public class FileCacheImageInputStream extends ImageInputStreamImpl
An implementation of ImageInputStream that gets its input from a regular InputStream. A file is used to cache previously read data.
bitOffset, byteOrder, flushedPos, streamPos public FileCacheImageInputStream(InputStream stream,
File cacheDir)
throws IOException Constructs a FileCacheImageInputStream that will read from a given InputStream.
A temporary file is used as a cache. If cacheDiris non-null and is a directory, the file will be created there. If it is null, the system-dependent default temporary-file directory will be used (see the documentation for File.createTempFile for details).
stream - an InputStream to read from.cacheDir - a File indicating where the cache file should be created, or null to use the system directory.IllegalArgumentException - if stream is null.IllegalArgumentException - if cacheDir is non-null but is not a directory.IOException - if a cache file cannot be created.public int read()
throws IOException Description copied from class: ImageInputStreamImpl
Reads a single byte from the stream and returns it as an int between 0 and 255. If EOF is reached, -1 is returned.
Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
The bit offset within the stream must be reset to zero before the read occurs.
read in interface ImageInputStream
read in class ImageInputStreamImpl
-1 if EOF is reached.IOException - if the stream has been closed.public int read(byte[] b,
int off,
int len)
throws IOException Description copied from class: ImageInputStreamImpl
Reads up to len bytes from the stream, and stores them into b starting at index off. If no bytes can be read because the end of the stream has been reached, -1 is returned.
The bit offset within the stream must be reset to zero before the read occurs.
Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.
read in interface ImageInputStream
read in class ImageInputStreamImpl
b - an array of bytes to be written to.off - the starting position within b to write to.len - the maximum number of bytes to read.-1 to indicate EOF.IOException - if an I/O error occurs.public boolean isCached()
Returns true since this ImageInputStream caches data in order to allow seeking backwards.
isCached in interface ImageInputStream
isCached in class ImageInputStreamImpl
true.isCachedMemory(), isCachedFile()
public boolean isCachedFile()
Returns true since this ImageInputStream maintains a file cache.
isCachedFile in interface ImageInputStream
isCachedFile in class ImageInputStreamImpl
true.isCached(), isCachedMemory()
public boolean isCachedMemory()
Returns false since this ImageInputStream does not maintain a main memory cache.
isCachedMemory in interface ImageInputStream
isCachedMemory in class ImageInputStreamImpl
false.isCached(), isCachedFile()
public void close()
throws IOException Closes this FileCacheImageInputStream, closing and removing the cache file. The source InputStream is not closed.
close in interface Closeable
close in interface AutoCloseable
close in interface ImageInputStream
close in class ImageInputStreamImpl
IOException - if an error occurs.protected void finalize()
throws Throwable Finalizes this object prior to garbage collection. The close method is called to close any open input source. This method should not be called from application code.
finalize in class ImageInputStreamImpl
Throwable - if an error occurs during superclass finalization.WeakReference, PhantomReference
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Documentation extracted from Debian's OpenJDK Development Kit package.
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