- * It is mostly intended to be used as a base class to create new - * {@link OutputStream}s with special operation modes, and to give some default - * methods. - * - * @author niki - */ -public class BufferedOutputStream extends OutputStream { - /** The current position in the buffer. */ - protected int start; - /** The index of the last usable position of the buffer. */ - protected int stop; - /** The buffer itself. */ - protected byte[] buffer; - /** An End-Of-File (or buffer, here) marker. */ - protected boolean eof; - /** The actual under-laying stream. */ - protected OutputStream out; - /** The number of bytes written to the under-laying stream. */ - protected long bytesWritten; - /** - * Can bypass the flush process for big writes (will directly write to the - * under-laying buffer if the array to write is > the internal buffer - * size). - *
- * By default, this is true. - */ - protected boolean bypassFlush = true; - - private boolean closed; - private int openCounter; - private byte[] b1; - - /** - * Create a new {@link BufferedInputStream} that wraps the given - * {@link InputStream}. - * - * @param out - * the {@link OutputStream} to wrap - */ - public BufferedOutputStream(OutputStream out) { - this.out = out; - - this.buffer = new byte[4096]; - this.b1 = new byte[1]; - this.start = 0; - this.stop = 0; - } - - @Override - public void write(int b) throws IOException { - b1[0] = (byte) b; - write(b1, 0, 1); - } - - @Override - public void write(byte[] b) throws IOException { - write(b, 0, b.length); - } - - @Override - public void write(byte[] source, int sourceOffset, int sourceLength) - throws IOException { - - checkClose(); - - if (source == null) { - throw new NullPointerException(); - } else if ((sourceOffset < 0) || (sourceOffset > source.length) - || (sourceLength < 0) - || ((sourceOffset + sourceLength) > source.length) - || ((sourceOffset + sourceLength) < 0)) { - throw new IndexOutOfBoundsException(); - } else if (sourceLength == 0) { - return; - } - - if (bypassFlush && sourceLength >= buffer.length) { - /* - * If the request length exceeds the size of the output buffer, - * flush the output buffer and then write the data directly. In this - * way buffered streams will cascade harmlessly. - */ - flush(false); - out.write(source, sourceOffset, sourceLength); - bytesWritten += (sourceLength - sourceOffset); - return; - } - - int done = 0; - while (done < sourceLength) { - if (available() <= 0) { - flush(false); - } - - int now = Math.min(sourceLength - done, available()); - System.arraycopy(source, sourceOffset + done, buffer, stop, now); - stop += now; - done += now; - } - } - - /** - * The available space in the buffer. - * - * @return the space in bytes - */ - private int available() { - if (closed) { - return 0; - } - - return Math.max(0, buffer.length - stop - 1); - } - - /** - * The number of bytes written to the under-laying {@link OutputStream}. - * - * @return the number of bytes - */ - public long getBytesWritten() { - return bytesWritten; - } - - /** - * Return this very same {@link BufferedInputStream}, but keep a counter of - * how many streams were open this way. When calling - * {@link BufferedInputStream#close()}, decrease this counter if it is not - * already zero instead of actually closing the stream. - *
- * You are now responsible for it — you must close it. - *
- * This method allows you to use a wrapping stream around this one and still - * close the wrapping stream. - * - * @return the same stream, but you are now responsible for closing it - * - * @throws IOException - * in case of I/O error or if the stream is closed - */ - public synchronized OutputStream open() throws IOException { - checkClose(); - openCounter++; - return this; - } - - /** - * Check that the stream was not closed, and throw an {@link IOException} if - * it was. - * - * @throws IOException - * if it was closed - */ - protected void checkClose() throws IOException { - if (closed) { - throw new IOException( - "This BufferedInputStream was closed, you cannot use it anymore."); - } - } - - @Override - public void flush() throws IOException { - flush(true); - } - - /** - * Flush the {@link BufferedOutputStream}, write the current buffered data - * to (and optionally also flush) the under-laying stream. - *
- * If {@link BufferedOutputStream#bypassFlush} is false, all writes to the - * under-laying stream are done in this method. - *
- * This can be used if you want to write some data in the under-laying - * stream yourself (in that case, flush this {@link BufferedOutputStream} - * with or without flushing the under-laying stream, then you can write to - * the under-laying stream). - * - * @param includingSubStream - * also flush the under-laying stream - * @throws IOException - * in case of I/O error - */ - public void flush(boolean includingSubStream) throws IOException { - if (stop > start) { - out.write(buffer, start, stop - start); - bytesWritten += (stop - start); - } - start = 0; - stop = 0; - - if (includingSubStream) { - out.flush(); - } - } - - /** - * Closes this stream and releases any system resources associated with the - * stream. - *
- * Including the under-laying {@link InputStream}. - *
- * Note: if you called the {@link BufferedInputStream#open()} method - * prior to this one, it will just decrease the internal count of how many - * open streams it held and do nothing else. The stream will actually be - * closed when you have called {@link BufferedInputStream#close()} once more - * than {@link BufferedInputStream#open()}. - * - * @exception IOException - * in case of I/O error - */ - @Override - public synchronized void close() throws IOException { - close(true); - } - - /** - * Closes this stream and releases any system resources associated with the - * stream. - *
- * Including the under-laying {@link InputStream} if - * incudingSubStream is true. - *
- * You can call this method multiple times, it will not cause an - * {@link IOException} for subsequent calls. - *
- * Note: if you called the {@link BufferedInputStream#open()} method - * prior to this one, it will just decrease the internal count of how many - * open streams it held and do nothing else. The stream will actually be - * closed when you have called {@link BufferedInputStream#close()} once more - * than {@link BufferedInputStream#open()}. - * - * @param includingSubStream - * also close the under-laying stream - * - * @exception IOException - * in case of I/O error - */ - public synchronized void close(boolean includingSubStream) - throws IOException { - if (!closed) { - if (openCounter > 0) { - openCounter--; - } else { - closed = true; - flush(includingSubStream); - if (includingSubStream && out != null) { - out.close(); - } - } - } - } -}