edu.vt.alerts.android.library.tasks.FetchAlertSummaryTask.java Source code

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Here is the source code for edu.vt.alerts.android.library.tasks.FetchAlertSummaryTask.java

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/*
 * File created on Feb 28, 2014 
 *
 * Copyright 2008-2014 Virginia Polytechnic Institute and State University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */
package edu.vt.alerts.android.library.tasks;

import java.util.Date;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.BasicResponseHandler;

import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import edu.vt.alerts.android.library.api.Environment;
import edu.vt.alerts.android.library.api.domain.summary.AlertSummary;
import edu.vt.alerts.android.library.callbacks.AlertSummaryCallback;
import edu.vt.alerts.android.library.exceptions.UnexpectedNetworkResponseException;
import edu.vt.alerts.android.library.util.HttpClientFactory;
import edu.vt.alerts.android.library.util.marshal.JsonAlertSummaryUnmarshaller;
import edu.vt.alerts.android.library.util.marshal.Unmarshaller;

/**
 * AsyncTask that is used to fetch the summaries for alerts from the VT-APNS
 * system.
 *
 * @author Michael Irwin
 */
public class FetchAlertSummaryTask extends AsyncTask<Date, Void, TaskResult<List<AlertSummary>>> {

    private final Context context;
    private final Environment environment;
    private final AlertSummaryCallback callback;

    private Unmarshaller<List<AlertSummary>> unmarshaller = new JsonAlertSummaryUnmarshaller();
    private HttpClientFactory httpClientFactory = new HttpClientFactory();

    /**
     * Create a new instance
     * @param context The application context
     * @param environment The alerts environment to run with
     * @param callback A callback to notify of results
     */
    public FetchAlertSummaryTask(Context context, Environment environment, AlertSummaryCallback callback) {
        this.context = context;
        this.environment = environment;
        this.callback = callback;
    }

    @Override
    protected TaskResult<List<AlertSummary>> doInBackground(Date... params) {
        try {
            HttpClient client = httpClientFactory.generateSubscriberClient(context, environment);
            String suffix = (params.length > 0) ? "?timestamp=" + params[0].getTime() / 1000 : "";
            HttpGet get = new HttpGet(environment.getAlertsSummaryUrl() + suffix);
            get.addHeader("Accept", unmarshaller.getMimeType());

            HttpResponse response = client.execute(get);
            StatusLine statusLine = response.getStatusLine();
            int statusCode = statusLine.getStatusCode();
            if (statusCode < 200 || statusCode >= 300)
                throw new UnexpectedNetworkResponseException(
                        "Unexpected response (" + statusCode + ") when fetching summaries", statusCode,
                        statusLine.getReasonPhrase());

            String alertSummary = new BasicResponseHandler().handleResponse(response);
            Log.i("alertsService", "Retrieved the following:");
            Log.i("alertsService", alertSummary);
            List<AlertSummary> alerts = unmarshaller.convertData(alertSummary);
            return new TaskResult<List<AlertSummary>>(alerts, null);
        } catch (Exception e) {
            return new TaskResult<List<AlertSummary>>(null, e);
        }
    }

    @Override
    protected void onPostExecute(TaskResult<List<AlertSummary>> result) {
        if (result.exceptionThrown())
            callback.exceptionThrown(result.getException());
        else
            callback.alertsRetrieved(result.getResult());
    }

}