Jagger
 All Classes Namespaces Files Functions Variables Enumerator Groups Pages
RandomLoadBalancer.java
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2010-2012 Grid Dynamics Consulting Services, Inc, All Rights Reserved
3  * http://www.griddynamics.com
4  *
5  * This library is free software; you can redistribute it and/or modify it under the terms of
6  * the Apache License; either
7  * version 2.0 of the License, or any later version.
8  *
9  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
10  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
11  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
12  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
13  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
14  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
15  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
16  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
17  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
18  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
19  */
20 
21 package com.griddynamics.jagger.invoker;
22 
23 import com.griddynamics.jagger.util.Pair;
24 
25 import com.google.common.collect.AbstractIterator;
26 
27 import java.util.Iterator;
28 import java.util.Random;
29 import java.util.concurrent.atomic.AtomicLong;
30 
41 public class RandomLoadBalancer<Q, E> extends PairSupplierFactoryLoadBalancer<Q, E> {
42 
43  private final AtomicLong randomSeed;
44 
45  public RandomLoadBalancer(long randomSeed, PairSupplierFactory<Q, E> pairSupplierFactory) {
46  super(pairSupplierFactory);
47  this.randomSeed = new AtomicLong(randomSeed);
48  }
49 
50  public long getRandomSeed() {
51  return randomSeed.get();
52  }
53 
59  @Override
60  public Iterator<Pair<Q, E>> provide() {
61 
62  return new AbstractIterator<Pair<Q,E>>() {
63 
64  private PairSupplier<Q, E> pairs = getPairSupplier();
65  private int size = pairs.size();
66  private Random random = new Random(randomSeed.getAndIncrement());
67 
68  @Override
69  protected Pair<Q, E> computeNext() {
70  return pairs.get(random.nextInt(size));
71  }
72 
73  @Override
74  public String toString() {
75  return "RandomLoadBalancer iterator";
76  }
77  };
78  }
79 }