From 0ec9bd598673aaa59cadf88b29a4066e48013375 Mon Sep 17 00:00:00 2001
From: Solveig Natvig <solveig.natvig@gmail.com>
Date: Fri, 20 Feb 2026 12:52:46 +0100
Subject: [PATCH] Add TransactionCalculator interface

---
 src/main/java/TransactionCalculator.java | 9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 src/main/java/TransactionCalculator.java

diff --git a/src/main/java/TransactionCalculator.java b/src/main/java/TransactionCalculator.java
new file mode 100644
index 0000000..dd17eef
--- /dev/null
+++ b/src/main/java/TransactionCalculator.java
@@ -0,0 +1,9 @@
+import java.math.BigDecimal;
+
+public interface TransactionCalculator {
+    // Methods in interface is automatically public abstract.
+    BigDecimal calculateGross();
+    BigDecimal calculateCommission();
+    BigDecimal calculateTax();
+    BigDecimal calculateTotal();
+}