public abstract class ImageInputStreamSpi extends IIOServiceProvider
ImageInputStreams. 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 ImageInputStreams 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 and Description |
|---|---|
protected Class<?> |
inputClass
A
Class object indicating the legal object type
for use by the createInputStreamInstance method. |
vendorName, version| Modifier | Constructor and 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 and 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, onRegistrationprotected 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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