C# Wie man eine ConcurrentQueue so macht, dass sie durch die Bedingung bereinigt wird

Question

Wie man eine ConcurrentQueue bereinigt, die von der Bedingung für die ersten Elemente bereinigt wird. ZB um ältere Blogposts zu löschen. Ich kam mit dieser Idee einer ConditionConcurrentQueue up:

using System; 
using System.Collections.Generic; 
using System.Collections.Concurrent; 
using System.Threading; 

public class ConditionConcurrentQueue<T> : ConcurrentQueue<T> 
    where T: class 
{ 
    public ConditionConcurrentQueue(Func<T, bool> condition) 
     : this(null, condition) 
    { } 

    public ConditionConcurrentQueue(IEnumerable<T> items, Func<T, bool> condition) 
     : base(items) 
    { 
     _condition = condition; 
    } 

    private Func<T, bool> _condition; 

    public virtual void Enqueue(T item) 
    { 
     T removed; 
     bool cleaningRun = true; 
     int failedCnt = 0; 

     while (!IsEmpty && cleaningRun && failedCnt < 10) 
     { 
      if (TryPeek(out removed)) 
      { 
       bool result = _condition.Invoke(removed); 

       if (!result) 
       { 
        if (!TryDequeue(out removed)) 
        { 
         failedCnt++; 
         Thread.Sleep(10); 
        } 
       } 
       else 
        cleaningRun = false; 
      } 
      else 
      { 
       failedCnt++; 
       Thread.Sleep(10); 
      } 
     } 

     base.Enqueue(item); 
    } 
} 

verwenden ConditionConcurrentQueue könnte so:

class Blog 
{ 
    public ConditionConcurrentQueue<Post> Posts { get; set; } 
} 

class Post 
{ 
    public DateTime Time { get; set; } 

    public string Text { get; set; } 
} 

class Program 
{ 
    static void Main(string[] args) 
    { 
     Blog blog = new Blog 
     { 
      Posts = new ConditionConcurrentQueue<Post>(
      new Post[] { 
         new Post { Time = DateTime.Now - TimeSpan.FromMinutes(80), Text = "Title 1" }, 
         new Post { Time = DateTime.Now - TimeSpan.FromMinutes(60), Text = "Title 2" }, 
         new Post { Time = DateTime.Now - TimeSpan.FromMinutes(40), Text = "Title 3" }, 
         }, 
      p => p.Time > DateTime.Now - TimeSpan.FromHours(1)) 
     }; 

     blog.Posts.Enqueue(new Post { Time = DateTime.Now - TimeSpan.FromMinutes(20), Text = "Title 4" }); 

     foreach (Post post in blog.Posts.ToList()) 
      Console.WriteLine(post.Text); 
    } 
} 

vielleicht ist es zu primitiv Lösung. Ich würde alle Verbesserungen schätzen. Vielen Dank.

Answer 1

auch, können Sie durch die Erweiterung Methode versuchen:

public static ICollection<T> Enqueue<T>(this ConcurrentQueue<T> field, T item, Func<T, bool> predicate) 
    { 
     ICollection<T> removed = field.TryDequeue<T>(predicate); 

     field.Enqueue(item); 

     return removed; 
    } 

    public static ICollection<T> TryDequeue<T>(this ConcurrentQueue<T> field, Func<T, bool> predicate) 
    { 
     T comparedItem; 
     var removedList = new List<T>(); 

     while (field.TryPeek(out comparedItem)) 
     { 
      if (!predicate.Invoke(comparedItem)) 
      { 
       if (field.TryDequeue(out comparedItem)) 
        removedList.Add(comparedItem); 
       else 
        break; 
      } 
      else 
       break; 
     } 

     return removedList; 
    }