Refactoring a god Manager class

Question

I am running in the exact problem Robert Martin mentioned when having a class named Manager, mine has too much (redudant) code.

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I am writing a system doing computations on many buffers containing data form a timestamped source.

• The Buffers store different data types, they are template classes.
• When a new Observation arrives, a BufferManager distributes and processes fields of the Observation to the different Buffers.
• A common user operation is to access a time interval of a given buffer.

I have a BufferID emum of names in the BufferManager, one for each Buffer and then I have dictionaries (std::map) in the BufferManager, one for each type of Buffer.

The user then gets a desired interval of a Buffer by calling:

Type1Interval int1 =  BufferManager.getType1BufferInterval(BufferID, starTime, endTime)
...
TypeNInterval intN = BufferManager.getTypeNBufferInterval(BufferID, starTime, endTime)

where the only difference between two such functions is that getTypeJBufferInterval accesses the dictionary containing buffers of type J.

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How can I, given a BufferID and a time interval, return the corresponding Buffer(values) without having to have all these different functions?

Answer 1

You can use the single responsibility rule to split apart this manager class.

From your description, the BufferManager holds the collection of buffers, distributes and processes the observations, and provides access to the intervals of the buffers.

The first step is to split the data from the manager. The map and the enum don't belong to the manager. Maybe you want to tie them together, in which case you'd make a separate class that owns the map and enum and say call it BufferMap.

Then you can have 2 different classes (or 3 if distributing and processing are separable). So make an ObservationProcessor, and a BufferIntervalCalculator. Then your 2 methods become:

BufferIntervalCalculator bufferIntervalCalculator(bufferMap);
ObservationProcessor observationProcessor(bufferMap);
observationProcessor.Process(observation);

Type1Interval int1 = bufferIntervalCalculator.calculateInterval<Type1Interval>(BufferId, startTime, endTime);
...
TypeNInterval intN = bufferIntervalCalculator.calculateInterval<TypeNInterval>(BufferId, startTime, endTime);