Thanks for your help. I'm still trying to work through it.
I think one of the sticking points for me is creating a table with
arbitrary numbers of rows and keeping the type safety.
If I have several distinct variables for my rows, then it is easy to keep
type safety with the DSL.values(Row3<T1,T2,T3> rows...) method. The
compiler can enforce the generic types:
Row3<String, Integer, Integer> row1 = DSL.row("x", 1, 2);
Row3<String, Integer, Integer> row2 = DSL.row("y", 3, 4);
Row3<String, Integer, Integer> row3 = DSL.row("z", 5, 6);
Table<Record3<String, Integer, Integer>> values = DSL.values(row1, row2,
row3);
But If I first put those rows into a List<Row3>, the compiler cannot do the
type checking because it is necessary to first convert the List into an
array, and it isn't possible to have generic parameters in array
declarations. Java looses all notion of generic types when the array is
declared. (Using a List<Row3> or array Row3[] is what I need because I'm
adding items in a loop.)
List<Row3<String, Integer, Integer>> rowList = new ArrayList<>();
rowList.add(row1);
rowList.add(row2);
rowList.add(row3);
Row3[] rows = rowList.toArray(new Row3[rowList.size()]); // generic
parameters are lost here
Table<Record> values = DSL.values(rows);
The compiler has no way of knowing the generic parameters of each Record
anymore. In fact, it will compile and execute non-sense like this:
Table<Record4<Double, String, Integer,String>> userInput = DSL.values(
rows);
If the DSL class had a method
DSL.values(Collection<Row3<T1,T2,T3>> rows)
then that would work better at preserving type safety than this:
DSL.values(Row3<T1,T2,T3> rows...)
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