RxLifecycle interop module (#118)

* RX lifecycle interop module added for autodipose

* Added pom artifact

* Renamed package, fixed javadoc and addressed other review comments

* Fixed lifecycle everywhere and moved rxlifecycle to misc in dependencies.gradle

* Fixed javadoc

* Renamed RXLifecycle to RxLifecycle and method name fix

* Renamed depdencies in dependency.gradle and removed class from javadoc

* Renamed methods in RXLifecycle to from() for consistency

* Added javadoc for individual methods

* Removed double space

* Fixed checkstyle for test

* fixed exception name

* API replaced with implementation to avoid transitive compile time dependencies

* Reverted the incorrect api

* Added more javadoc in package-info.java and license header to all the files

* Fixed javadoc

autodispose-rxlifecycle/build.gradle

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2017. Uber Technologies
+ *
+ * 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.
+ */
+
+buildscript {
+    repositories {
+        jcenter()
+        maven { url deps.build.repositories.plugins }
+    }
+    dependencies {
+        classpath deps.build.gradlePlugins.apt
+        classpath deps.build.gradlePlugins.errorProne
+    }
+}
+
+apply plugin: 'java-library'
+apply plugin: 'net.ltgt.apt'
+apply plugin: 'net.ltgt.errorprone'
+
+sourceCompatibility = "1.7"
+targetCompatibility = "1.7"
+
+test {
+    testLogging.showStandardStreams = true
+}
+
+dependencies {
+    apt deps.build.nullAway
+    testApt deps.build.nullAway
+
+    compile project(':autodispose')
+    compile deps.misc.rxlifecycle
+    compileOnly deps.misc.errorProneAnnotations
+    compileOnly deps.misc.javaxExtras
+
+    errorprone deps.build.checkerFramework
+    errorprone deps.build.errorProne
+
+    testCompile project(':test-utils')
+}
+
+tasks.withType(JavaCompile) {
+    options.compilerArgs += ["-Xep:NullAway:ERROR", "-XepOpt:NullAway:AnnotatedPackages=com.uber"]
+}
+
+apply from: rootProject.file('gradle/gradle-mvn-push.gradle')

autodispose-rxlifecycle/gradle.properties

@@ -0,0 +1,19 @@
+#
+# Copyright (C) 2017. Uber Technologies
+#
+# 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.
+#
+
+POM_NAME=AutoDispose (RxLifecycle Interop)
+POM_ARTIFACT_ID=autodispose-rxlifecycle
+POM_PACKAGING=jar

autodispose-rxlifecycle/src/main/java/com/ubercab/autodispose/rxlifecycle/RxLifecycleInterop.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2017. Uber Technologies
+ *
+ * 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 com.ubercab.autodispose.rxlifecycle;
+
+import com.trello.rxlifecycle2.LifecycleProvider;
+import com.trello.rxlifecycle2.OutsideLifecycleException;
+import com.uber.autodispose.AutoDispose.ScopeHandler;
+import com.uber.autodispose.LifecycleEndedException;
+import com.uber.autodispose.ScopeProvider;
+import io.reactivex.Maybe;
+
+/**
+ * Interop for RxLifecycle. It provides static utility methods to convert {@link
+ * LifecycleProvider} to {@link ScopeProvider}.
+ *
+ * <p>There are several static utility converter
+ * methods such as {@link #from(LifecycleProvider)} for {@link
+ * LifecycleProvider#bindToLifecycle()} and {@link #from(LifecycleProvider, Object)} for
+ * {@link LifecycleProvider#bindUntilEvent(Object)}.
+ * <p>
+ *
+ * <em>Note:</em> RxLifecycle treats the {@link OutsideLifecycleException}
+ * as normal terminal event. There is no mapping to {@link LifecycleEndedException} and in such
+ * cases the stream is normally disposed.
+ */
+public final class RxLifecycleInterop {
+
+  private RxLifecycleInterop() {
+    throw new AssertionError("No Instances");
+  }
+
+  private static final Object DEFAULT_THROWAWAY_OBJECT = new Object();
+
+  /**
+   * Converter for transforming {@link LifecycleProvider} to {@link ScopeProvider}.
+   * It disposes the source when the next reasonable event occurs.
+   * <p>
+   * Example usage:
+   * <pre><code>
+   *   Observable.just(1)
+   *        .to(RxLifecycleInterop.from(lifecycleProvider))
+   *        .subscribe(...)
+   * </code></pre>
+   *
+   * @param <E> the lifecycle event.
+   * @param provider the {@link LifecycleProvider} for RxLifecycle.
+   * @return a {@link ScopeHandler} to create AutoDisposing transformation
+   */
+  public static <E> ScopeProvider from(final LifecycleProvider<E> provider) {
+    return new ScopeProvider() {
+      @Override public Maybe<?> requestScope() {
+        return provider.lifecycle()
+            .compose(provider.bindToLifecycle())
+            .ignoreElements()
+            .toMaybe()
+            .defaultIfEmpty(DEFAULT_THROWAWAY_OBJECT);
+      }
+    };
+  }
+
+  /**
+   * Converter for transforming {@link LifecycleProvider} to {@link ScopeProvider}.
+   * It disposes the source when a specific event occurs.
+   * <p>
+   * Example usage:
+   * <pre><code>
+   *   Observable.just(1)
+   *        .to(RxLifecycleInterop.from(lifecycleProvider, event))
+   *        .subscribe(...)
+   * </code></pre>
+   *
+   * @param <E> the lifecycle event.
+   * @param provider the {@link LifecycleProvider} for RxLifecycle.
+   * @param event the event at which the source is disposed.
+   * @return a {@link ScopeHandler} to create AutoDisposing transformation
+   */
+  public static <E> ScopeProvider from(final LifecycleProvider<E> provider, final E event) {
+    return new ScopeProvider() {
+      @Override public Maybe<?> requestScope() {
+        return provider.lifecycle()
+            .compose(provider.bindUntilEvent(event))
+            .ignoreElements()
+            .toMaybe()
+            .defaultIfEmpty(DEFAULT_THROWAWAY_OBJECT);
+      }
+    };
+  }
+}

autodispose-rxlifecycle/src/main/java/com/ubercab/autodispose/rxlifecycle/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2017. Uber Technologies
+ *
+ * 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.
+ */
+
+/**
+ * AutoDispose extensions for interop with RxLifecycle. This namely supports
+ * {@link com.trello.rxlifecycle2.LifecycleProvider}.
+ */
+@com.uber.javaxextras.FieldsMethodsAndParametersAreNonNullByDefault
+package com.ubercab.autodispose.rxlifecycle;
+

autodispose-rxlifecycle/src/test/java/com/ubercab/autodispose/rxlifecycle/RxLifecycleInteropTest.java

@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2017. Uber Technologies
+ *
+ * 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 com.ubercab.autodispose.rxlifecycle;
+
+import com.uber.autodispose.AutoDispose;
+import com.uber.autodispose.test.RecordingObserver;
+import io.reactivex.disposables.Disposable;
+import io.reactivex.observers.TestObserver;
+import io.reactivex.subjects.PublishSubject;
+import org.junit.Test;
+
+import static com.google.common.truth.Truth.assertThat;
+
+public class RxLifecycleInteropTest {
+
+  private static final RecordingObserver.Logger LOGGER = new RecordingObserver.Logger() {
+    @Override public void log(String message) {
+      System.out.println(RxLifecycleInteropTest.class.getSimpleName() + ": " + message);
+    }
+  };
+
+  private TestLifecycleProvider lifecycleProvider = new TestLifecycleProvider();
+
+  @Test
+  public void bindLifecycle_normalTermination_completeTheStream() {
+    lifecycleProvider.emitCreate();
+    TestObserver<Integer> o = new TestObserver<>();
+    PublishSubject<Integer> source = PublishSubject.create();
+    Disposable d = source.to(AutoDispose.with(
+        RxLifecycleInterop.from(lifecycleProvider)).<Integer>forObservable())
+        .subscribeWith(o);
+    o.assertSubscribed();
+
+    assertThat(source.hasObservers()).isTrue();
+
+    source.onNext(1);
+    o.assertValue(1);
+
+    source.onNext(2);
+    source.onComplete();
+    o.assertValues(1, 2);
+    o.assertComplete();
+    assertThat(d.isDisposed()).isFalse();   // Because it completed normally, was not disposed.
+    assertThat(source.hasObservers()).isFalse();
+  }
+
+  @Test
+  public void bindLifecycle_normalTermination_unsubscribe() {
+    lifecycleProvider.emitCreate();
+    RecordingObserver<Integer> o = new RecordingObserver<>(LOGGER);
+    PublishSubject<Integer> source = PublishSubject.create();
+    source.to(AutoDispose.with(
+        RxLifecycleInterop.from(lifecycleProvider)).<Integer>forObservable())
+        .subscribe(o);
+    o.takeSubscribe();
+
+    assertThat(source.hasObservers()).isTrue();
+
+    source.onNext(1);
+    assertThat(o.takeNext()).isEqualTo(1);
+
+    lifecycleProvider.emitDestroy();
+    source.onNext(2);
+    o.assertNoMoreEvents();
+    assertThat(source.hasObservers()).isFalse();
+  }
+
+  @Test
+  public void bindLifecycle_outsideLifecycleBound_unsubscribe() {
+    lifecycleProvider.emitCreate();
+    RecordingObserver<Integer> o = new RecordingObserver<>(LOGGER);
+    PublishSubject<Integer> source = PublishSubject.create();
+    lifecycleProvider.emitDestroy();
+    source
+        .to(AutoDispose.with(
+            RxLifecycleInterop.from(lifecycleProvider)).<Integer>forObservable())
+        .subscribe(o);
+
+    o.takeSubscribe();
+
+    source.onNext(2);
+    o.assertNoMoreEvents();
+    assertThat(
+        source.hasObservers()).isFalse(); // Because RxLifecycle
+    // treats OutsideLifecycleException as terminal event.
+  }
+
+  @Test
+  public void bindUntilEvent_normalTermination_completeTheStream() {
+    lifecycleProvider.emitCreate();
+    TestObserver<Integer> o = new TestObserver<>();
+    PublishSubject<Integer> source = PublishSubject.create();
+    Disposable d = source.to(AutoDispose.with(RxLifecycleInterop.from(
+        lifecycleProvider,
+        TestLifecycleProvider.Event.DESTROY)).<Integer>forObservable())
+        .subscribeWith(o);
+    o.assertSubscribed();
+
+    assertThat(source.hasObservers()).isTrue();
+
+    source.onNext(1);
+    o.assertValue(1);
+
+    source.onNext(2);
+    source.onComplete();
+    o.assertValues(1, 2);
+    o.assertComplete();
+    assertThat(d.isDisposed()).isFalse();   // Because it completed normally, was not disposed.
+    assertThat(source.hasObservers()).isFalse();
+  }
+
+  @Test
+  public void bindUntilEvent_interruptedTermination_unsubscribe() {
+    lifecycleProvider.emitCreate();
+    RecordingObserver<Integer> o = new RecordingObserver<>(LOGGER);
+    PublishSubject<Integer> source = PublishSubject.create();
+    source.to(AutoDispose.with(RxLifecycleInterop.from(lifecycleProvider,
+        TestLifecycleProvider.Event.DESTROY)).<Integer>forObservable())
+        .subscribe(o);
+    o.takeSubscribe();
+
+    assertThat(source.hasObservers()).isTrue();
+
+    source.onNext(1);
+    assertThat(o.takeNext()).isEqualTo(1);
+
+    lifecycleProvider.emitDestroy();
+    source.onNext(2);
+    o.assertNoMoreEvents();
+    assertThat(source.hasObservers()).isFalse();
+  }
+}