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JavaTM 2 Platform Standard Ed. 5.0 |
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java.lang.Objectjavax.imageio.stream.ImageInputStreamImpl
javax.imageio.stream.ImageOutputStreamImpl
javax.imageio.stream.MemoryCacheImageOutputStream
public class 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.
| Field Summary |
|---|
| Fields inherited from class javax.imageio.stream.ImageInputStreamImpl |
|---|
bitOffset, byteOrder, flushedPos, streamPos |
| Constructor Summary | |
|---|---|
MemoryCacheImageOutputStream(OutputStream stream)
Constructs a MemoryCacheImageOutputStream that will write
to a given OutputStream. |
|
| Method Summary | |
|---|---|
void |
close()
Closes this MemoryCacheImageOutputStream. |
void |
flushBefore(long pos)
Discards the initial portion of the stream prior to the indicated postion. |
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 integer 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 len bytes from array
b, in order, to
the output stream. |
void |
write(int b)
Writes to the output stream the eight low-order bits of the argument b. |
| Methods inherited from class javax.imageio.stream.ImageOutputStreamImpl |
|---|
flushBits, write, writeBit, writeBits, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeChars, writeDouble, writeDoubles, writeFloat, writeFloats, writeInt, writeInts, writeLong, writeLongs, writeShort, writeShorts, writeUTF |
| Methods inherited from class javax.imageio.stream.ImageInputStreamImpl |
|---|
checkClosed, 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, skipBytes |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Methods inherited from interface javax.imageio.stream.ImageInputStream |
|---|
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 |
| Constructor Detail |
|---|
public MemoryCacheImageOutputStream(OutputStream stream)
MemoryCacheImageOutputStream that will write
to a given OutputStream.
stream - an OutputStream to write to.
IllegalArgumentException - if stream is
null.| Method Detail |
|---|
public int read()
throws IOException
ImageInputStreamThe bit offset within the stream is reset to zero before the read occurs.
read in interface ImageInputStreamread in class ImageInputStreamImplIOException - if an I/O error occurs.
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
DataOutputb.
The 24 high-order bits of b
are ignored.
write in interface DataOutputwrite in interface ImageOutputStreamwrite in class ImageOutputStreamImplb - the byte to be written.
IOException - if an I/O error occurs.
public void write(byte[] b,
int off,
int len)
throws IOException
DataOutputlen bytes from array
b, in order, to
the output stream. If b
is null, a NullPointerException
is thrown. If off is negative,
or len is negative, or off+len
is greater than the length of the array
b, then an IndexOutOfBoundsException
is thrown. If len is zero,
then no bytes are written. Otherwise, the
byte b[off] is written first,
then b[off+1], and so on; the
last byte written is b[off+len-1].
write in interface DataOutputwrite in interface ImageOutputStreamwrite in class ImageOutputStreamImplb - the data.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 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
file prefix that may be flushed.
IOException - if an I/O error occurs.
|
JavaTM 2 Platform Standard Ed. 5.0 |
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Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.