- All Implemented Interfaces:
RegisterableService
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.
- See Also:
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Field Summary
Modifier and TypeFieldDescriptionprotected Class
<?> AClass
object indicating the legal object type for use by thecreateInputStreamInstance
method.Fields declared in class javax.imageio.spi.IIOServiceProvider
vendorName, version
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Constructor Summary
ModifierConstructorDescriptionprotected
Constructs a blankImageOutputStreamSpi
.ImageOutputStreamSpi
(String vendorName, String version, Class<?> outputClass) Constructs anImageOutputStreamSpi
with a given set of values. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Returnstrue
if theImageOutputStream
implementation associated with this service provider can optionally make use of a cacheFile
for improved performance and/or memory footrprint.createOutputStreamInstance
(Object output) Returns an instance of theImageOutputStream
implementation associated with this service provider.abstract ImageOutputStream
createOutputStreamInstance
(Object output, boolean useCache, File cacheDir) Returns an instance of theImageOutputStream
implementation associated with this service provider.Class
<?> Returns aClass
object representing the class or interface type that must be implemented by an output destination in order to be "wrapped" in anImageOutputStream
via thecreateOutputStreamInstance
method.boolean
Returnstrue
if theImageOutputStream
implementation associated with this service provider requires the use of a cacheFile
.Methods declared in class javax.imageio.spi.IIOServiceProvider
getDescription, getVendorName, getVersion, onDeregistration, onRegistration
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Field Details
-
outputClass
AClass
object indicating the legal object type for use by thecreateInputStreamInstance
method.
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Constructor Details
-
ImageOutputStreamSpi
protected ImageOutputStreamSpi()Constructs a blankImageOutputStreamSpi
. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods. -
ImageOutputStreamSpi
Constructs anImageOutputStreamSpi
with a given set of values.- Parameters:
vendorName
- the vendor name.version
- a version identifier.outputClass
- aClass
object indicating the legal object type for use by thecreateOutputStreamInstance
method.- Throws:
IllegalArgumentException
- ifvendorName
isnull
.IllegalArgumentException
- ifversion
isnull
.
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Method Details
-
getOutputClass
Returns aClass
object representing the class or interface type that must be implemented by an output destination in order to be "wrapped" in anImageOutputStream
via thecreateOutputStreamInstance
method.Typical return values might include
OutputStream.class
orFile.class
, but any class may be used.- Returns:
- a
Class
variable. - See Also:
-
canUseCacheFile
public boolean canUseCacheFile()Returnstrue
if theImageOutputStream
implementation associated with this service provider can optionally make use of a cacheFile
for improved performance and/or memory footrprint. Iffalse
, the value of thecacheFile
argument tocreateOutputStreamInstance
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.
-
needsCacheFile
public boolean needsCacheFile()Returnstrue
if theImageOutputStream
implementation associated with this service provider requires the use of a cacheFile
.The default implementation returns
false
.- Returns:
true
if a cache file is needed by the output streams created by this service provider.
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createOutputStreamInstance
public abstract ImageOutputStream createOutputStreamInstance(Object output, boolean useCache, File cacheDir) throws IOException Returns an instance of theImageOutputStream
implementation associated with this service provider. If the use of a cache file is optional, theuseCache
parameter will be consulted. Where a cache is required, or not applicable, the value ofuseCache
will be ignored.- Parameters:
output
- an object of the class type returned bygetOutputClass
.useCache
- aboolean
indicating whether a cache file should be used, in cases where it is optional.cacheDir
- aFile
indicating where the cache file should be created, ornull
to use the system directory.- Returns:
- an
ImageOutputStream
instance. - Throws:
IllegalArgumentException
- ifoutput
is not an instance of the correct class or isnull
.IllegalArgumentException
- if a cache file is needed, butcacheDir
is non-null
and is not a directory.IOException
- if a cache file is needed but cannot be created.- See Also:
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createOutputStreamInstance
Returns an instance of theImageOutputStream
implementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed.- Parameters:
output
- an object of the class type returned bygetOutputClass
.- Returns:
- an
ImageOutputStream
instance. - Throws:
IllegalArgumentException
- ifoutput
is not an instance of the correct class or isnull
.IOException
- if a cache file is needed but cannot be created.- See Also:
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