    001    /*
    002     * Copyright 2009 Red Hat, Inc.
    003     * Red Hat licenses this file to you under the Apache License, version
    004     * 2.0 (the "License"); you may not use this file except in compliance
    005     * with the License.  You may obtain a copy of the License at
    006     *    http://www.apache.org/licenses/LICENSE-2.0
    007     * Unless required by applicable law or agreed to in writing, software
    008     * distributed under the License is distributed on an "AS IS" BASIS,
    009     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
    010     * implied.  See the License for the specific language governing
    011     * permissions and limitations under the License.
    012     */
    013
    014    package org.hornetq.api.core.client.loadbalance;
    015
    016    import org.hornetq.utils.Random;
    017
    018    /**
    019     * RoundRobinConnectionLoadBalancingPolicy corresponds to a round-robin load-balancing policy.
    020     *
    021     * <br>
    022     * The first call to {@link #select(int)} will return a random integer between {@code 0} (inclusive) and {@code max} (exclusive).
    023     * Subsequent calls will then return an integer in a round-robin fashion.
    024     *
    025     * @author <a href="mailto:tim.fox@jboss.com">Tim Fox</a>
    026     *
    027     * Created 28 Nov 2008 10:21:08
    028     *
    029     *
    030     */
    031    public class RoundRobinConnectionLoadBalancingPolicy implements ConnectionLoadBalancingPolicy
    032    {
    033       private final Random random = new Random();
    034
    035       private boolean first = true;
    036
    037       private int pos;
    038
    039       public int select(final int max)
    040       {
    041          if (first)
    042          {
    043             // We start on a random one
    044             pos = random.getRandom().nextInt(max);
    045
    046             first = false;
    047          }
    048          else
    049          {
    050             pos++;
    051
    052             if (pos >= max)
    053             {
    054                pos = 0;
    055             }
    056          }
    057
    058          return pos;
    059       }
    060    }