Make RedisAccessor abstract.

Closes #2494
Original pull request: #2645

Author: jxblum

src/main/java/org/springframework/data/redis/core/RedisAccessor.java

@@ -29,7 +29,7 @@
  * @author John Blum
  * @see org.springframework.beans.factory.InitializingBean
  */
-public class RedisAccessor implements InitializingBean {
+public abstract class RedisAccessor implements InitializingBean {
 
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());

src/test/java/org/springframework/data/redis/core/RedisAccessorUnitTests.java

@@ -41,7 +41,7 @@ void setAndGetConnectionFactory() {
 
 		RedisConnectionFactory mockConnectionFactory = mock(RedisConnectionFactory.class);
 
-		RedisAccessor redisAccessor = new RedisAccessor();
+		RedisAccessor redisAccessor = new TestRedisAccessor();
 
 		assertThat(redisAccessor.getConnectionFactory()).isNull();
 
@@ -61,7 +61,7 @@ void setAndGetConnectionFactory() {
 	void getRequiredConnectionFactoryWhenNull() {
 
 		assertThatIllegalStateException()
-			.isThrownBy(() -> new RedisAccessor().getRequiredConnectionFactory())
+			.isThrownBy(() -> new TestRedisAccessor().getRequiredConnectionFactory())
 			.withMessage("RedisConnectionFactory is required")
 			.withNoCause();
 	}
@@ -71,7 +71,7 @@ void afterPropertiesSetCallsGetRequiredConnectionFactory() {
 
 		RedisConnectionFactory mockConnectionFactory = mock(RedisConnectionFactory.class);
 
-		RedisAccessor redisAccessor = spy(new RedisAccessor());
+		RedisAccessor redisAccessor = spy(new TestRedisAccessor());
 
 		doReturn(mockConnectionFactory).when(redisAccessor).getRequiredConnectionFactory();
 
@@ -81,4 +81,7 @@ void afterPropertiesSetCallsGetRequiredConnectionFactory() {
 		verify(redisAccessor, times(1)).getRequiredConnectionFactory();
 		verifyNoMoreInteractions(redisAccessor);
 	}
+
+	static class TestRedisAccessor extends RedisAccessor { }
+
 }