Creating a new application

Our tutorial application will consist of two parts:

  1. Java code: We’ll create a controller (in reality you might need to create many, depending on how complex your application is) that will handle many of our web requests. Most importantly, it will handle the top-level access request.
  2. Web code: The web code consists of all the files that Tomcat serves when requests are made for our application. Files like HTML, CSS, JavaScript, images, and so on.

If you’re working with code command-line only (e.g. vim), you’ll want to create symlinks to both parts of the code, java and web. While debugging, you’ll frequently move between the two halves.

Java code location

Our Java code will reside here:

sdk/ecomp-sdk/epsdk-app-os/src/main/java/org/openecomp/myapp

Create the myapp directory.

Web code location

Our web code will reside here:

sdk/ecomp-sdk/epsdk-app-os/src/main/webapp/app/fusion/scripts/myapp

Create the myapp directory.

Inside this directory, we’ll add our first subpage:

sdk/ecomp-sdk/epsdk-app-os/src/main/webapp/app/fusion/scripts/myapp/myfirstpage

Create the myfirstpage directory.

Spring controllers

We need a controller to handle the top-level access requests (e.g. localhost:8080/epsdk-app-os/somepage). For every somepage our app needs, we’ll need to either designate an existing controller to handle the request or create a new one.

Why would you need to create a new one?

The controller is where you’ll set up your database access, read from database tables, update database tables, and so on. It may make sense to use different controllers for different somepage functions to increase readability and make things easier when others need to maintain the code.

A basic controller

Copy the following basic controller code into your Java code location as MyAppController.java

package org.onap.myapp;

import java.util.HashMap;
import java.util.ArrayList;
import java.util.Map;
import java.util.List;
import java.io.IOException;

import java.beans.PropertyVetoException;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.stereotype.Repository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.jdbc.core.JdbcTemplate;

import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
import javax.annotation.PostConstruct;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import org.json.JSONObject;
import org.json.JSONArray;

import org.onap.portalsdk.core.controller.RestrictedBaseController;
import org.onap.portalsdk.core.util.SystemProperties;
import org.onap.portalsdk.core.domain.User;

@Controller
@Repository
@RequestMapping("/")
public class MyAppController extends RestrictedBaseController {
  ///////////////////////////////////////////////////////////////////////////////
  // Constructor
  //
  public MyAppController() {
    super();
  }

  ///////////////////////////////////////////////////////////////////////////////
  // Handle 'myfirstpage' requests
  //
  @RequestMapping(value = { "/myfirstpage" }, method = RequestMethod.GET)
  public ModelAndView myfirstpage(HttpServletRequest request) {
    final String defaultViewName = null;
    return new ModelAndView(defaultViewName);
  }
}

Request routing via definitions.xml

In order for the framework to route requests for myfirstpage correctly, we’ll need to create an entry in sdk/ecomp-sdk/epsdk-app-os/src/main/webapp/WEB-INF/defs/definitions.xml that looks like this:

<definition name="myfirstpage" template="/app/fusion/scripts/myapp/myfirstpage/myfirstpage.html" />

Then, add the following to sdk/ecomp-sdk/epsdk-app-os/src/main/webapp/app/fusion/scripts/myapp/myfirstpage/myfirstpage.html:

<html>
  <body>
    <p>It worked!</p>
  </body>
</html>

Now, build and install your application as before. If everything worked, you should see It worked! in your browser window when you visit myfirstpage after logging in.

When the request from the browser comes in, the framework creates a mapping from myfirstpage to the MyAppController, which in turn maps your definition name to a particular template. Soon, we’ll fill in that template to do more interesting things.