Re: Data Table Sorting still not working

[Mike]

Hi Simon, This is great info, thanks. You should write a "how to" book on MyFaces (we could use it! <s>). I seem to have things set up  the way you're describing, so I'm wondering if my faces-config is missing some listener or something since clicking the header doesn't actually fire the setSortColumn() method in my managed bean (the getSortColumn() does fire, but that's part of the normal startup). I'm going to try and get the source example working and I'll report back later on. Thanks again!!!!     Mike Simon Kitching wrote: Hi Tom/Mike, The "sortColumn" attribute on the <t:dataTable> tag points to a javabean *property* of type String. eg:   <t:dataTable     value="#{mybean.dataToDisplay}     sortColumn="#{mybean.sortByColumn}" .../> where the managed bean declaration maps name "mybean" to an instance of MyBean which has:   public class MyBean {     private String sortCol;     public void setSortByColumn(String columnName) {         this.sortCol = columnName;     }     public String getSortByColumn() {         return this.sortCol;     }     public List getDataToDisplay() {         // get the data to display from wherever is appropriate         // sort it according to the current value of this.sortCol         // return the list     }   } Each <t:commandSortHeader> tag has a "columnName" attribute. When the user clicks on that column, the page is submitted. The commandSortHeader looks into its parent t:dataTable to find the "sortColumn" EL _expression_ it assigns to, rather than requiring the mapping to be defined on each and every commandSortHeader tag. In this example, it finds "#{mybean.sortByColumn}" so ends up passing the columnName value for the clicked-on header to method MyBean.setSortByColumn [1]. The commandSortHeader then forces processing to jump to the rendering phase immediately (it is an IMMEDIATE component by default), at which point the dataTable then fetches its "value", ie calls method getDataToDisplay. The table is then re-rendered using this data list and the user sees the new table, in the new order. [1] Model properties aren't normally updated during the "validation" phase. However some special-case code does this for the sortColumn property because the commandSortHeader is usually immediate yet the method that returns the data (getDataToDisplay in this example) needs to know that value. The setSortByColumn method should therefore be called once each time a click on a sortable header occurs. I don't know whether the getSortByColumn method is ever called; it *might* be needed in order to know which column to render the arrow on, or maybe that's figured out in some other way in which case it might not be called at all. I don't know what the '#' is doing on the end of your URL, but I don't think it's important. That's just an "anchor" identifier in HTML terms, and shouldn't be significant in this case. You can always see the latest source code here:   http://svn.apache.org/repos/asf/myfaces/examples/trunk/simple/ see especially the "src" subdirectory. A "managed bean" and a "backing bean" are really the same thing. Technically, there is no such thing as "a backing bean" in JSF, as each component in a page can map to a different bean if it wants. However in practice most/all components on a page map to the same bean (ie have the same bean name for all #{beanname.zzzzz} expressions), so referring to that bean as "the backing bean for the page" is common. And technically that bean does not *have* to be a managed bean (ie an instance defined in the <managed-bean> config tags) - though in practice almost all the time this *is* how beans referenced from a page are defined. Regards, Simon Mike wrote: Hi Tom, The way I understand it is that the sort() method gets called automatically when you define your data table with an entry like this: sortColumn="#{list.sort}" (you have to have, in this case, a sort property with a getter/setter in whatever class the list managed bean points to) (per the sortTable.jsp example with the MyFaces source code). So the list.sort, as I understand it, is the sort property in the list class (or whatever class it really is based on faces-config). Then, as I understand it, the <t:commandSortHeader...> will (somehow) send the value (what you've defined in the columnName) into the list class (in the above example and also magically call the sort() method based on the sortColumn you defined. This is the magical part that doesn't work for me at all. So, I'm clearly not understanding ... SOMETHING! I can match what I've done almost method for method, property to property, to the "SimpleCarSort" in the example source. Maybe I haven't configured something in faces-config.xml correctly -- maybe I need another listener? I really don't know. Tomorrow I'm going to try to get the example one working from the source locally (the car type/color) example. That may help validate I'm OK or there's some wacky configuration problem. Frustrating? Yup, I've spent two full days just trying to get the click of the header to actually do something. My URL also gets a "#" when I click the column appended to the end. I have no idea what that signifies. But, if I manually remove it, I see that the sort code runs but ALWAYS on the initial sort column -- nothing to do with me clicking a particular colulmn. My up arrow is always pointed down and it always stays on the first column even when I click the second "sortable" column. Also, my getSortColumn() never gets called. I have a managed bean, but the posts talk about a "backing bean". I think this is really the same, but, yet another question mark. Sigh.... I'll write again tomorrow with my results from running, 'er, attempting to run, the source example. Write with any results you get too.     Mike ------------------------------------------------------------------------ Tom Butler wrote: Mike – are you calling the sort method from within your getUpdates getter method in your bean (I’m assuming Updates is your arraylist/datamodel since you have value ="#{TD.updates}" ?   Note I’m not sure if this is needed or not – you are ahead of where I am with regards to getting this working  – I’m still working on understanding how to implement this;  The reason I’m asking about including the sort in the getter method is because of a response I received from another mail list (mistakedly sent this to the dev mail list earlier):   “-----Original Message----- From: Thomas Spiegl [mailto:[EMAIL PROTECTED]] Sent: Thursday, December 29, 2005 6:02 AM To: MyFaces Development Subject: Re: Tomahawk DataTable Sort Question - where/how is Sort Coded?   Sort your data in getArrlist_providers depending on the values of sortcol and sortascending. Collections.sort(arrlist_providers, YourComparator) may sort the list. ”   Also, here is another example I just found that shows calling the sort within the getter method: http://mail-archives.apache.org/mod_mbox/myfaces-commits/200505.mbox/[EMAIL PROTECTED]   One good working example end-to-end (complete code) would be very helpful.  The link above is the closet I have found, however, I’m still deciphering it – for example, sort(getsortt(), getascending()) – I’m not sure what the getsort() actually calls or resolves to?     Thanks Tom                         ------------------------------------------------------------------------ *From:* Mike [mailto:[EMAIL PROTECTED]] *Sent:* Friday, December 30, 2005 4:23 PM *To:* MyFaces Discussion *Subject:* Data Table Sorting still not working   Hi Geeta , (Sorry I got your name wrong before....) Below was a typo. Sorry. It should have been Persons, not getPersons. I tried to replace TD with a longer name but that didn't help. I'm baffled. The "hard" stuff, the programming, is so easy compared to just "hooking up" the Data Table component. I've now spent another day on this and have gotten nowhere. For some reason, the commandSortHeader is just not working. I've also tried to download a fresh "myfaces-all.jar" in case that was it. And, I've tried to disable my firewall software. No dice. When I compare the sample to what I have, they seem identically set up. Of course, I can't yet verify the sample would run here either. I suppose what I'll need to do is get the example installed an working. I'm afraid that will be as difficult as what I'm facing now with all the config file tweaks and such. Thanks very much for your help!!!     Mike [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> wrote: Mike <[EMAIL PROTECTED]> <mailto:[EMAIL PROTECTED]> wrote on 12/30/2005 12:36:39 PM: > Hi Gretta! > > Thanks for your reply. > Please see my comments in-line below.... > > Mine is:  value ="#{TD.getPersons}"  > Shouldn't you simply have "#{TD.persons}" ? Here's what i have: <t:dataTable id="contactsearchdata" styleClass="scrollerTable"         headerClass="standardTable_BgWhiteHeader"         footerClass="standardTable_Header"         rowClasses="standardTable_Row1,standardTable_Row2"         columnClasses="standardTable_ColumnCentered,standardTable_Column,standardTable_Column,standardTable_ColumnCentered,standardTable_ColumnCentered,standardTable_ColumnCentered"         var="contact"       value="#{search.matchingContacts}"         rows="7"         rowId="#{contact.id}"         sortColumn="#{search.sort}"         sortAscending="#{search.ascending}"         preserveSort="true"> Also, if all else fails, try replacing your name "TD" with something else. I remember (though this was a long time ago!) short names which were capitalised created trouble with reflection.. > > > Strange, huh? > >     Mike Regards, Geeta (..umm.. not "Gretta" ;))