This is a java api for the quandl dataservice. It's goal is to make it easy for you to use Quandl's data for a java application.
Our first step is to open a connection to quandl using an api key. This connection will facilitate the creation of dataset objects (dataset downloads).
Login to Quandl and go to http://www.quandl.com/users/edit
Click "API" and you will see your key. You will want to use this as the rate limits are higher if you are using a key.
//open connection with key
QuandlConnection q = new QuandlConnection("my key");
If you don't provide a key (or supply a bad one), you can still open a connection. You'll just be notified that your rate limit is significantly smaller.
//open connection without key
QuandlConnection r = new QuandlConnection();
QDataset is the basic quandl-java object. It downloads data in JSON form and converts it into a java object. The minimal setting you must supply is the "Quandle Code"... which is available on Quandl dataset pages.
//get dataset from keyrange
QDataset data1 = q.getDataset("PRAGUESE/PX");
//get dataset between two sets of dates... don't forget to use this format for the date.
QDataset data2 = q.getDatasetBetweenDates("PRAGUESE/PX","2012-01-01","2012-11-26");
This version lets you set your custom parameters. You can pick from any parameters on the Quandl API page. http://www.quandl.com/api
//get dataset with custom parameters
HashMap<String, String> params = new HashMap<String, String>();
params.put("trim_start","2012-09-30");
params.put("code","PX");
params.put("source_code","PRAGUESE");
QDataset data3 = q.getDatasetWithParams(params);
A few examples of extracting the data from a QDataset.
//get Dataset as array matrix
ArrayList<ArrayList<String>> data3Matrix = data3.getArrayMatrix();
//get Dataset as String Matrix
String[][] data3StringMatrix = data3.getStringMatrix();