public byte[] getValue() {
      setValue(org.apache.thrift.TBaseHelper.rightSize(value));
      return value == null ? null : value.array();
    }
the expected value to be compared against, if not provided the
check is for the non-existence of the column in question
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/generated/THBaseService.java