Getting Started with Apache Cassandra and Java Part II

GettingStartedTwo.java

import com.datastax.driver.core.*;

public class GettingStartedTwo {

	public static void main(String[] args) {

		Cluster cluster;
		Session session;
		ResultSet results;
		Row rows;

		// Connect to the cluster and keyspace "demo"
		cluster = Cluster
				.builder()
				.addContactPoint("localhost")
				.withRetryPolicy(DefaultRetryPolicy.INSTANCE)
				.withLoadBalancingPolicy(
						new TokenAwarePolicy(new DCAwareRoundRobinPolicy()))
				.build();
		session = cluster.connect("demo");

		// Insert one record into the users table
		PreparedStatement statement = session.prepare(

		"INSERT INTO users" + "(lastname, age, city, email, firstname)"
				+ "VALUES (?,?,?,?,?);");

		BoundStatement boundStatement = new BoundStatement(statement);

		session.execute(boundStatement.bind("Jones", 35, "Austin",
				"[email protected]", "Bob"));

		// Use select to get the user we just entered
		Statement select = QueryBuilder.select().all().from("demo", "users")
				.where(eq("lastname", "Jones"));
		results = session.execute(select);
		for (Row row : results) {
			System.out.format("%s %d \n", row.getString("firstname"),
					row.getInt("age"));
		}

		// Update the same user with a new age
		Statement update = QueryBuilder.update("demo", "users")
				.with(QueryBuilder.set("age", 36))
				.where((QueryBuilder.eq("lastname", "Jones")));
		session.execute(update);
		
		// Select and show the change
		select = QueryBuilder.select().all().from("demo", "users")
				.where(eq("lastname", "Jones"));
		results = session.execute(select);
		for (Row row : results) {
			System.out.format("%s %d \n", row.getString("firstname"),
					row.getInt("age"));
		}

		// Delete the user from the users table
		Statement delete = QueryBuilder.delete().from("users")
				.where(QueryBuilder.eq("lastname", "Jones"));
		results = session.execute(delete);


		// Show that the user is gone
                select = QueryBuilder.select().all().from("demo", "users");
		results = session.execute(select);
		for (Row row : results) {
			System.out.format("%s %d %s %s %s\n", row.getString("lastname"),
					row.getInt("age"), row.getString("city"),
					row.getString("email"), row.getString("firstname"));
		}

		// Clean up the connection by closing it
		cluster.close();
	}
}

Hi, this is Vito, just 4 reminding, there's a word missing @ line 35, "...(eq(..." should be "...(QueryBuilder.eq(...", cus' I confronted with a compile error while I was learning your code. :P

And also @ line 50.

@vitoyuan thanks for the update.

Can you share the code to handle connection pooling. Does Cassandra automatically increases the number of connections when there is a load.

line #10 => Row rows; is not used.

Could you tell what is the Cassandra Driver that you have tested this against and if this is tested on Apache cassandra or DSE?
I was trying to work with Cassandra Java driver 3.0 and DataStax Distritribution for Apache Cassandra 3.3, and I was getting an runtime error : Type class com.datastax.driver.core.DataType$NativeType is not supported

I am getting compilation errors at line 18(DCAwareRoundRobinPolicy: ), 34(QueryBuilder.select), 43(QueryBuilder.update), 58(QueryBuilder.delete) and 64(QueryBuilder.select). Could anyone please help me out?

line 18 error: should use the builder method:

new TokenAwarePolicy(DCAwareRoundRobinPolicy.builder().build()))

This is a workaround think should use the init method first.