Trouble understanding Object State, Behavior, and Identity?

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面向向阳花
面向向阳花 2021-01-30 11:42

I have been instructed by my professor to introduce myself on a page as if I were an object, and that I must address three things:
1) Object State, 2) Behavior, and 3) Ident

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  •  滥情空心
    2021-01-30 12:03

    Characteristics of objects are:

    State: what the objects have, Student have a first name, last name, age, etc

    Behavior: what the objects do, Student attend a course "Java for beginners"

    Identity: what makes them unique, Student have Student-ID-number, or an email which is unique. (this is important when implementing the equals method, to determine if the objects are different or not)

    Student john = new Student("John");
    john.setCurrentActivity("Learning Java");
    john.setAge(21);
    john.setWeight(173);
    john.setAddress(...);
    john.setHobbies(...);
    

    and you can figure out the getters.

    public class Student {
        private String name;
        private int    age;
        //etc
    
        // construct a new student 
        public Student(String name) {
            this.name   = name;
        }
    
        public setAge(int age) {
            this.age   = age;
        }
    
        public int getAge() {
            return age;
        }
    }
    

    An illustration of a Car object, which I found that might help you some...

    Car state:

    • Speed
    • RPM
    • Gear
    • Direction
    • Fuel level
    • Engine temperature

    Behaviors:

    • Change Gear
    • Go faster/slower
    • Go in reverse
    • Stop
    • Shut-off

    Identity:

    • VIN
    • License Plate

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