com.espertech.esper.epl.join.exec.base

Class HistoricalTableLookupStrategy

java.lang.Object

com.espertech.esper.epl.join.exec.base.HistoricalTableLookupStrategy

All Implemented Interfaces:

JoinExecTableLookupStrategy

public class HistoricalTableLookupStrategy
extends Object
implements JoinExecTableLookupStrategy

A lookup strategy for use in outer joins onto historical streams.

Constructor Summary

Constructors

Constructor and Description
HistoricalTableLookupStrategy(HistoricalEventViewable viewable, PollResultIndexingStrategy indexingStrategy, HistoricalIndexLookupStrategy lookupStrategy, int numStreams, int streamNum, int rootStreamNum, ExprEvaluator outerJoinExprNode) Ctor.

Method Summary

Modifier and Type	Method and Description
LookupStrategyDesc	getStrategyDesc()
Set<EventBean>	lookup(EventBean theEvent, Cursor cursor, ExprEvaluatorContext exprEvaluatorContext) Returns matched events for a event to look up for.

Methods inherited from class java.lang.Object

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

Constructor Detail

HistoricalTableLookupStrategy

public HistoricalTableLookupStrategy(HistoricalEventViewable viewable,
                                     PollResultIndexingStrategy indexingStrategy,
                                     HistoricalIndexLookupStrategy lookupStrategy,
                                     int numStreams,
                                     int streamNum,
                                     int rootStreamNum,
                                     ExprEvaluator outerJoinExprNode)

Ctor.

Parameters:

viewable - providing the polling access

indexingStrategy - strategy for indexing results

lookupStrategy - strategy for using indexed results

numStreams - number of streams

streamNum - stream number of the historical stream

rootStreamNum - the query plan root stream number

outerJoinExprNode - an optional outer join expression

Method Detail

lookup

public Set<EventBean> lookup(EventBean theEvent,
                             Cursor cursor,
                             ExprEvaluatorContext exprEvaluatorContext)

Description copied from interface: JoinExecTableLookupStrategy

Returns matched events for a event to look up for. Never returns an empty result set, always returns null to indicate no results.

Specified by:

lookup in interface JoinExecTableLookupStrategy

Parameters:

theEvent - to look up

cursor - the path in the query that the lookup took

exprEvaluatorContext - expression evaluation context

Returns:

set of matching events, or null if none matching

getStrategyDesc

public LookupStrategyDesc getStrategyDesc()

Specified by:

getStrategyDesc in interface JoinExecTableLookupStrategy