/*
***************************************************************************************
* Copyright (C) 2006 EsperTech, Inc. All rights reserved. *
* http://www.espertech.com/esper *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
***************************************************************************************
*/
package com.espertech.esper.view.window;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.collection.ViewUpdatedCollection;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.metrics.instrumentation.InstrumentationHelper;
import com.espertech.esper.view.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayDeque;
import java.util.Iterator;
/**
* A data view that aggregates events in a stream and releases them in one batch when a maximum number of events has
* been collected.
* <p>
* The view works similar to a length_window but is not continuous, and similar to a time_batch however is not time-based
* but reacts to the number of events.
* <p>
* The view releases the batched events, when a certain number of batched events has been reached or exceeded,
* as new data to child views. The prior batch if
* not empty is released as old data to any child views. The view doesn't release intervals with no old or new data.
* It also does not collect old data published by a parent view.
* <p>
* If there are no events in the current and prior batch, the view will not invoke the update method of child views.
*/
public class LengthBatchView extends ViewSupport implements CloneableView, DataWindowView {
// View parameters
protected final AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext;
private final LengthBatchViewFactory lengthBatchViewFactory;
private final int size;
private final ViewUpdatedCollection viewUpdatedCollection;
// Current running windows
protected ArrayDeque<EventBean> lastBatch = null;
protected ArrayDeque<EventBean> currentBatch = new ArrayDeque<EventBean>();
/**
* Constructor.
*
* @param size is the number of events to batch
* @param viewUpdatedCollection is a collection that the view must update when receiving events
* @param lengthBatchViewFactory for copying this view in a group-by
* @param agentInstanceViewFactoryContext context
*/
public LengthBatchView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext,
LengthBatchViewFactory lengthBatchViewFactory,
int size,
ViewUpdatedCollection viewUpdatedCollection) {
this.agentInstanceViewFactoryContext = agentInstanceViewFactoryContext;
this.lengthBatchViewFactory = lengthBatchViewFactory;
this.size = size;
this.viewUpdatedCollection = viewUpdatedCollection;
if (size <= 0) {
throw new IllegalArgumentException("Invalid size parameter, size=" + size);
}
}
public View cloneView() {
return lengthBatchViewFactory.makeView(agentInstanceViewFactoryContext);
}
/**
* Returns the number of events to batch (data window size).
*
* @return batch size
*/
public final int getSize() {
return size;
}
public final EventType getEventType() {
return parent.getEventType();
}
public void update(EventBean[] newData, EventBean[] oldData) {
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().qViewProcessIRStream(this, lengthBatchViewFactory.getViewName(), newData, oldData);
}
// we don't care about removed data from a prior view
if ((newData == null) || (newData.length == 0)) {
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().aViewProcessIRStream();
}
return;
}
// add data points to the current batch
for (EventBean newEvent : newData) {
currentBatch.add(newEvent);
}
// check if we reached the minimum size
if (currentBatch.size() < size) {
// done if no overflow
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().aViewProcessIRStream();
}
return;
}
sendBatch();
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().aViewProcessIRStream();
}
}
/**
* This method updates child views and clears the batch of events.
*/
protected void sendBatch() {
// If there are child views and the batch was filled, fireStatementStopped update method
if (this.hasViews()) {
// Convert to object arrays
EventBean[] newData = null;
EventBean[] oldData = null;
if (!currentBatch.isEmpty()) {
newData = currentBatch.toArray(new EventBean[currentBatch.size()]);
}
if ((lastBatch != null) && (!lastBatch.isEmpty())) {
oldData = lastBatch.toArray(new EventBean[lastBatch.size()]);
}
// update view buffer to serve expressions require access to events held
if (viewUpdatedCollection != null) {
viewUpdatedCollection.update(newData, oldData);
}
// Post new data (current batch) and old data (prior batch)
if ((newData != null) || (oldData != null)) {
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().qViewIndicate(this, lengthBatchViewFactory.getViewName(), newData, oldData);
}
updateChildren(newData, oldData);
if (InstrumentationHelper.ENABLED) {
InstrumentationHelper.get().aViewIndicate();
}
}
}
lastBatch = currentBatch;
currentBatch = new ArrayDeque<EventBean>();
}
/**
* Returns true if the window is empty, or false if not empty.
*
* @return true if empty
*/
public boolean isEmpty() {
if (lastBatch != null) {
if (!lastBatch.isEmpty()) {
return false;
}
}
return currentBatch.isEmpty();
}
public final Iterator<EventBean> iterator() {
return currentBatch.iterator();
}
public final String toString() {
return this.getClass().getName() +
" size=" + size;
}
public void visitView(ViewDataVisitor viewDataVisitor) {
viewDataVisitor.visitPrimary(currentBatch, true, lengthBatchViewFactory.getViewName(), null);
viewDataVisitor.visitPrimary(lastBatch, true, lengthBatchViewFactory.getViewName(), null);
}
public ViewFactory getViewFactory() {
return lengthBatchViewFactory;
}
private static final Logger log = LoggerFactory.getLogger(LengthBatchView.class);
}