kotlin.collections.SequencesJVM.kt Maven / Gradle / Ivy

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Kotlin Standard Library for JVM

There is a newer version: 2.1.0-Beta1

/*
 * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
 * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
 */

@file:kotlin.jvm.JvmMultifileClass
@file:kotlin.jvm.JvmName("SequencesKt")

package kotlin.sequences

/**
 * Creates a sequence that returns all values from this enumeration. The sequence is constrained to be iterated only once.
 * @sample samples.collections.Sequences.Building.sequenceFromEnumeration
 */
@kotlin.internal.InlineOnly
public inline fun  java.util.Enumeration.asSequence(): Sequence = this.iterator().asSequence()


internal actual class ConstrainedOnceSequence actual constructor(sequence: Sequence) : Sequence {
    private val sequenceRef = java.util.concurrent.atomic.AtomicReference(sequence)

    actual override fun iterator(): Iterator {
        val sequence = sequenceRef.getAndSet(null) ?: throw IllegalStateException("This sequence can be consumed only once.")
        return sequence.iterator()
    }
}