Chapter 12 Microsoft Assemblies

Process Phases Discussed in This Chapter Requirements Analysis Design Implementation ArchitectureFramework Detailed Design x Key:= secondary emphasis x = main emphasis Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Learning Goals for This Chapter  … Microsoft’s component (“assembly”) architecture  … where assemblies fit in.NET  … required rudiments of C#  … the contents of.NET manifests, including: Versioning Attributes  … the difference between private and shared assemblies  … create assemblies using C# Understand … Be able to … Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

.NET Goals and Solutions  Create interoperable components from multiple source languages o C++, Visual Basic, ….  Solve multiple component version clashes o “dll hell”: naming confusion in COM  Define a common runtime  Avoid registry o Necessity to register components with host computer Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Design Goal At Work:  Reusability  Microsoft wanted to allow developers to create interoperable components using their favorite source languages. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

The Parts of.NET Web tools and Languages ASP.NET, Windows Forms; Visual Basic.NET, C#.NET Framework Classes net XMLIO Security.. Common Language Runtime (CLR) Memory ManagementCommon Type System (CTS).. uses Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

 Boolean  DateTime  Decimal – 28 significant digits  Double – 64-bit double-precision floating point  GUID – unique 128-bit integer; unique identifier  Int16, Int32, Int64  Sbyte – 8-bit signed integer –128 to +127  Single – 4-byte single precision floating point  TimeSpan – a period of time Types in the CTS Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

 Boolean Equals( Object )  Int32 GetHashCode() o Generates an integer corresponding to the value of the object o Used by sorting algorithms in System.Collections  Type GetType() o for the Reflection API  String ToString() Methods of System.Object Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Selected System.XX.NET Framework NameSpaces  Collections  ComponentModel o “to implement the runtime and design time behavior of components”  Data o To deal with databases via ADO  Drawing  IO  Net o to interface with common network protocols  Reflection  Runtime  Security  Text o ASII, Unicode etc.  Threading  Web  WinForms  XML Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Compilation Process in.NET Source Code C++ VB Compiler & metadata generator IL and metadata Ancillary info.dll or.exe Base class library Class loader IL compiler native code execute Process File Key: C# J#, Java (3 rd parties) Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

A File The Parts of a.NET Assembly (Component) Manifest o Identity o name o version o Names of files o Encrypted hash of files to ensure integrity o Specification of types defined o Names of referenced assemblies o Specification of required security permissions Microsoft Intermediate Language (IL) Source FilesA.NET assembly: xyz.dll Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Key Concept:  A.NET Assembly  -- includes class code from multiple files, in IL form, described by a manifest. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

C# Goals 1 of 2 o Rapid application development o as with JavaBeans o Cross-platform deployment o generates character stream interpreted by.Net runtime. o as with Java Virtual Machine o Access to platform-native resources o take advantage of the Windows API to run as a full- featured application on Windows 2000 o Support for the COM and.NET platforms Unlike Java Unlike Java Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

 Features of C and C++ “with the functional ease of rapid application development tools.”  Components with properties, methods and events o built in C# Goals : 2 of 2 Unlike Java Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

HelloWorld Output Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Selected C# Features o Automatic garbage collection o Allows developers to disable garbage collection locally – o by marking code as “unsafe” o (e.g., where real time performance required?) o Eliminates pointers in favor of references o Introduces Interfaces Unlike Java Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

C# Web Features: Web Services  Attribute library allows wrapping of C# classes and functions as Web services. o a hosted software module callable over the Internet typically via SOAP protocol. o SOAP wraps method calls, parameters, and return values, in XML packets.  Using appropriate attributes, programmer can turn any C# class or function into a Web service. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Creating a.NET Component 1 of 2 csc /t:library /out:hello.dll helloFile.cs “target” Create a library component: Don’t seek Main() “output” Component (output) name Input fileC# compilation Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Creating a.NET Component (“Assembly”) 2 of 2 helloFile.cs hello.dll csc /t:library /out:hello.dll helloFile.cs Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Using a.NET Component csc /r:hello.dll /out:helloApp.exe helloClient.cs hello.dllhelloClient.cs helloApp.exe … now execute helloApp. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Creating a.NET Component Containing Multiple Classes csc /t:library /out:helloAuRevoir.dll HelloAuRevoirComponentSource.cs helloAuRevoir.dll GreetingUtilityHelloClassAuRevoirClass Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Output For “Multiple Class” Example Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Using metadata allows the CLR to support:  Multiple execution models o interpreted, o JITted (Just-in-time) o native o legacy code (prior to.NET)  Uniform services available to debuggers, profilers etc.  Consistent exception handling  Code access security  Memory management  Reflection  Interoperability with existing unmanaged COM applications  Interoperability with existing unmanaged code  Optimization to match the particular CPU or environment. Uses for Metadata Amended from Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Manifest of Component helloAuRevoir.dll Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Manifest Contents for helloAuRevoir.dll Component Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Manifest Detail of sayHelloWorld() in HelloClass Recall the source: public void SayHelloWorld( ) {GreetingUtility.OutputMessage ( "Component says: Hello World" ); } Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

The Version Field of an Assembly o Major version o Minor version o Revision o Build number Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Versioning (The process of evolving a component over time in a compatible manner.) A new version is …  … source compatible with a previous version if code that depends on the previous version can, when recompiled, work with the new version.  … binary compatible if code that depended on the old version can, without recompilation, work with the new version.” (adapted from Microsoft) Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Attribute s in.NET  Metadata: about … o … variables o … classes o … functions  Types of attributes: o Built-in o User-defined  Available at runtime Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Output of main() in ConditionalDemo with #define DEBUG without #define DEBUG Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Output For Authorship Querying Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Key Concept:  A.NET Manifest Lists … .. the files containing the IL-compiled classes, the.NET components on which the assembly depends, version numbers, attributes, and encrypted hash to verify not tampered in transit. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Design Goal At Work:  Reusability  We want to reuse an assembly, confident it is the one it’s supposed to be. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Using NameSpaces Application 1 : List available flights in following form From to departing at and arriving at. Application 2: List bookings already made in following form Please arrive at at airport for your flight. Implement applications 1and 2. Exploit common components. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Namespaces Across Multiple Components Logo AvailabilityAnnouncement Itinerary namespace (Physical) File organization (3 files) Airlines namespace Namespace stated: Airlines.Availability Classes: Logo, AvailabilityAnnouncement Availability namespace ItineraryAnnouncement Logo (Logical) Namespace organization Source file name: AvailabilityComponentSource.cs Component name: availability.dll Namespace stated: Airlines.Itinerary Class: Logo Source file name: ItineraryLogoComponentSource.cs Component name: itineraryLogo.dll Namespace stated: Airlines.Itinerary Class: ItineraryAnnouncement Source file name: ItineraryAnnouncement.cs Component name: itineraryAnnouncmnt.dll Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Airline Reservation System Display Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Public Key Cryptography o Any message encoded with one key can be decoded with the other. o One can’t encrypt and decrypt a message with the same key. o It’s practically impossible to deduce one key from the other. o It’s very unlikely that an encoded document can be decoded with an unmatched key Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Public Key Encryption Used in.NET Public key: …iemhdZX… Private key: …92JiuHKM3… (secret) myKeys.snk Hashed versionEncoded version use private key Manifest Names & contents of assembly Verification process AssemblyInfo.cs Assembly source assembly hash OK / not OK Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Key Concept:  Component Identity  To ensure that the component we are using is the one intended, we use relatively or globally unique names:.NET also applies tamper-proofing via public key encryption. Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.

Summary  Microsoft “assembly” == component  Microsoft distributes computing among desktops and servers via, in part,.NET assemblies .NET assemblies supercede and are more versatile than (D)COM(+) objects. o Exist in Intermediate Language o Permit versioning o Include “attribute” feature o Identity technique for shared assemblies reduces “dll hell”  C# language designed for.NET  Assemblies constructed via C#, VB,... are interoperable Adapted from Software Design: From Programming to Architecture by Eric J. Braude (Wiley 2003), with permission.