/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.util.concurrent;

import io.netty.util.internal.UnstableApi;

import java.util.concurrent.atomic.AtomicInteger;

/**
 * Default implementation which uses simple round-robin to choose next {@link EventExecutor}.
 */
@UnstableApi
public final class DefaultEventExecutorChooserFactory implements EventExecutorChooserFactory {

    public static final DefaultEventExecutorChooserFactory INSTANCE = new DefaultEventExecutorChooserFactory();

    private DefaultEventExecutorChooserFactory() { }

    @SuppressWarnings("unchecked")
    @Override
    public EventExecutorChooser newChooser(EventExecutor[] executors) {
        if (isPowerOfTwo(executors.length)) {
            return new PowerOfTwoEventExecutorChooser(executors);
        } else {
            return new GenericEventExecutorChooser(executors);
        }
    }

    private static boolean isPowerOfTwo(int val) {
        return (val & -val) == val;
    }

    private static final class PowerOfTwoEventExecutorChooser implements EventExecutorChooser {
        private final AtomicInteger idx = new AtomicInteger();
        private final EventExecutor[] executors;

        PowerOfTwoEventExecutorChooser(EventExecutor[] executors) {
            this.executors = executors;
        }

        @Override
        public EventExecutor next() {
            return executors[idx.getAndIncrement() & executors.length - 1];
        }
    }

    private static final class GenericEventExecutorChooser implements EventExecutorChooser {
        private final AtomicInteger idx = new AtomicInteger();
        private final EventExecutor[] executors;

        GenericEventExecutorChooser(EventExecutor[] executors) {
            this.executors = executors;
        }

        @Override
        public EventExecutor next() {
            return executors[Math.abs(idx.getAndIncrement() % executors.length)];
        }
    }
}

@@ -756,16 +756,63 @@
 Integer;
+%0Aimport java.util.concurrent.atomic.AtomicLong;
 %0A%0A/**%0A *
@@ -1187,43 +1187,8 @@
  %7D%0A%0A
-    @SuppressWarnings(%22unchecked%22)%0A
     
@@ -2154,35 +2154,278 @@
     
-private final AtomicInteger
+// Use a 'long' counter to avoid non-round-robin behaviour at the 32-bit overflow boundary.%0A        // The 64-bit long solves this by placing the overflow so far into the future, that no system%0A        // will encounter this in practice.%0A        private final AtomicLong
  idx
@@ -2429,39 +2429,36 @@
 idx = new Atomic
-Integer
+Long
 ();%0A        priv
@@ -2659,32 +2659,32 @@
 ecutor next() %7B%0A
-
             retu
@@ -2696,16 +2696,22 @@
 ecutors%5B
+(int) 
 Math.abs

Fix overflow bug in GenericEventExecutorChooser (#10468)