anupavanm / csharp-design-patterns-for-humans Goto Github PK

Hi
last line of code in Prototype should print Jolly which is original.Name instead of Dolly

The provided example for Singleton design pattern is not thread safe. This is the most basic implementation of the Singleton pattern. Please add the thread safe, lazy implementation.

public sealed class Singleton
{
    private static readonly Lazy<Singleton> lazy =
        new Lazy<Singleton>(() => new Singleton());
    
    public static Singleton Instance { get { return lazy.Value; } }

    private Singleton()
    {
    }
}

Below article from Jon Skeet would be helpful
http://csharpindepth.com/Articles/General/Singleton.aspx

Strategy using example:

var sorter = new Sorter(new QuickSortStrategy());
sorter.Sort(unSortedList); // // Output : Sorting using Bubble Sort !

QuickSortStrategy - > BubbleSortStrategy

For iterator pattern should be:

public IEnumerator<RadioStation> GetEnumerator()
{
            //Use can switch to this internal collection if you do not want to transform
            //return mStations.GetEnumerator();

            //use this if you want to transform the object before rendering
            foreach (var x in mStations)
            {
                yield return x;
            }
 }

IEnumerator IEnumerable.GetEnumerator()
{
            return this.GetEnumerator();
}

Currently is wrong and throws StackOverflowException.

public IEnumerator<RadioStation> GetEnumerator()
 {
            return this.GetEnumerator();
 }

 IEnumerator IEnumerable.GetEnumerator()
 {
            //Use can switch to this internal collection if you do not want to transform
            //return mStations.GetEnumerator();

            //use this if you want to transform the object before rendering
            foreach (var x in Stations)
            {
            yield return x;
            }
}

Before the Simple Factory, is this text:

The basic form of object creation could result in design problems or added complexity to the design. Creational design patterns solve this problem by somehow controlling this object creation.

While the individual subjects have some brief statement, sometimes these seem not to be either problems or (at least unreasonable) complexities. In fact, the "Door" example doesn't even present the situation that is covered in the "When to use" section of the Simple Factory description.

Suggestion: Give an example, in every one of these, of a common situation that would in fact have more problems/design issues, before presenting a solution to it.

At the Singleton example, get_instance() should be GetInstance().
Also there is a redundant call to .ToString().