TreeView treeView = model.getTreeView(); if (treeView == null) { model.createTreeView(); treeView = model.getTreeView(); treeView.addPropertyChangeListener(controller); } return treeView;
return model.getTreeView();
    public TreeView getTreeView()    {        int state = model.getState();        if (state == NEW && state == DISCARDED)            throw new IllegalStateException(            		"This method cannot be invoked in the NEW "+        			"or DISCARDED state.");        TreeView treeView = model.getTreeView();        if (treeView == null) {            model.createTreeView();            treeView = model.getTreeView();            treeView.addPropertyChangeListener(controller);        }        return treeView;    }