Package org.jgroups.blocks.atomic

Interface SyncCounter

All Superinterfaces:

BaseCounter

All Known Subinterfaces:

Counter

public interface SyncCounter
extends BaseCounter

A synchronous counter interface

Since:

5.2

Author:

Bela Ban, Pedro Ruivo

Method Summary

Modifier and Type	Method	Description
long	addAndGet(long delta)	Atomically adds the given value to the current value.
default boolean	compareAndSet(long expect, long update)	Atomically updates the counter using a CAS operation
long	compareAndSwap(long expect, long update)	Atomically updates the counter using a compare-and-swap operation.
default long	decrementAndGet()	Atomically decrements the counter and returns the new value
long	get()	Gets the current value of the counter
default long	incrementAndGet()	Atomically increments the counter and returns the new value
void	set(long new_value)	Sets the counter to a new value
default SyncCounter	sync()	Returns a SyncCounter wrapper for this instance.
default <T extends Streamable> T	update(CounterFunction<T> updateFunction)	Atomically updates the counter's value.

Methods inherited from interface org.jgroups.blocks.atomic.BaseCounter

async, getName

Method Detail

get

long get()

Gets the current value of the counter

Returns:

The current value

set

void set(long new_value)

Sets the counter to a new value

Parameters:

new_value - The new value

compareAndSet

default boolean compareAndSet(long expect,
                              long update)

Atomically updates the counter using a CAS operation

Parameters:

expect - The expected value of the counter

update - The new value of the counter

Returns:

True if the counter could be updated, false otherwise

compareAndSwap

long compareAndSwap(long expect,
                    long update)

Atomically updates the counter using a compare-and-swap operation.

Parameters:

expect - The expected value of the counter

update - The new value of the counter

Returns:

The previous value of the counter

incrementAndGet

default long incrementAndGet()

Atomically increments the counter and returns the new value

Returns:

The new value

decrementAndGet

default long decrementAndGet()

Atomically decrements the counter and returns the new value

Returns:

The new value

addAndGet

long addAndGet(long delta)

Atomically adds the given value to the current value.

Parameters:

delta - the value to add

Returns:

the updated value

update

default <T extends Streamable> T update(CounterFunction<T> updateFunction)

Atomically updates the counter's value.

Both CounterFunction and return value must implement Streamable to be sent over the network. The function should not block thread since it can cause deadlocks neither invoke any operation over the SyncCounter.

The CounterView is a copy of the counter's value and the last CounterView.set(long) will be applied to the counter.

Type Parameters:

T - The return value type.

Parameters:

updateFunction - The update CounterFunction.

Returns:

The function's return value.

See Also:

CounterFunction, CounterView, LongSizeStreamable

sync

default SyncCounter sync()

Description copied from interface: BaseCounter

Returns a SyncCounter wrapper for this instance. If this counter is already synchronous, then this counter instance is returned (no-op)

Specified by:

sync in interface BaseCounter

Returns:

The SyncCounter instance;