Java WritableComparator.hashBytes方法代碼示例

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
/** 
 * Use (the specified slice of the array returned by) 
 * {@link BinaryComparable#getBytes()} to partition. 
 */
@Override
public int getPartition(BinaryComparable key, V value, int numPartitions) {
  int length = key.getLength();
  int leftIndex = (leftOffset + length) % length;
  int rightIndex = (rightOffset + length) % length;
  int hash = WritableComparator.hashBytes(key.getBytes(), 
    leftIndex, rightIndex - leftIndex + 1);
  return (hash & Integer.MAX_VALUE) % numPartitions;
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
@Override
public int hashCode() {
  return WritableComparator.hashBytes(keyBuffer, 0, getKeyLength());
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
public int hashCode() {
    return WritableComparator.hashBytes(this.getBytes(), this.getLength());
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
@SuppressWarnings("unchecked")
public void map(WritableComparable key, Writable value,
                OutputCollector<IntWritable, RecordStatsWritable> output, 
                Reporter reporter) throws IOException {
  // Set up rawKey and rawValue on the first call to 'map'
  if (recordId == -1) {
   rawKey = createRaw(key.getClass());
   rawValue = createRaw(value.getClass());
  }
  ++recordId;
  
  if (this.key == sortOutput) {
    // Check if keys are 'sorted' if this  
    // record is from sort's output
    if (prevKey == null) {
      prevKey = key;
      keyClass = prevKey.getClass();
    } else {
      // Sanity check
      if (keyClass != key.getClass()) {
        throw new IOException("Type mismatch in key: expected " +
                              keyClass.getName() + ", received " +
                              key.getClass().getName());
      }
      
      // Check if they were sorted correctly
      if (prevKey.compareTo(key) > 0) {
        throw new IOException("The 'map-reduce' framework wrongly" +
                              " classifed (" + prevKey + ") > (" + 
                              key + ") "+ "for record# " + recordId); 
      }
      prevKey = key;
    }

    // Check if the sorted output is 'partitioned' right
    int keyPartition = 
      partitioner.getPartition(key, value, noSortReducers);
    if (partition != keyPartition) {
      throw new IOException("Partitions do not match for record# " + 
                            recordId + " ! - '" + partition + "' v/s '" + 
                            keyPartition + "'");
    }
  }

  // Construct the record-stats and output (this.key, record-stats)
  byte[] keyBytes = rawKey.getRawBytes(key);
  int keyBytesLen = rawKey.getRawBytesLength(key);
  byte[] valueBytes = rawValue.getRawBytes(value);
  int valueBytesLen = rawValue.getRawBytesLength(value);
  
  int keyValueChecksum = 
    (WritableComparator.hashBytes(keyBytes, keyBytesLen) ^
     WritableComparator.hashBytes(valueBytes, valueBytesLen));

  output.collect(this.key, 
                 new RecordStatsWritable((keyBytesLen+valueBytesLen),
                 1, keyValueChecksum)
                );
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
@Override
public int hashCode() {
    return WritableComparator.hashBytes(ba.bytes(), ba.length());
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
/**
 * Return a hash of the bytes returned from {#getBytes()}.
 * @see org.apache.hadoop.io.WritableComparator#hashBytes(byte[],int)
 */
public int hashCode() {
  return WritableComparator.hashBytes(getBytes(), getLength());
}
 

import org.apache.hadoop.io.WritableComparator; //導入方法依賴的package包/類
/**
 * @param b value
 * @param length length of the value
 * @return Runs {@link WritableComparator#hashBytes(byte[], int)} on the
 * passed in array.  This method is what {@link org.apache.hadoop.io.Text} and
 * {@link org.apache.hadoop.hbase.io.ImmutableBytesWritable} use calculating hash code.
 */
public static int hashCode(final byte [] b, final int length) {
  return WritableComparator.hashBytes(b, length);
}