net.esper.eql.agg
Class AggregationServiceFactory

java.lang.Object
  extended by net.esper.eql.agg.AggregationServiceFactory

public class AggregationServiceFactory
extends Object

Factory for aggregation service instances.

Consolidates aggregation nodes such that result futures point to a single instance and no re-evaluation of the same result occurs.


Constructor Summary
AggregationServiceFactory()
           
 
Method Summary
static AggregationService getService(List<ExprAggregateNode> selectAggregateExprNodes, List<ExprAggregateNode> havingAggregateExprNodes, List<ExprAggregateNode> orderByAggregateExprNodes, boolean hasGroupByClause, MethodResolutionService methodResolutionService)
          Returns an instance to handle the aggregation required by the aggregation expression nodes, depending on whether there are any group-by nodes.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

AggregationServiceFactory

public AggregationServiceFactory()
Method Detail

getService

public static AggregationService getService(List<ExprAggregateNode> selectAggregateExprNodes,
                                            List<ExprAggregateNode> havingAggregateExprNodes,
                                            List<ExprAggregateNode> orderByAggregateExprNodes,
                                            boolean hasGroupByClause,
                                            MethodResolutionService methodResolutionService)
Returns an instance to handle the aggregation required by the aggregation expression nodes, depending on whether there are any group-by nodes.

Parameters:
selectAggregateExprNodes - - aggregation nodes extracted out of the select expression
havingAggregateExprNodes - - aggregation nodes extracted out of the select expression
orderByAggregateExprNodes - - aggregation nodes extracted out of the select expression
hasGroupByClause - - indicator on whethere there is group-by required, or group-all
methodResolutionService - - is required to resolve aggregation methods
Returns:
instance for aggregation handling

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