public static void WriteTokens(TokenMachine tokenMachine, Memento memento)
{
Console.WriteLine("Token machine:");
WriteTokens(tokenMachine);
Console.WriteLine("Memento:");
WriteTokens(memento);
}
public static void WriteTokens(TokenMachine tokenMachine)
{
var tokens = tokenMachine.Tokens;
for (int i = 0; i < tokens.Count; i++)
{
Console.WriteLine($"{i}) {tokens[i]}");
}
}
public void SingleTokenTest()
{
var tm = new TokenMachine();
var m = tm.AddToken(123);
tm.AddToken(456);
tm.Revert(m);
Assert.That(tm.Tokens.Count, Is.EqualTo(1));
Assert.That(tm.Tokens[0].Value, Is.EqualTo(123));
}
static void Main(string[] args)
{
/*
* This is a trivial example of implementing memento pattern.
* In this example our bank account methods return a snapshot of it's balance
* after the operation so that we can save those tokens and restore our account
* to any state later.
*/
var ba = new SimpleBankAccount(100);
var s1 = ba.Deposit(50); // 150
var s2 = ba.Deposit(100); // 250
WriteLine(ba);
ba.Restore(s1);
WriteLine(ba);
ba.Restore(s2);
WriteLine(ba);
/*
* This example illustrates a more advanced example of memento pattern
* as a form of undo and redo implementation.
*/
var b = new BankAccount(100);
b.Deposit(50);
var as1 = b.Deposit(25);
WriteLine(b);
b.Undo();
WriteLine($"Undo 1 {b}");
b.Undo();
WriteLine($"Undo 2 {b}");
b.Redo();
WriteLine($"Redo {b}");
b.Restore(as1);
WriteLine($"Restore {b}");
var tm = new TokenMachine();
var testToken = new Token(1);
var h1 = tm.AddToken(testToken); // 1
var h2 = tm.AddToken(new Token(3)); // 1, 3
var h3 = tm.AddToken(new Token(5)); // 1,3,5
WriteLine(tm);
testToken.Value = 10;
WriteLine(tm); // 10,3,5
tm.Revert(h2);
WriteLine(tm); // 1, 3
}
static void Main(string[] args)
{
var tm = new TokenMachine();
var t = new Token(111);
var m = tm.AddToken(t);
WriteTokens(tm, m);
t.Value = 333;
WriteTokens(tm, m);
}
public void TwoTokenTest()
{
var tm = new TokenMachine();
tm.AddToken(1);
var m = tm.AddToken(2);
tm.AddToken(3);
tm.Revert(m);
Assert.That(tm.Tokens.Count, Is.EqualTo(2));
Assert.That(tm.Tokens[0].Value, Is.EqualTo(1),
$"First token should have value 1, you got {tm.Tokens[0].Value}");
Assert.That(tm.Tokens[1].Value, Is.EqualTo(2));
}
public void FiddledTokenTest()
{
var tm = new TokenMachine();
Console.WriteLine("Made a token with value 111 and kept a reference");
var token = new Token(111);
Console.WriteLine("Added this token to the list");
tm.AddToken(token);
var m = tm.AddToken(222);
Console.WriteLine("Changed this token's value to 333 :)");
token.Value = 333;
tm.Revert(m);
Assert.That(tm.Tokens.Count, Is.EqualTo(2),
$"At this point, token machine should have exactly two tokens, you got {tm.Tokens.Count}");
Assert.That(tm.Tokens[0].Value, Is.EqualTo(111),
$"You got the token value wrong here. Hint: did you init the memento by value?");
}