Package org.apache.druid.frame.key

Class RowKeyReader

  • public class RowKeyReader
extends Object
    Embeds the logic to read RowKey from a particular signature of row-based frame. Stateless and immutable.

    • Method Detail

      • read

        public Object read​(RowKey key,
                   int fieldNumber)
        Read a value out of a key. This operation is potentially costly and should not be done for every row. Implementations need not be optimized, and may do more work than strictly necessary in order to keep implementation simple.

      • read

        public List<Object> read​(RowKey key)
        Read all values out of a key, as a list of objects. This operation is potentially costly and should not be done for every row. Implementations need not be optimized, and may do more work than strictly necessary in order to keep implementation simple.

      • hasMultipleValues

        public boolean hasMultipleValues​(RowKey key,
                                 int fieldNumber)
        Determine if a particular field of a particular key has multiple values. Faster than calling read(RowKey, int).

      • trimmedKeyReader

        public RowKeyReader trimmedKeyReader​(int trimmedFieldCount)
        Trims the key reader to a particular fieldCount. Used to read keys trimmed by trim(RowKey, int).

      • trim

        public RowKey trim​(RowKey key,
                   int trimmedFieldCount)
        Trim a key to a particular fieldCount. The returned key may be a copy, but is not guaranteed to be.

      • fieldEndPosition

        public static int fieldEndPosition​(byte[] keyBytes,
                                   int fieldNumber)