DATAREDIS-425 - Add CompositeIndexResolver.

Add a composite IndexResolver implementation that iterates over a given collection of delegate
IndexResolver instances and collects IndexedData from those.

Author: christophstrobl

src/main/java/org/springframework/data/redis/core/convert/CompositeIndexResolver.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2016 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.redis.core.convert;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.springframework.data.util.TypeInformation;
+import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
+
+/**
+ * Composite {@link IndexResolver} implementation that iterates over a given collection of delegate
+ * {@link IndexResolver} instances. <br />
+ * <br />
+ * <strong>NOTE</strong> {@link IndexedData} created by an {@link IndexResolver} can be overwritten by subsequent
+ * {@link IndexResolver}.
+ * 
+ * @author Christoph Strobl
+ * @since 1.7
+ */
+public class CompositeIndexResolver implements IndexResolver {
+
+	private final List<IndexResolver> resolvers;
+
+	/**
+	 * Create new {@link CompositeIndexResolver}.
+	 * 
+	 * @param resolvers must not be {@literal null}.
+	 */
+	public CompositeIndexResolver(Collection<IndexResolver> resolvers) {
+
+		Assert.notNull(resolvers, "Resolvers must not be null!");
+		if (CollectionUtils.contains(resolvers.iterator(), null)) {
+			throw new IllegalArgumentException("Resolvers must no contain null values");
+		}
+		this.resolvers = new ArrayList<IndexResolver>(resolvers);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.core.convert.IndexResolver#resolveIndexesFor(org.springframework.data.util.TypeInformation, java.lang.Object)
+	 */
+	@Override
+	public Set<IndexedData> resolveIndexesFor(TypeInformation<?> typeInformation, Object value) {
+
+		if (resolvers.isEmpty()) {
+			return Collections.emptySet();
+		}
+
+		Set<IndexedData> data = new LinkedHashSet<IndexedData>();
+		for (IndexResolver resolver : resolvers) {
+			data.addAll(resolver.resolveIndexesFor(typeInformation, value));
+		}
+		return data;
+	}
+
+}

src/test/java/org/springframework/data/redis/core/convert/CompositeIndexResolverUnitTests.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2016 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.redis.core.convert;
+
+import static org.hamcrest.core.IsEqual.*;
+import static org.junit.Assert.*;
+import static org.mockito.Matchers.*;
+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.TypeInformation;
+
+/**
+ * @author Christoph Strobl
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class CompositeIndexResolverUnitTests {
+
+	@Mock IndexResolver resolver1;
+	@Mock IndexResolver resolver2;
+	@Mock TypeInformation<?> typeInfoMock;
+
+	/**
+	 * @see DATAREDIS-425
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldRejectNull() {
+		new CompositeIndexResolver(null);
+	}
+
+	/**
+	 * @see DATAREDIS-425
+	 */
+	@Test(expected = IllegalArgumentException.class)
+	public void shouldRejectCollectionWithNullValues() {
+		new CompositeIndexResolver(Arrays.asList(resolver1, null, resolver2));
+	}
+
+	/**
+	 * @see DATAREDIS-425
+	 */
+	@Test
+	public void shouldCollectionIndexesFromResolvers() {
+
+		when(resolver1.resolveIndexesFor(any(TypeInformation.class), anyObject())).thenReturn(
+				Collections.<IndexedData> singleton(new SimpleIndexedPropertyValue("spring", "data", "redis")));
+		when(resolver2.resolveIndexesFor(any(TypeInformation.class), anyObject())).thenReturn(
+				Collections.<IndexedData> singleton(new SimpleIndexedPropertyValue("redis", "data", "spring")));
+
+		CompositeIndexResolver resolver = new CompositeIndexResolver(Arrays.asList(resolver1, resolver2));
+
+		assertThat(resolver.resolveIndexesFor(typeInfoMock, "o.O").size(), equalTo(2));
+	}
+}