Class FileCacheImageInputStream
java.lang.Object
javax.imageio.stream.ImageInputStreamImpl
javax.imageio.stream.FileCacheImageInputStream
- All Implemented Interfaces:
Closeable,DataInput,AutoCloseable,ImageInputStream
An implementation of
ImageInputStream that gets its
input from a regular InputStream. A file is used to
cache previously read data.-
Field Summary
Fields declared in class javax.imageio.stream.ImageInputStreamImpl
bitOffset, byteOrder, flushedPos, streamPos -
Constructor Summary
ConstructorsConstructorDescriptionFileCacheImageInputStream(InputStream stream, File cacheDir) Constructs aFileCacheImageInputStreamthat will read from a givenInputStream. -
Method Summary
Modifier and TypeMethodDescriptionvoidclose()Closes thisFileCacheImageInputStream, closing and removing the cache file.protected voidfinalize()Deprecated, for removal: This API element is subject to removal in a future version.Finalization has been deprecated for removal.booleanisCached()Returnstruesince thisImageInputStreamcaches data in order to allow seeking backwards.booleanReturnstruesince thisImageInputStreammaintains a file cache.booleanReturnsfalsesince thisImageInputStreamdoes not maintain a main memory cache.intread()Reads a single byte from the stream and returns it as anintbetween 0 and 255.intread(byte[] b, int off, int len) Reads up tolenbytes from the stream, and stores them intobstarting at indexoff.Methods declared in class javax.imageio.stream.ImageInputStreamImpl
checkClosed, flush, flushBefore, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, length, mark, read, readBit, readBits, readBoolean, readByte, readBytes, readChar, readDouble, readFloat, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedInt, readUnsignedShort, readUTF, reset, seek, setBitOffset, setByteOrder, skipBytes, skipBytes
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Constructor Details
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FileCacheImageInputStream
Constructs aFileCacheImageInputStreamthat will read from a givenInputStream.A temporary file is used as a cache. If
cacheDiris non-nulland is a directory, the file will be created there. If it isnull, the system-dependent default temporary-file directory will be used (see the documentation forFile.createTempFilefor details).- Parameters:
stream- anInputStreamto read from.cacheDir- aFileindicating where the cache file should be created, ornullto use the system directory.- Throws:
IllegalArgumentException- ifstreamisnull.IllegalArgumentException- ifcacheDiris non-nullbut is not a directory.IOException- if a cache file cannot be created.
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Method Details
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read
Description copied from class:ImageInputStreamImplReads a single byte from the stream and returns it as anintbetween 0 and 255. If EOF is reached,-1is 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.
- Specified by:
readin interfaceImageInputStream- Specified by:
readin classImageInputStreamImpl- Returns:
- the value of the next byte in the stream, or
-1if EOF is reached. - Throws:
IOException- if the stream has been closed.
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read
Description copied from class:ImageInputStreamImplReads up tolenbytes from the stream, and stores them intobstarting at indexoff. If no bytes can be read because the end of the stream has been reached,-1is 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.
- Specified by:
readin interfaceImageInputStream- Specified by:
readin classImageInputStreamImpl- Parameters:
b- an array of bytes to be written to.off- the starting position withinbto write to.len- the maximum number of bytes to read.- Returns:
- the number of bytes actually read, or
-1to indicate EOF. - Throws:
IOException- if an I/O error occurs.
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isCached
public boolean isCached()Returnstruesince thisImageInputStreamcaches data in order to allow seeking backwards.- Specified by:
isCachedin interfaceImageInputStream- Overrides:
isCachedin classImageInputStreamImpl- Returns:
true.- See Also:
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isCachedFile
public boolean isCachedFile()Returnstruesince thisImageInputStreammaintains a file cache.- Specified by:
isCachedFilein interfaceImageInputStream- Overrides:
isCachedFilein classImageInputStreamImpl- Returns:
true.- See Also:
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isCachedMemory
public boolean isCachedMemory()Returnsfalsesince thisImageInputStreamdoes not maintain a main memory cache.- Specified by:
isCachedMemoryin interfaceImageInputStream- Overrides:
isCachedMemoryin classImageInputStreamImpl- Returns:
false.- See Also:
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close
Closes thisFileCacheImageInputStream, closing and removing the cache file. The sourceInputStreamis not closed.- Throws:
IOException- if an error occurs.
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finalize
Deprecated, for removal: This API element is subject to removal in a future version.Finalization has been deprecated for removal. SeeObject.finalize()for background information and details about migration options.Finalizes this object prior to garbage collection. Theclosemethod is called to close any open input source. This method should not be called from application code.- Overrides:
finalizein classImageInputStreamImpl- Throws:
Throwable- if an error occurs during superclass finalization.- See Also:
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