适用于 Java/Android 的 TPL 等效项

Question

I'm curious to know if there's something similar to the Task Parallel Library from C# in Java and/or the Android SDK. Coming from a C# background, we're taught that making a new thread is a relatively heavyweight operation, and are instructed to use the threadpool, or more recently, Tasks.

So in my mind, the level of abstraction that Tasks bring would be ideal... is there anything like that, or even the threadpool? or does it all just involve making a new Thread or making my own threadpool

Answer 1

Sure it does. You can read more about it here: Executors

Also, you could overview the whole concurrency topic at the same page: Concurrency

Answer 2

See http://developer.android.com/reference/java/util/concurrent/package-summary.html for threadpool info.

Answer 3

I think that the java.util.concurrent package has most of the classes/functionality you are looking for.

Specifically, take a look at these:

1. ThreadPoolExecutor
2. Executors
3. CompletionService

Answer 4

According to Java developers, Java concurrency programming should be moving towards the usage of the new Concurrency API.

Check: http://download.oracle.com/javase/1.5.0/docs/guide/concurrency/index.html

Answer 5

Android has support for Javas concurrency library but you should look into AsyncTask which supports running operations on both on the UI thread and in the background.

Here is an a short example of a task:

private class CharCountTask extends AsyncTask<String, Integer, Long> {
  protected Long doInBackground(String... in) {
    long result = 0;
    for(int i=0,n=in.length; i<n; i++) {
      result += in[i].length();
      publishProgress((int) (i / (double) count) * 100);
    }
    return result;
  }

  protected void onProgressUpdate(Integer... progress) {
    // update progress here
    updateProgressBar(progress[0]);
  }

  protected void onPostExecute(Long result) {
    // update the UI here
    setTotalChars(result);
  }
}

To use it:

new CharCountTask().execute("first", "second", "third");

Answer 6

Look at the Task4Java framework at https://github.com/dtag-dbu/task4java/ .

This framework was build on standard Java libraries and runs also on Android. Currently we are creating a sample application to show the power of this framework.