Think I've cracked it - can't believe there're only two of us that have
seen this.
The problem appears to be that my data table doesn't have a fixed number
of rows and until some action has been performed will contain zero rows.
My page has a search form, and the table shows the results of a search.
On initial navigation to the page the search results are empty. My table
is bound to "customers" value - here's the getter foe my table's rows:
public DataModel getCustomers() {
logger.debug("get customers called: customers = " +
customers);
Exception e = new Exception("Fake exception");
logger.debug("", e);
ListDataModel model = new ListDataModel();
if (customers == null) {
customers = new ArrayList<Customer>(0);
}
model.setWrappedData(customers);
return model;
}
The search button on the page is bound to the search action in my
bean...
public void search() {
logger.debug("search called");
String v_email = (getEmail() != null) ? getEmail() : ""
;
String v_screenName = (getScreenName() != null) ?
getScreenName() : "" ;
String v_firstName = (getFirstName() != null) ?
getFirstName() : "" ;
String v_lastName = (getLastName() != null) ?
getLastName() : "" ;
customers = customerManagement.listCustomers(
v_email, v_screenName, v_firstName,
v_lastName);
if ( customers == null || customers.size() == 0 ) {
String message = (String)
getMessages().getMap().get(NO_RESULTS);
getFacesContext().addMessage(null, new
FacesMessage(message));
}
}
So until the search button is pressed my table data is empty.
Ok. So the secret of the failure lies in when the getter is called and
by what. The lifecycle of the page is:
1. ==== initial navigation =====
Bean created, getCustomers() called during render response phase
when table is rendered. Returns an empty list.
2. ==== search performed: users fills in a field value and hits search.
=====
getCustomers() called twice.
First call: apply request values phase. Called because UIData
fires UIData.setRowIndex(). Returns empty list.
Second call: render response phase. Called when table is
rendered. Search() has been called now (during invoke app phase) so
getCustomers() returns a list with (for example) two rows.
3. ==== user details accessed: user clicks the actionlink in the first
row of the table ============
getCustomers() called twice.
First call: apply request values phase. Called because UIData
does a UIData.setRowIndex(). Customers is null as no search has been
performed.
Second call: render response phase. Called when table is
rendered. No search() performed so getCustomers() returns a empty list.
The key is in the first call to getCustomers() during the third
navigation. The stack trace when that call is made is...
java.lang.Exception: Fake exception
at
myclass.UserSearchViewController.getCustomers(UserSearchViewController.j
ava:103)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.jav
a:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
Impl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at
org.apache.myfaces.el.PropertyResolverImpl.getProperty(PropertyResolverI
mpl.java:400)
at
org.apache.myfaces.el.PropertyResolverImpl.getValue(PropertyResolverImpl
.java:71)
at
org.apache.shale.faces.ShalePropertyResolver.getValue(ShalePropertyResol
ver.java:137)
at
org.apache.myfaces.el.ELParserHelper$MyPropertySuffix.evaluate(ELParserH
elper.java:532)
at
org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:145)
at
org.apache.myfaces.el.ValueBindingImpl.getValue(ValueBindingImpl.java:37
8)
at javax.faces.component.UIData.getValue(UIData.java:779)
at javax.faces.component.UIData.createDataModel(UIData.java:545)
at javax.faces.component.UIData.getDataModel(UIData.java:534)
at javax.faces.component.UIData.setRowIndex(UIData.java:147)
at
javax.faces.component.UIData.processColumnChildren(UIData.java:477)
at javax.faces.component.UIData.processDecodes(UIData.java:381)
...
One of the things that happens in processDecodes() is that any
ActionEvents are queued for later invocation. We have fired an action
event on the table by clicking on a row's commandLink. However, because
the call to getCustomers() returns an empty list, the UIData component
believes that the table had no rows. It therefore stops processing the
table at that point so the commandLink action event is never
queued!!!!!!
As far as JSF is now concerned, no event happened. It therefore defaults
to re-rendering the same page.
The problem now is how do I fix it? Well I've fixed it by making my bean
session scoped so that the value of customers is preserved across
requests. Then the first call to getCustomers() returns it's value at
the previous page rendering. Maybe someone can tell me if there's some
cleverer fix than that - maybe using phase listeners or something?
Is it a bug? I think so. It seems to me that UIData relying on the
request-scoped backing bean to tell it how many rows the table has is
incorrect; there is an assumption there that the call to getValue() will
always return the same result. Sounds like a bug to me. What do the
community think?
BTW, Thanks Ryan for your response. Knowing I wasn't the only one seeing
this behaviour motivated me to take a deeper look!! I guess your stuff
fails because when you move your data connection to prerender() the
first call to your getter is returning an empty list.
Cheers,
Ian.
-----Original Message-----
From: Ryan [mailto:[EMAIL PROTECTED]
Sent: 05 May 2006 06:48
To: Struts Users Mailing List
Cc: Ian.Priest
Subject: Re: [shale][clay] commandLink in dataTable not working
I'm experiencing the same behavior, and I've built all my views in Clay
as well. Here's an interesting behavior that I see in my Controller
(extending the Shale Controller).
I have Page A that displays a data table with image links throughout
that link to an action, let's call it "edit". This is backed by a
managed PageAViewController. If I put the following calls in init():
- a call to the spring-jsf resolver to get my service object
- make the service object call (underlying is a Hibernate call) then,
Page A displays the data table, and the link action method is called and
I'm brought to Page B.
Now, if I move the service object Hibernate call to prerender() in
PageAViewController (where I think it should be), the data table is
still displayed, but this time, when I click on any of the links, the
link action method is never called, and the page is redisplayed. I
can't figure out what I'm doing wrong for the life of me, seems like
everything should work.
I've even added the immediate="true" as Gary suggested, but that doesn't
help to any avail. I find it interesting that if all the calls are
init(), I get the right page, but I don't want to make the Hibernate
data call all the time. Anyone else seen this? Anybody have any
debugging tips?
_RK
On 5/4/2006, "(Gary VanMatre)" <[EMAIL PROTECTED]> wrote:
>
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