How can I send default value to CriteriaBuilder constructor based selection field?

Question

I am using JPA CriteriaBuilder to create query and uses constructor base selection. But In my case I want some default value to specific parameter (Dummy). But that parameter is not a table column.

Is there any way to achieve this?

CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();
CriteriaQuery<HEntity> cq = cb.createQuery(HEntity.class);
Root<HTable> root = cq.from(HTable.class);

// original selection criteria
// build result set class
cq.select(cb.construct(HDto.class,
                root.<Long>get("id"),
                root.<Date>get("datetime"),
                root.get("device")
               )

Is there any way to achieve like following?

// build result set class
cq.select(cb.construct(HDto.class,
                root.<Long>get("id"),
                root.<Date>get("datetime"),
                root.get("devicename"),
                "default value"
               )

Answer 1

Expression<String> localExp = cb.literal("My String");

Please check below Oracle Doc link http://docs.oracle.com/javaee/6/api/javax/persistence/criteria/CriteriaBuilder.html#literal(T)