Class FilterOutputStream

lib/java/io/FilterOutputStream.java:33–154

Wraps an existing OutputStream and performs some transformation on the output data while it is being written. Transformations can be anything from a simple byte-wise filtering output data to an on-the-fly compression or decompression of the underlying stream. Output streams that wrap another

 * @see FilterOutputStream
 */
public class FilterOutputStream extends OutputStream {

    /**
     * The target output stream for this filter stream.
     */
    protected OutputStream out;

    /**
     * Constructs a new {@code FilterOutputStream} with {@code out} as its
     * target stream.
     * 
     * @param out
     *            the target stream that this stream writes to.
     */
    public FilterOutputStream(OutputStream out) {
        this.out = out;
    }

    /**
     * Closes this stream. This implementation closes the target stream.
     * 
     * @throws IOException
     *             if an error occurs attempting to close this stream.
     */
    @Override
    public void close() throws IOException {
        Throwable thrown = null;
        try {
            flush();
        } catch (Throwable e) {
            thrown = e;
        }

        try {
            out.close();
        } catch (Throwable e) {
            if (thrown == null) {
                thrown = e;
            }
        }

        if (thrown != null) {
            SneakyThrow.sneakyThrow(thrown);
        }
    }

    /**
     * Ensures that all pending data is sent out to the target stream. This
     * implementation flushes the target stream.
     * 
     * @throws IOException
     *             if an error occurs attempting to flush this stream.
     */
    @Override
    public void flush() throws IOException {
        out.flush();
    }