RegisterableService
public abstract class ImageOutputStreamSpi extends IIOServiceProvider
ImageOutputStream
s. 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 ImageOutputStream
s 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.
Modifier and Type | Field | Description |
---|---|---|
protected Class |
outputClass |
A Class object indicating the legal object type for use by the createInputStreamInstance method. |
vendorName, version
Modifier | Constructor | Description |
---|---|---|
protected |
Constructs a blank ImageOutputStreamSpi . |
|
Constructs an ImageOutputStreamSpi with a given set of values. |
Modifier and Type | Method | Description |
---|---|---|
boolean |
canUseCacheFile() |
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. |
ImageOutputStream |
createOutputStreamInstance |
Returns an instance of the ImageOutputStream implementation associated with this service provider. |
abstract ImageOutputStream |
createOutputStreamInstance |
Returns an instance of the ImageOutputStream implementation associated with this service provider. |
Class |
getOutputClass() |
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. |
boolean |
needsCacheFile() |
Returns true if the ImageOutputStream implementation associated with this service provider requires the use of a cache File . |
getDescription, getVendorName, getVersion, onDeregistration, onRegistration
protected Class<?> outputClass
Class
object indicating the legal object type for use by the createInputStreamInstance
method.protected ImageOutputStreamSpi()
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.public ImageOutputStreamSpi(String vendorName, String version, Class<?> outputClass)
ImageOutputStreamSpi
with a given set of values.vendorName
- the vendor name.version
- a version identifier.outputClass
- a Class
object indicating the legal object type for use by the createOutputStreamInstance
method.IllegalArgumentException
- if vendorName
is null
.IllegalArgumentException
- if version
is null
.public Class<?> getOutputClass()
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.
Class
variable.public boolean canUseCacheFile()
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
.
true
if a cache file can be used by the output streams created by this service provider.public boolean needsCacheFile()
true
if the ImageOutputStream
implementation associated with this service provider requires the use of a cache File
. The default implementation returns false
.
true
if a cache file is needed by the output streams created by this service provider.public abstract ImageOutputStream createOutputStreamInstance(Object output, boolean useCache, File cacheDir) throws IOException
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.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.ImageOutputStream
instance.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.public ImageOutputStream createOutputStreamInstance(Object output) throws IOException
ImageOutputStream
implementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed.output
- an object of the class type returned by getOutputClass
.ImageOutputStream
instance.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.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/imageio/spi/ImageOutputStreamSpi.html