Part 1 of small refactoring to give AppState a unique ID for lookup purposes.

This is a breaking change for direct implementers of AppState as they must
add a getId() method.  (Which is also a good time to evaluate if they should
be extending AbstractAppState or BaseAppState and/or if their life cycle is
implemented correctly. e.g.: BulletAppState is breaking the AppState contract
a bit.)

jme3-bullet/src/common/java/com/jme3/bullet/BulletAppState.java

@@ -51,12 +51,25 @@ import java.util.logging.Logger;
  */
 public class BulletAppState implements AppState, PhysicsTickListener {
 
+    // FIXME: the bullet app state doesn't follow the proper AppState
+    // contract as it messes with its initialized state independently
+    // of when initialize()/cleanup() is actually called.  This means
+    // that it's quite likely that the state manager will think the
+    // app state is initialized when it, itself, doesn't.  This is
+    // a good example of why extending the abstract app state classes
+    // is better than implementing app state directly.  If it wants
+    // to support a separate stated/not-started concept then that's
+    // separate from initialized/not-initialized but way more refactoring
+    // than I want to think about today.  -pspeed:2019-09-15
+
     /**
      * true if-and-only-if the physics simulation is running (started but not
      * yet stopped)
      */
     protected boolean initialized = false;
     protected Application app;
+    private String id;
+    
     /**
      * manager that manages this state, set during attach
      */
@@ -294,6 +307,20 @@ public class BulletAppState implements AppState, PhysicsTickListener {
         return initialized;
     }
 
+    /**
+     *  Sets the unique ID of this app state.  Note: that setting
+     *  this while an app state is attached to the state manager will
+     *  have no effect on ID-based lookups.
+     */
+    protected void setId( String id ) {
+        this.id = id;
+    }
+
+    @Override
+    public String getId() {
+        return id;
+    }
+
     /**
      * Enable or disable this state.
      *

jme3-core/src/main/java/com/jme3/app/state/AbstractAppState.java

@@ -40,7 +40,7 @@ import com.jme3.renderer.RenderManager;
  * @author Kirill Vainer
  * @see com.jme3.app.state.BaseAppState
  */
-public class AbstractAppState implements AppState {
+public abstract class AbstractAppState implements AppState {
 
     /**
      * <code>initialized</code> is set to true when the method
@@ -50,38 +50,70 @@ public class AbstractAppState implements AppState {
      */
     protected boolean initialized = false;
     private boolean enabled = true;
+    private String id;
     
+    protected AbstractAppState() {    
+    }
+    
+    protected AbstractAppState( String id ) {
+        this.id = id;
+    }
+
+    @Override
     public void initialize(AppStateManager stateManager, Application app) {
         initialized = true;
     }
 
+    @Override
     public boolean isInitialized() {
         return initialized;
     }
 
+    /**
+     *  Sets the unique ID of this app state.  Note: that setting
+     *  this while an app state is attached to the state manager will
+     *  have no effect on ID-based lookups.
+     */
+    protected void setId( String id ) {
+        this.id = id;
+    }
+
+    @Override
+    public String getId() {
+        return id;
+    }
+
+    @Override
     public void setEnabled(boolean enabled) {
         this.enabled = enabled;
     }
     
+    @Override
     public boolean isEnabled() {
         return enabled;
     }
 
+    @Override
     public void stateAttached(AppStateManager stateManager) {
     }
 
+    @Override
     public void stateDetached(AppStateManager stateManager) {
     }
 
+    @Override
     public void update(float tpf) {
     }
 
+    @Override
     public void render(RenderManager rm) {
     }
 
+    @Override
     public void postRender(){
     }
 
+    @Override
     public void cleanup() {
         initialized = false;
     }

jme3-core/src/main/java/com/jme3/app/state/AppState.java

@@ -90,6 +90,12 @@ public interface AppState {
      */
     public boolean isInitialized();
 
+    /**
+     *  Returns the unique ID for this AppState or null if it has no
+     *  unique ID.
+     */
+    public String getId();
+
     /**
      * Enable or disable the functionality of the <code>AppState</code>.
      * The effect of this call depends on implementation. An 

jme3-core/src/main/java/com/jme3/app/state/BaseAppState.java

@@ -78,6 +78,14 @@ public abstract class BaseAppState implements AppState {
     private Application app;
     private boolean initialized;
     private boolean enabled = true;
+    private String id;
+
+    protected BaseAppState() {
+    }
+    
+    protected BaseAppState( String id ) {
+        this.id = id;
+    }
 
     /**
      *  Called during initialization once the app state is
@@ -133,6 +141,20 @@ public abstract class BaseAppState implements AppState {
         return initialized;
     }
 
+    /**
+     *  Sets the unique ID of this app state.  Note: that setting
+     *  this while an app state is attached to the state manager will
+     *  have no effect on ID-based lookups.
+     */
+    protected void setId( String id ) {
+        this.id = id;
+    }
+
+    @Override
+    public String getId() {
+        return id;
+    }
+
     public final Application getApplication() {
         return app;
     }

jme3-core/src/main/java/com/jme3/app/state/RootNodeAppState.java

@@ -85,6 +85,18 @@ public class RootNodeAppState extends AbstractAppState {
         this.rootNode = rootNode;
     }
 
+    /**
+     * Creates the AppState with the given unique ID, ViewPort, and root Node, attaches
+     * the root Node to the ViewPort and updates it.
+     * @param viewPort An existing ViewPort
+     * @param rootNode An existing root Node
+     */
+    public RootNodeAppState( String id, ViewPort viewPort, Node rootNode ) {
+        super(id);
+        this.viewPort = viewPort;
+        this.rootNode = rootNode;
+    }
+
     @Override
     public void initialize(AppStateManager stateManager, Application app) {
         if (rootNode == null) {
@@ -101,6 +113,12 @@ public class RootNodeAppState extends AbstractAppState {
     public void update(float tpf) {
         super.update(tpf);
         rootNode.updateLogicalState(tpf);
+        
+        // FIXME: I'm 99% sure that updateGeometricState() should be
+        // called in render() so that it is done as late as possible.
+        // In complicated app state setups, cross-state chatter could 
+        // cause nodes (or their children) to be updated after this 
+        // app state's update has been called.  -pspeed:2019-09-15 
         rootNode.updateGeometricState();
     }
 

jme3-core/src/main/java/com/jme3/cinematic/Cinematic.java

@@ -99,6 +99,7 @@ public class Cinematic extends AbstractCinematicEvent implements AppState {
     private boolean initialized = false;
     private Map<String, Map<Object, Object>> eventsData;
     private float nextEnqueue = 0;
+    private String id;
 
     /**
      * Used for serialization creates a cinematic, don't use this constructor
@@ -291,6 +292,20 @@ public class Cinematic extends AbstractCinematicEvent implements AppState {
         return initialized;
     }
 
+    /**
+     *  Sets the unique ID of this app state.  Note: that setting
+     *  this while an app state is attached to the state manager will
+     *  have no effect on ID-based lookups.
+     */
+    protected void setId( String id ) {
+        this.id = id;
+    }
+
+    @Override
+    public String getId() {
+        return id;
+    }
+
     /**
      * passing true has the same effect as play() you should use play(),
      * pause(), stop() to handle the cinematic playing state.