DATACMNS-673 - Enhanced RepositoryMetadata to allow returning alternative domain types.

In case a RepositoryMetadata implementation alters the domain type the repository is actually handling, we still have to be able to find the repository based on the type originally declared in the repository.

The newly introduced getAlternativeDomainTypes() is now used by Repositories to register a repository for all types returned by that method, too, so that this reverse lookup still works.

src/test/java/org/springframework/data/repository/core/support/DummyRepositoryInformation.java

@@ -29,7 +29,11 @@ public final class DummyRepositoryInformation implements RepositoryInformation {
 	private final RepositoryMetadata metadata;
 
 	public DummyRepositoryInformation(Class<?> repositoryInterface) {
-		this.metadata = new DefaultRepositoryMetadata(repositoryInterface);
+		this(new DefaultRepositoryMetadata(repositoryInterface));
+	}
+
+	public DummyRepositoryInformation(RepositoryMetadata metadata) {
+		this.metadata = metadata;
 	}
 
 	public Class<? extends Serializable> getIdType() {
@@ -84,4 +88,9 @@ public final class DummyRepositoryInformation implements RepositoryInformation {
 	public boolean isPagingRepository() {
 		return false;
 	}
+
+	@Override
+	public Set<Class<?>> getAlternativeDomainTypes() {
+		return metadata.getAlternativeDomainTypes();
+	}
 }

src/test/java/org/springframework/data/repository/support/RepositoriesUnitTests.java

@@ -23,6 +23,7 @@ import static org.junit.Assert.*;
 import java.io.Serializable;
 import java.util.Collections;
 import java.util.List;
+import java.util.Set;
 
 import org.junit.Before;
 import org.junit.Test;
@@ -45,6 +46,7 @@ import org.springframework.data.repository.core.support.DummyRepositoryFactoryBe
 import org.springframework.data.repository.core.support.DummyRepositoryInformation;
 import org.springframework.data.repository.core.support.RepositoryFactoryInformation;
 import org.springframework.data.repository.query.QueryMethod;
+import org.springframework.util.ClassUtils;
 
 /**
  * Unit tests for {@link Repositories}.
@@ -116,6 +118,27 @@ public class RepositoriesUnitTests {
 		assertThat(new Repositories(context).getPersistentEntity(AdvancedAddress.class), is(notNullValue()));
 	}
 
+	/**
+	 * @see DATACMNS-673
+	 */
+	@Test
+	public void discoversRepositoryForAlternativeDomainType() {
+
+		RepositoryMetadata metadata = new CustomRepositoryMetadata(SampleRepository.class);
+		RepositoryFactoryInformation<?, ?> information = new SampleRepoFactoryInformation<Object, Serializable>(metadata);
+
+		GenericApplicationContext context = new GenericApplicationContext();
+		context.getBeanFactory().registerSingleton("foo", information);
+		context.refresh();
+
+		Repositories repositories = new Repositories(context);
+
+		assertThat(repositories.getRepositoryFor(Sample.class), is(notNullValue()));
+		assertThat(repositories.getRepositoryFor(SampleEntity.class), is(notNullValue()));
+
+		context.close();
+	}
+
 	class Person {}
 
 	class Address {}
@@ -132,7 +155,11 @@ public class RepositoriesUnitTests {
 		private final SampleMappingContext mappingContext;
 
 		public SampleRepoFactoryInformation(Class<?> repositoryInterface) {
-			this.repositoryMetadata = new DefaultRepositoryMetadata(repositoryInterface);
+			this(new DefaultRepositoryMetadata(repositoryInterface));
+		}
+
+		public SampleRepoFactoryInformation(RepositoryMetadata metadata) {
+			this.repositoryMetadata = metadata;
 			this.mappingContext = new SampleMappingContext();
 		}
 
@@ -142,7 +169,7 @@ public class RepositoriesUnitTests {
 		}
 
 		public RepositoryInformation getRepositoryInformation() {
-			return new DummyRepositoryInformation(repositoryMetadata.getRepositoryInterface());
+			return new DummyRepositoryInformation(repositoryMetadata);
 		}
 
 		public PersistentEntity<?, ?> getPersistentEntity() {
@@ -153,4 +180,49 @@ public class RepositoriesUnitTests {
 			return Collections.emptyList();
 		}
 	}
+
+	static class CustomRepositoryMetadata extends DefaultRepositoryMetadata {
+
+		private final Class<?> domainType;
+
+		/**
+		 * @param repositoryInterface
+		 */
+		public CustomRepositoryMetadata(Class<?> repositoryInterface) {
+
+			super(repositoryInterface);
+
+			String domainType = super.getDomainType().getName().concat("Entity");
+
+			try {
+				this.domainType = ClassUtils.forName(domainType, CustomRepositoryMetadata.class.getClassLoader());
+			} catch (Exception e) {
+				throw new RuntimeException(e);
+			}
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.repository.core.support.DefaultRepositoryMetadata#getDomainType()
+		 */
+		@Override
+		public Class<?> getDomainType() {
+			return this.domainType;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.data.repository.core.support.AbstractRepositoryMetadata#getAlternativeDomainTypes()
+		 */
+		@Override
+		public Set<Class<?>> getAlternativeDomainTypes() {
+			return Collections.<Class<?>> singleton(super.getDomainType());
+		}
+	}
+
+	interface Sample {}
+
+	static class SampleEntity implements Sample {}
+
+	interface SampleRepository extends Repository<Sample, Long> {}
 }