Added part of the 'String Commands' group to RedisClient as specified on the official Redis website.

java/client/src/main/java/glide/api/BaseClient.java

@@ -65,6 +65,60 @@ protected static String handleStringResponse(Response response) {
                         + " expected String");
     }
 
+    /**
+     * Extracts the response value from the Redis response and either throws an exception or returns
+     * the value as a Long.
+     *
+     * @param response Redis protobuf message
+     * @return Response as a Long
+     */
+    public static Long handleLongResponse(Response response) {
+        Object value = handleObjectResponse(response);
+        if (value instanceof Long) {
+            return (Long) value;
+        }
+        throw new RedisException(
+                "Unexpected return type from Redis: got "
+                        + value.getClass().getSimpleName()
+                        + " expected Long");
+    }
+
+    /**
+     * Extracts the response value from the Redis response and either throws an exception or returns
+     * the value as a Double.
+     *
+     * @param response Redis protobuf message
+     * @return Response as a Double
+     */
+    public static Double handleDoubleResponse(Response response) {
+        Object value = handleObjectResponse(response);
+        if (value instanceof Double) {
+            return (Double) value;
+        }
+        throw new RedisException(
+                "Unexpected return type from Redis: got "
+                        + value.getClass().getSimpleName()
+                        + " expected Double");
+    }
+
+    /**
+     * Extracts the response value from the Redis response and either throws an exception or returns
+     * the value as an Object Array.
+     *
+     * @param response Redis protobuf message
+     * @return Response as an Object Array
+     */
+    public static Object[] handleObjectArrayResponse(Response response) {
+        Object value = handleObjectResponse(response);
+        if (value instanceof Object[]) {
+            return (Object[]) value;
+        }
+        throw new RedisException(
+                "Unexpected return type from Redis: got "
+                        + value.getClass().getSimpleName()
+                        + " expected Object Array");
+    }
+
     /**
      * Extracts the response value from the Redis response and either throws an exception or returns
      * the * value as a HashMap

java/client/src/main/java/glide/api/RedisClient.java

@@ -15,6 +15,8 @@
 import glide.managers.CommandManager;
 import glide.managers.ConnectionManager;
 import glide.managers.models.Command;
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CompletableFuture;
@@ -201,4 +203,142 @@ public CompletableFuture<String> set(String key, String value, SetOptions option
                         .build();
         return commandManager.submitNewCommand(command, BaseClient::handleStringResponse);
     }
+
+    /**
+     * Decrements the number stored at `key` by one. If `key` does not exist, it is set to 0 before
+     * performing the operation.
+     *
+     * @see <a href="https://redis.io/commands/decr/">redis.io</a> for details.
+     * @param key - The key to decrement its value.
+     * @return the value of `key` after the decrement. An error is raised if `key` contains a value of
+     *     the wrong type or contains a string that can not be represented as integer.
+     */
+    @Override
+    public CompletableFuture<Long> decr(String key) {
+        Command command =
+                Command.builder()
+                        .requestType(Command.RequestType.DECR)
+                        .arguments(new String[] {key})
+                        .build();
+        return commandManager.submitNewCommand(command, BaseClient::handleLongResponse);
+    }
+
+    /**
+     * Decrements the number stored at `key` by `amount`. If `key` does not exist, it is set to 0
+     * before performing the operation.
+     *
+     * @see <a href="https://redis.io/commands/decrby/">redis.io</a> for details.
+     * @param key - The key to decrement its value.
+     * @param amount - The amount to decrement.
+     * @return the value of `key` after the decrement. An error is raised if `key` contains a value of
+     *     the wrong type or contains a string that can not be represented as integer.
+     */
+    @Override
+    public CompletableFuture<Long> decrBy(String key, long amount) {
+        Command command =
+                Command.builder()
+                        .requestType(Command.RequestType.DECR_BY)
+                        .arguments(new String[] {key, Long.toString(amount)})
+                        .build();
+        return commandManager.submitNewCommand(command, BaseClient::handleLongResponse);
+    }
+
+    /**
+     * Increments the number stored at `key` by one. If `key` does not exist, it is set to 0 before
+     * performing the operation.
+     *
+     * @see <a href="https://redis.io/commands/incr/">redis.io</a> for details.
+     * @param key - The key to increment its value.
+     * @return the value of `key` after the increment, An error is raised if `key` contains a value of
+     *     the wrong type or contains a string that can not be represented as integer.
+     */
+    @Override
+    public CompletableFuture<Long> incr(String key) {
+        Command command =
+                Command.builder()
+                        .requestType(Command.RequestType.INCR)
+                        .arguments(new String[] {key})
+                        .build();
+        return commandManager.submitNewCommand(command, BaseClient::handleLongResponse);
+    }
+
+    /**
+     * Increments the number stored at `key` by `amount`. If `key` does not exist, it is set to 0
+     * before performing the operation.
+     *
+     * @see <a href="https://redis.io/commands/incrby/">redis.io</a> for details.
+     * @param key - The key to increment its value.
+     * @param amount - The amount to increment.
+     * @returns the value of `key` after the increment, An error is raised if `key` contains a value
+     *     of the wrong type or contains a string that can not be represented as integer.
+     */
+    @Override
+    public CompletableFuture<Long> incrBy(String key, long amount) {
+        Command command =
+                Command.builder()
+                        .requestType(Command.RequestType.INCR_BY)
+                        .arguments(new String[] {key, Long.toString(amount)})
+                        .build();
+        return commandManager.submitNewCommand(command, BaseClient::handleLongResponse);
+    }
+
+    /**
+     * Increment the string representing a floating point number stored at `key` by `amount`. By using
+     * a negative increment value, the result is that the value stored at `key` is decremented. If
+     * `key` does not exist, it is set to 0 before performing the operation.
+     *
+     * @see <a href="https://redis.io/commands/incrbyfloat/">redis.io</a> for details.
+     * @param key - The key to increment its value.
+     * @param amount - The amount to increment.
+     * @returns the value of `key` after the increment. An error is raised if `key` contains a value
+     *     of the wrong type, or the current key content is not parsable as a double precision
+     *     floating point number.
+     */
+    @Override
+    public CompletableFuture<Double> incrByFloat(String key, double amount) {
+        Command command =
+                Command.builder()
+                        .requestType(Command.RequestType.INCR_BY_FLOAT)
+                        .arguments(new String[] {key, Double.toString(amount)})
+                        .build();
+        return commandManager.submitNewCommand(command, BaseClient::handleDoubleResponse);
+    }
+
+    /**
+     * Retrieve the values of multiple keys.
+     *
+     * @see <a href="https://redis.io/commands/mget/">redis.io</a> for details.
+     * @param keys - A list of keys to retrieve values for.
+     * @returns A list of values corresponding to the provided keys. If a key is not found, its
+     *     corresponding value in the list will be null.
+     */
+    @Override
+    public CompletableFuture<Object[]> mget(String[] keys) {
+        Command command =
+                Command.builder().requestType(Command.RequestType.MGET).arguments(keys).build();
+        return commandManager.submitNewCommand(command, BaseClient::handleObjectArrayResponse);
+    }
+
+    /**
+     * Set multiple keys to multiple values in a single operation.
+     *
+     * @see <a href="https://redis.io/commands/mset/">redis.io</a> for details.
+     * @param keyValueMap - A key-value map consisting of keys and their respective values to set.
+     * @returns null
+     */
+    @Override
+    public CompletableFuture<Void> mset(HashMap<String, String> keyValueMap) {
+        List<String> flatMap = new ArrayList<>();
+
+        for (Map.Entry<String, String> entry : keyValueMap.entrySet()) {
+            flatMap.add(entry.getKey());
+            flatMap.add(entry.getValue());
+        }
+
+        String[] args = flatMap.toArray(new String[0]);
+
+        Command command =
+                Command.builder().requestType(Command.RequestType.MSET).arguments(args).build();
+        return commandManager.submitNewCommand(command, BaseClient::handleVoidResponse);
+    }
 }

java/client/src/main/java/glide/api/commands/StringCommands.java

@@ -1,14 +1,33 @@
 package glide.api.commands;
 
 import glide.api.models.commands.SetOptions;
+import java.util.HashMap;
 import java.util.concurrent.CompletableFuture;
 
-/** String Commands interface to handle single commands that return Strings. */
+/**
+ * String Commands interface.
+ *
+ * @see: <a href="https://redis.io/commands/?group=string">String Commands</a>
+ */
 public interface StringCommands {
 
     CompletableFuture<String> get(String key);
 
     CompletableFuture<Void> set(String key, String value);
 
     CompletableFuture<String> set(String key, String value, SetOptions options);
+
+    CompletableFuture<Long> decr(String key);
+
+    CompletableFuture<Long> decrBy(String key, long amount);
+
+    CompletableFuture<Long> incr(String key);
+
+    CompletableFuture<Long> incrBy(String key, long amount);
+
+    CompletableFuture<Double> incrByFloat(String key, double amount);
+
+    CompletableFuture<Object[]> mget(String[] keys);
+
+    CompletableFuture<Void> mset(HashMap<String, String> keyValueMap);
 }

java/client/src/main/java/glide/managers/CommandManager.java

@@ -76,6 +76,20 @@ private RequestType mapRequestTypes(Command.RequestType inType) {
                 return RequestType.GetString;
             case SET_STRING:
                 return RequestType.SetString;
+            case DECR:
+                return RequestType.Decr;
+            case DECR_BY:
+                return RequestType.DecrBy;
+            case INCR:
+                return RequestType.Incr;
+            case INCR_BY:
+                return RequestType.IncrBy;
+            case INCR_BY_FLOAT:
+                return RequestType.IncrByFloat;
+            case MGET:
+                return RequestType.MGet;
+            case MSET:
+                return RequestType.MSet;
         }
         throw new RuntimeException("Unsupported request type");
     }

java/client/src/main/java/glide/managers/models/Command.java

@@ -44,5 +44,61 @@ public enum RequestType {
          * @see: <href=https://redis.io/commands/set/>command reference</a>
          */
         SET_STRING,
+
+        /**
+         * Decrement the number stored at `key` by one. If the key does not exist, it is set to 0 before
+         * performing the operation.
+         *
+         * @see <a href="https://redis.io/commands/decr/">redis.io</a> for details.
+         */
+        DECR,
+
+        /**
+         * Decrements the number stored at `key` by `amount`. If `key` does not exist, it is set to 0
+         * before performing the operation. Sets the specified fields to their respective values in the
+         * hash stored at `key`.
+         *
+         * @see <a href="https://redis.io/commands/decrby/">redis.io</a> for details.
+         */
+        DECR_BY,
+
+        /**
+         * Increments the number stored at `key` by one. If `key` does not exist, it is set to 0 before
+         * performing the operation.
+         *
+         * @see <a href="https://redis.io/commands/incr/">redis.io</a> for details.
+         */
+        INCR,
+
+        /**
+         * Increments the number stored at `key` by `amount`. If `key` does not exist, it is set to 0
+         * before performing the operation.
+         *
+         * @see <a href="https://redis.io/commands/incrby/">redis.io</a> for details.
+         */
+        INCR_BY,
+
+        /**
+         * Increment the string representing a floating point number stored at `key` by `amount`. By
+         * using a negative increment value, the result is that the value stored at `key` is
+         * decremented. If `key` does not exist, it is set to 0 before performing the operation.
+         *
+         * @see <a href="https://redis.io/commands/incrbyfloat/">redis.io</a> for details.
+         */
+        INCR_BY_FLOAT,
+
+        /**
+         * Retrieve the values of multiple keys.
+         *
+         * @see <a href="https://redis.io/commands/mget/">redis.io</a> for details.
+         */
+        MGET,
+
+        /**
+         * Set multiple keys to multiple values in a single operation.
+         *
+         * @see <a href="https://redis.io/commands/mset/">redis.io</a> for details.
+         */
+        MSET,
     }
 }