public void initGenerationSpecSchema(Random r, List<GenerationSpec> generationSpecList, int maxComplexDepth,
      boolean allowNull, boolean isUnicodeOk,
      List<DataTypePhysicalVariation> explicitDataTypePhysicalVariationList) {
    this.r = r;
    this.allowNull = allowNull;
    this.isUnicodeOk = isUnicodeOk;
    chooseSchema(
        SupportedTypes.ALL, null, generationSpecList, explicitDataTypePhysicalVariationList,
        maxComplexDepth);
  }
Generate object inspector and random row object[].
ql/src/test/org/apache/hadoop/hive/ql/exec/vector/VectorRandomRowSource.java