{/// <summary>
/// An Example of using the State Pattern
/// The state pattern is good for managing linear processes, but I find it can get very complicated very quickly.
/// It allows you to call a method of a class to do something, but you are only allowed to do that thing if all the
/// pre-requisites steps have been successfully completed.
/// in the past, I have used shift registers to move tokens up and down, but this is a nice and clever OOP way
/// This example is about a box of things that have been ordered.
/// The box can have a number of states, each state is an individual class which each class implements the IBoxState
/// The IBoxState defines ALL the methods the system needs to be able to move from one state to another
/// e.g. AcceptBox(). Openbox(), RemoveContents() and GetRidOfBox(). this meach each state class has those methods
/// We can put the code in these methods to reflect what each method can do in that particular state
/// So If the state of the box is Undelivered, its openBox(), RemoveContents() and GetRidOfBox() dont do anything
/// because before we can open the box, it must be delivered.
///
/// We then create a context class that also implements IBoxState, meaning the context class has all the same methods.
/// The context class also has a local copy of IBoxState which we point to the current state of the object.
/// So on statrt up, we set the local copy of IBoxState to BoxUndeliveredState.
/// Then on each method, we intercept the normal Context class codes mthods, and tell them to execute the same method
/// within the current local IBoxState. Take a look at the methods in the context class and it will make sense.
/// </summary>
/// <param name="args"></param>
static void Main(string[] args)
{
// States
// create my context class
BoxContext myBox = new BoxContext();
// run through each step in order, the methods alter the state of the context box
Console.WriteLine("box 1\n");
myBox.AcceptBox();
//myBox.ReturnBox();
myBox.OpenBox();
myBox.EmptyBox();
myBox.ThrowAwayBox();
// run through again,we try to open the box after it has been returned and the code refuses to allow us to do that.
Console.WriteLine("\nbox 2");
myBox.AcceptBox();
myBox.ReturnBox();
myBox.OpenBox();
myBox.EmptyBox();
myBox.ThrowAwayBox();
Console.WriteLine("\nbox 3");
myBox.EmptyBox();
}
private async Task<BoxContext> RequireContext(RootName root, string apiKey = null)
{
if (root == null)
throw new ArgumentNullException(nameof(root));
var result = default(BoxContext);
if (!contextCache.TryGetValue(root, out result)) {
var client = await OAuthAuthenticator.Login(root.UserName, apiKey);
contextCache.Add(root, result = new BoxContext(client));
}
return result;
}
private async Task <BoxContext> RequireContextAsync(RootName root, string apiKey = null)
{
if (root == null)
{
throw new ArgumentNullException(nameof(root));
}
if (!contextCache.TryGetValue(root, out BoxContext result))
{
var client = await OAuthAuthenticator.LoginAsync(root.UserName, apiKey, settingsPassPhrase);
contextCache.Add(root, result = new BoxContext(client));
}
return(result);
}
public BoxesController(BoxContext context)
{
_context = context;
}
