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();
		}		
	}

}