com.espertech.esper.epl.expression.methodagg
Class ExprFirstEverNode

java.lang.Object
  com.espertech.esper.epl.expression.core.ExprNodeBase
      com.espertech.esper.epl.expression.baseagg.ExprAggregateNodeBase
          com.espertech.esper.epl.expression.methodagg.ExprFirstEverNode

All Implemented Interfaces:

ExprAggregateNode, ExprEvaluator, ExprNode, ExprValidator, MetaDefItem, java.io.Serializable

public class ExprFirstEverNode
extends ExprAggregateNodeBase

Represents the "firstever" aggregate function is an expression tree.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.espertech.esper.epl.expression.baseagg.ExprAggregateNodeBase

aggregationResultFuture, column, isDistinct, optionalAggregateLocalGroupByDesc, positionalParams

Constructor Summary

ExprFirstEverNode(boolean distinct)
Ctor.

Method Summary

boolean	equalsNodeAggregateMethodOnly(ExprAggregateNode node) Return true if a expression aggregate node semantically equals the current node, or false if not.
java.lang.String	getAggregationFunctionName() Returns the aggregation function name for representation in a generate expression string.
boolean	hasFilter()
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.baseagg.ExprAggregateNodeBase

equalsNode, evaluate, getExprEvaluator, getFactory, getOptionalLocalGroupBy, getPositionalParams, getPrecedence, getType, isConstantResult, isDistinct, isExprTextWildcardWhenNoParams, makeExceptionExpectedParamNum, setAggregationResultFuture, toPrecedenceFreeEPL, validate, validateFilter, validateNumericChildAllowFilter, validatePositionals

Methods inherited from class com.espertech.esper.epl.expression.core.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.core.ExprNode

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

Constructor Detail

ExprFirstEverNode

public ExprFirstEverNode(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

hasFilter

public boolean hasFilter()

getAggregationFunctionName

public 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

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