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
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(OutputStreamstream)
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.
write in interface
DataOutput
write in interface
ImageOutputStream
write in class
ImageOutputStreamImpl
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.
write in interface
DataOutput
write in interface
ImageOutputStream
write in class
ImageOutputStreamImpl
b - 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
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.
isCachedMemory(),
isCachedFile()
public boolean isCachedFile()
false since this
ImageOutputStream does not maintain a file cache.
isCachedFile in interface
ImageInputStream
isCachedFile in class
ImageInputStreamImpl
false.
isCached(),
isCachedMemory()
public boolean isCachedMemory()
true since this
ImageOutputStream maintains a main memory cache.
isCachedMemory in interface
ImageInputStream
isCachedMemory in class
ImageInputStreamImpl
true.
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
Closeable
close in interface
AutoCloseable
close in interface
ImageInputStream
close in class
ImageInputStreamImpl
IOException - if an I/O error occurs.
public void flushBefore(long pos)
throws IOException
ImageInputStream
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.
flushBefore in interface
ImageInputStream
flushBefore in interface
ImageOutputStream
flushBefore in class
ImageInputStreamImpl
pos - a
long containing the length of the stream prefix that may be flushed.
IOException - if an I/O error occurs.