Org.Lwes/DB/EventTemplateDB.cs

   1 //
   2 // This file is part of the LWES .NET Binding (LWES.net)
   3 //
   4 // COPYRIGHT© 2009, Phillip Clark (phillip[at*flitbit[dot*org)
   5 //       original .NET implementation
   6 //
   7 // LWES.net is free software: you can redistribute it and/or modify
   8 // it under the terms of the Lesser 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 // LWES.net 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 // Lesser GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the Lesser GNU General Public License
  18 // along with LWES.net.  If not, see <http://www.gnu.org/licenses/>.
  19 //
  20 namespace Org.Lwes.DB
  21 {
  22         using System;
  23
  24         using Org.Lwes.Config;
  25
  26         /// <summary>
  27         /// Utility class for accessing the default IEventTemplateDB implementation.
  28         /// </summary>
  29         /// <remarks>
  30         /// <para>If there is an ambient ServiceLocator present then this utility class will
  31         /// delegate to the ServiceLocator. The ServiceLocator should declare an instance
  32         /// of IEventTemplateDB with the name "eventTemplateDB".</para>
  33         /// <para>If an IoC container is not present, or if a service instance is not defined
  34         /// with the name "eventTemplateDB" then this utility will create a FilePathEventTemplateDB
  35         /// initialized to use the application's base directory to load event specification files (*.esf) files.</para>
  36         /// </remarks>
  37         public static class EventTemplateDB
  38         {
  39                 #region Methods
  40
  41                 /// <summary>
  42                 /// Accesses the default instance of the IEventTemplateDB. Delegates to
  43                 /// an IoC container if present.
  44                 /// </summary>
  45                 public static IEventTemplateDB CreateDefault()
  46                 {
  47                         IEventTemplateDB result;
  48                         if (!IoCAdapter.TryCreateFromIoC<IEventTemplateDB>(Constants.DefaultEventTemplateDBContainerKey, out result))
  49                         { // Either there isn't a default event template defined in the IoC container
  50                                 // or there isn't an IoC container in use... fall back to configuration section.
  51                                 result = CreateFromConfig(Constants.DefaultEventTemplateDBConfigName);
  52                         }
  53                         if (result == null)
  54                         { // Not in IoC and not configured; fallback to programmatic default.
  55                                 result = CreateFallbackTemplateDB();
  56                         }
  57                         return result;
  58                 }
  59
  60                 /// <summary>
  61                 /// Creates an event template DB from the configuration.
  62                 /// </summary>
  63                 /// <param name="name">name of the instance to create</param>
  64                 /// <returns>the named instance if it exists within the configuration;
  65                 /// otherwise null</returns>
  66                 /// <remarks>Note that two subsequent calls to this method will return
  67                 /// two separate instances of the configured instance.</remarks>
  68                 public static IEventTemplateDB CreateFromConfig(string name)
  69                 {
  70                         LwesConfigurationSection config = LwesConfigurationSection.Current;
  71                         if (config.TemplateDBs == null) return null;
  72
  73                         TemplateDBConfigurationSection namedTemplateDBConfig = config.TemplateDBs[name];
  74                         if (namedTemplateDBConfig == null) return null;
  75
  76                         FilePathEventTemplateDB db = new FilePathEventTemplateDB();
  77                         db.InitializeFromFilePath(namedTemplateDBConfig.Path, namedTemplateDBConfig.IncludeSubdirectories);
  78                         return db;
  79                 }
  80
  81                 /// <summary>
  82                 /// Creates the named instance. If an IoC container is in use the IoC
  83                 /// container is consulted for the named instance first.
  84                 /// </summary>
  85                 /// <param name="name">name of the instance to create</param>
  86                 /// <returns>the named instance if it exists either within the IoC container
  87                 /// or the configuration; otherwise null</returns>
  88                 public static IEventTemplateDB CreateNamedTemplateDB(string name)
  89                 {
  90                         IEventTemplateDB result;
  91                         if (!IoCAdapter.TryCreateFromIoC<IEventTemplateDB>(name, out result))
  92                         {
  93                                 result = CreateFromConfig(name);
  94                         }
  95                         return result;
  96                 }
  97
  98                 private static IEventTemplateDB CreateFallbackTemplateDB()
  99                 {
 100                         FilePathEventTemplateDB db = new FilePathEventTemplateDB();
 101                         db.InitializeFromFilePath(AppDomain.CurrentDomain.SetupInformation.ApplicationBase, true);
 102                         return db;
 103                 }
 104
 105                 #endregion Methods
 106         }
 107 }