WEBVTT

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Welcome back.

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We need to handle the possible states of asynchronous operation like loading success and failure.

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For this purpose, I'm going to create a new package inside the data package.

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Name it as util.

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Inside this util, create a new Kotlin class, name it as response and make it as a sealed class.

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So this is the class response sealed class and the type of parameter is out t.

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Don't worry, we're gonna clarify everything here.

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We have a data object loading returning type or its type response.

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Nothing.

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Data class success val data its response and data class failure val error exception.

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Its of type exception.

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The response is nothing.

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This data class response represents the possible states of an asynchronous operation or API response.

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Our D indicates that the type parameter t is covariant, so you can use response of type dog.

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Response of type animal where response of any, for example any variant.

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So the dog where animal is expected can be replaced by this.

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And when using T we are using a generic wrapper for operation results.

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Again guys out T this is the first time we use.

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It indicates that the type parameter t is covariant, where you can use a response of type dog where

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response of type animal is expected.

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Okay, this is the main idea behind using T, because we can pass anything that inherits from the main

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t, we have three possible states loading, success and failure.

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Loading.

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Operation is in progress.

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No data available yet and nothing.

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Type means it contains no value, so let me write it down.

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Success.

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Operation completed successfully contains the result data of type T and.

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For example, you can make it a success of user data success a list of items.

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And in this application we need success of list of items.

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So here it contains the result data of type T failure.

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Operation failed contains an operation exception explained what went wrong.

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Nothing.

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Type indicates that no no success data and it doesn't contain any data.

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So we used the sealed class response.

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And this is a pattern that is widely used in Android MVVM architectures.

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And it provides a clean type safe way to handle asynchronous operations and UI states.