com.bigdata.counters

Class CAT

java.lang.Object

com.bigdata.counters.CAT

All Implemented Interfaces:

Externalizable, Serializable

public class CAT
extends Object
implements Externalizable

An alias for the high-scale-lib counter implementation. CATs are useful when a counter is extremely hot for updates and adaptively expand their internal state to minimize thread contention. However, they can do more work than an AtomicLong on read since they must scan an internal table to aggregate updates from various threads.

Note: The class uses a delegation pattern in order to replace the serialization logic with a simple serialized long value.

Version:

$Id$

Author:

Bryan Thompson

See Also:

ConcurrentAutoTable, Serialized Form

Constructor Summary

Constructors

Constructor and Description
CAT() Initialize a new counter with a value of 0L.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(long x) Add the value to the counter.
void	decrement() Decrement the value of the counter.
long	estimate_get() Estimate the current value of the counter.
long	get() Current value of the counter.
void	increment() Increment the value of the counter.
void	readExternal(ObjectInput in)
void	set(long x) Set the value of the counter.
String	toString() Return the current value of the counter.
void	writeExternal(ObjectOutput out)

Methods inherited from class java.lang.Object

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

Constructor Detail

CAT

public CAT()

Initialize a new counter with a value of 0L.

Method Detail

add

public final void add(long x)

Add the value to the counter.

See Also:

ConcurrentAutoTable.add(long)

decrement

public final void decrement()

Decrement the value of the counter.

See Also:

ConcurrentAutoTable.decrement()

increment

public final void increment()

Increment the value of the counter.

See Also:

ConcurrentAutoTable.increment()

set

public final void set(long x)

Set the value of the counter.

See Also:

ConcurrentAutoTable.set(long)

get

public final long get()

Current value of the counter.

See Also:

ConcurrentAutoTable.get()

estimate_get

public final long estimate_get()

Estimate the current value of the counter.

See Also:

ConcurrentAutoTable.estimate_get()

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

toString

public String toString()

Return the current value of the counter.

Overrides:

toString in class Object