Question

I’m writing an application with a Java GUI which calls some FORTRAN code. I want to return a file (solution.ps) which is updated and compiled based on changes in the FORTRAN code, which are created earlier in my ActionPerformed method. However the code I have at present just returns the old version of the file rather than waiting for the updated results of the cmd compilation. Is there a way to make the cmd wait for the process to run before completing the next step? (It works fine running directly from cmd)

I’ve searched but can’t find anything except process.waitFor() which won’t seem to pause the execution at the right point. Tried Thread.waitFor() too.

I’m thinking this could be useful for anyone who wants to send user inputs to another program and return a compiled result which uses these inputs.

Anyway here is the code, thanks in advance for any help and I hope I made the problem clear.

String[] command ={"cmd",};
        try {
            Process p = Runtime.getRuntime().exec(command); 
            new Thread(new SyncPipe(p.getErrorStream(), System.err)).start();
            new Thread(new SyncPipe(p.getInputStream(), System.out)).start();
            PrintWriter stdin = new PrintWriter(p.getOutputStream());
            stdin.println("cd c:\\g77");     
            stdin.println("g77setup.bat");
            stdin.println("cd c:\\users\\laurence\\workspace\\areaplanner");
            stdin.println("g77 -O4 genpack.f -o genpack");
            stdin.println("genpack");
            stdin.println("5"); 
            /* 
             * The following line sets the time to run the FORTRAN code for  
             * - need to wait for this to complete before calling mpost
             */
            stdin.println("30"); 

            stdin.println("mpost solution.mp");
            stdin.println("latex solution.tex");
            stdin.println("dvips solution.dvi -o solution.ps");
            stdin.close();
            } catch(IOException e4){}

Answer 1

You are only runnng the windows shell command. To fix, suggest writing the batch file first and wait for it to finish:

String command = "cmd /c mybatchfile.bat";
Process p = Runtime.getRuntime().exec(command);
p.waitFor();

To get another section to kick off before the the first set of commands have completed, you will have to write another batch file and repeat the above. Make sure you have both process then in separate threads.