net.esper.pattern
Class EvalRootNode

java.lang.Object
  extended by net.esper.pattern.EvalNode
      extended by net.esper.pattern.EvalRootNode
All Implemented Interfaces:
PatternStarter

public final class EvalRootNode
extends EvalNode
implements PatternStarter

This class is always the root node in the evaluation tree representing an event expression. It hold the handle to the EPStatement implementation for notifying when matches are found.


Constructor Summary
EvalRootNode()
           
 
Method Summary
 EvalStateNode newState(Evaluator parentNode, MatchedEventMap beginState, PatternContext context)
          Create the evaluation state node containing the truth value state for each operator in an event expression.
 PatternStopCallback start(PatternMatchCallback callback, PatternContext context)
          An event expression was started and supplies the callback to use when matching events appear.
 java.lang.String toString()
           
 
Methods inherited from class net.esper.pattern.EvalNode
addChildNode, dumpDebug, getChildNodes
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

EvalRootNode

public EvalRootNode()
Method Detail

start

public final PatternStopCallback start(PatternMatchCallback callback,
                                       PatternContext context)
Description copied from interface: PatternStarter
An event expression was started and supplies the callback to use when matching events appear. Returns the callback to use to stop the event expression.

Specified by:
start in interface PatternStarter
Parameters:
callback - must be supplied to indicate what to call when the expression turns true
context - is the context for handles to services required for evaluation.
Returns:
a callback to stop the expression again

newState

public final EvalStateNode newState(Evaluator parentNode,
                                    MatchedEventMap beginState,
                                    PatternContext context)
Description copied from class: EvalNode
Create the evaluation state node containing the truth value state for each operator in an event expression.

Specified by:
newState in class EvalNode
Parameters:
parentNode - is the parent evaluator node that this node indicates a change in truth value to
beginState - is the container for events that makes up the start state
context - is the handle to services required for evaluation
Returns:
state node containing the truth value state for the operator

toString

public final java.lang.String toString()
Overrides:
toString in class java.lang.Object