org.mule.extension

Interface ExtensionManager

public interface ExtensionManager

Manages the Extensions available in the current context and their state. Going beyond the introspection model defined by Extension, Configuration and Operation class, at runtime there will be instances implementing the extension components modeled by them. Those instances need to be registered with this manager in order to be used.

The workflow for this manager would be to first discover the currently available extensions through discoverExtensions(ClassLoader). Additionally, Extension instances can also be added in runtime through registerExtension(Extension).

Instances serving as realization of a Configuration model need to be registered with the registerConfigurationInstanceProvider(Extension, String, ConfigurationInstanceProvider) method in order for this manager to provision the underlying infrastructure to host and execute such configuration.

Since:

1.0

Method Summary

Methods

Modifier and Type	Method and Description
List<Extension>	discoverExtensions(ClassLoader classLoader) Scans the classpath visible to the given ClassLoader and registers them.
Set<Extension>	getExtensions() Returns a Set listing all the discovered Extensions.
<C> Set<Extension>	getExtensionsCapableOf(Class<C> capability) Returns a Set with the Extensions that have the given capability
<C> void	registerConfigurationInstanceProvider(Extension extension, String providerName, ConfigurationInstanceProvider<C> configurationInstanceProvider) Registers the configurationInstanceProvider.
boolean	registerExtension(Extension extension) Registers the given Extension If a matching Extension is already registered, then this manager will apply whatever policy finds more convenient to decide if the existing registration is kept or replaced.

Method Detail

discoverExtensions

List<Extension> discoverExtensions(ClassLoader classLoader)

Scans the classpath visible to the given ClassLoader and registers them.

The discovery process works as follows:

• Some discovery mechanism (which one is up to the implementation) is used to discover implementations of the Describer interface
• The discovered describers are fed into a ExtensionFactory and transformed in Extension instances
• Those extensions are registered through the registerExtension(Extension) method

Finally, a List is returned with all the extensions available after the discovery process finishes.

Parameters:

classLoader - a not null ClassLoader in which to search for extensions

Returns:

a List with all the available extensions

registerExtension

boolean registerExtension(Extension extension)

Registers the given Extension If a matching Extension is already registered, then this manager will apply whatever policy finds more convenient to decide if the existing registration is kept or replaced. That is up to the implementation. The only thing this contract guarantees is that each extension type will be registered only once and that the discovery process will not fail if many discovery runs are triggered over the same classpath.

Parameters:

extension - the Extension to be registered. Cannot be null

Returns:

true if the extension was registered. false if the platform decided to kept an existing declaration

getExtensions

Set<Extension> getExtensions()

Returns a Set listing all the discovered Extensions.

Returns:

an Set. Will not be null but might be empty

getExtensionsCapableOf

<C> Set<Extension> getExtensionsCapableOf(Class<C> capability)

Returns a Set with the Extensions that have the given capability

Parameters:

capability - a Class representing a capability

Returns:

a Set with the matching Extensions. It might be null but will never be empty

registerConfigurationInstanceProvider

<C> void registerConfigurationInstanceProvider(Extension extension,
                                             String providerName,
                                             ConfigurationInstanceProvider<C> configurationInstanceProvider)

Registers the configurationInstanceProvider. The provider can later be referenced by the given providerName

Type Parameters:

C - the type of the configurations instances that configurationInstanceProvider provides

Parameters:

providerName - the name under which the configurationInstanceProvider will be referenced

configurationInstanceProvider - a ConfigurationInstanceProvider