Install flows in OpenDaylight using Java

Although I had already done a similar post for this here, guess there are a lot of folks who are not able get everything working together without the actual source code.

So I thought it might be helpful if I provide with some ready to use project/code for installing flows using java.

1. Download the source code.

Download the source code of project “OpenDaylightFlowInstall” from my GitHub here. This will give you the following:

  1. FlowManager Class – Responsible for adding/deleting flows
  2. Tester Class – Responsible for actually passing the data & calling FlowManager class to install/delete flows.
  3. ODL Class – Responsible for OpenDaylight settings.

2. Import/Setup the code

You can import the code into eclipse as a java project or setup your command. Whatever you prefer.

To import the code in eclipse use “Import as Java Project” option and make sure that your “Project –> Build Automatically” is switched on.


Also make sure that the two jars in lib folder are in classpath else compilation will fail.

3. Network & OpenDaylight Setup

I have a mininet running with one switch and two hosts which are able to ping each other & connected to OpenDaylight.



4 Running the program

If you are using eclipse, simply right clicking on the tester class and saying “Run as Java Application” should run the code. Make sure of two things:

  1. Supply the right Src/Dest IP & Node details in the

  2. Correct values in under settings.

Once you run the program, the action DROP will be installed and ping will stop working.

3 odl2

Let me know, if you get stuck & i’ll try to help.


Using JAVA to call OpenDaylight REST NBI to fetch all nodes

As with my previous post where I have noted about how to call OpenDaylight’s REST NBI using JQuery, here, I give a snippet of code to call the same service using JAVA which many people use to write apps on top of SDN Controllers.

You will need two additional jar’s to do this.

  1. Apache Codec for encoding the password in Base64.
  2. Jettison to use the JSONObject format for request/response.

Once you have included the above two jars in your classpath, here something you will have to do to get all ODL nodes:


import org.apache.commons.codec.binary.Base64;
import org.codehaus.jettison.json.JSONObject;

public class OpenDaylightHelper {

    public static JSONObject getNodes(String user, String password,
            String baseURL) {

        StringBuffer result = new StringBuffer();
        try {

            if (!baseURL.contains("http")) {
                baseURL = "http://" + baseURL;
            baseURL = baseURL + "/controller/nb/v2/switchmanager/default/nodes";

            // Create URL = base URL + container
            URL url = new URL(baseURL);

            // Create authentication string and encode it to Base64
            String authStr = user + ":" + password;
            String encodedAuthStr = Base64.encodeBase64String(authStr

            // Create Http connection
            HttpURLConnection connection = (HttpURLConnection) url

            // Set connection properties
            connection.setRequestProperty("Authorization", "Basic "
                    + encodedAuthStr);
            connection.setRequestProperty("Accept", "application/json");

            // Get the response from connection's inputStream
            InputStream content = (InputStream) connection.getInputStream();
            BufferedReader in = new BufferedReader(new InputStreamReader(
            String line = "";
            while ((line = in.readLine()) != null) {

            JSONObject nodes = new JSONObject(result.toString());
            return nodes;
        } catch (Exception e) {

        return null;

This call should fetch you all the nodes discovered in the topology of OpenDaylight.

More details about ODL NBI can be found on their Wiki.