Package org.apache.tamaya.spi

Interface ServiceContext

All Superinterfaces:

ClassloaderAware

public interface ServiceContext
extends ClassloaderAware

This class models the component that is managing the lifecycle current the services used by the Configuration API.

Field Summary

Fields

Modifier and Type	Field	Description
static boolean	PRIORITY_ANNOTATION_AVAILABLE	True if the Priority annotation class is available on the classpath.

Method Summary

Modifier and Type	Method	Description
static boolean	checkPriorityAnnotation(ClassLoader classLoader)	Checks if the Priority annotation class is on the classpath.
default <T> T	create(Class<T> serviceType)	Factory method to createObject a type, hereby a new instance is created on each access.
<T> T	create(Class<T> serviceType, Supplier<T> supplier)	Factory method to createObject a type, hereby a new instance is created on each access.
static int	getPriority(Object o)	Checks the given instance for a @Priority annotation.
default URL	getResource(String resource)	Loads a resource from the current runtime context.
default Collection<URL>	getResources(String resource)	Loads resources from the current runtime context.
default <T> T	getService(Class<T> serviceType)	Access a service singleton via its type.
<T> T	getService(Class<T> serviceType, Supplier<T> supplier)	Access a service singleton via its type.
default <T> List<T>	getServices(Class<T> serviceType)	Access a createList current services, given its type.
<T> List<T>	getServices(Class<T> serviceType, Supplier<List<T>> supplier)	Access a createList current services, given its type.
default int	ordinal()	Get the ordinal of the ServiceContext.
<T> List<T>	register(Class<T> type, List<T> instances, boolean force)	Registers the given instancea as servicea for the given instance, if no * instance already has been registered.
<T> T	register(Class<T> type, T instance, boolean force)	Registers the given instance as a singleton service for the given instance, if no instance already has been registered.
void	reset()	Resets the current service context, removing all loaded services.

Methods inherited from interface org.apache.tamaya.spi.ClassloaderAware

getClassLoader, init

Field Detail

PRIORITY_ANNOTATION_AVAILABLE

static final boolean PRIORITY_ANNOTATION_AVAILABLE

True if the Priority annotation class is available on the classpath.

Method Detail

checkPriorityAnnotation

static boolean checkPriorityAnnotation(ClassLoader classLoader)

Checks if the Priority annotation class is on the classpath.

Parameters:

classLoader - the target classloader, not null.

Returns:

true, if the annotation is loaded.

ordinal

default int ordinal()

Get the ordinal of the ServiceContext.

Returns:

ordinal of the ServiceContext. The one with the highest ordinal will be taken.

getPriority

static int getPriority(Object o)

Checks the given instance for a @Priority annotation. If present the annotation's value is evaluated. If no such annotation is present, a default priority of 1 is returned.

Parameters:

o - the instance, not null.

Returns:

a priority, by default 1.

getService

default <T> T getService(Class<T> serviceType)

Access a service singleton via its type. If multiple implementations for the very serviceType exist then the one with the highest Priority will be used.

Type Parameters:

T - the type of the service type.

Parameters:

serviceType - the service type.

Returns:

The instance to be used, or null

Throws:

ConfigException - if there are multiple service implementations with the maximum priority.

getService

<T> T getService(Class<T> serviceType,
                 Supplier<T> supplier)

Access a service singleton via its type. If multiple implementations for the very serviceType exist then the one with the highest Priority will be used.

Type Parameters:

T - the type of the service type.

Parameters:

serviceType - the service type.

supplier - the supplier to be used, if no services could be evaluated. If null, an empty collection is returned, when no services could be located.

Returns:

The instance to be used, or null

Throws:

ConfigException - if there are multiple service implementations with the maximum priority.

create

default <T> T create(Class<T> serviceType)

Factory method to createObject a type, hereby a new instance is created on each access. If multiple implementations for the very serviceType exist then the one with the highest Priority will be used as the base for creating subsequent instances.

Type Parameters:

T - the type of the service type.

Parameters:

serviceType - the service type.

Returns:

The new instance to be used, or null

Throws:

ConfigException - if there are multiple service implementations with the maximum priority.

create

<T> T create(Class<T> serviceType,
             Supplier<T> supplier)

Factory method to createObject a type, hereby a new instance is created on each access. If multiple implementations for the very serviceType exist then the one with the highest Priority will be used as the base for creating subsequent instances.

Type Parameters:

T - the type of the service type.

Parameters:

supplier - the supplier to create a new service, if no service could be autodetected.

serviceType - the service type.

Returns:

The new instance to be used, or null

Throws:

ConfigException - if there are multiple service implementations with the maximum priority.

getServices

default <T> List<T> getServices(Class<T> serviceType)

Access a createList current services, given its type. The bootstrap mechanism should order the instance for precedence, hereby the most significant should be first in order.

Type Parameters:

T - the type of the createList element returned by this method

Parameters:

serviceType - the service type.

Returns:

The instance to be used, never null

getServices

<T> List<T> getServices(Class<T> serviceType,
                        Supplier<List<T>> supplier)

Access a createList current services, given its type. The bootstrap mechanism should order the instance for precedence, hereby the most significant should be first in order. If no instances could be found, the instances supplied by the supplier given are registered and used.

Type Parameters:

T - the type of the createList element returned by this method

Parameters:

serviceType - the service type.

supplier - the supplier to be used, if no services could be evaluated. If null, an empty collection is returned, when no services could be located.

Returns:

The instance to be used, never null

getResources

default Collection<URL> getResources(String resource)

Loads resources from the current runtime context. This method allows to use runtime specific code to load resources, e.g. within OSGI environments.

Parameters:

resource - the resource, not null.

Returns:

the resources found

getResource

default URL getResource(String resource)

Loads a resource from the current runtime context. This method allows to use runtime specific code to load a resource, e.g. within OSGI environments.

Parameters:

resource - the resource, not null.

Returns:

the resource found, or null.

register

<T> T register(Class<T> type,
               T instance,
               boolean force)

Registers the given instance as a singleton service for the given instance, if no instance already has been registered.

Type Parameters:

T - thy type.

Parameters:

type - the type to register, not null.

instance - the instance, not null.

force - if true, any existing instance will be replaced.

Returns:

the instance registered or already present.

register

<T> List<T> register(Class<T> type,
                     List<T> instances,
                     boolean force)

Registers the given instancea as servicea for the given instance, if no * instance already has been registered.

Type Parameters:

T - thy type.

Parameters:

type - the type to register, not null.

instances - the instancea, not null.

force - if true, any existing instances will be replaced.

Returns:

the instances registered or already present.

reset

void reset()

Resets the current service context, removing all loaded services. This implicitly triggers a new load of the service context.