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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</code>s.  For more information on service
 * provider interfaces, see the class comment for the
 * <code>IIORegistry</code> class.
 *
 * <p> This interface allows arbitrary objects to be "wrapped" by
 * instances of <code>ImageOutputStream</code>.  For example, a
 * particular <code>ImageOutputStreamSpi</code> might allow a generic
 * <code>OutputStream</code> to be used as a destination; another
 * might output to a <code>File</code> or to a device such as a serial
 * port.
 *
 * <p> By treating the creation of <code>ImageOutputStream</code>s as
 * a pluggable service, it becomes possible to handle future output
 * destinations without changing the API.  Also, high-performance
 * implementations of <code>ImageOutputStream</code> (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</code> object indicating the legal object type
     * for use by the <code>createInputStreamInstance</code> 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</code>.  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</code> with a given
     * set of values.
     *
     * @param vendorName the vendor name.
     * @param version a version identifier.
     * @param outputClass a <code>Class</code> object indicating the
     * legal object type for use by the
     * <code>createOutputStreamInstance</code> method.
     *
     * @exception IllegalArgumentException if <code>vendorName</code>
     * is <code>null</code>.
     * @exception IllegalArgumentException if <code>version</code>
     * is <code>null</code>.
    */
    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</code> object representing the class or
     * interface type that must be implemented by an output
     * destination in order to be "wrapped" in an
     * <code>ImageOutputStream</code> via the
     * <code>createOutputStreamInstance</code> method.
     *
     * <p> Typical return values might include
     * <code>OutputStream.class</code> or <code>File.class</code>, but
     * any class may be used.
     *
     * @return a <code>Class</code> 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</code> if the <code>ImageOutputStream</code>
     * implementation associated with this service provider can
     * optionally make use of a cache <code>File</code> for improved
     * performance and/or memory footrprint.  If <code>false</code>,
     * the value of the <code>cacheFile</code> argument to
     * <code>createOutputStreamInstance</code> will be ignored.
     *
     * <p> The default implementation returns <code>false</code>.
     *
     * @return <code>true</code> 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</code> if the <code>ImageOutputStream</code>
     * implementation associated with this service provider requires
     * the use of a cache <code>File</code>.
     *
     * <p> The default implementation returns <code>false</code>.
     *
     * @return <code>true</code> 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</code>
     * implementation associated with this service provider.  If the
     * use of a cache file is optional, the <code>useCache</code>
     * parameter will be consulted.  Where a cache is required, or
     * not applicable, the value of <code>useCache</code> will be ignored.
     *
     * @param output an object of the class type returned by
     * <code>getOutputClass</code>.
     * @param useCache a <code>boolean</code> indicating whether a
     * cache file should be used, in cases where it is optional.
     * @param cacheDir a <code>File</code> indicating where the
     * cache file should be created, or <code>null</code> to use the
     * system directory.
     *
     * @return an <code>ImageOutputStream</code> instance.
     *
     * @exception IllegalArgumentException if <code>output</code> is
     * not an instance of the correct class or is <code>null</code>.
     * @exception IllegalArgumentException if a cache file is needed,
     * but <code>cacheDir</code> is non-<code>null</code> 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</code>
     * 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</code>.
     *
     * @return an <code>ImageOutputStream</code> instance.
     *
     * @exception IllegalArgumentException if <code>output</code> is
     * not an instance of the correct class or is <code>null</code>.
     * @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);
    }
}