Split tables into individual classes

src/main/java/pl/mikorosa/dziecoin/Main.java

@@ -14,9 +14,9 @@ public class Main {
     public static void main(String[] args) {
         db = new DatabaseConnection();
 
-        System.out.println(db.query("SELECT * FROM blocks"));
-        System.out.println(db.query("SELECT * FROM transactions"));
-        System.out.println(db.query("SELECT * FROM nfts"));
+        System.out.println(db.getBlocksTable().select());
+        System.out.println(db.getTransactionsTable().select());
+        System.out.println(db.getNFTsTable().select());
 
         Wallet w1 = new Wallet();
         Wallet w2 = new Wallet();

src/main/java/pl/mikorosa/dziecoin/database/DatabaseBlocks.java

@@ -0,0 +1,20 @@
+package pl.mikorosa.dziecoin.database;
+
+import pl.mikorosa.dziecoin.Main;
+
+import java.util.List;
+import java.util.Map;
+
+public class DatabaseBlocks extends DatabaseFetchedData {
+    public DatabaseBlocks() {
+        tableName = "blocks";
+    }
+
+    public List<Map<String, Object>> select() {
+        return Main.db.query("SELECT * FROM blocks");
+    }
+
+    public void insert(int height, String hash, String prevHash, int nonce) {
+        Main.db.update("INSERT INTO %s VALUES (%d, '%s', '%s', %d)".formatted(tableName, height, hash, prevHash, nonce));
+    }
+}

src/main/java/pl/mikorosa/dziecoin/database/DatabaseConnection.java

@@ -9,12 +9,19 @@ import java.util.Map;
 public class DatabaseConnection {
     private Connection connection = null;
     private Statement statement = null;
+    private DatabaseBlocks blocks;
+    private DatabaseTransactions transactions;
+    private DatabaseNFTs nfts;
     public DatabaseConnection() {
         System.out.println("Connecting to database...");
         try {
             Class.forName("com.mysql.cj.jdbc.Driver");
             connection = DriverManager.getConnection("jdbc:mysql://helium.mikorosa.pl:3306/dziecoin", "dziecoin", "Y6seMx#HwgYU");
             System.out.println("Connected");
+
+            blocks = new DatabaseBlocks();
+            transactions = new DatabaseTransactions();
+            nfts = new DatabaseNFTs();
         } catch(ClassNotFoundException e) {
             System.out.println("Error while setting up JDBC driver: " + e.getMessage());
             e.printStackTrace();
@@ -24,6 +31,18 @@ public class DatabaseConnection {
         }
     }
 
+    public DatabaseBlocks getBlocksTable() {
+        return blocks;
+    }
+
+    public DatabaseTransactions getTransactionsTable() {
+        return transactions;
+    }
+
+    public DatabaseNFTs getNFTsTable() {
+        return nfts;
+    }
+
     public List<Map<String, Object>> query(String sql) {
         List<Map<String, Object>> list = new ArrayList<>();
         try {

src/main/java/pl/mikorosa/dziecoin/database/DatabaseFetchedData.java

@@ -0,0 +1,19 @@
+package pl.mikorosa.dziecoin.database;
+
+import pl.mikorosa.dziecoin.Main;
+
+import java.util.List;
+import java.util.Map;
+
+public abstract class DatabaseFetchedData {
+    protected String tableName;
+
+    public List<Map<String, Object>> select() {
+        return null;
+    }
+
+    public void cleanTable() {
+        Main.db.deleteAllRecords(tableName);
+        Main.db.resetCounter(tableName);
+    }
+}

src/main/java/pl/mikorosa/dziecoin/database/DatabaseNFTs.java

@@ -0,0 +1,20 @@
+package pl.mikorosa.dziecoin.database;
+
+import pl.mikorosa.dziecoin.Main;
+
+import java.util.List;
+import java.util.Map;
+
+public class DatabaseNFTs extends DatabaseFetchedData {
+    public DatabaseNFTs() {
+        tableName = "nfts";
+    }
+
+    public List<Map<String, Object>> select() {
+        return Main.db.query("SELECT * FROM nfts");
+    }
+
+    public void insert(String contract, String owner, String data, int blockHeight) {
+        Main.db.update("INSERT INTO %s VALUES (null, '%s', '%s', '%s', %d)".formatted(tableName, contract, owner, data, blockHeight));
+    }
+}

src/main/java/pl/mikorosa/dziecoin/database/DatabaseTransactions.java

@@ -0,0 +1,20 @@
+package pl.mikorosa.dziecoin.database;
+
+import pl.mikorosa.dziecoin.Main;
+
+import java.util.List;
+import java.util.Map;
+
+public class DatabaseTransactions extends DatabaseFetchedData {
+    public DatabaseTransactions() {
+        tableName = "transactions";
+    }
+
+    public List<Map<String, Object>> select() {
+        return Main.db.query("SELECT * FROM transactions");
+    }
+
+    public void insert(String sender, String recipient, int amount, int blockHeight) {
+        Main.db.update("INSERT INTO %s VALUES (null, '%s', '%s', %d, %d)".formatted(tableName, sender, recipient, amount, blockHeight));
+    }
+}