Add DAO Ingredients

WEB-INF/src/DAO/DAOIngredients.java

 package DAO;
+import POJO.Ingredient;
+
+import java.sql.*;
+import java.util.ArrayList;
+import java.util.List;
 
 public class DAOIngredients {
+    // JDBC URL, username, and password of PostgresSQL server
+    private static final String url = "jdbc:postgresql://"; //CHANGE URL
+    private static final String user = "gwendalmargelyetu";
+    private static final String password = "moi";
+
+    // JDBC variables for opening, closing and managing connection
+    private static Connection connection;
+    private static PreparedStatement preparedStatement;
+    private static ResultSet resultSet;
+
+    // SQL queries
+    private static final String SELECT_ALL_QUERY = "SELECT * FROM ingredients";
+    private static final String INSERT_QUERY = "INSERT INTO ingredients(name, price) VALUES (?, ?)";
+    private static final String SELECT_BY_ID_QUERY = "SELECT * FROM ingredients WHERE id = ?";
+
+    // Method to establish database connection
+    private static void connect() throws SQLException {
+        connection = DriverManager.getConnection(url, user, password);
+    }
+
+    // Method to close database connection
+    private static void close() throws SQLException {
+        if (resultSet != null) {
+            resultSet.close();
+        }
+        if (preparedStatement != null) {
+            preparedStatement.close();
+        }
+        if (connection != null) {
+            connection.close();
+        }
+    }
+
+    // Method to retrieve all ingredients from the database
+    public static List<Ingredient> getAllIngredients() throws SQLException {
+        List<Ingredient> ingredients = new ArrayList<>();
+        connect();
+        preparedStatement = connection.prepareStatement(SELECT_ALL_QUERY);
+        resultSet = preparedStatement.executeQuery();
+
+        while (resultSet.next()) {
+            int id = resultSet.getInt("id");
+            String name = resultSet.getString("name");
+            double price = resultSet.getDouble("price");
+            Ingredient ingredient = new Ingredient(id, name, price);
+            ingredients.add(ingredient);
+        }
+
+        close();
+        return ingredients;
+    }
+
+    // Method to insert a new ingredient into the database
+    public static void insertIngredient(Ingredient ingredient) throws SQLException {
+        connect();
+        preparedStatement = connection.prepareStatement(INSERT_QUERY);
+        preparedStatement.setString(1, ingredient.getName());
+        preparedStatement.setDouble(2, ingredient.getPrice());
+        preparedStatement.executeUpdate();
+        close();
+    }
+
+    // Method to retrieve an ingredient by its ID
+    public static Ingredient getIngredient(int id) throws SQLException {
+        connect();
+        preparedStatement = connection.prepareStatement(SELECT_BY_ID_QUERY);
+        preparedStatement.setInt(1, id);
+        resultSet = preparedStatement.executeQuery();
+
+        Ingredient ingredient = null;
+        if (resultSet.next()) {
+            String name = resultSet.getString("name");
+            double price = resultSet.getDouble("price");
+            ingredient = new Ingredient(id, name, price);
+        }
+
+        close();
+        return ingredient;
+    }
 }

WEB-INF/src/POJO/Ingredient.java

@@ -3,18 +3,16 @@ package POJO;
 public class Ingredient {
     public int id;
     private String name;
-    private Price price;
+    private double price;
 
-    public Ingredient(int id, String name, Price price) {
+    public Ingredient(int id, String name, double price) {
         this.id = id;
         this.name = name;
         this.price = price;
     }
 
     public Ingredient(int id, String name) {
-        this.id = id;
-        this.name = name;
-        this.price = new Price();
+        this(id, name, 0.00);
     }
 
     public int getId() {
@@ -33,11 +31,11 @@ public class Ingredient {
         this.name = name;
     }
 
-    public Price getPrice() {
+    public double getPrice() {
         return price;
     }
 
-    public void setPrice(Price price) {
+    public void setPrice(double price) {
         this.price = price;
     }
 }