Class FileCacheImageOutputStream

public FileCacheImageOutputStream(OutputStream stream, File cacheDir) throws IOException

Constructs a 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).

public int read() throws IOException

Reads a single byte from the stream and returns it as an 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.

public int read(byte[] b, int off, int len) throws IOException

Reads up to 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.

public void write(int b) throws IOException

Writes a single byte to the stream at the current position. The 24 high-order bits of 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.

public void write(byte[] b, int off, int len) throws IOException

Writes a sequence of bytes to the stream at the current position. If 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.

public long length()

Returns -1L to indicate that the stream has unknown length. Subclasses must override this method to provide actual length information.

public void seek(long pos) throws IOException

Sets the current stream position and resets the bit offset to 0. It is legal to seek past the end of the file; an EOFException will be thrown only if a read is performed. The file length will not be increased until a write is performed.

public boolean isCached()

Returns true since this ImageOutputStream caches data in order to allow seeking backwards.

public boolean isCachedFile()

Returns true since this ImageOutputStream maintains a file cache.

public boolean isCachedMemory()

Returns false since this ImageOutputStream does not maintain a main memory cache.

public void close() throws IOException

Closes this FileCacheImageOutputStream. All pending data is flushed to the output, and the cache file is closed and removed. The destination OutputStream is not closed.

public void flushBefore(long pos) throws IOException

Flushes all data prior to the given position to the underlying destination, such as an OutputStream or File. Attempting to seek to the flushed portion of the stream will result in an IndexOutOfBoundsException.