question: private void expandAll ( JTree catTree , TreePath parent , boolean expand ) { TreeNode node = ( TreeNode ) parent . getLastPathComponent ( ) ; if ( node . getChildCount ( ) >= 0 ) { for ( Enumeration e = node . children ( ) ; e . hasMoreElements ( ) ; ) { TreeNode n = ( TreeNode ) e . nextElement ( ) ; TreePath path = parent . pathByAddingChild ( n ) ; expandAll ( catTree , path , expand ) ; } } if ( parent . getPathCount ( ) > 1 ) { if ( expand ) { catTree . expandPath ( parent ) ; } else { catTree . collapsePath ( parent ) ; } } }
target:  expand or collapse all nodes of the specified tree