Package org.jgrapes.util

Class ComponentProvider

java.lang.Object

org.jgrapes.core.internal.ComponentVertex

org.jgrapes.core.Component

org.jgrapes.util.ComponentProvider

All Implemented Interfaces:

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

Direct Known Subclasses:

ComponentCollector

public class ComponentProvider
extends Component

Provides child components dynamically using ComponentFactorys.

An instance is configured with a collection of ComponentFactorys (see setFactories(ComponentFactory...)) and component configurations (see setPinned(List) and onConfigurationUpdate(ConfigurationUpdate)).

For each configuration that references a known factory, a component is created and attached to this component provider as child.

Since:

1.3

Nested Class Summary

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

Channel.Default

Field Summary

Fields

Modifier and Type	Field	Description
static final String	COMPONENT_NAME	The entry name for the component’s name.
static final String	COMPONENT_TYPE	The entry name for the component’s 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
ComponentProvider()	Creates a new component with its channel set to this object.
ComponentProvider(Channel componentChannel)	Creates a new component with its channel set to the given channel.

Method Summary

Modifier and Type	Method	Description
protected List<Map<Object,Object>>	componentConfigurations(ConfigurationUpdate evt)	Retrieves the configurations for components to be provided from an entry in a ConfigurationUpdate event.
Map<String,ComponentFactory>	factories()	Gets the factories as a map, indexed by component type.
void	onConfigurationUpdate(ConfigurationUpdate evt)	Uses the information from the event to configure the provided components.
List<Map<Object,Object>>	pinned()	Gets the pinned configurations.
protected Optional<Map<String,Object>>	providerConfiguration(ConfigurationUpdate evt)	Selects configuration information targeted at this component from the event.
ComponentProvider	setComponentsEntry(String name)	Sets the name of the entry in this component’s configuration information (as returned by providerConfiguration(ConfigurationUpdate)) that holds the information about the components to be provided.
ComponentProvider	setFactories(ComponentFactory... factories)	Sets the factories that this provider knows about.
ComponentProvider	setPinned(List<Map<?,?>> pinnedConfigurations)	Sets the pinned configurations.

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

Field Details

COMPONENT_TYPE

public static final String COMPONENT_TYPE

The entry name for the component’s type.

See Also:

• Constant Field Values

COMPONENT_NAME

public static final String COMPONENT_NAME

The entry name for the component’s name.

See Also:

• Constant Field Values

Constructor Details

ComponentProvider

public ComponentProvider()

Creates a new component with its channel set to this object.

ComponentProvider

public ComponentProvider(Channel componentChannel)

Creates a new component with its channel set to the given channel.

Parameters:

componentChannel - the channel that the component’s handlers listen on by default and that Manager.fire(Event, Channel...) sends the event to

Method Details

setComponentsEntry

public ComponentProvider setComponentsEntry(String name)

Sets the name of the entry in this component’s configuration information (as returned by providerConfiguration(ConfigurationUpdate)) that holds the information about the components to be provided.

Defaults to “components”.

If set to null, handling ConfigurationUpdate events is effectively disabled (unless componentConfigurations(ConfigurationUpdate) is overridden by a method that ignores the setting).

Parameters:

name - the name of the entry

Returns:

the component provider for easy chaining

setFactories

public ComponentProvider setFactories(ComponentFactory... factories)

Sets the factories that this provider knows about.

Only configurations with a component type that matches one of the factories are handled by this provider.

Parameters:

factories - the factories

Returns:

the component provider for easy chaining

factories

public Map<String,ComponentFactory> factories()

Gets the factories as a map, indexed by component type.

Returns:

the factories

setPinned

public ComponentProvider setPinned(List<Map<?,?>> pinnedConfigurations)

Sets the pinned configurations.

Components provided due to these configurations exist independent of any information passed by ConfigurationUpdate events.

Parameters:

pinnedConfigurations - the configurations to be pinned

Returns:

the component provider for easy chaining

pinned

public List<Map<Object,Object>> pinned()

Gets the pinned configurations.

Returns:

the pinned configurations

providerConfiguration

protected Optional<Map<String,Object>> providerConfiguration(ConfigurationUpdate evt)

Selects configuration information targeted at this component from the event.

The default implementation invokes ConfigurationUpdate.structured(String) with this component’s path to obtain the information. Called by componentConfigurations(ConfigurationUpdate).

Parameters:

evt - the event

Returns:

the configuration information as provided by ConfigurationUpdate.structured(String) if it exists

componentConfigurations

protected List<Map<Object,Object>> componentConfigurations(ConfigurationUpdate evt)

Retrieves the configurations for components to be provided from an entry in a ConfigurationUpdate event.

Overriding this method enables derived classes to fully control how this information is retrieved from the ConfigurationUpdate event.

This implementation of the method calls providerConfiguration(ConfigurationUpdate) to obtain all configuration information targeted at this component provider. It then uses the configured entry (see setComponentsEntry(String)) to retrieve the information about the components to be provided.

The method must ensure that the result is a collection of maps, where each map has at least entries with keys “componentType” and “name”, each associated with a value of type String.

Parameters:

evt - the event

Returns:

the collection

onConfigurationUpdate

@Handler
public void onConfigurationUpdate(ConfigurationUpdate evt)

Uses the information from the event to configure the provided components.

Parameters:

evt - the event

See Also:

• componentConfigurations(ConfigurationUpdate)