Big Data Integration

Module Information

Module Objectives

• How to implement a cloud based storage solution for a company's big data needs
• The knowledge needed to integrate desktop and web applications to utilize web services and stored data.
• How cloud based DNS solutions can help to optimize a company's IT infrastructure
• How cloud based servers and service implementations can be easily deployed for rapid utilisation
• The steps involved in data exchange between web services and cloud based applications

Resources - References

• Programming Amazon EC2, Juirg van Vliet 1st 2011 O’Reilly
• Google Compute Engine, Marc Cohen 1st 2011 O’Reilly
• Python for Google App Engine, Massimiliano Pippi 1st 2015 Packet
• Big Data Fundamentals Concepts, Drivers & Techniques, Thomas Erl, Wajid Khattak, and Paul Buhler, Prentice Hall

Service-Oriented Architecture (SOA)

• A service-oriented architecture (SOA) is a style of software design where services are provided to the other components by application components, through a communication protocol over a network.

• A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online.

• SOA provides access to reusable Web services over a TCP/IP network,

Web service

• A software component stored on one computer that can be accessed via method calls by an application (or other software component) on another computer over a network

• Web services communicate using such technologies as:
  • XML, JSON and HTTP
  • Simple Object Access Protocol (SOAP): An XML-based protocol that allows web services and clients to communicate in a platform-independent manner

Basic concepts:

• Remote machine or server: The computer on which a web service resides
• A client application that accesses a web service sends a method call over a network to the remote machine, which processes the call and returns a response over the network to the application
• Publishing (deploying) a web service: Making a web service available to receive client requests.
• Consuming a web service: Using a web service from a client application.
• In Java, a web service is implemented as a class that resides on a server.

An application that consumes a web service (client) needs:

• An object of a proxy class for interacting with the web service.
• The proxy object handles the details of communicating with the web service on the client's behalf

JAX-WS:

• The Java API for XML Web Services (JAX-WS) is a Java programming language API for creating web services, particularly SOAP services. JAX-WS is one of the Java XML programming APIs. It is part of the Java EE platform.
  • Requests to and responses from web services are typically transmitted via SOAP.
  • Any client capable of generating and processing SOAP messages can interact with a web service, regardless of the language in which the web service is written.

Creating - Deploying - Testing and Describing a Web Service using NetBeans

• In Netbeans, you focus on the logic of the web service and let the IDE handle the web service’s infrastructure

• We first need to to do some configuration in NetBeans:
  • Go to /usr/local/netbeans-8.2/etc/netbeans.conf:
    • Find the line: netbeans_default_options
    • If -J-Djavax.xml.accessExternalSchema=all is not between the quotes then paste it in.

• If you are deploying to the GlassFish Server you need to modify the configuration file of the GlassFish Server (domain.xml):
  • /usr/local/glassfish-4.1.1/glassfish/domains/domain1/config/domain.xml
    • Find : <java-config
    • Check the jvm-options for the following configuration: <jvm-options>-Djavax.xml.accessExternalSchema=all</jvm-options>
    • It should be there by default, if not paste it in, save file and exit
    • You can now start Netbeans IDE

• Create a Web Service in NetBeans- Locally
  • Choose File > New Project:
  • Select Web Application from the Java Web category
  • Change Project Name: to CalculatorWSApplication
  • Set the server to GlassFish 4.1.1
  • Set Java EE Version: Java EE 7 Web
  • Set Context path: /CalculatorWSApplication
  • After that you should now have a project created in the Projects view on the left hand side.

• Creating a WS from a Java Class:

• Right-click the CalculatorWSApplication node and choose New > Web Service.

• If the option is not there choose Other > Web Services > Web Service

• Click Next
• Name the web service CalculatorWS and type com.hduser.calculator in Package. Leave Create Web Service from Scratch selected.
• Select Implement Web Service as a Stateless Session Bean.
• Click Finish. The Projects window displays the structure of the new web service and the source code is shown in the editor area. A default hello web service is created by Netbeans.

• Adding an Operation to the WS:

• Change to the Design view in the editor.
• Click the Add operation button.
• In the upper part of the Add Operation dialog box, type add in Name and type int' in the Return Type drop-down list.
• In the lower part of the Add Operation dialog box, click Add and create a parameter of type int named num_1.
• Click Add again and create a parameter of type int called num_2.
• Click OK at the bottom of the panel to add the operation.
• Remove the default hello operation: Right click on hello operation and choose: Remove Operation
• Click on the source view to go back to view the code in the editor.
• You will see the default hello code is gone and the new add method is now there instead.
• Now we have to alter the code to look like this.

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.adelo.calculator;

import javax.jws.WebService;
import javax.jws.WebMethod;
import javax.jws.WebParam;
import javax.ejb.Stateless;

@WebService(serviceName = "CalculatorWS")
@Stateless()
public class CalculatorWS {

    /**
     * Web service operation
     */
    @WebMethod(operationName = "add")
    public int add(@WebParam(name = "num_1") int num_1, @WebParam(name = "num_2") int num_2) {
        //TODO write your implementation code here:
        int result = num_1 + num_2;
        return result;
    }
}

• Well done, you have just created your first Web Service.
• To test the Web service drop down the Web Services directory and right click on CalculatorWSApplication.
• Choose Test Web service.
• Netbeans throws an error: It is letting us know that we have not deployed our Web Service.
• Right click on the main Project node and select deploy

• Testing the WS:

• Deploying the Web Service will automatically start the GlassFish server. Allow the server to start, this will take a little while. You can check the progress by clicking on the GlassFish tab at the bottom of the IDE.
• Wait until you see: «CalculatorWSApplication was successfully deployed in 9,912 milliseconds»
• Now you can right click on the Web Service as before and choose Test Web Service.
• The browser will open and you can now test the Web service and view the WSDL file.
• You can also view the Soap Request and Response.

Consuming the Web Service

From a Web Application project

• Now that we have a web service we need a client to consume it.
• Choose File > New Project
• Select Web Application from the Java Web category
• Name the project CalculatorWSJSPClient
• Leave the server and java version as before and click Finish.

• Expand the Web Pages node under the project node and delete index.html.
• Right-click the Web Pages node and choose New > JSP in the popup menu.
  • If JSP is not available in the popup menu, choose New > Other and select JSP in the Web category of the New File wizard.
• Type index for the name of the JSP file in the New File wizard. Click Finish to create the JSP (Java Server Page)

• Right-click the CalculatorWSJSPClient node and choose New > Web Service Client.
  • If the option is not there choose Other > Web Services > Web Service Client
• Select Project as the WSDL source. Click Browse. Browse to the CalculatorWS web service in the CalculatorWSApplication project. When you have selected the web service, click OK.
• Do not select a package name. Leave this field empty.
• Leave the other settings as default and click Finish.
• The WSDL gets parsed and generates the .java
• The Web Service References directory now contains the add method we created in our web service.
• Drag and drop the add method just below the H1 tags in index.jsp
• The Code will be automatically generated.
• Change the values of num_1 and num_2 to any two numbers e.g. 5 and 5 as per test earlier.
• Remove the TODO line from the catch block of the code and paste in:

out.println("exception" + ex);

If there is an error this will help us identify the problem.

• IMPORTANT Once you close Netbeans you are shutting down your server. If you want to reuse a Web Service you must re-deploy.

• Consuming Live WS:
  • Again we are going to need a client.
  • File > New Project > Java Web > Web Application.
  • This time name it SortClient.
  • Click Next
  • Leave the Server and Java Version settings as before (should be default now)
  • Context path : /SortClient
  • Click Finish

From a Java project

Netbeans 6.5 - 9 and Java EE enable programmers to "publish (deploy)" and/or "consume (client request)" web services

This document provides step-by-step instructions to consume a web service in Java using NetBeans IDE.

In the project, we will invoke a sorting web service through its WSDL link: http://vhost3.cs.rit.edu/SortServ/Service.svc?singleWsdl

• Step 1 - Createa JavaProject:
  • We are going to name it: SortClient

• Step 2 - Generate a Web Service Client:
  • After the Java Project has been created, go to the Project Tree Structure, Right click on Project and select New and then choose Web Service Client.
  • Specify the WSDL URL as: http://vhost3.cs.rit.edu/SortServ/Service.svc?singleWsdl
  • Click Finish

• Step 3 - Invoke the Service:
  • Expand the Web Service References until you see the operation lists. Drag the operation you want to invoke to the source code window, such as "GetKey". A piece of code is automatically generated to invoke that operation.
  • Drag MergeSort to the source code window and the corresponding code is automatically generated,too.
  • In the main function, add the code to call the two functions: getKey() and mergeSort();As it is a call to a remote service, RemoteException needs to be listed in the throws cause