Merge pull request #17 from olivergierke/SGF-113

SGF-113 - Added support to return single entities from query methods.

src/main/java/org/springframework/data/gemfire/repository/query/StringBasedGemfireRepositoryQuery.java

@@ -19,6 +19,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Iterator;
 
+import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.data.gemfire.GemfireTemplate;
 import org.springframework.data.repository.query.ParametersParameterAccessor;
 import org.springframework.util.Assert;
@@ -34,6 +35,8 @@ import com.gemstone.gemfire.cache.query.internal.ResultsBag;
  */
 public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 
+	private static final String INVALID_EXECUTION = "Paging and modifying queries are not supported!";
+
 	private final QueryString query;
 	private final GemfireQueryMethod method;
 	private final GemfireTemplate template;
@@ -67,6 +70,10 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 		this.query = new QueryString(StringUtils.hasText(query) ? query : method.getAnnotatedQuery());
 		this.method = method;
 		this.template = template;
+
+		if (method.isPageQuery() || method.isModifyingQuery()) {
+			throw new IllegalStateException(INVALID_EXECUTION);
+		}
 	}
 
 	/* 
@@ -83,7 +90,24 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 		while (indexes.hasNext()) {
 			query = query.bindIn(toCollection(accessor.getBindableValue(indexes.next() - 1)));
 		}
-		return toCollection(template.find(query.toString(), parameters));
+
+		Collection<?> result = toCollection(template.find(query.toString(), parameters));
+
+		if (method.isCollectionQuery()) {
+			return result;
+		} else if (method.isQueryForEntity()) {
+
+			if (result.isEmpty()) {
+				return null;
+			} else if (result.size() == 1) {
+				return result.iterator().next();
+			} else {
+				throw new IncorrectResultSizeDataAccessException(1, result.size());
+			}
+
+		} else {
+			throw new IllegalStateException(INVALID_EXECUTION);
+		}
 	}
 
 	/**
@@ -94,15 +118,15 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 	 * @return
 	 */
 	private Collection<?> toCollection(Object source) {
+
 		if (source instanceof ResultsBag) {
-			ResultsBag bag = (ResultsBag)source;
+			ResultsBag bag = (ResultsBag) source;
 			return bag.asList();
 		}
-		
+
 		if (source instanceof Collection) {
 			return (Collection<?>) source;
 		}
-		
 
 		return source.getClass().isArray() ? CollectionUtils.arrayToList(source) : Collections.singleton(source);
 	}

src/test/java/org/springframework/data/gemfire/repository/sample/PersonRepository.java

@@ -42,4 +42,6 @@ public interface PersonRepository extends CrudRepository<Person, Long> {
 	Collection<Person> findByFirstnameAndLastname(String firstname, String lastname);
 
 	Collection<Person> findByFirstnameOrLastname(String firstname, String lastname);
+
+	Person findByLastname(String lastname);
 }

src/test/java/org/springframework/data/gemfire/repository/support/AbstractGemfireRepositoryFactoryIntegrationTests.java

@@ -26,6 +26,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.data.gemfire.GemfireTemplate;
 import org.springframework.data.gemfire.mapping.GemfireMappingContext;
 import org.springframework.data.gemfire.mapping.Regions;
@@ -46,7 +47,7 @@ public abstract class AbstractGemfireRepositoryFactoryIntegrationTests {
 	@Autowired
 	List<Region<?, ?>> regions;
 
-	Person dave, carter, boyd, stefan, leroi, jeff;
+	Person dave, carter, boyd, stefan, leroi, jeff, oliverAugust;
 	PersonRepository repository;
 
 	@Before
@@ -58,6 +59,7 @@ public abstract class AbstractGemfireRepositoryFactoryIntegrationTests {
 		stefan = new Person(4L, "Stefan", "Lessard");
 		leroi = new Person(5L, "Leroi", "Moore");
 		jeff = new Person(6L, "Jeff", "Coffin");
+		oliverAugust = new Person(7L, "Oliver August", "Matthews");
 
 		GemfireMappingContext context = new GemfireMappingContext();
 
@@ -70,6 +72,7 @@ public abstract class AbstractGemfireRepositoryFactoryIntegrationTests {
 		template.put(stefan.id, stefan);
 		template.put(leroi.id, leroi);
 		template.put(jeff.id, jeff);
+		template.put(oliverAugust.id, oliverAugust);
 
 		repository = getRepository(regions);
 	}
@@ -105,7 +108,7 @@ public abstract class AbstractGemfireRepositoryFactoryIntegrationTests {
 
 	@Test
 	public void executesDerivedQueryWithOrCorrectly() {
-		assertResultsFound(repository.findByFirstnameOrLastname("Carter", "Matthews"), carter, dave);
+		assertResultsFound(repository.findByFirstnameOrLastname("Carter", "Matthews"), carter, dave, oliverAugust);
 	}
 
 	/**
@@ -119,6 +122,37 @@ public abstract class AbstractGemfireRepositoryFactoryIntegrationTests {
 		assertResultsFound(repository.findAll());
 	}
 
+	/**
+	 * @see SGF-113
+	 */
+	@Test
+	public void findsPersonByLastname() {
+		assertThat(repository.findByLastname("Beauford"), is(carter));
+	}
+
+	/**
+	 * @see SGF-113
+	 */
+	@Test
+	public void returnsNullForEmptyResultForSingleEntityQuery() {
+		assertThat(repository.findByLastname("Foo"), is(nullValue()));
+	}
+
+	/**
+	 * @see SGF-113
+	 */
+	@Test
+	public void throwsExceptionForMoreThanOneResultForSingleEntityQuery() {
+
+		try {
+			repository.findByLastname("Matthews");
+			fail("Exception expected!");
+		} catch (IncorrectResultSizeDataAccessException e) {
+			assertThat(e.getExpectedSize(), is(1));
+			assertThat(e.getActualSize(), is(2));
+		}
+	}
+
 	private <T> void assertResultsFound(Iterable<T> result, T... expected) {
 
 		assertThat(result, is(notNullValue()));

src/test/java/org/springframework/data/gemfire/repository/support/GemfireRepositoryFactoryIntegrationTests.java

@@ -38,7 +38,7 @@ public class GemfireRepositoryFactoryIntegrationTests extends AbstractGemfireRep
 	}
 
 	@Test(expected = IllegalStateException.class)
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({ "unchecked", "rawtypes" })
 	public void throwsExceptionIfReferencedRegionIsNotConfigured() {
 
 		GemfireRepositoryFactory factory = new GemfireRepositoryFactory((Iterable) Collections.emptySet(), null);