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package javax.imageio.spi;

import java.io.File;
import java.io.IOException;
import javax.imageio.stream.ImageOutputStream;

The service provider interface (SPI) for ImageOutputStreams. For more information on service provider interfaces, see the class comment for the IIORegistry class. 
 This interface allows arbitrary objects to be "wrapped" by instances of ImageOutputStream. For example, a particular ImageOutputStreamSpi might allow a generic OutputStream to be used as a destination; another might output to a File or to a device such as a serial port. 
 By treating the creation of ImageOutputStreams as a pluggable service, it becomes possible to handle future output destinations without changing the API. Also, high-performance implementations of ImageOutputStream (for example, native implementations for a particular platform) can be installed and used transparently by applications. 
See Also:
IIORegistry
ImageOutputStream/**
 * The service provider interface (SPI) for
 * {@code ImageOutputStream}s.  For more information on service
 * provider interfaces, see the class comment for the
 * {@code IIORegistry} class.
 *
 * <p> This interface allows arbitrary objects to be "wrapped" by
 * instances of {@code ImageOutputStream}.  For example, a
 * particular {@code ImageOutputStreamSpi} might allow a generic
 * {@code OutputStream} to be used as a destination; another
 * might output to a {@code File} or to a device such as a serial
 * port.
 *
 * <p> By treating the creation of {@code ImageOutputStream}s as
 * a pluggable service, it becomes possible to handle future output
 * destinations without changing the API.  Also, high-performance
 * implementations of {@code ImageOutputStream} (for example,
 * native implementations for a particular platform) can be installed
 * and used transparently by applications.
 *
 * @see IIORegistry
 * @see javax.imageio.stream.ImageOutputStream
 *
 */
public abstract class ImageOutputStreamSpi extends IIOServiceProvider {

    
A Class object indicating the legal object type for use by the createInputStreamInstance method. /**
     * A {@code Class} object indicating the legal object type
     * for use by the {@code createInputStreamInstance} method.
     */
    protected Class<?> outputClass;

    
Constructs a blank ImageOutputStreamSpi. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods. /**
     * Constructs a blank {@code ImageOutputStreamSpi}.  It is up
     * to the subclass to initialize instance variables and/or
     * override method implementations in order to provide working
     * versions of all methods.
     */
    protected ImageOutputStreamSpi() {
    }

    
Constructs an ImageOutputStreamSpi with a given set of values. 
Params:
vendorName – the vendor name.
version – a version identifier.
outputClass – a Class object indicating the legal object type for use by the createOutputStreamInstance method.
Throws:
IllegalArgumentException – if vendorName is null.
IllegalArgumentException – if version is null./**
     * Constructs an {@code ImageOutputStreamSpi} with a given
     * set of values.
     *
     * @param vendorName the vendor name.
     * @param version a version identifier.
     * @param outputClass a {@code Class} object indicating the
     * legal object type for use by the
     * {@code createOutputStreamInstance} method.
     *
     * @exception IllegalArgumentException if {@code vendorName}
     * is {@code null}.
     * @exception IllegalArgumentException if {@code version}
     * is {@code null}.
    */
    public ImageOutputStreamSpi(String vendorName,
                                String version,
                                Class<?> outputClass) {
        super(vendorName, version);
        this.outputClass = outputClass;
    }

    
Returns a Class object representing the class or interface type that must be implemented by an output destination in order to be "wrapped" in an ImageOutputStream via the createOutputStreamInstance method. 
 Typical return values might include OutputStream.class or File.class, but any class may be used. 
See Also:
createOutputStreamInstance(Object, boolean, File)
Returns:
a Class variable./**
     * Returns a {@code Class} object representing the class or
     * interface type that must be implemented by an output
     * destination in order to be "wrapped" in an
     * {@code ImageOutputStream} via the
     * {@code createOutputStreamInstance} method.
     *
     * <p> Typical return values might include
     * {@code OutputStream.class} or {@code File.class}, but
     * any class may be used.
     *
     * @return a {@code Class} variable.
     *
     * @see #createOutputStreamInstance(Object, boolean, File)
     */
    public Class<?> getOutputClass() {
        return outputClass;
    }

    
Returns true if the ImageOutputStream implementation associated with this service provider can optionally make use of a cache File for improved performance and/or memory footrprint. If false, the value of the cacheFile argument to createOutputStreamInstance will be ignored. 
 The default implementation returns false. 
Returns:
true if a cache file can be used by the output streams created by this service provider./**
     * Returns {@code true} if the {@code ImageOutputStream}
     * implementation associated with this service provider can
     * optionally make use of a cache {@code File} for improved
     * performance and/or memory footrprint.  If {@code false},
     * the value of the {@code cacheFile} argument to
     * {@code createOutputStreamInstance} will be ignored.
     *
     * <p> The default implementation returns {@code false}.
     *
     * @return {@code true} if a cache file can be used by the
     * output streams created by this service provider.
     */
    public boolean canUseCacheFile() {
        return false;
    }

    
Returns true if the ImageOutputStream implementation associated with this service provider requires the use of a cache File. 
 The default implementation returns false. 
Returns:
true if a cache file is needed by the output streams created by this service provider./**
     * Returns {@code true} if the {@code ImageOutputStream}
     * implementation associated with this service provider requires
     * the use of a cache {@code File}.
     *
     * <p> The default implementation returns {@code false}.
     *
     * @return {@code true} if a cache file is needed by the
     * output streams created by this service provider.
     */
    public boolean needsCacheFile() {
        return false;
    }

    
Returns an instance of the ImageOutputStream implementation associated with this service provider. If the use of a cache file is optional, the useCache parameter will be consulted. Where a cache is required, or not applicable, the value of useCache will be ignored. 
Params:
output – an object of the class type returned by getOutputClass.
useCache – a boolean indicating whether a cache file should be used, in cases where it is optional.
cacheDir – a File indicating where the cache file should be created, or null to use the system directory.
Throws:
IllegalArgumentException – if output is not an instance of the correct class or is null.
IllegalArgumentException – if a cache file is needed, but cacheDir is non-null and is not a directory.
IOException – if a cache file is needed but cannot be
created.
See Also:
getOutputClass
Returns:
an ImageOutputStream instance./**
     * Returns an instance of the {@code ImageOutputStream}
     * implementation associated with this service provider.  If the
     * use of a cache file is optional, the {@code useCache}
     * parameter will be consulted.  Where a cache is required, or
     * not applicable, the value of {@code useCache} will be ignored.
     *
     * @param output an object of the class type returned by
     * {@code getOutputClass}.
     * @param useCache a {@code boolean} indicating whether a
     * cache file should be used, in cases where it is optional.
     * @param cacheDir a {@code File} indicating where the
     * cache file should be created, or {@code null} to use the
     * system directory.
     *
     * @return an {@code ImageOutputStream} instance.
     *
     * @exception IllegalArgumentException if {@code output} is
     * not an instance of the correct class or is {@code null}.
     * @exception IllegalArgumentException if a cache file is needed,
     * but {@code cacheDir} is non-{@code null} and is not a
     * directory.
     * @exception IOException if a cache file is needed but cannot be
     * created.
     *
     * @see #getOutputClass
     */
    public abstract
        ImageOutputStream createOutputStreamInstance(Object output,
                                                     boolean useCache,
                                                     File cacheDir)
        throws IOException;

    
Returns an instance of the ImageOutputStream implementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed. 
Params:
output – an object of the class type returned by getOutputClass.
Throws:
IllegalArgumentException – if output is not an instance of the correct class or is null.
IOException – if a cache file is needed but cannot be
created.
See Also:
getOutputClass()
Returns:
an ImageOutputStream instance./**
     * Returns an instance of the {@code ImageOutputStream}
     * implementation associated with this service provider.  A cache
     * file will be created in the system-dependent default
     * temporary-file directory, if needed.
     *
     * @param output an object of the class type returned by
     * {@code getOutputClass}.
     *
     * @return an {@code ImageOutputStream} instance.
     *
     * @exception IllegalArgumentException if {@code output} is
     * not an instance of the correct class or is {@code null}.
     * @exception IOException if a cache file is needed but cannot be
     * created.
     *
     * @see #getOutputClass()
     */
    public ImageOutputStream createOutputStreamInstance(Object output)
        throws IOException {
        return createOutputStreamInstance(output, true, null);
    }
}