Behavioral Design Patterns: State Design Pattern

The State Design Pattern is used when an application has different states, transitions between states and Objects behavior changes according to the changed state. Each Object has its own state defined internally.

Behavioral Design Patterns: Template Method Design Pattern

Sometimes we want to specify the order (algorithm) of operations that a method uses, but allow subclasses to provide their own implementations by using the same order (algorithm) of operations. The intension of this pattern is to define an algorithm of operations in a method, and implementation of those operations is defined in subclasses.

Behavioral Design Patterns: Observer Design Pattern

The second pattern of Behavioral Design Patterns group is Observer Design Pattern. The pattern contains central point (Subject) to which information gathering Objects (Observers) get subscribed to get information on state change in central Point (Subject). Simply we can say that this like subscribed information distribution.

Behavioral Design Patterns : Command Design Pattern

Behavioral Design Patterns are specifically concerned with communication between the objects. The loose coupling is maintained between the communicating objects. In these patterns responsibilities are assigned between the objects through either inheritance or composition.  I have started looking into first pattern of the group, i.e Command Pattern.

Structural Design Patterns : Composite Design Pattern

The Composite Pattern is considerable pattern of Structural Design Patterns group. Composite pattern is solution for building complex systems which are made up of lots of smaller components.  To understand the concept of Composite Pattern we need to understand the terms;
1) Components and
2) Composites

Structural Pattern: Adapter Design Pattern

This is another pattern which lies in structural Design Pattern section. To understand the pattern, let’s assume that there are two persons, one person can understand English language only and another can understand Spanish language only. But the both persons need discuss about an application. Here both persons have different interfaces of language they can understand i.e incompatible interfaces, but the requirement is that they need to discuss on an application issue. There is a solution, that is the any one of two person need to learn others language, but it takes long time to learn a new language, so we don’t want go with that solution. The problem can be solved by adapting a third person who can understand both English and Spanish languages, so that he can act as a translator between two peoples.

Structural Design pattern: Decorator Design Pattern

I have started with Structural Design pattern; at first place I saw the name Decorator Pattern. As I read the name, I thought name itself describing the pattern, and I was right. The Structural Design Patterns uses classes and object to build complex structures. In this post I am going to share the first member of the Structural Design Patterns group, which is Decorator Design Pattern.

Abstract Factory Method: Flex Application using Abstract Factory Method Pattern

I am much exited to learn the design patterns. I have posted the simple Factory and Abstract Factory patterns in previous posts. The real world example gives the real usage of the design patterns. So I started here with a ‘Ice-Cream Shop” Application. The shop contains different king of ice creams. In this application client can submit an order for ice cream and application uses the Abstract Factory pattern to create the ice cream order objects.

Abstract Factory Pattern

This Pattern Defines and interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.
This pattern allows us to encapsulate instantiations of concrete types. The Abstract ‘creator’ defines an interface with a method for creating objects. This method is known as ‘Factory Method.

Simple Factory Design Pattern

The Factory Design pattern is used to create a loose coupling between the Client object and the Product objects by delegating the object creation to a method called a factory; hence the name Factory Method.