deyou
65 lines
1.9 KiB
Java
65 lines
1.9 KiB
Java
package streams;
|
|
|
|
import java.io.IOException;
|
|
import java.math.BigInteger;
|
|
import java.nio.charset.StandardCharsets;
|
|
import java.nio.file.Files;
|
|
import java.nio.file.Path;
|
|
import java.nio.file.Paths;
|
|
import java.util.List;
|
|
import java.util.regex.Pattern;
|
|
import java.util.stream.Collectors;
|
|
import java.util.stream.Stream;
|
|
|
|
public class CreatingStreams
|
|
{
|
|
public static <T> void show(String title, Stream<T> stream)
|
|
{
|
|
final int SIZE = 10;
|
|
List<T> firstElements = stream
|
|
.limit(SIZE + 1)
|
|
.collect(Collectors.toList());
|
|
System.out.print(title + ": ");
|
|
for (int i = 0; i < firstElements.size(); i++)
|
|
{
|
|
if (i > 0) System.out.print(", ");
|
|
if (i < SIZE) System.out.print(firstElements.get(i));
|
|
else System.out.print("...");
|
|
}
|
|
System.out.println();
|
|
}
|
|
|
|
public static void main(String[] args) throws IOException
|
|
{
|
|
Path path = Paths.get("../gutenberg/alice30.txt");
|
|
String contents = new String(Files.readAllBytes(path),
|
|
StandardCharsets.UTF_8);
|
|
|
|
Stream<String> words = Stream.of(contents.split("\\PL+"));
|
|
show("words", words);
|
|
Stream<String> song = Stream.of("gently", "down", "the", "stream");
|
|
show("song", song);
|
|
Stream<String> silence = Stream.empty();
|
|
show("silence", silence);
|
|
|
|
Stream<String> echos = Stream.generate(() -> "Echo");
|
|
show("echos", echos);
|
|
|
|
Stream<Double> randoms = Stream.generate(Math::random);
|
|
show("randoms", randoms);
|
|
|
|
Stream<BigInteger> integers = Stream.iterate(BigInteger.ONE,
|
|
n -> n.add(BigInteger.ONE));
|
|
show("integers", integers);
|
|
|
|
Stream<String> wordsAnotherWay = Pattern.compile("\\PL+").splitAsStream(
|
|
contents);
|
|
show("wordsAnotherWay", wordsAnotherWay);
|
|
|
|
try (Stream<String> lines = Files.lines(path, StandardCharsets.UTF_8))
|
|
{
|
|
show("lines", lines);
|
|
}
|
|
}
|
|
}
|