Package org.infinispan.counter.impl.weak

Class WeakCounterImpl

java.lang.Object

org.infinispan.counter.impl.weak.WeakCounterImpl

All Implemented Interfaces:

org.infinispan.counter.api.WeakCounter, CounterEventGenerator, TopologyChangeListener

public class WeakCounterImpl
extends Object
implements org.infinispan.counter.api.WeakCounter, CounterEventGenerator, TopologyChangeListener

A weak consistent counter implementation.

Implementation: The counter is split in multiple keys and they are stored in the cache.

Write: A write operation will pick a key to update. If the node is a primary owner of one of the key, that key is chosen based on thread-id. This will take advantage of faster write operations. If the node is not a primary owner, one of the key in key set is chosen.

Read: A read operation needs to read all the key set (including the remote keys). This is slower than atomic counter.

Weak Read: A snapshot of all the keys values is kept locally and they are updated via cluster listeners.

Reset: The reset operation is not atomic and intermediate results may be observed.

Since:

9.0

Author:

Pedro Ruivo

Constructor Summary

Constructors

Constructor	Description
WeakCounterImpl(String counterName, org.infinispan.AdvancedCache<WeakCounterKey,CounterValue> cache, org.infinispan.counter.api.CounterConfiguration configuration, CounterManagerNotificationManager notificationManager)

Method Summary

Modifier and Type	Method	Description
CompletableFuture<Void>	add(long delta)
<T extends org.infinispan.counter.api.CounterListener> org.infinispan.counter.api.Handle<T>	addListener(T listener)
void	destroyAndRemove()
org.infinispan.counter.api.CounterEvent	generate(CounterKey key, CounterValue value)	It generates the CounterEvent.
org.infinispan.counter.api.CounterConfiguration	getConfiguration()
WeakCounterKey[]	getKeys()	Debug only!
String	getName()
WeakCounterKey[]	getPreferredKeys()	Debug only!
long	getValue()
void	init()	Initializes the key set.
CompletableFuture<Void>	remove()
static void	removeWeakCounter(org.infinispan.Cache<WeakCounterKey,CounterValue> cache, org.infinispan.counter.api.CounterConfiguration configuration, String counterName)	It removes a weak counter from the cache, identified by the counterName.
CompletableFuture<Void>	reset()
org.infinispan.counter.api.SyncWeakCounter	sync()
void	topologyChanged()	It notifies the cache topology change.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.infinispan.counter.api.WeakCounter

decrement, increment

Constructor Detail

WeakCounterImpl

public WeakCounterImpl(String counterName,
                       org.infinispan.AdvancedCache<WeakCounterKey,CounterValue> cache,
                       org.infinispan.counter.api.CounterConfiguration configuration,
                       CounterManagerNotificationManager notificationManager)

Method Detail

removeWeakCounter

public static void removeWeakCounter(org.infinispan.Cache<WeakCounterKey,CounterValue> cache,
                                     org.infinispan.counter.api.CounterConfiguration configuration,
                                     String counterName)

It removes a weak counter from the cache, identified by the counterName.

Parameters:

cache - The Cache to remove the counter from.

configuration - The counter's configuration.

counterName - The counter's name.

init

public void init()

Initializes the key set.

Only one key will have the initial value and the remaining is zero.

getName

public String getName()

Specified by:

getName in interface org.infinispan.counter.api.WeakCounter

getValue

public long getValue()

Specified by:

getValue in interface org.infinispan.counter.api.WeakCounter

add

public CompletableFuture<Void> add(long delta)

Specified by:

add in interface org.infinispan.counter.api.WeakCounter

reset

public CompletableFuture<Void> reset()

Specified by:

reset in interface org.infinispan.counter.api.WeakCounter

addListener

public <T extends org.infinispan.counter.api.CounterListener> org.infinispan.counter.api.Handle<T> addListener(T listener)

Specified by:

addListener in interface org.infinispan.counter.api.WeakCounter

getConfiguration

public org.infinispan.counter.api.CounterConfiguration getConfiguration()

Specified by:

getConfiguration in interface org.infinispan.counter.api.WeakCounter

generate

public org.infinispan.counter.api.CounterEvent generate(CounterKey key,
                                                        CounterValue value)

Description copied from interface: CounterEventGenerator

It generates the CounterEvent.

The value is the new value of CounterEvent.

Specified by:

generate in interface CounterEventGenerator

Parameters:

key - The counter's key.

value - The counter's most recent CounterValue.

Returns:

The CounterEvent with the updated value.

remove

public CompletableFuture<Void> remove()

Specified by:

remove in interface org.infinispan.counter.api.WeakCounter

sync

public org.infinispan.counter.api.SyncWeakCounter sync()

Specified by:

sync in interface org.infinispan.counter.api.WeakCounter

destroyAndRemove

public void destroyAndRemove()

topologyChanged

public void topologyChanged()

Description copied from interface: TopologyChangeListener

It notifies the cache topology change.

Specified by:

topologyChanged in interface TopologyChangeListener

getPreferredKeys

public WeakCounterKey[] getPreferredKeys()

Debug only!

getKeys

public WeakCounterKey[] getKeys()

Debug only!

toString

public String toString()

Overrides:

toString in class Object