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  • andEngine dynamic sprites

    - by Blucreation
    Ive just started with andEngine the past week and i only started learning java/android 3 weeks. I can use a for loop to add multiple sprites to the screen but when i try to check collisions on them it only does it to one and not the rest. I want to be able to add a specific number for sprites made from the same texture to the scene, add collision detection to them and also make them slide across the screen (im making a game where you avoid the obstacles). My simple code: private void createobstacle(float pX, float pY) { obstacle = new AnimatedSprite(pX, pY, this.mObjTextureRegion.deepCopy(), getVertexBufferObjectManager()); obstacle.setScale(MathUtils.random(0.5f, 3f)); scene.attachChild(obstacle); } private void createobstacle(int num) { for(int i=0; i<=num; i++ ) { final float xPos = MathUtils.random(30.0f, (CAMERA_WIDTH - 30.0f)); final float yPos = MathUtils.random(30.0f, (CAMERA_HEIGHT - 30.0f)); createobstacle(xPos, yPos); } } Ive read about arrays but i cannot find any tutorials about anything im stuck with. Any help would be great!

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  • How bad it's have two methods with the same name but differents signatures in two classes?

    - by Super User
    I have a design problem relationated with the public interface, the names of methods and the understanding of my API and my code. I have two classes like this: class A: ... function collision(self): .... ... class B: .... function _collision(self, another_object, l, r, t, b): .... The first class have one public method named collision and the second have one private method called _collision. The two methods differs in arguments type and number. In the API _m method is private. For the example let's say that the _collision method checks if the object is colliding with another_ object with certain conditions l, r, t, b (for example, collide the left side, the right side, etc) and returns true or false according to the case. The collision method, on the other hand, resolves all the collisions of the object with other objects. The two methods have the same name because I think is better avoid overload the design with different names for methods who do almost the same think, but in distinct contexts and classes. This is clear enough to the reader or I should change the method's name?

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  • Companies and Ships

    - by TechnicalWriting
    I have worked for small, medium, large, and extra large companies and they have something in common with ships. These metaphors have been used before, I know, but I will have a go at them.The small company is like a speed boat, exciting and fast, and can turn on a dime, literally. Captain and crew share a lot of the work. A speed boat has a short range and needs to refuel a lot. It has difficulty getting through bad weather. (Small companies often live quarter to quarter. By the way, if a larger company is living quarter to quarter, it is taking on water.)The medium company is is like a battleship. It can maneuver, has a longer range, and the crew is focused on its mission. Its main concern are the other battleships trying to blow it out of the water, but it can respond quickly. Bad weather can jostle it, but it can get through most storms.The large company is like an aircraft carrier; a floating city. It is well-provisioned and can carry a specialized load for a very long range. Because of its size and complexity, it has to be well-organized to be effective and most of its functions are specialized (with little to no functional cross-over). There are many divisions and layers between Captain and crew. It is not very maneuverable; it has to set its course well in advance and have a plan of action.The extra large company is like a cruise liner. It also has to be well-organized and changes in direction are often slow. Some of the people are hard at work behind the scenes to run the ship; others can be along for the ride. They sail the same routes over and over again (often happily) with the occasional cosmetic face-lift to the ship and entertainment. It should stay in warm, friendly waters and avoid risky speed through fields of ice bergs.I have enjoyed my career on the various Ships of Technical Writing, but I get the most of my juice from the battleship where I am closer to the campaign and my contributions have the greater impact on success.Mark Metcalfewww.linkedin.com/in/MarkMetcalfe

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  • How to have Windows 7 remember a password for a Domain

    - by Kelly Jones
    About eighteen months ago, I wrote a post covering how to clear saved passwords in Windows XP.  This week at work I was reminded how useful it is to not only deleted saved passwords, but to also setup wildcard credentials using this same interface. The scenario that I run into as consultant working at a client site, is that my laptop is not a member of the Windows Domain that my client uses to secure their network. So, when I need to access file shares, shared printers, or even the clients internal websites, I’m prompted for a name and password.  By creating a wildcard entry on my laptop (for the user account that the client issued to me), I avoid this prompt and can seamlessly access these resources.  (This also works when you’ve configured Outlook to access Exchange via RPC over HTTP.) How to create a credential wild card entry in Windows 7: Go to your Start Menu --> Type "user" into the Search box Click on the “Manage your credentials” in the column on the left Click on the “Add a Windows credential” link Enter the Domain (in my case my client’s domain), something like this: *.contoso.com Enter the username and password That’s it.  You should now be able to access resources in that Domain without being prompted for your name and password.  Please note: if you are required to change your password periodically for that domain, you’ll need to update your saved password as well.

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  • Extremely simple online multiplayer game

    - by Postscripter
    I am considering creating a simple multiplayer game, which focuses on physics and can accommodate up to 30 players per session. Very simple graphics, but smart physics (pushing, weight and gravity, balance) is required. After some research I found a good java script (framework ??) called box2d.js I found the demo to be excellent. this is is kind of physics am looking for in my game. Now, what other frameworks will I need? Node.js?? Prototype.js?? (btw, I found the latest versoin of protoype.js to be released in 2010...?? is this still supported? Should I avoid using it?) What bout HTML 5 and Canvas? would I need them? websockets? Am a beginner in web programming + game programming world. but I will learn fast, am computer science graduate. (but no much web expeience but know essentionals javascript, html, css..). I just need a guiding path to build my game. Thanks

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  • running adb via wifi on ubuntu 13.04

    - by Blaze Tama
    First, im new on linux so please bear with me. I have a rooted android phone and i was able to run the adb via wifi network on windows, where i just need to go to the adb's directory and type adb connect. However, i can't just do that in my ubuntu. Everytime i enter adb connect, the terminal always said that i dont have the adb and i must install it. When i check the ADT Bundle (I downloaded the bundled one from here), i can see the adb is there inside the platform-tools folder. I already tried to change the directory to the platform-tools and run the adb connect from there, but its still not working. Do i need to install the adb again via terminal? Or did i miss something? You may be wondering why dont i just download the adb (again) via terminal and do trial and error? The answer is because i dont have a good internet connection, so i want to avoid unnecessary downloads. Thanks for your time :D

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  • Enterprise Instrumentation: The 'sessionName' parameter of value 'TraceSession' is not valid

    - by Michael Freidgeim
    We are still using Enterprise Instrumentation(that was created during .Net 1.1 time)In new Server 2008 environment and IIS 7 we have the following errors:The 'sessionName' parameter of value 'TraceSession' is not valid. A trace session of this name does not exist in the TraceSessions configuration file for Windows Trace Session Manager service. Ensure that a session of this name exists in the TraceSessions configuration file and that the Windows Trace Session Manager service is started.   at Microsoft.EnterpriseInstrumentation.EventSinks.TraceEventSink..ctor(IDictionary parameters, EventSource eventSource)   --- End of inner exception stack trace ---   at System.RuntimeMethodHandle._InvokeConstructor(IRuntimeMethodInfo method, Object[] args, SignatureStruct& signature, RuntimeType declaringType)   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)   at Microsoft.EnterpriseInstrumentation.EventSinks.EventSink.CreateNewEventSinks(DataRow[] eventSinkRows, EventSource eventSource)I’ve seen the same errors on development Win7 machines when using IIS. It seems not a problem on Cassini.I've checked ,that Windows Trace Session Manager Service has started and The file C:\Program Files (x86)\Microsoft Enterprise Instrumentation\Bin\Trace Service\TraceSessions.config has corresponding entry<?xml version="1.0" encoding="utf-8" ?><configuration >                <defaultParameters minBuffers="4" maxFileSize="10" maxBuffers="25" bufferSize="20" logFileMode="sequential" flushTimer="3" />                <sessionList>                                 <session name="TraceSession" enabled="false" fileName="C:\Program Files (x86)\Microsoft Enterprise Instrumentation\Bin\Trace Service\Logs\TraceLog.log" />                </sessionList></configuration>The errors still continue, but I was able to disable  the parameter in  eventSink configuration   <eventSink name=" traceSink" description=" Outputs events to the Windows Event Trace." type ="Microsoft.EnterpriseInstrumentation.EventSinks.TraceEventSink ">                <!-- MNF disabled parameter to  avoid error "The 'sessionName' parameter of value 'TraceSession' is not valid"                      < parameter name ="sessionName " value ="TraceSession " />                    -->    </ eventSink>Related old post http://bytes.com/topic/net/answers/104761-enterprise-instrumentation-windows-trace-session-managerOne day I wish to replace all EnterpriseInstrumentation calls with NLog.

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  • Part 4: Development Standards or How to share

    - by volker.eckardt(at)oracle.com
    Although we usually introduce the custom development part in EBS projects as “a small piece only” and “we will avoid as best as possible”, the development effort can be enormous and should therefore be well addressed by project standards. Any additional solution or additional software tool or product shall influence the custom development rules (by adding, removing or replacing sections). It is very common in EBS projects to create a so called “MD.030 Development Standards” document and put everything what’s related to development conventions into it. This document gets approval and will be shared among all developers. Later, additional sections have to be added, and usually the development lead is responsible for doing this. However, sometimes used development techniques are not documented properly, and therefore the development solutions deviate from each other, or from the initially agreed standards. My advice would be the following: keep the MD.030 as a base document, and add a Wiki on top. The “Development Wiki” covers the following: Collect input from every developer without updating the MD.030 directly Collect additional topics that might need further specification Allow a discussion about such topics by reviewing/updating the wiki directly Add also decisions or open questions right into it. In one of my own projects we were using this “Developer Wiki” quite extensive, and my experience is very positive. We had different sections in it, good cross references, but also additional material like code templates, links to external web pages etc. By using this wiki, the development standards became “owned” by the right group of people, the developers. They recognized that information sharing can improve the overall development quality, but will also reduce the workload on individuals. Finally, the wiki was much more accurate and helpful for the daily development work than our initial MD.030, and we all decided to retire the document completely. Summary: Information sharing in the development area is very important! The usual “MD.030 Development Standards“ is a good starting point, but should be combined with a “Development Wiki”, allowing everyone to address and discuss necessary improvements. A well-structured Wiki can replace the document in some sections completely. Side Note: The corresponding task in Oracle OUM (Oracle Unified Method) is DS.050 ‘Determine Design and Build Standards’ Volker

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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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  • Loadbalancing Questions

    - by Van Holtz
    I have been learning networking for about 4 months. Wrote a single standalone Multiplayer server and succeeded with authoritative approach. Now I want to extend it by splitting the single server into clusters to allow even more players to log in to avoid latency issues. Now I have protyped the Loadbalancing server and its running pretty good so far. This is my architecture, I have a master server which acts as a proxy, every sub servers(chat, login, game) connect to the master server as well as all the clients. when a client connects, Client Request: Send Request - MS(Master) - Decides which SS(SubServer) to forward to - Forwards Request to SS - SS - Analyze Message - Send Response to MS - Decides which Client to forward to - Forwards Response to Client Well, it looks like its going through lots of stages. it takes double the time to process the message than a single server approach. i feel like my model isnt the best or i may be wrong. is there any better model or the one they use in professional games? I still want a Master-SubServer approach. I just want to clarify that I'm going in the right direction before writing all my codes. Thanks for any answer :)

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  • Law of Demeter confusion [duplicate]

    - by user2158382
    This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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  • dpkg in uninterruptible sleep

    - by Khaled
    I have several Ubuntu servers 10.04. Today, I tried to upgrade some packages on one of these servers and the process got stuck. I logged in using another SSH session and I found that dpkg is in D state (uninterruptible sleep). According to what I have read, this state results generally from I/O waiting like waiting for NFS share. I can not understand why dpkg will block in this state. I can not see any obvious problems other than this. Here is the output of ps to show the blocking process: $ ps axo pid,cmd,s,wchan | grep dpkg 22571 /usr/bin/dpkg --status-fd 2 D call_rwsem_down_read_failed This process can not be killed even with kill -9. So, I will not be able to install/upgrade any package unless I reboot the server. What makes it worse is that the remote reboot does not succeed in such a case (having processes in D state). Can anyone help with this? How can I avoid this in the future.

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  • Is StackOverflow making me stupid? [closed]

    - by Ayush Goyal
    Possible Duplicate: When stuck, how quickly should one resort to Stack Overflow? Its good that solution to almost every programming problem is available at my disposal, either someone has asked it before or programming gurus are waiting for me to post it..sometimes its just the matter of seconds after posting the question and someone points out the error-causing-line or proposes alternate (easier, lightweight and efficient) solution. But today it struck me "is this making me dumb?" In good (umm..not so good) old days I used to figure out the source of my problem and then work it out myself, though it used to eat up lot of time but it helped in developing my logical thinking as it used to make an impression in my mind due to which I tend to avoid that situation in future codes. Now, as soon as I encounter a problem I just give it a shot or two and head towards the community. Many times after looking at the solution it turns out that answer was all in front of me..all I needed was to take a break, hover it once and its solved. Both the approaches make me feel guilty, for wasting time when I could have asked and solved it within minutes OR being too lazy to look over it again before posting the code snippet.

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • configuration issue with respect to .htaccess file on ubuntu

    - by Registered User
    I am building an application tshirtshop I have following configuration in /etc/apache2/sites-enabled/tshirtshop <VirtualHost *:80> ServerAdmin webmaster@localhost DocumentRoot /var/www/tshirtshop <Directory /var/www/tshirtshop> Options Indexes FollowSymLinks AllowOverride All Order allow,deny allow from all </Directory> ErrorLog ${APACHE_LOG_DIR}/error.log # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel warn CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost> and following in .htaccess file in location /var/www/tshirtshop/.htaccess <IfModule mod_rewrite.c> # Enable mod_rewrite RewriteEngine On # Specify the folder in which the application resides. # Use / if the application is in the root. RewriteBase /tshirtshop #RewriteBase / # Rewrite to correct domain to avoid canonicalization problems # RewriteCond %{HTTP_HOST} !^www\.example\.com # RewriteRule ^(.*)$ http://www.example.com/$1 [R=301,L] # Rewrite URLs ending in /index.php or /index.html to / RewriteCond %{THE_REQUEST} ^GET\ .*/index\.(php|html?)\ HTTP RewriteRule ^(.*)index\.(php|html?)$ $1 [R=301,L] # Rewrite category pages RewriteRule ^.*-d([0-9]+)/.*-c([0-9]+)/page-([0-9]+)/?$ index.php?DepartmentId=$1&CategoryId=$2&Page=$3 [L] RewriteRule ^.*-d([0-9]+)/.*-c([0-9]+)/?$ index.php?DepartmentId=$1&CategoryId=$2 [L] # Rewrite department pages RewriteRule ^.*-d([0-9]+)/page-([0-9]+)/?$ index.php?DepartmentId=$1&Page=$2 [L] RewriteRule ^.*-d([0-9]+)/?$ index.php?DepartmentId=$1 [L] # Rewrite subpages of the home page RewriteRule ^page-([0-9]+)/?$ index.php?Page=$1 [L] # Rewrite product details pages RewriteRule ^.*-p([0-9]+)/?$ index.php?ProductId=$1 [L] </IfModule> the site is working on localhost and is working as if there is no .htaccess rule specified i.e. if I were to view a page as http://localhost/tshirtshop/nature-d2 then I get a 404 Error but if I view the same page as http://localhost/tshirtshop/index.php?DepartmentId=2 then I can view it. sudo apache2ctl -M Loaded Modules: core_module (static) log_config_module (static) logio_module (static) mpm_prefork_module (static) http_module (static) so_module (static) alias_module (shared) auth_basic_module (shared) authn_file_module (shared) authz_default_module (shared) authz_groupfile_module (shared) authz_host_module (shared) authz_user_module (shared) autoindex_module (shared) cgi_module (shared) deflate_module (shared) dir_module (shared) env_module (shared) mime_module (shared) negotiation_module (shared) php5_module (shared) reqtimeout_module (shared) rewrite_module (shared) setenvif_module (shared) status_module (shared) Syntax OK What is the mistake if any one can point out in above configuration, or else I need to check any thing else?

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  • Is a 302 redirect to a random URL from the homepage an SEO problem?

    - by CookieMonster
    I originally posted this on Stackoverflow, but I believe here is a better place to ask. My web application is very similar to notepad.cc which redirects to a randomly generated URL upon access, e.g. http://myapp.com/roTr94h4Gd. (Please note that notepad.cc is not my site.) Probably because of this redirect feature, when I do "fetch as Google" or "fetch as Bingbot", I get a 302 and no html content. Not even a <html></html> tag. HTTP/1.1 302 Moved Temporarily Server: nginx/1.4.1 Date: Tue, 01 Oct 2013 04:37:37 GMT Content-Type: text/html Transfer-Encoding: chunked Connection: keep-alive X-Powered-By: PHP/5.4.17-1~dotdeb.1 Set-Cookie: PHPSESSID=vp99q5e5t5810e3bnnnvi6sfo2; expires=Thu, 03-Oct-2013 04:37:37 GMT; path=/ Expires: Thu, 19 Nov 1981 08:52:00 GMT Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0 Pragma: no-cache Location: /roTr94h4Gd How should I avoid 302 in this case? I suppose I could modify my site to prevent the redirect, but it is a necessary feature of my web app to generate a random URL on each access. I added <meta name="fragment" content="!"> tag into my index page and set it to return a static snapshot of my page when the flag is set. But this still returns a 302. I also added a header to return 200 before redirecting, but this had no effect, either. Could someone tell me a good suggestion to solve this problem?

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  • Moving characters on a grid [on hold]

    - by madmax1
    i am developing my first game with C++. My game uses a grid of rectangles. I have a class Board which manages the grid as a whole, initializes the terrain, places/removes characters, etc. It has a 2D vector of a class Field, which handles the Structure of the field, contained Objects, Characters, etc. Field again contains a vector of class Character, which are positioned on the field. Now i want to implement the functionality to move a character on the board, however dont know which is best practice to do so. Should i implement a moveCharacter(character, offset) function in Board, make it search for the character and move it? Or should i implement a function move(offset) in Character? This sure would be nicest, however makes characters necessary to know the board they are on, or the field which in turn knows the board. On the one hand i feel like i should avoid inclusion between classes as much as possible e.g. to increase portability of classes for different projects, on the other hand i think the character.move() functionality is most comfortable for further development. Im pretty new to "bigger" C++ projects and these kind of design questions pop up more and more often lately and i have troubles deciding. Thanks a lot for any advice!

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  • General List of Common Programming Errors

    - by javamonkey79
    As one journey's from apprentice to journeyman to master I've noticed that one accumulates a list of best practices for things they've been bitten by. Personally, I write most of my stuff in java & SQL so my list tends to be slated towards them. I've accumulated the following: When doing list removal, always reverse iterate Avoid adding items to a list you are currently iterating on Watch out for NullPointerExceptions Now, I know there are language specific "common errors" links out there like this one. And I'm also aware of the pragmatic programmer tips, Martin Fowler's "code smells". Does anyone know of any good lists out there of things like I've listed above (re: list removal, adding items, etc). My guess is that there are some good QA folks out there that can probably throw me a bone here. I'm not looking for things the compiler can catch - I'm looking for common things that cause bugs. In the event that there isn't a list out there already then I welcome posting your own findings here. Thanks in advance!

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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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  • PDFtk Password Protection Help

    - by Dave W.
    I am using Ubuntu 11.10 and am looking for a solution to password protect a bunch of pdf files in a directory in batch. I came across PDFtk and it looks like it might do what I need, but I've reviewed the command line PDFtk examples and can't figure out if there is a way to do it in batch without having to individually specify the output file name for every file. I'm hoping a command-line guru can take a look at the PDFtk syntax and tell me if there is some trick / command that will allow me to password protect a directory of pdf files (e.g., *.pdf) and overwrite the existing files using the same name, or consistently rename the individual output files without having to specify each output name individually. Here's a link to the PDFtk command line examples page: http://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/ Thanks for your help. I think I've answered my own question. Here's a bash script that appears to do the trick. I'd welcome help evaluating why the code I've commented out doesn't work... #!/bin/bash # Created by Dave, 2012-02-23 # This script uses PDFtk to password protect every PDF file # in the directory specified. The script creates a directory named "protected_[DATE]" # to hold the password protected version of the files. # # I'm using the "user_pw" parameter, # which means no one will be able to open or view the file without # the password. # # PDFtk must be installed for this script to work. # # Usage: ./protect_with_pdftk.bsh [FILE(S)] # [FILE(S)] can use wildcard expansion (e.g., *.pdf) # This part isn't working.... ignore. The goal is to avoid errors if the # directory to be created already exists by only attempting to create # it if it doesn't exists # #TARGET_DIR="protected_$(date +%F)" #if [ -d "$TARGET_DIR" ] #then #echo # echo "$TARGET_DIR directory exists!" #else #echo # echo "$TARGET_DIR directory does not exist!" #fi # mkdir protected_$(date +%F) for i in *pdf ; do pdftk "$i" output "./protected_$(date +%F)/$i" user_pw [PASSWORD]; done echo "Complete. Output is in the directory: ./protected_$(date +%F)"

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  • How should I architect a personal schedule manager that runs 24/7?

    - by Crawford Comeaux
    I've developed an ADHD management system for myself that's attempting to change multiple habits at once. I know this is counter to conventional wisdom, but I've tried the conventional for years & am now trying it my way. (just wanted to say that to try and prevent it from distracting people from the actual question) Anyway, I'd like to write something to run on a remote server that monitors me, helps me build/avoid certain habits, etc. What this amounts to is a system that: runs 24/7 may have multiple independent tasks to run at once may have tasks that require other tasks to run first lets tasks be scheduled by specific time, recurrence (ie. "run every 5 mins"), or interval (ie. "run from 2pm to 3pm") My first naive attempt at this was just a single PHP script scheduled to run every minute by cron (language was chosen in order to use a certain library, but no longer necessary). The logic behind when to run this or that portion of code got hairy pretty quick. So my question is how should I approach this from here? I'm not tied to any one language, though I'm partial to python/javascript. Thoughts: Could be done as a set of scripts that include a scheduling mechanism with one script per bit of logic...but the idea just feels wrong to me. Building it as a daemon could be helpful, but still unsure what to do about dozens of if-else statements for detecting the current time

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  • How to Reap Anticipated ROI in Large-Scale Capital Projects

    - by Sylvie MacKenzie, PMP
    Only a small fraction of companies in asset-intensive industries reliably achieve expected ROI for major capital projects 90 percent of the time, according to a new industry study. In addition, 12 percent of companies see expected ROIs in less than half of their capital projects. The problem: no matter how sophisticated and far-reaching the planning processes are, many organizations struggle to manage risks or reap the expected value from major capital investments. The data is part of the larger survey of companies in oil and gas, mining and metals, chemicals, and utilities industries. The results appear in Prepare for the Unexpected: Investment Planning in Asset-Intensive Industries, a comprehensive new report sponsored by Oracle and developed by the Economist Intelligence Unit. Analysts say the shortcomings in large-scale, long-duration capital-investments projects often stem from immature capital-planning processes. The poor decisions that result can lead to significant financial losses and disappointing project benefits, which are particularly harmful to organizations during economic downturns. The report highlights three other important findings. Teaming the right data and people doesn’t guarantee that ROI goals will be achieved. Despite involving cross-functional teams and looking at all the pertinent data, executives are still failing to identify risks and deliver bottom-line results on capital projects. Effective processes are the missing link. Project-planning processes are weakest when it comes to risk management and predicting costs and ROI. Organizations participating in the study said they fail to achieve expected ROI because they regularly experience unexpected events that derail schedules and inflate budgets. But executives believe that using more-robust risk management and project planning strategies will help avoid delays, improve ROI, and more accurately predict the long-term cost of initiatives. Planning for unexpected events is a key to success. External factors, such as changing market conditions and evolving government policies are difficult to forecast precisely, so organizations need to build flexibility into project plans to make it easier to adapt to the changes. The report outlines a series of steps executives can take to address these shortcomings and improve their capital-planning processes. Read the full report or take the benchmarking survey and find out how your organization compares.

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  • Rails: The Law of Demeter [duplicate]

    - by user2158382
    This question already has an answer here: Rails: Law of Demeter Confusion 4 answers I am reading a book called Rails AntiPatterns and they talk about using delegation to to avoid breaking the Law of Demeter. Here is their prime example: They believe that calling something like this in the controller is bad (and I agree) @street = @invoice.customer.address.street Their proposed solution is to do the following: class Customer has_one :address belongs_to :invoice def street address.street end end class Invoice has_one :customer def customer_street customer.street end end @street = @invoice.customer_street They are stating that since you only use one dot, you are not breaking the Law of Demeter here. I think this is incorrect, because you are still going through customer to go through address to get the invoice's street. I primarily got this idea from a blog post I read: http://www.dan-manges.com/blog/37 In the blog post the prime example is class Wallet attr_accessor :cash end class Customer has_one :wallet # attribute delegation def cash @wallet.cash end end class Paperboy def collect_money(customer, due_amount) if customer.cash < due_ammount raise InsufficientFundsError else customer.cash -= due_amount @collected_amount += due_amount end end end The blog post states that although there is only one dot customer.cash instead of customer.wallet.cash, this code still violates the Law of Demeter. Now in the Paperboy collect_money method, we don't have two dots, we just have one in "customer.cash". Has this delegation solved our problem? Not at all. If we look at the behavior, a paperboy is still reaching directly into a customer's wallet to get cash out. EDIT I completely understand and agree that this is still a violation and I need to create a method in Wallet called withdraw that handles the payment for me and that I should call that method inside the Customer class. What I don't get is that according to this process, my first example still violates the Law of Demeter because Invoice is still reaching directly into Customer to get the street. Can somebody help me clear the confusion. I have been searching for the past 2 days trying to let this topic sink in, but it is still confusing.

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  • How do I keep a 3D model on the screen in OpenGL?

    - by NoobScratcher
    I'm trying to keep a 3D model on the screen by placing my glDrawElement functions inside the draw function with the declarations at the top of .cpp. When I render the model, the model attaches it self to the current vertex buffer object. This is because my whole graphical user interface is in 2D quads except the window frame. Is there a way to avoid this from happening? or any common causes of this? Creating the file object: int index = IndexAssigner(1, 1); //make a fileobject and store list and the index of that list in a c string ifstream file (list[index].c_str() ); //Make another string //string line; points.push_back(Point()); Point p; int face[4]; Model rendering code: int numfloats = 4; float* point=reinterpret_cast<float*>(&points[0]); int num_bytes=numfloats*sizeof(float); cout << "Size Of Point" << sizeof(Point) << endl; GLuint vertexbuffer; glGenVertexArrays(1, &vao[3]); glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, points.size()*sizeof(points), points.data(), GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, num_bytes, &points[0]); glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(3, GL_FLOAT, points.size(), &points[0]); glEnableClientState(GL_INDEX_ARRAY); glIndexPointer(GL_FLOAT, faces.size(), faces.data()); glEnableVertexAttribArray(0); glDrawElements(GL_QUADS, points.size(), GL_UNSIGNED_INT, points.data()); glDrawElements(GL_QUADS, faces.size(), GL_UNSIGNED_INT, faces.data());

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  • Why is rvalue write in shared memory array serialised?

    - by CJM
    I'm using CUDA 4.0 on a GPU with computing capability 2.1. One of my device functions is the following: device void test(int n, int* itemp) // itemp is shared memory pointer { const int tid = threadIdx.x; const int bdim = blockDim.x; int i, j, k; bool flag = 0; itemp[tid] = 0; for(i=tid; i<n; i+=bdim) { // { code that produces some values of "flag" } } itemp[tid] = flag; } Each thread is checking some conditions and producing a 0/1 flag. Then each thread is writing flag at the tid-th location of a shared int array. The write statement "itemp[tid] = flag;" gets serialized -- though "itemp[tid] = 0;" is not. This is causing huge performance lag which technically should not be there -- I want to avoid it. Please help.

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