Separated Android code and core code into distinct Eclipse projects.

This should make it possible to develop the core in Eclipse without the ADT.

briar-android/src/net/sf/briar/android/AndroidExecutorImpl.java

@@ -0,0 +1,82 @@
+package net.sf.briar.android;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import net.sf.briar.api.android.AndroidExecutor;
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+
+import com.google.inject.Inject;
+
+class AndroidExecutorImpl implements AndroidExecutor {
+
+	private static final int SHUTDOWN = 0, RUN = 1;
+
+	private final Runnable loop;
+	private final AtomicBoolean started = new AtomicBoolean(false);
+	private final CountDownLatch startLatch = new CountDownLatch(1);
+
+	private volatile Handler handler = null;
+
+	@Inject
+	AndroidExecutorImpl() {
+		loop = new Runnable() {
+			public void run() {
+				Looper.prepare();
+				handler = new FutureTaskHandler();
+				startLatch.countDown();
+				Looper.loop();
+			}
+		};
+	}
+
+	private void startIfNecessary() {
+		if(started.getAndSet(true)) return;
+		new Thread(loop, "AndroidExecutor").start();
+		try {
+			startLatch.await();
+		} catch(InterruptedException e) {
+			Thread.currentThread().interrupt();
+		}
+	}
+
+	public <V> V run(Callable<V> c) throws InterruptedException,
+	ExecutionException {
+		startIfNecessary();
+		Future<V> f = new FutureTask<V>(c);
+		Message m = Message.obtain(handler, RUN, f);
+		handler.sendMessage(m);
+		return f.get();
+	}
+
+	public void shutdown() {
+		if(handler != null) {
+			Message m = Message.obtain(handler, SHUTDOWN);
+			handler.sendMessage(m);
+		}
+	}
+
+	private static class FutureTaskHandler extends Handler {
+
+		@Override
+		public void handleMessage(Message m) {
+			switch(m.what) {
+			case SHUTDOWN:
+				Looper.myLooper().quit();
+				break;
+			case RUN:
+				((FutureTask<?>) m.obj).run();
+				break;
+			default:
+				throw new IllegalArgumentException();
+			}
+		}
+	}
+}
+