generate qr code asp.net mvc WRITING ALGORITHMS in VB.NET

Making QR Code ISO/IEC18004 in VB.NET WRITING ALGORITHMS

CHAPTER 6 WRITING ALGORITHMS
Paint Denso QR Bar Code In Visual Basic .NET
Using Barcode encoder for .NET Control to generate, create QR Code image in VS .NET applications.
www.OnBarcode.com
QR Code JIS X 0510 Recognizer In Visual Basic .NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Enhancing Types Using Functors
PDF417 Encoder In Visual Basic .NET
Using Barcode creation for VS .NET Control to generate, create PDF 417 image in .NET framework applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Maker In VB.NET
Using Barcode creator for .NET Control to generate, create QR Code image in .NET applications.
www.OnBarcode.com
The Proxy pattern is useful when you want to modify the functionality of a type without the blessing or cooperation of that type. SynchronizedList<> illustrates how synchronization capabilities can be added without having to change the type. In contrast, the various interface implementations of the Decorator pattern cooperate to solve a problem. Enhancing types through the Proxy pattern can be very useful. The previous example illustrated synchronization, but in the developer community the Proxy pattern is implemented in conjunction with functors.2 The purpose of a functor is to perform a mapping from one domain to another or to perform an operation or function. Functors are traditionally mathematically based, but need not be. You want to use functors because they make it possible to attach standard logic to another type using a predefined construct. For example, when used by collections, Generics validate the type, but do not validate whether the contents of the type are correct. You use a predicate functor to validate the contents of the type. The most common functor types are defined as follows: Comparer: Accepts two objects and performs a comparison between the two. The return value is an integer, which represents whether one object is equal, less than, or greater than the other. Closure: Accepts a single object and performs some logic. No value is returned. Predicate: Accepts a single value and performs some logic. A true value indicates that the predicate logic triggered, and a false value means that the predicate logic didn t trigger. Transformer: Accepts a single value and performs a transformation that results in either a new type being generated or the original type being transformed. Let s take a closer look at these common functor types.
EAN13 Generator In Visual Basic .NET
Using Barcode creator for .NET Control to generate, create EAN / UCC - 13 image in VS .NET applications.
www.OnBarcode.com
Code 3/9 Generator In VB.NET
Using Barcode printer for Visual Studio .NET Control to generate, create Code 39 Extended image in .NET framework applications.
www.OnBarcode.com
Adding Comparer Capabilities
Encode 1D In VB.NET
Using Barcode maker for Visual Studio .NET Control to generate, create 1D image in .NET framework applications.
www.OnBarcode.com
Print Leitcode In Visual Basic .NET
Using Barcode creation for Visual Studio .NET Control to generate, create Leitcode image in .NET applications.
www.OnBarcode.com
The IComparable interface, shown in the following example, is defined in the .NET base classes: public interface IComparable { int CompareTo(object obj); } The IComparable interface has a single method, CompareTo, that represents the object instance to compare to. The IComparable interface works if the object that performs the testing implements this interface. The problem with this approach is if the objects to be compared don t have IComparable implemented, then the comparer functor won t work. It s similar to the Decorator pattern, where all implementations concerned have to cooperate. From the .NET base classes, another interface, IComparer, can be used to compare two objects and is defined as follows:
QR Code Encoder In Objective-C
Using Barcode maker for iPhone Control to generate, create QR Code image in iPhone applications.
www.OnBarcode.com
QR Code ISO/IEC18004 Maker In None
Using Barcode generation for Excel Control to generate, create QR-Code image in Office Excel applications.
www.OnBarcode.com
2. http://en.wikipedia.org/wiki/Functor, http://dictionary.reference.com/search q=functor
Encoding GS1 DataBar-14 In Visual Studio .NET
Using Barcode printer for .NET Control to generate, create GS1 RSS image in .NET applications.
www.OnBarcode.com
Data Matrix Generation In VS .NET
Using Barcode creation for ASP.NET Control to generate, create Data Matrix ECC200 image in ASP.NET applications.
www.OnBarcode.com
CHAPTER 6 WRITING ALGORITHMS
Print Code 3/9 In Java
Using Barcode creator for Java Control to generate, create Code-39 image in Java applications.
www.OnBarcode.com
Read QR Code JIS X 0510 In Visual Basic .NET
Using Barcode decoder for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
public interface IComparer { int Compare(object x, object y); } IComparer has a single method with two parameters representing the objects to be compared. The advantage of the IComparer interface is that the objects to be tested don t have to implement any additional functionality. For the scope of this pattern, and the rest of this book, examples will include a delegate, not an interface. The advantage of a delegate is that it can be implemented using C# 2.0 anonymous methods or any method of a class, whereas an interface must be implemented and then instantiated. If necessary, you can apply the Adapter pattern (which I discussed in 5) to convert the delegate into an interface. The IComparer interface defined in terms of a delegate is as follows: public delegate int DelegateComparer< type1, type2>( type1 obj1, type2 obj2); The delegate DelegateComparer<> is defined using a template, making it type safe, and returns an int value indicating the results of a comparison. The two parameters are the object instances to compare. To give you a clearer idea of how the comparer delegate works, let s see how to create a program that generates a flight ticket.
UPC A Decoder In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Encode EAN-13 Supplement 5 In Visual Studio .NET
Using Barcode printer for Visual Studio .NET Control to generate, create GS1 - 13 image in .NET framework applications.
www.OnBarcode.com
Creating a Flight Ticket Application
QR Code 2d Barcode Generator In Java
Using Barcode generator for Android Control to generate, create QR Code JIS X 0510 image in Android applications.
www.OnBarcode.com
Printing GS1 DataBar-14 In Java
Using Barcode printer for Java Control to generate, create GS1 DataBar image in Java applications.
www.OnBarcode.com
For this flight ticket example, assume a flight ticket is defined in terms of individual flight legs. Consider the following interface definition used to define one leg of a flight: interface IFlight { string Origin { get; set; } string Destination { get; set;} IFlight NextLeg { get; set; } } The interface IFlight has three properties: two strings and a reference to IFlight. The individual flight legs can be managed either using an individual instance that references another instance or as a collection of flight legs. The property NextLeg represents a leg in a flight, and therefore no collection is required. The interface IFlight has been reduced to the essentials to illustrate how you employ a comparer functor. The comparer functor is used by the property NextLeg to ensure that the property isn t assigned the same leg twice, as it would be very silly to fly to the same destination at the same time. You may think that it s better to have a collection of flight legs rather than one flight leg referencing another flight leg, but this depends on the nature of the application. And in this case, I m trying to illustrate that the delegate DelegateComparer<> can also be applied in contexts where there is no collection. Now that you are aware of functors, you may realize that most of the time other documentation or other books will illustrate them solely in the context of a collection. This isn t, and shouldn t be, the only way to use functors. Functors are little black boxes that carry out a specific piece of logic. Remember from previous chapters that you want little black boxes throughout your entire code.
PDF-417 2d Barcode Scanner In .NET Framework
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Drawing Code 128 Code Set B In None
Using Barcode creation for Online Control to generate, create Code 128B image in Online applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.