public void set(BytesBytesMultiHashMap hashMap, long firstOffset, boolean hasList,
        long offsetAfterListRecordKeyLen) {

      this.hashMap = hashMap;

      this.firstOffset = firstOffset;
      this.hasList = hasList;
      this.offsetAfterListRecordKeyLen = offsetAfterListRecordKeyLen;

      // Position at first row.
      readIndex = 0;
      nextTailOffset = -1;

      hasRows = true;
    }
Set internal values for reading the values after finding a key.

@param hashMap
         The hash map we found the key in.
@param firstOffset
         The absolute offset of the first record in the write buffers.
@param hasList
         Whether there are multiple values (true) or just a single value (false).
@param offsetAfterListRecordKeyLen
         The offset of just after the key length in the list record.  Or, 0 when single row.
ql/src/java/org/apache/hadoop/hive/ql/exec/persistence/BytesBytesMultiHashMap.java