briar/briar-android/src/org/briarproject/plugins/tcp/AndroidLanTcpPlugin.java

package org.briarproject.plugins.tcp;

import static android.content.Context.CONNECTIVITY_SERVICE;
import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
import static android.net.ConnectivityManager.TYPE_WIFI;

import java.util.concurrent.Executor;
import java.util.logging.Logger;

import org.briarproject.api.plugins.duplex.DuplexPluginCallback;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

class AndroidLanTcpPlugin extends LanTcpPlugin {

	private static final Logger LOG =
			Logger.getLogger(AndroidLanTcpPlugin.class.getName());

	private final Context appContext;

	private volatile BroadcastReceiver networkStateReceiver = null;

	AndroidLanTcpPlugin(Executor ioExecutor, Context appContext,
			DuplexPluginCallback callback, int maxFrameLength, long maxLatency,
			long pollingInterval) {
		super(ioExecutor, callback, maxFrameLength, maxLatency,
				pollingInterval);
		this.appContext = appContext;
	}

	@Override
	public boolean start() {
		running = true;
		// Register to receive network status events
		networkStateReceiver = new NetworkStateReceiver();
		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
		appContext.registerReceiver(networkStateReceiver, filter);
		return true;
	}

	@Override
	public void stop() {
		running = false;
		if(networkStateReceiver != null)
			appContext.unregisterReceiver(networkStateReceiver);
		tryToClose(socket);
	}

	private class NetworkStateReceiver extends BroadcastReceiver {

		@Override
		public void onReceive(Context ctx, Intent i) {
			if(!running) return;
			Object o = ctx.getSystemService(CONNECTIVITY_SERVICE);
			ConnectivityManager cm = (ConnectivityManager) o;
			NetworkInfo net = cm.getActiveNetworkInfo();
			if(net != null && net.getType() == TYPE_WIFI && net.isConnected()) {
				LOG.info("Connected to Wi-Fi");
				if(socket == null || socket.isClosed()) bind();
			} else {
				LOG.info("Not connected to Wi-Fi");
				tryToClose(socket);
			}
		}
	}
}