Feature - add randomKeys() and randomEntries() methods to RMap object #3415

redisson/src/main/java/org/redisson/RedissonMap.java

@@ -568,6 +568,26 @@ public class RedissonMap<K, V> extends RedissonExpirable implements RMap<K, V> {
         return get(getAllAsync(keys));
     }
 
+    @Override
+    public Set<K> randomKeys(int count) {
+        return get(randomKeysAsync(count));
+    }
+
+    @Override
+    public Map<K, V> randomEntries(int count) {
+        return get(randomEntriesAsync(count));
+    }
+
+    @Override
+    public RFuture<Set<K>> randomKeysAsync(int count) {
+        return commandExecutor.readAsync(getName(), codec, RedisCommands.HRANDFIELD_KEYS, getName(), count);
+    }
+
+    @Override
+    public RFuture<Map<K, V>> randomEntriesAsync(int count) {
+        return commandExecutor.readAsync(getName(), codec, RedisCommands.HRANDFIELD, getName(), count, "WITHVALUES");
+    }
+
     @Override
     public RFuture<Map<K, V>> getAllAsync(Set<K> keys) {
         if (keys.isEmpty()) {

redisson/src/main/java/org/redisson/RedissonMapCache.java

@@ -2367,6 +2367,97 @@ public class RedissonMapCache<K, V> extends RedissonMap<K, V> implements RMapCac
                 System.currentTimeMillis());
     }
 
+    @Override
+    public RFuture<Set<K>> randomKeysAsync(int count) {
+        return commandExecutor.evalWriteAsync(getName(), codec, RedisCommands.EVAL_MAP_KEY_SET,
+            "local s = redis.call('hrandfield', KEYS[1], ARGV[2], 'withvalues'); " +
+                  "if s == false then " +
+                       "return {};" +
+                  "end; " +
+                  "local maxSize = tonumber(redis.call('hget', KEYS[5], 'max-size'));"
+                        + "local result = {}; "
+                        + "for i, v in ipairs(s) do "
+                            + "if i % 2 == 0 then "
+                                + "local t, val = struct.unpack('dLc0', v); "
+                                + "local key = s[i-1];" +
+                                "local expireDate = 92233720368547758; " +
+                                "local expireDateScore = redis.call('zscore', KEYS[2], key); "
+                                + "if expireDateScore ~= false then "
+                                + "expireDate = tonumber(expireDateScore) "
+                                + "end; "
+                                + "if t ~= 0 then "
+                                + "local expireIdle = redis.call('zscore', KEYS[3], key); "
+                                + "if expireIdle ~= false then "
+                                + "if tonumber(expireIdle) > tonumber(ARGV[1]) then "
+                                    + "redis.call('zadd', KEYS[3], t + tonumber(ARGV[1]), key); "
+                                    + "if maxSize ~= nil and maxSize ~= 0 then " +
+                                        "local mode = redis.call('hget', KEYS[5], 'mode'); " +
+                                        "if mode == false or mode == 'LRU' then " +
+                                            "redis.call('zadd', KEYS[4], tonumber(ARGV[1]), key); " +
+                                        "else " +
+                                            "redis.call('zincrby', KEYS[4], 1, key); " +
+                                        "end; "
+                                    + "end; "
+                                + "end; "
+                                + "expireDate = math.min(expireDate, tonumber(expireIdle)) "
+                                + "end; "
+                                + "end; "
+                                + "if expireDate > tonumber(ARGV[1]) then "
+                                    + "table.insert(result, key); "
+                                + "end; "
+                            + "end; "
+                        + "end;" +
+                        "return result;",
+                Arrays.asList(getName(), getTimeoutSetName(), getIdleSetName(), getLastAccessTimeSetName(), getOptionsName()),
+                System.currentTimeMillis(), count);
+    }
+
+    @Override
+    public RFuture<Map<K, V>> randomEntriesAsync(int count) {
+        return commandExecutor.evalWriteAsync(getName(), codec, RedisCommands.EVAL_MAP,
+            "local s = redis.call('hrandfield', KEYS[1], ARGV[2], 'withvalues'); " +
+                "if s == false then " +
+                    "return {};" +
+                "end; "
+                + "local result = {}; "
+                + "local maxSize = tonumber(redis.call('hget', KEYS[5], 'max-size'));"
+                + "for i, v in ipairs(s) do "
+                    + "if i % 2 == 0 then "
+                      + "local t, val = struct.unpack('dLc0', v); "
+                      + "local key = s[i-1];" +
+                        "local expireDate = 92233720368547758; " +
+                        "local expireDateScore = redis.call('zscore', KEYS[2], key); "
+                        + "if expireDateScore ~= false then "
+                            + "expireDate = tonumber(expireDateScore) "
+                        + "end; "
+                        + "if t ~= 0 then "
+                            + "local expireIdle = redis.call('zscore', KEYS[3], key); "
+                            + "if expireIdle ~= false then "
+                                + "if tonumber(expireIdle) > tonumber(ARGV[1]) then "
+                                    + "redis.call('zadd', KEYS[3], t + tonumber(ARGV[1]), key); "
+                                            + "if maxSize ~= nil and maxSize ~= 0 then " +
+                                                    "local mode = redis.call('hget', KEYS[5], 'mode'); " +
+                                                    "if mode == false or mode == 'LRU' then " +
+                                                        "redis.call('zadd', KEYS[4], tonumber(ARGV[1]), key); " +
+                                                    "else " +
+                                                        "redis.call('zincrby', KEYS[4], 1, key); " +
+                                                    "end; "
+                                            + "end; "
+                                        + "end; "
+                                        + "expireDate = math.min(expireDate, tonumber(expireIdle)) "
+                                    + "end; "
+                                + "end; "
+                                + "if expireDate > tonumber(ARGV[1]) then "
+                                    + "table.insert(result, key); "
+                                    + "table.insert(result, val); "
+                                + "end; "
+                            + "end; "
+                        + "end;" +
+                        "return result;",
+                Arrays.asList(getName(), getTimeoutSetName(), getIdleSetName(), getLastAccessTimeSetName(), getOptionsName()),
+                System.currentTimeMillis(), count);
+    }
+
     @Override
     public RFuture<Set<java.util.Map.Entry<K, V>>> readAllEntrySetAsync() {
         return readAll(RedisCommands.EVAL_MAP_ENTRY);

redisson/src/main/java/org/redisson/api/RMap.java

@@ -107,6 +107,22 @@ public interface RMap<K, V> extends ConcurrentMap<K, V>, RExpirable, RMapAsync<K
      */
     V putIfExists(K key, V value);
 
+    /**
+     * Returns random keys from this map limited by <code>count</code>
+     *
+     * @param count - keys amount to return
+     * @return random keys
+     */
+    Set<K> randomKeys(int count);
+
+    /**
+     * Returns random map entries from this map limited by <code>count</code>
+     *
+     * @param count - entries amount to return
+     * @return random entries
+     */
+    Map<K, V> randomEntries(int count);
+
     /**
      * Returns <code>RMapReduce</code> object associated with this map
      * 

redisson/src/main/java/org/redisson/api/RMapAsync.java

@@ -145,6 +145,22 @@ public interface RMapAsync<K, V> extends RExpirableAsync {
      */
     RFuture<Void> putAllAsync(Map<? extends K, ? extends V> map, int batchSize);
 
+    /**
+     * Returns random keys from this map limited by <code>count</code>
+     *
+     * @param count - keys amount to return
+     * @return random keys
+     */
+    RFuture<Set<K>> randomKeysAsync(int count);
+
+    /**
+     * Returns random map entries from this map limited by <code>count</code>
+     *
+     * @param count - entries amount to return
+     * @return random entries
+     */
+    RFuture<Map<K, V>> randomEntriesAsync(int count);
+
     /**
      * Adds the given <code>delta</code> to the current value
      * by mapped <code>key</code>.

redisson/src/main/java/org/redisson/api/RMapReactive.java

@@ -347,6 +347,22 @@ public interface RMapReactive<K, V> extends RExpirableReactive {
      */
     Mono<V> putIfExists(K key, V value);
 
+    /**
+     * Returns random keys from this map limited by <code>count</code>
+     *
+     * @param count - keys amount to return
+     * @return random keys
+     */
+    Mono<Set<K>> randomKeys(int count);
+
+    /**
+     * Returns random map entries from this map limited by <code>count</code>
+     *
+     * @param count - entries amount to return
+     * @return random entries
+     */
+    Mono<Map<K, V>> randomEntries(int count);
+
     /**
      * Stores the specified <code>value</code> mapped by <code>key</code>
      * only if mapping already exists.

redisson/src/main/java/org/redisson/api/RMapRx.java

@@ -350,6 +350,22 @@ public interface RMapRx<K, V> extends RExpirableRx {
      */
     Maybe<V> putIfExists(K key, V value);
 
+    /**
+     * Returns random keys from this map limited by <code>count</code>
+     *
+     * @param count - keys amount to return
+     * @return random keys
+     */
+    Single<Set<K>> randomKeys(int count);
+
+    /**
+     * Returns random map entries from this map limited by <code>count</code>
+     *
+     * @param count - entries amount to return
+     * @return random entries
+     */
+    Single<Map<K, V>> randomEntries(int count);
+
     /**
      * Stores the specified <code>value</code> mapped by <code>key</code>
      * only if mapping already exists.

redisson/src/main/java/org/redisson/client/protocol/RedisCommand.java

@@ -87,7 +87,7 @@ public class RedisCommand<R> {
     }
 
     public RedisCommand(String name, Convertor<R> convertor) {
-        this(name, null, null, null);
+        this(name, (String) null, null, null);
         this.convertor = convertor;
     }
 
@@ -104,6 +104,12 @@ public class RedisCommand<R> {
         this.outParamType = outParamType;
     }
 
+    public RedisCommand(String name, MultiDecoder<R> replayMultiDecoder, ValueType outParamType, Convertor convertor) {
+        this(name, null, replayMultiDecoder);
+        this.outParamType = outParamType;
+        this.convertor = convertor;
+    }
+
     public RedisCommand(String name, MultiDecoder<R> replayMultiDecoder) {
         this(name, null, replayMultiDecoder);
     }

redisson/src/main/java/org/redisson/client/protocol/RedisCommands.java

@@ -21,25 +21,7 @@ import org.redisson.api.StreamInfo;
 import org.redisson.api.StreamMessageId;
 import org.redisson.client.codec.StringCodec;
 import org.redisson.client.protocol.RedisCommand.ValueType;
-import org.redisson.client.protocol.convertor.BitsSizeReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanAmountReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanNotNullReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanNullReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanNullSafeReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanNumberReplayConvertor;
-import org.redisson.client.protocol.convertor.BooleanReplayConvertor;
-import org.redisson.client.protocol.convertor.ByteReplayConvertor;
-import org.redisson.client.protocol.convertor.DoubleNullSafeReplayConvertor;
-import org.redisson.client.protocol.convertor.DoubleReplayConvertor;
-import org.redisson.client.protocol.convertor.IntegerReplayConvertor;
-import org.redisson.client.protocol.convertor.LongReplayConvertor;
-import org.redisson.client.protocol.convertor.ShortReplayConvertor;
-import org.redisson.client.protocol.convertor.StreamIdConvertor;
-import org.redisson.client.protocol.convertor.StringToListConvertor;
-import org.redisson.client.protocol.convertor.TimeObjectDecoder;
-import org.redisson.client.protocol.convertor.TrueReplayConvertor;
-import org.redisson.client.protocol.convertor.TypeConvertor;
-import org.redisson.client.protocol.convertor.VoidReplayConvertor;
+import org.redisson.client.protocol.convertor.*;
 import org.redisson.client.protocol.decoder.*;
 import org.redisson.client.protocol.pubsub.PubSubStatusDecoder;
 import org.redisson.cluster.ClusterNodeInfo;
@@ -289,6 +271,8 @@ public interface RedisCommands {
     RedisStrictCommand<Void> HSET_VOID = new RedisStrictCommand<Void>("HSET", new VoidReplayConvertor());
     RedisCommand<MapScanResult<Object, Object>> HSCAN = new RedisCommand<MapScanResult<Object, Object>>("HSCAN", 
             new ListMultiDecoder2(new MapScanResultReplayDecoder(), new ObjectMapReplayDecoder()), ValueType.MAP);
+    RedisCommand<Map<Object, Object>> HRANDFIELD = new RedisCommand<Map<Object, Object>>("HRANDFIELD", new ObjectMapReplayDecoder(), ValueType.MAP, new EmptyMapConvertor());
+    RedisCommand<Set<Object>> HRANDFIELD_KEYS = new RedisCommand<>("HRANDFIELD", new ObjectSetReplayDecoder<>(), ValueType.MAP_KEY, new EmptySetConvertor());
     RedisCommand<Map<Object, Object>> HGETALL = new RedisCommand<Map<Object, Object>>("HGETALL", new ObjectMapReplayDecoder(), ValueType.MAP);
     RedisCommand<Set<Entry<Object, Object>>> HGETALL_ENTRY = new RedisCommand<Set<Entry<Object, Object>>>("HGETALL", new ObjectMapEntryReplayDecoder(), ValueType.MAP);
     RedisCommand<List<Object>> HVALS = new RedisCommand<List<Object>>("HVALS", new ObjectListReplayDecoder<Object>(), ValueType.MAP_VALUE);

redisson/src/main/java/org/redisson/client/protocol/convertor/EmptyMapConvertor.java

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2013-2020 Nikita Koksharov
+ *
+ * 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
+ *
+ *    http://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.redisson.client.protocol.convertor;
+
+import java.util.Collections;
+
+/**
+ * @author Nikita Koksharov
+ */
+public class EmptyMapConvertor implements Convertor<Object> {
+
+    @Override
+    public Object convert(Object obj) {
+        if (obj == null) {
+            return Collections.emptyMap();
+        }
+        return obj;
+    }
+
+}

redisson/src/main/java/org/redisson/client/protocol/convertor/EmptySetConvertor.java

@@ -0,0 +1,33 @@
+/**
+ * Copyright (c) 2013-2020 Nikita Koksharov
+ *
+ * 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
+ *
+ *    http://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.redisson.client.protocol.convertor;
+
+import java.util.Collections;
+
+/**
+ * @author Nikita Koksharov
+ */
+public class EmptySetConvertor implements Convertor<Object> {
+
+    @Override
+    public Object convert(Object obj) {
+        if (obj == null) {
+            return Collections.emptySet();
+        }
+        return obj;
+    }
+
+}

redisson/src/test/java/org/redisson/BaseMapTest.java

@@ -132,6 +132,32 @@ public abstract class BaseMapTest extends BaseTest {
         }
     }
 
+    @Test
+    public void testRandomKeys() {
+        RMap<Integer, Integer> map = getMap("map");
+        Set<Integer> e1 = map.randomKeys(1);
+        assertThat(e1).isEmpty();
+        map.put(1, 11);
+        map.put(2, 21);
+        map.put(3, 31);
+        map.put(4, 41);
+        Set<Integer> e = map.randomKeys(2);
+        assertThat(e).containsAnyOf(1, 2, 3, 4).hasSize(2);
+    }
+
+    @Test
+    public void testRandomEntries() {
+        RMap<Integer, Integer> map = getMap("map");
+        Map<Integer, Integer> e1 = map.randomEntries(1);
+        assertThat(e1).isEmpty();
+        map.put(1, 11);
+        map.put(2, 21);
+        map.put(3, 31);
+        map.put(4, 41);
+        Map<Integer, Integer> e = map.randomEntries(2);
+        assertThat(e.keySet()).containsAnyOf(1, 2, 3, 4).hasSize(2);
+    }
+
     @Test
     public void testComputeIfPresent() {
         RMap<String, String> map = getMap("map");