The adapter design pattern

In many cases, we have to make applications work by combining different components together. However, quite often, we have a problem where the component interfaces are incompatible with each other. Similarly with using public or any libraries, which we cannot modify ourselves—it is quite rare that someone else's views will be exactly the same as ours in our current settings. This is where adapters help. Their purpose is to help incompatible interfaces work together without modifying their source code.

We will be showing how adapters work using a class diagram and an example in the next few subsections.

Class diagram

For the adapter class diagram, let's imagine that we want to switch to using a new logging library in our application. The library we are trying to use has a log method that takes the message and the severity of the log. However, throughout our whole application, we expect to have the info, debug, warning and error methods that only take the message and...