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IV Patterns are discoverable and documentable
V Patterns are not methods or framework
VI Patterns give you hint to solve a problem effectively
Categorizing Design Patterns:
Patterns focus on different types of problems. Related patterns
are grouped together and assigned a type. This helps
programmers to identify similar types and further it simplifies
the process of comparing similar patterns to find the appropriate
one(s) to utilize.
I Classification of Design Patterns in general spectrum:
1 Creational Patterns
2 Structural Patterns
3 Behavioral Patterns
II JEE-specific Design Patterns
1 Presentation tier patterns
2 Business tier patterns
3 Data Access tier patterns
1. Creational Patterns
This design category is all about the class instantiation.
Creational pattern uses class-creation patterns and objectcreational
patterns. The class-creation pattern uses inheritance
effectively in the instantiation process while objectcreation
pattern uses delegation to get the job done. All the
creational patterns define the best possible way to instantiate
an object. They describes the best way to create the object
instances. Many times, nature of the created object changes
according to the nature of the program. In such scenarios,
we use patterns to give this a more general and flexible
approach, for example a object instance can be created using
a new operator, which is a hard coding methodology (hard |
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coding should be the last option to go with).
There are five types of Creational Patterns.
I Factory Pattern
II Abstract Factory Pattern
III Builder Pattern
IV Prototype Pattern
V Singleton Pattern
2. Structural Patterns
Structural Patterns describe how objects and classes can be
combined to form larger structures. The difference between
class patterns and object patterns is that class patterns
describe abstraction using inheritance and describe how it can
be used to provide more useful program interface. Object
patterns, on other hand, describe how objects can be associated
and composed to form larger, more complex structures.
There are seven structural patterns described. They are as
follows:
I Adapter Pattern
II Bridge Pattern
III Composite Pattern
IV Decorator Pattern
V Facade Pattern
VI Flyweight Pattern
VII Proxy Pattern
3. Behavioral Patterns
Behavioral patterns are those patterns which are specifically
concerned with communication (interaction) between the
objects. The interactions between the objects should be such
that they are talking to each other and still are loosely
coupled. The loose coupling is the key to n-tier architectures.
In this, the implementations and the client should be loosely
coupled in order to avoid hard-coding and dependencies. The behavioral patterns are:
• Chain of Responsibility Pattern
• Command Pattern
• Interpreter Pattern
• Iterator Pattern
• Mediator Pattern
• Momento Pattern
• Observer Pattern
• State Pattern
• Strategy Pattern
• Template Pattern
• Visitor Pattern
II JEE-specific Design patterns:
The term JEE is tossed around a lot because it covers the |
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July 2007 | Java Jazz Up |28 |
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31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53 , Download PDF |
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