Develop Reference

Issues with getting data from vector using Java and objects

I'm currently playing around with Java, JForms, and the Twitter4j library. Trying to create a way to populate a vector with tweetID's in order to perform actions on them (Retweets, Favorites, replies, etc.). I'm having a bit of a problem with either:
A. Not being able to add to the vector, or
B. Not being able to read from it.
Based on what I've seen from the logger output, I'm positive I'm not adding to the array correctly. Could somebody take a look with me and see what's going on?
main.java (The code to add to the vector with the tweet ID.)
private void btn_refreshTimelineActionPerformed(java.awt.event.ActionEvent evt) {
TwitterUtilities tu = new TwitterUtilities();
Twitter twitter = tu.getConnect();
// Gets tweet information.
List<Status> statuses = null;
try {
statuses = twitter.getHomeTimeline();
} catch (TwitterException ex) {
Logger.getLogger(main.class.getName()).log(Level.SEVERE, null, ex);
}
// Init table.
DefaultTableModel model = (DefaultTableModel) tbl_tweets.getModel();
// Clear table.
model.setRowCount(0);
// Populate table.
for (Status status : statuses)
{
tu.setTargetID(status.getId());
Vector row = new Vector();
row.add(status.getUser().getName());
row.add(status.getText());
model.addRow(row);
}
}
main.java (The part where getTargetTweetID is invoked.)
private void btn_favoriteActionPerformed(java.awt.event.ActionEvent evt) {
TwitterUtilities tu = new TwitterUtilities();
Twitter twitter = tu.getConnect();
int targetIndex = tbl_tweets.getSelectedRow();
long tweetID = tu.getTargetTweetID(targetIndex);
try {
twitter.createFavorite(tweetID);
} catch (TwitterException ex) {
Logger.getLogger(main.class.getName()).log(Level.SEVERE, null, ex);
}
}
TwitterUtilities.java
public class TwitterUtilities {
public Vector tweetIDVector;
// Other stuff... but here's the important stuff.
public void setTargetID(long targetStatus)
{
this.tweetIDVector.addElement(targetStatus);
}
public long getTargetTweetID(int targetIndex)
{
// Get tweet ID for the selected tweet.
Object targetTweetID = this.tweetIDVector.get(targetIndex);
return (long) targetTweetID;
}
}
The error message that I'm getting upon runtime:
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 1
Any help would be greatly appreciated!
EDIT: After working with the suggestions, I've now updated the following code to this new setup:
TwitterUtilities.java
public class TwitterUtilities {
public Vector tweetIDVector = new Vector<>();
// More fun stuff...
public void setTargetID(long targetStatus)
{
this.tweetIDVector.addElement(targetStatus);
for (int i = 0; i <= tweetIDVector.size(); i++)
{
System.out.println(tweetIDVector.get(i));
}
}
And so now the following happens on run:
838641565769871360
Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 1
EDIT 2: Changed the Vector into a List. Loading the Tweet ID's is working. Also changed the <= in the for loop to <. Now it is loading everything the way it's supposed to. Still having issues with getting data from the List in the getTargetTweetID.

ParseQuery Array to lowercase before search

I have issue with searching trough ParseQuery Array.
I need case insensitive search, so i need to convert my array to lowercase.
I tried query.whereMatches and query.whereContains without success.
My guess is to make new method that would convert all data from ParseQuery to lowercaseString Array.
Am i right with this one?
Here's the example code for setting search result list:
private void setList(boolean hardRefresh) {
// stop any ongoing progress dialog
cancelProgressDialog();
reloadTags();
reloadContents();
ParseQuery<Note> query = Note.getQuery()
.fromLocalDatastore()
.orderByDescending("date");
String searchStr = searchText.getText().toString().toLowerCase();
if (!searchStr.isEmpty()) {
query.whereMatches(Note.FIELD_DETAIL, searchStr);
}
try {
mNotes = query.find();
if (adapter == null) {
adapter = new ListAdapter();
notesGridView.setAdapter(adapter);
} else {
adapter.notifyDataSetChanged();
}
} catch (ParseException e) {
e.printStackTrace();
}

For case insensitive search try like this :
if (!searchStr.isEmpty()) {
query.whereMatches(Note.FIELD_DETAIL, searchStr,"i");
}

Storing all ParseFiles for a given ParseUser?

I'm new to Parse and was wondering if there is any way to store all the ParseFiles (in this case images) for a given ParseUser into something like an ArrayList?
Here's my code:
public ArrayList<ParseFile> getFiles() {
ArrayList<ParseFile> files = new ArrayList<ParseFile>();
//mUser is the current ParseUser
ParseQuery<ParseObject> query = ParseQuery.getQuery(mUser.getUsername());
query.findInBackground(new FindCallback<ParseObject>() {
public void done(List<ParseObject> fileList, ParseException e) {
if (e == null) {
Log.d("FILES", "Retrieved " + fileList.size() + " files");
for(ParseObject ch:fileList) {
image = ch.getParseFile("image");
files.add(image);
#Override
public void done(byte[] arg0, ParseException arg1) {
//nothing to do here
}
});
}
Log.i("TAG", ": " + files.size());
} else {
Log.d("FILES", "Error: " + e.getMessage());
}
}
});
Log.i("DONE", ": " + files.size());
return files;
}
When I'm inside done(), the 3 images I have for this particular user are added and I get an ArrayList of size 3 which is to be expected. When I'm outside of done(), the size of the ArrayList goes back to 0, which I'm assuming is because it's being referenced outside of the query. And sure enough it returns an empty ArrayList (not too shocking).
I feel like this should be an easy solution but I can't seem to figure it out. I've tried to make a static ArrayList variable but that doesn't seem to work either. Any idea on how to return the desired ArrayList?

I believe the problem is that the outside thread still continues before your background process is completed. In other words..
1. query.findInBackground(....);
2. Log.i("DONE" ....);
.. 2. is executed before 1. completes. The whole point of Parse "inBackground" is that it completes actions that your thread is not dependent on. If you need to do something with the List, you should do it in the same thread as the background thread or not do it "inBackground".

Try like this
ParseQuery<ParseObject> query = ParseQuery.getQuery(mUser.getUsername());
List<ParseObject>imageList=query.find();
try {
Arraylist<ParseFile> files = new Arraylist<ParseFile>files();
ParseFile image;
for(int i =0;i<imageList.size();i++)
{
image = imageList.get(i).getParseFile("image");
files.add(image);
}
}
catch()
{
}

Avoiding duplicate entries in a mongoDB with Java and JSON objects

I´m developing an analyzing program for Twitter Data.
I´m using mongoDB and at the moment. I try to write a Java program to get tweets from the Twitter API and put them in the database.
Getting the Tweets already works very well, but I have a problem when I want to put them in the database. As the Twitter API often returns just the same Tweets, I have to place some kind of index in the database.
First of all, I connect to the database and get the collection related to the search-term, or create this collection if this doesn´t exist.
public void connectdb(String keyword)
{
try {
// on constructor load initialize MongoDB and load collection
initMongoDB();
items = db.getCollection(keyword);
BasicDBObject index = new BasicDBObject("tweet_ID", 1);
items.ensureIndex(index);
} catch (MongoException ex) {
System.out.println("MongoException :" + ex.getMessage());
}
}
Then I get the tweets and put them in the database:
public void getTweetByQuery(boolean loadRecords, String keyword) {
if (cb != null) {
TwitterFactory tf = new TwitterFactory(cb.build());
Twitter twitter = tf.getInstance();
try {
Query query = new Query(keyword);
query.setCount(50);
QueryResult result;
result = twitter.search(query);
System.out.println("Getting Tweets...");
List<Status> tweets = result.getTweets();
for (Status tweet : tweets) {
BasicDBObject basicObj = new BasicDBObject();
basicObj.put("user_name", tweet.getUser().getScreenName());
basicObj.put("retweet_count", tweet.getRetweetCount());
basicObj.put("tweet_followers_count", tweet.getUser().getFollowersCount());
UserMentionEntity[] mentioned = tweet.getUserMentionEntities();
basicObj.put("tweet_mentioned_count", mentioned.length);
basicObj.put("tweet_ID", tweet.getId());
basicObj.put("tweet_text", tweet.getText());
if (mentioned.length > 0) {
// System.out.println("Mentioned length " + mentioned.length + " Mentioned: " + mentioned[0].getName());
}
try {
items.insert(basicObj);
} catch (Exception e) {
System.out.println("MongoDB Connection Error : " + e.getMessage());
loadMenu();
}
}
// Printing fetched records from DB.
if (loadRecords) {
getTweetsRecords();
}
} catch (TwitterException te) {
System.out.println("te.getErrorCode() " + te.getErrorCode());
System.out.println("te.getExceptionCode() " + te.getExceptionCode());
System.out.println("te.getStatusCode() " + te.getStatusCode());
if (te.getStatusCode() == 401) {
System.out.println("Twitter Error : \nAuthentication credentials (https://dev.twitter.com/pages/auth) were missing or incorrect.\nEnsure that you have set valid consumer key/secret, access token/secret, and the system clock is in sync.");
} else {
System.out.println("Twitter Error : " + te.getMessage());
}
loadMenu();
}
} else {
System.out.println("MongoDB is not Connected! Please check mongoDB intance running..");
}
}
But as I mentioned before, there are often the same tweets, and they have duplicates in the database.
I think the tweet_ID field is a good field for an index and should be unique in the collection.

Set the unique option on your index to have MongoDb enforce uniqueness:
items.ensureIndex(index, new BasicDBObject("unique", true));
Note that you'll need to manually drop the existing index and remove all duplicates or you won't be able to create the unique index.

This question is already answered but I would like to contribute a bit since MongoDB API 2.11 offers a method which receives unique option as a parameter:
public void ensureIndex(DBObject keys, String name, boolean unique)
A minor remind to someone who would like to store json documents on MongoDBNote is that uniqueness must be applied to a BasicObject key and not over values. For example:
BasicDBObject basicObj = new BasicDBObject();
basicObj.put("user_name", tweet.getUser().getScreenName());
basicObj.put("retweet_count", tweet.getRetweetCount());
basicObj.put("tweet_ID", tweet.getId());
basicObj.put("tweet_text", tweet.getText());
basicObj.put("a_json_text", "{"info_details":{"info_id":"1234"},"info_date":{"year":"2012"}, {"month":"12"}, {"day":"10"}}");
On this case, you can create unique index only to basic object keys:
BasicDBObject index = new BasicDBObject();
int directionOrder = 1;
index.put("tweet_ID", directionOrder);
boolean isUnique = true;
items.ensureIndex(index, "unique_tweet_ID", isUnique);
Any index regarding JSON value like "info_id" would not work since it´s not a BasicObject key.
Using indexes on MongDB is not as easy as it sounds. You may also check MongoDB docs for more details here Mongo Indexing Tutorials and Mongo Index Concepts. Direction order might be pretty important to understand once you need a composed index which is well explained here Why Direction order matter.

How to query value of column that is set as pointer to other table in Parse

I am using Parse for my app. I want to query a table with column that set to be a pointer to other table. Here is the query:
ParseQuery query = new ParseQuery("CategoryAttribute");
query.whereEqualTo("categoryId", categoryId);
query.findInBackground(new FindCallback() {
#Override
public void done(List<ParseObject> categoryAttributes, ParseException e) {
if (e == null) {
for (int i = 0; i < categoryAttributes.size(); i++){
String atributeCategoryId = categoryAttributes.get(i).getString("categoryId");
String attributeKey = categoryAttributes.get(i).getString("attributeKey");
String attributeValue = categoryAttributes.get(i).getString("attributeValue");
setCategoryAtributeRow(atributeCategoryId, attributeKey, attributeValue);
}
} else {
Log.d("score", "Error: " + e.getMessage());
}
}
});
So the categoryId column is a pointer to other table. Other columns work fine.
I tried to scan the API and the guides but couldn't find needed solution. Help would be much appreciated!

Here is the solution to this one:
First you need to create a ParseObject from the type of your table:
ParseObject sale = ParseObject.createParseObject("Sale");
Then you need to get the ParseObject from the result:
sale = result.getParseObject(pointer_field);
Now you can pull from sale any field that it has just as you would do it normally, for example:
sale.getString("some_field")
Note:
When you are doing your query you must to include the pointer field if you want to be able to extract the data from it after the query will be returned. The result:
query.include("pointer_field")
Hope it helps

#Akshat Agarwal, here is a example in JavaScript:
var parseObj = Parse.Object.extend('parseObj');
new Parse.Query(parseObj)
.include('pointerField')
.find(function (data) {
data.get('pointerField').get('fieldName');
});

For iOS
PFQuery *parseQuery = [PFQuery queryWithClassName:#"MyClass"];
[parseQuery whereKey:#"categoryId" equalTo:categoryId];
[parseQuery includeKey:#"pinter_field"];
[parseQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
//
}];