Add support for type using the SCAN command.

We now support the type argument for Keyspace scanning through KeyScanOptions.type.

Closes: #2089
Original Pull Request: #2109

src/main/java/org/springframework/data/redis/connection/ReactiveKeyCommands.java

@@ -30,6 +30,7 @@ import org.springframework.data.redis.connection.ReactiveRedisConnection.Command
 import org.springframework.data.redis.connection.ReactiveRedisConnection.KeyCommand;
 import org.springframework.data.redis.connection.ReactiveRedisConnection.MultiValueResponse;
 import org.springframework.data.redis.connection.ReactiveRedisConnection.NumericResponse;
+import org.springframework.data.redis.core.KeyScanOptions;
 import org.springframework.data.redis.core.ScanOptions;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -268,6 +269,20 @@ public interface ReactiveKeyCommands {
 		return scan(ScanOptions.NONE);
 	}
 
+	/**
+	 * Use a {@link Flux} to iterate over keys. The resulting {@link Flux} acts as a cursor and issues {@code SCAN}
+	 * commands itself as long as the subscriber signals demand.
+	 *
+	 * @param options must not be {@literal null}.
+	 * @return the {@link Flux} emitting {@link ByteBuffer keys} one by one.
+	 * @throws IllegalArgumentException when options is {@literal null}.
+	 * @see <a href="https://redis.io/commands/scan">Redis Documentation: SCAN</a>
+	 * @since 2.6
+	 */
+	default Flux<ByteBuffer> scan(KeyScanOptions options) {
+		return scan((ScanOptions) options);
+	}
+
 	/**
 	 * Use a {@link Flux} to iterate over keys. The resulting {@link Flux} acts as a cursor and issues {@code SCAN}
 	 * commands itself as long as the subscriber signals demand.

src/main/java/org/springframework/data/redis/connection/RedisKeyCommands.java

@@ -21,6 +21,7 @@ import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
 import org.springframework.data.redis.core.Cursor;
+import org.springframework.data.redis.core.KeyScanOptions;
 import org.springframework.data.redis.core.ScanOptions;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -128,6 +129,18 @@ public interface RedisKeyCommands {
 	@Nullable
 	Set<byte[]> keys(byte[] pattern);
 
+	/**
+	 * Use a {@link Cursor} to iterate over keys.
+	 *
+	 * @param options must not be {@literal null}.
+	 * @return never {@literal null}.
+	 * @since 2.4
+	 * @see <a href="https://redis.io/commands/scan">Redis Documentation: SCAN</a>
+	 */
+	default Cursor<byte[]> scan(KeyScanOptions options) {
+		return scan((ScanOptions) options);
+	}
+
 	/**
 	 * Use a {@link Cursor} to iterate over keys.
 	 *

src/main/java/org/springframework/data/redis/connection/jedis/JedisKeyCommands.java

@@ -32,6 +32,7 @@ import org.springframework.data.redis.connection.ValueEncoding;
 import org.springframework.data.redis.connection.ValueEncoding.RedisValueEncoding;
 import org.springframework.data.redis.connection.convert.Converters;
 import org.springframework.data.redis.core.Cursor;
+import org.springframework.data.redis.core.KeyScanOptions;
 import org.springframework.data.redis.core.ScanCursor;
 import org.springframework.data.redis.core.ScanIteration;
 import org.springframework.data.redis.core.ScanOptions;
@@ -171,6 +172,10 @@ class JedisKeyCommands implements RedisKeyCommands {
 	 */
 	public Cursor<byte[]> scan(long cursorId, ScanOptions options) {
 
+		if (options instanceof KeyScanOptions && ((KeyScanOptions) options).getType() != null) {
+			throw new UnsupportedOperationException("'SCAN' with type is not yet supported using the Jedis driver");
+		}
+
 		return new ScanCursor<byte[]>(cursorId, options) {
 
 			@Override

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConverters.java

@@ -65,6 +65,7 @@ import org.springframework.data.redis.connection.convert.Converters;
 import org.springframework.data.redis.connection.convert.ListConverter;
 import org.springframework.data.redis.connection.convert.LongToBooleanConverter;
 import org.springframework.data.redis.connection.convert.StringToRedisClientInfoConverter;
+import org.springframework.data.redis.core.KeyScanOptions;
 import org.springframework.data.redis.core.ScanOptions;
 import org.springframework.data.redis.core.types.Expiration;
 import org.springframework.data.redis.core.types.RedisClientInfo;
@@ -906,7 +907,7 @@ public abstract class LettuceConverters extends Converters {
 			return null;
 		}
 
-		ScanArgs scanArgs = new ScanArgs();
+		KeyScanArgs scanArgs = new KeyScanArgs();
 
 		byte[] pattern = options.getBytePattern();
 		if (pattern != null) {
@@ -917,6 +918,10 @@ public abstract class LettuceConverters extends Converters {
 			scanArgs.limit(options.getCount());
 		}
 
+		if (options instanceof KeyScanOptions) {
+			scanArgs.type(((KeyScanOptions) options).getType());
+		}
+
 		return scanArgs;
 	}
 

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

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2014-2021 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.redis.core;
+
+import java.util.StringJoiner;
+
+import org.springframework.lang.Nullable;
+import org.springframework.util.StringUtils;
+
+/**
+ * Options to be used for with {@literal SCAN} commands.
+ *
+ * @author Mark Paluch
+ * @since 2.6
+ */
+public class KeyScanOptions extends ScanOptions {
+
+	/**
+	 * Constant to apply default {@link KeyScanOptions} without setting a limit or matching a pattern.
+	 */
+	public static KeyScanOptions NONE = new KeyScanOptions(null, null, null, null);
+
+	private final @Nullable String type;
+
+	private KeyScanOptions(@Nullable Long count, @Nullable String pattern, @Nullable byte[] bytePattern,
+			@Nullable String type) {
+
+		super(count, pattern, bytePattern);
+		this.type = type;
+	}
+
+	/**
+	 * Static factory method that returns a new {@link KeyScanOptionsBuilder}.
+	 *
+	 * @return
+	 */
+	public static KeyScanOptionsBuilder scanOptions() {
+		return new KeyScanOptionsBuilder();
+	}
+
+	@Nullable
+	public String getType() {
+		return type;
+	}
+
+	@Override
+	public String toOptionString() {
+
+		if (this.equals(KeyScanOptions.NONE)) {
+			return "";
+		}
+
+		StringJoiner joiner = new StringJoiner(", ").add(super.toOptionString());
+
+		if (StringUtils.hasText(type)) {
+			joiner.add("'type' '" + type + "'");
+		}
+
+		return joiner.toString();
+	}
+
+	public static class KeyScanOptionsBuilder extends ScanOptionsBuilder {
+
+		private @Nullable String type;
+
+		private KeyScanOptionsBuilder() {}
+
+		/**
+		 * Returns the current {@link KeyScanOptionsBuilder} configured with the given {@code count}.
+		 *
+		 * @param count
+		 * @return
+		 */
+		@Override
+		public KeyScanOptionsBuilder count(long count) {
+			super.count(count);
+			return this;
+		}
+
+		/**
+		 * Returns the current {@link KeyScanOptionsBuilder} configured with the given {@code pattern}.
+		 *
+		 * @param pattern
+		 * @return
+		 */
+		@Override
+		public KeyScanOptionsBuilder match(String pattern) {
+			super.match(pattern);
+			return this;
+		}
+
+		/**
+		 * Returns the current {@link KeyScanOptionsBuilder} configured with the given {@code pattern}.
+		 *
+		 * @param pattern
+		 * @return
+		 */
+		@Override
+		public KeyScanOptionsBuilder match(byte[] pattern) {
+			super.match(pattern);
+			return this;
+		}
+
+		/**
+		 * Returns the current {@link KeyScanOptionsBuilder} configured with the given {@code type}.
+		 *
+		 * @param type
+		 * @return
+		 */
+		public KeyScanOptionsBuilder type(String type) {
+			this.type = type;
+			return this;
+		}
+
+		/**
+		 * Builds a new {@link KeyScanOptions} objects.
+		 *
+		 * @return a new {@link KeyScanOptions} objects.
+		 */
+		@Override
+		public KeyScanOptions build() {
+			return new KeyScanOptions(count, pattern, bytePattern, type);
+		}
+	}
+}

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

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.redis.core;
 
+import java.util.StringJoiner;
+
 import org.springframework.lang.Nullable;
 import org.springframework.util.StringUtils;
 
@@ -25,6 +27,7 @@ import org.springframework.util.StringUtils;
  * @author Thomas Darimont
  * @author Mark Paluch
  * @since 1.4
+ * @see KeyScanOptions
  */
 public class ScanOptions {
 
@@ -37,14 +40,14 @@ public class ScanOptions {
 	private final @Nullable String pattern;
 	private final @Nullable byte[] bytePattern;
 
-	private ScanOptions(@Nullable Long count, @Nullable String pattern, @Nullable byte[] bytePattern) {
+	ScanOptions(@Nullable Long count, @Nullable String pattern, @Nullable byte[] bytePattern) {
 		this.count = count;
 		this.pattern = pattern;
 		this.bytePattern = bytePattern;
 	}
 
 	/**
-	 * Static factory method that returns a new {@link ScanOptionsBuilder}.
+	 * Static factory method that returns a new {@link ScanOptionsBuilder}.
 	 *
 	 * @return
 	 */
@@ -83,17 +86,18 @@ public class ScanOptions {
 			return "";
 		}
 
-		String params = "";
+		StringJoiner joiner = new StringJoiner(", ");
 
-		if (this.count != null) {
-			params += (", 'count', " + count);
+		if (this.getCount() != null) {
+			joiner.add("'count' " + this.getCount());
 		}
+
 		String pattern = getPattern();
 		if (StringUtils.hasText(pattern)) {
-			params += (", 'match' , '" + this.pattern + "'");
+			joiner.add("'match' '" + pattern + "'");
 		}
 
-		return params;
+		return joiner.toString();
 	}
 
 	/**
@@ -103,10 +107,11 @@ public class ScanOptions {
 	 */
 	public static class ScanOptionsBuilder {
 
-		private @Nullable Long count;
-		private @Nullable String pattern;
-		private @Nullable byte[] bytePattern;
+		@Nullable Long count;
+		@Nullable String pattern;
+		@Nullable byte[] bytePattern;
 
+		ScanOptionsBuilder() {}
 
 		/**
 		 * Returns the current {@link ScanOptionsBuilder} configured with the given {@code count}.