45c826a218
Introduces a materializer started through an extension and then an implicit conversion for Scala turning an implicitly available ActorSystem into a materializer. The Java APIs has been ammended with run-methods accepting an ActorSystem.
85 lines
2.8 KiB
Java
85 lines
2.8 KiB
Java
/*
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* Copyright (C) 2018-2019 Lightbend Inc. <https://www.lightbend.com>
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*/
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package jdocs.stream.operators;
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import akka.NotUsed;
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import akka.actor.ActorSystem;
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import akka.stream.javadsl.Sink;
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import akka.stream.javadsl.Source;
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// #takeLast-operator-example
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import akka.japi.Pair;
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// #takeLast-operator-example
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import java.util.*;
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import java.util.concurrent.CompletionStage;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.TimeoutException;
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public class SinkDocExamples {
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private static final ActorSystem system = ActorSystem.create("SourceFromExample");
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static void reduceExample() throws InterruptedException, ExecutionException, TimeoutException {
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// #reduce-operator-example
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Source<Integer, NotUsed> ints = Source.from(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
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CompletionStage<Integer> sum = ints.runWith(Sink.reduce((a, b) -> a + b), system);
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sum.thenAccept(System.out::println);
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// 55
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// #reduce-operator-example
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}
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static void takeLastExample() throws InterruptedException, ExecutionException, TimeoutException {
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// #takeLast-operator-example
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// pair of (Name, GPA)
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List<Pair> sortedStudents =
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Arrays.asList(
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new Pair<>("Benita", 2.1),
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new Pair<>("Adrian", 3.1),
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new Pair<>("Alexis", 4),
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new Pair<>("Kendra", 4.2),
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new Pair<>("Jerrie", 4.3),
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new Pair<>("Alison", 4.7));
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Source<Pair, NotUsed> studentSource = Source.from(sortedStudents);
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CompletionStage<List<Pair>> topThree = studentSource.runWith(Sink.takeLast(3), system);
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topThree.thenAccept(
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result -> {
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System.out.println("#### Top students ####");
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for (int i = result.size() - 1; i >= 0; i--) {
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Pair<String, Double> s = result.get(i);
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System.out.println("Name: " + s.first() + ", " + "GPA: " + s.second());
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}
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});
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/*
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#### Top students ####
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Name: Alison, GPA: 4.7
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Name: Jerrie, GPA: 4.3
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Name: Kendra, GPA: 4.2
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*/
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// #takeLast-operator-example
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}
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static void lastExample() throws InterruptedException, ExecutionException, TimeoutException {
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// #last-operator-example
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Source<Integer, NotUsed> source = Source.from(Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
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CompletionStage<Integer> result = source.runWith(Sink.last(), system);
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result.thenAccept(System.out::println);
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// 10
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// #last-operator-example
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}
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static void lastOptionExample()
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throws InterruptedException, ExecutionException, TimeoutException {
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// #lastOption-operator-example
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Source<Integer, NotUsed> source = Source.empty();
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CompletionStage<Optional<Integer>> result = source.runWith(Sink.lastOption(), system);
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result.thenAccept(System.out::println);
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// Optional.empty
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// #lastOption-operator-example
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}
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}
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