SWT: Periodically update GUI

[Jase]

I have an SWT GUI which displays a list taken from a database. What I would like for it to do is to periodically update the GUI, which would involve clearing everything in the shell and running the populateList() method again. I have tried several suggested strategies for this, but the GUI never updates. My latest attempt is using display.asyncexec to create a thread to handle this. This appears to give me an invalid thread access error. Here's my code:\[code\]package display;import java.io.IOException;import java.io.StringReader;import java.util.ArrayList;import java.util.Timer;import java.util.TimerTask;import object_models.Request;import util.RestClient.RequestMethod;import org.eclipse.swt.SWT;import org.eclipse.swt.graphics.Color;import org.eclipse.swt.graphics.Font;import org.eclipse.swt.graphics.Image;import org.eclipse.swt.graphics.Point;import org.eclipse.swt.layout.GridData;import org.eclipse.swt.layout.GridLayout;import org.eclipse.swt.layout.RowData;import org.eclipse.swt.layout.RowLayout;import org.eclipse.swt.widgets.Composite;import org.eclipse.swt.widgets.Control;import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Label;import org.eclipse.swt.widgets.Shell;import org.xmlpull.v1.XmlPullParser;import org.xmlpull.v1.XmlPullParserException;import org.xmlpull.v1.XmlPullParserFactory;import util.RestClient;public class StoragePickupDisplay { protected Shell shell; private ArrayList<Request> pendingRequests; /** * Launch the application. * @param args */ public static void main(String[] args) { try { StoragePickupDisplay window = new StoragePickupDisplay(); window.open(); } catch (Exception e) { e.printStackTrace(); } } /** * Open the window. * @throws InterruptedException */ public void open() throws InterruptedException { Display display = Display.getDefault(); createContents(); populateList(); shell.open(); shell.layout(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) { display.sleep(); } display.asyncExec(new Runnable() { public void run() { populateList(); } }); Thread.sleep(1000); } } /** * Create contents of the window. */ protected void createContents() { shell = new Shell(); //shell.setMaximized(true); //shell.setFullScreen(true); shell.setText("Request Pickup"); shell.setMaximized(true); GridLayout gridLayout= new GridLayout(1,false); shell.setLayout(gridLayout); } protected void populateList(){ pendingRequests=new ArrayList<Request>(); RestClient client = new RestClient("http://XXXXXX:8080/StorageWebService/rest/operations/getPendingRequests"); try { client.Execute(RequestMethod.GET); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } String response = client.getResponse(); pendingRequests= parseResponse(response); for(Request request: pendingRequests){ Composite row = new Composite(shell,SWT.NONE); GridLayout gridLayout = new GridLayout(4,true); gridLayout.marginTop=5; row.setLayout(gridLayout); row.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, true, false)); Composite left = new Composite(row,SWT.NONE); left.setLayout(new GridLayout(2,false)); left.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, true, false)); Label label = new Label(left,SWT.LEFT); label.setText(""+request.getId()); label.setFont(new Font(Display.getDefault(),"Arial",30, SWT.NONE)); label.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, false, false)); label = new Label(left,SWT.LEFT); label.setText(request.getNickname()); label.setFont(new Font(Display.getDefault(),"Arial",30, SWT.NONE)); label.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, true, false)); label = new Label(row,SWT.LEFT); label.setText(""+request.getNumberCompleted()+" of "+request.getNumberItems()+" Picked"); label.setFont(new Font(Display.getDefault(),"Arial",30, SWT.NONE)); label.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, true, false)); label = new Label(row,SWT.LEFT); label.setText("Estimated Wait Time:"); label.setFont(new Font(Display.getDefault(),"Arial",30, SWT.NONE)); label.setLayoutData(new GridData(SWT.FILL, SWT.BEGINNING, true, false)); Label separator = new Label(shell, SWT.HORIZONTAL|SWT.SEPARATOR|SWT.PUSH); GridData gridData = http://stackoverflow.com/questions/15710992/new GridData(SWT.FILL, SWT.BEGINNING, true, false); //gridData.horizontalSpan=4; separator.setLayoutData(gridData); } } public ArrayList<Request> parseResponse(String response){ ArrayList<Request> list = new ArrayList<Request>(); try { XmlPullParser parser = XmlPullParserFactory.newInstance().newPullParser(); parser.setInput(new StringReader(response)); int eventType = parser.getEventType(); Request curRequest = new Request(); while (eventType != XmlPullParser.END_DOCUMENT) { if (eventType == XmlPullParser.START_TAG) { String name = parser.getName(); if (name.equalsIgnoreCase("id")) { String text = parser.nextText(); curRequest.setId(Integer.parseInt(text)); } if (name.equalsIgnoreCase("nickname")) { String text = parser.nextText(); curRequest.setNickname(text); } if (name.equalsIgnoreCase("numberCompleted")) { String text = parser.nextText(); curRequest.setNumberCompleted(Integer.parseInt(text)); } if (name.equalsIgnoreCase("numberItems")) { String text = parser.nextText(); curRequest.setNumberItems(Integer.parseInt(text)); } if (name.equalsIgnoreCase("status")) { String text = parser.nextText(); curRequest.setStatus(Integer.parseInt(text)); } } if (eventType == XmlPullParser.END_TAG) { if (parser.getName().equalsIgnoreCase("Request")) { list.add(curRequest); curRequest = new Request(); } } eventType = parser.next(); } } catch (XmlPullParserException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return list; }}\[/code\]