Merge pull request #332 from pusher/SubscriptionCountEvent

Add Subscription count event

Author: singhashmeet

CHANGELOG.md

@@ -1,5 +1,8 @@
 # pusher-websocket-java changelog
 
+### Version 2.4.0 - 15th July 2022
+* Add support for Subscription count events
+
 ### Version 2.3.0 - 4th July 2022
 * Added support for user sign in and server to user messages
 * Fixed issue with calling disconnect while the client is attempting reconnection

README.md

@@ -74,7 +74,7 @@ The pusher-java-client is available in Maven Central.
     <dependency>
       <groupId>com.pusher</groupId>
       <artifactId>pusher-java-client</artifactId>
-      <version>2.3.0-beta</version>
+      <version>2.4.0</version>
     </dependency>
 </dependencies>
 ```
@@ -83,7 +83,7 @@ The pusher-java-client is available in Maven Central.
 
 ```groovy
 dependencies {
-  compile 'com.pusher:pusher-java-client:2.3.0-beta'
+  compile 'com.pusher:pusher-java-client:2.4.0'
 }
 ```
 
@@ -256,6 +256,19 @@ Channel channel = pusher.subscribe("my-channel", new ChannelEventListener() {
 
     // Other ChannelEventListener methods
 });
+```
+If you wish to be informed for subscription count events, use the `bind` function to listen to event type `pusher:subscription_count`:
+
+```java
+Channel channel = pusher.subscribe("my-channel");
+channel.bind("pusher:subscription_count", new SubscriptionEventListener() {
+    @Override
+    public void onEvent(PusherEvent event) {
+        System.out.println("Received event with data: " + event.toString());
+        System.out.println("Subscription Count is: " + channel.getCount());
+    }
+});
+
 ```
 
 ### Private channels

build.gradle

@@ -26,7 +26,7 @@ def getProperty = { property ->
 }
 
 group = "com.pusher"
-version = "2.3.0-beta"
+version = "2.4.0"
 sourceCompatibility = "1.8"
 targetCompatibility = "1.8"
 

src/main/java/com/pusher/client/channel/impl/BaseChannel.java

@@ -2,7 +2,6 @@
 
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Set;
 
@@ -11,19 +10,23 @@
 import com.google.gson.GsonBuilder;
 import com.pusher.client.channel.*;
 import com.pusher.client.channel.impl.message.SubscribeMessage;
+import com.pusher.client.channel.impl.message.SubscriptionCountData;
 import com.pusher.client.channel.impl.message.UnsubscribeMessage;
 import com.pusher.client.util.Factory;
 
 public abstract class BaseChannel implements InternalChannel {
     protected final Gson GSON;
     private static final String INTERNAL_EVENT_PREFIX = "pusher_internal:";
     protected static final String SUBSCRIPTION_SUCCESS_EVENT = "pusher_internal:subscription_succeeded";
+    protected static final String SUBSCRIPTION_COUNT_EVENT = "pusher_internal:subscription_count";
+    protected static final String PUBLIC_SUBSCRIPTION_COUNT_EVENT = "pusher:subscription_count";
     private Set<SubscriptionEventListener> globalListeners = new HashSet<SubscriptionEventListener>();
     private final Map<String, Set<SubscriptionEventListener>> eventNameToListenerMap = new HashMap<String, Set<SubscriptionEventListener>>();
     protected volatile ChannelState state = ChannelState.INITIAL;
     private ChannelEventListener eventListener;
     private final Factory factory;
     private final Object lock = new Object();
+    private Integer subscriptionCount;
 
     public BaseChannel(final Factory factory) {
         GsonBuilder gsonBuilder = new GsonBuilder();
@@ -37,6 +40,11 @@ public BaseChannel(final Factory factory) {
     @Override
     abstract public String getName();
 
+    @Override
+    public Integer getCount() {
+        return subscriptionCount;
+    }
+
     @Override
     public void bind(final String eventName, final SubscriptionEventListener listener) {
         validateArguments(eventName, listener);
@@ -112,6 +120,8 @@ public PusherEvent prepareEvent(String event, String message) {
     public void onMessage(String event, String message) {
         if (event.equals(SUBSCRIPTION_SUCCESS_EVENT)) {
             updateState(ChannelState.SUBSCRIBED);
+        }else if (event.equals(SUBSCRIPTION_COUNT_EVENT)) {
+            handleSubscriptionCountEvent(message);
         } else {
             final Set<SubscriptionEventListener> listeners = getInterestedListeners(event);
             if (listeners != null) {
@@ -184,6 +194,12 @@ private void validateArguments(final String eventName, final SubscriptionEventLi
         }
     }
 
+    private void handleSubscriptionCountEvent(final String message) {
+        final SubscriptionCountData subscriptionCountMessage = GSON.fromJson(message, SubscriptionCountData.class);
+        subscriptionCount = subscriptionCountMessage.getCount();
+        onMessage(PUBLIC_SUBSCRIPTION_COUNT_EVENT, message);
+    }
+
     protected Set<SubscriptionEventListener> getInterestedListeners(String event) {
         synchronized (lock) {
             Set<SubscriptionEventListener> listeners = new HashSet<SubscriptionEventListener>();

src/main/java/com/pusher/client/channel/impl/InternalChannel.java

@@ -11,6 +11,8 @@ public interface InternalChannel extends Channel, Comparable<InternalChannel> {
 
     String toUnsubscribeMessage();
 
+    Integer getCount();
+
     PusherEvent prepareEvent(String event, String message);
 
     void onMessage(String event, String message);

src/main/java/com/pusher/client/channel/impl/message/SubscriptionCountData.java

@@ -0,0 +1,12 @@
+package com.pusher.client.channel.impl.message;
+
+import com.google.gson.annotations.SerializedName;
+
+public class SubscriptionCountData {
+    @SerializedName("subscription_count")
+    public Integer count;
+
+    public int getCount(){
+        return count;
+    }
+}