org.apache.hivemind.impl
Class ServicePointImpl

java.lang.Object
  org.apache.hivemind.impl.BaseLocatable
      org.apache.hivemind.impl.AbstractExtensionPoint
          org.apache.hivemind.impl.ServicePointImpl

All Implemented Interfaces:

ConstructableServicePoint, ExtensionPoint, ServicePoint, Locatable, LocationHolder

public final class ServicePointImpl
extends AbstractExtensionPoint
implements ConstructableServicePoint

Abstract implementation of ServicePoint. Provides some of the machinery for creating new service instances, delegating most of it to the ServiceModel instace for the service.

Author:

Howard Lewis Ship

Constructor Summary

ServicePointImpl(Module module, ServicePointDefinition definition)

Method Summary

void	addRegistryShutdownListener(RegistryShutdownListener listener) Adds a shutdown listener; HiveMind uses two coordinators; the first is the hivemind.ShutdownCoordinator service, which is the coordinator used for service implementations.
void	clearConstructorInformation() Invoked by the ServiceModel when constuction information (the builder and interceptors) is no longer needed.
protected void	extendDescription(ToStringBuilder builder) Implemented in subclasses to provide details about subclass properties.
void	forceServiceInstantiation() Forces the service into existence.
java.lang.Class	getDeclaredInterface() Returns the interface for the service as specified in the descriptor; starting with release 1.1 it is possible to define a service in terms of a class (as the interface).
ImplementationDefinition	getImplementationDefinition()
java.util.List	getOrderedInterceptorContributions() Returns a list of InterceptorConstructors, ordered according to their dependencies.
java.lang.Object	getService(java.lang.Class serviceInterface) Obtains the full service implementation for this service extension point, an object that implements the service interface.
ImplementationConstructor	getServiceConstructor() Returns the service constructor.
java.lang.Class	getServiceInterface() Returns the type of the service, the interface the service implements.
java.lang.String	getServiceInterfaceClassName() Returns the fully qualified class name of the service interface.
java.lang.String	getServiceModel()
ServicePointDefinition	getServicePointDefinition()
void	setShutdownCoordinator(ShutdownCoordinator coordinator)

Methods inherited from class org.apache.hivemind.impl.AbstractExtensionPoint

getDefinition, getErrorLog, getExtensionPointId, getLocation, getLog, getModule, getVisibility, toString, visibleToModule

Methods inherited from class org.apache.hivemind.impl.BaseLocatable

setLocation

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hivemind.internal.ExtensionPoint

getErrorLog, getExtensionPointId, getLog, getModule, visibleToModule

Methods inherited from interface org.apache.hivemind.Locatable

getLocation

Constructor Detail

ServicePointImpl

public ServicePointImpl(Module module,
                        ServicePointDefinition definition)

Method Detail

extendDescription

protected void extendDescription(ToStringBuilder builder)

Description copied from class: AbstractExtensionPoint

Implemented in subclasses to provide details about subclass properties.

Specified by:

extendDescription in class AbstractExtensionPoint

getServiceInterface

public java.lang.Class getServiceInterface()

Description copied from interface: ServicePoint

Returns the type of the service, the interface the service implements. This may be a synthetic interface when the interface for the service point is, in fact, a class. It equals the class returned by ServicePoint.getDeclaredInterface() if the declared interface is a real interface and not a class.

Specified by:

getServiceInterface in interface ServicePoint

getDeclaredInterface

public java.lang.Class getDeclaredInterface()

Description copied from interface: ServicePoint

Returns the interface for the service as specified in the descriptor; starting with release 1.1 it is possible to define a service in terms of a class (as the interface). In that case the POJO class is returned here.

Specified by:

getDeclaredInterface in interface ServicePoint

getServiceInterfaceClassName

public java.lang.String getServiceInterfaceClassName()

Description copied from interface: ServicePoint

Returns the fully qualified class name of the service interface. This is useful so that loading the actual service interface class can be deferred as late as possible. This is the value, as specified in the descriptor (except that simple names in the descriptor are prefixed with the module's package name). Starting in release 1.1, this may be the name of a ordinary class, not an interface.

Specified by:

getServiceInterfaceClassName in interface ServicePoint

getService

public java.lang.Object getService(java.lang.Class serviceInterface)

Description copied from interface: ServicePoint

Obtains the full service implementation for this service extension point, an object that implements the service interface. Because of the different service models, and because of the possibility of interceptors, the exact class and object returned can't be specified (and may vary at different times), but that is not relevant to client code, which is assured that it can invoke the service methods defined by the service interface.

Specified by:

getService in interface ServicePoint

Parameters:

serviceInterface - the class that the service will be cast to; a check is made that the service is assignable to the indicated interface. It does not have to, necessarily, match the service interface (it could be a super-interface, for example).

Returns:

the outermost interceptor for the service, or the core implementation if there are no interceptors.

getServiceModel

public java.lang.String getServiceModel()

clearConstructorInformation

public void clearConstructorInformation()

Description copied from interface: ConstructableServicePoint

Invoked by the ServiceModel when constuction information (the builder and interceptors) is no longer needed.

Specified by:

clearConstructorInformation in interface ConstructableServicePoint

getOrderedInterceptorContributions

public java.util.List getOrderedInterceptorContributions()

Description copied from interface: ConstructableServicePoint

Returns a list of InterceptorConstructors, ordered according to their dependencies. May return null or an empty list.

Note that the order is tricky! To keep any error messages while ordering the interceptors understandable, they are ordered according into runtime execution order. Example: If we want a logging interceptor to operate before a security-check interceptor, we'll write the following in the descriptor:

               <interceptor service-id="hivemind.LoggingInterceptor" before="*"/>
               <interceptor service-id="somepackage.SecurityInterceptor"/>
 

The before value for the first interceptor contribution will be assigned to the contribution's followingNames property, because all other interceptors (including the security interceptor) should have their behavior follow the logging interceptor.

To get this behavior, the logging interceptor will delegate to the security interceptor, and the security interceptor will delegate to the core service implementation.

The trick is that interceptors are applied in reverse order: we start with core service implementation, wrap it with the security interceptor, then wrap that with the logging interceptor ... but that's an issue that applies when building the interceptor stack around the core service implementation.

Specified by:

getOrderedInterceptorContributions in interface ConstructableServicePoint

Returns:

Ordered list of InterceptorDefinitions

setShutdownCoordinator

public void setShutdownCoordinator(ShutdownCoordinator coordinator)

addRegistryShutdownListener

public void addRegistryShutdownListener(RegistryShutdownListener listener)

Description copied from interface: ConstructableServicePoint

Adds a shutdown listener; HiveMind uses two coordinators; the first is the hivemind.ShutdownCoordinator service, which is the coordinator used for service implementations. The second coordinator is used by the HiveMind infrastructure directly; this method adds a listener to that coordinator. Why two? It's about order of operations during registry shutdown; the hivemind.ShutdownCoordinator service's listeners are all invoked first, the the internal coordinator, to shutdown proxies and the like. This allows services to communicate during shutdown.

Specified by:

addRegistryShutdownListener in interface ConstructableServicePoint

Parameters:

listener - the listener to be added to the infrastructure's shutdown coordinator

forceServiceInstantiation

public void forceServiceInstantiation()

Forces the service into existence.

Specified by:

forceServiceInstantiation in interface ServicePoint

getServiceConstructor

public ImplementationConstructor getServiceConstructor()

Returns the service constructor.

Specified by:

getServiceConstructor in interface ConstructableServicePoint

getImplementationDefinition

public ImplementationDefinition getImplementationDefinition()

Specified by:

getImplementationDefinition in interface ConstructableServicePoint

getServicePointDefinition

public ServicePointDefinition getServicePointDefinition()

Specified by:

getServicePointDefinition in interface ServicePoint

Returns:

the service point definition that describes this service point