001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.impl.cloud;
018
019import java.util.List;
020
021import org.apache.camel.cloud.ServiceChooser;
022import org.apache.camel.cloud.ServiceDefinition;
023import org.apache.camel.util.ObjectHelper;
024
025public class RoundRobinServiceChooser implements ServiceChooser {
026    private int counter = -1;
027
028    @Override
029    public synchronized ServiceDefinition choose(List<ServiceDefinition> definitions) {
030        // Fail if the service definition list is null or empty
031        if (ObjectHelper.isEmpty(definitions)) {
032            throw new IllegalArgumentException("The ServiceDefinition list should not be empty");
033        }
034
035        int size = definitions.size();
036        if (size == 1 || ++counter >= size) {
037            counter = 0;
038        }
039
040        return definitions.get(counter);
041    }
042
043    @Override
044    public String toString() {
045        return "RoundRobinServiceChooser";
046    }
047}