RBase.java

package rJava;

import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;

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

abstract class RBase extends JPanel implements Runnable {
	protected Rengine _engine;
	protected Thread _thread;
	protected boolean _loopFlag = true;
	private boolean _lockFlag = false;
	private File _file;

	public RBase() {
		_engine = new Rengine(new String[] {
			"--no-save"
		}, false, null);
		init();
		_file = paintIMP();
	}

	abstract void init();

	abstract void plot();

	abstract void step();

	protected REXP eval(String cmd) {
		return _engine.eval(cmd);
	}

	@Override
	public void paintComponent(Graphics g) {
		super.paintComponent(g);
		if (_file != null) {
			try {
				BufferedImage img = ImageIO.read(_file);
				g.drawImage(img, 0, 0, this);
			} catch (Exception e) {
				e.printStackTrace();
				_file.delete();
				_file = null;
			}
		}
		_lockFlag = false;
	}

	private File paintIMP() {
		File file = null;
		try {
			file = File.createTempFile("plot", ".png");
			file.deleteOnExit();
			_engine.eval("png('" + file.getAbsolutePath() + "')");
			plot();
			_engine.eval("dev.off()");
			return file;
		} catch (Exception e) {
			if (file != null) {
				file.delete();
				file = null;
			}
			return null;
		}
	}

	protected void toggle() {
		if (!(_thread != null && _thread.isAlive()))
			start();
		else
			_loopFlag = false;
	}

	protected void start() {
		if (_thread == null || !_thread.isAlive()) {
			_thread = new Thread(this);
			_loopFlag = true;
			_thread.start();
		}
	}

	protected void stop() {
		_loopFlag = true;
	}

	protected void reset() {
		_loopFlag = true;
		init();
		_file = paintIMP();
		repaint();
	}

	protected void quit() {
		stop();
		if (_engine != null && _engine.isAlive())
			_engine.end();
	}

	@Override
	public void run() {
		try {
			while (_loopFlag) {
				_lockFlag = true;
				repaint();
				do {
					Thread.sleep(10);
				} while (_lockFlag);
				step();
				_file = paintIMP();
			}
		} catch (Exception e) {
			e.printStackTrace();
			_engine.end();
		}
	}

	public static void show(RBase p) {
		System.out.println("R_HOME:" + System.getenv("R_HOME"));
		System.out.println("java.library.path:"
				+ System.getProperty("java.library.path"));

		JFrame f = new JFrame();
		f.getRootPane().setContentPane(p);
		f.addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				p.quit();
				System.exit(0);
			}
		});
		f.setSize(480, 500);
		f.setVisible(true);
	}
}