Package org.apache.turbine.services
Services are singletons that have pluggable implementation and can participate in Turbine startup and shutdown.
What is a service?
The life cycle of a ServiceA Service (or any other Initable, if we had any) is not supposed to do much in it's constructor. Especialy it should not allocate any costly resources like large memory structures, DB or network connections and the like. It may well happen that the Service is sitting in the config file, but the application does not need it, so allocating all resources at system startup might be a loss. Early initialization is similar to the constructor. It is used to pass some information that the Service will need in it's future operation. UniqueId Service uses the HttpRequest object from the first Turbine invocation to determine URL this instance is runnign under, to generate instance ID. Early initialization method should process the configuration, store some values, but NOT allocate resources. There is still a chance that the Service will not be used. If the Service is ready to work (i.e. does not need any more objects being sent to it), and does not to allocate any resources during late initialization, the internal state can be changed so that getInit() returns true. Late initialization happens when the Service is requested by the application for the first time. It should allocate any resources needed and chnge the state so that getInit() returns true. If getInit() returns false after init() is executed, the Service has malfunctioned. After late initialization, the Service is ready to perform actions on behalf of the application. When the Service is no longer needed (this usually happens when system is shutting down), the shutdown() method is called. shutdown() should deallocate all resources. If any error conditions occur they are ignored. Initialization of services outside of the Turbine servlet
In the case where specific Turbine services are desired outside the
context of the
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$Id$
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Interface Summary Interface Description Initable Classes that implement this interface need initialization before they can work.InitableBroker Classes that implement this interface can act as a broker forInitable
classes.Service Services
areInitables
that have a name, and a set of properties.ServiceBroker Classes that implement this interface can act as a broker forService
classes.ServiceManager Classes that implement this interface can act as a manager forService
classes.TurbineServiceProvider Interface for telling Turbine that the implementation class is an external service provider therefore can be used for looking up services not found by the Turbine implementation. -
Class Summary Class Description BaseInitable This class provides a generic implementation ofInitable
.BaseInitableBroker A generic implementation ofInitableBroker
.BaseService This class is a generic implementation ofService
.BaseServiceBroker A generic implementation of aServiceBroker
which provides: Maintaining service name to class name mapping, allowing pluggable service implementations. ProvidingServices
with a configuration based on system wide configuration mechanism. Integration of TurbineServiceProviders for looking up non-local servicesBaseUnicastRemoteService A base implementation of anUnicastRemoteObject
as a TurbineService
.TurbineBaseService This class provides aService
implementation that Services used in Turbine are required to extend.TurbineServices This is a singleton utility class that acts as a Services broker. -
Exception Summary Exception Description InitializationException Thrown byInitable
class in case of initialization problems.InstantiationException Thrown byInitableBroker
andServiceBroker
classes to indicate problems with instatiation of requested objects.