One program for pc and mac with different imports

Question

I am trying to port my Java program from the PC to the MAC. I would like to have one program that works on both, the PC and the MAC. So I am using the
if (System.getProperty("mrj.version") == null) //PC
else //MAC
condition to see if I am on the PC or MAC for making sure that the About menu is at the Help menu on top of the application window (PC) or at the Program menu on top of the screen (MAC) and the Control key (PC) or Command key (MAC) is used.
However, the Mac also uses additional imports, such as
import com.apple.laf.*;
import com.apple.mrj.*;
import com.apple.eawt.*;
I cannot make an if statement before the imports. How can I make sure that the imports are only used on the MAC?
Thanks for your time!

Answer 1

>
..my program has a GUI...>Cool. OK - if you have not tried applications launched by JWS (Java Web Start) it is usually handy to get a feel for how they work for the end user. The biggest difference is between sandboxed applications, and ones that request extended permissions in the form of either j2ee-application-client-permissions or all-permissions. The first removes the warning banner from the bottom of windows, and adds a few other allowable actions, while the latter is, as it implies - all permissions.
Examples of all-permissions/sandboxed can be seen in this [demo of the JNLP fileservice|http://pscode.org/jws/api.html#fs].
>
.. It is a computer graphics program, and it has a Tools palette where you can specify what and how you want to draw or select or move, and it has a Measurements palette, where you can use numbers for your drawing.>Does it offer to export the resulting graphics (e.g. save them to disk)? Does the program load graphic objects from disk? The reason I pointed to a demo of the differences between sand boxed and trusted apps., is because if the app. wants to 'access the local disks' it will either need to request all-permissions or as demonstrated in the example, use the [JNLP API|http://java.sun.com/javase/6/docs/jre/api/javaws/jnlp/index.html] (a group of classes only available to apps. launched by webstart) to do common things like access disks or printer, or take control of downloads...
If you click the [Launch File Service (sandboxed) demo|http://pscode.org/jws/filetest-sandbox.jnlp] link, you can see what the experience would be like for the end user if the app. were converted to use the JNLP API for file I/O and was delivered entirely sandboxed.
Of course, if your app. could work entirely sand boxed, like an applet - no code signing or extra permissions would be necessary, but that is uncommon for a desktop application.
>
So could you please give me some explanation or reference how to do launching it using webstart, and putting the mac specific resources into a resource section flagged for the Mac? >Launching an app. via webstart is not entirely 'simple', especially if you are new to it. OTOH it is well worth the effort - for the sake of the end user.
The very basics of webstart is that you create a JNLP file to launch the app., I guess it is similar to the Mac .plist (or whatever they are) that you are discussing in another thread. Java JNLP files are a form of XML. Here is an example of what one might look like for an app. that provides different resources to different OS.
<?xml version="1.0" encoding="UTF-8"?>
<jnlp spec="1.0"
      codebase="http://ananya.com/lib"
      href="ananyacurves.jnlp">
  <information>
    <title>Ananya Curves</title>
    <vendor>Ananya Systems</vendor>
    <description>Ananya Curves - Computer Graphics</description>
    <offline-allowed/>
    <shortcut online="false">
      <desktop/>
      <menu submenu="AnanyaSystems"/>
    </shortcut>
  </information>
  <security>
       <all-permissions />
  </security>
    <resources>
      <j2se version="1.6+" />
      <jar href="AnanyaCurves.jar" main='true' />
    </resources>
    <!-- This is it! Supply the mac specific classes ONLY to Macintosh OS. -->
    <resources os='Mac'>
      <jar href="mac-specific.jar" />
    </resources>
  <application-desc />
</jnlp>
>
..Well, I am a complete beginner at this.>It can be a steep learning curve to first use JWS successfully, but it is well worth it.
There is a good [overview of webstart|http://java.sun.com/developer/technicalArticles/Programming/jnlp/], but I also find it handy to keep the documentation on the [JNLP file syntax|http://java.sun.com/j2se/1.5.0/docs/guide/javaws/developersguide/syntax.html] nearby.
Unfortunately many IDEs (and people) are not that competent at writing JNLP files, so I provide a JNLP XSD and [YAX-V|http://pscode.org/xml/xmltools.html#yaxv] to validate them.