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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* 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).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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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
* {@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 {@code Class} object indicating the legal object type
* for use by the {@code createInputStreamInstance} method.
*/
protected Class<?> outputClass;
/**
* 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 {@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 {@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 {@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 {@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 {@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 {@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);
}
}