Tech Titans_SY_2

MessagingSystem.java

@@ -0,0 +1,212 @@
+package DSL;
+
+import java.util.*;
+import java.util.Queue;
+import java.util.Scanner;
+import java.util.Stack;
+
+class Message {
+	private int msgId;
+	private String sender;
+	private String receiver;
+	private String msg;
+	private String User;
+
+	private int nextMessageId = 1;
+
+	public Message(String sender, String receiver, String msg) {
+		this.msgId = nextMessageId++;
+		this.sender = sender;
+		this.receiver = receiver;
+		this.msg = msg;
+	}
+
+	public int getNextMessageId() {
+
+		return nextMessageId;
+	}
+
+	public void setNextMessageId(int nextMessageId) {
+
+		this.nextMessageId = nextMessageId;
+	}
+
+	public int getMessageId() {
+		msgId = nextMessageId++;
+		return msgId;
+	}
+
+	public String getSender() {
+		return sender;
+	}
+
+	public String getReceiver() {
+		return receiver;
+	}
+
+	public String getMsg() {
+		return msg;
+	}
+
+	public void setMsgId(int msgId) {
+		msgId = nextMessageId++;
+		this.msgId = msgId;
+	}
+}
+
+public class MessagingSystem {
+
+	private Queue<Message> msgQueue;
+	private Stack<Message> msgStack;
+	private Queue<Message> undoMsgQueue;
+
+	public MessagingSystem() {
+		this.msgQueue = new LinkedList<>();
+		this.msgStack = new Stack<>();
+		this.undoMsgQueue = new LinkedList<>();
+	}
+
+	public void sendMessage(Message message) {
+		msgQueue.offer(message);
+		// when a new message is sent, reset the undone message queue
+		undoMsgQueue.clear();
+		Message msg = new Message(null, null, null);
+		System.out.println("Message ID = " + msg.getNextMessageId());
+	}
+
+	public Message receiveMsg() {
+		if (!msgQueue.isEmpty()) {
+			Message message = msgQueue.poll();
+			msgStack.push(message);
+			return message;
+		}
+		return null;
+	}
+
+	public Message undoMsg() { // undo the last msg
+		if (!msgStack.isEmpty()) {
+			Message message = msgStack.pop();
+			undoMsgQueue.offer(message);
+			return message;
+		}
+		return null;
+	}
+
+	public Message redoMsg() { // redo the last message
+		if (!undoMsgQueue.isEmpty()) {
+			Message message = undoMsgQueue.poll();
+			msgStack.push(message);
+			return message;
+		}
+		return null;
+	}
+
+	public void deleteMessage(int messageId) {
+		boolean messageFound = false;
+		Iterator<Message> msgIterator = msgQueue.iterator();
+		while (msgIterator.hasNext()) {
+			Message currentMessage = msgIterator.next();
+			if (currentMessage.getMessageId() == messageId) {
+				msgIterator.remove();
+				messageFound = true;
+				System.out.println("Message with ID " + messageId + " deleted.");
+				break;
+			}
+		}
+		if (!messageFound) {
+			System.out.println("Message with ID " + messageId + " not found.");
+		}
+	}
+
+	// private int getMessageId() {
+	// TODO Auto-generated method stub
+	// return 0;
+	// }
+
+	public Message searchMessage(String keyword) {
+		for (Message message : msgQueue) {
+			if (message.getMsg().contains(keyword)) {
+				return message;
+			}
+		}
+		return null;
+	}
+
+	public static void main(String[] args) {
+		Scanner scanner = new Scanner(System.in);
+		MessagingSystem messagingSystem = new MessagingSystem();
+
+		boolean quit = false;
+		while (!quit) {
+			System.out.println(
+					"Choose an option:\n1. Send a message\n2. Receive a message\n3. Undo last message\n4. Redo last message\n5. Delete a message\n6. Search for a message\n7. Quit");
+			int option = scanner.nextInt();
+			scanner.nextLine(); // consume the newline character
+
+			switch (option) {
+			case 1:
+				System.out.print("Enter sender name: ");
+				String sender = scanner.nextLine();
+				System.out.print("Enter receiver name: ");
+				String receiver = scanner.nextLine();
+				System.out.print("Enter message: ");
+				String msgText = scanner.nextLine();
+
+				messagingSystem.sendMessage(new Message(sender, receiver, msgText));
+				break;
+			case 2:
+				Message receivedMessage = messagingSystem.receiveMsg();
+				if (receivedMessage != null) {
+					// System.out.println("Message ID = "+Message.getMessageId());
+					System.out.println("Message received from " + receivedMessage.getSender() + " to "
+							+ receivedMessage.getReceiver() + ": " + receivedMessage.getMsg());
+				} else {
+					System.out.println("No messages to receive.");
+				}
+				break;
+			case 3:
+				Message undoneMessage = messagingSystem.undoMsg();
+				if (undoneMessage != null) {
+					System.out.println("Last message from " + undoneMessage.getSender() + " to "
+							+ undoneMessage.getReceiver() + " undone.");
+				} else {
+					System.out.println("No messages to undo.");
+				}
+				break;
+			case 4:
+				Message redoMessage = messagingSystem.redoMsg();
+				if (redoMessage != null) {
+					System.out.println("Last message from " + redoMessage.getSender() + " to "
+							+ redoMessage.getReceiver() + " redone.");
+				} else {
+					System.out.println("No messages to redo.");
+				}
+				break;
+			case 5:
+				System.out.print("Enter message ID to delete: ");
+				int messageIdToDelete = scanner.nextInt();
+				scanner.nextLine(); // consume the newline character
+				messagingSystem.deleteMessage(messageIdToDelete);
+				break;
+
+			case 6:
+				System.out.print("Enter keyword to search: ");
+				String keyword = scanner.nextLine();
+				Message foundMessage = messagingSystem.searchMessage(keyword);
+				if (foundMessage != null) {
+					System.out.println("Message found:\n" + foundMessage.getMsg());
+				} else {
+					System.out.println("No message found.");
+				}
+				break;
+			case 7:
+				quit = true;
+				break;
+			default:
+				System.out.println("Invalid option.");
+				break;
+			}
+		}
+		scanner.close();
+	}
+}