Feature - RLiveObjectService.count() method implemented. #2785

redisson/src/main/java/org/redisson/RedissonLiveObjectService.java

@@ -138,6 +138,12 @@ public class RedissonLiveObjectService implements RLiveObjectService {
                     .collect(Collectors.toList());
     }
 
+    @Override
+    public long count(Class<?> entityClass, Condition condition) {
+        Set<Object> ids = seachEngine.find(entityClass, condition);
+        return ids.size();
+    }
+
     @Override
     public <T> T attach(T detachedObject) {
         validateDetached(detachedObject);

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

@@ -70,6 +70,22 @@ public interface RLiveObjectService {
      */
     <T> Collection<T> find(Class<T> entityClass, Condition condition);
 
+    /**
+     * Counts the entities matches specified <code>condition</code>.
+     * Usage example:
+     * <pre>
+     * long objectsAmount = liveObjectService.count(MyObject.class, Conditions.or(Conditions.in("field", "value1", "value2"),
+     *                          Conditions.and(Conditions.eq("field2", "value2"), Conditions.eq("field3", "value5"))));
+     * </pre>
+     *
+     * @see Conditions
+     *
+     * @param entityClass - entity class
+     * @param condition - condition object
+     * @return amount of live objects.
+     */
+    long count(Class<?> entityClass, Condition condition);
+
     /**
      * Returns iterator for all entry ids by specified <code>entityClass</code>.
      * Ids traversed with SCAN operation. Each SCAN operation loads