bais-policy-e2e-1783705261/src/main/java/com/example/baispolicy/PaymentService.java

package com.example.baispolicy;

public class PaymentService {
    public String approve(String transactionId) {
        if (transactionId == null || transactionId.isBlank()) {
            throw new IllegalArgumentException("Transaction ID must not be blank.");
        }
        return "APPROVED:" + transactionId;
    }
}