com.espertech.esper.epl.expression.ops
Class ExprRelationalOpNodeImpl

java.lang.Object
  com.espertech.esper.epl.expression.core.ExprNodeBase
      com.espertech.esper.epl.expression.ops.ExprRelationalOpNodeImpl

All Implemented Interfaces:

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

public class ExprRelationalOpNodeImpl
extends ExprNodeBase
implements ExprEvaluator, ExprRelationalOpNode

Represents a lesser or greater then (/>=) expression in a filter expression tree.

See Also:

Serialized Form

Constructor Summary

ExprRelationalOpNodeImpl(RelationalOpEnum relationalOpEnum)
Ctor.

Method Summary

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.
RelationalOpEnum	getRelationalOpEnum() Returns the type of relational op used.
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	toPrecedenceFreeEPL(java.io.StringWriter writer)
ExprNode	validate(ExprValidationContext validationContext)

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

ExprRelationalOpNodeImpl

public ExprRelationalOpNodeImpl(RelationalOpEnum relationalOpEnum)

Ctor.

Parameters:

relationalOpEnum - - type of compare, ie. lt, gt, le, ge

Method Detail

getExprEvaluator

public ExprEvaluator getExprEvaluator()

Specified by:

getExprEvaluator in interface ExprNode

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

getRelationalOpEnum

public RelationalOpEnum getRelationalOpEnum()

Returns the type of relational op used.

Specified by:

getRelationalOpEnum in interface ExprRelationalOpNode

Returns:

enum with relational op type

validate

public ExprNode validate(ExprValidationContext validationContext)
                  throws ExprValidationException

Specified by:

validate in interface ExprValidator

Throws:

ExprValidationException

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.

toPrecedenceFreeEPL

public void toPrecedenceFreeEPL(java.io.StringWriter writer)

Specified by:

toPrecedenceFreeEPL in class ExprNodeBase

getPrecedence

public ExprPrecedenceEnum getPrecedence()

Description copied from interface: ExprNode

Returns precedence.

Specified by:

getPrecedence in interface ExprNode

Returns:

precedence

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