boolean function ( ) { return false ; }
returns true if this windowfn never needs to merge any windows . concode_field_sep long serialVersionUID concode_field_sep Coder<W> windowCoder concode_elem_sep boolean assignsToSingleWindow concode_elem_sep void mergeWindows concode_elem_sep Collection<W> assignWindows concode_elem_sep void merge concode_elem_sep Instant getOutputTime concode_elem_sep Collection<? extends BoundedWindow> windows concode_elem_sep Collection<W> windows concode_elem_sep T element concode_elem_sep Instant timestamp concode_elem_sep boolean isCompatible concode_elem_sep W getSideInputWindow