question: public void actionPerformed ( java . awt . event . ActionEvent e ) { String command = e . getActionCommand ( ) ; if ( Debug . debugging ( "layerbuttons" ) ) { Debug . output ( "LayersPanel.actionPerformed(): " + command ) ; } if ( command == LayersPanel . LayerTopCmd || command == LayersPanel . LayerBottomCmd || command == LayersPanel . LayerUpCmd || command == LayersPanel . LayerDownCmd || command == LayersPanel . LayerRemoveCmd ) { if ( selected != null ) { if ( Debug . debugging ( "layercontrol" ) ) { Debug . output ( "LayerControlButtonPanel: button firing " + command + " event for " + selected . getName ( ) ) ; } firePropertyChange ( command , null , selected ) ; } else { if ( Debug . debugging ( "layercontrol" ) ) { Debug . output ( "LayerControlButtonPanel: button firing " + command + " event with no layer selected" ) ; } } if ( command == LayersPanel . LayerRemoveCmd ) { selected = null ; delete . setEnabled ( false ) ; } } else if ( command . equals ( LayersPanel . LayerAddCmd ) ) { if ( layerAddPanel != null ) { layerAddPanel . showPanel ( ) ; } } }
target:  Method associated with the ActionListener interface. This method listens for action events meant to change the order of the layers, as fired by the layer order buttons.