Design patterns you didn't know about
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- 3. //Initialize customer andinvoice Initialize(customer, invoice);
- 4. public void Initialize (Customercustomer, Invoice invoice) { customer.Name = “asdf”; invoice.Date = DateTime.Now; }
- 5. Initialize(customer, invoice); //did somethinghappen to customer // and/or invoice?
- 6. customer.Name = InitNameFrom(customer, invoice); invoice.Date= InitDateFrom(customer, invoice);
- 7. customer.Name = GetNameFrom(customer, invoice); invoice.Date= GetDateFrom(customer, invoice);
- 8. var results = Initialize(customer,invoice); customer.Name = results.Item1; invoice.Date = results.Item2;
- 9. public tuple<string, DateTime> Initialize(customer,invoice) { return new Tuple<string, DateTime> (“asdf”, DateTime.Now); }
- 10. tuple •Avoid side effects •Avoidout parameters •multiple values without a specific type
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- 12. private ILogger _logger; publicMyClass(ILogger logger) { _logger = logger; } … if (_logger != null) { _logger.Debug( “it worked on my machine!”); }
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- 15. public class NullLogger: ILogger { public void Debug(string text) { //do sweet nothing } }
- 16. private ILogger _logger= new NullLogger(); public MyClass(ILogger logger) { _logger = logger; } … _logger.Debug( “it worked on my machine!”);
- 17. null object •Can eliminatenull checks •Simple to implement
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- 24. Limit the # ofretries
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- 31. On Off whennot healthy
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- 33. Get to software beforewe cut you
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- 39. Your Application External Dependency Circuit Breaker Threshold = 2 Pause= 10ms Timeout = 30s State = Closed Request Request Failure (i.e. HTTP 500) Failure Count = 1 Pause 10ms Request Failure (i.e. HTTP 500) Failure Count = 2 State = Open OperationFailedException
- 40. Your Application External Dependency Circuit Breaker Threshold = 2 Pause= 10ms Timeout = 30s State = Open Request 30s has not passed CircuitBreakerOpenException Request 30s has not passed CircuitBreakerOpenException System can try to become healthy for 30s
- 41. Your Application External Dependency Circuit Breaker Threshold = 2 Pause= 10ms Timeout = 30s State = ½ Open Request Request Failure (i.e. HTTP 500) Failure Count = 2 State = Open OperationFailedException 30s has passed
- 42. Your Application External Dependency Circuit Breaker Threshold = 2 Pause= 10ms Timeout = 30s State = ½ Open Request Request Failure Count = 0 State = Closed Response 30s has passed Response
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- 44. ½ Open is likea manual reset
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- 53. Your Application External Dependency Circuit Breaker Threshold = 3 State= Closed Request Request Failure (i.e. HTTP 500) Failure Count = 1 Request Failure (i.e. HTTP 500) Failure Count = 2 Failure Count = 0 State = Closed Response Response Request ?
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- 61. circuit breaker •retry looping •slowdown attempts •good neighbour