Add Completable.andThen(Completable), deprecate endWith() (ReactiveX#3948)

Closes ReactiveX#3947

Author: vanniktech

src/main/java/rx/Completable.java

@@ -1132,6 +1132,19 @@ public final <T> Single<T> andThen(Single<T> next) {
         requireNonNull(next);
         return next.delaySubscription(toObservable());
     }
+
+    /**
+     * Returns a completable that first runs this Completable
+     * and then the other completable.
+     * <p>
+     * This is an alias for {@link #concatWith(Completable)}.
+     * @param next the other Completable, not null
+     * @return the new Completable instance
+     * @throws NullPointerException if other is null
+     */
+    public final Completable andThen(Completable next) {
+        return concatWith(next);
+    }
 
     /**
      * Concatenates this Completable with another Completable.
@@ -1396,20 +1409,23 @@ public void call(Throwable e) {
      * @param other the other Completable, not null
      * @return the new Completable instance
      * @throws NullPointerException if other is null
+     * @deprecated Use {@link #andThen(rx.Completable)} instead.
      */
+    @Deprecated
     public final Completable endWith(Completable other) {
-        return concatWith(other);
+        return andThen(other);
     }
 
     /**
      * Returns an Observable that first runs this Completable instance and
      * resumes with the given next Observable.
      * @param next the next Observable to continue
      * @return the new Observable instance
-     * @throws NullPointerException if next is null
+     * @deprecated Use {@link #andThen(rx.Observable)} instead.
      */
+    @Deprecated
     public final <T> Observable<T> endWith(Observable<T> next) {
-        return next.startWith(this.<T>toObservable());
+        return andThen(next);
     }
 
     /**

src/test/java/rx/CompletableTest.java

@@ -3530,20 +3530,20 @@ public void startWithFlowableNull() {
     }
 
     @Test(expected = NullPointerException.class)
-    public void endWithCompletableNull() {
-        normal.completable.endWith((Completable)null);
+    public void andThenCompletableNull() {
+        normal.completable.andThen((Completable)null);
     }
 
     @Test(expected = NullPointerException.class)
-    public void endWithFlowableNull() {
-        normal.completable.endWith((Observable<Object>)null);
+    public void andThenFlowableNull() {
+        normal.completable.andThen((Observable<Object>)null);
     }
 
     @Test(timeout = 1000)
-    public void endWithCompletableNormal() {
+    public void andThenCompletableNormal() {
         final AtomicBoolean run = new AtomicBoolean();
         Completable c = normal.completable
-                .endWith(Completable.fromCallable(new Callable<Object>() {
+                .andThen(Completable.fromCallable(new Callable<Object>() {
                     @Override
                     public Object call() throws Exception {
                         run.set(normal.get() == 0);
@@ -3558,8 +3558,8 @@ public Object call() throws Exception {
     }
 
     @Test(timeout = 1000)
-    public void endWithCompletableError() {
-        Completable c = normal.completable.endWith(error.completable);
+    public void andThenCompletableError() {
+        Completable c = normal.completable.andThen(error.completable);
 
         try {
             c.await();
@@ -3571,10 +3571,10 @@ public void endWithCompletableError() {
     }
 
     @Test(timeout = 1000)
-    public void endWithFlowableNormal() {
+    public void andThenFlowableNormal() {
         final AtomicBoolean run = new AtomicBoolean();
         Observable<Object> c = normal.completable
-                .endWith(Observable.fromCallable(new Callable<Object>() {
+                .andThen(Observable.fromCallable(new Callable<Object>() {
                     @Override
                     public Object call() throws Exception {
                         run.set(normal.get() == 0);
@@ -3595,9 +3595,9 @@ public Object call() throws Exception {
     }
 
     @Test(timeout = 1000)
-    public void endWithFlowableError() {
+    public void andThenFlowableError() {
         Observable<Object> c = normal.completable
-                .endWith(Observable.error(new TestException()));
+                .andThen(Observable.error(new TestException()));
 
         TestSubscriber<Object> ts = new TestSubscriber<Object>();