Method disconnect

src/org/apache/pig/newplan/BaseOperatorPlan.java:255–273

Disconnect two operators in the plan. @param from Operator edge is coming from @param to Operator edge is going to @return pair of positions, indicating the position in the from and to arrays. @throws FrontendException if the two operators aren't connected.

(Operator from,
                                             Operator to)

     * @throws FrontendException if the two operators aren't connected.
     */
    public Pair<Integer, Integer> disconnect(Operator from,
                                             Operator to) throws FrontendException {
        Pair<Operator, Integer> f = fromEdges.removeWithPosition(from, to);
        if (f == null) { 
            throw new FrontendException("Attempt to disconnect operators " + 
                from.getName() + " and " + to.getName() +
                " which are not connected.", 2219);
        }
        
        Pair<Operator, Integer> t = toEdges.removeWithPosition(to, from);
        if (t == null) { 
            throw new FrontendException("Plan in inconssistent state " + 
                from.getName() + " and " + to.getName() +
                " connected in fromEdges but not toEdges.", 2220);
        }
        
        markDirty();
        return new Pair<Integer, Integer>(f.second, t.second);
    }

    private void markDirty() {
        roots.clear();