org.apache.druid.frame.key

Class RowKeyReader

java.lang.Object

org.apache.druid.frame.key.RowKeyReader

public class RowKeyReader
extends Object

Embeds the logic to read RowKey from a particular signature of row-based frame. Stateless and immutable.

Method Summary

Modifier and Type	Method and Description
static RowKeyReader	create(RowSignature signature) Creates a new RowKeyReader.
static int	fieldEndPosition(byte[] keyBytes, int fieldNumber)
boolean	hasMultipleValues(RowKey key, int fieldNumber) Determine if a particular field of a particular key has multiple values.
List<Object>	read(RowKey key) Read all values out of a key, as a list of objects.
Object	read(RowKey key, int fieldNumber) Read a value out of a key.
RowKey	trim(RowKey key, int trimmedFieldCount) Trim a key to a particular fieldCount.
RowKeyReader	trimmedKeyReader(int trimmedFieldCount) Trims the key reader to a particular fieldCount.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

create

public static RowKeyReader create(RowSignature signature)

Creates a new RowKeyReader.

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)