public void insert(double min,double max,Object item){
  if (root != null)   throw new IllegalStateException("Index cannot be added to once it has been queried");
  leaves.add(new IntervalRTreeLeafNode(min,max,item));
}

public void insert ( double min , double max , Object item ) { if ( root != null ) throw new IllegalStateException ( "Index cannot be added to once it has been queried" ) ; leaves . add ( new IntervalRTreeLeafNode ( min , max , item ) ) ; }
adds an item to the index which is associated with the given interval
