Speaker: Tim Berglund, Global Director of Training at DataStax So you’re a JVM developer, you understand Cassandra’s architecture, and you’re on your way to knowing its data model well enough to build descriptive data models that perform well. What you need now is to know the Java Driver. What seems like an inconsequential library that proxies your application’s queries to your Cassandra cluster is actually a sophisticated piece of code that solves a lot of problems for you that early Cassandra developers had to code by hand. Come to this session to see features you might be missing and examples of how to use the Java driver in real applications.

1. Building
Java Applica)ons
with
Cassandra
"VNDGTINWPF

2. 2000
4000
6000
8000
E000
C000
A000
0000
Client Machine
Load Balancer

3. tim name:
Tim
role:
teacher
kristen
name:
Kristen
role:
marketing
billy role:
CEO
matt name:
Matt
role:
founder
status:
active
status:
chill

4. https://github.com/datastax/java-­‐driver

5. DataStax
Java
Driver
• Open
source
(ASL
2.0)
• Where
CQL
happens
• Ac9vely
developed
• Now
faster
than
ThriD
• Doesn’t
make
you
want
to
die

6. Every Use Case
has a Story

7. Your
Story:
ň/C[DG6JTKHVKUPQVVJGEQQNGUVʼn

8. Gradle Build
apply plugin: 'java'
repositories {
jcenter()
}
dependencies {
compile 'com.datastax.cassandra:cassandra-driver-core:2.1.2'
testCompile 'org.testng:testng:6.8.8'
testCompile 'junit:junit:4.11'
}

9. Cluster Interface
Cluster cluster = Cluster.builder()
.addContactPoints(“192.168.50.1”)
.build();
Session session = cluster.connect(“IoT_keyspace);
session.execute(
INSERT INTO sensor
(sensor_id, reading, time)
VALUES
(24601, 2.171828, now())”);

10. Your
Story:
ň+LWUVYCPVVQFQCSWGT[ʼn

11. BasicQueries
ResultSet resultSet = session.execute(SELECT * FROM sensor);
ListRow rows = resultSet.all();
for(Row row : rows) {
String sensorId = row.getString(sensor_id );
double reading = row.getDouble(reading );
Date time = row.getDate(time );
}

12. Prepared Statements
PreparedStatement insertReading =
session.prepare(
INSERT INTO sensor
(sensor_id, reading, time) VALUES (?, ?, ?)”
);
Statement statement = insertReading
.bind(24601, 2.71828, new Date())
.setConsistencyLevel(ConsistencyLevel.QUORUM);
session.execute(statement);

13. Your
Story:
ň+YCPVNQCFDCNCPEKPIʼn

14. 2000
4000
6000
8000
E000
C000
A000
0000
Client Machine

15. Cluster Interface
Cluster cluster = Cluster.builder()
.addContactPoints(“192.168.50.1”)
.build();

16. Cluster Interface
Cluster cluster = Cluster.builder()
.addContactPoints(“192.168.50.1”,
“192.168.50.4”,
“192.168.50.8”)
.build();

17. Your
Story:
ň+ņNNLWUVQRVKOKGEQQTFKPCVQT
NQCFVJGPʼn

18. 2000
4000
6000
8000
E000
C000
A000
0000
Client Machine

19. 2000
4000
6000
8000
E000
C000
A000
0000
Client Machine
1.2ms
2.9ms
15.3ms

20. Outsmar(ng
Yourself
• Pick
one
node
• Send
all
coordina9on
traffic
to
that
node
• Hey,
maybe
make
it
a
fat
node!
• WhiteListPolicy

21. WhiteListing
ListInetSocketAddress whiteList = new
ArrayListInetSocketAddress();
whiteList.add(...);
Cluster c = Cluster.builder().withLoadBalancingPolicy(
new WhiteListPolicy(
new RoundRobinPolicy(),
whiteList)).build();

22. Your
Story:
ň+OKUU,2#ʼn
[QWJCXGKUUWGU

23. Mapper Object
apply plugin: 'java'
repositories {
jcenter()
}
dependencies {
compile 'com.datastax.cassandra:cassandra-driver-core:2.1.2'
compile 'com.datastax.cassandra:cassandra-driver-mapping:2.1.2'
testCompile 'org.testng:testng:6.8.8'
testCompile 'junit:junit:4.11'
}

24. CREATE TABLE sensor (
sensor_id int,
reading double,
time timestamp
);
Mapper Object
@UDT(keyspace = IoT_keyspace, name = sensor)
public class Sensor {
private int sensorId;
private double reading;
private Date Time;
// getters and setters elided with extreme prejudice...
}

25. Mapper Object
MappingManager manager = new MappingManager(session);
Mapper mapper = manager.mapper(Sensor.class);
Sensor reading = mapper.get(24601);

26. Your
Story:
ň+NKMGUNQYSWGTKGUʼn

27. FutureResults
ResultSetFuture future =
session.executeAsync(SELECT * FROM sensor);
// Returns immediately
// Go do productive things here…
// Then finally block on the results when you must
ResultSet futureResults = future.get();
ListRow rows = resultSet.all();

28. FutureResults
Executor executor = Executors.newCachedThreadPool();
ResultSetFuture future =
session.executeAsync(SELECT * FROM sensor);
future.addListener(new Runnable() {
public void run() {
// Do the things here…
}
}, executor);

29. Your
Story:
ň6TCPUOKVYKPFQYUJCXGDGGPC
VJKPINQPIGTVJCPOQUVFGXGNQRGTU
JCXGDGGPCNKXGʼn

31. Thank
You!
VNDGTINWPF