com.espertech.esper.pattern
Class EvalRootStateNode

java.lang.Object
  extended by com.espertech.esper.pattern.EvalStateNode
      extended by com.espertech.esper.pattern.EvalRootStateNode
All Implemented Interfaces:
EvalRootState, Evaluator, PatternStopCallback, StopCallback

public final class EvalRootStateNode
extends EvalStateNode
implements Evaluator, PatternStopCallback, EvalRootState

This class is always the root node in the evaluation state tree representing any activated event expression. It hold the handle to a further state node with subnodes making up a whole evaluation state tree.


Constructor Summary
EvalRootStateNode(EvalNode rootSingleChildNode, MatchedEventMap beginState, PatternContext context)
          Constructor.
 
Method Summary
 Object accept(EvalStateNodeVisitor visitor, Object data)
          Accept a visitor.
 Object childrenAccept(EvalStateNodeVisitor visitor, Object data)
          Pass the visitor to all child nodes.
 void evaluateFalse(EvalStateNode fromNode)
          Indicate a change in truth value to false.
 void evaluateTrue(MatchedEventMap matchEvent, EvalStateNode fromNode, boolean isQuitted)
          Indicate a change in truth value to true.
 void quit()
          Stops the event expression or an instance of it.
 void setCallback(PatternMatchCallback callback)
          Hands the callback to use to indicate matching events.
 void start()
          Starts the event expression or an instance of it.
 void stop()
          Stops the underlying resources.
 String toString()
           
 
Methods inherited from class com.espertech.esper.pattern.EvalStateNode
getFactoryNode, getParentEvaluator, getStateObjectId, setParentEvaluator
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

EvalRootStateNode

public EvalRootStateNode(EvalNode rootSingleChildNode,
                         MatchedEventMap beginState,
                         PatternContext context)
Constructor.

Parameters:
rootSingleChildNode - is the root nodes single child node
beginState - contains the events that make up prior matches
context - contains handles to services required
Method Detail

setCallback

public final void setCallback(PatternMatchCallback callback)
Hands the callback to use to indicate matching events.

Specified by:
setCallback in interface EvalRootState
Parameters:
callback - is invoked when the event expressions turns true.

start

public final void start()
Description copied from class: EvalStateNode
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.

Specified by:
start in class EvalStateNode

stop

public final void stop()
Description copied from interface: StopCallback
Stops the underlying resources.

Specified by:
stop in interface StopCallback

quit

public final void quit()
Description copied from class: EvalStateNode
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.

Specified by:
quit in class EvalStateNode

evaluateTrue

public final void evaluateTrue(MatchedEventMap matchEvent,
                               EvalStateNode fromNode,
                               boolean isQuitted)
Description copied from interface: Evaluator
Indicate a change in truth value to true.

Specified by:
evaluateTrue in interface Evaluator
Parameters:
matchEvent - is the container for events that caused the change in truth value
fromNode - is the node that indicates the change
isQuitted - is an indication of whether the node continues listenening or stops listening

evaluateFalse

public final void evaluateFalse(EvalStateNode fromNode)
Description copied from interface: Evaluator
Indicate a change in truth value to false.

Specified by:
evaluateFalse in interface Evaluator
Parameters:
fromNode - is the node that indicates the change

accept

public final Object accept(EvalStateNodeVisitor visitor,
                           Object data)
Description copied from class: EvalStateNode
Accept a visitor. Child classes are expected to invoke the visit method on the visitor instance passed in.

Specified by:
accept in class EvalStateNode
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 final Object childrenAccept(EvalStateNodeVisitor visitor,
                                   Object data)
Description copied from class: EvalStateNode
Pass the visitor to all child nodes.

Specified by:
childrenAccept in class EvalStateNode
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

toString

public final String toString()
Overrides:
toString in class Object

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