Added cassandra Migration code

v2/spanner-to-sourcedb/pom.xml

@@ -89,6 +89,18 @@
             <version>${project.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.datastax.oss</groupId>
+            <artifactId>java-driver-core</artifactId>
+            <version>4.16.0</version>
+            <scope>compile</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.11</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
 </project>

v2/spanner-to-sourcedb/src/main/java/com/google/cloud/teleport/v2/templates/utils/CassandraConnection.java

@@ -0,0 +1,45 @@
+package com.google.cloud.teleport.v2.templates.utils;
+import com.datastax.oss.driver.api.core.CqlSession;
+import com.datastax.oss.driver.api.core.auth.ProgrammaticPlainTextAuthProvider;
+
+import java.net.InetSocketAddress;
+
+public class CassandraConnection {
+    private static CassandraConnection instance;
+    private CqlSession session;
+
+    // Private constructor to enforce Singleton
+    private CassandraConnection(String host, int port, String datacenter, String username, String password) {
+        try {
+            session = CqlSession.builder()
+                    .addContactPoint(new InetSocketAddress(host, port))
+                    .withLocalDatacenter(datacenter)
+                   // .withAuthProvider(new ProgrammaticPlainTextAuthProvider(username, password)) // Use if authentication is enabled
+                    .build();
+            session.execute("USE mykeyspace;");
+
+            System.out.println("Connected to Cassandra!");
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to connect to Cassandra", e);
+        }
+    }
+    public static synchronized CassandraConnection getInstance(String host, int port, String datacenter, String username, String password) {
+        if (instance == null) {
+            instance = new CassandraConnection(host, port, datacenter, username, password);
+        }
+        return instance;
+    }
+
+    // Method to get the CqlSession
+    public CqlSession getSession() {
+        return session;
+    }
+
+    // Close the session when done
+    public void close() {
+        if (session != null) {
+            session.close();
+            System.out.println("Cassandra connection closed.");
+        }
+    }
+}

v2/spanner-to-sourcedb/src/main/java/com/google/cloud/teleport/v2/templates/utils/CassandraDao.java

@@ -0,0 +1,44 @@
+package com.google.cloud.teleport.v2.templates.utils;
+
+import java.io.Serializable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import com.datastax.oss.driver.api.core.CqlSession;
+/** Writes data to MySQL. */
+public class CassandraDao implements Serializable {
+    private static final Logger LOG = LoggerFactory.getLogger(CassandraDao.class);
+    String cassandraHost;
+    String cassandraUser;
+    String cassandraPasswd;
+    int port;
+    String datacenter;
+
+    public CassandraDao(String cassandraHost, int cassandraPort, String dataCenter, String cassandraUser, String cassandraPasswd) {
+        this.cassandraHost = cassandraHost;
+        this.port = cassandraPort;
+        this.cassandraUser = cassandraUser;
+        this.cassandraPasswd = cassandraPasswd;
+        this.datacenter = dataCenter;
+    }
+
+    // writes to database
+    public void write(String cassandraStatement) {
+        CassandraConnection cassandraConnection = null;
+        CqlSession session = null;
+
+        try {
+            cassandraConnection = CassandraConnection.getInstance(this.cassandraHost , this.port, this.datacenter, this.cassandraUser,this.cassandraPasswd);
+            session = cassandraConnection.getSession();
+            session.execute(cassandraStatement);
+        } catch (Exception e) {
+            System.err.println("An error occurred while interacting with Cassandra:");
+            e.printStackTrace();
+        } finally {
+            // Ensure the connection is closed in the finally block
+            if (cassandraConnection != null) {
+                cassandraConnection.close();
+            }
+        }
+    }
+}
+