Feature - availablePermits method added to RSemaphore object. #2537

redisson/src/main/java/org/redisson/RedissonRateLimiter.java

@@ -255,5 +255,16 @@ public class RedissonRateLimiter extends RedissonObject implements RRateLimiter
     public RFuture<RateLimiterConfig> getConfigAsync() {
         return commandExecutor.readAsync(getName(), StringCodec.INSTANCE, HGETALL, getName());
     }
-    
+
+    @Override
+    public long availablePermits() {
+        return get(availablePermitsAsync());
+    }
+
+    @Override
+    public RFuture<Long> availablePermitsAsync() {
+        return commandExecutor.writeAsync(getName(), LongCodec.INSTANCE, RedisCommands.GET_LONG, getValueName());
+    }
+
+
 }

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

@@ -147,5 +147,12 @@ public interface RRateLimiter extends RRateLimiterAsync, RObject {
      * @return config object
      */
     RateLimiterConfig getConfig();
-    
+
+    /**
+     * Returns amount of available permits.
+     *
+     * @return number of permits
+     */
+    long availablePermits();
+
 }

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

@@ -149,5 +149,12 @@ public interface RRateLimiterAsync extends RObjectAsync {
      * @return config object
      */
     RFuture<RateLimiterConfig> getConfigAsync();
-    
+
+    /**
+     * Returns amount of available permits.
+     *
+     * @return number of permits
+     */
+    RFuture<Long> availablePermitsAsync();
+
 }

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

@@ -15,10 +15,10 @@
  */
 package org.redisson.api;
 
-import java.util.concurrent.TimeUnit;
-
 import reactor.core.publisher.Mono;
 
+import java.util.concurrent.TimeUnit;
+
 /**
  * Reactive interface for Redis based Rate Limiter object.
  * 
@@ -144,5 +144,12 @@ public interface RRateLimiterReactive extends RObjectReactive {
      *         if the waiting time elapsed before a permit was acquired
      */
     Mono<Boolean> tryAcquire(long permits, long timeout, TimeUnit unit);
-    
+
+    /**
+     * Returns amount of available permits.
+     *
+     * @return number of permits
+     */
+    Mono<Long> availablePermits();
+
 }

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

@@ -15,11 +15,11 @@
  */
 package org.redisson.api;
 
-import java.util.concurrent.TimeUnit;
-
 import io.reactivex.Completable;
 import io.reactivex.Single;
 
+import java.util.concurrent.TimeUnit;
+
 /**
  * Reactive interface for Redis based Rate Limiter object.
  * 
@@ -145,5 +145,12 @@ public interface RRateLimiterRx extends RObjectRx {
      *         if the waiting time elapsed before a permit was acquired
      */
     Single<Boolean> tryAcquire(long permits, long timeout, TimeUnit unit);
-    
+
+    /**
+     * Returns amount of available permits.
+     *
+     * @return number of permits
+     */
+    Single<Long> availablePermits();
+
 }

redisson/src/test/java/org/redisson/RedissonRateLimiterTest.java

@@ -41,14 +41,19 @@ public class RedissonRateLimiterTest extends BaseTest {
     @Test
     public void testZeroTimeout() throws InterruptedException {
         RRateLimiter limiter = redisson.getRateLimiter("myLimiter");
+        assertThat(limiter.availablePermits()).isEqualTo(0);
         limiter.trySetRate(RateType.OVERALL, 5, 1, RateIntervalUnit.SECONDS);
         
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isTrue();
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isTrue();
+        assertThat(limiter.availablePermits()).isEqualTo(3);
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isTrue();
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isTrue();
+        assertThat(limiter.availablePermits()).isEqualTo(1);
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isTrue();
-        
+
+        assertThat(limiter.availablePermits()).isEqualTo(0);
+
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isFalse();
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isFalse();
         assertThat(limiter.tryAcquire(1, 0, TimeUnit.SECONDS)).isFalse();