[BUG] problem accessing java math class constants

[jh-midi]

declare namespace math="java:java.lang.Math";

math:sqrt(2) (: work well :)

(: but access of class constant don't work as expected :)

declare namespace math="java:java.lang.Math";
math:PI() (: don't work :)

SAXON example

<a xmlns:double="java:java.lang.Double"> 
    { double:MAX_VALUE() } don't work
</a>

existdb 6.2.0

[adamretter]

This is disabled in eXist-db by default. You would need to change enable-java-binding="no" to enable-java-binding="yes" in your eXist-db's conf.xml file.

[jh-midi]

yes, this is enabled : and function work

declare namespace double = "java:java.lang.Double";

double:doubleValue(xs:integer(50)) 

=> 5.0e1 => "ok"

but

declare namespace double = "java:java.lang.Double";

double:MAX_VALUE()

=> Cannot compile xquery: exerr:ERROR no method matches MAX_VALUE with 0 arguments [at line 5, column 1, source: String/-3378769710902313501]

the same error occur with

Math:PI()

I am on jdk-17.0.8.7-hotspot Eclipse Adoptium

[jh-midi]

Thank you very much !
NOTICE:
double:doubleValue(xs:integer(50)) is not a very good example because normaly it should not work
because xs:integer is not xs:double ...

declare namespace double = "java:java.lang.Double";
double:doubleValue(xs:double(50)) ,
double:intValue(xs:double(100.55)) ,
double:MAX_VALUE()

expected result = (50, 100, 1.7976931348623157E308)

[adamretter]

double:MAX_VALUE()

MAX_VALUE is not a function call in Java it is a constant, so try changing your XQuery from double:MAX_VALUE() to $double:MAX_VALUE.

Math:PI()

Likewise, this is not a function in java.lang.Math, it is a constant. Try:

declare namespace math = "java:java.lang.Math";
$math:PI

[jh-midi]

Have you tried that on eXide ?
Here this don't work .
Sorry,

with Saxon and Basex my script work well

[jh-midi]

[jh-midi]

for example look at
https://www.saxonica.com/documentation12/index.html#!extensibility/extension-functions-J/reflexive-functions/staticmethods

[adamretter]

Have you tried that on eXide

No. Apologies, I tried it elsewhere.

Here this don't work .

I can now confirm that eXist-db does not support accessing anything apart from static functions, or functions via a previously invoked constructor.

with Saxon and Basex my script work well

You or someone else would need to send a PR to add a feature to eXist-db to support Java class members (e.g. constants) and/or public non-static members. The relevant class in eXist-db is currently org.exist.xquery.JavaCall.