Question

Intro to Java - Assignment

JAVA ASSIGNMENT 13 - Object Methods During Event Handling

Assignment 13

Assignment 13 Preparation

This assignment will focus on the use of object methods during event handling.

Assignment 13

Assignment 13 Submission

Follow the directions below to submit Assignment 13: This assignment will be a modification of the Assignment 12 program (see EncryptionApplication11.java below). Replace the use of String concatenation operations in the methods with StringBuilder or StringBuffer objects and their methods.

EncryptTextMethods.java
======================
package Utils;
import java.util.Scanner;
public class EncryptTextMethods {
public static String encryptString(String message) {
//convert string to character array
char stringChars[] = message.toCharArray();
//for each character
for(int i=0; i< stringChars.length; i++) {
char ch = stringChars[i];
//if character within range of alphabet
if(ch <= 'z' && ch >= 'a') {
stringChars[i] = (char)('a' + ((int)(ch - 'a') + 1) % 26 );
}
}
//construct the string message
return String.valueOf(stringChars);
}
public static String decryptString(String message) {
//convert string to character array
char stringChars[] = message.toCharArray();
//for each character
for(int i=0; i< stringChars.length; i++) {
char ch = stringChars[i];
//if character within range of alphabet
if(ch <= 'z' && ch >= 'a') {
stringChars[i] = (char)('a' + ((int)(ch - 'a') - 1) % 26 );
}
}
//construct the string message
return String.valueOf(stringChars);
}
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Please enter text to encrypt: ");
String message = keyboard.nextLine();
message = message.toLowerCase();
String encryptedStr = encryptString(message);
System.out.println("Encrypted String: " + encryptedStr);
String decryptedStr =decryptString(encryptedStr);
System.out.println("Decrypted String : " + decryptedStr);
keyboard.close();
}
}

EncryptionApplication11.java   (this is Assignment 12)
============================

package Utils;
import javafx.application.*;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.*;
public class EncryptionApplication11 extends Application {
public void start(Stage primaryStage) {
// Create the GridPane pane
GridPane pane = new GridPane();
pane.setPadding(new Insets(10, 10, 10, 10));
pane.setVgap(5);
// Place nodes in the GridPane pane
pane.add(new Label("Input Text:"), 0, 0);
TextArea inputTextArea=new TextArea();
inputTextArea.setPromptText("Input text here");
pane.add(inputTextArea, 0, 1);
// Create FlowPane pane
FlowPane btnPane = new FlowPane();
btnPane.setAlignment(Pos.CENTER);
pane.setHgap(5);
// Place nodes in the FlowPane pane and place
// pane in the GridPane pane
btnPane.setPadding(new Insets(10, 10, 10, 10));
btnPane.setHgap(10);
Button encryptButton = new Button("Encrypt");
Button clearButton = new Button("Clear");
Button decryptButton = new Button("Decrypt");
btnPane.getChildren().addAll(encryptButton, clearButton, decryptButton);
pane.add(btnPane, 0, 2);
// Place nodes in the GridPane pane
pane.add(new Label("Output Text:"), 0, 3);
TextArea outputTextArea=new TextArea("");
outputTextArea.setPromptText("Output text here");
pane.add(outputTextArea, 0, 4);
// Create scene and place it on the stage
Scene scene = new Scene(pane);
primaryStage.setTitle("CPT 236 Encryption Application");
primaryStage.setScene(scene);
primaryStage.show();
// Buttons events
encryptButton.addEventHandler(ActionEvent.ACTION, new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent e) {
String text = inputTextArea.getText();
if(text != null && !text.trim().equals(""))
outputTextArea.setText(EncryptTextMethods.encryptString(text.trim()));
}});
clearButton.addEventHandler(ActionEvent.ACTION, new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent e) {
inputTextArea.clear();
outputTextArea.clear();
}
});
decryptButton.addEventHandler(ActionEvent.ACTION, new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent e) {
String text = inputTextArea.getText();
if(text != null && !text.trim().equals(""))
outputTextArea.setText(EncryptTextMethods.decryptString(text.trim()));
}});
}
/**
* The main method is only needed for the IDE with limited JavaFX support.
* Not needed for running from the command line.
*/
public static void main(String[] args) {
launch(args);
}
}