public void putDependency(Operator<? extends OperatorDesc> op,
        ColumnInfo col, Dependency dep) {
      Map<ColumnInfo, Dependency> colMap = depMap.get(op);
      if (colMap == null) {
        colMap = new LinkedHashMap<ColumnInfo, Dependency>();
        depMap.put(op, colMap);
      }
      colMap.put(col, dep);
    }
Puts the dependency for an operator, columninfo tuple.
@param op The operator whose dependency is being inserted.
@param col The column info whose dependency is being inserted.
@param dep The dependency.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/lineage/LineageCtx.java