Simplification of Builder Use (#897)

Added `of()` static functions to MQTT5 packet types to allow simplified creation with basic arguments.

Author: sbSteveK

src/main/java/software/amazon/awssdk/crt/mqtt5/packets/PublishPacket.java

@@ -11,6 +11,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.util.Objects;
 
 /**
  * Data model of an <a href="https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901100">MQTT5 PUBLISH</a> packet
@@ -181,6 +182,32 @@ public List<Long> getSubscriptionIdentifiers() {
         return this.subscriptionIdentifiers;
     }
 
+    /**
+     * Creates a {@link PublishPacket} containing only the most common fields:
+     * <em>topic</em>, <em>QoS</em>, and <em>payload</em>.
+     * <p>
+     * Internally this is just syntactic sugar around
+     * {@link PublishPacketBuilder#PublishPacketBuilder(String, QOS, byte[])}
+     * followed by {@link PublishPacketBuilder#build()}.
+     * All optional MQTT 5 properties (retain flag, user properties, etc.)
+     * are left {@code null} / unset.
+     *
+     * @param topic   The topic this message should be published to.
+     * @param qos     The MQTT quality of service level the message should be delivered with.
+     * @param payload The payload for the publish message.
+     * @return an immutable {@code PublishPacket} ready for use
+     *
+     * @throws NullPointerException if {@code topic}, {@code qos}, or
+     *                              {@code payload} is {@code null}
+     */
+    public static PublishPacket of(String topic, QOS qos, byte[] payload) {
+        Objects.requireNonNull(topic, "topic");
+        Objects.requireNonNull(qos, "qos");
+        Objects.requireNonNull(payload, "payload");
+
+        return new PublishPacketBuilder(topic, qos, payload).build();
+    }
+
     /**
      * Creates a Mqtt5Client options instance
      * @throws CrtRuntimeException If the system is unable to allocate space for a native MQTT client structure

src/main/java/software/amazon/awssdk/crt/mqtt5/packets/SubscribePacket.java

@@ -10,6 +10,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.util.Objects;
 
 import software.amazon.awssdk.crt.mqtt5.QOS;
 
@@ -28,6 +29,27 @@ private SubscribePacket(SubscribePacketBuilder builder) {
         this.userProperties = builder.userProperties;
     }
 
+    /**
+     * Creates a {@link SubscribePacket} containing only a single subscription topic and qos:
+     * <em>topicFilter</em>, <em>QoS</em>.
+     * <p>
+     * Internally this is just syntactic sugar around
+     * {@link SubscribePacketBuilder#SubscribePacketBuilder(String, QOS)}
+     * followed by {@link SubscribePacketBuilder#build()}.
+     * 
+     * @param topicFilter The topic filter to subscribe to.
+     * @param qos The maximum QoS on which the subscriber will accept publish messages.
+     * @return an immutable {@code SubscribePacket} ready for use
+     * 
+     * @throws NullPointerException if {@code topicFilter} or {@code qos} is {@code null}
+     */
+    public static SubscribePacket of(String topicFilter, QOS qos) {
+        Objects.requireNonNull(topicFilter, "topicFilter");
+        Objects.requireNonNull(qos, "qos");
+
+        return new SubscribePacketBuilder(topicFilter, qos).build();
+    }
+
     /**
      * Returns the list of subscriptions that the client wishes to listen to
      *

src/main/java/software/amazon/awssdk/crt/mqtt5/packets/UnsubscribePacket.java

@@ -6,6 +6,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Data model of an <a href="https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc384800445">MQTT5 UNSUBSCRIBE</a> packet.
@@ -20,6 +21,25 @@ private UnsubscribePacket(UnsubscribePacketBuilder builder) {
         this.subscriptions = builder.subscriptions;
     }
 
+    /**
+     * Creates an {@link UnsubscribePacket} containing only a single subscription topic to unsubscribe from:
+     * <em>topicFilter</em>.
+     * <p>
+     * Internally this is just syntactic sugar around
+     * {@link UnsubscribePacketBuilder#UnsubscribePacketBuilder(String)}
+     * followed by {@link UnsubscribePacketBuilder#build()}.
+     * 
+     * @param topicFilter The topic filter to unsubscribe from.
+     * @return an immutable {@code UnsubscribePacket} ready for use
+     * 
+     * @throws NullPointerException if {@code topicFilter} is {@code null}
+     */
+    public static UnsubscribePacket of(String topicFilter) {
+        Objects.requireNonNull(topicFilter, "topicFilter");
+
+        return new UnsubscribePacketBuilder(topicFilter).build();
+    }
+
     /**
      * Returns a list of subscriptions that the client wishes to unsubscribe from.
      *

src/test/java/software/amazon/awssdk/crt/test/Mqtt5ClientTest.java

@@ -2101,6 +2101,68 @@ public void Op_SharedSubscription() throws Exception {
         CrtResource.waitForNoResources();
     }
 
+    public void doOp_DirectPacketBuilders() {
+        String testUUID = UUID.randomUUID().toString();
+        String testTopic = "test/MQTT5_Binding_Java_" + testUUID;
+        try {
+            Mqtt5ClientOptionsBuilder builder = new Mqtt5ClientOptionsBuilder(AWS_TEST_MQTT5_IOT_CORE_HOST, 8883l);
+            LifecycleEvents_Futured events = new LifecycleEvents_Futured();
+            builder.withLifecycleEvents(events);
+
+            TlsContextOptions tlsOptions = TlsContextOptions.createWithMtlsFromPath(
+                AWS_TEST_MQTT5_IOT_CORE_RSA_CERT, AWS_TEST_MQTT5_IOT_CORE_RSA_KEY);
+            TlsContext tlsContext = new TlsContext(tlsOptions);
+            tlsOptions.close();
+            builder.withTlsContext(tlsContext);
+
+            PublishEvents_Futured publishEvents = new PublishEvents_Futured();
+            builder.withPublishEvents(publishEvents);
+
+            PublishPacket publishPacket = PublishPacket.of(testTopic, QOS.AT_LEAST_ONCE, "Hello World".getBytes());
+            SubscribePacket subscribePacket = SubscribePacket.of(testTopic, QOS.AT_LEAST_ONCE);
+            UnsubscribePacket unsubscribePacket = UnsubscribePacket.of(testTopic);
+
+            try (Mqtt5Client client = new Mqtt5Client(builder.build())) {
+                client.start();
+                events.connectedFuture.get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+
+                client.subscribe(subscribePacket).get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+
+                client.publish(publishPacket).get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+                publishEvents.publishReceivedFuture.get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+
+                publishEvents.publishReceivedFuture = new CompletableFuture<>();
+                publishEvents.publishPacket = null;
+                client.unsubscribe(unsubscribePacket).get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+                client.publish(publishPacket).get(OPERATION_TIMEOUT_TIME, TimeUnit.SECONDS);
+
+                assertEquals(
+                    "Publish after unsubscribe still arrived!",
+                    publishEvents.publishPacket,
+                    null);
+
+                client.stop();
+            }
+
+            if (tlsContext != null) {
+                tlsContext.close();
+            }
+
+        } catch (Exception ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+
+    @Test
+    public void Op_DirectPacketBuilders()  throws Exception {
+        skipIfNetworkUnavailable();
+        Assume.assumeNotNull(AWS_TEST_MQTT5_IOT_CORE_HOST, AWS_TEST_MQTT5_IOT_CORE_RSA_CERT, AWS_TEST_MQTT5_IOT_CORE_RSA_KEY);
+    
+        TestUtils.doRetryableTest(this::doOp_DirectPacketBuilders, TestUtils::isRetryableTimeout, MAX_TEST_RETRIES, TEST_RETRY_SLEEP_MILLIS);
+
+        CrtResource.waitForNoResources();
+    }
+
     /**
      * ============================================================
      * Error Operation Tests