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 and Description |
|---|
MemoryCacheImageOutputStream(OutputStream stream)
Constructs a
MemoryCacheImageOutputStream that will write
to a given OutputStream. |
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Closes this
MemoryCacheImageOutputStream. |
void |
flushBefore(long pos)
Discards the initial portion of the stream prior to the
indicated position.
|
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(byte[] b,
int off,
int len)
Reads up to
len bytes from the stream, and stores
them into b starting at index off. |
void |
write(byte[] b,
int off,
int len)
Writes a sequence of bytes to the stream at the current
position.
|
void |
write(int b)
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, writeUTFcheckClosed, finalize, 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, skipBytesclone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitflush, 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, skipBytespublic 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
ImageInputStreamImplint 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 ImageInputStreamread 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
ImageInputStreamImpllen 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 ImageInputStreamread in class ImageInputStreamImplb - 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
ImageOutputStreamb 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.
write in interface DataOutputwrite in interface ImageOutputStreamwrite in class ImageOutputStreamImplb - 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
ImageOutputStreamlen 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.
write in interface DataOutputwrite in interface ImageOutputStreamwrite in class ImageOutputStreamImplb - an array of bytes to be written.off - the start offset in the data.len - the number of bytes 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 ImageInputStreamlength in class ImageInputStreamImplpublic boolean isCached()
true since this
ImageOutputStream caches data in order to allow
seeking backwards.isCached in interface ImageInputStreamisCached in class ImageInputStreamImpltrue.isCachedMemory(),
isCachedFile()public boolean isCachedFile()
false since this
ImageOutputStream does not maintain a file cache.isCachedFile in interface ImageInputStreamisCachedFile in class ImageInputStreamImplfalse.isCached(),
isCachedMemory()public boolean isCachedMemory()
true since this
ImageOutputStream maintains a main memory cache.isCachedMemory in interface ImageInputStreamisCachedMemory in class ImageInputStreamImpltrue.isCached(),
isCachedFile()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.close in interface Closeableclose in interface AutoCloseableclose in interface ImageInputStreamclose in class ImageInputStreamImplIOException - if an I/O error occurs.public void flushBefore(long pos)
throws IOException
ImageInputStreamIndexOutOfBoundsException.
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.
flushBefore in interface ImageInputStreamflushBefore in interface ImageOutputStreamflushBefore in class ImageInputStreamImplpos - a long containing the length of the
stream prefix that may be flushed.IOException - if an I/O error occurs. Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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