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Composition

Java Composition

  1. Consider composition instead of subclassing

    by , 04-26-2012 at 07:16 PM
    Composition might be considered as subclassingís alternative.

    Composition :
    • is simply implemented by all call forwarding to object field.
    • consists of zero dependence upon the object fieldís implementation details.
    • is considerably much more flexible, as it is dynamically defined at the runtime instead of compile time


    Subclassing issues are :

    • Encapsulation is violated since the implementation of subclass & superclass gets tightly
    ...
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    Composition
  2. Composition and Aggregation using Java

    by , 04-26-2012 at 07:15 PM
    Always, there exist a confusion b/w aggregation & composition. In case of a practical field of aggregation and compostion, it shall be kept in minf that both of them are of association type. Below is given the definition of term. After that practical java code is given so that to exactly understand that how aggregation and composition implementation could be implemented in programming.

    Composition:
    Objectís life time is considered to be the same. For instance, composition ...
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    Composition
  3. Choosing composition vs. inheritance

    by , 04-26-2012 at 07:14 PM
    Both inheritance and composition permits you to put the sub-objects in new class. One may be amazed regarding the difference present b/w two and when one could be chooses over the other.

    Generally, composition is used if an existing class features are required in your new class but not the interface. This means that an object is embedded to use it for implementation of functionality of your new class. However, your new class user may see the interface that has been defined instead ...
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    Composition
  4. Composition

    by , 04-26-2012 at 07:13 PM
    In object oriented design when progress is made, various objects will be encountered in problem domain which holds many other objects. In such cases, one will need to model a same kind of arrangement, in your solutionís design. In case of Java programís object oriented design, the manner in which objects are modeled that have other objects, is with composition. Constituent object references become the containing objectís field, with composition.

    For instance it is considered to be ...
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  5. Design Principle: Choose Composition vs. Inheritance

    by , 11-30-2011 at 03:48 AM
    With composition or inheritance you can place sub-objects inside your new class. If you do this explicitly than you are using composition otherwise if you do this implicitly, you are using inheritance. I will outline the difference between the two below as well as point out one of the key design patterns to use in your development. Prefer composition vs inheritance.

    Composition is used when you want the features of an existing class to be included inside your new class, but not be ...
  6. Composition Syntax for Reuse

    by , 11-29-2011 at 06:21 PM
    One of the best features of Java is code reuse. But like any tool, it needs to be used effectively. Most programmers might be lead to think that when I talk of reuse only relates to extending a class. Now there is nothing wrong with reusing a class by extending it or using it directly. This type of reuse is using the class without the risk changing the existing code. First we can create objects of the existing class inside the new class. We call this composition. It is a new class composed of objects ...
  7. Composition Rather than Inheritance

    by , 11-29-2011 at 02:27 AM
    One of the more abused features of object oriented languages is inheritance. Second on the list of abused features of Java as an outgrowth of inheritance is the use of polymorphism. Developers seem to believe that everything should be inherited, and that classes should use polymorphism for every object irrespective of whether the arguments will be provided from external sources. Doing these sorts of things will make your designs more difficult to understand and lead to complications later when ...