Creation Pattern

These design patterns provides way to create objects while hiding the creation logic, rather than instantiating objects directly using new operator. This gives program more flexibility in deciding which objects need to be created for a given use case.

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    Prototype Design Pattern

    Prototype pattern refers to creating duplicate object while keeping performance in mind. This type of design pattern comes under creational pattern as this pattern provides one of the best way to create an object. Intent Specify the kinds of objects to create using a prototypical instance, and create new objects by copying this prototype. Co-opt one instance of a class for use as a breeder of all future instances. The new operator considered harmful. Problem Application “hard wires” the class of object to create in each “new” expression. Rules of thumb Sometimes creational patterns are competitors: there are cases when either Prototype or Abstract Factory could be used properly. At…

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    Builder Design Pattern

    Builder pattern builds a complex object using simple objects and using a step by step approach. This type of design pattern comes under creational pattern as this pattern provides one of the best ways to create an object. The best way to describe is like building a house, as like while creating a house we can not create house directly hand its more like step by step process to build a house similarly in Builder Design Pattern creation of object is a step by step process. Intent Separate the construction of a complex object from its representation so that the same construction process can create different representations. Parse a complex representation,…

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    Abstract Factory Design Pattern

    Factory of factories. The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes. To keep things simple you can understand it like, you have a set of ‘related’ factory method design pattern. Then you will put all those set of simple factories inside a factory pattern. So in turn you need not be aware of the final concrete class that will be instantiated. You can program for the interface using the top factory. There is also a view that abstract factory is ‘also’ implemented using prototype instead of factory methords pattern. Beginners for now please don’t…

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    Singleton Design Pattern Continued

    Describe Singleton: A singleton class should only have to have single instance in the application. Following is the seudo-code for implementation of singleton class: Implement the cloneable interface and throw CloneNotSupportException so that cloning can not be done for you singleton class. Create private static variable of a class Create private constructor that can not be called from outside; Create a public method which will return the instance of class created at step 2. First Step: Throw exception on cloning of singleton; public class Singleton implements Cloneable{ /** *  Throw Exception on cloning of this exception */ protected Object clone() throws CloneNotSupportedException {      throw new CloneNotSupportedException("A Singleton Class…

  • Creation Pattern,  Design Pattern

    Singleton Design Pattern

    The singleton pattern is a design pattern that restricts the instantiation of a class to one object. This is useful when exactly one object is needed to coordinate actions across the system. The concept is sometimes generalized to systems that operate more efficiently when only one object exists, or that restrict the instantiation to a certain number of objects. The term comes from the mathematical concept of a singleton. Intent of Singleton Ensure a class has only one instance, and provide a global point of access to it. Encapsulated “just-in-time initialization” or “initialization on first use”. Implementation Define a private static attribute in the “single instance” class. Define a public…

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    Factory Design Pattern

    The Factory Design Pattern is probably the most used design pattern in modern programming languages like Java and C#. It comes in different variants and implementations. If you are searching for it, most likely, you’ll find references about the GoF patterns: Factory Method and Abstract Factory. Intent Creates objects without exposing the instantiation logic to the client. Refers to the newly created object through a common interface Applicability & Examples Probably the factory pattern is one of the most used patterns, For example a graphical application works with shapes. In our implementation the drawing framework is the client and the shapes are the products. All the shapes are derived from…

  • Creation Pattern,  Design patterns,  Java Design Patterns

    Builder Design Patterns

    The intent of the Builder design pattern is to separate the construction of a complex object from its representation. By doing so, the same construction process can create different representations.                                                                                                             source from: wikipedia.org Objects creation increased with complexity of an application. Complex objects are made of parts produced by other objects that need special care when being built. An application might need a mechanism for building complex objects that is independent from the ones that make…

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  • Creation Pattern,  Design patterns,  Java Design Patterns

    Prototype Design Patterns or Copy Design Pattern

    Prototype Design Patterns or Copy Design Pattern, Today’s programming is all about effective usage of resources and lower costs to application. Saving is a big issue when it comes to using computer resources, Copy of object is the best instead of creating a new one in case cost to object creation is huge then copy, in design patter you have to copy from couple of best solutions, as here we have two options to get the class object: Create a new Object Copy the Object. Where to use ProtoType Pattern: When creating an object is time consuming and a costly and you already have a most similar object instance in hand,…

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  • Creation Pattern,  Design patterns,  Java Design Patterns

    Creational Patterns

    Creational Design Patterns are one of the classification of Design Patterns which used to deals with object creation of class. Object creation is result in design problems or added complexity to the design. Creational design patterns is solving this problem of object creation by controlling this object creation. Creational design patterns are composed of two concept: One is encapsulating knowledge about which concrete classes the system use.  Another is hiding how instances of these concrete classes are created and combined. Creational design patterns are further catagorized into two design patterns: Object Creational Patterns, which deals with object creation. Class Creational Patterns, which deals with class Instantiation. Object-creational patterns defer part of…

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  • Creation Pattern,  Design patterns,  Java Design Patterns

    What is Factory Design Patterns?

    Creational Patterns      -Factory Pattern Factory of classes. In simple words, if we have a super class and nth sub-classes, and based on data provided, we have to return the object of one of the sub-classes, we use a factory pattern. Let’s take an example to understand this pattern. Let’s suppose an application asks for entering the name and sex of a person. If the sex is Male (M), it displays welcome message saying Hello Mr. <Name> and if the sex is Female (F), it displays message  Welcome to application,  Ms <Name>. The skeleton of the code can be given here. public class Person { // name stringpublic String name;//…

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