DATAGEODE-244 - Add RegionResolver implementation resolving a single, configured Region object.

spring-data-geode/src/main/java/org/springframework/data/gemfire/support/SingleRegionRegionResolver.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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.gemfire.support;
+
+import org.apache.geode.cache.Region;
+
+import org.springframework.data.gemfire.RegionResolver;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * {@link RegionResolver} implementation resolving a single, configured {@link Region} object.
+ *
+ * @author John Blum
+ * @see org.apache.geode.cache.Region
+ * @see org.springframework.data.gemfire.RegionResolver
+ * @since 2.3.0
+ */
+@SuppressWarnings("rawtypes")
+public class SingleRegionRegionResolver implements RegionResolver {
+
+	private final Region region;
+
+	/**
+	 * Constructs a new instance of {@link SingleRegionRegionResolver} with the given {@link Region}.
+	 *
+	 * @param region {@link Region} returned in the resolution process; must not be {@literal null}.
+	 * @throws IllegalArgumentException if {@link Region} is {@literal null}.
+	 * @see org.apache.geode.cache.Region
+	 */
+	public SingleRegionRegionResolver(@NonNull Region region) {
+
+		Assert.notNull(region, "Region must not be null");
+
+		this.region = region;
+	}
+
+	/**
+	 * Returns a reference to the configured {@link Region}.
+	 *
+	 * @param <K> {@link Class type} of the {@link Region} key.
+	 * @param <V> {@link Class type} of the {@link Region} value.
+	 * @return a reference to the configured {@link Region}.
+	 * @see org.apache.geode.cache.Region
+	 */
+	@SuppressWarnings("unchecked")
+	protected @NonNull <K, V> Region<K, V> getRegion() {
+		return this.region;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	@Override
+	public @Nullable <K, V> Region<K, V> resolve(@Nullable String regionName) {
+
+		Region<K, V> region = getRegion();
+
+		return region.getName().equals(regionName) ? region : null;
+	}
+}

spring-data-geode/src/test/java/org/springframework/data/gemfire/support/SingleRegionRegionResolverUnitTests.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2020 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
+ *
+ *      https://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.gemfire.support;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import org.apache.geode.cache.Region;
+
+/**
+ * Unit Tests for {@link SingleRegionRegionResolver}.
+ *
+ * @author John Blum
+ * @see org.junit.Test
+ * @see org.mockito.Mockito
+ * @see org.mockito.junit.MockitoJUnitRunner
+ * @see org.apache.geode.cache.Region
+ * @see org.springframework.data.gemfire.support.SingleRegionRegionResolver
+ * @since 2.3.0
+ */
+@RunWith(MockitoJUnitRunner.class)
+@SuppressWarnings("rawtypes")
+public class SingleRegionRegionResolverUnitTests {
+
+	@Mock
+	private Region mockRegion;
+
+	@Test
+	public void constructSingleRegionRegionResolverWithRegion() {
+
+		SingleRegionRegionResolver regionResolver = new SingleRegionRegionResolver(this.mockRegion);
+
+		assertThat(regionResolver).isNotNull();
+		assertThat(regionResolver.getRegion()).isSameAs(this.mockRegion);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void constructSingleRegionRegionResolverWithNullThrowsIllegalArgumentException() {
+
+		try {
+			new SingleRegionRegionResolver(null);
+		}
+		catch (IllegalArgumentException expected) {
+
+			assertThat(expected).hasMessage("Region must not be null");
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+	}
+
+	@Test
+	public void resolveReturnsConfiguredRegionMatchingName() {
+
+		when(this.mockRegion.getName()).thenReturn("MockRegion");
+
+		assertThat(new SingleRegionRegionResolver(this.mockRegion).resolve("MockRegion"))
+			.isEqualTo(this.mockRegion);
+
+		verify(this.mockRegion, times(1)).getName();
+	}
+
+	@Test
+	public void resolveReturnsNullWhenRegionNameDoesNotMatch() {
+
+		when(this.mockRegion.getName()).thenReturn("MockRegion");
+
+		SingleRegionRegionResolver regionResolver = new SingleRegionRegionResolver(this.mockRegion);
+
+		assertThat(regionResolver.resolve("TestRegion")).isNull();
+		assertThat(regionResolver.resolve("  ")).isNull();
+		assertThat(regionResolver.resolve("")).isNull();
+		assertThat(regionResolver.resolve(null)).isNull();
+
+		verify(this.mockRegion, times(4)).getName();
+	}
+}