import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.StringWriter;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.python.core.PyCode;
import org.python.core.PyException;
import org.python.core.PyObject;
import org.python.jsr223.PyScriptEngine;
import org.python.jsr223.PyScriptEngineFactory;
import org.python.util.PythonInterpreter;

public class JythonWindow {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Display display = new Display();

        Shell shell = new Shell();
        shell.setText("Enter your Jython code!");
        shell.setLayout(new FillLayout());

        final Text textArea = new Text(shell, SWT.MULTI | SWT.BORDER | SWT.WRAP | SWT.V_SCROLL);
        final Button button = new Button(shell, SWT.PUSH);
        final Label label = new Label(shell, SWT.PUSH);

        textArea.setLayoutData(new GridData(GridData.FILL_BOTH));
        button.setText("Evaluate!");
        button.addListener(SWT.Selection, new Listener() {
            public void handleEvent(Event e) {
                switch (e.type) {
                case SWT.Selection:
                  String result = evaluateJython(textArea.getText());
                  label.setText("Jython's script result is:\n" + result);
                  break;
                }
            }
        });

        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {

                display.sleep();
            }
        }
        display.dispose();

    }

    protected static String evaluateJython(String script) {
        try {
            PythonInterpreter interop = new PythonInterpreter();
            PyCode code = interop.compile(script);
            PyObject result = interop.eval(code);
            return result.toString();
        } catch (Throwable e) {
            StringWriter sw = new StringWriter();
            PrintWriter pw = new PrintWriter(sw);
            e.printStackTrace(pw);
            return sw.toString();
        }
    }

}