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Posted to users@tapestry.apache.org by Ruud Diterwich <rd...@cedron.com> on 2003/06/24 12:30:26 UTC
Service parameters
True, but my problem with that is that the service parameters are like
url parameters, where we wanted to be abstracted away from. Concrete
problem:
I have 2 table components on one page, each with their own page
numbering and current page. If one table is located at page 5, and a
next page on the second table is selected, the original table falls back
to page 1.
So the service parameters introduce a kind of 'global' variable space,
which is not in line with 'component-based' development. Not to mention
the extra burden on the template author, who has to specify the
parameter on each DirectLink tag.
Ruud Diterwich
> -----Original Message-----
> From: Denis Ponomarev [mailto:oz@romsat.ua]
> Sent: Tuesday, June 24, 2003 11:23
> To: Tapestry users
> Subject: Re[2]: Redirects and multiple database fetches
>
> RD> My case is a data table with next and previous buttons. When next
is
> RD> clicked, the data for the next page is fetched from the database.
> RD> Especially these navigation clicks should be fast and waiting for
2
> RD> fetches is annoying.
>
> This is usual navigation actions! :)
>
> I think your 'next' and 'previous' buttons should be DirectLinks with
> parameter 'pageNumber'. No redirection required.
>
> You'll get links like
>
> http://localhost:8081/dmc2?service=direct/1/MyEdit/0/$DirectLink&sp=2
>
> where final '2' is pageNumber.
>
> After refreshing you'll get the same page.
>
>
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> To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
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RE: Re[2]: Service parameters
Posted by Ruud Diterwich <rd...@cedron.com>.
Thanks a lot! Very useful.
Ruud
> -----Original Message-----
> From: Denis Ponomarev [mailto:oz@romsat.ua]
> Sent: Tuesday, June 24, 2003 14:14
> To: Tapestry users
> Subject: Re[2]: Service parameters
>
> RD> My initial attempt was using persistent properties. However, I was
> RD> unable to set a persistent property while rendering. And the value
of
> RD> the persistent property depends on the result of the query that is
> RD> executed in the prepareForRender... (The property must be changed
> (only)
> RD> if the number of result elements is less than a certain value, so
it
> RD> should be persistent).
>
> You can implement PageRenderListener interface in your component.
> It contains of two method, one can be usefull:
>
> public void pageBeginRender(PageEvent event) {
> // here is your final chance to change persistent properties
> // probably this is the place where you should execute query
> // and correct persistent property depending on query result
> }
>
> >> Look:
> >>
> >> <component name="prevLink" type="DirectLink">
> >> <binding name="listener" expression="listeners.changePage"/>
> >> <binding name="parameters" expression="prevPage"/>
> >> <binding name="disabled" expression="first"/>
> >> </component>
> >>
> >> <component name="nextLink" type="DirectLink">
> >> <binding name="listener" expression="listeners.changePage"/>
> >> <binding name="parameters" expression="nextPage"/>
> >> <binding name="disabled" expression="last"/>
> >> </component>
> >>
> >> It assumes that your table component has isFirst(), isLast(),
> >> getNext() and getPrevious() methods based on the currentPage
> >> persistent property.
> >>
> >> And action listener method
> >>
> >> public void changePage(IRequestCycle cycle){
> >> Integer pageNumber = (Integer)
cycle.getServiceParameters()[0];
> >> setCurrentPage(pageNumber.intValue());
> >> }
> >>
> >> RD> the extra burden on the template author, who has to specify the
> >> RD> parameter on each DirectLink tag.
> >>
> >> Template author just locates components:
> >>
> >> <a jwcid="prevLink">previous</a> <a jwcid="nextLink">next</a>
> >>
> >> There is no parameters specification!
> >>
>
> RD> I tend to specify the links directly in the html templates using
> RD> jwcid="@DirectLink". I agree that using the jwc file to specify
> RD> parameters is more puristic.
>
> RD> However, I have a dynamic set of links, one for each page (like
> google)
> RD> of a data set. I have no choice then but to put them directly in
the
> RD> html template:
>
> RD> <span jwcid="@Foreach" value="ognl:navigationPage"
> RD> source="ognl:navigationPages">
>
> RD> <a jwcid="@DirectLink"
listener="ognl:listeners.changePage"
> RD> parameters="ognl:navigationPage">
> RD> <span jwcid="@Insert" value="ognl:navigationPage +
> 1"/>
> RD> </a>
> RD> </span>
>
>
> I think it can be implemented:
> ====================
>
> <component id="everyPage" value="ognl:navigationPage">
> <binding name="source" expression="navigationPages"/>
> <binding name="value" expression="navigationPage"/>
> </component>
>
> <component name="pageLink" type="DirectLink">
> <binding name="listener" expression="listeners.changePage"/>
> <binding name="parameters" expression="navigationPage"/>
> <binding name="disabled" expression="current"/>
> </component>
>
> <component name="pageIndex" type="Insert">
> <binding name="value" expression="navigationPage"/>
> </component>
>
> ====================
>
> <span jwcid="everyPage">
> <a jwcid="pageLink"><span jwcid="pageIndex"/></a>
> </span>
>
> ====================
>
>
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> For additional commands, e-mail: tapestry-user-help@jakarta.apache.org
Re[2]: Service parameters
Posted by Denis Ponomarev <oz...@romsat.ua>.
RD> My initial attempt was using persistent properties. However, I was
RD> unable to set a persistent property while rendering. And the value of
RD> the persistent property depends on the result of the query that is
RD> executed in the prepareForRender... (The property must be changed (only)
RD> if the number of result elements is less than a certain value, so it
RD> should be persistent).
You can implement PageRenderListener interface in your component.
It contains of two method, one can be usefull:
public void pageBeginRender(PageEvent event) {
// here is your final chance to change persistent properties
// probably this is the place where you should execute query
// and correct persistent property depending on query result
}
>> Look:
>>
>> <component name="prevLink" type="DirectLink">
>> <binding name="listener" expression="listeners.changePage"/>
>> <binding name="parameters" expression="prevPage"/>
>> <binding name="disabled" expression="first"/>
>> </component>
>>
>> <component name="nextLink" type="DirectLink">
>> <binding name="listener" expression="listeners.changePage"/>
>> <binding name="parameters" expression="nextPage"/>
>> <binding name="disabled" expression="last"/>
>> </component>
>>
>> It assumes that your table component has isFirst(), isLast(),
>> getNext() and getPrevious() methods based on the currentPage
>> persistent property.
>>
>> And action listener method
>>
>> public void changePage(IRequestCycle cycle){
>> Integer pageNumber = (Integer) cycle.getServiceParameters()[0];
>> setCurrentPage(pageNumber.intValue());
>> }
>>
>> RD> the extra burden on the template author, who has to specify the
>> RD> parameter on each DirectLink tag.
>>
>> Template author just locates components:
>>
>> <a jwcid="prevLink">previous</a> <a jwcid="nextLink">next</a>
>>
>> There is no parameters specification!
>>
RD> I tend to specify the links directly in the html templates using
RD> jwcid="@DirectLink". I agree that using the jwc file to specify
RD> parameters is more puristic.
RD> However, I have a dynamic set of links, one for each page (like google)
RD> of a data set. I have no choice then but to put them directly in the
RD> html template:
RD> <span jwcid="@Foreach" value="ognl:navigationPage"
RD> source="ognl:navigationPages">
RD> <a jwcid="@DirectLink" listener="ognl:listeners.changePage"
RD> parameters="ognl:navigationPage">
RD> <span jwcid="@Insert" value="ognl:navigationPage + 1"/>
RD> </a>
RD> </span>
I think it can be implemented:
====================
<component id="everyPage" value="ognl:navigationPage">
<binding name="source" expression="navigationPages"/>
<binding name="value" expression="navigationPage"/>
</component>
<component name="pageLink" type="DirectLink">
<binding name="listener" expression="listeners.changePage"/>
<binding name="parameters" expression="navigationPage"/>
<binding name="disabled" expression="current"/>
</component>
<component name="pageIndex" type="Insert">
<binding name="value" expression="navigationPage"/>
</component>
====================
<span jwcid="everyPage">
<a jwcid="pageLink"><span jwcid="pageIndex"/></a>
</span>
====================
RE: Service parameters
Posted by Ruud Diterwich <rd...@cedron.com>.
>
> I don't know what kind of table components you use, but I think it
> should has _persistent_ property 'currentPage'. So when you navigate
> over one table, second keeps it's state. Did you hear something about
> persistent properties? :)
My initial attempt was using persistent properties. However, I was
unable to set a persistent property while rendering. And the value of
the persistent property depends on the result of the query that is
executed in the prepareForRender... (The property must be changed (only)
if the number of result elements is less than a certain value, so it
should be persistent).
>
> RD> So the service parameters introduce a kind of 'global' variable
space,
> RD> which is not in line with 'component-based' development. Not to
> mention
>
> You wrong. Service parameters intended to deliver specific inforamtion
> directly to the component. There is no global space.
You're right, if you make the current page property persistent, you have
the correct behavior.
> Look:
>
> <component name="prevLink" type="DirectLink">
> <binding name="listener" expression="listeners.changePage"/>
> <binding name="parameters" expression="prevPage"/>
> <binding name="disabled" expression="first"/>
> </component>
>
> <component name="nextLink" type="DirectLink">
> <binding name="listener" expression="listeners.changePage"/>
> <binding name="parameters" expression="nextPage"/>
> <binding name="disabled" expression="last"/>
> </component>
>
> It assumes that your table component has isFirst(), isLast(),
> getNext() and getPrevious() methods based on the currentPage
> persistent property.
>
> And action listener method
>
> public void changePage(IRequestCycle cycle){
> Integer pageNumber = (Integer) cycle.getServiceParameters()[0];
> setCurrentPage(pageNumber.intValue());
> }
>
> RD> the extra burden on the template author, who has to specify the
> RD> parameter on each DirectLink tag.
>
> Template author just locates components:
>
> <a jwcid="prevLink">previous</a> <a jwcid="nextLink">next</a>
>
> There is no parameters specification!
>
I tend to specify the links directly in the html templates using
jwcid="@DirectLink". I agree that using the jwc file to specify
parameters is more puristic.
However, I have a dynamic set of links, one for each page (like google)
of a data set. I have no choice then but to put them directly in the
html template:
<span jwcid="@Foreach" value="ognl:navigationPage"
source="ognl:navigationPages">
<a jwcid="@DirectLink" listener="ognl:listeners.changePage"
parameters="ognl:navigationPage">
<span jwcid="@Insert" value="ognl:navigationPage + 1"/>
</a>
</span>
Ruud
Re: Service parameters
Posted by Denis Ponomarev <oz...@romsat.ua>.
RD> True, but my problem with that is that the service parameters are like
RD> url parameters, where we wanted to be abstracted away from. Concrete
I can't realize how you are going to work without service parameters.
RD> problem:
RD> I have 2 table components on one page, each with their own page
RD> numbering and current page. If one table is located at page 5, and a
RD> next page on the second table is selected, the original table falls back
RD> to page 1.
RD>
I don't know what kind of table components you use, but I think it
should has _persistent_ property 'currentPage'. So when you navigate
over one table, second keeps it's state. Did you hear something about
persistent properties? :)
RD> So the service parameters introduce a kind of 'global' variable space,
RD> which is not in line with 'component-based' development. Not to mention
You wrong. Service parameters intended to deliver specific inforamtion
directly to the component. There is no global space.
Look:
<component name="prevLink" type="DirectLink">
<binding name="listener" expression="listeners.changePage"/>
<binding name="parameters" expression="prevPage"/>
<binding name="disabled" expression="first"/>
</component>
<component name="nextLink" type="DirectLink">
<binding name="listener" expression="listeners.changePage"/>
<binding name="parameters" expression="nextPage"/>
<binding name="disabled" expression="last"/>
</component>
It assumes that your table component has isFirst(), isLast(),
getNext() and getPrevious() methods based on the currentPage
persistent property.
And action listener method
public void changePage(IRequestCycle cycle){
Integer pageNumber = (Integer) cycle.getServiceParameters()[0];
setCurrentPage(pageNumber.intValue());
}
RD> the extra burden on the template author, who has to specify the
RD> parameter on each DirectLink tag.
Template author just locates components:
<a jwcid="prevLink">previous</a> <a jwcid="nextLink">next</a>
There is no parameters specification!