abstract methods - Page 131

Why are we getting a WCF "Framing error" on some machines but not others

- by Ian Ringrose

We have just found we are getting “framing errors” (as reported by the WCF logs) when running our system on some customer test machine. It all works ok on our development machines. We have an abstract base class, with KnownType attributes for all its sub classes. One of it’s subclass is missing it’s DataContract attribute. However it all worked on our test machine! On the customers test machine, we got “framing error” showing up the WCF logs, this is not the error message I have seen in the past when missing a DataContract attribute, or a KnownType attribute. I wish to get to the bottom of this, as we can no longer have confidence in our ability to test the system before giving it to the customer until we can make our machines behave the some as the customer’s machines. Code that try to show what I am talking about, (not the real code) [DataContract()] [KnownType(typeof(SubClass1))] [KnownType(typeof(SubClass2))] // other subclasses with data members public abstract class Base { [DataMember] public int LotsMoreItemsThenThisInRealLife; } /// <summary> /// This works on some machines (not not others) when passed to Contract::DoIt, /// note the missing [DataContract()] /// </summary> public class SubClass1 : Base { // has no data members } /// <summary> /// This works in all cases when passed to Contract::DoIt /// </summary> [DataContract()] public class SubClass2 : Base { // has no data members } public interface IContract { void DoIt(Base[] items); } public static class MyProgram { public static IContract ConntectToServerOverWCF() { // lots of code ... return null; } public static void Startup() { IContract server = ConntectToServerOverWCF(); // this works all of the time server.DoIt(new Base[]{new SubClass2(){LotsMoreItemsThenThisInRealLife=2}}); // this works "in develperment" e.g. on our machines, but not on the customer's test machines! server.DoIt(new Base[] { new SubClass1() { LotsMoreItemsThenThisInRealLife = 2 } }); } }

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Generic Constraints And Type Parameters Mess

- by Dummy01

Hi everyone, I have the following base abstract class defined as: public abstract class BaseObject<T> : IComparable, IComparable<T>, IEquatable<T> {} I also have an interface defined as: public interface ICode<T> where T : struct { T Code { get; } } Now I want to derive a class that is inherited from BaseObject<T> and includes interface ICode<T>. I tried to define it like that: public class DerivedObject<T, U> : BaseObject<T>, ICode where T : DerivedObject<T, U> where U : struct { public DerivedObject(U code) { Code = code; } // From BaseObject protected override int InstanceCompareTo(T obj) { return Code.CompareTo(obj.Code); } // From BaseObject protected override bool InstanceEquals(T obj) { return Code.Equals(obj.Code); } // From ICode U _Code; public U Code { get { return _Code; } protected set { _Code = value; } } } The only error that comes from the compiler is for Code.CompareTo(obj.Code) with the message: 'U' does not contain a definition for 'CompareTo' and no extension method 'CompareTo' accepting a first argument of type 'U' could be found. But U is a value type and should know CompareTo. Have you any idea what I am doing wrong, or if I do all wrong? My final aim is to derive classes such these: public class Account : DerivedObject<Account, int> public class ItemGroup : DerivedObject<ItemGroup, string> Big Thanks In Advance!

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Cannot Find Symbol Method?

- by Aaron

In my driver program, This line gives me cannot find symbol error and I don't know why, the method is clearly defined in the SavingsAccount class, and I can refer to all other methods in my driver program but just not that one, I tried changing the type to double, and etc but still not working. Refer to ** Account acct2 = new SavingsAccount (name); acct2.calculateBalance(); SavingsAccount Class Inherited from Account Class: public class SavingsAccount extends Account { private final short minBalance = 0; private double overdraftFee; private double yearlyInterestRate = 0.02; private double interestAmount; public SavingsAccount (String name) { super(name); } public double withdraw (double amount) { if (accountBalance - amount >= minBalance) { accountBalance -= amount; System.out.print ("Withdraw Successful"); } else { accountBalance -= amount; overdraftFee = accountBalance * (0.10); accountBalance += overdraftFee; System.out.print ("Withdraw Succesful, however overdraft fee of 10% has been applied to your account"); } return accountBalance; } **public void calculateBalance () { interestAmount = (accountBalance * yearlyInterestRate); accountBalance += interestAmount; }** public String toString() { return super.toString() + " Interest Received: " + interestAmount; } } Account class, if needed import java.util.Random; import java.text.NumberFormat; public abstract class Account { protected double accountBalance; protected long accountNumber; protected String accountHolder; public Account (String name) { accountHolder = name; accountBalance = 0; Random accountNo = new Random(); accountNumber = accountNo.nextInt(100000); } public double deposit (double amount) { accountBalance += amount; return accountBalance; } public String toString() { NumberFormat accountBal = NumberFormat.getCurrencyInstance(); return "Account Balance: " + accountBal.format(accountBalance) + "\nAccount Number: " + accountNumber; } public String getAccountHolder() { return accountHolder; } public double getAccountBalance() { return accountBalance; } public abstract double withdraw (double amount); }

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Method not being resolved for dynamic generic type

- by kelloti

I have these types: public class GenericDao<T> { public T Save(T t) { return t; } } public abstract class DomainObject { // Some properties protected abstract dynamic Dao { get; } public virtual void Save() { var dao = Dao; dao.Save(this); } } public class Attachment : DomainObject { protected dynamic Dao { get { return new GenericDao<Attachment>(); } } } Then when I run this code it fails with RuntimeBinderException: Best overloaded method match for 'GenericDAO<Attachment.Save(Attachment)' has some invalid arguments var obj = new Attachment() { /* set properties */ }; obj.Save(); I've verified that in DomainObject.Save() "this" is definitely Attachment, so the error doesn't really make sense. Can anyone shed some light on why the method isn't resolving? Some more information - It succeeds if I change the contents of DomainObject.Save() to use reflection: public virtual void Save() { var dao = Dao; var type = dao.GetType(); var save = ((Type)type).GetMethod("Save"); save.Invoke(dao, new []{this}); }

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Is it advisable to have an interface as the return type?

- by wb

I have a set of classes with the same functions but with different logic. However, each class function can return a number of objects. It is safe to set the return type as the interface? Each class (all using the same interface) is doing this with different business logic. protected IMessage validateReturnType; <-- This is in an abstract class public bool IsValid() <-- This is in an abstract class { return (validateReturnType.GetType() == typeof(Success)); } public IMessage Validate() { if (name.Length < 5) { validateReturnType = new Error("Name must be 5 characters or greater."); } else { validateReturnType = new Success("Name is valid."); } return validateReturnType; } Are there any pitfalls with unit testing the return type of an function? Also, is it considered bad design to have functions needing to be run in order for them to succeed? In this example, Validate() would have to be run before IsValid() or else IsValid() would always return false. Thank you.

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Need some advice on MVC separation..

- by Zenph

I should note I am using Zend Framework. Although this shouldn't affect the concrete answer, it does mean there are several places I can implement my following method (action helper, controller etc). The issue is I have buildOptions() and parseOptions() method which takes $_GET/$_POST variables based on a 'tag' and builds rules which are then used in a select query. An example would be ?modelSort=id&modelOrder=asc The 'model' in the above obviously relates to the particular model, and it used as a 'tag' so that I can for example also have model2Sort and model2Order so there is no conflict between parameters. However, the trouble I am having now is where should these methods go? They are generally dealing with request params. I have been reading a lot about fat model, thin controller. Should this be in an abstract model. My thinking was that if it were, I would do something like: (note, I know I wouldn't call directly like this. Method would be used by child classes) $abstractModel-buildOptions($params); Where 'params' could be anything, like the request parameters $_GET or $_POST: $abstractModel-buildOptions($_GET); Now from what I can see the model is not inherintly dealing with request variables but rather parameters passed to the method. Advice? Where does this method belong? Model, Controller? Specifically on Zend, should it be an action helper, plugin, within an abstract model? Appreciate any advice.

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Class lookup structure array in C++

- by wyatt

I'm trying to create a structure array which links input strings to classes as follows: struct {string command; CommandPath cPath;} cPathLookup[] = { {"set an alarm", AlarmCommandPath}, {"send an email", EmailCommandPath}, {"", NULL} }; which will be used as follows: CommandPath *cPath = NULL; string input; getline(cin, input); for(int i = 0; cPathLookup[i] != ""; i++) { if(cPathLookup[i].command == input) cPath = new cPathLookup[i].cPath; } Obviously, this code is meaningless, but I think my intention is apparent - depending on input, I'd like cPath to be initialized as either a new AlarmCommandPath or a new EmailCommandPath. I could handle it with a function returning an instance depending on input, but a whole sequence of ifs just seems inelegant. I should also note that, in case it's not apparent and important, that AlarmCommandPath and EmailCommandPath are derived from CommandPath, and CommandPath is an abstract class. Thanks for any help you can offer. EDIT: I just noticed that, in spite of CommandPath being abstract, I have a declaration: CommandPath *cPath = NULL; in working code. Why does that compile?

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Fortran pointer as an argument to interface procedure

- by icarusthecow

Im trying to use interfaces to call different subroutines with different types, however, it doesnt seem to work when i use the pointer attribute. for example, take this sample code MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE INTERFACE ptr_interface MODULE PROCEDURE do_something END INTERFACE CONTAINS SUBROUTINE do_something(atype) CLASS(parent), POINTER :: atype ! code determines that this allocation is correct from input ALLOCATE(child::atype) WRITE (*,*) atype%q END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype CALL ptr_interface(ctype) END PROGRAM This gives error Error: There is no specific subroutine for the generic 'ptr_interface' at (1) however if i remove the pointer attribute in the subroutine it compiles fine. Now, normally this wouldnt be a problem, but for my use case i need to be able to treat that argument as a pointer, mainly so i can allocate it if necessary. Any suggestions? Mind you I'm new to fortran so I may have missed something edit: forgot to put the allocation in the parents subroutine, the initial input is unallocated EDIT 2 this is my second attempt, with caller side casting MODULE ptr_types TYPE, abstract :: parent INTEGER :: q END TYPE TYPE, extends(parent) :: child INTEGER :: m END TYPE TYPE, extends(parent) :: second INTEGER :: meow END TYPE CONTAINS SUBROUTINE do_something(this, type_num) CLASS(parent), POINTER :: this INTEGER type_num IF (type_num == 0) THEN ALLOCATE (child::this) ELSE IF (type_num == 1) THEN ALLOCATE (second::this) ENDIF END SUBROUTINE END MODULE PROGRAM testpass USE ptr_types CLASS(child), POINTER :: ctype SELECT TYPE(ctype) CLASS is (parent) CALL do_something(ctype, 0) END SELECT WRITE (*,*) ctype%q END PROGRAM however this still fails. in the select statement it complains that parent must extend child. Im sure this is due to restrictions when dealing with the pointer attribute, for type safety, however, im looking for a way to convert a pointer into its parent type for generic allocation. Rather than have to write separate allocation functions for every type and hope they dont collide in an interface or something. hopefully this example will illustrate a little more clearly what im trying to achieve, if you know a better way let me know

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eliminating duplicate Enum code

- by Don

Hi, I have a large number of Enums that implement this interface: /** * Interface for an enumeration, each element of which can be uniquely identified by it's code */ public interface CodableEnum { /** * Get the element with a particular code * @param code * @return */ public CodableEnum getByCode(String code); /** * Get the code that identifies an element of the enum * @return */ public String getCode(); } A typical example is: public enum IMType implements CodableEnum { MSN_MESSENGER("msn_messenger"), GOOGLE_TALK("google_talk"), SKYPE("skype"), YAHOO_MESSENGER("yahoo_messenger"); private final String code; IMType (String code) { this.code = code; } public String getCode() { return code; } public IMType getByCode(String code) { for (IMType e : IMType.values()) { if (e.getCode().equalsIgnoreCase(code)) { return e; } } } } As you can imagine these methods are virtually identical in all implementations of CodableEnum. I would like to eliminate this duplication, but frankly don't know how. I tried using a class such as the following: public abstract class DefaultCodableEnum implements CodableEnum { private final String code; DefaultCodableEnum(String code) { this.code = code; } public String getCode() { return this.code; } public abstract CodableEnum getByCode(String code); } But this turns out to be fairly useless because: An enum cannot extend a class Elements of an enum (SKYPE, GOOGLE_TALK, etc.) cannot extend a class I cannot provide a default implementation of getByCode(), because DefaultCodableEnum is not itself an Enum. I tried changing DefaultCodableEnum to extend java.lang.Enum, but this doesn't appear to be allowed. Any suggestions that do not rely on reflection? Thanks, Don

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Is there a way to deserialize an object into "$this"?

- by Andreas Bonini

I'm writing a class to handle a memcached object. The idea was to create abstract class Cachable and all the cachable objects (such as User, Post, etc) would be subclasses of said class. The class offers some method such as Load() which calls the abstract function LoadFromDB() if the object is not cached, functions to refresh/invalidate the cache, etc. The main problem is in Load(); I wanted to do something similar: protected function Load($id) { $this->memcacheId = $id; $this->Connect(); $cached = $this->memcache->get(get_class($this) . ':' . $id); if($cached === false) { $this->SetLoaded(LoadFromDB($id)); UpdateCache(); } else { $this = $cached; $this->SetLoaded(true); } } Unfortunately I need $this to become $cached (the cached object); is there any way to do that? Was the "every cachable object derives from the cachable class" a bad design idea?

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Why can't I pass an object of type T to a method on an object of type <? extends T>?

- by Matt

In Java, assume I have the following class Container that contains a list of class Items: public class Container<T> { private List<Item<? extends T>> items; private T value; public Container(T value) { this.value = value; } public void addItem(Item item) { items.add(item); } public void doActions() { for (Item item : items) { item.doAction(value); } } } public abstract class Item<T> { public abstract void doAction(T item); } Eclipse gives the error: The method doAction(capture#1-of ? extends T) in the type Item is not applicable for the arguments (T) I've been reading generics examples and various postings around, but I still can't figure out why this isn't allowed. Eclipse also doesn't give any helpful tips in its proposed fix, either. The variable value is of type T, why wouldn't it be applicable for ? extends T?.

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C# Function Inheritance--Use Child Class Vars with Base Class Function

- by Sean O'Connor

Good day, I have a fairly simple question to experienced C# programmers. Basically, I would like to have an abstract base class that contains a function that relies on the values of child classes. I have tried code similar to the following, but the compiler complains that SomeVariable is null when SomeFunction() attempts to use it. Base class: public abstract class BaseClass { protected virtual SomeType SomeVariable; public BaseClass() { this.SomeFunction(); } protected void SomeFunction() { //DO SOMETHING WITH SomeVariable } } A child class: public class ChildClass:BaseClass { protected override SomeType SomeVariable=SomeValue; } Now I would expect that when I do: ChildClass CC=new ChildClass(); A new instance of ChildClass should be made and CC would run its inherited SomeFunction using SomeValue. However, this is not what happens. The compiler complains that SomeVariable is null in BaseClass. Is what I want to do even possible in C#? I have used other managed languages that allow me to do such things, so I certain I am just making a simple mistake here. Any help is greatly appreciated, thank you.

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Unit Tests Architecture Question

- by Tom Tresansky

So I've started to layout unit tests for the following bit of code: public interface MyInterface { void MyInterfaceMethod1(); void MyInterfaceMethod2(); } public class MyImplementation1 implements MyInterface { void MyInterfaceMethod1() { // do something } void MyInterfaceMethod2() { // do something else } void SubRoutineP() { // other functionality specific to this implementation } } public class MyImplementation2 implements MyInterface { void MyInterfaceMethod1() { // do a 3rd thing } void MyInterfaceMethod2() { // do something completely different } void SubRoutineQ() { // other functionality specific to this implementation } } with several implementations and the expectation of more to come. My initial thought was to save myself time re-writing unit tests with something like this: public abstract class MyInterfaceTester { protected MyInterface m_object; @Setup public void setUp() { m_object = getTestedImplementation(); } public abstract MyInterface getTestedImplementation(); @Test public void testMyInterfaceMethod1() { // use m_object to run tests } @Test public void testMyInterfaceMethod2() { // use m_object to run tests } } which I could then subclass easily to test the implementation specific additional methods like so: public class MyImplementation1Tester extends MyInterfaceTester { public MyInterface getTestedImplementation() { return new MyImplementation1(); } @Test public void testSubRoutineP() { // use m_object to run tests } } and likewise for implmentation 2 onwards. So my question really is: is there any reason not to do this? JUnit seems to like it just fine, and it serves my needs, but I haven't really seen anything like it in any of the unit testing books and examples I've been reading. Is there some best practice I'm unwittingly violating? Am I setting myself up for heartache down the road? Is there simply a much better way out there I haven't considered? Thanks for any help.

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Hibernate many-to-many relationship

- by Capitan

I have two mapped types, related many-to-many. @Entity @Table(name = "students") public class Student{ ... @ManyToMany(fetch = FetchType.EAGER) @JoinTable( name = "students2courses", joinColumns = { @JoinColumn( name = "student_id", referencedColumnName = "_id") }, inverseJoinColumns = { @JoinColumn( name = "course_id", referencedColumnName = "_id") }) public Set<Course> getCourses() { return courses; } public void setCourses(Set<Course> courses) { this.courses = courses; } ... } __ @Entity @Table(name = "courses") public class Course{ ... @ManyToMany(fetch = FetchType.EAGER, mappedBy = "courses") public Set<Student> getStudents() { return students; } public void setStudents(Set<Student> students) { this.students = students; } ... } But if I update/delete Course entity, records are not created/deleted in table students2courses. (with Student entity updating/deleting goes as expected) I wrote abstract class HibObject public abstract class HibObject { public String getRemoveMTMQuery() { return null; } } which is inherited by Student and Course. In DAO I added this code (for delete() method): String query = obj.getRemoveMTMQuery(); if (query != null) { session.createSQLQuery(query).executeUpdate(); } and I ovrerided method getRemoveMTMQuery() for Course @Override @Transient public String getRemoveMTMQuery() { return "delete from students2courses where course_id = " + id + ";"; } Now it works but I think it's a bad code. Is there a best way to solve this problem?

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Main purpose of this task is to calculate volumes and surface areas of three dimensional geometric shapes like, cylinders, cones.

- by Csc_Girl_Geek

In Java Language Design your classes as below introducing: an Interface named “GeometricShapes” an abstract class named “ThreeDShapes” two child classes of ThreeDShapes: Cylinders and Cones. One test class names “TestShapes” Get the output for volumes and surface areas of cylinders and cones along with respective values of their appropriate input variables. Try to use toString() method and array. Your classes should be designed with methods that are required for Object-Oriented programming. So Far I Have: package Assignment2; public interface GeometricShapes { public void render(); public int[] getPosition(); public void setPosition(int x, int y); } package Assignment2; public abstract class ThreeDShapes implements GeometricShapes { public int[] position; public int[] size; public ThreeDShapes() { } public int[] getPosition() { return position; } public void setPosition(int x, int y) { position[0] = x; position[1] = y; } } package Assignment2; public class Cylinders extends ThreeDShapes { public Cylinder() { } public void render() { } } I don't think this is right and I do not know how to fix it. :( Please help.

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What does this Java generics paradigm do and what is it called?

- by Tom

I'm looking at some Java classes that have the following form: public abstract class A <E extends A<E>> implements Comparable <E> { public final int compareTo( E other ) { // etc } } public class B extends A { // etc } public class C extends A <C> { // etc } My usage of "Comparable" here is just to illustrate a possible use of the generic parameter "E". Does this usage of generics/inheritance have a name? What is it used for? My impression is that this allows the abstract class to provide a common implementation of a method (such as compareTo) without having to provide it in the subclasses. However, in this example, unlike an inherited method it would restrict subclasses to invoking compareTo on other instances of the same subclass, rather than any "A" subclass. Does this sound right? Anyway, just curious if any gurus out there have seen this before and know what it does. Thanks!

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jQuery Globalization Plugin from Microsoft

- by ScottGu

Last month I blogged about how Microsoft is starting to make code contributions to jQuery, and about some of the first code contributions we were working on: jQuery Templates and Data Linking support. Today, we released a prototype of a new jQuery Globalization Plugin that enables you to add globalization support to your JavaScript applications. This plugin includes globalization information for over 350 cultures ranging from Scottish Gaelic, Frisian, Hungarian, Japanese, to Canadian English. We will be releasing this plugin to the community as open-source. You can download our prototype for the jQuery Globalization plugin from our Github repository: http://github.com/nje/jquery-glob You can also download a set of samples that demonstrate some simple use-cases with it here. Understanding Globalization The jQuery Globalization plugin enables you to easily parse and format numbers, currencies, and dates for different cultures in JavaScript. For example, you can use the Globalization plugin to display the proper currency symbol for a culture: You also can use the Globalization plugin to format dates so that the day and month appear in the right order and the day and month names are correctly translated: Notice above how the Arabic year is displayed as 1431. This is because the year has been converted to use the Arabic calendar. Some cultural differences, such as different currency or different month names, are obvious. Other cultural differences are surprising and subtle. For example, in some cultures, the grouping of numbers is done unevenly. In the "te-IN" culture (Telugu in India), groups have 3 digits and then 2 digits. The number 1000000 (one million) is written as "10,00,000". Some cultures do not group numbers at all. All of these subtle cultural differences are handled by the jQuery Globalization plugin automatically. Getting dates right can be especially tricky. Different cultures have different calendars such as the Gregorian and UmAlQura calendars. A single culture can even have multiple calendars. For example, the Japanese culture uses both the Gregorian calendar and a Japanese calendar that has eras named after Japanese emperors. The Globalization Plugin includes methods for converting dates between all of these different calendars. Using Language Tags The jQuery Globalization plugin uses the language tags defined in the RFC 4646 and RFC 5646 standards to identity cultures (see http://tools.ietf.org/html/rfc5646). A language tag is composed out of one or more subtags separated by hyphens. For example: Language Tag Language Name (in English) en-AU English (Australia) en-BZ English (Belize) en-CA English (Canada) Id Indonesian zh-CHS Chinese (Simplified) Legacy Zu isiZulu Notice that a single language, such as English, can have several language tags. Speakers of English in Canada format numbers, currencies, and dates using different conventions than speakers of English in Australia or the United States. You can find the language tag for a particular culture by using the Language Subtag Lookup tool located here: http://rishida.net/utils/subtags/ The jQuery Globalization plugin download includes a folder named globinfo that contains the information for each of the 350 cultures. Actually, this folder contains more than 700 files because the folder includes both minified and un-minified versions of each file. For example, the globinfo folder includes JavaScript files named jQuery.glob.en-AU.js for English Australia, jQuery.glob.id.js for Indonesia, and jQuery.glob.zh-CHS for Chinese (Simplified) Legacy. Example: Setting a Particular Culture Imagine that you have been asked to create a German website and want to format all of the dates, currencies, and numbers using German formatting conventions correctly in JavaScript on the client. The HTML for the page might look like this: Notice the span tags above. They mark the areas of the page that we want to format with the Globalization plugin. We want to format the product price, the date the product is available, and the units of the product in stock. To use the jQuery Globalization plugin, we’ll add three JavaScript files to the page: the jQuery library, the jQuery Globalization plugin, and the culture information for a particular language: In this case, I’ve statically added the jQuery.glob.de-DE.js JavaScript file that contains the culture information for German. The language tag “de-DE” is used for German as spoken in Germany. Now that I have all of the necessary scripts, I can use the Globalization plugin to format the product price, date available, and units in stock values using the following client-side JavaScript: The jQuery Globalization plugin extends the jQuery library with new methods - including new methods named preferCulture() and format(). The preferCulture() method enables you to set the default culture used by the jQuery Globalization plugin methods. Notice that the preferCulture() method accepts a language tag. The method will find the closest culture that matches the language tag. The $.format() method is used to actually format the currencies, dates, and numbers. The second parameter passed to the $.format() method is a format specifier. For example, passing “c” causes the value to be formatted as a currency. The ReadMe file at github details the meaning of all of the various format specifiers: http://github.com/nje/jquery-glob When we open the page in a browser, everything is formatted correctly according to German language conventions. A euro symbol is used for the currency symbol. The date is formatted using German day and month names. Finally, a period instead of a comma is used a number separator: You can see a running example of the above approach with the 3_GermanSite.htm file in this samples download. Example: Enabling a User to Dynamically Select a Culture In the previous example we explicitly said that we wanted to globalize in German (by referencing the jQuery.glob.de-DE.js file). Let’s now look at the first of a few examples that demonstrate how to dynamically set the globalization culture to use. Imagine that you want to display a dropdown list of all of the 350 cultures in a page. When someone selects a culture from the dropdown list, you want all of the dates in the page to be formatted using the selected culture. Here’s the HTML for the page: Notice that all of the dates are contained in a tag with a data-date attribute (data-* attributes are a new feature of HTML 5 that conveniently also still work with older browsers). We’ll format the date represented by the data-date attribute when a user selects a culture from the dropdown list. In order to display dates for any possible culture, we’ll include the jQuery.glob.all.js file like this: The jQuery Globalization plugin includes a JavaScript file named jQuery.glob.all.js. This file contains globalization information for all of the more than 350 cultures supported by the Globalization plugin. At 367KB minified, this file is not small. Because of the size of this file, unless you really need to use all of these cultures at the same time, we recommend that you add the individual JavaScript files for particular cultures that you intend to support instead of the combined jQuery.glob.all.js to a page. In the next sample I’ll show how to dynamically load just the language files you need. Next, we’ll populate the dropdown list with all of the available cultures. We can use the $.cultures property to get all of the loaded cultures: Finally, we’ll write jQuery code that grabs every span element with a data-date attribute and format the date: The jQuery Globalization plugin’s parseDate() method is used to convert a string representation of a date into a JavaScript date. The plugin’s format() method is used to format the date. The “D” format specifier causes the date to be formatted using the long date format. And now the content will be globalized correctly regardless of which of the 350 languages a user visiting the page selects. You can see a running example of the above approach with the 4_SelectCulture.htm file in this samples download. Example: Loading Globalization Files Dynamically As mentioned in the previous section, you should avoid adding the jQuery.glob.all.js file to a page whenever possible because the file is so large. A better alternative is to load the globalization information that you need dynamically. For example, imagine that you have created a dropdown list that displays a list of languages: The following jQuery code executes whenever a user selects a new language from the dropdown list. The code checks whether the globalization file associated with the selected language has already been loaded. If the globalization file has not been loaded then the globalization file is loaded dynamically by taking advantage of the jQuery $.getScript() method. The globalizePage() method is called after the requested globalization file has been loaded, and contains the client-side code to perform the globalization. The advantage of this approach is that it enables you to avoid loading the entire jQuery.glob.all.js file. Instead you only need to load the files that you need and you don’t need to load the files more than once. The 5_Dynamic.htm file in this samples download demonstrates how to implement this approach. Example: Setting the User Preferred Language Automatically Many websites detect a user’s preferred language from their browser settings and automatically use it when globalizing content. A user can set a preferred language for their browser. Then, whenever the user requests a page, this language preference is included in the request in the Accept-Language header. When using Microsoft Internet Explorer, you can set your preferred language by following these steps: Select the menu option Tools, Internet Options. Select the General tab. Click the Languages button in the Appearance section. Click the Add button to add a new language to the list of languages. Move your preferred language to the top of the list. Notice that you can list multiple languages in the Language Preference dialog. All of these languages are sent in the order that you listed them in the Accept-Language header: Accept-Language: fr-FR,id-ID;q=0.7,en-US;q=0.3 Strangely, you cannot retrieve the value of the Accept-Language header from client JavaScript. Microsoft Internet Explorer and Mozilla Firefox support a bevy of language related properties exposed by the window.navigator object, such as windows.navigator.browserLanguage and window.navigator.language, but these properties represent either the language set for the operating system or the language edition of the browser. These properties don’t enable you to retrieve the language that the user set as his or her preferred language. The only reliable way to get a user’s preferred language (the value of the Accept-Language header) is to write server code. For example, the following ASP.NET page takes advantage of the server Request.UserLanguages property to assign the user’s preferred language to a client JavaScript variable named acceptLanguage (which then allows you to access the value using client-side JavaScript): In order for this code to work, the culture information associated with the value of acceptLanguage must be included in the page. For example, if someone’s preferred culture is fr-FR (French in France) then you need to include either the jQuery.glob.fr-FR.js or the jQuery.glob.all.js JavaScript file in the page or the culture information won’t be available. The “6_AcceptLanguages.aspx” sample in this samples download demonstrates how to implement this approach. If the culture information for the user’s preferred language is not included in the page then the $.preferCulture() method will fall back to using the neutral culture (for example, using jQuery.glob.fr.js instead of jQuery.glob.fr-FR.js). If the neutral culture information is not available then the $.preferCulture() method falls back to the default culture (English). Example: Using the Globalization Plugin with the jQuery UI DatePicker One of the goals of the Globalization plugin is to make it easier to build jQuery widgets that can be used with different cultures. We wanted to make sure that the jQuery Globalization plugin could work with existing jQuery UI plugins such as the DatePicker plugin. To that end, we created a patched version of the DatePicker plugin that can take advantage of the Globalization plugin when rendering a calendar. For example, the following figure illustrates what happens when you add the jQuery Globalization and the patched jQuery UI DatePicker plugin to a page and select Indonesian as the preferred culture: Notice that the headers for the days of the week are displayed using Indonesian day name abbreviations. Furthermore, the month names are displayed in Indonesian. You can download the patched version of the jQuery UI DatePicker from our github website. Or you can use the version included in this samples download and used by the 7_DatePicker.htm sample file. Summary I’m excited about our continuing participation in the jQuery community. This Globalization plugin is the third jQuery plugin that we’ve released. We’ve really appreciated all of the great feedback and design suggestions on the jQuery templating and data-linking prototypes that we released earlier this year. We also want to thank the jQuery and jQuery UI teams for working with us to create these plugins. Hope this helps, Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. You can follow me at: twitter.com/scottgu

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Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

- by mortezam

A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail { public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } public class BankAccount : BillingDetail { public string BankName { get; set; } public string Swift { get; set; } } public class CreditCard : BillingDetail { public int CardType { get; set; } public string ExpiryMonth { get; set; } public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext { public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount) FROM BillingDetails AS b WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT [Extent1].[Discriminator] AS [Discriminator], [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift], [Extent1].[CardType] AS [CardType], [Extent1].[ExpiryMonth] AS [ExpiryMonth], [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) { modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA")) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1)) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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Is there a Telecommunications Reference Architecture?

- by raul.goycoolea

@font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Abstract Reference architecture provides needed architectural information that can be provided in advance to an enterprise to enable consistent architectural best practices. Enterprise Reference Architecture helps business owners to actualize their strategies, vision, objectives, and principles. It evaluates the IT systems, based on Reference Architecture goals, principles, and standards. It helps to reduce IT costs by increasing functionality, availability, scalability, etc. Telecom Reference Architecture provides customers with the flexibility to view bundled service bills online with the provision of multiple services. It provides real-time, flexible billing and charging systems, to handle complex promotions, discounts, and settlements with multiple parties. This paper attempts to describe the Reference Architecture for the Telecom Enterprises. It lays the foundation for a Telecom Reference Architecture by articulating the requirements, drivers, and pitfalls for telecom service providers. It describes generic reference architecture for telecom enterprises and moves on to explain how to achieve Enterprise Reference Architecture by using SOA. Introduction A Reference Architecture provides a methodology, set of practices, template, and standards based on a set of successful solutions implemented earlier. These solutions have been generalized and structured for the depiction of both a logical and a physical architecture, based on the harvesting of a set of patterns that describe observations in a number of successful implementations. It helps as a reference for the various architectures that an enterprise can implement to solve various problems. It can be used as the starting point or the point of comparisons for various departments/business entities of a company, or for the various companies for an enterprise. It provides multiple views for multiple stakeholders. Major artifacts of the Enterprise Reference Architecture are methodologies, standards, metadata, documents, design patterns, etc. Purpose of Reference Architecture In most cases, architects spend a lot of time researching, investigating, defining, and re-arguing architectural decisions. It is like reinventing the wheel as their peers in other organizations or even the same organization have already spent a lot of time and effort defining their own architectural practices. This prevents an organization from learning from its own experiences and applying that knowledge for increased effectiveness. Reference architecture provides missing architectural information that can be provided in advance to project team members to enable consistent architectural best practices. Enterprise Reference Architecture helps an enterprise to achieve the following at the abstract level: · Reference architecture is more of a communication channel to an enterprise · Helps the business owners to accommodate to their strategies, vision, objectives, and principles. · Evaluates the IT systems based on Reference Architecture Principles · Reduces IT spending through increasing functionality, availability, scalability, etc · A Real-time Integration Model helps to reduce the latency of the data updates Is used to define a single source of Information · Provides a clear view on how to manage information and security · Defines the policy around the data ownership, product boundaries, etc. · Helps with cost optimization across project and solution portfolios by eliminating unused or duplicate investments and assets · Has a shorter implementation time and cost Once the reference architecture is in place, the set of architectural principles, standards, reference models, and best practices ensure that the aligned investments have the greatest possible likelihood of success in both the near term and the long term (TCO). Common pitfalls for Telecom Service Providers Telecom Reference Architecture serves as the first step towards maturity for a telecom service provider. During the course of our assignments/experiences with telecom players, we have come across the following observations – Some of these indicate a lack of maturity of the telecom service provider: · In markets that are growing and not so mature, it has been observed that telcos have a significant amount of in-house or home-grown applications. In some of these markets, the growth has been so rapid that IT has been unable to cope with business demands. Telcos have shown a tendency to come up with workarounds in their IT applications so as to meet business needs. · Even for core functions like provisioning or mediation, some telcos have tried to manage with home-grown applications. · Most of the applications do not have the required scalability or maintainability to sustain growth in volumes or functionality. · Applications face interoperability issues with other applications in the operator's landscape. Integrating a new application or network element requires considerable effort on the part of the other applications. · Application boundaries are not clear, and functionality that is not in the initial scope of that application gets pushed onto it. This results in the development of the multiple, small applications without proper boundaries. · Usage of Legacy OSS/BSS systems, poor Integration across Multiple COTS Products and Internal Systems. Most of the Integrations are developed on ad-hoc basis and Point-to-Point Integration. · Redundancy of the business functions in different applications • Fragmented data across the different applications and no integrated view of the strategic data • Lot of performance Issues due to the usage of the complex integration across OSS and BSS systems However, this is where the maturity of the telecom industry as a whole can be of help. The collaborative efforts of telcos to overcome some of these problems have resulted in bodies like the TM Forum. They have come up with frameworks for business processes, data, applications, and technology for telecom service providers. These could be a good starting point for telcos to clean up their enterprise landscape. Industry Trends in Telecom Reference Architecture Telecom reference architectures are evolving rapidly because telcos are facing business and IT challenges. “The reality is that there probably is no killer application, no silver bullet that the telcos can latch onto to carry them into a 21st Century.... Instead, there are probably hundreds – perhaps thousands – of niche applications.... And the only way to find which of these works for you is to try out lots of them, ramp up the ones that work, and discontinue the ones that fail.” – Martin Creaner President & CTO TM Forum. The following trends have been observed in telecom reference architecture: · Transformation of business structures to align with customer requirements · Adoption of more Internet-like technical architectures. The Web 2.0 concept is increasingly being used. · Virtualization of the traditional operations support system (OSS) · Adoption of SOA to support development of IP-based services · Adoption of frameworks like Service Delivery Platforms (SDPs) and IP Multimedia Subsystem · (IMS) to enable seamless deployment of various services over fixed and mobile networks · Replacement of in-house, customized, and stove-piped OSS/BSS with standards-based COTS products · Compliance with industry standards and frameworks like eTOM, SID, and TAM to enable seamless integration with other standards-based products Drivers of Reference Architecture The drivers of the Reference Architecture are Reference Architecture Goals, Principles, and Enterprise Vision and Telecom Transformation. The details are depicted below diagram. @font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }div.Section1 { page: Section1; } Figure 1. Drivers for Reference Architecture @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Today’s telecom reference architectures should seamlessly integrate traditional legacy-based applications and transition to next-generation network technologies (e.g., IP multimedia subsystems). This has resulted in new requirements for flexible, real-time billing and OSS/BSS systems and implications on the service provider’s organizational requirements and structure. Telecom reference architectures are today expected to: · Integrate voice, messaging, email and other VAS over fixed and mobile networks, back end systems · Be able to provision multiple services and service bundles • Deliver converged voice, video and data services · Leverage the existing Network Infrastructure · Provide real-time, flexible billing and charging systems to handle complex promotions, discounts, and settlements with multiple parties. · Support charging of advanced data services such as VoIP, On-Demand, Services (e.g. Video), IMS/SIP Services, Mobile Money, Content Services and IPTV. · Help in faster deployment of new services • Serve as an effective platform for collaboration between network IT and business organizations · Harness the potential of converging technology, networks, devices and content to develop multimedia services and solutions of ever-increasing sophistication on a single Internet Protocol (IP) · Ensure better service delivery and zero revenue leakage through real-time balance and credit management · Lower operating costs to drive profitability Enterprise Reference Architecture The Enterprise Reference Architecture (RA) fills the gap between the concepts and vocabulary defined by the reference model and the implementation. Reference architecture provides detailed architectural information in a common format such that solutions can be repeatedly designed and deployed in a consistent, high-quality, supportable fashion. This paper attempts to describe the Reference Architecture for the Telecom Application Usage and how to achieve the Enterprise Level Reference Architecture using SOA. • Telecom Reference Architecture • Enterprise SOA based Reference Architecture Telecom Reference Architecture Tele Management Forum’s New Generation Operations Systems and Software (NGOSS) is an architectural framework for organizing, integrating, and implementing telecom systems. NGOSS is a component-based framework consisting of the following elements: · The enhanced Telecom Operations Map (eTOM) is a business process framework. · The Shared Information Data (SID) model provides a comprehensive information framework that may be specialized for the needs of a particular organization. · The Telecom Application Map (TAM) is an application framework to depict the functional footprint of applications, relative to the horizontal processes within eTOM. · The Technology Neutral Architecture (TNA) is an integrated framework. TNA is an architecture that is sustainable through technology changes. NGOSS Architecture Standards are: · Centralized data · Loosely coupled distributed systems · Application components/re-use · A technology-neutral system framework with technology specific implementations · Interoperability to service provider data/processes · Allows more re-use of business components across multiple business scenarios · Workflow automation The traditional operator systems architecture consists of four layers, · Business Support System (BSS) layer, with focus toward customers and business partners. Manages order, subscriber, pricing, rating, and billing information. · Operations Support System (OSS) layer, built around product, service, and resource inventories. · Networks layer – consists of Network elements and 3rd Party Systems. · Integration Layer – to maximize application communication and overall solution flexibility. Reference architecture for telecom enterprises is depicted below. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 2. Telecom Reference Architecture The major building blocks of any Telecom Service Provider architecture are as follows: 1. Customer Relationship Management CRM encompasses the end-to-end lifecycle of the customer: customer initiation/acquisition, sales, ordering, and service activation, customer care and support, proactive campaigns, cross sell/up sell, and retention/loyalty. CRM also includes the collection of customer information and its application to personalize, customize, and integrate delivery of service to a customer, as well as to identify opportunities for increasing the value of the customer to the enterprise. The key functionalities related to Customer Relationship Management are · Manage the end-to-end lifecycle of a customer request for products. · Create and manage customer profiles. · Manage all interactions with customers – inquiries, requests, and responses. · Provide updates to Billing and other south bound systems on customer/account related updates such as customer/ account creation, deletion, modification, request bills, final bill, duplicate bills, credit limits through Middleware. · Work with Order Management System, Product, and Service Management components within CRM. · Manage customer preferences – Involve all the touch points and channels to the customer, including contact center, retail stores, dealers, self service, and field service, as well as via any media (phone, face to face, web, mobile device, chat, email, SMS, mail, the customer's bill, etc.). · Support single interface for customer contact details, preferences, account details, offers, customer premise equipment, bill details, bill cycle details, and customer interactions. CRM applications interact with customers through customer touch points like portals, point-of-sale terminals, interactive voice response systems, etc. The requests by customers are sent via fulfillment/provisioning to billing system for ordering processing. 2. Billing and Revenue Management Billing and Revenue Management handles the collection of appropriate usage records and production of timely and accurate bills – for providing pre-bill usage information and billing to customers; for processing their payments; and for performing payment collections. In addition, it handles customer inquiries about bills, provides billing inquiry status, and is responsible for resolving billing problems to the customer's satisfaction in a timely manner. This process grouping also supports prepayment for services. The key functionalities provided by these applications are · To ensure that enterprise revenue is billed and invoices delivered appropriately to customers. · To manage customers’ billing accounts, process their payments, perform payment collections, and monitor the status of the account balance. · To ensure the timely and effective fulfillment of all customer bill inquiries and complaints. · Collect the usage records from mediation and ensure appropriate rating and discounting of all usage and pricing. · Support revenue sharing; split charging where usage is guided to an account different from the service consumer. · Support prepaid and post-paid rating. · Send notification on approach / exceeding the usage thresholds as enforced by the subscribed offer, and / or as setup by the customer. · Support prepaid, post paid, and hybrid (where some services are prepaid and the rest of the services post paid) customers and conversion from post paid to prepaid, and vice versa. · Support different billing function requirements like charge prorating, promotion, discount, adjustment, waiver, write-off, account receivable, GL Interface, late payment fee, credit control, dunning, account or service suspension, re-activation, expiry, termination, contract violation penalty, etc. · Initiate direct debit to collect payment against an invoice outstanding. · Send notification to Middleware on different events; for example, payment receipt, pre-suspension, threshold exceed, etc. Billing systems typically get usage data from mediation systems for rating and billing. They get provisioning requests from order management systems and inquiries from CRM systems. Convergent and real-time billing systems can directly get usage details from network elements. 3. Mediation Mediation systems transform/translate the Raw or Native Usage Data Records into a general format that is acceptable to billing for their rating purposes. The following lists the high-level roles and responsibilities executed by the Mediation system in the end-to-end solution. · Collect Usage Data Records from different data sources – like network elements, routers, servers – via different protocol and interfaces. · Process Usage Data Records – Mediation will process Usage Data Records as per the source format. · Validate Usage Data Records from each source. · Segregates Usage Data Records coming from each source to multiple, based on the segregation requirement of end Application. · Aggregates Usage Data Records based on the aggregation rule if any from different sources. · Consolidates multiple Usage Data Records from each source. · Delivers formatted Usage Data Records to different end application like Billing, Interconnect, Fraud Management, etc. · Generates audit trail for incoming Usage Data Records and keeps track of all the Usage Data Records at various stages of mediation process. · Checks duplicate Usage Data Records across files for a given time window. 4. Fulfillment This area is responsible for providing customers with their requested products in a timely and correct manner. It translates the customer's business or personal need into a solution that can be delivered using the specific products in the enterprise's portfolio. This process informs the customers of the status of their purchase order, and ensures completion on time, as well as ensuring a delighted customer. These processes are responsible for accepting and issuing orders. They deal with pre-order feasibility determination, credit authorization, order issuance, order status and tracking, customer update on customer order activities, and customer notification on order completion. Order management and provisioning applications fall into this category. The key functionalities provided by these applications are · Issuing new customer orders, modifying open customer orders, or canceling open customer orders; · Verifying whether specific non-standard offerings sought by customers are feasible and supportable; · Checking the credit worthiness of customers as part of the customer order process; · Testing the completed offering to ensure it is working correctly; · Updating of the Customer Inventory Database to reflect that the specific product offering has been allocated, modified, or cancelled; · Assigning and tracking customer provisioning activities; · Managing customer provisioning jeopardy conditions; and · Reporting progress on customer orders and other processes to customer. These applications typically get orders from CRM systems. They interact with network elements and billing systems for fulfillment of orders. 5. Enterprise Management This process area includes those processes that manage enterprise-wide activities and needs, or have application within the enterprise as a whole. They encompass all business management processes that · Are necessary to support the whole of the enterprise, including processes for financial management, legal management, regulatory management, process, cost, and quality management, etc.; · Are responsible for setting corporate policies, strategies, and directions, and for providing guidelines and targets for the whole of the business, including strategy development and planning for areas, such as Enterprise Architecture, that are integral to the direction and development of the business; · Occur throughout the enterprise, including processes for project management, performance assessments, cost assessments, etc. (i) Enterprise Risk Management: Enterprise Risk Management focuses on assuring that risks and threats to the enterprise value and/or reputation are identified, and appropriate controls are in place to minimize or eliminate the identified risks. The identified risks may be physical or logical/virtual. Successful risk management ensures that the enterprise can support its mission critical operations, processes, applications, and communications in the face of serious incidents such as security threats/violations and fraud attempts. Two key areas covered in Risk Management by telecom operators are: · Revenue Assurance: Revenue assurance system will be responsible for identifying revenue loss scenarios across components/systems, and will help in rectifying the problems. The following lists the high-level roles and responsibilities executed by the Revenue Assurance system in the end-to-end solution. o Identify all usage information dropped when networks are being upgraded. o Interconnect bill verification. o Identify where services are routinely provisioned but never billed. o Identify poor sales policies that are intensifying collections problems. o Find leakage where usage is sent to error bucket and never billed for. o Find leakage where field service, CRM, and network build-out are not optimized. · Fraud Management: Involves collecting data from different systems to identify abnormalities in traffic patterns, usage patterns, and subscription patterns to report suspicious activity that might suggest fraudulent usage of resources, resulting in revenue losses to the operator. The key roles and responsibilities of the system component are as follows: o Fraud management system will capture and monitor high usage (over a certain threshold) in terms of duration, value, and number of calls for each subscriber. The threshold for each subscriber is decided by the system and fixed automatically. o Fraud management will be able to detect the unauthorized access to services for certain subscribers. These subscribers may have been provided unauthorized services by employees. The component will raise the alert to the operator the very first time of such illegal calls or calls which are not billed. o The solution will be to have an alarm management system that will deliver alarms to the operator/provider whenever it detects a fraud, thus minimizing fraud by catching it the first time it occurs. o The Fraud Management system will be capable of interfacing with switches, mediation systems, and billing systems (ii) Knowledge Management This process focuses on knowledge management, technology research within the enterprise, and the evaluation of potential technology acquisitions. Key responsibilities of knowledge base management are to · Maintain knowledge base – Creation and updating of knowledge base on ongoing basis. · Search knowledge base – Search of knowledge base on keywords or category browse · Maintain metadata – Management of metadata on knowledge base to ensure effective management and search. · Run report generator. · Provide content – Add content to the knowledge base, e.g., user guides, operational manual, etc. (iii) Document Management It focuses on maintaining a repository of all electronic documents or images of paper documents relevant to the enterprise using a system. (iv) Data Management It manages data as a valuable resource for any enterprise. For telecom enterprises, the typical areas covered are Master Data Management, Data Warehousing, and Business Intelligence. It is also responsible for data governance, security, quality, and database management. Key responsibilities of Data Management are · Using ETL, extract the data from CRM, Billing, web content, ERP, campaign management, financial, network operations, asset management info, customer contact data, customer measures, benchmarks, process data, e.g., process inputs, outputs, and measures, into Enterprise Data Warehouse. · Management of data traceability with source, data related business rules/decisions, data quality, data cleansing data reconciliation, competitors data – storage for all the enterprise data (customer profiles, products, offers, revenues, etc.) · Get online update through night time replication or physical backup process at regular frequency. · Provide the data access to business intelligence and other systems for their analysis, report generation, and use. (v) Business Intelligence It uses the Enterprise Data to provide the various analysis and reports that contain prospects and analytics for customer retention, acquisition of new customers due to the offers, and SLAs. It will generate right and optimized plans – bolt-ons for the customers. The following lists the high-level roles and responsibilities executed by the Business Intelligence system at the Enterprise Level: · It will do Pattern analysis and reports problem. · It will do Data Analysis – Statistical analysis, data profiling, affinity analysis of data, customer segment wise usage patterns on offers, products, service and revenue generation against services and customer segments. · It will do Performance (business, system, and forecast) analysis, churn propensity, response time, and SLAs analysis. · It will support for online and offline analysis, and report drill down capability. · It will collect, store, and report various SLA data. · It will provide the necessary intelligence for marketing and working on campaigns, etc., with cost benefit analysis and predictions. It will advise on customer promotions with additional services based on loyalty and credit history of customer · It will Interface with Enterprise Data Management system for data to run reports and analysis tasks. It will interface with the campaign schedules, based on historical success evidence. (vi) Stakeholder and External Relations Management It manages the enterprise's relationship with stakeholders and outside entities. Stakeholders include shareholders, employee organizations, etc. Outside entities include regulators, local community, and unions. Some of the processes within this grouping are Shareholder Relations, External Affairs, Labor Relations, and Public Relations. (vii) Enterprise Resource Planning It is used to manage internal and external resources, including tangible assets, financial resources, materials, and human resources. Its purpose is to facilitate the flow of information between all business functions inside the boundaries of the enterprise and manage the connections to outside stakeholders. ERP systems consolidate all business operations into a uniform and enterprise wide system environment. The key roles and responsibilities for Enterprise System are given below: · It will handle responsibilities such as core accounting, financial, and management reporting. · It will interface with CRM for capturing customer account and details. · It will interface with billing to capture the billing revenue and other financial data. · It will be responsible for executing the dunning process. Billing will send the required feed to ERP for execution of dunning. · It will interface with the CRM and Billing through batch interfaces. Enterprise management systems are like horizontals in the enterprise and typically interact with all major telecom systems. E.g., an ERP system interacts with CRM, Fulfillment, and Billing systems for different kinds of data exchanges. 6. External Interfaces/Touch Points The typical external parties are customers, suppliers/partners, employees, shareholders, and other stakeholders. External interactions from/to a Service Provider to other parties can be achieved by a variety of mechanisms, including: · Exchange of emails or faxes · Call Centers · Web Portals · Business-to-Business (B2B) automated transactions These applications provide an Internet technology driven interface to external parties to undertake a variety of business functions directly for themselves. These can provide fully or partially automated service to external parties through various touch points. Typical characteristics of these touch points are · Pre-integrated self-service system, including stand-alone web framework or integration front end with a portal engine · Self services layer exposing atomic web services/APIs for reuse by multiple systems across the architectural environment · Portlets driven connectivity exposing data and services interoperability through a portal engine or web application These touch points mostly interact with the CRM systems for requests, inquiries, and responses. 7. Middleware The component will be primarily responsible for integrating the different systems components under a common platform. It should provide a Standards-Based Platform for building Service Oriented Architecture and Composite Applications. The following lists the high-level roles and responsibilities executed by the Middleware component in the end-to-end solution. · As an integration framework, covering to and fro interfaces · Provide a web service framework with service registry. · Support SOA framework with SOA service registry. · Each of the interfaces from / to Middleware to other components would handle data transformation, translation, and mapping of data points. · Receive data from the caller / activate and/or forward the data to the recipient system in XML format. · Use standard XML for data exchange. · Provide the response back to the service/call initiator. · Provide a tracking until the response completion. · Keep a store transitional data against each call/transaction. · Interface through Middleware to get any information that is possible and allowed from the existing systems to enterprise systems; e.g., customer profile and customer history, etc. · Provide the data in a common unified format to the SOA calls across systems, and follow the Enterprise Architecture directive. · Provide an audit trail for all transactions being handled by the component. 8. Network Elements The term Network Element means a facility or equipment used in the provision of a telecommunications service. Such terms also includes features, functions, and capabilities that are provided by means of such facility or equipment, including subscriber numbers, databases, signaling systems, and information sufficient for billing and collection or used in the transmission, routing, or other provision of a telecommunications service. Typical network elements in a GSM network are Home Location Register (HLR), Intelligent Network (IN), Mobile Switching Center (MSC), SMS Center (SMSC), and network elements for other value added services like Push-to-talk (PTT), Ring Back Tone (RBT), etc. Network elements are invoked when subscribers use their telecom devices for any kind of usage. These elements generate usage data and pass it on to downstream systems like mediation and billing system for rating and billing. They also integrate with provisioning systems for order/service fulfillment. 9. 3rd Party Applications 3rd Party systems are applications like content providers, payment gateways, point of sale terminals, and databases/applications maintained by the Government. Depending on applicability and the type of functionality provided by 3rd party applications, the integration with different telecom systems like CRM, provisioning, and billing will be done. 10. Service Delivery Platform A service delivery platform (SDP) provides the architecture for the rapid deployment, provisioning, execution, management, and billing of value added telecom services. SDPs are based on the concept of SOA and layered architecture. They support the delivery of voice, data services, and content in network and device-independent fashion. They allow application developers to aggregate network capabilities, services, and sources of content. SDPs typically contain layers for web services exposure, service application development, and network abstraction. SOA Reference Architecture SOA concept is based on the principle of developing reusable business service and building applications by composing those services, instead of building monolithic applications in silos. It’s about bridging the gap between business and IT through a set of business-aligned IT services, using a set of design principles, patterns, and techniques. In an SOA, resources are made available to participants in a value net, enterprise, line of business (typically spanning multiple applications within an enterprise or across multiple enterprises). It consists of a set of business-aligned IT services that collectively fulfill an organization’s business processes and goals. We can choreograph these services into composite applications and invoke them through standard protocols. SOA, apart from agility and reusability, enables: · The business to specify processes as orchestrations of reusable services · Technology agnostic business design, with technology hidden behind service interface · A contractual-like interaction between business and IT, based on service SLAs · Accountability and governance, better aligned to business services · Applications interconnections untangling by allowing access only through service interfaces, reducing the daunting side effects of change · Reduced pressure to replace legacy and extended lifetime for legacy applications, through encapsulation in services · A Cloud Computing paradigm, using web services technologies, that makes possible service outsourcing on an on-demand, utility-like, pay-per-usage basis The following section represents the Reference Architecture of logical view for the Telecom Solution. The new custom built application needs to align with this logical architecture in the long run to achieve EA benefits. Packaged implementation applications, such as ERP billing applications, need to expose their functions as service providers (as other applications consume) and interact with other applications as service consumers. COT applications need to expose services through wrappers such as adapters to utilize existing resources and at the same time achieve Enterprise Architecture goal and objectives. The following are the various layers for Enterprise level deployment of SOA. This diagram captures the abstract view of Enterprise SOA layers and important components of each layer. Layered architecture means decomposition of services such that most interactions occur between adjacent layers. However, there is no strict rule that top layers should not directly communicate with bottom layers. The diagram below represents the important logical pieces that would result from overall SOA transformation. @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoCaption, li.MsoCaption, div.MsoCaption { margin: 0cm 0cm 10pt; font-size: 9pt; font-family: "Times New Roman"; color: rgb(79, 129, 189); font-weight: bold; }p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpFirst, li.MsoListParagraphCxSpFirst, div.MsoListParagraphCxSpFirst { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpMiddle, li.MsoListParagraphCxSpMiddle, div.MsoListParagraphCxSpMiddle { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }p.MsoListParagraphCxSpLast, li.MsoListParagraphCxSpLast, div.MsoListParagraphCxSpLast { margin: 0cm 0cm 0.0001pt 36pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Figure 3. Enterprise SOA Reference Architecture 1. Operational System Layer: This layer consists of all packaged applications like CRM, ERP, custom built applications, COTS based applications like Billing, Revenue Management, Fulfilment, and the Enterprise databases that are essential and contribute directly or indirectly to the Enterprise OSS/BSS Transformation. ERP holds the data of Asset Lifecycle Management, Supply Chain, and Advanced Procurement and Human Capital Management, etc. CRM holds the data related to Order, Sales, and Marketing, Customer Care, Partner Relationship Management, Loyalty, etc. Content Management handles Enterprise Search and Query. Billing application consists of the following components: · Collections Management, Customer Billing Management, Invoices, Real-Time Rating, Discounting, and Applying of Charges · Enterprise databases will hold both the application and service data, whether structured or unstructured. MDM - Master data majorly consists of Customer, Order, Product, and Service Data. 2. Enterprise Component Layer: This layer consists of the Application Services and Common Services that are responsible for realizing the functionality and maintaining the QoS of the exposed services. This layer uses container-based technologies such as application servers to implement the components, workload management, high availability, and load balancing. Application Services: This Service Layer enables application, technology, and database abstraction so that the complex accessing logic is hidden from the other service layers. This is a basic service layer, which exposes application functionalities and data as reusable services. The three types of the Application access services are: · Application Access Service: This Service Layer exposes application level functionalities as a reusable service between BSS to BSS and BSS to OSS integration. This layer is enabled using disparate technology such as Web Service, Integration Servers, and Adaptors, etc. · Data Access Service: This Service Layer exposes application data services as a reusable reference data service. This is done via direct interaction with application data. and provides the federated query. · Network Access Service: This Service Layer exposes provisioning layer as a reusable service from OSS to OSS integration. This integration service emphasizes the need for high performance, stateless process flows, and distributed design. Common Services encompasses management of structured, semi-structured, and unstructured data such as information services, portal services, interaction services, infrastructure services, and security services, etc. 3. Integration Layer: This consists of service infrastructure components like service bus, service gateway for partner integration, service registry, service repository, and BPEL processor. Service bus will carry the service invocation payloads/messages between consumers and providers. The other important functions expected from it are itinerary based routing, distributed caching of routing information, transformations, and all qualities of service for messaging-like reliability, scalability, and availability, etc. Service registry will hold all contracts (wsdl) of services, and it helps developers to locate or discover service during design time or runtime. • BPEL processor would be useful in orchestrating the services to compose a complex business scenario or process. • Workflow and business rules management are also required to support manual triggering of certain activities within business process. based on the rules setup and also the state machine information. Application, data, and service mediation layer typically forms the overall composite application development framework or SOA Framework. 4. Business Process Layer: These are typically the intermediate services layer and represent Shared Business Process Services. At Enterprise Level, these services are from Customer Management, Order Management, Billing, Finance, and Asset Management application domains. 5. Access Layer: This layer consists of portals for Enterprise and provides a single view of Enterprise information management and dashboard services. 6. Channel Layer: This consists of various devices; applications that form part of extended enterprise; browsers through which users access the applications. 7. Client Layer: This designates the different types of users accessing the enterprise applications. The type of user typically would be an important factor in determining the level of access to applications. 8. Vertical pieces like management, monitoring, security, and development cut across all horizontal layers Management and monitoring involves all aspects of SOA-like services, SLAs, and other QoS lifecycle processes for both applications and services surrounding SOA governance. 9. EA Governance, Reference Architecture, Roadmap, Principles, and Best Practices: EA Governance is important in terms of providing the overall direction to SOA implementation within the enterprise. This involves board-level involvement, in addition to business and IT executives. At a high level, this involves managing the SOA projects implementation, managing SOA infrastructure, and controlling the entire effort through all fine-tuned IT processes in accordance with COBIT (Control Objectives for Information Technology). Devising tools and techniques to promote reuse culture, and the SOA way of doing things needs competency centers to be established in addition to training the workforce to take up new roles that are suited to SOA journey. Conclusions Reference Architectures can serve as the basis for disparate architecture efforts throughout the organization, even if they use different tools and technologies. Reference architectures provide best practices and approaches in the independent way a vendor deals with technology and standards. Reference Architectures model the abstract architectural elements for an enterprise independent of the technologies, protocols, and products that are used to implement an SOA. Telecom enterprises today are facing significant business and technology challenges due to growing competition, a multitude of services, and convergence. Adopting architectural best practices could go a long way in meeting these challenges. The use of SOA-based architecture for communication to each of the external systems like Billing, CRM, etc., in OSS/BSS system has made the architecture very loosely coupled, with greater flexibility. Any change in the external systems would be absorbed at the Integration Layer without affecting the rest of the ecosystem. The use of a Business Process Management (BPM) tool makes the management and maintenance of the business processes easy, with better performance in terms of lead time, quality, and cost. Since the Architecture is based on standards, it will lower the cost of deploying and managing OSS/BSS applications over their lifecycles.

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Creating a dynamic proxy generator – Part 1 – Creating the Assembly builder, Module builder and cach

- by SeanMcAlinden

I’ve recently started a project with a few mates to learn the ins and outs of Dependency Injection, AOP and a number of other pretty crucial patterns of development as we’ve all been using these patterns for a while but have relied totally on third part solutions to do the magic. We thought it would be interesting to really get into the details by rolling our own IoC container and hopefully learn a lot on the way, and you never know, we might even create an excellent framework. The open source project is called Rapid IoC and is hosted at http://rapidioc.codeplex.com/ One of the most interesting tasks for me is creating the dynamic proxy generator for enabling Aspect Orientated Programming (AOP). In this series of articles, I’m going to track each step I take for creating the dynamic proxy generator and I’ll try my best to explain what everything means - mainly as I’ll be using Reflection.Emit to emit a fair amount of intermediate language code (IL) to create the proxy types at runtime which can be a little taxing to read. It’s worth noting that building the proxy is without a doubt going to be slightly painful so I imagine there will be plenty of areas I’ll need to change along the way. Anyway lets get started… Part 1 - Creating the Assembly builder, Module builder and caching mechanism Part 1 is going to be a really nice simple start, I’m just going to start by creating the assembly, module and type caches. The reason we need to create caches for the assembly, module and types is simply to save the overhead of recreating proxy types that have already been generated, this will be one of the important steps to ensure that the framework is fast… kind of important as we’re calling the IoC container ‘Rapid’ – will be a little bit embarrassing if we manage to create the slowest framework. The Assembly builder The assembly builder is what is used to create an assembly at runtime, we’re going to have two overloads, one will be for the actual use of the proxy generator, the other will be mainly for testing purposes as it will also save the assembly so we can use Reflector to examine the code that has been created. Here’s the code: DynamicAssemblyBuilder using System; using System.Reflection; using System.Reflection.Emit; namespace Rapid.DynamicProxy.Assembly { /// <summary> /// Class for creating an assembly builder. /// </summary> internal static class DynamicAssemblyBuilder { #region Create /// <summary> /// Creates an assembly builder. /// </summary> /// <param name="assemblyName">Name of the assembly.</param> public static AssemblyBuilder Create(string assemblyName) { AssemblyName name = new AssemblyName(assemblyName); AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly( name, AssemblyBuilderAccess.Run); DynamicAssemblyCache.Add(assembly); return assembly; } /// <summary> /// Creates an assembly builder and saves the assembly to the passed in location. /// </summary> /// <param name="assemblyName">Name of the assembly.</param> /// <param name="filePath">The file path.</param> public static AssemblyBuilder Create(string assemblyName, string filePath) { AssemblyName name = new AssemblyName(assemblyName); AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly( name, AssemblyBuilderAccess.RunAndSave, filePath); DynamicAssemblyCache.Add(assembly); return assembly; } #endregion } } So hopefully the above class is fairly explanatory, an AssemblyName is created using the passed in string for the actual name of the assembly. An AssemblyBuilder is then constructed with the current AppDomain and depending on the overload used, it is either just run in the current context or it is set up ready for saving. It is then added to the cache. DynamicAssemblyCache using System.Reflection.Emit; using Rapid.DynamicProxy.Exceptions; using Rapid.DynamicProxy.Resources.Exceptions; namespace Rapid.DynamicProxy.Assembly { /// <summary> /// Cache for storing the dynamic assembly builder. /// </summary> internal static class DynamicAssemblyCache { #region Declarations private static object syncRoot = new object(); internal static AssemblyBuilder Cache = null; #endregion #region Adds a dynamic assembly to the cache. /// <summary> /// Adds a dynamic assembly builder to the cache. /// </summary> /// <param name="assemblyBuilder">The assembly builder.</param> public static void Add(AssemblyBuilder assemblyBuilder) { lock (syncRoot) { Cache = assemblyBuilder; } } #endregion #region Gets the cached assembly /// <summary> /// Gets the cached assembly builder. /// </summary> /// <returns></returns> public static AssemblyBuilder Get { get { lock (syncRoot) { if (Cache != null) { return Cache; } } throw new RapidDynamicProxyAssertionException(AssertionResources.NoAssemblyInCache); } } #endregion } } The cache is simply a static property that will store the AssemblyBuilder (I know it’s a little weird that I’ve made it public, this is for testing purposes, I know that’s a bad excuse but hey…) There are two methods for using the cache – Add and Get, these just provide thread safe access to the cache. The Module Builder The module builder is required as the create proxy classes will need to live inside a module within the assembly. Here’s the code: DynamicModuleBuilder using System.Reflection.Emit; using Rapid.DynamicProxy.Assembly; namespace Rapid.DynamicProxy.Module { /// <summary> /// Class for creating a module builder. /// </summary> internal static class DynamicModuleBuilder { /// <summary> /// Creates a module builder using the cached assembly. /// </summary> public static ModuleBuilder Create() { string assemblyName = DynamicAssemblyCache.Get.GetName().Name; ModuleBuilder moduleBuilder = DynamicAssemblyCache.Get.DefineDynamicModule (assemblyName, string.Format("{0}.dll", assemblyName)); DynamicModuleCache.Add(moduleBuilder); return moduleBuilder; } } } As you can see, the module builder is created on the assembly that lives in the DynamicAssemblyCache, the module is given the assembly name and also a string representing the filename if the assembly is to be saved. It is then added to the DynamicModuleCache. DynamicModuleCache using System.Reflection.Emit; using Rapid.DynamicProxy.Exceptions; using Rapid.DynamicProxy.Resources.Exceptions; namespace Rapid.DynamicProxy.Module { /// <summary> /// Class for storing the module builder. /// </summary> internal static class DynamicModuleCache { #region Declarations private static object syncRoot = new object(); internal static ModuleBuilder Cache = null; #endregion #region Add /// <summary> /// Adds a dynamic module builder to the cache. /// </summary> /// <param name="moduleBuilder">The module builder.</param> public static void Add(ModuleBuilder moduleBuilder) { lock (syncRoot) { Cache = moduleBuilder; } } #endregion #region Get /// <summary> /// Gets the cached module builder. /// </summary> /// <returns></returns> public static ModuleBuilder Get { get { lock (syncRoot) { if (Cache != null) { return Cache; } } throw new RapidDynamicProxyAssertionException(AssertionResources.NoModuleInCache); } } #endregion } } The DynamicModuleCache is very similar to the assembly cache, it is simply a statically stored module with thread safe Add and Get methods. The DynamicTypeCache To end off this post, I’m going to create the cache for storing the generated proxy classes. I’ve spent a fair amount of time thinking about the type of collection I should use to store the types and have finally decided that for the time being I’m going to use a generic dictionary. This may change when I can actually performance test the proxy generator but the time being I think it makes good sense in theory, mainly as it pretty much maintains it’s performance with varying numbers of items – almost constant (0)1. Plus I won’t ever need to loop through the items which is not the dictionaries strong point. Here’s the code as it currently stands: DynamicTypeCache using System; using System.Collections.Generic; using System.Security.Cryptography; using System.Text; namespace Rapid.DynamicProxy.Types { /// <summary> /// Cache for storing proxy types. /// </summary> internal static class DynamicTypeCache { #region Declarations static object syncRoot = new object(); public static Dictionary<string, Type> Cache = new Dictionary<string, Type>(); #endregion /// <summary> /// Adds a proxy to the type cache. /// </summary> /// <param name="type">The type.</param> /// <param name="proxy">The proxy.</param> public static void AddProxyForType(Type type, Type proxy) { lock (syncRoot) { Cache.Add(GetHashCode(type.AssemblyQualifiedName), proxy); } } /// <summary> /// Tries the type of the get proxy for. /// </summary> /// <param name="type">The type.</param> /// <returns></returns> public static Type TryGetProxyForType(Type type) { lock (syncRoot) { Type proxyType; Cache.TryGetValue(GetHashCode(type.AssemblyQualifiedName), out proxyType); return proxyType; } } #region Private Methods private static string GetHashCode(string fullName) { SHA1CryptoServiceProvider provider = new SHA1CryptoServiceProvider(); Byte[] buffer = Encoding.UTF8.GetBytes(fullName); Byte[] hash = provider.ComputeHash(buffer, 0, buffer.Length); return Convert.ToBase64String(hash); } #endregion } } As you can see, there are two public methods, one for adding to the cache and one for getting from the cache. Hopefully they should be clear enough, the Get is a TryGet as I do not want the dictionary to throw an exception if a proxy doesn’t exist within the cache. Other than that I’ve decided to create a key using the SHA1CryptoServiceProvider, this may change but my initial though is the SHA1 algorithm is pretty fast to put together using the provider and it is also very unlikely to have any hashing collisions. (there are some maths behind how unlikely this is – here’s the wiki if you’re interested http://en.wikipedia.org/wiki/SHA_hash_functions) Anyway, that’s the end of part 1 – although I haven’t started any of the fun stuff (by fun I mean hairpulling, teeth grating Relfection.Emit style fun), I’ve got the basis of the DynamicProxy in place so all we have to worry about now is creating the types, interceptor classes, method invocation information classes and finally a really nice fluent interface that will abstract all of the hard-core craziness away and leave us with a lightning fast, easy to use AOP framework. Hope you find the series interesting. All of the source code can be viewed and/or downloaded at our codeplex site - http://rapidioc.codeplex.com/ Kind Regards, Sean.

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Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

- by mortezam

This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail { public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } public class BankAccount : BillingDetail { public string BankName { get; set; } public string Swift { get; set; } } public class CreditCard : BillingDetail { public int CardType { get; set; } public string ExpiryMonth { get; set; } public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext { public DbSet<BillingDetail> BillingDetails { get; set; } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<BankAccount>().Map(m => { m.MapInheritedProperties(); m.ToTable("BankAccounts"); }); modelBuilder.Entity<CreditCard>().Map(m => { m.MapInheritedProperties(); m.ToTable("CreditCards"); }); } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping { public class EntityMappingConfiguration<TEntityType> where TEntityType : class { public ValueConditionConfiguration Requires(string discriminator); public void ToTable(string tableName); public void MapInheritedProperties(); } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) { BankAccount bankAccount = new BankAccount(); CreditCard creditCard = new CreditCard() { CardType = 1 }; context.BillingDetails.Add(bankAccount); context.BillingDetails.Add(creditCard); context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail { [DatabaseGenerated(DatabaseGenerationOption.None)] public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>() .Property(p => p.BillingDetailId) .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) { BankAccount bankAccount = new BankAccount() { BillingDetailId = 1 }; CreditCard creditCard = new CreditCard() { BillingDetailId = 2, CardType = 1 }; context.BillingDetails.Add(bankAccount); context.BillingDetails.Add(creditCard); context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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CodePlex Daily Summary for Sunday, November 13, 2011

CodePlex Daily Summary for Sunday, November 13, 2011Popular ReleasesT.S.T. the T-SQL Test Tool: Version 1.8: Implement the Assert.Ignore API. Fix a bug: A test session is reported as passing if only the test session setup or test session teardown failed. Improve the text and xml output when test session setup/teardown are present. Allow users to customize the prefix "SQLTest_".VidCoder: 1.2.2: Updated Handbrake core to svn 4344. Fixed the 6-channel discrete mixdown option not appearing for AAC encoders. Added handling for possible exceptions when copying to the clipboard, added retries and message when it fails. Fixed issue with audio bitrate UI not appearing sometimes when switching audio encoders. Added extra checks to protect against reported crashes. Added code to upgrade encoding profiles on old queued items.Dynamic PagedCollection (Silverlight / WPF Pagination): PagedCollection: All classes which facilitate your dynamic pagination in Silverlight or WPF !Media Companion: MC 3.422b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) TV Show Resolutions... Made the TV Shows folder list sorted. Re-visibled 'Manually Add Path' in Root Folders. Sorted list to process during new tv episode search Rebuild Movies now processes thru folders alphabetically Fix for issue #208 - Display Missing Episodes is not popu...DotSpatial: DotSpatial Release Candidate 1 (1.0.823): Supports loading extensions using System.ComponentModel.Composition. DemoMap compiled as x86 so that GDAL runs on x64 machines. How to: Use an Assembly from the WebBe aware that your browser may add an identifier to downloaded files which results in "blocked" dll files. You can follow the following link to learn how to "Unblock" files. Right click on the zip file before unzipping, choose properties, go to the general tab and click the unblock button. http://msdn.microsoft.com/en-us/library...XPath Visualizer: XPathVisualizer v1.3 Latest: This is v1.3.0.6 of XpathVisualizer. This is an update release for v1.3. These workitems have been fixed since v1.3.0.5: 7429 7432 7427MSBuild Extension Pack: November 2011: Release Blog Post The MSBuild Extension Pack November 2011 release provides a collection of over 415 MSBuild tasks. A high level summary of what the tasks currently cover includes the following: System Items: Active Directory, Certificates, COM+, Console, Date and Time, Drives, Environment Variables, Event Logs, Files and Folders, FTP, GAC, Network, Performance Counters, Registry, Services, Sound Code: Assemblies, AsyncExec, CAB Files, Code Signing, DynamicExecute, File Detokenisation, GU...CODE Framework: 4.0.11110.0: Various minor fixes and tweaks.Extensions for Reactive Extensions (Rxx): Rxx 1.2: What's NewRelated Work Items Please read the latest release notes for details about what's new. Content SummaryRxx provides the following features. See the Documentation for details. Many IObservable<T> extension methods and IEnumerable<T> extension methods. Many useful types such as ViewModel, CommandSubject, ListSubject, DictionarySubject, ObservableDynamicObject, Either<TLeft, TRight>, Maybe<T> and others. Various interactive labs that illustrate the runtime behavior of the extensio...Player Framework by Microsoft: HTML5 Player Framework 1.0: Additional DownloadsHTML5 Player Framework Examples - This is a set of examples showing how to setup and initialize the HTML5 Player Framework. This includes examples of how to use the Player Framework with both the HTML5 video tag and Silverlight player. Note: Be sure to unblock the zip file before using. Note: In order to test Silverlight fallback in the included sample app, you need to run the html and xap files over http (e.g. over localhost). Silverlight Players - Visit the Silverlig...MapWindow 4: MapWindow GIS v4.8.6 - Final release - 64Bit: What’s New in 4.8.6 (Final release)A few minor issues have been fixed What’s New in 4.8.5 (Beta release)Assign projection tool. (Sergei Leschinsky) Projection dialects. (Sergei Leschinsky) Projections database converted to SQLite format. (Sergei Leschinsky) Basic code for database support - will be developed further (ShapefileDataClient class, IDataProvider interface). (Sergei Leschinsky) 'Export shapefile to database' tool. (Sergei Leschinsky) Made the GEOS library static. geos.dl...Facebook C# SDK: v5.3.2: This is a RTW release which adds new features and bug fixes to v5.2.1. Query/QueryAsync methods uses graph api instead of legacy rest api. removed dependency from Code Contracts enabled Task Parallel Support in .NET 4.0+ (experimental) added support for early preview for .NET 4.5 (binaries not distributed in codeplex nor nuget.org, will need to manually build from Facebook-Net45.sln) added additional method overloads for .NET 4.5 to support IProgress<T> for upload progress added ne...Delete Inactive TS Ports: List and delete the Inactive TS Ports: UPDATEAdded support for windows 2003 servers and removed some null reference errors when the registry key was not present List and delete the Inactive TS Ports - The InactiveTSPortList.EXE accepts command line arguments The InactiveTSPortList.Standalone.WithoutPrompt.exe runs as a standalone exe without the need for any command line arguments.ClosedXML - The easy way to OpenXML: ClosedXML 0.60.0: Added almost full support for auto filters (missing custom date filters). See examples Filter Values, Custom Filters Fixed issues 7016, 7391, 7388, 7389, 7198, 7196, 7194, 7186, 7067, 7115, 7144Microsoft Research Boogie: Nightly builds: This download category contains automatically released nightly builds, reflecting the current state of Boogie's development. We try to make sure each nightly build passes the test suite. If you suspect that was not the case, please try the previous nightly build to see if that really is the problem. Also, please see the installation instructions.GoogleMap Control: GoogleMap Control 6.0: Major design changes to the control in order to achieve better scalability and extensibility for the new features comming with GoogleMaps API. GoogleMap control switched to GoogleMaps API v3 and .NET 4.0. GoogleMap control is 100% ScriptControl now, it requires ScriptManager to be registered on the pages where and before it is used. Markers, polylines, polygons and directions were implemented as ExtenderControl, instead of being inner properties of GoogleMap control. Better perfomance. Better...WabbitStudio Z80 Software Tools: WabbitCode Mac 2.1: WabbitCode for the Mac version 2.1. You need 10.7 (Lion) to run this. There won't be any further releases for older versions of OS X.Shell Sort Web service and Application: Shell sort Web service and application: Shell Sort WebserviceSharePoint Backup Augmentation Cmdlets: SharePointBAC Technology Preview: This release is purely an opportunity for administrators who live on the bleeding-edge to "kick the tires." Only two cmdlets are available: Get-SPBackupCatalog and Remove-SPBackupCatalog. Both of these cmdlets are fully functional and documented in their current form, but the cmdlets have seen little testing and real-world use thus far. The code, capabilities, and reliability of this project will evolve in the weeks and months ahead, but for now you should avoid deploying these cmdlets to pro...WDTVHubGen - Adds Metadata, thumbnails and subtitles to WDTV Live Hubs: V2.1: Version 2.1 (click on the right) this uses V4.0 of .net Version 2.1 adds the following features: (apologize if I forget some, added a lot of little things) Manual Lookup with TV or Movie (finally huh!), you can look up a movie or TV episode directly, you can right click on anythign, and choose manual lookup, then will allow you to type anything you want to look up and it will assign it to the file you right clicked. No Rename: a very popular request, this is an option you can set so that t...New ProjectsBTG - Bilateral Tower Guardians: BIEN TA GROTTEc# Extended Link List: The ExtendedLinkList Graffiti CMS Widget is a C# port of an existing widget by Curt C at http://www.codeplex.com/ExtendedLinkListCodePubs: codepubs DegradingLoad: DegradingLoad will attempt to load a process serverside async; if it takes too long it will "degrade" to using clientside ajax to retrieve the result without blocking the main page contentDino: Dino is a simple ORM wrapper framework that provides a consistent set of interfaces for working with a variety of ORMs in a single Unit of Work. Dino is built to be extremely lightweight, with built in support for abstracting away some of the intricicies of using various ORMs.Elenoire: Elenoire is a live bot assistant for everyday that takes a appointment and note for you, the bot work when you are not present on messenger. Fontus: Fontus è un sistema centralizzato per l’erogazione di contenuti informativi. Il sistema Fontus si basa su un meccanismo di plug-in per rendere l’insieme delle fonti estendibile. FoolFish.CodeBase: implement your especial ideas...FullonSMS Desktop Client: Send free sms using fullonsms by this software to anywhere in India, supports grouping and contacts feature. Developed by Ayush PateriaInterface Interceptor: Allows you to filter and intercept interface methods.NBouncer: NBouncer is a Context Aware Validation framework without attributes for .NET 3.5 Winforms, WPF, Silverlight or Asp.NET MVCNetShips: Simple network battleship game for 2 players.Nhung Nai Website: phát tri?n Nhung Nai WebisteOpenCV2.2 Project template For Visual Studio 2010: The intension of the project is to make your life little easier if you use OpenCV2.2. As i couldn't find a project template for OpenCV, I decided to publish it on codeplex. Hope it will help at least some of you.Projeto de Compiladores: Projeto de Compiladores da Unicap 2011.2sejce2008: jce se course wiki and projects linksSharpener: Sharpener is a simple optimizer for .NET and Mono.Simple Live Screen: Simple Live Screen's target is to fasten screen transmits by using it's own protocol. This program is being developed in C#.Simple Note XML - ASP.NET User Control: Simple Note XML makes it easier for ASP.NET Developers to build lists. You'll no longer have to write things down. It's developed in ASP.NET 2.0 C#. SquadLead for Tasks - Community Edition: SquadLead Tasks Community Edition is a PostGreSQL based Task Management software for teams, with wonderful time and resource allocation abilities. Unlinke Gannt charting and dependency abilities, SquadLead gives a flexibility to create ad-hoc tasks with no dependencies and hence suits many different kind of projects in a versatile way. If you take care of dependencies, it takes care of helping you with identifying allocation loads, reports and graphs. Features Task Management and...Stanford db-class algorithms: The algorithms of the relational db theory, described in the introduction to databases Stanford class (www.db-class.org).tfsProjectInitialiser: After creating a Team Project, load the initial state of the project - complete with Areas, Iterations, Work Items - quickly and easily. I am on my one on this so far, so any help or contribution would be appreciated.

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Adding SQL Cache Dependencies to the Loosely coupled .NET Cache Provider

- by Rhames

This post adds SQL Cache Dependency support to the loosely coupled .NET Cache Provider that I described in the previous post (http://geekswithblogs.net/Rhames/archive/2012/09/11/loosely-coupled-.net-cache-provider-using-dependency-injection.aspx). The sample code is available on github at https://github.com/RobinHames/CacheProvider.git. Each time we want to apply a cache dependency to a call to fetch or cache a data item we need to supply an instance of the relevant dependency implementation. This suggests an Abstract Factory will be useful to create cache dependencies as needed. We can then use Dependency Injection to inject the factory into the relevant consumer. Castle Windsor provides a typed factory facility that will be utilised to implement the cache dependency abstract factory (see http://docs.castleproject.org/Windsor.Typed-Factory-Facility-interface-based-factories.ashx). Cache Dependency Interfaces First I created a set of cache dependency interfaces in the domain layer, which can be used to pass a cache dependency into the cache provider. ICacheDependency The ICacheDependency interface is simply an empty interface that is used as a parent for the specific cache dependency interfaces. This will allow us to place a generic constraint on the Cache Dependency Factory, and will give us a type that can be passed into the relevant Cache Provider methods. namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheDependency { } } ISqlCacheDependency.cs The ISqlCacheDependency interface provides specific SQL caching details, such as a Sql Command or a database connection and table. It is the concrete implementation of this interface that will be created by the factory in passed into the Cache Provider. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace CacheDiSample.Domain.CacheInterfaces { public interface ISqlCacheDependency : ICacheDependency { ISqlCacheDependency Initialise(string databaseConnectionName, string tableName); ISqlCacheDependency Initialise(System.Data.SqlClient.SqlCommand sqlCommand); } } If we want other types of cache dependencies, such as by key or file, interfaces may be created to support these (the sample code includes an IKeyCacheDependency interface). Modifying ICacheProvider to accept Cache Dependencies Next I modified the exisitng ICacheProvider<T> interface so that cache dependencies may be passed into a Fetch method call. I did this by adding two overloads to the existing Fetch methods, which take an IEnumerable<ICacheDependency> parameter (the IEnumerable allows more than one cache dependency to be included). I also added a method to create cache dependencies. This means that the implementation of the Cache Provider will require a dependency on the Cache Dependency Factory. It is pretty much down to personal choice as to whether this approach is taken, or whether the Cache Dependency Factory is injected directly into the repository or other consumer of Cache Provider. I think, because the cache dependency cannot be used without the Cache Provider, placing the dependency on the factory into the Cache Provider implementation is cleaner. ICacheProvider.cs using System; using System.Collections.Generic; namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheProvider<T> { T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies); U CreateCacheDependency() where U : ICacheDependency; } } Cache Dependency Factory Next I created the interface for the Cache Dependency Factory in the domain layer. ICacheDependencyFactory.cs namespace CacheDiSample.Domain.CacheInterfaces { public interface ICacheDependencyFactory { T Create<T>() where T : ICacheDependency; void Release<T>(T cacheDependency) where T : ICacheDependency; } } I used the ICacheDependency parent interface as a generic constraint on the create and release methods in the factory interface. Now the interfaces are in place, I moved on to the concrete implementations. ISqlCacheDependency Concrete Implementation The concrete implementation of ISqlCacheDependency will need to provide an instance of System.Web.Caching.SqlCacheDependency to the Cache Provider implementation. Unfortunately this class is sealed, so I cannot simply inherit from this. Instead, I created an interface called IAspNetCacheDependency that will provide a Create method to create an instance of the relevant System.Web.Caching Cache Dependency type. This interface is specific to the ASP.NET implementation of the Cache Provider, so it should be defined in the same layer as the concrete implementation of the Cache Provider (the MVC UI layer in the sample code). IAspNetCacheDependency.cs using System.Web.Caching; namespace CacheDiSample.CacheProviders { public interface IAspNetCacheDependency { CacheDependency CreateAspNetCacheDependency(); } } Next, I created the concrete implementation of the ISqlCacheDependency interface. This class also implements the IAspNetCacheDependency interface. This concrete implementation also is defined in the same layer as the Cache Provider implementation. AspNetSqlCacheDependency.cs using System.Web.Caching; using CacheDiSample.Domain.CacheInterfaces; namespace CacheDiSample.CacheProviders { public class AspNetSqlCacheDependency : ISqlCacheDependency, IAspNetCacheDependency { private string databaseConnectionName; private string tableName; private System.Data.SqlClient.SqlCommand sqlCommand; #region ISqlCacheDependency Members public ISqlCacheDependency Initialise(string databaseConnectionName, string tableName) { this.databaseConnectionName = databaseConnectionName; this.tableName = tableName; return this; } public ISqlCacheDependency Initialise(System.Data.SqlClient.SqlCommand sqlCommand) { this.sqlCommand = sqlCommand; return this; } #endregion #region IAspNetCacheDependency Members public System.Web.Caching.CacheDependency CreateAspNetCacheDependency() { if (sqlCommand != null) return new SqlCacheDependency(sqlCommand); else return new SqlCacheDependency(databaseConnectionName, tableName); } #endregion } } ICacheProvider Concrete Implementation The ICacheProvider interface is implemented by the CacheProvider class. This implementation is modified to include the changes to the ICacheProvider interface. First I needed to inject the Cache Dependency Factory into the Cache Provider: private ICacheDependencyFactory cacheDependencyFactory; public CacheProvider(ICacheDependencyFactory cacheDependencyFactory) { if (cacheDependencyFactory == null) throw new ArgumentNullException("cacheDependencyFactory"); this.cacheDependencyFactory = cacheDependencyFactory; } Next I implemented the CreateCacheDependency method, which simply passes on the create request to the factory: public U CreateCacheDependency() where U : ICacheDependency { return this.cacheDependencyFactory.Create(); } The signature of the FetchAndCache helper method was modified to take an additional IEnumerable<ICacheDependency> parameter: private U FetchAndCache(string key, Func retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) and the following code added to create the relevant System.Web.Caching.CacheDependency object for any dependencies and pass them to the HttpContext Cache: CacheDependency aspNetCacheDependencies = null; if (cacheDependencies != null) { if (cacheDependencies.Count() == 1) // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aspNetCacheDependencies = ((IAspNetCacheDependency)cacheDependencies.ElementAt(0)).CreateAspNetCacheDependency(); else if (cacheDependencies.Count() > 1) { AggregateCacheDependency aggregateCacheDependency = new AggregateCacheDependency(); foreach (ICacheDependency cacheDependency in cacheDependencies) { // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aggregateCacheDependency.Add(((IAspNetCacheDependency)cacheDependency).CreateAspNetCacheDependency()); } aspNetCacheDependencies = aggregateCacheDependency; } } HttpContext.Current.Cache.Insert(key, value, aspNetCacheDependencies, absoluteExpiry.Value, relativeExpiry.Value); The full code listing for the modified CacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching; using CacheDiSample.Domain.CacheInterfaces; namespace CacheDiSample.CacheProviders { public class CacheProvider<T> : ICacheProvider<T> { private ICacheDependencyFactory cacheDependencyFactory; public CacheProvider(ICacheDependencyFactory cacheDependencyFactory) { if (cacheDependencyFactory == null) throw new ArgumentNullException("cacheDependencyFactory"); this.cacheDependencyFactory = cacheDependencyFactory; } public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry, null); } public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry, cacheDependencies); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry, null); } public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry, cacheDependencies); } public U CreateCacheDependency() where U : ICacheDependency { return this.cacheDependencyFactory.Create(); } #region Helper Methods private U FetchAndCache(string key, Func retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry, IEnumerable<ICacheDependency> cacheDependencies) { U value; if (!TryGetValue(key, out value)) { value = retrieveData(); if (!absoluteExpiry.HasValue) absoluteExpiry = Cache.NoAbsoluteExpiration; if (!relativeExpiry.HasValue) relativeExpiry = Cache.NoSlidingExpiration; CacheDependency aspNetCacheDependencies = null; if (cacheDependencies != null) { if (cacheDependencies.Count() == 1) // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aspNetCacheDependencies = ((IAspNetCacheDependency)cacheDependencies.ElementAt(0)).CreateAspNetCacheDependency(); else if (cacheDependencies.Count() > 1) { AggregateCacheDependency aggregateCacheDependency = new AggregateCacheDependency(); foreach (ICacheDependency cacheDependency in cacheDependencies) { // We know that the implementations of ICacheDependency will also implement IAspNetCacheDependency // so we can use a cast here and call the CreateAspNetCacheDependency() method aggregateCacheDependency.Add( ((IAspNetCacheDependency)cacheDependency).CreateAspNetCacheDependency()); } aspNetCacheDependencies = aggregateCacheDependency; } } HttpContext.Current.Cache.Insert(key, value, aspNetCacheDependencies, absoluteExpiry.Value, relativeExpiry.Value); } return value; } private bool TryGetValue(string key, out U value) { object cachedValue = HttpContext.Current.Cache.Get(key); if (cachedValue == null) { value = default(U); return false; } else { try { value = (U)cachedValue; return true; } catch { value = default(U); return false; } } } #endregion } } Wiring up the DI Container Now the implementations for the Cache Dependency are in place, I wired them up in the existing Windsor CacheInstaller. First I needed to register the implementation of the ISqlCacheDependency interface: container.Register( Component.For<ISqlCacheDependency>() .ImplementedBy<AspNetSqlCacheDependency>() .LifestyleTransient()); Next I registered the Cache Dependency Factory. Notice that I have not implemented the ICacheDependencyFactory interface. Castle Windsor will do this for me by using the Type Factory Facility. I do need to bring the Castle.Facilities.TypedFacility namespace into scope: using Castle.Facilities.TypedFactory; Then I registered the factory: container.AddFacility<TypedFactoryFacility>(); container.Register( Component.For<ICacheDependencyFactory>() .AsFactory()); The full code for the CacheInstaller class is: using Castle.MicroKernel.Registration; using Castle.MicroKernel.SubSystems.Configuration; using Castle.Windsor; using Castle.Facilities.TypedFactory; using CacheDiSample.Domain.CacheInterfaces; using CacheDiSample.CacheProviders; namespace CacheDiSample.WindsorInstallers { public class CacheInstaller : IWindsorInstaller { public void Install(IWindsorContainer container, IConfigurationStore store) { container.Register( Component.For(typeof(ICacheProvider<>)) .ImplementedBy(typeof(CacheProvider<>)) .LifestyleTransient()); container.Register( Component.For<ISqlCacheDependency>() .ImplementedBy<AspNetSqlCacheDependency>() .LifestyleTransient()); container.AddFacility<TypedFactoryFacility>(); container.Register( Component.For<ICacheDependencyFactory>() .AsFactory()); } } } Configuring the ASP.NET SQL Cache Dependency There are a couple of configuration steps required to enable SQL Cache Dependency for the application and database. From the Visual Studio Command Prompt, the following commands should be used to enable the Cache Polling of the relevant database tables: aspnet_regsql -S <servername> -E -d <databasename> –ed aspnet_regsql -S <servername> -E -d CacheSample –et –t <tablename> (The –t option should be repeated for each table that is to be made available for cache dependencies). Finally the SQL Cache Polling needs to be enabled by adding the following configuration to the <system.web> section of web.config: <caching> <sqlCacheDependency pollTime="10000" enabled="true"> <databases> <add name="BloggingContext" connectionStringName="BloggingContext"/> </databases> </sqlCacheDependency> </caching> (obviously the name and connection string name should be altered as required). Using a SQL Cache Dependency Now all the coding is complete. To specify a SQL Cache Dependency, I can modify my BlogRepositoryWithCaching decorator class (see the earlier post) as follows: public IList<Blog> GetAll() { var sqlCacheDependency = cacheProvider.CreateCacheDependency<ISqlCacheDependency>() .Initialise("BloggingContext", "Blogs"); ICacheDependency[] cacheDependencies = new ICacheDependency[] { sqlCacheDependency }; string key = string.Format("CacheDiSample.DataAccess.GetAll"); return cacheProvider.Fetch(key, () => { return parentBlogRepository.GetAll(); }, null, null, cacheDependencies) .ToList(); } This will add a dependency of the “Blogs” table in the database. The data will remain in the cache until the contents of this table change, then the cache item will be invalidated, and the next call to the GetAll() repository method will be routed to the parent repository to refresh the data from the database.

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A ToDynamic() Extension Method For Fluent Reflection

- by Dixin

Recently I needed to demonstrate some code with reflection, but I felt it inconvenient and tedious. To simplify the reflection coding, I created a ToDynamic() extension method. The source code can be downloaded from here. Problem One example for complex reflection is in LINQ to SQL. The DataContext class has a property Privider, and this Provider has an Execute() method, which executes the query expression and returns the result. Assume this Execute() needs to be invoked to query SQL Server database, then the following code will be expected: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // Executes the query. Here reflection is required, // because Provider, Execute(), and ReturnValue are not public members. IEnumerable<Product> results = database.Provider.Execute(query.Expression).ReturnValue; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } Of course, this code cannot compile. And, no one wants to write code like this. Again, this is just an example of complex reflection. using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider PropertyInfo providerProperty = database.GetType().GetProperty( "Provider", BindingFlags.NonPublic | BindingFlags.GetProperty | BindingFlags.Instance); object provider = providerProperty.GetValue(database, null); // database.Provider.Execute(query.Expression) // Here GetMethod() cannot be directly used, // because Execute() is a explicitly implemented interface method. Assembly assembly = Assembly.Load("System.Data.Linq"); Type providerType = assembly.GetTypes().SingleOrDefault( type => type.FullName == "System.Data.Linq.Provider.IProvider"); InterfaceMapping mapping = provider.GetType().GetInterfaceMap(providerType); MethodInfo executeMethod = mapping.InterfaceMethods.Single(method => method.Name == "Execute"); IExecuteResult executeResult = executeMethod.Invoke(provider, new object[] { query.Expression }) as IExecuteResult; // database.Provider.Execute(query.Expression).ReturnValue IEnumerable<Product> results = executeResult.ReturnValue as IEnumerable<Product>; // Processes the results. foreach (Product product in results) { Console.WriteLine("{0}, {1}", product.ProductID, product.ProductName); } } This may be not straight forward enough. So here a solution will implement fluent reflection with a ToDynamic() extension method: IEnumerable<Product> results = database.ToDynamic() // Starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue; C# 4.0 dynamic In this kind of scenarios, it is easy to have dynamic in mind, which enables developer to write whatever code after a dot: using (NorthwindDataContext database = new NorthwindDataContext()) { // Constructs the query. IQueryable<Product> query = database.Products.Where(product => product.ProductID > 0) .OrderBy(product => product.ProductName) .Take(2); // database.Provider dynamic dynamicDatabase = database; dynamic results = dynamicDatabase.Provider.Execute(query).ReturnValue; } This throws a RuntimeBinderException at runtime: 'System.Data.Linq.DataContext.Provider' is inaccessible due to its protection level. Here dynamic is able find the specified member. So the next thing is just writing some custom code to access the found member. .NET 4.0 DynamicObject, and DynamicWrapper<T> Where to put the custom code for dynamic? The answer is DynamicObject’s derived class. I first heard of DynamicObject from Anders Hejlsberg's video in PDC2008. It is very powerful, providing useful virtual methods to be overridden, like: TryGetMember() TrySetMember() TryInvokeMember() etc. (In 2008 they are called GetMember, SetMember, etc., with different signature.) For example, if dynamicDatabase is a DynamicObject, then the following code: dynamicDatabase.Provider will invoke dynamicDatabase.TryGetMember() to do the actual work, where custom code can be put into. Now create a type to inherit DynamicObject: public class DynamicWrapper<T> : DynamicObject { private readonly bool _isValueType; private readonly Type _type; private T _value; // Not readonly, for value type scenarios. public DynamicWrapper(ref T value) // Uses ref in case of value type. { if (value == null) { throw new ArgumentNullException("value"); } this._value = value; this._type = value.GetType(); this._isValueType = this._type.IsValueType; } public override bool TryGetMember(GetMemberBinder binder, out object result) { // Searches in current type's public and non-public properties. PropertyInfo property = this._type.GetTypeProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in explicitly implemented properties for interface. MethodInfo method = this._type.GetInterfaceMethod(string.Concat("get_", binder.Name), null); if (method != null) { result = method.Invoke(this._value, null).ToDynamic(); return true; } // Searches in current type's public and non-public fields. FieldInfo field = this._type.GetTypeField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // Searches in base type's public and non-public properties. property = this._type.GetBaseProperty(binder.Name); if (property != null) { result = property.GetValue(this._value, null).ToDynamic(); return true; } // Searches in base type's public and non-public fields. field = this._type.GetBaseField(binder.Name); if (field != null) { result = field.GetValue(this._value).ToDynamic(); return true; } // The specified member is not found. result = null; return false; } // Other overridden methods are not listed. } In the above code, GetTypeProperty(), GetInterfaceMethod(), GetTypeField(), GetBaseProperty(), and GetBaseField() are extension methods for Type class. For example: internal static class TypeExtensions { internal static FieldInfo GetBaseField(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeField(name) ?? @base.GetBaseField(name); } internal static PropertyInfo GetBaseProperty(this Type type, string name) { Type @base = type.BaseType; if (@base == null) { return null; } return @base.GetTypeProperty(name) ?? @base.GetBaseProperty(name); } internal static MethodInfo GetInterfaceMethod(this Type type, string name, params object[] args) { return type.GetInterfaces().Select(type.GetInterfaceMap).SelectMany(mapping => mapping.TargetMethods) .FirstOrDefault( method => method.Name.Split('.').Last().Equals(name, StringComparison.Ordinal) && method.GetParameters().Count() == args.Length && method.GetParameters().Select( (parameter, index) => parameter.ParameterType.IsAssignableFrom(args[index].GetType())).Aggregate( true, (a, b) => a && b)); } internal static FieldInfo GetTypeField(this Type type, string name) { return type.GetFields( BindingFlags.GetField | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( field => field.Name.Equals(name, StringComparison.Ordinal)); } internal static PropertyInfo GetTypeProperty(this Type type, string name) { return type.GetProperties( BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic).FirstOrDefault( property => property.Name.Equals(name, StringComparison.Ordinal)); } // Other extension methods are not listed. } So now, when invoked, TryGetMember() searches the specified member and invoke it. The code can be written like this: dynamic dynamicDatabase = new DynamicWrapper<NorthwindDataContext>(ref database); dynamic dynamicReturnValue = dynamicDatabase.Provider.Execute(query.Expression).ReturnValue; This greatly simplified reflection. ToDynamic() and fluent reflection To make it even more straight forward, A ToDynamic() method is provided: public static class DynamicWrapperExtensions { public static dynamic ToDynamic<T>(this T value) { return new DynamicWrapper<T>(ref value); } } and a ToStatic() method is provided to unwrap the value: public class DynamicWrapper<T> : DynamicObject { public T ToStatic() { return this._value; } } In the above TryGetMember() method, please notice it does not output the member’s value, but output a wrapped member value (that is, memberValue.ToDynamic()). This is very important to make the reflection fluent. Now the code becomes: IEnumerable<Product> results = database.ToDynamic() // Here starts fluent reflection. .Provider.Execute(query.Expression).ReturnValue .ToStatic(); // Unwraps to get the static value. With the help of TryConvert(): public class DynamicWrapper<T> : DynamicObject { public override bool TryConvert(ConvertBinder binder, out object result) { result = this._value; return true; } } ToStatic() can be omitted: IEnumerable<Product> results = database.ToDynamic() .Provider.Execute(query.Expression).ReturnValue; // Automatically converts to expected static value. Take a look at the reflection code at the beginning of this post again. Now it is much much simplified! Special scenarios In 90% of the scenarios ToDynamic() is enough. But there are some special scenarios. Access static members Using extension method ToDynamic() for accessing static members does not make sense. Instead, DynamicWrapper<T> has a parameterless constructor to handle these scenarios: public class DynamicWrapper<T> : DynamicObject { public DynamicWrapper() // For static. { this._type = typeof(T); this._isValueType = this._type.IsValueType; } } The reflection code should be like this: dynamic wrapper = new DynamicWrapper<StaticClass>(); int value = wrapper._value; int result = wrapper.PrivateMethod(); So accessing static member is also simple, and fluent of course. Change instances of value types Value type is much more complex. The main problem is, value type is copied when passing to a method as a parameter. This is why ref keyword is used for the constructor. That is, if a value type instance is passed to DynamicWrapper<T>, the instance itself will be stored in this._value of DynamicWrapper<T>. Without the ref keyword, when this._value is changed, the value type instance itself does not change. Consider FieldInfo.SetValue(). In the value type scenarios, invoking FieldInfo.SetValue(this._value, value) does not change this._value, because it changes the copy of this._value. I searched the Web and found a solution for setting the value of field: internal static class FieldInfoExtensions { internal static void SetValue<T>(this FieldInfo field, ref T obj, object value) { if (typeof(T).IsValueType) { field.SetValueDirect(__makeref(obj), value); // For value type. } else { field.SetValue(obj, value); // For reference type. } } } Here __makeref is a undocumented keyword of C#. But method invocation has problem. This is the source code of TryInvokeMember(): public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) { if (binder == null) { throw new ArgumentNullException("binder"); } MethodInfo method = this._type.GetTypeMethod(binder.Name, args) ?? this._type.GetInterfaceMethod(binder.Name, args) ?? this._type.GetBaseMethod(binder.Name, args); if (method != null) { // Oops! // If the returnValue is a struct, it is copied to heap. object resultValue = method.Invoke(this._value, args); // And result is a wrapper of that copied struct. result = new DynamicWrapper<object>(ref resultValue); return true; } result = null; return false; } If the returned value is of value type, it will definitely copied, because MethodInfo.Invoke() does return object. If changing the value of the result, the copied struct is changed instead of the original struct. And so is the property and index accessing. They are both actually method invocation. For less confusion, setting property and index are not allowed on struct. Conclusions The DynamicWrapper<T> provides a simplified solution for reflection programming. It works for normal classes (reference types), accessing both instance and static members. In most of the scenarios, just remember to invoke ToDynamic() method, and access whatever you want: StaticType result = someValue.ToDynamic()._field.Method().Property[index]; In some special scenarios which requires changing the value of a struct (value type), this DynamicWrapper<T> does not work perfectly. Only changing struct’s field value is supported. The source code can be downloaded from here, including a few unit test code.

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C#/.NET Little Wonders: Interlocked CompareExchange()

- by James Michael Hare

Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner. Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references). This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values. But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically. If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue! Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that. But what if we want to work with doubles, for example? Let’s say we wanted to add the numbers from 0 to 99,999 in parallel. We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2: 3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999). But when we run this in parallel as written above, we’ll likely get something far off. The result of one of my runs, for example, was 1,281,880,740. That is way off! If this were banking software we’d be in big trouble with our clients. So what happened? The += operator is not atomic, it will read in the current value, add the result, then store it back into the total. At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add. So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3: 4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000. One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently. In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution! So, if lock is sufficient for most needs, why would we ever consider another solution? The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free. Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead. This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path. If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above. The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged. Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references. It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly). Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us? Well, we can grab the current total, and exchange the new value if total hasn’t changed. This would look like this: 1: // grab the snapshot 2: double current = total; 3: 4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg). This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same? Well, we know that in either case we will get the previous value of total (before the exchange), back as a result. Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail? That’s up to you and the problem you are trying to solve. It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again. Let’s try that: 1: double current = total; 2: 3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8: 9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16: This is not trivial code, but it illustrates a possible use of CompareExchange(). What we are doing is first checking to see if we succeed on the first try, and if so great! If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds. You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations. Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock. For example, you could use it to create a simple lazy instantiation implementation. In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4: 5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15: 16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance. If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used. In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance. Another possible use would be in concurrent collections. Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”. We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise! So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5: 6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4: 5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8: 9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12: 13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21: 22: // ... 23: } Notice a similar paradigm here as with adding our doubles before. What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head. This will create our stack behavior (LIFO – Last In, First Out). Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode. This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock! If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention. If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity. Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment. In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code. As such, the standard lock is often sufficient for most thread-safety needs. But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

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