Please see Apache hadoop

Why amazon EC2(Elastic Cloud Computing)?

Amazon cloud  provides hardware and software resources at low cost. The charge is based on usage. In compared to its real software and hardware cost, this is marginally low.

In amazon there are software instance available in ready to use mode. The only thing we have to do is create an account in amazon cloud. Select the instance that we are going to use. Start the instance. The payment is based on how many instances we are using.

Why Hadoop

Hadoop helps to configure multiple processing nodes as a single entity. And we can share a complex problem over this frame work.  So this integrates number of processing nodes together.

In Hadoop the main processing node is called name node and all other slave nodes are called data node. Each name node and data node have their own storage area for storing processing data.

Hadoop will work on single node cluster mode and multi-node cluster. All is configured in hadoop configuration files located in hadoop’s configuration folder.

How to use hadoop in EC2

Follow the following steps

1. Register an account in Amazon EC2
2. Select a hadoop installed EC2 Image
3. Make five instances from the selected Image.
4. You can use putty to connect to all these instances.
5. By using some FTP client(WinSCP) you can transfer files to these instances

Here is the one best available tutorial to configure hadoop instances in Multi-Node cluster

Multi-Node_Cluster Configuration

Some important things in hadoop configuration

• In Multi-Node configuration once the configuration is done we have to start only the Name node and all other data node(slave) will start automatically.
• Before configuring hadoop make sure that all the machines are accessible each other
• If not create and distribute SSH keys to access each other.
• Configure dfs.data.dir and dfs.name.dir location in all the nodes(name and data nodes). data directory is different for different nodes. All the slaves uses their own data directory.

In configuration file core-site.xml,  property name fs.default.name is the file system of name(master) node. This is same as for slaves (data node)also.

Map Reduce Frame work over hadoop

This frame work you can download from Apache’s site and install in all your hadoop instances. This contains some sample applications to perform the map reduce task. By using map reduce libraries you can write your own map reduce programs.

For more details please see Map Reduce Tutorial

below noted some questions and its answers

How to write TEXT vertically?

By using rotation transformation

How to use rotation transformation?

a) Set the translation point, means the rotation is happening based on this point.

b) Rotate  - PI/2 (minus PI/2, it is 3.14 in Math api)

c) Write the TEXT String.

After vertical text drawing, Why my existing graphical content is changed or new graphical content is not showing properly? (It is just a fundamental graphical drawing technique only)

After translation and rotation we have to do the reverse process for incorporating the new graphical changes.  The whole process looks like,

a) translate to x,y
b) rotate to -Math.PI/2
c) draw the TEXT string
d) do reverse rotate, rotate to Math.PI/2
e) do a reverse translation, translate to -x,-y

Example code

g2d.translate(x, y);
g2d.rotate(-Math.PI/2);
g2d.drawString(text, 0,0);
g2d.rotate(Math.PI/2);
g2d.translate(-x, -y);

One solution for this is,

                      a) Write a servlet  and use java2D for drawing.

                      b) This servlet returns graphics as any image file format.

                      c) Create a widget that is capable of displaying image from this servlet (You can use GWTCanvas for displaying image)

                       d) Invoke the servlet from the widget.

Servlet Sample code:

 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
 Graphics2D g2d = bufferedImage.createGraphics();
 g2d.setColor(Color.black);
 g2d.fillRect(0, 0, width, height);

 response.setContentType(“image/png”);
 OutputStream os = response.getOutputStream();
 ImageIO.write(bufferedImage, “png”, os);
 os.close();

GWT Sample Code:

ImageLoader.loadImages({GWT.getModuleBaseURL() + “/ServletName?rand=”+Random.nextInt(55555)}, new ImageLoader.CallBack() {
   public void onImagesLoaded(ImageElement[] imageElements) {
    ImageElement img = imageElements[0];
    canvas.setWidth(img.getWidth()+”px”);
    canvas.setHeight(img.getHeight()+”px”);
    canvas.drawImage(img, 0, 0);
   }});

One third party widget available for displaying timeline information is SIMILE’s Timeline widget. It is available at  http://code.google.com/p/gwtsimiletimeline/. It is easy to incooporate with our applications and also possible to write our own renders for data display. Those features are impressive.  The implemenation details are neatly explained in above link.