Recitation 8

1. Recitation 8 October 15, 2010

2. Today’s Goals: • Overriding versus overloading a method • Implement overloading the equals() on LineSegment class • Implement overriding the equals() on LineSegmentCollection class

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

4. 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

5. 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

6. Overriding & Overloading Object equals()

7. Recitation Specification • Copy classes and interfaces created last week • OverloadLineSegment equals() method: • Return true if the properties of the LineSegment equals that of the object passed in. • Should have a type of LineSegment, not ALineSegment or AVerticalLineSegment • OverrideALineSegmentCollection equals() method: • Check the size of both collections and match each object for all possible indexes. • Add objects of type ALineSegment and AVerticalLineSegment to the collection. • Call equals on LineSegments and LineSegmentCollections that are the same and different. Output the result to the console.

8. Setup and Submission • Please follow the instructions on the course website to set up and submit your projects! • Set up your project: • http://www.cs.unc.edu/~dewan/comp114/f10/Recitations/makeproject/ • Submit an assignment: • http://www.cs.unc.edu/~dewan/comp114/f10/Recitations/submit/ • Ask us if you have *ANY* questions on submission

9. Setting up Object Editor • Recall from lecture: • Jar must be on build path • Import statement necessary! • import bus.uigen.ObjectEditor; • Must call ObjectEditor.edit(yourObject);