NEED HELP THANK YOU Part 1: Defining the Class Write the code to create a class that models a Door object. Dont worry about the internal details just yet. Just give the class a name and an empty body for the moment. We will add more to the class shortly. For example, if we were creating a class to represent a Window, we would use the following: 1 public class Window { // To be filled in later } Part 2: Instance Variables When modeling an object as a class, we also need to describe the properties it possesses. An everyday object that we wish to model always has one or more properties that describe it. For instance a door object might have a name like Front or Side to distinguish it from other doors. Another property that could describe a door is its state: open or closed. Properties of objects are described in code by using nouns like state or name to create instance variables that hold values. Add the following two instance variables to your Door class: a String name to hold the name of the door a String state to hold if the door is opened or closed To protect encapsulation, be sure to make the two instance variables above private variables. For example, if the Window class example above had a name and a variable to hold information about the shades, we could have: public class Window { // instance variables private String name; private String shades; // constructors and methods to be filled in later } Part 3: Constructor Now that we have a Door class, we would like to be able to create some Door objects. Java constructors are components of a class whose purpose is to create objects of the given class and to initialize the objects instance variables. Java provides a constructor with no arguments (the default constructor) for every class and the Door class is no exception. Unfortunately, the default constructor that Java provides initializes the state and name variables to null. This is unacceptable. Add a constructor for the Door class that receives two String arguments: the name of the door and its initial state. Inside the constructor, assign the two instance variables the value of the appropriate argument. Because we want to use the constructor outside of the class, make the access modifier for the constructor public. Remember, the name of the constructor must match the name of the class exactly and the constructor does not have a return type, not even void. For the Window example the following constructor would initialize the name and shades instance variables: public Window (String newName, String newShades) { name = newName; shades = newShades; } 2 Part 4: Accessor Methods It is often convenient to have accessor methods that operate on a single instance variable. Here is an accessor method for the name variable of the Door class: public String getName() { return name; } The word String in front of getName() indicates that the method returns a String when it is invoked. The body is simple and just returns the value of name. Add this method to your class and write a similar accessor method for the state instance variable. Part 5: Mutator Methods Many instance variables in a class will have corresponding mutator methods that allow you to change the value of the variable. Here is a mutator method for the state variable: public void setState(String newState) { state = newState; } The word void in front of setState() indicates that the method does not return a value when it is invoked. The body is simple and copies the value of the parameter variable newState to instance variable state. Add this method to the class and write a similar mutator method for the name instance variable. Part 6: Other Methods Objects also have operations which can be invoked on the object and which may change the object in some way. For instance, the operations for a door object could be open and close. An operation on an object corresponds to a Java method and is described in code by using a verb like open or close. Invoking a method may change the value of an instance variable. For example, invoking close() would change the value of the state variable from open to closed. For example, the open() method could look like: public void open() { state = "open"; } Declare the following two methods in your Door class: a method named open() that takes no arguments, doesnt return a value and sets the value of the instance variable state to open. a method named close() that takes no arguments, doesnt return a value and sets the value of the instance variable state to closed. Because we usually want to allow free access to the methods a class contains, make the access modifier for each method public. Part 7: Testing your Door Class Use the following driver program (also available from the class website under Lab 5) to test your Door class. This file has to be saved as Lab5.java. Make sure you save the file in the same folder as your Door.java file (or in Eclipse create both classes in the same project). Compile and run the code below: 3 /** A class to test the Door class. */ public class Lab5{ /** Tests the methods of the Door class @param args not used */ public static void main(String[] args) { } } // Create a new Door object named ?Front? with initial state ?open? Door frontDoor = new Door("front", "open"); // Print a check that the constructor created the object correctly System.out.println("The " + frontDoor.getName() + " door is " + frontDoor.getState()); System.out.println("Expected: open"); // Create a second Door object with a name ?Back? and state ?closed? Door backDoor = new Door("back", "closed"); // Print a check that the constructor created the object correctly System.out.println("The " + backDoor.getName() + " door is " + backDoor.getState()); System.out.println("Expected: closed"); // Test the open() method to open the backDoor backDoor.open(); System.out.println("The back door is " + backDoor.getState()); System.out.println("Expected: open"); // Use the mutator to change the name variable backDoor.setName("kitchen"); System.out.println("The back door is now called" + backDoor.getName()); System.out.println("Expected: kitchen"); // Complete the class as described in Part 8 of the Assignment Part 8: Instantiating a new Door Object Create a third Door object in your Lab5.java program to represent a sideDoor with the name property side and an initial state of open. Verify that the object was properly created by printing out its name and state and the expected values (as done above for the frontDoor and backDoor). Use the close() method to change the state of the sideDoor to closed. Verify that the method is working by printing out the new value stored in the state and the expected value (as done for backDoor). Sample Output Below is an example of what your output should roughly look like when this lab is completed. All text in bold represents user input. Sample Run 1: The front door is open Expected: open The back door is closed Expected: closed The back door is open Expected: open The back door is called Kitchen Expected: Kitchen The side door is open 4 Expected: open The side door is closed Expected: closed Submission Submit your Lab5.java and Door.java to the Submission Server. Go to the Submission Server site located on the course website, login, then click on Lab Submissions in the left frame. Choose Lab5 from the drop- down box, click on the browse button and find where you saved your Lab5.java and Door.java on your computer. Upload the file to the site and then click on the Submit button. Your file will be submitted and a screen will show up displaying if your program compiled and what your output is when run on some sample input. You should then check to make sure that the actual file submitted properly and is readable to the grader. To do so click on Grades in the frame on the left of the page and then click on the 0 underneath Lab5. You will again see that your program compiled and the sample output, but you should scroll down to the bottom of the screen and make sure your file is readable as well. Important Note: You may resubmit as many times as you like until the deadline, but we will only mark your last submission.

driver:

/** /** A class to test the Door class. */ public class Lab5 { /** Tests the methods of the Door class @param args not used */ public static void main(String[] args) { // Create a Door object, frontDoor which is initially open Door frontDoor = new Door("Front", "open"); System.out.println("The front door is " + frontDoor.getState()); System.out.println("Expected: open"); // Create a second Door object, backDoor which is initially closed Door backDoor = new Door("Back", "closed"); System.out.println("The back door is " + backDoor.getState()); System.out.println("Expected: closed"); // Use the mutator to change the state variable of the backDoor object backDoor.setState("open"); System.out.println("The back door is " + backDoor.getState()); System.out.println("Expected: open"); // Use the mutator to change the name variable of the backDoor object backDoor.setName("Kitchen"); System.out.println("The back door is called " + backDoor.getName()); System.out.println("Expected: Kitchen"); // Complete the class as described in Part 8 of the Assignment } }