barcode generator vb.net source code PREPARING TO PACKAGE in Java

Implement Data Matrix ECC200 in Java PREPARING TO PACKAGE

Comments The unary plus operator. You can already use this operator with numbers, as in +5. But if you enter this value in Visual Studio, the plus operator gets stripped out since it is considered redundant. However, if you overload this operator on a class of your own, Visual Studio will retain the unary form of this operator when used in code.

Tracing provides you with a snapshot of the steps your code has taken after the code has run. At times, however, you d like to monitor your code while it is running. What you want is more of a CAT scan than an autopsy. The code equivalent of a CAT scan is a symbolic debugger. When you run your code in the debugger, you can watch your code work, step by step. As you walk through the code, you can see the variables change values, and you can watch as objects are created and destroyed. This section will provide a brief introduction to the most important parts of the debugger that accompanies the VS/VWD IDE. For complete coverage of how to use the debugger, we urge you to spend time with the documentation and to experiment freely. The debugger is one of the most powerful tools at your disposal for learning ASP.NET. An application can be configured to either enable or disable debugging. This is done through the configuration file, web.config. As you ve already seen many times, the first time you run a new application, a dialog box will pop up, offering to automatically make the necessary edits to web.config to enable debugging.

Summary

is due to arrive at 8:30 p.m. DateTime lives in this same slightly fuzzy world, where 9:00 a.m. is, in some sense, the same time before and after daylight saving comes into effect. So if you have a DateTimeOffset that you wish to display, unless you want to show the time zone information in the user interface, you will most likely convert it to a DateTime that s relative to the local time zone, as Example 10-32 shows.

int[] dollars = null; String dbName = "QuoteData"; int dbType = 0x494E5653; //'INVS' //'CATT' Palm-registered database creator id //for Catapult Technologies. Assigned hex value int dbCreator = 0x43415454; com.sun.kjava.Database quoteDB = new Database (dbType, dbCreator, Database.READWRITE); if (!quoteDB.isOpen()) { Database.create(0, dbName, dbCreator, dbType, false); quoteDB = new Database (dbType, dbCreator, Database.READWRITE); } boolean found = false; for (int i = 0; i<quoteDB.getNumberOfRecords(); i++) { String raw = new String(quoteDB.getRecord(i)); if (raw.startsWith(symbol + ';')) { found = true; byte[] rec = quoteDB.getRecord(i); dollars = parsePrices(rec); break; } } if (!found) { dollars = null; } quoteDB.close(); return dollars; } private void displayChart(String currentSymbol) { int[] prices = retrievePrices(currentSymbol); if (prices != null) { if (prices.length > 2) { paintChart(currentSymbol,prices[0],prices[2]); } else { Graphics.drawRectangle(5,60,155,70,Graphics.ERASE,0); Graphics.drawString("Recorded price for " + currentSymbol + " is: $" + prices[0] + "." + prices[1], 5, 65, Graphics.PLAIN); Graphics.drawString("No historical data exists.", 5, 80, Graphics.INVERT); } } else { Graphics.playSound(Graphics.SOUND_ERROR); Dialog noDataAlert = new Dialog(this,"Alert", "No price exists for " + currentSymbol,"OK"); noDataAlert.showDialog(); } }

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Having now covered some of the basic scenarios you d want to write unit tests for, let s go ahead and actually write a few tests. In this section, you ll write a simple test that verifies that Events persist correctly, along with a few of their fields.

Explanation Overloaded; creates an instance of Regex Property that returns the options passed in to the constructor Method that indicates whether a match is found in the input string Searches an input string and returns a match for a regular expression Searches an input string and returns all successful matches for a regular expression Replaces all occurrences of a pattern with a replacement string Splits an input string into an array of substrings based on a regular expression

All the code we add in this chapter will appear between these two lines. Remember, modules are a lot like classes and structures, but you can t create instances of them; all their members are shared with all parts of your source code. This allows them to be used anywhere in the application. We don t need to do anything special to make them available to the entire program, other than to set the access level of each member as needed. First, we ll add some general constants used throughout the program. Back in Visual Basic 6.0, I would have called these global constants. But now they are simply shared members of the General module. Add the following code just below the Module General statement.

Delegates Delegates define arguments and return values for a method, and encase them in a single object all their own. They are generally used to support the event process, callback procedures, and indirect calls to class methods.

A group of interconnected computers is a network. Over time, networking has grown from something that was available only to governments and large organizations to the almost ubiquitous and truly amazing internet. Though the concept is simple allow computers to communicate networking does involve advanced technology. We won t get into great detail here, but we ll cover the core tenets as a background to the general networking you ll do in the remainder of this chapter.

Although all the settings are as close as typing My.Settings.something in the code, some settings may initially be undefined, and using them could involve a lot of repetitive code that checks for valid settings. To reduce overall code and CPU cycles, we will cache some of the settings for easy use throughout the application. Let s add three more global variables to cache some of the settings. Open the General.vb module, and add these three new class members.

Now if we rerun the same compile, preverify, JAR, and execution steps, the alert not only displays the price quote, but also the advertisement inside of the ticker at the top of the display, as shown in figure 5.19. Drawing, using Canvas We are now ready to develop the third and final user interface display in the MIDP version of the tutorial application. Given an investment, like a stock or mutual fund, we want to provide the customers with a picture of how the investment is doing on the market. Remember, users of MIDP devices may not be able to give their full attention to the device. Therefore, we want to give them a picture of how the stock has done recently. Per the requirements, the application tracks the last two prices (current and historical) for each investment requested by the user. If a quote for an investment has been retrieved before, we want to provide a bar graph depicting the current and previous prices in relationship to each other (see figure 3.4 in chapter 3). To do this, we draw geometric shapes directly to the screen. This is done using the low-level graphical user interface API. The only Displayable class available to encapsulate graphical elements in the low-level API is Canvas. Unlike the Displayable class counterparts (Form, Alert, List, or TextBox) in the high-level API, the Canvas class is abstract requiring the developer to create his or her own concrete Canvas subclass. We name our Canvas subclass ChartCanvas and put it in its own ChartCanvas.java file. The Canvas class has one abstract method, paint(Graphics), which requires implementation.