Added ShouldUpdate and Update to Services

Author: jeffreylanters

Diff for: Runtime/Controller.cs

@@ -82,6 +82,14 @@ void Update () {
         }
         system.OnUpdate ();
       }
+      // Invoking update method on each service.
+      for (var serviceIndex = 0; serviceIndex < services.Count; serviceIndex++) {
+        var service = services[serviceIndex];
+        if (!service.ShouldUpdate ()) {
+          continue;
+        }
+        service.OnUpdate ();
+      }
     }
 
 #if ECS_PHYSICS || ECS_ALL

Diff for: Runtime/Interfaces/IService.cs

@@ -13,6 +13,17 @@ public interface IService {
     /// </summary>
     void OnInitialized ();
 
+    /// <summary>
+    /// Method invoked when the service updates, will be called every frame.
+    /// </summary>
+    void OnUpdate () { }
+
+    /// <summary>
+    // Method invoked before the system will update, return whether this system
+    // should update. will be called every frame.
+    /// </summary>
+    bool ShouldUpdate ();
+
     /// <summary>
     // Method invoked when the service is drawing the gizmos, will be called
     // every gizmos draw call.

Diff for: Runtime/Service.cs

@@ -49,6 +49,11 @@ public virtual void OnInitialize () { }
     /// </summary>
     public virtual void OnInitialized () { }
 
+    /// <summary>
+    /// Method invoked when the service updates, will be called every frame.
+    /// </summary>
+    public virtual void OnUpdate () { }
+
     /// <summary>
     /// Method invoked when the service is drawing the gizmos, will be called
     /// every gizmos draw call.
@@ -67,6 +72,12 @@ public virtual void OnDrawGui () { }
     /// </summary>
     public virtual void OnWillDestroy () { }
 
+    /// <summary>
+    /// Method invoked before the system will update, return whether this system
+    /// should update. will be called every frame.
+    /// </summary>
+    public virtual bool ShouldUpdate () { return true; }
+
     /// <summary>
     /// Starts a coroutine on this service.
     /// </summary>