com.hazelcast.client.util.RoundRobinLB Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2016, Hazelcast, Inc. All Rights Reserved.
*
* Licensed 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 com.hazelcast.client.util;
import com.hazelcast.core.Member;
import java.util.concurrent.atomic.AtomicInteger;
/**
* A {@link com.hazelcast.client.LoadBalancer} implementation that relies on using round robin
* to a next member to send a request to.
*
* Round robin is done based on best effort basis, the order of members for concurrent calls to
* the {@link #next()} is not guaranteed.
*/
public class RoundRobinLB extends AbstractLoadBalancer {
private final AtomicInteger indexRef;
public RoundRobinLB() {
this((int) System.nanoTime());
}
public RoundRobinLB(int seed) {
indexRef = new AtomicInteger(seed);
}
@Override
public Member next() {
Member[] members = getMembers();
if (members == null || members.length == 0) {
return null;
}
int length = members.length;
int index = (indexRef.getAndAdd(1) % length + length) % length;
return members[index];
}
}