RegisterableService
public abstract class ImageInputStreamSpi extends IIOServiceProvider
ImageInputStream
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 ImageInputStream
. For example,
a particular ImageInputStreamSpi
might allow
a generic InputStream
to be used as an input source;
another might take input from a URL
.
By treating the creation of ImageInputStream
s as a
pluggable service, it becomes possible to handle future input
sources without changing the API. Also, high-performance
implementations of ImageInputStream
(for example,
native implementations for a particular platform) can be installed
and used transparently by applications.
IIORegistry
,
ImageInputStream
Modifier and Type | Field | Description |
---|---|---|
protected Class<?> |
inputClass |
A
Class object indicating the legal object type
for use by the createInputStreamInstance method. |
vendorName, version
Modifier | Constructor | Description |
---|---|---|
protected |
ImageInputStreamSpi() |
Constructs a blank
ImageInputStreamSpi . |
|
ImageInputStreamSpi(String vendorName,
String version,
Class<?> inputClass) |
Constructs an
ImageInputStreamSpi with a given set
of values. |
Modifier and Type | Method | Description |
---|---|---|
boolean |
canUseCacheFile() |
Returns
true if the ImageInputStream
implementation associated with this service provider can
optionally make use of a cache file for improved performance
and/or memory footrprint. |
ImageInputStream |
createInputStreamInstance(Object input) |
Returns an instance of the
ImageInputStream
implementation associated with this service provider. |
abstract ImageInputStream |
createInputStreamInstance(Object input,
boolean useCache,
File cacheDir) |
Returns an instance of the
ImageInputStream
implementation associated with this service provider. |
Class<?> |
getInputClass() |
Returns a
Class object representing the class or
interface type that must be implemented by an input source in
order to be "wrapped" in an ImageInputStream via
the createInputStreamInstance method. |
boolean |
needsCacheFile() |
Returns
true if the ImageInputStream
implementation associated with this service provider requires
the use of a cache File . |
getDescription, getVendorName, getVersion, onDeregistration, onRegistration
protected Class<?> inputClass
Class
object indicating the legal object type
for use by the createInputStreamInstance
method.protected ImageInputStreamSpi()
ImageInputStreamSpi
. 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 ImageInputStreamSpi(String vendorName, String version, Class<?> inputClass)
ImageInputStreamSpi
with a given set
of values.vendorName
- the vendor name.version
- a version identifier.inputClass
- a Class
object indicating the
legal object type for use by the
createInputStreamInstance
method.IllegalArgumentException
- if vendorName
is null
.IllegalArgumentException
- if version
is null
.public Class<?> getInputClass()
Class
object representing the class or
interface type that must be implemented by an input source in
order to be "wrapped" in an ImageInputStream
via
the createInputStreamInstance
method.
Typical return values might include
InputStream.class
or URL.class
, but
any class may be used.
Class
variable.createInputStreamInstance(Object, boolean, File)
public boolean canUseCacheFile()
true
if the ImageInputStream
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 useCache
argument to
createInputStreamInstance
will be ignored.
The default implementation returns false
.
true
if a cache file can be used by the
input streams created by this service provider.public boolean needsCacheFile()
true
if the ImageInputStream
implementation associated with this service provider requires
the use of a cache File
. If true
,
the value of the useCache
argument to
createInputStreamInstance
will be ignored.
The default implementation returns false
.
true
if a cache file is needed by the
input streams created by this service provider.public abstract ImageInputStream createInputStreamInstance(Object input, boolean useCache, File cacheDir) throws IOException
ImageInputStream
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.input
- an object of the class type returned by
getInputClass
.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.ImageInputStream
instance.IllegalArgumentException
- if input
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.getInputClass()
,
canUseCacheFile()
,
needsCacheFile()
public ImageInputStream createInputStreamInstance(Object input) throws IOException
ImageInputStream
implementation associated with this service provider. A cache
file will be created in the system-dependent default
temporary-file directory, if needed.input
- an object of the class type returned by
getInputClass
.ImageInputStream
instance.IllegalArgumentException
- if input
is
not an instance of the correct class or is null
.IOException
- if a cache file is needed but cannot be
created.getInputClass()
Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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DRAFT 9-internal+0-adhoc.mlchung.jdk9-jdeps