Home > Articles > Programming > Windows Programming

Configuration Data

  • Print
  • + Share This
This chapter is from the book

Access Mechanism (and Transient Storage)

You also need to think about how to access the configuration data. You can, of course, go to the persistent storage each and every time, but this is probably too costly if you need to go there often. Therefore, the following are a few techniques that I'd like to discuss for providing an access mechanism to transient storage. (Note that this list is not exhaustive.)

  • Using the Shared Properties Manager (SPM)
  • Using Object Construction (OC)
  • Using a Shared (static) member
  • Using the ThreadStatic attribute
  • Using Object Pooling (OP)

Once again, let's look at each of these techniques in detail, starting with the SPM.

Using the Shared Properties Manager (SPM)

The Shared Properties Manager (SPM) is an old, faithful component service that is still around. You can use it from your serviced components as a dictionary object to store keys and values, similar to the Application object in ASP.NET. However, the SPM can group the keys in property groups.

The programming model of the SPM is a bit different from other dictionary objects, but it's still quite simple. You can see a sample in Listing 2, where a value is read from the SPM (or written, if it wasn't found in the SPM).

Listing 2: Reading a Value That Is Stored in the SPM

Imports System.EnterpriseServices
Public Class SpmTest
  Inherits ServicedComponent

  Public Function Test() As String
    Dim theExist As Boolean
    Dim aManager As New SharedPropertyGroupManager()

    Dim aGroup As SharedPropertyGroup = _
    aManager.CreatePropertyGroup("MyGroup", _
    PropertyLockMode.SetGet, _
    PropertyReleaseMode.Process, theExist)

    Dim aProperty As SharedProperty = _
    aGroup.CreateProperty("MyProperty", theExist)

    If Not theExist Then
      aProperty.Value = Now.ToString()
    End If
    Return aProperty.Value.ToString()

  End Function
End Class

Using Object Construction (OC)

In the previous section, I talked about OC as a mechanism for persistent storage, but it is also a mechanism for accessing transient storage. Refer to Listing 1 for a code sample.

Using a Shared (Static) Member

Using a Shared member variable is by no means specific to serviced components, of course. It's a simple and efficient mechanism. Its main problem is that you have only one single instance that is shared by all users and their components, which can lead to concurrency conflicts when the value isn't read-only. Because of this, you have to protect the value by writing thread-safe code. This will result in wait states in a highly stressed environment when the Shared member is to be used all the time. Most often, it won't cause you any problems, but in some situations—as I said, under extreme load—it might be a show-stopper.

To get a cheaper locking solution, you can implement a ReaderWriter lock instead. That means that there might be several readers at the same time, but only one writer. Do you get a de[as]ja[ag] vu feeling from the database area? You can find more information about how to implement a ReaderWriter lock in the .NET online help.

NOTE

I must warn you against trying to write thread-safe code manually. If you do so, you might create a debugging nightmare for yourself, either now or in the future. Be careful and make sure you know what you're doing.

Using the ThreadStatic Attribute

It's possible to use TLS in .NET, too, so that each thread will have its own local data. It's easily achievable by just marking a Shared variable with the ThreadStatic attribute.

This will mean that you will have as many instances of the data as you have threads. There will be no blocking because each thread will have the data it needs. This might also mean a problem for you because you waste memory, but that is most often not the case for configuration data.

Using Object Pooling (OP)

The final technique that I'd like to discuss for providing an access mechanism to transient storage is using Object Pooling (OP) in serviced components. If you still remember the technique of thread-specific global variables from the days of VB6 (which I discussed earlier in this section about configuration data), OP is another technique that comes close to that solution. Not that pooled objects are tied to a specific thread, but you will have a pool of n number of objects with OP so that you can avoid the situation of several simultaneous requests of the same value leading to wait states. On the other hand, the larger the pool, the larger the amount of used memory, of course.

However, while it is an advantage that several instances minimize contention, it's a disadvantage if it's necessary for all instances to have the same values all the time. If it is necessary, you'd better use one single value instead (unless it's not a "fetch once, use many times" type of data).

NOTE

Both Object Construction and Object Pooling can be used even when the object is located in the context of the caller because neither of these services is built with interception.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020