- java.lang.Object
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- javax.imageio.spi.IIOServiceProvider
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- javax.imageio.spi.ImageInputStreamSpi
 
 
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- All Implemented Interfaces:
- RegisterableService
 
 public abstract class ImageInputStreamSpi extends IIOServiceProvider The service provider interface (SPI) forImageInputStreams. For more information on service provider interfaces, see the class comment for theIIORegistryclass.This interface allows arbitrary objects to be "wrapped" by instances of ImageInputStream. For example, a particularImageInputStreamSpimight allow a genericInputStreamto be used as an input source; another might take input from aURL.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 ofImageInputStream(for example, native implementations for a particular platform) can be installed and used transparently by applications.- See Also:
- IIORegistry,- ImageInputStream
 
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Field SummaryFields Modifier and Type Field Description protected Class<?>inputClassAClassobject indicating the legal object type for use by thecreateInputStreamInstancemethod.- 
Fields declared in class javax.imageio.spi.IIOServiceProvidervendorName, version
 
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Constructor SummaryConstructors Modifier Constructor Description protectedImageInputStreamSpi()Constructs a blankImageInputStreamSpi.ImageInputStreamSpi(String vendorName, String version, Class<?> inputClass)Constructs anImageInputStreamSpiwith a given set of values.
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Method SummaryAll Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description booleancanUseCacheFile()Returnstrueif theImageInputStreamimplementation associated with this service provider can optionally make use of a cache file for improved performance and/or memory footrprint.ImageInputStreamcreateInputStreamInstance(Object input)Returns an instance of theImageInputStreamimplementation associated with this service provider.abstract ImageInputStreamcreateInputStreamInstance(Object input, boolean useCache, File cacheDir)Returns an instance of theImageInputStreamimplementation associated with this service provider.Class<?>getInputClass()Returns aClassobject representing the class or interface type that must be implemented by an input source in order to be "wrapped" in anImageInputStreamvia thecreateInputStreamInstancemethod.booleanneedsCacheFile()Returnstrueif theImageInputStreamimplementation associated with this service provider requires the use of a cacheFile.- 
Methods declared in class javax.imageio.spi.IIOServiceProvidergetDescription, getVendorName, getVersion, onDeregistration, onRegistration
 
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Field Detail- 
inputClassprotected Class<?> inputClass AClassobject indicating the legal object type for use by thecreateInputStreamInstancemethod.
 
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Constructor Detail- 
ImageInputStreamSpiprotected ImageInputStreamSpi() Constructs a blankImageInputStreamSpi. It is up to the subclass to initialize instance variables and/or override method implementations in order to provide working versions of all methods.
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ImageInputStreamSpipublic ImageInputStreamSpi(String vendorName, String version, Class<?> inputClass) Constructs anImageInputStreamSpiwith a given set of values.- Parameters:
- vendorName- the vendor name.
- version- a version identifier.
- inputClass- a- Classobject indicating the legal object type for use by the- createInputStreamInstancemethod.
- Throws:
- IllegalArgumentException- if- vendorNameis- null.
- IllegalArgumentException- if- versionis- null.
 
 
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Method Detail- 
getInputClasspublic Class<?> getInputClass() Returns aClassobject representing the class or interface type that must be implemented by an input source in order to be "wrapped" in anImageInputStreamvia thecreateInputStreamInstancemethod.Typical return values might include InputStream.classorURL.class, but any class may be used.- Returns:
- a Classvariable.
- See Also:
- createInputStreamInstance(Object, boolean, File)
 
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canUseCacheFilepublic boolean canUseCacheFile() Returnstrueif theImageInputStreamimplementation associated with this service provider can optionally make use of a cache file for improved performance and/or memory footrprint. Iffalse, the value of theuseCacheargument tocreateInputStreamInstancewill be ignored.The default implementation returns false.- Returns:
- trueif a cache file can be used by the input streams created by this service provider.
 
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needsCacheFilepublic boolean needsCacheFile() Returnstrueif theImageInputStreamimplementation associated with this service provider requires the use of a cacheFile. Iftrue, the value of theuseCacheargument tocreateInputStreamInstancewill be ignored.The default implementation returns false.- Returns:
- trueif a cache file is needed by the input streams created by this service provider.
 
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createInputStreamInstancepublic abstract ImageInputStream createInputStreamInstance(Object input, boolean useCache, File cacheDir) throws IOException Returns an instance of theImageInputStreamimplementation associated with this service provider. If the use of a cache file is optional, theuseCacheparameter will be consulted. Where a cache is required, or not applicable, the value ofuseCachewill be ignored.- Parameters:
- input- an object of the class type returned by- getInputClass.
- useCache- a- booleanindicating whether a cache file should be used, in cases where it is optional.
- cacheDir- a- Fileindicating where the cache file should be created, or- nullto use the system directory.
- Returns:
- an ImageInputStreaminstance.
- Throws:
- IllegalArgumentException- if- inputis not an instance of the correct class or is- null.
- IllegalArgumentException- if a cache file is needed but- cacheDiris non-- nulland is not a directory.
- IOException- if a cache file is needed but cannot be created.
- See Also:
- getInputClass(),- canUseCacheFile(),- needsCacheFile()
 
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createInputStreamInstancepublic ImageInputStream createInputStreamInstance(Object input) throws IOException Returns an instance of theImageInputStreamimplementation associated with this service provider. A cache file will be created in the system-dependent default temporary-file directory, if needed.- Parameters:
- input- an object of the class type returned by- getInputClass.
- Returns:
- an ImageInputStreaminstance.
- Throws:
- IllegalArgumentException- if- inputis not an instance of the correct class or is- null.
- IOException- if a cache file is needed but cannot be created.
- See Also:
- getInputClass()
 
 
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