Package com.espertech.esper.common.internal.epl.expression.agg.method

Class ExprCountNode

java.lang.Object

com.espertech.esper.common.internal.epl.expression.core.ExprNodeBase

com.espertech.esper.common.internal.epl.expression.agg.base.ExprAggregateNodeBase

com.espertech.esper.common.internal.epl.expression.agg.method.ExprCountNode

All Implemented Interfaces:

ExprAggregateNode, ExprEvaluator, ExprForge, ExprForgeInstrumentable, ExprNode, ExprNodeRenderable, ExprValidator

public class ExprCountNode
extends ExprAggregateNodeBase

Represents the count(...) and count(*) and count(distinct ...) aggregate function is an expression tree.

Field Summary

Fields inherited from class com.espertech.esper.common.internal.epl.expression.agg.base.ExprAggregateNodeBase

aggregationResultFutureMemberName, column, isDistinct, optionalAggregateLocalGroupByDesc, optionalFilter, positionalParams

Fields inherited from interface com.espertech.esper.common.internal.epl.expression.core.ExprEvaluator

EPTYPE, EPTYPEARRAY

Constructor Summary

Constructors

Constructor	Description
ExprCountNode(boolean distinct)	Ctor.

Method Summary

Modifier and Type	Method	Description
final boolean	equalsNodeAggregateMethodOnly(ExprAggregateNode node)	Return true if a expression aggregate node semantically equals the current node, or false if not.
String	getAggregationFunctionName()	Returns the aggregation function name for representation in a generate expression string.
protected boolean	isFilterExpressionAsLastParameter()
boolean	isHasFilter()
AggregationForgeFactory	validateAggregationChild(ExprValidationContext validationContext)	Gives the aggregation node a chance to validate the sub-expression types.

Methods inherited from class com.espertech.esper.common.internal.epl.expression.agg.base.ExprAggregateNodeBase

equalsNode, evaluate, evaluateCodegen, evaluateCodegenUninstrumented, getAggFuture, getColumn, getEvaluationType, getExprEvaluator, getFactory, getForge, getForgeConstantType, getForgeRenderable, getOptionalFilter, getOptionalLocalGroupBy, getPositionalParams, getPrecedence, isConstantResult, isDistinct, isExprTextWildcardWhenNoParams, makeExceptionExpectedParamNum, setColumn, toPrecedenceFreeEPL, validate, validateFilter, validateNumericChildAllowFilter, validatePositionals

Methods inherited from class com.espertech.esper.common.internal.epl.expression.core.ExprNodeBase

accept, accept, acceptChildnodes, addChildNode, addChildNodes, addChildNodeToFront, checkValidated, checkValidatedException, 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.common.internal.epl.expression.core.ExprNode

accept, accept, acceptChildnodes, addChildNode, addChildNodes, getChildNodes, replaceUnlistedChildNode, setChildNode, setChildNodes

Methods inherited from interface com.espertech.esper.common.internal.epl.expression.core.ExprNodeRenderable

toEPL

Constructor Details

ExprCountNode

public ExprCountNode(boolean distinct)

Ctor.

Parameters:

distinct - - flag indicating unique or non-unique value aggregation

Method Details

validateAggregationChild

public AggregationForgeFactory 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

public 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

isHasFilter

public boolean isHasFilter()

equalsNodeAggregateMethodOnly

public final boolean equalsNodeAggregateMethodOnly(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:

equalsNodeAggregateMethodOnly in class ExprAggregateNodeBase

Parameters:

node - to compare to

Returns:

true if semantically equal, or false if not equals

isFilterExpressionAsLastParameter

protected boolean isFilterExpressionAsLastParameter()

Specified by:

isFilterExpressionAsLastParameter in class ExprAggregateNodeBase