Getter and Setter

[tongshen9095]

Getter and Setter - DZone

The class declares a private field, number. Since number is private, the code from the outside of this class cannot access the variable directly.

Instead, the outside code has to invoke the getter, getNumber(), and the setter, setNumber(), in order to read or update the variable.

By using getter and setter, the programmer can control how their important variables are accessed and updated in the proper manner, such as changing the value of a variable within a specified range.

public class SimpleGetterAndSetter {
    private int number;
    // getter
    public int getNumber() {
        return this.number;
    }
    // setter
    public void setNumber(int num) {
        this.number = num;
    }
}

[tongshen9095]

Q: Does every private field need a getter and a setter? A: No.

Q: Difference between the following two methods? A: We can set control number range in setNumber()

// method 1
public int number;

// method 2
private int number;

public void setNumber(int num) {
  this.number = num;
}

Q: Private field, without setter A: Read-only variable. Initialize with the constructor.