update examples (#38)

Author: YangKian

examples/README.md

@@ -2,28 +2,14 @@
 
 ## Prerequisites 
 
-- hstreamdb server [v0.5.2.0](https://hub.docker.com/layers/hstreamdb/hstream/v0.5.2.0/images/sha256-d26234758cd47916d6a5d137a3690cdeeddaf7af041a8eea5e7c1d7ada43f3b8)
-- hstreamdb-java [v0.4.0](https://search.maven.org/artifact/io.hstream/hstreamdb-java/0.4.0/jar) 
+- hstreamdb server [v0.6.0.0](https://hub.docker.com/layers/hstreamdb/hstream/v0.6.0/images/sha256-8502a7e4d609becc1d6f998f59f38a2785f878795a6ed8c81be8b38d0aed3109?context=explore)
+- hstreamdb-java [v0.6.0](https://search.maven.org/artifact/io.hstream/hstreamdb-java/0.6.0/jar) 
 
 ## Examples
 
-- [ConsumerExample.java](app/src/main/java/io/hstream/example/ConsumerExample.java) - How to consume messages from a subscription
-- [StreamQueryExample.java](app/src/main/java/io/hstream/example/StreamQueryExample.java) - How to use SQL commands to query data from streams
+- [CreateStreamExample.java](src/main/java/io/hstream/example/CreateStreamExample.java) - How to create a stream
+- [CreateSubscriptionExample.java](src/main/java/io/hstream/example/CreateSubscriptionExample.java) - How to create a subscription
+- [ProducerExample.java](src/main/java/io/hstream/example/ProducerExample.java) - How to produce messages to a stream
+- [ConsumerExample.java](src/main/java/io/hstream/example/ConsumerExample.java) - How to consume messages from a subscription
+- [StreamQueryExample.java](src/main/java/io/hstream/example/StreamQueryExample.java) - How to use SQL commands to query data from streams
 
-## Run
-
-### Step 1: Start HStreamDB Server
-
-```bash
-
-./start-hstreamdb.sh
-
-```
-
-### Step 2: Run this Example 
-
-```bash
-
-gradle run
-
-```

examples/build.gradle

@@ -10,7 +10,7 @@ repositories {
 }
 
 dependencies {
-    implementation 'io.hstream:hstreamdb-java:0.4.0'
+    implementation 'io.hstream:hstreamdb-java:0.6.0'
 }
 
 application {

examples/src/main/java/io/hstream/example/ConsumerExample.java

@@ -1,43 +1,23 @@
 package io.hstream.example;
 
 import io.hstream.*;
-import java.util.Random;
 
+/** This example shows how to consume data from specified subscription */
 public class ConsumerExample {
   private static final String SERVICE_URL = "localhost:6570";
-  private static final String DEMO_STREAM = "demo_stream";
   private static final String DEMO_SUBSCRIPTION = "demo_stream";
 
   public static void main(String[] args) {
     HStreamClient client = HStreamClient.builder().serviceUrl(SERVICE_URL).build();
 
-    client.createStream(DEMO_STREAM);
-
-    Subscription subscription =
-        new Subscription(
-            DEMO_SUBSCRIPTION,
-            DEMO_STREAM,
-            new SubscriptionOffset(SubscriptionOffset.SpecialOffset.LATEST));
-    client.createSubscription(subscription);
-
-    Producer producer =
-        client.newProducer().stream(DEMO_STREAM).enableBatch().recordCountLimit(1000).build();
-
-    Random random = new Random();
-    byte[] rawRecord = new byte[100];
-    for (int i = 0; i < 1000; ++i) {
-      random.nextBytes(rawRecord);
-      producer.writeAsync(rawRecord);
-    }
-    producer.flush();
-
     Consumer consumer =
         client
             .newConsumer()
             .subscription(DEMO_SUBSCRIPTION)
             .rawRecordReceiver(
                 (receivedRawRecord, responder) -> {
                   System.out.println("get record: " + receivedRawRecord.getRecordId());
+                  responder.ack();
                 })
             .build();
     consumer.startAsync().awaitRunning();

examples/src/main/java/io/hstream/example/CreateStreamExample.java

@@ -0,0 +1,15 @@
+package io.hstream.example;
+
+import io.hstream.HStreamClient;
+
+/** This example shows how to create a stream */
+public class CreateStreamExample {
+  private static final String SERVICE_URL = "localhost:6570";
+  private static final String DEMO_STREAM = "demo_stream";
+
+  public static void main(String[] args) {
+    HStreamClient client = HStreamClient.builder().serviceUrl(SERVICE_URL).build();
+
+    client.createStream(DEMO_STREAM);
+  }
+}

examples/src/main/java/io/hstream/example/CreateSubscriptionExample.java

@@ -0,0 +1,37 @@
+package io.hstream.example;
+
+import io.hstream.*;
+
+/** This example shows how to create a subscription associated to the specified stream */
+public class CreateSubscriptionExample {
+  private static final String SERVICE_URL = "localhost:6570";
+  private static final String DEMO_STREAM = "demo_stream";
+  private static final String DEMO_SUBSCRIPTION = "demo_subscription";
+
+  public static void main(String[] args) {
+    HStreamClient client = HStreamClient.builder().serviceUrl(SERVICE_URL).build();
+    // create a subscription which consume data from the tail of the stream.
+    Subscription subscriptionFromEarlist =
+        Subscription.newBuilder().subscription(DEMO_SUBSCRIPTION).stream(DEMO_STREAM)
+            .offset(new SubscriptionOffset(SubscriptionOffset.SpecialOffset.EARLIEST))
+            .ackTimeoutSeconds(600)
+            .build();
+    client.createSubscription(subscriptionFromEarlist);
+
+    // create a subscription which consume data from the tail of the stream.
+    Subscription subscriptionFromLatest =
+        Subscription.newBuilder().subscription(DEMO_SUBSCRIPTION).stream(DEMO_STREAM)
+            .offset(new SubscriptionOffset(SubscriptionOffset.SpecialOffset.LATEST))
+            .ackTimeoutSeconds(600)
+            .build();
+    client.createSubscription(subscriptionFromLatest);
+
+    // create a subscription which consume data from specified RecordId.
+    Subscription subscription =
+        Subscription.newBuilder().subscription(DEMO_SUBSCRIPTION).stream(DEMO_STREAM)
+            .offset(new SubscriptionOffset(new RecordId(1, 2)))
+            .ackTimeoutSeconds(600)
+            .build();
+    client.createSubscription(subscription);
+  }
+}

examples/src/main/java/io/hstream/example/ProducerExample.java

@@ -0,0 +1,25 @@
+package io.hstream.example;
+
+import io.hstream.*;
+import java.util.Random;
+import java.util.concurrent.CompletableFuture;
+
+/** This example shows how to write data to an existed stream */
+public class ProducerExample {
+  private static final String SERVICE_URL = "localhost:6570";
+  private static final String DEMO_STREAM = "demo_stream";
+
+  public static void main(String[] args) {
+    HStreamClient client = HStreamClient.builder().serviceUrl(SERVICE_URL).build();
+
+    Producer producer =
+        client.newProducer().stream(DEMO_STREAM).enableBatch().recordCountLimit(1000).build();
+
+    Random random = new Random();
+    byte[] rawRecord = new byte[100];
+    for (int i = 0; i < 1000; ++i) {
+      random.nextBytes(rawRecord);
+      CompletableFuture<RecordId> future = producer.write(rawRecord);
+    }
+  }
+}