Question

USING BLUEJ:

You will write from scratch a class called Heater that represents an adjustable thermostat. Follow the detailed steps below. This is based on Exercises 2.93 - 2.94 (6e) / 2.92 - 2.93 (5e) in the book, but with slight modifications, so be sure to follow the instructions below.

1. Create a new BlueJ project named LastName-heater using your last name.
2. Create a class named Heater
   • At the top of the source code for Heater, add documentation like this:
     /**
     * Heater project
     * Simulate the behavior of a heater (thermostat)
     *
     * Modifications:
     * List the modifications as you make them
     *
     * @author Your Name
     * @version The Date
     */
3. Add the following 4 int fields:
   • temperature
   • minimum
   • maximum
   • increment
4. Write getters (accessors) and setters (mutators) for each field using standard naming conventions, e.g., getTemperature and setTemperature for the temperature field. You should add a total of 8 methods from this step.
   • Whenever you add a new method, include a documentation block that describes what the method does. For example:
     /**
     * @return current temperature of the heater
     */
   • Modify the setIncrement method so that it does not allow a negative value for the increment. Print an error message if the value given is negative and leave the increment unchanged.
5. Define two constructors for the class:
   • The first constructor takes no parameters. In this constructor, initialize minimum to 0, maximum to 100, increment to 1, and temperature to 50.
   • The second constructor takes 4 parameters and uses them to initialize the fields temperature, minimum, maximum, and increment.
   • Be sure to add a javadoc documentation block for each constructor.
6. Define a method named warmer. This method takes no parameters and raises the temperature by the value of the increment field. However, it should not allow the temperature to go above maximum. If the temperature would go above maximum, print an error message and do not raise the temperature. For example:
   • If temperature=50, increment=3, and maximum=100, after a call to the warmer method, temperature will be 53.
   • If temperature=98, increment=3, and maximum=100, after a call to the warmer method, temperature is still 98 and an error message is printed.
7. Define a method named cooler. This method takes no parameters and lowers the temperature by the value of the increment field. However, it should not allow the temperature to go below minimum. If the temperature would go below minimum, print an error message and do not lower the temperature.
8. Adhere to Java style guidelines as described in Appendix J.
9. Test your code thoroughly! (Don't wait until this step - you should be testing each piece as you go.)
10. Create a jar file of your project.
    1. From BlueJ, choose Project->Create Jar File...
    2. Check the "Include source" check box
    3. Name the file LastName-heater

Answer 1

Here is the code for the following question :

Code :

/*
heater class
*/
class Heater
{
//instance variable
private int temperature;
private int minimum;
private int maximum;
private int increment;
  
/*
@constructor default to initialize instance variable
*/
public Heater()
{
this.temperature = 50;
this.minimum = 0;
this.maximum = 100;
this.increment = 1;
}
  
/*
@constructor parameterized to set all instance variables
*/
public Heater(int temperature, int minimum, int maximum, int increment)
{
this.temperature = temperature;
this.minimum = minimum;
this.maximum = maximum;
this.increment = increment;
}
  
/*
@setter method for all instance variables
*/
public void setTemprature(int temperature)
{
if(temperature > 100)
{
System.out.println("Erro! Can not set temperature above 100");
}
else
{
this.temperature = temperature;
}
}
  
public void setMin(int minimum)
{
this.minimum = minimum;
}
  
public void setMax(int maximum)
{
this.maximum = maximum;
}
  
public void setIncrement(int increment)
{
if( increment < 0)
{
System.out.println("Error! increment can not be a negative value");
}
else{
  
this.increment = increment;
}
}
  
  
/*
@getter method for all instance variables
*/
public int getTemprature()
{
return temperature;
}
  
public int getMinimum()
{
return minimum;
}
  
public int getMaximum()
{
return maximum;
}
  
public int getIncreamnet()
{
return increment;
}
  
/*
@method warmer method to increment the temperature
*/
public void warmer()
{
//check if inresing temp exceed maximum value
if(this.temperature + this.increment <= 100)
{
this.temperature += this.increment;
}
else
{
System.out.println("Error! Can not increase temperature above maximum value");
}
}
  
/*
@method cooler to deecrese the temperature
*/
public void cooler()
{
//check if decreament voilate minimum temperature value
if(this.temperature - this.increment < minimum)
{
System.out.println("Error! temperature can not be lower than minimum value");
}
else
{
this.temperature -= this.increment;
}
}
  
/*
@toString() method
*/
public String toString()
{
String str = "Temp : "+getTemprature() + "\nMin : "+getMinimum() + "\nMax :"
+ getMaximum() + "\nIncreament : "+ getIncreamnet();
return str;
}
}
public class Main
{
   public static void main(String[] args) {
     
   /*
   @object of Heater class
   */
     
   Heater heater1 = new Heater();
     
   //print the object 1
   System.out.println("Object 1 :\n" + heater1.toString());
     
   Heater heater2 = new Heater(10, 0, 100, 4);
     
   //print the object 2
   System.out.println("\nObject 2 :\n"+heater2.toString());
     
   //set the object heater1
   heater1.setTemprature(96);
   heater1.setIncrement(4);
   heater1.setMax(100);
   heater1.setMin(0);
     
   //warmer 96 + 4 = 100
     
   heater1.warmer();
     
   System.out.println("\nTemprature 1: "+ heater1.getTemprature());
     
   //when we call again it will throw Error beacuse 100 + 4 = 104 greater than maximum
   heater1.warmer();
     
   //here Temprature will not increase beacuse of Error
   System.out.println("Temprature 1: "+ heater1.getTemprature() );
     
     
     
   //lets call cooler on heater2
   heater2.cooler(); //10 - 4 = 6
   System.out.println("Temprature 2: "+ heater2.getTemprature());
     

heater2.cooler(); //6 - 4 = 2     
System.out.println("Temprature 2: "+ heater2.getTemprature());
     

heater2.cooler(); //2 - 4 = -2 less than minimum, will throw Error
   System.out.println("Temprature 2: "+ heater2.getTemprature());
     
   }
}

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Output :