Daniel, I think your approach is ok. But... why do you need some
properties-file? You can just extend my class with something like
private boolean _invalidated = true;
public void Invalidate(){
this._invalidated = true;
}
and then in
private DataPage<T> doFetchPage(int startRow, int pageSize){
if ((_lastPage == null) || (_lastStartRow != startRow) ||
(_lastPageSize != pageSize) || _invalidated){
_log.debug("**Fetch: required -> fetching...");
_lastPage = fetchPage(startRow, pageSize);
_lastStartRow = startRow;
_lastPageSize = pageSize;
_invalidated = false;//don't
vorget to set it to FALSE
}else{
_log.debug("**Fetch: not required (already fetched)!");
}
return _lastPage;
}
Just call this Invalidate() method from your bean after making changes,
and the current page becomes refetched during next access at rendering
phase. (It's exactly what you are doing now with the property file :))
The _invalidated flag 'overrides' any other condition and forces the
page to be refetched just once.
Unfortunately I have not enough time right now to explain the approach
in my implementation in detail (because I have to switch to another
nonJSF-project), but I plan to build small example application next
week, you have asked for. It would be nice, if someone be able then to
correct my terrible English and publish it at Wiki...
Just few tips about delete/edit situation:
- If you delete some record, you have to 'reload' at least the total
count value (since the stored in instance of paged list value becomes
incorrect). (The worst case: you land at incorrect page number, if you
delete the only one item being at the LAST page.)
- If you edit something, what (due to your sorting order) can affect
the subset of items being displayed at current page, you have to reload
the page as well. (This can lead into situation, when your just edited
item 'disappears' from the current page.)
regards,
paul
daniel ccss schrieb:
Ok Paul, this is the thing,
Since I´m new in this and in my work they are asking for results from
the Tomahawk investigation that i'm doing implementing a simple
maintain module, I think that I can´t impplement all that you have
done, at least in this moment.
This is what i have done until now, I changed the PagedList class from
the wiki for yours, that was the only class that Ichanged, the other
change was to put the bean in session (Vladimir idea) (by the way nice
tip, you gave for put it in session from code). Until now all works
fine.
Then i made my delete, add and edit methods, they simple recived the
Patient id and call an EJB that calls to the DAOs methods to do that.
They are called from an actionlistener on the JSP. They all works fine,
but I don`t saw the changes on the DataTable, in the moment, but when I
click on the pages numbers I saw the changes.
What I need, is from code, and after call a delte/add/edit method,
fetch the data(as happen when i click on a page number) from my backing
bean, and of course always pass for the filter to do the fetch after
this methods are called, something like:
backing_bean:
public void delete()
...
EJB.deletePatient(...)
fetch data
I made a hardcore test ( I need to do it for test my idea :( ) I made a
properties file, and put a key call forceToFetch = false, and in the
dofetch method I get this property then in your filter (If) I add this:
if(.... || forceToFetch). Inside the if I ask if the forceToFetch is
true and put it again in false in the properties file.Then in the
backing_bean after call the add/delete/edit methods I put the value in
the properties in true, and as I thought it wors fine, I can saw all
the changes on the DataTable. Can you give a way to do this witout use
the properties file? Can you give me an step by step solution since
I`m new in this and I still understanding all your code.
Other thing I see a problem with this solution when I delete the last
row of a DataPage (example the last row of the second DataPage) or when
I delete the last row of the first DataPage, I recived a row index
exception. How can I fix this issue, can you explain me. If I delete
the last row of dataPage 3 how can I show, from code, the dataPage2 and
in the case of the last row of the first DataPage how can I delete that
last row and show the First DataPage without data? Can you also explain
me this step by step?
Paul really really sorry for all this, but I think that your are the
person that more knows of this, you are a Guru on this, and I really
need help, also thanks to you Vladimir!!
On 7/6/07, Paul
Iov <[EMAIL PROTECTED]>
wrote:
Vladimir
Isakovich schrieb:
> Yes, I have just one call getting through to my DB, the session
scoped
> bean with Paul's blocking method worked. The drawback with this
> approach, we may start thinking on cleaning session off of the
unused
> objects, otherwise our app may consume too much cache on the
server.
>
> vlad
That's why I don't utilize the JSF backing bean facility. It's not
flexibly enough to maintain high dynamically applications.
I've implement own session controller and it's the only backing bean I
have to declare in my faces-config.xml ;) The other part of magic is
application wide controller (started with ServletContextListener) to
maintain some global issues and, first of all the sessions, which I
catch with HTTPSessionListener.
Just a little hint: you can 'inject' your beans into session without
declaring it in config.
<managed-bean>
<managed-bean-name>MyBean</managed-bean-name>
<managed-bean-class>my.MyClass</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>
is equal to:
FacesContext fCtx = FacesContext.getCurrentInstance();
ExternalContext eCtx = _fCtx.getExternalContext();
ServletContext srvCtx = (ServletContext)_eCtx.getContext();
HttpSession session = (HttpSession)_eCtx.getSession(false);
...
MyClass myInstance = new MyClass();
session.setAttribute("MyBean", myInstance);//put MBean to session
|
