Guava Kotlin Extensions

Extensions for Guava collections (Multimap, Multiset, Table) that allows them to be used like Kotlin's collection API. For example, to create an immutable list-based multimap, you could just either of the following:

val teamMemberLanguages = listMultimapOf("Blake" to "Kotlin", "Blake" to "Java", "Alex" to "Kotlin")
// or
val teamMemberLanguages = buildMultimap {
    putAll("Blake", listOf("Kotlin", "Java"))
    put("Alex", "Kotlin")
}

🏗️ Adding Guava Kotlin Extensions to a Project

Coming soon!

This library is not yet publishable and therefore is not available yet.

🎉 Features

Aliases

Aliases are provided for the collection types to give consistency with Kotlin naming, although these map to concrete classes, not interfaces as Guava does not provide separate mutable and immutable interfaces. Note that the inheritance hierarchy is the same as in Guava, and so the immutable ListMultimap and mutable ListMultimap both meet the Multimap interface, but are not themselves related.

Alias	Java Type
Multimap	com.google.common.collect.Multimap
ListMultimap	com.google.common.collect.ImmutableListMultimap
MutableListMultimap	com.google.common.collect.ArrayListMultimap

Support for tables and multisets is coming soon.

Creators

You can create collections using factory methods:

val favoriteNumbers = listMultimapOf("Jane" to 4, "Jane" to 5, "Eric" to 13)

or, for immutable types, using a builder:

val favoriteNumbers = buildListMultimap {
    putAll("Jane", listOf(4, 5))
    put("Eric" to 13)
    if (todayIsAMonday) put("Nicki" to 100)
}

Operators

Several operators are supported for clean syntax for accessing and modifying collections.

val favoriteNumbers = mutableListMultimapOf("Jane" to 4, "Jane" to 5)

// +  (Note this always returns a mutable copy)
val allFavoriteNumbers = favoriteNumbers + "Eric" to 13

// +=
favoriteNumbers += listOf("Nicki" to 100, "Nicki" to 12)

// in
if ("Eric" to 13 in favoriteNumbers) println("Eric's favorite number is 13!")

// get and set bracket syntax
println(favoriteNumbers["Jane"])
favoriteNumbers["Jane"] = listOf(1, 3, 3) // easy as ABC!

Extensions

You can use extension to obtain mutable or immutable copies of collections, just like with Kotlin's API, and you can obtain List<Pair> or some List representation of the collection using toList().

val favoriteNumbers = mutableListMultimapOf("Blake" to 13, "Blake" to 4, "Blake" to 13)

// Copy
val immutableCopy = favoriteNumbers.toListMultimap()
val mutableCopy = favoriteNumbers.toMutableListMultimap()

// List representation
val listRepresentation : List<Pair> = favoriteNumbers.toList()