AbstractCellImg: Create a lambda that executes only once for update

this.createView will initially determine whether parameter A is of
type DataAccess or not. Subsequent calls will use a memoized version.

src/main/java/net/imglib2/img/cell/AbstractCellImg.java

@@ -62,7 +62,7 @@ public abstract class AbstractCellImg<
 
 	protected final I cells;
 
-	private final BiFunction< A, Object, A > createView;
+	private BiFunction< A, Object, A > createView;
 
 	@SuppressWarnings( "unchecked" )
 	public AbstractCellImg( final CellGrid grid, final I imgOfCells, final Fraction entitiesPerPixel )
@@ -71,14 +71,24 @@ public AbstractCellImg( final CellGrid grid, final I imgOfCells, final Fraction
 		this.grid = grid;
 		this.cells = imgOfCells;
 
-		if ( imgOfCells.firstElement().getData() instanceof DataAccess )
-		{
-			this.createView = ( data, cursor ) -> ( A ) ( ( DataAccess ) data ).createView( cursor );
-		}
-		else
-		{
-			this.createView = ( data, cursor ) -> data;
-		}
+		/*
+		 * On the first execution, determine if we use DataAccess.createView or
+		 * just return data. Subsequent executions in this instance of
+		 * AbstractCellImg will not need to evaluate the instanceof statement.
+		 */
+		this.createView = ( d, c ) -> {
+			// Executed only once per AbstractCellImg instance
+			if ( d instanceof DataAccess )
+			{
+				this.createView = ( data, cursor ) -> ( A ) ( ( DataAccess ) data ).createView( cursor );
+			}
+			else
+			{
+				this.createView = ( data, cursor ) -> data;
+			}
+			// Apply the new lambda function
+			return this.createView.apply( d, c );
+		};
 	}
 
 	/**