I have a situation where I need to abstract with storage functions, and to have multiple database adapters.
However I'm relying on external vendors who also have multiple database adapters for their libraries.
I'd like to create a single adapter be it MySQL that inherits the functions of the corresponding MySQL adapters from the external vendors. I can dependency inject this adapter into my own libraries and the external libraries that depend upon adapters to function.
Of course PHP doesn't have multiple inheritance, so I did some research and came up on composition.
Would compositing multiple database adapters into a single database adapter be a good practice? Furthermore would this composed object work, if it implemented an interface that extends from the corresponding interfaces of the external vendors?
For example imagine having:
External1\StorageInterface
External1\MySQLAdapter
External2\StorageInterface
External2\MySQLAdapter
Internal\StorageInterface
Internal\MySQLAdapter
Now: Internal\StorageInterface extends External1\StorageInterface, External2\StorageInterface
Then: Internal\MySQLAdapter implements Internal\StorageInterface
Then: Internal\MySQLAdapter compositions External1\MySQLAdapter and External2\MySQLAdapter
On a side note, how should the compositing take place? Via __call or reimplementing the function names, and simply calling the child objects? Which one satisfies the interface constraints?
One more question would be, how does one deal if in the case that different adapters have the same function name creating conflict? Would the adapter pattern work?