Example usage for org.apache.hadoop.io LongWritable hashCode

Introduction

In this page you can find the example usage for org.apache.hadoop.io LongWritable hashCode.

Prototype

@Override
    public int hashCode() 

Source Link

Usage

From source file:org.apache.giraph.mapping.AbstractLongByteOps.java

License:Apache License

/**
 * Compute partition given id, partitionCount, workerCount & target
 * @param id vertex id/*from w  w  w. ja  v a  2s .  c  o m*/
 * @param partitionCount number of partitions
 * @param workerCount number of workers
 * @param target target worker
 * @return partition number
 */
protected int computePartition(LongWritable id, int partitionCount, int workerCount, byte target) {
    int numRows = partitionCount / workerCount;
    numRows = (numRows * workerCount == partitionCount) ? numRows : numRows + 1;
    if (target == -1) {
        // default to hash based partitioning
        return Math.abs(id.hashCode() % partitionCount);
    } else {
        int targetWorker = target & 0xFF;
        // assume zero based indexing of partition & worker [also consecutive]
        return numRows * targetWorker + Math.abs(id.hashCode() % numRows);
    }
}

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From source file:org.shadowmask.engine.hive.udf.UDFHashTest.java

License:Apache License

@Test
public void testUDFHash() {
    UDFHash udfHash = new UDFHash();
    Text data1 = new Text("hello");
    IntWritable result = udfHash.evaluate(data1);
    assertEquals(data1.hashCode(), result.get());
    LongWritable data2 = new LongWritable(80000000000L);
    result = udfHash.evaluate(data2);/*from w w  w .j av  a  2s.  c  o m*/
    assertEquals(data2.hashCode(), result.get());
    IntWritable data3 = new IntWritable(345);
    result = udfHash.evaluate(data3);
    assertEquals(data3.hashCode(), result.get());

    data3 = null;
    result = udfHash.evaluate(data3);
    assertNull(result);
}

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