qr code c# MEASURING FOR ROBUST PERFORMANCE in .net C#

Printing qr-codes in .net C# MEASURING FOR ROBUST PERFORMANCE

// perform some calculations int sumResult = calc.CalculateProduct(10, 20); int productResult = calc.CalculateSum(10, 20); int subtractionResult = calc.CalculateSubtraction(10, 20); int divisionResult = calc.CalculateDivision(10, 20); // write out the results Console.WriteLine("Sum Result: {0}", sumResult); Console.WriteLine("Product Result: {0}", productResult); Console.WriteLine("Subtraction Result: {0}", subtractionResult); Console.WriteLine("Division Result: {0}", divisionResult); // wait for input before exiting Console.WriteLine("Press enter to finish"); Console.ReadLine(); } } Compiling and running the test class and the Calculator class gives us the following results: Sum Result: 200 Product Result: 30 Subtraction Result: -10 Division Result: 0 Press enter to finish It all looks good, but as we ll see, I have created some implied rules that you need to know in order to use my class without causing an exception or getting odd behavior. The first implied rule is that the second parameter to the CalculateDivision method can t be zero. See what happens if we add the following statement to the CalculatorTest class:

The interface ITestFlyweight has a single property, Identifier, that retrieves a property value. In your own solutions, the interface could have as many methods or properties as needed, but the interface needs to be immutable. Additionally, an interface doesn t need to be used; instead you could employ a base class. Or if desired, in the declaration of FlyweightFactory you can include the type object, which allows the referencing of any object instance. In the example, TestFlyweightA and TestFlyweightB both implement the ITestFlyweight interface and a rudimentary implementation of the property Identifier. The following Builder class illustrates a complete Flyweight pattern implementation: class FlyweightBuilder { public static ITestFlyweight Transformation( object desc) { if( String.Compare( (string)desc, "TestFlyweightA") == 0) { return new TestFlyweightA(); } else if( String.Compare( (string)desc, "TestFlyweightB") == 0) { return new TestFlyweightB(); } throw new NotSupportedException(); } public static IFlyweightCollection< ITestFlyweight, string> Instantiate() { return new FlyweightCollection< ITestFlyweight, string>( new DelegateTransformer< string, ITestFlyweight>( FlyweightBuilder.Transformation)); } } FlyweightBuilder has two static methods: Instantiate and Transformation. The method Instantiate instantiates the FlyweightCollection class, where the Generic parameter is defined to be ITestFlyweight. This means that this Flyweight pattern implementation creates objects of type ITestFlyweight. The method Transformation instantiates either TestFlyweightA or TestFlyweightB depending on the value of parameter desc. If desc doesn t resolve to one of the two values, an exception is thrown.

Finalizers perform actions required to clean up or release unmanaged resources before an instance of a class is destroyed. The important things to know about finalizers are the following: You can only have a single finalizer per class. A finalizer cannot have parameters. A finalizer cannot have accessibility modifiers. A finalizer has the same name as the class, but is preceded by a tilde character (pronounced TIL-duh). A finalizer only acts on instances of classes. Hence, there are no static finalizers. A finalizer cannot be called explicitly by your code. It is called in the garbage collection process, when your class is no longer accessible. For example, the following code illustrates the syntax for a finalizer of a class called Class1: Class1 { ~Class1() { CleanupCode } ... } Some important guidelines for using finalizers are the following: Don t implement a finalizer if you don t need one. They can incur performance costs. A finalizer should only release external resources that the object owns. It should not access other objects. Since it cannot be called explicitly, make it less visible by not declaring it with public access.

Expression/Abstract Syntax Trees (AST)

Another interesting aspect of the Membership type is that if you choose to make use of any of the new ASP .NET 2.0 Login controls (Login, LoginView, LoginStatus, LoginName, and PasswordRecovery), authentication can be achieved code-free, as these new server-side controls manipulate the Membership type behind the scenes. You ll get to know the role of these new controls in just a bit. However for now let s see how to make use of the Membership type directly.

Another facet of the new XML-related APIs in Java 6 has to do with JSR 173 and the Streaming API for XML, or StAX. It is like SAX parsing, but works on pulling events from the parser, instead of the parser throwing events at you. It definitely does not follow the tree model of DOM, but does allow you to pause the parsing and skip ahead if necessary; and unlike SAX, it does allow writing of XML documents, not just reading. There are two parts to the StAX API: a Cursor API for walking the document from beginning to end, and an Iterator API for handling events in the order that they appear in the source document. You ll see how to use both, but first you need an XML document to read. Listing 6-15 shows one that represents a series of points, with x and y coordinates for each.

Note This commit-time optimization in PL/SQL may be suspended when you are performing distributed

In 14, you saw that you can use a foreach statement to cycle through the elements of an array. In this chapter, you ll take a closer look at arrays and see why they can be processed by foreach statements. You ll also look at how you can add this capability to your own userdefined classes. Later in the chapter, I ll discuss the use of iterators.