Hello,
I'm using myfaces, Trinidad (snapshot M1) and facelets on a tomcat 5.5
webserver.
Because I'm not sure if this is a MyFaces or a Trinidad issue I write on both
lists.
On one of my pages I have an <tr:selectOneChoice> to set an filter on a list of
datas. Below it I have a <tr:table> to display the data itself. In the table
there are download-links (<tr:commandLink>) for every row in the table.
All works fine: setting the filter, displaying the table and downloading the
data via the link.
But if I first download data and than change the filter, the action from the
download link is called again (the valueChangeListener is called, too)
Here are some code snippets:
//facelet file
<tr:selectOneChoice label="select filter"
id="event" autoSubmit="false" onchange="submit()"
valueChangeListener="#{dataBean.filterChangeEvent}">
<f:selectItems value="#{globalProperties.filterTypes}" />
</tr:selectOneChoice>
<tr:table value="#{dataBean.dataList}" var="data">
<tr:column>
<f:facet name="header">
<tr:outputText value="#{id}" />
</f:facet>
<tr:outputText value="#{data.id}" />
</tr:column>
// (some more columns)
<tr:column>
<f:facet name="header">
<tr:outputText value="data" />
</f:facet>
<tr:commandLink text="download}">
<tr:setActionListener //only used to get the
correct id from what to download
from="#{data.id}"
to="#{dataBean.downloadId}" />
<f:actionListener
type="de.tccproducts.dprs.basicstats.DataBean" />
</tr:commandLink>
</tr:column>
</tr:table>
//action Listener methods
public void processAction(ActionEvent event)
throws AbortProcessingException {
// get the current data Object
Data data = getData();
// get the byte array that should be downloaded
byte[] data = data.getByteData();
// set mime type and filename
FacesContext context = FacesContext.getCurrentInstance();
HttpServletResponse response = (HttpServletResponse)
context.getExternalContext().getResponse();
response.setContentType("text/plain");
response.setHeader("Content-Disposition",
"attachment;filename=\"someTestFile.txt\"");
// append the byte[] to the response
ByteArrayInputStream fis = new ByteArrayInputStream(data);
try {
OutputStream os = response.getOutputStream();
int read = 0;
byte[] bytes = new byte[1024];
while ((read = fis.read(bytes)) != -1) {
os.write(bytes, 0, read);
}
os.flush();
os.close();
} catch (Exception ex) {
ex.printStackTrace();
}
FacesContext.getCurrentInstance().responseComplete();
}
public void filterChangeEvent(ValueChangeEvent ev) {
// get the selected value from selectOneChoice
String key = ev.getComponent().getAttributes().get("id").toString();
FilterType filter = (FilterType)
ev.getComponent().getAttributes().get("value");
// set the filter and update the dataList
setFilter(filter);
}
My thought is that the commandLink sets some hidden input fields to say the
server what to download. The download is done but the page is not reloaded and
so the hidden input fields stay as they are.
When the valueChangeListener is called, the Server recognises the hidden fields
again, and so executes the commandLink Action again.
What can I do to avoid this?
Force a refresh on the page after download is done?
Reset the hidden input fields in some way?
Check in the download action if it really should be executed?
Or is there some other problem I don't see at the moment?
Please help if you have an idea on this.
Greetings
Markus
