question: @ Override public void actionPerformed ( ActionEvent e ) { Object o ; o = e . getSource ( ) ; if ( o == m_MenuFileOpen ) { loadFile ( ) ; } else if ( o == m_MenuFileSave ) { saveFile ( ) ; } else if ( o == m_MenuFileSaveAs ) { saveFileAs ( ) ; } else if ( o == m_MenuFileClose ) { closeFile ( ) ; } else if ( o == m_MenuFileCloseAll ) { closeAllFiles ( ) ; } else if ( o == m_MenuFileProperties ) { showProperties ( ) ; } else if ( o == m_MenuFileExit ) { close ( ) ; } else if ( o == m_MenuEditUndo ) { undo ( ) ; } else if ( o == m_MenuEditCopy ) { copyContent ( ) ; } else if ( o == m_MenuEditSearch ) { search ( ) ; } else if ( o == m_MenuEditClearSearch ) { clearSearch ( ) ; } else if ( o == m_MenuEditDeleteAttribute ) { deleteAttribute ( false ) ; } else if ( o == m_MenuEditDeleteAttributes ) { deleteAttribute ( true ) ; } else if ( o == m_MenuEditRenameAttribute ) { renameAttribute ( ) ; } else if ( o == m_MenuEditAttributeAsClass ) { attributeAsClass ( ) ; } else if ( o == m_MenuEditDeleteInstance ) { deleteInstance ( false ) ; } else if ( o == m_MenuEditDeleteInstances ) { deleteInstance ( true ) ; } else if ( o == m_MenuEditSortInstances ) { sortInstances ( ) ; } else if ( o == m_MenuViewAttributes ) { showAttributes ( ) ; } else if ( o == m_MenuViewValues ) { showValues ( ) ; } else if ( o == m_MenuViewOptimalColWidths ) { setOptimalColWidths ( ) ; } updateMenu ( ) ; }
target:  invoked when an action occurs