How To Use Rcaller with Java Servlet and read CSV file

Question

I'm using R programing to analysis FFT . now I want to make Java web application/ java servlet and calling R to use Rcaller/Rcode for it . I have some reference about Calling Rcode in java application. http://code.google.com/p/rcaller/wiki/Examples I have CSV File for example A.csv
time Amplitude
1 0.00000 -0.021
2 0.00001 -0.024
3 0.00003 -0.013
4 0.00004 -0.023
5 0.00005 0.019
6 0.00007 -0.002
7 0.00008 -0.013
then I want to upload this file and use R Code for analysis FFT and Plot it. Help is much appreciated! Thanks in advance, Maria

Answer 1

You start creating an instance of RCaller and set the current location of install Rscript.exe file. You can start with

RCaller caller = new RCaller();
Globals.detect_current_rscript();
caller.setRscriptExecutable(Globals.Rscript_current);
RCode code = new RCode();

or you can give the exact location

RCaller caller = new RCaller();
caller.setRscriptExecutable("c:\\path\\to\\Rscript.exe");
RCode code = new RCode();

Suppose your data is saved in a file mydata.csv.

code.addRCode("dat <- read.cvs(\"mydata.csv\", header=T, sep=\",\"");

then we are plotting the Amplitude

File file = code.startPlot();
code.addRCode("plot.ts(dat$Amplitude)");
code.endPlot();

and sending our code to R:

caller.setRCode(code);
caller.runOnly();

And now, the file variable holds the image data. It can be shown on screen using the code

code.showPlot(file);

For further reading, follow the blog entries on stdioe blog

Answer 2

When I execute this code is running but didn't show anything !!!!!!!

package test2;

import java.io.File;
import java.io.IOException;
import java.util.Random;
import javax.swing.ImageIcon;
import rcaller.RCaller;
import rcaller.RCode;
import rcaller.exception.RCallerExecutionException;
import rcaller.exception.RCallerParseException;

public class Test2 {
public static void main(String[] args) {
Test2 test2=new Test2();

}
 private int span;
 @SuppressWarnings("empty-statement") 


 public void test2()throws IOException{
  try {

  RCaller caller = new RCaller();
  caller.setRscriptExecutable("C:\\Program Files\\R\\R-3.0.3\\bin\\Rscript.exe");
  RCode code = new RCode();

  code.addRCode("dat<-read.csv(\"NetBeansProjects\"test2\"A.csv\",header=T,sep=\",\"");

  File file=code.startPlot();
  code.addRCode("plot.ts(dat$Amplitude)");
  code.endPlot();

  caller.setRCode(code);
  caller.runOnly();
  ImageIcon i=code.getPlot(file);
  code.showPlot(file);

} catch (RCallerExecutionException | RCallerParseException e) {
  System.out.println(e.toString());
}

 } 

 }