rxjava : operator, async

RxJava/ReactiveStream/src/main/java/AsyncEx.java

@@ -0,0 +1,39 @@
+import io.reactivex.rxjava3.core.Flowable;
+
+import java.util.concurrent.TimeUnit;
+
+public class AsyncEx {
+
+    private enum State {
+        ADD, MULTIPLY
+    }
+
+    private static State calcMethod;
+
+    public static void main(String[] args) throws InterruptedException {
+
+        calcMethod = State.ADD;
+
+        Flowable<Long> flowable =
+                Flowable.interval(300L, TimeUnit.MILLISECONDS)
+                        .take(7)
+                        .scan((sum, data) -> {
+                            if (calcMethod == State.ADD) {
+                                return sum + data;
+                            } else {
+                                return sum * data;
+                            }
+                        });
+
+        // 구독 후 받은 데이터 출력
+        flowable.subscribe(data -> System.out.println("data = " + data));
+
+        // Sleep 후 계산법 변경
+        // Bad case -> 외부의 데이터가 계산에 영향을 주면 안된다.
+        Thread.sleep(1000);
+        System.out.println("계산법 변경");
+        calcMethod = State.MULTIPLY;
+
+        Thread.sleep(2000);
+    }
+}

RxJava/ReactiveStream/src/main/java/OperatorEx.java

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+import io.reactivex.rxjava3.core.Flowable;
+
+public class OperatorEx {
+
+    public static void main(String[] args) {
+
+        Flowable<Integer> flowable =
+                Flowable.just(1, 2, 3, 4, 5, 6, 7, 8)
+                        .filter(data -> data % 2 == 0 )
+                        .map(data -> data * 2);
+
+        flowable.subscribe(data -> System.out.println("data = " + data));
+    }
+}