#15 - Added example for top/first keywords in repository methods.

jpa/example/src/main/java/example/springdata/jpa/simple/SimpleUserRepository.java

@@ -19,6 +19,7 @@ import java.util.List;
 
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Slice;
+import org.springframework.data.domain.Sort;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.data.repository.query.Param;
@@ -93,4 +94,28 @@ public interface SimpleUserRepository extends CrudRepository<User, Long> {
 	 * @return
 	 */
 	Slice<User> findByLastnameOrderByUsernameAsc(String lastname, Pageable page);
+
+	/**
+	 * Return the first 2 users ordered by their lastname asc.
+	 * 
+	 * <pre>
+	 * Example for findFirstK / findTopK functionality.
+	 * </pre>
+	 * 
+	 * @return
+	 */
+	List<User> findFirst2ByOrderByLastnameAsc();
+
+	/**
+	 * Return the first 2 users ordered by the given {@code sort} definition.
+	 * 
+	 * <pre>
+	 * This variant is very flexible because one can ask for the first K results when a ASC ordering
+	 * is used as well as for the last K results when a DESC ordering is used.
+	 * </pre>
+	 * 
+	 * @param sort
+	 * @return
+	 */
+	List<User> findTop2By(Sort sort);
 }

jpa/example/src/test/java/example/springdata/jpa/simple/SimpleUserRepositoryTests.java

@@ -18,6 +18,7 @@ package example.springdata.jpa.simple;
 import static org.hamcrest.CoreMatchers.*;
 import static org.hamcrest.collection.IsIterableContainingInOrder.*;
 import static org.junit.Assert.*;
+import static org.springframework.data.domain.Sort.Direction.*;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -29,6 +30,7 @@ import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Slice;
+import org.springframework.data.domain.Sort;
 import org.springframework.test.context.ContextConfiguration;
 import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
 import org.springframework.transaction.annotation.Transactional;
@@ -136,4 +138,51 @@ public class SimpleUserRepositoryTests {
 
 		assertThat(users, contains(source.subList(5, 10).toArray()));
 	}
+
+	@Test
+	public void findFirst2ByOrderByLastnameAsc() {
+
+		User user0 = new User();
+		user0.setLastname("lastname-0");
+
+		User user1 = new User();
+		user1.setLastname("lastname-1");
+
+		User user2 = new User();
+		user2.setLastname("lastname-2");
+
+		// we deliberatly save the items in reverse
+		repository.save(Arrays.asList(user2, user1, user0));
+
+		List<User> result = repository.findFirst2ByOrderByLastnameAsc();
+
+		assertThat(result.size(), is(2));
+		assertThat(result, hasItems(user0, user1));
+	}
+
+	@Test
+	public void findTop2ByWithSort() {
+
+		User user0 = new User();
+		user0.setLastname("lastname-0");
+
+		User user1 = new User();
+		user1.setLastname("lastname-1");
+
+		User user2 = new User();
+		user2.setLastname("lastname-2");
+
+		// we deliberately save the items in reverse
+		repository.save(Arrays.asList(user2, user1, user0));
+
+		List<User> resultAsc = repository.findTop2By(new Sort(ASC, "lastname"));
+
+		assertThat(resultAsc.size(), is(2));
+		assertThat(resultAsc, hasItems(user0, user1));
+
+		List<User> resultDesc = repository.findTop2By(new Sort(DESC, "lastname"));
+
+		assertThat(resultDesc.size(), is(2));
+		assertThat(resultDesc, hasItems(user1, user2));
+	}
 }