Polishing.

Add documentation for generics. Fix remove() and element() methods to adhere to their contract.

See #2602
Original pull request: #2608

src/main/java/org/springframework/data/redis/support/collections/RedisCollection.java

@@ -20,6 +20,7 @@ import java.util.Collection;
 /**
  * Redis extension for the {@link Collection} contract.
  *
+ * @param <E> the type of elements in this collection.
  * @author Costin Leau
  */
 public interface RedisCollection<E> extends RedisStore {

src/main/java/org/springframework/data/redis/support/collections/RedisIterator.java

@@ -22,6 +22,7 @@ import org.springframework.lang.Nullable;
 /**
  * Iterator extension for Redis collection removal.
  *
+ * @param <E> the type of elements in this collection.
  * @author Costin Leau
  */
 abstract class RedisIterator<E> implements Iterator<E> {
@@ -43,6 +44,7 @@ abstract class RedisIterator<E> implements Iterator<E> {
 	 * @return
 	 * @see java.util.Iterator#hasNext()
 	 */
+	@Override
 	public boolean hasNext() {
 		return delegate.hasNext();
 	}
@@ -51,6 +53,7 @@ abstract class RedisIterator<E> implements Iterator<E> {
 	 * @return
 	 * @see java.util.Iterator#next()
 	 */
+	@Override
 	public E next() {
 		item = delegate.next();
 		return item;
@@ -59,6 +62,7 @@ abstract class RedisIterator<E> implements Iterator<E> {
 	/**
 	 * @see java.util.Iterator#remove()
 	 */
+	@Override
 	public void remove() {
 		delegate.remove();
 		removeFromRedisStorage(item);

src/main/java/org/springframework/data/redis/support/collections/RedisList.java

@@ -15,7 +15,7 @@
  */
 package org.springframework.data.redis.support.collections;
 
-import static org.springframework.data.redis.connection.RedisListCommands.Direction;
+import static org.springframework.data.redis.connection.RedisListCommands.*;
 
 import java.time.Duration;
 import java.util.Deque;
@@ -34,6 +34,7 @@ import org.springframework.util.Assert;
  * Redis extension for the {@link List} contract. Supports {@link List}, {@link Queue} and {@link Deque} contracts as
  * well as their equivalent blocking siblings {@link BlockingDeque} and {@link BlockingDeque}.
  *
+ * @param <E> the type of elements in this collection.
  * @author Costin Leau
  * @author Mark Paluch
  * @author John Blum

src/main/java/org/springframework/data/redis/support/collections/RedisSet.java

@@ -24,6 +24,7 @@ import org.springframework.data.redis.core.RedisOperations;
 /**
  * Redis extension for the {@link Set} contract. Supports {@link Set} specific operations backed by Redis operations.
  *
+ * @param <E> the type of elements in this collection.
  * @author Costin Leau
  * @author Christoph Strobl
  * @author Mark Paluch

src/main/java/org/springframework/data/redis/support/collections/RedisZSet.java

@@ -36,6 +36,7 @@ import org.springframework.data.redis.core.ZSetOperations.TypedTuple;
  * <p>
  * Since using a {@link Comparator} does not apply, a ZSet implements the {@link SortedSet} methods where applicable.
  *
+ * @param <E> the type of elements in this collection.
  * @author Costin Leau
  * @author Mark Paluch
  * @author Christoph Strobl

src/main/java/org/springframework/data/redis/support/collections/ReversedRedisListView.java

@@ -15,18 +15,7 @@
  */
 package org.springframework.data.redis.support.collections;
 
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Date;
-import java.util.Iterator;
-import java.util.List;
-import java.util.ListIterator;
-import java.util.NoSuchElementException;
-import java.util.Objects;
-import java.util.Spliterator;
-import java.util.Spliterators;
+import java.util.*;
 import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 import java.util.function.IntFunction;
@@ -44,9 +33,9 @@ import org.springframework.lang.Nullable;
  * Implementation and view of an existing {@link RedisList} where the elements in the list (deque) are returned in
  * reverse order.
  *
+ * @param <E> the type of elements in this collection.
  * @author John Blum
  * @author Mark Paluch
- * @param <E> {@link Class type} of the {@link Object elements} contained in the underlying, wrapped {@link RedisList}.
  * @since 3.2
  */
 class ReversedRedisListView<E> implements RedisList<E> {
@@ -176,7 +165,7 @@ class ReversedRedisListView<E> implements RedisList<E> {
 	public boolean addAll(Collection<? extends E> collection) {
 
 		return !org.springframework.util.CollectionUtils.isEmpty(collection)
-			&& this.base.addAll(0, Arrays.asList(reverse((E[]) collection.toArray())));
+				&& this.base.addAll(0, Arrays.asList(reverse((E[]) collection.toArray())));
 	}
 
 	@Override
@@ -430,7 +419,13 @@ class ReversedRedisListView<E> implements RedisList<E> {
 
 	@Override
 	public E element() {
-		return peekLast();
+
+		E value = peek();
+		if (value == null) {
+			throw new NoSuchElementException();
+		}
+
+		return value;
 	}
 
 	@Override
@@ -603,7 +598,13 @@ class ReversedRedisListView<E> implements RedisList<E> {
 
 	@Override
 	public E remove() {
-		return pollLast();
+
+		E value = poll();
+		if (value == null) {
+			throw new NoSuchElementException();
+		}
+
+		return value;
 	}
 
 	@Override