rxjava : cold publisher, hot publisher

RxJava/ReactiveStream/src/main/java/ColdPublisherEx.java

@@ -0,0 +1,13 @@
+import io.reactivex.rxjava3.core.Flowable;
+
+public class ColdPublisherEx {
+
+    public static void main(String[] args) {
+
+        Flowable<Integer> flowable = Flowable.just(1, 2, 3, 4);
+
+        // 구독시 처음부터 타임라인을 재구성하여 모든 데이터를 받을 수 있다.
+        flowable.subscribe(data -> System.out.println("data = " + data));
+        flowable.subscribe(data -> System.out.println("data = " + data));
+    }
+}

RxJava/ReactiveStream/src/main/java/HotPublisherEx.java

@@ -0,0 +1,18 @@
+import io.reactivex.rxjava3.processors.PublishProcessor;
+
+public class HotPublisherEx {
+
+    public static void main(String[] args) {
+
+        PublishProcessor<Integer> processor = PublishProcessor.create();
+        processor.subscribe(data -> System.out.println("subscribe1 = " + data));
+        processor.onNext(1);
+        processor.onNext(2);
+
+        // 구독한 시점 이후의 데이터만 받을 수 있다.
+        processor.subscribe(data -> System.out.println("subscribe2 = " + data));
+        processor.onNext(3);
+        processor.onNext(4);
+
+    }
+}