feat: add payment processor for new transaction flow

.github/workflows/sonarcloud-devin.yml

@@ -48,6 +48,10 @@ jobs:
           key: ${{ runner.os }}-sonar
           restore-keys: ${{ runner.os }}-sonar
 
+      - name: Build demo module and run tests
+        run: |
+          cd demo && mvn clean test jacoco:report -q
+
       - name: SonarQube Scan
         run: |
           # Using sonar-scanner CLI for flexibility
@@ -56,9 +60,7 @@ jobs:
           ./sonar-scanner-5.0.1.3006-linux/bin/sonar-scanner \
             -Dsonar.projectKey=${{ env.SONAR_PROJECT_KEY }} \
             -Dsonar.organization=${{ env.SONAR_ORG }} \
-            -Dsonar.host.url=https://sonarcloud.io \
-            -Dsonar.sources=. \
-            -Dsonar.java.binaries=.
+            -Dsonar.host.url=https://sonarcloud.io
 
       - name: Quality Gate Check
         id: quality-gate

demo/pom.xml

@@ -0,0 +1,99 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.banking</groupId>
+    <artifactId>demo</artifactId>
+    <version>1.0-SNAPSHOT</version>
+    <packaging>jar</packaging>
+
+    <name>Banking Demo</name>
+    <description>Demo module for payment processing</description>
+
+    <properties>
+        <maven.compiler.source>17</maven.compiler.source>
+        <maven.compiler.target>17</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <junit.version>5.10.0</junit.version>
+        <mockito.version>5.5.0</mockito.version>
+        <jacoco.version>0.8.11</jacoco.version>
+        <sonar.organization>samfert-codeium</sonar.organization>
+        <sonar.host.url>https://sonarcloud.io</sonar.host.url>
+    </properties>
+
+    <dependencies>
+        <!-- MySQL Connector for JDBC -->
+        <dependency>
+            <groupId>com.mysql</groupId>
+            <artifactId>mysql-connector-j</artifactId>
+            <version>8.1.0</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- JUnit 5 -->
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <!-- Mockito -->
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <version>${mockito.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.11.0</version>
+                <configuration>
+                    <source>17</source>
+                    <target>17</target>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>3.1.2</version>
+            </plugin>
+
+            <plugin>
+                <groupId>org.jacoco</groupId>
+                <artifactId>jacoco-maven-plugin</artifactId>
+                <version>${jacoco.version}</version>
+                <executions>
+                    <execution>
+                        <id>prepare-agent</id>
+                        <goals>
+                            <goal>prepare-agent</goal>
+                        </goals>
+                    </execution>
+                    <execution>
+                        <id>report</id>
+                        <phase>test</phase>
+                        <goals>
+                            <goal>report</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

demo/src/main/java/demo/PaymentProcessor.java

@@ -0,0 +1,104 @@
+package demo;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.PreparedStatement;
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+import java.util.logging.Logger;
+
+/**
+ * Payment Processor - handles payment transactions
+ */
+public class PaymentProcessor {
+
+    private static final Logger LOGGER = Logger.getLogger(PaymentProcessor.class.getName());
+
+    // Database credentials from environment variables with defaults
+    private static final String DB_URL = getEnvOrDefault("DB_URL", "jdbc:mysql://localhost:3306/payments");
+    private static final String DB_USER = getEnvOrDefault("DB_USER", "payment_admin");
+    private static final String DB_PASSWORD = getEnvOrDefault("DB_PASSWORD", "");
+
+    private static String getEnvOrDefault(String key, String defaultValue) {
+        String value = System.getenv(key);
+        return value != null ? value : defaultValue;
+    }
+
+    // Reusable SecureRandom instance for cryptographically secure random numbers
+    private static final SecureRandom SECURE_RANDOM = new SecureRandom();
+
+    /**
+     * Process a payment using parameterized queries
+     */
+    public boolean processPayment(String accountId, String amount, String description) {
+        String sql = "INSERT INTO payments (account_id, amount, description) VALUES (?, ?, ?)";
+
+        try (Connection conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWORD);
+             PreparedStatement stmt = conn.prepareStatement(sql)) {
+
+            stmt.setString(1, accountId);
+            stmt.setString(2, amount);
+            stmt.setString(3, description);
+            stmt.executeUpdate();
+
+            return true;
+        } catch (java.sql.SQLException e) {
+            LOGGER.warning("SQL error processing payment: " + e.getMessage());
+            return false;
+        }
+    }
+
+    /**
+     * Verify payment signature using SHA-256
+     */
+    public String hashPaymentData(String data) {
+        try {
+            MessageDigest md = MessageDigest.getInstance("SHA-256");
+            byte[] hash = md.digest(data.getBytes());
+            StringBuilder hexString = new StringBuilder();
+            for (byte b : hash) {
+                hexString.append(String.format("%02x", b));
+            }
+            return hexString.toString();
+        } catch (java.security.NoSuchAlgorithmException e) {
+            LOGGER.warning("Hashing algorithm not found: " + e.getMessage());
+            return null;
+        }
+    }
+
+    /**
+     * Generate transaction ID using reusable SecureRandom instance
+     */
+    public String generateTransactionId() {
+        return "TXN-" + SECURE_RANDOM.nextInt(999999999);
+    }
+
+    /**
+     * Validate account with null safety
+     */
+    public boolean validateAccount(Account account) {
+        if (account == null || account.getStatus() == null) {
+            return false;
+        }
+        return account.getStatus().equals("ACTIVE") && account.getBalance() > 0;
+    }
+
+    /**
+     * Log payment without sensitive data
+     */
+    public void logPayment(String cardNumber, String amount) {
+        String maskedCard = cardNumber != null && cardNumber.length() > 4 
+            ? "****" + cardNumber.substring(cardNumber.length() - 4) 
+            : "****";
+        LOGGER.info(() -> "Processing payment: Card=" + maskedCard + ", Amount=" + amount);
+    }
+
+    // Helper class
+    static class Account {
+        private String status;
+        private double balance;
+
+        public String getStatus() { return status; }
+        public double getBalance() { return balance; }
+    }
+}