public int indexOf(Field field) {
    requireNonNull(field, "field cannot be null");
    Integer index = fieldIndexes.get(field);
    checkArgument(index != null, "Field '%s' not found", field);
    return index;
  }
Gets the index of the specified field.

@throws IllegalArgumentException when field is not found
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/analyzer/RelationType.java