Feature Parity in 25% of the Dev Hours with Technical Practices for Sustainable Code @TheQuinnGil QuinnGil.com

Feature Parity in 25% of the Dev Hours @TheQuinnGil QuinnGil.com

@TheQuinnGil QuinnGil.com Technical Practices for Sustainable Code

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Sustainable Code through Technical Practices @TheQuinnGil QuinnGil.com

Sustainable Code through Technical Practices @TheQuinnGil QuinnGil.com

Sustainable Code through Technical Practices @TheQuinnGil QuinnGil.com

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Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection @TheQuinnGil QuinnGil.com

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection No Getters / No Setters @TheQuinnGil QuinnGil.com

Technical Practices - No Getters / No Setters class FizzBuzzBag { public int Input { get; set; } public string Result { get; set; } } class FizzBuzzBag: def __init__(self): self._result = None self._input = None @property def result(self): return self._result @result.setter def result(self, value): self._result = value @property def input(self): return self._input @input.setter def input(self, value): self._input = value class FizzBuzzBag{ private int input; private String result; public String getResult(){ return result; } public void setResult(String value){ result = value; } public int getInput(){ return input; } public void setInput(int value){ input = value; } } class FizzBuzzBag attr_accessor :input attr_accessor :result end

Technical Practices - No Getters / No Setters No Way

No Getters / No Setters Technical Practices

Technical Practices - No Getters Why No Getters?

Technical Practices - No Setters Why No Setters?

Technical Practices - No Getters / No Setters How?

No Getters / No Setters - How? The Class Does It

Technical Practices - No Getters / No Setters public class FizzBuzz{ public int Input { get; set; } public string Result { get; set; } } public static class FizzBuzzUtils{ public static void Calculate(FizzBuzz fb){ if (fb.Input % 3 == 0){ fb.Result = "Fizz"; } if (fb.Input % 5 == 0){ if (fb.Result == null){ fb.Result = "Buzz"; } else { fb.Result += "Buzz"; } } if (string.IsNullOrEmpty(fb.Result)){ fb.Result = fb.Input.ToString(); } } }

Technical Practices - No Getters / No Setters public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } } public class FizzBuzz{ public int Input { get; set; } public string Result { get; set; } } public static class FizzBuzzUtils{ public static void Calculate(FizzBuzz fb){ if (fb.Input % 3 == 0){ fb.Result = "Fizz"; } if (fb.Input % 5 == 0){ if (fb.Result == null){ fb.Result = "Buzz"; } else { fb.Result += "Buzz"; } } if (string.IsNullOrEmpty(fb.Result)){ fb.Result = fb.Input.ToString(); } } }

Technical Practices - No Getters / No Setters Benefits

Sustainable Code through Technical Practices No Getters / No Setters @TheQuinnGil QuinnGil.com ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection `if` Only As Guard Clause @TheQuinnGil QuinnGil.com

Technical Practices - `if` Only As Guard Clause No Way

Technical Practices - `if` Only As Guard Clause Default Path

`if` Only As Guard Clause - Default Path public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } }

public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } } `if` Only As Guard Clause - Default Path public class FizzBuzz{ private int _input; public FizzBuzz(int input) => _input = input; public string Result(){ if (_input % 15 == 0) return "FizzBuzz"; if (_input % 3 == 0) return "Fizz"; if (_input % 5 == 0) return "Buzz"; return _input.ToString(); } }

Technical Practices - `if` Only As Guard Clause Cascading Changes

Technical Practices - `if` Only As Guard Clause Cascading Changes switch and else - always evil

Technical Practices - `if` Only As Guard Clause How?

`if` Only As Guard Clause - Default Path public class FizzBuzz{ private int _input; public FizzBuzz(int input) => _input = input; public string Result(){ if (_input % 15 == 0) return "FizzBuzz"; if (_input % 3 == 0) return "Fizz"; if (_input % 5 == 0) return "Buzz"; return _input.ToString(); } } public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ string result = null; if (_input % 3 == 0) result = "Fizz"; if (_input % 5 == 0){ if (result == null) result = "Buzz"; else result += "Buzz"; } if (string.IsNullOrEmpty(result)){ result = _input.ToString(); } return result; } }

Sustainable Code through Technical Practices `if` Only As Guard Clause @TheQuinnGil QuinnGil.com ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection Isolate Their Code @TheQuinnGil QuinnGil.com

Technical Practices - Isolate Their Code - 3rd Party public class FizzBuzz{ private readonly string _input; public FizzBuzz(string input) => _input = input; public string Result(){ JObject jObject = JObject.Parse(_input); int input = jObject.Value("number"); if (IsFizzBuzz(input)) return "FizzBuzz"; if (IsFizz(input)) return "Fizz"; if (IsBuzz(input)) return "Buzz"; return input.ToString(); } }

Technical Practices - Isolate Their Code - 3rd Party public class FizzBuzz{ private readonly string _input; private readonly IParser _parser; public string Result(){ IParsedObject pObject = _parser.Parse(_input); int input = pObject.IntValue("input"); if (IsFizzBuzz(input)) return "FizzBuzz"; if (IsFizz(input)) return "Fizz"; if (IsBuzz(input)) return "Buzz"; return input.ToString(); } }

What Else? Technical Practices - Isolate Their Code

Operating System Technical Practices - Isolate Their Code

How? Technical Practices - Isolate Their Code

Technical Practices - Isolate Their Code - How? internal class HttpClientBookEnd : IHttpClientBookEnd { private static HttpClient _testClient; #if DEBUG public static void SetTestClient(HttpClient testClient) => _testClient = testClient; #endif private readonly HttpClient _httpClient; public HttpClientBookEnd() : this(new HttpClient()) { } private HttpClientBookEnd(HttpClient httpClient) => _httpClient = httpClient; public void SendRequestAsync(HttpRequestMessage msg) => HttpClient().SendAsync(msg); private HttpClient HttpClient() => _testClient ?? _httpClient; }

User Interface Technical Practices - Isolate Their Code

Sustainable Code through Technical Practices Isolate Their Code @TheQuinnGil QuinnGil.com ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection Never `null` @TheQuinnGil QuinnGil.com

Why? Technical Practices - Never `null`

How? Technical Practices - Never `null`

Technical Practices - Never `null` public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; }

Technical Practices - Never `null` public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanBeNull canBeNull) { return canBeNull?.Example()?.Sample() ?? "Default"; }

Technical Practices - Never `null` public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanBeNull canBeNull) { return canBeNull?.Example()?.Sample() ?? "Default"; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); }

Technical Practices - Never `null` public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanBeNull canBeNull) { return canBeNull?.Example()?.Sample() ?? "Default"; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); } public void Foo() { string thing = _bar.CalculateThing(_canBeNull); //... }

Technical Practices - Never `null` public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public string CalculateThing(ICanBeNull canBeNull) { return canBeNull?.Example()?.Sample() ?? "Default"; } public string CalculateThing(ICanNotBeNull canNotBeNull) { return canNotBeNull.Example().Sample(); } public void Foo() { string thing = _bar.CalculateThing(_canBeNull); //... } public void Foo() { string thing = _canNotBeNull.Example().Sample(); //... }

Technical Practices - Never `null` public class NullObject : ICanNotBeNull { public IAlsoNotNull Example() => new NullObjectAlso(); } public class NullObjectAlso : IAlsoNotNull { public string Sample() => "Default"; } public string CalculateThing(ICanBeNull canBeNull) { if (canBeNull == null) return "Default"; IAlsoNull alsoNull = canBeNull.Example(); if (alsoNull == null) return "Default"; string sample = alsoNull.Sample(); if (sample == null) return "Default"; return sample; } public void Foo() { string thing = _canNotBeNull.Example().Sample(); //... }

Languages and Null

Sustainable Code through Technical Practices Never `null` @TheQuinnGil QuinnGil.com ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection No `new` inline @TheQuinnGil QuinnGil.com

Technical Practices - No `new` inline public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ if (new Mod15(_input).Remainder() == 0) return "FizzBuzz"; if (new Mod3(_input).Remainder() == 0) return "Fizz"; if (new Mod5(_input).Remainder() == 0) return "Buzz"; return _input.ToString(); } }

Technical Practices - No `new` inline public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ if (Mod15().Remainder() == 0) return "FizzBuzz"; if (Mod3().Remainder() == 0) return "Fizz"; if (Mod5().Remainder() == 0) return "Buzz"; return _input.ToString(); } private IRemainder Mod15() => new Mod15(_input); private IRemainder Mod3() => new Mod3(_input); private IRemainder Mod5() => new Mod5(_input); }

Technical Practices - No `new` inline public class FizzBuzz{ private readonly int _input; private readonly ModFactory factory; public FizzBuzz(int input) => _input = input; public string Result(){ if (factory.Mod15(_input).Remainder() == 0) return "FizzBuzz"; if (factory.Mod3(_input).Remainder() == 0) return "Fizz"; if (factory.Mod5(_input).Remainder() == 0) return "Buzz"; return _input.ToString(); } } public class ModFactory{ public IRemainder Mod15(int input) => new Mod15(input); public IRemainder Mod3(int input) => new Mod3(input); public IRemainder Mod5(int input) => new Mod5(input); }

Where DO we Create? Technical Practices

No `new` inline - Where DO We Create? public class FizzBuzz{ public string Result(){ IFizzBuzzInput input = new FizzBuzzInput(); if (input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (input.EvenlyDivisibleBy(3)) return "Fizz"; if (input.EvenlyDivisibleBy(5)) return "Buzz"; return input.ToString(); } }

No `new` inline - Where DO We Create? public class FizzBuzz{ private readonly IFizzBuzzInput _input; public FizzBuzz() : this(new FizzBuzzInput()) { } private FizzBuzz(IFizzBuzzInput fizzBuzzInput) => _input = fizzBuzzInput; public string Result(){ if (_input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (_input.EvenlyDivisibleBy(3)) return "Fizz"; if (_input.EvenlyDivisibleBy(5)) return "Buzz"; return _input.ToString(); } } public class FizzBuzz{ public string Result(){ IFizzBuzzInput input = new FizzBuzzInput(); if (input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (input.EvenlyDivisibleBy(3)) return "Fizz"; if (input.EvenlyDivisibleBy(5)) return "Buzz"; return input.ToString(); } }

No `new` inline - Where DO We Create? public class FizzBuzz{ private readonly IFizzBuzzService _service; public FizzBuzz() : this(new FizzBuzzService()) { } private FizzBuzz(IFizzBuzzService fizzBuzzService) => _service = fizzBuzzService; public string Result(){ IFizzBuzzInput input = _service.FizzBuzzInput(); if (input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (input.EvenlyDivisibleBy(3)) return "Fizz"; if (input.EvenlyDivisibleBy(5)) return "Buzz"; return input.ToString(); } } public class FizzBuzzService : IFizzBuzzService { public IFizzBuzzInput FizzBuzzInput() { return new FizzBuzzInputFromNetwork(_foo); } }

Just Two Places No `new` inline

Why? No `new` inline

Testability No `new` inline - Why?

No `new` inline - Why? - Testability public class FizzBuzz{ private readonly IFizzBuzzInput _input; public FizzBuzz() : this(new FizzBuzzInput()) { } private FizzBuzz(IFizzBuzzInput fizzBuzzInput) => _input = fizzBuzzInput; public string Result(){ if (_input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (_input.EvenlyDivisibleBy(3)) return "Fizz"; if (_input.EvenlyDivisibleBy(5)) return "Buzz"; return _input.ToString(); } }

No `new` inline - Why? - Testability public class FizzBuzz{ private readonly IFizzBuzzInput _input; public FizzBuzz() : this(new FizzBuzzInput()) { } private FizzBuzz(IFizzBuzzInput fizzBuzzInput) => _input = fizzBuzzInput; public string Result(){ if (_input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (_input.EvenlyDivisibleBy(3)) return "Fizz"; if (_input.EvenlyDivisibleBy(5)) return "Buzz"; return _input.ToString(); } } public class FizzBuzz{ private readonly IFizzBuzzService _service; public FizzBuzz() : this(new FizzBuzzService()) { } private FizzBuzz(IFizzBuzzService fizzBuzzService) => _service = fizzBuzzService; public string Result(){ IFizzBuzzInput input = _service.FizzBuzzInput(); if (input.EvenlyDivisibleBy(15)) return "FizzBuzz"; if (input.EvenlyDivisibleBy(3)) return "Fizz"; if (input.EvenlyDivisibleBy(5)) return "Buzz"; return input.ToString(); } }

Expose Existing Cohesion No `new` inline - Why?

No `new` inline - Why? - Expose Existing Cohesion public class FizzBuzz{ private readonly int _input; public FizzBuzz(int input) => _input = input; public string Result(){ if (new Mod15(_input).IsMultipleOf()) return "FizzBuzz"; if (new Mod3(_input).IsMultipleOf()) return "Fizz"; if (new Mod5(_input).IsMultipleOf()) return "Buzz"; return _input.ToString(); } }

No `new` inline - Why? - Expose Existing Cohesion public class FizzBuzz{ public FizzBuzz(int input):this(input, new Mod15(input), new Mod3(input), new Mod5(input)) public string Result(){ if (_mod15.IsMultipleOf()) return "FizzBuzz"; if (_mod3.IsMultipleOf()) return "Fizz"; if (_mod5.IsMultipleOf()) return "Buzz"; return _input.ToString(); } }

No `new` inline - Why? - Expose Existing Cohesion public class FizzBuzz{ public FizzBuzz(int input):this(new IntToString(input), new Mod15(input), new Mod3(input), new Mod5(input)) public string Result(){ if (_mod15.IsMultipleOf()) return "FizzBuzz"; if (_mod3.IsMultipleOf()) return "Fizz"; if (_mod5.IsMultipleOf()) return "Buzz"; return _toString.Value(); } }

No `new` inline - Why? - Expose Existing Cohesion public class FizzBuzz{ public FizzBuzz(int input):this(new IntToString(input), new Mod15(input), new Mod3(input), new Mod5(input)) public string Result(){ if (_mod15.IsMultipleOf()) return _mod15.Value(); if (_mod3.IsMultipleOf()) return _mod3.Value(); if (_mod5.IsMultipleOf()) return _mod5.Value(); return _toString.Value(); } }

No `new` inline - Why? - Expose Existing Cohesion public class FizzBuzz{ public FizzBuzz(int input):this(new ToStringResult(input), new FizzBuzzResult(input), new FizzResult(input), new BuzzResult(input)) public string Result(){ if (_fizzBuzz.ShouldReturn()) return _fizzBuzz.Value(); if (_buzz.ShouldReturn()) return _buzz.Value(); if (_fizz.ShouldReturn()) return _fizz.Value(); return _toString.Value(); } }

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection No `new` inline @TheQuinnGil QuinnGil.com

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection @TheQuinnGil QuinnGil.com

Feature Parity in 25% of the Dev Hours @TheQuinnGil QuinnGil.com

THANK YOU! @TheQuinnGil QuinnGil.com

Sustainable Code through Technical Practices ● No Getters / No Setters ● `if` Only As Guard Clause ● Isolate Their Code ● Never `null` ● No `new` inline ● Composition, Not Inheritance ● ● Be Immutable ● No Primitives ● Extract Cohesion ● No Public Statics ● Never Reflection @TheQuinnGil QuinnGil.com