/*-------------------------------------------------------------------*
 * NTU Student: Java With Engineering Applications, Spring 1999
 * Assignment # 2 - Java How To Program 2nd edition, Deitel & Deitel
 * Problem 4.31 on page 223
 *
 * Michael Kusmierz
 * Xerox Corporation
 * Rev 1.0	Apr 14, 1999 
 *
 * This code represents a students work in progress 
 * and is not to be used beyond that purpose.
 *-------------------------------------------------------------------*/ 

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
/**
 * This type was created in VisualAge.
 * Learn - is an educational program that generates two random numbers
 * and the user is asked to multiply them. Thier answer is verified.
 * A correct answer by the user results in the MultiplicationQuestion
 * method to be called again, otherwise the user is just prompted to try
 * again. Uses: Status Bar, Text field and Text Area.
 */
public class Learn extends Applet implements ActionListener {
	private Label ivjlblAppletTitle = null;
	private Label ivjlblIPrompt = null;
	private TextField ivjtxtFieldAnswer = null;
	private TextArea ivjtxtArea = null;
	//---instance variables
	private int iRndNum1, iRndNum2;	//Random numbers to be multiplied
	private int iUserInputAns;		//User input
	private int iTestStatus;		//init,pass,fail
	private final int k_PASS = 0;
	private final int k_FAIL = -1;
	private final int k_INIT = 1;
	//---carriage return and line feed constant
 		//String crlf = System.getProperties().getProperty("line.separator");
		//- THE ABOVE WORKS in IBM VisualAge & DOES NOT WORK ON JDK 1.2 APPLETVIEWER
	String crlf = "\n";
	public void actionPerformed( ActionEvent e) {
		try {
			//--- get the users guess
			iUserInputAns = Integer.parseInt(ivjtxtFieldAnswer.getText());
					
			//--- compute answer and verify results.. display to user
			if ( (iRndNum1 * iRndNum2) == iUserInputAns)
				iTestStatus = k_PASS;
			else
				iTestStatus = k_FAIL;

			//--- verify answer in paint
			repaint();
		} catch (Throwable exception) {
			iTestStatus = k_FAIL;
		}
	}
/**
 * Gets the applet information.
 * @return java.lang.String
 */
public String getAppletInfo() {
	return "MultiplicationPkg.Learn created using VisualAge for Java.";
}
/**
 * Return the lblAppletTitle property value.
 * @return java.awt.Label
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Label getlblAppletTitle() {
	if (ivjlblAppletTitle == null) {
		try {
			ivjlblAppletTitle = new java.awt.Label();
			ivjlblAppletTitle.setName("lblAppletTitle");
			ivjlblAppletTitle.setText("Learn Multiplication");
			ivjlblAppletTitle.setBounds(12, 8, 117, 23);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjlblAppletTitle;
}
/**
 * Return the lblIPrompt property value.
 * @return java.awt.Label
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private Label getlblIPrompt() {
	if (ivjlblIPrompt == null) {
		try {
			ivjlblIPrompt = new java.awt.Label();
			ivjlblIPrompt.setName("lblIPrompt");
			ivjlblIPrompt.setText("<enter> Your answer:");
			ivjlblIPrompt.setBounds(9, 31, 135, 24);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjlblIPrompt;
}
/**
 * Return the txtArea property value.
 * @return java.awt.TextArea
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private TextArea gettxtArea() {
	if (ivjtxtArea == null) {
		try {
			ivjtxtArea = new java.awt.TextArea();
			ivjtxtArea.setName("txtArea");
			ivjtxtArea.setBounds(10, 73, 197, 73);
			ivjtxtArea.setEditable(false);
			// user code begin {1}
			
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjtxtArea;
}
/**
 * Return the txtFieldAnswer property value.
 * @return java.awt.TextField
 */
/* WARNING: THIS METHOD WILL BE REGENERATED. */
private TextField gettxtFieldAnswer() {
	if (ivjtxtFieldAnswer == null) {
		try {
			ivjtxtFieldAnswer = new java.awt.TextField();
			ivjtxtFieldAnswer.setName("txtFieldAnswer");
			ivjtxtFieldAnswer.setBounds(147, 30, 58, 24);
			// user code begin {1}
			// user code end
		} catch (java.lang.Throwable ivjExc) {
			// user code begin {2}
			// user code end
			handleException(ivjExc);
		}
	};
	return ivjtxtFieldAnswer;
}
/**
 * Called whenever the part throws an exception.
 * @param exception java.lang.Throwable
 */
private void handleException(Throwable exception) {

	/* Uncomment the following lines to print uncaught exceptions to stdout */
	// System.out.println("--------- UNCAUGHT EXCEPTION ---------");
	// exception.printStackTrace(System.out);
}
/**
 * Handle the Applet init method.
 */
public void init() {
	super.init();
	try {
		setName("Learn");
		setLayout(null);
		setSize(215, 153);
		add(getlblIPrompt(), getlblIPrompt().getName());
		add(gettxtFieldAnswer(), gettxtFieldAnswer().getName());
		add(getlblAppletTitle(), getlblAppletTitle().getName());
		add(gettxtArea(), gettxtArea().getName());
		// user code begin {1}
		
		//--- Initialize instance variables
		iTestStatus = k_INIT;
		
		//--- Wait for an answer from the user
		ivjtxtFieldAnswer.addActionListener(this);
		
		//--- Start the learning game in paint
		//multiplicationQuestion();
				
		// user code end
	} catch (java.lang.Throwable ivjExc) {
		// user code begin {2}
		// user code end
		handleException(ivjExc);
	}
}
/**
 * main entrypoint - starts the part when it is run as an application
 * @param args java.lang.String[]
 */
public static void main(java.lang.String[] args) {
	try {
		Frame frame;
		try {
			Class aFrameClass = Class.forName("com.ibm.uvm.abt.edit.TestFrame");
			frame = (Frame)aFrameClass.newInstance();
		} catch (java.lang.Throwable ivjExc) {
			frame = new Frame();
		}
		Learn aLearn;
		Class iiCls = Class.forName("Learn");
		ClassLoader iiClsLoader = iiCls.getClassLoader();
		aLearn = (Learn)java.beans.Beans.instantiate(iiClsLoader,"Learn");
		frame.add("Center", aLearn);
		frame.setSize(aLearn.getSize());
		frame.setVisible(true);
	} catch (Throwable exception) {
		System.err.println("Exception occurred in main() of java.applet.Applet");
		exception.printStackTrace(System.out);
	}
}
/**
 * Propose a multiplication question...
 */
private void multiplicationQuestion() {
	
	randomNumber();
	showStatus("How much is "+ iRndNum1 + " times " + iRndNum2 + " :");

	//---wait for the user to answer (action listener >>> action performed)
	}
/**
 * Print the results on the applet screen
 */
public void paint(Graphics g) {

	//--- display results to the user

	switch (iTestStatus) {
		case k_INIT:
			ivjtxtArea.setText("...waiting for input."+ crlf);
			multiplicationQuestion();
			//showStatus("How much is "+ iRndNum1 + " times " + iRndNum2 + " :");
			break;
		case k_PASS:
			ivjtxtArea.append(iRndNum1+"x"+iRndNum2+"="+iUserInputAns +" - VERY GOOD!"+ crlf);
			//--- Since the user is so good...give it another try.
			ivjtxtFieldAnswer.setText("");
			multiplicationQuestion();
			break;
		case k_FAIL:
			ivjtxtArea.append(iUserInputAns + " - No, Please try again!"+ crlf);
			//--- Clear the textField
			ivjtxtFieldAnswer.setText("");
			break;
	} //end switch		
}
/**
 * Create two random numbers.
 */
private void randomNumber() {
	//--- Get random numbers between 0 and 9
	iRndNum1 = (int) (Math.random() * 10);	//Math.random returns a double
	iRndNum2 = (int) (Math.random() * 10);	//type cast to integer is ok

}
}