Saturday, October 04, 2003

Directories are Java source file package names

After reading this blog by Gregg Wonderly and some of the comments posted at the blog I decided to write this blog entry.
For a long time I used to think directories are not Java source file package names because Chapter 7 of Java language specification said so. Also many a times(For any product that you work on for long time) maintaining directories as Java source file package names is a pain. Imagine you are developing a product called javamagic. You are working for a oraganization which has several suborganizations and with several products for each sub organization. If your java source files must be in a directory tree mirroring the package name, your source directory would typically look something like this:

Having this structure is pain and sounds dumb because you know com/javaswamy/jone/javamagic is always constant and there is absolutely no need to maintian this filesystem hierarchy as you know what you are working on. If possible a simple hierarchy like this would be what everyone likes to have:

This is easy to navigate and presents developer view of the code.

Now lets get back to reality. Though Java Language Specification doesn't impose the restiction of Directories are Java source file package names, JavaDoc does. JavaDoc tool faq states "If your classes do not all belong to the unnamed package, you must put them in directories named after the packages.". So if you need to generate javadocs for your project and use JavaDoc tool to generate the documentation, Directories are Java source file package names.

Like many other java programmers, I would love to see JavaDoc team solve these problems that exist since JDK1.1 days:
1. Directories are Java source file package names.
2. Deprecation warning is suppressed if the compilation unit containing the deprecation is being compiled at the same time as the compilation unit using the deprecated class or member.

Wednesday, October 01, 2003

Office: 1.1 released announced first major update to OpenOffice. 1.1 is now final and English version is available for download on Windows, Solaris and Linux. I have been using 1.0.x versions and 1.1 RC's for a while. With every update OpenOffice is getting better and better and better compatability with M$ Office. OpenOffice is now the only office suite on my home machine.
The two new major features for me in 1.1 update are export to PDF format from Writer and export to Macromedia Flash format (.swf) from Impress. Support for export to PDF got better with every update.
Checkout my blog archive for the month 2003_09 exported to PDF from Writer:Kumar Mettu's Blog.pdf. The only data lost from saved html file is Hyperlinks.
Here is a simple presentation exported to Macromedia Flash format (.swf):

Check out XML Essentials book online.

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.'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;
002 import;
004 import;
005 import;
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;
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 {
023     private Display display;
024     //Exit command.
025     private Command  exitCommand = new Command"Exit", Command.SCREEN, );
026     //SF Weather URL.
027     private static final String SF_URL =
028         "";
030     /**
031      * Weather MIDlet constructor.
032      */
033     public Weather() {
034        display = Display.getDisplay(this);
035     }
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.addCommandexitCommand );
050             forecast.setCommandListenerthis );
051             display.setCurrent(forecast);       
052        }
053     }
055     /**
056      * Pause, discontinue ....
057      */
058     public void pauseApp() {
060     }
062     /**
063      * Destroy. Cleanup everything.
064      */
065     public void destroyApp(boolean unconditional) {
066     }
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();
079         try {
080           sc = (StreamConnection);
081           in = sc.openInputStream();
082           int ch;
083           while ((ch = != -1) {
084              b.append((charch);
085           }
087         finally {
088            if (in != null) {
089               in.close();
090            }
091            if (sc != null) {
092               sc.close();
093            }
094         }
096         Form forecast = new Form("Weather at SF");
097         forecast.append(b.toString());
098         forecast.addCommandexitCommand );
099         forecast.setCommandListenerthis );
100         display.setCurrent(forecast);
101     }
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 commandActionCommand c, Displayable d ){
109         if (c == exitCommand){
110             exit();
111         }
112     }
114   /**
115    * Distroy app when exit button is used.
116    */
117     private void exit(){
118         destroyApp(true);
119         notifyDestroyed();
120     }    
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.

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.