Semi-encapsulated the core/api dependency graphs and created a proper structure to load eager singletons

briar-android/src/org/briarproject/system/AndroidExecutorImpl.java

@@ -0,0 +1,48 @@
+package org.briarproject.system;
+
+import android.app.Application;
+import android.content.Context;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+
+import org.briarproject.api.android.PlatformExecutor;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+
+import javax.inject.Inject;
+
+class AndroidExecutorImpl implements PlatformExecutor {
+
+	private final Handler handler;
+
+	AndroidExecutorImpl(Application app) {
+		Context ctx = app.getApplicationContext();
+		handler = new FutureTaskHandler(ctx.getMainLooper());
+	}
+
+	public <V> Future<V> submit(Callable<V> c) {
+		Future<V> f = new FutureTask<V>(c);
+		handler.sendMessage(Message.obtain(handler, 0, f));
+		return f;
+	}
+
+	public void execute(Runnable r) {
+		handler.post(r);
+	}
+
+	private static class FutureTaskHandler extends Handler {
+
+		private FutureTaskHandler(Looper looper) {
+			super(looper);
+		}
+
+		@Override
+		public void handleMessage(Message m) {
+			((FutureTask<?>) m.obj).run();
+		}
+	}
+}
+