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AggregationMultiFunctionHandlerAggregationStateUniqueKey Property

Return a state-key object that determines how the runtime shares aggregation state between multiple aggregation functions that may appear in the same EPL statement.

The runtime applies equals-semantics to determine state sharing. If two instances are equal (implement hashCode and equals) then the runtime shares a single aggregation state instance for the two aggregation function expressions.

If your aggregation function never needs shared state simple return {@code new AggregationStateKey(){}}.

If your aggregation function always shares state simple declare {@code private static final AggregationStateKey MY_KEY = new AggregationStateKey() {};} and {@code return MY_KEY}; (if using multiple handlers declare the key on the factory level).

Namespace:  com.espertech.esper.common.client.hook.aggmultifunc
Assembly:  NEsper.Common (in NEsper.Common.dll) Version: 8.0.0.0
Syntax
C#
AggregationMultiFunctionStateKey AggregationStateUniqueKey { get; }

Property Value

Type: AggregationMultiFunctionStateKey
state key
See Also