Closeable, DataInput, DataOutput, AutoCloseable, ImageInputStream, ImageOutputStream
public class FileCacheImageOutputStream extends ImageOutputStreamImpl
ImageOutputStream that writes its output to a regular OutputStream. A file is used to cache data until it is flushed to the output stream.bitOffset, byteOrder, flushedPos, streamPos
| Constructor | Description |
|---|---|
FileCacheImageOutputStream |
Constructs a FileCacheImageOutputStream that will write to a given outputStream. |
| Modifier and Type | Method | Description |
|---|---|---|
void |
close() |
Closes this FileCacheImageOutputStream. |
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 true since this ImageOutputStream maintains a file cache. |
boolean |
isCachedMemory() |
Returns false since this ImageOutputStream does not maintain 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 |
seek |
Sets the current stream position and resets the bit offset to 0. |
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, 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, setBitOffset, setByteOrder, skipBytes, skipBytes
public FileCacheImageOutputStream(OutputStream stream, File cacheDir) throws IOException
FileCacheImageOutputStream that will write to a given outputStream. A temporary file is used as a cache. If cacheDir is non-null and is a directory, the file will be created there. If it is null, the system-dependent default temporary-file directory will be used (see the documentation for File.createTempFile for details).
stream - an OutputStream to write to.cacheDir - a File indicating where the cache file should be created, or null to use the system directory.IllegalArgumentException - if stream is null.IllegalArgumentException - if cacheDir is non-null but is not a directory.IOException - if a cache file cannot be created.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 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
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 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
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.
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
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.
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 void seek(long pos) throws IOException
EOFException will be thrown only if a read is performed. The file length will not be increased until a write is performed.pos - a long containing the desired file pointer position.IndexOutOfBoundsException - if pos is smaller than the flushed position.IOException - if any other I/O error occurs.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()
true since this ImageOutputStream maintains a file cache.isCachedFile in interface ImageInputStream
isCachedFile in class ImageInputStreamImpl
true.public boolean isCachedMemory()
false since this ImageOutputStream does not maintain a main memory cache.isCachedMemory in interface ImageInputStream
isCachedMemory in class ImageInputStreamImpl
false.public void close() throws IOException
FileCacheImageOutputStream. All pending data is flushed to the output, and the cache file is closed and removed. The destination OutputStream is not closed.IOException - if an error occurs.public void flushBefore(long pos) throws IOException
ImageOutputStreamOutputStream 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.
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/imageio/stream/FileCacheImageOutputStream.html