Add bolts tasks to this library

bolts-tasks/build.gradle

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+// Copyright (c) Facebook, Inc. and its affiliates.
+//
+// This source code is licensed under the MIT license found in the/
+// LICENSE file in the root directory of this source tree.
+
+apply plugin: 'java'
+
+configurations {
+    provided
+}
+
+sourceSets {
+    main {
+        compileClasspath += configurations.provided
+    }
+}
+
+dependencies {
+    provided 'com.google.android:android:4.1.1.4'
+    testImplementation 'junit:junit:4.12'
+}
+
+
+javadoc.options.addStringOption('Xdoclint:none', '-quiet')
+
+task sourcesJar(type: Jar) {
+    classifier = 'sources'
+    from sourceSets.main.allJava
+}
+
+task javadocJar (type: Jar, dependsOn: javadoc) {
+    classifier = 'javadoc'
+    from javadoc.destinationDir
+}
+
+artifacts {
+    archives sourcesJar
+    archives javadocJar
+}
+
+//endregion
+
+//region Code Coverage
+
+apply plugin: 'jacoco'
+
+jacoco {
+    toolVersion = '0.7.1.201405082137'
+}
+
+jacocoTestReport {
+    group = "Reporting"
+    description = "Generate Jacoco coverage reports after running tests."
+    reports {
+        xml.enabled true
+        html.enabled true
+    }
+}
+
+//endregion

bolts-tasks/src/main/java/bolts/AggregateException.java

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+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+package bolts;
+
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Aggregates multiple {@code Throwable}s that may be thrown in the process of a task's execution.
+ *
+ * @see Task#whenAll(java.util.Collection)
+ */
+public class AggregateException extends Exception {
+    private static final long serialVersionUID = 1L;
+
+    private static final String DEFAULT_MESSAGE = "There were multiple errors.";
+
+    private List<Throwable> innerThrowables;
+
+    /**
+     * Constructs a new {@code AggregateException} with the current stack trace, the specified detail
+     * message and with references to the inner throwables that are the cause of this exception.
+     *
+     * @param detailMessage   The detail message for this exception.
+     * @param innerThrowables The exceptions that are the cause of the current exception.
+     */
+    public AggregateException(String detailMessage, Throwable[] innerThrowables) {
+        this(detailMessage, Arrays.asList(innerThrowables));
+    }
+
+
+    /**
+     * Constructs a new {@code AggregateException} with the current stack trace, the specified detail
+     * message and with references to the inner throwables that are the cause of this exception.
+     *
+     * @param detailMessage   The detail message for this exception.
+     * @param innerThrowables The exceptions that are the cause of the current exception.
+     */
+    public AggregateException(String detailMessage, List<? extends Throwable> innerThrowables) {
+        super(detailMessage,
+                innerThrowables != null && innerThrowables.size() > 0 ? innerThrowables.get(0) : null);
+        this.innerThrowables = Collections.unmodifiableList(innerThrowables);
+    }
+
+    /**
+     * Constructs a new {@code AggregateException} with the current stack trace and with references to
+     * the inner throwables that are the cause of this exception.
+     *
+     * @param innerThrowables The exceptions that are the cause of the current exception.
+     */
+    public AggregateException(List<? extends Throwable> innerThrowables) {
+        this(DEFAULT_MESSAGE, innerThrowables);
+    }
+
+    /**
+     * Returns a read-only {@link List} of the {@link Throwable} instances that caused the current
+     * exception.
+     */
+    public List<Throwable> getInnerThrowables() {
+        return innerThrowables;
+    }
+
+    @Override
+    public void printStackTrace(PrintStream err) {
+        super.printStackTrace(err);
+
+        int currentIndex = -1;
+        for (Throwable throwable : innerThrowables) {
+            err.append("\n");
+            err.append("  Inner throwable #");
+            err.append(Integer.toString(++currentIndex));
+            err.append(": ");
+            throwable.printStackTrace(err);
+            err.append("\n");
+        }
+    }
+
+    @Override
+    public void printStackTrace(PrintWriter err) {
+        super.printStackTrace(err);
+
+        int currentIndex = -1;
+        for (Throwable throwable : innerThrowables) {
+            err.append("\n");
+            err.append("  Inner throwable #");
+            err.append(Integer.toString(++currentIndex));
+            err.append(": ");
+            throwable.printStackTrace(err);
+            err.append("\n");
+        }
+    }
+
+    /**
+     * @deprecated Please use {@link #getInnerThrowables()} instead.
+     */
+    @Deprecated
+    public List<Exception> getErrors() {
+        List<Exception> errors = new ArrayList<Exception>();
+        if (innerThrowables == null) {
+            return errors;
+        }
+
+        for (Throwable cause : innerThrowables) {
+            if (cause instanceof Exception) {
+                errors.add((Exception) cause);
+            } else {
+                errors.add(new Exception(cause));
+            }
+        }
+        return errors;
+    }
+
+    /**
+     * @deprecated Please use {@link #getInnerThrowables()} instead.
+     */
+    @Deprecated
+    public Throwable[] getCauses() {
+        return innerThrowables.toArray(new Throwable[innerThrowables.size()]);
+    }
+
+}

bolts-tasks/src/main/java/bolts/AndroidExecutors.java

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+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+package bolts;
+
+import android.annotation.SuppressLint;
+import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * This was created because the helper methods in {@link java.util.concurrent.Executors} do not work
+ * as people would normally expect.
+ * <p>
+ * Normally, you would think that a cached thread pool would create new threads when necessary,
+ * queue them when the pool is full, and kill threads when they've been inactive for a certain
+ * period of time. This is not how {@link java.util.concurrent.Executors#newCachedThreadPool()}
+ * works.
+ * <p>
+ * Instead, {@link java.util.concurrent.Executors#newCachedThreadPool()} executes all tasks on
+ * a new or cached thread immediately because corePoolSize is 0, SynchronousQueue is a queue with
+ * size 0 and maxPoolSize is Integer.MAX_VALUE. This is dangerous because it can create an unchecked
+ * amount of threads.
+ */
+/* package */ final class AndroidExecutors {
+
+    private static final AndroidExecutors INSTANCE = new AndroidExecutors();
+
+    private final Executor uiThread;
+
+    private AndroidExecutors() {
+        uiThread = new UIThreadExecutor();
+    }
+
+    /**
+     * Nexus 5: Quad-Core
+     * Moto X: Dual-Core
+     * <p>
+     * AsyncTask:
+     * CORE_POOL_SIZE = CPU_COUNT + 1
+     * MAX_POOL_SIZE = CPU_COUNT * 2 + 1
+     * <p>
+     * https://github.com/android/platform_frameworks_base/commit/719c44e03b97e850a46136ba336d729f5fbd1f47
+     */
+    private static final int CPU_COUNT = Runtime.getRuntime().availableProcessors();
+    /* package */ static final int CORE_POOL_SIZE = CPU_COUNT + 1;
+    /* package */ static final int MAX_POOL_SIZE = CPU_COUNT * 2 + 1;
+    /* package */ static final long KEEP_ALIVE_TIME = 1L;
+
+    /**
+     * Creates a proper Cached Thread Pool. Tasks will reuse cached threads if available
+     * or create new threads until the core pool is full. tasks will then be queued. If an
+     * task cannot be queued, a new thread will be created unless this would exceed max pool
+     * size, then the task will be rejected. Threads will time out after 1 second.
+     * <p>
+     * Core thread timeout is only available on android-9+.
+     *
+     * @return the newly created thread pool
+     */
+    public static ExecutorService newCachedThreadPool() {
+        ThreadPoolExecutor executor = new ThreadPoolExecutor(
+                CORE_POOL_SIZE,
+                MAX_POOL_SIZE,
+                KEEP_ALIVE_TIME, TimeUnit.SECONDS,
+                new LinkedBlockingQueue<Runnable>());
+
+        allowCoreThreadTimeout(executor, true);
+
+        return executor;
+    }
+
+    /**
+     * Creates a proper Cached Thread Pool. Tasks will reuse cached threads if available
+     * or create new threads until the core pool is full. tasks will then be queued. If an
+     * task cannot be queued, a new thread will be created unless this would exceed max pool
+     * size, then the task will be rejected. Threads will time out after 1 second.
+     * <p>
+     * Core thread timeout is only available on android-9+.
+     *
+     * @param threadFactory the factory to use when creating new threads
+     * @return the newly created thread pool
+     */
+    public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory) {
+        ThreadPoolExecutor executor = new ThreadPoolExecutor(
+                CORE_POOL_SIZE,
+                MAX_POOL_SIZE,
+                KEEP_ALIVE_TIME, TimeUnit.SECONDS,
+                new LinkedBlockingQueue<Runnable>(),
+                threadFactory);
+
+        allowCoreThreadTimeout(executor, true);
+
+        return executor;
+    }
+
+    /**
+     * Compatibility helper function for
+     * {@link java.util.concurrent.ThreadPoolExecutor#allowCoreThreadTimeOut(boolean)}
+     * <p>
+     * Only available on android-9+.
+     *
+     * @param executor the {@link java.util.concurrent.ThreadPoolExecutor}
+     * @param value    true if should time out, else false
+     */
+    @SuppressLint("NewApi")
+    public static void allowCoreThreadTimeout(ThreadPoolExecutor executor, boolean value) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
+            executor.allowCoreThreadTimeOut(value);
+        }
+    }
+
+    /**
+     * An {@link java.util.concurrent.Executor} that executes tasks on the UI thread.
+     */
+    public static Executor uiThread() {
+        return INSTANCE.uiThread;
+    }
+
+    /**
+     * An {@link java.util.concurrent.Executor} that runs tasks on the UI thread.
+     */
+    private static class UIThreadExecutor implements Executor {
+        @Override
+        public void execute(Runnable command) {
+            new Handler(Looper.getMainLooper()).post(command);
+        }
+    }
+}