com.espertech.esper.epl.expression.funcs

Class ExprInstanceofNode

java.lang.Object

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

com.espertech.esper.epl.expression.funcs.ExprInstanceofNode

All Implemented Interfaces:

ExprEvaluator, ExprNode, ExprValidator, MetaDefItem, Serializable

public class ExprInstanceofNode
extends ExprNodeBase
implements ExprEvaluator

Represents the INSTANCEOF(a,b,...) function is an expression tree.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ExprInstanceofNode(String[] classIdentifiers) 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.
Object	evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext) Evaluate event tuple and return result.
String[]	getClassIdentifiers() Returns the list of class names or types to check instance of.
ExprEvaluator	getExprEvaluator()
ExprPrecedenceEnum	getPrecedence() Returns precedence.
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(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

ExprInstanceofNode

public ExprInstanceofNode(String[] classIdentifiers)

Ctor.

Parameters:

classIdentifiers - is a list of type names to check type for

Method Detail

getExprEvaluator

public ExprEvaluator getExprEvaluator()

Specified by:

getExprEvaluator in interface ExprNode

validate

public ExprNode validate(ExprValidationContext validationContext)
                  throws ExprValidationException

Specified by:

validate in interface ExprValidator

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.

Specified by:

isConstantResult in interface ExprNode

Returns:

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

getType

public 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 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(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,
                          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.

Specified by:

equalsNode in interface ExprNode

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

getClassIdentifiers

public String[] getClassIdentifiers()

Returns the list of class names or types to check instance of.

Returns:

class names