public interface ILinkableComponent
  {
      LinkableComponentStatus Status { get; }
            
      void Initialize();

      void Validate();

      void Update();

      void Finish();
              
      IList<IInputItem> InputItems { get; }
              
      IList<IOutputItem> OutputItems { get; }
      
      IList<IOutputDecorator> OutputDecorators { get; }

      // (another discussion) filtered data
      // get's values from the specified component
      IMatrix GetValues(IInputExchangeItem query);
      
      //    
      // when this property is set to true
      //
      // default value is false (allow cascade calls, pull-driven)
      //
      bool CascadeUpdateCallsDisabled { get; set; }        
  }

  public interface IInputItem : IExchangeItem
  {
      IMatrix Values { get; set; }
  }
    
  public interface IOutputItem : IExchangeItem
  {
      IMatrix Values { get; }
  }

  // =================================== pull approach
  
  var triggerExchangeItem = component.OutputItems[0];
  
  triggerComponent.GetValues(triggerExchangeItem);


  // =================================== loop approach
  
  while(!allComponentsAreFinished)
  {
      foreach(var component in components)
      {
          if(component.Status != LinkableComponentStatus.Finished)
          {
              component.Update();
          }
      }
  }  

  // current
  public interface IMatrix : IList
  {
      int Rows { get; }
      
      int Columns { get; }

      object GetValue(int row, int column);

      void SetValue(object value, int row, int column);
      
      object[,] GetValues(int startRow, int endRow, int startColumn, int endColumn);

      void SetValues(object[,] values, int startRow, int endRow, int startColumn, int endColumn);
  }