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The first thing that we are going to discuss about is the builder factor, so the builder pattern is

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a technique that is widely used by software engineers when trying to manage the creation of complex

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objects.

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But what exactly do we need to use the builder, Patrick?

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Well, our situation would be when trying to create complex objects, that requires a lot of parameters,

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especially when those parameters need to be supplied at any summarisation phase.

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So in a constructor, for example, or when trying to prevent mistakes from creating a complex object

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by supplying the parameters that we need to supply in a different order than the one that is expected.

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And also when trying to avoid unreadable code that is caused by big constructors, when those big constructors

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are needed in order to create some really, really complicated objects in our program, let's see a

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typical issue that can be solved by using the builder pattern in the code.

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So let's assume that we are working on an online store application, so the most complex object that

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I can think of is the user account for our online store.

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So like most of those stores, we are collecting some data regarding the user.

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So we are assigning an ID for it.

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We also collect the names you address, the budget and the discount rate that we may apply to to this

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user.

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And this is, of course, another simplified example, because applications tend to be more complex

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than to have more complex objects inside them.

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So now you can see this constructor here.

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It's it doesn't look good at all.

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It has a long list of parameters that we need to supply in it.

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So this is considered to be a bad practice, right.

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Because you can easily mistake the order of the parameters so you can easily put inside the budget.

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You can put other parameters like we will see in in the example.

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So you should avoid this type of these types of constructors right.

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In your code.

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But you can see it's pretty straightforward.

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So we are assigning the ID, the name, the address budget in this country to each and every property

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of this class.

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So let's see in the upper class here where we have the main method, we created two objects, two users.

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The first one is John Smith.

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And here we are saying I need a name and address, a budget and also a discount rate.

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So basically, this user, we have a discount of two percent to our products.

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And for the second one, you can see that it's pretty much the same except for the data itself.

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But here we have the budget of two and a discount rate of 100 percent.

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So basically we reduced the budget of the user and also we applied a discount of 100 percent to everything

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that this user will be buying.

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So this this is actually an example of mistakingly putting the wrong parameters in the wrong border.

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So we need to find a way to prevent this type of mistake.

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And by the way, if you know such such an application, such an online store, just let me know, because

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this this can be a very useful issue to exploit.

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Right.

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So joining me in the next video where we are going to talk about how exactly we can prevent such such

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an error.