@org.apache.thrift.annotation.Nullable
    public java.util.Iterator<java.nio.ByteBuffer> getColumnsIterator() {
      return (this.columns == null) ? null : this.columns.iterator();
    }
Returns true if field row is set (has been assigned a value) and false otherwise
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift/generated/Hbase.java