/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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 org.apache.beam.sdk.io.kinesis;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.collect.Queues.newArrayDeque;
import java.util.Deque;
import java.util.Iterator;
/**
* Very simple implementation of round robin algorithm.
*/
class RoundRobin<T> implements Iterable<T> {
private final Deque<T> deque;
public RoundRobin(Iterable<T> collection) {
this.deque = newArrayDeque(collection);
checkArgument(!deque.isEmpty(), "Tried to initialize RoundRobin with empty collection");
}
public T getCurrent() {
return deque.getFirst();
}
public void moveForward() {
deque.addLast(deque.removeFirst());
}
public int size() {
return deque.size();
}
@Override
public Iterator<T> iterator() {
return deque.iterator();
}
}