Android Open Source - android-augment-reality-framework Network Data Source

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License

The source code is released under:

GNU General Public License

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Java Source Code

package com.jwetherell.augmented_reality.data;
/*from   w w w.j  a va 2  s.  co m*/
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;

import org.json.JSONException;
import org.json.JSONObject;

import com.jwetherell.augmented_reality.ui.Marker;


/**
 * This abstract class should be extended for new data sources. It has many
 * methods to get and parse data from numerous web sources.
 * 
 * @author Justin Wetherell <phishman3579@gmail.com>
 */
public abstract class NetworkDataSource extends DataSource {

    protected static final int MAX = 5;
    protected static final int READ_TIMEOUT = 10000;
    protected static final int CONNECT_TIMEOUT = 10000;

    protected List<Marker> markersCache = null;

    public abstract String createRequestURL(double lat, double lon, double alt, float radius, String locale);

    public abstract List<Marker> parse(JSONObject root);

    /**
     * This method get the Markers if they have already been downloaded once.
     * 
     * @return List of Marker objects or NULL if not downloaded yet.
     */
    public List<Marker> getMarkers() {
        return markersCache;
    }

    protected static InputStream getHttpGETInputStream(String urlStr) {
        if (urlStr == null) throw new NullPointerException();

        InputStream is = null;
        URLConnection conn = null;

        try {
            if (urlStr.startsWith("file://")) return new FileInputStream(urlStr.replace("file://", ""));

            URL url = new URL(urlStr);
            conn = url.openConnection();
            conn.setReadTimeout(READ_TIMEOUT);
            conn.setConnectTimeout(CONNECT_TIMEOUT);

            is = conn.getInputStream();

            return is;
        } catch (Exception ex) {
            try {
                is.close();
            } catch (Exception e) {
                // Ignore
            }
            try {
                if (conn instanceof HttpURLConnection) ((HttpURLConnection) conn).disconnect();
            } catch (Exception e) {
                // Ignore
            }
            ex.printStackTrace();
        }

        return null;
    }

    protected String getHttpInputString(InputStream is) {
        if (is == null) throw new NullPointerException();

        BufferedReader reader = new BufferedReader(new InputStreamReader(is), 8 * 1024);
        StringBuilder sb = new StringBuilder();

        try {
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }

    /**
     * Parse the given URL for JSON Objects.
     * 
     * @param url
     *            URL to parse.
     * @return List of Marker's from the URL.
     * @throws NullPointerException
     *             if the String URL is NULL.
     */
    public List<Marker> parse(String url) {
        if (url == null) throw new NullPointerException();

        InputStream stream = null;
        stream = getHttpGETInputStream(url);
        if (stream == null) throw new NullPointerException();

        String string = null;
        string = getHttpInputString(stream);
        if (string == null) throw new NullPointerException();

        JSONObject json = null;
        try {
            json = new JSONObject(string);
        } catch (JSONException e) {
            e.printStackTrace();
        }
        if (json == null) throw new NullPointerException();

        return parse(json);
    }
}

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