3.x: [Java 8] Add AutoCloseable <-> Disposable conversions, nicen docs (#6780)

Author: akarnokd

src/main/java/io/reactivex/rxjava3/disposables/ActionDisposable.java

@@ -17,7 +17,7 @@
 import io.reactivex.rxjava3.internal.util.ExceptionHelper;
 
 /**
- * A Disposable container that manages an Action instance.
+ * A Disposable container that manages an {@link Action} instance.
  */
 final class ActionDisposable extends ReferenceDisposable<Action> {
 
@@ -35,4 +35,9 @@ protected void onDisposed(@NonNull Action value) {
             throw ExceptionHelper.wrapOrThrow(ex);
         }
     }
+
+    @Override
+    public String toString() {
+        return "ActionDisposable(disposed=" + isDisposed() + ", " + get() + ")";
+    }
 }

src/main/java/io/reactivex/rxjava3/disposables/AutoCloseableDisposable.java

@@ -0,0 +1,45 @@
+/**
+ * Copyright (c) 2016-present, RxJava Contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
+ * the License for the specific language governing permissions and limitations under the License.
+ */
+
+package io.reactivex.rxjava3.disposables;
+
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.plugins.RxJavaPlugins;
+
+/**
+ * A disposable container that manages an {@link AutoCloseable} instance.
+ * @since 3.0.0
+ */
+final class AutoCloseableDisposable extends ReferenceDisposable<AutoCloseable> {
+
+    private static final long serialVersionUID = -6646144244598696847L;
+
+    AutoCloseableDisposable(AutoCloseable value) {
+        super(value);
+    }
+
+    @Override
+    protected void onDisposed(@NonNull AutoCloseable value) {
+        try {
+            value.close();
+        } catch (Throwable ex) {
+            RxJavaPlugins.onError(ex);
+        }
+    }
+
+    @Override
+    public String toString() {
+        return "AutoCloseableDisposable(disposed=" + isDisposed() + ", " + get() + ")";
+    }
+
+}

src/main/java/io/reactivex/rxjava3/disposables/Disposables.java

@@ -35,8 +35,8 @@ private Disposables() {
     }
 
     /**
-     * Construct a Disposable by wrapping a Runnable that is
-     * executed exactly once when the Disposable is disposed.
+     * Construct a {@code Disposable} by wrapping a {@link Runnable} that is
+     * executed exactly once when the {@code Disposable} is disposed.
      * @param run the Runnable to wrap
      * @return the new Disposable instance
      */
@@ -47,8 +47,8 @@ public static Disposable fromRunnable(@NonNull Runnable run) {
     }
 
     /**
-     * Construct a Disposable by wrapping a Action that is
-     * executed exactly once when the Disposable is disposed.
+     * Construct a {@code Disposable} by wrapping a {@link Action} that is
+     * executed exactly once when the {@code Disposable} is disposed.
      * @param run the Action to wrap
      * @return the new Disposable instance
      */
@@ -59,10 +59,13 @@ public static Disposable fromAction(@NonNull Action run) {
     }
 
     /**
-     * Construct a Disposable by wrapping a Future that is
-     * cancelled exactly once when the Disposable is disposed.
+     * Construct a {@code Disposable} by wrapping a {@link Future} that is
+     * cancelled exactly once when the {@code Disposable} is disposed.
+     * <p>
+     * The {@code Future} is cancelled with {@code mayInterruptIfRunning == true}.
      * @param future the Future to wrap
      * @return the new Disposable instance
+     * @see #fromFuture(Future, boolean)
      */
     @NonNull
     public static Disposable fromFuture(@NonNull Future<?> future) {
@@ -71,10 +74,10 @@ public static Disposable fromFuture(@NonNull Future<?> future) {
     }
 
     /**
-     * Construct a Disposable by wrapping a Future that is
-     * cancelled exactly once when the Disposable is disposed.
+     * Construct a {@code Disposable} by wrapping a {@link Future} that is
+     * cancelled exactly once when the {@code Disposable} is disposed.
      * @param future the Future to wrap
-     * @param allowInterrupt if true, the future cancel happens via Future.cancel(true)
+     * @param allowInterrupt if true, the future cancel happens via {@code Future.cancel(true)}
      * @return the new Disposable instance
      */
     @NonNull
@@ -84,8 +87,8 @@ public static Disposable fromFuture(@NonNull Future<?> future, boolean allowInte
     }
 
     /**
-     * Construct a Disposable by wrapping a Subscription that is
-     * cancelled exactly once when the Disposable is disposed.
+     * Construct a {@code Disposable} by wrapping a {@link Subscription} that is
+     * cancelled exactly once when the {@code Disposable} is disposed.
      * @param subscription the Runnable to wrap
      * @return the new Disposable instance
      */
@@ -96,17 +99,42 @@ public static Disposable fromSubscription(@NonNull Subscription subscription) {
     }
 
     /**
-     * Returns a new, non-disposed Disposable instance.
-     * @return a new, non-disposed Disposable instance
+     * Construct a {@code Disposable} by wrapping an {@link AutoCloseable} that is
+     * closed exactly once when the {@code Disposable} is disposed.
+     * @param autoCloseable the AutoCloseable to wrap
+     * @return the new Disposable instance
+     * @since 3.0.0
+     */
+    @NonNull
+    public static Disposable fromAutoCloseable(@NonNull AutoCloseable autoCloseable) {
+        Objects.requireNonNull(autoCloseable, "autoCloseable is null");
+        return new AutoCloseableDisposable(autoCloseable);
+    }
+
+    /**
+     * Construct an {@link AutoCloseable} by wrapping a {@code Disposable} that is
+     * disposed when the returned {@code AutoCloseable} is closed.
+     * @param disposable the Disposable instance
+     * @return the new AutoCloseable instance
+     * @since 3.0.0
+     */
+    @NonNull
+    public static AutoCloseable toAutoCloseable(@NonNull Disposable disposable) {
+        return disposable::dispose;
+    }
+
+    /**
+     * Returns a new, non-disposed {@code Disposable} instance.
+     * @return a new, non-disposed {@code Disposable} instance
      */
     @NonNull
     public static Disposable empty() {
         return fromRunnable(Functions.EMPTY_RUNNABLE);
     }
 
     /**
-     * Returns a disposed Disposable instance.
-     * @return a disposed Disposable instance
+     * Returns a shared, disposed {@code Disposable} instance.
+     * @return a shared, disposed {@code Disposable} instance
      */
     @NonNull
     public static Disposable disposed() {

src/main/java/io/reactivex/rxjava3/disposables/FutureDisposable.java

@@ -16,7 +16,7 @@
 import java.util.concurrent.atomic.AtomicReference;
 
 /**
- * A Disposable container that cancels a Future instance.
+ * A Disposable container that cancels a {@link Future} instance.
  */
 final class FutureDisposable extends AtomicReference<Future<?>> implements Disposable {
 

src/main/java/io/reactivex/rxjava3/disposables/RunnableDisposable.java

@@ -15,7 +15,7 @@
 import io.reactivex.rxjava3.annotations.NonNull;
 
 /**
- * A disposable container that manages a Runnable instance.
+ * A disposable container that manages a {@link Runnable} instance.
  */
 final class RunnableDisposable extends ReferenceDisposable<Runnable> {
 

src/test/java/io/reactivex/rxjava3/disposables/DisposablesTest.java

@@ -25,6 +25,7 @@
 import org.reactivestreams.Subscription;
 
 import io.reactivex.rxjava3.core.RxJavaTest;
+import io.reactivex.rxjava3.exceptions.TestException;
 import io.reactivex.rxjava3.functions.Action;
 import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
 import io.reactivex.rxjava3.plugins.RxJavaPlugins;
@@ -34,11 +35,19 @@ public class DisposablesTest extends RxJavaTest {
 
     @Test
     public void unsubscribeOnlyOnce() {
-        Runnable dispose = mock(Runnable.class);
-        Disposable subscription = Disposables.fromRunnable(dispose);
-        subscription.dispose();
-        subscription.dispose();
-        verify(dispose, times(1)).run();
+        Runnable run = mock(Runnable.class);
+
+        Disposable d = Disposables.fromRunnable(run);
+
+        assertTrue(d.toString(), d.toString().contains("RunnableDisposable(disposed=false, "));
+
+        d.dispose();
+        assertTrue(d.toString(), d.toString().contains("RunnableDisposable(disposed=true, "));
+
+        d.dispose();
+        assertTrue(d.toString(), d.toString().contains("RunnableDisposable(disposed=true, "));
+
+        verify(run, times(1)).run();
     }
 
     @Test
@@ -61,22 +70,20 @@ public void utilityClass() {
     }
 
     @Test
-    public void fromAction() {
-        class AtomicAction extends AtomicBoolean implements Action {
+    public void fromAction() throws Throwable {
+        Action action = mock(Action.class);
 
-            private static final long serialVersionUID = -1517510584253657229L;
+        Disposable d = Disposables.fromAction(action);
 
-            @Override
-            public void run() throws Exception {
-                set(true);
-            }
-        }
+        assertTrue(d.toString(), d.toString().contains("ActionDisposable(disposed=false, "));
 
-        AtomicAction aa = new AtomicAction();
+        d.dispose();
+        assertTrue(d.toString(), d.toString().contains("ActionDisposable(disposed=true, "));
 
-        Disposables.fromAction(aa).dispose();
+        d.dispose();
+        assertTrue(d.toString(), d.toString().contains("ActionDisposable(disposed=true, "));
 
-        assertTrue(aa.get());
+        verify(action, times(1)).run();
     }
 
     @Test
@@ -174,4 +181,76 @@ public void setOnceTwice() {
             RxJavaPlugins.reset();
         }
     }
+
+    @Test
+    public void fromAutoCloseable() {
+        AtomicInteger counter = new AtomicInteger();
+
+        AutoCloseable ac = () -> counter.getAndIncrement();
+
+        Disposable d = Disposables.fromAutoCloseable(ac);
+
+        assertFalse(d.isDisposed());
+        assertEquals(0, counter.get());
+        assertTrue(d.toString(), d.toString().contains("AutoCloseableDisposable(disposed=false, "));
+
+        d.dispose();
+
+        assertTrue(d.isDisposed());
+        assertEquals(1, counter.get());
+        assertTrue(d.toString(), d.toString().contains("AutoCloseableDisposable(disposed=true, "));
+
+        d.dispose();
+
+        assertTrue(d.isDisposed());
+        assertEquals(1, counter.get());
+        assertTrue(d.toString(), d.toString().contains("AutoCloseableDisposable(disposed=true, "));
+    }
+
+    @Test
+    public void fromAutoCloseableThrows() throws Throwable {
+        TestHelper.withErrorTracking(errors -> {
+            AutoCloseable ac = () -> { throw new TestException(); };
+
+            Disposable d = Disposables.fromAutoCloseable(ac);
+
+            assertFalse(d.isDisposed());
+
+            assertTrue(errors.isEmpty());
+
+            d.dispose();
+
+            assertTrue(d.isDisposed());
+            assertEquals(1, errors.size());
+
+            d.dispose();
+
+            assertTrue(d.isDisposed());
+            assertEquals(1, errors.size());
+
+            TestHelper.assertUndeliverable(errors, 0, TestException.class);
+        });
+    }
+
+    @Test
+    public void toAutoCloseable() throws Exception {
+        AtomicInteger counter = new AtomicInteger();
+
+        Disposable d = Disposables.fromAction(() -> counter.getAndIncrement());
+
+        AutoCloseable ac = Disposables.toAutoCloseable(d);
+
+        assertFalse(d.isDisposed());
+        assertEquals(0, counter.get());
+
+        ac.close();
+
+        assertTrue(d.isDisposed());
+        assertEquals(1, counter.get());
+
+        ac.close();
+
+        assertTrue(d.isDisposed());
+        assertEquals(1, counter.get());
+    }
 }