首次提交

nebula-sdk/src/main/java/com/android/download/AppExecutors.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2017 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.download;
+
+import android.os.Handler;
+import android.os.Looper;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.Executors;
+
+/**
+ * Global executor pools for the whole application.
+ * <p>
+ * Grouping tasks like this avoids the effects of task starvation (e.g. disk reads don't wait behind
+ * webservice requests).
+ */
+public class AppExecutors {
+    private static AppExecutors appExecutors;
+    private final Executor diskIO;
+
+    private final Executor networkIO;
+
+    private final Executor mainThread;
+
+    private AppExecutors(Executor diskIO, Executor networkIO, Executor mainThread) {
+        this.diskIO = diskIO;
+        this.networkIO = networkIO;
+        this.mainThread = mainThread;
+    }
+
+    private AppExecutors() {
+        this(Executors.newSingleThreadExecutor(), Executors.newFixedThreadPool(3),
+                new MainThreadExecutor());
+    }
+
+    public static AppExecutors getAppExecutors() {
+        if (appExecutors == null)
+            return new AppExecutors();
+        else
+            return appExecutors;
+    }
+
+    public Executor diskIO() {
+        return diskIO;
+    }
+
+    public Executor networkIO() {
+        return networkIO;
+    }
+
+    public Executor mainThread() {
+        return mainThread;
+    }
+
+    private static class MainThreadExecutor implements Executor {
+        private Handler mainThreadHandler = new Handler(Looper.getMainLooper());
+
+        @Override
+        public void execute(Runnable command) {
+            mainThreadHandler.post(command);
+        }
+    }
+}