com.espertech.esper.epl.expression.core

Class ExprStreamUnderlyingNodeImpl

java.lang.Object

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

com.espertech.esper.epl.expression.core.ExprStreamUnderlyingNodeImpl

All Implemented Interfaces:

ExprEvaluator, ExprNode, ExprStreamRefNode, ExprStreamUnderlyingNode, ExprValidator, MetaDefItem, Serializable

public class ExprStreamUnderlyingNodeImpl
extends ExprNodeBase
implements ExprEvaluator, ExprStreamUnderlyingNode

Represents an stream selector that returns the streams underlying event, or null if undefined.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
ExprStreamUnderlyingNodeImpl(String streamName, boolean isWildcard)

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.
EventType	getEventType()
ExprEvaluator	getExprEvaluator()
ExprPrecedenceEnum	getPrecedence() Returns precedence.
String	getRootPropertyNameIfAny()
int	getStreamId() Returns stream id supplying the property value.
String	getStreamName() Returns the stream name.
Integer	getStreamReferencedIfAny()
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)
String	toString()
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, 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

ExprStreamUnderlyingNodeImpl

public ExprStreamUnderlyingNodeImpl(String streamName,
                                    boolean isWildcard)

Method Detail

getExprEvaluator

public ExprEvaluator getExprEvaluator()

Specified by:

getExprEvaluator in interface ExprNode

getStreamName

public String getStreamName()

Returns the stream name.

Returns:

stream name

getStreamReferencedIfAny

public Integer getStreamReferencedIfAny()

Specified by:

getStreamReferencedIfAny in interface ExprStreamRefNode

getRootPropertyNameIfAny

public String getRootPropertyNameIfAny()

Specified by:

getRootPropertyNameIfAny in interface ExprStreamRefNode

validate

public ExprNode validate(ExprValidationContext validationContext)
                  throws ExprValidationException

Specified by:

validate in interface ExprValidator

Throws:

ExprValidationException

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

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

getStreamId

public int getStreamId()

Returns stream id supplying the property value.

Specified by:

getStreamId in interface ExprStreamUnderlyingNode

Returns:

stream number

toString

public String toString()

Overrides:

toString in class Object

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

getEventType

public EventType getEventType()

Specified by:

getEventType in interface ExprStreamUnderlyingNode

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