@Test
public void demonstrateCustomSourceUsage() throws Exception {
// #simple-source-usage
// A GraphStage is a proper Graph, just like what GraphDSL.create would return
Graph<SourceShape<Integer>, NotUsed> sourceGraph = new NumbersSource();
// Create a Source from the Graph to access the DSL
Source<Integer, NotUsed> mySource = Source.fromGraph(sourceGraph);
// Returns 55
CompletionStage<Integer> result1 = mySource.take(10).runFold(0, (sum, next) -> sum + next, mat);
// The source is reusable. This returns 5050
CompletionStage<Integer> result2 =
mySource.take(100).runFold(0, (sum, next) -> sum + next, mat);
// #simple-source-usage
assertEquals(result1.toCompletableFuture().get(3, TimeUnit.SECONDS), (Integer) 55);
assertEquals(result2.toCompletableFuture().get(3, TimeUnit.SECONDS), (Integer) 5050);
}
