public boolean isSet(_Fields field) {
    if (field == null) {
      throw new java.lang.IllegalArgumentException();
    }

    switch (field) {
    case ROW:
      return isSetRow();
    case COLUMNS:
      return isSetColumns();
    case TIMESTAMP:
      return isSetTimestamp();
    case TIME_RANGE:
      return isSetTimeRange();
    case MAX_VERSIONS:
      return isSetMaxVersions();
    case FILTER_STRING:
      return isSetFilterString();
    case ATTRIBUTES:
      return isSetAttributes();
    case AUTHORIZATIONS:
      return isSetAuthorizations();
    case CONSISTENCY:
      return isSetConsistency();
    case TARGET_REPLICA_ID:
      return isSetTargetReplicaId();
    case CACHE_BLOCKS:
      return isSetCacheBlocks();
    case STORE_LIMIT:
      return isSetStoreLimit();
    case STORE_OFFSET:
      return isSetStoreOffset();
    case EXISTENCE_ONLY:
      return isSetExistence_only();
    case FILTER_BYTES:
      return isSetFilterBytes();
    }
    throw new java.lang.IllegalStateException();
  }
Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/generated/TGet.java