Method put

src/org/apache/pig/parser/LogicalPlanBuilder.java:115–119

(String k, Operator v)

    private Map<String, Operator> operators = new HashMap<String, Operator>() {
        @Override
        public Operator put(String k, Operator v) {
            lastRel = k;
            return super.put(k, v);
        }
    };

    Map<String, String> fileNameMap;