Merge "Create UI lifecycle aware executor factory." into main

src/com/android/settings/fuelgauge/utils/LifecycleAwareExecutorFactory.kt

@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * 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.android.settings.fuelgauge.utils
+
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+
+/**
+ *  The factory class to create executors which could bind with an UI page lifecycle and shutdown
+ *  automatically when onStop() method was invoked.
+ *
+ *  NOTE: Creating an executor from an UI page MUST set the lifecycle. Only non-UI jobs can set
+ *  the lifecycle to null.
+ */
+object LifecycleAwareExecutorFactory {
+
+    fun newSingleThreadExecutor(lifecycle: Lifecycle?): ExecutorService {
+        return Executors.newSingleThreadExecutor().also { executor ->
+            executor.autoShutdown(lifecycle)
+        }
+    }
+
+    fun newFixedThreadPool(lifecycle: Lifecycle?, nThreads: Int): ExecutorService {
+        return Executors.newFixedThreadPool(nThreads).also { executor ->
+            executor.autoShutdown(lifecycle)
+        }
+    }
+
+    fun newCachedThreadPool(lifecycle: Lifecycle?): ExecutorService {
+        return Executors.newCachedThreadPool().also { executor ->
+            executor.autoShutdown(lifecycle)
+        }
+    }
+
+    private fun ExecutorService.autoShutdown(lifecycle: Lifecycle?) {
+        if (lifecycle == null) {
+            return
+        }
+
+        val observer = object : DefaultLifecycleObserver {
+            override fun onStop(owner: LifecycleOwner) {
+                this@autoShutdown.shutdown()
+                owner.lifecycle.removeObserver(this)
+            }
+        }
+        lifecycle.addObserver(observer)
+    }
+}

tests/robotests/src/com/android/settings/fuelgauge/utils/LifecycleAwareExecutorFactoryTest.kt

@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * 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.android.settings.fuelgauge.utils
+
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.Lifecycle.State
+import androidx.lifecycle.LifecycleObserver
+import androidx.lifecycle.LifecycleOwner
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.util.concurrent.CountDownLatch
+
+@RunWith(AndroidJUnit4::class)
+class LifecycleAwareExecutorFactoryTest {
+    private val lifecycle = FakeLifecycle(State.CREATED)
+    private val lifecycleOwner = FakeLifecycleOwner(lifecycle)
+
+    @Test
+    fun newSingleThreadExecutor_addObserver() {
+        LifecycleAwareExecutorFactory.newSingleThreadExecutor(lifecycle)
+
+        assertThat(lifecycle.observerList).hasSize(1)
+    }
+
+    @Test
+    fun newSingleThreadExecutor_autoShutdown() {
+        val executorRunningBlocker = CountDownLatch(1)
+        val executor = LifecycleAwareExecutorFactory.newSingleThreadExecutor(lifecycle)
+
+        executor.submit {
+            executorRunningBlocker.await()
+        }
+        lifecycle.observerList[0].onStop(lifecycleOwner)
+
+        assertThat(executor.isShutdown).isTrue()
+        assertThat(lifecycle.observerList).isEmpty()
+    }
+
+    @Test
+    fun newFixedThreadPool_addObserver() {
+        LifecycleAwareExecutorFactory.newFixedThreadPool(lifecycle, nThreads = 6)
+
+        assertThat(lifecycle.observerList).hasSize(1)
+    }
+
+    @Test
+    fun newFixedThreadPool_autoShutdown() {
+        val executorRunningBlocker = CountDownLatch(1)
+        val executor = LifecycleAwareExecutorFactory.newFixedThreadPool(lifecycle, nThreads = 8)
+
+        executor.submit {
+            executorRunningBlocker.await()
+        }
+        lifecycle.observerList[0].onStop(lifecycleOwner)
+
+        assertThat(executor.isShutdown).isTrue()
+        assertThat(lifecycle.observerList).isEmpty()
+    }
+
+    @Test
+    fun newCachedThreadPool_addObserver() {
+        LifecycleAwareExecutorFactory.newCachedThreadPool(lifecycle)
+
+        assertThat(lifecycle.observerList).hasSize(1)
+    }
+
+    @Test
+    fun newCachedThreadPool_autoShutdown() {
+        val executorRunningBlocker = CountDownLatch(1)
+        val executor = LifecycleAwareExecutorFactory.newCachedThreadPool(lifecycle)
+
+        executor.submit {
+            executorRunningBlocker.await()
+        }
+        lifecycle.observerList[0].onStop(lifecycleOwner)
+
+        assertThat(executor.isShutdown).isTrue()
+        assertThat(lifecycle.observerList).isEmpty()
+    }
+
+    private class FakeLifecycle(override val currentState: State) : Lifecycle() {
+        val observerList = mutableListOf<DefaultLifecycleObserver>()
+
+        override fun addObserver(observer: LifecycleObserver) {
+            if (observer is DefaultLifecycleObserver) {
+                observerList.add(observer)
+            }
+        }
+
+        override fun removeObserver(observer: LifecycleObserver) {
+            if (observer is DefaultLifecycleObserver) {
+                observerList.remove(observer)
+            }
+        }
+    }
+
+    private class FakeLifecycleOwner(override val lifecycle: Lifecycle) : LifecycleOwner
+}