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  • How to Conduct a Website Self Evaluation

    Site owners looking to improve recognition and performance may wish to take some time to evaluate its present level of operation. Site owners recently completing improvements may look to see how these changes have affected site performance. The question remains: Where Do I Start?

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  • Using Coalesce

    - by Derek Dieter
    The coalesce function is used to find the first non-null value. The function takes limitless number of parameters in order to evaluate the first non null. If all the parameters are null, then COALESCE will also return a NULL value.-- hard coded example SELECT MyValue = COALESCE(NULL, NULL, 'abc', 123)The example above returns back [...]

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  • Encapsulating code in F# (Part 1)

    - by MarkPearl
    I have been looking at F# for a while now and seem a few really interesting samples and snippets on howto’s. This has been great to see the basic outline of the language and the possibilities, however a nagging question in the back of my mind has been what does an F# project look like? How do I code group code in F# so that it can be modularized and brought in and out of a project easily? My Expert F# book has an entire chapter (7) dedicated to this and after browsing the other chapters of the book I decided that this topic was something I really wanted to know more about now! Because of my C# background I keep trying to think in F# of objects. So to try and get a clearer idea of how to do things the F# way I am first going to take a very simplified C# example and try to “translate” it. using System; namespace ConsoleApplication1 { namespace ExampleOfEncapsulationInCSharp { class Program { static void EncapsulatedVariableInAMethod() { int count = 10; Console.WriteLine(count); } static void Main(string[] args) { EncapsulatedVariableInAMethod(); Console.ReadLine(); } } } } From the above example the count integer is encapsulated within EncapsulatedVariableInAMethod method. You couldn’t access the count variable from outside the scope of its parent method but have full access to it within the method. Lets look at my F# equivalent… open System let EncapsulatedVariableInAMethod = let count = 10 Console.WriteLine(count) () EncapsulatedVariableInAMethod Console.ReadLine()   Now, when I first attempted to write the F# code I got stuck… I didn’t have the Console.WriteLine calls but had the following… open System let EncapsulatedVariableInAMethod = let count = 10 EncapsulatedVariableInAMethod Console.ReadLine()   The compiler didn’t like the let before the count = 10. This is because every F# expression must evaluate to a value. If I did not want to make the Console call, I would still need to evaluate the expression to something – and for this reason the Unit Type is provided. I could have done something like…. open System let EncapsulatedVariableInAMethod = let count = 10 () EncapsulatedVariableInAMethod Console.ReadLine()   Which the compiler would be happy with…

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  • Building an E-Commerce Website? 7 Tips For Finding Your Ideal Technology Teacher

    Like many adults, until recently, I'd never contemplated building a website and learning online technology to create an e-business. Still, the growth of the world-wide-web and my location in an area where good-paying jobs are hard to find forced me to re-evaluate whether I could master enough website technology to build a blog and do business online. The one thing I did know was that a good teacher or consultant could make the difference between success and failure.

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  • puppet cert mismatch in ec2

    - by Stick
    I'm setting up a puppetmaster (2.7.6) in ec2 via gems (on rhel6) and I'm running into problems with the cert names and getting the master able to talk to itself. my puppet.conf looks like this: [main] logdir = /var/log/puppet rundir = /var/run/puppet vardir = /var/lib/puppet ssldir = $vardir/ssl pluginsync = true environment = production report = true certname = master When I start the puppetmaster process the ssl directory looks like: ssl/private_keys/master.pem ssl/crl.pem ssl/public_keys/master.pem ssl/ca/ca_crl.pem ssl/ca/signed/master.pem ssl/ca/ca_crt.pem ssl/ca/ca_pub.pem ssl/ca/ca_key.pem ssl/certs/ca.pem ssl/certs/master.pem I have an /etc/hosts entry on the box to point the 'puppet' hostname to localhost so that I don't have to change the 'server' option. When I run the agent I get the following: # puppet agent --test info: Retrieving plugin err: /File[/var/lib/puppet/lib]: Failed to generate additional resources using 'eval_generate: Server hostname 'puppet' did not match server certificate; expected master err: /File[/var/lib/puppet/lib]: Could not evaluate: Server hostname 'puppet' did not match server certificate; expected master Could not retrieve file metadata for puppet://puppet/plugins: Server hostname 'puppet' did not match server certificate; expected master err: Could not retrieve catalog from remote server: Server hostname 'puppet' did not match server certificate; expected master warning: Not using cache on failed catalog err: Could not retrieve catalog; skipping run err: Could not send report: Server hostname 'puppet' did not match server certificate; expected master If I specify the certname as the server (with corresponding hosts entry) I get: # puppet agent --test --server master info: Retrieving plugin err: /File[/var/lib/puppet/lib]: Could not evaluate: Could not retrieve information from environment production source(s) puppet://master/plugins info: Caching catalog for master info: Applying configuration version '1321805956' notice: Finished catalog run in 0.05 seconds Which is success of a sort, that source error will bite me later when I'm applying manifests. I've tried a couple of other variations with using the ec2 private hostname and gotten mixed results. I'd like to avoid setting server = 'x' and use dns/hosts to control what 'puppet' resolves to in order to decide which server (plays easier with availability zones, etc)

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  • PHP/MySQL Performance Testing with Just PHP

    - by Mike Gifford
    I'm trying to diagnose a server where the website is loading very slowly, but unfortunately my client has only provided me with FTP access. I've got FTP access so I can upload PHP scripts, but can't set up any other server side tools. I have access to phpMyAdmin, but not direct access to the MySQL server. It is also unfortunately a Windows server (and we've been a Linux shop for over a decade now). So, if I wan to evaluate MySQL & disk speed performance through PHP on a generic server, what is the best way to do this? There are already tools like: https://github.com/raphaelm/php-benchmark or https://github.com/InfinitySoft/php-benchmark But I'm surprised there isn't something that someone has already set up & configured to just run through and do some basic testing of a server's responsiveness. Every time we evaluate a new server environment it's handy to be able to compare it to an existing one quickly to see if there are any anomalies. I guess I'd just hoped that someone else had written up a script to do this already. I know I have, but that was before Github when there was a handy place to post scraps of code like this. Originally posted in http://stackoverflow.com/questions/12321498/php-mysql-performance-testing-with-just-php but it was recommended that I re-post it here.

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  • ZFS with L2ARC (SSD) slower for random seeks than without L2ARC

    - by Florian Kruse
    I am currently testing ZFS (Opensolaris 2009.06) in an older fileserver to evaluate its use for our needs. Our current setup is as follows: Dual core (2,4 GHz) with 4 GB RAM 3x SATA controller with 11 HDDs (250 GB) and one SSD (OCZ Vertex 2 100 GB) We want to evaluate the use of a L2ARC, so the current ZPOOL is: $ zpool status pool: tank state: ONLINE scrub: none requested config: NAME STATE READ WRITE CKSUM afstank ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c11t0d0 ONLINE 0 0 0 c11t1d0 ONLINE 0 0 0 c11t2d0 ONLINE 0 0 0 c11t3d0 ONLINE 0 0 0 raidz1 ONLINE 0 0 0 c13t0d0 ONLINE 0 0 0 c13t1d0 ONLINE 0 0 0 c13t2d0 ONLINE 0 0 0 c13t3d0 ONLINE 0 0 0 cache c14t3d0 ONLINE 0 0 0 where c14t3d0 is the SSD (of course). We run IO tests with bonnie++ 1.03d, size is set to 200 GB (-s 200g) so that the test sample will never be completely in ARC/L2ARC. The results without SSD are (average values over several runs which show no differences) write_chr write_blk rewrite read_chr read_blk random seeks 101.998 kB/s 214.258 kB/s 96.673 kB/s 77.702 kB/s 254.695 kB/s 900 /s With SSD it becomes interesting. My assumption was that the results should be in worst case at least the same. While write/read/rewrite rates are not different, the random seek rate differs significantly between individual bonnie++ runs (between 188 /s and 1333 /s so far), average is 548 +- 200 /s, so below the value w/o SSD. So, my questions are mainly: Why do the random seek rates differ so much? If the seeks are really random, they should not differ much (my assumption). So, even if the SSD is impairing the performance it should be the same in each bonnie++ run. Why is the random seek performance worse in most of the bonnie++ runs? I would assume that some part of the bonnie++ data is in the L2ARC and random seeks on this data performs better while random seeks on other data just performs similarly like before.

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  • Session Evaluations

    - by BuckWoody
    I do a lot of public speaking. I write, teach, present and communicate at many levels. I love to do those things. And I love to get better at them. And one of the ways you get better at something is to get feedback on how you did. That being said, I have to confess that I really despise the “evaluations” I get at most venues. From college to technical events to other locations, at Microsoft and points in between, I find these things to be just shy of damaging, and most certainly useless. And it’s not always your fault. Ouch. That seems harsh. But let me ask you one question – and be as honest as you can with the answer – think about it first: “What is the point of a session evaluation?” I’m not saying there isn’t one. In fact, I think there’s a really important reason for them. In my mind, it’s really this: To make the speaker / next session better. Now, if you look at that, you can see right away that most session evals don’t accomplish this goal – not even a little. No, the way that they are worded and the way you (and I) fill them out, it’s more like the implied goal is this: Tell us how you liked this speaker / session. The current ones are for you, not for the speaker or the next person. It’s a popularity contest. Don’t get me wrong. I want to you have a good time. I want you to learn. I want (desperately, oh, please oh please) for you to like me. But in fact, that’s probably not why you went to the session / took the class / read that post. No, you want to learn, and to learn for a particular reason. Remember, I’m talking about college classes, sessions and other class environments here, not a general public event. Most – OK, all – session evaluations make you answer the second goal, not the first. Let’s see how: First, they don’t ask you why you’re there. They don’t ask you if you’re even qualified to evaluate the session or speaker. They don’t ask you how to make it better or keep it great. They use odd numeric scales that are meaningless. For instance, can someone really tell me the difference between a 100-level session and a 200-level one? Between a 400-level and a 500? Is it “internals” (whatever that means) or detail, or length or code, or what? I once heard a great description: A 100-level session makes me say, “wow - I’m smart.” A 500-level session makes me say “wow – that presenter is smart.” And just what is the difference between a 6 and a 7 answer on this question: How well did the speaker know the material? 1  2  3  4  5  6  7  8  9  10 Oh. My. Gosh. How does that make the next session better, or the speaker? And what criteria did you use to answer? And is a “10” better than a “1” (not always clear, and various cultures answer this differently). When it’s all said and done, a speaker basically finds out one thing from the current session evals: “They liked me. They really really liked me.” Or, “Wow. I think I may need to schedule some counseling for the depression I’m about to go into.” You may not think that’s what the speaker hears, but trust me, they do. Those are the only two reactions to the current feedback sheets they get. Either they keep doing what they are doing, or they get their feelings hurt. They just can’t use the information provided to do better. Sorry, but there it is. Keep in mind I do want your feedback. I want to get better. I want you to get your money and time’s worth, probably as much as any speaker alive. But I want those evaluations to be accurate, specific and actionable. I want to know if you had a good time, sure, but I also want to know if I did the right things, and if not, if I can do something different or better. And so, for your consideration, here is the evaluation form I would LOVE for you to use. Feel free to copy it and mail it to me any time. I’m going to put some questions here, and then I’ll even include why they are there. Notice that the form asks you a subjective question right away, and then makes you explain why. That’s work on your part. Notice also that it separates the room and the coffee and the lights and the LiveMeeting from the presenter. So many presenters are faced with circumstances beyond their control, and yet are rated high or low personally on those things. This form helps tease those apart. It’s not numeric. Numbers are easier for the scoring committees but are useless for you and me. So I don’t have any numbers. We’re actually going to have to read these things, not put them in a machine. Hey, if you put in the work to write stuff down, the least we could do is take the time to read it. It’s not anonymous. If you’ve got something to say, say it, and own up to it. People are not “more honest” when they are anonymous, they are less honest. So put your name on it. In fact – this is radical – I posit that these evaluations should be publicly available. Forever. Just like replies to a blog post. Hey, if I’m an organizer, I would LOVE to be able to have access to specific, actionable information on the attendees and the speakers. So if you want mine to be public, go for it. I’ll take the good and the bad. Enjoy. ------------------------------------------------------------------------------------------------------------------------------------------- Session Evaluation – Date, Time, Location, Topic Thanks for giving us your time today. We know that’s valuable, and we hope you learned something you can use from the session. If you can answer these questions as completely as you can, it will help the next person who attends a session here. Your Name: What you do for a living: (We Need your background to evaluate your evaluation) How long you have been doing that: (Again, we need your background to evaluate your evaluation) Paste Session Description Here: (This is what I said I would talk about) Did you like the session?                     No        Meh        Yes (General subjective question – overall “feeling”. You’ll tell us why in a minute.)  Tell us about the venue. Temperature, lights, coffee, or the online sound, performance, anything other than the speaker and the material. (Helps the logistics to be better or as good for the next person) 1. What did you expect to learn in this session? (How did you interpret that extract – did you have expectations that I should work towards for the next person?) 2. Did you learn what you expected to learn? Why? Be very specific. (This is the most important question there is. It tells us how to make the session better for someone like you.) 3. If you were giving this presentation, would you have done anything differently? What? (Helps us to gauge you, the listener, and might give us a great idea on how to do something better. Thanks!) 4. What will you do with the information you got? (Every presenter wants you to learn, and learn something useful. This will help us do that as well or better)  

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  • Session Update from IASA 2010

    - by [email protected]
    Below: Tom Kristensen, senior vice president at Marsh US Consumer, and Roger Soppe, CLU, LUTCF, senior director of insurance strategy, Oracle Insurance. Tom and Roger participated in a panel discussion on policy administration systems this week at IASA 2010. This week was the 82nd Annual IASA Educational Conference & Business Show held in Grapevine, Texas. While attending the conference, I had the pleasure of serving as a panelist in one of many of the outstanding sessions conducted this year. The session - entitled "Achieving Business Agility and Promoting Growth with a Modern Policy Administration System" - included industry experts Steve Forte from OneShield, Mike Sciole of IFG Companies, and Tom Kristensen, senior vice president at Marsh US Consumer. The session was conducted as a panel discussion and focused on how insurers can leverage best practices to mitigate risk while enabling rapid product innovation through a modern policy administration system. The panelists offered insight into business and technical challenges for both Life & Annuity and Property & Casualty carriers. The session had three primary learning objectives: Identifying how replacing a legacy system with a more modern policy administration solution can deliver agility and growth Identifying how processes and system should be re-engineered or replaced in order to improve speed-to-market and product support Uncovering how to leverage best practices to mitigate risk during a migration to a new platform Tom Kristensen, who is an industry veteran with over 20 years of experience, was able was able to offer a unique perspective as a business process outsourcer (BPO). Marsh US Consumer is currently implementing both the Oracle Insurance Policy Administration solution and the Oracle Revenue Management and Billing platform while at the same time implementing a new BPO customer. Tom offered insight on the need to replace their aging systems and Marsh's ability to drive new products and processes with a modern solution. As a best practice, their current project has empowered their business users to play a major role in both the requirements gathering and configuration phases. Tom stated that working with a modern solution has also enabled his organization to use a more agile implementation methodology and get hands-on experience with the software earlier in the project. He also indicated that Marsh was encouraged by how quickly it will be able to implement new products, which is another major advantage of a modern rules-based system. One of the more interesting issues was raised by an audience member who asked, "With all the vendor solutions available in North American and across Europe, what is going to make some of them more successful than others and help ensure their long term success?" Panelist Mike Sciole, IFG Companies suggested that carriers do their due diligence and follow a structured evaluation process focusing on vendors who demonstrate they have the "cash to invest in long term R&D" and evaluate audited annual statements for verification. Other panelists suggested that the vendor space will continue to evolve and those with a strong strategy focused on the insurance industry and a solid roadmap will likely separate themselves from the rest. The session concluded with the panelists offering advice about not being afraid to evaluate new modern systems. While migrating to a new platform can be challenging and is typically only undertaken every 15+ years by carriers, the ability to rapidly deploy and manage new products, create consistent processes to better service customers, and the ability to manage their business more effectively, transparently and securely are well worth the effort. Roger A.Soppe, CLU, LUTCF, is the Senior Director of Insurance Strategy, Oracle Insurance.

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  • Validating Petabytes of Data with Regularity and Thoroughness

    - by rickramsey
    by Brian Zents When former Intel CEO Andy Grove said “only the paranoid survive,” he wasn’t necessarily talking about tape storage administrators, but it’s a lesson they’ve learned well. After all, tape storage is the last line of defense to prevent data loss, so tape administrators are extra cautious in making sure their data is secure. Not surprisingly, we are often asked for ways to validate tape media and the files on them. In the past, an administrator could validate the media, but doing so was often tedious or disruptive or both. The debut of the Data Integrity Validation (DIV) and Library Media Validation (LMV) features in the Oracle T10000C drive helped eliminate many of these pains. Also available with the Oracle T10000D drive, these features use hardware-assisted CRC checks that not only ensure the data is written correctly the first time, but also do so much more efficiently. Traditionally, a CRC check takes at least 25 seconds per 4GB file with a 2:1 compression ratio, but the T10000C/D drives can reduce the check to a maximum of nine seconds because the entire check is contained within the drive. No data needs to be sent to a host application. A time savings of at least 64 percent is extremely beneficial over the course of checking an entire 8.5TB T10000D tape. While the DIV and LMV features are better than anything else out there, what storage administrators really need is a way to check petabytes of data with regularity and thoroughness. With the launch of Oracle StorageTek Tape Analytics (STA) 2.0 in April, there is finally a solution that addresses this longstanding need. STA bundles these features into one interface to automate all media validation activities across all Oracle SL3000 and SL8500 tape libraries in an environment. And best of all, the validation process can be associated with the health checks an administrator would be doing already through STA. In fact, STA validates the media based on any of the following policies: Random Selection – Randomly selects media for validation whenever a validation drive in the standalone library or library complex is available. Media Health = Action – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Action.” You can specify from one to five exchanges. Media Health = Evaluate – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Evaluate.” You can specify from one to five exchanges. Media Health = Monitor – Selects media that have had a specified number of successive exchanges resulting in an Exchange Media Health of “Monitor.” You can specify from one to five exchanges. Extended Period of Non-Use – Selects media that have not had an exchange for a specified number of days. You can specify from 365 to 1,095 days (one to three years). Newly Entered – Selects media that have recently been entered into the library. Bad MIR Detected – Selects media with an exchange resulting in a “Bad MIR Detected” error. A bad media information record (MIR) indicates degraded high-speed access on the media. To avoid disrupting host operations, an administrator designates certain drives for media validation operations. If a host requests a file from media currently being validated, the host’s request takes priority. To ensure that the administrator really knows it is the media that is bad, as opposed to the drive, STA includes drive calibration and qualification features. In addition, validation requests can be re-prioritized or cancelled as needed. To ensure that a specific tape isn’t validated too often, STA prevents a tape from being validated twice within 24 hours via one of the policies described above. A tape can be validated more often if the administrator manually initiates the validation. When the validations are complete, STA reports the results. STA does not report simply a “good” or “bad” status. It also reports if media is even degraded so the administrator can migrate the data before there is a true failure. From that point, the administrators’ paranoia is relieved, as they have the necessary information to make a sound decision about the health of the tapes in their environment. About the Photograph Photograph taken by Rick Ramsey in Death Valley, California, May 2014 - Brian Follow OTN Garage on: Web | Facebook | Twitter | YouTube

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  • How can we improve overall Programmer Education & Training?

    - by crosenblum
    Last week, I was just viewing this amazing interview by Kevin Rose of Phillip Rosedale, of Second Life. And they had an amazing discussion about how to find, hire and identify good programmer's, and how hard it is to find good ones. Which has lead me to really think about the way we programmer's learn, are taught. For a majority of us, myself included, we are self-taught. Which is great about being a programmer, anyone can learn and develop skills. But this also means, that there is no real standards of what a good programmer is/are, and what kind of environment's encourage the growth of programming skills. This isn't so much a question, but just a desire in me, to see how we can change the culture of programming, and the manager's of programming, so that education and self-improvement is encouraged. There are a lot of avenue's for continued education, youtube videos, books, conferences, but because of the experiental nature of what we do, it isn't always clear what's important to learn and to master. Let's look at the The Joel 12 Steps. The Joel Test Do you use source control? Can you make a build in one step? Do you make daily builds? Do you have a bug database? Do you fix bugs before writing new code? Do you have an up-to-date schedule? Do you have a spec? Do programmers have quiet working conditions? Do you use the best tools money can buy? Do you have testers? Do new candidates write code during their interview? Do you do hallway usability testing? I think all of these have important value, but because of something I call the Experiential Gap, if a programmer or manager has never experienced any of the negative consequences for not having done items on the list, they will never see the need to do any of them. The Experiental Gap, is my basic theory, that each of us has different jobs and different experiences. So for some of us, that have always worked with dozens of programmer's, source control is a must have. But for people who have always been the only programmer, they can not imagine the need for source control. And it's because of this major flaw in how we learn, that we evaluate people by what best practices they do or not do, and the reason for either can start a flame war. We always evaluate people in our field by what they do, and think "Oh if this guy/gal isn't doing xyz best practice, he/she can't be a good programmer, so let's not waste time or energy talking to them." This is exactly why we have so many programming flame wars, that it becomes, because of the Experiental Gap, we can't imagine people not having made the decisions that we have had to made. So this has lead me to think, that we totally need to rethink how we train, educate and manage programmer's. For example, what percentage of you have had encouragement by your manager's to go to conferences, and even have them pay for it? For me, and a lot of people, this is extremely rare, a lot of us would love to go to conferences, to learn more, but the money ain't there to do that. So the point of this question is really to spark a lot of how can we train, learn and manage better? How can we create a new culture of learning that doesn't insult people for not having the same job experiences. Yes we all have jobs and work to do, but our ability to do our jobs well, depends on our desire, interest and support in improving our mastery of our skills. Right now, I see our culture being rather disorganized, we support the elite, but those tons of us that want to get better, just don't have enough support to learn and improve ourselves. I mean, do we as an industry, want to be perceived as just replaceable cogs? Thank you...

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  • Why is x=x++ undefined?

    - by ugoren
    It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

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  • Appropriate design / technologies to handle dynamic string formatting?

    - by Mark W
    recently I was tasked with implementing a way of adding support for versioning of hardware packet specifications to one of our libraries. First a bit of information about the project. We have a hardware library which has classes for each of the various commands we support sending to our hardware. These hardware modules are essentially just lights with a few buttons, and a 2 or 4 digit display. The packets typically follow the format {SOH}AADD{ETX}, where AA is our sentinel action code, and DD is the device ID. These packet specs are different from one command to the next obviously, and the different firmware versions we have support different specifications. For example, on version 1 an action code of 14 may have a spec of {SOH}AADDTEXT{ETX} which would be AA = 14 literal, DD = device ID, TEXT = literal text to display on the device. Then we come out with a revision with adds an extended byte(s) onto the end of the packet like this {SOH}AADDTEXTE{ETX}. Assume the TEXT field is fixed width for this example. We have now added a new field onto the end which could be used to say specify the color or flash rate of the text/buttons. Currently this java library only supports one version of the commands, the latest. In our hardware library we would have a class for this command, say a DisplayTextArgs.java. That class would have fields for the device ID, the text, and the extended byte. The command class would expose a method which generates the string ("{SOH}AADDTEXTE{ETX}") using the value from the class. In practice we would create the Args class as needed, populate the fields, call the method to get our packet string, then ship that down across the CAN. Some of our other commands specification can vary for the same command, on the same version, depending on some runtime state. For example, another command for version 1 may be {SOH}AA{ETX}, where this action code clears all of the modules behind a specific controller device of their text. We may overload this packet to have option fields with multiple meanings like {SOH}AAOC{ETX} where OC is literal text, which tells the controller to only clear text on a specific module type, and to leave the others alone, or the spec could also have an option format of {SOH}AADD{ETX} to clear the text off a a specific device. Currently, in the method which generates the packet string, we would evaluate fields on the args class to determine which spec we will be using when formatting the packet. For this example, it would be along the lines of: if m_DeviceID != null then use {SOH}AADD{ETX} else if m_ClearOCs == true then use {SOH}AAOC{EXT} else use {SOH}AA{ETX} I had considered using XML, or a database to store String.format format strings, which were linked to firmware version numbers in some table. We would load them up at startup, and pass in the version number of the hardwares firmware we are currently using (I can query the devices for their firmware version, but the version is not included in all packets as part of the spec). This breaks down pretty quickly because of the dynamic nature of how we select which version of the command to use. I then considered using a rule engine to possibly build out expressions which could be interpreted at runtume, to evaluate the args class's state, and from that select the appropriate format string to use, but my brief look at rule engines for java scared me away with its complexity. While it seems like it might be a viable solution, it seems overly complex. So this is why I am here. I wouldn't say design is my strongest skill, and im having trouble figuring out the best way to approach this problem. I probably wont be able to radically change the args classes, but if the trade off was good enough, I may be able to convince my boss that the change is appropriate. What I would like from the community is some feedback on some best practices / design methodologies / API or other resources which I could use to accomplish: Logic to determine which set of commands to use for a given firmware version Of those command, which version of each command to use (based on the args classes state) Keep the rules logic decoupled from the application so as to avoid needing releases for every firmware version Be simple enough so I don't need weeks of study and trial and error to implement effectively.

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  • Why is 0 false?

    - by Morwenn
    This question may sound dumb, but why does 0 evaluates to false and any other [integer] value to true is most of programming languages? String comparison Since the question seems a little bit too simple, I will explain myself a little bit more: first of all, it may seem evident to any programmer, but why wouldn't there be a programming language - there may actually be, but not any I used - where 0 evaluates to true and all the other [integer] values to false? That one remark may seem random, but I have a few examples where it may have been a good idea. First of all, let's take the example of strings three-way comparison, I will take C's strcmp as example: any programmer trying C as his first language may be tempted to write the following code: if (strcmp(str1, str2)) { // Do something... } Since strcmp returns 0 which evaluates to false when the strings are equal, what the beginning programmer tried to do fails miserably and he generally does not understand why at first. Had 0 evaluated to true instead, this function could have been used in its most simple expression - the one above - when comparing for equality, and the proper checks for -1 and 1 would have been done only when needed. We would have considered the return type as bool (in our minds I mean) most of the time. Moreover, let's introduce a new type, sign, that just takes values -1, 0 and 1. That can be pretty handy. Imagine there is a spaceship operator in C++ and we want it for std::string (well, there already is the compare function, but spaceship operator is more fun). The declaration would currently be the following one: sign operator<=>(const std::string& lhs, const std::string& rhs); Had 0 been evaluated to true, the spaceship operator wouldn't even exist, and we could have declared operator== that way: sign operator==(const std::string& lhs, const std::string& rhs); This operator== would have handled three-way comparison at once, and could still be used to perform the following check while still being able to check which string is lexicographically superior to the other when needed: if (str1 == str2) { // Do something... } Old errors handling We now have exceptions, so this part only applies to the old languages where no such thing exist (C for example). If we look at C's standard library (and POSIX one too), we can see for sure that maaaaany functions return 0 when successful and any integer otherwise. I have sadly seen some people do this kind of things: #define TRUE 0 // ... if (some_function() == TRUE) { // Here, TRUE would mean success... // Do something } If we think about how we think in programming, we often have the following reasoning pattern: Do something Did it work? Yes -> That's ok, one case to handle No -> Why? Many cases to handle If we think about it again, it would have made sense to put the only neutral value, 0, to yes (and that's how C's functions work), while all the other values can be there to solve the many cases of the no. However, in all the programming languages I know (except maybe some experimental esotheric languages), that yes evaluates to false in an if condition, while all the no cases evaluate to true. There are many situations when "it works" represents one case while "it does not work" represents many probable causes. If we think about it that way, having 0 evaluate to true and the rest to false would have made much more sense. Conclusion My conclusion is essentially my original question: why did we design languages where 0 is false and the other values are true, taking in account my few examples above and maybe some more I did not think of? Follow-up: It's nice to see there are many answers with many ideas and as many possible reasons for it to be like that. I love how passionate you seem to be about it. I originaly asked this question out of boredom, but since you seem so passionate, I decided to go a little further and ask about the rationale behind the Boolean choice for 0 and 1 on Math.SE :)

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  • Efficient Multiple Linear Regression in C# / .Net

    - by mrnye
    Does anyone know of an efficient way to do multiple linear regression in C#, where the number of simultaneous equations may be in the 1000's (with 3 or 4 different inputs). After reading this article on multiple linear regression I tried implementing it with a matrix equation: Matrix y = new Matrix( new double[,]{{745}, {895}, {442}, {440}, {1598}}); Matrix x = new Matrix( new double[,]{{1, 36, 66}, {1, 37, 68}, {1, 47, 64}, {1, 32, 53}, {1, 1, 101}}); Matrix b = (x.Transpose() * x).Inverse() * x.Transpose() * y; for (int i = 0; i < b.Rows; i++) { Trace.WriteLine("INFO: " + b[i, 0].ToDouble()); } However it does not scale well to the scale of 1000's of equations due to the matrix inversion operation. I can call the R language and use that, however I was hoping there would be a pure .Net solution which will scale to these large sets. Any suggestions? EDIT #1: I have settled using R for the time being. By using statconn (downloaded here) I have found it to be both fast & relatively easy to use this method. I.e. here is a small code snippet, it really isn't much code at all to use the R statconn library (note: this is not all the code!). _StatConn.EvaluateNoReturn(string.Format("output <- lm({0})", equation)); object intercept = _StatConn.Evaluate("coefficients(output)['(Intercept)']"); parameters[0] = (double)intercept; for (int i = 0; i < xColCount; i++) { object parameter = _StatConn.Evaluate(string.Format("coefficients(output)['x{0}']", i)); parameters[i + 1] = (double)parameter; }

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  • Looking for ideas how to refactor my (complex) algorithm

    - by _simon_
    I am trying to write my own Game of Life, with my own set of rules. First 'concept', which I would like to apply, is socialization (which basicaly means if the cell wants to be alone or in a group with other cells). Data structure is 2-dimensional array (for now). In order to be able to move a cell to/away from a group of another cells, I need to determine where to move it. The idea is, that I evaluate all the cells in the area (neighbours) and get a vector, which tells me where to move the cell. Size of the vector is 0 or 1 (don't move or move) and the angle is array of directions (up, down, right, left). This is a image with representation of forces to a cell, like I imagined it (but reach could be more than 5): Let's for example take this picture: Forces from lower left neighbour: down (0), up (2), right (2), left (0) Forces from right neighbour : down (0), up (0), right (0), left (2) sum : down (0), up (2), right (0), left (0) So the cell should go up. I could write an algorithm with a lot of if statements and check all cells in the neighbourhood. Of course this algorithm would be easiest if the 'reach' parameter is set to 1 (first column on picture 1). But what if I change reach parameter to 10 for example? I would need to write an algorithm for each 'reach' parameter in advance... How can I avoid this (notice, that the force is growing potentialy (1, 2, 4, 8, 16, 32,...))? Can I use specific design pattern for this problem? Also: the most important thing is not speed, but to be able to extend initial logic. Things to take into consideration: reach should be passed as a parameter i would like to change function, which calculates force (potential, fibonacci) a cell can go to a new place only if this new place is not populated watch for corners (you can't evaluate right and top neighbours in top-right corner for example)

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  • Beginner problems with references to arrays in python 3.1.1

    - by Protean
    As part of the last assignment in a beginner python programing class, I have been assigned a traveling sales man problem. I settled on a recursive function to find each permutation and the sum of the distances between the destinations, however, I am have a lot of problems with references. Arrays in different instances of the Permute and Main functions of TSP seem to be pointing to the same reference. from math import sqrt class TSP: def __init__(self): self.CartisianCoordinates = [['A',[1,1]], ['B',[2,2]], ['C',[2,1]], ['D',[1,2]], ['E',[3,3]]] self.Array = [] self.Max = 0 self.StoredList = ['',0] def Distance(self, i1, i2): x1 = self.CartisianCoordinates[i1][1][0] y1 = self.CartisianCoordinates[i1][1][1] x2 = self.CartisianCoordinates[i2][1][0] y2 = self.CartisianCoordinates[i2][1][1] return sqrt(pow((x2 - x1), 2) + pow((y2 - y1), 2)) def Evaluate(self): temparray = [] Data = [] for i in range(len(self.CartisianCoordinates)): Data.append([]) for i1 in range(len(self.CartisianCoordinates)): for i2 in range(len(self.CartisianCoordinates)): if i1 != i2: temparray.append(self.Distance(i1, i2)) else: temparray.append('X') Data[i1] = temparray temparray = [] self.Array = Data self.Max = len(Data) def Permute(self,varray,index,vcarry,mcarry): #Problem Class array = varray[:] carry = vcarry[:] for i in range(self.Max): print ('ARRAY:', array) print (index,i,carry,array[index][i]) if array[index][i] != 'X': carry[0] += self.CartisianCoordinates[i][0] carry[1] += array[index][i] if len(carry) != self.Max: temparray = array[:] for j in range(self.Max):temparray[j][i] = 'X' index = i mcarry += self.Permute(temparray,index,carry,mcarry) else: return mcarry print ('pass',mcarry) return mcarry def Main(self): out = [] self.Evaluate() for i in range(self.Max): array = self.Array[:] #array appears to maintain the same reference after each copy, resulting in an incorrect array being passed to Permute after the first iteration. print (self.Array[:]) for j in range(self.Max):array[j][i] = 'X' print('I:', i, array) out.append(self.Permute(array,i,[str(self.CartisianCoordinates[i][0]),0],[])) return out SalesPerson = TSP() print(SalesPerson.Main()) It would be greatly appreciated if you could provide me with help in solving the reference problems I am having. Thank you.

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  • Test-Driven Development Problem

    - by Zeck
    Hi guys, I'm newbie to Java EE 6 and i'm trying to develop very simple JAX-RS application. RESTfull web service working fine. However when I ran my test application, I got the following. What have I done wrong? Or am i forget any configuration? Of course i'm create a JNDI and i'm using Netbeans 6.8 IDE. In finally, thank you for any advise. My Entity: @Entity @Table(name = "BOOK") @NamedQueries({ @NamedQuery(name = "Book.findAll", query = "SELECT b FROM Book b"), @NamedQuery(name = "Book.findById", query = "SELECT b FROM Book b WHERE b.id = :id"), @NamedQuery(name = "Book.findByTitle", query = "SELECT b FROM Book b WHERE b.title = :title"), @NamedQuery(name = "Book.findByDescription", query = "SELECT b FROM Book b WHERE b.description = :description"), @NamedQuery(name = "Book.findByPrice", query = "SELECT b FROM Book b WHERE b.price = :price"), @NamedQuery(name = "Book.findByNumberofpage", query = "SELECT b FROM Book b WHERE b.numberofpage = :numberofpage")}) public class Book implements Serializable { private static final long serialVersionUID = 1L; @Id @Basic(optional = false) @Column(name = "ID") private Integer id; @Basic(optional = false) @Column(name = "TITLE") private String title; @Basic(optional = false) @Column(name = "DESCRIPTION") private String description; @Basic(optional = false) @Column(name = "PRICE") private double price; @Basic(optional = false) @Column(name = "NUMBEROFPAGE") private int numberofpage; public Book() { } public Book(Integer id) { this.id = id; } public Book(Integer id, String title, String description, double price, int numberofpage) { this.id = id; this.title = title; this.description = description; this.price = price; this.numberofpage = numberofpage; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public int getNumberofpage() { return numberofpage; } public void setNumberofpage(int numberofpage) { this.numberofpage = numberofpage; } @Override public int hashCode() { int hash = 0; hash += (id != null ? id.hashCode() : 0); return hash; } @Override public boolean equals(Object object) { // TODO: Warning - this method won't work in the case the id fields are not set if (!(object instanceof Book)) { return false; } Book other = (Book) object; if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) { return false; } return true; } @Override public String toString() { return "com.entity.Book[id=" + id + "]"; } } My Junit test class: public class BookTest { private static EntityManager em; private static EntityManagerFactory emf; public BookTest() { } @BeforeClass public static void setUpClass() throws Exception { emf = Persistence.createEntityManagerFactory("E01R01PU"); em = emf.createEntityManager(); } @AfterClass public static void tearDownClass() throws Exception { em.close(); emf.close(); } @Test public void createBook() { Book book = new Book(); book.setId(1); book.setDescription("Mastering the Behavior Driven Development with Ruby on Rails"); book.setTitle("Mastering the BDD"); book.setPrice(25.9f); book.setNumberofpage(1029); em.persist(book); assertNotNull("ID should not be null", book.getId()); } } My persistence.xml jta-data-sourceBookstoreJNDI And exception is: May 7, 2009 11:10:37 AM org.hibernate.validator.util.Version INFO: Hibernate Validator bean-validator-3.0-JBoss-4.0.2 May 7, 2009 11:10:37 AM org.hibernate.validator.engine.resolver.DefaultTraversableResolver detectJPA INFO: Instantiated an instance of org.hibernate.validator.engine.resolver.JPATraversableResolver. [EL Info]: 2009-05-07 11:10:37.531--ServerSession(13671123)--EclipseLink, version: Eclipse Persistence Services - 2.0.0.v20091127-r5931 May 7, 2009 11:10:40 AM com.sun.enterprise.transaction.JavaEETransactionManagerSimplified initDelegates INFO: Using com.sun.enterprise.transaction.jts.JavaEETransactionManagerJTSDelegate as the delegate May 7, 2009 11:10:43 AM com.sun.enterprise.connectors.ActiveRAFactory createActiveResourceAdapter SEVERE: rardeployment.class_not_found May 7, 2009 11:10:43 AM com.sun.enterprise.connectors.ActiveRAFactory createActiveResourceAdapter SEVERE: com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR at com.sun.enterprise.connectors.ActiveRAFactory.createActiveResourceAdapter(ActiveRAFactory.java:104) at com.sun.enterprise.connectors.service.ResourceAdapterAdminServiceImpl.createActiveResourceAdapter(ResourceAdapterAdminServiceImpl.java:216) at com.sun.enterprise.connectors.ConnectorRuntime.createActiveResourceAdapter(ConnectorRuntime.java:352) at com.sun.enterprise.resource.naming.ConnectorObjectFactory.getObjectInstance(ConnectorObjectFactory.java:106) at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304) at com.sun.enterprise.naming.impl.SerialContext.getObjectInstance(SerialContext.java:472) at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:437) at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:569) at javax.naming.InitialContext.lookup(InitialContext.java:396) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:110) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:94) at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162) at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228) at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:368) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195) at com.entity.BookTest.setUpClass(BookTest.java:31) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.junit.runners.ParentRunner.run(ParentRunner.java:220) at junit.framework.JUnit4TestAdapter.run(JUnit4TestAdapter.java:39) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:515) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:1031) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:888) Caused by: java.lang.ClassNotFoundException: com.sun.gjc.spi.ResourceAdapter at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at com.sun.enterprise.connectors.ActiveRAFactory.createActiveResourceAdapter(ActiveRAFactory.java:96) ... 32 more [EL Severe]: 2009-05-07 11:10:43.937--ServerSession(13671123)--Local Exception Stack: Exception [EclipseLink-7060] (Eclipse Persistence Services - 2.0.0.v20091127-r5931): org.eclipse.persistence.exceptions.ValidationException Exception Description: Cannot acquire data source [BookstoreJNDI]. Internal Exception: javax.naming.NamingException: Lookup failed for 'BookstoreJNDI' in SerialContext ,orb'sInitialHost=localhost,orb'sInitialPort=3700 [Root exception is javax.naming.NamingException: Failed to look up ConnectorDescriptor from JNDI [Root exception is com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR]] at org.eclipse.persistence.exceptions.ValidationException.cannotAcquireDataSource(ValidationException.java:451) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:116) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:94) at org.eclipse.persistence.sessions.DatasourceLogin.connectToDatasource(DatasourceLogin.java:162) at org.eclipse.persistence.internal.sessions.DatabaseSessionImpl.loginAndDetectDatasource(DatabaseSessionImpl.java:584) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryProvider.login(EntityManagerFactoryProvider.java:228) at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:368) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.getServerSession(EntityManagerFactoryImpl.java:151) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:207) at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:195) at com.entity.BookTest.setUpClass(BookTest.java:31) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.junit.runners.ParentRunner.run(ParentRunner.java:220) at junit.framework.JUnit4TestAdapter.run(JUnit4TestAdapter.java:39) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.run(JUnitTestRunner.java:515) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.launch(JUnitTestRunner.java:1031) at org.apache.tools.ant.taskdefs.optional.junit.JUnitTestRunner.main(JUnitTestRunner.java:888) Caused by: javax.naming.NamingException: Lookup failed for 'BookstoreJNDI' in SerialContext ,orb'sInitialHost=localhost,orb'sInitialPort=3700 [Root exception is javax.naming.NamingException: Failed to look up ConnectorDescriptor from JNDI [Root exception is com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR]] at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:442) at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:569) at javax.naming.InitialContext.lookup(InitialContext.java:396) at org.eclipse.persistence.sessions.JNDIConnector.connect(JNDIConnector.java:110) ... 23 more Caused by: javax.naming.NamingException: Failed to look up ConnectorDescriptor from JNDI [Root exception is com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR] at com.sun.enterprise.resource.naming.ConnectorObjectFactory.getObjectInstance(ConnectorObjectFactory.java:109) at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304) at com.sun.enterprise.naming.impl.SerialContext.getObjectInstance(SerialContext.java:472) at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:437) ... 26 more Caused by: com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR at com.sun.enterprise.connectors.ActiveRAFactory.createActiveResourceAdapter(ActiveRAFactory.java:104) at com.sun.enterprise.connectors.service.ResourceAdapterAdminServiceImpl.createActiveResourceAdapter(ResourceAdapterAdminServiceImpl.java:216) at com.sun.enterprise.connectors.ConnectorRuntime.createActiveResourceAdapter(ConnectorRuntime.java:352) at com.sun.enterprise.resource.naming.ConnectorObjectFactory.getObjectInstance(ConnectorObjectFactory.java:106) ... 29 more Caused by: java.lang.ClassNotFoundException: com.sun.gjc.spi.ResourceAdapter at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:276) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at com.sun.enterprise.connectors.ActiveRAFactory.createActiveResourceAdapter(ActiveRAFactory.java:96) ... 32 more Exception Description: Cannot acquire data source [BookstoreJNDI]. Internal Exception: javax.naming.NamingException: Lookup failed for 'BookstoreJNDI' in SerialContext ,orb'sInitialHost=localhost,orb'sInitialPort=3700 [Root exception is javax.naming.NamingException: Failed to look up ConnectorDescriptor from JNDI [Root exception is com.sun.appserv.connectors.internal.api.ConnectorRuntimeException: Error in creating active RAR]])

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  • Design suggestion for expression tree evaluation with time-series data

    - by Lirik
    I have a (C#) genetic program that uses financial time-series data and it's currently working but I want to re-design the architecture to be more robust. My main goals are: sequentially present the time-series data to the expression trees. allow expression trees to access previous data rows when needed. to optimize performance of the data access while evaluating the expression trees. keep a common interface so various types of data can be used. Here are the possible approaches I've thought about: I can evaluate the expression tree by passing in a data row into the root node and let each child node use the same data row. I can evaluate the expression tree by passing in the data row index and letting each node get the data row from a shared DataSet (currently I'm passing the row index and going to multiple synchronized arrays to get the data). Hybrid: an immutable data set is accessible by all of the expression trees and each expression tree is evaluated by passing in a data row. The benefit of the first approach is that the data row is being passed into the expression tree and there is no further query done on the data set (which should increase performance in a multithreaded environment). The drawback is that the expression tree does not have access to the rest of the data (in case some of the functions need to do calculations using previous data rows). The benefit of the second approach is that the expression trees can access any data up to the latest data row, but unless I specify what that row is, I'll have to iterate through the rows and figure out which one is the last one. The benefit of the hybrid is that it should generally perform better and still provide access to the earlier data. It supports two basic "views" of data: the latest row and the previous rows. Do you guys know of any design patterns or do you have any tips that can help me build this type of system? Should I use a DataSet to hold and present the data, or are there more efficient ways to present rows of data while maintaining a simple interface? FYI: All of my code is written in C#.

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  • ImageMagick Reflection

    - by dbruns
    Brief: convert ( -size 585x128 gradient: ) NewImage.png How do I change the above ImageMagick command so it takes the width and height from an existing image? I need it to remain a one line command. Details: I'm trying to programatically create an image reflection using ImageMagick. The effect I am looking for is similar to what you would see when looking at an object on the edge of a pool of water. There is a pretty good thread on what I am trying to do here but the solution isn't exactly what I am looking for. Since I will be calling ImageMagick from a C#.Net application I want to use one call without any temp files and return the image through stdout. So far I have this... convert OriginalImage.png ( OriginalImage.png -flip -blur 3x5 \ -crop 100%%x30%%+0+0 -negate -evaluate multiply 0.3 \ -negate ( -size 585x128 gradient: ) +matte -compose copy_opacity -composite ) -append NewImage.png This works ok but doesn't give me the exact fade I am looking for. Instead of a nice solid fade from top to bottom it is giving me a fade from top left to bottom right. I added the (-negate -evaluate multiply 0.3 -negate) section in to lighten it up a bit more since I wasn't getting the fade I wanted. I also don't want to have to hard code in the size of the image when creating the gradient ( -size 585x128 gradient: ) I'm also going to want to keep the original image's transparency if possible. To go to stdout I plan on replacing "NewImage.png" with "-"

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  • Xpath: Selecting all of an element type?

    - by Johannes
    I'm just starting to learn Xpath, I'm trying to write a line of code that will select all of the actors in EACH movie parent (through Java!). Below, I have an example of one movie, but there are multiple <Movie> elements, each with <Actor> elements. <Movie Genre = 'Other'> <Title>Requiem For A Dream</Title> <ReleaseYear>2000</ReleaseYear> <Director>Darren Aronofsky</Director> <Actor Character = 'Sara Goldfarb'>Ellen Burstyn</Actor> <Actor Character = 'Harry Goldfarb'>Jared Leto</Actor> <Actor Character = 'Marion Silver'>Jennifer Connelly</Actor> <Actor Character = 'Tyrone C. Love'>Marlon Wayans</Actor> </Movie> Currently, I can only select the first <Actor> element of each <Movie> element -- is it possible to select all of them without using a for loop? Here is my current line of code that displays the first <Actor> element of every <Movie> element: System.out.println("Starring: " + xpath.evaluate("Actor", movieNode) + " as " + xpath.evaluate("Actor/@Character", movieNode) + "\n"); Any and all help if much appreciated!

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  • Use Hudson Build Parameter in Grails Build Target

    - by Stephen Swensen
    I have created two Hudson String Parameters in my parametrized build configuration: svnRoot, and svnBranch. I can reference these just fine when specifying my Repository URL: ${svnRoot}/${svnBranch}/subProject. But I have not been able to reference them as part of my Grails Build Target: "build-applet ${svnRoot}/${svnBranch}/appletProject username password" "war --non-interactive". build-applet invokes a Gant script in the Grails project at scripts\BuildApplet.groovy. This attempt yields the following error: groovy.lang.MissingPropertyException: No such property: svnRoot for class: Script1 at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:49) at org.codehaus.groovy.runtime.callsite.PogoGetPropertySite.getProperty(PogoGetPropertySite.java:49) at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGroovyObjectGetProperty(AbstractCallSite.java:240) at Script1.run(Script1.groovy:1) at groovy.lang.GroovyShell.evaluate(GroovyShell.java:561) at groovy.lang.GroovyShell.evaluate(GroovyShell.java:536) at com.g2one.hudson.grails.GrailsBuilder.evalTarget(GrailsBuilder.java:212) at com.g2one.hudson.grails.GrailsBuilder.perform(GrailsBuilder.java:168) at hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:19) at hudson.model.AbstractBuild$AbstractRunner.perform(AbstractBuild.java:603) at hudson.model.Build$RunnerImpl.build(Build.java:172) at hudson.model.Build$RunnerImpl.doRun(Build.java:137) at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:417) at hudson.model.Run.run(Run.java:1337) at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:46) at hudson.model.ResourceController.execute(ResourceController.java:88) at hudson.model.Executor.run(Executor.java:140) What is the best and or easiest way to achieve my goal?

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  • Is there a way to make changes to toggles in my .emacs file apply without re-starting Emacs?

    - by Vivi
    I want to be able to make the changes to my .emacs file without having to reload Emacs. I found three questions which sort of answer what I am asking (you can find them here, here and here), but the problem is that the change I have just made is to a toggle, and as the comments to two of the answers (a1, a2) to those questions explain, the solutions given there (such as M-x reload-file or M-x eval-buffer) don't apply to toggles. I imagine there is a way of toggling the variable again with a command, but if there is a way to reload the whole .emacs and have the all the toggles re-evaluated without having to specify them, I would prefer. In any case, I would also appreciate if someone told me how to toggle the value of a variable so that if I just changed one toggle I can do it with a command rather than re-start Emacs just for that (I am new to Emacs). I don't know how useful this information is, but the change I applied was the following (which I got from this answer to another question): (setq skeleton-pair t) (setq skeleton-pair-on-word t) (global-set-key (kbd "[") 'skeleton-pair-insert-maybe) (global-set-key (kbd "(") 'skeleton-pair-insert-maybe) (global-set-key (kbd "{") 'skeleton-pair-insert-maybe) (global-set-key (kbd "<") 'skeleton-pair-insert-maybe) Edit: I included the above in .emacs and reloaded Emacs, so that the changes took effect. Then I commented all of it out and tried M-x load-file. This doesn't work. The suggestion below (C-x C-e by PP works if I am using it to evaluate the toggle first time, but not when I want to undo it). I would like something that would evaluate the commenting out, if such thing exists... Thanks :)

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  • can I disable the "(Type e to repeat macro)" message in emacs?

    - by lindes
    Hi there, So, I've finally made the plunge, and have gotten to the state where I'm quite happy to have switched from vi and vim to emacs... I've been putting stuff in my .emacs file, learning how to evaluate things (not to mention becoming familiar with movement commands), etc. etc. etc. And now I have a problem with a require line in my .emacs file (a require statement*), which bombs out when I launch emacs (and generally fails to work). So, this lead me to the following situation: In the process of trying to debug the above situation, one of the steps I did was to open the file I was trying to require, and evaluate it bit by bit, using C-M-f and C-x C-e (and later just M-x eval-buffer), which all worked fine. But along the way of the section-by-section, I got tired of typing all those, and so I recorded a keyboard macro... C-x ( C-M-f C-x C-e C-x ) and then C-x e... which gave me a message in the minibuffer (I think I'm using the right name), saying (Type e to repeat macro). Which meant I could no longer see the resultant value of the evaluation of each section of code... which, while not critical in this case, I was liking having. Which leads me to the actual question: Is there a way to disable that message, and/or to cause the minibuffer to show multiple lines at once? I know about the *Messages* buffer, and that could have helped, I'm just wondering if there's a way to either disable that message, or otherwise make it coexist with other messages. Any suggestions? Thanks! lindes * - the problem at hand, which is not really my question, is that (require 'ruby-mode/ruby-mode) fails, even though emacs is definitely and successfully (per system call tracing) opening and reading the ruby-mode.el file. I presume this is because the provide line says just 'ruby-mode. I've found a solution for this, but if anyone can point me to any "best practices", I'd appreciate it.

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