Casebuilder could not determine data type for searched case statement

[michaelhum]

The old code:

new CaseBuilder() .when(foo.id.eq(NumberTemplate.create(Integer.class, "1").then(BooleanTemplate.FALSE) .when(foo.id.eq(NumberTemplate.create(Integer.class, "2").then(BooleanTemplate.TRUE) .otherwise(new NullExpression<>(Boolean.class)

I've tried replacing it with

new CaseBuilder() .when(foo.id.eq(Expressions.asNumber(1).then(false) .when(foo.id.eq(Expressions.asNumber(2)).then(true) .otherwise(Expressions.nullExpression(Boolean.class))

which didn't work. I get the error

org.hibernate.QueryException: Could not determine data type for searched case statement

I then tried using Expressions.constant(), which also didn't work. Finally, I tried Expressions.asBoolean() and Expressions.FALSE, which doesn't compile due to ambiguous method call: valid in Predicate and ComparableExpression.

I should note that explicitly casting Expressions.FALSE to Expression does allow the code to compile (and generate valid SQL), although now there are unchecked warnings.

[ntantri]

Somehow, the syntax you mentioned is not fitting, could you try this:

new CaseBuilder()
.when(foo.id.eq(Expressions.asNumber(1))).then(false)
.when(foo.id.eq(Expressions.asNumber(2))).then(true)
.otherwise(Expressions.nullExpression(Boolean.class))

See the extra ) after Expressions.asNumber(1)

[michaelhum]

My apologies - typo with copying over the code. I still get the same result.

[ntantri]

I guess you can give a try for this solution that was related to Hibernate doing something with lietrals: http://stackoverflow.com/questions/26648491/querydsl-could-not-determine-data-type-for-searched-case-statement#answer-27190771

[Shredder121]

Hibernate doesn't know what type ? is in the query, but needs to know in case expressions.

Using templates like the answer on stackoverflow is an option.
It makes us serialize whatever is in the template as-is.

Other than that, it's a hibernate issue.

[michaelhum]

Hi,

I'll give it a try - although I've tried numerous templates. Is there a specific one? In 3.x I was using NumberTemplate and BooleanTemplate but in 4 I believe it is now different?

I've tried:

Expressions.asBoolean()
Expressions.constant()
Expressions.FALSE

As I did mention though, this syntax:

.when(Expressions.asNumber(1))
.then(Expressions.asBoolean(false))
.when(Expressions.asNumber(2))
.then(Expressions.asBoolean(true))
.otherwise(Expressions.nullExpression(Boolean.class))

results in a compilation error (ambiguous method call with '.then(Expressions.asBoolean(false))' - both overridden in ComparableExpression and Predicate apply. I can make it work by casting the result to Expression, is this expected behaviour?