Package org.apache.hadoop.yarn.server.timelineservice.storage.common

Interface RowKeyPrefix<R>

Type Parameters:

R - indicating the type of rowkey that a particular implementation is a prefix for.

All Known Implementing Classes:

ApplicationRowKeyPrefix, EntityRowKeyPrefix, FlowActivityRowKeyPrefix, FlowRunRowKeyPrefix, SubApplicationRowKeyPrefix

public interface RowKeyPrefix<R>

In queries where a single result is needed, an exact rowkey can be used through the corresponding rowkey#getRowKey() method. For queries that need to scan over a range of rowkeys, a partial (the initial part) of rowkeys are used. Classes implementing RowKeyPrefix indicate that they are the initial part of rowkeys, with different constructors with fewer number of argument to form a partial rowkey, a prefix.

Method Summary

Modifier and Type	Method	Description
byte[]	getRowKeyPrefix()	Create a row key prefix, meaning a partial rowkey that can be used in range scans.

Method Detail

getRowKeyPrefix

byte[] getRowKeyPrefix()

Create a row key prefix, meaning a partial rowkey that can be used in range scans. Which fields are included in the prefix will depend on the constructor of the specific instance that was used. Output depends on which constructor was used.

Returns:

a prefix of the following form fist!second!...!last!