REngine does not invoke R Console

2019-07-19 01:32发布

问题:

Collected the code from one of the site, it does not invoke R Console from REngine. It breaks after creating REngine and does not go to try and catch.

problem:

Rengine re=new Rengine(args, true, new TextConsole2());
System.out.println("Rengine created, waiting for R");

Sample code (rtest2.java) - rJava/examples

import java.io.*;

import java.awt.*;
import javax.swing.*;

import org.rosuda.JRI.Rengine;
import org.rosuda.JRI.REXP;
import org.rosuda.JRI.RMainLoopCallbacks;
import org.rosuda.JRI.RConsoleOutputStream;

class TextConsole2 implements RMainLoopCallbacks
{
    JFrame f;

    public JTextArea textarea = new JTextArea();

    public TextConsole2() {
        f = new JFrame();
        f.getContentPane().add(new JScrollPane(textarea));
        f.setSize(new Dimension(800,600));
        f.show();
    }

    public void rWriteConsole(Rengine re, String text, int oType) {
        textarea.append(text);
    }

    public void rBusy(Rengine re, int which) {
        System.out.println("rBusy("+which+")");
    }

    public String rReadConsole(Rengine re, String prompt, int addToHistory) {
        System.out.print(prompt);
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            String s=br.readLine();
            return (s==null||s.length()==0)?s:s+"\n";
        } catch (Exception e) {
            System.out.println("jriReadConsole exception: "+e.getMessage());
        }
        return null;
    }

    public void rShowMessage(Rengine re, String message) {
        System.out.println("rShowMessage \""+message+"\"");
    }

    public String rChooseFile(Rengine re, int newFile) {
    FileDialog fd = new FileDialog(f, (newFile==0)?"Select a file":"Select a new file", (newFile==0)?FileDialog.LOAD:FileDialog.SAVE);
    fd.show();
    String res=null;
    if (fd.getDirectory()!=null) res=fd.getDirectory();
    if (fd.getFile()!=null) res=(res==null)?fd.getFile():(res+fd.getFile());
    return res;
    }

    public void   rFlushConsole (Rengine re) {
    }

    public void   rLoadHistory  (Rengine re, String filename) {
    }           

    public void   rSaveHistory  (Rengine re, String filename) {
    }           
}

public class rtest2 {
    public static void main(String[] args) {
        System.out.println("Press <Enter> to continue (time to attach the debugger if necessary)");
        try { System.in.read(); } catch(Exception e) {System.out.println("Exception"+e.toString());}
        System.out.println("Creating Rengine (with arguments)");
        Rengine re=new Rengine(args, true, new TextConsole2());
        System.out.println("Rengine created, waiting for R");
        if (!re.waitForR()) {
            System.out.println("Cannot load R");
            return;
        }
        System.out.println("re-routing stdout/err into R console");
        System.setOut(new PrintStream(new RConsoleOutputStream(re, 0)));
        System.setErr(new PrintStream(new RConsoleOutputStream(re, 1)));

        System.out.println("Letting go; use main loop from now on");
    }
}