public int read()

in src/main/java/org/apache/commons/io/input/ReadAheadInputStream.java [319:352]

28 lines of code
6 McCabe index (conditional complexity)


    public int read(final byte[] b, final int offset, int len) throws IOException {
        if (offset < 0 || len < 0 || len > b.length - offset) {
            throw new IndexOutOfBoundsException();
        }
        if (len == 0) {
            return 0;
        }

        if (!activeBuffer.hasRemaining()) {
            // No remaining in active buffer - lock and switch to write ahead buffer.
            stateChangeLock.lock();
            try {
                waitForAsyncReadComplete();
                if (!readAheadBuffer.hasRemaining()) {
                    // The first read.
                    readAsync();
                    waitForAsyncReadComplete();
                    if (isEndOfStream()) {
                        return EOF;
                    }
                }
                // Swap the newly read ahead buffer in place of empty active buffer.
                swapBuffers();
                // After swapping buffers, trigger another async read for read ahead buffer.
                readAsync();
            } finally {
                stateChangeLock.unlock();
            }
        }
        len = Math.min(len, activeBuffer.remaining());
        activeBuffer.get(b, offset, len);

        return len;
    }