OOP Design Pattern / reading information from file or API?

I have (x2) ways to get information for my object:

1. Read from a file stored on the disc
2. Access the application that made the file through the application's API

Once the information is acquired, I'll have methods to:

• Display
• Analyze
• Change the information (again as either a file or through the API)

If I change the information, it need not be the same way that I received the information. Therefore I could:

• Receive the info by file and push the info back by API
• and all the other obvious combinations...

I won't have additional ways to get the data in/out (e.g. API and file cover all options).

The code will be in Matlab, so I don't have easy access to enumerated types and a few other nice programming features, so I'm tempted to use a design pattern rather than a switch inside the class.

Questions

What are appropriate design patterns for this problem?

Should I use a design pattern and write a few classes to get this done or just write a single class with a switch for file or API?