R from within Java

Question

What's the best way to call R functionality from within Java?

I'm looking for a quick, easy and reliable way to make standard 2d scatter plots and histograms in R using my Java applications. I was wondering which packages/interfaces that came up in a quick Google search would be most convenient to use.

I look forward to your suggestions!

Duplicate: http://stackoverflow.com/questions/1136709/extend-my-java-application-with-r — Shane, Feb 01 '10 at 21:43

Shane · Accepted Answer · 2010-02-01T22:04:15.953

Use JRI: http://www.rforge.net/JRI/. It comes bundled with rJava, including some examples of usage.

A very simple example would be like this:

import java.io.*;
import java.awt.Frame;
import java.util.Enumeration;

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

public class rJavaTest {

    public static void main(String[] args) {

        Rengine re=new Rengine(args, false, new TextConsole());
        REXP x;
        re.eval("print(1:10/3)");
        System.out.println(x=re.eval("iris"));
        RVector v = x.asVector();
        if (v.getNames()!=null) {
            System.out.println("has names:");
            for (Enumeration e = v.getNames().elements() ; e.hasMoreElements() ;) {
                System.out.println(e.nextElement());
            }
        }

        if (true) {
            System.out.println("Now the console is yours ... have fun");
            re.startMainLoop();
        } else {
            re.end();
            System.out.println("end");
        }
    }
}

where did you get the TextConsole() you passed as a parameter to Rengine from? I cannot compile this program because of it. — Alex Burdusel, Jan 14 '13 at 18:59
I don't think an incomplete example (without needed `import` statements) should be selected as an accepted answer. @Shane: if you can, fill the gaps of the example you provided. — Giupo, Jul 31 '17 at 15:12
JRI has an `examples` sub-directory where you can see more complete examples. In `rtest.java` you will find the above with a lot of extra stuff and also find the missing `class TextConsole implements RMainLoopCallbacks{...}` — RolandASc, Feb 16 '18 at 10:06

score 4 · Answer 2 · answered Jul 06 '14 at 07:32

4

There is something new called http://www.renjin.org/

One thing i like it over JRI is deployment, While jri required that your application users will download R, renjin does not, and it uses only the JVM to run.

answered Jul 06 '14 at 07:32

Yehoshaphat Schellekens

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score 2 · Answer 3 · answered Feb 01 '10 at 22:05

2

I have found that forking R as a process, attaching to the process's stdin, stdout, and stderr streams, and sending R commands via the input stream to be quite effective. I use the filesystem to communicate between R and my Java process. This way, I can have multiple R processes running from different threads in Java and their environments do not conflict with each other.

answered Feb 01 '10 at 22:05

AnthonyF

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You can have multiple instances of JRI running in separate threads and there will be no conflict. – Shane Feb 01 '10 at 22:11
Rcaller already performs these operations in a more efficient way. – jbytecode Oct 01 '18 at 18:47

score 2 · Answer 4 · answered Oct 15 '18 at 09:14

FastR is a GraalVM based implementation of R. Embedding it in a JVM application is as simple as:

Context ctx = Context.newBuilder("R").allowAllAccess(true).build();
ctx.eval("R", "sum").execute(new int[] {1,2,3});

For your concrete example, this example plots a scatter plot using the lattice R package, but the output is drawn into Graphics2D object.

    Context context = Context.newBuilder("R").allowAllAccess(true).build();
    // This R function opens FastR graphics device passing it Graphics2D object,
    // then it plots the graph and closes the device
    String src =
        "library(grid); library(lattice); " +
        "function(graphics, width, height, x, y) { " +
        "   awt(width, height, graphics);" +
        "   print(xyplot(as.vector(x) ~ as.vector(y)));" +
        "   dev.off();" +
        "}";
    Value showPlot = context.eval("R", src);

    // Create a BufferedImage to use for the plotting
    BufferedImage image = new BufferedImage(WIDTH, HEIGHT, TYPE_INT_RGB);
    Graphics2D graphics = (Graphics2D) image.getGraphics();
    graphics.setBackground(new Color(255, 255, 255));
    graphics.clearRect(0, 0, WIDTH, HEIGHT);

    // Invoke R plotting code and pass it graphics object
    double[] x = new double[] {1.,2.,3.,4.};
    double[] y = new double[] {1.,2.,3.,4.};
    showPlot.execute(graphics, WIDTH, HEIGHT, x, y);

There is also an example that shows the plots inside a Swing window.

You can find more details about FastR in this medium post: https://medium.com/graalvm/faster-r-with-fastr-4b8db0e0dceb

score 1 · Answer 5 · answered Jun 08 '18 at 09:50

1

Packages or libraries for R with Java

Call R from Java

RCaller
Rserve
JRI
Rsession
Renjin

Call Java from R

rJava

answered Jun 08 '18 at 09:50

mingxue

671
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R from within Java

5 Answers5

Linked