Feature - RRingBuffer.setCapacity() method added #3056

redisson/src/main/java/org/redisson/RedissonRingBuffer.java

@@ -62,7 +62,21 @@ public class RedissonRingBuffer<V> extends RedissonQueue<V> implements RRingBuff
     public boolean trySetCapacity(int capacity) {
         return get(trySetCapacityAsync(capacity));
     }
-    
+
+    @Override
+    public RFuture<Void> setCapacityAsync(int capacity) {
+        return commandExecutor.evalWriteAsync(getName(), LongCodec.INSTANCE, RedisCommands.EVAL_VOID,
+                "redis.call('set', KEYS[2], ARGV[1]); " +
+                      "local len = redis.call('llen', KEYS[1]); " +
+                      "redis.call('ltrim', KEYS[1], len - tonumber(ARGV[1]), len - 1); ",
+             Arrays.asList(getName(), settingsName), capacity);
+    }
+
+    @Override
+    public void setCapacity(int capacity) {
+        get(setCapacityAsync(capacity));
+    }
+
     @Override
     public RFuture<Boolean> addAsync(V e) {
         return commandExecutor.evalWriteAsync(getName(), LongCodec.INSTANCE, RedisCommands.EVAL_BOOLEAN,

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

@@ -29,14 +29,22 @@ package org.redisson.api;
 public interface RRingBuffer<V> extends RQueue<V>, RRingBufferAsync<V> {
 
     /**
-     * Sets queue capacity only if it is not set before.
+     * Sets capacity of the queue only if it wasn't set before.
      *
      * @param capacity - queue capacity
      * @return <code>true</code> if capacity set successfully
      *         <code>false</code> if capacity already set
      */
     boolean trySetCapacity(int capacity);
-    
+
+    /**
+     * Sets capacity of the queue and overrides current value.
+     * Trims queue if previous capacity value was greater than new.
+     *
+     * @param capacity - queue capacity
+     */
+    void setCapacity(int capacity);
+
     /**
      * Returns remaining capacity of this queue
      * 

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

@@ -29,14 +29,22 @@ package org.redisson.api;
 public interface RRingBufferAsync<V> extends RQueueAsync<V> {
 
     /**
-     * Sets queue capacity only if it is not set before.
+     * Sets capacity of the queue only if it wasn't set before.
      *
      * @param capacity - queue capacity
      * @return <code>true</code> if capacity set successfully
      *         <code>false</code> if capacity already set
      */
     RFuture<Boolean> trySetCapacityAsync(int capacity);
-    
+
+    /**
+     * Sets capacity of the queue and overrides current value.
+     * Trims queue if previous capacity value was greater than new.
+     *
+     * @param capacity - queue capacity
+     */
+    RFuture<Void> setCapacityAsync(int capacity);
+
     /**
      * Returns remaining capacity of this queue
      * 

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

@@ -38,7 +38,15 @@ public interface RRingBufferReactive<V> extends RQueueReactive<V> {
      *         <code>false</code> if capacity already set
      */
     Mono<Boolean> trySetCapacity(int capacity);
-    
+
+    /**
+     * Sets capacity of the queue and overrides current value.
+     * Trims queue if previous capacity value was greater than new.
+     *
+     * @param capacity - queue capacity
+     */
+    Mono<Void> setCapacity(int capacity);
+
     /**
      * Returns remaining capacity of this queue
      * 

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

@@ -15,6 +15,7 @@
  */
 package org.redisson.api;
 
+import io.reactivex.Completable;
 import io.reactivex.Single;
 
 /**
@@ -38,7 +39,15 @@ public interface RRingBufferRx<V> extends RQueueRx<V> {
      *         <code>false</code> if capacity already set
      */
     Single<Boolean> trySetCapacity(int capacity);
-    
+
+    /**
+     * Sets capacity of the queue and overrides current value.
+     * Trims queue if previous capacity value was greater than new.
+     *
+     * @param capacity - queue capacity
+     */
+    Completable setCapacity(int capacity);
+
     /**
      * Returns remaining capacity of this queue
      * 

redisson/src/test/java/org/redisson/RedissonRingBufferTest.java

@@ -10,6 +10,27 @@ import org.redisson.api.RRingBuffer;
 
 public class RedissonRingBufferTest extends BaseTest {
 
+    @Test
+    public void testSetCapacity() {
+        RRingBuffer<Integer> buffer = redisson.getRingBuffer("test");
+        buffer.trySetCapacity(5);
+        for (int i = 0; i < 10; i++) {
+            buffer.add(i);
+        }
+
+        assertThat(buffer).containsExactly(5, 6, 7, 8, 9);
+        buffer.setCapacity(3);
+        assertThat(buffer).containsExactly(7, 8, 9);
+
+        RRingBuffer<Integer> buffer2 = redisson.getRingBuffer("test2");
+        buffer2.setCapacity(3);
+        for (int i = 0; i < 10; i++) {
+            buffer2.add(i);
+        }
+        assertThat(buffer2).containsExactly(7, 8, 9);
+
+    }
+
     @Test
     public void testAdd() {
         RRingBuffer<Integer> buffer = redisson.getRingBuffer("test");