Yet Anothe one

2019-12-24T22:28:00.007+05:30

Why study Patterns?

Reuse tried, proven solutions
No need to reinvent the wheel
Provides a head start (we can “Singleton” here)
Provide a higher level prospective (more general and abstract)
Frees us from dealing with the details too early

What does a pattern solve?

Structural problems like:
Abstraction, Encapsulation, Separation of concerns, Coupling and cohesion
Non-functional problems like:
Changeability, Interoperability, Efficiency, Reliability, Testability, and Reusability

Types of patterns

Creational : Address problems of creating an object in a flexible way. Separate creation, from operation/use.
Structural : Address problems of using O-O constructs like inheritance to organize classes and objects into larger structures while keeping these structures flexible.
Behavioral : Address problems of assigning responsibilities to classes.

What does a Pattern look like?

Name: meaningful text that reflects the problem, e.g. Bridge, Mediator, Flyweight
Problem addressed: intent of the pattern, objectives achieved within certain constraints
Context: circumstances under which it can occur, used to determine applicability

Facade
Problem : How can we access a large number of classes with a complex internal interaction in a simple but safe way?
Solution: Introduce a dedicated and simplified interface to a framework or a complex set of classes.

Decorator
Problem: How to add additional responsibilites to an object dynamically?
Solution: Attach additional responsibilities to an object dynamically. Also known as Wrapper.

Chain of Responsibility
Problem: Define a chain of receiver objects having the responsibility, depending on run-time conditions, to either handle a request or forward it to the next receiver on the chain (if any).
Solution: Introduce a series of stand-alone handlers where each handler checks whether it should service the request or forward it to other handler.

Observer
Problem: Define a one-to-many dependency among objects so that when one object changes state, all of its dependents are notified and updated automatically.
Solution: The Observer pattern suggests that you add a subscription mechanism to the publisher class so individual objects can subscribe to or unsubscribe from a stream of events coming from that publisher.

Another test

2019-12-24T22:09:00.001+05:30

Hello World

2019-12-22T13:49:00.002+05:30

First post from JExplorer....