Doing Something Usefulwith Enterprise Library 3.0

Benjamin Day

Level: Intermediate

About the speaker

Owner, Benjamin Day Consulting, Inc.– Email: benday@benday.com– Web: http://www.benday.com– Blog: http://blog.benday.com

Trainer– Visual Studio Team System, Team Foundation

Server Microsoft MVP for C# Microsoft VSTS/TFS Customer Advisory

Council Leader of Beantown.NET INETA User

Group

Agenda

Overview Policy Injection Logging Exception Handling Validation

Why Enterprise Library?

Why not?– Why write and re-write common application

code? Focus on solving the core business

problem Microsoft solved it for you

– Standardized solution– Hooks in nicely with .NET through configs

It’s free http://codeplex.com/entlib

Caching

Security

Data Access Logging

ExceptionHandling

Ent Lib 3.0 – Application Blocks

Plug-inConfig

Helpers & Design

Instrumen-tation

ObjectBuilder

Cryptography

Core

Policy InjectionValidation

http://tinyurl.com/3d8xfw

Data Access Block

Wraps common actions for database access

Handles closing of connections, IDispose calls

Some degree of database independence

Relatively easy to understand

Adopting Enterprise Library

Why is this talk titled“Doing Something Useful…”?

Can be like swimming in the Atlantic at low tide in the spring

What does this have to do with the Data Access Block?

Does it have to be so difficult?

My $0.02 on where begin

Start with the Policy Injection Block– Allows you to defer decisions on other blocks

Configure PIB to use logging– Simple way to debug your configuration

Exception Handling Block– (eat your vegetables)

Caching– Fix performance problems

Policy Injection Block

Uses magic Mostly elves Some wood nymphs for reliability

Just kidding.

Policy Injection Block Layer of abstraction Lets you hook functionality in at runtime

via config Intercepts calls in to an object’s

methods Think aspect-oriented programming or

dependency injection for methods

The Overall Design

Getting started with the PI block

Two ways to use Policy Injection:– Objects extend from MarshalByRef– Code against interfaces instead of concrete

classes Add references

– Microsoft.Practices.EnterpriseLibrary.PolicyInjection

– Microsoft.Practices.ObjectBuilder– Microsoft.Practices.EnterpriseLibrary.CallHandle

rs– Plus, whatever block you’ll reference from PI

Edit app.config/web.config with EntLibConfig.exe

Calling into the PI framework

Call PolicyInjection.Create<T>() or one of the overloads

Returns a wrapper to your object Call your methods through the wrapper

Configuration

EntLibConfig.exe Uses the

Remoting Policy Injector

Policy consists of– Matching Rules– Handlers

Matching Rules

Tells the framework when to run the policy

Handlers

Tells the framework what to do when it finds a policy match

Logging Handler

Through policy injection framework, intercepts calls

Writes message to log before and/or after

Logging Application Block

Logs activity in your app

Trace Listeners– Where does it

get stored? Formatters

– How does it get stored?

Filters– What to write?

Logging Block Design

Trace Listeners

Formatters

Demo

Add Policy Injection to an existing app Configure logging

Exception Handling Block

Allows you to define how to treat exceptions

Option: Catch and re-throw different exception

Option: Eat the exception

Design of the Exception Block

Demo

Add exception handling to our app via Policy Injection

Wrap Handlers Replace Handlers

Demo

Add Exception Handling to a WCF application

The Validation Block

About the Validation Block

Allows you to validate access to your objects

Validation logic can be stored outside of your objects in the configs

Validation can also be defined via attributes

Similar to a rules engine– Think Windows Workflow Rules “light”

Available Validators

And Composite Contains

Characters Date Time

Range Domain Enum

Conversion Not Null Object

Collection

Object Validator Or Composite Property

Compare Range Validator RegEx Relative Date

Time String Length Type Conversion

Common Validator Fields MessageTemplate

– Provides a human-readable error message– Overrides the default implementation

MessageTemplateResourceName– Enables messages in resource files

MessageTemplateResourceType Negate

– If statement evaluates to true rule fails– false succeeds

Tag– Category for the validation

Message Template Tokens

Think String.Format() Use these to create custom messages {0}

– Original value being validated {1}

– “Key” for the value– If property or field name (m_id or Id)– If object null

{2}– The tag value if available

Service Layer Pattern

From “Patterns Of Enterprise Application Architecture”by Martin Fowler, Randy Stafford, et al.Chapter 9

“Defines an application’s boundary with a layer of services that establishes a set of available operations and coordinates the application’s response in each operation.”

-Randy Stafford

Demo

Validate Restaurant with the ValidationFactory

The Caching Block

Allows you to cache return values from method, properties

Easy to add with the Policy Injection Block

Demo

Populate list of states using the caching block

Summary

Policy Injection Block Helps Speed Adoption

Logging Block Exception Handling Block Exception Handling in WCF Validation Block Caching Block

About the speaker

Owner, Benjamin Day Consulting, Inc.– Email: benday@benday.com– Web: http://www.benday.com– Blog: http://blog.benday.com

Trainer– Visual Studio Team System, Team Foundation

Server Microsoft MVP for C# Microsoft VSTS/TFS Customer Advisory

Council Leader of Beantown.NET INETA User

Group