package com.espertech.esper.view.internal;
import com.espertech.esper.collection.RefCountedSet;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.view.StoppableView;
import com.espertech.esper.view.View;
import com.espertech.esper.view.ViewSupport;
import com.espertech.esper.view.CloneableView;
import com.espertech.esper.core.StatementContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* A view that represents a union of multiple data windows.
* <p>
* The view is parameterized by two or more data windows. From an external viewpoint, the
* view retains all events that is in any of the data windows (a union).
*/
public class UnionView extends ViewSupport implements LastPostObserver, CloneableView, StoppableView
{
private static final Log log = LogFactory.getLog(UnionView.class);
private final UnionViewFactory unionViewFactory;
private final EventType eventType;
private final View[] views;
private final EventBean[][] oldEventsPerView;
private final RefCountedSet<EventBean> unionWindow;
private final List<EventBean> removalEvents = new ArrayList<EventBean>();
private boolean isHasRemovestreamData;
private boolean isRetainObserverEvents;
private boolean isDiscardObserverEvents;
/**
* Ctor.
* @param factory the view factory
* @param eventType the parent event type
* @param viewList the list of data window views
*/
public UnionView(UnionViewFactory factory, EventType eventType, List<View> viewList)
{
this.unionViewFactory = factory;
this.eventType = eventType;
this.views = viewList.toArray(new View[viewList.size()]);
this.unionWindow = new RefCountedSet<EventBean>();
oldEventsPerView = new EventBean[viewList.size()][];
for (int i = 0; i < viewList.size(); i++)
{
LastPostObserverView view = new LastPostObserverView(i);
views[i].removeAllViews();
views[i].addView(view);
view.setObserver(this);
}
// recover
for (int i = 0; i < views.length; i++)
{
Iterator<EventBean> viewSnapshot = views[i].iterator();
for (;viewSnapshot.hasNext();)
{
EventBean event = viewSnapshot.next();
unionWindow.add(event);
}
}
}
public View cloneView(StatementContext statementContext)
{
return unionViewFactory.makeView(statementContext);
}
public void update(EventBean[] newData, EventBean[] oldData)
{
// The assumption is that either remove stream (named window deletes) or insert stream (new events) are indicated
if ((newData != null) && (oldData != null))
{
log.error("Union view received both insert and remove stream");
}
// add new event to union
if (newData != null)
{
for (EventBean newEvent : newData)
{
unionWindow.add(newEvent, views.length);
}
// new events must go to all views
// old events, such as when removing from a named window, get removed from all views
isHasRemovestreamData = false; // changed by observer logic to indicate new data
isRetainObserverEvents = true; // enable retain logic in observer
try
{
for (View view : views)
{
view.update(newData, oldData);
}
}
finally
{
isRetainObserverEvents = false;
}
// see if any child view has removed any events.
// if there was an insert stream, handle pushed-out events
if (isHasRemovestreamData)
{
List<EventBean> removedEvents = null;
// process each buffer
for (int i = 0; i < oldEventsPerView.length; i++)
{
if (oldEventsPerView[i] == null)
{
continue;
}
EventBean[] viewOldData = oldEventsPerView[i];
oldEventsPerView[i]= null; // clear entry
// remove events for union, if the last event was removed then add it
for (EventBean old : viewOldData)
{
boolean isNoMoreRef = unionWindow.remove(old);
if (isNoMoreRef)
{
if (removedEvents == null)
{
removalEvents.clear();
removedEvents = removalEvents;
}
removedEvents.add(old);
}
}
}
if (removedEvents != null)
{
oldData = removedEvents.toArray(new EventBean[removedEvents.size()]);
}
}
// indicate new and, possibly, old data
updateChildren(newData, oldData);
}
// handle remove stream
else if (oldData != null)
{
isDiscardObserverEvents = true; // disable reaction logic in observer
try
{
for (View view : views)
{
view.update(null, oldData);
}
}
finally
{
isDiscardObserverEvents = false;
}
// remove from union
for (EventBean oldEvent : oldData)
{
unionWindow.removeAll(oldEvent);
}
updateChildren(null, oldData);
}
}
public EventType getEventType()
{
return eventType;
}
public Iterator<EventBean> iterator()
{
return unionWindow.keyIterator();
}
public void newData(int streamId, EventBean[] newEvents, EventBean[] oldEvents)
{
if ((oldEvents == null) || (isDiscardObserverEvents))
{
return;
}
if (isRetainObserverEvents)
{
oldEventsPerView[streamId] = oldEvents;
isHasRemovestreamData = true;
return;
}
// handle time-based removal
List<EventBean> removedEvents = null;
// remove events for union, if the last event was removed then add it
for (EventBean old : oldEvents)
{
boolean isNoMoreRef = unionWindow.remove(old);
if (isNoMoreRef)
{
if (removedEvents == null)
{
removalEvents.clear();
removedEvents = removalEvents;
}
removedEvents.add(old);
}
}
if (removedEvents != null)
{
EventBean[] removed = removedEvents.toArray(new EventBean[removedEvents.size()]);
updateChildren(null, removed);
}
}
@Override
public void stop() {
for (View view : views) {
if (view instanceof StoppableView) {
((StoppableView) view).stop();
}
}
}
}