【原】MapReduce的排序和二次排序

public class IntWritable implements WritableComparable {
  private int value;

  public IntWritable() {}

  public IntWritable(int value) { set(value); }

  /** Set the value of this IntWritable. */
  public void set(int value) { this.value = value; }

  /** Return the value of this IntWritable. */
  public int get() { return value; }

  public void readFields(DataInput in) throws IOException {
    value = in.readInt();
  }

  public void write(DataOutput out) throws IOException {
    out.writeInt(value);
  }

  /** Returns true iff <code>o</code> is a IntWritable with the same value. */
  public boolean equals(Object o) {
    if (!(o instanceof IntWritable))
      return false;
    IntWritable other = (IntWritable)o;
    return this.value == other.value;
  }

  public int hashCode() {
    return value;
  }

  /** Compares two IntWritables. */
  public int compareTo(Object o) {
    int thisValue = this.value;
    int thatValue = ((IntWritable)o).value;
    return (thisValue<thatValue ? -1 : (thisValue==thatValue ? 0 : 1));
  }

  public String toString() {
    return Integer.toString(value);
  }
}