org.qi4j.api.service.qualifier
Class ServiceQualifier

java.lang.Object
  org.qi4j.api.service.qualifier.ServiceQualifier

public abstract class ServiceQualifier
extends Object

This class helps you select a particular service from a list. Provide a Selector which does the actual selection from the list. A common case is to select based on identity of the service, which you can do this way: new ServiceQualifier(services, ServiceQualifier.withId("someId")) Many selectors can be combined by using firstOf. Example: new ServiceQualifier(services, firstOf(withTags("sometag"), firstActive(), first())) This will pick a service that has the tag "sometag", or if none is found take the first active one. If no service is active, then the first service will be picked.

Constructor Summary

ServiceQualifier()

Method Summary

static <T> T	firstService(Specification<ServiceReference<?>> qualifier, Iterable<ServiceReference<T>> services)
abstract boolean	qualifies(ServiceReference<?> service)
static Specification<ServiceReference<?>>	whereActive()
static Specification<ServiceReference<?>>	whereAvailable()
static Specification<ServiceReference<?>>	whereMetaInfoIs(Object metaInfo)
static Specification<ServiceReference<?>>	withId(String anId)
static Specification<ServiceReference<?>>	withTags(String... tags)

Methods inherited from class java.lang.Object

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

Constructor Detail

ServiceQualifier

public ServiceQualifier()

Method Detail

firstService

public static <T> T firstService(Specification<ServiceReference<?>> qualifier,
                                 Iterable<ServiceReference<T>> services)

withId

public static Specification<ServiceReference<?>> withId(String anId)

whereMetaInfoIs

public static Specification<ServiceReference<?>> whereMetaInfoIs(Object metaInfo)

whereActive

public static Specification<ServiceReference<?>> whereActive()

whereAvailable

public static Specification<ServiceReference<?>> whereAvailable()

withTags

public static Specification<ServiceReference<?>> withTags(String... tags)

qualifies

public abstract boolean qualifies(ServiceReference<?> service)