Returns true if provider is currently registered.

  Returns true if provider is currently
registered.
Returns: true if the given provider has been registered.
Parameters:
- provider - the service provider object to be queried.
Throws:
- IllegalArgumentException - if provider is null.

Deregisters all currently registered service providers from all categories.

  Deregisters all service provider object currently registered under the given category.

  Deregisters all service provider object currently registered
under the given category.
Parameters:
- category - the category to be emptied.
Throws:
- IllegalArgumentException - if there is no category corresponding to category.

  Removes a service provider object from all categories that contain it.

  Removes a service provider object from all categories that
contain it.
Parameters:
- provider - the service provider object to be deregistered.
Throws:
- IllegalArgumentException - if provider is null.

  Removes a service provider object from the given category.

  Removes a service provider object from the given category. If the provider was not previously registered, nothing happens and false is returned. Otherwise, true is returned. If an object of the same class as provider but not equal (using ==) to provider is registered, it will not be deregistered.

If provider implements the RegisterableService interface, its onDeregistration method will be called.
Returns: true if the provider was previously registered in the same category category, false otherwise.
Parameters:
- provider - the service provider object to be deregistered.
- category - the category from which to deregister the provider.
Throws:
- IllegalArgumentException - if provider is null.
- IllegalArgumentException - if there is no category corresponding to category.
- ClassCastException - if provider does not implement the class defined by category.

  Finalizes this object prior to garbage collection.

  Finalizes this object prior to garbage collection. The
deregisterAll method is called to deregister all
currently registered service providers. This method should not
be called from application code.
Throws:
- Throwable - if an error occurs during superclass finalization.

  Returns an Iterator of Class objects indicating the current set of categories.

  Returns an Iterator of Class objects
indicating the current set of categories. The iterator will be
empty if no categories exist.
Returns: an Iterator containing Classobjects.

  Returns the currently registered service provider object that is of the given class type.

  Returns the currently registered service provider object that
is of the given class type. At most one object of a given
class is allowed to be registered at any given time. If no
registered object has the desired class type, null
is returned.
Returns: a currently registered service provider object with the desired Classtype, or null is none is present.
Parameters:
- providerClass - the Class of the desired service provider object.
Throws:
- IllegalArgumentException - if providerClass is null.

  Returns an Iterator containing all registered service providers in the given category.

  Returns an Iterator containing all registered
service providers in the given category. If
useOrdering is false, the iterator
will return all of the server provider objects in an arbitrary
order. Otherwise, the ordering will respect any pairwise
orderings that have been set. If the graph of pairwise
orderings contains cycles, any providers that belong to a cycle
will not be returned.
Returns: an Iterator containing service provider objects from the given category, possibly in order.
Parameters:
- category - the category to be retrieved from.
- useOrdering - true if pairwise orderings should be taken account in ordering the returned objects.
Throws:
- IllegalArgumentException - if there is no category corresponding to category.

  Returns an Iterator containing service provider objects within a given category that satisfy a criterion imposed by the supplied ServiceRegistry.Filter object's filter method.

  Returns an Iterator containing service provider objects within a given category that satisfy a criterion imposed by the supplied ServiceRegistry.Filter object's filter method.

The useOrdering argument controls the ordering of the results using the same rules as getServiceProviders(Class, boolean).
Returns: an Iterator containing service provider objects from the given category, possibly in order.
Parameters:
- category - the category to be retrieved from.
- filter - an instance of ServiceRegistry.Filter whose filter method will be invoked.
- useOrdering - true if pairwise orderings should be taken account in ordering the returned objects.
Throws:
- IllegalArgumentException - if there is no category corresponding to category.

  Locates and incrementally instantiates the available providers of a given service using the context class loader.

  Locates and incrementally instantiates the available providers
of a given service using the context class loader. This
convenience method is equivalent to:

   ClassLoader cl = Thread.currentThread().getContextClassLoader();
   return Service.providers(service, cl);
 

Returns: An Iterator that yields provider objects for the given service, in some arbitrary order. The iterator will throw an Error if a provider-configuration file violates the specified format or if a provider class cannot be found and instantiated.
Parameters:
- providerClass - a Classobject indicating the class or interface of the service providers being detected.
Throws:
- IllegalArgumentException - if providerClass is null.

  Searches for implementations of a particular service class using the given class loader.

  Searches for implementations of a particular service class using the given class loader.

This method transforms the name of the given service class into a provider-configuration filename as described in the class comment and then uses the getResources method of the given class loader to find all available files with that name. These files are then read and parsed to produce a list of provider-class names. The iterator that is returned uses the given class loader to look up and then instantiate each element of the list.

Because it is possible for extensions to be installed into a running Java virtual machine, this method may return different results each time it is invoked.
Returns: An Iterator that yields provider objects for the given service, in some arbitrary order. The iterator will throw an Error if a provider-configuration file violates the specified format or if a provider class cannot be found and instantiated.
Parameters:
- providerClass - a Classobject indicating the class or interface of the service providers being detected.
- loader - the class loader to be used to load provider-configuration files and instantiate provider classes, or null if the system class loader (or, failing that the bootstrap class loader) is to be used.
Throws:
- IllegalArgumentException - if providerClass is null.

  Adds a service provider object to the registry.

  Adds a service provider object to the registry. The provider is associated within each category present in the registry whose Class it implements.

If provider implements the RegisterableService interface, its onRegistration method will be called once for each category it is registered under. Its onDeregistration method will be called each time it is deregistered from a category or when the registry is finalized.
Parameters:
- provider - the service provider object to be registered.
Throws:
- IllegalArgumentException - if provider is null.

  Adds a service provider object to the registry.

  Adds a service provider object to the registry. The provider is associated with the given category.

If provider implements the RegisterableService interface, its onRegistration method will be called. Its onDeregistration method will be called each time it is deregistered from a category, for example if a category is removed or the registry is garbage collected.
Returns: true if no provider of the same class was previously registered in the same category category.
Parameters:
- provider - the service provide object to be registered.
- category - the category under which to register the provider.
Throws:
- IllegalArgumentException - if provider is null.
- IllegalArgumentException - if there is no category corresponding to category.
- ClassCastException - if provider does not implement the Class defined by category.

  Adds a set of service provider objects, taken from an Iterator to the registry.

  Adds a set of service provider objects, taken from an Iterator to the registry. Each provider is associated within each category present in the registry whose Class it implements.

For each entry of providers that implements the RegisterableService interface, its onRegistration method will be called once for each category it is registered under. Its onDeregistration method will be called each time it is deregistered from a category or when the registry is finalized.
Parameters:
- providers - an Iterator containing service provider objects to be registered.
Throws:
- IllegalArgumentException - if providers is null or contains a null entry.

  Sets a pairwise ordering between two service provider objects within a given category.

  Sets a pairwise ordering between two service provider objects within a given category. If one or both objects are not currently registered within the given category, or if the desired ordering is already set, nothing happens and false is returned. If the providers previously were ordered in the reverse direction, that ordering is removed.

The ordering will be used by the getServiceProviders methods when their useOrdering argument is true.
Returns: true if a previously unset ordering was established.
Parameters:
- category - a Class object indicating the category under which the preference is to be established.
- firstProvider - the preferred provider.
- secondProvider - the provider to which firstProvider is preferred.
Throws:
- IllegalArgumentException - if either provider is null or they are the same object.
- IllegalArgumentException - if there is no category corresponding to category.

  Sets a pairwise ordering between two service provider objects within a given category.

  Sets a pairwise ordering between two service provider objects within a given category. If one or both objects are not currently registered within the given category, or if no ordering is currently set between them, nothing happens and false is returned.

The ordering will be used by the getServiceProviders methods when their useOrdering argument is true.
Returns: true if a previously set ordering was disestablished.
Parameters:
- category - a Class object indicating the category under which the preference is to be disestablished.
- firstProvider - the formerly preferred provider.
- secondProvider - the provider to which firstProvider was formerly preferred.
Throws:
- IllegalArgumentException - if either provider is null or they are the same object.
- IllegalArgumentException - if there is no category corresponding to category.