com.espertech.esper.pattern
Class EvalStateNode

java.lang.Object
  extended by com.espertech.esper.pattern.EvalStateNode
Direct Known Subclasses:
EvalAndStateNode, EvalAuditStateNode, EvalEveryDistinctStateExpireKeyNode, EvalEveryDistinctStateNode, EvalEveryStateNode, EvalFilterStateNode, EvalFollowedByStateNode, EvalFollowedByWithMaxStateNodeManaged, EvalGuardStateNode, EvalMatchUntilStateNode, EvalNotStateNode, EvalObserverStateNode, EvalOrStateNode, EvalRootStateNode

public abstract class EvalStateNode
extends java.lang.Object

Superclass of all state nodes in an evaluation node tree representing an event expressions. Follows the Composite pattern. Subclasses are expected to keep their own collection containing child nodes as needed.


Constructor Summary
EvalStateNode(Evaluator parentNode)
          Constructor.
 
Method Summary
abstract  java.lang.Object accept(EvalStateNodeVisitor visitor, java.lang.Object data)
          Accept a visitor.
abstract  java.lang.Object childrenAccept(EvalStateNodeVisitor visitor, java.lang.Object data)
          Pass the visitor to all child nodes.
abstract  EvalNode getFactoryNode()
          Returns the factory node for the state node.
 Evaluator getParentEvaluator()
          Returns the parent evaluator.
abstract  boolean isFilterStateNode()
           
abstract  boolean isNotOperator()
           
abstract  void quit()
          Stops the event expression or an instance of it.
 void setParentEvaluator(Evaluator parentEvaluator)
          Sets the parent evaluator.
abstract  void start(MatchedEventMap beginState)
          Starts the event expression or an instance of it.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

EvalStateNode

public EvalStateNode(Evaluator parentNode)
Constructor.

Parameters:
parentNode - is the evaluator for this node on which to indicate a change in truth value
Method Detail

start

public abstract void start(MatchedEventMap beginState)
Starts the event expression or an instance of it. Child classes are expected to initialize and start any event listeners or schedule any time-based callbacks as needed.

Parameters:
beginState -

quit

public abstract void quit()
Stops the event expression or an instance of it. Child classes are expected to free resources and stop any event listeners or remove any time-based callbacks.


accept

public abstract java.lang.Object accept(EvalStateNodeVisitor visitor,
                                        java.lang.Object data)
Accept a visitor. Child classes are expected to invoke the visit method on the visitor instance passed in.

Parameters:
visitor - on which the visit method is invoked by each node
data - any additional data the visitor may need is passed in this parameter
Returns:
any additional data the visitor may need or null

childrenAccept

public abstract java.lang.Object childrenAccept(EvalStateNodeVisitor visitor,
                                                java.lang.Object data)
Pass the visitor to all child nodes.

Parameters:
visitor - is the instance to be passed to all child nodes
data - any additional data the visitor may need is passed in this parameter
Returns:
any additional data the visitor may need or null

getFactoryNode

public abstract EvalNode getFactoryNode()
Returns the factory node for the state node.

Returns:
factory node

isNotOperator

public abstract boolean isNotOperator()

isFilterStateNode

public abstract boolean isFilterStateNode()

getParentEvaluator

public final Evaluator getParentEvaluator()
Returns the parent evaluator.

Returns:
parent evaluator instance

setParentEvaluator

public final void setParentEvaluator(Evaluator parentEvaluator)
Sets the parent evaluator.

Parameters:
parentEvaluator - for this node

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