org.tentackle.common

Class ServiceFactory

java.lang.Object

org.tentackle.common.ServiceFactory

public class ServiceFactory
extends Object

Factory for services based on ServiceFinder.

The factory itself is loaded via the standard JDK ServiceLoader and can be replaced via META-INF/services. If no such configuration is found, for whatever reason, an instance of ServiceFactory is used. As a consequence, the fallback and default implementation is ServiceFactory itself. However, applications can replace it, if necessary.

Author:

harald

Field Summary

Fields

Modifier and Type	Field and Description
static ServiceFactory	INSTANCE the singleton instance.

Constructor Summary

Constructors

Constructor and Description
ServiceFactory() Creates the factory.

Method Summary

Modifier and Type	Method and Description
static void	addExplicitClassLoader(String servicePath, String serviceName, ClassLoader classLoader) Adds an explict classloader for a given service path and name. Loaders are kept in a linked list for each path and name combination.
protected void	addExplicitClassLoaderImpl(String servicePath, String serviceName, ClassLoader classLoader) Adds an explict classloader for a given service path and name. Loaders are kept in a linked list for each path and name combination.
static void	applyResourceIndex(ClassLoader classLoader, String indexName, boolean set) Apply a given resource index. The index is usually created via the tentackle-maven-plugin's analyze goal with the index option set to something like "META-INF/RESOURCES-INDEX.LIST".
protected void	applyResourceIndexImpl(ClassLoader classLoader, String indexName, boolean set) Apply a given resource index. The index is usually created via the tentackle-maven-plugin's analyze goal with the index option set to something like "META-INF/RESOURCES-INDEX.LIST".
static <T> T	createService(Class<T> serviceClass) Utility method to create a service instance. This is the standard way to instantiate singletons.
static <T> T	createService(Class<T> serviceClass, Class<? extends T> defaultClass) Utility method to create a service instance with a default if not found.
static <T> Class<T>	createServiceClass(Class<T> serviceClass) Utility method to create a service instance. This is the standard way to instantiate singletons.
protected ClassLoader	getClassLoader() Gets the default classloader. The classloader to use is determined as follows: use the fixed classloader set by setFixedClassLoader(java.lang.ClassLoader), if not null else try Thread.currentThread().getContextClassLoader() if the context classloader is null, use the classloader that loaded the service factory
static ClassLoader	getClassLoader(String servicePath, String serviceName) Gets the classloader for a given service path and name. If an explicit classloader is set, the last defined classloader for the given path and name is returned.
protected ClassLoader	getClassLoaderImpl(String servicePath, String serviceName) Gets the classloader for a given service path and name. If an explicit classloader is set, the last defined classloader for the given path and name is returned.
static ClassLoader	getExplicitClassLoader(String servicePath, String serviceName) Gets the explicit classloader for a given service path and name.
protected ClassLoader	getExplicitClassLoaderImpl(String servicePath, String serviceName) Gets the explicit classloader for a given service path and name.
Map<ServiceFinderKey,ServiceFinder>	getFinderMap() Gets the finder map. Allows applications to modify or add finders programmatically. The map is threadsafe.
ClassLoader	getFixedClassLoader() Gets the fixed classloader.
static ServiceFinder	getServiceFinder() Gets a service finder. If the finder does not exist yet, it will be created.
static ServiceFinder	getServiceFinder(ClassLoader loader, String servicePath) Gets a service finder for a given classloader and service path. If the finder does not exist yet, it will be created.
static ServiceFinder	getServiceFinder(String servicePath) Gets a service finder for a given service path. If the finder does not exist yet, it will be created.
protected Class<? extends ServiceFinder>	getServiceFinderClass() Gets the class of the service finder.
protected ServiceFinder	getServiceFinderImpl() Gets a service finder. If the finder does not exist yet, it will be created.
protected ServiceFinder	getServiceFinderImpl(ClassLoader loader, String servicePath) Gets a service finder for a given classloader and service path. If the finder does not exist yet, it will be created.
protected ServiceFinder	getServiceFinderImpl(String servicePath) Gets a service finder for a given service path. If the finder does not exist yet, it will be created.
static void	removeExplicitClassLoader(String servicePath, String serviceName, ClassLoader classLoader) Remove]s an explict classloader for a given service path and name. Loaders are kept in a linked list for each path and name combination.
protected void	removeExplicitClassLoaderImpl(String servicePath, String serviceName, ClassLoader classLoader) Remove]s an explict classloader for a given service path and name. Loaders are kept in a linked list for each path and name combination.
void	setFixedClassLoader(ClassLoader classLoader) Sets the fixed classloader. Default is Thread.currentThread().getContextClassLoader().

Methods inherited from class java.lang.Object

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

Field Detail

INSTANCE

public static final ServiceFactory INSTANCE

the singleton instance.

Constructor Detail

ServiceFactory

public ServiceFactory()

Creates the factory.

Method Detail

getServiceFinder

public static ServiceFinder getServiceFinder(ClassLoader loader,
                                             String servicePath)

Gets a service finder for a given classloader and service path.
If the finder does not exist yet, it will be created.

Parameters:

loader - the classloader

servicePath - the service path prefix

Returns:

the finder

getServiceFinder

public static ServiceFinder getServiceFinder(String servicePath)

Gets a service finder for a given service path.
If the finder does not exist yet, it will be created. The classloader used is Thread.currentThread().getContextClassLoader().

Parameters:

servicePath - the service path prefix

Returns:

the finder, never null

getServiceFinder

public static ServiceFinder getServiceFinder()

Gets a service finder.
If the finder does not exist yet, it will be created. The classloader used is Thread.currentThread().getContextClassLoader() and the service path is "META_INF/services/".

Returns:

the finder

createServiceClass

public static <T> Class<T> createServiceClass(Class<T> serviceClass)

Utility method to create a service instance.
This is the standard way to instantiate singletons. Finds the first service implementation along the classpath.

Type Parameters:

T - the service type

Parameters:

serviceClass - the service class

Returns:

an instance of the service

createService

public static <T> T createService(Class<T> serviceClass)

Utility method to create a service instance.
This is the standard way to instantiate singletons. Finds the first service implementation along the classpath.

Type Parameters:

T - the service type

Parameters:

serviceClass - the service class

Returns:

an instance of the service

createService

public static <T> T createService(Class<T> serviceClass,
                                  Class<? extends T> defaultClass)

Utility method to create a service instance with a default if not found.

Type Parameters:

T - the service type

Parameters:

serviceClass - the service class

defaultClass - the default class if no service found

Returns:

an instance of the service

getClassLoader

public static ClassLoader getClassLoader(String servicePath,
                                         String serviceName)

Gets the classloader for a given service path and name.
If an explicit classloader is set, the last defined classloader for the given path and name is returned. Otherwise the default classloader is returned.

Parameters:

servicePath - the service path

serviceName - the service name

Returns:

the classloader, never null

getExplicitClassLoader

public static ClassLoader getExplicitClassLoader(String servicePath,
                                                 String serviceName)

Gets the explicit classloader for a given service path and name.

Parameters:

servicePath - the service path

serviceName - the service name

Returns:

the classloader, null if no explicit classloader set

addExplicitClassLoader

public static void addExplicitClassLoader(String servicePath,
                                          String serviceName,
                                          ClassLoader classLoader)

Adds an explict classloader for a given service path and name.
Loaders are kept in a linked list for each path and name combination. Setting a classloader performs a push, clearing a pop. Thus, removing a loader activates the previously set loader, if any. This allows activation and deactivation as it used in OSGi, for example.

Parameters:

servicePath - the service path

serviceName - the service name

classLoader - the classloader, null if remove

removeExplicitClassLoader

public static void removeExplicitClassLoader(String servicePath,
                                             String serviceName,
                                             ClassLoader classLoader)

Remove]s an explict classloader for a given service path and name.
Loaders are kept in a linked list for each path and name combination. Setting a classloader performs a push, clearing a pop. Thus, removing a loader activates the previously set loader, if any. This allows activation and deactivation as it used in OSGi, for example.

Parameters:

servicePath - the service path

serviceName - the service name

classLoader - the classloader, null if remove

applyResourceIndex

public static void applyResourceIndex(ClassLoader classLoader,
                                      String indexName,
                                      boolean set)

Apply a given resource index.
The index is usually created via the tentackle-maven-plugin's analyze goal with the index option set to something like "META-INF/RESOURCES-INDEX.LIST".

This is a utility method, that can be used during the activation within an OSGI-bundle, for example.

Parameters:

classLoader - the classloader to load the index resource

indexName - the name of the index resource

set - true if set loaders, else remove loaders from the services index

getFixedClassLoader

public ClassLoader getFixedClassLoader()

Gets the fixed classloader.

Returns:

the classloader, null if default

setFixedClassLoader

public void setFixedClassLoader(ClassLoader classLoader)

Sets the fixed classloader.
Default is Thread.currentThread().getContextClassLoader().

Parameters:

classLoader - the classloader, null if default

getClassLoader

protected ClassLoader getClassLoader()

Gets the default classloader.
The classloader to use is determined as follows:

1. use the fixed classloader set by setFixedClassLoader(java.lang.ClassLoader), if not null
2. else try Thread.currentThread().getContextClassLoader()
3. if the context classloader is null, use the classloader that loaded the service factory

Returns:

the loader, never null

getClassLoaderImpl

protected ClassLoader getClassLoaderImpl(String servicePath,
                                         String serviceName)

Gets the classloader for a given service path and name.
If an explicit classloader is set, the last defined classloader for the given path and name is returned. Otherwise the default classloader is returned.

Parameters:

servicePath - the service path

serviceName - the service name

Returns:

the classloader, never null

getExplicitClassLoaderImpl

protected ClassLoader getExplicitClassLoaderImpl(String servicePath,
                                                 String serviceName)

Gets the explicit classloader for a given service path and name.

Parameters:

servicePath - the service path

serviceName - the service name

Returns:

the classloader, null if no explicit classloader set

addExplicitClassLoaderImpl

protected void addExplicitClassLoaderImpl(String servicePath,
                                          String serviceName,
                                          ClassLoader classLoader)

Adds an explict classloader for a given service path and name.
Loaders are kept in a linked list for each path and name combination. Setting a classloader performs a push, clearing a pop. Thus, removing a loader activates the previously set loader, if any. This allows activation and deactivation as it used in OSGi, for example.

Parameters:

servicePath - the service path

serviceName - the service name

classLoader - the classloader, null if remove

removeExplicitClassLoaderImpl

protected void removeExplicitClassLoaderImpl(String servicePath,
                                             String serviceName,
                                             ClassLoader classLoader)

Remove]s an explict classloader for a given service path and name.
Loaders are kept in a linked list for each path and name combination. Setting a classloader performs a push, clearing a pop. Thus, removing a loader activates the previously set loader, if any. This allows activation and deactivation as it used in OSGi, for example.

Parameters:

servicePath - the service path

serviceName - the service name

classLoader - the classloader, null if remove

applyResourceIndexImpl

protected void applyResourceIndexImpl(ClassLoader classLoader,
                                      String indexName,
                                      boolean set)

Apply a given resource index.
The index is usually created via the tentackle-maven-plugin's analyze goal with the index option set to something like "META-INF/RESOURCES-INDEX.LIST".

This is a utility method, that can be used during the activation within an OSGI-bundle, for example.

Parameters:

classLoader - the classloader to load the index resource

indexName - the name of the index resource

set - true if set loaders, else remove loaders from the services index

getFinderMap

public Map<ServiceFinderKey,ServiceFinder> getFinderMap()

Gets the finder map.
Allows applications to modify or add finders programmatically.
The map is threadsafe.

Returns:

the finder map

getServiceFinderClass

protected Class<? extends ServiceFinder> getServiceFinderClass()

Gets the class of the service finder.

Returns:

the class of the service finder, never null

getServiceFinderImpl

protected ServiceFinder getServiceFinderImpl(ClassLoader loader,
                                             String servicePath)

Gets a service finder for a given classloader and service path.
If the finder does not exist yet, it will be created.

Parameters:

loader - the classloader

servicePath - the service path prefix

Returns:

the finder, never null

getServiceFinderImpl

protected ServiceFinder getServiceFinderImpl(String servicePath)

Gets a service finder for a given service path.
If the finder does not exist yet, it will be created. The classloader to use is determined as follows:

1. use the fixed classloader set by setFixedClassLoader(java.lang.ClassLoader), if not null
2. else try Thread.currentThread().getContextClassLoader()
3. if the context classloader is null, use the classloader that loaded the service factory

Parameters:

servicePath - the service path prefix

Returns:

the finder, never null

getServiceFinderImpl

protected ServiceFinder getServiceFinderImpl()

Gets a service finder.
If the finder does not exist yet, it will be created. The classloader used is Thread.currentThread().getContextClassLoader() and the service path is "META_INF/services/".

Returns:

the finder