Added test cases to test and assert the correct behavior of the StringBasedGemfireRepositoryQuery.toCollection(..) method for handling various GemFire Select Query result types.

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

@@ -21,21 +21,31 @@ import org.springframework.util.Assert;
 
 /**
  * Base class for GemFire specific {@link RepositoryQuery} implementations.
- * 
+ * <p/>
  * @author Oliver Gierke
  * @author David Turanski
+ * @author John Blum
+ * @see org.springframework.data.gemfire.repository.query.GemfireQueryMethod
+ * @see org.springframework.data.repository.query.RepositoryQuery
  */
 abstract class GemfireRepositoryQuery implements RepositoryQuery {
 
 	private final GemfireQueryMethod queryMethod;
 
+	/*
+	 * (non-Javadoc)
+	 * Constructor used for testing purposes only!
+	 */
+	GemfireRepositoryQuery() {
+		queryMethod = null;
+	}
+
 	/**
 	 * Creates a new {@link GemfireRepositoryQuery} using the given {@link GemfireQueryMethod}.
 	 * 
 	 * @param queryMethod must not be {@literal null}.
 	 */
 	public GemfireRepositoryQuery(GemfireQueryMethod queryMethod) {
-
 		Assert.notNull(queryMethod);
 		this.queryMethod = queryMethod;
 	}
@@ -48,4 +58,5 @@ abstract class GemfireRepositoryQuery implements RepositoryQuery {
 	public QueryMethod getQueryMethod() {
 		return this.queryMethod;
 	}
+
 }

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

@@ -15,9 +15,9 @@
  */
 package org.springframework.data.gemfire.repository.query;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Iterator;
 
 import org.springframework.dao.IncorrectResultSizeDataAccessException;
 import org.springframework.data.gemfire.GemfireTemplate;
@@ -28,13 +28,13 @@ import org.springframework.util.StringUtils;
 
 import com.gemstone.gemfire.cache.query.SelectResults;
 import com.gemstone.gemfire.cache.query.internal.ResultsBag;
-import com.gemstone.gemfire.cache.query.internal.ResultsCollectionPdxDeserializerWrapper;
 
 /**
  * {@link GemfireRepositoryQuery} using plain {@link String} based OQL queries.
- * 
+ * <p/>
  * @author Oliver Gierke
  * @author David Turanski
+ * @author John Blum
  */
 public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 
@@ -44,6 +44,16 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 	private final GemfireQueryMethod method;
 	private final GemfireTemplate template;
 
+	/*
+	 * (non-Javadoc)
+	 * Constructor used for testing purposes only!
+	 */
+	StringBasedGemfireRepositoryQuery() {
+		query = null;
+		method = null;
+		template = null;
+	}
+
 	/**
 	 * Creates a new {@link StringBasedGemfireRepositoryQuery} using the given {@link GemfireQueryMethod} and
 	 * {@link GemfireTemplate}. The actual query {@link String} will be looked up from the query method.
@@ -85,13 +95,11 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 	 */
 	@Override
 	public Object execute(Object[] parameters) {
-
 		ParametersParameterAccessor accessor = new ParametersParameterAccessor(method.getParameters(), parameters);
 		QueryString query = this.query.forRegion(method.getEntityInformation().getJavaType(), template.getRegion());
 
-		Iterator<Integer> indexes = query.getInParameterIndexes().iterator();
-		while (indexes.hasNext()) {
-			query = query.bindIn(toCollection(accessor.getBindableValue(indexes.next() - 1)));
+		for (Integer index : query.getInParameterIndexes()) {
+			query = query.bindIn(toCollection(accessor.getBindableValue(index - 1)));
 		}
 
 		Collection<?> result = toCollection(template.find(query.toString(), parameters));
@@ -112,27 +120,33 @@ public class StringBasedGemfireRepositoryQuery extends GemfireRepositoryQuery {
 	}
 
 	/**
-	 * Returns the given object as collection. Collections will be returned as is, Arrays will be converted into a
-	 * collection and all other objects will be wrapped into a single-element collection.
-	 * 
-	 * @param source
-	 * @return
+	 * Returns the given object as a Collection. Collections will be returned as is, Arrays will be converted into a
+	 * Collection and all other objects will be wrapped into a single-element Collection.
+	 * <p/>
+	 * @param source the resulting object from the GemFire Query.
+	 * @return the querying resulting object as a Collection.
+	 * @see java.util.Arrays#asList(Object[])
+	 * @see java.util.Collection
+	 * @see org.springframework.util.CollectionUtils#arrayToList(Object)
 	 */
-	private Collection<?> toCollection(Object source) {
-
+	Collection<?> toCollection(Object source) {
 		if (source instanceof SelectResults) {
 			return ((SelectResults) source).asList();
 		}
 
 		if (source instanceof ResultsBag) {
-			ResultsBag bag = (ResultsBag) source;
-			return bag.asList();
+			return ((ResultsBag) source).asList();
 		}
 
 		if (source instanceof Collection) {
 			return (Collection<?>) source;
 		}
 
-		return source.getClass().isArray() ? CollectionUtils.arrayToList(source) : Collections.singleton(source);
+		if (source == null) {
+			return Collections.emptyList();
+		}
+
+		return (source.getClass().isArray() ? CollectionUtils.arrayToList(source) : Arrays.asList(source));
 	}
+
 }

src/test/java/org/springframework/data/gemfire/repository/query/StringBasedGemfireRepositoryQueryTest.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2010-2013 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.gemfire.repository.query;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNotSame;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+import org.junit.Test;
+
+import com.gemstone.gemfire.cache.query.SelectResults;
+import com.gemstone.gemfire.cache.query.internal.ResultsBag;
+
+/**
+ * The SpringBasedGemfireRepositoryQueryTest class is a test suite of test cases testing the contract and functionality
+ * of the StringBasedGemfireRepositoryQuery class.
+ * <p/>
+ * @author John Blum
+ * @see org.mockito.Mockito
+ * @see org.junit.Test
+ * @see org.springframework.data.gemfire.repository.query.StringBasedGemfireRepositoryQuery
+ * @since 1.4.0
+ */
+public class StringBasedGemfireRepositoryQueryTest {
+
+	private final StringBasedGemfireRepositoryQuery repositoryQuery = new StringBasedGemfireRepositoryQuery();
+
+	@Test
+	public void testToCollectionWithSelectResults() {
+		SelectResults mockSelectResults = mock(SelectResults.class, "testToCollectionWithSelectResults.SelectResults");
+		List<String> expectedList = Arrays.asList("one", "two", "three");
+
+		when(mockSelectResults.asList()).thenReturn(expectedList);
+
+		Collection<?> actualList = repositoryQuery.toCollection(mockSelectResults);
+
+		assertSame(expectedList, actualList);
+	}
+
+	@Test
+	public void testToCollectionWithResultsBag() {
+		ResultsBag mockResultsBag = mock(ResultsBag.class, "testToCollectionWithResultsBag.ResultsBag");
+		List<String> expectedList = Arrays.asList("a", "b", "c");
+
+		when(mockResultsBag.asList()).thenReturn(expectedList);
+
+		Collection<?> actualList = repositoryQuery.toCollection(mockResultsBag);
+
+		assertSame(expectedList, actualList);
+	}
+
+	@Test
+	public void testToCollectionWithCollection() {
+		List<String> expectedList = Arrays.asList("x", "y", "z");
+		Collection<?> actualList = repositoryQuery.toCollection(expectedList);
+
+		assertSame(expectedList, actualList);
+	}
+
+	@Test
+	public void testToCollectionWithArray() {
+		Object[] array = { 1, 2, 3 };
+		Collection<?> list = repositoryQuery.toCollection(array);
+
+		assertNotNull(list);
+		assertNotSame(array, list);
+		assertTrue(list instanceof List);
+		assertEquals(array.length, list.size());
+		assertTrue(list.containsAll(Arrays.asList(array)));
+	}
+
+	@Test
+	public void testToCollectionWithSingleObject() {
+		Collection<?> list = repositoryQuery.toCollection("test");
+
+		assertTrue(list instanceof List);
+		assertFalse(list.isEmpty());
+		assertEquals(1, list.size());
+		assertEquals("test", ((List) list).get(0));
+	}
+
+	@Test
+	public void testToCollectionWithNull() {
+		Collection<?> list = repositoryQuery.toCollection(null);
+
+		assertNotNull(list);
+		assertTrue(list.isEmpty());
+	}
+
+}