Move ListenableFutureTask up to parent.

src/org/thoughtcrime/securesms/util/FutureTaskListener.java

@@ -0,0 +1,22 @@
+/**
+ * Copyright (C) 2014 Open Whisper Systems
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.thoughtcrime.securesms.util;
+
+public interface FutureTaskListener<V> {
+  public void onSuccess(V result);
+  public void onFailure(Throwable error);
+}

src/org/thoughtcrime/securesms/util/ListenableFutureTask.java

@@ -0,0 +1,67 @@
+/**
+ * Copyright (C) 2014 Open Whisper Systems
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.thoughtcrime.securesms.util;
+
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.FutureTask;
+
+public class ListenableFutureTask<V> extends FutureTask<V> {
+
+  private final List<FutureTaskListener<V>> listeners = new LinkedList<>();
+
+  public ListenableFutureTask(Callable<V> callable) {
+    super(callable);
+  }
+
+  public synchronized void addListener(FutureTaskListener<V> listener) {
+    if (this.isDone()) {
+      callback(listener);
+    } else {
+      this.listeners.add(listener);
+    }
+  }
+
+  public synchronized void removeListener(FutureTaskListener<V> listener) {
+    this.listeners.remove(listener);
+  }
+
+  @Override
+  protected synchronized void done() {
+    callback();
+  }
+
+  private void callback() {
+    for (FutureTaskListener<V> listener : listeners) {
+      callback(listener);
+    }
+  }
+
+  private void callback(FutureTaskListener<V> listener) {
+    if (listener != null) {
+      try {
+        listener.onSuccess(get());
+      } catch (InterruptedException e) {
+        throw new AssertionError(e);
+      } catch (ExecutionException e) {
+        listener.onFailure(e);
+      }
+    }
+  }
+}