从Java程序传递SWI-Prolog查询

Question

I have a Query generated by my Java Program in Query Variable. I want to send this to SWI-Prolog to get the solution of this. The following shows the subcode I wrote in Java to communicate with SWI-Prolog.

  Process P= new ProcessBuilder("C:\\Program Files\\swipl\\bin\\swipl-win.exe").start();
        BufferedReader processOutput = new BufferedReader(new InputStreamReader(P.getInputStream()));
        BufferedWriter processInput = new BufferedWriter(new OutputStreamWriter(P.getOutputStream()));

        String commandToSend = Query;
         processInput.write(commandToSend);

But the SWI-Prolog Window opens up but the comand I am writing to ProcessInput is not being sent to SWI-Prolog. Can someoe suggest me the best way to do this? I need the output of the Query Execution from SWI-Prolog in a File as well.

Answer 1

Save your query to external text file and execute swipl from command line (with appropriate options set) and redirect output to another text file. Then, read that output file.

Example:

1. Save your query to QUERY.TXT as :- query.
2. Run swipl with redirection to OUTPUT.TXT: swipl -s QUERY.TXT -g halt --quiet > OUTPUT.TXT
3. Read contents of OUTPUT.TXT

Also, I suspect you should use combination of Runtime.getRuntime().exec(...) and waitFor(...) to wait for swipl for generating output.