How to keep type safety for an aliased column in Jooq?

user_59241 0
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Let's say I want to select the max value of a specific field:

getContext().select( ..., //several fields
                    DSL.max(MY_TABLE.SCORE).as("max_score"))
            .from(MY_TABLE)
            .where(...)
            .groupBy(...);

I fetch the results, and now I want to get the values of a specific record, so I do:

Integer maxScore = (Integer) record.get("max_score");

This is working just fine, but I have 2 issues with this approach:

  1. Type safety is lost - I must cast the value to Integer.
  2. Although this field will never be null, Jooq is not aware of this. If I define maxScore as int instead of Integer, I get a warning on this line: Unboxing of 'record.get("max_score")' may produce 'NullPointerException'. For table's "not-null" fields, I don't get this warning.

Is there a way to overcome these issues?

jooq alias
1 Answers

Type safety is lost - I must cast the value to Integer.

You can just assign it to a local variable:

Field<Integer> maxScore = max(MY_TABLE.SCORE).as("max_score");

Use it like this:

.select(..., maxScore)
.from(...)

And then:

record.get(maxScore);

If I define maxScore as int instead of Integer, I get a warning [...]

The warning is likely to go away with the above approach. While Record.get(String) returns @Nullable Object, Record.get(Field<T>) just returns T (inheriting T's nullability, which is likely to be unspecified).

user_5217990
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