On Nov 18, 2013, at 12:21 PM, Konstantin Kolinko wrote:
> 2013/11/18 Nick Williams <[email protected]>:
>>
>
>>>
>>> Regarding the list() example,
>>> "map(u -> [u.username, u.firstName, u.lastName])" creates a
>>> List<Object> with 3 elements and you are asking for "lastName"
>>> property on that list.
>>
>> No, this is not correct. The lambda expression "u -> [u.username,
>> u.firstName, u.lastName]" RETURNS a List<Object>. But "u" is a User. I am
>> creating a List<Object> where the first element is the user's username, the
>> second element is the user's first name, and the third element is the user's
>> last name. That is completely valid. It is also essentially identical to
>> Section 2.3.6.4's example "p->[p.name, p.unitPrice]."
>>
>>>
>>> It is no wonder that it results in NumberFormatException. (Whether
>>> there should be other handling for wrong property name here, I do not
>>> know. One should look into what resolvers are being used here).
>>
>> It should not result in any exception. It should work, because the syntax is
>> valid, as explained above. :-)
>>
>
> You apply map() which replaces each user with a list [u.username,
> u.firstName, u.lastName].
>
> Then you try to apply sorted() to that list. That sorted() fails as it
> cannot evaluate "u1.lastName.compareTo(u2.lastName)".
>
> As I said - provide a simple example.
Okay, I see where the confusion is. Indeed, when I moved "map" to after
"sorted" the list-literal started working. So it's only the map-literal that is
failing. My apologies; I'll revise the bug.
>
>>>
>>>>>> Section 2.3.6.4 of the specification uses the following example, where a
>>>>>> LIST literal is used as the right-hand side of the mapping lambda
>>>>>> expression:
>>>>>>
>>>>>> products.stream().filter(p->p.unitPrice >= 10).
>>>>>> .map(p->[p.name, p.unitPrice])
>>>>>> .toList()
>>>>>>
>>>>>> I tried to use this exact syntax, as shown in the spec, with my example:
>>>>>>
>>>>>> ${users.stream()
>>>>>> .filter(u -> fn:contains(u.username, '1'))
>>>>>> .map(u -> [u.username, u.firstName, u.lastName])
>>>>>> .sorted((u1, u2) -> u1.lastName.compareTo(u2.lastName) == 0
>>>>>> ? u1.firstName.compareTo(u2.firstName) :
>>>>>> u1.lastName.compareTo(u2.lastName))
>>>>>> .toList()}
>>>>>>
>>>>>> And now I get this lovely error:
>>>>>>
>>>>>> javax.el.ELException: java.lang.NumberFormatException: For input string:
>>>>>> "lastName"
>>>>>> javax.el.BeanELResolver.invoke(BeanELResolver.java:185)
>>>>>>
>>>>>> org.apache.jasper.el.JasperELResolver.invoke(JasperELResolver.java:147)
>>>>>> org.apache.el.parser.AstValue.getValue(AstValue.java:158)
>>>>>> ...
>>>>>>
>>>
>>> Best regards,
>>> Konstantin Kolinko
>>
>> Thanks,
>>
>> Nick
Nick
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