DATAKV-169 - Add support for IN keyword in derived queries.

We now support `In` keyword in derived finder methods (eg. `findByFirstnameIn(Collection<String> firstnames)`) when using SpEL based queries.

Original pull request: #23.

src/test/java/org/springframework/data/keyvalue/repository/query/SpelQueryCreatorUnitTests.java

@@ -20,6 +20,7 @@ import static org.junit.Assert.*;
 import static org.mockito.Mockito.*;
 
 import java.lang.reflect.Method;
+import java.util.ArrayList;
 import java.util.Date;
 
 import org.joda.time.format.DateTimeFormatter;
@@ -380,6 +381,66 @@ public class SpelQueryCreatorUnitTests {
 		assertThat(evaluate("findByLastnameMatches", "^s.*w$").against(ROBB), is(false));
 	}
 
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void inReturnsMatchCorrectly() throws Exception {
+
+		ArrayList<String> list = new ArrayList<String>();
+		list.add(ROBB.firstname);
+
+		assertThat(evaluate("findByFirstnameIn", list).against(ROBB), is(true));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void inNotMatchingReturnsCorrectly() throws Exception {
+
+		ArrayList<String> list = new ArrayList<String>();
+		list.add(ROBB.firstname);
+
+		assertThat(evaluate("findByFirstnameIn", list).against(JON), is(false));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void inWithNullCompareValuesCorrectly() throws Exception {
+
+		ArrayList<String> list = new ArrayList<String>();
+		list.add(null);
+
+		assertThat(evaluate("findByFirstnameIn", list).against(JON), is(false));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void inWithNullSourceValuesMatchesCorrectly() throws Exception {
+
+		ArrayList<String> list = new ArrayList<String>();
+		list.add(ROBB.firstname);
+
+		assertThat(evaluate("findByFirstnameIn", list).against(new Person(null, 10)), is(false));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void inMatchesNullValuesCorrectly() throws Exception {
+
+		ArrayList<String> list = new ArrayList<String>();
+		list.add(null);
+
+		assertThat(evaluate("findByFirstnameIn", list).against(new Person(null, 10)), is(true));
+	}
+
 	private Evaluation evaluate(String methodName, Object... args) throws Exception {
 		return new Evaluation((SpelExpression) createQueryForMethodWithArgs(methodName, args).getCritieria());
 	}
@@ -464,6 +525,9 @@ public class SpelQueryCreatorUnitTests {
 		// Type.REGEX
 		Person findByLastnameMatches(String lastname);
 
+		// Type.IN
+		Person findByFirstnameIn(ArrayList<String> in);
+
 	}
 
 	static class Evaluation {

src/test/java/org/springframework/data/map/AbstractRepositoryUnitTests.java

@@ -39,7 +39,7 @@ import org.springframework.data.repository.CrudRepository;
 
 /**
  * Base class for test cases for repository implementations.
- * 
+ *
  * @author Christoph Strobl
  * @author Oliver Gierke
  * @author Thomas Darimont
@@ -200,13 +200,60 @@ public abstract class AbstractRepositoryUnitTests<T extends AbstractRepositoryUn
 		assertThat(result.get(0).getFirstname(), is(CERSEI.getFirstname()));
 	}
 
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void findsByValueInCollectionCorrectly() {
+
+		repository.save(LENNISTERS);
+
+		List<Person> result = repository.findByFirstnameIn(Arrays.asList(CERSEI.getFirstname(), JAIME.getFirstname()));
+
+		assertThat(result, hasSize(2));
+		assertThat(result, is(containsInAnyOrder(CERSEI, JAIME)));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void findsByValueInCollectionCorrectlyWhenTargetPathContainsNullValue() {
+
+		repository.save(LENNISTERS);
+		repository.save(new Person(null, 10));
+
+		List<Person> result = repository.findByFirstnameIn(Arrays.asList(CERSEI.getFirstname(), JAIME.getFirstname()));
+
+		assertThat(result, hasSize(2));
+		assertThat(result, is(containsInAnyOrder(CERSEI, JAIME)));
+	}
+
+	/**
+	 * @see DATAKV-169
+	 */
+	@Test
+	public void findsByValueInCollectionCorrectlyWhenTargetPathAndCollectionContainNullValue() {
+
+		repository.save(LENNISTERS);
+
+		Person personWithNullAsFirstname = new Person(null, 10);
+		repository.save(personWithNullAsFirstname);
+
+		List<Person> result = repository
+				.findByFirstnameIn(Arrays.asList(CERSEI.getFirstname(), JAIME.getFirstname(), null));
+
+		assertThat(result, hasSize(3));
+		assertThat(result, is(containsInAnyOrder(CERSEI, JAIME, personWithNullAsFirstname)));
+	}
+
 	protected KeyValueRepositoryFactory createKeyValueRepositoryFactory(KeyValueOperations operations) {
 		return new KeyValueRepositoryFactory(operations);
 	}
 
 	protected abstract T getRepository(KeyValueRepositoryFactory factory);
 
-	public static interface PersonRepository extends CrudRepository<Person, String>, KeyValueRepository<Person, String> {
+	public interface PersonRepository extends CrudRepository<Person, String>, KeyValueRepository<Person, String> {
 
 		List<Person> findByAge(int age);
 
@@ -225,6 +272,8 @@ public abstract class AbstractRepositoryUnitTests<T extends AbstractRepositoryUn
 		List<PersonSummary> findByAgeGreaterThan(int age, Sort sort);
 
 		<T> List<T> findByAgeGreaterThan(int age, Sort sort, Class<T> projectionType);
+
+		List<Person> findByFirstnameIn(List<String> firstname);
 	}
 
 	interface PersonSummary {