GUI

//Submitted by Dima Yankovoy 311868442 & Snir Yacoby 201561933

package il.ac.hit.project.view;
import il.ac.hit.project.model.*;
import javax.swing.*;
import org.apache.log4j.Logger;
import java.awt.event.*;
import java.awt.*;

/**
 * This class is responsible for the creation of the main user interface window,
 */
public class GUI {

    //main window frame which will display the GUI of the project
    private JFrame mainFrame = null;
    ////
    /**
     * reader - represents the main model part of the application - responsible for data importing from online file,
     * and storing the data in a local file.
     * importCycle - a thread object which receives the reader as the runnable parameter - initiates the continuous
     * up-to-date checkup of the data.
     * currList - array of strings that stores the currency codes that are displayed as a choice - in the "from"
     * and "to" fields.
     * currencyTable - a reference to ana object of class TableBuilder - that is responsible of constructing the
     * JTable with information that comes from the model part of the project.
     */
    private XMLReader reader = null;
    private Thread importCycle = null;
    private String[] currList = null;
    private TableBuilder currencyTable = null;

    //swing components initialization
    private JComboBox<String> fromList = null;
    private JComboBox<String> toList = null;
    private JTextField sumField = null;
    private JTextField resultField = null;
    private JButton convertBtn = null;
    private JButton callTable = null;
    //logger for the gui
    private Logger guiLogger = Logger.getLogger("GUI");

    /**
     * Builds the main user interface.
     */
    public GUI(){

        //Initialize the XMLReader reference as Currencies - the model's class written in scala
        reader = new Currencies();
        //Creation of separate thread for the model - does the continuous checking of online XML file, when started
        importCycle = new Thread(reader,"Import-Cycle");
        //start of the thread responsible for checking of the online document
        boolean status = true;
        importCycle.start();
        //The following sleep() method activation allows the importCycle thread to finish it's function before
        //the GUI is shown on screen
        try
        {
         Thread.sleep(2000);
        }
        catch(InterruptedException e){
            e.printStackTrace();
        }

        //status that is displayed within the lblStatus on the GUI.
        status = reader.getStatus();
        JLabel lblStatus = new JLabel(status ? ("Online") : ("Offline"));
        lblStatus.setForeground(status ? (Color.green) : (Color.red));
        JLabel lblLastUpdate = new JLabel("Last Update was on: "+reader.getLastUpdate());

        //creation of the TableBuilder object with the data received from the model part.
        currencyTable = new TableBuilder(reader.getData());

        //Components Initialization
        JLabel headerText = new JLabel("Currency Rate Converter");
        JLabel lblFrom = new JLabel("From:");
        JLabel lblSum = new JLabel("Sum to calculate:");
        JLabel lblTo = new JLabel("To:");
        JLabel lblResult = new JLabel("Result: ");
        convertBtn = new JButton("Convert Sum");
        callTable = new JButton("Currencies Table");
        sumField = new JTextField(4);
        resultField = new JTextField(16);
        resultField.setEditable(false);

        //Use getColumn method of TableBuilder class to initialize currList - names of Currencies
        //for fromList and toList
        currList = (String[])currencyTable.getColumn(1);
        fromList = new JComboBox<String>(currList);
        toList = new JComboBox<String>(currList);

        //Button Listeners addition - convert & callTable buttons
        ActionListener convertListener = new BtnListener();
        convertBtn.addActionListener(convertListener);
        ActionListener callTableListener = new BtnListener();
        callTable.addActionListener(callTableListener);

        //Sub-Containers - each panel stores other components, while some used for spacing
        //each panel named with a number which indicates the order of appearance in the window
        JPanel panelHeader1 = new JPanel();
        JPanel panelSums2 = new JPanel();
        JPanel panelConvert3 = new JPanel();
        JPanel panelSpc4 = new JPanel();
        JPanel panelResult5 = new JPanel();
        JPanel panelSpc6 = new JPanel();
        JPanel panelTable7 = new JPanel();
        JPanel panelSpc8 = new JPanel();
        JPanel panelStatus9 = new JPanel();
        /////////////////////////////
        //Sub-Containers initialization with the proper components
        panelHeader1.add(headerText);
        panelSums2.add(lblSum);
        panelSums2.add(sumField);
        panelSums2.add(lblFrom);
        panelSums2.add(fromList);
        panelSums2.add(lblTo);
        panelSums2.add(toList);
        panelConvert3.add(convertBtn);
        panelResult5.add(lblResult);
        panelResult5.add(resultField);
        panelTable7.add(callTable);
        panelStatus9.add(lblStatus);
        panelStatus9.add(lblLastUpdate);

        //Adding the Sub-Containers to the main Window Frame
        mainFrame = new JFrame("Currency Rate Converter");
        mainFrame.setLayout(new GridLayout(10,1));
        mainFrame.add(panelHeader1);
        mainFrame.add(panelSums2);
        mainFrame.add(panelConvert3);
        mainFrame.add(panelSpc4);
        mainFrame.add(panelResult5);
        mainFrame.add(panelSpc6);
        mainFrame.add(panelTable7);
        mainFrame.add(panelSpc8);
        mainFrame.add(panelStatus9);

        mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    /**
     * Used for activating the main window of the Currency Converter:
     * setting the size and visibility and starting the thread which is responsible
     * for the import and update of the local currencies file.
     */
    public void go(){
        mainFrame.setSize(500, 400);
        mainFrame.setVisible(true);
    }

    /**
     * Inner class BtnListener is used for assigning actions to take when a click on
     * a specific button occurs.
     * There are two scenarios : 1)pressing the CallTable JButton shows the table's window frame on screen.
     * 2)pressing the convert Button calls for the convert method within the model, and does the
     * required calculations.
     */
    class BtnListener implements ActionListener{
        public void actionPerformed(ActionEvent e)
        {
            Object source = e.getSource();
            //activates showing of the table if that button was pressed
            if(source == callTable)
            {
                currencyTable.go();
                guiLogger.info("Currencies table opened.");
            }
            //activates conversion if that button was pressed
            if(source == convertBtn)
            {
                try
                {
                    String sum = sumField.getText();
                    resultField.setText(reader.convert(sum,fromList.getSelectedIndex(),toList.getSelectedIndex()));
                    guiLogger.info("Conversion was successful!");
                }
                //in case the user entered incorrect amount (0 or below)
                catch(NullSumException n)
                {
                    resultField.setText(n.getMessage());
                    guiLogger.info("User entered zero as the sum.");
                }
            }
        }
    }

    /**
     * Returns the XMLReader object used in the GUI class
     * as it's sub-type Currencies that can be used for logging purposes.
     *
     */
    public Currencies getReader() {return (Currencies) reader;}
    /**
     * Returns the logger of the GUI
     */
    public Logger getLogger() {return guiLogger;}
}