name.remal.java.util.stream.Stream.kt Maven / Gradle / Ivy

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package name.remal

import java.util.*
import java.util.stream.Collectors
import java.util.stream.Stream
import java.util.stream.StreamSupport
import kotlin.collections.LinkedHashSet

fun  emptyStream(): Stream = Stream.of()
fun  streamOf(): Stream = Stream.of()
fun  streamOf(vararg elements: T): Stream = Stream.of(*elements)

fun  Array.stream(): Stream = Arrays.stream(this)

operator fun  Stream.plus(other: Stream): Stream = Stream.concat(this, other)

fun  Stream.filterNotNull(): Stream = filter { null != it }.uncheckedCast()
fun  Stream.filterIsInstance(type: Class): Stream = filter { type.isInstance(it) }.uncheckedCast()
inline fun  Stream.filterIsInstance(): Stream = filterIsInstance(R::class.java)

@JvmName("flatMapCollection")
fun  Stream.flatMap(mapper: (T) -> Collection): Stream = this.flatMap { mapper(it).stream() }

@JvmName("flatMapIterable")
fun  Stream.flatMap(mapper: (T) -> Iterable): Stream = this.flatMap { StreamSupport.stream(mapper(it).spliterator(), false) }


fun  Stream.firstOrNull(): T? = findFirst().orNull

fun  Stream.asIterable(): Iterable = object : Iterable {
    override fun iterator() = [email protected]()
}

fun  Stream.toList(): List = collect(Collectors.toList())
fun  Stream.toSet(): Set = collect(Collectors.toCollection(::LinkedHashSet))
fun  Stream.toHashSet(): Set = collect(Collectors.toCollection(::HashSet))
fun > Stream.toSortedSet(): SortedSet = collect(Collectors.toCollection { TreeSet() })
fun > Stream.toMap(): Map = collect(Collectors.toMap({ it.first }, { it.second }, { _, value -> value }, ::LinkedHashMap))
fun > Stream.toHashMap(): Map = collect(Collectors.toMap({ it.first }, { it.second }, { _, value -> value }, ::HashMap))
fun , V, T : Pair> Stream.toHashMap(): SortedMap = collect(Collectors.toMap({ it.first }, { it.second }, { _, value -> value }, ::TreeMap))

@JvmName("joinCharSequencesToString")
fun  Stream.joinToString(separator: CharSequence = ", ", prefix: CharSequence = "", postfix: CharSequence = ""): String = collect(Collectors.joining(separator, prefix, postfix))

fun  Stream.joinToString(separator: CharSequence = ", ", prefix: CharSequence = "", postfix: CharSequence = ""): String = map { "$it" }.joinToString(separator, prefix, postfix)

fun > Stream.max(): T? = max(Comparator.naturalOrder()).orNull
fun > Stream.min(): T? = min(Comparator.naturalOrder()).orNull

fun  Stream.reduce(reducer: (first: T, second: T) -> T): T? = collect(Collectors.reducing(reducer)).orNull