ListenableFutureTask.java

package org.whispersystems.textsecure.util;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;

public class ListenableFutureTask<V> extends FutureTask<V> {

//  private WeakReference<FutureTaskListener<V>> listener;
  private FutureTaskListener<V> listener;

  public ListenableFutureTask(Callable<V> callable, FutureTaskListener<V> listener) {
    super(callable);
    this.listener = listener;
//    if (listener == null) {
//      this.listener = null;
//    } else {
//      this.listener = new WeakReference<FutureTaskListener<V>>(listener);
//    }
  }

  public synchronized void setListener(FutureTaskListener<V> listener) {
//    if (listener != null) this.listener = new WeakReference<FutureTaskListener<V>>(listener);
//    else                  this.listener = null;
    this.listener = listener;

    if (this.isDone()) {
      callback();
    }
  }

  @Override
  protected synchronized void done() {
    callback();
  }

  private void callback() {
    if (this.listener != null) {
      FutureTaskListener<V> nestedListener = this.listener;
//      FutureTaskListener<V> nestedListener = this.listener.get();
      if (nestedListener != null) {
        try {
          nestedListener.onSuccess(get());
        } catch (ExecutionException ee) {
          nestedListener.onFailure(ee);
        } catch (InterruptedException e) {
          throw new AssertionError(e);
        }
      }
    }
  }
}