Merge pull request #6423 from ZappoMan/messaging

add an example of an entityScript that subscribes to messages

examples/entityScripts/messagesReceiverEntityExample.js

@@ -0,0 +1,56 @@
+//
+//  messagesReceiverEntityExample.js
+//  examples/entityScripts
+//
+//  Created by Brad Hefta-Gaub on 11/18/15.
+//  Copyright 2015 High Fidelity, Inc.
+//
+//  This is an example of an entity script which when assigned to an entity, will detect when the entity is being grabbed by the hydraGrab script
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+(function () {
+
+    var _this;
+
+    var messageReceived = function (channel, message, senderID) {
+        print("message received on channel:" + channel + ", message:" + message + ", senderID:" + senderID);
+    };
+
+    // this is the "constructor" for the entity as a JS object we don't do much here, but we do want to remember
+    // our this object, so we can access it in cases where we're called without a this (like in the case of various global signals)
+    MessagesReceiver = function () {
+        _this = this;
+    };
+
+    MessagesReceiver.prototype = {
+
+        // preload() will be called when the entity has become visible (or known) to the interface
+        // it gives us a chance to set our local JavaScript object up. In this case it means:
+        //   * remembering our entityID, so we can access it in cases where we're called without an entityID
+        //   * unsubscribing from messages
+        //   * connectingf to the messageReceived signal
+        preload: function (entityID) {
+            this.entityID = entityID;
+
+            print("---- subscribing ----");
+            Messages.subscribe("example");
+            Messages.messageReceived.connect(messageReceived);
+        },
+
+        // unload() will be called when the entity has become no longer known to the interface
+        // it gives us a chance to clean up our local JavaScript object. In this case it means:
+        //   * unsubscribing from messages
+        //   * disconnecting from the messageReceived signal
+        unload: function (entityID) {
+            print("---- unsubscribing ----");
+            Messages.unsubscribe("example");
+            Messages.messageReceived.disconnect(messageReceived);
+        },
+    };
+
+    // entity scripts always need to return a newly constructed object of our type
+    return new MessagesReceiver();
+})