com.hazelcast.util.counters
Class SwCounter

java.lang.Object
  com.hazelcast.util.counters.SwCounter

All Implemented Interfaces:

Counter

public abstract class SwCounter
extends Object
implements Counter

A Counter that is made to be used by a single writing thread. It makes use of the lazy-set to provide a lower overhead than a volatile write on X86 systems. The volatile write requires waiting for the store buffer to be drained which isn't needed for the lazySet. This counter does not provide padding to prevent false sharing. You might wonder why not to use the AtomicLong.inc; the problem here is that it requires a full fence (so waiting for store and load buffers to be drained). This is more expensive. You might wonder why not to use the following:

     atomicLong.lazySet(atomicLong.get()+1)
 

This causes a lot of syntactic noise due to lack of abstraction. A counter.inc() gives a better clue what the intent is.

Method Summary

static SwCounter	newSwCounter() Creates a new SwCounter with 0 as initial value.
static SwCounter	newSwCounter(int initialValue) Creates a new SwCounter with the given initial value.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.hazelcast.util.counters.Counter

get, inc, inc

Method Detail

newSwCounter

public static SwCounter newSwCounter()

Creates a new SwCounter with 0 as initial value.

Returns:

the created SwCounter.

newSwCounter

public static SwCounter newSwCounter(int initialValue)

Creates a new SwCounter with the given initial value.

Returns:

the created SwCounter.