MongoDB Scratch pad

Main.java

/**
 * Example code for MongoDB CRUD
 * and commands.
 * 
 */
package com.tengen.demo;

import com.mongodb.*;
import com.mongodb.util.*;
import com.mongodb.gridfs.*;

import java.io.*;
import java.util.*;
import java.util.regex.*;


/**
 * @author danielroberts at 10gen
 *
 */
public class Main {

	
	/*
	 * Create connection to MongoDB
	 */
	private Mongo m = null;
	

	/*
	 * static variables
	 */
	private static int NUM_NODES = 2; //Number of nodes that should be written to.
	private static int W_TIMEOUT = 5000; //Number of milliseconds for timeout exception.
	
	/*
	 * Constructor
	 */
	public Main() throws Exception
	{
		 List<ServerAddress> address = new ArrayList<ServerAddress>();
		 address.add( new ServerAddress( "127.0.0.1" , 27017 ) );
		 //address.add( new ServerAddress( "127.0.0.1" , 27018 ) );
		 //address.add( new ServerAddress( "127.0.0.1" , 27019 ) );
		 //address.add( new ServerAddress( "127.0.0.1" , 20000 ) );
		 
		 m = new Mongo(address);
		 
		 m.setReadPreference(ReadPreference.SECONDARY);
		 
		 
	}
	
	/*
	 * Insert data in to MongoDB
	 * User the Mongo object to get hold of the database and collection
	 * to write to.  
	 */
	public void insert() throws Exception
	{

		//Starting insert
		System.out.println("Start insert();");
		//Get database.
		DB db = m.getDB("test");
	
		
		//Get the collection
		DBCollection col = db.getCollection("stuff");
		//How many documents are their in the collection.
		System.out.println("Collection count():"+col.getCount());
				
		//Create a WriteConcern to ensure that data it written to more that 1 node before returning.
		//WriteConcern wc = new WriteConcern(NUM_NODES,W_TIMEOUT);
		//WriteConcern wc = new WriteConcern();
		WriteConcern wc = WriteConcern.NONE;
	
		
		//Insert data in to the collection.
		col.insert(createDocument("Daniel","Roberts","Oracle","200 Aldersgate, London"),wc);
		col.insert(createDocument("Chris","Harris","10gen","200 Aldersgate, London"),wc);
		col.insert(createDocument("Gerry","Treacy","10gen","123 Guiness Street, Dublin"),wc);
		col.insert(createDocument("Alvin","Richards","10gen","555 University, Palo Alto"),wc);
		

		
	}
	
	//Create BasicDBObject to insert into MongoDB.
	private BasicDBObject createDocument(String fn, String ln, String company, String address)
	{
		BasicDBObject dbo = new BasicDBObject();	
		dbo.put("fn",fn);
		dbo.put("ln",ln);
		dbo.put("company",company);		
		dbo.put("address",address);
		return dbo;
	}
	
	public void insertUUID() throws Exception 
	{
		DB db = m.getDB("test");
		//Get the collection
		DBCollection col = db.getCollection("uuuu");
		BasicDBObject dbo = new BasicDBObject();	
		dbo.put("uuid", UUID.randomUUID());
		col.insert(dbo);
				
	}
	
	
	/*
	 * Qurey data from MongoDB
	 */
	public void query() throws Exception
	{
		this.printAddresses();
		//Get hold of the test database from the Mongo object.
		DB db = m.getDB("test");
		
		//Find all the all the collections in the test database.
		//show dbs from mongo shell
		Set<String> colls = db.getCollectionNames();
	

		for (String s : colls) 
		{
		    System.out.println(s);
		}
		
		//Get a hold of the stuff collection in order to do some queries.
		DBCollection col = db.getCollection("stuff");
		
		//Queries are created using BasicDBObject
		BasicDBObject q = new BasicDBObject();
		//Create a query using a regular expression. This is using standard java.util.regex.*
		q.put("fn", Pattern.compile("^D"));  //Regex
		//{fn: /^D/}
		//Return the JSON query string.
		System.out.println("Query Object:"+q.toString());
		
		//Execute the query and get a DBCursor object back to iterate over.
		//(DBObject)JSON.parse("{a:1,b:2}")
		//DBCursor cur = col.find((DBObject)JSON.parse("{a:1,b:2}"));
		
		DBCursor cur = col.find(q);
		
		System.out.println("Cursor length,count:"+cur.length()+":"+cur.size());
		Iterator<DBObject> i = cur.iterator();
		while(i.hasNext())
		{
				System.out.println(i.next().toString());
		}	
		
	}
	
	
	/**
	 * 
	 * */
	 public void queryTest() throws Exception {
		 DB db = m.getDB("mtest");
		 DBCollection col = db.getCollection("mbucket");
		 
		 //Query {company:'tengen',user:'dmr'}
		 DBObject query = (DBObject)JSON.parse("{company:'tengen',user:'dmr'}");
		 
		 
		 //Projection {_id:0, conversation:1, msgs : {$slice:-1}}
		 DBObject projection = (DBObject)JSON.parse("{_id:0, conversation:1, msgs : {$slice:-1}}");
				 
		 DBCursor cur = col.find(query, projection);
		 
		 //Sort {'msgs.message.ts':1}
		 cur.sort((DBObject)JSON.parse("{'lastmessage':-1}"));
		 
		 HashMap<String, String> lastMsgs = new HashMap<String, String>(5);
		 
		 Iterator<DBObject> i = cur.iterator();
		 while(i.hasNext())
		{
			BasicDBObject dbo = (BasicDBObject)i.next();
			BasicDBList dbl = (BasicDBList)dbo.get("msgs");
			BasicDBObject msg = (BasicDBObject)dbl.get(0);
		
			String conv = dbo.get("conversation").toString();
			String l_msg = msg.get("message").toString();
			
			if(!lastMsgs.containsKey(conv))
			{
				lastMsgs.put(conv, l_msg);
			}
		}
		 
		 System.out.println(lastMsgs.toString());
		 cur.close();
	 }
	
	/*
	 * Update data in MongoDB.
	 */
	public void update() throws Exception
	{
		//Get hold of the test database from the Mongo object.
		DB db = m.getDB("test");
		//Get hold of the collection from the database.
		DBCollection col = db.getCollection("blah");
		
		//Build the update query again with the BasicDBObject.
		BasicDBObject query = new BasicDBObject();
		query.put("fn", "Daniel");
		//Use the $set modifier to update documents.
		BasicDBObject update = new BasicDBObject("$set", new BasicDBObject("address","400 Aldersgate"));
		System.out.println(update.toString());
		col.update(query, update,false,true);
		CommandResult cr = db.getLastError();
		System.out.println("getLastError"+cr.toString());
	}
	
	/*
	 * Run a command on the database.
	 * Examples: isMaster, dbstats, listCommands,connPoolStats, replSetGetStatus
	 */
	public void runCommand() throws Exception
	{
		System.out.println("runCommand()");
		/*
		 * Get hold of the admin database, not all command require the admin database.
		 * See db.listCommands() from sell for more information.
		 */
		DB db = m.getDB("admin");
		/*
		 * Commands are issued by building JSON through the BasicDBOBject, same as for CRUD.
		 * console -> db.runCommand({'replSetGetStatus',1}); = rs.status(); = same as following code..
		 */
		BasicDBObject dbCommand = new BasicDBObject("replSetGetStatus","1");
		CommandResult cr = db.command(dbCommand);
		System.out.println(cr.toString());
	}
	
	
	/**
	 * print addresses
	 */
	private void printAddresses()
	{
		List<ServerAddress> addrs = m.getAllAddress();
		Iterator<ServerAddress> i = addrs.iterator();
		while(i.hasNext())
		{
			System.out.println("Addr: "+i.next());
		}
	}
	
	
	public void insertJSON() throws Exception
	{
		//Starting insert
				System.out.println("Start insert(JSON);");
				//Get database.
				DB db = m.getDB("test");
				//Get the collection
				DBCollection col = db.getCollection("uuuu");
				//How many documents are their in the collection.
				col.save((DBObject)JSON.parse("{a:'d376cc14-af33-4f6d-978b-4ab4af6079e0',b:2}"));			
				
	}
	
	
	
	public void insertGridFS() throws Exception
	{
		// /Users/danielroberts/Downloads/Daniel Roberts.jpg
		String newFileName = "dmr";
		File imageFile = new File("/Users/danielroberts/Downloads/Daniel Roberts.jpg");
		DB db = m.getDB("test"); 
		GridFS gfsPhoto = new GridFS(db,"photos");
		GridFSInputFile gfsFile = gfsPhoto.createFile(imageFile);
		
		gfsFile.setContentType("blah/jpg");
		gfsFile.setFilename(newFileName);
		
		gfsFile.setId("abc1234");
		
		BasicDBObject meta = new BasicDBObject();	
		meta.put("fn","Daniel");
		gfsFile.setMetaData(meta);
		
		//save
		gfsFile.save();
		//End
		System.out.println("insert GridFS finished.");
	}
	
	public void getGridFS() throws Exception
	{
		DB db = m.getDB("test");
		String newFileName = "dmr";
		GridFS gfsPhoto = new GridFS(db, "photos");
		GridFSDBFile imageForOutput = gfsPhoto.findOne(newFileName);
		
		System.out.println(imageForOutput);
		imageForOutput.writeTo("/Users/danielroberts/Downloads/"+newFileName);
	}
	
	public void insert(DBObject dbo) throws Exception
	{
		DB db = m.getDB("test");
		//Get the collection
		DBCollection col = db.getCollection("bar");
		col.insert(dbo);
	}
	
	public DBObject build() throws Exception
	{
		DBObject dbo = BasicDBObjectBuilder.start()
				.add("fn", "Daniel")
				.add("ln", "Roberts")
				.add("data",BasicDBObjectBuilder.start().add("a", 1)
						.add("b",2).get())
				.add("more","data").get();
		
		System.out.println(dbo.toString());
		
		return dbo;
				
	}
	
	
	public void fAndM() throws Exception
	{
		DB db = m.getDB("test");
		//Get the collection
		DBCollection col = db.getCollection("bar");
		DBObject doc = col.findAndModify(	new BasicDBObject(), 	//query
											null, 	//fields
											null, 					//sort
											true, 					//boolean remove
											null, 					//update obj
											false, 					//return new
											false);					//Upsert */
											
		System.out.println("fAndM:"+doc);
	}
	
	
	
	/**
	 *
	 * example queries and updates.
	 * db.stuff.update({"names.language":"en"}, {"$set" : { "names.$.state" : "London"}} ); 
	 * db.stuff.update({fn:'Daniel'},{$set : {age:21}}); //set adds key if it doesn't exist.
	 * db.stuff.find({age : {$lte:38}});  //$lt => <,$gt => >,$gte => =<, $ne => !=
	 * db.stuff.find({fn: /D/});  // regex
	 */
	public static void main(String[] args)  throws Exception
	{
		System.out.println("Starting...");
		Main main = new Main();
		
		/*while(true)
		{
			try
			{
				main.insert();
				
			}
			catch(Exception e)
			{
				System.out.println("Exeception "+e.getMessage());
				e.printStackTrace();
			}
			finally
			{
				Thread.sleep(2000);
			}
			
		}//*/

		//main.fAndM();
		main.insertGridFS();
		//main.getGridFS();
		//main.insertJSON();
		//main.query();
		//main.update();
		//main.runCommand();
		//main.insertUUID();
		
		/*/UUID u1 = UUID.randomUUID();
		System.out.println(u1.toString());
		//System.out.println(UUID.fromString("Daniel"));
		System.out.println(UUID.nameUUIDFromBytes("Daniel".getBytes()));//*/
		
		
		//main.insert(main.build());
		
		//main.queryTest();
		
		//System.out.println("End.");

	}
}