// streams/Signal.java

// (c)2021 MindView LLC: see Copyright.txt

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

import java.util.*;

import java.util.stream.*;

import java.util.function.*;

public class Signal {

private final String msg;

public Signal(String msg) { this.msg = msg; }

public String getMsg() { return msg; }

@Override public String toString() {

return "Signal(" + msg + ")";

}

static Random rand = new Random(47);

public static Signal morse() {

switch(rand.nextInt(4)) {

case 1: return new Signal("dot");

case 2: return new Signal("dash");

default: return null;

}

}

public static Stream<Optional<Signal>> stream() {

return Stream.generate(Signal::morse)

.map(signal -> Optional.ofNullable(signal));

}

}