WIP: liveobjects experemental implementation

Author: ttypic

android/src/main/java/io/ably/lib/realtime/Channel.java

@@ -3,6 +3,8 @@
 import io.ably.lib.types.AblyException;
 import io.ably.lib.types.ChannelOptions;
 import io.ably.lib.push.PushChannel;
+import io.ably.lib.objects.LiveObjectsPlugin;
+
 
 public class Channel extends ChannelBase {
     /**
@@ -12,8 +14,8 @@ public class Channel extends ChannelBase {
      */
     public final PushChannel push;
 
-    Channel(AblyRealtime ably, String name, ChannelOptions options) throws AblyException {
-        super(ably, name, options);
+    Channel(AblyRealtime ably, String name, ChannelOptions options, LiveObjectsPlugin liveObjectsPlugin) throws AblyException {
+        super(ably, name, options, liveObjectsPlugin);
         this.push = ((io.ably.lib.rest.AblyRest) ably).channels.get(name, options).push;
     }
 

java/src/main/java/io/ably/lib/realtime/Channel.java

@@ -1,11 +1,12 @@
 package io.ably.lib.realtime;
 
+import io.ably.lib.objects.LiveObjectsPlugin;
 import io.ably.lib.types.AblyException;
 import io.ably.lib.types.ChannelOptions;
 
 public class Channel extends ChannelBase {
-    Channel(AblyRealtime ably, String name, ChannelOptions options) throws AblyException {
-        super(ably, name, options);
+    Channel(AblyRealtime ably, String name, ChannelOptions options, LiveObjectsPlugin liveObjectsPlugin) throws AblyException {
+        super(ably, name, options, liveObjectsPlugin);
     }
 
     public interface MessageListener extends ChannelBase.MessageListener {}

lib/src/main/java/io/ably/lib/objects/LiveObjects.java

@@ -0,0 +1,8 @@
+package io.ably.lib.objects;
+
+import io.ably.lib.types.Callback;
+
+public interface LiveObjects {
+    Long getRoot();
+    void getRootAsync(Callback<Long> callback);
+}

lib/src/main/java/io/ably/lib/objects/LiveObjectsPlugin.java

@@ -0,0 +1,5 @@
+package io.ably.lib.objects;
+
+public interface LiveObjectsPlugin {
+    LiveObjects getInstance(String channelName);
+}

lib/src/main/java/io/ably/lib/realtime/AblyRealtime.java

@@ -1,10 +1,14 @@
 package io.ably.lib.realtime;
 
+import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import io.ably.lib.network.HttpEngineFactory;
+import io.ably.lib.objects.LiveObjects;
+import io.ably.lib.objects.LiveObjectsPlugin;
 import io.ably.lib.rest.AblyRest;
 import io.ably.lib.rest.Auth;
 import io.ably.lib.transport.ConnectionManager;
@@ -40,6 +44,13 @@ public class AblyRealtime extends AblyRest {
      */
     public final Channels channels;
 
+    /**
+     * A nullable reference to the LiveObjects plugin.
+     * <p>
+     * This field is initialized only if the LiveObjects plugin is present in the classpath.
+     */
+    private final LiveObjectsPlugin liveObjectsPlugin;
+
     /**
      * Constructs a Realtime client object using an Ably API key or token string.
      * <p>
@@ -72,6 +83,8 @@ public AblyRealtime(ClientOptions options) throws AblyException {
             }
         }
 
+        liveObjectsPlugin = tryInitializeLiveObjectsPlugin();
+
         if(options.autoConnect) connection.connect();
     }
 
@@ -168,6 +181,16 @@ public interface Channels extends ReadOnlyMap<String, Channel> {
         void release(String channelName);
     }
 
+    private LiveObjectsPlugin tryInitializeLiveObjectsPlugin() {
+        try {
+            Class<?> liveObjectsImplementation = Class.forName("io.ably.lib.objects.DefaultLiveObjectsPlugin");
+            return (LiveObjectsPlugin) liveObjectsImplementation.getDeclaredConstructor().newInstance();
+        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | NoSuchMethodException |
+                 InvocationTargetException e) {
+            return null;
+        }
+    }
+
     private class InternalChannels extends InternalMap<String, Channel> implements Channels, ConnectionManager.Channels {
         /**
          * Get the named channel; if it does not already exist,
@@ -187,7 +210,7 @@ public Channel get(final String channelName, final ChannelOptions channelOptions
             // We're not using computeIfAbsent because that requires Java 1.8.
             // Hence there's the slight inefficiency of creating newChannel when it may not be
             // needed because there is an existingChannel.
-            final Channel newChannel = new Channel(AblyRealtime.this, channelName, channelOptions);
+            final Channel newChannel = new Channel(AblyRealtime.this, channelName, channelOptions, liveObjectsPlugin);
             final Channel existingChannel = map.putIfAbsent(channelName, newChannel);
 
             if (existingChannel != null) {

lib/src/main/java/io/ably/lib/realtime/ChannelBase.java

@@ -13,6 +13,8 @@
 import io.ably.lib.http.Http;
 import io.ably.lib.http.HttpCore;
 import io.ably.lib.http.HttpUtils;
+import io.ably.lib.objects.LiveObjects;
+import io.ably.lib.objects.LiveObjectsPlugin;
 import io.ably.lib.transport.ConnectionManager;
 import io.ably.lib.transport.ConnectionManager.QueuedMessage;
 import io.ably.lib.transport.Defaults;
@@ -91,6 +93,23 @@ public abstract class ChannelBase extends EventEmitter<ChannelEvent, ChannelStat
      */
     private boolean released = false;
 
+    private final LiveObjectsPlugin liveObjectsPlugin;
+    private LiveObjects objects;
+
+    public LiveObjects getObjects() throws AblyException {
+        if (liveObjectsPlugin == null) {
+            throw AblyException.fromErrorInfo(
+                new ErrorInfo("LiveObjects plugin hasn't been installed, add runtimeOnly('io.ably:live-objects:<ably-version>') to your dependency tree", 400, 40000)
+            );
+        }
+
+        if (objects == null) {
+            objects = liveObjectsPlugin.getInstance(name);
+        }
+
+        return objects;
+    }
+
     /***
      * internal
      *
@@ -1285,7 +1304,7 @@ else if(stateChange.current.equals(failureState)) {
         }
     }
 
-    ChannelBase(AblyRealtime ably, String name, ChannelOptions options) throws AblyException {
+    ChannelBase(AblyRealtime ably, String name, ChannelOptions options, LiveObjectsPlugin liveObjectsPlugin) throws AblyException {
         Log.v(TAG, "RealtimeChannel(); channel = " + name);
         this.ably = ably;
         this.name = name;
@@ -1295,6 +1314,7 @@ else if(stateChange.current.equals(failureState)) {
         this.attachResume = false;
         state = ChannelState.initialized;
         this.decodingContext = new DecodingContext();
+        this.liveObjectsPlugin = liveObjectsPlugin;
     }
 
     void onChannelMessage(ProtocolMessage msg) {

live-objects/build.gradle.kts

@@ -0,0 +1,21 @@
+plugins {
+    `java-library`
+    alias(libs.plugins.kotlin.jvm)
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(project(":java"))
+    testImplementation(kotlin("test"))
+}
+
+tasks.test {
+    useJUnitPlatform()
+}
+
+kotlin {
+    explicitApi()
+}

live-objects/gradle.properties

@@ -0,0 +1,4 @@
+POM_ARTIFACT_ID=live-objects
+POM_NAME=Live Objects plugin for Ably Pub/Sub SDK
+POM_DESCRIPTION=Live Objects plugin for Ably Pub/Sub SDK
+POM_PACKAGING=jar

live-objects/src/main/kotlin/io/ably/lib/objects/DefaultLiveObjects.kt

@@ -0,0 +1,12 @@
+package io.ably.lib.objects
+
+import io.ably.lib.types.Callback
+
+internal class DefaultLiveObjects(private val channelName: String): LiveObjects {
+
+  override fun getRoot(): Long = channelName.length.toLong()
+
+  override fun getRootAsync(callback: Callback<Long>) {
+    callback.onSuccess(channelName.length.toLong())
+  }
+}

live-objects/src/main/kotlin/io/ably/lib/objects/DefaultLiveObjectsPlugin.kt

@@ -0,0 +1,8 @@
+package io.ably.lib.objects
+
+public class DefaultLiveObjectsPlugin(): LiveObjectsPlugin {
+  override fun greetings(): String = "Hello from Live Objects module"
+
+  override fun getInstance(channelName: String): LiveObjects = DefaultLiveObjects(channelName)
+
+}