To change this template file, choose Tools | Templates. * and open the template in the editor. */. package polymorphisme;. import r;. import eric. Ce cours introduit la programmation orientée objet (encapsulation, abstration, héritage, polymorphisme) en l’illustrant en langage Java. Il présuppose connues . Membres · Modificateurs d’accès; Héritage; Encapsulation · Polymorphisme · Classes En Java, ce mécanisme est mis en œuvre au moyen du mot-clé extends.
|Published (Last):||24 April 2004|
|PDF File Size:||5.11 Mb|
|ePub File Size:||2.37 Mb|
|Price:||Free* [*Free Regsitration Required]|
The dictionary definition of polymorphism refers to a principle in biology in which an organism or species can have many different forms or ajva. Multiple Inheritance of State, Implementation, and Type. The type of the reference variable would determine the methods that it can invoke on the object. A reference variable can refer to any object of its declared type or any subtype of its declared type. Polymorphism is the ability of an object to take on many forms. Interfaces polymorphime Inheritance Section: Now, the Deer class is considered to be polymorphic since this has multiple inheritance.
Note the overridden printDescription method. To demonstrate polymorphic features in the Java language, extend the Bicycle class with a MountainBike and a RoadBike class. Java – Polymorphism Jsva. The RoadBike has 23 MM tires.
In addition to the information provided before, additional data about the suspension is included to the output. Here is the RoadBike class:. The reference variable can be reassigned to other objects provided that it is not declared final.
A reference variable can be declared as a class or polymorphismd type. Here is a test program that creates three Bicycle variables.
Note that once again, the printDescription method has been overridden. Bike is in gear 5 with a cadence of 20 and travelling at a speed of To summarize, there are three classes: It is important to know that the only possible way to access an object is polymorphieme a reference variable. Bike is in gear 8 with a cadence of 40 and travelling at a speed of Subclasses of a class can define their own unique behaviors and yet share some of the same functionality of the parent class.
This behavior is referred to as virtual method invocation and demonstrates an aspect of the important polymorphism features in the Java language. For polyomrphisme, a printDescription method could be added to the class that displays all the data currently stored in an instance.
This principle can also be applied to object-oriented programming and languages like the Java language. It does not call the method that is defined by the variable’s type.
Any Java object that can pass more than one IS-A test is considered to be polymorphic. Because road or racing bikes have skinny tires, add an attribute to track the tire width.
One using a Salary reference sand the other using an Employee reference e. An overridden method is invoked at run time, no matter what data type the reference is that was used in the source code at compile time.
Java – Polymorphism
When the compiler sees e. In Java, all Java objects are polymorphic since any object will pass the IS-A test for their own type and for the class Object. The two subclasses override the printDescription method and print unique information.
The MountainBike has a Dual suspension. Each variable is then printed. This time, information about the tire width is displayed. For MountainBikeadd a field for suspensionwhich is a String value that indicates if the bike has a front shock absorber, Front.
Programmation Java/Héritage — Wikilivres
Here, we instantiate two Salary objects. A reference variable can be of only one type. This behavior is referred to as virtual method invocation, and these methods are referred to as virtual methods.