1. Sadalage & Fowler (Amazon)
Graphdatabases.com (free!)

2. From Fowler

3. By Nathan Hurst

4. From Robinson

5. From Fowler

6. From Robinson

7. From Fowler

8. From Robinson

9. From Wikipedia

10. From Fowler

11. From Robinson

16. function map() {
// get content of the current document
var cnt = this.content;
// split the content into an array of words using a regular expression
var words = cnt.match(/\w+/g);
// if there are no words, return
if (words == null) {
return; }
// for each word, output {word, count} pair
for (var i = 0; i < words.length; i++) {
emit({ word:words[i] }, { count:1 });
From Isuru Suriarachchi's Blog

17. Format of the documents in our collection:
{ "_id" : ObjectId("519f6c1f44ae9aea a"), "pageId" : "page1",
"content" : "your page1 content" }
From Isuru Suriarachchi's Blog

18. function reduce(key, counts) {
var cnt = 0;
// loop through call count values
for (var i = 0; i < counts.length; i++) {
// add current count to total
cnt = cnt + counts[i].count; }
// return total count
return { count:cnt };
From Isuru Suriarachchi's Blog

19. From Isuru Suriarachchi's Blog
public class WordCount {
public static void main(String[] args) {
try {
// create a MongoClient by connecting to the
// MongoDB instance in localhost
MongoClient mongoClient =
new MongoClient("localhost", 27017);
// access the db named "sample"
DB db = mongoClient.getDB("sample");
// access the input collection
DBCollection collection = db.getCollection("book");
// read Map file
String map = readFile("wc_map.js");
// read Reduce file
String reduce = readFile("wc_reduce.js");
// execute MapReduce on the input collection and
// direct the result to "wordcounts" collection
collection.mapReduce(map, reduce, "wordcounts",
MapReduceCommand.OutputType.REPLACE, null);
} catch (Exception e) {
e.printStackTrace(); }
From Isuru Suriarachchi's Blog

20. From Isuru Suriarachchi's Blog
/**
* Reads the specified file from classpath */
private static String readFile(String fileName)
throws IOException {
// get the input stream
InputStream fileStream =
WordCount.class.getResourceAsStream("/" + fileName);
// create a buffer with some default size
byte[] buffer = new byte[8192];
// read the stream into the buffer
int size = fileStream.read(buffer);
// create a string for the needed size and return
return new String(buffer, 0, size); }
From Isuru Suriarachchi's Blog