source: trunk/sources/HeuristicLab.Core/PersistenceManager.cs @ 21

Last change on this file since 21 was 21, checked in by abeham, 13 years ago

Before saving to a file, a check is made if the file exists in which case it is overwritten with an empty string
fixes bug #25

File size: 3.4 KB
Line 
1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2008 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Collections.Generic;
24using System.Text;
25using System.Xml;
26using System.IO;
27
28namespace HeuristicLab.Core {
29  public static class PersistenceManager {
30    public static XmlDocument CreateXmlDocument() {
31      XmlDocument document = new XmlDocument();
32      document.AppendChild(document.CreateXmlDeclaration("1.0", null, null));
33      return document;
34    }
35    public static XmlNode Persist(IStorable instance, XmlDocument document, IDictionary<Guid, IStorable> persistedObjects) {
36      return Persist(instance.GetType().Name, instance, document, persistedObjects);
37    }
38    public static XmlNode Persist(string name, IStorable instance, XmlDocument document, IDictionary<Guid, IStorable> persistedObjects) {
39      if (persistedObjects.ContainsKey(instance.Guid)) {
40        XmlNode node = document.CreateNode(XmlNodeType.Element, name, null);
41        XmlAttribute guidAttribute = document.CreateAttribute("GUID");
42        guidAttribute.Value = instance.Guid.ToString();
43        node.Attributes.Append(guidAttribute);
44        return node;
45      } else {
46        persistedObjects.Add(instance.Guid, instance);
47        XmlNode node = instance.GetXmlNode(name, document, persistedObjects);
48        return node;
49      }
50    }
51    public static IStorable Restore(XmlNode node, IDictionary<Guid,IStorable> restoredObjects) {
52      Guid guid = new Guid(node.Attributes["GUID"].Value);
53      if (restoredObjects.ContainsKey(guid)) {
54        return restoredObjects[guid];
55      } else {
56        Type type = Type.GetType(node.Attributes["Type"].Value, true);
57        IStorable instance = (IStorable)Activator.CreateInstance(type);
58        restoredObjects.Add(guid, instance);
59        instance.Populate(node, restoredObjects);
60        return instance;
61      }
62    }
63    public static void Save(IStorable instance, string filename) {
64      if (File.Exists(filename)) File.WriteAllText(filename, "");
65      Save(instance, File.OpenWrite(filename));
66    }
67    public static void Save(IStorable instance, Stream stream) {
68      XmlDocument document = PersistenceManager.CreateXmlDocument();
69      document.AppendChild(Persist(instance, document, new Dictionary<Guid, IStorable>()));
70      document.Save(stream);
71    }
72    public static IStorable Load(string filename) {
73      return Load(File.OpenRead(filename));
74    }
75    public static IStorable Load(Stream stream) {
76      XmlDocument doc = new XmlDocument();
77      doc.Load(stream);
78      return PersistenceManager.Restore(doc.ChildNodes[1], new Dictionary<Guid, IStorable>());
79    }
80  }
81}
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