double getLastValue() throws IOException {
try {
// request RRD database reference from the pool
final RrdDb rrdDb = rrdPool.requestRrdDb(rrdFileName);
try {
return rrdDb.getLastDatasourceValue(getDataSourceName());
} finally {
// release RRD database reference
rrdPool.release(rrdDb);
}
} catch (final RrdException e) {
throw createIOException(e);
}
}
