Class HistoricalTableLookupStrategy
java.lang.Object
com.espertech.esper.common.internal.epl.join.exec.base.HistoricalTableLookupStrategy
- All Implemented Interfaces:
JoinExecTableLookupStrategy
A lookup strategy for use in outer joins onto historical streams.
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Constructor Summary
ConstructorDescriptionHistoricalTableLookupStrategy
(HistoricalEventViewable viewable, PollResultIndexingStrategy indexingStrategy, HistoricalIndexLookupStrategy lookupStrategy, int numStreams, int streamNum, int rootStreamNum, ExprEvaluator outerJoinExprNode) Ctor. -
Method Summary
Modifier and TypeMethodDescriptionlookup
(EventBean theEvent, Cursor cursor, ExprEvaluatorContext exprEvaluatorContext) Returns matched events for a event to look up for.
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Constructor Details
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HistoricalTableLookupStrategy
public HistoricalTableLookupStrategy(HistoricalEventViewable viewable, PollResultIndexingStrategy indexingStrategy, HistoricalIndexLookupStrategy lookupStrategy, int numStreams, int streamNum, int rootStreamNum, ExprEvaluator outerJoinExprNode) Ctor.- Parameters:
viewable
- providing the polling accessindexingStrategy
- strategy for indexing resultslookupStrategy
- strategy for using indexed resultsnumStreams
- number of streamsstreamNum
- stream number of the historical streamrootStreamNum
- the query plan root stream numberouterJoinExprNode
- an optional outer join expression
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Method Details
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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 interfaceJoinExecTableLookupStrategy
- Parameters:
theEvent
- to look upcursor
- the path in the query that the lookup tookexprEvaluatorContext
- expression evaluation context- Returns:
- set of matching events, or null if none matching
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getStrategyDesc
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getLookupStrategyType
- Specified by:
getLookupStrategyType
in interfaceJoinExecTableLookupStrategy
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