feat: implement exception hierarchy and ExceptionTranslator

src/main/java/org/example/database/exception/DatabaseException.java

@@ -0,0 +1,8 @@
+package org.example.database.exception;
+
+public class DatabaseException extends OrmException {
+
+    public DatabaseException(String message) {
+        super(message);
+    }
+}

src/main/java/org/example/database/exception/DuplicateKeyException.java

@@ -0,0 +1,8 @@
+package org.example.database.exception;
+
+public class DuplicateKeyException extends OrmException {
+
+    public DuplicateKeyException(String message) {
+        super(message);
+    }
+}

src/main/java/org/example/database/exception/EntityNotFoundException.java

@@ -0,0 +1,8 @@
+package org.example.database.exception;
+
+public class EntityNotFoundException extends OrmException {
+
+    public EntityNotFoundException(String message) {
+        super(message);
+    }
+}

src/main/java/org/example/database/exception/EntityValidationException.java

@@ -0,0 +1,8 @@
+package org.example.database.exception;
+
+public class EntityValidationException extends OrmException {
+
+    public EntityValidationException(String message) {
+        super(message);
+    }
+}

src/main/java/org/example/database/exception/ExceptionTranslator.java

@@ -0,0 +1,43 @@
+package org.example.database.exception;
+
+import java.sql.SQLException;
+
+public class ExceptionTranslator {
+
+    private static final String UNIQUE_VIOLATION_CODE = "23505";
+
+    public static OrmException translate(SQLException e, Class<?> entityClass, String sql) {
+        String sqlState = e.getSQLState();
+
+        if (UNIQUE_VIOLATION_CODE.equals(sqlState)) {
+            String constraintName = extractConstraintName(e);
+            String message = String.format("Duplicate key violation on entity '%s': unique constraint '%s'",
+                    entityClass != null ? entityClass.getSimpleName() : "unknown",
+                    constraintName);
+            return new DuplicateKeyException(message);
+        }
+
+        if (sqlState != null && sqlState.startsWith("23")) {
+            String message = String.format("Database error executing query '%s': %s", sql, e.getMessage());
+            return new DatabaseException(message);
+        }
+
+        String message = String.format("Database error executing query '%s': %s", sql, e.getMessage());
+        return new DatabaseException(message);
+    }
+
+    private static String extractConstraintName(SQLException e) {
+        String message = e.getMessage();
+        if (message != null && message.contains("unique constraint")) {
+            int start = message.lastIndexOf("unique constraint \"");
+            if (start != -1) {
+                start += "unique constraint \"".length();
+                int end = message.indexOf("\"", start);
+                if (end > start) {
+                    return message.substring(start, end);
+                }
+            }
+        }
+        return "unknown";
+    }
+}

src/main/java/org/example/database/exception/OrmException.java

@@ -0,0 +1,8 @@
+package org.example.database.exception;
+
+public class OrmException extends RuntimeException {
+
+    public OrmException(String message) {
+        super(message);
+    }
+}