Transcript Enterprise Library for .NET Framework 2.0: Core Architecture Enterprise Library for .NET Framework 2.0  Major new release of Enterprise Library  Designed for.

Enterprise Library for
.NET Framework 2.0:
Core Architecture
Enterprise Library for .NET Framework 2.0
 Major new release of Enterprise Library
 Designed for Microsoft® .NET Framework 2.0
• Leverages key new capabilities provided by the platform
• Certain features from Enterprise Library v1.x have been
deprecated in favor of the platform
 Scenarios and features largely unchanged
• Public application programming interfaces (APIs) not identical, but
changes are minor
• …but many improvements are hiding under the covers!
Key Changes from Enterprise Library 1.x
 Configuration now built on System.Configuration
• Configuration Application Block no longer exists
• Easier to use blocks with or without configuration files
 Instrumentation configurable and disabled by default
 Much improved Logging Application Block
• Flexibility and performance
 Simpler and more powerful Data Access Application Block
• Use with OLE-DB, Open Database Connectivity (ODBC) or any
managed provider
 Most of the Security Application Block has been removed
• Deprecated in favor of .NET Membership and Profile features
Enterprise Library for .NET Framework 2.0
Data
Access
Caching
Logging
Core
Plug-in
Cryptography
Config
Helpers
& Design
Instrumentation
Object
Builder
Exception
Handling
Security
Block Dependency
Optional Provider
Dependency
Enterprise Library for .NET Framework 2.0
Data
Access
Caching
Logging
Core
Plug-in
Cryptography
Config
Helpers
& Design
Instrumentation
Object
Builder
Exception
Handling
Security
Block Dependency
Optional Provider
Dependency
Core Architecture
 Configuration runtime
 Configuration design and tooling
 Instrumentation
 Factories and object builder
Configuration in Enterprise Library
 All Enterprise Library blocks are configurable
• Controls how the blocks work in your application
• Specifies which plug-ins you are using
 Previous versions of Enterprise Library included a
Configuration Application Block
• Supported reading/writing complex configuration objects from
pluggable storage
• Used by all Enterprise Library blocks, and can be used by
customer code
 In Enterprise Library for .NET Framework 2.0, the
requirements are the same but the solution is different
System.Configuration in .NET 2.0
 Much more powerful than the Microsoft® .NET Framework
1.x classes
• Supports reading and writing rich graphs of objects
• Automatic serialization and deserialization between configuration
classes and XML using ConfigurationSection and
ConfigurationElement
 Some Enterprise Library 1.x features are not directly
supported
• Storing configuration somewhere other than XML Files
• Monitoring external changes to configuration
Configuration Runtime
 Enterprise Library for .NET Framework 2.0 uses
System.Configuration, but provides additional helper
classes to provide more functionality
• All blocks provide ConfigurationSections which are stored in
app.config / web.config by default
• All System.Configuration features such as encryption and using
external files are supported
 Configuration Runtime helper classes are in the Common
assembly
• Used by all Enterprise Library application blocks
• Can be used by your apps, but you generally won’t need to
Configuration Sources
app.config
/ web.config
Application Blocks
or Custom Code
Default
ConfigurationSource
=…
IConfigurationSource
SystemConfiguration
Source
FileConfiguration
Source
SqlConfiguration
Source
System.Configuration
File Watcher
app.config
/ web.config
foo.config
File Watcher
Configuration Sources
 Abstract interface that supports loading/saving
configuration and monitoring for changes
 Two implementations included in the core
• SystemConfigurationSource defers to System.Configuration to
read from default configuration file (plus adds file watchers)
• FileConfigurationSource defers to System.Configuration but reads
from arbitrary files
 SqlConfigurationSource included as a sample
• Requires that sections derive from
SerializableConfigurationSection
Choosing a Configuration Source
 Several ways of choosing a configuration source when
using Enterprise Library
 If you access blocks using static façades or factories
(Examples: DatabaseFactory, Logger), you will always use
the application’s default ConfigurationSource:
• If you define a ConfigurationSources section in your default.config
file, you can specify which type of source should be used
• If you don’t have this section, SystemConfigurationSource is used
 If you use the instance factories
(Examples:DatabaseProviderFactory, LogWriterFactory)
you can specify a configuration source of your choosing
• Instantiated directly or using ConfigurationSourceFactory
Configuration Source Examples
<enterpriseLibrary.ConfigurationSource selectedSource="fileSource">
<sources>
<add name="fileSource"
type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.FileConfigurationSource,
Microsoft.Practices.EnterpriseLibrary.Common" filePath="test.config"/>
<add name="systemSource"
type="Microsoft.Practices.EnterpriseLibrary.Common.Configuration.SystemConfigurationSource,
Microsoft.Practices.EnterpriseLibrary.Common"/>
</sources>
</enterpriseLibrary.ConfigurationSource>
// Use default source specified in the app.config / web.config file
Database db1 = DatabaseFactory.CreateDatabase(“Sales”);
// Use the specified source – you don’t need an app.config / web.config file
FileConfigurationSource fileSource = new FileConfigurationSource(“tom.config”);
DatabaseProviderFactory factory = new DatabaseProviderFactory(fileSource);
Database db2 = factory.Create(“Sales”);
Change Notifications
 IConfigurationSource supports monitoring configuration
data for changes
• AddSectionHandler(string sectionName,
ConfigurationChangedEventHandler handler)
• RemoveSectionHandler(string sectionName,
ConfigurationChangedEventHandler handler)
 Any code can register for changes and respond
accordingly
 In Enterprise Library, only the Logging Application Block
currently registers to receive change notification events
Configuration Design and Tooling
 Configuration tool eliminates the need to edit the blocks’
XML configuration files
• Quickly add default configuration for a block
• Strongly-typed properties and providers
• Validate configuration before you save
 No major changes to configuration tool user experience
from previous versions of Enterprise Library
 Configuration design-time subsystem can be used in your
own applications and blocks to provide a similar
experience for your users
Configuration Design-Time
 Improved API
• Simple base configuration design manager
• Better node registration and command registration
• 3 to 4 simple classes to register your custom provider
• No more OnSited 
 One configuration design manager per section
 Dependent configuration design managers
 Easy to interop with any .NET configuration
Instrumentation
 All Enterprise Library blocks include instrumentation to
assist in development, testing and operations
• Event Log events
• Performance Counters
• Microsoft® Windows® Management Instrumentation (WMI) events
 All instrumentation is disabled by default, but each type
can be individually enabled using the configuration tool
 Instrumentation code contained in common assembly can
be reused in your apps
Enabling Instrumentation
 Run the installer classes to create the instrumentation
artifacts:
• Run installservices.bat (using an admin account), or
• Run installutil.exe over each Enterprise Library assembly (using an
admin account), or
• Create your own installers/MSI that do this
 Configure instrumentation for your app using the tool
Instrumentation Architecture
 Event-driven architecture
Event
Log
Application or Block
calls
Instrumentation
Provider
Class(es)
Event
Instrumentation
Listener
Class(es)
Wires up
ObjectBuilder
Perf
Counters
WMI
Instrumentation
Configuration
Settings
Instrumentation Attributes
 Instrumentation is wired up using attributes:
• [InstrumentationListener]
Defined on a type within the block or application
Specifies which listener will deal with instrumentation events
• [InstrumentationProvider]
Defined on an event within the block or application
Specifies the name of the event being fired
• [InstrumentationConsumer]
Defined on a method within the instrumentation listener
The method contains the instrumentation logic, and the name must match the one
used in an [InstrumentationProvider] declaration
Instrumentation Example
public class Database : IInstrumentationEventProvider {
DbConnection OpenConnection() {
// Do stuff
instrumentationProvider.FireConnectionOpenedEvent();
}
public object GetInstrumentationEventProvider() {
return instrumentationProvider;
}
}
[InstrumentationListener(
typeof(DataInstrumentationListener),
typeof(DataInstrumentationListenerBinder)
)]
public class
DataInstrumentationProvider {
[InstrumentationProvider("ConnectionOpene
d")]
public event EventHandler<EventArgs>
connectionOpened;
public void FireConnectionOpenedEvent()
{
connectionOpened(this, new
EventArgs());
}
internal class
DataInstrumentationListener :
InstrumentationListener {
public
DataInstrumentationListener(string
instanceName, bool perfCountersEnabled,
bool eventLogEnabled, bool wmiEnabled) :
base(perf…, event…, wmi…) {}
[InstrumentationConsumer(
“ConnectionOpened")]
public void ConnectionOpened(object
sender, EventArgs e) {
if (PerformanceCountersEnabled)
connectionOpenedCounter.Increment();
}
Instrumentation Installation Attributes
 Running installutil over an instrumented class should install all
required event log sources, WMI schemas and performance counters
 Enterprise Library provides a ReflectionInstaller which uses reflection
to find these, with the help of some attributes
 [HasInstallableResources]
• Indicates that there is instrumentation to install
 [PerformanceCountersDefinition]
• Defines the counters used by the block or app
 [EventLogDefinition]
• Defines the event log sources used by the block or app
Factories and Object Builder
 Objects inside application blocks need to be constructed
and configured
 There are different ways you can construct objects
depending on what you want to do
• Use a default configuration source
• Use a custom configuration source
• Don’t use any configuration at all
• Inject instrumentation
 Although each block is different, all rely on similar types of
factories for construction
Object Builder
 New subsystem shared between EntLib and Composite UI
Application Block
 Responsible for building objects inside the application
blocks
• Invoking the necessary custom factory using data from
configuration
• Configuring instrumentation for the blocks
 Can be leveraged from your own apps, but understanding
ObjectBuilder is not required to use Enterprise Library
Factories
Application Block
User
Code
Static Factory
or façade
Core
Configuration
Source
Instance
Provider Factory
Custom
Factory
Block Objects
Enterprise Library
Factory
Object Builder
Strategies
Using Static Facades and Factories
 Easiest way to use the blocks
 Configuration is retrieved from the default configuration
source
 Instrumentation is wired up (but may be disabled)
 Results in a call to an instance factory behind the scenes
 Examples:
• Dim db As Database = DatabaseFactory.CreateDatabase(“Sales”)
• Logger.Write(“My message”, “My Category”)
Using Instance Provider Factories
 You get slightly more control on how objects are created
 You can choose your own configuration source
 Instrumentation is wired up (but may be disabled)
 Examples:
• Dim factory As New DatabaseProviderFactory(configSource)
Dim db As Database = factory.Create(“Sales”)
• Dim factory As New LogWriterFactory(configSource)
Dim writer As LogWriter = factory.Create()
Creating Objects Directly
 New up the object and any dependent objects yourself
 Configuration sources are not used
 Object Builder is not involved
 Instrumentation will not be automatically wired up (but you
can add it yourself)
 Example:
• Dim db As SqlDatabase = New
SqlDatabase("server=(local)\SQLEXPRESS;database=EntLibQuic
kStarts;Integrated Security=true")
Resources
 Download Enterprise Library and related resources from:
• http://msdn.microsoft.com/practices
 Join the Enterprise Library Community at:
• http://practices.gotdotnet.com/projects/entlib
 Read blogs from the Enterprise Library team at:
• http://msdn.microsoft.com/practices/Comm/EntLibBlogs/