question: @ Override public void actionPerformed ( ActionEvent e ) { Object o ; o = e . getSource ( ) ; if ( o == menuFileOpen ) { loadFile ( ) ; } else if ( o == menuFileSave ) { saveFile ( ) ; } else if ( o == menuFileSaveAs ) { saveFileAs ( ) ; } else if ( o == menuFileClose ) { closeFile ( ) ; } else if ( o == menuFileCloseAll ) { closeAllFiles ( ) ; } else if ( o == menuFileProperties ) { showProperties ( ) ; } else if ( o == menuFileExit ) { close ( ) ; } else if ( o == menuEditUndo ) { undo ( ) ; } else if ( o == menuEditCopy ) { copyContent ( ) ; } else if ( o == menuEditSearch ) { search ( ) ; } else if ( o == menuEditClearSearch ) { clearSearch ( ) ; } else if ( o == menuEditDeleteAttribute ) { deleteAttribute ( false ) ; } else if ( o == menuEditDeleteAttributes ) { deleteAttribute ( true ) ; } else if ( o == menuEditRenameAttribute ) { renameAttribute ( ) ; } else if ( o == menuEditAttributeAsClass ) { attributeAsClass ( ) ; } else if ( o == menuEditDeleteInstance ) { deleteInstance ( false ) ; } else if ( o == menuEditDeleteInstances ) { deleteInstance ( true ) ; } else if ( o == menuEditSortInstances ) { sortInstances ( ) ; } else if ( o == menuViewAttributes ) { showAttributes ( ) ; } else if ( o == menuViewValues ) { showValues ( ) ; } else if ( o == menuViewOptimalColWidths ) { setOptimalColWidths ( ) ; } updateMenu ( ) ; }
target:  invoked when an action occurs