
 
        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.
        
        
Returns:
    an 
ImageInputStream instance. 
Parameters:
 - 
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.
Throws:
  - 
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.
See Also:
  ImageInputStreamSpi.getInputClass(), 
  
ImageInputStreamSpi.canUseCacheFile(), 
  
ImageInputStreamSpi.needsCacheFile(),