Opening a client file problem

Question

Building a swing client mail application has one huge hickup and can't think of a good solution. How do you automatically open an email attachment?? If its a .doc document, it should open a word document automatically instead of reinventing the wheel and code some Java RTF viewer.
A lot of attachments are compressed, you mean you have to code it all in Java? That would be absurd? With 100 now common mime types, anyone have any good suggestions of doing this.
For example - Would the windows "start" command be a good idea to simply open the folder if not a text/html or image (gif/jpg) file?
What about linux and unix and mac?? Whats the OS command to open the mail cache attachments folder? Not happy that Java doesn't support a native method to open a file. Why is that?
Hope people reply to this and bring some ideas that are effective and would not be too troublesome to implement or re-invent the wheel??
Thanks
Abraham Khalil

Answer 1

I realize this is about a year late, but in case anyone stumbles across this in a query here's my two cents:
I haven't researched this thoroughly enough to explain how it works, but I researched it enough to produce working code. This worked on... let me see... Windows 2000, 98, and Mac (running 1.3.1, but it should work with 1.4.2 too).
Note this referenecs a few of my own classes...
     /** Triggers the OS to open a file with its default application.  Returns true if successful.
     public static boolean openFile(File file) {
          Process process = null;
          if(usingMac) {
               try {
                    // from: http://www.jguru.com/faq/view.jsp?EID=430093
                    String[] cmd = {"open",file.getAbsolutePath()};
                    process = Runtime.getRuntime().exec(cmd);
               } catch(Throwable t) {}
          } else if(usingWindows) {
               try {
                    I found an amazing trick at:
                     http://www.michael-thomas.com/java/javacert/MyLaunchDefaultBrowser.html
                     Basically this means Windows decides how to open a program.
                    String cmd = "rundll32 url.dll,FileProtocolHandler" + " "+file.getAbsolutePath();               
                    process = Runtime.getRuntime().exec(cmd);
               } catch(Throwable t) {}
          if(process==null) return false;
          while(true) {
               try {
                    return (process.waitFor()==0);
               } catch(InterruptedException e) {}
               //don't hog the CPU while our other process is working:
               try {
                    Thread.sleep(20);
               } catch(InterruptedException e) {
                    Thread.yield();
     }We encountered 1 problem with the code above:
Under really restricted settings on Mac, the code above would refuse to open a "help.html" file. So in addition to the code above, we now check the file type. if it's HTM or HTML, we trigger the browser-specific code. Of course this only helps with HTML files (or other browser-friendly files), but in this case it was enough to get by.
Lots of useful info about java-working-with-browsers is available here:
http://ostermiller.org/utils/Browser.html
As a closing note: are you sure you want to automatically open attachments? That's the kind of feature viruses prey on. Not to mention trojan horses. It's a huge security risk to open a file like that; I would only consider it:
1. If I were operating in a closed network.
2. If I had a virus-checking program nearby, and before launching a file I could ask it to check it for me.
Even then I'd make the user very aware of the risks involved, and would not enable it by default.
hope this helps. Sorry nobody responded sooner.