Package fish.payara.nucleus.config

Class ClusteredConfig

java.lang.Object

com.hazelcast.cluster.MembershipAdapter

fish.payara.nucleus.config.ClusteredConfig

All Implemented Interfaces:

com.hazelcast.cluster.MembershipListener, EventListener

@Service
@RunLevel(10)
public class ClusteredConfig
extends com.hazelcast.cluster.MembershipAdapter

The ClusteredConfig can hold configurations that should have a common values that is based on local configuration values but at the same time accessible to all instances in the cluster. Such cases are not supported by the configuration originating from domain.xml. First of all non DAS instances only have their own data available. Secondly with micro instances involved multiple instances can see themselves as the DAS instance each with its own local value. This configurations allows to take a local configuration property and share it with the other instances. The effective value for each instance will be computed from a merge BiFunction on the basis of the local values shared by the other instances.

Since:

5.201

Author:

Jan Bernitt

Constructor Summary

Constructors

Constructor	Description
ClusteredConfig()

Method Summary

Modifier and Type	Method	Description
void	clearSharedConfiguration(String name)	Can be used to clear the shared value of this instance before the instance is shut down.
<T extends Number> T	getSharedConfiguration(String name, T localValue, BiFunction<T,T,T> merge)	Accesses and merges a shared configuration property.
void	memberRemoved(com.hazelcast.cluster.MembershipEvent event)
void	postConstruct()
void	preDestroy()

Methods inherited from class com.hazelcast.cluster.MembershipAdapter

memberAdded

Methods inherited from class java.lang.Object

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

Constructor Detail

ClusteredConfig

public ClusteredConfig()

Method Detail

postConstruct

@PostConstruct
public void postConstruct()

preDestroy

@PreDestroy
public void preDestroy()

getSharedConfiguration

public <T extends Number> T getSharedConfiguration(String name,
                                                   T localValue,
                                                   BiFunction<T,T,T> merge)

Accesses and merges a shared configuration property. Shared configurations are values that use a common value for each instance. The value used is computed by a merge function from all local values when those become relevant. For example a local value of a disabled feature for that instance is not relevant and therefore not considered for the shared value. In practice this means when an instance is accessing a value that is a common or shared configuration it calls this method with its local configuration value which makes it effective for this and other instances.

Parameters:

name - the globally unique name for the configuration property to read

localValue - the value as configured locally or a fallback or default value

merge - the function to use to resolve both local and shared value being present. The resolved value is always going to be the new shared value. If no value was shared so far the local value is always the new shared and result value.

Returns:

the merged value, local value is the default in case no other instances shared the configuration

clearSharedConfiguration

public void clearSharedConfiguration(String name)

Can be used to clear the shared value of this instance before the instance is shut down.

Parameters:

name - the globally unique name for the configuration property to clear

memberRemoved

public void memberRemoved(com.hazelcast.cluster.MembershipEvent event)

Specified by:

memberRemoved in interface com.hazelcast.cluster.MembershipListener

Overrides:

memberRemoved in class com.hazelcast.cluster.MembershipAdapter