Break the CODE!!!: March 2013

Sunday, March 31, 2013

Neo4j Graph Case Study - Facebook & Trip Planner

NoSQL Graph Database - Neo4j

Graphs are everywhere - social networks, routing algorithms, payment flow, and many more. Facebook friends, Twitter followers, LinkedIn graph are a few scenarios for Graph. Quite recently Facebook released Social Graph search. Neo4j is an open source NOSQL Graph database, immensely popular and being used by companies like Adobe, Intuit. Twitter uses FlockDB for the Graphs.

Download and extract Neo4j Community edition from http://www.neo4j.org/download. Start the server by running /bin/Neo4j.bat. The Neo4j monitoring tool can be accessed from http://localhost:7474/webadmin/. The monitoring tool provides several utilities as shown below.

Gremlin - A Groovy tool for querying Graph data

Neo4j Monitoring console

Neo4j Data Browser

Apart from the above utilities, Neo4j provides support for Graph Query language called Cypher. Since Ne04j is built on Java, it runs on JVM and can be used as a Embedded database. Or it could be used as a standalone database, through REST api. There is another interesting tool called Neoclipse which is very rich in visualizing Graphs. The following Graphs for facebook friends and railway routes are generated with Neoclipse.

Applications of Neo4j

1. Facebook friend connect

Login to Facebook and follow the instructions from here to download the Facebook Graph data.
Next, run the following program to download the Profile photos from Facebook to your local machine. The photos are used only for visualization purpose for neoclipse. This step uses the data downloaded from the previous step. change the "file" variable.

	package com.raj.facebook.photos;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.FileOutputStream;
	import java.io.FileReader;
	import java.net.URL;
	import java.nio.channels.Channels;
	import java.nio.channels.ReadableByteChannel;

	public class PhotoFetcher {


	public static void main(String[] args) throws Exception {
	String dir = "C:\\Project\\workspace\\FacebookGraph\\resources\\images\\";
	File file = new File("C:\\Project\\workspace\\FacebookGraph\\resources\\Raju Ramakrishna_1364522831.graphml");
	BufferedReader br = new BufferedReader(new FileReader(file));
	String line = br.readLine();
	String url = null;
	String name = null;
	while( line != null ) {
	if( line.indexOf("<data key=\"pic_big\">") != -1 ) {
	if(line.indexOf(".jpg") != -1)
	url = line.substring(line.indexOf("http:"), line.indexOf(".jpg")+4);
	else
	url = line.substring(line.indexOf("http:"), line.indexOf(".gif")+4);
	URL picUrl = new URL(url);
	File outFile = new File(dir+ name + ".jpg");
	ReadableByteChannel rbc = Channels.newChannel(picUrl.openStream());
	FileOutputStream fos = new FileOutputStream(outFile);
	fos.getChannel().transferFrom(rbc, 0, 1 << 24);
	fos.close();
	}
	if( line.indexOf("node id") != -1) {
	name = line.substring(10, line.length()-2);
	}
	line = br.readLine();
	if( line.indexOf("edge id") != -1) {
	break;
	}
	}
	br.close();
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

The next step is to import the graph data to Neo4j. Run the below program. I have used the data for two Facebook profiles and loaded all the friends and interconnection data.

	package com.raj.facebook.graph;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.FileReader;

	import org.neo4j.graphalgo.GraphAlgoFactory;
	import org.neo4j.graphalgo.PathFinder;
	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.Node;
	import org.neo4j.graphdb.Path;
	import org.neo4j.graphdb.Relationship;
	import org.neo4j.graphdb.RelationshipType;
	import org.neo4j.graphdb.Transaction;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;
	import org.neo4j.graphdb.index.IndexHits;
	import org.neo4j.kernel.Traversal;

	public class GraphUtils {

	public static final String DB_PATH="c://apps//neo4j-1.8.2//facebook";
	public static GraphDatabaseService graphDb = null;
	public static final String ID = "id";
	public static final String USER = "user:";

	public static void main(String[] args) throws Exception {
	new GraphUtils().createGraph();
	}

	public void createGraph() throws Exception {

	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );
	File file = new File("C:\\Project\\workspace\\FacebookGraph\\resources\\Raju Ramakrishna_1364522831.graphml");
	BufferedReader br = new BufferedReader(new FileReader(file));
	String line = br.readLine();
	Node node = null;
	String key = null;
	String val = null;
	String source = null;
	String target = null;

	Transaction tx = graphDb.beginTx();
	Node myself = graphDb.createNode();
	myself.setProperty("fb_id", "Raju_Ramakrishna_100000243684316");
	myself.setProperty("uid", "100000243684316");
	myself.setProperty("name", "Raju Ramakrishna");
	myself.setProperty("sex", "male");
	myself.setProperty("mutual_friends", 27);
	myself.setProperty("likes", 16);
	myself.setProperty("friend_count", 180);

	graphDb.index().forNodes("myfriends").add(myself, "fb_id", "Raju_Ramakrishna_100000243684316");
	while( line != null ) {
	if(line.indexOf("node id") != -1) {
	val = line.substring(line.indexOf("node id")+9, line.length()-2);
	System.out.println("ID=" +val);
	node = graphDb.createNode();
	node.setProperty("fb_id", val);
	graphDb.index().forNodes("myfriends").add(node, "fb_id", val);
	Relationship relationship = myself.createRelationshipTo(node, RelTypes.FRIEND);
	relationship.setProperty("link", myself.getProperty("fb_id") + " <==> " +node.getProperty("fb_id"));
	} else if(line.indexOf("</node>") != -1) {
	System.out.println("----------");
	} else if(line.indexOf("data key") != -1){
	if(line.indexOf("uid") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Label = " +val);
	node.setProperty("uid", val);
	} else if(line.indexOf("name") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Name = " +val);
	node.setProperty("name", val);
	} else if(line.indexOf("sex") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Sex = " +val);
	node.setProperty("sex", val);
	} else if(line.indexOf("mutual_friend_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Mutual Friends = " +val);
	node.setProperty("mutual_friends", val);
	} else if(line.indexOf("likes_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Likes = " +val);
	node.setProperty("likes", val);
	} else if(line.indexOf("friend_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Friends = " +val);
	node.setProperty("friend_count", val);
	} else if(line.indexOf("pic_big") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("picture = " +val);
	// node.setProperty("picture", val);
	}
	} else if(line.indexOf("edge id") != -1) {
	source = line.substring(line.indexOf("source")+8, line.indexOf("target")-2);
	target = line.substring(line.indexOf("target")+8, line.indexOf("</edge>")-2);
	System.out.println(source+ " ---- " +target);
	Node sourceNode = graphDb.index().forNodes("myfriends").get("fb_id", source).next();
	Node targetNode = graphDb.index().forNodes("myfriends").get("fb_id", target).next();
	Relationship relationship = sourceNode.createRelationshipTo(targetNode, RelTypes.FRIEND);
	relationship.setProperty("link", sourceNode.getProperty("fb_id") + " <==> " +targetNode.getProperty("fb_id"));
	}
	line = br.readLine();
	}

	br.close();

	file = new File("C:\\Project\\workspace\\FacebookGraph\\resources\\Geeta Raj_1364532420.graphml");
	br = new BufferedReader(new FileReader(file));
	line = br.readLine();

	boolean nodeFound = false;
	myself = graphDb.index().forNodes("myfriends").get("fb_id", "Geeta_Raj_556485423").next();

	while( line != null ) {
	if(line.indexOf("node id") != -1) {
	val = line.substring(line.indexOf("node id")+9, line.length()-2);
	System.out.println("ID=" +val);
	IndexHits<Node> nodes = graphDb.index().forNodes("myfriends").get("fb_id", val);
	if( nodes.hasNext() ) {
	node = nodes.next();
	nodeFound = true;
	} else {
	node = graphDb.createNode();
	node.setProperty("fb_id", val);
	graphDb.index().forNodes("myfriends").add(node, "fb_id", val);
	Relationship relationship = myself.createRelationshipTo(node, RelTypes.FRIEND);
	relationship.setProperty("link", myself.getProperty("fb_id") + " <==> " +node.getProperty("fb_id"));
	}
	} else if(line.indexOf("</node>") != -1) {
	nodeFound = false;
	System.out.println("----------");
	} else if( !nodeFound && line.indexOf("data key") != -1){
	if(line.indexOf("uid") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Label = " +val);
	node.setProperty("uid", val);
	} else if(line.indexOf("name") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Name = " +val);
	node.setProperty("name", val);
	} else if(line.indexOf("sex") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Sex = " +val);
	node.setProperty("sex", val);
	} else if(line.indexOf("mutual_friend_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Mutual Friends = " +val);
	node.setProperty("mutual_friends", val);
	} else if(line.indexOf("likes_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Likes = " +val);
	node.setProperty("likes", val);
	} else if(line.indexOf("friend_count") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("Friends = " +val);
	node.setProperty("friend_count", val);
	} else if(line.indexOf("pic_big") != -1) {
	key = "CDATA";
	val = line.substring(line.indexOf(key)+key.length()+1, line.indexOf("</data>")-3);
	System.out.println("picture = " +val);
	// node.setProperty("picture", val);
	}
	} else if(line.indexOf("edge id") != -1) {
	source = line.substring(line.indexOf("source")+8, line.indexOf("target")-2);
	target = line.substring(line.indexOf("target")+8, line.indexOf("</edge>")-2);
	System.out.println(source+ " ---- " +target);
	Node sourceNode = graphDb.index().forNodes("myfriends").get("fb_id", source).next();
	Node targetNode = graphDb.index().forNodes("myfriends").get("fb_id", target).next();

	//Only if there is no link already
	PathFinder<Path> finder = GraphAlgoFactory.shortestPath(
	Traversal.expanderForTypes( RelTypes.FRIEND ), 1 );
	Iterable<Path> paths = finder.findAllPaths( sourceNode, targetNode );
	if(!paths.iterator().hasNext()) {
	Relationship relationship = sourceNode.createRelationshipTo(targetNode, RelTypes.FRIEND);
	relationship.setProperty("link", sourceNode.getProperty("fb_id") + " <==> " +targetNode.getProperty("fb_id"));
	}
	}
	line = br.readLine();
	}

	br.close();

	tx.success();
	tx.finish();
	}


	public static enum RelTypes implements RelationshipType {
	FRIEND
	}



	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	// Registers a shutdown hook for the Neo4j instance so that it
	// shuts down nicely when the VM exits (even if you "Ctrl-C" the
	// running example before it's completed)
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

Now the data is ready, I implemented a search utility which - given 2 Facebook IDs, it will provide all posible ways for the 2 people to get connected.

	package com.raj.facebook.graph;

	import org.neo4j.graphalgo.GraphAlgoFactory;
	import org.neo4j.graphalgo.PathFinder;
	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.Node;
	import org.neo4j.graphdb.Path;
	import org.neo4j.graphdb.Relationship;
	import org.neo4j.graphdb.RelationshipType;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;
	import org.neo4j.kernel.Traversal;

	public class SearchFriends {

	public static final String DB_PATH="c://apps//neo4j-1.8.2//facebook";
	public static GraphDatabaseService graphDb = null;
	public static final String ID = "id";
	public static final String USER = "user:";

	public static void main(String[] args) throws Exception {
	new SearchFriends().search();
	}

	public void search() throws Exception {

	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );

	Node you = graphDb.index().forNodes("myfriends").get("fb_id", "Raju_Ramakrishna_100000243684316").next();
	Node me = graphDb.index().forNodes("myfriends").get("fb_id", "Geeta_Madye_1178898406").next();

	PathFinder<Path> finder = GraphAlgoFactory.shortestPath(
	Traversal.expanderForTypes( RelTypes.FRIEND ), 2 );
	Iterable<Path> paths = finder.findAllPaths( you, me );
	for( Path path: paths ) {
	for( Relationship relation: path.relationships()) {
	System.out.println(relation.getProperty("link"));
	}
	System.out.println();
	}
	}


	public static enum RelTypes implements RelationshipType {
	FRIEND
	}



	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	// Registers a shutdown hook for the Neo4j instance so that it
	// shuts down nicely when the VM exits (even if you "Ctrl-C" the
	// running example before it's completed)
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

2. Railway Trip Planner

For this application, I used data from Indian Railways site. A few trains were randomly chosen and their routes and information were stored in local file system as a tab-delimited text. The route information contains station code, names, distances, time taken etc. I created directories with name as train number. Each directory contains info.csv and schedule.csv. Download it and save the directories and its contents locally. It can be downloaded from here

Next, run the below program to import the graph data to Neo4j.

	package com.raj.railways;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.FileReader;

	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.Node;
	import org.neo4j.graphdb.Relationship;
	import org.neo4j.graphdb.RelationshipType;
	import org.neo4j.graphdb.Transaction;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;
	import org.neo4j.graphdb.index.IndexHits;

	public class DataLoader {

	public static final String DB_PATH="c://apps//neo4j-1.8.2//indianrail";
	public static GraphDatabaseService graphDb = null;

	/**
	* @param args
	*/
	public static void main(String[] args) throws Exception {

	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );

	Transaction tx = graphDb.beginTx();
	String loc = "C:\\Project\\dataset\\indian-railways\\";
	File mainDir = new File(loc);
	String[] dirs = mainDir.list();
	for( String s: dirs ) {
	File dir = new File(loc+"\\"+s);
	// System.out.println(dir.getName());
	File file = new File(loc + "\\" +s+ "\\info.csv");
	BufferedReader br = new BufferedReader(new FileReader(file));
	String line = br.readLine();
	String trainNumber = null;
	String trainName = null;

	while(line != null) {
	line = br.readLine();
	if( line != null ) {
	String[] sArr = line.split("\t");
	trainNumber = sArr[0];
	trainName = sArr[1];
	System.out.println(trainNumber+":"+trainName);
	}
	}
	br.close();

	Train train = new Train( trainNumber, trainName );

	file = new File(loc + "\\" +s+ "\\schedule.csv");
	br = new BufferedReader(new FileReader(file));
	line = br.readLine();
	int dist = -1;
	Node previousNode = null;

	while(line != null) {
	line = br.readLine();
	if( line != null ) {
	String[] sArr = line.split("\t");
	String stationCode = sArr[1];
	String stationName = sArr[2];
	int totalDist = Integer.parseInt(sArr[7]);
	if( dist == -1 ) {
	dist =0;
	}
	System.out.println(stationCode+":"+stationName+ " ~ " +(totalDist-dist));

	IndexHits<Node> nodes = graphDb.index().forNodes("station").get("code", stationCode);
	Node node = null;
	if( nodes.hasNext() ) {
	node = nodes.next();
	String trains = (String)node.getProperty("trains");
	trains = trains + "\|" +train.toString();
	node.setProperty("trains", trains);
	} else {
	node = graphDb.createNode();
	node.setProperty("code", stationCode);
	node.setProperty("name", stationName);
	node.setProperty("trains", train.toString());
	graphDb.index().forNodes("station").add( node, "code", stationCode);
	}

	if( previousNode != null ) {
	String prevCode = (String)previousNode.getProperty("code");
	String relation = prevCode + "-" +stationCode;
	if(!graphDb.index().forRelationships("route").get("path", relation).hasNext()) {
	Relationship relationship = previousNode.createRelationshipTo(node, RelTypes.ROUTE);
	relationship.setProperty("distance", (totalDist-dist));
	graphDb.index().forRelationships("route").add(relationship, "path", relation);
	}
	}

	dist = totalDist;
	previousNode = node;
	}
	}

	br.close();
	}

	tx.success();
	tx.finish();
	}

	public static enum RelTypes implements RelationshipType {
	ROUTE
	}



	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	// Registers a shutdown hook for the Neo4j instance so that it
	// shuts down nicely when the VM exits (even if you "Ctrl-C" the
	// running example before it's completed)
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}

	}


	class Train {

	String trainNumber;
	String trainName;

	public Train(String trainNumber, String trainName) {
	super();
	this.trainNumber = trainNumber;
	this.trainName = trainName;
	}

	public String toString() {
	return trainNumber + "~" +trainName;
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

Now the data is available, I created a trip planner. It provides 2 options - Search for a path between 2 stations with least distance, Search for a path between 2 stations with least number of stops. In each case print the total distance.

	package com.raj.railways;

	import java.util.HashSet;
	import java.util.Set;

	import org.neo4j.graphalgo.GraphAlgoFactory;
	import org.neo4j.graphalgo.PathFinder;
	import org.neo4j.graphalgo.WeightedPath;
	import org.neo4j.graphdb.Direction;
	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.Node;
	import org.neo4j.graphdb.Path;
	import org.neo4j.graphdb.Relationship;
	import org.neo4j.graphdb.RelationshipType;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;
	import org.neo4j.kernel.Traversal;

	public class TrainSearch {


	public static final String DB_PATH="c://apps//neo4j-1.8.2//indianrail";
	public static GraphDatabaseService graphDb = null;

	/**
	* @param args
	*/
	public static void main(String[] args) throws Exception {

	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );
	new TrainSearch().search("SBC", "UBL");
	System.out.println();
	new TrainSearch().search("UBL", "BGM");
	}


	public void search( String code1, String code2 ) {

	System.out.println("**************************************");

	Node source = graphDb.index().forNodes("station").get("code", code1).next();
	Node target = graphDb.index().forNodes("station").get("code", code2).next();

	System.out.println("SOURCE: " +source.getProperty("name")+ " DESTINATION: " +target.getProperty("name"));

	//Get Least number of stops
	System.out.println();
	System.out.println("Route for least number of Stops");
	PathFinder<Path> finder = GraphAlgoFactory.shortestPath(
	Traversal.expanderForTypes( RelTypes.ROUTE ), 200 );
	Path path = finder.findAllPaths( source, target ).iterator().next();

	int total = 0;

	for(Node node : path.nodes()) {
	System.out.print(node.getProperty("name") + " -> ");
	}

	System.out.println();

	for( Relationship relation: path.relationships()) {
	total += (int)relation.getProperty("distance");
	}


	System.out.println();
	System.out.println("Distance = " +total+ " KM");


	PathFinder<WeightedPath> weightedFinder = GraphAlgoFactory.dijkstra(
	Traversal.expanderForTypes( RelTypes.ROUTE, Direction.BOTH ), "distance" );

	WeightedPath weightedPath = weightedFinder.findSinglePath( source, target );

	// Get the weight for the found path
	double weight = weightedPath.weight();

	System.out.println();
	System.out.println("Route for minimum distance");
	for(Node node : weightedPath.nodes()) {
	System.out.print(node.getProperty("name") + " -> ");
	}

	System.out.println();

	System.out.println("Distance = " +(int)weight+ " KM");

	}

	public static enum RelTypes implements RelationshipType {
	ROUTE
	}



	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	// Registers a shutdown hook for the Neo4j instance so that it
	// shuts down nicely when the VM exits (even if you "Ctrl-C" the
	// running example before it's completed)
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

The output of the above search program is

	SOURCE: BANGALORE CY JN DESTINATION: HUBLI JN

	Route for least number of Stops
	BANGALORE CY JN -> YESVANTPUR JN -> DHARMAVARAM JN -> ANANTAPUR -> GUNTAKAL JN -> BELLARY JN -> HOSPET JN -> KOPPAL -> GADAG JN -> HUBLI JN ->

	Distance = 541 KM

	Route for minimum distance
	BANGALORE CY JN -> YESVANTPUR JN -> TUMKUR -> AMMASANDRA -> TIPTUR -> ARSIKERE JN -> KADUR -> BIRUR JN -> DAVANGERE -> HARIHAR -> RANIBENNUR -> HAVERI -> HUBLI JN ->
	Distance = 469 KM

view raw gistfile1.txt hosted with ❤ by GitHub

3. Facebook Graph Search

Facebook Graph Search is released. It provides search based on your friends connections, likes and recommendations. So I could ask it for "Suggest me Indian Vegetarian restaurants in and around South London". There is a wonderful article on how to build this with Neo4j at http://jimwebber.org/2013/02/neo4j-facebook-graphsearch-for-the-rest-of-us/

I implemented the code based on the above design. First build the Graph <

	package com.raj.socialgraph;

	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.Node;
	import org.neo4j.graphdb.RelationshipType;
	import org.neo4j.graphdb.Transaction;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;

	public class SocialGraph {

	public static final String DB_PATH="c://apps//neo4j-1.8.2//socialgraph";
	public static GraphDatabaseService graphDb = null;

	/**
	* @param args
	*/
	public static void main(String[] args) {
	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );
	Transaction tx = graphDb.beginTx();
	loadData();
	tx.success();
	tx.finish();
	System.out.println("Created Social Graph!!");
	}


	public static void loadData() {
	Node jim = graphDb.createNode();
	jim.setProperty("name", "Jim");
	graphDb.index().forNodes("name").add(jim, "name", "Jim");

	Node kath = graphDb.createNode();
	kath.setProperty("name", "Kath");
	graphDb.index().forNodes("name").add(kath, "name", "Kath");

	Node martin = graphDb.createNode();
	martin.setProperty("name", "Martin");
	graphDb.index().forNodes("name").add(martin, "name", "Martin");

	Node simon = graphDb.createNode();
	simon.setProperty("name", "Simon");
	graphDb.index().forNodes("name").add(simon, "name", "Simon");

	jim.createRelationshipTo(kath, RelTypes.FRIEND);
	jim.createRelationshipTo(martin, RelTypes.FRIEND);
	jim.createRelationshipTo(simon, RelTypes.FRIEND);
	martin.createRelationshipTo(simon, RelTypes.FRIEND);

	Node tandooriNights = graphDb.createNode();
	tandooriNights.setProperty("restaurant", "Tandoori Nights");
	graphDb.index().forNodes("restaurant").add(tandooriNights, "name", "Tandoori Nights");

	Node indianMischief = graphDb.createNode();
	indianMischief.setProperty("restaurant", "Indian Mischief");
	graphDb.index().forNodes("restaurant").add(indianMischief, "name", "Indian Mischief");

	Node babur = graphDb.createNode();
	babur.setProperty("restaurant", "Babur");
	graphDb.index().forNodes("restaurant").add(babur, "name", "Babur");

	Node indian = graphDb.createNode();
	indian.setProperty("category", "Indian");
	graphDb.index().forNodes("category").add(indian, "name", "Indian");

	Node vegetarian = graphDb.createNode();
	vegetarian.setProperty("category", "Vegetarian");
	graphDb.index().forNodes("category").add(vegetarian, "name", "Vegetarian");

	tandooriNights.createRelationshipTo(indian, RelTypes.CUISINE);
	indianMischief.createRelationshipTo(indian, RelTypes.CUISINE);
	babur.createRelationshipTo(indian, RelTypes.CUISINE);
	indianMischief.createRelationshipTo(vegetarian, RelTypes.CUISINE);

	Node eastDulwich = graphDb.createNode();
	eastDulwich.setProperty("neighbourhood", "East Dulwich");
	graphDb.index().forNodes("neighbourhood").add(eastDulwich, "name", "East Dulwich");

	Node forestHill = graphDb.createNode();
	forestHill.setProperty("neighbourhood", "Forest Hill");
	graphDb.index().forNodes("neighbourhood").add(forestHill, "name", "Forest Hill");

	tandooriNights.createRelationshipTo(eastDulwich, RelTypes.IN);
	indianMischief.createRelationshipTo(eastDulwich, RelTypes.IN);
	babur.createRelationshipTo(forestHill, RelTypes.IN);

	Node southwark = graphDb.createNode();
	southwark.setProperty("borough", "Southwark");
	graphDb.index().forNodes("borough").add(southwark, "name", "Southwark");

	Node southLondon = graphDb.createNode();
	southLondon.setProperty("area", "South London");
	graphDb.index().forNodes("area").add(southLondon, "name", "South London");

	Node london = graphDb.createNode();
	london.setProperty("city", "London");
	graphDb.index().forNodes("city").add(london, "name", "London");

	eastDulwich.createRelationshipTo(southwark, RelTypes.IN);
	forestHill.createRelationshipTo(southwark, RelTypes.IN);
	southwark.createRelationshipTo(southLondon, RelTypes.IN);
	southLondon.createRelationshipTo(london, RelTypes.IN);

	jim.createRelationshipTo(tandooriNights, RelTypes.LIKES);
	kath.createRelationshipTo(tandooriNights, RelTypes.LIKES);
	martin.createRelationshipTo(babur, RelTypes.LIKES);
	simon.createRelationshipTo(babur, RelTypes.LIKES);
	}



	public static enum RelTypes implements RelationshipType {
	FRIEND,
	CUISINE,
	LIKES,
	IN
	}



	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

Next run search on restaurants

	package com.raj.socialgraph;

	import org.neo4j.cypher.ExecutionEngine;
	import org.neo4j.cypher.ExecutionResult;
	import org.neo4j.graphdb.GraphDatabaseService;
	import org.neo4j.graphdb.factory.GraphDatabaseFactory;
	import org.neo4j.kernel.impl.util.StringLogger;

	import scala.collection.immutable.Map;

	public class Recommender {


	public static final String DB_PATH="c://apps//neo4j-1.8.2//socialgraph";
	public static GraphDatabaseService graphDb = null;

	/**
	* @param args
	*/
	public static void main(String[] args) {
	graphDb = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
	registerShutdownHook( graphDb );
	ExecutionEngine engine = new ExecutionEngine(graphDb, StringLogger.SYSTEM );
	String query = new StringBuffer("START jim = node:name(name='Jim'),")
	.append(" southwark = node:borough(name='Southwark'),")
	.append(" indian = node:category(name='Indian')")
	.append(" MATCH jim-[:FRIEND]->friend-[:LIKES]->restaurant-[:IN]->()-[:IN]->southwark,")
	.append(" restaurant-[:CUISINE]->indian,")
	.append(" jim-[:LIKES]->myrestaurant")
	.append(" WHERE restaurant.restaurant <> myrestaurant.restaurant")
	.append(" RETURN distinct restaurant.restaurant;").toString();
	ExecutionResult result = engine.execute( query );
	Map<String, Object> map = result.next();
	System.out.println( map.get("restaurant.restaurant") );

	}

	private static void registerShutdownHook( final GraphDatabaseService graphDb )
	{
	Runtime.getRuntime().addShutdownHook( new Thread()
	{
	@Override
	public void run()
	{
	graphDb.shutdown();
	}
	} );
	}


	}

view raw gistfile1.java hosted with ❤ by GitHub

High Availability

Neo4j enterprise edition provides high availability in the form of replication and shard caching. I tried this on a 63 Million Node relationships with a cluster of 3 nodes. Planning to write up in next series....

Sunday, March 3, 2013

Real-Time Data Analysis using Twitter Stream

Experiment

Twitter processes half a billion tweets per day. The size of a tweet is max 140 characters. For experimentation purpose, Twitter provides these tweets to the public. Initially they were providing it through REST API and then moved onto OAuth. Twitter Streaming API makes this possible, and provides real-time streaming tweets at 1% of the Twitter's load. So that means, on an average Twitter receives 5787 ( 500000000 Tweets / (24 Hours * 60 Mins * 60 Secs) ) Tweets per second and the Streaming API sends us 58 Tweets per second. And this data is arriving constantly, so we need a mechanism to store 58 tweets every second and run real-time analytics on them. Even though each Tweet is 140 characters or 280 Bytes ( Char is 2 bytes ), the Streaming-API sends us a lot of information for each Tweet (1 Tweet = 4 KB). This information is sent in the JSON format.

The Twitter data provides a very valuable tool in the field of marketing. Vendors can do sentiment analysis using Tweets for a specific hashTag. So if Samsung wants to know how content people are about their products, they can do so with the Tweet data. As a result a lot of NLP (Natural Language Processing) field researches have started. Apart from this, we can do a lot of machine learning tasks on these Tweets.

As part of this experiment I implemented a Consumer to read the stream of JSON tweets and persist in MongoDB. Since its a write-heavy application, I load-balanced (Sharded) my MongoDB. This application keeps running forever. Now the data starts filling up my MongoDB clusters. To keep the storage minimum, I extracted and stored only TweetID, Tweeter Name, Actual Tweet, the Source of the Tweet ( eg. twitter.com, facebook.com, blackberry, etc). Then I setup a MongoDB incremental Map-Reduce job to run every 10 minutes. This job gets the statistics of unique sources and their counts. From this I generated the top 10 statistics and create chart using JFreeChart.

Architectural Overview

Execution

Setup Twitter Account

Goto https://dev.twitter.com/apps and click "Create a new application".

Fill up all mandatory information and submit the application

Goto the tab "OAuth Tool" and note down the Consumer Key and Consumer Secret.

Run the following program by changing the consumer key and consumer secret

	package com.raj.tweets;

	import java.io.BufferedReader;
	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.util.logging.Level;
	import java.util.logging.Logger;

	import twitter4j.Status;
	import twitter4j.Twitter;
	import twitter4j.TwitterException;
	import twitter4j.TwitterFactory;
	import twitter4j.User;
	import twitter4j.auth.AccessToken;
	import twitter4j.auth.RequestToken;

	public class TwitterOAuth {

	public static void main(String args[])
	{
	try
	{
	// The factory instance is re-useable and thread safe.
	Twitter twitter = new TwitterFactory().getInstance();
	twitter.setOAuthConsumer("<consumer-key>", "<consumer-secret>");

	RequestToken requestToken = twitter.getOAuthRequestToken();
	AccessToken accessToken = null;
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	while (null == accessToken)
	{
	System.out.println("Open the following URL and grant access to your account:");
	System.out.println(requestToken.getAuthorizationURL());
	System.out.print("Enter the PIN(if aviailable) or just hit enter.[PIN]:");
	String pin = null;
	try
	{
	pin = br.readLine();
	} catch (IOException ex)
	{
	Logger.getLogger(TwitterOAuth.class.getName()).log(Level.SEVERE, null, ex);
	}
	try
	{
	if (pin.length() > 0)
	{
	accessToken = twitter.getOAuthAccessToken(requestToken, pin);
	} else
	{
	accessToken = twitter.getOAuthAccessToken();
	}
	} catch (TwitterException te)
	{
	if (401 == te.getStatusCode())
	{
	System.out.println("Unable to get the access token.");
	} else
	{
	te.printStackTrace();
	}
	}
	}
	//persist to the accessToken for future reference.
	storeAccessToken(twitter.verifyCredentials(), accessToken);
	Status status = twitter.updateStatus("Done setup..");
	System.out.println("Successfully updated the status to [" + status.getText() + "].");
	System.exit(0);
	} catch (TwitterException ex)
	{
	Logger.getLogger(TwitterOAuth.class.getName()).log(Level.SEVERE, null, ex);
	}
	}

	private static void storeAccessToken(User user, AccessToken accessToken)
	{
	System.out.println(user.getScreenName());
	}
	}

view raw gistfile1.java hosted with ❤ by GitHub

Follow the instructions of the program to generate the Access Token and Access Token Secret.

It can later be obtained from the "OAuth Tool" tab.

Setup MongoDB

MongoDB provides sharding capability on database/collections. So I setup a simple MongoDB sharding setup with 2 Laptops - 1 TB, 4 GB RAM, Toshiba Windows 7

System-1 : 192.168.1.100
System-2 : 192.168.1.101

MongoDB 2.2.3 is installed in both the laptops at c:\\apps\mongodb.

Create directories in System-1
c:\\apps\mongodb\data1
c:\\apps\mongodb\data2
c:\\apps\mongodb\data3
c:\\apps\mongodb\conf

On System1
c:\apps\mongodb\bin> mongod --shardsvr --dbpath c:\apps\mongodb\data1 --port 27020

On System2
c:\apps\mongodb\bin> mongod --shardsvr --dbpath c:\apps\mongodb\data1 --port 27020

On System1
c:\apps\mongodb\bin> mongod --shardsvr --dbpath c:\apps\mongodb\data2 --port 27021

c:\apps\mongodb\bin> mongod --configsvr --dbpath c:\apps\mongodb\conf --port 27022

c:\apps\mongodb\bin> mongos --configsvr --configdb 192.168.1.100:27020,192.168.1.100:27021,192.168.1.101:27020 --port 27017

c:\apps\mongodb\bin> mongo 192.168.1.100:27017

mongos> use admin
switched to admin
mongos> db.runCommand({addShard:"192.168.1.100:27020"});
{"shardAdded": "shard0000", "ok": 1}
mongos> db.runCommand({addShard:"192.168.1.100:27021"});
{"shardAdded": "shard0001", "ok": 1}
mongos> db.runCommand({addShard:"192.168.1.101:27020"});
{"shardAdded": "shard0002", "ok": 1}
mongos> db.runCommand({listShards: 1})
{
 "shards" : [
   {
     "_id"  : "shard0000",
     "host" : "192.168.1.100:27020"
   },
   {
     "_id"  : "shard0001",
     "host" : "192.168.1.100:27021"
   },
   {
     "_id"  : "shard0002",
     "host" : "192.168.1.101:27020"
   }
 ]
 "ok" : 1
}

mongos> use twitterdb
switched to db twitterdb

mongos> db.createCollection("tweets")
{"ok" : 1}

mongos> use admin
switched to db admin

mongos> db.runCommand({enableSharding: "twitterdb"})
{ "ok" : 1}

mongos> db.runCommand({shardCollection: "twitterdb.tweets", key: {id_str: 1}})
{"collectionSharded" : "twitterdb.tweets", "ok" : 1}

mongos> use twitterdb
switched to db twitterdb

mongos> db.tweets.find().count()
0

Running the Application

So we have just finished setting up the Shards and the database setup.

RUN The below Twitter Stream Application below (please change the appropriate values as per your settings). Data Starts pumping into MongoDB. Don't forget to stop the application when you are done, else twitter stream consumes network bandwidth and the mongodb storage will shoot up.

	package com.raj.tweets;

	import twitter4j.StallWarning;
	import twitter4j.Status;
	import twitter4j.StatusDeletionNotice;
	import twitter4j.StatusListener;
	import twitter4j.TwitterStream;
	import twitter4j.TwitterStreamFactory;
	import twitter4j.conf.ConfigurationBuilder;
	import twitter4j.json.DataObjectFactory;

	import com.mongodb.BasicDBObject;
	import com.mongodb.DB;
	import com.mongodb.DBCollection;
	import com.mongodb.DBObject;
	import com.mongodb.Mongo;
	import com.mongodb.util.JSON;

	public class TwitterStreaming {

	public static void main(String[] args) {
	try
	{
	Mongo m = new Mongo("192.168.1.100", 27017);
	DB db = m.getDB("twitterdb");

	final DBCollection coll = db.getCollection("tweets");

	ConfigurationBuilder cb = new ConfigurationBuilder();
	cb.setDebugEnabled(true)
	.setOAuthConsumerKey("<consumerKey>")
	.setOAuthConsumerSecret("<consumerSecret>")
	.setOAuthAccessToken("<accessToken>")
	.setOAuthAccessTokenSecret("<accessTokenSecret>");

	StatusListener listener = new StatusListener(){
	int count = 0;
	public void onStatus(Status status) {

	DBObject dbObj = new BasicDBObject();
	dbObj.put("id_str", status.getId());
	dbObj.put("name", status.getUser().getName());
	dbObj.put("text", status.getText());
	dbObj.put("source", status.getSource());
	coll.insert(dbObj);
	System.out.println(++count);
	}
	public void onDeletionNotice(StatusDeletionNotice statusDeletionNotice) {}
	public void onTrackLimitationNotice(int numberOfLimitedStatuses) {}
	public void onException(Exception ex) {
	ex.printStackTrace();
	}
	@Override
	public void onScrubGeo(long arg0, long arg1) {
	// TODO Auto-generated method stub

	}
	@Override
	public void onStallWarning(StallWarning arg0) {
	// TODO Auto-generated method stub

	}
	};

	TwitterStream twitterStream = new TwitterStreamFactory(cb.build()).getInstance();
	twitterStream.addListener(listener);
	twitterStream.sample();

	}catch(Exception e) {
	e.printStackTrace();
	}
	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

Keep a tab on the filesystem data:-
System:1
c:\apps\mongodb\data1
c:\apps\mongodb\data2

System:2
c:\apps\mongodb\data1

The data files grows continously. Verify the counts of the tweets in the database.

mongos> db.tweets.find().count()
25043

So 25,000 tweets accumulated in 10 mins or 40 tweets per second Find out how many people tweeted in this 10 minutes using web

mongos> db.tweets.find({"source" : "web"}).count()
4365

Now RUN the below MapReduce Job to run every 10 minutes and aggregate the results and generate the reports as Pie-Chart. These charts will be stored in your local file system.

	package com.raj.tweets;

	import java.text.DateFormat;
	import java.text.SimpleDateFormat;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Date;
	import java.util.List;
	import java.util.Map;
	import java.util.TreeMap;

	import org.bson.types.ObjectId;

	import com.mongodb.BasicDBObject;
	import com.mongodb.DB;
	import com.mongodb.DBCollection;
	import com.mongodb.DBObject;
	import com.mongodb.MapReduceCommand;
	import com.mongodb.MapReduceOutput;
	import com.mongodb.Mongo;
	import com.mongodb.QueryBuilder;

	public class TwitterMapReduce {

	private Mongo mongo;
	private DB db;
	private MapReduceCommand cmd1;
	private MapReduceCommand cmd2;
	private DBCollection inputCollection;
	private String map;
	private String reduce;
	private String outputCollection;
	private Map<String, Double> result = new TreeMap<String, Double>();
	private Map<Double, List<String>> top10 = new TreeMap<Double, List<String>>();
	private String lastKey = null;

	public TwitterMapReduce() throws Exception {
	mongo = new Mongo("192.168.1.100", 27017);
	db = mongo.getDB("twitterdb");
	inputCollection = db.getCollection("tweets");
	outputCollection = "tweetstat";
	map = " function() { " +
	" emit(this.source, {count: 1}) " +
	" }";

	reduce = "function(key, values) { " +
	"var sum = 0; " +
	"values.forEach(function(v) { " +
	"sum = sum + v['count'] "+
	"}); " +
	"return {count: sum}} ";

	cmd1 = new MapReduceCommand(inputCollection, map, reduce, outputCollection, MapReduceCommand.OutputType.INLINE, null);
	}

	public void run() {

	System.out.println("Running map Reduce: Last Key = " +lastKey);
	DBObject obj = new BasicDBObject();
	obj.put("_id", -1);

	MapReduceOutput out = null;
	if( lastKey == null ) {
	out = inputCollection.mapReduce( cmd1 );
	lastKey = inputCollection.find().sort(obj).next().get("_id").toString();
	} else {
	QueryBuilder qb = new QueryBuilder();
	qb.put("_id").greaterThan(new ObjectId(lastKey));
	cmd2 = new MapReduceCommand(inputCollection, map, reduce,
	outputCollection, MapReduceCommand.OutputType.INLINE, qb.get());
	out = inputCollection.mapReduce( cmd2 );
	lastKey = inputCollection.find().sort(obj).next().get("_id").toString();
	}


	result = new TreeMap<String, Double>();

	double total = 0;
	double count = 0;
	DBObject value = null;
	String name = null;
	String trimmed = null;
	for (DBObject o : out.results()) {
	value = (DBObject)o.get("value");
	count = (Double)value.get("count");
	name = (String)o.get("_id");
	trimmed = trim( name );
	total += count;
	if( result.containsKey(trimmed)) {
	result.put(trimmed, count + result.get(trimmed));
	} else {
	result.put(trimmed, count);
	}
	}


	top10 = new TreeMap<Double, List<String>>(Collections.reverseOrder());
	for( String s: result.keySet() ) {
	double val = result.get( s );
	if( top10.containsKey(val) ) {
	top10.get(val).add(s);
	} else {
	List<String> list = new ArrayList<String>();
	list.add(s);
	top10.put(val, list);
	}
	}
	}


	/**
	* @param args
	*/
	public static void main(String[] args) throws Exception {

	TwitterMapReduce app = new TwitterMapReduce();
	try {
	while( true ) {
	DateFormat formatter = new SimpleDateFormat("dd-MMM-yyyy-hh_mm_ss");
	String today = formatter.format(new Date());
	app.run();
	if( !app.top10.isEmpty() ) {
	new TwitterChart("Twitter Stream", today, app.top10);
	}
	Thread.sleep(10006010); //10 minutes
	}
	}catch(Exception e) {
	e.printStackTrace();
	}
	}

	public static String trim(String s) {
	if( s.indexOf("href") != -1) {
	s = s.substring(s.indexOf("href"), s.indexOf("rel") - 2);
	if( s.indexOf("http://") != -1 ) {
	s = s.substring(s.indexOf("http://") + 7);
	} else if( s.indexOf("https://") != -1) {
	s = s.substring(s.indexOf("https://") + 8);
	}

	if( s.indexOf("/") != -1 ) {
	s = s.substring(0, s.indexOf("/"));
	}
	}

	return s;
	}


	}

view raw gistfile1.java hosted with ❤ by GitHub

Chart Utility

	package com.raj.tweets;

	import java.io.File;
	import java.util.List;
	import java.util.Map;

	import org.jfree.chart.ChartFactory;
	import org.jfree.chart.ChartUtilities;
	import org.jfree.chart.JFreeChart;
	import org.jfree.chart.plot.PiePlot3D;
	import org.jfree.data.general.DefaultPieDataset;
	import org.jfree.data.general.PieDataset;
	import org.jfree.util.Rotation;

	public class TwitterChart {

	private static final long serialVersionUID = 1L;

	public TwitterChart(String applicationTitle, String chartTitle, Map<Double, List<String>> map) throws Exception {
	// This will create the dataset
	PieDataset dataset = createDataset( map );
	// based on the dataset we create the chart
	JFreeChart chart = createChart(dataset, chartTitle);
	ChartUtilities.saveChartAsJPEG(new File("c:\\project\\Twitter\\" +chartTitle+ ".jpg"), chart, 500, 500);
	}


	/**
	* Creates a sample dataset
	*/

	private PieDataset createDataset( Map<Double, List<String>> top10 ) {
	DefaultPieDataset result = new DefaultPieDataset();

	System.out.println("**RESULTS*");
	int count = 0;
	for( double val: top10.keySet() ) {
	result.setValue(top10.get(val).toString(), val);
	count++;
	if( count == 7 ) {
	break;
	}
	}
	return result;

	}


	/**
	* Creates a chart
	*/

	private JFreeChart createChart(PieDataset dataset, String title) {

	JFreeChart chart = ChartFactory.createPieChart3D(title, // chart title
	dataset, // data
	true, // include legend
	true,
	false);

	PiePlot3D plot = (PiePlot3D) chart.getPlot();
	plot.setStartAngle(290);
	plot.setDirection(Rotation.CLOCKWISE);
	plot.setForegroundAlpha(0.5f);
	return chart;

	}

	}

view raw gistfile1.java hosted with ❤ by GitHub

Download

The file can be downloaded here containing the entire project.

Break the CODE!!!

Sunday, March 31, 2013

Neo4j Graph Case Study - Facebook & Trip Planner

NoSQL Graph Database - Neo4j

Applications of Neo4j

1. Facebook friend connect

2. Railway Trip Planner

3. Facebook Graph Search

High Availability

Sunday, March 3, 2013

Real-Time Data Analysis using Twitter Stream

Experiment

Execution

Setup Twitter Account

Setup MongoDB

Running the Application

Download

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