org.apache.polygene.api.service

Interface ServiceFinder

All Known Subinterfaces:

Module, ModuleSpi

public interface ServiceFinder

Interface used to query for ServiceReferences.

Each ServiceFinder is obtained from a specific Module, and the lookup rules are the following:

1. First look in the same Module as the ServiceFinder
2. Then look in the same Layer as the ServiceFinder. Any Services declared with Visibility Layer and Application should be included
3. Then look in the used Layers. Any Services declared with Visibility Application should be included

Both native Polygene services and imported services are considered, with preference to native services.

Method Summary

Modifier and Type	Method and Description
<T> ServiceReference<T>	findService(Class<T> serviceType) Find a ServiceReference that implements the given type.
<T> ServiceReference<T>	findService(Type serviceType) Find a ServiceReference that implements the given type.
<T> Stream<ServiceReference<T>>	findServices(Class<T> serviceType) Find ServiceReferences that implements the given type.
<T> Stream<ServiceReference<T>>	findServices(Type serviceType) Find ServiceReferences that implements the given type.

Method Detail

findService

<T> ServiceReference<T> findService(Class<T> serviceType)
                             throws NoSuchServiceTypeException

Find a ServiceReference that implements the given type.

Type Parameters:

T - Service type

Parameters:

serviceType - the type that the Service must implement

Returns:

a ServiceReference if one is found

Throws:

NoSuchServiceTypeException - if no service of serviceType is found

findService

<T> ServiceReference<T> findService(Type serviceType)
                             throws NoSuchServiceTypeException

Find a ServiceReference that implements the given type.

Type Parameters:

T - Service type

Parameters:

serviceType - the type that the Service must implement

Returns:

a ServiceReference if one is found

Throws:

NoSuchServiceTypeException - if no service of serviceType is found

findServices

<T> Stream<ServiceReference<T>> findServices(Class<T> serviceType)

Find ServiceReferences that implements the given type.

The order of the references is such that Services more local to the querying Module is earlier in the list.

Type Parameters:

T - Service type

Parameters:

serviceType - the type that the Services must implement

Returns:

a stream of ServiceReferences for the given type. It is empty if none exist

findServices

<T> Stream<ServiceReference<T>> findServices(Type serviceType)

Find ServiceReferences that implements the given type.

The order of the references is such that Services more local to the querying Module is earlier in the list.

Type Parameters:

T - Service type

Parameters:

serviceType - the type that the Services must implement

Returns:

a stream of ServiceReferences for the given type. It is empty if none exist