com.espertech.esper.epl.expression
Class ExprNthAggNode

java.lang.Object
  extended by com.espertech.esper.epl.expression.ExprNodeBase
      extended by com.espertech.esper.epl.expression.ExprAggregateNodeBase
          extended by com.espertech.esper.epl.expression.ExprNthAggNode
All Implemented Interfaces:
ExprAggregateNode, ExprEvaluator, ExprNode, ExprValidator, MetaDefItem, java.io.Serializable

public class ExprNthAggNode
extends ExprAggregateNodeBase

Represents the nth(...) and aggregate function is an expression tree.

See Also:
Serialized Form

Field Summary
 
Fields inherited from class com.espertech.esper.epl.expression.ExprAggregateNodeBase
aggregationResultFuture, column, isDistinct
 
Constructor Summary
ExprNthAggNode(boolean distinct)
          Ctor.
 
Method Summary
 boolean equalsNodeAggregate(ExprAggregateNode node)
          Return true if a expression aggregate node semantically equals the current node, or false if not.
protected  java.lang.String getAggregationFunctionName()
          Returns the aggregation function name for representation in a generate expression string.
 AggregationMethodFactory validateAggregationChild(ExprValidationContext validationContext)
          Gives the aggregation node a chance to validate the sub-expression types.
 
Methods inherited from class com.espertech.esper.epl.expression.ExprAggregateNodeBase
equalsNode, evaluate, getExprEvaluator, getFactory, getPrecedence, getType, isConstantResult, isDistinct, setAggregationResultFuture, toPrecedenceFreeEPL, validate, validateFilter, validateNumericChildAllowFilter
 
Methods inherited from class com.espertech.esper.epl.expression.ExprNodeBase
accept, accept, acceptChildnodes, addChildNode, addChildNodes, addChildNodeToFront, getChildNodes, replaceUnlistedChildNode, setChildNode, setChildNodes, toEPL
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.espertech.esper.epl.expression.ExprNode
accept, accept, acceptChildnodes, addChildNode, addChildNodes, getChildNodes, replaceUnlistedChildNode, setChildNode, setChildNodes, toEPL
 

Constructor Detail

ExprNthAggNode

public ExprNthAggNode(boolean distinct)
Ctor.

Parameters:
distinct - - flag indicating unique or non-unique value aggregation
Method Detail

validateAggregationChild

public AggregationMethodFactory validateAggregationChild(ExprValidationContext validationContext)
                                                  throws ExprValidationException
Description copied from class: ExprAggregateNodeBase
Gives the aggregation node a chance to validate the sub-expression types.

Specified by:
validateAggregationChild in class ExprAggregateNodeBase
Parameters:
validationContext - validation information
Returns:
aggregation function factory to use
Throws:
ExprValidationException - when expression validation failed

getAggregationFunctionName

protected java.lang.String getAggregationFunctionName()
Description copied from class: ExprAggregateNodeBase
Returns the aggregation function name for representation in a generate expression string.

Specified by:
getAggregationFunctionName in class ExprAggregateNodeBase
Returns:
aggregation function name

equalsNodeAggregate

public final boolean equalsNodeAggregate(ExprAggregateNode node)
Description copied from class: ExprAggregateNodeBase
Return true if a expression aggregate node semantically equals the current node, or false if not.

For use by the equalsNode implementation which compares the distinct flag.

Specified by:
equalsNodeAggregate in class ExprAggregateNodeBase
Parameters:
node - to compare to
Returns:
true if semantically equal, or false if not equals

© 2006-2014 EsperTech Inc.
All rights reserved.
Visit us at espertech.com