Android Open Source - cheepcheep Twitter J S O N Serializer

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License

The source code is released under:
Apache License
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Java Source Code

package org.tarrio.cheepcheep.service;
/*from w  w w.jav  a 2s  .c  o m*/
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Locale;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.tarrio.cheepcheep.exceptions.ParseError;
import org.tarrio.cheepcheep.model.Tweet;
import org.tarrio.cheepcheep.model.User;

/**
 * Class for serializing and deserializing tweets and timelines from and to JSON
 * objects.
 */
public class TwitterJSONSerializer {

  private static final String DATE_FORMAT = "EEE MMM dd HH:mm:ss ZZZZ yyyy";
  private static final SimpleDateFormat df = new SimpleDateFormat(DATE_FORMAT, Locale.US);

  /**
   * Converts a JSON array representing a Twitter timeline into a list of
   * tweets.
   * 
   * @param statuses
   *            the JSON array that contains the timeline.
   * @return a list of tweets.
   * @throws JSONException
   *             if there was a problem parsing the JSON.
   * @throws ParseError
   *             if there was a problem parsing a date.
   */
  public static List<Tweet> deserializeTimeline(JSONArray statuses)
      throws JSONException, ParseError {
    List<Tweet> tweets = new ArrayList<Tweet>();
    int numElems = statuses.length();
    for (int i = 0; i < numElems; ++i)
      tweets.add(deserializeTweet(statuses.getJSONObject(i)));
    return tweets;
  }

  /**
   * Converts a JSON object representing a Twitter status into a tweet.
   * 
   * @param status
   *            the JSON object that contains the status.
   * @return a single tweet.
   * @throws JSONException
   *             if there was a problem parsing the JSON.
   * @throws ParseError
   *             if there was a problem parsing a date.
   */
  public static Tweet deserializeTweet(JSONObject status)
      throws JSONException, ParseError {
    Tweet tweet = new Tweet();
    tweet.setId(status.getLong("id"));
    tweet.setDateTime(parseDate(status.getString("created_at")));
    if (status.has("retweeted_status")) {
      Tweet reTweeted = deserializeTweet(status.getJSONObject("retweeted_status"));
      StringBuilder sb = new StringBuilder("RT @");
      sb.append(reTweeted.getScreenName());
      sb.append(" ");
      sb.append(reTweeted.getText());
      tweet.setText(sb.toString());
      tweet.setInReplyToId(reTweeted.getInReplyToId());
      tweet.setInReplyToScreenName(reTweeted.getInReplyToScreenName());
    } else {
      tweet.setText(unescapeHtml(status.getString("text")));
      tweet.setInReplyToId(getLongINN(status, "in_reply_to_status_id"));
      tweet.setInReplyToScreenName(getStringINN(status,
          "in_reply_to_screen_name"));
    }
    JSONObject user = status.getJSONObject("user");
    tweet.setScreenName(user.getString("screen_name"));
    return tweet;
  }

  /**
   * Converts a JSON object representing a Twitter user into an User instance.
   * 
   * @param json
   *            the JSON object that represents the user.
   * @return an instance of the User class.
   * @throws JSONException
   *             if there was a problem parsing the JSON.
   */
  public static User deserializeUser(JSONObject json) throws JSONException {
    User user = new User();
    user.setScreenName(json.getString("screen_name"));
    user.setRealName(getStringINN(json, "name"));
    user.setAvatarUrl(json.getString("profile_image_url"));
    user.setDescription(getStringINN(json, "description"));
    user.setLocation(getStringINN(json, "location"));
    user.setHomepage(getStringINN(json, "url"));
    user.setNumFollowing(json.getLong("friends_count"));
    user.setNumFollowers(json.getLong("followers_count"));
    user.setNumUpdates(json.getLong("statuses_count"));
    user.setFollowing(getBooleanINN(json, "following"));
    return user;
  }

  private static long getLongINN(JSONObject json, String key)
      throws JSONException {
    if (!json.isNull(key))
      return json.getLong(key);
    else
      return 0;
  }

  private static String getStringINN(JSONObject json, String key)
      throws JSONException {
    if (!json.isNull(key))
      return json.getString(key);
    else
      return "";
  }
  
  private static boolean getBooleanINN(JSONObject json, String key) throws JSONException {
    if (!json.isNull(key))
      return json.getBoolean(key);
    else
      return false;
  }

  private static Date parseDate(String date) throws ParseError {
    try {
      return df.parse(date);
    } catch (ParseException e) {
      throw new ParseError("Error parsing a date", e);
    }
  }

  private static String unescapeHtml(String text) {
    return text.replace("&lt;", "<").replace("&gt;", ">").replace("&amp;",
        "&");
  }

}
Java Source Code List
