Java Reference
In-Depth Information
adoptsthesizeoftheimageicon'simageasitspreferredsize),thewindowismadenon-
resizable, and the window is displayed.
The
doGet()
methodcreatesa
URL
object,opensanHTTPconnectiontothe
URL
instance,specifies
GET
astherequestmethod,tellstheconnectionthatitonlywantsto
inputcontent,andproceedstoreadthecontentwhentheresponsecodeis200(success).
The content is stored in an array of bytes. If the array is too small to hold all the
content,thearrayisdynamicallyresizedbycreatingalargerarrayandcopyingtheori-
ginalarray'scontenttothenewarraywithhelpfrom
System.arraycopy()
.After
allbyteshavebeenread,thisarrayispassedto
ImageIcon
's
ImageIcon(byte[]
imageData)
constructortostorethePNGimageasthebasisofthe
ImageIcon
ob-
ject, which is returned from
doGet()
.
Ifsomethinggoeswrong,aninstanceofthe
IOException
classoroneofitssub-
classes (such as
java.net.MalformedURLException
, which signifies that the
argument passed to
URL
's constructor is illegal) is thrown. The catch block handles
this exception by invoking
javax.swing.JOptionPane
's
void showMes-
sageDialog(Component parentComponent, Object message,
String title, int messageType)
to display a suitable error message via a
popup dialog box.
ViewChart
).
Figure 11-8
shows the resulting chart.
