Lecture 5: Component-based Programming

2 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-2 Objectives “Components are another term for classes, DLLs, and assemblies. Component-based programming is the logical tendency to design our programs as a set of components instead of a large monolithic app. Given the design of.NET and its Framework Class Library, J# programming is inherently component-based programming... ” In 3 Parts: 1.Component-based programming 2.Working with.NET components 3.Creating your own.NET components

3 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-3 Part 1 Component-based programming…

4 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-4 Component-based programming OO programming is component-based programming –classes are components.NET programming is component-based programming –DLLs are components Other components you'll use: –Supplemental UI Library

5 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-5.NET components.NET components must be installed to run a.NET program –in fact, CLR + FxCL must be installed –these are known collectively as the.NET Framework Hardware Operating System Common Language Runtime (CLR).NET program.NET Framework Class Library (FxCL).NET Framework

6 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-6 Installing.NET Framework.NET Framework is installed as part of Visual Studio.NET How to install on systems without VS.NET? Pre-installed on Windows 2003 and above Otherwise you must install 2 pieces of software, in this order: 1..NET Framework 1.1 Redistributable :dotnetfx.exe (20MB) 2.Visual J#.NET Version 1.1 Redistributable :vjredist.exe (7MB) Requirements: –Windows 98 or above

7 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-7 Installing.NET Framework (cont'd) Installing.NET Framework 1.1 Redistributable : – –also available via Windows Update (IE, Tools menu, recommended) Installing Visual J#.NET Version 1.1 Redistributable : – Other components are installed on an "as-needed" basis Supplemental UI Library: –see

8 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-8 Part 2 Working with.NET components…

9 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-9 Programming options J# programming can really be done at two levels: 1.using Visual Studio.NET 2.at the command-line, much like Sun's JDK Let's use the command-line tools since it's easier to understand how.NET component work…

10 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-10 Command-line development Main tools: –vjc :Visual J# compiler –notepad :simple Windows text editor (any editor will do) How to get started? –open Visual Studio.NET 2003 Command Prompt Start menu, All Programs, Microsoft Visual Studio.NET 2003, Visual Studio.NET Tools, Visual Studio.NET 2003 Command Prompt

11 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-11 Example Let's create a simple GUI app using the Java Class Library –in particular, using the SWING classes of the JCL GUIApp : –outputs "ouch!" to the console each time you click the button… C:\GUIApp> guiapp.exe ouch!

12 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-12 GUIApp GUIApp is a single source code file "GUIApp.jsl": public class GUIApp { public static void main(String[] args) { javax.swing.JFrame frame = new javax.swing.JFrame(); java.awt.Container c = frame.getContentPane(); javax.swing.JButton button1 = new javax.swing.JButton("Click Me"); frame.setSize(100, 100); frame.setLocation(100, 100); frame.setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); c.add(button1); button1.addActionListener(new ButtonHandler()); frame.show(); } } //class class ButtonHandler implements java.awt.event.ActionListener { public void actionPerformed(java.awt.event.ActionEvent e) { System.out.println("ouch!"); } } //class public class GUIApp { public static void main(String[] args) { javax.swing.JFrame frame = new javax.swing.JFrame(); java.awt.Container c = frame.getContentPane(); javax.swing.JButton button1 = new javax.swing.JButton("Click Me"); frame.setSize(100, 100); frame.setLocation(100, 100); frame.setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); c.add(button1); button1.addActionListener(new ButtonHandler()); frame.show(); } } //class class ButtonHandler implements java.awt.event.ActionListener { public void actionPerformed(java.awt.event.ActionEvent e) { System.out.println("ouch!"); } } //class

13 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-13 Compilation Compile using the Visual J# compiler "vjc" –reference Supplemental UI Library to use SWING –compiler switches: /t:build a console-based.EXE /r:reference the specified.NET component (.DLL) C:\GUIApp> dir 04/20/ GUIApp.jsl C:\GUIApp> vjc /t:exe GUIApp.jsl /r:vjssupuilib.dll Microsoft (R) Visual J#.NET Compiler version For Microsoft (R).NET Framework version Copyright... C:\GUIApp> dir 04/20/200420,480GUIApp.exe

14 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-14 Run! Run the.EXE from the command-line: C:\GUIApp> guiapp.exe ouch!

15 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-15.NET Framework SDK.NET Framework SDK contains the command-line tools –SDK = Software Development Kit –.NET equivalent of Sun's JDK –installed as part of Visual Studio.NET –available separately as a free download (100MB):

16 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-16 Issues with using Swing Advantage of using Swing: You can recompile without modification usings Sun’s JDK and run on any Java platform. Disadvantage of using Swing: Swing programming by hand is hard and tedious and does not let you take full advantage of the Visual Studio integrated IDE.

17 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-17 Example #2 A better example of SWING –Visual Sorting demo… public VisualSorting() { super("VisualSorting"); URL u = VisualSorting.class.getResource("Random.jpg"); icon= new ImageIcon(u); // create AlgorithmPanels, and the mainControlPanel populateAlgorithmsPane(); mainControlPanel = new MainControlPanel (this); // add the algorithmPanel, and mainControlPanel to the contentPanel getContentPane().setLayout (new GridBagLayout()); GridBagConstraints gConstraints = new GridBagConstraints(); gConstraints.anchor = GridBagConstraints.CENTER; gConstraints.fill = GridBagConstraints.BOTH; gConstraints.gridx = GridBagConstraints.RELATIVE; gConstraints.gridy = GridBagConstraints.RELATIVE; gConstraints.gridwidth = GridBagConstraints.REMAINDER; gConstraints.gridheight = 650;. public VisualSorting() { super("VisualSorting"); URL u = VisualSorting.class.getResource("Random.jpg"); icon= new ImageIcon(u); // create AlgorithmPanels, and the mainControlPanel populateAlgorithmsPane(); mainControlPanel = new MainControlPanel (this); // add the algorithmPanel, and mainControlPanel to the contentPanel getContentPane().setLayout (new GridBagLayout()); GridBagConstraints gConstraints = new GridBagConstraints(); gConstraints.anchor = GridBagConstraints.CENTER; gConstraints.fill = GridBagConstraints.BOTH; gConstraints.gridx = GridBagConstraints.RELATIVE; gConstraints.gridy = GridBagConstraints.RELATIVE; gConstraints.gridwidth = GridBagConstraints.REMAINDER; gConstraints.gridheight = 650;. public static void main(String args[]) { VisualSorting sd = new VisualSorting(); sd.setSize((int) (520 * 1.61), 520); sd.setResizable(false); sd.reset(); sd.show(); } public static void main(String args[]) { VisualSorting sd = new VisualSorting(); sd.setSize((int) (520 * 1.61), 520); sd.setResizable(false); sd.reset(); sd.show(); }

18 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-18 Part 3 Creating your own.NET components…

19 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-19 Motivation Professionals create their own components for many reasons: –Team programming: each builds their own component and tests separately. –Multi-language programming: components in different languages are built (e.g. VB, J#, C++) and then integrated. –Component reuse –Component updating: Components can be updated independently to fix bugs

20 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-20 Example: N-Tier design Business applications commonly follow an N-Tier design –application is logically divided by task areas –physically built as a set of components Business.dll Presentation Tier Data Access Tier e.g. read and write from customer files or database Data Tier e.g. data source, like files or database Business Logic Tier e.g. purchase products or pay employees GUI.exe DataAccess.dll

21 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-21 Component-based BankingApp Let's rebuild the BankingApp as a set of components: transactions.txt customers.txt App.jsl Customer.jsl CustomersIO.jsl Transactions.jsl Transactions.dll BankingApp.exe Customers.dll

22 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-22 (1) Customers.dll First, build the lower-level data access tier, Customers.dll : –in this case we target (/t:) a library, not an exe –Rather than /t:library we can abbreviate to /t:l C:\BankingApp> dir *.jsl 04/20/20041,039App.jsl 04/20/ Customer.jsl 04/20/20041,603CustomersIO.jsl 04/20/20041,443Transactions.jsl C:\BankingApp> vjc /t:library Customer.jsl CustomersIO.jsl /out:Custo mers.dll Microsoft (R) Visual J#.NET Compiler version For Microsoft (R).NET Framework version Copyright... C:\BankingApp> dir *.dll 04/20/200420,480Customers.dll

23 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-23 (2) Transactions.dll Second, build the middle-level business tier, Transactions.dll : –reference Customers.dll to gain access to definition of Customer C:\BankingApp> dir *.jsl 04/20/20041,039App.jsl 04/20/ Customer.jsl 04/20/20041,603CustomersIO.jsl 04/20/20041,443Transactions.jsl C:\BankingApp> vjc /t:library Transactions.jsl /r:Customers.dll /out:Trans actions.dll Microsoft (R) Visual J#.NET Compiler version For Microsoft (R).NET Framework version Copyright... C:\BankingApp> dir *.dll 04/20/200420,480Customers.dll 04/20/ Transactions.dll

24 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-24 (3) BankingApp.exe Third, build the presentation tier.EXE, BankingApp.exe : –references both Customers.dll and Transactions.dll C:\BankingApp> dir *.jsl 04/20/20041,039App.jsl 04/20/ Customer.jsl 04/20/20041,603CustomersIO.jsl 04/20/20041,443Transactions.jsl C:\BankingApp> vjc /t:exe App.jsl /r:Customers.dll /r:Transactions.dll /out:Ba nkingApp.exe Microsoft (R) Visual J#.NET Compiler version For Microsoft (R).NET Framework version Copyright... C:\BankingApp> dir *.dll;*.exe 04/20/200420,480Customers.dll 04/20/ Transactions.dll 04/20/200420,480BankingApp.exe

25 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-25 Run! BankingApp runs exactly as before…

26 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-26 If.NET can't find component? If a referenced.DLL cannot be found, program fails to run… Example: –move Customers.dll out of folder, and try running app… move to desktop…

27 MicrosoftIntroducing CS using.NETJ# in Visual Studio.NET 5-27 Summary.NET is built using component-based programming J# programming is component-based programming Professional programming is component-based programming