.net barcode Figure 8-23. The client with the new version of Person calling the intermediary in VB.NET

Creation Denso QR Bar Code in VB.NET Figure 8-23. The client with the new version of Person calling the intermediary

Figure 8-23. The client with the new version of Person calling the intermediary
QR Code Generator In Visual Basic .NET
Using Barcode printer for .NET Control to generate, create Quick Response Code image in .NET applications.
www.OnBarcode.com
QR Reader In VB.NET
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
CHAPTER 8 THE INS AND OUTS OF VERSIONING
Making Code-39 In VB.NET
Using Barcode generator for .NET framework Control to generate, create Code 39 Extended image in .NET framework applications.
www.OnBarcode.com
UCC.EAN - 128 Generation In VB.NET
Using Barcode generation for VS .NET Control to generate, create UCC-128 image in VS .NET applications.
www.OnBarcode.com
Figure 8-24. The intermediary retrieving and sending messages of the old version
Barcode Printer In VB.NET
Using Barcode maker for .NET framework Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
PDF417 Creator In VB.NET
Using Barcode creator for .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
www.OnBarcode.com
Figure 8-25. The server with the new version of Person called from the intermediary
Make Linear In VB.NET
Using Barcode generator for VS .NET Control to generate, create Linear 1D Barcode image in .NET applications.
www.OnBarcode.com
Painting GTIN - 14 In Visual Basic .NET
Using Barcode generation for VS .NET Control to generate, create EAN / UCC - 14 image in .NET framework applications.
www.OnBarcode.com
Note To make the flow between the three participants with different versions of the message possible,
QR Code Decoder In VB.NET
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
QR Code 2d Barcode Encoder In Visual Basic .NET
Using Barcode maker for .NET Control to generate, create Quick Response Code image in VS .NET applications.
www.OnBarcode.com
I had to configure the option includeVersions="false" for all three participants. If this option is configured to true, you would get an exception either in the intermediary or in your client and server. The reason is that the runtime tries to bind serialized data always to its original version of the type. This means if your client serializes version 2.0 of Person, then the serialization runtime tries to find version 2.0 on the intermediary. But the intermediary doesn t know anything about version 2.0, and therefore the runtime throws an exception. And even if the intermediary knows about the type (for example, because it is installed in GAC), you would get an exception because the intermediary is not built for using the newer version.
Draw EAN13 In None
Using Barcode printer for Office Excel Control to generate, create UPC - 13 image in Office Excel applications.
www.OnBarcode.com
Create Barcode In None
Using Barcode generation for Excel Control to generate, create Barcode image in Excel applications.
www.OnBarcode.com
Now you ve seen the problem. The comment as well as the birth date are lost (take a look at the output no comment and an empty default date). But how can you solve it Well, the preceding sample is a typical example of having not known the versioning requirements for the application and therefore implementing a simplistic versioning strategy. The only way to fix this problem is fixing both version 1 and version 2 of the shared assembly. So what you have to do is step back to your original version version 1 of the client, the intermediary, and the back-end server and restart your implementation again. The requirements of the original scenario say that messages must be able to be sent to intermediaries not understanding the newer version without losing any data. Therefore, you have to implement your very first version of Person with that in mind. If the first version retrieves information from the serialization stream that it doesn t understand, it has to still keep this information. The changed implementation of your first version for Person looks like the code in Listing 8-18.
Barcode Generation In None
Using Barcode drawer for Software Control to generate, create Barcode image in Software applications.
www.OnBarcode.com
Barcode Generator In Visual Studio .NET
Using Barcode creator for Reporting Service Control to generate, create Barcode image in Reporting Service applications.
www.OnBarcode.com
CHAPTER 8 THE INS AND OUTS OF VERSIONING
Code 39 Full ASCII Decoder In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Encoding PDF417 In Java
Using Barcode encoder for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Listing 8-18. The New Shared Assembly for the First Version using using using using using System; System.Collections; System.Reflection; System.Runtime.Serialization; System.Runtime.CompilerServices;
Printing Barcode In C#
Using Barcode printer for Visual Studio .NET Control to generate, create Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
GTIN - 12 Creation In None
Using Barcode creation for Online Control to generate, create GS1 - 12 image in Online applications.
www.OnBarcode.com
[assembly: AssemblyTitle("Shared Assembly")] [assembly: AssemblyVersion("1.0.0.20")] [assembly: AssemblyKeyFile(@"..\..\..\Server.snk")] namespace General { public interface IRemoteFactory { int GetAge(); Person GetPerson(); void UploadPerson(Person p); } [Serializable] public class Person : ISerializable { public int Age; public string Firstname; public string Lastname; private ArrayList Reserved=null; public Person(string first, string last, int age) { this.Age = age; this.Firstname = first; this.Lastname = last; } public Person(SerializationInfo info, StreamingContext context) { ArrayList values = (ArrayList)info.GetValue( "personData", typeof(ArrayList)); this.Age = (int)values[0]; this.Firstname = (string)values[1]; this.Lastname = (string)values[2]; Console.WriteLine("[Person]: Deserialized person: {0} {1} {2}", Firstname, Lastname, Age);
Scanning Barcode In Java
Using Barcode Control SDK for Java Control to generate, create, read, scan barcode image in Java applications.
www.OnBarcode.com
GS1 - 12 Decoder In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
CHAPTER 8 THE INS AND OUTS OF VERSIONING
if(values.Count > 3) { Console.WriteLine("[Person]: Found additional values..."); Reserved = new ArrayList(); for(int i=3; i < values.Count; i++) Reserved.Add(values[i]); Console.WriteLine("[Person]: Additional values saved!"); } } public void GetObjectData(SerializationInfo info, StreamingContext context) { ArrayList data = new ArrayList(); Console.WriteLine("[Person]: serializing data..."); data.Add(Age); data.Add(Firstname); data.Add(Lastname); if(Reserved != null) { Console.WriteLine("[Person]: storing unknown data..."); foreach(object obj in Reserved) data.Add(obj); } info.AddValue("personData", data, typeof(ArrayList)); } } } As you can see in this listing, you need to change the custom serialization and deserialization quite heavily. Now the Person uses an ArrayList for storing its own data as well as additional data. All data objects that are not understood bye the Person class are stored in a private object array Reserved. More exactly, in the special constructor of the Person class, all information understood by this version is read from the ArrayList stored in the SerializationInfo and directly assigned to the Person s members. If there is any further information present, it will be stored in a private object array called Reserved. If the runtime serializes the Person object by calling the ISerializable.GetObjectData() method, it serializes its own data at first and then if present any data from the reserved field (which is not understood by this version), too. Therefore, you don t lose any data when a newer version introduces additional fields.
Copyright © OnBarcode.com . All rights reserved.