org.tentackle.common

Interface ServiceFinder

All Known Implementing Classes:

DefaultServiceFinder

public interface ServiceFinder

Finds service configurations.

Very similar to ServiceLoader but provides additional methods to load configurations without being forced to load the classes.
Furthermore, it is not restricted to META-INF/services and the contents of the configuration file. Supports dedicated classloaders for services as well.

Applications should use the ServiceFactory to allow replacement of the finder (see Service-annotation)

Author:

harald

Method Summary

Modifier and Type	Method and Description
Map<String,String>	createNameMap(String serviceName) Creates a map of names to mapped services.
Map<String,Set<String>>	createNameMapToAll(String serviceName) Creates a map of names to all mapped services.
Map.Entry<String,URL>	findFirstServiceConfiguration(String serviceName) Finds the first service configurations by service name. If similar configurations appear more than once on the classpath, the first is returned.
<T> Class<T>	findFirstServiceProvider(Class<T> service) Finds the first service provider by service name. If similar configurations appear more than once on the classpath, the first is returned.
Map<String,URL>	findServiceConfigurations(String serviceName) Finds service configurations by service name. Iterations over the returned map are ordered by discovery along the classpath.
<T> Collection<Class<T>>	findServiceProviders(Class<T> service) Finds the service providers by service names.
Enumeration<URL>	findServiceURLs(String serviceName) Finds URLs of a service by name.
Map.Entry<String,URL>	findUniqueServiceConfiguration(String serviceName) Finds a unique service configurations by service name. It is checked that the service is defined exactly once.
<T> Class<T>	findUniqueServiceProvider(Class<T> service) Finds the unique service provider by service name.
ClassLoader	getClassLoader() Gets the default classloader used by this finder.
String	getServicePath() Gets the finder' service path it is responsible for.

Method Detail

getClassLoader

ClassLoader getClassLoader()

Gets the default classloader used by this finder.

Returns:

the classloader, never null

getServicePath

String getServicePath()

Gets the finder' service path it is responsible for.

Returns:

the service path

findFirstServiceConfiguration

Map.Entry<String,URL> findFirstServiceConfiguration(String serviceName)

Finds the first service configurations by service name.
If similar configurations appear more than once on the classpath, the first is returned. Useful to override service default implementations.

Parameters:

serviceName - the service name, usually a classname

Returns:

the service configuation entry, never null

Throws:

TentackleRuntimeException - if no such service found

findFirstServiceProvider

<T> Class<T> findFirstServiceProvider(Class<T> service)
                               throws ClassNotFoundException

Finds the first service provider by service name.
If similar configurations appear more than once on the classpath, the first is returned. Useful to override service default implementations.

Type Parameters:

T - the service type

Parameters:

service - the service class

Returns:

the provider class

Throws:

ClassNotFoundException - if some provider could not be loaded

findServiceConfigurations

Map<String,URL> findServiceConfigurations(String serviceName)

Finds service configurations by service name.
Iterations over the returned map are ordered by discovery along the classpath.

Parameters:

serviceName - the service name, usually a classname

Returns:

a map of the configured services and their corresponding URLs

findServiceProviders

<T> Collection<Class<T>> findServiceProviders(Class<T> service)
                                       throws ClassNotFoundException

Finds the service providers by service names.

Type Parameters:

T - the service type

Parameters:

service - the service class

Returns:

the classes providing this service

Throws:

ClassNotFoundException - if some provider could not be loaded

findServiceURLs

Enumeration<URL> findServiceURLs(String serviceName)

Finds URLs of a service by name.

Parameters:

serviceName - the service name, usually a classname

Returns:

the service's resource urls

findUniqueServiceConfiguration

Map.Entry<String,URL> findUniqueServiceConfiguration(String serviceName)

Finds a unique service configurations by service name.
It is checked that the service is defined exactly once. Useful for factories, singletons and alike.

Parameters:

serviceName - the service name, usually a classname

Returns:

the service configuation entry

findUniqueServiceProvider

<T> Class<T> findUniqueServiceProvider(Class<T> service)
                                throws ClassNotFoundException

Finds the unique service provider by service name.

Type Parameters:

T - the service type

Parameters:

service - the service class

Returns:

the provider class

Throws:

ClassNotFoundException - if some provider could not be loaded

createNameMap

Map<String,String> createNameMap(String serviceName)

Creates a map of names to mapped services.

They key of the map is the service name. The value is the name providing the service which comes first in the classpath.

Parameters:

serviceName - the service class

Returns:

the map

createNameMapToAll

Map<String,Set<String>> createNameMapToAll(String serviceName)

Creates a map of names to all mapped services.

They key of the map is the service name. The value is a list of names providing the service ordered by discovery along the classpath.

Parameters:

serviceName - the service class

Returns:

the map