Package org.apache.hadoop.hdfs.server.federation.resolver

Class NamenodePriorityComparator

java.lang.Object

org.apache.hadoop.hdfs.server.federation.resolver.NamenodePriorityComparator

All Implemented Interfaces:

Serializable, Comparator<FederationNamenodeContext>

public class NamenodePriorityComparator
extends Object
implements Comparator<FederationNamenodeContext>, Serializable

Compares NNs in the same namespace and prioritizes by their status. The priorities are:

• ACTIVE
• STANDBY
• UNAVAILABLE

When two NNs have the same state, the last modification date is the tie breaker, newest has priority. Expired NNs are excluded.

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
NamenodePriorityComparator()

Method Summary

Modifier and Type	Method	Description
int	compare(FederationNamenodeContext o1, FederationNamenodeContext o2)

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

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

Constructor Details

NamenodePriorityComparator

public NamenodePriorityComparator()

Method Details

compare

public int compare(FederationNamenodeContext o1,
 FederationNamenodeContext o2)

Specified by:

compare in interface Comparator<FederationNamenodeContext>