if I have to write a

ByteBuffer

to file, what's the best way? Using

InputStream

like here: https://stackoverflow.com/questions/35528409/write-a-large-inputstream-to-file-in-kotlin?

Embrace `java.nio`:

fun Path.channel(vararg options: OpenOption): FileChannel = FileChannel.open(this, *options)

fun main(args: Array<String>) {
    val buf: ByteBuffer = TODO()
    val file = Paths.get("output")

    file.channel(StandardOpenOption.CREATE, StandardOpenOption.WRITE).use { channel ->
        while (buf.hasRemaining()) channel.write(buf)
    }
}

why

while (buf.hasRemaining())

and not simply

channel.write(buf)

?

Yes,

channel.write

may write only a portion of the buffer as per the Javadocs.

what does it mean?

Channel

is a very generic interface. It might be a channel bound to a network socket, which only has a limited buffer. You can't just send out 500MB immediately, you have to wait for the network speed. So as long as the network buffer is full, it cannot write.

ah, that makes sense, thanks

Yes, but why

also

here?