New Bind Signature and GroupBy Operator

- Changed `bind` signature to match the variant discussed at ReactiveX#746 (comment)
- Updated code to new signature.
- Re-implemented GroupBy operator with `bind`

Author: benjchristensen

rxjava-core/src/main/java/rx/Observable.java

@@ -54,7 +54,7 @@
 import rx.operators.OperationFilter;
 import rx.operators.OperationFinally;
 import rx.operators.OperationFlatMap;
-import rx.operators.OperationGroupBy;
+import rx.operators.OperatorGroupBy;
 import rx.operators.OperationGroupByUntil;
 import rx.operators.OperationGroupJoin;
 import rx.operators.OperationInterval;
@@ -159,7 +159,7 @@
  */
 public class Observable<T> {
 
-    final Action2<Observer<? super T>, OperatorSubscription> f;
+    final Action1<Operator<? super T>> f;
 
     /**
      * Observable with Function to execute when subscribed to.
@@ -171,7 +171,7 @@ public class Observable<T> {
      * @param onSubscribe
      *            {@link OnSubscribeFunc} to be executed when {@link #subscribe(Observer)} is called
      */
-    protected Observable(Action2<Observer<? super T>, OperatorSubscription> f) {
+    protected Observable(Action1<Operator<? super T>> f) {
         this.f = f;
     }
 
@@ -189,31 +189,6 @@ public static interface OnSubscribeFunc<T> extends Function {
         public Subscription onSubscribe(Observer<? super T> t1);
     }
 
-    public static class OperatorSubscription implements Subscription {
-
-        private final CompositeSubscription cs = new CompositeSubscription();
-
-        @Override
-        public void unsubscribe() {
-            cs.unsubscribe();
-        }
-
-        public static OperatorSubscription create(Subscription s) {
-            OperatorSubscription _s = new OperatorSubscription();
-            _s.add(s);
-            return _s;
-        }
-
-        public boolean isUnsubscribed() {
-            return cs.isUnsubscribed();
-        }
-
-        public void add(Subscription s) {
-            cs.add(s);
-        }
-
-    }
-
     private final static RxJavaObservableExecutionHook hook = RxJavaPlugins.getInstance().getObservableExecutionHook();
 
     /**
@@ -260,27 +235,27 @@ protected Observable(Action2<Observer<? super T>, OperatorSubscription> f) {
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Creating-Observables#create">RxJava Wiki: create()</a>
      * @see <a href="http://msdn.microsoft.com/en-us/library/system.reactive.linq.observable.create.aspx">MSDN: Observable.Create</a>
      */
-    public final static <T> Observable<T> create(final Action2<Observer<? super T>, OperatorSubscription> f) {
+    public final static <T> Observable<T> create(final Action1<Operator<? super T>> f) {
         return new Observable<T>(f);
     }
 
     public final static <T> Observable<T> create(final OnSubscribeFunc<T> func) {
-        return new Observable<T>(new Action2<Observer<? super T>, OperatorSubscription>() {
+        return new Observable<T>(new Action1<Operator<? super T>>() {
 
             @Override
-            public void call(Observer<? super T> o, OperatorSubscription s) {
-                s.add(func.onSubscribe(o));
+            public void call(Operator<? super T> o) {
+                o.add(func.onSubscribe(o));
             }
 
         });
     }
 
-    public <R> Observable<R> bind(final Func2<Observer<? super R>, OperatorSubscription, Observer<? super T>> bind) {
-        return new Observable<R>(new Action2<Observer<? super R>, OperatorSubscription>() {
+    public <R> Observable<R> bind(final Func1<Operator<? super R>, Operator<? super T>> bind) {
+        return new Observable<R>(new Action1<Operator<? super R>>() {
 
             @Override
-            public void call(Observer<? super R> o, OperatorSubscription s) {
-                f.call(bind.call(o, s), s);
+            public void call(Operator<? super R> o) {
+                subscribe(bind.call(o));
             }
         });
     }
@@ -2878,7 +2853,7 @@ public final static <T> Observable<T> synchronize(Observable<T> source) {
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh229435.aspx">MSDN: Observable.Timer</a>
      */
     public final static Observable<Long> timer(long initialDelay, long period, TimeUnit unit) {
-        return timer(initialDelay, period, unit, Schedulers.threadPoolForComputation());
+        return timer(initialDelay, period, unit, Schedulers.computation());
     }
 
     /**
@@ -2917,7 +2892,7 @@ public final static Observable<Long> timer(long initialDelay, long period, TimeU
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Creating-Observables#timer">RxJava wiki: timer()</a>
      */
     public final static Observable<Long> timer(long delay, TimeUnit unit) {
-        return timer(delay, unit, Schedulers.threadPoolForComputation());
+        return timer(delay, unit, Schedulers.computation());
     }
 
     /**
@@ -4299,7 +4274,7 @@ public final <U> Observable<T> delay(Func1<? super T, ? extends Observable<U>> i
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh229810.aspx">MSDN: Observable.Delay</a>
      */
     public final Observable<T> delay(long delay, TimeUnit unit) {
-        return OperationDelay.delay(this, delay, unit, Schedulers.threadPoolForComputation());
+        return OperationDelay.delay(this, delay, unit, Schedulers.computation());
     }
 
     /**
@@ -4336,7 +4311,7 @@ public final Observable<T> delay(long delay, TimeUnit unit, Scheduler scheduler)
      *         amount
      */
     public final Observable<T> delaySubscription(long delay, TimeUnit unit) {
-        return delaySubscription(delay, unit, Schedulers.threadPoolForComputation());
+        return delaySubscription(delay, unit, Schedulers.computation());
     }
 
     /**
@@ -4795,7 +4770,7 @@ public final <R> Observable<R> flatMap(Func1<? super T, ? extends Observable<? e
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Transforming-Observables#groupby-and-groupbyuntil">RxJava Wiki: groupBy</a>
      */
     public final <K> Observable<GroupedObservable<K, T>> groupBy(final Func1<? super T, ? extends K> keySelector) {
-        return create(OperationGroupBy.groupBy(this, keySelector));
+        return bind(new OperatorGroupBy<K, T>(keySelector));
     }
 
     /**
@@ -4819,7 +4794,7 @@ public final <K> Observable<GroupedObservable<K, T>> groupBy(final Func1<? super
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Transforming-Observables#groupby-and-groupbyuntil">RxJava Wiki: groupBy</a>
      */
     public final <K, R> Observable<GroupedObservable<K, R>> groupBy(final Func1<? super T, ? extends K> keySelector, final Func1<? super T, ? extends R> elementSelector) {
-        return create(OperationGroupBy.groupBy(this, keySelector, elementSelector));
+        return null;
     }
 
     /**
@@ -5936,7 +5911,7 @@ public final Subject<T, T> call() {
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh228952.aspx">MSDN: Observable.Replay</a>
      */
     public final <R> Observable<R> replay(Func1<? super Observable<T>, ? extends Observable<R>> selector, int bufferSize, long time, TimeUnit unit) {
-        return replay(selector, bufferSize, time, unit, Schedulers.threadPoolForComputation());
+        return replay(selector, bufferSize, time, unit, Schedulers.computation());
     }
 
     /**
@@ -6036,7 +6011,7 @@ public final Subject<T, T> call() {
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh229526.aspx">MSDN: Observable.Replay</a>
      */
     public final <R> Observable<R> replay(Func1<? super Observable<T>, ? extends Observable<R>> selector, long time, TimeUnit unit) {
-        return replay(selector, time, unit, Schedulers.threadPoolForComputation());
+        return replay(selector, time, unit, Schedulers.computation());
     }
 
     /**
@@ -6139,7 +6114,7 @@ public final ConnectableObservable<T> replay(int bufferSize) {
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh229874.aspx">MSDN: Observable.Replay</a>
      */
     public final ConnectableObservable<T> replay(int bufferSize, long time, TimeUnit unit) {
-        return replay(bufferSize, time, unit, Schedulers.threadPoolForComputation());
+        return replay(bufferSize, time, unit, Schedulers.computation());
     }
 
     /**
@@ -6209,7 +6184,7 @@ public final ConnectableObservable<T> replay(int bufferSize, Scheduler scheduler
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh229232.aspx">MSDN: Observable.Replay</a>
      */
     public final ConnectableObservable<T> replay(long time, TimeUnit unit) {
-        return replay(time, unit, Schedulers.threadPoolForComputation());
+        return replay(time, unit, Schedulers.computation());
     }
 
     /**
@@ -6516,7 +6491,7 @@ public final Observable<T> skip(int num) {
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Filtering-Observables#skip">RxJava Wiki: skip()</a>
      */
     public final Observable<T> skip(long time, TimeUnit unit) {
-        return skip(time, unit, Schedulers.threadPoolForComputation());
+        return skip(time, unit, Schedulers.computation());
     }
 
     /**
@@ -6578,7 +6553,7 @@ public final Observable<T> skipLast(int count) {
      * @see <a href="http://msdn.microsoft.com/en-us/library/hh211750.aspx">MSDN: Observable.SkipLast</a>
      */
     public final Observable<T> skipLast(long time, TimeUnit unit) {
-        return skipLast(time, unit, Schedulers.threadPoolForComputation());
+        return skipLast(time, unit, Schedulers.computation());
     }
 
     /**
@@ -6929,8 +6904,8 @@ public final Observable<T> startWith(T[] values, Scheduler scheduler) {
     }
 
     // TODO should this be called `observe` instead of `subscribe`?
-    public final void subscribe(Observer<? super T> o, Func0<OperatorSubscription> sf) {
-        f.call(o, sf.call());
+    public final void subscribe(Operator<? super T> o) {
+        f.call(o);
     }
 
     /**
@@ -7166,7 +7141,7 @@ public final Subscription subscribe(final Action1<? super T> onNext, Scheduler s
      */
     public final Subscription subscribe(Observer<? super T> observer) {
         // allow the hook to intercept and/or decorate
-        Action2<Observer<? super T>, OperatorSubscription> onSubscribeFunction = hook.onSubscribeStart(this, f);
+        Action1<Operator<? super T>> onSubscribeFunction = hook.onSubscribeStart(this, f);
         // validate and proceed
         if (observer == null) {
             throw new IllegalArgumentException("observer can not be null");
@@ -7176,17 +7151,20 @@ public final Subscription subscribe(Observer<? super T> observer) {
             // the subscribe function can also be overridden but generally that's not the appropriate approach so I won't mention that in the exception
         }
         try {
-            OperatorSubscription os = new OperatorSubscription();
+            Operator<? super T> op = null;
             /**
              * See https://github.com/Netflix/RxJava/issues/216 for discussion on "Guideline 6.4: Protect calls to user code from within an operator"
              */
             if (isInternalImplementation(observer)) {
-                onSubscribeFunction.call(observer, os);
+                op = Operator.create(observer, new CompositeSubscription());
+                onSubscribeFunction.call(op);
             } else {
-                SafeObservableSubscription subscription = new SafeObservableSubscription(os);
-                onSubscribeFunction.call(new SafeObserver<T>(subscription, observer), os);
+                // TODO this doesn't seem correct any longer with the Operator and injecting of CompositeSubscription
+                SafeObservableSubscription subscription = new SafeObservableSubscription(op);
+                op = Operator.create(new SafeObserver<T>(subscription, observer), new CompositeSubscription());
+                onSubscribeFunction.call(op);
             }
-            return hook.onSubscribeReturn(this, os);
+            return hook.onSubscribeReturn(this, op);
         } catch (OnErrorNotImplementedException e) {
             // special handling when onError is not implemented ... we just rethrow
             throw e;
@@ -7426,7 +7404,7 @@ public final Observable<T> take(final int num) {
      * @see <a href="https://github.com/Netflix/RxJava/wiki/Filtering-Observables#take">RxJava Wiki: take()</a>
      */
     public final Observable<T> take(long time, TimeUnit unit) {
-        return take(time, unit, Schedulers.threadPoolForComputation());
+        return take(time, unit, Schedulers.computation());
     }
 
     /**
@@ -7517,7 +7495,7 @@ public final Observable<T> takeLast(final int count) {
      *         were emitted in a specified window of time before the Observable completed.
      */
     public final Observable<T> takeLast(int count, long time, TimeUnit unit) {
-        return takeLast(count, time, unit, Schedulers.threadPoolForComputation());
+        return takeLast(count, time, unit, Schedulers.computation());
     }
 
     /**
@@ -7560,7 +7538,7 @@ public final Observable<T> takeLast(int count, long time, TimeUnit unit, Schedul
      *         the window of time before the Observable completed specified by {@code time}
      */
     public final Observable<T> takeLast(long time, TimeUnit unit) {
-        return takeLast(time, unit, Schedulers.threadPoolForComputation());
+        return takeLast(time, unit, Schedulers.computation());
     }
 
     /**
@@ -8735,10 +8713,10 @@ public final <T2, R> Observable<R> zip(Observable<? extends T2> other, Func2<? s
      */
     private static class NeverObservable<T> extends Observable<T> {
         public NeverObservable() {
-            super(new Action2<Observer<? super T>, OperatorSubscription>() {
+            super(new Action1<Operator<? super T>>() {
 
                 @Override
-                public void call(Observer<? super T> observer, OperatorSubscription t2) {
+                public void call(Operator<? super T> observer) {
                     // do nothing
                 }
 
@@ -8756,7 +8734,7 @@ public void call(Observer<? super T> observer, OperatorSubscription t2) {
     private static class ThrowObservable<T> extends Observable<T> {
 
         public ThrowObservable(final Throwable exception) {
-            super(new Action2<Observer<? super T>, OperatorSubscription>() {
+            super(new Action1<Operator<? super T>>() {
 
                 /**
                  * Accepts an {@link Observer} and calls its {@link Observer#onError onError} method.
@@ -8766,14 +8744,15 @@ public ThrowObservable(final Throwable exception) {
                  * @return a reference to the subscription
                  */
                 @Override
-                public void call(Observer<? super T> observer, OperatorSubscription t2) {
+                public void call(Operator<? super T> observer) {
                     observer.onError(exception);
                 }
 
             });
         }
     }
 
+    @SuppressWarnings("rawtypes")
     private final static ConcurrentHashMap<Class, Boolean> internalClassMap = new ConcurrentHashMap<Class, Boolean>();
 
     /**

rxjava-core/src/main/java/rx/observables/ConnectableObservable.java

@@ -17,9 +17,10 @@
 
 import rx.Observable;
 import rx.Observer;
+import rx.Operator;
 import rx.Subscription;
 import rx.operators.OperationRefCount;
-import rx.util.functions.Action2;
+import rx.util.functions.Action1;
 
 /**
  * A ConnectableObservable resembles an ordinary {@link Observable}, except that it does not begin
@@ -38,7 +39,7 @@
 
 public abstract class ConnectableObservable<T> extends Observable<T> {
 
-    protected ConnectableObservable(Action2<Observer<? super T>, OperatorSubscription> onSubscribe) {
+    protected ConnectableObservable(Action1<Operator<? super T>> onSubscribe) {
         super(onSubscribe);
     }
 

rxjava-core/src/main/java/rx/observables/GroupedObservable.java

@@ -16,8 +16,8 @@
 package rx.observables;
 
 import rx.Observable;
-import rx.Observer;
-import rx.util.functions.Action2;
+import rx.Operator;
+import rx.util.functions.Action1;
 import rx.util.functions.Func1;
 
 /**
@@ -33,7 +33,7 @@
 public class GroupedObservable<K, T> extends Observable<T> {
     private final K key;
 
-    public GroupedObservable(K key, Action2<Observer<? super T>, OperatorSubscription> onSubscribe) {
+    public GroupedObservable(K key, Action1<Operator<? super T>> onSubscribe) {
         super(onSubscribe);
         this.key = key;
     }