FEATURE: Add CompletableFuture incr, decr API

Author: f1v3-dev

src/main/java/net/spy/memcached/v2/AsyncArcusCommands.java

@@ -59,6 +59,7 @@
 import net.spy.memcached.ops.CollectionInsertOperation;
 import net.spy.memcached.ops.ConcatenationType;
 import net.spy.memcached.ops.GetOperation;
+import net.spy.memcached.ops.Mutator;
 import net.spy.memcached.ops.GetsOperation;
 import net.spy.memcached.ops.Operation;
 import net.spy.memcached.ops.OperationCallback;
@@ -440,6 +441,70 @@ public void complete() {
     return future;
   }
 
+
+  public ArcusFuture<Long> incr(String key, int delta) {
+    return mutate(Mutator.incr, key, delta, -1L, 0);
+  }
+
+  public ArcusFuture<Long> incr(String key, int delta, long initial, int exp) {
+    if (initial < 0) {
+      throw new IllegalArgumentException("Initial value must be 0 or greater.");
+    }
+    return mutate(Mutator.incr, key, delta, initial, exp);
+  }
+
+  public ArcusFuture<Long> decr(String key, int delta) {
+    return mutate(Mutator.decr, key, delta, -1L, 0);
+  }
+
+  public ArcusFuture<Long> decr(String key, int delta, long initial, int exp) {
+    if (initial < 0) {
+      throw new IllegalArgumentException("Initial value must be 0 or greater.");
+    }
+    return mutate(Mutator.decr, key, delta, initial, exp);
+  }
+
+  private ArcusFuture<Long> mutate(Mutator mutator, String key, int delta, long initial, int exp) {
+    if (delta <= 0) {
+      throw new IllegalArgumentException("Delta must be greater than 0.");
+    }
+
+    AbstractArcusResult<Long> result = new AbstractArcusResult<>(new AtomicReference<>());
+    ArcusFutureImpl<Long> future = new ArcusFutureImpl<>(result);
+    ArcusClient client = arcusClientSupplier.get();
+
+    OperationCallback cb = new OperationCallback() {
+      @Override
+      public void receivedStatus(OperationStatus status) {
+        switch (status.getStatusCode()) {
+          case SUCCESS:
+            result.set(Long.parseLong(status.getMessage()));
+            break;
+          case ERR_NOT_FOUND:
+            result.set(-1L);
+            break;
+          case CANCELLED:
+            future.internalCancel();
+            break;
+          default:
+            // TYPE_MISMATCH or unknown statement
+            result.addError(key, status);
+            break;
+        }
+      }
+
+      @Override
+      public void complete() {
+        future.complete();
+      }
+    };
+    Operation op = client.getOpFact().mutate(mutator, key, delta, initial, exp, cb);
+    future.setOp(op);
+    client.addOp(key, op);
+
+    return future;
+  }
+
   public ArcusFuture<Map<String, CASValue<T>>> multiGets(List<String> keys) {
     ArcusClient client = arcusClientSupplier.get();
     Collection<Map.Entry<MemcachedNode, List<String>>> arrangedKeys

src/main/java/net/spy/memcached/v2/AsyncArcusCommandsIF.java

@@ -143,6 +143,52 @@ public interface AsyncArcusCommandsIF<T> {
    */
   ArcusFuture<Map<String, T>> multiGet(List<String> keys);
 
+  /**
+   * Increments a numeric value stored at the given key by {@code delta}.
+   *
+   * @param key   the key
+   * @param delta the amount to increment (&gt; 0)
+   * @return the new value after increment, or -1 if the key is not found
+   */
+  ArcusFuture<Long> incr(String key, int delta);
+
+  /**
+   * Increments a numeric value stored at the given key by {@code delta}.
+   * If the key does not exist,
+   * it is created with the value of {@code initial} and expiration time of {@code exp}.
+   *
+   * @param key     the key
+   * @param delta   the amount to increment (&gt; 0)
+   * @param initial the value to store if the key does not exist ({@code delta} is ignored) (&ge; 0)
+   * @param exp     expiration time in seconds, applied only when a new key is created
+   * @return the new value after increment, or {@code initial} if the key did not exist
+   */
+  ArcusFuture<Long> incr(String key, int delta, long initial, int exp);
+
+  /**
+   * Decrements a numeric value stored at the given key by {@code delta}.
+   * <p>If the value is decremented below 0, it will be set to 0.</p>
+   *
+   * @param key   the key
+   * @param delta the amount to decrement (&gt; 0)
+   * @return the new value after decrement, or -1 if the key is not found
+   */
+  ArcusFuture<Long> decr(String key, int delta);
+
+  /**
+   * Decrements a numeric value stored at the given key by {@code delta}.
+   * If the key does not exist,
+   * it is created with the value of {@code initial} and expiration time of {@code exp}.
+   * <p>If the value is decremented below 0, it will be set to 0.</p>
+   *
+   * @param key     the key
+   * @param delta   the amount to decrement (&gt; 0)
+   * @param initial the value to store if the key does not exist ({@code delta} is ignored) (&ge; 0)
+   * @param exp     expiration time in seconds, applied only when a new key is created
+   * @return the new value after decrement, or {@code initial} if the key did not exist
+   */
+  ArcusFuture<Long> decr(String key, int delta, long initial, int exp);
+
   /**
    * Get values with CAS for multiple keys.
    *