public class CursorFileManager implements CursorManager{public void write(String key, LongCursor cursor) throws IOException

    {

        File file = new File(key);

        if (cursor == null) {

            if (file.exists()) {

                file.delete();

            }

            return;

        }

    FileWriter fileWriter = null;

    try {

        fileWriter = new FileWriter(file);

        JSON.writeJSONStringTo(cursor, fileWriter, new SerializerFeature[0]);

    } catch (Exception e) {

        this.logger.error(e.getMessage(), e);

    } finally {

        if (fileWriter != null)

            fileWriter.close();

    }

  }

public LongCursor read(String key){

    JSONReader reader = null;

    try {

        File file = new File(key);

        this.logger.info("try to read cursor from file={}", file.getAbsolutePath());

        if (!file.exists()) {

            return null;

        }

        reader = new JSONReader(new FileReader(file));

        LongCursor cursor = (LongCursor)reader.readObject(LongCursor.class);

        return cursor;

    } catch (Exception e) {

        this.logger.error(e.getMessage(), e);

    } finally {

        if (reader != null)

          reader.close();

    }

    return null;

}

public LongCursor read() {

    LongCursor cursor = cursorManager.read(cursorPath + "/" + fileName);

    if (cursor != null) {

        String biz = cursor.getBiz();

        if (biz != null && biz.length() > 0) {

            String[] secs = biz.split("-");

            shouldWait = Boolean.parseBoolean(secs[0]);

            if (secs.length > 1) {

                completedOrderId = Long.valueOf(secs[1]);

            }

        }

    }

    return cursor;

}

public void write(LongCursor cursor) throws IOException {

    cursor.setBiz(shouldWait + "-" + completedOrderId);

    cursorManager.write(cursorPath + "/" + fileName, cursor);

}