Package org.apache.turbine.services

Class BaseServiceBroker

java.lang.Object

org.apache.turbine.services.BaseServiceBroker

All Implemented Interfaces:

ServiceBroker

Direct Known Subclasses:

TurbineServices

public abstract class BaseServiceBroker
extends Object
implements ServiceBroker

A generic implementation of a ServiceBroker which provides:

• Maintaining service name to class name mapping, allowing pluggable service implementations.
• Providing Services with a configuration based on system wide configuration mechanism.
• Integration of TurbineServiceProviders for looking up non-local services

Version:

$Id$

Author:

Kevin Burton, Rafal Krzewski, Daniel Rall, Jason van Zyl, Martin Poeschl, Henning P. Schmiedehausen

Field Summary

Fields

Modifier and Type	Field	Description
static String	CLASSNAME_SUFFIX	A Service property determining its implementing class name .
static String	SERVICE_PREFIX	A prefix for Service properties in TurbineResource.properties.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BaseServiceBroker()	Default constructor, protected as to only be usable by subclasses.

Method Summary

Modifier and Type	Method	Description
String	getApplicationRoot()	Get the application root as set by the parent application.
org.apache.commons.configuration2.Configuration	getConfiguration()	Get the configuration for this service manager.
org.apache.commons.configuration2.Configuration	getConfiguration(String name)	Returns the configuration for the specified service.
protected Object	getNonLocalService(String name)	Get a non-local service managed by a TurbineServiceProvider.
Object	getService(String name)	Returns an instance of requested Service.
protected Service	getServiceInstance(String name)	Retrieves an instance of a Service without triggering late initialization.
Iterator<String>	getServiceNames()	Returns an Iterator over all known service names.
Iterator<String>	getServiceNames(String prefix)	Returns an Iterator over all known service names beginning with the provided prefix.
Object	getServiceObject(String name)	Get an application specific service object.
void	init()	Initialize this service manager.
protected void	initMapping()	Creates a mapping between Service names and class names.
void	initService(String name)	Performs early initialization of specified service.
void	initServices()	Performs early initialization of all services.
void	initServices(boolean report)	Performs early initialization of all services.
protected boolean	isLocalService(String name)	Determines if the requested service is managed by this ServiceBroker.
protected boolean	isNonLocalService(String name)	Determines if the requested service is managed by an initialized TurbineServiceProvider.
boolean	isRegistered(String serviceName)	Determines whether a service is registered in the configured TurbineResources.properties.
void	setApplicationRoot(String applicationRoot)	Set the application root.
void	setConfiguration(org.apache.commons.configuration2.Configuration configuration)	Set the configuration object for the services broker.
void	setServiceObject(String name, Object value)	Set an application specific service object that can be used by application specific services.
void	shutdownService(String name)	Shuts down a Service, releasing resources allocated by an Service, and returns it to its initial (uninitialized) state.
void	shutdownServices()	Shuts down all Turbine services, releasing allocated resources and returning them to their initial (uninitialized) state.

Methods inherited from class java.lang.Object

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

Field Detail

SERVICE_PREFIX

public static final String SERVICE_PREFIX

A prefix for Service properties in TurbineResource.properties.

See Also:

Constant Field Values

CLASSNAME_SUFFIX

public static final String CLASSNAME_SUFFIX

A Service property determining its implementing class name .

See Also:

Constant Field Values

Constructor Detail

BaseServiceBroker

protected BaseServiceBroker()

Default constructor, protected as to only be usable by subclasses. This constructor does nothing.

Method Detail

setConfiguration

public void setConfiguration(org.apache.commons.configuration2.Configuration configuration)

Set the configuration object for the services broker. This is the configuration that contains information about all services in the care of this service manager.

Parameters:

configuration - Broker configuration.

getConfiguration

public org.apache.commons.configuration2.Configuration getConfiguration()

Get the configuration for this service manager.

Returns:

Broker configuration.

init

public void init()
          throws InitializationException

Initialize this service manager.

Throws:

InitializationException - if the initialization fails

setServiceObject

public void setServiceObject(String name,
                             Object value)

Set an application specific service object that can be used by application specific services.

Parameters:

name - name of service object

value - value of service object

getServiceObject

public Object getServiceObject(String name)

Get an application specific service object.

Parameters:

name - the name of the service object

Returns:

Object application specific service object

initMapping

protected void initMapping()
                    throws InitializationException

Creates a mapping between Service names and class names. The mapping is built according to settings present in TurbineResources.properties. The entries should have the following form:

 services.MyService.classname=com.mycompany.MyServiceImpl
 services.MyOtherService.classname=com.mycompany.MyOtherServiceImpl
 

Generic ServiceBroker provides no Services.

Throws:

InitializationException - if a service class could not be found

isRegistered

public boolean isRegistered(String serviceName)

Determines whether a service is registered in the configured TurbineResources.properties.

Specified by:

isRegistered in interface ServiceBroker

Parameters:

serviceName - The name of the service whose existence to check.

Returns:

Registration predicate for the desired services.

getServiceNames

public Iterator<String> getServiceNames()

Returns an Iterator over all known service names.

Returns:

An Iterator of service names.

getServiceNames

public Iterator<String> getServiceNames(String prefix)

Returns an Iterator over all known service names beginning with the provided prefix.

Parameters:

prefix - The prefix against which to test.

Returns:

An Iterator of service names which match the prefix.

initService

public void initService(String name)
                 throws InitializationException

Performs early initialization of specified service.

Specified by:

initService in interface ServiceBroker

Parameters:

name - The name of the service (generally the SERVICE_NAME constant of the service's interface definition).

Throws:

InitializationException - Initialization of this service was not successful.

initServices

public void initServices()

Performs early initialization of all services. Failed early initialization of a Service may be non-fatal to the system, thus any exceptions are logged and the initialization process continues.

initServices

public void initServices(boolean report)
                  throws InstantiationException,
                         InitializationException

Performs early initialization of all services. You can decide to handle failed initializations if you wish, but then after one service fails, the other will not have the chance to initialize.

Parameters:

report - true if you want exceptions thrown.

Throws:

InstantiationException - if the service could not be instantiated

InitializationException - if the service could not be initialized

shutdownService

public void shutdownService(String name)

Shuts down a Service, releasing resources allocated by an Service, and returns it to its initial (uninitialized) state.

Specified by:

shutdownService in interface ServiceBroker

Parameters:

name - The name of the Service to be uninitialized.

shutdownServices

public void shutdownServices()

Shuts down all Turbine services, releasing allocated resources and returning them to their initial (uninitialized) state.

Specified by:

shutdownServices in interface ServiceBroker

getService

public Object getService(String name)
                  throws InstantiationException

Returns an instance of requested Service.

Specified by:

getService in interface ServiceBroker

Parameters:

name - The name of the Service requested.

Returns:

An instance of requested Service.

Throws:

InstantiationException - if the service is unknown or can't be initialized.

getServiceInstance

protected Service getServiceInstance(String name)
                              throws InstantiationException

Retrieves an instance of a Service without triggering late initialization. Early initialization of a Service can require access to Service properties. The Service must have its name and serviceBroker set by then. Therefore, before calling Initable.initClass(Object), the class must be instantiated with InitableBroker.getInitableInstance(), and Service.setServiceBroker() and Service.setName() must be called. This calls for two - level accessing the Services instances.

Parameters:

name - The name of the service requested.

Returns:

the Service instance

Throws:

InstantiationException - The service is unknown or can't be initialized.

getConfiguration

public org.apache.commons.configuration2.Configuration getConfiguration(String name)

Returns the configuration for the specified service.

Specified by:

getConfiguration in interface ServiceBroker

Parameters:

name - The name of the service.

Returns:

Configuration of requested Service.

setApplicationRoot

public void setApplicationRoot(String applicationRoot)

Set the application root.

Parameters:

applicationRoot - application root

getApplicationRoot

public String getApplicationRoot()

Get the application root as set by the parent application.

Specified by:

getApplicationRoot in interface ServiceBroker

Returns:

String application root

isLocalService

protected boolean isLocalService(String name)

Determines if the requested service is managed by this ServiceBroker.

Parameters:

name - The name of the Service requested.

Returns:

true if the service is managed by the this ServiceBroker

isNonLocalService

protected boolean isNonLocalService(String name)

Determines if the requested service is managed by an initialized TurbineServiceProvider. We use the service names to lookup the TurbineServiceProvider to ensure that we get a fully initialized service.

Parameters:

name - The name of the Service requested.

Returns:

true if the service is managed by a TurbineServiceProvider

getNonLocalService

protected Object getNonLocalService(String name)
                             throws InstantiationException

Get a non-local service managed by a TurbineServiceProvider.

Parameters:

name - The name of the Service requested.

Returns:

the requested service

Throws:

InstantiationException - the service couldn't be instantiated