In this lecture we are going to look at different ways to use and enhance the Button class. For each one we will draw a picture of where the input comes in and how the classes interact.

• Two-way interaction: A class interacts with a main program (lab 3)
  • Button.java contains the class definition of the basic button.

    public class Button {
     
        private boolean myIamPushed;
        private Date myCreationDate;
     
        // constructor
        public Button () {
            myIamPushed = false;
            myCreationDate = new Date();
        }
     
        // accessor methods
        public boolean AmIPushed(){
            return myIamPushed;
        }
     
        public String GetWhenMade() {
            return myCreationDate.toString();
        }
     
        // modifier methods
        public void ClearButton() {
            myIamPushed = false;
        }
     
        public void PushButton() {
            myIamPushed = true;
        }
    }
    

  • ButtonMain, java has the main program that creates and tests a button:

       public class ButtonMain {
    
            /**
             * Constructor
             */ 
        public ButtonMain () {
        }
    
        public static void main(String args[]) {
            Button mybutton = new Button();
            mybutton.PushButton();
            System.out.println("mybutton has pushed state = " + mybutton.GetState());
            mybutton.ClearButton();
            System.out.println("mybutton has pushed state =  " + mybutton.GetState());
            System.out.println("mybutton was created on " + mybutton.GetWhenMade());    }
    }
    

• A Three-way interaction: A menu class takes care of querying the user about whether to push or clear for the main (lab 4)
  • ButtonGUI.java contains a button class that pops up a menu:

    import simpleIO.*;
    
    public class ButtonGUI extends SimpleGUI {
    
        private int myCurrentChoice;
    
        // constructor
        public ButtonGUI() {
            super();            // make sure superclass constructor is called
            createMenu();       // create a menu window
            addChoice("Clear");   // add menu option 0 with prompt "Clear"
            addChoice("Push");    // add menu option 1 with prompt "Push"
            myCurrentChoice = 0;
        }
     
        // accessor method
       public int GetCurrentChoice() {
           return myCurrentChoice;
       }
        
        // modifier method
        public int MakeSelection(String menuName) {
           myCurrentChoice = getChoice(menuName);
           return myCurrentChoice;
        }
    }
    

  • ButtonGUITestTwoMain is a simple test program for the ButtonGUI

    public class ButtonGUITestTwoMain {
        /**
         * Constructor
         */
        public ButtonGUITestTwoMain {
        }
    
        public static void main(String args[]) {
                 // Create a menu for entering selections and test it out.
            ButtonGUI myButtonMenu = new ButtonGUI();
            int myPick = myButtonMenu.MakeSelection("Button A");
            System.out.println("I picked " + myPick);
            myPick = myButtonMenu.MakeSelection("Button B");
            System.out.println("I picked " + myPick);
       }
    
    }
    

  • ButtonGUITestThreeMain.java is a main program to test out the three-way interaction:

    public class ButtonGUITestThreeMain {
    
        /**
         * Constructor.
         */
        public ButtonGUITestThreeMain () {
        }
    
        public static void main(String args[]) {
     
                 // Create a button and use myButtonMenu to push or clear it.
            ButtonGUI myButtonMenu = new ButtonGUI(); 
            Button myButton = new Button();
            myPick = myButtonMenu.MakeSelection("Push or clear myButton:");
            if (myPick == 0)
                myButton.ClearButton();
            else if (myPick == 1)
                myButton.PushButton();
            System.out.println("myButton is pushed? " + myButton.AmIPushed());
        }
    }
    

• Button with an internal GUI (The Vendomatic1000)

  import java.util.*;
  import simpleIO.*;
  
  public class VendingButton extends SimpleGUI {
  
      private boolean myIamPushed; 
      private Date myCreationDate;
      private String myName;       
  
      // constructor
      public VendingButton (String buttonName, String firstChoice, String secondChoice) { 
          super();                // make sure the SimpleGUI constructor is called
          createMenu();           // create a menu window
          myName = new String(buttonName);  // make a new String name for the button
          addChoice(firstChoice);  // add menu option 0 with prompt firstChoice
          addChoice(secondChoice); // add menu option 1 with prompt secondChoice
          myIamPushed = false;     // button is cleared initially
          myCreationDate = new Date(); // button keeps track of when it was made 
      }
  
      // accessor methods
      public boolean AmIPushed(){
          return myIamPushed;
      }
  
      public String GetWhenMade() {
          return myCreationDate.toString();
      }
  
      public String GetButtonName() {
          return myName;
      }
  
      // modifier methods
      public void ClearButton() {
          myIamPushed = false;
      }
  
      public void PushButton() {
          myIamPushed = true;
      }
  
      public boolean WaitForButtonPress() {
          int choice = getChoice(myName);
          if (choice == 0)
              myIamPushed = true;
          else
              myIamPushed = false;
          return myIamPushed;
      }
  }
  

• VendingButtonMain.java test program for the VendingButton class

  public class VendingButtonMain {
   
      /**
       * Constructor.
       */
      public VendingButtonMain () {
      }
   
      public static void main(String args[]) {
          VendingButton selectionButton = new VendingButton("Make a selection",
                                                             "Clear", "Push");
          selectionButton.WaitForButtonPress();
      }
  }