Package org.jgrapes.osgi.core

Class ComponentCollector<F extends ComponentFactory>

java.lang.Object

org.jgrapes.core.internal.ComponentVertex

org.jgrapes.core.Component

org.jgrapes.util.ComponentProvider

org.jgrapes.osgi.core.ComponentCollector<F>

Type Parameters:

F - the component factory type

All Implemented Interfaces:

Iterable<ComponentType>, Channel, ComponentType, Eligible, Manager, ServiceTrackerCustomizer<F,F>

public class ComponentCollector<F extends ComponentFactory>
extends ComponentProvider
implements ServiceTrackerCustomizer<F,F>

A component that collects all services from the OSGi service registry which implement the sub-interface of ComponentFactory specified when creating the collector.

The collector uses each service found to create one or more Components that are then attached to the component collector instance.

Effectively, the component collector leverages OSGi’s service layer to modify the component tree at run-time.

This class uses ComponentProvider.setFactories(ComponentFactory...) and ComponentProvider.setPinned(List) for its implementation. As it inherits from ComponentProvider, it automatically supports the provisioning of additional components through ConfigurationUpdate events. If this is not desired, invoke ComponentProvider.setComponentsEntry(String) with null as argument.

Nested Class Summary

Nested classes/interfaces inherited from interface org.jgrapes.core.Channel

Channel.Default

Field Summary

Fields inherited from class org.jgrapes.util.ComponentProvider

COMPONENT_NAME, COMPONENT_TYPE

Fields inherited from class org.jgrapes.core.Component

logger

Fields inherited from interface org.jgrapes.core.Channel

BROADCAST, SELF

Constructor Summary

Constructors

Constructor	Description
ComponentCollector(Channel componentChannel, BundleContext context, Class<F> factoryClass)	Utility constructor that uses each factory to create a single instance, using an empty map as properties.
ComponentCollector(Channel componentChannel, BundleContext context, Class<F> factoryCls, Function<String,List<Map<Object,Object>>> configurator)	Creates a collector component that uses a ServiceTracker to monitor the addition and removal of component factories.

Method Summary

Modifier and Type	Method	Description
F	addingService(ServiceReference<F> reference)	Whenever a new factory is added, it is used to create component instances with this component’s channel.
void	modifiedService(ServiceReference<F> reference, F service)
void	removedService(ServiceReference<F> reference, F service)	Deletes all child components with the type produced by the factory that is removed.

Methods inherited from class org.jgrapes.util.ComponentProvider

componentConfigurations, factories, onConfigurationUpdate, pinned, providerConfiguration, setComponentsEntry, setFactories, setPinned

Methods inherited from class org.jgrapes.core.Component

channel, component, defaultCriterion, isEligibleFor, setName

Methods inherited from class org.jgrapes.core.internal.ComponentVertex

activeEventPipeline, addHandler, attach, children, componentPath, componentVertex, detach, fire, initComponentsHandlers, iterator, name, newEventPipeline, newEventPipeline, parent, registerAsGenerator, root, toString, unregisterAsGenerator

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface org.jgrapes.core.Manager

stream

Constructor Details

ComponentCollector

public ComponentCollector(Channel componentChannel,
 BundleContext context,
 Class<F> factoryCls,
 Function<String,List<Map<Object,Object>>> configurator)

Creates a collector component that uses a ServiceTracker to monitor the addition and removal of component factories.

Parameters:

componentChannel - this component’s channel

context - the OSGi BundleContext

factoryCls - the factory class

configurator - the function that provides the pinned configurations

See Also:

• addingService(ServiceReference)
• removedService(ServiceReference, ComponentFactory)

ComponentCollector

public ComponentCollector(Channel componentChannel,
 BundleContext context,
 Class<F> factoryClass)

Utility constructor that uses each factory to create a single instance, using an empty map as properties.

Parameters:

componentChannel - this component’s channel

context - the bundle context

factoryClass - the factory class

Method Details

addingService

public F addingService(ServiceReference<F> reference)

Whenever a new factory is added, it is used to create component instances with this component’s channel.

First, the configurator passed to the constructor is invoked with the name of the class of the component to be created as argument. The list of maps returned is then added to the pinned components (see ComponentProvider.setPinned(List)).

The map return from the configurator is automatically augmented with an entry with key BundleContext.class and the bundle context passed to the constructor.

Specified by:

addingService in interface ServiceTrackerCustomizer<F extends ComponentFactory,F extends ComponentFactory>

See Also:

• ServiceTrackerCustomizer.addingService(ServiceReference)

modifiedService

public void modifiedService(ServiceReference<F> reference,
 F service)

Specified by:

modifiedService in interface ServiceTrackerCustomizer<F extends ComponentFactory,F extends ComponentFactory>

removedService

public void removedService(ServiceReference<F> reference,
 F service)

Deletes all child components with the type produced by the factory that is removed.

A (possibly) final Stop event is send to the detached subtrees which may be used to deactivate bundles.

Specified by:

removedService in interface ServiceTrackerCustomizer<F extends ComponentFactory,F extends ComponentFactory>

See Also:

• ServiceTrackerCustomizer.removedService(ServiceReference, Object)