HelloModel.java

package com.example;
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;

import java.io.File;


/**
 * Model layer: encapsulates application data and business logic.
 */
public class HelloModel {

     private final NtfyConnection connection;

     private final ObservableList<NtfyMessageDto> messages = FXCollections.observableArrayList();
     private final StringProperty messageToSend = new SimpleStringProperty();

     public HelloModel(NtfyConnection connection) {
         this.connection = connection;
         receiveMessage();
     }

    public ObservableList<NtfyMessageDto> getMessages() {
         return messages;
    }

    public String getMessageToSend() {
         return messageToSend.get();
    }

    public StringProperty messageToSendProperty() {
         return messageToSend;
    }

    public void setMessageToSend(String message) {
         messageToSend.set(message);
    }

    /**
     * Returns a greeting based on the current Java and JavaFX versions.
     */
    public String getGreeting() {
        return "Chat Client by Adam";
    }

    public void sendMessage() {
        connection.send(messageToSend.get());

    }

    public void receiveMessage() {
        connection.receive(m-> {
            try {
                Platform.runLater(()->messages.add(m));
            } catch (IllegalStateException e) {
                messages.add(m);
            }

        });
    }

    public void sendFile(File file) {
        connection.sendFile(file);
    }
}