swt controls里的控件list

swt controls里的控件list，怎么显示滚动条，并且滚动条自动移动到最下边时，显示最新内容

 1 package com.jokul;
 2
 3 import org.eclipse.swt.widgets.Display;
 4 import org.eclipse.swt.widgets.Shell;
 5 import org.eclipse.swt.SWT;
 6 import org.eclipse.swt.widgets.Label;
 7 import org.eclipse.swt.widgets.List;
 8 import org.eclipse.swt.widgets.ScrollBar;
 9
10 public class ListTest {
11
12     protected Shell shell;
13     protected static List list;
14
15     /**
16      * Launch the application.
17      * @param args
18      */
19     public static void main(String[] args) {
20         try {
21             ListTest window = new ListTest();
22             window.open();
23         } catch (Exception e) {
24             e.printStackTrace();
25         }
26     }
27
28     /**
29      * Open the window.
30      */
31     public void open() {
32         Display display = Display.getDefault();
33         createContents();
34         shell.open();
35         shell.layout();
36         while (!shell.isDisposed()) {
37             if (!display.readAndDispatch()) {
38                 display.sleep();
39             }
40         }
41     }
42
43     /**
44      * Create contents of the window.
45      */
46     protected void createContents() {
47         shell = new Shell();
48         shell.setSize(450, 300);
49         shell.setText("SWT Application");
50
51         list = new List(shell, SWT.BORDER | SWT.V_SCROLL);
52         list.setItems(new String[] {});
53         list.setBounds(10, 35, 414, 217);
54
55         Label label = new Label(shell, SWT.NONE);
56         label.setBounds(10, 10, 343, 17);
57         label.setText("\u6F14\u793A\u6EDA\u52A8\u6761\u600E\u4E48\u79FB\u52A8\u5230\u6700\u4E0B\u8FB9\u7684");
58
59         for(int i = 0; i < 100; i++) {
60             showInList("info:" + i);
61         }
62     }
63
64     /**
65      * 在swt的list上显示信息
66      * @param str
67      */
68     private static void showInList(final String str){
69         Display.getDefault().asyncExec(new Runnable() {
70             public void run() {
71                 list.add(str);
72
73                 int count = list.getItemCount();
74                 list.setSelection(count - 1);
75
76                 ScrollBar sb = list.getVerticalBar();
77                 if(sb !=null && sb.isVisible()) {
78                     sb.setSelection(sb.getMaximum());
79                 }
80             }
81         });
82
83     }
84 }