Sajith's Blogspot: server

12 December 2015

RESTful web service In 5 Minutes using DropWizard

These days I am Learning new framework called "Dropwizard".So I thought I want to share what I learn from Dropwizard. Before going to what is Dropwizard I want to tell some difficulties when building rest server application.When I was in university I don't know how to implement Restful webservice and i thought it was difficult task even for Testing purpose.Then I learn apache CXF web server and the problem was there are lot of dependencies need to create rest server. Ex:-Apache Cxf,Jackson serialization library,log4j for logging ,Junit for Testing And other libraries.So Even for me to hard to remember all the dependency libraries. So the Solution is Dropwizard. Dropwizard is Lightweight framework which have all the dependencies in one place. Dropwizard also support to expand to your project in layered structure such as api/db/client.

What is Drop-wizard

Drop wizard is simply All the listed libraries in one package.

metrics
jetty
jersey
jackson
jdbi
hibernate
logback
mustache
freemarker

Start Using Maven archetype

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mvn archetype:generate -DgroupId=dec.mchoice.tech.talk -DartifactId=Sample-dw-app -Dname=SampleApplication -Dpackage=dev.mchoice.tech.talk
dev.innova.drp -DarchetypeGroupId=io.dropwizard.archetypes -DarchetypeArtifactId=java-simple -DinteractiveMode=false

After creating project it will create this kind of project structure.

Biggest advantage of use maven archetype no need to configure any dependencies or plugin in POM.xml file and it will generate executable jar file . Next step is create Rest API end point.

@Path("/student")

public class StudentManagement {
    @POST

    @Timed

    @Path("/save")

    @Produces(MediaType.APPLICATION_JSON)

    @Consumes({MediaType.APPLICATION_JSON})

    public Response addPerson(Student student) {

        Map<String, Object> response = new HashMap<>();

        response.put("statusCode", "S1000");

        response.put("description", "Successfully added Student");

        return Response.ok(response).build();

    }

}

And then you have to register your rest API in drop wizard configuration.

@Override
    public void run(final SampleApplicationConfiguration configuration,

                    final Environment environment) {

        environment.jersey().register(new StudentManagement());

    }

And now All the API related stuff are finished.So you need to run your Application.First go to target folder in project and run

1	java -jar Sample-dw-app-1.0-SNAPSHOT.jar server

After running it will start in 8080 port(application port) and there is another port 8081 (Admin port ).
Next tutorial we will discuss how to change the default configurations and what are the usages of admin port.

Then you can use curl request or postmen to send request and check the Rest API.

04 October 2015

Android Google cloud messaging Test server

Java GCM Testing Server

Today I will share how to create java Testing Application for send android GCM notifications to android client.There are lot of examples how to create android GCM client application but for testing the notification flow you need server.But I couldn't found any good example how to create java server.So I found Library for send notifications so i used that library and create simple swing application to send notification.

Sample Code

This is the code-sample which I have already pushed in to github location(https://github.com/sajith4u/android-gsm-sample).

package dev.innova.sajith;

import com.google.android.gcm.server.Message;
import com.google.android.gcm.server.Result;
import com.google.android.gcm.server.Sender;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;


public class MainClass {

    public static void main(String[] args) {
        System.out.println("starting gcm-server Application");
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                init();
            }
        });

    }

    /**
     *  Send Notification to server
     * @param apiKey
     * @param registrationId
     * @param title
     * @param messagetext
     * @return
     */
    public static String send(String apiKey, String registrationId,String title,String messagetext) {
        Sender sender = new Sender(apiKey);
        Result result = null;
        Message message = new Message.Builder()
                .addData("message",messagetext)
                .addData("title", title)
                .build();
        try {
            result = sender.send(message, registrationId, 2);
            System.out.println("Result : " + result.getMessageId());
            System.out.println("Result ErrorCode : " + result.getErrorCodeName());
            System.out.println("Result : " + result.getCanonicalRegistrationId());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result.toString();
    }

    /**
     * Initialize the Swing form
     */
    public static void init() {
        JFrame frame = new JFrame("Notification Sender");
        frame.setSize(600, 400);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JPanel panel = new JPanel();
        frame.add(panel);
        placeComponents(panel);

        frame.setVisible(true);
    }

    /**
     *  Add Items to Swing form
     * @param panel
     */
    private static void placeComponents(JPanel panel) {

        panel.setLayout(null);

        JLabel apiKeyLabel = new JLabel("ApiKey");
        apiKeyLabel.setBounds(50, 20, 100, 40);
        panel.add(apiKeyLabel);

       final JTextField apiKeyText = new JTextField(20);
        apiKeyText.setBounds(160, 20, 400, 40);
        panel.add(apiKeyText);

        JLabel registrationLabel = new JLabel("Registraion ID");
        registrationLabel.setBounds(50, 70, 100, 40);
        panel.add(registrationLabel);

        final JTextField registrationText = new JTextField(20);
        registrationText.setBounds(160, 70, 400, 40);
        panel.add(registrationText);

        JLabel titleLabel = new JLabel("Title :");
        titleLabel.setBounds(50, 120, 100, 40);
        panel.add(titleLabel);

        final JTextField titleText = new JTextField(20);
        titleText.setBounds(160, 120, 400, 40);
        panel.add(titleText);

        JLabel messageLabel = new JLabel("Message :");
        messageLabel.setBounds(50, 170, 100, 40);
        panel.add(messageLabel);

        final JTextField messageText = new JTextField(20);
        messageText.setBounds(160, 170, 400, 40);
        panel.add(messageText);

        JButton resetButton = new JButton("Reset");
        resetButton.setBounds(50, 220, 120, 40);
        panel.add(resetButton);

        JButton sendNotification = new JButton("Send");
        sendNotification.setBounds(250, 220, 120, 40);
        panel.add(sendNotification);

        final JLabel statusLabel = new JLabel("status :");
        statusLabel.setBounds(50, 270, 400, 100);
        panel.add(statusLabel);

        sendNotification.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                statusLabel.setText("");
                String message = messageText.getText();
                String apiKey = apiKeyText.getText();
                String registrationKey = registrationText.getText();
                String titleMessage = titleText.getText();
                if((registrationKey.equals("")||registrationKey.equals(null))||(apiKey.equals("")||apiKey.equals(null))||(message.equals("")||message.equals(null))){
                    statusLabel.setText("Please Fill the above three Fields");
                }else {
                    statusLabel.setText("sending message ...........");
                    String response = send(apiKey,registrationKey,titleMessage,message);
                    statusLabel.setText(response);
                }

            }
        });

        resetButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                statusLabel.setText("");
                messageText.setText("");
                apiKeyText.setText("");
                registrationText.setText("");
                titleText.setText("");
            }
        });

    }


}

For use this application you need API key which provided when creating application in Google could platform and registration Id.In the next post I will share simple android client application and how to test using this server.

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