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
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Constructor Summary
ConstructorDescriptionFileCacheImageInputStream
(InputStream stream, File cacheDir) Constructs aFileCacheImageInputStream
that will read from a givenInputStream
. -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Closes thisFileCacheImageInputStream
, closing and removing the cache file.protected void
finalize()
Deprecated, for removal: This API element is subject to removal in a future version.Finalization has been deprecated for removal.boolean
isCached()
Returnstrue
since thisImageInputStream
caches data in order to allow seeking backwards.boolean
Returnstrue
since thisImageInputStream
maintains a file cache.boolean
Returnsfalse
since thisImageInputStream
does not maintain a main memory cache.int
read()
Reads a single byte from the stream and returns it as anint
between 0 and 255.int
read
(byte[] b, int off, int len) Reads up tolen
bytes from the stream, and stores them intob
starting 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
-
FileCacheImageInputStream
Constructs aFileCacheImageInputStream
that will read from a givenInputStream
.A temporary file is used as a cache. If
cacheDir
is non-null
and 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.createTempFile
for details).- Parameters:
stream
- anInputStream
to read from.cacheDir
- aFile
indicating where the cache file should be created, ornull
to use the system directory.- Throws:
IllegalArgumentException
- ifstream
isnull
.IllegalArgumentException
- ifcacheDir
is non-null
but is not a directory.IOException
- if a cache file cannot be created.
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Method Details
-
read
Description copied from class:ImageInputStreamImpl
Reads a single byte from the stream and returns it as anint
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.
- Specified by:
read
in interfaceImageInputStream
- Specified by:
read
in classImageInputStreamImpl
- Returns:
- the value of the next byte in the stream, or
-1
if EOF is reached. - Throws:
IOException
- if the stream has been closed.
-
read
Description copied from class:ImageInputStreamImpl
Reads up tolen
bytes from the stream, and stores them intob
starting at indexoff
. 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.
- Specified by:
read
in interfaceImageInputStream
- Specified by:
read
in classImageInputStreamImpl
- Parameters:
b
- an array of bytes to be written to.off
- the starting position withinb
to write to.len
- the maximum number of bytes to read.- Returns:
- the number of bytes actually read, or
-1
to indicate EOF. - Throws:
IOException
- if an I/O error occurs.
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isCached
public boolean isCached()Returnstrue
since thisImageInputStream
caches data in order to allow seeking backwards.- Specified by:
isCached
in interfaceImageInputStream
- Overrides:
isCached
in classImageInputStreamImpl
- Returns:
true
.- See Also:
-
isCachedFile
public boolean isCachedFile()Returnstrue
since thisImageInputStream
maintains a file cache.- Specified by:
isCachedFile
in interfaceImageInputStream
- Overrides:
isCachedFile
in classImageInputStreamImpl
- Returns:
true
.- See Also:
-
isCachedMemory
public boolean isCachedMemory()Returnsfalse
since thisImageInputStream
does not maintain a main memory cache.- Specified by:
isCachedMemory
in interfaceImageInputStream
- Overrides:
isCachedMemory
in classImageInputStreamImpl
- Returns:
false
.- See Also:
-
close
Closes thisFileCacheImageInputStream
, closing and removing the cache file. The sourceInputStream
is 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. Theclose
method is called to close any open input source. This method should not be called from application code.- Overrides:
finalize
in classImageInputStreamImpl
- Throws:
Throwable
- if an error occurs during superclass finalization.- See Also:
-