Examples for Chapter 14 - RESTful Java with JAX-RS 2.0 - page 338

The getCustomers() method is expanded as compared to previous examples in this topic.
The firstName and lastName query parameters are added. This allows clients to search for
customers in the database with a specific first and last name.

Query query = null null ;

iif ( firstName != null null && lastName != null null )

{

query = em . createQuery (
"select c from Customer c where c.firstName=:first
and c.lastName=:last" );
query . setParameter ( "first" , firstName );
query . setParameter ( "last" , lastName );

}
else else if ( lastName != null null )

{

query = em . createQuery (
"select c from Customer c where c.lastName=:last" );
query . setParameter ( "last" , lastName );

}
else else

{

query = em . createQuery ( "select c from Customer c" );

}

The getCustomers() method builds a JPA query based on the values of firstName and
lastName . If these are both set, it searches in the database for all customers with that first
and last name. If only lastName is set, it searches only for customers with that last name.
Otherwise, it just queries for all customers in the database.

List customerEntities = query . setFirstResult ( start )
. setMaxResults ( size )
. getResultList ();

Next, the code executes the query. You can see that doing paging is a little bit easier with JPA
than the in-memory database we used in Chapter 24 . The setMaxResults() and
query.setFirstResult() methods set the index and size of the dataset you want returned.

for for ( Object obj : customerEntities )

{

CustomerEntity entity = ( CustomerEntity ) obj ;
list . add ( entity2domain ( entity ));

}