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Updated with initial fluent builder addtion

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garywoodfine committed May 6, 2019
1 parent 0d9e82b commit 164275e859006c8a31a059aee24431c179fd6177
Showing with 35 additions and 16 deletions.
  1. +25 −2 Builder/
  2. +1 −1 Builder/src/Person.cs
  3. +9 −13 Builder/src/PersonBuilder.cs
@@ -169,7 +169,7 @@ public override string ToString()=>
the `Build` or `Create` to define the method that will return your object, but you don't really need to rather you
could opt for another name, in the case of StringBuilder it is `ToString()`

### More complex Builder Pattern implementation
### Fluent Builder Pattern implementation

In the above example we have implemented a simple builder patter, however it probably isn't easy to determine why this
actually provides any benefit to developers. After all,from this simple implementation you might be thinking but surely
@@ -202,7 +202,30 @@ public override string ToString()=>

The Builder pattern is applicable when the algorithm for creating a complex object should be independent of the parts
that make up the object and how they are assembled and the construction process must allow different representations
for the object constructed
for the object constructed.

If we consider a person object and think of all the different variations we could expect to create a person object.
For instance, how do we deal with married woman? Considering in some cases we may need to take into consideration her
maiden name. How do we cater for trans-gender people? It soon becomes clear that there are all manner of rules and
variations we need to consider when build a person object. All manner of varying combinations and all sorts of
additional properties we will need to include. Rules that may not be easy or convenient to incorporate in object

In our first implementation of builder for a fluent interface of the Person class, we implemented the builder with no
strings attached. We have not enforced rules for the order of assignment.

The code is simple and easy to understand but it does leave the builder class open to misuse. We can implement the
basic expression builder with method chaining in C# .NET.

We're going to refactor our builder slightly to incorporate a new method `Create` which will accept Firstname and
Lastname argument but more importantly we are going to remove the creation of the `Person` class from the constructor
and into `Create` method.

It also doesn't make much sense providing and Id to an object on creation, it is highly likely that a new Id should be
created when the object is created. So we'll also remove the Id parameter from the Builder.

### Summary

@@ -5,7 +5,7 @@ namespace BuilderPattern
public class Person
public int Id { get; set; }
public Guid Id { get; set; }

public string Firstname { get; set; }

@@ -4,31 +4,27 @@ namespace BuilderPattern
public class PersonBuilder
private readonly Person _person;
private Person _person;

public PersonBuilder()
_person = new Person();

public PersonBuilder Id(int id)
_person.Id = id;
return this;

public PersonBuilder Firstname(string firstName)
public PersonBuilder Create(string firstName, string lastName)
_person = new Person();
_person.Firstname = firstName;
_person.Lastname = lastName;
_person.Id = Guid.NewGuid();
return this;

public PersonBuilder Lastname(string lastname)
_person.Lastname = lastname;
return this;

public PersonBuilder DateOfBirth( DateTime dob)
_person.DateOfBirth = dob;

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