Compile error when using CriteriaBuilder
I am trying convert this JPA QL to criteria builder. JBoss 6.0.
\"SELECT ba FROM BankAccount ba WHERE ba.balance >= :amt ORDER BY ba.ownerName ASC\"
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The type safety feature in JPA restricts such comparisons with incompatible types, the compiler itself will raise error.
Here,
from.get("balance")returns thePath, but the method can accept parameter of typejava.lang.Number, therefore results in error.You can try the below code.
//-- Metamodel metamodel = em.getMetamodel(); EntityTypepClass = metamodel.entity(BankAccount.class); Predicate predicate = cb.gt(from.get(pClass.getSingularAttribute("balance", Integer.class)), balance); //-- If you are using Metamodel API, then you can retieve directly by specifying ClassName_.field as
cb.gt(from.get(BankAccount_.balance), balance)which is much cleaner & easy to debug.But if you are having many entities, then it may be difficult to write their Metamodel classes manually, if the JPA provider doesn't generate them.
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