Package org.apache.hadoop.io.serializer

Class DeserializerComparator<T>

java.lang.Object

org.apache.hadoop.io.serializer.DeserializerComparator<T>

Type Parameters:

T - generic type.

All Implemented Interfaces:

Comparator<T>, RawComparator<T>

Direct Known Subclasses:

JavaSerializationComparator

@LimitedPrivate({"HDFS","MapReduce"})
@Evolving
public abstract class DeserializerComparator<T>
extends Object
implements RawComparator<T>

A RawComparator that uses a Deserializer to deserialize the objects to be compared so that the standard Comparator can be used to compare them.

One may optimize compare-intensive operations by using a custom implementation of RawComparator that operates directly on byte representations.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	DeserializerComparator(Deserializer<T> deserializer)

Method Summary

Modifier and Type	Method	Description
int	compare(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2)	Compare two objects in binary.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Comparator

compare, equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Constructor Details

DeserializerComparator

protected DeserializerComparator(Deserializer<T> deserializer)
                          throws IOException

Throws:

IOException

Method Details

compare

public int compare(byte[] b1,
 int s1,
 int l1,
 byte[] b2,
 int s2,
 int l2)

Description copied from interface: RawComparator

Compare two objects in binary. b1[s1:l1] is the first object, and b2[s2:l2] is the second object.

Specified by:

compare in interface RawComparator<T>

Parameters:

b1 - The first byte array.

s1 - The position index in b1. The object under comparison's starting index.

l1 - The length of the object in b1.

b2 - The second byte array.

s2 - The position index in b2. The object under comparison's starting index.

l2 - The length of the object under comparison in b2.

Returns:

An integer result of the comparison.