java.lang.Object | |||
↳ | javax.imageio.stream.ImageInputStreamImpl | ||
↳ | javax.imageio.stream.ImageOutputStreamImpl | ||
↳ | javax.imageio.stream.MemoryCacheImageOutputStream |
An implementation of ImageOutputStream
that writes its
output to a regular OutputStream
. A memory buffer is
used to cache at least the data between the discard position and
the current write position. The only constructor takes an
OutputStream
, so this class may not be used for
read/modify/write operations. Reading can occur only on parts of
the stream that have already been written to the cache and not
yet flushed.
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Inherited Fields | |||||||||||
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Public Constructors | |||||||||||
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Constructs a
MemoryCacheImageOutputStream that will write
to a given OutputStream . |
Public Methods | |||||||||||
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Closes this
MemoryCacheImageOutputStream . | |||||||||||
Discards the initial portion of the stream prior to the
indicated postion.
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Returns
true since this
ImageOutputStream caches data in order to allow
seeking backwards. | |||||||||||
Returns
false since this
ImageOutputStream does not maintain a file cache. | |||||||||||
Returns
true since this
ImageOutputStream maintains a main memory cache. | |||||||||||
Returns
-1L to indicate that the stream has unknown
length. | |||||||||||
Reads a single byte from the stream and returns it as an
int between 0 and 255. | |||||||||||
Reads up to
len bytes from the stream, and stores
them into b starting at index off . | |||||||||||
Writes a sequence of bytes to the stream at the current
position.
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Writes a single byte to the stream at the current position.
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Constructs a MemoryCacheImageOutputStream
that will write
to a given OutputStream
.
stream | an OutputStream to write to. |
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IllegalArgumentException | if stream is
null .
|
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Closes this MemoryCacheImageOutputStream
. All
pending data is flushed to the output, and the cache
is released. The destination OutputStream
is not closed.
IOException |
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Discards the initial portion of the stream prior to the
indicated postion. Attempting to seek to an offset within the
flushed portion of the stream will result in an
IndexOutOfBoundsException
.
Calling flushBefore
may allow classes
implementing this interface to free up resources such as memory
or disk space that are being used to store data from the
stream.
pos | a long containing the length of the
stream prefix that may be flushed. |
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IOException |
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Returns true
since this
ImageOutputStream
caches data in order to allow
seeking backwards.
true
.Returns false
since this
ImageOutputStream
does not maintain a file cache.
false
.Returns true
since this
ImageOutputStream
maintains a main memory cache.
true
.Returns -1L
to indicate that the stream has unknown
length. Subclasses must override this method to provide actual
length information.
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.
-1
if EOF is reached.IOException |
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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.
b | an array of bytes to be written to. |
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off | the starting position within b to write to. |
len | the maximum number of bytes to read. |
-1
to indicate EOF.IOException |
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Writes a sequence of bytes to the stream at the current
position. If len
is 0, nothing is written.
The byte b[off]
is written first, then the byte
b[off + 1]
, and so on.
If the bit offset within the stream is non-zero, the
remainder of the current byte is padded with 0s
and written out first. The bit offset will be 0 after the
write. Implementers can use the
method of flushBits
to guarantee this.ImageOutputStreamImpl
b | an array of byte s to be written. |
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off | the start offset in the data. |
len | the number of byte s to write. |
IOException |
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Writes a single byte to the stream at the current position.
The 24 high-order bits of b
are ignored.
If the bit offset within the stream is non-zero, the
remainder of the current byte is padded with 0s
and written out first. The bit offset will be 0 after the
write. Implementers can use the
method of flushBits
to guarantee this.ImageOutputStreamImpl
b | an int whose lower 8 bits are to be
written. |
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IOException |
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