io.helixservice.core.feature

Class AbstractFeature

java.lang.Object

io.helixservice.core.feature.AbstractFeature

All Implemented Interfaces:

ComponentRegistry, Feature

Direct Known Subclasses:

BlockingWorkerFeature, VertxNativeFeature

public abstract class AbstractFeature
extends Object
implements Feature

Abstract base class from which all features should derive, as it provides common functionality and default implementations.

Constructor Summary

Constructors

Constructor and Description
AbstractFeature() Construct the feature, setting the feature name based on the Java class name.
AbstractFeature(String featureName) Construct this feature, with the provided feature name

Method Summary

Modifier and Type	Method and Description
<T extends Component> Collection<T>	findByType(String componentType) Find a list of components by type name
<T extends Component> T	findByType(String componentType, T defaultValue) Finds the a registered component by type name.
void	finish(Server server) Called by Helix Server when the server going to stop.
String	getFeatureName() Get this feature's name for debugging and logging
com.google.common.collect.Multimap<String,Component>	getRegistrationMap() Returns a map of registered components owned by this feature
void	logFeatureDetails(org.slf4j.Logger logger) Logs the feature configuration to the provided logger.
void	register(Component... componentArray) Register component(s) created and owned by this feature
void	start(Server server) Called by Helix Server when the server is starting.
void	stop(Server server) Called by Helix Server when the server has stopped.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractFeature

public AbstractFeature()

Construct the feature, setting the feature name based on the Java class name.

AbstractFeature

public AbstractFeature(String featureName)

Construct this feature, with the provided feature name

Parameters:

featureName - Feature name

Method Detail

getFeatureName

public String getFeatureName()

Get this feature's name for debugging and logging

Specified by:

getFeatureName in interface Feature

Returns:

The feature's name

register

public void register(Component... componentArray)

Register component(s) created and owned by this feature

Components registered here are in a registry local to this feature. These components will also be automatically aggregated and registered with the HelixServer top-level registry.

If a component contains other components, then the entire tree of components will be registered.

Parameters:

componentArray - Array of components to register

getRegistrationMap

public com.google.common.collect.Multimap<String,Component> getRegistrationMap()

Returns a map of registered components owned by this feature

Specified by:

getRegistrationMap in interface ComponentRegistry

Returns:

The map of components, where key is the component type name.

findByType

public <T extends Component> Collection<T> findByType(String componentType)

Find a list of components by type name

Specified by:

findByType in interface ComponentRegistry

Type Parameters:

T - Resulting class of the components expected

Parameters:

componentType - Type name of the components to find

Returns:

A collection of the components found, or empty list of none is found.

findByType

public <T extends Component> T findByType(String componentType,
                                          T defaultValue)

Finds the a registered component by type name. This method guarantees that the last (most recently) registered component will be returned.

Specified by:

findByType in interface ComponentRegistry

Type Parameters:

T - Resulting class of the component expected

Parameters:

componentType - Type name of the component to find

defaultValue - Default component if none is found (null is okay)

Returns:

The found component, or the default component if no component was found.

logFeatureDetails

public void logFeatureDetails(org.slf4j.Logger logger)

Logs the feature configuration to the provided logger.

This implements a generic way of logging features, so subclasses should not need to implement their own logging code.

Specified by:

logFeatureDetails in interface Feature

Parameters:

logger - Logger to write the feature details to

start

public void start(Server server)

Called by Helix Server when the server is starting.

The order features will be called is the same order they initially registered with Helix. At the time this method is called, Vert.x will be initialized enabling the feature to create any Vert.x related resources.

Features should create and register any singleton components and allocate resources during the start call. Blocking operations are allowed in this method.

Specified by:

start in interface Feature

Parameters:

server - Helix Server that is starting up

finish

public void finish(Server server)

Called by Helix Server when the server going to stop.

The order features will be called is the reverse order they initially registered with Helix. Features should NOT release resources at this point.

Stop accepting new requests, and finish all ongoing requests. There will be a configurable delay between the finish and stop lifecycle callbacks to enable the server to finish in-flight requests.

Specified by:

finish in interface Feature

Parameters:

server - Helix Server that is finishing in-flight requests

stop

public void stop(Server server)

Called by Helix Server when the server has stopped.

The order features will be called is the reverse order they initially registered with Helix. Features must release all owned resources at this point. Blocking operations are allowed in this method.

Specified by:

stop in interface Feature

Parameters:

server - Helix Server that is being stopped