/*
***************************************************************************************
* 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.LinkedList;
import java.util.List;
/**
* Assembly node for an event stream that is a root with a two or more child nodes below it.
*/
public class RootCartProdAssemblyNode extends BaseAssemblyNode {
private final int[] childStreamIndex; // maintain mapping of stream number to index in array
private final List<EventBean[]>[] rowsPerStream;
private final boolean allSubStreamsOptional;
// maintain for each child the list of stream number descending that child
private int[][] subStreamsNumsPerChild;
private int[][] combinedSubStreams; // for any cartesian product past 2 streams
private boolean haveChildResults;
/**
* Ctor.
*
* @param streamNum - is the stream number
* @param numStreams - is the number of streams
* @param allSubStreamsOptional - true if all substreams are optional and none are required
* @param childStreamIndex indexes for child streams
*/
public RootCartProdAssemblyNode(int streamNum, int numStreams, boolean allSubStreamsOptional, int[] childStreamIndex) {
super(streamNum, numStreams);
this.allSubStreamsOptional = allSubStreamsOptional;
this.childStreamIndex = childStreamIndex;
rowsPerStream = new List[numStreams];
}
public void init(List<Node>[] result) {
if (subStreamsNumsPerChild == null) {
if (childNodes.size() < 2) {
throw new IllegalStateException("Expecting at least 2 child nodes");
}
subStreamsNumsPerChild = new int[childNodes.size()][];
for (int i = 0; i < childNodes.size(); i++) {
subStreamsNumsPerChild[i] = childNodes.get(i).getSubstreams();
}
combinedSubStreams = computeCombined(subStreamsNumsPerChild);
}
haveChildResults = false;
for (int i = 0; i < rowsPerStream.length; i++) {
rowsPerStream[i] = null;
}
}
public void process(List<Node>[] result, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
// If no child has posted any rows, generate row and done
if ((!haveChildResults) && allSubStreamsOptional) {
// post an empty row
EventBean[] row = new EventBean[numStreams];
parentNode.result(row, streamNum, null, null, resultFinalRows, resultRootEvent);
return;
}
// Compute the cartesian product
postCartesian(rowsPerStream, resultFinalRows, resultRootEvent);
}
public void result(EventBean[] row, int fromStreamNum, EventBean myEvent, Node myNode, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
haveChildResults = true;
// fill event in
row[streamNum] = myEvent;
int childStreamArrIndex = childStreamIndex[fromStreamNum];
// keep a reference to the row to build a cartesian product on the call to process
List<EventBean[]> rows = rowsPerStream[childStreamArrIndex];
if (rows == null) {
rows = new LinkedList<EventBean[]>();
rowsPerStream[childStreamArrIndex] = rows;
}
rows.add(row);
}
public void print(IndentWriter indentWriter) {
indentWriter.println("RootCartProdAssemblyNode streamNum=" + streamNum);
}
private void postCartesian(List<EventBean[]>[] rowsPerStream, Collection<EventBean[]> resultFinalRows, EventBean resultRootEvent) {
List<EventBean[]> result = new LinkedList<EventBean[]>();
CartesianUtil.computeCartesian(
rowsPerStream[0], subStreamsNumsPerChild[0],
rowsPerStream[1], subStreamsNumsPerChild[1],
result);
if (rowsPerStream.length > 2) {
for (int i = 0; i < subStreamsNumsPerChild.length - 2; i++) {
List<EventBean[]> product = new LinkedList<EventBean[]>();
CartesianUtil.computeCartesian(
result, combinedSubStreams[i],
rowsPerStream[i + 2], subStreamsNumsPerChild[i + 2],
product);
result = product;
}
}
for (EventBean[] row : result) {
parentNode.result(row, streamNum, null, null, resultFinalRows, resultRootEvent);
}
}
/**
* Compute an array of supersets of sub stream numbers per stream, for at least 3 or more streams.
*
* @param subStreamsPerChild is for each stream number a list of direct child sub streams
* @return an array in with length (subStreamsPerChild.lenght - 2) in which
* array[0] contains the streams for subStreamsPerChild[0] and subStreamsPerChild[1] combined, and
* array[1] contains the streams for subStreamsPerChild[0], subStreamsPerChild[1] and subStreamsPerChild[2] combined
*/
protected static int[][] computeCombined(int[][] subStreamsPerChild) {
if (subStreamsPerChild.length < 3) {
return null;
}
// Add all substreams of (1 + 2) up into = Sum3
// Then add all substreams of (Sum3 + 3) => Sum4
// Results in an array of size (subStreamsPerChild.lenght - 2) containing Sum3, Sum4 etc
int[][] result = new int[subStreamsPerChild.length - 2][];
result[0] = addSubstreams(subStreamsPerChild[0], subStreamsPerChild[1]);
for (int i = 0; i < subStreamsPerChild.length - 3; i++) {
result[i + 1] = addSubstreams(result[i], subStreamsPerChild[i + 2]);
}
return result;
}
private static int[] addSubstreams(int[] arrayOne, int[] arrayTwo) {
int[] result = new int[arrayOne.length + arrayTwo.length];
int count = 0;
for (int i = 0; i < arrayOne.length; i++) {
result[count] = arrayOne[i];
count++;
}
for (int i = 0; i < arrayTwo.length; i++) {
result[count] = arrayTwo[i];
count++;
}
return result;
}
}