Factory Pattern
The Factory pattern allows client code to delegate creation of a particular kind of object to another class (“factory”).
The type of the returned instance can depend on some data supplied by the client or
can be based on the current context or state of the application.
The factory method does not have to have any parameters passed to it, instead it may just examine the existing state of the application to make the decision
Advantages
decouples the calling class from the target class, which result in less coupled and highly cohesive code.
For example:
JDBC is a good example for this pattern; application code doesn’t need to know what database it will be used with, so it doesn’t know what database-specific driver classes it should use.
Instead, it uses factory methods to get Connections, Statements, and other objects to work with. Which gives you flexibility to change your back-end database without changing your DAO layer in case you are using ANSI SQL features and not coded on DBMS specific feature?
enables the subclasses to provide extended version of an object, because creating an object inside factory is more flexible than creating an object directly in the client.
Since client is working on interface level any time you can enhance the implementation and return from Factory.
it encourages consistency in code since every time object is created using Factory rather than using different constructor at different client side.
easy to debug and troubleshoot because you have a centralized method for object creation and every client is getting object from same place.
Static factory method used in factory design pattern enforces use of Interface than implementation which itself is a good practice.
Since factory method have return type as Interface, it allows you to replace implementation with better performance version in newer release.
static factory method pattern is that they can cache frequently used object and eliminate duplicate object creation.
offers alternative way of creating object.
to hide information related to creation of object.
See Wiring class
DI library
case swithc
Supplier java 8
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