com.espertech.esper.epl.expression.funcs

Class ExprCaseNode

java.lang.Object

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

com.espertech.esper.epl.expression.funcs.ExprCaseNode

All Implemented Interfaces:

ExprNode, ExprNodeRenderable, ExprValidator, MetaDefItem, Serializable

public class ExprCaseNode
extends ExprNodeBase

Represents the case-when-then-else control flow function is an expression tree.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ExprCaseNode.CaseAnalysis

Constructor Summary

Constructors

Constructor and Description
ExprCaseNode(boolean isCase2) Ctor.

Method Summary

Modifier and Type	Method and Description
boolean	equalsNode(ExprNode node, boolean ignoreStreamPrefix) Return true if a expression node semantically equals the current node, or false if not.
ExprEvaluator	getExprEvaluator()
ExprForge	getForge()
ExprPrecedenceEnum	getPrecedence() Returns precedence.
boolean	isCase2() Returns true if this is a switch-type case.
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(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

Constructor Detail

ExprCaseNode

public ExprCaseNode(boolean isCase2)

Ctor.

Parameters:

isCase2 - is an indicator of which Case statement we are working on.

True indicates a 'Case2' statement with syntax "case a when a1 then b1 else b2".

False indicates a 'Case1' statement with syntax "case when a=a1 then b1 else b2".

Method Detail

getExprEvaluator

public ExprEvaluator getExprEvaluator()

getForge

public ExprForge getForge()

isCase2

public boolean isCase2()

Returns true if this is a switch-type case.

Returns:

true for switch-type case, or false for when-then type

validate

public ExprNode validate(ExprValidationContext validationContext)
                  throws ExprValidationException

Throws:

ExprValidationException

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.

Returns:

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

equalsNode

public boolean equalsNode(ExprNode node,
                          boolean ignoreStreamPrefix)

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.

Parameters:

node - to compare to

ignoreStreamPrefix - when the equals-comparison can ignore prefix of event properties

Returns:

true if semantically equal, or false if not equals

toPrecedenceFreeEPL

public void toPrecedenceFreeEPL(StringWriter writer)

Specified by:

toPrecedenceFreeEPL in class ExprNodeBase

getPrecedence

public ExprPrecedenceEnum getPrecedence()

Description copied from interface: ExprNode

Returns precedence.

Returns:

precedence