JoinConferencePoller.java

package dk.silverbullet.telemed.video;

import android.util.Log;
import com.google.gson.annotations.Expose;
import dk.silverbullet.telemed.MainActivity;
import dk.silverbullet.telemed.questionnaire.Questionnaire;
import dk.silverbullet.telemed.rest.client.lowlevel.HttpHeaderBuilder;
import dk.silverbullet.telemed.rest.httpclient.HttpClientFactory;
import dk.silverbullet.telemed.utils.Json;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;

import java.io.IOException;
import java.net.URL;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;

import static java.util.concurrent.TimeUnit.SECONDS;

public class JoinConferencePoller {
    private static final String TAG = "ConferenceHandler";
    private static final int FIVE_SECONDS_IN_MILLIS = 5000;
    private final MainActivity mainActivity;
    private final Questionnaire mainQuestionnaire;
    private volatile boolean stopped;
    private volatile HttpGet httpGet;

    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
    private Runnable checkForConferenceRunnable;

    public JoinConferencePoller(final MainActivity mainActivity, Questionnaire mainQuestionnaire) {
        this.mainActivity = mainActivity;
        this.mainQuestionnaire = mainQuestionnaire;

        checkForConferenceRunnable = new Runnable() {
            @Override
            public void run() {
                PendingConferenceResponse checkForConferenceResponse = checkForConference();
                if (!checkForConferenceResponse.roomKey.isEmpty()) {
                    Log.d(TAG, "Got roomkey" + checkForConferenceResponse.roomKey + "and service url:" + checkForConferenceResponse.serviceUrl);
                    mainActivity.startVideoConference(checkForConferenceResponse.roomKey, checkForConferenceResponse.serviceUrl);

                    scheduler.shutdown();
                }
            }
        };
    }

    public void start() {
        scheduler.scheduleWithFixedDelay(checkForConferenceRunnable, 0, 2, SECONDS);
    }

    public void stop() {
        stopped = true;
        final HttpGet pendingHttpGet = httpGet;
        if (pendingHttpGet != null) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    pendingHttpGet.abort();
                }
            }).start();
        }
        scheduler.shutdownNow();
    }

    private PendingConferenceResponse checkForConference() {
        try {
            // We don't use the otherwise nice and simple RestClient here, since we want to set an infinite timeout
            // period AND hold on to our HttpGet object since we might like to abort it.

            URL url = new URL(mainActivity.getServerURL());
            httpGet = new HttpGet(new URL(url, "rest/conference/patientHasPendingConference").toExternalForm());
            new HttpHeaderBuilder(httpGet, mainQuestionnaire)
                    .withAuthentication()
                    .withAcceptTypeJSON()
                    .withContentTypeJSON();

            HttpClient httpClient = createHttpClientWithInfiniteTimeout();
            String result = httpClient.execute(httpGet, new BasicResponseHandler());

            if (!stopped && !result.isEmpty()) {
                return Json.parse(result, PendingConferenceResponse.class);
            }
        } catch (IOException e) {
            // If we're trying to stop this poller thread by aborting the GET request, we get an IOException. In
            // that case, we don't log anything.
            if (!stopped) {
                Log.e(TAG, "Could not check for pending conference", e);
            }
        }
        return new PendingConferenceResponse();
    }

    private HttpClient createHttpClientWithInfiniteTimeout() {
        HttpClient httpClient = HttpClientFactory.createHttpClient(mainActivity);

        HttpParams httpParameters = httpClient.getParams();
        HttpConnectionParams.setConnectionTimeout(httpParameters, FIVE_SECONDS_IN_MILLIS);
        HttpConnectionParams.setSoTimeout(httpParameters, 0);
        return httpClient;
    }

    class PendingConferenceResponse {
        @Expose String roomKey = "";
        @Expose String serviceUrl = "";
    }
}