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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
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package javax.imageio.spi;
import java.security.PrivilegedAction;
import java.security.AccessController;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.Vector;
import com.sun.imageio.spi.FileImageInputStreamSpi;
import com.sun.imageio.spi.FileImageOutputStreamSpi;
import com.sun.imageio.spi.InputStreamImageInputStreamSpi;
import com.sun.imageio.spi.OutputStreamImageOutputStreamSpi;
import com.sun.imageio.spi.RAFImageInputStreamSpi;
import com.sun.imageio.spi.RAFImageOutputStreamSpi;
import com.sun.imageio.plugins.gif.GIFImageReaderSpi;
import com.sun.imageio.plugins.gif.GIFImageWriterSpi;
import com.sun.imageio.plugins.jpeg.JPEGImageReaderSpi;
import com.sun.imageio.plugins.jpeg.JPEGImageWriterSpi;
import com.sun.imageio.plugins.png.PNGImageReaderSpi;
import com.sun.imageio.plugins.png.PNGImageWriterSpi;
import com.sun.imageio.plugins.bmp.BMPImageReaderSpi;
import com.sun.imageio.plugins.bmp.BMPImageWriterSpi;
import com.sun.imageio.plugins.wbmp.WBMPImageReaderSpi;
import com.sun.imageio.plugins.wbmp.WBMPImageWriterSpi;
import com.sun.imageio.plugins.tiff.TIFFImageReaderSpi;
import com.sun.imageio.plugins.tiff.TIFFImageWriterSpi;
import sun.awt.AppContext;
import java.util.ServiceLoader;
import java.util.ServiceConfigurationError;
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
/**
* A registry for Image I/O service provider instances. Service provider
* classes may be discovered at runtime by the mechanisms documented in
* {@link java.util.ServiceLoader 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 {@code ImageReader},
* {@code ImageWriter}, {@code ImageTranscoder},
* {@code ImageInputStream}, and {@code ImageOutputStream}.
*
* Service providers included in the Java runtime are automatically
* loaded as soon as this class is instantiated.
*
* <p> When the {@code registerApplicationClasspathSpis} method
* is called, additional service provider instances will be discovered
* using {@link java.util.ServiceLoader ServiceLoader}.
*
* <p> 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 {@code ServiceRegistry} class. Thus
* the application may customize the contents of the registry as it
* sees fit.
*
* <p> For information on how to create and deploy service providers,
* refer to the documentation on {@link java.util.ServiceLoader ServiceLoader}
*/
public final class IIORegistry extends ServiceRegistry {
A Vector containing the valid IIO registry categories (superinterfaces) to be used in the constructor. /**
* A {@code Vector} containing the valid IIO registry
* categories (superinterfaces) to be used in the constructor.
*/
private static final Vector<Class<?>> initialCategories = new Vector<>(5);
static {
initialCategories.add(ImageReaderSpi.class);
initialCategories.add(ImageWriterSpi.class);
initialCategories.add(ImageTranscoderSpi.class);
initialCategories.add(ImageInputStreamSpi.class);
initialCategories.add(ImageOutputStreamSpi.class);
}
Set up the valid service provider categories and automatically
register all available service providers.
The constructor is private in order to prevent creation of
additional instances.
/**
* Set up the valid service provider categories and automatically
* register all available service providers.
*
* <p> The constructor is private in order to prevent creation of
* additional instances.
*/
private IIORegistry() {
super(initialCategories.iterator());
registerStandardSpis();
registerApplicationClasspathSpis();
}
Returns the default IIORegistry instance used by the Image I/O API. This instance should be used for all registry functions. Each ThreadGroup will receive its own instance; this allows different Applets in the same browser (for example) to each have their own registry.
Returns: the default registry for the current ThreadGroup.
/**
* Returns the default {@code IIORegistry} instance used by
* the Image I/O API. This instance should be used for all
* registry functions.
*
* <p> Each {@code ThreadGroup} will receive its own
* instance; this allows different {@code Applet}s in the
* same browser (for example) to each have their own registry.
*
* @return the default registry for the current
* {@code ThreadGroup}.
*/
public static IIORegistry getDefaultInstance() {
AppContext context = AppContext.getAppContext();
IIORegistry registry =
(IIORegistry)context.get(IIORegistry.class);
if (registry == null) {
// Create an instance for this AppContext
registry = new IIORegistry();
context.put(IIORegistry.class, registry);
}
return registry;
}
private void registerStandardSpis() {
// Hardwire standard SPIs
registerServiceProvider(new GIFImageReaderSpi());
registerServiceProvider(new GIFImageWriterSpi());
registerServiceProvider(new BMPImageReaderSpi());
registerServiceProvider(new BMPImageWriterSpi());
registerServiceProvider(new WBMPImageReaderSpi());
registerServiceProvider(new WBMPImageWriterSpi());
registerServiceProvider(new TIFFImageReaderSpi());
registerServiceProvider(new TIFFImageWriterSpi());
registerServiceProvider(new PNGImageReaderSpi());
registerServiceProvider(new PNGImageWriterSpi());
registerServiceProvider(new JPEGImageReaderSpi());
registerServiceProvider(new JPEGImageWriterSpi());
registerServiceProvider(new FileImageInputStreamSpi());
registerServiceProvider(new FileImageOutputStreamSpi());
registerServiceProvider(new InputStreamImageInputStreamSpi());
registerServiceProvider(new OutputStreamImageOutputStreamSpi());
registerServiceProvider(new RAFImageInputStreamSpi());
registerServiceProvider(new RAFImageOutputStreamSpi());
registerInstalledProviders();
}
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:
/**
* Registers all available service providers found on the
* application class path, using the default
* {@code ClassLoader}. This method is typically invoked by
* the {@code ImageIO.scanForPlugins} method.
*
* @see javax.imageio.ImageIO#scanForPlugins
* @see ClassLoader#getResources
*/
public void registerApplicationClasspathSpis() {
// FIX: load only from application classpath
ClassLoader loader = Thread.currentThread().getContextClassLoader();
Iterator<Class<?>> categories = getCategories();
while (categories.hasNext()) {
@SuppressWarnings("unchecked")
Class<IIOServiceProvider> c = (Class<IIOServiceProvider>)categories.next();
Iterator<IIOServiceProvider> riter =
ServiceLoader.load(c, loader).iterator();
while (riter.hasNext()) {
try {
// Note that the next() call is required to be inside
// the try/catch block; see 6342404.
IIOServiceProvider r = riter.next();
registerServiceProvider(r);
} catch (ServiceConfigurationError err) {
if (System.getSecurityManager() != null) {
// In the applet case, we will catch the error so
// registration of other plugins can proceed
err.printStackTrace();
} else {
// In the application case, we will throw the
// error to indicate app/system misconfiguration
throw err;
}
}
}
}
}
private void registerInstalledProviders() {
/*
We need to load installed providers
in the privileged mode in order to
be able read corresponding jar files even if
file read capability is restricted (like the
applet context case).
*/
PrivilegedAction<Object> doRegistration =
new PrivilegedAction<Object>() {
public Object run() {
Iterator<Class<?>> categories = getCategories();
while (categories.hasNext()) {
@SuppressWarnings("unchecked")
Class<IIOServiceProvider> c = (Class<IIOServiceProvider>)categories.next();
for (IIOServiceProvider p : ServiceLoader.loadInstalled(c)) {
registerServiceProvider(p);
}
}
return this;
}
};
AccessController.doPrivileged(doRegistration);
}
}
