org.apache.polygene.api.service.qualifier

Class ServiceQualifier

java.lang.Object

org.apache.polygene.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 reference of the service, which you can do this way:

 new ServiceQualifier<MyService>(services, ServiceQualifier.withId("someId"))
 

Many selectors can be combined by using firstOf. Example:

 new ServiceQualifier<MyService>(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

Constructors

Constructor and Description
ServiceQualifier()

Method Summary

Modifier and Type	Method and Description
static Predicate<ServiceReference<?>>	whereActive()
static Predicate<ServiceReference<?>>	whereAvailable()
static Predicate<ServiceReference<?>>	whereMetaInfoIs(Object metaInfo)
static Predicate<ServiceReference<?>>	withId(String anId)
static Predicate<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

withId

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

whereMetaInfoIs

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

whereActive

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

whereAvailable

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

withTags

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