public void run()

in src/main/java/org/apache/commons/io/input/Tailer.java [944:1031]
70 lines of code
19 McCabe index (conditional complexity)

    public void run() {
        RandomAccessResourceBridge reader = null;
        try {
            FileTime last = FileTimes.EPOCH; // The last time the file was checked for changes
            long position = 0; // position within the file
            // Open the file
            while (getRun() && reader == null) {
                try {
                    reader = tailable.getRandomAccess(RAF_READ_ONLY_MODE);
                } catch (final FileNotFoundException e) {
                    listener.fileNotFound();
                }
                if (reader == null) {
                    ThreadUtils.sleep(delayDuration);
                } else {
                    // The current position in the file
                    position = tailAtEnd ? tailable.size() : 0;
                    last = tailable.lastModifiedFileTime();
                    reader.seek(position);
                }
            }
            while (getRun()) {
                final boolean newer = tailable.isNewer(last); // IO-279, must be done first
                // Check the file length to see if it was rotated
                final long length = tailable.size();
                if (length < position) {
                    // File was rotated
                    listener.fileRotated();
                    // Reopen the reader after rotation ensuring that the old file is closed iff we re-open it
                    // successfully
                    try (RandomAccessResourceBridge save = reader) {
                        reader = tailable.getRandomAccess(RAF_READ_ONLY_MODE);
                        // At this point, we're sure that the old file is rotated
                        // Finish scanning the old file and then we'll start with the new one
                        try {
                            readLines(save);
                        } catch (final IOException ioe) {
                            listener.handle(ioe);
                        }
                        position = 0;
                    } catch (final FileNotFoundException e) {
                        // in this case we continue to use the previous reader and position values
                        listener.fileNotFound();
                        ThreadUtils.sleep(delayDuration);
                    }
                    continue;
                }
                // File was not rotated
                // See if the file needs to be read again
                if (length > position) {
                    // The file has more content than it did last time
                    position = readLines(reader);
                    last = tailable.lastModifiedFileTime();
                } else if (newer) {
                    /*
                     * This can happen if the file is truncated or overwritten with the exact same length of information. In cases like
                     * this, the file position needs to be reset
                     */
                    position = 0;
                    reader.seek(position); // cannot be null here

                    // Now we can read new lines
                    position = readLines(reader);
                    last = tailable.lastModifiedFileTime();
                }
                if (reOpen && reader != null) {
                    reader.close();
                }
                ThreadUtils.sleep(delayDuration);
                if (getRun() && reOpen) {
                    reader = tailable.getRandomAccess(RAF_READ_ONLY_MODE);
                    reader.seek(position);
                }
            }
        } catch (final InterruptedException e) {
            Thread.currentThread().interrupt();
            listener.handle(e);
        } catch (final Exception e) {
            listener.handle(e);
        } finally {
            try {
                IOUtils.close(reader);
            } catch (final IOException e) {
                listener.handle(e);
            }
            close();
        }
    }