Java 5 example code snippets

Below you will find an assortment of small code examples which show you how to do various things with the Java 5 API. Most of the snippets are written in a way that they would be compilable as one program and as such concepts already demonstrated are not repeated in subsequent snippets.

The following datatype is used for these code snipplets:

module Test
{
   struct Foo
   {
      long userID;    // User ID
      string message; // message
   };
   #pragma keylist Foo userID
};

Using the DataWriter

Creating a DataWriter with default QoS

import Test.Foo;
System.setProperty(ServiceEnvironment.IMPLEMENTATION_CLASS_NAME_PROPERTY,"org.opensplice.dds.core.OsplServiceEnvironment");
ServiceEnvironment env = ServiceEnvironment.createInstance(SnippetClassName.class.getClassLoader());
DomainParticipantFactory dpf = DomainParticipantFactory.getInstance(env);
DomainParticipant p = dpf.createParticipant();
Topic<Foo> topic = p.createTopic("TypeTopic", Foo.class);
Publisher publisher = p.createPublisher()
DataWriter<Foo> writer = publisher.createDataWriter(topic)

Creating a DataWriter with your own QoS

Reliability r = PolicyFactory.getPolicyFactory(env).Reliability().withReliable();
Durability d = PolicyFactory.getPolicyFactory(env).Durability().withTransient();
DataWriter<Foo> writer = publisher.createDataWriter(topic, publisher.getDefaultDataWriterQos().withPolicies(r, d));

Getting and setting DataWriter QoS

DataWriterQos dwq = writer.getQos();
Duration deadline = Duration.newDuration(5, TimeUnit.SECONDS, env);
dwq = dwq.withPolicy(dwq.getDeadline().withPeriod(deadline));
writer.setQos(dwq);

Writing a sample

Foo foo = new Foo(1, "Hello World");
writer.write(foo);

Writing with timestamps

Time t = Time.newTime(5, TimeUnit.SECONDS, env);
writer.write(foo, t);

Register an instance handle and a write sample using it

InstanceHandle ih = dataWriter.registerInstance(foo);
writer.write(foo, ih);

Using the DataReader

Creating a DataReader with the default QoS

Subscriber subscriber = p.createSubscriber()
DataReader<Foo> reader = subscriber.createDataReader(topic)

Creating a DataReader with your own QoS

Reliability r = PolicyFactory.getPolicyFactory(env).Reliability().withReliable();
Durability d = PolicyFactory.getPolicyFactory(env).Durability().withTransient();
DataReader<Foo> reader = subscriber.createDataReader(topic, subscriber.getDefaultDataReaderQos().withPolicies(r, d));

Reading a sample

Iterator<Sample<Foo>> messages = reader.read();

Reading samples into your own container

List<Sample<Foo>> samples = new ArrayList<Sample<Foo>>(10);
List<Sample<Msg>> result = reader.read(samples);

Reading with a InstanceHandle (lookup key from sample)

Selector<Foo> selector = reader.select();
selector.instance(reader.lookupInstance(foo));
List<Sample<Foo>> result = dataReader.read(samples, selector);

Reading samples with the Selector

DataState ds = subscriber.createDataState().withAnyInstanceState().withAnySampleState().withAnyViewState();
Selector<Foo> selector = reader.select().dataState(ds);
List<Sample<Foo>> result = dataReader.read(samples, selector);

Accessing the samples

while (result.hasNext()) {
    Foo foo = result.next().getData();
    System.out.println("Id: " + foo.UserID + " Message: " + foo.message);
}