Aplikacja "waluty"

pom.xml

@@ -27,6 +27,12 @@
             <version>3.49.1.0</version>
             <scope>runtime</scope>
         </dependency>
+        <dependency>
+            <groupId>org.eclipse.parsson</groupId>
+            <artifactId>jakarta.json</artifactId>
+            <version>1.1.7</version>
+            <!-- starsza wersja: org.glassfish:jakarta.json:2.0.1 -->
+        </dependency>
     </dependencies>
 
 </project>
\ No newline at end of file

src/main/java/bazy/postgresql/P07_GenerowaneId.java

@@ -28,7 +28,7 @@ public class P07_GenerowaneId {
         try(Connection c = DriverManager.getConnection(Ustawienia.URL, Ustawienia.USER, Ustawienia.PASSWD);
          PreparedStatement stmt = c.prepareStatement(sql, polaGenerowane)) {
 
-         stmt.setString(1, "Nowa z " + LocalTime.now().format(DateTimeFormatter.ofPattern("HH:mm:SS")));
+         stmt.setString(1, "Nowa z " + LocalTime.now().format(DateTimeFormatter.ofPattern("HH:mm:ss")));
          stmt.setString(2, "01-321");
          stmt.setString(3, "Warszawa");
          stmt.setString(4, "US");

src/main/java/bazy/postgresql/P08a_ModyfikacjaPoprzezWynik.java

@@ -13,10 +13,8 @@ public class P08a_ModyfikacjaPoprzezWynik {
 
         final String sql = "SELECT * FROM departments WHERE department_id < ? ORDER BY department_id";
         try(Connection c = DriverManager.getConnection(Ustawienia.URL, Ustawienia.USER, Ustawienia.PASSWD)) {
-            
             try(PreparedStatement stmt = c.prepareStatement(sql,
                     ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_UPDATABLE)) {
-
                 stmt.setInt(1, limit);
                 try(ResultSet rs = stmt.executeQuery()) {
                 	System.out.println("Nazwa kursora: " + rs.getCursorName());

src/main/java/bazy/postgresql/P09_DowolnaKolejnoscResultSet.java

@@ -63,7 +63,6 @@ public class P09_DowolnaKolejnoscResultSet {
                                 nazwisko = rs.getString(3);
                                 System.out.printf("         ... a następny ma na nazwisko %s\n", nazwisko);
                             }
-                            
                         } else {
                             System.out.printf("\npoz %3d - nie ma takiej pozycji\n", poz);
                         }

src/main/java/bazy/postgresql/P11_Metadane.java

@@ -19,6 +19,7 @@ public class P11_Metadane {
             System.out.println(dbMetaData.getDatabaseProductName());
             System.out.println(dbMetaData.getDatabaseMajorVersion()
                     + "." + dbMetaData.getDatabaseMinorVersion());
+            System.out.printf("maxStatements: " + dbMetaData.getMaxStatements());
             System.out.println();
             
             try(ResultSet tables = dbMetaData.getTables(null, "public", null, null)) {

src/main/java/bazy/postgresql/P12_MultiResult.java

@@ -12,10 +12,11 @@ public class P12_MultiResult {
         try (Connection c = DriverManager.getConnection(Ustawienia.URL, Ustawienia.USER, Ustawienia.PASSWD)) {
             try (Statement stmt = c.createStatement()) {
                 // Kilka zapytań w jednym stringu
-                String sql = "SELECT * FROM countries;"
-                        + " SELECT * FROM jobs;"
-                        + " SELECT first_name, last_name FROM employees";
-
+                String sql = """
+                        SELECT * FROM countries;
+                        SELECT * FROM jobs;"
+                        SELECT first_name, last_name FROM employees
+                        """;
                 if(stmt.execute(sql)) // jeśli jest pierwszy ResultSet
                 do {
                     try (ResultSet rs = stmt.getResultSet()) {

src/main/java/bazy/postgresql/P13a_Blob_Create.java

@@ -12,7 +12,7 @@ public class P13a_Blob_Create {
 
 	public static void main(String[] args) {
 		final String sql = """
-					DROP TABLE IF EXISTS photos; 
+					DROP TABLE IF EXISTS photos;
 				    CREATE TABLE photos(
 				        photo_id SERIAL PRIMARY KEY,
 				        file_name VARCHAR(60) NOT NULL,

src/main/java/waluty/BladAplikacji.java

+package waluty;
+
+public class BladAplikacji extends Exception {
+
+	public BladAplikacji() {
+		super();
+	}
+
+	public BladAplikacji(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public BladAplikacji(String message) {
+		super(message);
+	}
+
+	public BladAplikacji(Throwable cause) {
+		super(cause);
+	}
+
+}

src/main/java/waluty/DrukujWaluty.java

+package waluty;
+
+public class DrukujWaluty {
+
+    public static void main(String[] args) {
+        // Pobieranie pobieranie = new PobieranieXML();
+        Pobieranie pobieranie = new PobieranieJSON();
+        // Pobieranie pobieranie = Pobieranie.utworz("XML");
+        // Pobieranie pobieranie = Pobieranie.utworz("JSON");
+        try {
+            TabelaWalut tabelaWalut = pobieranie.pobierzBiezaceKursy();
+            System.out.println(tabelaWalut);
+            for(Waluta waluta : tabelaWalut.getRates()) {
+                System.out.println(waluta);
+            }
+        } catch (BladAplikacji e) {
+            e.printStackTrace();
+        }
+    }
+
+}

src/main/java/waluty/Pobieranie.java

+package waluty;
+
+import java.time.LocalDate;
+
+public abstract class Pobieranie {
+
+    protected static final String ADRES_BAZOWY = "https://api.nbp.pl/api/exchangerates/tables";
+
+    public abstract TabelaWalut pobierzBiezaceKursy() throws BladAplikacji;
+
+    public abstract TabelaWalut pobierzArchiwalneKursy(String data) throws BladAplikacji;
+
+    // Jeśli jakaś część implementacji jest wpólna dla wszystkich podklas,
+    // to można umieścić ja w klasie abstrakcyjnej
+    public TabelaWalut pobierzArchiwalneKursy(LocalDate data) throws BladAplikacji {
+        return pobierzArchiwalneKursy(data.toString());
+    }
+
+    // fabryka nowych obiektów
+    public static Pobieranie utworz(String format) {
+        return switch(format.toUpperCase()) {
+            case "XML" -> new PobieranieXML();
+            case "JSON" -> new PobieranieJSON();
+            default -> throw new IllegalArgumentException("Nieznany format " + format);
+        };
+    }
+
+}

src/main/java/waluty/PobieranieJSON.java

+package waluty;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.time.LocalDate;
+
+import jakarta.json.Json;
+import jakarta.json.JsonArray;
+import jakarta.json.JsonObject;
+import jakarta.json.JsonReader;
+import jakarta.json.JsonValue;
+
+public class PobieranieJSON extends Pobieranie {
+
+	public TabelaWalut pobierzBiezaceKursy() throws BladAplikacji {
+		String adres = ADRES_BAZOWY + "/A?format=json";
+		return pobierzZAdresu(adres);
+	}
+
+	public TabelaWalut pobierzArchiwalneKursy(String data) throws BladAplikacji {
+        return pobierzZAdresu(ADRES_BAZOWY + "/A/" + data + "?format=json");
+    }
+
+	private TabelaWalut pobierzZAdresu(String adres) throws BladAplikacji {
+		try(HttpClient httpClient = HttpClient.newHttpClient()) {
+			URI uri = new URI(adres);
+			HttpRequest request = HttpRequest.newBuilder(uri).build();
+			HttpResponse<InputStream> response = httpClient.send(request, BodyHandlers.ofInputStream());
+			if(response.statusCode() != 200) {
+				throw new BladAplikacji("Zapytanie HTTP zwróciło " + response.statusCode());
+			}
+			// dane odebrane z sieci "parsujemy" jako JSON
+			try(JsonReader reader = Json.createReader(response.body())) {
+				JsonArray array = reader.readArray();
+				JsonObject tabela = array.getJsonObject(0);
+				String no = tabela.getString("no");
+				LocalDate effectiveDate = LocalDate.parse(tabela.getString("effectiveDate"));
+				TabelaWalut tabelaWalut = new TabelaWalut(no, effectiveDate);
+
+				JsonArray rates = tabela.getJsonArray("rates");
+				for(JsonValue rate : rates) {
+					JsonObject rateObj = rate.asJsonObject();
+					Waluta waluta = new Waluta(rateObj.getString("code"),
+							rateObj.getString("currency"),
+							rateObj.getJsonNumber("mid").bigDecimalValue());
+					tabelaWalut.addRate(waluta);
+				}
+				return tabelaWalut;
+			}
+		} catch (URISyntaxException | IOException | InterruptedException e) {
+			throw new BladAplikacji(e);
+		}
+	}
+
+}

src/main/java/waluty/PobieranieXML.java

+package waluty;
+
+import java.io.InputStream;
+import java.math.BigDecimal;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+public class PobieranieXML extends Pobieranie {
+    private HttpClient httpClient = HttpClient.newHttpClient();
+    private DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
+    private XPathFactory xpf = XPathFactory.newInstance();
+
+    @Override
+    public TabelaWalut pobierzBiezaceKursy() throws BladAplikacji {
+        return pobierzZAdresu(ADRES_BAZOWY + "/A" + "?format=xml");
+    }
+
+    @Override
+    public TabelaWalut pobierzArchiwalneKursy(String data) throws BladAplikacji {
+        return pobierzZAdresu(ADRES_BAZOWY + "/A/" + data + "?format=xml");
+    }
+
+    private TabelaWalut pobierzZAdresu(String adres) throws BladAplikacji {
+        try {
+            URI uri = new URI(adres);
+            HttpRequest request = HttpRequest.newBuilder(uri).build();
+            HttpResponse<InputStream> response = httpClient.send(request, BodyHandlers.ofInputStream());
+            if(response.statusCode() != 200) {
+                throw new BladAplikacji("Brak danych w odpowiedzi HTTP, kod " + response.statusCode());
+            }
+            DocumentBuilder builder = dbf.newDocumentBuilder();
+            Document document = builder.parse(response.body());
+            return tabelaZXML(document);
+        } catch(BladAplikacji e) {
+            throw e;
+        } catch(Exception e) {
+            throw new BladAplikacji("Błąd podczas pobierania XML: " + e.getMessage(), e);
+        }
+    }
+
+    private TabelaWalut tabelaZXML(Document document) throws XPathExpressionException {
+        XPath xpath = xpf.newXPath();
+
+//        String no = xpath.evaluate("/ArrayOfExchangeRatesTable/ExchangeRatesTable/No", document);
+//        String date = xpath.evaluate("/ArrayOfExchangeRatesTable/ExchangeRatesTable/EffectiveDate", document);
+        String no = xpath.evaluate("//No", document);
+        String date = xpath.evaluate("//EffectiveDate", document);
+        TabelaWalut tabela = new TabelaWalut(no, date);
+
+        NodeList rates = (NodeList) xpath.evaluate("//Rate", document, XPathConstants.NODESET);
+        final int length = rates.getLength();
+        for(int i = 0; i < length; i++) {
+            Node rate = rates.item(i);
+            String currency = xpath.evaluate("Currency", rate);
+            String code = xpath.evaluate("Code", rate);
+            BigDecimal mid = new BigDecimal(xpath.evaluate("Mid", rate));
+            Waluta waluta = new Waluta(code, currency, mid);
+            tabela.addRate(waluta);
+        }
+        return tabela;
+    }
+
+}

src/main/java/waluty/PrzelicznikKonsolowy.java

+
+package waluty;
+
+import java.math.BigDecimal;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.Scanner;
+
+public class PrzelicznikKonsolowy {
+    private Scanner scanner;
+    private Pobieranie pobieranie;
+
+    public PrzelicznikKonsolowy() {
+        scanner = new Scanner(System.in);
+        scanner.useLocale(Locale.US);
+    }
+
+    public static void main(String[] args) {
+        new PrzelicznikKonsolowy().run();
+    }
+
+    public void run() {
+        System.out.println("Wybierz format danych: XML / JSON");
+        String format = scanner.nextLine().trim().toUpperCase();
+        switch(format) {
+            case "XML" -> pobieranie = new PobieranieXML();
+            case "", "JSON" -> pobieranie = new PobieranieJSON();
+            default -> {
+                System.out.println("Nieznany format, kończę program.");
+                return;
+            }
+        }
+
+        program: while(true) {
+            System.out.println("\nWpisz datę w formacie YYYY-MM-DD lub naciśnij ENTER, aby pobrać bieżące kursy.");
+            System.out.println("Możesz też wpisać Q , aby zakończyć program");
+            String data = scanner.nextLine();
+            try {
+                TabelaWalut tabela;
+                switch(data) {
+                    case "q", "Q" -> {break program;}
+                    case "" -> tabela = pobieranie.pobierzBiezaceKursy();
+                    default -> tabela = pobieranie.pobierzArchiwalneKursy(data);
+                }
+                dzialajDlaWybranejTabeli(tabela);
+            } catch(BladAplikacji e) {
+                System.out.println("Wyjątek! " + e.getMessage());
+            }
+        }
+        System.out.println("Koniec programu");
+    }
+
+    private void dzialajDlaWybranejTabeli(TabelaWalut tabela) {
+        System.out.println(tabela);
+
+        while(true) {
+            System.out.println("\nPodaj kod waluty, lub Q aby zakończyć pracę z bieżącą tabelą");
+            String code = scanner.nextLine().toUpperCase();
+            if("Q".equals(code)) {
+                break;
+            }
+            Optional<Waluta> found = tabela.findByCode(code);
+            if(found.isEmpty()) {
+                System.out.println("Nie ma waluty o kodzie " + code);
+                continue;
+            }
+            dzialajDlaWybranejWaluty(found.get());
+        }
+    }
+
+    private void dzialajDlaWybranejWaluty(Waluta waluta) {
+        System.out.println("Wybrana waluta: " + waluta.getCode() + " (" + waluta.getCurrency() + ")" + ", kurs " + waluta.getMid());
+        while(true) {
+            System.out.println("\nPodaj kwotę do przeliczenia. 0 oznacza koniec:");
+            BigDecimal kwota = scanner.nextBigDecimal();
+            scanner.nextLine();
+            if(kwota.compareTo(BigDecimal.ZERO) == 0) {
+                break;
+            }
+            BigDecimal wynikWaluta = waluta.przeliczNaWalute(kwota);
+            BigDecimal wynikPLN = waluta.przeliczNaZlote(kwota);
+
+            System.out.println(kwota + " " + waluta.getCode() + " = " + wynikPLN + " PLN");
+            System.out.println(kwota + " PLN = " + wynikWaluta + " " + waluta.getCode());
+        }
+    }
+
+}

src/main/java/waluty/PrzelicznikWalutOkno.java

+package waluty;
+
+import java.awt.Color;
+import java.awt.EventQueue;
+import java.awt.Font;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.util.Optional;
+
+import javax.swing.ButtonGroup;
+import javax.swing.DefaultComboBoxModel;
+import javax.swing.GroupLayout;
+import javax.swing.GroupLayout.Alignment;
+import javax.swing.JButton;
+import javax.swing.JComboBox;
+import javax.swing.JFrame;
+import javax.swing.JLabel;
+import javax.swing.JPanel;
+import javax.swing.JRadioButton;
+import javax.swing.JTextField;
+import javax.swing.LayoutStyle.ComponentPlacement;
+import javax.swing.SwingConstants;
+import javax.swing.SwingUtilities;
+import javax.swing.SwingWorker;
+
+public class PrzelicznikWalutOkno {
+
+	private static final Font FONT_LABEL = new Font("Times New Roman", Font.PLAIN, 24);
+	private static final Font FONT_WARTOSC = new Font("Dialog", Font.BOLD, 24);
+	private static final Font FONT_TXT = new Font("Dialog", Font.BOLD, 32);
+	private static final Font FONT_WYNIK = new Font("Dialog", Font.BOLD, 32);
+	private static final Font FONT_BUTTON = new Font("Dialog", Font.BOLD, 28);
+
+	private TabelaWalut tabela = null;
+	private JFrame frmPrzelicznikWalut;
+	private JTextField txtKwota;
+	private JComboBox<String> comboBox_Waluta;
+	private JLabel lbl_KodWaluty;
+	private JLabel lbl_NazwaWaluty;
+	private JLabel lbl_KursWaluty;
+	private JRadioButton rdbtnWalutaNaZlote;
+	private JRadioButton rdbtnZloteNaWalute;
+	private JButton btnPrzelicz;
+	private JLabel lblPrawdziwyWynik;
+	private final ButtonGroup buttonGroup = new ButtonGroup();
+	private JPanel panel_1;
+	private JLabel lblTabela;
+	private JLabel lbl_NumerTabeli;
+	private JLabel lblData;
+	private JLabel lbl_DataTabeli;
+	private JTextField txtData;
+	private JButton btnPobierzAktualne;
+	private Pobieranie pobieranie = Pobieranie.utworz("xml");
+
+	/**
+	 * Launch the application.
+	 */
+	public static void main(String[] args) {
+		EventQueue.invokeLater(new Runnable() {
+			public void run() {
+				try {
+					// com.formdev.flatlaf.FlatDarkLaf.setup();
+					PrzelicznikWalutOkno window = new PrzelicznikWalutOkno();
+					window.txtData.setText(LocalDate.now().toString());
+					window.frmPrzelicznikWalut.setVisible(true);
+					window.pobierzAktualneKursy();
+				} catch (Exception e) {
+					e.printStackTrace();
+				}
+			}
+		});
+	}
+
+	/**
+	 * Create the application.
+	 */
+	public PrzelicznikWalutOkno() {
+		initialize();
+	}
+
+	/**
+	 * Initialize the contents of the frame.
+	 */
+	private void initialize() {
+		frmPrzelicznikWalut = new JFrame();
+		frmPrzelicznikWalut.setTitle("Przelicznik Walut");
+		frmPrzelicznikWalut.setBounds(100, 100, 480, 701);
+		frmPrzelicznikWalut.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+
+		JLabel lblWybierzWalut = new JLabel("Wybierz walutę");
+		lblWybierzWalut.setFont(FONT_LABEL);
+
+		comboBox_Waluta = new JComboBox<>();
+		comboBox_Waluta.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent ev) {
+				wyswietlDaneWaluty();
+			}
+		});
+		comboBox_Waluta.setModel(
+				new DefaultComboBoxModel<>(new String[] {"--"}));
+
+		comboBox_Waluta.setFont(FONT_WARTOSC);
+
+		JPanel panel = new JPanel();
+
+		txtKwota = new JTextField();
+		txtKwota.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent ev) {
+				przelicz();
+			}
+		});
+		txtKwota.setText("100");
+		txtKwota.setColumns(10);
+		txtKwota.setFont(FONT_TXT);
+
+		JLabel lblPodajKwot = new JLabel("Podaj kwotę");
+		lblPodajKwot.setFont(FONT_LABEL);
+
+		rdbtnWalutaNaZlote = new JRadioButton("waluta na złote");
+		rdbtnWalutaNaZlote.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent ev) {
+				przelicz();
+			}
+		});
+		rdbtnWalutaNaZlote.setFont(FONT_LABEL);
+
+		buttonGroup.add(rdbtnWalutaNaZlote);
+
+		rdbtnZloteNaWalute = new JRadioButton("złote na walute");
+		rdbtnZloteNaWalute.setFont(FONT_LABEL);
+		rdbtnZloteNaWalute.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent ev) {
+				przelicz();
+			}
+		});
+		buttonGroup.add(rdbtnZloteNaWalute);
+
+		btnPrzelicz = new JButton("Przelicz");
+		btnPrzelicz.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent ev) {
+				przelicz();
+			}
+		});
+		btnPrzelicz.setFont(FONT_BUTTON);
+
+		JLabel lblWynik = new JLabel("Wynik");
+		lblWynik.setFont(FONT_LABEL);
+
+		lblPrawdziwyWynik = new JLabel("0.00");
+		lblPrawdziwyWynik.setFont(FONT_WYNIK);
+		lblPrawdziwyWynik.setForeground(Color.GRAY);
+
+		panel_1 = new JPanel();
+
+		JLabel lblPodajDat = new JLabel("Podaj datę");
+		lblPodajDat.setFont(FONT_LABEL);
+
+		txtData = new JTextField();
+		txtData.setHorizontalAlignment(SwingConstants.CENTER);
+		txtData.setFont(new Font("Dialog", Font.PLAIN, 20));
+		txtData.setText("data");
+		txtData.setColumns(10);
+
+		JButton btnZmieDat = new JButton("Zmień datę");
+		btnZmieDat.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent e) {
+				pobierzKursyDlaDaty();
+			}
+		});
+		btnZmieDat.setFont(new Font("Dialog", Font.BOLD, 18));
+
+		btnPobierzAktualne = new JButton("Pobierz aktualne");
+		btnPobierzAktualne.addActionListener(new ActionListener() {
+			public void actionPerformed(ActionEvent e) {
+				pobierzAktualneKursy();
+			}
+		});
+		btnPobierzAktualne.setFont(new Font("Dialog", Font.BOLD, 18));
+
+		GroupLayout groupLayout = new GroupLayout(frmPrzelicznikWalut.getContentPane());
+		groupLayout.setHorizontalGroup(
+			groupLayout.createParallelGroup(Alignment.LEADING)
+				.addGroup(groupLayout.createSequentialGroup()
+					.addContainerGap()
+					.addGroup(groupLayout.createParallelGroup(Alignment.TRAILING)
+						.addComponent(panel_1, Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 448, Short.MAX_VALUE)
+						.addComponent(btnPrzelicz, Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 448, Short.MAX_VALUE)
+						.addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
+							.addComponent(rdbtnWalutaNaZlote)
+							.addPreferredGap(ComponentPlacement.RELATED, 108, Short.MAX_VALUE)
+							.addComponent(rdbtnZloteNaWalute))
+						.addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
+							.addComponent(lblPodajKwot)
+							.addPreferredGap(ComponentPlacement.RELATED, 139, Short.MAX_VALUE)
+							.addComponent(txtKwota, GroupLayout.PREFERRED_SIZE, 189, GroupLayout.PREFERRED_SIZE))
+						.addComponent(panel, Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 448, Short.MAX_VALUE)
+						.addComponent(lblWynik, Alignment.LEADING)
+						.addComponent(lblPrawdziwyWynik, Alignment.LEADING)
+						.addGroup(Alignment.LEADING, groupLayout.createSequentialGroup()
+							.addGroup(groupLayout.createParallelGroup(Alignment.TRAILING, false)
+								.addComponent(lblPodajDat, Alignment.LEADING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
+								.addComponent(lblWybierzWalut, Alignment.LEADING, GroupLayout.DEFAULT_SIZE, 223, Short.MAX_VALUE))
+							.addPreferredGap(ComponentPlacement.UNRELATED)
+							.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
+								.addComponent(txtData, GroupLayout.DEFAULT_SIZE, 207, Short.MAX_VALUE)
+								.addComponent(comboBox_Waluta, 0, 207, Short.MAX_VALUE)))
+						.addGroup(groupLayout.createSequentialGroup()
+							.addComponent(btnPobierzAktualne, GroupLayout.PREFERRED_SIZE, 207, GroupLayout.PREFERRED_SIZE)
+							.addGap(34)
+							.addComponent(btnZmieDat, GroupLayout.DEFAULT_SIZE, 207, Short.MAX_VALUE)))
+					.addContainerGap())
+		);
+		groupLayout.setVerticalGroup(
+			groupLayout.createParallelGroup(Alignment.TRAILING)
+				.addGroup(groupLayout.createSequentialGroup()
+					.addContainerGap()
+					.addComponent(panel_1, GroupLayout.PREFERRED_SIZE, 103, GroupLayout.PREFERRED_SIZE)
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addGroup(groupLayout.createParallelGroup(Alignment.LEADING, false)
+						.addComponent(txtData, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+						.addComponent(lblPodajDat, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
+					.addPreferredGap(ComponentPlacement.RELATED)
+					.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
+						.addComponent(btnZmieDat)
+						.addComponent(btnPobierzAktualne, GroupLayout.PREFERRED_SIZE, 32, GroupLayout.PREFERRED_SIZE))
+					.addPreferredGap(ComponentPlacement.RELATED, 17, Short.MAX_VALUE)
+					.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
+						.addComponent(comboBox_Waluta, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+						.addComponent(lblWybierzWalut))
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addComponent(panel, GroupLayout.PREFERRED_SIZE, 142, GroupLayout.PREFERRED_SIZE)
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
+						.addComponent(txtKwota, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
+						.addComponent(lblPodajKwot))
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addGroup(groupLayout.createParallelGroup(Alignment.BASELINE)
+						.addComponent(rdbtnWalutaNaZlote)
+						.addComponent(rdbtnZloteNaWalute))
+					.addPreferredGap(ComponentPlacement.RELATED)
+					.addComponent(btnPrzelicz)
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addComponent(lblWynik)
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addComponent(lblPrawdziwyWynik)
+					.addGap(33))
+		);
+
+		lblTabela = new JLabel("Tabela");
+		lblTabela.setFont(FONT_LABEL);
+
+		lbl_NumerTabeli = new JLabel("?");
+		lbl_NumerTabeli.setFont(new Font("Dialog", Font.BOLD, 24));
+
+		lblData = new JLabel("Data:");
+		lblData.setFont(FONT_LABEL);
+
+		lbl_DataTabeli = new JLabel("?");
+		lbl_DataTabeli.setFont(new Font("Dialog", Font.BOLD, 24));
+
+		GroupLayout gl_panel_1 = new GroupLayout(panel_1);
+		gl_panel_1.setHorizontalGroup(
+			gl_panel_1.createParallelGroup(Alignment.LEADING)
+				.addGroup(gl_panel_1.createSequentialGroup()
+					.addContainerGap()
+					.addGroup(gl_panel_1.createParallelGroup(Alignment.LEADING)
+						.addGroup(gl_panel_1.createSequentialGroup()
+							.addComponent(lblTabela, GroupLayout.PREFERRED_SIZE, 95, GroupLayout.PREFERRED_SIZE)
+							.addGap(18)
+							.addComponent(lbl_NumerTabeli, GroupLayout.PREFERRED_SIZE, 311, GroupLayout.PREFERRED_SIZE))
+						.addGroup(gl_panel_1.createSequentialGroup()
+							.addComponent(lblData, GroupLayout.PREFERRED_SIZE, 95, GroupLayout.PREFERRED_SIZE)
+							.addGap(18)
+							.addComponent(lbl_DataTabeli, GroupLayout.PREFERRED_SIZE, 311, GroupLayout.PREFERRED_SIZE)))
+					.addContainerGap(GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
+		);
+		gl_panel_1.setVerticalGroup(
+			gl_panel_1.createParallelGroup(Alignment.LEADING)
+				.addGroup(gl_panel_1.createSequentialGroup()
+					.addContainerGap()
+					.addGroup(gl_panel_1.createParallelGroup(Alignment.LEADING)
+						.addComponent(lblTabela, GroupLayout.PREFERRED_SIZE, 29, GroupLayout.PREFERRED_SIZE)
+						.addComponent(lbl_NumerTabeli, GroupLayout.PREFERRED_SIZE, 29, GroupLayout.PREFERRED_SIZE))
+					.addGap(12)
+					.addGroup(gl_panel_1.createParallelGroup(Alignment.LEADING)
+						.addComponent(lblData, GroupLayout.PREFERRED_SIZE, 29, GroupLayout.PREFERRED_SIZE)
+						.addComponent(lbl_DataTabeli, GroupLayout.PREFERRED_SIZE, 29, GroupLayout.PREFERRED_SIZE))
+					.addContainerGap(21, Short.MAX_VALUE))
+		);
+		panel_1.setLayout(gl_panel_1);
+
+		JLabel lblKod = new JLabel("Kod:");
+		lblKod.setFont(FONT_LABEL);
+
+		JLabel lblNazwa = new JLabel("Nazwa:");
+		lblNazwa.setFont(FONT_LABEL);
+
+		JLabel lblKurs = new JLabel("Kurs:");
+		lblKurs.setFont(FONT_LABEL);
+
+		lbl_KodWaluty = new JLabel("kod");
+		lbl_KodWaluty.setFont(FONT_WARTOSC);
+
+		lbl_NazwaWaluty = new JLabel("nazwa");
+		lbl_NazwaWaluty.setFont(FONT_WARTOSC);
+
+		lbl_KursWaluty = new JLabel("1.0000");
+		lbl_KursWaluty.setFont(FONT_WARTOSC);
+
+		GroupLayout gl_panel = new GroupLayout(panel);
+		gl_panel.setHorizontalGroup(
+			gl_panel.createParallelGroup(Alignment.LEADING)
+				.addGroup(gl_panel.createSequentialGroup()
+					.addContainerGap()
+					.addGroup(gl_panel.createParallelGroup(Alignment.LEADING, false)
+						.addComponent(lblKurs, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
+						.addComponent(lblNazwa, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
+						.addComponent(lblKod, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, 95, Short.MAX_VALUE))
+					.addPreferredGap(ComponentPlacement.RELATED, 18, GroupLayout.PREFERRED_SIZE)
+					.addGroup(gl_panel.createParallelGroup(Alignment.LEADING)
+						.addComponent(lbl_KodWaluty, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, 171, Short.MAX_VALUE)
+						.addComponent(lbl_NazwaWaluty, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, 171, Short.MAX_VALUE)
+						.addComponent(lbl_KursWaluty, Alignment.TRAILING, GroupLayout.DEFAULT_SIZE, 171, Short.MAX_VALUE))
+					.addContainerGap())
+		);
+		gl_panel.setVerticalGroup(
+			gl_panel.createParallelGroup(Alignment.LEADING)
+				.addGroup(gl_panel.createSequentialGroup()
+					.addContainerGap()
+					.addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
+						.addComponent(lblKod)
+						.addComponent(lbl_KodWaluty))
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
+						.addComponent(lblNazwa)
+						.addComponent(lbl_NazwaWaluty))
+					.addPreferredGap(ComponentPlacement.UNRELATED)
+					.addGroup(gl_panel.createParallelGroup(Alignment.BASELINE)
+						.addComponent(lblKurs)
+						.addComponent(lbl_KursWaluty))
+					.addContainerGap(61, Short.MAX_VALUE))
+		);
+		panel.setLayout(gl_panel);
+		frmPrzelicznikWalut.getContentPane().setLayout(groupLayout);
+	}
+
+	protected void przelicz() {
+		try {
+			BigDecimal kwota = new BigDecimal(txtKwota.getText());
+			String kod = "" + comboBox_Waluta.getSelectedItem();
+			Waluta waluta = tabela.findByCode(kod).get();
+			BigDecimal wynik = null;
+			if(rdbtnWalutaNaZlote.isSelected()) {
+				wynik = waluta.przeliczNaZlote(kwota);
+			}
+			if(rdbtnZloteNaWalute.isSelected()) {
+				wynik = waluta.przeliczNaWalute(kwota);
+			}
+			lblPrawdziwyWynik.setText("" + wynik);
+			lblPrawdziwyWynik.setForeground(Color.BLUE);
+		} catch (Exception e) {
+			lblPrawdziwyWynik.setText("błąd");
+			lblPrawdziwyWynik.setForeground(Color.RED);
+		}
+	}
+
+	protected void wyswietlDaneWaluty() {
+		String kod = "" + comboBox_Waluta.getSelectedItem();
+		Optional<Waluta> waluta = tabela.findByCode(kod);
+		if(waluta.isPresent()) {
+			lbl_KodWaluty.setText(waluta.get().getCode());
+			lbl_NazwaWaluty.setText(waluta.get().getCurrency());
+			lbl_KursWaluty.setText("" + waluta.get().getMid());
+			if(! txtKwota.getText().isEmpty()) {
+				przelicz();
+			}
+			return;
+		}
+		lblPrawdziwyWynik.setText("0.00");
+		lblPrawdziwyWynik.setForeground(Color.GRAY);
+	}
+
+	private void pobierzAktualneKursy() {
+		// Pobieranie aktualnych kursów w tle (to znaczy w innym wątku)
+		// Aby wykonać operację w tle, w Swingu najlepiej użyć klasy SwingWorker
+
+		SwingWorker<TabelaWalut, Void> worker = new SwingWorker<>() {
+			protected TabelaWalut doInBackground() {
+				try {
+                    tabela = pobieranie.pobierzBiezaceKursy();
+                } catch(BladAplikacji e) {
+                    tabela = new TabelaWalut("Brak danych", LocalDate.now());
+                    e.printStackTrace();
+                }
+				return tabela;
+			}
+
+			protected void done() {
+				// tu piszemy "co ma zrobić okno, gdy operacja jest zakończona"
+				// to będzie wykonane przez wątek EDT
+				odswiezDaneTabeli();
+				wyswietlDaneWaluty();
+			}
+		};
+
+		worker.execute();
+	}
+
+	private void pobierzKursyDlaDaty() {
+		SwingWorker<TabelaWalut, Void> worker = new SwingWorker<>() {
+			protected TabelaWalut doInBackground() {
+				String data = txtData.getText();
+				try {
+				    tabela = pobieranie.pobierzArchiwalneKursy(data);
+				    SwingUtilities.invokeLater(() -> {
+				        txtData.setForeground(Color.BLACK);
+				    });
+                } catch(BladAplikacji e) {
+                    tabela = new TabelaWalut("Brak danych", LocalDate.now());
+                    e.printStackTrace();
+                }
+				return tabela;
+			}
+
+			protected void done() {
+				odswiezDaneTabeli();
+				wyswietlDaneWaluty();
+			}
+		};
+
+		worker.execute();
+	}
+
+	private void odswiezDaneTabeli() {
+		lbl_NumerTabeli.setText(tabela.getNo());
+		lbl_DataTabeli.setText("" + tabela.getEffectiveDate());
+		Object wybranaWaluta = comboBox_Waluta.getSelectedItem();
+		comboBox_Waluta.setModel(new DefaultComboBoxModel<>(tabela.codes()));
+		comboBox_Waluta.setSelectedItem(wybranaWaluta);
+	}
+}

src/main/java/waluty/TabelaWalut.java

+package waluty;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+public class TabelaWalut {
+	private final String no;
+	private final LocalDate effectiveDate;
+	private final List<Waluta> rates = new ArrayList<>();
+
+	public TabelaWalut(String no, LocalDate effectiveDate) {
+		this.no = no;
+		this.effectiveDate = effectiveDate;
+	}
+
+    public TabelaWalut(String no, String effectiveDate) {
+        this(no, LocalDate.parse(effectiveDate));
+    }
+
+    public void addRate(Waluta waluta) {
+        rates.add(waluta);
+    }
+
+    public String getNo() {
+        return no;
+    }
+
+    public LocalDate getEffectiveDate() {
+        return effectiveDate;
+    }
+
+    public List<Waluta> getRates() {
+        // dostęp tylko do odczytu
+        return Collections.unmodifiableList(rates);
+    }
+
+    @Override
+    public String toString() {
+        return "Tabela nr " + no + " z dnia " + effectiveDate + ", " + rates.size() + " walut";
+    }
+
+    public Optional<Waluta> findByCode(String code) {
+        for(Waluta waluta : rates) {
+            if(waluta.getCode().equals(code) ) {
+                return Optional.of(waluta);
+            }
+        }
+        return Optional.empty();
+    }
+
+    public String[] codes() {
+        return rates.stream()
+        		.map(Waluta::getCode)
+        		.toArray(String[]::new);
+    }
+
+}

src/main/java/waluty/Waluta.java

+package waluty;
+
+import java.math.BigDecimal;
+import java.math.RoundingMode;
+
+public class Waluta {
+	private final String code;
+	private final String currency;
+	private final BigDecimal mid;
+
+	public Waluta(String code, String currency, BigDecimal mid) {
+		this.code = code;
+		this.currency = currency;
+		this.mid = mid;
+	}
+
+	public String getCode() {
+		return code;
+	}
+
+	public String getCurrency() {
+		return currency;
+	}
+
+	public BigDecimal getMid() {
+		return mid;
+	}
+
+	@Override
+	public String toString() {
+		return code + " (" + currency + "): " + mid;
+	}
+
+	public BigDecimal przeliczNaZlote(BigDecimal kwota) {
+		return kwota.multiply(mid).setScale(2, RoundingMode.HALF_EVEN);
+	}
+
+	public BigDecimal przeliczNaWalute(BigDecimal kwota) {
+		return kwota.divide(mid, 2, RoundingMode.HALF_EVEN);
+	}
+
+}

src/main/java/waluty/linki_nbp.txt

+https://api.nbp.pl/
+
+https://api.nbp.pl/api/exchangerates/tables/A/
+
+https://api.nbp.pl/api/exchangerates/tables/B/
+https://api.nbp.pl/api/exchangerates/tables/C/
+
+https://api.nbp.pl/api/exchangerates/tables/A/2020-02-05
+
+https://api.nbp.pl/api/exchangerates/tables/A/?format=xml
+
+https://api.nbp.pl/api/exchangerates/tables/A/?format=json