org.apache.hadoop.hdfs.util
Class EnumCounters<E extends Enum<E>>

java.lang.Object
  org.apache.hadoop.hdfs.util.EnumCounters<E>

Type Parameters:

E - the enum type

Direct Known Subclasses:

Content.Counts, Quota.Counts

public class EnumCounters<E extends Enum<E>>
extends Object

Counters for an enum type. For example, suppose there is an enum type

 enum Fruit { APPLE, ORANGE, GRAPE }
 

An EnumCounters object can be created for counting the numbers of APPLE, ORANGLE and GRAPE.

Nested Class Summary

static interface	EnumCounters.Factory<E extends Enum<E>,C extends EnumCounters<E>> A factory for creating counters.
static class	EnumCounters.Map<K,E extends Enum<E>,C extends EnumCounters<E>> A key-value map which maps the keys to EnumCounters.

Constructor Summary

EnumCounters(Class<E> enumClass)
Construct counters for the given enum constants.

Method Summary

void	add(E e, long value) Add the given value to counter e.
void	add(EnumCounters<E> that) Add that counters to this counters.
boolean	equals(Object obj)
long	get(E e)
int	hashCode()
void	negation() Negate all counters.
void	reset() Reset all counters to zero.
void	set(E e, long value) Set counter e to the given value.
void	set(EnumCounters<E> that) Set this counters to that counters.
void	subtract(E e, long value) Subtract the given value from counter e.
void	subtract(EnumCounters<E> that) Subtract this counters from that counters.
long	sum()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

EnumCounters

public EnumCounters(Class<E> enumClass)

Construct counters for the given enum constants.

Parameters:

enumClass - the enum class of the counters.

Method Detail

get

public final long get(E e)

Returns:

the value of counter e.

negation

public final void negation()

Negate all counters.

set

public final void set(E e,
                      long value)

Set counter e to the given value.

set

public final void set(EnumCounters<E> that)

Set this counters to that counters.

reset

public final void reset()

Reset all counters to zero.

add

public final void add(E e,
                      long value)

Add the given value to counter e.

add

public final void add(EnumCounters<E> that)

Add that counters to this counters.

subtract

public final void subtract(E e,
                           long value)

Subtract the given value from counter e.

subtract

public final void subtract(EnumCounters<E> that)

Subtract this counters from that counters.

sum

public final long sum()

Returns:

the sum of all counters.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object