- * The separation in sub-streams is done via {@link NextableInputStreamStep}. - * - * @author niki - */ -public class NextableInputStream extends BufferedInputStream { - private NextableInputStreamStep step; - private boolean started; - private boolean stopped; - - /** - * Create a new {@link NextableInputStream} that wraps the given - * {@link InputStream}. - * - * @param in - * the {@link InputStream} to wrap - * @param step - * how to separate it into sub-streams (can be NULL, but in that - * case it will behave as a normal {@link InputStream}) - */ - public NextableInputStream(InputStream in, NextableInputStreamStep step) { - super(in); - this.step = step; - } - - /** - * Create a new {@link NextableInputStream} that wraps the given bytes array - * as a data source. - * - * @param in - * the array to wrap, cannot be NULL - * @param step - * how to separate it into sub-streams (can be NULL, but in that - * case it will behave as a normal {@link InputStream}) - */ - public NextableInputStream(byte[] in, NextableInputStreamStep step) { - this(in, step, 0, in.length); - } - - /** - * Create a new {@link NextableInputStream} that wraps the given bytes array - * as a data source. - * - * @param in - * the array to wrap, cannot be NULL - * @param step - * how to separate it into sub-streams (can be NULL, but in that - * case it will behave as a normal {@link InputStream}) - * @param offset - * the offset to start the reading at - * @param length - * the number of bytes to take into account in the array, - * starting from the offset - * - * @throws NullPointerException - * if the array is NULL - * @throws IndexOutOfBoundsException - * if the offset and length do not correspond to the given array - */ - public NextableInputStream(byte[] in, NextableInputStreamStep step, - int offset, int length) { - super(in, offset, length); - this.step = step; - checkBuffer(true); - } - - /** - * Unblock the processing of the next sub-stream. - *
- * It can only be called when the "current" stream is spent (i.e., you must - * first process the stream until it is spent). - *
- * {@link IOException}s can happen when we have no data available in the - * buffer; in that case, we fetch more data to know if we can have a next - * sub-stream or not. - *
- * This is can be a blocking call when data need to be fetched. - * - * @return TRUE if we unblocked the next sub-stream, FALSE if not (i.e., - * FALSE when there are no more sub-streams to fetch) - * - * @throws IOException - * in case of I/O error or if the stream is closed - */ - public boolean next() throws IOException { - return next(false); - } - - /** - * Unblock the next sub-stream as would have done - * {@link NextableInputStream#next()}, but disable the sub-stream systems. - *
- * That is, the next stream, if any, will be the last one and will not be - * subject to the {@link NextableInputStreamStep}. - *
- * This is can be a blocking call when data need to be fetched. - * - * @return TRUE if we unblocked the next sub-stream, FALSE if not - * - * @throws IOException - * in case of I/O error or if the stream is closed - */ - public boolean nextAll() throws IOException { - return next(true); - } - - /** - * Check if this stream is totally spent (no more data to read or to - * process). - *
- * Note: when the stream is divided into sub-streams, each sub-stream will - * report its own eof when spent. - * - * @return TRUE if it is - * - * @throws IOException - * in case of I/O error - */ - @Override - public boolean eof() throws IOException { - return super.eof(); - } - - /** - * Check if we still have some data in the buffer and, if not, fetch some. - * - * @return TRUE if we fetched some data, FALSE if there are still some in - * the buffer - * - * @throws IOException - * in case of I/O error - */ - @Override - protected boolean preRead() throws IOException { - if (!stopped) { - boolean bufferChanged = super.preRead(); - checkBuffer(bufferChanged); - return bufferChanged; - } - - if (start >= stop) { - eof = true; - } - - return false; - } - - @Override - protected boolean hasMoreData() { - return started && super.hasMoreData(); - } - - /** - * Check that the buffer didn't overshot to the next item, and fix - * {@link NextableInputStream#stop} if needed. - *
- * If {@link NextableInputStream#stop} is fixed, - * {@link NextableInputStream#eof} and {@link NextableInputStream#stopped} - * are set to TRUE. - * - * @param newBuffer - * we changed the buffer, we need to clear some information in - * the {@link NextableInputStreamStep} - */ - private void checkBuffer(boolean newBuffer) { - if (step != null && stop >= 0) { - if (newBuffer) { - step.clearBuffer(); - } - - int stopAt = step.stop(buffer, start, stop, eof); - if (stopAt >= 0) { - stop = stopAt; - eof = true; - stopped = true; - } - } - } - - /** - * The implementation of {@link NextableInputStream#next()} and - * {@link NextableInputStream#nextAll()}. - *
- * This is can be a blocking call when data need to be fetched. - * - * @param all - * TRUE for {@link NextableInputStream#nextAll()}, FALSE for - * {@link NextableInputStream#next()} - * - * @return TRUE if we unblocked the next sub-stream, FALSE if not (i.e., - * FALSE when there are no more sub-streams to fetch) - * - * @throws IOException - * in case of I/O error or if the stream is closed - */ - private boolean next(boolean all) throws IOException { - checkClose(); - - if (!started) { - // First call before being allowed to read - started = true; - - if (all) { - step = null; - } - - return true; - } - - // If started, must be stopped and no more data to continue - // i.e., sub-stream must be spent - if (!stopped || hasMoreData()) { - return false; - } - - if (step != null) { - stop = step.getResumeLen(); - start += step.getResumeSkip(); - eof = step.getResumeEof(); - stopped = false; - - if (all) { - step = null; - } - - checkBuffer(false); - - return true; - } - - return false; - - // // consider that if EOF, there is no next - // if (start >= stop) { - // // Make sure, block if necessary - // preRead(); - // - // return hasMoreData(); - // } - // - // return true; - } - - /** - * Display a DEBUG {@link String} representation of this object. - *
- * Do not use for release code. - */ - @Override - public String toString() { - String data = ""; - if (stop > 0) { - try { - data = new String(Arrays.copyOfRange(buffer, 0, stop), "UTF-8"); - } catch (UnsupportedEncodingException e) { - } - if (data.length() > 200) { - data = data.substring(0, 197) + "..."; - } - } - String rep = String.format( - "Nextable %s: %d -> %d [eof: %s] [more data: %s]: %s", - (stopped ? "stopped" : "running"), start, stop, "" + eof, "" - + hasMoreData(), data); - - return rep; - } -}