c# create and print barcode Interpreter Pattern in Visual C#.NET

Painting Code 3/9 in Visual C#.NET Interpreter Pattern

Interpreter Pattern
Code 39 Printer In Visual C#.NET
Using Barcode creation for VS .NET Control to generate, create USS Code 39 image in .NET applications.
www.OnBarcode.com
ANSI/AIM Code 39 Recognizer In Visual C#.NET
Using Barcode reader for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
The Interpreter pattern supports the interpretation of instructions written in a language or notation defined for a specific purpose. The notation is precise and can be defined in terms of a grammar.
UPC-A Supplement 5 Creation In C#
Using Barcode creation for .NET Control to generate, create GTIN - 12 image in .NET framework applications.
www.OnBarcode.com
Creating EAN128 In C#
Using Barcode maker for .NET framework Control to generate, create EAN 128 image in Visual Studio .NET applications.
www.OnBarcode.com
* Thanks to Nigel Horspool for suggesting and executing these tests.
Drawing DataMatrix In Visual C#
Using Barcode generator for VS .NET Control to generate, create Data Matrix image in .NET applications.
www.OnBarcode.com
Creating Code 128 Code Set C In Visual C#.NET
Using Barcode maker for .NET framework Control to generate, create Code 128C image in Visual Studio .NET applications.
www.OnBarcode.com
Interpreter Pattern |
Make Barcode In C#.NET
Using Barcode generation for VS .NET Control to generate, create Barcode image in .NET framework applications.
www.OnBarcode.com
Painting Leitcode In C#.NET
Using Barcode drawer for .NET framework Control to generate, create Leitcode image in .NET applications.
www.OnBarcode.com
Illustration
Code 39 Extended Creation In Java
Using Barcode creation for BIRT Control to generate, create Code 39 Full ASCII image in BIRT reports applications.
www.OnBarcode.com
Make Code 3 Of 9 In Java
Using Barcode printer for Android Control to generate, create Code 39 image in Android applications.
www.OnBarcode.com
XML (eXtended Markup Language) is a very popular way of expressing the format of data. XML consists of tags that introduce attributes and associated values in a simple nested and sequential notation. Consider the example in Figure 10-4 (a) shows an XML description of a GUI depicted in (b). The XML corresponds to the controls and parameters of a Windows form. Thus, the following:
QR Printer In Java
Using Barcode maker for Android Control to generate, create QR Code image in Android applications.
www.OnBarcode.com
Barcode Printer In None
Using Barcode encoder for Software Control to generate, create Barcode image in Software applications.
www.OnBarcode.com
<TextBox Top="10" Left="100" Name="eurobox" />
PDF 417 Maker In None
Using Barcode generator for Software Control to generate, create PDF 417 image in Software applications.
www.OnBarcode.com
Barcode Drawer In Objective-C
Using Barcode maker for iPad Control to generate, create Barcode image in iPad applications.
www.OnBarcode.com
specifies a TextBox control followed by pixel values for its top-left corner and the name by which it will be known in the program ("eurobox"). The corresponding label at top=10 pixels has the text Paid on hols so that will be opposite the eurobox control when it is laid out on the form.
Barcode Drawer In Java
Using Barcode encoder for BIRT reports Control to generate, create Barcode image in BIRT applications.
www.OnBarcode.com
Drawing EAN / UCC - 13 In Visual Studio .NET
Using Barcode drawer for VS .NET Control to generate, create EAN13 image in VS .NET applications.
www.OnBarcode.com
The XML specification is read into a program, checked, and interpreted into GUI objects to be displayed on the screen. Thus, this example illustrates the essence of the Interpreter pattern.
Code 39 Full ASCII Generator In None
Using Barcode maker for Font Control to generate, create Code 39 Full ASCII image in Font applications.
www.OnBarcode.com
Generating Barcode In None
Using Barcode generation for Online Control to generate, create Barcode image in Online applications.
www.OnBarcode.com
Grammars
2D Barcode Encoder In Visual Basic .NET
Using Barcode encoder for .NET Control to generate, create Matrix image in .NET applications.
www.OnBarcode.com
Barcode Drawer In Java
Using Barcode drawer for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Languages can be expressed in other notations as well. A familiar form is a grammar of terms. Terms written in sequence must follow each other; alternatives are indicated with a | and repetition by recursive definitions. Given this scheme, we could specify a grammar for the course rules laid out earlier in Example 10-2 as:
|
10: Behavioral Patterns: Visitor, Interpreter, and Memento
1 2 3 4 5 6 7 8 9 10 11
course restcourse nonterminalpart terminalpart restterminalpart group lab text midterm exam weight
= = = = = = = = = = =
name restcourse terminalpart | nonterminalpart | restcourse | empty group ( terminalpart restterminalpart ) lab | test | group terminalpart restterminalpart | empty midterm | exam L weight T weight M weight E weight integer
empty is a special term that matches nothing and returns the interpreter to the previous term. L, T, M, E, and integer have their literal meanings.
This grammar is workable for interpreting course rules, although it has one deficiency: both terminalpart and nonterminalpart can start with a group (midterm or exam), and therefore the grammar is ambiguous in the first term as the input is being processed. However, the ambiguity can be resolved by looking ahead to the next few terms. Ambiguous grammars can also be transformed into unambiguous grammars by introducing more terms.
Design
As seen in both the course rules (grammar) and the XML for the GUI (Figure 10-4), there is a distinction between terminals and nonterminals in the input to the interpreter. In the grammar, terminals are final terms, whereas nonterminals comprise other terms. The Interpreter is an operation defined at all levels to process input as required. The operations are done in the context of some input and output. The UML diagram for this pattern is given in Figure 10-5.
Context
Client <<use>>
<<interface>> Term +Interpreter( )
Terminal +Interpreter( )
Nonterminal +Interpreter( )
Interpreter Pattern |
The players in the pattern are:
Client
A class that builds an object structure that represents a set of instructions in the given grammar
Context
A class that contains information for use by the Interpreter (usually its input and output)
Term
An abstract class that provides an interface for all the classes in the structure and a default for the Interpreter operation
Nonterminal
A class that implements the Interpreter and also can contain other Term instances
Terminal
A class that implements the Interpreter
QUIZ
Match the Interpreter Pattern Players with the XML Illustration
To test whether you understand the Interpreter pattern, cover the lefthand column of the table below and see if you can identify its players among the items from the illustrative example (Figure 10-4), as shown in the righthand column. Then check your answers against the lefthand column.
Context Terminal Nontermial Interpreter
Rule specification and the GUI output An attribute (e.g., Top) A tag (e.g., TextBox) Process of transforming the XML to the GUI
Parsing
The Interpreter pattern does not specify how the object structure is created. This process is known as parsing and involves matching input against a grammar to create a structure, often known as a parse tree. Once the structure is created, the Interpreter starts its work and will match a new set of input against the parsed grammar. For example, the XML in Figure 10-4(a) results in a set of controls that are drawn on the screen. The user can then type in input and press buttons, and these actions are interpreted according to the type of boxes and buttons that were parsed. The process is shown in Figure 10-6.
|
Copyright © OnBarcode.com . All rights reserved.