Closeable
, DataInput
, DataOutput
, AutoCloseable
, ImageInputStream
, ImageOutputStream
public class MemoryCacheImageOutputStream extends ImageOutputStreamImpl
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.bitOffset, byteOrder, flushedPos, streamPos
Constructor | Description |
---|---|
MemoryCacheImageOutputStream |
Constructs a MemoryCacheImageOutputStream that will write to a given OutputStream . |
Modifier and Type | Method | Description |
---|---|---|
void |
close() |
Closes this MemoryCacheImageOutputStream . |
void |
flushBefore |
Flushes all data prior to the given position to the underlying destination, such as an OutputStream or File . |
boolean |
isCached() |
Returns true since this ImageOutputStream caches data in order to allow seeking backwards. |
boolean |
isCachedFile() |
Returns false since this ImageOutputStream does not maintain a file cache. |
boolean |
isCachedMemory() |
Returns true since this ImageOutputStream maintains a main memory cache. |
long |
length() |
Returns -1L to indicate that the stream has unknown length. |
int |
read() |
Reads a single byte from the stream and returns it as an int between 0 and 255. |
int |
read |
Reads up to len bytes from the stream, and stores them into b starting at index off . |
void |
write |
Writes a sequence of bytes to the stream at the current position. |
void |
write |
Writes a single byte to the stream at the current position. |
flushBits, write, writeBit, writeBits, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeChars, writeDouble, writeDoubles, writeFloat, writeFloats, writeInt, writeInts, writeLong, writeLongs, writeShort, writeShorts, writeUTF
checkClosed, finalize, 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
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
flush, getBitOffset, getByteOrder, getFlushedPosition, getStreamPosition, 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
public MemoryCacheImageOutputStream(OutputStream stream)
MemoryCacheImageOutputStream
that will write to a given OutputStream
.stream
- an OutputStream
to write to.IllegalArgumentException
- if stream
is null
.public int read() throws IOException
ImageInputStreamImpl
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
ImageInputStreamImpl
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 void write(int b) throws IOException
ImageOutputStream
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 flushBits
method of ImageOutputStreamImpl
to guarantee this.
b
- an int
whose lower 8 bits are to be written.IOException
- if an I/O error occurs.public void write(byte[] b, int off, int len) throws IOException
ImageOutputStream
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 flushBits
method of ImageOutputStreamImpl
to guarantee this.
b
- an array of byte
s to be written.off
- the start offset in the data.len
- the number of byte
s to write.IOException
- if an I/O error occurs.public long length()
ImageInputStreamImpl
-1L
to indicate that the stream has unknown length. Subclasses must override this method to provide actual length information.length
in interface ImageInputStream
length
in class ImageInputStreamImpl
public boolean isCached()
true
since this ImageOutputStream
caches data in order to allow seeking backwards.isCached
in interface ImageInputStream
isCached
in class ImageInputStreamImpl
true
.public boolean isCachedFile()
false
since this ImageOutputStream
does not maintain a file cache.isCachedFile
in interface ImageInputStream
isCachedFile
in class ImageInputStreamImpl
false
.public boolean isCachedMemory()
true
since this ImageOutputStream
maintains a main memory cache.isCachedMemory
in interface ImageInputStream
isCachedMemory
in class ImageInputStreamImpl
true
.public void close() throws IOException
MemoryCacheImageOutputStream
. All pending data is flushed to the output, and the cache is released. The destination OutputStream
is not closed.IOException
- if an I/O error occurs.public void flushBefore(long pos) throws IOException
ImageOutputStream
OutputStream
or File
. Attempting to seek to the flushed portion of the stream will result in an IndexOutOfBoundsException
.pos
- a long
containing the length of the stream prefix that may be flushed to the destination.IOException
- if an I/O error occurs.
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/imageio/stream/MemoryCacheImageOutputStream.html