Java: JSON.MGET. (#2514)

* `JSON.MGET`.

Signed-off-by: Yury-Fridlyand <[email protected]>
Co-authored-by: James Xin <[email protected]>
Co-authored-by: Andrew Carbonetto <[email protected]>

Author: 3 people

CHANGELOG.md

@@ -27,6 +27,7 @@
 * Java: Added `FT.AGGREGATE` ([#2466](https://github.com/valkey-io/valkey-glide/pull/2466))
 * Java: Added `FT.PROFILE` ([#2473](https://github.com/valkey-io/valkey-glide/pull/2473))
 * Java: Added `JSON.SET` and `JSON.GET` ([#2462](https://github.com/valkey-io/valkey-glide/pull/2462))
+* Java: Added `JSON.MGET` ([#2514](https://github.com/valkey-io/valkey-glide/pull/2514))
 * Node: Added `FT.CREATE` ([#2501](https://github.com/valkey-io/valkey-glide/pull/2501))
 * Node: Added `FT.INFO` ([#2540](https://github.com/valkey-io/valkey-glide/pull/2540))
 * Node: Added `FT.AGGREGATE` ([#2554](https://github.com/valkey-io/valkey-glide/pull/2554))

java/client/src/main/java/glide/api/commands/servermodules/Json.java

@@ -2,6 +2,7 @@
 package glide.api.commands.servermodules;
 
 import static glide.api.models.GlideString.gs;
+import static glide.utils.ArrayTransformUtils.castArray;
 import static glide.utils.ArrayTransformUtils.concatenateArrays;
 
 import glide.api.BaseClient;
@@ -23,6 +24,7 @@ public class Json {
     private static final String JSON_PREFIX = "JSON.";
     private static final String JSON_SET = JSON_PREFIX + "SET";
     private static final String JSON_GET = JSON_PREFIX + "GET";
+    private static final String JSON_MGET = JSON_PREFIX + "MGET";
     private static final String JSON_NUMINCRBY = JSON_PREFIX + "NUMINCRBY";
     private static final String JSON_NUMMULTBY = JSON_PREFIX + "NUMMULTBY";
     private static final String JSON_ARRAPPEND = JSON_PREFIX + "ARRAPPEND";
@@ -413,6 +415,85 @@ public static CompletableFuture<GlideString> get(
                 new ArgsBuilder().add(gs(JSON_GET)).add(key).add(options.toArgs()).add(paths).toArray());
     }
 
+    /**
+     * Retrieves the JSON values at the specified <code>path</code> stored at multiple <code>keys
+     * </code>.
+     *
+     * @apiNote When in cluster mode, if keys in <code>keys</code> map to different hash slots, the
+     *     command will be split across these slots and executed separately for each. This means the
+     *     command is atomic only at the slot level. If one or more slot-specific requests fail, the
+     *     entire call will return the first encountered error, even though some requests may have
+     *     succeeded while others did not. If this behavior impacts your application logic, consider
+     *     splitting the request into sub-requests per slot to ensure atomicity.
+     * @param client The client to execute the command.
+     * @param keys The keys of the JSON documents.
+     * @param path The path within the JSON documents.
+     * @return An array with requested values for each key.
+     *     <ul>
+     *       <li>For JSONPath (path starts with <code>$</code>): Returns a stringified JSON list
+     *           replies for every possible path, or a string representation of an empty array, if
+     *           path doesn't exist.
+     *       <li>For legacy path (path doesn't start with <code>$</code>): Returns a string
+     *           representation of the value in <code>path</code>. If <code>path</code> doesn't exist,
+     *           the corresponding array element will be <code>null</code>.
+     *     </ul>
+     *     If a <code>key</code> doesn't exist, the corresponding array element will be <code>null
+     *     </code>.
+     * @example
+     *     <pre>{@code
+     * Json.set(client, "doc1", "$", "{\"a\": 1, \"b\": [\"one\", \"two\"]}").get();
+     * Json.set(client, "doc2", "$", "{\"a\": 1, \"c\": false}").get();
+     * var res = Json.mget(client, new String[] { "doc1", "doc2", "non_existing" }, "$.c").get();
+     * assert Arrays.equals(res, new String[] { "[]", "[false]", null });
+     * }</pre>
+     */
+    public static CompletableFuture<String[]> mget(
+            @NonNull BaseClient client, @NonNull String[] keys, @NonNull String path) {
+        return Json.<Object[]>executeCommand(
+                        client, concatenateArrays(new String[] {JSON_MGET}, keys, new String[] {path}))
+                .thenApply(res -> castArray(res, String.class));
+    }
+
+    /**
+     * Retrieves the JSON values at the specified <code>path</code> stored at multiple <code>keys
+     * </code>.
+     *
+     * @apiNote When in cluster mode, if keys in <code>keys</code> map to different hash slots, the
+     *     command will be split across these slots and executed separately for each. This means the
+     *     command is atomic only at the slot level. If one or more slot-specific requests fail, the
+     *     entire call will return the first encountered error, even though some requests may have
+     *     succeeded while others did not. If this behavior impacts your application logic, consider
+     *     splitting the request into sub-requests per slot to ensure atomicity.
+     * @param client The client to execute the command.
+     * @param keys The keys of the JSON documents.
+     * @param path The path within the JSON documents.
+     * @return An array with requested values for each key.
+     *     <ul>
+     *       <li>For JSONPath (path starts with <code>$</code>): Returns a stringified JSON list
+     *           replies for every possible path, or a string representation of an empty array, if
+     *           path doesn't exist.
+     *       <li>For legacy path (path doesn't start with <code>$</code>): Returns a string
+     *           representation of the value in <code>path</code>. If <code>path</code> doesn't exist,
+     *           the corresponding array element will be <code>null</code>.
+     *     </ul>
+     *     If a <code>key</code> doesn't exist, the corresponding array element will be <code>null
+     *     </code>.
+     * @example
+     *     <pre>{@code
+     * Json.set(client, "doc1", "$", "{\"a\": 1, \"b\": [\"one\", \"two\"]}").get();
+     * Json.set(client, "doc2", "$", "{\"a\": 1, \"c\": false}").get();
+     * var res = Json.mget(client, new GlideString[] { gs("doc1"), gs("doc2"), gs("doc3") }, gs("$.c")).get();
+     * assert Arrays.equals(res, new GlideString[] { gs("[]"), gs("[false]"), null });
+     * }</pre>
+     */
+    public static CompletableFuture<GlideString[]> mget(
+            @NonNull BaseClient client, @NonNull GlideString[] keys, @NonNull GlideString path) {
+        return Json.<Object[]>executeCommand(
+                        client,
+                        concatenateArrays(new GlideString[] {gs(JSON_MGET)}, keys, new GlideString[] {path}))
+                .thenApply(res -> castArray(res, GlideString.class));
+    }
+
     /**
      * Appends one or more <code>values</code> to the JSON array at the specified <code>path</code>
      * within the JSON document stored at <code>key</code>.

java/integTest/src/test/java/glide/modules/JsonTests.java

@@ -22,6 +22,7 @@
 import glide.api.models.commands.InfoOptions.Section;
 import glide.api.models.commands.json.JsonArrindexOptions;
 import glide.api.models.commands.json.JsonGetOptions;
+import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.ExecutionException;
 import lombok.SneakyThrows;
@@ -940,6 +941,28 @@ public void objkeys() {
         assertArrayEquals(new Object[] {gs("a"), gs("b")}, res);
     }
 
+    @Test
+    @SneakyThrows
+    public void mget() {
+        String key1 = UUID.randomUUID().toString();
+        String key2 = UUID.randomUUID().toString();
+        var data =
+                Map.of(
+                        key1, "{\"a\": 1, \"b\": [\"one\", \"two\"]}",
+                        key2, "{\"a\": 1, \"c\": false}");
+
+        for (var entry : data.entrySet()) {
+            assertEquals("OK", Json.set(client, entry.getKey(), "$", entry.getValue()).get());
+        }
+
+        var res1 =
+                Json.mget(client, new String[] {key1, key2, UUID.randomUUID().toString()}, "$.c").get();
+        assertArrayEquals(new String[] {"[]", "[false]", null}, res1);
+
+        var res2 = Json.mget(client, new GlideString[] {gs(key1), gs(key2)}, gs(".b[*]")).get();
+        assertArrayEquals(new GlideString[] {gs("\"one\""), null}, res2);
+    }
+
     @Test
     @SneakyThrows
     public void json_forget() {