public static VectorExpressionWriter[] genVectorStructExpressionWritables(
      StructObjectInspector oi) throws HiveException {
    VectorExpressionWriter[] writers = new VectorExpressionWriter[oi.getAllStructFieldRefs().size()];
    final List<? extends StructField> fields = oi.getAllStructFieldRefs();
    int i = 0;
    for(StructField field : fields) {
      writers[i++] = genVectorExpressionWritable(field.getFieldObjectInspector());
    }
    return writers;
  }
Compiles the appropriate vector expression writers based on a struct object
inspector.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/VectorExpressionWriterFactory.java