Kumar Mettu's Blog

Life of a java disciple

Blog

Mail Me

RSS Feed

Sponsor a Child

Archives

J2EE Blogs:

Cedric
Cameron
Rickard

J2ME Blogs:

Kalimantan
Russell
Fred

.NET Blogs:

Raymond
Chris
Don Box

Important Links:

JSR127

International Users:

French German Japanese

Tuesday, September 30, 2003

J2ME: Get Weather Forecasts Free

Weather on Demand is one of the most common applications of SMS. Few of weather service examples are:

1. Weather alerts from Verizon .
2. Weather Network and TELUS Mobility's On Demand Weather service and
3. Weather.com's Radar on Mobile Phones.
With a simple MIDlet you can get Weather forcasts free on your phone. US government provides free weather forecasts here. Note that the weather forecasts are not as high quality as commercial services. The simple MIDlet here displays weather at SF(modify the URL to point to your city):

001 import java.io.IOException;
002 import java.io.InputStream;
003 
004 import javax.microedition.io.Connector;
005 import javax.microedition.io.StreamConnection;
006 import javax.microedition.lcdui.Command;
007 import javax.microedition.lcdui.CommandListener;
008 import javax.microedition.lcdui.Display;
009 import javax.microedition.lcdui.Displayable;
010 import javax.microedition.lcdui.Form;
011 import javax.microedition.midlet.MIDlet;
012 
013 
014 /**
015  * MIDlet to display weather forecast for SF.
016  *
017  * @author Kumar Mettu
018  * @version 1.0
019  *
020  */
021 public class Weather extends MIDlet implements CommandListener {
022 
023     private Display display;
024     //Exit command.
025     private Command  exitCommand = new Command( "Exit", Command.SCREEN, 1 );
026     //SF Weather URL.
027     private static final String SF_URL =
028         "http://weather.noaa.gov/pub/data/forecasts/city/ca/san_francisco.txt";
029 
030     /**
031      * Weather MIDlet constructor.
032      */
033     public Weather() {
034        display = Display.getDisplay(this);
035     }
036 
037     /**
038      * This will be invoked when we start the MIDlet.
039      * Display the downloaded data. If an error occurs while downloading
040      * the data display the error to user.
041      *
042      */
043     public void startApp() {
044         try {
045             getViaStreamConnection();
046         } catch (IOException e) {
047             Form forecast = new Form("Error Downloading");
048             forecast.append(e.getMessage());
049             forecast.addCommand( exitCommand );
050             forecast.setCommandListener( this );
051             display.setCurrent(forecast);       
052        }
053     }
054 
055     /**
056      * Pause, discontinue ....
057      */
058     public void pauseApp() {
059 
060     }
061 
062     /**
063      * Destroy. Cleanup everything.
064      */
065     public void destroyApp(boolean unconditional) {
066     }
067 
068     /**
069      * Download the weather and display it.
070      *
071      * @throws IOException when IO Error occurs while downloading
072      *  data from URL.
073      */
074     private void getViaStreamConnection() throws IOException {
075         StreamConnection sc = null;
076         InputStream in = null;
077         StringBuffer b = new StringBuffer();
078 
079         try {
080           sc = (StreamConnection)Connector.open(SF_URL);
081           in = sc.openInputStream();
082           int ch;
083           while ((ch = in.read()) != -1) {
084              b.append((char) ch);
085           }
086 
087         } finally {
088            if (in != null) {
089               in.close();
090            }
091            if (sc != null) {
092               sc.close();
093            }
094         }
095 
096         Form forecast = new Form("Weather at SF");
097         forecast.append(b.toString());
098         forecast.addCommand( exitCommand );
099         forecast.setCommandListener( this );
100         display.setCurrent(forecast);
101     }
102 
103     /**
104      * Indicates that a command event has occurred on Displayable d.
105      * @param c - a Command object identifying the command.
106      * @param d - the Displayable on which this event has occurred.
107      */
108     public void commandAction( Command c, Displayable d ){
109         if (c == exitCommand){
110             exit();
111         }
112     }
113 
114   /**
115    * Distroy app when exit button is used.
116    */
117     private void exit(){
118         destroyApp(true);
119         notifyDestroyed();
120     }    
121 
122 }

You can download Weather.jar and Weather.jad directly. Tested on my i88s. Here is the screen snapshot of Motorola i88s simulator:

This can be further extended to support features like:
1. Select the city where you want weather forcast(using kxml)
2. If your phone supports GPS( like my Motorola i88s), you can display weather forecasts for your current location.

posted by Kumar at 12:09 AM

Monday, September 29, 2003

M$: MSBuild - M$ version of ANT

Microsoft is coming up with a build tool(MSBuild). MSBuild is the next generation build engine and platform for Visual Studio .NET. Microsoft has a session about the new build system during Microsoft Professional Developers Conference 2003.
From introduction it looks like it will ship with the .NET redistributable and not Visual Studio. Also it appears that MSBuild will be an XML based Ant like tool with XML files to drive the build. Of course a similar build tool exist as Nant.
This is yet another block that has been missing in .NET (compared to J2EE) that Microsoft decided to fill.

posted by Kumar at 6:20 PM

Saturday, September 20, 2003

J2SE: Taking screen snapshots in JAVA

As programmers many a times we need take snap shots of our screens. If we can take snap shot in java why use OS specific way to take a snap shot?
Here is a simple code example of taking snapshot in java (Either PNG format or JPEG format):

01 import java.awt.AWTException;
02 import java.awt.Dimension;
03 import java.awt.Rectangle;
04 import java.awt.Robot;
05 import java.awt.Toolkit;
06 import java.awt.image.RenderedImage;
07 import java.io.File;
08 import java.io.IOException;
09 import javax.imageio.ImageIO;
10 
11 /**
12  * A Simple program that saves current screen snapshot.
13  * Supported formats png and jpg.
14  * Usage java ScreenSnapShot <<outputfilename>>
15  *
16  * @author Kumar Mettu
17  * @version 0.61
18  */
19 public class ScreenSnapShot {
20 
21     public static void main(String[] args) throws IOException,AWTException {
22 
23         String saveFileName = "default.png";
24         String saveFileFormat = "png";
25 
26         if (args.length > 0)
27             saveFileName = args[0];
28 
29         if (saveFileName.toLowerCase().endsWith(".png")) {
30             saveFileFormat = "png";
31         } else if (saveFileName.toLowerCase().endsWith(".jpg") ||
32                    saveFileName.toLowerCase().endsWith(".jpeg")) {
33             saveFileFormat = "jpg";
34         } else {
35             System.err.println("Only png and jpg formats are supported.");
36             System.exit(1);
37         }
38 
39         // get current sceen size for snapshot.
40         Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
41         Rectangle screenRect = new Rectangle(screenSize);
42 
43         // create current screen snapshot
44         RenderedImage image = (new Robot()).createScreenCapture(screenRect);
45 
46         if (ImageIO.write(image, saveFileFormat, new File(saveFileName))) {
47             System.out.println("Screen snap shot is saved as :" + saveFileName);
48         } else {
49             System.out.println("Unable to save snap shot");
50         }
51     }
52 }

This code requires J2SE1.4. There is no real use of this code unless you extend it to make use of it(like taking snapshots at fixed intervals etc...).

posted by Kumar at 9:44 PM

Friday, September 19, 2003

General: China to help Europe develop GPS rival

New Scientist reports China has joined a European effort to develop a new global satellite navigation system that would offer a more accurate civilian alternative to the Global Positioning System. The Galileo system will be precise to within a meter, while the civilian GPS service is accurate to around 10 meters. This development adds to the consternation of the U.S. military, which controls the GPS and currently enjoys the option of downgrading the civilian service during military conflicts.

posted by Kumar at 9:17 PM

Sunday, September 14, 2003

Microsoft links with Motorola to launch mobile phone

Telegraph | Money | Microsoft links with Motorola to launch mobile phone: "Microsoft's bid to dominate the market for mobile phone operating systems will receive a boost today when the US software giant launches its first phone with a major handset maker."

Untold story:In a related product launch Steve Ballmer, Chief Executive Officer Microsoft Corp announced general availability of the Blue Screen of Death sized down for use in Motorola handset

posted by Kumar at 9:45 PM

Friday, September 12, 2003

J2SE: A nice tool to learn API differences

JDiff is a Javadoc doclet which generates an HTML report of all the packages, classes, constructors, methods, and fields which have been removed, added or changed in any way, including their documentation, when two APIs are compared. This is very useful for describing exactly what has changed between two releases of a product. Only the API (Application Programming Interface) of each version is compared. It does not compare what the source code does when executed.

Sample Reports:
Comparing J2SE1.4.0 and J2SE1.4.1
Comparing J2SE1.3.1 and J2SE1.4

posted by Kumar at 11:22 AM

Tuesday, September 09, 2003

J2ME: Turning your phone into web Server.

I wrote a simple midlet which turns my Phone into simple web server. To keep the code simple, I removed the additional GPS capabilities. Currently the web server listens to port 8000 and repsonds "Hello, I am Kumar Mettu's Phone. Thanks for Visiting" for all requests that are sent to this tiny web server. Note that this code is tested only on Motorola i88s with Nextel Total Connect Service.

Here is the code for the tiny web server:

001 import java.io.IOException;
002 import java.io.InputStream;
003 import java.io.PrintStream;
004 
005 import javax.microedition.io.Connector;
006 import javax.microedition.io.StreamConnection;
007 import javax.microedition.io.StreamConnectionNotifier;
008 import javax.microedition.lcdui.Display;
009 import javax.microedition.midlet.MIDlet;
010 
011 /**
012  * MIDlet working as simple personal WebServer.
013  * Currently this serves simple HTTP GET operation.
014  *
015  * @author Kumar Mettu
016  * @version 0.61
017  */
018 
019 public class WebServer extends MIDlet {
020 
021     private Display display;
022 
023     StreamConnectionNotifier scn = null;
024 
025     /**
026      * Default constructor.
027      */
028     public WebServer() {
029        display = Display.getDisplay(this);
030     }
031 
032     /**
033      * This will be invoked when we start the MIDlet
034      */
035     public void startApp() {
036         try {
037             scn =(StreamConnectionNotifier)Connector.open("serversocket://:8000");
038             while (true) {
039                 StreamConnection sc = (StreamConnection)scn.acceptAndOpen();
040 
041                 // service the connection in a separate thread
042                 Connection c = new Connection(sc);
043                 c.start();
044             }
045 
046 
047         } catch (IOException e) {
048             //Handle Exceptions any other way you like.
049             //No-op
050         }
051     }
052 
053     /**
054      * Pause, discontinue ....
055      */
056     public void pauseApp() {
057         try {
058             if (scn != null)
059                 scn.close();
060         } catch(Exception e) {
061         }
062 
063     }
064 
065     /**
066      * Destroy. Cleanup everything.
067      */
068     public void destroyApp(boolean unconditional) {
069         try {
070             if (scn != null)
071                 scn.close();
072         } catch(Exception e) {
073         }
074     }
075 
076     /**
077      * Thread to handle client request.
078      */
079     class Connection extends Thread
080     {
081 
082         public Connection(StreamConnection c) {
083             client = c;
084         }
085 
086         /**
087          * Handles client request.
088          */
089         public void run() {
090             InputStream s = null;
091             PrintStream out = null;
092             StringBuffer b = new StringBuffer();
093             try {
094 
095                 s = client.openInputStream();
096 
097                  //Ignore reading request to reduce the amount of data
098                  //transfered to Phone.
099                 /*int ch;
100                 while((ch = s.read()) != -1) {
101                     b.append((char) ch);
102                 }
103                 System.out.println(b.toString());*/
104 
105                 out = new PrintStream(client.openOutputStream());
106                 String response =
107                              "&lt;HTML&gt;"+
108                              "&lt;HEAD&gt;"+
109                                 "&lt;TITLE>Kumar's Location&lt;/TITLE&gt;"+
110                              "&lt;/HEAD&gt;"+
111                              "&lt;BODY&gt;Hello, I am Kumar Mettu's Phone. "+
112                                      "Thanks for Visiting.&lt;/BODY&gt;"+
113                              "&lt;/HTML&gt;";
114                 out.println("HTTP/1.0 200 OK\n");
115                 out.println(response);
116 
117             }
118             catch (Throwable ioe) {
119                 //Handle Exceptions any other way you like.
120                 //No-op
121             }
122             finally {
123                 try {
124                     if (s != null)
125                         s.close();
126                     if (out != null)
127                         out.close();
128                     if (client != null)
129                         client.close();
130                 }
131                 catch (IOException ioee) {
132           //Handle Exceptions any other way you like.
133           //No-op
134                 }
135             }
136         }
137 
138         private StreamConnection client;
139     }
140 
141 }
142

I know there is no business value for this web server. But hey turning phone into a web server and viewing it serve web pages to browser is fun :-)

posted by Kumar at 11:47 PM

J2ME: My new J2ME-GPS phone

Since my old phone is more than 2 years old, I bought a new Motorola i88s phone which has J2ME and GPS support.
I added some cool J2ME applications which will probably be blogging about in coming days.

posted by Kumar at 11:31 PM

Monday, September 08, 2003

Molecular Expressions: Science, Optics and You - Powers Of 10: Interactive Java Tutorial

Molecular Expressions: Science, Optics and You - Powers Of 10: Interactive Java Tutorial: "View the Milky Way at 10 million light years from the Earth. Then move through space towards the Earth in successive orders of magnitude until you reach a tall oak tree just outside the buildings of the National High Magnetic Field Laboratory in Tallahassee, Florida. After that, begin to move from the actual size of a leaf into a microscopic world that reveals leaf cell walls, the cell nucleus, chromatin, DNA and finally, into the subatomic universe of electrons and protons."

posted by Kumar at 8:21 AM

Thursday, September 04, 2003

StarOffice makes strong inroads in India

StarOffice makes strong inroads in India: "'In a scenario where enterprises are looking to bring down costs and increase productivity, StarOffice has emerged to be a viable option. In the last few months, StarOffice has gained substantial penetration into the Indian markets across segments like corporations, home users and government,' says K P Unnikrishnan, country head, marketing, Sun Microsystems India."

posted by Kumar at 6:12 AM

Wednesday, September 03, 2003

Send your prayer to GOD using SMS

Indians can send an SMS PUJA (prayer) to BPL and have the prayers recited for them at a popular Bombay temple, during the annual Ganesh Chaturthi festival. For just 51 rupees or $1.10, subscribers can avoid the hassle and aggravation of temple queues and text Ganesh instead.

posted by Kumar at 6:12 PM

Tuesday, September 02, 2003

Yahoo! News - Sun Mulls Joining Java Eclipse Effort

Yahoo! News - Sun Mulls Joining Java Eclipse Effort: "'Sun believes that Eclipse will hit a wall in terms of performance and compatibility because of distinctions between its NetBeans ... approach and Eclipse's ... approach, but at the moment, Eclipse is the clear leader,' said Stephen O'Grady, an analyst with RedMonk LLC, a market research company based in Bath, Maine."

posted by Kumar at 7:01 PM

Monday, September 01, 2003

Dear Mr Fleury stop spamming us

Unfortunately JBossGroup thinks none of the rules that applies to every enterpise applies to them. Its a minimum courtesy to have a link to "remove me" in news letters and marketing junk. Here is the latest mail sent by Marc F to what ever list he maintains:

Hello,

Just a quick one to cover August.

August was a great month for JBG, our best so far with record sales and
booming business. We will unveil the service partnership program soon.
On an interesting bit of news, JBoss made it #2 on the Computer Reseller
News as 'fastest growing certification in importance for large SI's'.

If you are in Europe and back from holiday, you may want to register for
the Stockholm training on September 8 (that is next week). Also let me
draw you attention to the OCT bootcamp in Amsterdam, you don't want to
miss that one. That is Oct 12.

Finally, there a number of events coming up where you can catch us.
http://www.jboss.org/index.html?module=html&op=userdisplay&id=news/event
s
You can catch Scott at the Web Services Edge West on Oct 1 and me in
Paris for the XML day on Oct 7, before the bootcamp on Oct 12, did we
say it was in Amsterdam?

All information is on our website at www.jboss.org and
www.jbossgroup.com

Regards

marcf

xxxxxxxxxxxxxxxxx
Marc Fleury, Ph.D
Founder
JBoss Group, LLC
xxxxxxxxxxxxxxxxx

_______________________________________________
jboss-news mailing list
jboss-news@mail.jboss.org
http://mail.jboss.org:8080/mailman/listinfo/jboss-news

The link http://mail.jboss.org:8080/mailman/listinfo/jboss-news gives server error:
HTTP Status 500 - No Context configured to process this request

Mark, next time u send your crap to us please provide a remove me link.

After publishing this on my blog, Fleury woke up and sent a mail to jboss-news with the subject "How to unsubscribe + quickie". Here are the full contents of his Email:

Folks,

Just a quickie to remind you that if you want to unsubscribe from this
list there should be directions at the bottom. We finally fixed the
port issues so you can unsubscribe by clicking below.

We just reconciled the lists and there are 40,000 entires on the list.
That is quite a bit of you that have subscribed to jboss-news. I am
looking forward to this out-reach mass channel as communication is
king.

Another quickie, we finished the services partners contracts and we
hope
to release soon. I also want to remind the europeans that we will be
in
amsterdam for bootcamp on Oct 11-12, you don't want to miss it,
register
soon.

Let me know if you encounter problems in the unsubscribe for those of
you going offline, we recently fixed a glitch that pointed to 8080
instead of the main port 80. It should work, let me know if it
doesn't.

Kind regards

marcf

xxxxxxxxxxxxxxxxx
Marc Fleury, Ph.D
Founder
JBoss Group, LLC
xxxxxxxxxxxxxxxxx

_______________________________________________
jboss-news mailing list
jboss-news@mail.jboss.org
http://mail.jboss.org/mailman/listinfo/jboss-news

I am just glad I didn't get a reply **** my **** from Marc. May be he is maturing.

posted by Kumar at 10:00 PM

Blog Home