Implementing the factory pattern
A common way of creating objects is using the new
keyword with a constructor. However, if this is done repeatedly in many places in a program, the code used to create the object will need to be modified in each location should this process change. Using a factory method will simplify this process. The factory pattern is used to create different instances of different classes of the same base type.
The factory pattern is used to assist in the creation of objects. Where the use of the new
keyword is not advisable, this technique should be used. This includes situations where context-dependent information is needed to create an instance and where we wish to have more control over the creation process.
In the former case, creating a connection to an external resource such as a database may be dependent on several factors. These can include the availability of the server hosting the database, type of database support required, and potentially legal issues such as...