com.espertech.esper.epl.expression.core
Class ExprNodeValidated

java.lang.Object
  com.espertech.esper.epl.expression.core.ExprNodeBase
      com.espertech.esper.epl.expression.core.ExprNodeValidated

All Implemented Interfaces:

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

public class ExprNodeValidated
extends ExprNodeBase
implements ExprEvaluator

A placeholder for another expression node that has been validated already.

See Also:

Serialized Form

Constructor Summary

ExprNodeValidated(ExprNode inner)
Ctor.

Method Summary

void	accept(ExprNodeVisitor visitor) Accept the visitor.
boolean	equalsNode(ExprNode node) Return true if a expression node semantically equals the current node, or false if not.
java.lang.Object	evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext) Evaluate event tuple and return result.
ExprEvaluator	getExprEvaluator()
ExprPrecedenceEnum	getPrecedence() Returns precedence.
java.lang.Class	getType() Returns the type that the node's evaluate method returns an instance of.
boolean	isConstantResult() Returns true if the expression node's evaluation value doesn't depend on any events data, as must be determined at validation time, which is bottom-up and therefore reliably allows each node to determine constant value.
void	toEPL(java.io.StringWriter writer, ExprPrecedenceEnum parentPrecedence)
void	toPrecedenceFreeEPL(java.io.StringWriter writer)
ExprNode	validate(ExprValidationContext validationContext)

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

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExprNodeValidated

public ExprNodeValidated(ExprNode inner)

Ctor.

Parameters:

inner - nested expression node

Method Detail

getExprEvaluator

public ExprEvaluator getExprEvaluator()

Specified by:

getExprEvaluator in interface ExprNode

getPrecedence

public ExprPrecedenceEnum getPrecedence()

Description copied from interface: ExprNode

Returns precedence.

Specified by:

getPrecedence in interface ExprNode

Returns:

precedence

toEPL

public void toEPL(java.io.StringWriter writer,
                  ExprPrecedenceEnum parentPrecedence)

Specified by:

toEPL in interface ExprNode

Overrides:

toEPL in class ExprNodeBase

toPrecedenceFreeEPL

public void toPrecedenceFreeEPL(java.io.StringWriter writer)

Specified by:

toPrecedenceFreeEPL in class ExprNodeBase

isConstantResult

public boolean isConstantResult()

Description copied from interface: ExprNode

Returns true if the expression node's evaluation value doesn't depend on any events data, as must be determined at validation time, which is bottom-up and therefore reliably allows each node to determine constant value.

Specified by:

isConstantResult in interface ExprNode

Returns:

true for constant evaluation value, false for non-constant evaluation value

equalsNode

public boolean equalsNode(ExprNode node)

Description copied from interface: ExprNode

Return true if a expression node semantically equals the current node, or false if not.

Concrete implementations should compare the type and any additional information that impact the evaluation of a node.

Specified by:

equalsNode in interface ExprNode

Parameters:

node - to compare to

Returns:

true if semantically equal, or false if not equals

validate

public ExprNode validate(ExprValidationContext validationContext)
                  throws ExprValidationException

Specified by:

validate in interface ExprValidator

Throws:

ExprValidationException

accept

public void accept(ExprNodeVisitor visitor)

Description copied from interface: ExprNode

Accept the visitor. The visitor will first visit the parent then visit all child nodes, then their child nodes.

The visitor can decide to skip child nodes by returning false in isVisit.

Specified by:

accept in interface ExprNode

Overrides:

accept in class ExprNodeBase

Parameters:

visitor - to visit each node and each child node.

getType

public java.lang.Class getType()

Description copied from interface: ExprEvaluator

Returns the type that the node's evaluate method returns an instance of.

Specified by:

getType in interface ExprEvaluator

Returns:

type returned when evaluated

evaluate

public java.lang.Object evaluate(EventBean[] eventsPerStream,
                                 boolean isNewData,
                                 ExprEvaluatorContext exprEvaluatorContext)

Description copied from interface: ExprEvaluator

Evaluate event tuple and return result.

Specified by:

evaluate in interface ExprEvaluator

Parameters:

eventsPerStream - - event tuple

isNewData - - indicates whether we are dealing with new data (istream) or old data (rstream)

exprEvaluatorContext - context for expression evaluation

Returns:

evaluation result, a boolean value for OR/AND-type evalution nodes.