Using XPages to get data from managed bean - json

Question

I am trying to create a list of Twitter users, populating it with the number of followers for the user and their profile image. Because of Twitter's API, you need to get an access token for your application prior to using their REST API. I thought the best way to do this was via Java and a managed bean. I posted the code below, which currently works. I get the access token from Twitter, then make the API call to get the user info, which is in JSON.
My question is, what is the best way to parse the JSON and iterate over a list of user names to create a table/grid on the XPage?
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import javax.net.ssl.HttpsURLConnection;
import org.apache.commons.codec.binary.Base64;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
public class TwitterUser implements Serializable {
private static final String consumerKey = "xxxx";
private static final String consumerSecret = "xxxx";
private static final String twitterApiUrl = "https://api.twitter.com";
private static final long serialVersionUID = -2084825539627902622L;
private static String accessToken;
private String twitUser;
public TwitterUser() {
this.twitUser = null;
}
public String getTwitterUser(String screenName) {
try {
this.requestTwitterUserInfo(screenName);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return twitUser;
}
public void setTwitterUser() {
twitUser = twitUser;
}
//Encodes the consumer key and secret to create the basic authorization key
private static String encodeKeys(String consumerKey, String consumerSecret) {
try {
String encodedConsumerKey = URLEncoder.encode(consumerKey, "UTF-8");
String encodedConsumerSecret = URLEncoder.encode(consumerSecret, "UTF-8");
String fullKey = encodedConsumerKey + ":" + encodedConsumerSecret;
byte[] encodedBytes = Base64.encodeBase64(fullKey.getBytes());
return new String(encodedBytes);
}
catch (UnsupportedEncodingException e) {
return new String();
}
}
//Constructs the request for requesting a bearer token and returns that token as a string
private static void requestAccessToken() throws IOException {
HttpsURLConnection connection = null;
String endPointUrl = twitterApiUrl + "/oauth2/token";
String encodedCredentials = encodeKeys(consumerKey,consumerSecret);
String key = "";
try {
URL url = new URL(endPointUrl);
connection = (HttpsURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("POST");
connection.setRequestProperty("Host", "api.twitter.com");
connection.setRequestProperty("User-Agent", "Your Program Name");
connection.setRequestProperty("Authorization", "Basic " + encodedCredentials);
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
connection.setRequestProperty("Content-Length", "29");
connection.setUseCaches(false);
writeRequest(connection, "grant_type=client_credentials");
// Parse the JSON response into a JSON mapped object to fetch fields from.
JSONObject obj = (JSONObject)JSONValue.parse(readResponse(connection));
if (obj != null) {
String tokenType = (String)obj.get("token_type");
String token = (String)obj.get("access_token");
accessToken = ((tokenType.equals("bearer")) && (token != null)) ? token : "";
}
else {
accessToken = null;
}
}
catch (MalformedURLException e) {
throw new IOException("Invalid endpoint URL specified.", e);
}
finally {
if (connection != null) {
connection.disconnect();
}
}
}
private void requestTwitterUserInfo(String sn) throws IOException {
HttpsURLConnection connection = null;
if (accessToken == null) {
requestAccessToken();
}
String count = "";
try {
URL url = new URL(twitterApiUrl + "/1.1/users/show.json?screen_name=" + sn);
connection = (HttpsURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("GET");
connection.setRequestProperty("Host", "api.twitter.com");
connection.setRequestProperty("User-Agent", "Your Program Name");
connection.setRequestProperty("Authorization", "Bearer " + accessToken);
connection.setRequestProperty("Content-Type", "text/plain");
connection.setUseCaches(false);
}
catch (MalformedURLException e) {
throw new IOException("Invalid endpoint URL specified.", e);
}
finally {
if (connection != null) {
connection.disconnect();
}
}
twitUser = readResponse(connection);
}
//Writes a request to a connection
private static boolean writeRequest(HttpsURLConnection connection, String textBody) {
try {
BufferedWriter wr = new BufferedWriter(new OutputStreamWriter(connection.getOutputStream()));
wr.write(textBody);
wr.flush();
wr.close();
return true;
}
catch (IOException e) { return false; }
}
// Reads a response for a given connection and returns it as a string.
private static String readResponse(HttpsURLConnection connection) {
try {
StringBuilder str = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = "";
while((line = br.readLine()) != null) {
str.append(line + System.getProperty("line.separator"));
}
return str.toString();
}
catch (IOException e) { return new String(); }
}
}

Answer 1

A few pointers:
Domino has the Apache HTTP client classes. They tend to be more robust than raw HTTP connections
Define a new class as a bean that contains all values that you want to see per row. You only need the getters public
add a method to your managed bean Collection getAllData()
bind that to a repeat control
you then can use repeatvar.someProperty in column values in EL
use better names than I just used