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You're reading from  Kotlin Design Patterns and Best Practices - Third Edition

Product typeBook
Published inApr 2024
PublisherPackt
ISBN-139781805127765
Edition3rd Edition
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Alexey Soshin
Alexey Soshin
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Alexey Soshin

Alexey Soshin is a software architect with 18 years of experience in the industry. He started exploring Kotlin when Kotlin was still in beta, and since then has been a big enthusiast of the language. He's a conference speaker, published writer, and the author of a video course titled Pragmatic System Design
Read more about Alexey Soshin

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Barrier

The Barrier design pattern enables us to pause and wait for multiple concurrent tasks to finish before moving on. This is particularly useful when assembling objects from diverse data sources.

Consider this data class:

data class FavoriteCharacter(
    val name: String,
    val catchphrase: String,
    val picture: ByteArray = Random.nextBytes(42)
)

Imagine the catchphrase comes from one service, and the picture comes from another. You’d like to fetch both data points concurrently:

fun CoroutineScope.getCatchphraseAsync(characterName: String) = async { … }
fun CoroutineScope.getPictureAsync(characterName: String) = async { … }

The most straightforward way to fetch this data concurrently would look like this:

suspend fun fetchFavoriteCharacter(name: String) = coroutineScope {
    val catchphrase = getCatchphraseAsync(name).await()
    val picture = getPictureAsync(name).await()
    FavoriteCharacter(name, catchphrase, picture)...
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Kotlin Design Patterns and Best Practices - Third Edition
Published in: Apr 2024Publisher: PacktISBN-13: 9781805127765

Author (1)

author image
Alexey Soshin

Alexey Soshin is a software architect with 18 years of experience in the industry. He started exploring Kotlin when Kotlin was still in beta, and since then has been a big enthusiast of the language. He's a conference speaker, published writer, and the author of a video course titled Pragmatic System Design
Read more about Alexey Soshin