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• Analysing and measuring the performance of a .NET application (survey results)

  - by Laila

  Back in December last year, I asked myself: could it be that .NET developers think that you need three days and a PhD to do performance profiling on their code? What if developers are shunning profilers because they perceive them as too complex to use? If so, then what method do they use to measure and analyse the performance of their .NET applications? Do they even care about performance? So, a few weeks ago, I decided to get a 1-minute survey up and running in the hopes that some good, hard data would clear the matter up once and for all. I posted the survey on Simple Talk and got help from a few people to promote it. The survey consisted of 3 simple questions: Amazingly, 533 developers took the time to respond - which means I had enough data to get representative results! So before I go any further, I would like to thank all of you who contributed, because I now have some pretty good answers to the troubling questions I was asking myself. To thank you properly, I thought I would share some of the results with you. First of all, application performance is indeed important to most of you. In fact, performance is an intrinsic part of the development cycle for a good 40% of you, which is much higher than I had anticipated, I have to admit. (I know, "Have a little faith Laila!") When asked what tool you use to measure and analyse application performance, I found that nearly half of the respondents use logging statements, a third use performance counters, and 70% of respondents use a profiler of some sort (a 3rd party performance profilers, the CLR profiler or the Visual Studio profiler). The importance attributed to logging statements did surprise me a little. I am still not sure why somebody would go to the trouble of manually instrumenting code in order to measure its performance, instead of just using a profiler. I personally find the process of annotating code, calculating times from log files, and relating it all back to your source terrifyingly laborious. Not to mention that you then need to remember to turn it all off later! Even when you have logging in place throughout all your code anyway, you still have a fair amount of potentially error-prone calculation to sift through the results; in addition, you'll only get method-level rather than line-level timings, and you won't get timings from any framework or library methods you don't have source for. To top it all, we all know that bottlenecks are rarely where you would expect them to be, so you could be wasting time looking for a performance problem in the wrong place. On the other hand, profilers do all the work for you: they automatically collect the CPU and wall-clock timings, and present the results from method timing all the way down to individual lines of code. Maybe I'm missing a trick. I would love to know about the types of scenarios where you actively prefer to use logging statements. Finally, while a third of the respondents didn't have a strong opinion about code performance profilers, those who had an opinion thought that they were mainly complex to use and time consuming. Three respondents in particular summarised this perfectly: "sometimes, they are rather complex to use, adding an additional time-sink to the process of trying to resolve the existing problem". "they are simple to use, but the results are hard to understand" "Complex to find the more advanced things, easy to find some low hanging fruit". These results confirmed my suspicions: Profilers are seen to be designed for more advanced users who can use them effectively and make sense of the results. I found yet more interesting information when I started comparing samples of "developers for whom performance is an important part of the dev cycle", with those "to whom performance is only looked at in times of crisis", and "developers to whom performance is not important, as long as the app works". See the three graphs below. Sample of developers to whom performance is an important part of the dev cycle: Sample of developers to whom performance is important only in times of crisis: Sample of developers to whom performance is not important, as long as the app works: As you can see, there is a strong correlation between the usage of a profiler and the importance attributed to performance: indeed, the more important performance is to a development team, the more likely they are to use a profiler. In addition, developers to whom performance is an important part of the dev cycle have a higher tendency to use a much wider range of methods for performance measurement and analysis. And, unsurprisingly, the less important performance is, the less varied the methods of measurement are. So all in all, to come back to my random questions: .NET developers do care about performance. Those who care the most use a wider range of performance measurement methods than those who care less. But overall, logging statements, performance counters and third party performance profilers are the performance measurement methods of choice for most developers. Finally, although most of you find code profilers complex to use, those of you who care the most about performance tend to use profilers more than those of you to whom performance is not so important.

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• Is recursion really bad?

  - by dotneteer

  After my previous post about the stack space, it appears that there is perception from the feedback that recursion is bad and we should avoid deep recursion. After writing a compiler, I know that the modern computer and compiler are complex enough and one cannot automatically assume that a hand crafted code would out-perform the compiler optimization. The only way is to do some prototype to find out. So why recursive code may not perform as well? Compilers place frames on a stack. In additional to arguments and local variables, compiles also need to place frame and program pointers on the frame, resulting in overheads. So why hand-crafted code may not performance as well? The stack used by a compiler is a simpler data structure and can grow and shrink cleanly. To replace recursion with out own stack, our stack is allocated in the heap that is far more complicated to manage. There could be overhead as well if the compiler needs to mark objects for garbage collection. Compiler also needs to worry about the memory fragmentation. Then there is additional complexity: CPUs have registers and multiple levels of cache. Register access is a few times faster than in-CPU cache access and is a few 10s times than on-board memory access. So it is up to the OS and compiler to maximize the use of register and in-CPU cache. For my particular problem, I did an experiment to rewrite my c# version of recursive code with a loop and stack approach. So here are the outcomes of the two approaches:   Recursive call Loop and Stack Lines of code for the algorithm 17 46 Speed Baseline 3% faster Readability Clean Far more complex So at the end, I was able to achieve 3% better performance with other drawbacks. My message is never assuming your sophisticated approach would automatically work out better than a simpler approach with a modern computer and compiler. Gage carefully before committing to a more complex approach.

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• Microsoft&rsquo;s new technical computing initiative

  - by Randy Walker

  I made a mental note from earlier in the year.  Microsoft literally buys computers by the truckload.  From what I understand, it’s a typical practice amongst large software vendors.  You plug a few wires in, you test it, and you instantly have mega tera tera flops (don’t hold me to that number).  Microsoft has been trying to plug away at their cloud services (named Azure).  Which, for the layman, means Microsoft runs your software on their computers, and as demand increases you can allocate more computing power on the fly. With this in mind, it doesn’t surprise me that I was recently sent an executive email concerning Microsoft’s new technical computing initiative.  I find it to be a great marketing idea with actual substance behind their real work.  From the programmer academic perspective, in college we dreamed about this type of processing power.  This has decades of computer science theory behind it. A copy of the email received.  (note that I almost deleted this email, thinking it was spam due to it’s length) We don't often think about how complex life really is. Take the relatively simple task of commuting to and from work: it is, in fact, a complicated interplay of variables such as weather, train delays, accidents, traffic patterns, road construction, etc. You can however, take steps to shorten your commute - using a good, predictive understanding of a few of these variables. In fact, you probably are already taking these inputs and instinctively building a predictive model that you act on daily to get to your destination more quickly. Now, when we apply the same method to very complex tasks, this modeling approach becomes much more challenging. Recent world events clearly demonstrated our inability to process vast amounts of information and variables that would have helped to more accurately predict the behavior of global financial markets or the occurrence and impact of a volcano eruption in Iceland. To make sense of issues like these, researchers, engineers and analysts create computer models of the almost infinite number of possible interactions in complex systems. But, they need increasingly more sophisticated computer models to better understand how the world behaves and to make fact-based predictions about the future. And, to do this, it requires a tremendous amount of computing power to process and examine the massive data deluge from cameras, digital sensors and precision instruments of all kinds. This is the key to creating more accurate and realistic models that expose the hidden meaning of data, which gives us the kind of insight we need to solve a myriad of challenges. We have made great strides in our ability to build these kinds of computer models, and yet they are still too difficult, expensive and time consuming to manage. Today, even the most complicated data-rich simulations cannot fully capture all of the intricacies and dependencies of the systems they are trying to model. That is why, across the scientific and engineering world, it is so hard to say with any certainty when or where the next volcano will erupt and what flight patterns it might affect, or to more accurately predict something like a global flu pandemic. So far, we just cannot collect, correlate and compute enough data to create an accurate forecast of the real world. But this is about to change. Innovations in technology are transforming our ability to measure, monitor and model how the world behaves. The implication for scientific research is profound, and it will transform the way we tackle global challenges like health care and climate change. It will also have a huge impact on engineering and business, delivering breakthroughs that could lead to the creation of new products, new businesses and even new industries. Because you are a subscriber to executive e-mails from Microsoft, I want you to be the first to know about a new effort focused specifically on empowering millions of the world's smartest problem solvers. Today, I am happy to introduce Microsoft's Technical Computing initiative. Our goal is to unleash the power of pervasive, accurate, real-time modeling to help people and organizations achieve their objectives and realize their potential. We are bringing together some of the brightest minds in the technical computing community across industry, academia and science at www.modelingtheworld.com to discuss trends, challenges and shared opportunities. New advances provide the foundation for tools and applications that will make technical computing more affordable and accessible where mathematical and computational principles are applied to solve practical problems. One day soon, complicated tasks like building a sophisticated computer model that would typically take a team of advanced software programmers months to build and days to run, will be accomplished in a single afternoon by a scientist, engineer or analyst working at the PC on their desktop. And as technology continues to advance, these models will become more complete and accurate in the way they represent the world. This will speed our ability to test new ideas, improve processes and advance our understanding of systems. Our technical computing initiative reflects the best of Microsoft's heritage. Ever since Bill Gates articulated the then far-fetched vision of "a computer on every desktop" in the early 1980's, Microsoft has been at the forefront of expanding the power and reach of computing to benefit the world. As someone who worked closely with Bill for many years at Microsoft, I am happy to share with you that the passion behind that vision is fully alive at Microsoft and is carried out in the creation of our new Technical Computing group. Enabling more people to make better predictions We have seen the impact of making greater computing power more available firsthand through our investments in high performance computing (HPC) over the past five years. Scientists, engineers and analysts in organizations of all sizes and sectors are finding that using distributed computational power creates societal impact, fuels scientific breakthroughs and delivers competitive advantages. For example, we have seen remarkable results from some of our current customers: Malaria strikes 300,000 to 500,000 people around the world each year. To help in the effort to eradicate malaria worldwide, scientists at Intellectual Ventures use software that simulates how the disease spreads and would respond to prevention and control methods, such as vaccines and the use of bed nets. Technical computing allows researchers to model more detailed parameters for more accurate results and receive those results in less than an hour, rather than waiting a full day. Aerospace engineering firm, a.i. solutions, Inc., needed a more powerful computing platform to keep up with the increasingly complex computational needs of its customers: NASA, the Department of Defense and other government agencies planning space flights. To meet that need, it adopted technical computing. Now, a.i. solutions can produce detailed predictions and analysis of the flight dynamics of a given spacecraft, from optimal launch times and orbit determination to attitude control and navigation, up to eight times faster. This enables them to avoid mistakes in any areas that can cause a space mission to fail and potentially result in the loss of life and millions of dollars. Western & Southern Financial Group faced the challenge of running ever larger and more complex actuarial models as its number of policyholders and products grew and regulatory requirements changed. The company chose an actuarial solution that runs on technical computing technology. The solution is easy for the company's IT staff to manage and adjust to meet business needs. The new solution helps the company reduce modeling time by up to 99 percent - letting the team fine-tune its models for more accurate product pricing and financial projections. Our Technical Computing direction Collaborating closely with partners across industry and academia, we must now extend the reach of technical computing even further to help predictive modelers and data explorers make faster, more accurate predictions. As we build the Technical Computing initiative, we will invest in three core areas: Technical computing to the cloud: Microsoft will play a leading role in bringing technical computing power to scientists, engineers and analysts through the cloud. Existing high- performance computing users will benefit from the ability to augment their on-premises systems with cloud resources that enable 'just-in-time' processing. This platform will help ensure processing resources are available whenever they are needed-reliably, consistently and quickly. Simplify parallel development: Today, computers are shipping with more processing power than ever, including multiple cores, but most modern software only uses a small amount of the available processing power. Parallel programs are extremely difficult to write, test and trouble shoot. However, a consistent model for parallel programming can help more developers unlock the tremendous power in today's modern computers and enable a new generation of technical computing. We are delivering new tools to automate and simplify writing software through parallel processing from the desktop... to the cluster... to the cloud. Develop powerful new technical computing tools and applications: We know scientists, engineers and analysts are pushing common tools (i.e., spreadsheets and databases) to the limits with complex, data-intensive models. They need easy access to more computing power and simplified tools to increase the speed of their work. We are building a platform to do this. Our development efforts will yield new, easy-to-use tools and applications that automate data acquisition, modeling, simulation, visualization, workflow and collaboration. This will allow them to spend more time on their work and less time wrestling with complicated technology. Thinking bigger There is so much left to be discovered and so many questions yet to be answered in the fascinating world around us. We believe the technical computing community will show us that we have not seen anything yet. Imagine just some of the breakthroughs this community could make possible: Better predictions to help improve the understanding of pandemics, contagion and global health trends. Climate change models that predict environmental, economic and human impact, accessible in real-time during key discussions and debates. More accurate prediction of natural disasters and their impact to develop more effective emergency response plans. With an ambitious charter in hand, this new team is ready to build on our progress to-date and execute Microsoft's technical computing vision over the months and years ahead. We will steadily invest in the right technologies, tools and talent, and work to bring together the technical computing community. I invite you to visit www.modelingtheworld.com today. We welcome your ideas and feedback. I look forward to making this journey with you and others who want to answer the world's biggest questions, discover solutions to problems that seem impossible and uncover a host of new opportunities to change the world we live in for the better. Bob

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• Ajax application: using SOAP vs REST ?

  - by coder

  I'm building an ajax heavy application (client-side strictly html/css/js) which will be getting all the data and using server business logic via webservices. I know REST seems to be the hot topic but I can't find any good arguments. The main argument seems to be its "light-weight". My impression so far is that wsdl/soap based services are more expressive and allow for more a more complex transfer of data. It appears that soap would be more useful in the application I'm building where the only code consuming the services will be the js downloaded in the client browser. REST on the other hand seems to have a smaller entry barrier and so can be more useful for services like twitter in allowing other developers to consume these services easily. Also, REST seems to Te better suited for simple data transfers. So in summary SOAP is useful for complex data transfer and REST is useful in simple data transfer. I'm currently under the impression that using SOAP would be best due to the complexity of the messages but perhaps there's other factors. What are your thoughts on the pros/cons of soap/rest for a heavy ajax web app? EDIT: While the wsdl is in xml, the data I'm transferring back and forth is actually in JSON. It just appears more natural to use wsdl/soap here due to the nature of the app. The verbs GET and POST may not be enough. I may want to say something like: processQueue, or executeTimer. This is why my conclusion has been wsdl/soap would be good for bridging a complex layer between two applications (client and server) whereas REST would be better (due to its simplicity) for allowing many developer-users to consume resources programmatically. So you could say the choice falls along two lines Will the app be verb-oriented (completing tasks: use soap) or noun-oriented (consuming resources: use REST) Will the api be consumed by few developers or many developers (REST is strong for many developers)? Since such an ajax heavy app would potentially use many verbs and would only be used by the client developer it appears soap/wsdl would be the best fit.

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• Today's Links (6/21/2011)

  - by Bob Rhubart

  Keeping your process clean: Hiding technology complexity behind a service | Izaak de Hullu Izaak de Hullu offers a solution to "technology pollution like exception handling, technology adapters and correlation." WebLogic Weekly for June 20th, 2011 | James Bayer James Bayer presents "a round-up what has been going on in WebLogic over the past week." Publish to EDN from Java & OSB with JMS | Edwin Biemond Busy blogger and Oracle ACE Edwin Biemond shows "how you can publish events from Java and OSB." How is HTML 5 changing web development? | Audrey Watters - O'Reilly Radar In this interview, OSCON speaker Remy Sharp discusses HTML5's current usage and how it could influence the future of web apps and browsers. SOA Governance Book | SOA Partner Community Blog Information on how those in EMEA can win a free copy of SOA Governance: Governing Shared Services On-Premise and in the Cloud by Thomas Erl, et al. Keeping The Faith on 11i | Floyd Teter "The iceberg is melting, the curtain is coming down, the lights are dimming, the fat lady is singing," says Oracle ACE Director Floyd Teter. Configure and test JMS based EDN in SOA Suite 11g | Edwin Biemond Oracle ACE Edwin Biemond shows you "how to configure EDN-JMS and how to publish an Event to this JMS Queue." Choosing the best way for SOA Suite and Oracle Service Bus to interact with the Oracle Database | Lucas Jellema Oracle ACE Director Lucas Jellema illustrates "over 20 different interaction channels" covering "a fairly wild variation of attributes, required skills, productivity and performance characteristics." Oracle Data Integrator 11.1.1.5 Complex Files as Sources and Targets | Alex Kotopoulis ODI 11.1.1.5 adds the new Complex File technology for use with file sources and targets. The goal is to read or write file structures that are too complex to be parsed using the existing ODI File technology. Java Spotlight Podcast Episode 35: JVM Performance and Quality Featuring an interview with Vladimir Ivanov, Ivan Krylov, and Sergey Kuksenko on the JDK 7 Java Virtual Machine performance and quality. Also includes the Java All Star Developer Panel featuring Dalibor Topic, Java Free and Open Source Software Ambassador, and Alexis Moussine-Pouchkine, Java EE Developer Advocate.

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• Permission based Authorization vs. Role based Authorization - Best Practices - 11g

  - by Prakash Yamuna

  In previous blog posts here and here I have alluded to the support in OWSM for Permission based authorization and Role based authorization support. Recently I was having a conversation with an internal team in Oracle looking to use OWSM for their Web Services security needs and one of the topics was around - When to use permission based authorization vs. role based authorization? As in most scenarios the answer is it depends! There are trade-offs involved in using the two approaches and you need to understand the trade-offs and you need to understand which trade-offs are better for your scenario. Role based Authorization: Simple to use. Just create a new custom OWSM policy and specify the role in the policy (using EM Fusion Middleware Control). Inconsistent if you have multiple type of resources in an application (ex: EJBs, Web Apps, Web Services) - ex: the model for securing EJBs with roles or the model for securing Web App roles - is inconsistent. Since the model is inconsistent, tooling is also fairly inconsistent. Achieving this use-case using JDeveloper is slightly complex - since JDeveloper does not directly support creating OWSM custom policies. Permission based Authorization: More complex. You need to attach both an OWSM policy and create OPSS Permission authorization policies. (Note: OWSM leverages OPSS Permission based Authorization support). More appropriate if you have multiple type of resources in an application (ex: EJBs, Web Apps, Web Services) and want a consistent authorization model. Consistent Tooling for managing authorization across different resources (ex: EM Fusion Middleware Control). Better Lifecycle support in terms of T2P, etc. Achieving this use-case using JDeveloper is slightly complex - since JDeveloper does not directly support creating/editing OPSS Permission based authorization policies.

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• Installing Oracle Event Processing 11g by Antoney Reynolds

  - by JuergenKress

  Earlier this month I was involved in organizing the Monument Family History Day. It was certainly a complex event, with dozens of presenters, guides and 100s of visitors. So with that experience of a complex event under my belt I decided to refresh my acquaintance with Oracle Event Processing (CEP). CEP has a developer side based on Eclipse and a runtime environment. Server install The server install is very straightforward (documentation). It is recommended to use the JRockit JDK with CEP so the steps to set up a working CEP server environment are: Download required software JRockit - I used Oracle “JRockit 6 - R28.2.5” which includes “JRockit Mission Control 4.1” and “JRockit Real Time 4.1”. Oracle Event Processor - I used “Complex Event Processing Release 11gR1 (11.1.1.6.0)” Install JRockit Run the JRockit installer, the download is an executable binary that just needs to be marked as executable. Install CEP Unzip the downloaded file Run the CEP installer, the unzipped file is an executable binary that may need to be marked as executable. Choose a custom install and add the examples if needed. It is not recommended to add the examples to a production environment but they can be helpful in development. Developer Install The developer install requires several steps (documentation). A developer install needs access to the software for the server install, although JRockit isn’t necessary for development use. Read the full article by Antony Reynolds. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress,CEP,Reynolds

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• responsibility for storage

  - by Stefano Borini

  A colleague and I were brainstorming about where to put the responsibility of an object to store itself on the disk in our own file format. There are basically two choices: object.store(file) fileformatWriter.store(object) The first one gives the responsibility of serialization on the disk to the object itself. This is similar to the approach used by python pickle. The second groups the representation responsibility on a file format writer object. The data object is just a plain data container (eventually with additional methods not relevant for storage). We agreed on the second methodology, because it centralizes the writing logic from generic data. We also have cases of objects implementing complex logic that need to store info while the logic is in progress. For these cases, the fileformatwriter object can be passed and used as a delegate, calling storage operations on it. With the first pattern, the complex logic object would instead accept the raw file, and implement the writing logic itself. The first method, however, has the advantage that the object knows how to write and read itself from any file containing it, which may also be convenient. I would like to hear your opinion before starting a rather complex refactoring.

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• Building Queries Systematically

  - by Jeremy Smyth

  The SQL language is a bit like a toolkit for data. It consists of lots of little fiddly bits of syntax that, taken together, allow you to build complex edifices and return powerful results. For the uninitiated, the many tools can be quite confusing, and it's sometimes difficult to decide how to go about the process of building non-trivial queries, that is, queries that are more than a simple SELECT a, b FROM c; A System for Building Queries When you're building queries, you could use a system like the following:  Decide which fields contain the values you want to use in our output, and how you wish to alias those fields Values you want to see in your output Values you want to use in calculations . For example, to calculate margin on a product, you could calculate price - cost and give it the alias margin. Values you want to filter with. For example, you might only want to see products that weigh more than 2Kg or that are blue. The weight or colour columns could contain that information. Values you want to order by. For example you might want the most expensive products first, and the least last. You could use the price column in descending order to achieve that. Assuming the fields you've picked in point 1 are in multiple tables, find the connections between those tables Look for relationships between tables and identify the columns that implement those relationships. For example, The Orders table could have a CustomerID field referencing the same column in the Customers table. Sometimes the problem doesn't use relationships but rests on a different field; sometimes the query is looking for a coincidence of fact rather than a foreign key constraint. For example you might have sales representatives who live in the same state as a customer; this information is normally not used in relationships, but if your query is for organizing events where sales representatives meet customers, it's useful in that query. In such a case you would record the names of columns at either end of such a connection. Sometimes relationships require a bridge, a junction table that wasn't identified in point 1 above but is needed to connect tables you need; these are used in "many-to-many relationships". In these cases you need to record the columns in each table that connect to similar columns in other tables. Construct a join or series of joins using the fields and tables identified in point 2 above. This becomes your FROM clause. Filter using some of the fields in point 1 above. This becomes your WHERE clause. Construct an ORDER BY clause using values from point 1 above that are relevant to the desired order of the output rows. Project the result using the remainder of the fields in point 1 above. This becomes your SELECT clause. A Worked Example   Let's say you want to query the world database to find a list of countries (with their capitals) and the change in GNP, using the difference between the GNP and GNPOld columns, and that you only want to see results for countries with a population greater than 100,000,000. Using the system described above, we could do the following:  The Country.Name and City.Name columns contain the name of the country and city respectively.  The change in GNP comes from the calculation GNP - GNPOld. Both those columns are in the Country table. This calculation is also used to order the output, in descending order To see only countries with a population greater than 100,000,000, you need the Population field of the Country table. There is also a Population field in the City table, so you'll need to specify the table name to disambiguate. You can also represent a number like 100 million as 100e6 instead of 100000000 to make it easier to read. Because the fields come from the Country and City tables, you'll need to join them. There are two relationships between these tables: Each city is hosted within a country, and the city's CountryCode column identifies that country. Also, each country has a capital city, whose ID is contained within the country's Capital column. This latter relationship is the one to use, so the relevant columns and the condition that uses them is represented by the following FROM clause:  FROM Country JOIN City ON Country.Capital = City.ID The statement should only return countries with a population greater than 100,000,000. Country.Population is the relevant column, so the WHERE clause becomes:  WHERE Country.Population > 100e6  To sort the result set in reverse order of difference in GNP, you could use either the calculation, or the position in the output (it's the third column): ORDER BY GNP - GNPOld or ORDER BY 3 Finally, project the columns you wish to see by constructing the SELECT clause: SELECT Country.Name AS Country, City.Name AS Capital,        GNP - GNPOld AS `Difference in GNP`  The whole statement ends up looking like this:  mysql> SELECT Country.Name AS Country, City.Name AS Capital, -> GNP - GNPOld AS `Difference in GNP` -> FROM Country JOIN City ON Country.Capital = City.ID -> WHERE Country.Population > 100e6 -> ORDER BY 3 DESC; +--------------------+------------+-------------------+ | Country            | Capital    | Difference in GNP | +--------------------+------------+-------------------+ | United States | Washington | 399800.00 | | China | Peking | 64549.00 | | India | New Delhi | 16542.00 | | Nigeria | Abuja | 7084.00 | | Pakistan | Islamabad | 2740.00 | | Bangladesh | Dhaka | 886.00 | | Brazil | Brasília | -27369.00 | | Indonesia | Jakarta | -130020.00 | | Russian Federation | Moscow | -166381.00 | | Japan | Tokyo | -405596.00 | +--------------------+------------+-------------------+ 10 rows in set (0.00 sec) Queries with Aggregates and GROUP BY While this system might work well for many queries, it doesn't cater for situations where you have complex summaries and aggregation. For aggregation, you'd start with choosing which columns to view in the output, but this time you'd construct them as aggregate expressions. For example, you could look at the average population, or the count of distinct regions.You could also perform more complex aggregations, such as the average of GNP per head of population calculated as AVG(GNP/Population). Having chosen the values to appear in the output, you must choose how to aggregate those values. A useful way to think about this is that every aggregate query is of the form X, Y per Z. The SELECT clause contains the expressions for X and Y, as already described, and Z becomes your GROUP BY clause. Ordinarily you would also include Z in the query so you see how you are grouping, so the output becomes Z, X, Y per Z.  As an example, consider the following, which shows a count of  countries and the average population per continent:  mysql> SELECT Continent, COUNT(Name), AVG(Population)     -> FROM Country     -> GROUP BY Continent; +---------------+-------------+-----------------+ | Continent     | COUNT(Name) | AVG(Population) | +---------------+-------------+-----------------+ | Asia          |          51 |   72647562.7451 | | Europe        |          46 |   15871186.9565 | | North America |          37 |   13053864.8649 | | Africa        |          58 |   13525431.0345 | | Oceania       |          28 |    1085755.3571 | | Antarctica    |           5 |          0.0000 | | South America |          14 |   24698571.4286 | +---------------+-------------+-----------------+ 7 rows in set (0.00 sec) In this case, X is the number of countries, Y is the average population, and Z is the continent. Of course, you could have more fields in the SELECT clause, and  more fields in the GROUP BY clause as you require. You would also normally alias columns to make the output more suited to your requirements. More Complex Queries  Queries can get considerably more interesting than this. You could also add joins and other expressions to your aggregate query, as in the earlier part of this post. You could have more complex conditions in the WHERE clause. Similarly, you could use queries such as these in subqueries of yet more complex super-queries. Each technique becomes another tool in your toolbox, until before you know it you're writing queries across 15 tables that take two pages to write out. But that's for another day...

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• How to present a stable data model in a public API that allows internal data structures to be changed without breaking the public view of the data?

  - by Max Palmer

  I am in the process of developing an application that allows users to write C# scripts. These scripts allow users to call selected methods and to access and manipulate data in a document. This works well, however, in the development version, scripts access the document's (internal) data structures directly. This means that if we were to change the internal data model/structure, there is a good chance that someone's script will no longer compile. We obviously want to prevent this breaking change from happening, but still want to allow the user to write sensible C# code (whilst not restricting how we develop our internal data model as a result). We therefore need to decouple our scripting API and its data structures from our internal methods and data structures. We've a few ideas as to how we might allow the user to access a what is effectively a stable public version of the document's internal data*, but I wanted to throw the question out there to someone who might have some real experience of this problem. NB our internal document's data structure is quite complex and it could be quite difficult to wrap. We know we want to expose as little as possible in our public API, especially as once it's out there, it's out there for good. Can anyone help? How do scripting languages / APIs decouple their public API and data structures from their internal data structures? Is there no real alternative to having to write a complex interaction layer? If we need to do this, what's a good approach or pattern for wrapping complex data structures that include nested objects, including collections? I've looked at the API facade pattern, which looks like it's trying to address these kinds of issues, but are there alternatives? *One idea is to build a data facade that is kept stable across versions of our application. The facade exposes a set of facade data objects that are used in the script code. These maintain backwards compatibility and wrap access to our internal document's data model.

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• Authorization design-pattern / practice?

  - by Lawtonfogle

  On one end, you have users. On the other end, you have activities. I was wondering if there is a best practice to relate the two. The simplest way I can think of is to have every activity have a role, and assign every user every role they need. The problem is that this gets really messy in practice as soon as you go beyond a trivial system. A way I recently designed was to have users who have roles, and roles have privileges, and activities require some combinations of privileges. For the trivial case, this is more complex, but I think it will scale better. But after I implemented it, I felt like it was overkill for the system I had. Another option would be to have users, who have roles, and activities require you to have a certain role to perform with many activities sharing roles. A more complex variant of this would given activities many possible roles, which you only needed one of. And an even more complex variant would be to allow logical statements of role ownership to use an activity (i.e. Must have A and (B exclusive or C) and must not have D). I could continue to list more, but I think this already gives a picture. And many of these have trade offs. But in software design, there are oftentimes solutions, while perhaps not perfect in every possible case, are clearly top of the pack to an extent it isn't even considered opinion based (i.e. how to store passwords, plain text is worse, hashing better, hashing and salt even better, despite the increased complexity of each level) (i.e. 2, Smart UI designs for applications are bad, even if it is subjective as to what the best design is). So, is there a best practice for authorization design that is not purely opinion based/subjective?

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• Refactoring and Open / Closed principle

  - by Giorgio

  I have recently being reading a web site about clean code development (I do not put a link here because it is not in English). One of the principles advertised by this site is the Open Closed Principle: each software component should be open for extension and closed for modification. E.g., when we have implemented and tested a class, we should only modify it to fix bugs or to add new functionality (e.g. new methods that do not influence the existing ones). The existing functionality and implementation should not be changed. I normally apply this principle by defining an interface I and a corresponding implementation class A. When class A has become stable (implemented and tested), I normally do not modify it too much (possibly, not at all), i.e. If new requirements arrive (e.g. performance, or a totally new implementation of the interface) that require big changes to the code, I write a new implementation B, and keep using A as long as B is not mature. When B is mature, all that is needed is to change how I is instantiated. If the new requirements suggest a change to the interface as well, I define a new interface I' and a new implementation A'. So I, A are frozen and remain the implementation for the production system as long as I' and A' are not stable enough to replace them. So, in view of these observation, I was a bit surprised that the web page then suggested the use of complex refactorings, "... because it is not possible to write code directly in its final form." Isn't there a contradiction / conflict between enforcing the Open / Closed Principle and suggesting the use of complex refactorings as a best practice? Or the idea here is that one can use complex refactorings during the development of a class A, but when that class has been tested successfully it should be frozen?

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• Writing Acceptance test cases

  - by HH_

  We are integrating a testing process in our SCRUM process. My new role is to write acceptance tests of our web applications in order to automate them later. I have read a lot about how tests cases should be written, but none gave me practical advices to write test cases for complex web applications, and instead they threw conflicting principles that I found hard to apply: Test cases should be short: Take the example of a CMS. Short test cases are easy to maintain and to identify the inputs and outputs. But what if I want to test a long series of operations (eg. adding a document, sending a notification to another user, the other user replies, the document changes state, the user gets a notice). It rather seems to me that test cases should represent complete scenarios. But I can see how this will produce overtly complex test documents. Tests should identify inputs and outputs:: What if I have a long form with many interacting fields, with different behaviors. Do I write one test for everything, or one for each? Test cases should be independent: But how can I apply that if testing the upload operation requires that the connect operation is successful? And how does it apply to writing test cases? Should I write a test for each operation, but each test declares its dependencies, or should I rewrite the whole scenario for each test? Test cases should be lightly-documented: This principles is specific to Agile projects. So do you have any advice on how to implement this principle? Although I thought that writing acceptance test cases was going to be simple, I found myself overwhelmed by every decision I had to make (FYI: I am a developer and not a professional tester). So my main question is: What steps or advices do you have in order to write maintainable acceptance test cases for complex applications. Thank you.

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• Interfacing HTTPBuilder and HTMLUnit... some code

  - by Misha Koshelev

  Ok, this isn't even a question: import com.gargoylesoftware.htmlunit.HttpMethod import com.gargoylesoftware.htmlunit.WebClient import com.gargoylesoftware.htmlunit.WebResponseData import com.gargoylesoftware.htmlunit.WebResponseImpl import com.gargoylesoftware.htmlunit.util.Cookie import com.gargoylesoftware.htmlunit.util.NameValuePair import static groovyx.net.http.ContentType.TEXT import java.io.File import java.util.logging.Logger import org.apache.http.impl.cookie.BasicClientCookie /** * HTTPBuilder class * * Allows Javascript processing using HTMLUnit * * @author Misha Koshelev */ class HTTPBuilder { /** * HTTP Builder - implement this way to avoid underlying logging output */ def httpBuilder /** * Logger */ def logger /** * Directory for storing HTML files, if any */ def saveDirectory=null /** * Index of current HTML file in directory */ def saveIdx=1 /** * Current page text */ def text=null /** * Response for processJavascript (Complex Version) */ def resp=null /** * URI for processJavascript (Complex Version) */ def uri=null /** * HttpMethod for processJavascript (Complex Version) */ def method=null /** * Default constructor */ public HTTPBuilder() { // New HTTPBuilder httpBuilder=new groovyx.net.http.HTTPBuilder() // Logging logger=Logger.getLogger(this.class.name) } /** * Constructor that allows saving output files for testing */ public HTTPBuilder(saveDirectory,saveIdx) { this() this.saveDirectory=saveDirectory this.saveIdx=saveIdx } /** * Save text and return corresponding XmlSlurper object */ public saveText() { if (saveDirectory) { def file=new File(saveDirectory.toString()+File.separator+saveIdx+".html") logger.finest "HTTPBuilder.saveText: file=\""+file.toString()+"\"" file<<text saveIdx++ } new XmlSlurper(new org.cyberneko.html.parsers.SAXParser()).parseText(text) } /** * Wrapper around supertype get method */ public Object get(Map<String,?> args) { logger.finer "HTTPBuilder.get: args=\""+args+"\"" args.contentType=TEXT httpBuilder.get(args) { resp,reader-> text=reader.text this.resp=resp this.uri=args.uri this.method=HttpMethod.GET saveText() } } /** * Wrapper around supertype post method */ public Object post(Map<String,?> args) { logger.finer "HTTPBuilder.post: args=\""+args+"\"" args.contentType=TEXT httpBuilder.post(args) { resp,reader-> text=reader.text this.resp=resp this.uri=args.uri this.method=HttpMethod.POST saveText() } } /** * Load cookies from specified file */ def loadCookies(file) { logger.finer "HTTPBuilder.loadCookies: file=\""+file.toString()+"\"" file.withObjectInputStream { ois-> ois.readObject().each { cookieMap-> def cookie=new BasicClientCookie(cookieMap.name,cookieMap.value) cookieMap.remove("name") cookieMap.remove("value") cookieMap.entrySet().each { entry-> cookie."${entry.key}"=entry.value } httpBuilder.client.cookieStore.addCookie(cookie) } } } /** * Save cookies to specified file */ def saveCookies(file) { logger.finer "HTTPBuilder.saveCookies: file=\""+file.toString()+"\"" def cookieMaps=new ArrayList(new LinkedHashMap()) httpBuilder.client.cookieStore.getCookies().each { cookie-> def cookieMap=[:] cookieMap.version=cookie.version cookieMap.name=cookie.name cookieMap.value=cookie.value cookieMap.domain=cookie.domain cookieMap.path=cookie.path cookieMap.expiryDate=cookie.expiryDate cookieMaps.add(cookieMap) } file.withObjectOutputStream { oos-> oos.writeObject(cookieMaps) } } /** * Process Javascript using HTMLUnit (Simple Version) */ def processJavascript() { logger.finer "HTTPBuilder.processJavascript (Simple)" def webClient=new WebClient() def tempFile=File.createTempFile("HTMLUnit","") tempFile<<text def page=webClient.getPage("file://"+tempFile.toString()) webClient.waitForBackgroundJavaScript(10000) text=page.asXml() webClient.closeAllWindows() tempFile.delete() saveText() } /** * Process Javascript using HTMLUnit (Complex Version) * Closure, if specified, used to determine presence of necessary elements */ def processJavascript(closure) { logger.finer "HTTPBuilder.processJavascript (Complex)" // Convert response headers def headers=new ArrayList() resp.allHeaders.each() { header-> headers.add(new NameValuePair(header.name,header.value)) } def responseData=new WebResponseData(text.bytes,resp.statusLine.statusCode,resp.statusLine.toString(),headers) def response=new WebResponseImpl(responseData,uri.toURL(),method,0) // Transfer cookies def webClient=new WebClient() httpBuilder.client.cookieStore.getCookies().each { cookie-> webClient.cookieManager.addCookie(new Cookie(cookie.domain,cookie.name,cookie.value,cookie.path,cookie.expiryDate,cookie.isSecure())) } def page=webClient.loadWebResponseInto(response,webClient.getCurrentWindow()) // Wait for condition if (closure) { for (i in 1..20) { if (closure(page)) { break; } synchronized(page) { page.wait(500); } } } // Return text text=page.asXml() webClient.closeAllWindows() saveText() } } Allows one to interface HTTPBuilder with HTMLUnit! Enjoy Misha

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• Helping linqtosql datacontext use implicit conversion between varchar column in the database and tab

  - by user213256

  I am creating an mssql database table, "Orders", that will contain a varchar(50) field, "Value" containing a string that represents a slightly complex data type, "OrderValue". I am using a linqtosql datacontext class, which automatically types the "Value" column as a string. I gave the "OrderValue" class implicit conversion operators to and from a string, so I can easily use implicit conversion with the linqtosql classes like this: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // use implicit converstion to turn the string representation of the order // value into the complex data type. OrderValue value = order.Value; // adjust one of the fields in the complex data type value.Shipping += 10; // use implicit conversion to store the string representation of the complex // data type back in the linqtosql order object order.Value = value; // save changes db.SubmitChanges(); However, I would really like to be able to tell the linqtosql class to type this field as "OrderValue" rather than as "string". Then I would be able to avoid complex code and re-write the above as: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // The Value field is already typed as the "OrderValue" type rather than as string. // When a string value was read from the database table, it was implicity converted // to "OrderValue" type. order.Value.Shipping += 10; // save changes db.SubmitChanges(); In order to achieve this desired goal, I looked at the datacontext designer and selected the "Value" field of the "Order" table. Then, in properties, I changed "Type" to "global::MyApplication.OrderValue". The "Server Data Type" property was left as "VarChar(50) NOT NULL" The project built without errors. However, when reading from the database table, I was presented with the following error message: Could not convert from type 'System.String' to type 'MyApplication.OrderValue'. at System.Data.Linq.DBConvert.ChangeType(Object value, Type type) at Read_Order(ObjectMaterializer1 ) at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Example.OrdersProvider.GetOrders() at ... etc From the stack trace, I believe this error is happening while reading the data from the table. When presented with converting a string to my custom data type, even though the implicit conversion operators are present, the DBConvert class gets confused and throws an error. Is there anything I can do to help it not get confused and do the implicit conversion? Thanks in advance, and apologies if I have posted in the wrong forum. cheers / Ben

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• Looking for a workaround for IE 6/7 "Unspecified Error" bug when accessing offsetParent; using ASP.N

  - by CodeChef

  I'm using jQuery UI's draggable and droppable libraries in a simple ASP.NET proof of concept application. This page uses the ASP.NET AJAX UpdatePanel to do partial page updates. The page allows a user to drop an item into a trashcan div, which will invoke a postback that deletes a record from the database, then rebinds the list (and other controls) that the item was drug from. All of these elements (the draggable items and the trashcan div) are inside an ASP.NET UpdatePanel. Here is the dragging and dropping initialization script: function initDragging() { $(".person").draggable({helper:'clone'}); $("#trashcan").droppable({ accept: '.person', tolerance: 'pointer', hoverClass: 'trashcan-hover', activeClass: 'trashcan-active', drop: onTrashCanned }); } $(document).ready(function(){ initDragging(); var prm = Sys.WebForms.PageRequestManager.getInstance(); prm.add_endRequest(function() { initDragging(); }); }); function onTrashCanned(e,ui) { var id = $('input[id$=hidID]', ui.draggable).val(); if (id != undefined) { $('#hidTrashcanID').val(id); __doPostBack('btnTrashcan',''); } } When the page posts back, partially updating the UpdatePanel's content, I rebind the draggables and droppables. When I then grab a draggable with my cursor, I get an "htmlfile: Unspecified error." exception. I can resolve this problem in the jQuery library by replacing elem.offsetParent with calls to this function that I wrote: function IESafeOffsetParent(elem) { try { return elem.offsetParent; } catch(e) { return document.body; } } I also have to avoid calls to elem.getBoundingClientRect() as it throws the same error. For those interested, I only had to make these changes in the jQuery.fn.offset function in the Dimensions Plugin. My questions are: Although this works, are there better ways (cleaner; better performance; without having to modify the jQuery library) to solve this problem? If not, what's the best way to manage keeping my changes in sync when I update the jQuery libraries in the future? For, example can I extend the library somewhere other than just inline in the files that I download from the jQuery website. Update: @some It's not publicly accessible, but I will see if SO will let me post the relevant code into this answer. Just create an ASP.NET Web Application (name it DragAndDrop) and create these files. Don't forget to set Complex.aspx as your start page. You'll also need to download the jQuery UI drag and drop plug in as well as jQuery core Complex.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Complex.aspx.cs" Inherits="DragAndDrop.Complex" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Untitled Page</title> <script src="jquery-1.2.6.min.js" type="text/javascript"></script> <script src="jquery-ui-personalized-1.5.3.min.js" type="text/javascript"></script> <script type="text/javascript"> function initDragging() { $(".person").draggable({helper:'clone'}); $("#trashcan").droppable({ accept: '.person', tolerance: 'pointer', hoverClass: 'trashcan-hover', activeClass: 'trashcan-active', drop: onTrashCanned }); } $(document).ready(function(){ initDragging(); var prm = Sys.WebForms.PageRequestManager.getInstance(); prm.add_endRequest(function() { initDragging(); }); }); function onTrashCanned(e,ui) { var id = $('input[id$=hidID]', ui.draggable).val(); if (id != undefined) { $('#hidTrashcanID').val(id); __doPostBack('btnTrashcan',''); } } </script> </head> <body> <form id="form1" runat="server"> <asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager> <div> <asp:UpdatePanel ID="updContent" runat="server" UpdateMode="Always"> <ContentTemplate> <asp:LinkButton ID="btnTrashcan" Text="trashcan" runat="server" CommandName="trashcan" onclick="btnTrashcan_Click" style="display:none;"></asp:LinkButton> <input type="hidden" id="hidTrashcanID" runat="server" /> <asp:Button ID="Button1" runat="server" Text="Save" onclick="Button1_Click" /> <table> <tr> <td style="width: 300px;"> <asp:DataList ID="lstAllPeople" runat="server" DataSourceID="odsAllPeople" DataKeyField="ID"> <ItemTemplate> <div class="person"> <asp:HiddenField ID="hidID" runat="server" Value='<%# Eval("ID") %>' /> Name: <asp:Label ID="lblName" runat="server" Text='<%# Eval("Name") %>' /> <br /> <br /> </div> </ItemTemplate> </asp:DataList> <asp:ObjectDataSource ID="odsAllPeople" runat="server" SelectMethod="SelectAllPeople" TypeName="DragAndDrop.Complex+DataAccess" onselecting="odsAllPeople_Selecting"> <SelectParameters> <asp:Parameter Name="filter" Type="Object" /> </SelectParameters> </asp:ObjectDataSource> </td> <td style="width: 300px;vertical-align:top;"> <div id="trashcan"> drop here to delete </div> <asp:DataList ID="lstPeopleToDelete" runat="server" DataSourceID="odsPeopleToDelete"> <ItemTemplate> ID: <asp:Label ID="IDLabel" runat="server" Text='<%# Eval("ID") %>' /> <br /> Name: <asp:Label ID="NameLabel" runat="server" Text='<%# Eval("Name") %>' /> <br /> <br /> </ItemTemplate> </asp:DataList> <asp:ObjectDataSource ID="odsPeopleToDelete" runat="server" onselecting="odsPeopleToDelete_Selecting" SelectMethod="GetDeleteList" TypeName="DragAndDrop.Complex+DataAccess"> <SelectParameters> <asp:Parameter Name="list" Type="Object" /> </SelectParameters> </asp:ObjectDataSource> </td> </tr> </table> </ContentTemplate> </asp:UpdatePanel> </div> </form> </body> </html> Complex.aspx.cs namespace DragAndDrop { public partial class Complex : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected List<int> DeleteList { get { if (ViewState["dl"] == null) { List<int> dl = new List<int>(); ViewState["dl"] = dl; return dl; } else { return (List<int>)ViewState["dl"]; } } } public class DataAccess { public IEnumerable<Person> SelectAllPeople(IEnumerable<int> filter) { return Database.SelectAll().Where(p => !filter.Contains(p.ID)); } public IEnumerable<Person> GetDeleteList(IEnumerable<int> list) { return Database.SelectAll().Where(p => list.Contains(p.ID)); } } protected void odsAllPeople_Selecting(object sender, ObjectDataSourceSelectingEventArgs e) { e.InputParameters["filter"] = this.DeleteList; } protected void odsPeopleToDelete_Selecting(object sender, ObjectDataSourceSelectingEventArgs e) { e.InputParameters["list"] = this.DeleteList; } protected void Button1_Click(object sender, EventArgs e) { foreach (int id in DeleteList) { Database.DeletePerson(id); } DeleteList.Clear(); lstAllPeople.DataBind(); lstPeopleToDelete.DataBind(); } protected void btnTrashcan_Click(object sender, EventArgs e) { int id = int.Parse(hidTrashcanID.Value); DeleteList.Add(id); lstAllPeople.DataBind(); lstPeopleToDelete.DataBind(); } } } Database.cs namespace DragAndDrop { public static class Database { private static Dictionary<int, Person> _people = new Dictionary<int,Person>(); static Database() { Person[] people = new Person[] { new Person("Chad") , new Person("Carrie") , new Person("Richard") , new Person("Ron") }; foreach (Person p in people) { _people.Add(p.ID, p); } } public static IEnumerable<Person> SelectAll() { return _people.Values; } public static void DeletePerson(int id) { if (_people.ContainsKey(id)) { _people.Remove(id); } } public static Person CreatePerson(string name) { Person p = new Person(name); _people.Add(p.ID, p); return p; } } public class Person { private static int _curID = 1; public int ID { get; set; } public string Name { get; set; } public Person() { ID = _curID++; } public Person(string name) : this() { Name = name; } } }

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• Simplifying Testing through design considerations while utilizing dependency injection

  - by Adam Driscoll

  We are a few months into a green-field project to rework the Logic and Business layers of our product. By utilizing MEF (dependency injection) we have achieved high levels of code coverage and I believe that we have a pretty solid product. As we have been working through some of the more complex logic I have found it increasingly difficult to unit test. We are utilizing the CompositionContainer to query for types required by these complex algorithms. My unit tests are sometimes difficult to follow due to the lengthy mock object setup process that must take place, just right, to allow for certain circumstances to be verified. My unit tests often take me longer to write than the code that I'm trying to test. I realize this is not only an issue with dependency injection but with design as a whole. Is poor method design or lack of composition to blame for my overly complex tests? I've tried base classing tests, creating commonly used mock objects and ensuring that I utilize the container as much as possible to ease this issue but my tests always end up quite complex and hard to debug. What are some tips that you've seen to keep such tests concise, readable, and effective?

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• Parsing every part of an HTTP header field-value

  - by brickner

  Hi all. I'm parsing HTTP data directly from packets (either TCP reconstructed or not, you can assume it is). I'm looking for the best way to parse HTTP as accurately as possible. The main issue here is the HTTP header. Looking at the basic RFC of HTTP/1.1, it seems that HTTP header parsing would be complex. The RFC describes very complex regular expressions for different parts of the header. Should I write these regular expressions to parse the different parts of the HTTP header? The basic parsing I've written so far for HTTP header is for the generic HTTP header: message-header = field-name ":" [ field-value ] And I've included replacing inner LWS with SP and repeating headers with the same field-name with comma separated values as described in section 4.2. However, looking at section 14.9 for example would show that in order to parse the different parts of the field-value I need a much more complex parsing scheme. How do you suggest I should handle the complex parts of HTTP parsing (specifically the field-value) assuming I want to give the parser users the full capabilities of HTTP and to parse every part of HTTP? Design suggestions for this would also be appreciated. Thanks.

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• Delphi fastMM doesn't work with operator "IS"

  - by Joc02

  I work on Delphi project who interac with many other small libraries. I use FastMM4 and I would like work with complex classes passed on dll parameter. So for exemple I send my form to my dll. Into the dll I test the type of parameter with the operator "IS". But into the Dll the operator "IS" return always "false" Exemple library Dll; uses FastMM4, System.SysUtils, System.Classes, Vcl.Dialogs, Vcl.Forms; {$R *.res} procedure Complex(L : TObject);stdcall; begin if L is TForm then showmessage('Ok') else showmessage('Pas ok') ; if L is TCustomFrame then showmessage('Ok') else showmessage('Pas ok') end; exports Complex; begin end. And the call procedure TffsIsOperator.Button2Click(Sender: TObject); var MaDLL : THandle; Proc : procedure (l : TForm); begin try MaDLL := LoadLibrary(PChar('Dll.dll')); @Proc := GetProcAddress(MaDLL, 'Complex'); Proc(self); finally FreeLibrary(MaDLL); end; end;

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• c++ tables of unions and structures

  - by newbDeveloper

  I was told to write a program, that creates a union and structure, then creates two-element arrays of unions and structures and fills their fields. I have created a union and a structure, but how to fill their fields in arrays ? #include <iostream> #include <stdlib.h> #include <stdio.h> using namespace std; union complex; union complex{ int i1; long double ld1; } u; struct Person { char* name; int age; bool sex; void show(){ printf("name %s, age %2.0d, sex %1d\n", name , age, sex); }; } person; int main(void) { Person *o = new Person[2]; complex *un = new complex[2]; un[0]->i1=i; system("pause"); return 0; } I've tried un[0]-i1=i; but it's not the proper way to do this.

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• AutoMapper MappingFunction from Source Type of NameValueCollection

  - by REA_ANDREW

  I have had a situation arise today where I need to construct a complex type from a source of a NameValueCollection.  A little while back I submitted a patch for the Agatha Project to include REST (JSON and XML) support for the service contract.  I realized today that as useful as it is, it did not actually support true REST conformance, as REST should support GET so that you can use JSONP from JavaScript directly meaning you can query cross domain services.  My original implementation for POX and JSON used the POST method and this immediately rules out JSONP as from reading, JSONP only works with GET Requests. This then raised another issue.  The current operation contract of Agatha and one of its main benefits is that you can supply an array of Request objects in a single request, limiting the about of server requests you need to make.  Now, at the present time I am thinking that this will not be the case for the REST imlementation but will yield the benefits of the fact that : The same Request objects can be used for SOAP and RST (POX, JSON) The construct of the JavaScript functions will be simpler and more readable It will enable the use of JSONP for cross domain REST Services The current contract for the Agatha WcfRequestProcessor is at time of writing the following: [ServiceContract] public interface IWcfRequestProcessor { [OperationContract(Name = "ProcessRequests")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] Response[] Process(params Request[] requests); [OperationContract(Name = "ProcessOneWayRequests", IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] void ProcessOneWayRequests(params OneWayRequest[] requests); }   My current proposed solution, and at the very early stages of my concept is as follows: [ServiceContract] public interface IWcfRestJsonRequestProcessor { [OperationContract(Name="process")] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [TransactionFlow(TransactionFlowOption.Allowed)] [WebGet(UriTemplate = "process/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] Response[] Process(string name, NameValueCollection parameters); [OperationContract(Name="processoneway",IsOneWay = true)] [ServiceKnownType("GetKnownTypes", typeof(KnownTypeProvider))] [WebGet(UriTemplate = "process-one-way/{name}/{*parameters}", BodyStyle = WebMessageBodyStyle.WrappedResponse, ResponseFormat = WebMessageFormat.Json)] void ProcessOneWayRequests(string name, NameValueCollection parameters); }   Now this part I have not yet implemented, it is the preliminart step which I have developed which will allow me to take the name of the Request Type and the NameValueCollection and construct the complex type which is that of the Request which I can then supply to a nested instance of the original IWcfRequestProcessor  and work as it should normally.  To give an example of some of the urls which you I envisage with this method are: http://www.url.com/service.svc/json/process/getweather/?location=london http://www.url.com/service.svc/json/process/getproductsbycategory/?categoryid=1 http://www.url.om/service.svc/json/process/sayhello/?name=andy Another reason why my direction has gone to a single request for the REST implementation is because of restrictions which are imposed by browsers on the length of the url.  From what I have read this is on average 2000 characters.  I think that this is a very acceptable usage limit in the context of using 1 request, but I do not think this is acceptable for accommodating multiple requests chained together.  I would love to be corrected on that one, I really would but unfortunately from what I have read I have come to the conclusion that this is not the case. The mapping function So, as I say this is just the first pass I have made at this, and I am not overly happy with the try catch for detecting types without default constructors.  I know there is a better way but for the minute, it escapes me.  I would also like to know the correct way for adding mapping functions and not using the anonymous way that I have used.  To achieve this I have used recursion which I am sure is what other mapping function use. As you do have to go as deep as the complex type is. public static object RecurseType(NameValueCollection collection, Type type, string prefix) { try { var returnObject = Activator.CreateInstance(type); foreach (var property in type.GetProperties()) { foreach (var key in collection.AllKeys) { if (String.IsNullOrEmpty(prefix) || key.Length > prefix.Length) { var propertyNameToMatch = String.IsNullOrEmpty(prefix) ? key : key.Substring(property.Name.IndexOf(prefix) + prefix.Length + 1); if (property.Name == propertyNameToMatch) { property.SetValue(returnObject, Convert.ChangeType(collection.Get(key), property.PropertyType), null); } else if(property.GetValue(returnObject,null) == null) { property.SetValue(returnObject, RecurseType(collection, property.PropertyType, String.Concat(prefix, property.PropertyType.Name)), null); } } } } return returnObject; } catch (MissingMethodException) { //Quite a blunt way of dealing with Types without default constructor return null; } }   Another thing is performance, I have not measured this in anyway, it is as I say the first pass, so I hope this can be the start of a more perfected implementation.  I tested this out with a complex type of three levels, there is no intended logical meaning to the properties, they are simply for the purposes of example.  You could call this a spiking session, as from here on in, now I know what I am building I would take a more TDD approach.  OK, purists, why did I not do this from the start, well I didn’t, this was a brain dump and now I know what I am building I can. The console test and how I used with AutoMapper is as follows: static void Main(string[] args) { var collection = new NameValueCollection(); collection.Add("Name", "Andrew Rea"); collection.Add("Number", "1"); collection.Add("AddressLine1", "123 Street"); collection.Add("AddressNumber", "2"); collection.Add("AddressPostCodeCountry", "United Kingdom"); collection.Add("AddressPostCodeNumber", "3"); AutoMapper.Mapper.CreateMap<NameValueCollection, Person>() .ConvertUsing(x => { return(Person) RecurseType(x, typeof(Person), null); }); var person = AutoMapper.Mapper.Map<NameValueCollection, Person>(collection); Console.WriteLine(person.Name); Console.WriteLine(person.Number); Console.WriteLine(person.Address.Line1); Console.WriteLine(person.Address.Number); Console.WriteLine(person.Address.PostCode.Country); Console.WriteLine(person.Address.PostCode.Number); Console.ReadLine(); }   Notice the convention that I am using and that this method requires you do use.  Each property is prefixed with the constructed name of its parents combined.  This is the convention used by AutoMapper and it makes sense. I can also think of other uses for this including using with ASP.NET MVC ModelBinders for creating a complex type from the QueryString which is itself is a NameValueCollection. Hope this is of some help to people and I would welcome any code reviews you could give me. References: Agatha : http://code.google.com/p/agatha-rrsl/ AutoMapper : http://automapper.codeplex.com/   Cheers for now, Andrew   P.S. I will have the proposed solution for a more complete REST implementation for AGATHA very soon. 

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• Portal And Content - Content Integration - Best Practices

  - by Stefan Krantz

  Lately we have seen an increase in projects that have failed to either get user friendly content integration or non satisfactory performance. Our intention is to mitigate any knowledge gap that our previous post might have left you with, therefore this post will repeat some recommendation or reference back to old useful post. Moreover this post will help you understand ground up how to design, architect and implement business enabled, responsive and performing portals with complex requirements on business centric information publishing. Design the Information Model The key to successful portal deployments is Information modeling, it's a key task to understand the use case you designing for, therefore I have designed a set of question you need to ask yourself or your customer: Question: Who will own the content, IT or Business? Answer: BusinessQuestion: Who will publish the content, IT or Business? Answer: BusinessQuestion: Will there be multiple publishers? Answer: YesQuestion: Are the publishers computer scientist?Answer: NoQuestion: How often do the information changes, daily, weekly, monthly?Answer: Daily, weekly If your answers to the questions matches at least 2, we strongly recommend you design your content with following principles: Divide your pages in to logical sections, where each section is marked with its purpose Assign capabilities to each section, does it contain text, images, formatting and/or is it static and is populated through other contextual information Select editor/design element type WYSIWYG - Rich Text Plain Text - non-format text Image - Image object Static List - static list of formatted informationDynamic Data List - assembled information from multiple data files through CMIS query The result of such design map could look like following below examples: Based on the outcome of the required elements in the design column 3 from the left you will now simply design a data model in WebCenter Content - Site Studio by creating a Region Definition structure matching your design requirements.For more information on how to create a Region definition see following post: Region Definition Post - note see instruction 7 for details. Each region definition can now be used to instantiate data files, a data file will hold the actual data for each element in the region definition. Another way you can see this is to compare the region definition as an extension to the metadata model in WebCenter Content for each data file item. Design content templates With a solid dependable information model we can now proceed to template creation and page design, in this phase focuses on how to place the content sections from the region definition on the page via a Content Presenter template. Remember by creating content presenter templates you will leverage the latest and most integrated technology WebCenter has to offer. This phase is much easier since the you already have the information model and design wire-frames to base the logic on, however there is still few considerations to pay attention to: Base the template on ADF and make only necessary exceptions to markup when required Leverage ADF design components for Tabs, Accordions and other similar components, this way the design in the content published areas will comply with other design areas based on custom ADF taskflows There is no performance impact when using meta data or region definition based data All data access regardless of type, metadata or xml data it can be accessed via the Content Presenter - Node. See below for applied examples on how to access data Access metadata property from Document - #{node.propertyMap['myProp'].value}myProp in this example can be for instance (dDocName, dDocTitle, xComments or any other available metadata) Access element data from data file xml - #{node.propertyMap['[Region Definition Name]:[Element name]'].asTextHtml}Region Definition Name is the expect region definition that the current data file is instantiatingElement name is the element value you like to grab from the data file I recommend you read following  useful post on content template topic:CMIS queries and template creation - note see instruction 9 for detailsStatic List template rendering For more information on templates:Single Item Content TemplateMulti Item Content TemplateExpression Language Internationalization Considerations When integrating content assets via content presenter you by now probably understand that the content item/data file is wired to the page, what is also pretty common at this stage is that the content item/data file only support one language since its not practical or business friendly to mix that into a complex structure. Therefore you will be left with a very common dilemma that you will have to either build a complete new portal for each locale, which is not an good option! However with little bit of information modeling and clear naming convention this can be addressed. Basically you can simply make sure that all content item/data file are named with a predictable naming convention like "Content1_EN" for the English rendition and "Content1_ES" for the Spanish rendition. This way through simple none complex customizations you will be able to dynamically switch the actual content item/data file just before rendering. By following proposed approach above you not only enable a simple mechanism for internationalized content you also preserve the functionality in the content presenter to support business accessible run-time publishing of information on existing and new pages. I recommend you read following useful post on Internationalization topics:Internationalize with Content Presenter Integrate with Review & Approval processes Today the Review and approval functionality and configuration is based out of WebCenter Content - Criteria Workflows. Criteria Workflows uses the metadata of the checked in document to evaluate if the document is under any review/approval process. So for instance if a Criteria Workflow is configured to force any documents with Version = "2" or "higher" and Content Type is "Instructions", any matching content item version on check in will now enter the workflow before getting released for general access. Few things to consider when configuring Criteria Workflows: Make sure to not trigger on version one for Content Items that are Data Files - if you trigger on version 1 you will not only approve an empty document you will also have a content presenter pointing to a none existing document - since the document will only be available after successful completion of the workflow Approval workflows sometimes requires more complex criteria, the recommendation if that is the case is that the meta data triggering such criteria is automatically populated, this can be achieved through many approaches including Content Profiles Criteria workflows are configured and managed in WebCenter Content Administration Applets where you can configure one or more workflows. When you configured Criteria workflows the Content Presenter will support the editors with the approval process directly inline in the "Contribution mode" of the portal. In addition to approve/reject and details of the task, the content presenter natively support the user to view the current and future version of the change he/she is approving. See below for example: Architectural recommendation To support review&approval processes - minimize the amount of data files per page Each CMIS query can consume significant time depending on the complexity of the query - minimize the amount of CMIS queries per page Use Content Presenter Templates based on ADF - this way you minimize the design considerations and optimize the usage of caching Implement the page in as few Data files as possible - simplifies publishing process, increases performance and simplifies release process Named data file (node) or list of named nodes when integrating to pages increases performance vs. querying for data Named data file (node) or list of named nodes when integrating to pages enables business centric page creation and publishing and reduces the need for IT department interaction Summary Just because one architectural decision solves a business problem it doesn't mean its the right one, when designing portals all architecture has to be in harmony and not impacting each other. For instance the most technical complex solution is not always the best since it will most likely defeat the business accessibility, performance or both, therefore the best approach is to first design for simplicity that even a non-technical user can operate, after that consider the performance impact and final look at the technology challenges these brings and workaround them first with out-of-the-box features, after that design and develop functions to complement the short comings.

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• Orchestrating the Virtual Enterprise

  - by John Murphy

  During the American Industrial Revolution, the Ford Motor Company did it all. It turned raw materials into a showroom full of Model Ts. It owned a steel mill, a glass factory, and an automobile assembly line. The company was both self-sufficient and innovative and went on to become one of the largest and most profitable companies in the world. Nowadays, it's unusual for any business to follow this vertical integration model because its much harder to be best in class across such a wide a range of capabilities and services. Instead, businesses focus on their core competencies and outsource other business functions to specialized suppliers. They exchange vertical integration for collaboration. When done well, all parties benefit from this arrangement and the collaboration leads to the creation of an agile, lean and successful "virtual enterprise." Case in point: For Sun hardware, Oracle outsources most of its manufacturing and all of its logistics to third parties. These are vital activities, but ones where Oracle doesn't have a core competency, so we shift them to business partners who do. Within our enterprise, we always retain the core functions of product development, support, and most of the sales function, because that's what constitutes our core value to our customers. This is a perfect example of a virtual enterprise.  What are the implications of this? It means that we must exchange direct internal control for indirect external collaboration. This fundamentally changes the relative importance of different business processes, the boundaries of security and information sharing, and the relationship of the supply chain systems to the ERP. The challenge is that the systems required to support this virtual paradigm are still mired in "island enterprise" thinking. But help is at hand. Developments such as the Web, social networks, collaboration, and rules-based orchestration offer great potential to fundamentally re-architect supply chain systems to better support the virtual enterprise.  Supply Chain Management Systems in a Virtual Enterprise Historically enterprise software was constructed to automate the ERP - and then the supply chain systems extended the ERP. They were joined at the hip. In virtual enterprises, the supply chain system needs to be ERP agnostic, sitting above each of the ERPs that are distributed across the virtual enterprise - most of which are operating in other businesses. This is vital so that the supply chain system can manage the flow of material and the related information through the multiple enterprises. It has to have strong collaboration tools. It needs to be highly flexible. Users need to be able to see information that's coming from multiple sources and be able to react and respond to events across those sources.  Oracle Fusion Distributed Order Orchestration (DOO) is a perfect example of a supply chain system designed to operate in this virtual way. DOO embraces the idea that a company's fulfillment challenge is a distributed, multi-enterprise problem. It enables users to manage the process and the trading partners in a uniform way and deliver a consistent user experience while operating over a heterogeneous, virtual enterprise. This is a fundamental shift at the core of managing supply chains. It forces virtual enterprises to think architecturally about how best to construct their supply chain systems.  Case in point, almost everyone has ordered from Amazon.com at one time or another. Our orders are as likely to be fulfilled by third parties as they are by Amazon itself. To deliver the order promptly and efficiently, Amazon has to send it to the right fulfillment location and know the availability in that location. It needs to be able to track status of the fulfillment and deal with exceptions. As a virtual enterprise, Amazon's operations, using thousands of trading partners, requires a very different approach to fulfillment than the traditional 'take an order and ship it from your own warehouse' model. Amazon had no choice but to develop a complex, expensive and custom solution to tackle this problem as there used to be no product solution available. Now, other companies who want to follow similar models have a better off-the-shelf choice -- Oracle Distributed Order Orchestration (DOO).  Consider how another of our customers is using our distributed orchestration solution. This major airplane manufacturer has a highly complex business and interacts regularly with the U.S. Government and major airlines. It sits in the middle of an intricate supply chain and needed to improve visibility across its many different entities. Oracle Fusion DOO gives the company an orchestration mechanism so it could improve quality, speed, flexibility, and consistency without requiring an organ transplant of these highly complex legacy systems. Many retailers face the challenge of dealing with brick and mortar, Web, and reseller channels. They all need to be knitted together into a virtual enterprise experience that is consistent for their customers. When a large U.K. grocer with a strong brick and mortar retail operation added an online business, they turned to Oracle Fusion DOO to bring these entities together. Disturbing the Peace with Acquisitions Quite often a company's ERP system is disrupted when it acquires a new company. An acquisition can inject a new set of processes and systems -- or even introduce an entirely new business like Sun's hardware did at Oracle. This challenge has been a driver for some of our DOO customers. A large power management company is using Oracle Fusion DOO to provide the flexibility to rapidly integrate additional products and services into its central fulfillment operation. The Flip Side of Fulfillment Meanwhile, we haven't ignored similar challenges on the supply side of the equation. Specifically, how to manage complex supply in a flexible way when there are multiple trading parties involved? How to manage the supply to suppliers? How to manage critical components that need to merge in a tier two or tier three supply chain? By investing in supply orchestration solutions for the virtual enterprise, we plan to give users better visibility into their network of suppliers to help them drive down costs. We also think this technology and full orchestration process can be applied to the financial side of organizations. An example is transactions that flow through complex internal structures to minimize tax exposure. We can help companies manage those transactions effectively by thinking about the internal organization as a virtual enterprise and bringing the same solution set to this internal challenge.  The Clear Front Runner No other company is investing in solving the virtual enterprise supply chain issues like Oracle is. Oracle is in a unique position to become the gold standard in this market space. We have the infrastructure of Oracle technology. We already have an Oracle Fusion DOO application which embraces the best of what's required in this area. And we're absolutely committed to extending our Fusion solution to other use cases and delivering even more business value.

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• Reading Hindi (Devanagari) on Windows XP SP1

  - by user31670

  Pretty much all the text that I have read on enabling Hindi (Complex Text Rendering) involve enabling it via Regional Settings Languages Install files for complex script support and left to right languages (including Thai). However, I am able to read Wikipedia without having this feature enabled. Is this normal or is this an anomaly with my Win XP SP1 CD?

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• Strange behaviour of code inside TransactionScope?

  - by Krishna

  We are facing a very complex issue in our production application. We have a WCF method which creates a complex Entity in the database with all its relation. public void InsertEntity(Entity entity) { using(TransactionScope scope = new TransactionScope()) { EntityDao.Create(entity); } } EntityDao.Create(entity) method is very complex and has huge pieces of logic. During the entire process of creation it creates several child entities and also have several queries to database. During the entire WCF request of entity creation usually Connection is maintained in a ThreadStatic variable and reused by the DAOs. Although some of the queries in DAO described in step 2 uses a new connection and closes it after use. Overall we have seen that the above process behaviour is erratic. Some of the queries in the inner DAO does not even return actual data from the database? The same query when run to the actaul data store gives correct result. What can be possible reason of this behaviour?

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