Method pushBefore

src/org/apache/pig/impl/plan/OperatorPlan.java:1232–1363

Push one operator in front of another. This function is for use when the first operator has multiple inputs. The caller can specify which input of the first operator the second operator should be pushed to. @param first operator, assumed to have multiple inputs. @param second operator, will be pus

(E first, E second, int inputNum)

     * @throws PlanException if inputNum does not exist for first operator
     */
    public void pushBefore(E first, E second, int inputNum) throws PlanException {
        E firstNode = first;
        E secondNode = second;
        
        if(firstNode == null) {
            int errCode = 1085;
            String msg = "First operator in pushBefore is null. Cannot pushBefore null operators.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        if(secondNode == null) {
            int errCode = 1085;
            String msg = "Second operator in pushBefore is null. Cannot pushBefore null operators.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        checkInPlan(firstNode);
        checkInPlan(secondNode);
        
        List<E> firstNodePredecessors = (mToEdges.get(firstNode) == null? null : new ArrayList<E>(mToEdges.get(firstNode)));
        
        if(firstNodePredecessors == null || firstNodePredecessors.size() <= 1) {
            int size = (firstNodePredecessors == null ? 0 : firstNodePredecessors.size());
            int errCode = 1086;
            String msg = "First operator in pushBefore should have multiple inputs."
                            + " Found first operator with " + size + " inputs.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        if(inputNum >= firstNodePredecessors.size()) {
            int errCode = 1087;
            String msg = "The inputNum " + inputNum + " should be lesser than the number of inputs of the first operator."
                            + " Found first operator with " + firstNodePredecessors.size() + " inputs.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        List<E> firstNodeSuccessors = (mFromEdges.get(firstNode) == null? null : new ArrayList<E>(mFromEdges.get(firstNode)));
        
        if(firstNodeSuccessors == null) {
            int errCode = 1088;
            String msg = "First operator in pushBefore should have at least one output."
                + " Found first operator with no outputs.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        List<E> secondNodePredecessors = (mToEdges.get(secondNode) == null? null : new ArrayList<E>(mToEdges.get(secondNode)));
        
        if(secondNodePredecessors == null || secondNodePredecessors.size() > 1) {
            int size = (secondNodePredecessors == null ? 0 : secondNodePredecessors.size());
            int errCode = 1088;
            String msg = "Second operator in pushBefore should have one input."
                + " Found second operator with " + size + " inputs.";
            throw new PlanException(msg, errCode, PigException.INPUT);
        }
        
        List<E> secondNodeSuccessors = (mFromEdges.get(secondNode) == null? null : new ArrayList<E>(mFromEdges.get(secondNode)));
        
        //check for multiple edges from first to second