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ASP.NET PDF Viewer using C#, VB/NETDuck-typed programming is about writing code where the definition of the classes is not known ahead of time, but you know the object has some specific behavior. Reuse is made possible by cloning and assembling the objects dynamically at runtime. Classical object-oriented programming is about defining the behavior of the type before execution. The following source code is for an example Dynamic HTML (DHTML) and JavaScript application that illustrates the essence of duck-typed programming. Source: /website/ROOT/gettingstarted/PrototypeBased.html <html> <head> <title>Prototype-based Programming</title> <script language="JavaScript" type="text/javascript"> function Variation1() { document.getElementById( "output").innerHTML = "Ran Variation 1"; } function Variation2() { document.getElementById( "output").innerHTML = "Ran Variation 2"; } var obj = new Object(); function RunVariation() { obj.runIt(); } </script> </head> <body> <input type="button" value="Variation 1" onclick="obj.runIt = Variation1; RunVariation()" /> <input type="button" value="Variation 2" onclick="obj.runIt = Variation2; RunVariation()" /><br/> <div id="output">Nothing yet</div> </body> </html> In the example, the bold code segments illustrate the duck-typed programming constructs. When the Web browser loads the code, it will be parsed from top to bottom. When the code has been parsed, the following types and object instances will be active: Definition of the functions Variation1, Variation2, and RunVariation Instantiation and definition of the variable obj, which references a plain vanilla Object instance Definition of two buttons (Variation 1 and Variation 2) that execute some JavaScript when clicked Definition of an HTML div element that has the identifier output qr code generator using vb.net, devexpress barcode control winforms, winforms code 128, vb.net ean 128, vb.net generate ean 13, pdf417 vb.net, c# remove text from pdf, c# replace text in pdf, vb.net generate data matrix, c# remove text from pdf,Veteran Java ME developers will notice that many of the BlackBerry APIs, particularly those related to media and wireless messaging, are similar or identical to their Java ME counterparts. I point out the important differences within the text. These developers should particularly focus on 1 for setting up their BlackBerry environment and 9 to learn about the critical differences between Java ME and BlackBerry security. A directory is a logically grouped collection of objects with attributes organized in a hierarchical fashion. LDAP directories can track anything from users and groups to Finally, BlackBerry experts can largely skip 1, and refer to individual chapters to learn about particular topics of interest. Veterans will recognize the importance of BlackBerry device software versions, and will pay particular attention to the tables that show the significant differences between versions.Notes on Conventions One of my personal pet peeves is that most programming books today are written as if it was still 1990. Thanks to the ubiquitous availability of Javadocs, we can easily look up the details about individual methods. Thanks to modern IDEs, we can easily discover available APIs and find out how to use them properly. In writing this book, I ve focused on the things that you can t easily see in the Javadocs: the meaning behind methods, when to call particular APIs, and the tradeoffs between various solutions. To avoid distraction, I generally omit parameters when I name a method. I generally omit the package name when I name a class. In Eclipse, Ctrl+Space is your friend. Of course, in situations where usage is ambiguous, I provide the details explaining which item is being used. Similarly, exception handling is a great tool for writing robust software, but tends to muddy even the simplest examples. I generally omit exception handling when introducing a new method unless its exceptions are particularly unusual. The end of each chapter contains a longer set of sample code that runs as a stand-alone application. Here, I fully handle all exceptions, include full package names, and do everything else to show how a real-world application should perform. computers, printers, and mount points on servers. The LDAP implementation for Mac OS X Server is slapd. The slapd process uses a number of schema files, located in the directory /etc/openldap/schema, to define the structure of the directory services database. These schema files include the object classes and attributes that the LDAP server presents to LDAP clients. Attributes are the same as those located in property list files, as noted earlier in this chapter. An ObjectClass is a set of attributes. New schema files can be added, thus extending the functionality of LDAP and therefore Open Directory. Schema files can also be augmented to include new attributes. When you enhance the metadata stored for objects in LDAP, it is therefore typically referred to as extending the schema. Calling the function RunVariation generates an exception, because obj is a plain vanilla object instance and has no method implementation for runIt A classical programming language such as Java, C#, or C++ is not able to compile the JavaScript code, because the function RunVariation executes a method on a type that is not defined to possess the method When an object method is called, as in the source code, it is called latent typing Latent typing is the identification of the type associated with a variable during the runtime of the application In the case of the source code example, that means the exact behavior of obj is not known until the application is executed Hence, RunVariation may or may not work In the example code, when the input buttons are pressed, the property objrunIt is assigned to either Variation1 or Variation2.
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