blog.darkstar.work - a simple url encoder/decoder

 a simple url encoder/decoder
 http://blog.darkstar.work

Labels

Wirtschaft (148) Österreich (119) Pressefreiheit (118) IT (91) code (56) Staatsschulden (37) EZB (27) Pensionssystem (15)

2022-05-08

A crazy example of a Lazy singleton as strangest singelton pattern ever

A crazy example of a Lazy<T> singelton with privat constructor inherited form an protected DoubleLockInstance singelton with private empty and protected parameter constructor inherited form an abstract singelton template with protected constructor.


Application settings example:


BaseSets for basic settings as abstract singelton base


using System;using System.Reflection;
namespace work.darkstar.blog{    /// <summary>    /// abstract class BaseSets     /// </summary>    [Serializable]    public abstract class BaseSets    {        public string AssemblyName { get => Assembly.GetExecutingAssembly().GetName().ToString(); }        public string Copyright { get => "GNU LIGHT GENERAL PUBLIC LICENSE 2.0 LGPL"; }        public virtual string AssemblyCom { get => "darkstar.work"; }
        public virtual int AppId { get; protected set; }        public virtual string AppName { get; protected set; }        /// <summary>        /// protected empty constructor for inheritable singelton        /// </summary>        protected BaseSets() { }         /// <summary>        /// protected parameterized constructor for inheritable singelton        /// </summary>        protected BaseSets(int appId, string appName)        {            AppId = appId;  AppName = appName;        }    }}

AppSets for application settings as instancable singelton default app sets (settings):

using Microsoft.Win32;
using System;
using System.Reflection;
using System.Windows.Forms;

namespace work.darkstar.blog
{
    public interface IAppSetsDomain : IAppDomainSetup    {        System.AppDomain AppCurrentDomain { get; }    }    /// <summary>
    /// application settings singelton    /// </summary>
    [Serializable]    public class AppSets : BaseSets, IAppDomainSetup
    {
        
private static AppSets _appSets;
        private static object  _initLock, _sndLock;
        protected static AppSets DoubleLockInstance {            get {                _sndLock = new System.Object();                lock (_sndLock)  {                    if (_initLock != null) _initLock = null;
                    if (_initLock == null) _initLock = new System.Object();                    lock (_initLock) {                       if (_appSets == null)                            _appSets = new AppSets();                    }                    return _appSets;                }            }        }        public string CodeBase { get => Assembly.GetExecutingAssembly().CodeBase; }
        public string BaseDirectory { get => AppDomain.CurrentDomain.BaseDirectory; }        public string AppDataPath { get => Application.CommonAppDataPath; }        public RegistryKey AppDataRegistry { get => Application.CommonAppDataRegistry; }

        #region implementing interface IAppSetsDomain, IAppDomainSetup        
        public AppDomain AppCurrentDomain { get => AppDomain.CurrentDomain; }
        public string ApplicationBase get set; }
        public string ApplicationNameget set; }
        public string CachePathget set; }
        public string ConfigurationFileget set; }
        public string DynamicBase get set; }
        public string LicenseFile get set; }
        public string PrivateBinPath get set; }
        public string PrivateBinPathProbe get set; }
        public string ShadowCopyDirectories get set; }
        public string [] ShadowCopyDirectoryArray { 
                get => ShadowCopyDirectories.Split(';'); }
        public bool FilesShadowCopy { get set; }
        public string ShadowCopyFiles { 
            get => FilesShadowCopy.ToString().ToLower();
            set { FilesShadowCopy = Boolean.Parse(value); }
        }
        public bool FilesShadowCopyget set; }
        public string ShadowCopyFilesget => FilesShadowCopy.ToString() set; }
        #endregion implementing interface IAppSetsDomain, IAppDomainSetup        

        /// <summary>        /// static constructor         /// </summary>        static AppSets() {
            
_initLock = new System.Object();
            
lock (_initLock) { _appSets = new AppSets(); }
        }
        /// <summary>        /// private empty constructor         /// </summary>        private AppSets() {            AppId = AppDomain.CurrentDomain.Id;            AppName = Assembly.GetExecutingAssembly().FullName;                      }
        /// <summary>        /// protected parameter constructor         /// </summary>        protected AppSets(int appId, string appName) : base(appId, appName) { }
    }}

Sealed MyAppSets for application specialized appSets as Lazy<T> singelton:

using System;
using System.IO; using System.Security;
/* ... */using Microsoft.Win32;/* ... */using Windows.Forms; namespace work.darkstar.blog { /// <summary> /// my application settings singelton /// </summary> [Serializable] public sealed class MyAppSets : AppSets { /// <summary> /// private static readonly Lazy<T> self containing private real singelton unique instance /// </summary> private static readonly Lazy<MyAppSets> _instance = new Lazy<MyAppSets>(() => new MyAppSets(AppDomain.CurrentDomain.Id, "LazyApp")); /// <summary> /// static instance getter for Singeltion /// </summary> public static MyAppSets Instance { get => _instance.Value; } public string UserAppDataPath { get => Application.UserAppDataPath; } public RegistryKey UserAppDataRegistry { get => Application.UserAppDataRegistry; } /// <summary> /// private constructor with partameters for sealed unique singelton /// </summary> private MyAppSets(int appId, string appName) : base(appId, appName) { } /// <summary> /// Gets name value pair for application registry key saved in registry scope for current user /// </summary> /// <param name="regName">registry name identifier</param> /// <param name="subKey">subKey in scope of current user</param> /// <returns>object value</returns> /// <exception cref="ApplicationException">application exception with detailed inner exception</exception> public object GetUserRegValuey(string regName, string subKey = null) { object o = null; RegistryKey key = null; Exception ex = null; try { key = (subKey == null) ? UserAppDataRegistry : UserAppDataRegistry.OpenSubKey(subKey, false); o = key.GetValue(regName); } catch (SecurityException sex) { ex = sex; } catch (ObjectDisposedException odEx) { ex = odEx; } catch (UnauthorizedAccessException uaEx) { ex = uaEx; } catch (IOException ioeEx) { ex = ioeEx; } finally { if (key != null && subKey != null) key.Close(); if (ex != null) throw (new ApplicationException("Error accessing registy key: " + $"{UserAppDataRegistry}\t name: {regName}\t subkey: {subKey}", ex)); } return o; } /// <summary> /// Set Value for UserAppDataRegistry /// </summary> /// <param name="regName">registry name </param> /// <param name="value"value to set></param> /// <param name="subKey">subKey</param> /// <returns>void means nothing</returns> /// <exception cref="ApplicationException">application exception with detailed inner exception</exception> public void SetUserReg(string regName, object value, string subKey = null) { RegistryKey key = null; Exception ex = null; try { key = (subKey == null) ? UserAppDataRegistry : UserAppDataRegistry.OpenSubKey(subKey, true); key.SetValue(regName, value); } catch (Exception anyEx) { ex = new ApplicationException($"Error setting value=" + $"{value} for name={regName} inside registry key: {key.Name}", anyEx); } finally { if (key != null && subKey != null) key.Close(); if (ex != null) throw ex; } } } }

Accessing MyAppSets singelton inside any entity, framework,  helper, [...] class


using System; /*  ... */
using work.darkstar.blog;

public class MyEntity : IAppSetsDomain {
  /* [ ... ] */
  /* [Inject] */
  /* [ ... ] */

  public AppDomain AppCurrentDomain {
    get => MyAppSets.Instance.AppCurrentDomain;     set => MyAppSets.Instance.AppCurrentDomain = value;   }   /* ... */ }