#region License Information /* HeuristicLab * Copyright (C) 2002-2015 Heuristic and Evolutionary Algorithms Laboratory (HEAL) * * This file is part of HeuristicLab. * * HeuristicLab is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * HeuristicLab is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with HeuristicLab. If not, see . * * The LRU cache is based on an idea by Robert Rossney see * . */ #endregion using System; using System.Collections.Generic; using System.Globalization; using System.IO; using System.Linq; using System.Text.RegularExpressions; using System.Threading; using HeuristicLab.Common; using HeuristicLab.Common.Resources; using HeuristicLab.Core; using HeuristicLab.Data; using HeuristicLab.Parameters; using HeuristicLab.Persistence.Default.CompositeSerializers.Storable; namespace HeuristicLab.Problems.ExternalEvaluation { [Item("EvaluationCache", "Cache for external evaluation values")] [StorableClass] public class EvaluationCache : ParameterizedNamedItem { #region Types private sealed class CacheEntry { public readonly string Key; public double Value; public CacheEntry(string key, double value) { Key = key; Value = value; } public CacheEntry(string key) { Key = key; } public override bool Equals(object obj) { CacheEntry other = obj as CacheEntry; if (other == null) return false; return Key.Equals(other.Key); } public override int GetHashCode() { return Key.GetHashCode(); } public override string ToString() { return string.Format("{{{0} : {1}}}", Key, Value); } } public delegate double Evaluator(SolutionMessage message); #endregion #region Fields private LinkedList list; private Dictionary> index; private HashSet activeEvaluations = new HashSet(); private object cacheLock = new object(); #endregion #region Properties public static new System.Drawing.Image StaticItemImage { get { return VSImageLibrary.Database; } } public int Size { get { lock (cacheLock) return index.Count; } } public int ActiveEvaluations { get { lock (cacheLock) return activeEvaluations.Count; } } [Storable] public int Hits { get; private set; } #endregion #region events public event EventHandler Changed; protected virtual void OnChanged() { EventHandler handler = Changed; if (handler != null) handler(this, EventArgs.Empty); } #endregion #region Parameters public FixedValueParameter CapacityParameter { get { return (FixedValueParameter)Parameters["Capacity"]; } } public FixedValueParameter PersistentCacheParameter { get { return (FixedValueParameter)Parameters["PersistentCache"]; } } #endregion #region Parameter Values public int Capacity { get { return CapacityParameter.Value.Value; } set { CapacityParameter.Value.Value = value; } } public bool IsPersistent { get { return PersistentCacheParameter.Value.Value; } } #endregion #region Persistence [Storable(Name = "Cache")] private IEnumerable> Cache_Persistence { get { if (IsPersistent) { return GetCacheValues(); } else { return Enumerable.Empty>(); } } set { SetCacheValues(value); } } [StorableHook(HookType.AfterDeserialization)] private void AfterDeserialization() { RegisterEvents(); } #endregion #region Construction & Cloning [StorableConstructor] protected EvaluationCache(bool deserializing) : base(deserializing) { } protected EvaluationCache(EvaluationCache original, Cloner cloner) : base(original, cloner) { SetCacheValues(original.GetCacheValues()); Hits = original.Hits; RegisterEvents(); } public EvaluationCache() { list = new LinkedList(); index = new Dictionary>(); Parameters.Add(new FixedValueParameter("Capacity", "Maximum number of cache entries.", new IntValue(10000))); Parameters.Add(new FixedValueParameter("PersistentCache", "Save cache when serializing object graph?", new BoolValue(false))); RegisterEvents(); } public override IDeepCloneable Clone(Cloner cloner) { return new EvaluationCache(this, cloner); } #endregion #region Event Handling private void RegisterEvents() { CapacityParameter.Value.ValueChanged += new EventHandler(CapacityChanged); } void CapacityChanged(object sender, EventArgs e) { if (Capacity < 0) throw new ArgumentOutOfRangeException("Cache capacity cannot be less than zero"); lock (cacheLock) Trim(); OnChanged(); } #endregion #region Methods public void Reset() { lock (cacheLock) { list = new LinkedList(); index = new Dictionary>(); Hits = 0; } OnChanged(); } public double GetValue(SolutionMessage message, Evaluator evaluate) { var entry = new CacheEntry(message.ToString()); bool lockTaken = false; bool waited = false; try { Monitor.Enter(cacheLock, ref lockTaken); while (true) { LinkedListNode node; if (index.TryGetValue(entry, out node)) { list.Remove(node); list.AddLast(node); Hits++; lockTaken = false; Monitor.Exit(cacheLock); OnChanged(); return node.Value.Value; } else { if (!waited && activeEvaluations.Contains(entry.Key)) { while (activeEvaluations.Contains(entry.Key)) Monitor.Wait(cacheLock); waited = true; } else { activeEvaluations.Add(entry.Key); lockTaken = false; Monitor.Exit(cacheLock); OnChanged(); try { entry.Value = evaluate(message); Monitor.Enter(cacheLock, ref lockTaken); index[entry] = list.AddLast(entry); Trim(); } finally { if (!lockTaken) Monitor.Enter(cacheLock, ref lockTaken); activeEvaluations.Remove(entry.Key); Monitor.PulseAll(cacheLock); lockTaken = false; Monitor.Exit(cacheLock); } OnChanged(); return entry.Value; } } } } finally { if (lockTaken) Monitor.Exit(cacheLock); } } private void Trim() { while (list.Count > Capacity) { var item = list.First; list.Remove(item); index.Remove(item.Value); } } private IEnumerable> GetCacheValues() { lock (cacheLock) { return index.ToDictionary(kvp => kvp.Key.Key, kvp => kvp.Key.Value); } } private void SetCacheValues(IEnumerable> value) { lock (cacheLock) { list = new LinkedList(); index = new Dictionary>(); foreach (var kvp in value) { var entry = new CacheEntry(kvp.Key) { Value = kvp.Value }; index[entry] = list.AddLast(entry); } } } public void Save(string filename) { using (var writer = new StreamWriter(filename)) { lock (cacheLock) { foreach (var entry in list) { writer.WriteLine(string.Format(CultureInfo.InvariantCulture, "\"{0}\", {1}", Regex.Replace(entry.Key, "\\s", "").Replace("\"", "\"\""), entry.Value)); } } writer.Close(); } } #endregion } }