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Posted to users@tapestry.apache.org by Paul Stanton <pa...@mapshed.com.au> on 2012/08/04 00:34:02 UTC
type coersion - numbers and booleans
hi all,
originally have an accessor method:
public int getNumericValue()
{
return myInteger; // auto-boxes to int
}
and wanted to use the following if:
<t:if test="numericValue == 3">
however '==' doesn't work, but i know method calls work so i changed to:
public Integer getNumericValue()
{
return myInteger; // no boxing
}
and
<t:if test="numericValue.equals(3)">
this still didn't work, reason being, tapestry 'coerces' "3" into "new
Long(3)" and
new Integer(3) .equals(new Long(3))
returns false.
So i've changed to
public Long getNumericValue()
{
return new Long(myInteger); // a bit ugly
}
and
<t:if test="numericValue.equals(3)">
now works....
SO....................
should tapestry do a better job of
a) coercing 'primative == primative' and the like
b) coercing '3' to 'new Integer(3)' when it is preferable
c) nothing, everything above is as it should be.
discuss.......
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Re: type coersion - numbers and booleans
Posted by Paul Stanton <pa...@mapshed.com.au>.
While I agree with both of you - accessor methods in java classes is
generally better than (minor) logic in templates, there are cases where
some logic in templates is preferable, ie when there are perhaps 10's or
more different numeric cases on the same property. having 10+ near
identical methods doing a simple numeric equals is less maintainable.
in these cases, i miss ognl!
instead of a new component, i've written a public method:
isPropertyEquals(int value)
{
return myproperty == value;
}
p.
On 4/08/2012 1:03 PM, Thiago H de Paula Figueiredo wrote:
> On Fri, 03 Aug 2012 21:07:27 -0300, Howard Lewis Ship
> <hl...@gmail.com> wrote:
>
>> public boolean isNumberThree() { return numericValue == 3; }
>
> In other words, don't put logic in templates, put them in Java
> classes, where it can be easily debugged and tested. ;)
>
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Re: type coersion - numbers and booleans
Posted by Thiago H de Paula Figueiredo <th...@gmail.com>.
On Fri, 03 Aug 2012 21:07:27 -0300, Howard Lewis Ship <hl...@gmail.com>
wrote:
> public boolean isNumberThree() { return numericValue == 3; }
In other words, don't put logic in templates, put them in Java classes,
where it can be easily debugged and tested. ;)
--
Thiago H. de Paula Figueiredo
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Re: type coersion - numbers and booleans
Posted by Howard Lewis Ship <hl...@gmail.com>.
public boolean isNumberThree() { return numericValue == 3; }
Yes, there's some leaky abstractions with method invocations and all
the parameter coercion going on. However, given live class reloading,
creating ad-hoc properties for these comparisons is often more
comparable. Also, instead of "isNumberThree()" it could have semantic
value, as in "isShowExtendedDetails()".
Finally, you can write your own IfEquals component that compares its
two parameters using whatever mechanism works for you.
On Fri, Aug 3, 2012 at 3:34 PM, Paul Stanton <pa...@mapshed.com.au> wrote:
> hi all,
>
> originally have an accessor method:
>
> public int getNumericValue()
> {
> return myInteger; // auto-boxes to int
> }
>
> and wanted to use the following if:
>
> <t:if test="numericValue == 3">
>
> however '==' doesn't work, but i know method calls work so i changed to:
>
> public Integer getNumericValue()
> {
> return myInteger; // no boxing
> }
>
> and
> <t:if test="numericValue.equals(3)">
>
> this still didn't work, reason being, tapestry 'coerces' "3" into "new
> Long(3)" and
>
> new Integer(3) .equals(new Long(3))
>
> returns false.
>
> So i've changed to
>
> public Long getNumericValue()
> {
> return new Long(myInteger); // a bit ugly
> }
>
> and
> <t:if test="numericValue.equals(3)">
>
> now works....
>
> SO....................
>
> should tapestry do a better job of
> a) coercing 'primative == primative' and the like
> b) coercing '3' to 'new Integer(3)' when it is preferable
> c) nothing, everything above is as it should be.
>
>
> discuss.......
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tapestry.apache.org
> For additional commands, e-mail: users-help@tapestry.apache.org
>
--
Howard M. Lewis Ship
Creator of Apache Tapestry
The source for Tapestry training, mentoring and support. Contact me to
learn how I can get you up and productive in Tapestry fast!
(971) 678-5210
http://howardlewisship.com
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