/*
***************************************************************************************
* 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.epl.join.assemble;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.epl.join.rep.Node;
import com.espertech.esper.util.IndentWriter;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* Assembly node for an event stream that is a branch with a single optional child node below it.
*/
public class BranchOptionalAssemblyNode extends BaseAssemblyNode {
private List<Node> resultsForStream;
// For tracking when we only have a single event for this stream as a result
private Node singleResultNode;
private EventBean singleResultEvent;
private boolean haveChildResults;
// For tracking when we have multiple events for this stream
private Set<EventBean> completedEvents;
/**
* Ctor.
*
* @param streamNum - is the stream number
* @param numStreams - is the number of streams
*/
public BranchOptionalAssemblyNode(int streamNum, int numStreams) {
super(streamNum, numStreams);
}
public void init(List<Node>[] result) {
resultsForStream = result[streamNum];
singleResultNode = null;
singleResultEvent = null;
haveChildResults = false;
if (resultsForStream != null) {
int numNodes = resultsForStream.size();
if (numNodes == 1) {
Node node = resultsForStream.get(0);
Set<EventBean> nodeEvents = node.getEvents();
// If there is a single result event (typical case)
if (nodeEvents.size() == 1) {
singleResultNode = node;
singleResultEvent = nodeEvents.iterator().next();
}
}
if (singleResultNode == null) {
completedEvents = new HashSet<EventBean>();
}
}
}
public void process(List<Node>[] result, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
// there cannot be child nodes to compute a cartesian product if this node had no results
if (resultsForStream == null) {
return;
}
// If this node's result set consisted of a single event
if (singleResultNode != null) {
// If there are no child results, post a row
if (!haveChildResults) {
EventBean[] row = new EventBean[numStreams];
row[streamNum] = singleResultEvent;
parentNode.result(row, streamNum, singleResultNode.getParentEvent(), singleResultNode, resultFinalRows, resultRootEvent);
}
// if there were child results we are done since they have already been posted to the parent
return;
}
// We have multiple events for this node, generate an event row for each event not yet received from
// event rows generated by the child node.
for (Node node : resultsForStream) {
Set<EventBean> events = node.getEvents();
for (EventBean theEvent : events) {
if (completedEvents.contains(theEvent)) {
continue;
}
processEvent(theEvent, node, resultFinalRows, resultRootEvent);
}
}
}
public void result(EventBean[] row, int fromStreamNum, EventBean myEvent, Node myNode, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
row[streamNum] = myEvent;
Node parentResultNode = myNode.getParent();
parentNode.result(row, streamNum, myNode.getParentEvent(), parentResultNode, resultFinalRows, resultRootEvent);
// record the fact that an event that was generated by a child
haveChildResults = true;
// If we had more then on result event for this stream, we need to track all the different events
// generated by the child node
if (singleResultNode == null) {
completedEvents.add(myEvent);
}
}
public void print(IndentWriter indentWriter) {
indentWriter.println("BranchOptionalAssemblyNode streamNum=" + streamNum);
}
private void processEvent(EventBean theEvent, Node currentNode, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
EventBean[] row = new EventBean[numStreams];
row[streamNum] = theEvent;
parentNode.result(row, streamNum, currentNode.getParentEvent(), currentNode.getParent(), resultFinalRows, resultRootEvent);
}
}