Hello to you all,
First of all, I apologise for submitting this post for the second time, but
the first didn't use the correct user group.
I'm adding a new feature to a Wicket application that manages
JEE-applications (I'm using 1.4.18). For example, it's possible to install
and configure a JEE-appliation on an Application server. If a user chooses
to do so, he enters a unique application code and submits: a zipfile
containing the application, it's documentation and configuration is
downloaded via http from a Nexus repository, and installed with
soap/jmx/mbeans on the application server.
What I have added, is a button that - once clicked - opens an installation
manual in msword that is part of the aforementioned zipfile. The general
idea is: take a zipinputstream, read it until the installation manual is
found, then hand the inputstream over to a wicket IResourceStream that
provides the getInputStream for a Wicket WebResource. I think it's a quite
elegant solution; it's all streaming, no temporary files etcetera.
And it works marvelously, that is, if the zipfile actually containes a
installation manual. My problem is twofold:
When pressing the button without entering an application code (so there is
no inputstream and no installation manual) wicket produces:
org.apache.wicket.WicketRuntimeException: Could not get resource stream
at org.apache.wicket.Resource.init(Resource.java:217)
at org.apache.wicket.Resource.onResourceRequested(Resource.java:117)
at
org.apache.wicket.markup.html.link.ResourceLink.onResourceRequested(ResourceLink.java:108)
... 36 more
That's to be expected, but the user is confronted with a white screen, and I
can't catch this Exception.
Secondly, if there is a zipinputstream, but no installation manual found in
it, all I can do is throw a ResourceStreamNotFoundException (see my code
below), but then again, I can't catch it, and again there is a white screen
for the user.
What is need, I think, is to override onResourceRequested() in Resource, but
that is a final method... And the onclick happens after
onResourceRequested()...
So what I want, is to handle the ResourceStreamNotFoundException in a
user-friendly way, by showing an info or error message in the wicket
feedbackpanel.
The code:
(So the user enters an application code an presses the new button:)
<td><input type="button" wicket:id="downloadinstallationmanual"
value="Download Installatiehandleiding" /></td>
The button is counterparted by a ResourceLink in a Wicket-Form:
private Link<String> downloadInstallationmanualButton = null;
...
final InstallationManualWebResource installationManualWebResource = new
InstallationManualWebResource(this);
installationManualWebResource.setCacheable(false);
downloadInstallationmanualButton = new
ResourceLink<String>("downloadinstallationmanual",
installationManualWebResource);
downloadInstallationmanualButton.setOutputMarkupId(true);
add(downloadInstallationmanualButton);
The above mentioned
InstallationManualWebResource is a subclass of WebResource, and overrides
the usual methods:
@Override
public IResourceStream getResourceStream() {
installationManualResourceStream = new
InstallationManualResourceStream(getZipInputStream());
return installationManualResourceStream;
}
@Override
protected void setHeaders(WebResponse response) {
super.setHeaders(response);
if (installationManualResourceStream.getInstallatieHandleidingName()
!= null)
response.setAttachmentHeader(installationManualResourceStream.getInstallatieHandleidingName());
}
At it's turn InstallationManualResourceStream implements IResourceStream:
In it's constructor, the zipinputstream is read until an installation manual
is found. If so, a boolean installationManualFound is set to true, and
file-attributes are set (name, size, time). The implementation is
straightforward:
@Override
public void close() throws IOException {
zipFile.close();
}
@Override
public String getContentType() {
return "application/msword";
}
@Override
public InputStream getInputStream() throws
ResourceStreamNotFoundException {
if (!installationManualFound) throw new
ResourceStreamNotFoundException("No installation manual in zipfile");
return zipFile;
}
@Override
public Locale getLocale() {
return new Locale("nl", "NL");
}
@Override
public long length() {
return size;
}
@Override
public void setLocale(Locale locale) {
}
@Override
public Time lastModifiedTime() {
return Time.milliseconds(time);
}
--
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