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One of the Most Powerful Debugging Practices


The hard to find bugs generally occur under circumstances that are relatively rare. After all, if the program re-boots your system every time you run it, you will usually fix that error. Some of these rare cases are caused by executing a code path that has never been executed before. When your program first starts, you will generally create a number of objects. You have a code path you take if those constructors throw exceptions, but have they ever failed?

If not, you have an accident waiting to happen. What does your program actually do when that particular constructor fails? As long as you have not tested a code path, you have not fully tested your program. Be sure that you exercise every code path. If you have an "if () ... else ..." and you have always executed the "else" part, then the "if" part is a bug waiting to happen.

There is a very simple way to handle this, and do so in a manner that will help you as you first run your code. The beauty of using traps is it helps you immediately, so that you will quickly find that you automatically put them in as you write code.

This is composed of two methods, trap() and trap(bool) – I have included Java, C++, & assembler examples at the, but for illustration I will use C# here. What a trap does is drop you into the debugger when you hit one. First the example, then why this is so useful

// Open an XML file
XmlReader reader;
if (string.IsNullOrEmpty(username)) {
   reader = XmlReader.Create(filename, xmlSettings);
} else {
   XmlUrlResolver resolver = new XmlZipResolver();
   resolver.Credentials = hasDomain ? new NetworkCredential(user, password, domain) : new NetworkCredential(user, password);
   xmlSettings.XmlResolver = resolver;
   reader = XmlReader.Create(filename, xmlSettings);

The Immediate Pay-Off

Why is this a big help from the start? Because it helps you single step through each part of your code once. In the code above you probably test at first with no username so you'll fall in the debugger on the first trap. You mark it and then step over the Create. You may single step a couple of lines after to make sure the xml is good, then you go.

Note: The way I mark a trap I hit is to put ** at the start of that line. When I finish a debug session a simple compile will show me every place I added the **. Because I add the ** to the same line, line numbers stay the same and the debugger matches your source line correctly (if you delete the line with the trap when you hit it the debugger will be off by one line anywhere further down in that file).

Ok, so you've been working on this module for a couple of days, it's all working well and you decide to try an XML file that requires credentials. When you do the debugger will stop at the top of the else. You then step through the code opening the XML file with credentials. The beauty of this approach is you don't need to remember that you haven't walked through these 4 lines of code. You don't need to go find those 4 lines of code. It just drops you there in the debugger. I think this is one of the most powerful debugging tools I use because I now easily single step through every line of my code – and find enough issues from this practice to make it well worth it.

The Secondary Pay-Off

This practice also provides a second great pay-off. All the traps removed initially are either very common code paths or paths specifically hit due to unit testing. So when you are "done" with a module and all your tests are written, any remaining traps are indicators of tests that remain to be written. You now have a very easy way to identify remaining unit tests that need to be written.

And the traps are implemented so they only run on a debug build. So you can ship code with traps in it (we shouldn't, but we all do) and it will have no impact on the release version.


C# & Java - Download Trap.zip

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Tags Start & End

Tags Can Start & End Anywhere

Appendix B

.NET code for multi-page image output

Appendix A

Java code for multi-page image output

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Time Zone Conversion

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Image Output Format

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PostScript Output Format

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Stored Procedure Wizard (Designer)

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Boolean Conditional Wizard (Designer)

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Reorganized Ribbon

The ribbon menus have been re-organized and consolidated to improve the report design workflow.

XPath 2.0 as Data Source

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SQL Select Debugger

SQL Select  Debugger

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Added Javelin into the RESTful Engine

Support for Google Application Engine Integration

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Additional Refinement for HTML Output

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Redesigned PDF Output Support

This new  integration will allow for processing of complex scripts and bi-directional  text such as Arabic.  Your PDF output  will be much tighter and more closely match your template, and we’ll be able  to respond rapidly to PDF requests and fixes.

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Includes support for new ForEach and slide break handling, table header row repeat across slide breaks, and native Microsoft support for charts and images.

Tags are Color Coded

Tags are color coded in the template by type, making it easy to visually identify them.

Increased Performance

Version 13’s core code has been reworked and optimized to offer a reduced memory footprint, faster PDF generation and full documentation of supported features and limitations in the specifications for DOCX, XLSX and PPTX.

Advanced Image Properties

Documents can include advanced Word image properties such as shadows, borders, and styles.

Improved HTML Output

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Version 13 New Data Sources

Windward now works with a slew of new datasources: MongoDB, JSON, Cassandra, OData, Salesforce.com

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The Generate Code tool in the designer allows you to open an existing template and, with a click of a button, automatically create a window with the code needed to run your current template with all data sources and variables. Simply copy this code and paste into your application's code in the appropriate place. You now have Windward integrated into your application.

You only need to do this once. You do not do this for each template. Instead, where it has explicit files for the template and output, change that to parameters you pass to this code. Same for the parameters passed to Windward. This example uses explicit values to show you what to substitute in where.

Pivot Tables Adjusted in Output

Any pivot tables in an XLSX template are carried over to the XLSX output. The ranges in the pivot ranges are adjusted to match the generated output. So your final XLSX will have pivot tables set as expected in the generated file.

This makes creating an XLSX workbook with pivot tables trivial.

Imported Template Can be Set to Match the Parent Styles

In an imported sub-template, if its properties for a style (ex. Normal) differ from the parent template's properties for the style, the use in the sub-template can be set to either use the properties in the sub-template, or the properties in the parent.

You set to retain when you don't want the child template's styling to change when imported. You set to use the parent when you want the styling of the imported template to match the styling in the parent.

Any explicit styling is always retained. This only impacts styling set by styles.

Tags can be Placed in Text Boxes

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HTML Output Supports Embedded Images

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Footnotes & Endnotes can Have Tags

You can place tags in pretty much any part of a template, including in footnotes & endnotes.

Document Locking Supported in DOCX & XLSX

Any parts of a DOCX or XLSX (PowerPoint does not support this) file that are locked in the template, will be locked the same in the output.

Specify Font Substitution

If a font used in the template does not exist on the server generating a report, the font to substitute can be specified.
In addition, if a glyph to be rendered does not exist in the font specified, you can specify the replacement font. This can be set distinctly for European, Bi-Directional, and Far East fonts.

Process Multiple Datasources Simultaneously

If you need this - it's essential. And if you don't need it, it's irrelevant.

Windward enables you to build a document by applying multiple datasources to the template simultaneously. When Windward is merging the data into a template, it processes the template by handling each tag in order, and each tag pulls from different datasources. (As opposed to processing all of one datasource, then processing the next.)

This allows the select tag to use data from another datasource in its select. For example, if you are pulling customer information from one data source, you can then pull data from the sales datasource using the customer ID of the customer presently processing to pull the sales information for that customer. If you're interested in patching together your data from multiple datasources, read this post on our blog.

David Thielen

President/CEO at Windward Studios

From his early years as a Senior Developer at Microsoft, to legendary designer of the popular Enemy Nations strategy game, to reporting and document generation guru, Dave has never lost his passion for building superb software and teams.

Written by:_
David Thielen
President/CEO at Windward Studios
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