BAEL-1545 - Nats Tutorial (#3904)

2018-03-29 01:06:24 -04:00
parent 5b00f0e0e3
commit 48b8d2c8a5
3 changed files with 273 additions and 0 deletions
@@ -0,0 +1,114 @@
+package com.baeldung.jnats;
+
+import io.nats.client.Message;
+import io.nats.client.SyncSubscription;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+public class NatsClientLiveTest {
+
+    @Test
+    public void givenMessageExchange_MessagesReceived() throws Exception {
+
+        NatsClient client = connectClient();
+
+        SyncSubscription fooSubscription = client.subscribeSync("foo.bar");
+        SyncSubscription barSubscription = client.subscribeSync("bar.foo");
+        client.publishMessage("foo.bar", "bar.foo", "hello there");
+
+        Message message = fooSubscription.nextMessage(200);
+        assertNotNull("No message!", message);
+        assertEquals("hello there", new String(message.getData()));
+
+        client.publishMessage(message.getReplyTo(), message.getSubject(), "hello back");
+
+        message = barSubscription.nextMessage(200);
+        assertNotNull("No message!", message);
+        assertEquals("hello back", new String(message.getData()));
+    }
+
+
+    private NatsClient connectClient() {
+        return new NatsClient();
+    }
+
+    @Test
+    public void whenWildCardSubscription_andMatchTopic_MessageReceived() throws Exception {
+
+        NatsClient client = connectClient();
+
+        SyncSubscription fooSubscription = client.subscribeSync("foo.*");
+
+        client.publishMessage("foo.bar", "bar.foo", "hello there");
+
+        Message message = fooSubscription.nextMessage(200);
+        assertNotNull("No message!", message);
+        assertEquals("hello there", new String(message.getData()));
+    }
+
+    @Test
+    public void whenWildCardSubscription_andNotMatchTopic_NoMessageReceived() throws Exception {
+
+        NatsClient client = connectClient();
+
+        SyncSubscription fooSubscription = client.subscribeSync("foo.*");
+
+        client.publishMessage("foo.bar.plop", "bar.foo", "hello there");
+
+        Message message = fooSubscription.nextMessage(200);
+        assertNull("Got message!", message);
+
+
+        SyncSubscription barSubscription = client.subscribeSync("foo.>");
+
+        client.publishMessage("foo.bar.plop", "bar.foo", "hello there");
+
+        message = barSubscription.nextMessage(200);
+        assertNotNull("No message!", message);
+        assertEquals("hello there", new String(message.getData()));
+
+
+    }
+
+
+    @Test
+    public void givenRequest_ReplyReceived() {
+
+        NatsClient client = connectClient();
+        client.installReply("salary.requests", "denied!");
+
+        Message reply = client.makeRequest("salary.requests", "I need a raise.");
+        assertNotNull("No message!", reply);
+        assertEquals("denied!", new String(reply.getData()));
+
+    }
+
+    @Test
+    public void givenQueueMessage_OnlyOneReceived() throws Exception {
+
+        NatsClient client = connectClient();
+
+        SyncSubscription queue1 = client.joinQueueGroup("foo.bar.requests", "queue1");
+        SyncSubscription queue2 = client.joinQueueGroup("foo.bar.requests", "queue1");
+
+        client.publishMessage("foo.bar.requests", "queuerequestor", "foobar");
+
+        List<Message> messages = new ArrayList<>();
+
+        Message message = queue1.nextMessage(200);
+
+        if (message != null) messages.add(message);
+        message = queue2.nextMessage(200);
+
+        if (message != null) messages.add(message);
+        assertEquals(1, messages.size());
+
+    }
+
+}