Class IIORegistry

java.lang.Object

javax.imageio.spi.ServiceRegistry

javax.imageio.spi.IIORegistry

public final class IIORegistry
extends ServiceRegistry

A registry for Image I/O service provider instances. Service provider classes may be discovered at runtime by the mechanisms documented in ServiceLoader. The intent is that it be relatively inexpensive to load and inspect all available Image I/O service provider classes. These classes may then be used to locate and instantiate more heavyweight classes that will perform actual work, in this case instances of ImageReader, ImageWriter, ImageTranscoder, ImageInputStream, and ImageOutputStream. Service providers included in the Java runtime are automatically loaded as soon as this class is instantiated.

When the registerApplicationClasspathSpis method is called, additional service provider instances will be discovered using ServiceLoader.

It is also possible to manually add service providers not found automatically, as well as to remove those that are using the interfaces of the ServiceRegistry class. Thus the application may customize the contents of the registry as it sees fit.

For information on how to create and deploy service providers, refer to the documentation on ServiceLoader

Nested Class Summary

Nested classes/interfaces declared in class ServiceRegistry

ServiceRegistry.Filter

Modifier and Type	Class	Description
static interface	ServiceRegistry.Filter	A simple filter interface used by ServiceRegistry.getServiceProviders to select providers matching an arbitrary criterion.

Method Summary

Modifier and Type	Method	Description
static IIORegistry	getDefaultInstance()	Returns the default IIORegistry instance used by the Image I/O API.
void	registerApplicationClasspathSpis()	Registers all available service providers found on the application class path, using the default ClassLoader.

Methods declared in class ServiceRegistry

contains, deregisterAll, deregisterAll, deregisterServiceProvider, deregisterServiceProvider, getCategories, getServiceProviderByClass, getServiceProviders, getServiceProviders, lookupProviders, lookupProviders, registerServiceProvider, registerServiceProvider, registerServiceProviders, setOrdering, unsetOrdering

Modifier and Type	Method	Description
boolean	contains(Object provider)	Returns true if provider is currently registered.
void	deregisterAll()	Deregisters all currently registered service providers from all categories.
void	deregisterAll(Class<?> category)	Deregisters all service provider object currently registered under the given category.
void	deregisterServiceProvider(Object provider)	Removes a service provider object from all categories that contain it.
<T> boolean	deregisterServiceProvider(T provider, Class<T> category)	Removes a service provider object from the given category.
Iterator<Class<?>>	getCategories()	Returns an Iterator of Class objects indicating the current set of categories.
<T> T	getServiceProviderByClass(Class<T> providerClass)	Returns the currently registered service provider object that is of the given class type.
<T> Iterator<T>	getServiceProviders(Class<T> category, boolean useOrdering)	Returns an Iterator containing all registered service providers in the given category.
<T> Iterator<T>	getServiceProviders(Class<T> category, ServiceRegistry.Filter filter, boolean useOrdering)	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.
static <T> Iterator<T>	lookupProviders(Class<T> providerClass)	Locates and incrementally instantiates the available providers of a given service using the context class loader.
static <T> Iterator<T>	lookupProviders(Class<T> providerClass, ClassLoader loader)	Searches for implementations of a particular service class using the given class loader.
void	registerServiceProvider(Object provider)	Adds a service provider object to the registry.
<T> boolean	registerServiceProvider(T provider, Class<T> category)	Adds a service provider object to the registry.
void	registerServiceProviders(Iterator<?> providers)	Adds a set of service provider objects, taken from an Iterator to the registry.
<T> boolean	setOrdering(Class<T> category, T firstProvider, T secondProvider)	Sets a pairwise ordering between two service provider objects within a given category.
<T> boolean	unsetOrdering(Class<T> category, T firstProvider, T secondProvider)	Sets a pairwise ordering between two service provider objects within a given category.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Method Details

getDefaultInstance

public static IIORegistry getDefaultInstance()

Returns the default IIORegistry instance used by the Image I/O API. This instance should be used for all registry functions.

Returns:

the default registry for the Image I/O API

registerApplicationClasspathSpis

public void registerApplicationClasspathSpis()

Registers all available service providers found on the application class path, using the default ClassLoader. This method is typically invoked by the ImageIO.scanForPlugins method.

See Also:

• ImageIO.scanForPlugins()
• ClassLoader.getResources(String)