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