CODEWITHSUNDEEP
oopdesign-patterns
Marty Wallace
Marty Wallace

Reputation: 35734

Design pattern - object used for common data access

I am looking for the correct design pattern to use in the following situation:

I have a process which runs and during this process I need to attach several properties to an object in the system. The object is of the same type but at runtime it might exhibit slightly different behaviour and therefore the way the properties are set can be different depending on the type.

Regardless of the type and behaviour of these objects I want to set the same properties on each.

I then need an object to parse these properties at another point in the process

What is the best way to approach this?

Upvotes: 1

Views: 259

Answers (2)

Bob Horn
Bob Horn

Reputation: 34297

I would suggest you not try to pick a design pattern before coding. First, write the code. Then, start abstracting any redundant code, or code that varies. To understand abstracting code that varies, read Head First Design Patterns. At the very beginning of that book is an example of abstracting what varies, using the strategy pattern. The SimUDuck example there is one of the best-explained examples I've ever seen of the strategy pattern. It sounds like that's what you're asking about. However, your question doesn't have a concrete example of what you're trying to do, so giving a concrete example is difficult here.

Having said that, it sounds like you need good, ol' fashioned polymorphism here: you need to treat all objects the same way, and set the same properties, just with different values. To do this, create an interface and have all of your different types implement that interface. Then, in the calling/consuming code, deal with each of those concrete types as the interface.

If you try to pick a design pattern first, many times you'll end up finding that things change based on the details of the implementation, and your original guess at a design pattern ends up being the wrong fit. Then you end up coding to meet a design pattern and not solving the real problem. Write the code first, even if it's ugly. Get it working. Then find areas to abstract and it will naturally evolve into a design pattern on its own.

Upvotes: 1

zzfima
zzfima

Reputation: 1565

If i properly understand, you want add behaviours in runtime??? If yes, so i think - decorator (aka wrapper) design pattern can be good.

Upvotes: 0

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