Recitation 8

1. Recitation 8 October 14, 2011

2. Today’s Goals: • Overriding versus overloading a method

3. Notes • Show off your work! • Record what you have done using screen video capture software • Upload to YouTube • Send a link to comp401-help • Doesn’t replace screenshots • Not Graded

4. Extending the Object class • All classes extend the Object class either directly or indirectly

5. Overloading • overloaded methods: • appear in the same class or a subclass • have the same name but, • have different parameter lists, and, • can have different return types [Java Quick Reference]

6. Overloading Object equals() public booleanequals(Example otherExample) { if (otherExample != null) { return (this.getX() == otherExample.getX() && this.getY() == otherExample.getY()); } else return false; } equals defined in Example & Object

7. Overriding • Overridden methods: • appear in subclasses • have the same name as a superclass method • have the same parameter list as a superclass method • have the same return type as a superclass method • A few other conditions you’ll learn later. [Java Quick Reference]

8. Overriding Object equals() public boolean equals(Object obj) { if(objinstanceof Example && obj != null) { Example otherObj = (Example)obj; return (this.getX() == otherObj.getX() && this.getY() == otherObj.getY()); } else return false; } equals defined in Example

9. Overriding & Overloading Object equals()

10. Recitation Specification • Add equals(…) to CartesianLine which overloads Object.equals() • Add equals(…) to CartesianTriangle which overrides Object.equals() • Bonus (for candy): Make equals work in a graphical sense.