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• SOA & BPM Best of Oracle OpenWorld 2011

  - by JuergenKress

  Oracle OpenWorld 2011 is over – what important updates did you miss? Keynotes: Best of Oracle OpenWorld keynotes and general session is available on-demand: " + __flash__argumentsToXML(arguments,0) + "")); }' s_getswfurl='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getcharset='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getversion='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getmovieid='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getpageurl='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getpagename='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getaccount='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_gettrackclickmap='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' s_getdomindex='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' onomnitureunload='function () { return eval(instance.CallFunction("" + __flash__argumentsToXML(arguments,0) + "")); }' We recommend to watch: Oracle Cloud Computing Larry Ellison, CEO, Oracle Watch full-length keynote   Middleware General Session Hasan Rizvi, SVP, Oracle Watch full-length general session Presentations: All presentations are available online at the OpenWorld Content Catalog Product highlight: Was to launch of BPM Suite 11.1.1.5 Feature Pack Released and the Oracle Process Accelerators. For details please visit the Oracle BPM team blog and the Oracle SOA team blog.

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• Python script won't write data when ran from cron

  - by Ruud

  When I run a python script in a terminal it runs as expected; downloads file and saves it in the desired spot. sudo python script.py I've added the python script to the root crontab, but then it runs as it is supposed to except it does not write the file. $ sudo crontab -l > * * * * * python /home/test/script.py >> /var/log/test.log 2>&1 Below is a simplified script that still has the problem: #!/usr/bin/python scheduleUrl = 'http://test.com/schedule.xml' schedule = '/var/test/schedule.xml' # Download url and save as filename def wget(url, filename): import urllib2 try: response = urllib2.urlopen(url) except Exception: import traceback logging.exception('generic exception: ' + traceback.format_exc()) else: print('writing:'+filename+';') output = open(filename,'wb') output.write(response.read()) output.close() # Download the schedule wget(scheduleUrl, schedule) I do get the message "writing:name of file;" inside the log, to which the cron entry outputs. But the actual file is nowhere to be found... The dir /var/test is chmodded to 777 and using whatever user, I am allowed to add and change files as I please.

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• Is there an alternative to Google Code Search?

  - by blunders

  Per the Official Google Blog: Code Search, which was designed to help people search for open source code all over the web, will be shut down along with the Code Search API on January 15, 2012. Google Code Search is now gone, and since that makes it much harder to understand the features it presented, here's my attempt to render them via information I gathered from a cache of the page for the Search Options: The "In Search Box" just notes the syntax to type the command directly in the main search box instead of using the advance search interface. Package (In Search Box: "package:linux-2.6") Language (In Search Box: "lang:c++") (OPTIONS: any language, actionscript, ada, applescript, asp, assembly, autoconf, automake, awk, basic, bat, c, c#, c++, caja, cobol, coldfusion, configure, css, d, eiffel, erlang, fortran, go, haskell, inform, java, java, javascript, jsp, lex, limbo, lisp, lolcode, lua, m4, makefile, maple, mathematica, matlab, messagecatalog, modula2, modula3, objectivec, ocaml, pascal, perl, php, pod, prolog, proto, python, python, r, rebol, ruby, sas, scheme, scilab, sgml, shell, smalltalk, sml, sql, svg, tcl, tex, texinfo, troff, verilog, vhdl, vim, xslt, xul, yacc) File (In Search Box: "file:^.*.java$") Class (In Search Box: "class:HashMap") Function (In Search Box: "function:toString") License (In Search Box: "license:mozilla") (OPTIONS: null/any-license, aladdin/Aladdin-Public-License, artistic/Artistic-License, apache/Apache-License, apple/Apple-Public-Source-License, bsd/BSD-License, cpl/Common-Public-License, epl/Eclipse-Public-License, agpl/GNU-Affero-General-Public-License, gpl/GNU-General-Public-License, lgpl/GNU-Lesser-General-Public-License, disclaimer/Historical-Permission-Notice-and-Disclaimer, ibm/IBM-Public-License, lucent/Lucent-Public-License, mit/MIT-License, mozilla/Mozilla-Public-License, nasa/NASA-Open-Source-Agreement, python/Python-Software-Foundation-License, qpl/Q-Public-License, sleepycat/Sleepycat-License, zope/Zope-Public-License) Case Sensitive (In Search Box: "case:no") (OPTIONS: yes, no) Also of use in understanding the search tool would be the still live FAQs page for Google Code Search. Is there any code search engine that would fully replace Google Code Search's features?

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• Improving SpriteBatch performance for tiles

  - by Richard Rast

  I realize this is a variation on what has got to be a common question, but after reading several (good answers) I'm no closer to a solution here. So here's my situation: I'm making a 2D game which has (among some other things) a tiled world, and so, drawing this world implies drawing a jillion tiles each frame (depending on resolution: it's roughly a 64x32 tile with some transparency). Now I want the user to be able to maximize the game (or fullscreen mode, actually, as its a bit more efficient) and instead of scaling textures (bleagh) this will just allow lots and lots of tiles to be shown at once. Which is great! But it turns out this makes upward of 2000 tiles on the screen each time, and this is framerate-limiting (I've commented out enough other parts of the game to make sure this is the bottleneck). It gets worse if I use multiple source rectangles on the same texture (I use a tilesheet; I believe changing textures entirely makes things worse), or if you tint the tiles, or whatever. So, the general question is this: What are some general methods for improving the drawing of thousands of repetitive sprites? Answers pertaining to XNA's SpriteBatch would be helpful but I'm equally happy with general theory. Also, any tricks pertaining to this situation in particular (drawing a tiled world efficiently) are also welcome. I really do want to draw all of them, though, and I need the SpriteMode.BackToFront to be active, because

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• What do you call an obfuscator that isn't an obfuscator?

  - by Alex.Davies

  SmartAssembly, formerly {smartassembly}, version 5 is now available as an Early Access Build. You can get it here: http://www.red-gate.com/MessageBoard/viewforum.php?f=116 We're having second thoughts about the name change though. It isn't that we like the curly brackets, far from it. The trouble is that the first rule of product naming is to name a product by what it does. SmartAssembly may make an assembly smarter, but that's not something people really google for. The trouble is, I can't think of a better name for it. That's because SmartAssembly really does two completely separate things: Obfuscates Sets up your assembly for the awesome exception reports which get sent to you whenever your application crashes. You may have been (un?)lucky enough to see one in reflector if you use it. This is what those exception reports look like when they arrive back with the developer: Look at all those local variables! If you ask me, this is much cooler than the obfuscation. So obviously we don't want to call it just "Red Gate Obfuscator" or something, because it doesn't do justice to the exception reporting. What would you call it?

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• How to search for a tester?

  - by MainMa

  As a freelance developer, a few times I tried to find some testers to be able to let them test my software/web applications. If I try to find them, it's because most of the customers are not intended to hire external testers and don't see why this can benefit to them, so products are UI-untested and buggy. I tried lots of things. Discussion boards for IT people, specific websites for people who search for a job. Every time I clearly precise that I'm looking for product testers. I completely failed to find anybody for this job. I found instead two types of people: Non IT people who try to qualify as testers, but don't have enough skills for that, and don't really know what testing is and how to do it, Programmers, who are skilled as programmers, but not as testers, and who mostly don't understand neither what testing is about (or think it's the same thing as code review, or it consists in writing unit tests). Of course, they submit general programmers resumes, where they describe their high experience in Assembler and C++, but don't tell anything about anything related to the job of a tester. What I'm doing wrong? Isn't it called "tester"? Is there at least a tester job, different from general programming job? Is there any precise requirement to require from each candidate which can eliminate non IT people and general programmers?

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• Author has inserted copyright into code with gnu public license notice - implications?

  - by Nicholas Pickering

  I've found a project on Github that I'm interested in contributing to which claims to be open source and has a GPL license included with it. But the original author has added a copyright notification to each source file. I'm not sure why but I don't feel right contributing to a project that's always going to have someone else's name on it. It really breaks the community-created feel, and makes me uneasy about what the author might choose to do with the project next. What are the implications of copyrighting open source GPL code as so? What power does this give the original author over a contributor? # Copyright (C) 2012, 2013 __AUTHORNAME__ # This file is part of __PROJECTNAME__. # # __PROJECTNAME__ is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # __PROJECTNAME__ is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License

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• GetData() error creating framebuffer

  - by Lelezeus

  I'm currently porting a game written in C# with XNA library to Android with Monogame. I have a Texture2D and i'm trying to get an array of uint in this way: Texture2d textureDeform = game.Content.Load<Texture2D>("Texture/terrain"); uint[] pixelDeformData = new uint[textureDeform.Width * textureDeform.Height]; textureDeform.GetData(pixelDeformData, 0, textureDeform.Width * textureDeform.Height); I get the following exception: System.Exception: Error creating framebuffer: Zero at Microsoft.Xna.Framework.Graphics.Texture2D.GetTextureData (Int32 ThreadPriorityLevel) [0x00000] in :0 I found that the problem is in private byte[] GetTextureData(int ThreadPriorityLevel) creating the framebuffer: private byte[] GetTextureData(int ThreadPriorityLevel) { int framebufferId = -1; int renderBufferID = -1; GL.GenFramebuffers(1, ref framebufferId); // framebufferId is still -1 , why can't be created? GraphicsExtensions.CheckGLError(); GL.BindFramebuffer(All.Framebuffer, framebufferId); GraphicsExtensions.CheckGLError(); //renderBufferIDs = new int[currentRenderTargets]; GL.GenRenderbuffers(1, ref renderBufferID); GraphicsExtensions.CheckGLError(); // attach the texture to FBO color attachment point GL.FramebufferTexture2D(All.Framebuffer, All.ColorAttachment0, All.Texture2D, this.glTexture, 0); GraphicsExtensions.CheckGLError(); // create a renderbuffer object to store depth info GL.BindRenderbuffer(All.Renderbuffer, renderBufferID); GraphicsExtensions.CheckGLError(); GL.RenderbufferStorage(All.Renderbuffer, All.DepthComponent24Oes, Width, Height); GraphicsExtensions.CheckGLError(); // attach the renderbuffer to depth attachment point GL.FramebufferRenderbuffer(All.Framebuffer, All.DepthAttachment, All.Renderbuffer, renderBufferID); GraphicsExtensions.CheckGLError(); All status = GL.CheckFramebufferStatus(All.Framebuffer); if (status != All.FramebufferComplete) throw new Exception("Error creating framebuffer: " + status); ... } The frameBufferId is still -1, seems that framebuffer could not be generated and I don't know why. Any help would be appreciated, thank you in advance.

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• Little mysterious RowMatch

  - by kishore.kondepudi(at)oracle.com

  Incidentally this was the first piece of code i ever wrote in ADF.The requirement was we have tax rates which are read from a table.And there can be different type of tax rates called certificates or exceptions based on the rate_type column in the tax rates table.The simplest design i chose was to create an EO on the tax rates table and create two VO's called CertificateVO and ExceptionVO based on the same EO.So far so good.I wrote all the business logic in the EO and completed the model project.The CertificateVO has the query as select * from tax_rates TaxRateEO where rate_type='CERTIFICATE' and similary the ExceptionVO is also built.The UI is pretty simple and it has two tabs called Certificates and Exceptions and each table has a button to create a tax rate.The certificate tab is driven by CertificateVO and exception tab is driven by ExceptionVO.The CertificateVO has default value of rate_type set to 'CERTIFICATE' and ExceptionVO has default value of rate_type to 'EXCEPTION' to default values for new records.So far so good.But on running the UI i noticed a strange thing,When i create a new row in Certificate i see the same row in Exception too and vice-versa.i.e; what ever row i create in one VO it also appears in the second one although it shouldn't be.I couldn't understand the reason for behavior even though an explicit where clause is present.Digging through documentation i found that ADF doesnt apply the where clause to new rows instead it applies something called as RowMatch to them.RowMatch in simple terms is a where condition applied to the VO rows at runtime.Since we had both VO's based on the same EO we have the same entity cache.The filter factor for new rows to be shown in VO at runtime is actually RowMatch than the where clause defined in the VO.The default RowMatch is empty as a result any new row appears in both the VO's since its from same entity cache.The solution to this problem is to use polymorphic view objects which can do the row filter based on configuration or override the getRowMatch() method in the VOImpl and pass the custom where filter instead of default RowMatch.Eg:@Overridepublic RowMatch getRowMatch(){    return new RowMatch("rate_type='CERTIFICATE'");}similarly for ExceptionVO too.With proper RowMatch in place new rows will route themselves to appropriate VO.PS: The behavior(Same row pushed to both VO's from entity cache) is also called as ViewLink Consistency.Try it out!

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• Debugging Windows Service Timeout Error 1053

  - by Joe Mayo

  If you ever receive an Error 1053 for a timeout when starting a Windows Service you've written, the underlying problem might not have anything to do with a timeout.  Here's the error so you can compare it to what you're seeing: --------------------------- Services --------------------------- Windows could not start the Service1 service on Local Computer.   Error 1053: The service did not respond to the start or control request in a timely fashion. --------------------------- OK   --------------------------- Searching the Web for a solution to this error in your Windows Service will result in a lot of wasted time and advice that won't help.  Sometimes you might get lucky if your problem is exactly the same as someone else's, but this isn't always the case.  One of the solutions you'll see has to do with a known error on Windows Server 2003 that's fixed by a patch to the .NET Framework 1.1, which won't work.  As I write this blog post, I'm using the .NET Framework 4.0, which is a tad bit past that timeframe. Most likely, the basic problem is that your service is throwing an exception that you aren't handling.  To debug this, wrap your service initialization code in a try/catch block and log the exception, as shown below: using System; using System.Diagnostics; using System.ServiceProcess; namespace WindowsService { static class Program { static void Main() { try { ServiceBase[] ServicesToRun; ServicesToRun = new ServiceBase[] { new Service1() }; ServiceBase.Run(ServicesToRun); } catch (Exception ex) { EventLog.WriteEntry("Application", ex.ToString(), EventLogEntryType.Error); } } } } After you uninstall the old service, redeploy the service with modifications, and receive the same error message as above; look in the Event Viewer/Application logs.  You'll see what the real problem is, which is the underlying reason for the timeout. Joe

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• Google analytics - drop in traffic

  - by Andy

  Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

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• Oracle has some very helpful and free code...I think

  - by Casey

  I found that some of the code that Oracle uses is very useful so I don't have to re-invent the wheel. Given this is at the top of the file where the code in question is: /* * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ If I leave the text intact, put it in my C++ header, and credit oracle for each method, and package the source into a static library...is it still a no-no?

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• Google analytics - drop in traffic

  - by user1001421

  Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

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• Making Modular, Reusable and Loosely Coupled MVC Components

  - by Dusan

  I am building MVC3 application and need some general guidelines on how to manage complex client side interaction between my components. Here is my definition of one component in general way: Component which has it's own controller, model and view. All of the component's logic is placed inside these three parts and component is sort of "standalone", it contains it's own form, data needed for interaction, updates itself with Ajax and so on. Beside this internal logic and behavior of the component, it needs to be able to "Talk" to the outside world. By this I mean it should provide data and events (sort of) so when this component gets embedded in pages can notify other components which then can update based on the current state and data. I have an idea to use client ViewModel (in java-script) which would hookup all relevant components on page and control interaction between them. This would make components reusable, modular - independent of the context in which they are used. How would you do this, I am a bit stuck as I do not know if this is a good approach and there is a technical possibility to achieve this using java-script/jquery. The confusing part is about update via Ajax, how to ensure that component is properly linked to ViewModel when component is Ajax updated (or even worse removed or dynamically added). Also, how should this ViewModel be constructed and which technicalities to use here and in components to work as synergy??? On the web, I have found the various examples of the similar approach, but they are oversimplified (even for dummies) or over specific and do not provide valuable resource or general solution for this kind of implementation. If you have some serious examples it would be, also, very helpful. Note: My aim is to make interactions between many components on the same page simpler and more robust and elegant.

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• How to avoid throwing vexing exceptions?

  - by Mike

  Reading Eric Lippert's article on exceptions was definitely an eye opener on how I should approach exceptions, both as the producer and as the consumer. However, I'm still struggling to define a guideline regarding how to avoid throwing vexing exceptions. Specifically: Suppose you have a Save method that can fail because a) Somebody else modified the record before you, or b) The value you're trying to create already exists. These conditions are to be expected and not exceptional, so instead of throwing an exception you decide to create a Try version of your method, TrySave, which returns a boolean indicating if the save succeeded. But if it fails, how will the consumer know what was the problem? Or would it be best to return an enum indicating the result, kind of Ok/RecordAlreadyModified/ValueAlreadyExists? With integer.TryParse this problem doesn't exist, since there's only one reason the method can fail. Is the previous example really a vexing situation? Or would throwing an exception in this case be the preferred way? I know that's how it's done in most libraries and frameworks, including the Entity framework. How do you decide when to create a Try version of your method vs. providing some way to test beforehand if the method will work or not? I'm currently following these guidelines: If there is the chance of a race condition, then create a Try version. This prevents the need for the consumer to catch an exogenous exception. For example, in the Save method described before. If the method to test the condition pretty much would do all that the original method does, then create a Try version. For example, integer.TryParse(). In any other case, create a method to test the condition.

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• What's the proper term for a function inverse to a constructor - to unwrap a value from a data type?

  - by Petr Pudlák

  Edit: I'm rephrasing the question a bit. Apparently I caused some confusion because I didn't realize that the term destructor is used in OOP for something quite different - it's a function invoked when an object is being destroyed. In functional programming we (try to) avoid mutable state so there is no such equivalent to it. (I added the proper tag to the question.) Instead, I've seen that the record field for unwrapping a value (especially for single-valued data types such as newtypes) is sometimes called destructor or perhaps deconstructor. For example, let's have (in Haskell): newtype Wrap = Wrap { unwrap :: Int } Here Wrap is the constructor and unwrap is what? The questions are: How do we call unwrap in functional programming? Deconstructor? Destructor? Or by some other term? And to clarify, is this/other terminology applicable to other functional languages, or is it used just in the Haskell? Perhaps also, is there any terminology for this in general, in non-functional languages? I've seen both terms, for example: ... Most often, one supplies smart constructors and destructors for these to ease working with them. ... at Haskell wiki, or ... The general theme here is to fuse constructor - deconstructor pairs like ... at Haskell wikibook (here it's probably meant in a bit more general sense), or newtype DList a = DL { unDL :: [a] -> [a] } The unDL function is our deconstructor, which removes the DL constructor. ... in The Real World Haskell.

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• How to Assure an Effective Data Model

  As a general rule in my opinion the effectiveness of a data model can be directly related to the accuracy and complexity of a project’s requirements. For example there is no need to work on very detailed data models when the details surrounding a specific data model have not been defined or even clarified. Developing data models when the clarity of project requirements is limited tends to introduce designed issues because the proper details to create an effective data model are not even known. One way to avoid this issue is to create data models that correspond to the complexity of the existing project requirements so that when requirements are updated then new data models can be created based any new discoveries regarding requirements on a fine grain level.  This allows for data models to be composed of general entities to be created initially when a project’s requirements are very vague and then the entities are refined as new and more substantial requirements are defined or redefined. This promotes communication amongst all stakeholders within a project as they go through the process of defining and finalizing project requirements.In addition, here are some general tips that can be applied to projects in regards to data modeling.Initially model all data generally and slowly reactor the data model as new requirements and business constraints are applied to a project.Ensure that data modelers have the proper tools and training they need to design a data model accurately.Create a common location for all project documents so that everyone will be able to review a project’s data models along with any other project documentation.All data models should follow a clear naming schema that tells readers the intended purpose for the data and how it is going to be applied within a project.

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• "Programming error" exceptions - Is my approach sound?

  - by Medo42

  I am currently trying to improve my use of exceptions, and found the important distinction between exceptions that signify programming errors (e.g. someone passed null as argument, or called a method on an object after it was disposed) and those that signify a failure in the operation that is not the caller's fault (e.g. an I/O exception). As far as I understand, it makes little sense for an immediate caller to actually handle programming error exceptions, he should instead assure that the preconditions are met. Only "outer" exception handlers at task boundaries should catch them, so they can keep the system running if a task fails. In order to ensure that client code can cleanly catch "failure" exceptions without catching error exceptions by mistake, I create my own exception classes for all failure exceptions now, and document them in the methods that throw them. I would make them checked exceptions in Java. Now I have a few questions: Before, I tried to document all exceptions that a method could throw, but that sometimes creates an unwiedly list that needs to be documented in every method up the call chain until you can show that the error won't happen. Instead, I document the preconditions in the summary / parameter descriptions and don't even mention what happens if they are not met. The idea is that people should not try to catch these exceptions explicitly anyway, so there is no need to document their types. Would you agree that this is enough? Going further, do you think all preconditions even need to be documented for every method? For example, calling methods in IDisposable objects after calling Dispose is an error, but since IDisposable is such a widely used interface, can I just assume a programmer will know this? A similar case is with reference type parameters where passing null makes no conceivable sense: Should I document "non-null" anyway? IMO, documentation should only cover things that are not obvious, but I am not sure where "obvious" ends.

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• Why is CS never a topic of conversation of the layman? [closed]

  - by hydroparadise

  Granted, every profession has it's technicalities. If you are an MD, you better know the anatomy of the human body, and if you are astronomer, you better know your calculus. Yet, you don't have to know these more advance topics to know that smoking might give you lung cancer because of carcinogens or the moon revolves around the earth because of gravity (thank you Discovery Channel). There's sort of a common knowledge (at least in more developed countries) of these more advanced topics. With that said, why are things like recursive descent parsing, BNF, or Turing machines hardly ever mentioned outsided 3000 or 4000 level classes in a university setting or between colleagues? Even back in my days before college in my pursuit of knowledge on how computers work, these very important topics (IMHO) never seem to get the light of day. Many different sources and sites go into "What is a processor?" or "What is RAM?", or "What is an OS?". You might get lucky and discover something about programming languages and how they play a role in how applications are created, but nothing about the tools for creating the language itself. To extend this idea, Dennis Ritchie died shortly after Steve Jobs, yet Dennis Ritchie got very little press compared to Steve Jobs. So, the heart of my question: Does the public in general not care to hear about computer science topics that make the technology in their lives work, or does the computer science community not lend itself to the general public to close the knowledge gap? Am I wrong to think the general public has the same thirst for knowledge on how things work as I do? Please consider the question carefully before answering or vote closing please.

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• AndEngine GLES2 - getting Black screen on emulator 4.1

  - by dizworld.com

  I'm new in andengine . I create following code public class MainActivity extends BaseGameActivity { static final int CAMERA_WIDTH = 800; static final int CAMERA_HEIGHT = 480; public Font mFont; public Camera mCamera; //A reference to the current scene public Scene mCurrentScene; public static BaseActivity instance; public EngineOptions onCreateEngineOptions() { instance = this; mCamera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT); return new EngineOptions(true, ScreenOrientation.LANDSCAPE_SENSOR, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), mCamera); } @Override public void onCreateResources(OnCreateResourcesCallback arg0) throws Exception { mFont = FontFactory.create(this.getFontManager(),this.getTextureManager(), 256, 256,Typeface.create(Typeface.DEFAULT, Typeface.BOLD), 32); mFont.load(); } @Override public void onCreateScene(OnCreateSceneCallback arg0) throws Exception { mEngine.registerUpdateHandler(new FPSLogger()); mCurrentScene = new Scene(); Log.v("Scene","enter"); mCurrentScene.setBackground(new Background(0.09804f, 0.7274f, 0.8f)); // return mCurrentScene; } @Override public void onPopulateScene(Scene arg0, OnPopulateSceneCallback arg1) throws Exception { // TODO Auto-generated method stub } } I got code on sites there is returning scene but in AndEngine GLES2 in method onCreateScene() there is no return scene ... so my First run is BLACK .. any suggestion :)

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• is Java free for mobile development?

  - by exTrace101

  Q1. I would like to know if it's free for a developer (I mean, if I have to pay no royalties to Sun/Oracle) to develop (Android) mobile apps in Java? After reading this snippet about use of Java field, I'm getting the impression that Java is not free for mobile development, is that right? .."General Purpose Desktop Computers and Servers" means computers, including desktop and laptop computers, or servers, used for general computing functions under end user control (such as but not specifically limited to email, general purpose Internet browsing, and office suite productivity tools). The use of Software in systems and solutions that provide dedicated functionality (other than as mentioned above) or designed for use in embedded or function-specific software applications, for example but not limited to: Software embedded in or bundled with industrial control systems, wireless mobile telephones, wireless handheld devices, netbooks, kiosks, TV/STB, Blu-ray Disc devices, telematics and network control switching equipment, printers and storage management systems, and other related systems are excluded from this definition and not licensed under this Agreement... and from http://www.excelsiorjet.com/embedded/ Notice : The Java SE Embedded technology license currently prohibits the use of Java SE in cell phones. Q2. how come these plethora of Android Java developers aren't paying Sun/Oracle a dime?

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• Call DB Stored Procedure using @NamedStoredProcedureQuery Injection

  - by anwilson

  Oracle Database Stored Procedure can be called from EJB business layer to perform complex DB specific operations. This approach will avoid overhead from frequent network hits which could impact end-user result. DB Stored Procedure can be invoked from EJB Session Bean business logic using org.eclipse.persistence.queries.StoredProcedureCall API. Using this approach requires more coding to handle the Session and Arguments of the Stored Procedure, thereby increasing effort on maintenance. EJB 3.0 introduces @NamedStoredProcedureQuery Injection to call Database Stored Procedure as NamedQueries. This blog will take you through the steps to call Oracle Database Stored Procedure using @NamedStoredProcedureQuery.EMP_SAL_INCREMENT procedure available in HR schema will be used in this sample.Create Entity from EMPLOYEES table.Add @NamedStoredProcedureQuery above @NamedQueries to Employees.java with definition as given below - @NamedStoredProcedureQuery(name="Employees.increaseEmpSal", procedureName = "EMP_SAL_INCREMENT", resultClass=void.class, resultSetMapping = "", returnsResultSet = false, parameters = { @StoredProcedureParameter(name = "EMP_ID", queryParameter = "EMPID"), @StoredProcedureParameter(name = "SAL_INCR", queryParameter = "SALINCR")} ) Observe how Stored Procedure's arguments are handled easily in  @NamedStoredProcedureQuery using @StoredProcedureParameter.Expose Entity Bean by creating a Session Facade.Business method need to be added to Session Bean to access the Stored Procedure exposed as NamedQuery. public void salaryRaise(Long empId, Long salIncrease) throws Exception { try{ Query query = em.createNamedQuery("Employees.increaseEmpSal"); query.setParameter("EMPID", empId); query.setParameter("SALINCR", salIncrease); query.executeUpdate(); } catch(Exception ex){ throw ex; } } Expose business method through Session Bean Remote Interface. void salaryRaise(Long empId, Long salIncrease) throws Exception; Session Bean Client is required to invoke the method exposed through remote interface.Call exposed method in Session Bean Client main method. final Context context = getInitialContext(); SessionEJB sessionEJB = (SessionEJB)context.lookup("Your-JNDI-lookup"); sessionEJB.salaryRaise(new Long(200), new Long(1000)); Deploy Session BeanRun Session Bean Client.Salary of Employee with Id 200 will be increased by 1000.

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• Getting Error whileInitializing entities [closed]

  - by R76

  I am new'b as WPF Dev. I am developing Window application in WPF using mvvmlight framework. I have created database in Sqlserver compact 4.0. I have made a Ado.net Entity Data Model. When I trying to initialize the Entity object in service it throws the error like: Error 'The invocation of the constructor on type 'PointOfSale.ViewModels.ProductsViewModel' that matches the specified binding constraints threw an exception.' Line number '7' and line position '10'. stack Trace at System.Windows.Markup.XamlReader.RewrapException(Exception e, IXamlLineInfo lineInfo, Uri baseUri) at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri) at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri) at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream) at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator) at PointOfSale.MainWindow.InitializeComponent() in e:\VarniApplication\PointOfSale\PointOfSale\MainWindow.xaml:line 1 at PointOfSale.MainWindow..ctor() in E:\VarniApplication\PointOfSale\PointOfSale\MainWindow.xaml.cs:line 27 Inner Exception {"Unable to load the specified metadata resource."} My code: xyzEntities entites; public ctor() { entites = new xyzEntities(); //This line throws an error } I have installed sql server compact 4.0 from web installer 3.0. and added the sql server compact toolbox from the extension manager. Tell me if I am missing something to install or missing something to write code.

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• Laser range finder, what language to use? Beginner advice

  - by DrOnline

  I hope this is the right place. I am a programming beginner, and I want to make a laser range finder, and I need advice about how to proceed etc. In a few weeks I will get a lot of dirt cheap 3-5V lasers and some cheap usb webcams. I will point the laser and webcam in parallel, and somehow use trigonometry and programming to determined distance. I have seen online that others made done it this way, I have purposefully not looked at the details too much because I want to develop it on my own, and learn, but I know the general outline. I have a general idea of how to proceed. The program loads in a picture from the webcam, and I dunno how images work really, but I imagine there is a format that is basically an array of RGB values.. is this right? I will load in the red values, and find the most red one. I know the height difference between the laser and the cam. I know the center dot in the image, I know the redmost dot. I'm sure there's some way to figure out some range there. TO THE POINT: 1) Is my reasoning sound thus far, especially in terms of image analysis? I don't need complete solutions, just general points 2) What I need to figure out, is what platform to use. I have an arduino... apparently, I've read it's too weak to process images. Read that online. I know some C I know some Python I have Matlab. Which is the best option? I do not need high sampling rates, I have not decided on whether it should be automated or whether I should make a GUI with a button to press for samples. I will keep it simple and expand I think. I also do not need it to be super accurate, I'm just having fun here. Advice!

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• SignalR Server Error "The ConnectionId is in the incorrect format." with SignalR-ObjC Library

  - by ozzotto

  Before asking a separate question I've done lots of googling about it and added a comment in the already existing stackoverflow question. I have a SignalR Hub (tried both v. 1.1.3 and 2.0.0-rc) in my server with the below code: [HubName("TestHub")] public class TestHub : Hub { [Authorize] public void TestMethod(string test) { //some stuff here Clients.Caller.NotifyOnTestCompleted(); } } The problem persists if I remove the Authorize attribute. And in my iOS client I try to call it with the below code: SRHubConnection *hubConnection = [SRHubConnection connectionWithURL:_baseURL]; SRHubProxy *hubProxy = [hubConnection createHubProxy:@"TestHub"]; [hubProxy on:@"NotifyOnTestCompleted" perform:self selector:@selector(stopConnection)]; hubConnection.started = ^{ [hubProxy invoke:@"TestMethod" withArgs:@[@"test"]]; }; //received, error handling [hubConnection start]; When the app starts the user is not logged in and there is no open SignalR connection. The users logs in by calling a Login service in the server which makes use of WebSecurity.Login method. If the login service returns success I then make the above call to SignalR Hub and I get the server error 500 with description "The ConnectionId is in the incorrect format.". The full server stacktrace is the following: Exception information: Exception type: InvalidOperationException Exception message: The ConnectionId is in the incorrect format. at Microsoft.AspNet.SignalR.PersistentConnection.GetConnectionId(HostContext context, String connectionToken) at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(HostContext context) at Microsoft.AspNet.SignalR.Hubs.HubDispatcher.ProcessRequest(HostContext context) at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(IDictionary`2 environment) at Microsoft.Owin.Mapping.MapMiddleware.<Invoke>d__0.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) Request information: Request URL: http://myserverip/signalr/signalr/connect?transport=webSockets&connectionToken=axJs EQMZxpmUopL36owSUkdhNs85E0fyB2XvV5R5znZfXYI/CiPbTRQ3kASc3 mq60cLkZU7coYo1P fbC0U1LR2rI6WIvCNIMOmv/mHut/Unt9mX3XFkQb053DmWgCan5zHA==&connectionData=[{"Name":"testhub"}] Request path: /signalr/signalr/connect User host address: User: Is authenticated: False Authentication Type: Thread account name: IIS APPPOOL\DefaultAppPool Thread information: Thread ID: 14 Thread account name: IIS APPPOOL\DefaultAppPool Is impersonating: True Stack trace: at Microsoft.AspNet.SignalR.PersistentConnection.GetConnectionId(HostContext context, String connectionToken) at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(HostContext context) at Microsoft.AspNet.SignalR.Hubs.HubDispatcher.ProcessRequest(HostContext context) at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(IDictionary`2 environment) at Microsoft.Owin.Mapping.MapMiddleware.<Invoke>d__0.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) I understand this is some kind of authentication and user identity mismatching but up to now I have found no way of solving it. All other questions suggest stoping the opened connection when the user identity changes but as I mentioned above I have no open connection before the user logs in successfully. Any help would be much appreciated. Thank you.

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