Using Eclipse and Java - NSL (Library <V3.2)

Introduction

This article shows you how to use a Java graphical example project, created and designed to be run within the Eclipse IDE, as the basis for adding Zentitle Licensing to your own Java application.

This is a simple way to use NSL in a cross-platform Java application with a graphical user interface using the popular Eclipse IDE and the WindowBuilder Pro GUI designer. Both of these third-party tools are free and download/installation instructions are given below. 

Getting Started with Eclipse

Eclipse is a fully-featured, popular and well-supported

IDE for Java application development. With appropriate plug-ins, it is well-suited to the development of Java applications with a GUI. Eclipse is available for most common computer operating systems. Here we will go through the steps required to install and correctly configure Eclipse for our purposes. For definiteness, we assume an installation on Microsoft Windows x86. Some steps of the procedure may differ on other platforms.

 Download Eclipse for your chosen platform.

• Go to: https://www.eclipse.org/downloads

• Download the version of Eclipse IDE for Java Developers for your chosen platform.

• Install Eclipse by extracting the 'eclipse' folder and its contents to a suitable location (e.g. C:\Program Files (x86).)
• Locate eclipse.exe within the 'eclipse' folder. Run it.
• Create a workspace folder or select an existing workspace using the dialog shown here:

Install a Java Development Kit

To enable Java development on Eclipse, a suitable Java Development Kit (JDK) must be installed. This includes a Java Runtime Environment (the Java virtual machine upon which Java applications run) together with tools for developing, debugging, and monitoring Java applications. The steps for installing the JDK are as follows:

• Obtain the JDK download (the Java Development Kit appropriate to your operating system and version of Eclipse. x86 or x64.)
• Run the JDK executable. This will present an installation wizard. Choose to install all components (see below)

• Add the $JDK\bin subfolder to the PATH environment variable.

Setup/Install a Java Runtime Environment (JRE)

Installing WindowBuilder Pro

WindowBuilder Pro is an Eclipse plug-in that enables the creation of Java GUI applications. We use components of this, most specifically the Swing GUI widget toolkit, in the creation of the user interfaces for the Java Eclipse project.   

 Install WindowBuilder Pro by going to the link: http://www.eclipse.org/windowbuilder/download.php

• Selecting the Release Version appropriate to your version of Eclipse and follow the subsequent instructions to Install New Software.
• Click the Select All button as shown below and click Next.

• Accept the License Agreement terms and click Finish to perform the installation.
• Restart Eclipse.

Importing the Java Eclipse Project

The Java Eclipse project depends on the Java SDK which must also be built,. All components can be built using the following instructions:

• Download the Java Eclipse project file NSLExampleJavaEclipse.zip and extract it to get the JAR file NSLExample.jar.
• Follow the build instructions for the Java SDK (this is a combined project that includes both NSA/NSL functionality.)
• Run Eclipse.
• On the Eclipse menu, click File->Import->General->Existing Projects Into Workspace and then Next.
• In the Import Projects dialog, click Select archive file, navigate to the JAR file you just saved and make the selections shown here:

• Click Select in the Working Sets panel and select NSL Example as shown in the Select Working Sets dialog shown below.
• Click Finish.

On Eclipse, go to Window->Show View->Package Explorer to bring up the Package Explorer view.

• Right-click the NSLExampleJava\src folder and select from the context menu New->Package.
• In the New Java Package dialog, give this package the name 'Nalpeiron' and click Finish.

From the Java SDK, copy (by dragging and dropping to the Nalpeiron package icon) the following files into the com.nalpeiron.nalplibrary package:

• NALP.java
• nalpError.java
• NSA.java
• NSL.java 

Copy the libraries nalpjava.dll into the folder NSLExampleJava/bin and ShaferFileChck.dll (or their equivalents in Linux/OSX - see SDK documentation) to the folder NSLExampleJava.

The project files may be viewed in the Project Explorer by clicking Window->Show View-Project Explorer in the main Eclipse menu.

Individual source code files (with the .java extension) appear in the package subfolders of NSLExampleJava\src. These may be viewed/edited by clicking them in the Project Explorer.

For those source files containing GUI-based classes, it is advisable that they are edited with the WindowBuilder editor that enables switching between Source and Design views. This may be accomplished by right-clicking on the source file icon in the Project Explorer, and, in the pop-up menu, selecting Open With->WindowBuilder Editor

Set Your java.library.path Variable for the Project

• Right-click NSLExampleJava in the Package Explorer.

• Go to Build Path->Configure Build Path->Java Build-Path.

• Click the Source tab and Expand the NSLExampleJava/src folder.

• Select Native Library Location. Click the Edit button. Click the Workspace button. Navigate to the folder NSLExampleJava/bin.

The installation and configuration of the Java Eclipse project are now complete.

Code Integration Walkthrough

1. Create your Public Class

public class NSLExampleJava
{
    public JFrame AppMainFrame;
    JTextField tfUDF;
    JTextArea textArea;
    JLabel lblComputerID;
    private JTextField tfFeatureCode;
    public Shafer oShafer;
    int ShaferError;
    int customerID; //**** REPLACE WITH YOUR CUSTOMERID 
    int productID; //**** REPLACE WITH YOUR PRODUCTID
    boolean JustExit;
    int i;
    int[] aid;
    int[] fid;
    public String RegData;
    int LicenseStatus;
    public Timer nalptimer;  //Timer to periodically check License
    public boolean FileChckFound;
    public boolean NodeLocked; //If false then license is concurrent
    // These private ints are unique to your product and must
    // be set here to the values corresponding to your product.
    public static int ApplicationTxnID = 0;
    //private int SecurityOffset = 0;
    public int privacy;
    String certReq;

Within your Form Load or Application Initialize Event, add code to call the following functions located in the Shafer.cs (oShafer Object) class:

2. Call your Initialise Method

    /**
     * Launch the System.
     */
    public static void main(String[] args)
    {
        // DllTest();
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                NSLExampleJava window = new NSLExampleJava();
                window.AppMainFrame.setVisible(true);
                
            }
        });
    }
    
    /**
     * Create the System.
     */
    public NSLExampleJava()
    {
        initialize();
        String ComputerID = "";
        ShaferError = 0;
        aid = new int[1];
        fid = new int[1];
        aid[0] = 0;
        fid[0] = 0;
        FileChckFound = false;
        NodeLocked = false;
        privacy = 0;
        DllTest();
        customerID = 3183; //**** REPLACE WITH YOUR CUSTOMERID 
        productID = 100; //**** REPLACE WITH YOUR PRODUCTID
        int SecurityConstantX = 100; //**** REPLACE WITH YOUR Security Constant X
        int SecurityConstantY = 600; //**** REPLACE WITH YOUR Security Constant Y
        int SecurityConstantZ = 400; //**** REPLACE WITH YOUR Security Constant Z

3. Retrieve and Check the License Status

        // Get License Status
        try
        {
            LicenseStatus = oShafer.ShaferNSLGetLicenseStatus();
        }
        catch (nalpError E)
        {
            
            if (E.getErrorCode()!=0)
            {
                ShowError(E, true);
            }
        }

    public void ShowError(nalpError E, Boolean exit)
    {
        if (E.getErrorCode()!=0)
        {
            JOptionPane.showMessageDialog(null, E.getErrorMessage());
            if (exit)
            {
                AppMainFrame.dispose();
            }
        }
    }

4. Additional Security Checks

Then Add security code to check the License Status, if the License status shows the client computer has been backdated then show a message and exit application.

This will give the user the prompt to correct their computer's date and time, before running the application again: 

        // SECURITY: If computer has been BACK Dated to get more time for the
        // trial or Subscription then Exit Application
        if (LicenseStatus == Shafer.LicenseStatus.PROD_BTCOUNTER.getValue())
        {
            JOptionPane.showMessageDialog(null, LicenseStatus);
            AppMainFrame.dispose();
        } 

5. Retrieve License from Server

        //If License Status is negative then try to get license from server
        if (LicenseStatus <= 0)
        {
            LicenseStatus = GetLicenseFromServer(false);
        }
        else
        {
            // Extra security procedure: if license table overwritten on an online system, the license table will refresh itself.
            // Don't try License Refresh if Network LTCO, Daemon doen't allow LTCO Refesh's for security reasons
            if (LicenseStatus != Shafer.LicenseStatus.PROD_NETWORK_LTCO.getValue())
            {
                LicenseStatus = GetLicenseFromServer(true);
            }
        }

    private void ShowLicenseStatus(int LicenseStatus)
    {
        int licensetype = 0;
        int activationtype = 0;
        activationtype=oShafer.ShaferNSLGetActivationType();
        licensetype=oShafer.ShaferNSLGetLicenseType();
        // Clear Down status box
        textArea.setText("");
        textArea.setText(textArea.getText() + "License Type: " + Shafer.GetLicenseType(licensetype) + "\r\n");
        textArea.setText(textArea.getText() +"Activation Type: " + Shafer.GetActivationType(activationtype) + "\r\n");
        int SubscriptionExpiresinSecs = 0;
        String SubscriptionExpiryDate = "";
        // Show info in trial
        if (LicenseStatus == Shafer.LicenseStatus.PROD_INTRIAL.getValue())
        {
            int TrialExpiresinSecs = 0;
            String TrialExpiryDate = "";
            // Get the length left in trial in Seconds
            try
            {
                TrialExpiresinSecs = oShafer.ShaferNSLGetTrialExpSec();
            }
            catch (nalpError E)
            {
                ShowError(E, true);
            }
            // Get the Actual Expiry Date
            try
            {
                TrialExpiryDate += oShafer.ShaferNSLGetTrialExpDate();
            }
            catch (nalpError E)
            {            
                ShowError(E, true);
            }
            textArea.setText("IN TRIAL \r\n");
            textArea.setText(textArea.getText() + "Trial Expires in " + TrialExpiresinSecs + " secs \r\n");
            textArea.setText(textArea.getText() + "Trial Expires " + TrialExpiryDate + "\r\n");
        }
        // Show info Activated with a Subscription period
        if (Shafer.GetLicenseType(licensetype).toLowerCase().contains("subscription"))
        {
            // Get the length left in trial in Seconds
            try
            {
                // Get the length left in trial in Seconds
                SubscriptionExpiresinSecs = oShafer.ShaferNSLGetSubExpSec();
                // Get the Actual Subscription Expiry Date
                SubscriptionExpiryDate = oShafer.ShaferNSLGetSubExpDate();
                textArea.setText(textArea.getText() + "Subscription Expires in " + SubscriptionExpiresinSecs + " secs \r\n");
                textArea.setText(textArea.getText() + "Subscription Expires " + SubscriptionExpiryDate + "\r\n");
                NodeLocked = true;
            }
            catch (nalpError E)
            {
                
                if (E.getErrorCode()==-1089) // If license file corrupt
                {
                    if (LicenseStatus == (int) Shafer.LicenseStatus.PROD_CONCURRENT.getValue())
                    {
                        textArea.setText("ACTIVATED PERPETUAL LICENSE (CONCURRENCY)\r\n");
                    }
                    else
                    {
                        textArea.setText("ACTIVATED PERPETUAL LICENSE \r\n");
                    }
                    NodeLocked = false;
                }
                else
                {
                    // Check for other fatal errors
                    if (E.getErrorCode()!=0)
                    {
                        ShowError(E, true);
                    }
                }
            }
        }
    }

        nalptimer.start();
        ShowLicenseStatus(LicenseStatus);
        // Show ComputerID
        ComputerID = oShafer.ShaferNSLGetComputerID();
        lblComputerID.setText(ComputerID);
    }

	ActionListener Tick = new ActionListener()
 	{
  		public void actionPerformed(ActionEvent event)
 		{
   			timer_Tick();
  		}
 	};

    private void timer_Tick()
	{
		// Get License Status
		try
		{
			LicenseStatus = oShafer.ShaferNSLGetLicenseStatus();
		}
		catch (nalpError E)
		{
            if (E.getErrorCode() != 0 && E.getErrorCode() != -1094) // no license
            {
            	JOptionPane.showMessageDialog(null, E.getErrorMessage());
            	AppMainFrame.dispose();
            }
		}
		finally
		{
		}
		// SECURITY: If computer has been BACK Dated to get more time for
		// the trial or Subscription then Exit System
		if (LicenseStatus == Shafer.LicenseStatus.PROD_BTCOUNTER.getValue())
		{
			JOptionPane.showMessageDialog(null, Shafer.LicenseStatus.getLicenseStatus(LicenseStatus));
			AppMainFrame.dispose();
		}
		// If License Status is negative then try to get license from server
		if (LicenseStatus <= 0)
		{
			LicenseStatus = GetLicenseFromServer(false);
		}
		ShowLicenseStatus(LicenseStatus);
	}
          

8. Setup your ApplicationEnd DLL closure

Please add code to the initialize method to trap the JFrame close event in order to perform some necessary tidying up on the application being closed.

       
	private void initialize()
	{
		AppMainFrame = new JFrame();
		AppMainFrame.addWindowListener(new WindowAdapter()
 		{
			@Override
 				public void windowClosing(WindowEvent e)
				{
   					ExitApplication();
  				}
			@Override
				public void windowClosed(WindowEvent e)
  				{
   					ExitApplication();
  				}
 		});
          

    public void ExitApplication()
    {
        nalptimer.stop();
        if (!JustExit)
        {
            // ON Exit Check to see If concurrency License if so then
            // return the license to the server to achieve concurrency
            try
            {
                LicenseStatus = oShafer.ShaferNSLGetLicenseStatus();
                if (LicenseStatus == 1)
                {
                    NodeLocked = true;
                }
                else
                {
                    NodeLocked = false;
                }
            }
            catch (nalpError E)
            {
                
                if (E.getErrorCode()!=0)
                {
                    ShowError(E, false);
                }
            }
            if (LicenseStatus == (int) Shafer.LicenseStatus.PROD_CONCURRENT.getValue())
            {
                // Return the license to the server to free up the
                // activation for another client
                String LicenseCode = null;
                try
                {
                    LicenseCode = GetLicenseCode();
                }
                catch (IOException e)
                {
                    // TODO Auto-generated catch block
                    JOptionPane.showMessageDialog(null, e.getMessage());
                }
                if (LicenseCode == "")
                {
                    JOptionPane.showMessageDialog(null, "Licensecode is required to return the license");
                }
                try
                {
                    ReturnLicense(true);
                }
                catch (nalpError E)
                {                
                    if (E.getErrorCode()!=0 && E.getErrorCode()!=-1080) // error but not privacy unset
                    {
                        ShowError(E, false);
                    }
                }
            }
        }
        if (FileChckFound)
        {
            try
            {
                oShafer.ShaferNalpLibClose();
            }
            catch (nalpError E)
            {
                if (E.getErrorCode()!=0 && E.getErrorCode()!=-1080) // error but not privacy unset
                {
                    ShowError(E, false);
                }
            }
        }
        System.exit(0);
    }

Build, run and test your application

The project may be run/debugged by clicking the NSLExampleJava icon and selecting Run->Run or Run-Debug from the main Eclipse menu.

Exporting the Java Eclipse project

Here we describe how the Java Eclipse project may be exported for redistribution, as a guide for exporting your own applications with the correct files included.

In Eclipse, go to File->Export. In the Export dialog, select the export destination to be Java->JAR file. Make the selections shown here.



The following minimal set of files should be exported from the following folders:

NSLExampleJava:

• .classpath
• .project
• NSL.manifest
• nsllogo.png

NSLExampleJava\src (default package):

• All files
• Now call the JAR file NSLExample.jar and click Next.
• On the JAR Packaging Options dialog, check to Create a source folder structure and then click Finish.
• If the com.nalpeiron.nalplibrary package is also exported, then there will be no need to separately redistribute the Java SDK. 

You have now seen how Zentitle licensing works within an example application. The next step is to examine the licensing logic of this application in more depth so that you will have a greater understanding of how to implement it within your own application.

Download the Java Example Application

You will need to download both the Java SDK and the Java Eclipse project. You can download the Java SDK from this page.    The Eclipse project can be downloaded from the link below:

Release Notes (Please always check the release notes for the latest updates)