jdk8Main.stream.Stream.kt Maven / Gradle / Ivy

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package kotlinx.coroutines.stream

import kotlinx.atomicfu.*
import kotlinx.coroutines.*
import kotlinx.coroutines.flow.*
import java.util.stream.*

/**
 * Represents the given stream as a flow and [closes][Stream.close] the stream afterwards.
 * The resulting flow can be [collected][Flow.collect] only once
 * and throws [IllegalStateException] when trying to collect it more than once.
 */
public fun  Stream.consumeAsFlow(): Flow = StreamFlow(this)

private class StreamFlow(private val stream: Stream) : Flow {
    private val consumed = atomic(false)

    override suspend fun collect(collector: FlowCollector) {
        if (!consumed.compareAndSet(false, true)) error("Stream.consumeAsFlow can be collected only once")
        try {
            for (value in stream.iterator()) {
                collector.emit(value)
            }
        } finally {
            stream.close()
        }
    }
}