public int getInputColumnIndex(String name) throws HiveException {
    if (name == null) {
      throw new HiveException("Null column name");
    }
    if (!projectionColumnMap.containsKey(name)) {
      throw new HiveException(String.format("The column %s is not in the vectorization context column map %s.",
                 name, projectionColumnMap.toString()));
    }
    final int projectedColumnNum = projectionColumnMap.get(name);
    if (projectedColumnNum < 0) {
      throw new HiveException("Negative projected column number");
    }
    return projectedColumnNum;
  }
Context class for vectorization execution.
Main role is to map column names to column indices and serves as a
factory class for building vectorized expressions out of descriptors.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorizationContext.java