net.esper.eql.view
Class FilterExprView

java.lang.Object
  extended by net.esper.view.ViewSupport
      extended by net.esper.eql.view.FilterExprView
All Implemented Interfaces:
java.lang.Iterable<EventBean>, EventCollection, View, Viewable

public class FilterExprView
extends ViewSupport

Simple filter view filtering events using a filter expression tree.


Field Summary
 
Fields inherited from class net.esper.view.ViewSupport
parent
 
Constructor Summary
FilterExprView(ExprEvaluator exprEvaluator)
          Ctor.
 
Method Summary
 java.lang.String attachesTo(Viewable parentViewable)
          Return null if the view will accept being attached to a particular object.
protected static EventBean[] filterEvents(ExprEvaluator exprEvaluator, EventBean[] events)
          Filters events using the supplied evaluator.
 EventType getEventType()
          Provides metadata information about the type of object the event collection contains.
 java.util.Iterator<EventBean> iterator()
          Allows iteration through all elements in this event collection.
 void update(EventBean[] newData, EventBean[] oldData)
          Notify that data has been added or removed from the Viewable parent.
 
Methods inherited from class net.esper.view.ViewSupport
addView, dumpChildViews, dumpUpdateParams, findDescendent, getParent, getViews, hasViews, removeView, setParent, shallowCopyView, updateChildren, updateChildren
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

FilterExprView

public FilterExprView(ExprEvaluator exprEvaluator)
Ctor.

Parameters:
exprEvaluator - - Filter expression evaluation impl
Method Detail

getEventType

public EventType getEventType()
Description copied from interface: EventCollection
Provides metadata information about the type of object the event collection contains.

Returns:
metadata for the objects in the collection

iterator

public java.util.Iterator<EventBean> iterator()
Description copied from interface: EventCollection
Allows iteration through all elements in this event collection. The iterator will return the elements in the collection in their natural order, or, if there is no natural ordering, in some unpredictable order.

Returns:
an iterator which will go through all current elements in the collection.

attachesTo

public java.lang.String attachesTo(Viewable parentViewable)
Description copied from interface: View
Return null if the view will accept being attached to a particular object.

Parameters:
parentViewable - is the potential parent for this view
Returns:
null if this view can successfully attach to the parent, an error message if it cannot.

update

public void update(EventBean[] newData,
                   EventBean[] oldData)
Description copied from interface: View
Notify that data has been added or removed from the Viewable parent. The last object in the newData array of objects would be the newest object added to the parent view. The first object of the oldData array of objects would be the oldest object removed from the parent view. If the call to update contains new (inserted) data, then the first argument will be a non-empty list and the second will be empty. Similarly, if the call is a notification of deleted data, then the first argument will be empty and the second will be non-empty. Either the newData or oldData will be non-null. This method won't be called with both arguments being null, but either one could be null. The same is true for zero-length arrays. Either newData or oldData will be non-empty. If both are non-empty, then the update is a modification notification. When update() is called on a view by the parent object, the data in newData will be in the collection of the parent, and its data structures will be arranged to reflect that. The data in oldData will not be in the parent's data structures, and any access to the parent will indicate that that data is no longer there.

Parameters:
newData - is the new data that has been added to the parent view
oldData - is the old data that has been removed from the parent view

filterEvents

protected static EventBean[] filterEvents(ExprEvaluator exprEvaluator,
                                          EventBean[] events)
Filters events using the supplied evaluator.

Parameters:
exprEvaluator - - evaluator to use
events - - events to filter
Returns:
filtered events, or null if no events got through the filter