feat: add advanced multithreading banking system skeleton

src/main/java/dev/banking/processor/TransactionProcessor.java

@@ -0,0 +1,44 @@
+package dev.banking.processor;
+
+import dev.banking.model.*;
+
+import java.util.Map;
+
+public class TransactionProcessor {
+
+    private final Map<Integer, BankAccount> accounts;
+
+    public TransactionProcessor(
+            Map<Integer, BankAccount> accounts
+    ) {
+        this.accounts = accounts;
+    }
+
+    public void process(Transaction tx) {
+
+        BankAccount source =
+                accounts.get(tx.getSourceAccountId());
+
+        switch (tx.getType()) {
+
+            case DEPOSIT -> {
+                source.deposit(tx.getAmount());
+            }
+
+            case WITHDRAW -> {
+                source.withdraw(tx.getAmount());
+            }
+
+            case TRANSFER -> {
+
+                BankAccount target =
+                        accounts.get(tx.getTargetAccountId());
+
+                source.transfer(
+                        target,
+                        tx.getAmount()
+                );
+            }
+        }
+    }
+}