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Posted to users@myfaces.apache.org by ma...@accenture.com on 2007/05/25 09:36:46 UTC
Don't understand getValue code of UISelectItems
Hi, i'm looking the method getValue() of UISelectItems:
public Object getValue()
{
if (_value != null) return _value;
ValueBinding vb = getValueBinding("value");
return vb != null ? vb.getValue(getFacesContext()) : null;
}
And I see that if a value property of the SelectItemsTag is setted with
a ValueBinding format, then every time I get getValue() the value is
rebuilded. This could be a problem for example in the case I have a
property value of my managed bead used for value binding that access to
DB to return the result, because in the life cycle of a page, this
getValue() is called more than one time. My question is:
Why the getValueBinding("value") result is not cached? For example:
private Object _vb=null;
private boolean vbCalculated=false;
public Object getValue()
{
if (_value != null) return _value;
if(!vbCalculated) {
ValueBinding moment = getValueBinding("value");
_vb= moment.getValue(getFacesContext());
vbCalculated=true;
}
return _vb;
}
Ciao
Mario
This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
Re: Don't understand getValue code of UISelectItems
Posted by David Delbecq <de...@oma.be>.
I don't think so, the values in your db can change whenever you want,
that's why the value is evaluated at each request of 'getValue'. But
your proposed change to UISelectItem would break it :)
En l'instant précis du 25/05/07 10:50, mario.buonopane@accenture.com
s'exprimait en ces termes:
> Sorry, change should with could...
>
> Could be a problem if the list of values changed between encodeBegin and encodeEnd phase?
>
> Mario
>
> -----Original Message-----
> From: mario.buonopane@accenture.com [mailto:mario.buonopane@accenture.com]
> Sent: 25 maggio 2007 10.35
> To: users@myfaces.apache.org
> Subject: RE: Don't understand getValue code of UISelectItems
>
> Should be a problem if the list of values changed between encodeBegin and encodeEnd phase?
>
> Mario
>
> -----Original Message-----
> From: David Delbecq [mailto:delbd+jakarta@oma.be]
> Sent: 25 maggio 2007 10.24
> To: MyFaces Discussion
> Subject: Re: Don't understand getValue code of UISelectItems
>
> Hi Mario,
>
> En l'instant précis du 25/05/07 09:36, mario.buonopane@accenture.com
> s'exprimait en ces termes:
>
>> Hi, i'm looking the method getValue() of UISelectItems:
>>
>>
>>
>> public Object getValue()
>>
>> {
>>
>> if (_value != null) return _value;
>>
>> ValueBinding vb = getValueBinding("value");
>>
>> return vb != null ? vb.getValue(getFacesContext()) : null;
>>
>> }
>>
>>
>>
>> And I see that if a value property of the SelectItemsTag is setted
>> with a ValueBinding format, then every time I get getValue() the value
>> is rebuilded.
>>
>>
> Correct
>
>> This could be a problem for example in the case I have a property
>> value of my managed bead used for value binding that access to DB to
>> return the result, because in the life cycle of a page, this
>> getValue() is called more than one time. My question is:
>>
>> Why the getValueBinding("value") result is not cached? For example:
>>
>>
>>
>>
>>
>> private Object _vb=null;
>>
>> private boolean vbCalculated=false;
>>
>>
>>
>> public Object getValue()
>>
>> {
>>
>> if (_value != null) return _value;
>>
>> if(!vbCalculated) {
>>
>> ValueBinding moment = getValueBinding("value");
>>
>> _vb= moment.getValue(getFacesContext());
>>
>> vbCalculated=true;
>>
>> }
>>
>> return _vb;
>>
>> }
>>
>>
>>
>>
>>
>> Ciao
>>
>> Mario
>>
>>
> Let's assume it does it and does not break JSF specification (am sure it
> would). Because there is no method specified in JSF api, which myface
> must respect, to 'invalidate calculated valuebinding', how can your
> application tell all select items of the form that the list of values
> changed between the validation and the render phase?
> You demonstrated how easy it is to cache a value result, then just do it
> in your backing bean and you performance problem is solved. There is no
> reason to do that in the jsf itself. JSF does what is told to it, use a
> "dynamic" value :)
>
>> This message is for the designated recipient only and may contain
>> privileged, proprietary, or otherwise private information. If you have
>> received it in error, please notify the sender immediately and delete
>> the original. Any other use of the email by you is prohibited.
>>
>>
> Useless disclaimer when posting to mailing list ^-^
>
> Regards,
> David
>
>
>
> This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
>
>
> This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
>
RE: Don't understand getValue code of UISelectItems
Posted by ma...@accenture.com.
Sorry, change should with could...
Could be a problem if the list of values changed between encodeBegin and encodeEnd phase?
Mario
-----Original Message-----
From: mario.buonopane@accenture.com [mailto:mario.buonopane@accenture.com]
Sent: 25 maggio 2007 10.35
To: users@myfaces.apache.org
Subject: RE: Don't understand getValue code of UISelectItems
Should be a problem if the list of values changed between encodeBegin and encodeEnd phase?
Mario
-----Original Message-----
From: David Delbecq [mailto:delbd+jakarta@oma.be]
Sent: 25 maggio 2007 10.24
To: MyFaces Discussion
Subject: Re: Don't understand getValue code of UISelectItems
Hi Mario,
En l'instant précis du 25/05/07 09:36, mario.buonopane@accenture.com
s'exprimait en ces termes:
>
> Hi, i'm looking the method getValue() of UISelectItems:
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> ValueBinding vb = getValueBinding("value");
>
> return vb != null ? vb.getValue(getFacesContext()) : null;
>
> }
>
>
>
> And I see that if a value property of the SelectItemsTag is setted
> with a ValueBinding format, then every time I get getValue() the value
> is rebuilded.
>
Correct
>
> This could be a problem for example in the case I have a property
> value of my managed bead used for value binding that access to DB to
> return the result, because in the life cycle of a page, this
> getValue() is called more than one time. My question is:
>
> Why the getValueBinding("value") result is not cached? For example:
>
>
>
>
>
> private Object _vb=null;
>
> private boolean vbCalculated=false;
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> if(!vbCalculated) {
>
> ValueBinding moment = getValueBinding("value");
>
> _vb= moment.getValue(getFacesContext());
>
> vbCalculated=true;
>
> }
>
> return _vb;
>
> }
>
>
>
>
>
> Ciao
>
> Mario
>
Let's assume it does it and does not break JSF specification (am sure it
would). Because there is no method specified in JSF api, which myface
must respect, to 'invalidate calculated valuebinding', how can your
application tell all select items of the form that the list of values
changed between the validation and the render phase?
You demonstrated how easy it is to cache a value result, then just do it
in your backing bean and you performance problem is solved. There is no
reason to do that in the jsf itself. JSF does what is told to it, use a
"dynamic" value :)
>
> This message is for the designated recipient only and may contain
> privileged, proprietary, or otherwise private information. If you have
> received it in error, please notify the sender immediately and delete
> the original. Any other use of the email by you is prohibited.
>
Useless disclaimer when posting to mailing list ^-^
Regards,
David
This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
RE: Don't understand getValue code of UISelectItems
Posted by ma...@accenture.com.
Should be a problem if the list of values changed between encodeBegin and encodeEnd phase?
Mario
-----Original Message-----
From: David Delbecq [mailto:delbd+jakarta@oma.be]
Sent: 25 maggio 2007 10.24
To: MyFaces Discussion
Subject: Re: Don't understand getValue code of UISelectItems
Hi Mario,
En l'instant précis du 25/05/07 09:36, mario.buonopane@accenture.com
s'exprimait en ces termes:
>
> Hi, i'm looking the method getValue() of UISelectItems:
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> ValueBinding vb = getValueBinding("value");
>
> return vb != null ? vb.getValue(getFacesContext()) : null;
>
> }
>
>
>
> And I see that if a value property of the SelectItemsTag is setted
> with a ValueBinding format, then every time I get getValue() the value
> is rebuilded.
>
Correct
>
> This could be a problem for example in the case I have a property
> value of my managed bead used for value binding that access to DB to
> return the result, because in the life cycle of a page, this
> getValue() is called more than one time. My question is:
>
> Why the getValueBinding("value") result is not cached? For example:
>
>
>
>
>
> private Object _vb=null;
>
> private boolean vbCalculated=false;
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> if(!vbCalculated) {
>
> ValueBinding moment = getValueBinding("value");
>
> _vb= moment.getValue(getFacesContext());
>
> vbCalculated=true;
>
> }
>
> return _vb;
>
> }
>
>
>
>
>
> Ciao
>
> Mario
>
Let's assume it does it and does not break JSF specification (am sure it
would). Because there is no method specified in JSF api, which myface
must respect, to 'invalidate calculated valuebinding', how can your
application tell all select items of the form that the list of values
changed between the validation and the render phase?
You demonstrated how easy it is to cache a value result, then just do it
in your backing bean and you performance problem is solved. There is no
reason to do that in the jsf itself. JSF does what is told to it, use a
"dynamic" value :)
>
> This message is for the designated recipient only and may contain
> privileged, proprietary, or otherwise private information. If you have
> received it in error, please notify the sender immediately and delete
> the original. Any other use of the email by you is prohibited.
>
Useless disclaimer when posting to mailing list ^-^
Regards,
David
This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited.
Re: Don't understand getValue code of UISelectItems
Posted by David Delbecq <de...@oma.be>.
Hi Mario,
En l'instant précis du 25/05/07 09:36, mario.buonopane@accenture.com
s'exprimait en ces termes:
>
> Hi, i’m looking the method getValue() of UISelectItems:
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> ValueBinding vb = getValueBinding("value");
>
> return vb != null ? vb.getValue(getFacesContext()) : null;
>
> }
>
>
>
> And I see that if a value property of the SelectItemsTag is setted
> with a ValueBinding format, then every time I get getValue() the value
> is rebuilded.
>
Correct
>
> This could be a problem for example in the case I have a property
> value of my managed bead used for value binding that access to DB to
> return the result, because in the life cycle of a page, this
> getValue() is called more than one time. My question is:
>
> Why the getValueBinding("value") result is not cached? For example:
>
>
>
>
>
> private Object _vb=null;
>
> private boolean vbCalculated=false;
>
>
>
> public Object getValue()
>
> {
>
> if (_value != null) return _value;
>
> if(!vbCalculated) {
>
> ValueBinding moment = getValueBinding("value");
>
> _vb= moment.getValue(getFacesContext());
>
> vbCalculated=true;
>
> }
>
> return _vb;
>
> }
>
>
>
>
>
> Ciao
>
> Mario
>
Let's assume it does it and does not break JSF specification (am sure it
would). Because there is no method specified in JSF api, which myface
must respect, to 'invalidate calculated valuebinding', how can your
application tell all select items of the form that the list of values
changed between the validation and the render phase?
You demonstrated how easy it is to cache a value result, then just do it
in your backing bean and you performance problem is solved. There is no
reason to do that in the jsf itself. JSF does what is told to it, use a
"dynamic" value :)
>
> This message is for the designated recipient only and may contain
> privileged, proprietary, or otherwise private information. If you have
> received it in error, please notify the sender immediately and delete
> the original. Any other use of the email by you is prohibited.
>
Useless disclaimer when posting to mailing list ^-^
Regards,
David