Validate a text file based on LINQ

UI.JPG

Introduction

This article will introduce how to validate a text file based on LINQ.

Background

A flat file is being used as the data file to pass around. In order to make the file to be accepted from other systems, the file has to follow some data format that the other systems expect. Not only the data format, some business rules may also need to be pre-evaluated before the file is sent out. In this article, I'll build a validation engine based on LINQ to a text file to challenge if the file meets all the requirements which I defined for a system to process it.

Rules need to be validated

The valid file should have a HEADER record, a FOOTER record, and some CONTENT records. The first 3 characters will be used to describe the type of record it is. In this case, I am going to use 111 for HEADER record, 999 for FOOTER record, and 222 for CONTENT records. We could use 4-6 characters to describe the sub-record information. However, I am only going to demo the HEADER, FOOTER, and CONTENT records here. File example:

111this is header record
222allen.y.w#gmail.com 123-45-6789 222allen.y.w4gmail.com 123456789 222allen.y.w@gmail.com 123-45-6789 999totalrecord5

In the above file, here are some basic rules I want to validate:

  1. File needs to have a HEADER record, which has a fixed length (16) --> raise error message when not met.
  2. File needs to have one or many CONTENT records, which has a fixed length (40) --> raise error message when not met.
  3. Position starting from 4 to 23 from CONTENT record is used for email information, and it needs to follow the email format (xxx@xxx.xxx) --> raise warning when not met.
  4. Position starting from 24 to 40 from CONTENT record is used for SSN information, and it need to be like: xxx-xx-xxxx (x is number only) -> raise warning when not met.
  5. File needs to have a FOOTER record. --> raise error message when not met.

Validation engine classes

Since the validation engine needs to validate multiple text file formats, I am going create an abstract class (BaseValidator) to structure the basic functionality. A child class (File1Validator) will implement those methods based on it own rules. An Event Handler in BaseValidator will handle the information passed through to the client when an error occurs.

Diagram class:

ClassDiagram.JPG

Validation engine implementation

BaseValidator

BaseValidator is an abstract class. It has a Validate() method that drives all the validating process. In this case, it will always execute the ValidateHeader(), ValidateContent(), and ValidateFooter() processes when we invoke Validate(). The Validate() method can be overridden from the child class to implement more processes.


See full detail: http://www.codeproject.com/KB/files/RulesValidation.aspx

Comments

Post a Comment

Popular posts from this blog

Asynchronous Socket Programming in C#

Image
Objective The objective of this article is to demonstrate a socket-based client/server application that will allow two-way asynchronous communication between a server and multiple client applications. Because this example uses asynchronous methods, the server application does not use threads to communicate to multiple clients (although internally the asynchronous communication mechanism uses threads at the OS level). The Difference Between Synchronous and Asynchronous Communication in Network Programming The key difference between synchronous and asynchronous communication can be explained with an example. Consider a server application that is listening on a specific port to get data from clients. In synchronous receiving, while the server is waiting to receive data from a client, if the stream is empty the main thread will block until the request for data is satisfied. Hence, the server cannot do anything else until it receives data from the client. If another clien
Read more

Url Routing MVC TUTORIAL

Image
This tutorial covers an introduction to the MVC pattern using Visual Basic. It also includes a brief overview of the URL routing assumptions that are a foundation to the implementation of the pattern. A sample application is created to demonstrate the fundamentals of this new web-application model. Implementing business rules and testing is also covered. Finally, the use of two alternative view engines, Silverlight and XML Literals, is coverd.
Read more

WCF Chat Sample

Image
The Chat sample demonstrates how to implement a multiparty chat application by using PeerChannel. Messages sent by any instance of a chat application are received by all other instances. To get samples and instructions for installing them Do one or more of the following: On the Help menu, click Samples . The Readme displays information about samples. Visit the Visual Studio 2008 Samples Web site. The most recent versions of samples are available there. Locate samples on the computer on which Visual Studio is installed. By default, samples and a Readme file are installed in drive :\Program Files\Microsoft Visual Studio 9.0\Samples\ lcid . For Express editions of Visual Studio, all samples are located online. For more information, see Locating Sample Files . Security Note: This sample code is intended to illustrate a concept, and it shows only the code that is relevant to that concept. It may not meet the security requirements for a specific environment, a
Read more