有没有办法从java执行Objective-C应用程序？

Question

I have an Objective-C console application that already exists. I'm not the one who developed it, so i don't have easy access to the code. So changing the code might not be an option, but what i do know is that for compiling, it requires Cocoa and SystemConfiguration. (i was told in an email) Once run, it has a prompt waiting for a command and there's a text output result after that command. Is there a way that i can take this application and run it within java and capture the output?

I've never done OSX development before but i am aware that C code can work well with Java and Obj-c is a superset of C but with the framework requirements, it seems clear that objects are used somewhere in the code.

I have seen something like rococoa but hasn't been updated in some time (2009) does it still work with mountain lion?

Answer 1

When you say you have a Objective-C application, you really mean you have a binary/executable compiled for Mac OS?

If so, you can Class ProcessBuilder to create operating system processes.

Process p = new ProcessBuilder("myCommand", "myArg").start();

Note: this solution will only work on Mac OS X. Also you might have some security issues because Java loves to run in a sandbox.

Answer 2

If you want to create a subprocess and also to interchange informations between it and your main program, I think the following code will help you.

It creates a subprocess by calling a binary/executable file, and then writes something (eg. a command) to its input stream and reads some text:

import java.io.*;


public class Call_program
{
    public static void main(String args[])
    {
        Process the_process = null;
        BufferedReader in_stream = null;
        BufferedWriter out_stream = null;

        try {
            the_process = Runtime.getRuntime().exec("...");   //replace "..." by the path of the program that you want to call
        }
        catch (IOException ex) {
            System.err.println("error on exec() method");
            ex.printStackTrace();  
        }

        // write to the called program's standard input stream
        try
        {
            out_stream = new BufferedWriter(new OutputStreamWriter(the_process.getOutputStream()));
            out_stream.write("...");     //replace "..." by the command that the program is waiting for
        }
        catch(IOException ex)
        {
            System.err.println("error on out_stream.write()");
            ex.printStackTrace();  
        }

        //read from the called program's standard output stream
        try {
            in_stream = new BufferedReader(new InputStreamReader(the_process.getInputStream()));
            System.out.println(in_stream.readLine());   //you can repeat this line until you find an EOF or an exit code.
        }
        catch (IOException ex) {
            System.err.println("error when trying to read a line from in_stream");
            ex.printStackTrace();  
        }
    }
}

ref.

http://publib.boulder.ibm.com/infocenter/iseries/v5r4/index.jsp?topic=%2frzaha%2fiostrmex.htm

Answer 3

If this list is comprehensive then there is not a pure Objective-C solution.

http://en.wikipedia.org/wiki/List_of_JVM_languages

Your next options are solutions to call C from Java - which is easy to Google in its own right so I won't include information here - or more decoupled solutions (which are very likely what you want) eg use a message bus, such as ZeroMQ or RabbitMQ.

I strongly recommend avoiding bridging two languages unless you have a particularly unusual architecture or hardware requirement. Bridging two languages is O(n^2) APIs to learn in the number of languages, implementing message queues is O(n).