ch.inftec.ju.ee.cdi

Class DynamicCdiLoader

java.lang.Object

ch.inftec.ju.ee.cdi.DynamicCdiLoader

@ApplicationScoped
public class DynamicCdiLoader
extends Object

Helper class to load CDI implementations dynamically at run time using system properties to configure them.

To 'activate' DynamicCdiLoader in a CDI project, add a new class that extends from it in a beans enabled module.

Implementations to be found by the DynamicCdiLoader must implement the tag interface DynamicCdi. They should implement another interface for the Service they implement (so we can have different implementations at all).

They can optionally define an annotation DynamicCdiTag with a String value. If they do, this implementation will be loaded if the tag is activated.

A tag can be activated either by specify a property with the full class name as its key and the tag as its value or by specifying the default tag using the property ju.ee.cdi.defaultDynamicCdiTag

If no tag is specified, the default value '-' will be used which stands for the default implementation.

Author:

Martin Meyer

Important:Every dynamic implementation has to extend the interface DynamicCdi AND to specify a tag DynamicCdiTag. We need the tag to avoid duplicate declaration issues with weld. When we use a producer to lookup the actual implementation, it will not have a tag thus making the declaration unambiguous.

Constructor Summary

Constructors

Constructor and Description
DynamicCdiLoader()
DynamicCdiLoader(javax.enterprise.inject.Instance<DynamicCdi> dynamicCdis) A Producer of DynamicCdiLoader will need to get Instance injected by Weld using the annotations @Inject @Any

Method Summary

Methods

Modifier and Type	Method and Description
<T> T	getImplementation(Class<T> clazz) Gets the specified implementation for the given class.

Methods inherited from class java.lang.Object

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

Constructor Detail

DynamicCdiLoader

public DynamicCdiLoader()

DynamicCdiLoader

public DynamicCdiLoader(javax.enterprise.inject.Instance<DynamicCdi> dynamicCdis)

A Producer of DynamicCdiLoader will need to get Instance injected by Weld using the annotations @Inject @Any

Parameters:

dynamicCdis -

Method Detail

getImplementation

public <T> T getImplementation(Class<T> clazz)

Gets the specified implementation for the given class.

This method is mainly public so we can test it from the esw-test1 package. Normally, it will not be called from outside.

Parameters:

clazz - Clazz to get implementation for (i.e. CDI instance with the appropriate SimulatorTag)

Returns:

Instance of clazz

Throws:

ServiceDbRuntimeException - If no implementation can be found