DATACMNS-458 - Added PersistentEntities value object.

Introduced simple value object to hide a set of MappingContexts and be able to access PersistentEntities from them.

src/main/java/org/springframework/data/mapping/context/PersistentEntities.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mapping.context;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+import org.springframework.data.mapping.PersistentEntity;
+import org.springframework.data.util.TypeInformation;
+import org.springframework.util.Assert;
+
+/**
+ * Value object to access {@link PersistentEntity} instances managed by {@link MappingContext}s.
+ * 
+ * @author Oliver Gierke
+ * @since 1.8
+ */
+public class PersistentEntities implements Iterable<PersistentEntity<?, ?>> {
+
+	private final Iterable<? extends MappingContext<?, ?>> contexts;
+
+	/**
+	 * Creates a new {@link PersistentEntities} for the given {@link MappingContext}s.
+	 * 
+	 * @param contexts
+	 */
+	public PersistentEntities(Iterable<? extends MappingContext<?, ?>> contexts) {
+
+		Assert.notNull(contexts, "MappingContexts must not be null!");
+		this.contexts = contexts;
+	}
+
+	/**
+	 * Returns the {@link PersistentEntity} for the given type. Will consider all {@link MappingContext}s registered but
+	 * return {@literal null} in case none of the registered ones already have a {@link PersistentEntity} registered for
+	 * the given type.
+	 * 
+	 * @param type can be {@literal null}.
+	 * @return
+	 */
+	public PersistentEntity<?, ?> getPersistentEntity(Class<?> type) {
+
+		for (MappingContext<?, ?> context : contexts) {
+
+			if (context.hasPersistentEntityFor(type)) {
+				return context.getPersistentEntity(type);
+			}
+		}
+
+		return null;
+	}
+
+	/**
+	 * Returns all {@link TypeInformation} exposed by the registered {@link MappingContext}s.
+	 * 
+	 * @return
+	 */
+	public Iterable<TypeInformation<?>> getManagedTypes() {
+
+		Set<TypeInformation<?>> informations = new HashSet<TypeInformation<?>>();
+
+		for (MappingContext<?, ?> context : contexts) {
+			informations.addAll(context.getManagedTypes());
+		}
+
+		return Collections.unmodifiableSet(informations);
+	}
+
+	/* 
+	 * (non-Javadoc)
+	 * @see java.lang.Iterable#iterator()
+	 */
+	@Override
+	public Iterator<PersistentEntity<?, ?>> iterator() {
+
+		List<PersistentEntity<?, ?>> entities = new ArrayList<PersistentEntity<?, ?>>();
+
+		for (MappingContext<?, ?> context : contexts) {
+			entities.addAll(context.getPersistentEntities());
+		}
+
+		return entities.iterator();
+	}
+}

src/test/java/org/springframework/data/mapping/context/PersistentEntitiesUnitTests.java

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2014 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.mapping.context;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.data.util.ClassTypeInformation;
+
+/**
+ * Unit tests for {@link PersistentEntities}.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class PersistentEntitiesUnitTests {
+
+	@Mock SampleMappingContext first;
+	@Mock SampleMappingContext second;
+
+	/**
+	 * @see DATACMNS-458
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void rejectsNullMappingContexts() {
+		new PersistentEntities(null);
+	}
+
+	/**
+	 * @see DATACMNS-458
+	 */
+	@Test
+	public void returnsPersistentEntitiesFromMappingContexts() {
+
+		when(first.hasPersistentEntityFor(Sample.class)).thenReturn(false);
+		when(second.hasPersistentEntityFor(Sample.class)).thenReturn(true);
+
+		new PersistentEntities(Arrays.asList(first, second)).getPersistentEntity(Sample.class);
+
+		verify(first, times(1)).hasPersistentEntityFor(Sample.class);
+		verify(first, times(0)).getPersistentEntity(Sample.class);
+
+		verify(second, times(1)).hasPersistentEntityFor(Sample.class);
+		verify(second, times(1)).getPersistentEntity(Sample.class);
+	}
+
+	/**
+	 * @see DATACMNS-458
+	 */
+	@Test
+	public void indicatesManagedType() {
+
+		SampleMappingContext context = new SampleMappingContext();
+		context.setInitialEntitySet(Collections.singleton(Sample.class));
+		context.initialize();
+
+		PersistentEntities entities = new PersistentEntities(Arrays.asList(context));
+
+		assertThat(entities.getPersistentEntity(Sample.class), is(notNullValue()));
+		assertThat(entities.getPersistentEntity(Object.class), is(nullValue()));
+		assertThat(entities.getManagedTypes(), hasItem(ClassTypeInformation.from(Sample.class)));
+		assertThat(entities, hasItem(entities.getPersistentEntity(Sample.class)));
+	}
+
+	static class Sample {
+
+	}
+}