interval", 1000);
    conf.setInt("dfs.heartbeat.interval", 1);
    if (simulatedStorage) {
        conf.setBoolean(SimulatedFSDataset.CONFIG_PROPERTY_SIMULATED, true);
    }
    // create cluster
    MiniDFSCluster cluster = new MiniDFSCluster(conf, 1, true, null);
    FileSystem fs = cluster.getFileSystem();
    cluster.waitActive();
    InetSocketAddress addr = new InetSocketAddress("localhost", cluster.getNameNodePort());
    DFSClient client = new DFSClient(addr, conf);

    try {

        // create a new file.
        //
        Path file1 = new Path("/filestatus.dat");
        FSDataOutputStream stm = createFile(fs, file1, 1);

        // verify that file exists in FS namespace
        assertTrue(file1 + " should be a file", fs.getFileStatus(file1).isDir() == false);
        System.out.println("Path : \"" + file1 + "\"");

        // kill the datanode
        cluster.shutdownDataNodes();

        // wait for the datanode to be declared dead
        while (true) {
            DatanodeInfo[] info = client.datanodeReport(FSConstants.DatanodeReportType.LIVE);
            if (info.length == 0) {
                break;
            }
            System.out.println("testFileCreationError1: waiting for datanode " + " to die.");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
        }

        // write 1 byte to file. 
        // This should fail because all datanodes are dead.
        byte[] buffer = new byte[1];
        Random rand = new Random(seed);
        rand.nextBytes(buffer);
        try {
            stm.write(buffer);
            stm.close();
        } catch (Exception e) {
            System.out.println("Encountered expected exception");
        }

        // verify that no blocks are associated with this file
        // bad block allocations were cleaned up earlier.
        LocatedBlocks locations = client.namenode.getBlockLocations(file1.toString(), 0, Long.MAX_VALUE);
        System.out.println("locations = " + locations.locatedBlockCount());
        assertTrue("Error blocks were not cleaned up", locations.locatedBlockCount() == 0);
    } finally {
        cluster.shutdown();
        client.close();
    }
}

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From source file:org.apache.hadoop.io.compress.TestCodec.java

public void testGzipCompatibility() throws IOException {
    Random r = new Random();
    long seed = r.nextLong();
    r.setSeed(seed);// w w w .j  a  va2 s. co  m
    LOG.info("seed: " + seed);

    DataOutputBuffer dflbuf = new DataOutputBuffer();
    GZIPOutputStream gzout = new GZIPOutputStream(dflbuf);
    byte[] b = new byte[r.nextInt(128 * 1024 + 1)];
    r.nextBytes(b);
    gzout.write(b);
    gzout.close();

    DataInputBuffer gzbuf = new DataInputBuffer();
    gzbuf.reset(dflbuf.getData(), dflbuf.getLength());

    Configuration conf = new Configuration();
    conf.setBoolean("hadoop.native.lib", false);
    CompressionCodec codec = ReflectionUtils.newInstance(GzipCodec.class, conf);
    Decompressor decom = codec.createDecompressor();
    assertNotNull(decom);
    assertEquals(BuiltInGzipDecompressor.class, decom.getClass());
    InputStream gzin = codec.createInputStream(gzbuf, decom);

    dflbuf.reset();
    IOUtils.copyBytes(gzin, dflbuf, 4096);
    final byte[] dflchk = Arrays.copyOf(dflbuf.getData(), dflbuf.getLength());
    assertTrue(java.util.Arrays.equals(b, dflchk));
}

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From source file:org.mule.util.queue.AbstractTransactionQueueManagerTestCase.java

@Test
public void testRecoverWarmRestart() throws Exception {
    TransactionalQueueManager mgr = createQueueManager();
    mgr.start();//from  w ww .  ja  v a 2  s  .com
    QueueSession s = mgr.getQueueSession();
    Queue q = s.getQueue("warmRecoverQueue");

    int toPopulate = 500;

    // Populate queue
    Random rnd = new Random();
    for (int j = 0; j < toPopulate; j++) {
        byte[] o = new byte[2048];
        rnd.nextBytes(o);
        q.put(o);
    }
    assertEquals(q.size(), toPopulate);

    // Stop and start TransactionalQueueManager
    mgr.stop();
    mgr.start();

    assertEquals(toPopulate, q.size());
}

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From source file:org.apache.hadoop.hbase.quotas.SpaceQuotaHelperForTests.java

void writeData(TableName tn, long sizeInBytes, byte[] qual) throws IOException {
    final Connection conn = testUtil.getConnection();
    final Table table = conn.getTable(tn);
    try {//from  ww w  .  j av a2  s  . co  m
        List<Put> updates = new ArrayList<>();
        long bytesToWrite = sizeInBytes;
        long rowKeyId = 0L;
        final StringBuilder sb = new StringBuilder();
        final Random r = new Random();
        while (bytesToWrite > 0L) {
            sb.setLength(0);
            sb.append(Long.toString(rowKeyId));
            // Use the reverse counter as the rowKey to get even spread across all regions
            Put p = new Put(Bytes.toBytes(sb.reverse().toString()));
            byte[] value = new byte[SIZE_PER_VALUE];
            r.nextBytes(value);
            p.addColumn(Bytes.toBytes(F1), qual, value);
            updates.add(p);

            // Batch ~13KB worth of updates
            if (updates.size() > 50) {
                table.put(updates);
                updates.clear();
            }

            // Just count the value size, ignore the size of rowkey + column
            bytesToWrite -= SIZE_PER_VALUE;
            rowKeyId++;
        }

        // Write the final batch
        if (!updates.isEmpty()) {
            table.put(updates);
        }

        LOG.debug("Data was written to HBase");
        // Push the data to disk.
        testUtil.getAdmin().flush(tn);
        LOG.debug("Data flushed to disk");
    } finally {
        table.close();
    }
}

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From source file:org.mule.util.queue.AbstractTransactionQueueManagerTestCase.java

@Test
public void testRecoverColdRestart() throws Exception {
    TransactionalQueueManager mgr = createQueueManager();
    QueueSession s = mgr.getQueueSession();
    Queue q = s.getQueue("warmRecoverQueue");
    mgr.start();// ww  w. ja  va 2  s . co  m

    int toPopulate = 500;

    // Populate queue
    Random rnd = new Random();
    for (int j = 0; j < toPopulate; j++) {
        byte[] o = new byte[2048];
        rnd.nextBytes(o);
        q.put(o);
    }
    assertEquals(toPopulate, q.size());

    // Stop and recreate TransactionalQueueManager simulating a cold restart
    mgr.stop();
    mgr = createQueueManager();
    s = mgr.getQueueSession();
    q = s.getQueue("warmRecoverQueue");
    mgr.start();
    if (isPersistent()) {
        assertEquals(toPopulate, q.size());
    } else {
        assertEquals(0, q.size());
    }

}

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From source file:org.apache.hadoop.raid.TestRaidShellFsck.java

/**
 * Creates test file consisting of random data
 *///from   w  w w.  ja va2s.  c  o  m
private void createTestFile(Path filePath) throws IOException {
    Random rand = new Random();
    FSDataOutputStream stm = dfs.create(filePath, true, conf.getInt("io.file.buffer.size", 4096), REPL,
            BLOCK_SIZE);

    final byte[] b = new byte[(int) BLOCK_SIZE];
    for (int i = 0; i < FILE_BLOCKS; i++) {
        rand.nextBytes(b);
        stm.write(b);
    }
    stm.close();
    LOG.info("test file created");

}

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From source file:org.apache.hadoop.hdfs.qjournal.client.TestImageUploadStream.java

/**
 * Write random data by using write(byte) and write(byt[]).
 */// ww  w .ja va2  s  .com
private byte[] writeData(OutputStream os, int size) throws IOException {
    Random r = new Random();
    int approxMaxLen = size;
    int bytesWritten = 0;

    ByteArrayOutputStream bos = new ByteArrayOutputStream();

    while (bytesWritten < approxMaxLen) {
        if (r.nextBoolean()) {
            int b = r.nextInt();
            os.write(b);
            bos.write(b);
            bytesWritten++;
        } else {
            byte[] rand = new byte[r.nextInt(10) + 1];
            r.nextBytes(rand);
            os.write(rand);
            bos.write(rand);
            bytesWritten += rand.length;
        }
    }
    return bos.toByteArray();
}

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