com.hazelcast.instance

Class NodeExtensionFactory

java.lang.Object

com.hazelcast.instance.NodeExtensionFactory

@PrivateApi
public final class NodeExtensionFactory
extends Object

Method Summary

Modifier and Type	Method and Description
static NodeExtension	create(Node node, List<String> extensionPriorityList) Uses the Hazelcast ServiceLoader to discover all registered NodeExtension classes and identify the one to instantiate and use as the provided node's extension.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static NodeExtension create(Node node,
                                   List<String> extensionPriorityList)

Uses the Hazelcast ServiceLoader to discover all registered NodeExtension classes and identify the one to instantiate and use as the provided node's extension. It chooses the class based on the provided priority list of class names, these are the rules:

1. A class's priority is its zero-based index in the list.
2. Lower number means higher priority.
3. A class that doesn't appear in the list doesn't qualify for selection.

The dynamic selection of the node extension allows Hazelcast Enterprise's JAR to be swapped in for the core Hazelcast JAR with no changes to user's code or configuration. Hazelcast core code can call this method with a priority list naming both the default and the enterprise node extension and it will automatically prefer the Enterprise one when present.

The explicit priority list is necessary because a Hazelcast Jet JAR contains both the default node extension and the Jet node extension, but the one to choose depends on whether the user is requesting to start an IMDG or a Jet instance.

Parameters:

node - Hazelcast node whose extension this method must provide

extensionPriorityList - priority list of fully qualified extension class names

Returns:

the selected node extension