question: private void updateEnabled ( ) { removeFileButton . setEnabled ( ( ! engine . isRunning ( ) ) && fileList . getSelectedIndices ( ) . length > 0 ) ; runSelectedButton . setEnabled ( ( ! engine . isRunning ( ) ) && fileList . getSelectedIndices ( ) . length > 0 ) ; runAllButton . setEnabled ( ! engine . isRunning ( ) ) ; addFileButton . setEnabled ( ! engine . isRunning ( ) ) ; }
target:  Sets the enabled state of the buttons.