Session notes from the Clean code with Java 9 talk at Geecon Krakow 2018.

geecon.jsh

1+1
int x = 1+1
System.out.println(x)
Thread.sleep(2000)
/vars
/types
/list
/l
/help
Set<String> set = new HashSet<String>()
set.add("a")
set.add("b")
set.add("c")
Collections.unmodifiableSet(set)
List<Integer> list = List.of(1,2,3)
list.add(4)
list.getClass()
Map.ofEntries(entry(1, "hello"))
/open readfile.jsh
/l readFile
/ed readFile
readFile("/tmp/geecon.txt")
new FileInputStream("/tmp/geecon.txt").transferTo(System.out)
/open myinterface.jsh
/l MyInterface
/op myclass.jsh
/l MyClass
new MyClass().abstractMethod()
new MyClass().defaultMethod()
/ed MyInterface
new MyClass().defaultMethod()
new MyClass().privateMethod()
/open diamond.jsh
/l
/ed helloSupplier
helloSupplier.get()
IntStream.iterate(0, i -> i+2).filter(j -> j<100).forEach(System.out::println)
IntStream.iterate(0, i -> i+2).limit(50).forEach(System.out::println)
IntStream.iterate(0, i -> i+2).takeWhile(j -> j<100).forEach(System.out::println)
IntStream.iterate(0, i -> i<100, i -> i+2).forEach(System.out::println)
Stream.of(1)
Stream.of(null)
Stream.ofNullable(null)
Stream.ofNullable(null).count()
Optional.empty()
Optional.of("something")
Optional.of("something").ifPresent(System.out::println)
Optional.of("something").ifPresentOrElse(System.out::println, () -> System.out.println("empty"))
Optional.empty().ifPresentOrElse(System.out::println, () -> System.out.println("empty"))
Optional.empty().orElse("empty")
Optional.empty().orElseGet(() -> "empty")
Optional.empty().or(() -> Optional.of("empty"))
Optional.empty().stream().forEach(System.out::println)
Optional.of("something").stream().forEach(System.out::println)
List.of(Optional.of(1), Optional.empty(), Optional.of(2)).stream().filter(Optional::isPresent).map(Optional::get).forEach(System.out::println)
List.of(Optional.of(1), Optional.empty(), Optional.of(2)).stream().flatMap(Optional::stream).forEach(System.out::println)
StackTraceElement[] st = new Throwable().getStackTrace()
st
StackWalker.getInstance().walk(s -> s.collect(toList()))
StackWalker.getInstance().walk(s -> s.limit(3).collect(toList()))
StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE).walk(s -> s.map(f -> f.getDeclaringClass()).collect(toList()))
StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE).walk(s -> s.map(f -> f.getDeclaringClass()).filter(c -> c.equals(jdk.jshell.execution.Util.class)).collect(toList()))
HttpHandler handler = he -> {
String body = "hello geecon";
he.sendResponseHeaders(200, body.length());
try (OutputStream os = he.getResponseBody()) {
os.write(body.getBytes());
}
}
/l
HttpServer hs = HttpServer.create(new InetSocketAddress(8000), 0)
hs.createContext("/hello", handler)
hs.start()
URI uri = new URI("http://localhost:8000/hello")
HttpURLConnection c = (HttpURLConnection) uri.toURL().openConnection()
c.setRequestMethod("GET")
c.getResponseCode()
new BufferedReader(new InputStreamReader(c.getInputStream())).readLine()
HttpClient client = HttpClient.newHttpClient()
HttpRequest request = HttpRequest.newBuilder().uri(uri).GET().build()
HttpResponse<String> response = client.send(request, BodyHandler.asString())
response.statusCode()
response.body()
CompletableFuture<HttpResponse<String>> response = client.sendAsync(request, BodyHandler.asString())
response.get().body()