Setter Methods

Setter methods, also known as mutator methods, merely set the value of a field to a value specified by the argument to the method. These methods almost always return void.

One common idiom in setter methods is to use this.name to refer to the field and give the argument the same name as the field. For example,

class Car {

  String licensePlate; // e.g. "New York A456 324"
  double speed;        // kilometers per hour
  double maxSpeed;     // kilometers per hour
  
  // setter method for the license plate property
  void setLicensePlate(String licensePlate) {
    this.licensePlate = licensePlate;
  }

  // setter method for the maxSpeed property
  void setMaximumSpeed(double maxSpeed) {
    if (maxSpeed > 0) this.maxSpeed = maxSpeed;
    else this.maxSpeed = 0.0;
  }

  // accelerate to maximum speed
  // put the pedal to the metal
  void floorIt() {
    this.speed = this.maxSpeed;  
  }
  
  void accelerate(double deltaV) {

     this.speed = this.speed + deltaV;
     if (this.speed > this.maxSpeed) {
       this.speed = this.maxSpeed; 
     }
     if (this.speed <  0.0) {
       this.speed = 0.0; 
     }     
     
  }
  
}