DATAKV-34

+ improve handling of collections during pipeline/multi operations

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/connection/DefaultStringRedisConnection.java

@@ -594,6 +594,10 @@ public class DefaultStringRedisConnection implements StringRedisConnection {
 
 
 	private List<String> deserialize(Collection<byte[]> data) {
+		if (data == null) {
+			return null;
+		}
+
 		List<String> result = new ArrayList<String>(data.size());
 		for (byte[] raw : data) {
 			result.add(serializer.deserialize(raw));
@@ -602,6 +606,10 @@ public class DefaultStringRedisConnection implements StringRedisConnection {
 	}
 
 	private Set<String> deserialize(Set<byte[]> data) {
+		if (data == null) {
+			return null;
+		}
+
 		Set<String> result = new LinkedHashSet<String>(data.size());
 		for (byte[] raw : data) {
 			result.add(serializer.deserialize(raw));
@@ -614,6 +622,9 @@ public class DefaultStringRedisConnection implements StringRedisConnection {
 	}
 
 	private Set<StringTuple> deserializeTuple(Set<Tuple> data) {
+		if (data == null) {
+			return null;
+		}
 		Set<StringTuple> result = new LinkedHashSet<StringTuple>(data.size());
 		for (Tuple raw : data) {
 			result.add(new DefaultStringTuple(raw, serializer.deserialize(raw.getValue())));

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/AbstractOperations.java

@@ -146,6 +146,11 @@ abstract class AbstractOperations<K, V> {
 
 	@SuppressWarnings("unchecked")
 	<HK, HV> Map<HK, HV> deserializeHashMap(Map<byte[], byte[]> entries) {
+		// connection in pipeline/multi mode
+		if (entries == null) {
+			return null;
+		}
+
 		Map<HK, HV> map = new LinkedHashMap<HK, HV>(entries.size());
 
 		for (Map.Entry<byte[], byte[]> entry : entries.entrySet()) {

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/core/SerializationUtils.java

@@ -39,6 +39,11 @@ public abstract class SerializationUtils {
 
 	@SuppressWarnings("unchecked")
 	static <T extends Collection<?>> T deserializeValues(Collection<byte[]> rawValues, Class<T> type, RedisSerializer<?> redisSerializer) {
+		// connection in pipeline/multi mode
+		if (rawValues == null) {
+			return null;
+		}
+
 		Collection<Object> values = (List.class.isAssignableFrom(type) ? new ArrayList<Object>(rawValues.size())
 				: new LinkedHashSet<Object>(rawValues.size()));
 		for (byte[] bs : rawValues) {

spring-data-redis/src/test/java/org/springframework/data/keyvalue/redis/connection/AbstractConnectionIntegrationTests.java

@@ -162,4 +162,12 @@ public abstract class AbstractConnectionIntegrationTests {
 		assertNull(multiGet.get(0));
 		assertNull(multiGet.get(1));
 	}
+
+	@Test
+	public void testNullCollections() throws Exception {
+		connection.openPipeline();
+		assertNull(connection.keys("~*"));
+		assertNull(connection.hKeys("~"));
+		connection.closePipeline();
+	}
 }

spring-data-redis/src/test/java/org/springframework/data/keyvalue/redis/connection/jredis/JRedisConnectionIntegrationTests.java

@@ -70,4 +70,8 @@ public class JRedisConnectionIntegrationTests extends AbstractConnectionIntegrat
 	@Ignore("JRedis has connecting issues with null")
 	public void testNullKey() {
 	}
+
+	@Ignore("JRedis does not support pipelining")
+	public void testNullCollections() {
+	}
 }