fix TParticles hierarchy with SR, #213

js/concentration/model/Particles.js

@@ -28,21 +28,12 @@ define( function( require ) {
     /**
      * Adds a particle.
      * @param {SoluteParticle} particle
-     * @public called by TParticles and subclasses
+     * @protected
      */
     addParticle: function( particle ) {
       this.particles.push( particle );
     },
 
-    /**
-     * Removes all particles.
-     * @public
-     * @abstract
-     */
-    removeAllParticles: function() {
-       throw new Error( 'must be implemented by subtype' );
-    },
-
     /**
      * Registers a listener that will be called when the collection of particles has changed in some way
      * (eg, number of particles, particles move, ...)

js/concentration/model/Precipitate.js

@@ -16,9 +16,6 @@ define( function( require ) {
   var PrecipitateParticle = require( 'BEERS_LAW_LAB/concentration/model/PrecipitateParticle' );
   var Vector2 = require( 'DOT/Vector2' );
 
-  // phet-io modules
-  var TPrecipitate = require( 'BEERS_LAW_LAB/concentration/model/TPrecipitate' );
-
   /**
    * @param {ConcentrationSolution} solution
    * @param {Beaker} beaker
@@ -49,8 +46,9 @@ define( function( require ) {
       self.updateParticles();
     } );
 
-    // Persists for the life of the sim, no need to be disposed
-    tandem.addInstance( this, { phetioType: TPrecipitate } );
+    // We're not calling tandem.addInstance for Precipitate because it doesn't add any new attributes or methods.
+    // And individual particles are derived from the model, so restoring individual particles (as part of saved
+    // state) is problematic.  See https://github.com/phetsims/beers-law-lab/issues/213
   }
 
   beersLawLab.register( 'Precipitate', Precipitate );

js/concentration/model/ShakerParticles.js

@@ -147,7 +147,6 @@ define( function( require ) {
 
     /**
      * @public
-     * @override
      */
     removeAllParticles: function() {
       var particles = this.particles.slice( 0 );

js/concentration/model/TShakerParticles.js

@@ -14,44 +14,52 @@ define( function( require ) {
   var phetioInherit = require( 'ifphetio!PHET_IO/phetioInherit' );
   var TObject = require( 'ifphetio!PHET_IO/types/TObject' );
   var TShakerParticle = require( 'BEERS_LAW_LAB/concentration/model/TShakerParticle' );
-  var TParticles = require( 'BEERS_LAW_LAB/concentration/model/TParticles' );
 
   /**
    *
-   * @param instance
+   * @param {ShakerParticles} shakerParticles
    * @param phetioID
    * @constructor
    */
-  function TShakerParticles( instance, phetioID ) {
-    assert && assertInstanceOf( instance, phet.beersLawLab.ShakerParticles );
-    TParticles.call( this, instance, phetioID );
+  function TShakerParticles( shakerParticles, phetioID ) {
+    assert && assertInstanceOf( shakerParticles, phet.beersLawLab.ShakerParticles );
+    TObject.call( this, shakerParticles, phetioID );
   }
 
   phetioInherit( TObject, 'TShakerParticles', TShakerParticles, {}, {
+
     documentation: 'Base type for a group of particles.',
 
-    clearChildInstances: function( instance ) {
-      TParticles.clearChildInstances( instance );
+    clearChildInstances: function( shakerParticles ) {
+      shakerParticles.removeAllParticles();
+
+      // Particles.step is not called in playback mode, so this needs to be called explicitly to update the view.
+      shakerParticles.fireChanged();
     },
 
     /**
      * Create a dynamic particle as specified by the phetioID and state.
-     * @param {Object} instance
+     * @param {ShakerParticles} shakerParticles
      * @param {Tandem} tandem
      * @param {Object} stateObject
      * @returns {ChargedParticle}
      */
-    addChildInstance: function( instance, tandem, stateObject ) {
+    addChildInstance: function( shakerParticles, tandem, stateObject ) {
+
       var value = TShakerParticle.fromStateObject( stateObject );
       assert && assert( value.acceleration instanceof phet.dot.Vector2, 'acceleration should be a Vector2' );
-      TParticles.addParticle( instance, new phet.beersLawLab.ShakerParticle(
+
+      shakerParticles.addParticle( new phet.beersLawLab.ShakerParticle(
         value.solute,
         value.location,
         value.orientation,
         value.velocity,
         value.acceleration,
         tandem
       ) );
+
+      // Particles.step is not called in playback mode, so this needs to be called explicitly to update the view.
+      shakerParticles.fireChanged();
     }
   } );