APIdia Launch Partner
Top Description Fields Constructors Methods
javax.imageio.spi

public abstract Class ImageInputStreamSpi

extends IIOServiceProvider
Class Inheritance
Known Direct Subclasses
com.sun.imageio.spi.FileImageInputStreamSpi, com.sun.imageio.spi.InputStreamImageInputStreamSpi, com.sun.imageio.spi.RAFImageInputStreamSpi
Imports
java.io.File, .IOException, javax.imageio.stream.ImageInputStream
The service provider interface (SPI) for 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.

See Also
IIORegistry, javax.imageio.stream.ImageInputStream

Field Summary

Modifier and TypeField and Description
protected Class<?>
inputClass

A Class object indicating the legal object type for use by the createInputStreamInstance method.

Inherited from javax.imageio.spi.IIOServiceProvider:
vendorNameversion

Constructor Summary

AccessConstructor and Description
protected
ImageInputStreamSpi()

Constructs a blank ImageInputStreamSpi.

public
ImageInputStreamSpi(String
the vendor name.
vendorName, String
a version identifier.
version, Class<?>
a Class object indicating the legal object type for use by the createInputStreamInstance method.
inputClass)

Constructs an ImageInputStreamSpi with a given set of values.

Method Summary

Modifier and TypeMethod and Description
public boolean

Returns:

true if a cache file can be used by the input streams created by this service provider.
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.

public abstract ImageInputStream

Returns:

an ImageInputStream instance.
createInputStreamInstance(Object
an object of the class type returned by getInputClass.
input, boolean
a boolean indicating whether a cache file should be used, in cases where it is optional.
useCache, File
a File indicating where the cache file should be created, or null to use the system directory.
cacheDir)

Returns an instance of the ImageInputStream implementation associated with this service provider.

public ImageInputStream

Returns:

an ImageInputStream instance.
createInputStreamInstance(Object
an object of the class type returned by getInputClass.
input)

Returns an instance of the ImageInputStream implementation associated with this service provider.

public Class<?>

Returns:

a Class variable.
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.

public boolean

Returns:

true if a cache file is needed by the input streams created by this service provider.
needsCacheFile()

Returns true if the ImageInputStream implementation associated with this service provider requires the use of a cache File.

Inherited from javax.imageio.spi.IIOServiceProvider:
getDescriptiongetVendorNamegetVersiononDeregistrationonRegistration

Field Detail

inputClassback to summary
protected Class<?> inputClass

A Class object indicating the legal object type for use by the createInputStreamInstance method.

Constructor Detail

ImageInputStreamSpiback to summary
protected ImageInputStreamSpi()

Constructs a blank 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.

ImageInputStreamSpiback to summary
public ImageInputStreamSpi(String vendorName, String version, Class<?> inputClass)

Constructs an ImageInputStreamSpi with a given set of values.

Parameters
vendorName:String

the vendor name.

version:String

a version identifier.

inputClass:Class<?>

a Class object indicating the legal object type for use by the createInputStreamInstance method.

Exceptions
IllegalArgumentException:
  • if vendorName is null.
  • if version is null.

Method Detail

canUseCacheFileback to summary
public 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. If false, the value of the useCache argument to createInputStreamInstance will be ignored.

The default implementation returns false.

Returns:boolean

true if a cache file can be used by the input streams created by this service provider.

createInputStreamInstanceback to summary
public abstract ImageInputStream createInputStreamInstance(Object input, boolean useCache, File cacheDir) throws IOException

Returns an instance of the 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.

Parameters
input:Object

an object of the class type returned by getInputClass.

useCache:boolean

a boolean indicating whether a cache file should be used, in cases where it is optional.

cacheDir:File

a File indicating where the cache file should be created, or null to use the system directory.

Returns:ImageInputStream

an ImageInputStream instance.

Exceptions
IOException:
if a cache file is needed but cannot be created.
IllegalArgumentException:
  • if input is not an instance of the correct class or is null.
  • if a cache file is needed but cacheDir is non-null and is not a directory.
See Also
getInputClass, canUseCacheFile, needsCacheFile
createInputStreamInstanceback to summary
public ImageInputStream createInputStreamInstance(Object input) throws IOException

Returns an instance of the ImageInputStream implementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed.

Parameters
input:Object

an object of the class type returned by getInputClass.

Returns:ImageInputStream

an ImageInputStream instance.

Exceptions
IOException:
if a cache file is needed but cannot be created.
IllegalArgumentException:
if input is not an instance of the correct class or is null.
See Also
getInputClass()
getInputClassback to summary
public 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.

Typical return values might include InputStream.class or URL.class, but any class may be used.

Returns:Class<?>

a Class variable.

See Also
createInputStreamInstance(Object, boolean, File)
needsCacheFileback to summary
public boolean needsCacheFile()

Returns 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.

Returns:boolean

true if a cache file is needed by the input streams created by this service provider.