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  • Summary of usage policies for website integration of various social media networks?

    - by Dallas
    To cut to the chase... I look at Twitter's usage policy and see limitations on what can and can't be done with their logo. I also see examples of websites that use icons that have been integrated with the look and feel of their own site. Given Twitter's policy, for example, it would appear that legal conversations/agreements would need to take place to do this, especially on a commercial site. I believe it is perfectly acceptable to have a plain text button that simply has the word "Tweet" on it, that has the same functionality. My question is if anyone can provide online (or other) references that attempt to summarize what can and can't be done when integrating various social networks into your own work? The answer I will mark as the correct one will be the one which provides the best resource(s) giving the best summaries of what can and can't be done with specific logos/icons, with a secondary factor being that a variety of social networking sites are addressed in your answer. Before people point to specific questions, I am looking for a well-rounded approach that considers a breadth of networks and considerations. Background: I would like to incorporate social media icons and functionality, but would like to consider what type of modifications can be done without needing to involve lawyers. For example, can I bring in a standard Facebook logo, but incorporate my site color into the logo? Would the answer differ if I maintained their color, but add in a few pixels of another color to transition? I am not saying I want to do this, but rather using it as an example.

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  • How to perform game object smoothing in multiplayer games

    - by spaceOwl
    We're developing an infrastructure to support multiplayer games for our game engine. In simple terms, each client (player) engine sends some pieces of data regarding the relevant game objects at a given time interval. On the receiving end, we step the incoming data to current time (to compensate for latency), followed by a smoothing step (which is the subject of this question). I was wondering how smoothing should be performed ? Currently the algorithm is similar to this: Receive incoming state for an object (position, velocity, acceleration, rotation, custom data like visual properties, etc). Calculate a diff between local object position and the position we have after previous prediction steps. If diff doesn't exceed some threshold value, start a smoothing step: Mark the object's CURRENT POSITION and the TARGET POSITION. Linear interpolate between these values for 0.3 seconds. I wonder if this scheme is any good, or if there is any other common implementation or algorithm that should be used? (For example - should i only smooth out the position? or other values, such as speed, etc) any help will be appreciated.

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  • Quick Fix for GlassFish/MySQL NoPasswordCredential Found

    - by MarkH
    Just the other day, I stood up a GlassFish 3.1.2 server in preparation for a new web app we've developed. Since we're using MySQL as the back-end database, I configured it for MySQL (driver) and created the requisite JDBC resource and supporting connection pool. Pinging the finished pool returned a success, and all was well. Until we fired up the app, that is -- in this case, after a weekend. Funny how things seem to break when you leave them alone for a couple of days. :-) Strangely, the error indicated "No PasswordCredential found". Time to re-check that pool. All the usual properties and values were there (URL, driverClass, serverName, databaseName, portNumber, user, password) and were populated correctly. Yes, the password field, too. And it had pinged successfully. So why the problem? A bit of searching online produced enough relevant material to offer promise. I didn't take notes as I was investigating the cause (note to self), but here were the general steps I took to resolve the issue: First, per some guidance I had found, I tried resetting the password value to nothing (using () for a value). Of course, this didn't fix anything; the database account requires a password. And when I tried to put the value back, GlassFish politely refused. Hmm. I'd seen that some folks created a new pool to replace the "broken" one, and while that did work for them, it seemed to simply side-step the issue. So I deleted the password property - which GlassFish allowed me to do - and restarted the domain. Once I was back in, I re-added the password property and its value, saved it, and pinged...success! But now to the app for the litmus test. The web app worked, and everything and everyone was now happy. Not bad for a Monday.  :-D Hope this helps, Mark

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  • Open Source Highlight: namebench

    - by eddraper
    DNS is a big deal.  Even small incremental changes to improve its performance can yield significant value due to the vast quantity of look-ups required when using the internet.  Until now, It’s always been one of those things I had to kinda take on faith… was my ISP doing a good job?  Are those public DNS server really that much faster?  What about security and privacy concerns? Let me introduce you to namebench.  This is the kinda tool I really love – one that immediately delivers value and is almost over-the-top OCD in its attention to detail. Trust me, this tool is utterly ruthless in it’s quest for getting it right – you’re not left with a big question mark after it presents its data.  The results are conclusive and actionable.  Here’s what is does: It hunts down the fastest DNS servers from your desktop that it can find using thousands of requests.  No, it doesn’t pop up this little dialog in 10 seconds to give you some “off the cuff” answer from a handful of providers.  It takes the better part of 10-15 minutes to run.  When it finishes, it presents you with a veritable horn-o-plenty of data.  Mean response duration, response distribution, bad data,  no stone is left un-turned. Check it out.  You’ll dig it.

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  • Is text-only mode a saving or a problem for battery savings?

    - by Robottinosino
    A friend is flying to the US from Europe and asked me a very thought-provoking question, which I am not remotely able to answer with substance so I am asking it here: How to absolutely maximise battery life on an Ubuntu (laptop) install? do not rush to mark this as duplicate, there is an important point here: does -GNOME- help or worsen battery life? Let me provide some context: The only task he needs to perform is: edit text files in Vim. He is unsure whether running GNOME will drain his battery life more or actually save him some battery life given the smarts of GNOME's power management features like "switch this peripheral to -power save- after X minutes..." (GNOME might just be a configuration front-end for settings that are governed by command-line utils for all I know?) He could perfectly well boot the system in text-only mode and use the automatic 6 virtual consoles for his needs, if that's a saving at all over running tmux (I think so because of all the smart buffering/history/etc the latter does by default?) Exactly how would you advise him to run his laptop during his flight? What I told him already: power off WiFi in the BIOS, not from the "GUI" power off Bluetooth switch off the courtesy light and use low monitor brightness play music off of his phone, not mp3blaster do not use his tiny portable mouse (and do not attach any other USB gimmicks like "screen light", etc) stop development services he will not be using, especially apache2, tomcat, dovecot, postgresql, etc. Potentially: - switch off his cron jobs? (he does an rsync + tar + 7za of his "work in progress" every so often) I think the above is standard stuff one could get off StackExchange, and with many duplicates... the core of this question is, I think: __ will running Ubuntu in text-only mode be a saving in terms of battery life or a problem? why? (provide some technical arguments) __ I think it will be a saving but I am also scared about "other things" detecting and enabling advanced chipset power management features only when some services are started.. and fear these "services" may be off in text-only mode?

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  • How do I cluster strings based on a relation between two strings?

    - by Tom Wijsman
    If you don't know WEKA, you can try a theoretical answer. I don't need literal code/examples... I have a huge data set of strings in which I want to cluster the strings to find the most related ones, these could as well be seen as duplicate. I already have a set of couples of string for which I know that they are duplicate to each other, so, now I want to do some data mining on those two sets. The result I'm looking for is a system that would return me the possible most relevant couples of strings for which we don't know yet that they are duplicates, I believe that I need clustering for this, which type? Note that I want to base myself on word occurrence comparison, not on interpretation or meaning. Here is an example of two string of which we know they are duplicate (in our vision on them): The weather is really cold and it is raining. It is raining and the weather is really cold. Now, the following strings also exist (most to least relevant, ignoring stop words): Is the weather really that cold today? Rainy days are awful. I see the sunshine outside. The software would return the following two strings as most relevant, which aren't known to be duplicate: The weather is really cold and it is raining. Is the weather really that cold today? Then, I would mark that as duplicate or not duplicate and it would present me with another couple. How do I go to implement this in the most efficient way that I can apply to a large data set?

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  • Creating movement path displays in a top-down 2d RTS

    - by nihohit
    My game is a top-down 2d RTS coded in C# using SFML's libraries. I want that during unit selection, a unit will display it's movement path on the map. Currently, after the path is computed as a list of directions ({left, up,down, down, down, left}, as an example), it's sent to the graphical component to create it's UI equivalent, and here I'm having some problems. current, these I've checked three ways to do it: compute the size of the image (in the example above it'll be a 3*2 rectangle) and create an invisible rectangle, and then go over the directions list and mark each spot with a visible point, so as to get a continous line. This system is slightly problematic because of the amount of large images that I need to save, but mostly because I have a lot of fine detail onscreen, and a continous line obstructs the view. again, compute the size of the image, but now create several (let's say 4) invisible images of that size, and then instead of a single continous line I'll switch between the four images, in each will appear only a fourth of the spots, in a way which creates a path animation. This is nicer on the eye, but here the memory demands, and the amount of time needed to compute each such image-loop is significant. Just create a list of single markers, each on a different spot on the path. This is very quick & easy on memory, but too sparse. Is there a simple or resource-light system to create path-animations?

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  • Any benefit of /home Ubuntu partition

    - by nightcrawler
    I want to have dual OS of Win8 & Ubuntu 12.10. Provided that Ubuntu can access ntfs partition of Windows but same can't be said about Windows this leads to a question mark on the significance of having /home partition while installing Ubuntu. As far as I know /swap & / are the two partitions directly used by Ubuntu to store programs, installation & stuff while the documents/media resides in /home. Now because Ubuntu releases are more frequent than Windows & updates needs backup & relate stuff, so I came to decision to not to use /home at all, rather keep all my documents/media in ntfs, which would be untouched while upgrading Ubuntu as Win updates are once in a decade! Is my thinking correct? If yes, what would be the minimum space I should allot to /home plus how much I should allot to / one must know that I plan to use heavy applications like Maple, Matlab & Sagemath on Ubuntu.

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  • Should this be written in C or php?

    - by user1867842
    This is my code; it speaks for itself on what I'm trying to do. <?php define("html","<html>"); define("htmlEnd","</html>"); etc... etc... ?> What I'm trying to do is make a wrapper for html's tags so they won't be needed anymore. But I can't get any of the attributes for html elements to be defined in PHP. This again speaks for itself; I don't know any other way of saying this. I guess how would I make another mark-up language like HTML without any tags but still keep everything about HTML is what I'm trying to say. My idea is for preventing XSS. For example, creating a special framework for the website itself that way there is no way any malicious attacker can guess because they know the HTML or PHP. I just don't want to make my website or something, and then my website gets hacked. Or if I make a website for someone and the website gets hacked. I am going to look like a unprofessional web developer. And what if I never get a job again.

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  • Type of AI to tackle this problem?

    - by user1154277
    I posted this on stackoverflow but want to get your recommendations as well as a user on overflow recommended I post it here. I'm going to say from the beginning that I am not a programmer, I have a cursory knowledge of different types of AI and am just a businessman building a web app. Anyways, the web app I am investing in to develop is for a hobby of mine. There are many part manufacturers, product manufacturers, upgrade and addon manufacturers etc. for hardware/products in this hobby's industry. Currently, I am in the process of building a crowd sourced platform for people who are knowledgeable to go in and mark up compatibility between those parts as its not always clear cut if they are for example: Manufacturer A makes a "A" class product, and manufacturer B makes upgrade/part that generally goes with class "A" products, but is for one reason or another not compatible with Manufacturer A's particular "A" class product. However, a good chunk (60%-70%) of the products/parts in the database can have their compatibility inferenced by their properties, For example: Part 1 is type "A" with "X" mm receiver and part 2 is also Type "A" with "X" mm interface and thus the two parts are compatible.. or Part 1 is a 8mm gear, thus all bushings of 8mm from any manufacturer is compatible with part 1. Further more, all gears can only have compatibility relationships in the database with bushing and gear boxes, but there can be no meaningful compatibility between a gear and a rail, or receiver since those parts don't interface. Now what I want is an AI to be able to learn from the decisions of the crowdsourced platform community and be able to inference compatibility for new parts/products based on their tagged attributes, what type of part they are etc. What would be the best form of AI to tackle this? I was thinking a Expert System, but explicitly engineering all of the knowledge rules would be daunting because of the complex relations between literally tens of thousands of parts, hundreds of part types and many manufacturers. Would a ANN (neural network) be ideal to learn from the many inputs/decisions of the crowdsource platform users? Any help/input is much appreciated.

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  • How do web servers enforce the same-origin policy?

    - by BBnyc
    I'm diving deeper into developing RESTful APIs and have so far worked with a few different frameworks to achieve this. Of course I've run into the same-origin policy, and now I'm wondering how web servers (rather than web browsers) enforce it. From what I understand, some enforcing seems to happen on the browser's end (e.g., honoring a Access-Control-Allow-Origin header received from a server). But what about the server? For example, let's say a web server is hosting a Javascript web app that accesses an API, also hosted on that server. I assume that server would enforce the same-origin policy --- so that only the javascript that is hosted on that server would be allowed to access the API. This would prevent someone else from writing a javascript client for that API and hosting it on another site, right? So how would a web server be able to stop a malicious client that would try to make AJAX requests to its api endpoints while claiming to be running javascript that originated from that same web server? What's the way most popular servers (Apache, nginx) protect against this kind of attack? Or is my understanding of this somehow off the mark? Or is the cross-origin policy only enforced on the client end?

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  • Dependency injection: At what point am I allowed to create a new object?

    - by Gaz_Edge
    I am refactoring a PHP application, and I am trying to do has much dependency injection (DI) as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. I'm refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects, that is, use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? It's looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be OK as they are factory classes, but are there some rules to stick to when using a factory pattern and DI, or am I going way off the mark here?

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  • Multisystem Script won't work! "Syntax error:redirection unexpected" Worked 2 days ago?

    - by user74005
    this is my first question. I use Multisystem all of the time and have installed it on both Kubuntu and Ubuntu and have used it with no issues. I wiped my hard drive to try some new OSs I'm now using the exact same OS (Ubuntu 12.05) I used to load my USB stick to begin with and now I'm getting this ridiculous syntax error. I know the script is correct, I'm following the exact same steps I used to get to this point and I'm getting different results ?!?! I'm very confused by this. I have no clue how to begin addressing this issue. I get the same syntax error on Kubuntu now too, which did have multisystem installed. I run "sh install-depot-multisystem.sh" and get "Syntax error:redirection unexpected", this worked literally 2 days ago. The only thing that has changed is my face has grown some more facial hair and my head hurts from bangin it against the wall over this issue. The OS is exactly the same, the script is the same; but now it won't install. I'm lost and really hoping someone can help. Append Just to append to this a bit https://lists.ubuntu.com/archives/ub...er/000264.html I needed to do a chmod 777 on the script, I'm still getting a syntax error on Kubuntu...but it did install successfully. I'll mark this as resovled! Thanks anyway, I'll try to spruse up on my Linux skills.

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  • How can we add arch specific conflicts tag when building .deb package?

    - by Sphopale
    We are trying to build multi-arch supported i386 .deb package. There are two .deb packages build on i386 X1 & X2 (X2 is a subset of X1 binaries). X1 <- X2 conflict each other when installing . Only one .deb package can be installed at any instance. We similarly have binaries on xa64 arch. Again on xa64, there are two .deb packages X1 & X2 (X2 is a subset of X1 binaries). X1 <- X2 conflict each other when installing . Only one .deb package can be installed at any instance. In case of multi-arch i386 .deb package,i386 .deb packages (X1 & X2) can be installed on xa64 along side with 64bit (X1 & X2) However I see that when installing X1:i386 & X1:amd64 can co-exist However, it throws conflict error when trying to install X1:i386 & X2:amd64 In short, Can we mark package to conflict based on arch Conflict: X2:i386 X1:i386 package should only conflict with X2:i386 & allow other packages to co-exist X1:amd64 package should only conflict with X2:amd64 & allow other packages to co-exist X1:i386 can co-exist with X1:amd64 OR X2:amd64 X2:i386 can co-exist with X1:amd64 OR X2:amd64 Thanks for your reply

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  • Oracle Open World 2012?????

    - by Liu Maclean(???)
    Oracle Open World 2012?????: ???.. Oracle OpenWorld 2012 sessions????:Search Content Catalog for Oracle OpenWorld 2012 sessions ?????????session??? Open World 2012??: Larry ??Exadata X3 OOW 2012???Exadata X3,?? X3-2 ?Expansion Rack X3-2?X3-8 Exadata X3????:http://www.oracle.com/us/products/database/exadata/overview/index.html  ORACLE EXADATA Database MACHINE X3-8 sheetORACLE EXADATA Database MACHINE X3-2 sheet Exadata X3-2???????: X3-2?compute db node?????????8?Intel Xeon E5-2690??? ??????????12????16?,???33%????? ???96GB???128GB,????256GB ??????????50% X3-2 cell node??????????????Intel Xeon ??????flash card flash card??????4?,??flash card?????????40%? ???X3-2???22.4TB?flash ,??????flash????????????????????,???10????? CPU???6?,????????Intel Xeon model ????????X2-2??,???600GB???????3TB?????? ??Exadata X3-2?????????,??????????1/4?????,1/8????????????????? Exadata X3-8???????: X3-8???X2-8?????,???X3-8??????????X3-2??,??X3-8?????22.4TB?????? ???CEO??  Engineered to Work Together OOW????? Oracle Open World 2012 ????? Open World 2012 ??:http://www.oracle.com/openworld/index.htmlOpen World 2012 ????:http://www.oracle.com/openworld/register/packages/index.html ??: Sept. 30 – Oct. 4, 2012 9?30?? 10?4? ??:Moscone Center, San Francisco (747 Howard Street, San Francisco, California 94103). ?????Mark Hurd??OOW 2012: How big is oow OOW 2012?????????: Focus On Database Technologies Focus On Real Application Clusters Focus On Exadata Focus On Oracle Database Appliance Focus On Oracle Database Application Development Focus On Oracle Database Security Focus On Big Data Focus On Data Warehousing Focus On High Availability Focus On Oracle Enterprise Manager Cloud Control 12c (and Private Cloud) Focus On Oracle Spatial and Graph Focus On Oracle Database Utilities Focus On Oracle Database Upgrade Focus On Oracle Database Private Cloud Focus On .Net Focus On Oracle Database on Windows Focus On Engineered Systems Focus On Sunday Users Forum

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  • Learn about the Exciting New WebCenter Content 11.1.1.8 Features by Attending the Advisor Webcast on November 21st!

    - by AlanBoucher
    Have you been looking for a place to store your content securely and in an organized fashion, while needing to access it while you are on the go? Well you can!  Learn about the new Mobile App for WebCenter Content 11.1.1.8 along with other exciting new features by attending the Advisor Webcast called WebCenter Content 11.1.1.8 Overview and Support Information. November 21, 2013 at 11 am ET, 10 am CT, 9 am MT, 8 am PT, 5:00 pm, Europe Time (Paris, GMT+01:00) This one-hour session is recommended for technical and functional users who have installed or will install WebCenter Content 11.1.1.8 or would just like more information on the latest release. TOPICS WILL INCLUDE: Overview of new features and enhancements Installation of the new Content UI Upgrading from older WebCenter Content versions Support issues including latest patches Roadmap of proposed additional features REGISTER NOW and mark your Calendar:1. Event address for attendees: https://oracleaw.webex.com/oracleaw/onstage/g.php?d=590991341&t=a2. Register for the meeting.Once the host approves your request, you will receive a confirmation email with instructions for joining the meeting.

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  • The [2] table entry '[3]' has no associated entry in the Media table. (error 2602)

    - by derekf
    Coworker started getting the above message in the event log and as dialog during install.  Argument [2] was File and argument [3] was a specific file. Error dialog read   Product: (app name) -- The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2602. Package was a vendor-provided MSI that had been installed administratively, and then a patch (.msp) applied to the administrative install point. With some digging we found that the MSI still had the entries in the media table pointing at the CAB files, and that there were several files at the end of the sequence that did not have corresponding entries in the Media table (last sequence 990 in Media table, last entry in File table had sequence 994).  Attributes on files in the File table all had the msidbFileAttributesCompressed (&16384) attribute set, so they were all expecting to be within the CAB files, but since this was an admin install there were no CAB files. Resolved by clearing the Media table (replace with a single entry: Disk ID 1, LastSequence 994) and going through the file table and subtracting 8192 from each entry to mark files as not compressed.  Tested and worked.

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  • Dependency Injection: What point am I allowed to create a new object?

    - by Gaz_Edge
    I am refactoring a php application and I am trying to do has much dependency injection as possible. I feel like I've got a good grasp of how it works, and I can certainly see my classes becoming a lot leaner and more robust. Im refactoring so that I can inject a dependency rather than create a new object within the class, but at some point I am going to have to create some objects i.e. use the dreaded new keyword. The problem I have now run into is at what point can I actually create new objects? Its looking like I'll end up at a top level class, creating loads of new objects as there is no where else to go. This feels wrong. I've read some blogs that use factory classes to create all the objects, and then you inject the factory into other classes. You can then call the factory methods, and the factory creates the new object for you. My concern with doing this is now my factory classes are going to be a new free-for-all! I guess this may be ok as they are factory classes, but are there some rules to stick to when using factory pattern and DI, or am I going way off the mark here.

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  • Problems extracting information from RSS feed description field

    - by Graeme
    Hi, I've built an iPhone application using the parsing code from the TopSongs sample iPhone application. I've hit a problem though - the feed I'm trying to parse data from doesn't have a separate field for every piece of information (i.e. if it was for a feed about dogs, all the information such as dog type, dog age and dog price is contained in the feed. However, the TopSongs app relies on information having its own tags, so instead of using it uses and . So my question is this. How do I extract this information from the description field so that it can be parsed using the TopSongs parser? Can you somehow extract the dog age, price and type information using Yahoo Pipes and use that RSS feed for the feed? Or is there code that I can add to do it in application? Update: To view the code of my application parser (based on the TopSongs Core Data Apple provided application, see below. Here's a sample of one item from the the actual RSS feed I'm using (the description is longer, and has status,size, and a couple of other fields, but they're all formatted the same.: <item> <title>MOE, MARGRET STREET</title> <description> <b>District/Region:</b>&nbsp;REGION 09</br><b>Location:</b>&nbsp;MOE</br><b>Name:</b>&nbsp;MARGRET STREET</br></description> <pubDate>Thu,11 Mar 2010 05:43:03 GMT</pubDate> <guid>1266148</guid> </item> /* File: iTunesRSSImporter.m Abstract: Downloads, parses, and imports the iTunes top songs RSS feed into Core Data. Version: 1.1 Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in consideration of your agreement to the following terms, and your use, installation, modification or redistribution of this Apple software constitutes acceptance of these terms. If you do not agree with these terms, please do not use, install, modify or redistribute this Apple software. In consideration of your agreement to abide by the following terms, and subject to these terms, Apple grants you a personal, non-exclusive license, under Apple's copyrights in this original Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the Apple Software, with or without modifications, in source and/or binary forms; provided that if you redistribute the Apple Software in its entirety and without modifications, you must retain this notice and the following text and disclaimers in all such redistributions of the Apple Software. Neither the name, trademarks, service marks or logos of Apple Inc. may be used to endorse or promote products derived from the Apple Software without specific prior written permission from Apple. Except as expressly stated in this notice, no other rights or licenses, express or implied, are granted by Apple herein, including but not limited to any patent rights that may be infringed by your derivative works or by other works in which the Apple Software may be incorporated. The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Copyright (C) 2009 Apple Inc. All Rights Reserved. */ #import "iTunesRSSImporter.h" #import "Song.h" #import "Category.h" #import "CategoryCache.h" #import <libxml/tree.h> // Function prototypes for SAX callbacks. This sample implements a minimal subset of SAX callbacks. // Depending on your application's needs, you might want to implement more callbacks. static void startElementSAX(void *context, const xmlChar *localname, const xmlChar *prefix, const xmlChar *URI, int nb_namespaces, const xmlChar **namespaces, int nb_attributes, int nb_defaulted, const xmlChar **attributes); static void endElementSAX(void *context, const xmlChar *localname, const xmlChar *prefix, const xmlChar *URI); static void charactersFoundSAX(void *context, const xmlChar *characters, int length); static void errorEncounteredSAX(void *context, const char *errorMessage, ...); // Forward reference. The structure is defined in full at the end of the file. static xmlSAXHandler simpleSAXHandlerStruct; // Class extension for private properties and methods. @interface iTunesRSSImporter () @property BOOL storingCharacters; @property (nonatomic, retain) NSMutableData *characterBuffer; @property BOOL done; @property BOOL parsingASong; @property NSUInteger countForCurrentBatch; @property (nonatomic, retain) Song *currentSong; @property (nonatomic, retain) NSURLConnection *rssConnection; @property (nonatomic, retain) NSDateFormatter *dateFormatter; // The autorelease pool property is assign because autorelease pools cannot be retained. @property (nonatomic, assign) NSAutoreleasePool *importPool; @end static double lookuptime = 0; @implementation iTunesRSSImporter @synthesize iTunesURL, delegate, persistentStoreCoordinator; @synthesize rssConnection, done, parsingASong, storingCharacters, currentSong, countForCurrentBatch, characterBuffer, dateFormatter, importPool; - (void)dealloc { [iTunesURL release]; [characterBuffer release]; [currentSong release]; [rssConnection release]; [dateFormatter release]; [persistentStoreCoordinator release]; [insertionContext release]; [songEntityDescription release]; [theCache release]; [super dealloc]; } - (void)main { self.importPool = [[NSAutoreleasePool alloc] init]; if (delegate && [delegate respondsToSelector:@selector(importerDidSave:)]) { [[NSNotificationCenter defaultCenter] addObserver:delegate selector:@selector(importerDidSave:) name:NSManagedObjectContextDidSaveNotification object:self.insertionContext]; } done = NO; self.dateFormatter = [[[NSDateFormatter alloc] init] autorelease]; [dateFormatter setDateStyle:NSDateFormatterLongStyle]; [dateFormatter setTimeStyle:NSDateFormatterNoStyle]; // necessary because iTunes RSS feed is not localized, so if the device region has been set to other than US // the date formatter must be set to US locale in order to parse the dates [dateFormatter setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"US"] autorelease]]; self.characterBuffer = [NSMutableData data]; NSURLRequest *theRequest = [NSURLRequest requestWithURL:iTunesURL]; // create the connection with the request and start loading the data rssConnection = [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; // This creates a context for "push" parsing in which chunks of data that are not "well balanced" can be passed // to the context for streaming parsing. The handler structure defined above will be used for all the parsing. // The second argument, self, will be passed as user data to each of the SAX handlers. The last three arguments // are left blank to avoid creating a tree in memory. context = xmlCreatePushParserCtxt(&simpleSAXHandlerStruct, self, NULL, 0, NULL); if (rssConnection != nil) { do { [[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]]; } while (!done); } // Display the total time spent finding a specific object for a relationship NSLog(@"lookup time %f", lookuptime); // Release resources used only in this thread. xmlFreeParserCtxt(context); self.characterBuffer = nil; self.dateFormatter = nil; self.rssConnection = nil; self.currentSong = nil; [theCache release]; theCache = nil; NSError *saveError = nil; NSAssert1([insertionContext save:&saveError], @"Unhandled error saving managed object context in import thread: %@", [saveError localizedDescription]); if (delegate && [delegate respondsToSelector:@selector(importerDidSave:)]) { [[NSNotificationCenter defaultCenter] removeObserver:delegate name:NSManagedObjectContextDidSaveNotification object:self.insertionContext]; } if (self.delegate != nil && [self.delegate respondsToSelector:@selector(importerDidFinishParsingData:)]) { [self.delegate importerDidFinishParsingData:self]; } [importPool release]; self.importPool = nil; } - (NSManagedObjectContext *)insertionContext { if (insertionContext == nil) { insertionContext = [[NSManagedObjectContext alloc] init]; [insertionContext setPersistentStoreCoordinator:self.persistentStoreCoordinator]; } return insertionContext; } - (void)forwardError:(NSError *)error { if (self.delegate != nil && [self.delegate respondsToSelector:@selector(importer:didFailWithError:)]) { [self.delegate importer:self didFailWithError:error]; } } - (NSEntityDescription *)songEntityDescription { if (songEntityDescription == nil) { songEntityDescription = [[NSEntityDescription entityForName:@"Song" inManagedObjectContext:self.insertionContext] retain]; } return songEntityDescription; } - (CategoryCache *)theCache { if (theCache == nil) { theCache = [[CategoryCache alloc] init]; theCache.managedObjectContext = self.insertionContext; } return theCache; } - (Song *)currentSong { if (currentSong == nil) { currentSong = [[Song alloc] initWithEntity:self.songEntityDescription insertIntoManagedObjectContext:self.insertionContext]; } return currentSong; } #pragma mark NSURLConnection Delegate methods // Forward errors to the delegate. - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { [self performSelectorOnMainThread:@selector(forwardError:) withObject:error waitUntilDone:NO]; // Set the condition which ends the run loop. done = YES; } // Called when a chunk of data has been downloaded. - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data { // Process the downloaded chunk of data. xmlParseChunk(context, (const char *)[data bytes], [data length], 0); } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { // Signal the context that parsing is complete by passing "1" as the last parameter. xmlParseChunk(context, NULL, 0, 1); context = NULL; // Set the condition which ends the run loop. done = YES; } #pragma mark Parsing support methods static const NSUInteger kImportBatchSize = 20; - (void)finishedCurrentSong { parsingASong = NO; self.currentSong = nil; countForCurrentBatch++; // Periodically purge the autorelease pool and save the context. The frequency of this action may need to be tuned according to the // size of the objects being parsed. The goal is to keep the autorelease pool from growing too large, but // taking this action too frequently would be wasteful and reduce performance. if (countForCurrentBatch == kImportBatchSize) { [importPool release]; self.importPool = [[NSAutoreleasePool alloc] init]; NSError *saveError = nil; NSAssert1([insertionContext save:&saveError], @"Unhandled error saving managed object context in import thread: %@", [saveError localizedDescription]); countForCurrentBatch = 0; } } /* Character data is appended to a buffer until the current element ends. */ - (void)appendCharacters:(const char *)charactersFound length:(NSInteger)length { [characterBuffer appendBytes:charactersFound length:length]; } - (NSString *)currentString { // Create a string with the character data using UTF-8 encoding. UTF-8 is the default XML data encoding. NSString *currentString = [[[NSString alloc] initWithData:characterBuffer encoding:NSUTF8StringEncoding] autorelease]; [characterBuffer setLength:0]; return currentString; } @end #pragma mark SAX Parsing Callbacks // The following constants are the XML element names and their string lengths for parsing comparison. // The lengths include the null terminator, to ensure exact matches. static const char *kName_Item = "item"; static const NSUInteger kLength_Item = 5; static const char *kName_Title = "title"; static const NSUInteger kLength_Title = 6; static const char *kName_Category = "category"; static const NSUInteger kLength_Category = 9; static const char *kName_Itms = "itms"; static const NSUInteger kLength_Itms = 5; static const char *kName_Artist = "description"; static const NSUInteger kLength_Artist = 7; static const char *kName_Album = "description"; static const NSUInteger kLength_Album = 6; static const char *kName_ReleaseDate = "releasedate"; static const NSUInteger kLength_ReleaseDate = 12; /* This callback is invoked when the importer finds the beginning of a node in the XML. For this application, out parsing needs are relatively modest - we need only match the node name. An "item" node is a record of data about a song. In that case we create a new Song object. The other nodes of interest are several of the child nodes of the Song currently being parsed. For those nodes we want to accumulate the character data in a buffer. Some of the child nodes use a namespace prefix. */ static void startElementSAX(void *parsingContext, const xmlChar *localname, const xmlChar *prefix, const xmlChar *URI, int nb_namespaces, const xmlChar **namespaces, int nb_attributes, int nb_defaulted, const xmlChar **attributes) { iTunesRSSImporter *importer = (iTunesRSSImporter *)parsingContext; // The second parameter to strncmp is the name of the element, which we known from the XML schema of the feed. // The third parameter to strncmp is the number of characters in the element name, plus 1 for the null terminator. if (prefix == NULL && !strncmp((const char *)localname, kName_Item, kLength_Item)) { importer.parsingASong = YES; } else if (importer.parsingASong && ( (prefix == NULL && (!strncmp((const char *)localname, kName_Title, kLength_Title) || !strncmp((const char *)localname, kName_Category, kLength_Category))) || ((prefix != NULL && !strncmp((const char *)prefix, kName_Itms, kLength_Itms)) && (!strncmp((const char *)localname, kName_Artist, kLength_Artist) || !strncmp((const char *)localname, kName_Album, kLength_Album) || !strncmp((const char *)localname, kName_ReleaseDate, kLength_ReleaseDate))) )) { importer.storingCharacters = YES; } } /* This callback is invoked when the parse reaches the end of a node. At that point we finish processing that node, if it is of interest to us. For "item" nodes, that means we have completed parsing a Song object. We pass the song to a method in the superclass which will eventually deliver it to the delegate. For the other nodes we care about, this means we have all the character data. The next step is to create an NSString using the buffer contents and store that with the current Song object. */ static void endElementSAX(void *parsingContext, const xmlChar *localname, const xmlChar *prefix, const xmlChar *URI) { iTunesRSSImporter *importer = (iTunesRSSImporter *)parsingContext; if (importer.parsingASong == NO) return; if (prefix == NULL) { if (!strncmp((const char *)localname, kName_Item, kLength_Item)) { [importer finishedCurrentSong]; } else if (!strncmp((const char *)localname, kName_Title, kLength_Title)) { importer.currentSong.title = importer.currentString; } else if (!strncmp((const char *)localname, kName_Category, kLength_Category)) { double before = [NSDate timeIntervalSinceReferenceDate]; Category *category = [importer.theCache categoryWithName:importer.currentString]; double delta = [NSDate timeIntervalSinceReferenceDate] - before; lookuptime += delta; importer.currentSong.category = category; } } else if (!strncmp((const char *)prefix, kName_Itms, kLength_Itms)) { if (!strncmp((const char *)localname, kName_Artist, kLength_Artist)) { NSString *string = importer.currentSong.artist; NSArray *strings = [string componentsSeparatedByString: @", "]; //importer.currentSong.artist = importer.currentString; } else if (!strncmp((const char *)localname, kName_Album, kLength_Album)) { importer.currentSong.album = importer.currentString; } else if (!strncmp((const char *)localname, kName_ReleaseDate, kLength_ReleaseDate)) { NSString *dateString = importer.currentString; importer.currentSong.releaseDate = [importer.dateFormatter dateFromString:dateString]; } } importer.storingCharacters = NO; } /* This callback is invoked when the parser encounters character data inside a node. The importer class determines how to use the character data. */ static void charactersFoundSAX(void *parsingContext, const xmlChar *characterArray, int numberOfCharacters) { iTunesRSSImporter *importer = (iTunesRSSImporter *)parsingContext; // A state variable, "storingCharacters", is set when nodes of interest begin and end. // This determines whether character data is handled or ignored. if (importer.storingCharacters == NO) return; [importer appendCharacters:(const char *)characterArray length:numberOfCharacters]; } /* A production application should include robust error handling as part of its parsing implementation. The specifics of how errors are handled depends on the application. */ static void errorEncounteredSAX(void *parsingContext, const char *errorMessage, ...) { // Handle errors as appropriate for your application. NSCAssert(NO, @"Unhandled error encountered during SAX parse."); } // The handler struct has positions for a large number of callback functions. If NULL is supplied at a given position, // that callback functionality won't be used. Refer to libxml documentation at http://www.xmlsoft.org for more information // about the SAX callbacks. static xmlSAXHandler simpleSAXHandlerStruct = { NULL, /* internalSubset */ NULL, /* isStandalone */ NULL, /* hasInternalSubset */ NULL, /* hasExternalSubset */ NULL, /* resolveEntity */ NULL, /* getEntity */ NULL, /* entityDecl */ NULL, /* notationDecl */ NULL, /* attributeDecl */ NULL, /* elementDecl */ NULL, /* unparsedEntityDecl */ NULL, /* setDocumentLocator */ NULL, /* startDocument */ NULL, /* endDocument */ NULL, /* startElement*/ NULL, /* endElement */ NULL, /* reference */ charactersFoundSAX, /* characters */ NULL, /* ignorableWhitespace */ NULL, /* processingInstruction */ NULL, /* comment */ NULL, /* warning */ errorEncounteredSAX, /* error */ NULL, /* fatalError //: unused error() get all the errors */ NULL, /* getParameterEntity */ NULL, /* cdataBlock */ NULL, /* externalSubset */ XML_SAX2_MAGIC, // NULL, startElementSAX, /* startElementNs */ endElementSAX, /* endElementNs */ NULL, /* serror */ }; Thanks.

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  • WPF MVVM: Convention over Configuration for ResourceDictionary ?

    - by Jeffrey Knight
    Update In the wiki spirit of StackOverflow, here's an update: I spiked Joe White's IValueConverter suggestion below. It works like a charm. I've written a "quickstart" example of this that automates the mapping of ViewModels-Views using some cheap string replacement. If no View is found to represent the ViewModel, it defaults to an "Under Construction" page. I'm dubbing this approach "WPF MVVM White" since it was Joe White's idea. Here are a couple screenshots. The first image is a case of "[SomeControlName]ViewModel" has a corresponding "[SomeControlName]View", based on pure naming convention. The second is a case where the ModelView doesn't have any views to represent it. No more ResourceDictionaries with long ViewModel to View mappings. It's pure naming convention now. I'm hosting a download of the project here: http://rootsilver.com/files/Mvvm.White.Quickstart.zip I'll follow up with a longer blog post walk through. Original Post I read Josh Smith's fantastic MSDN article on WPF MVVM over the weekend. It's destined to be a cult classic. It took me a while to wrap my head around the magic of asking WPF to render the ViewModel. It's like saying "Here's a class, WPF. Go figure out which UI to use to present it." For those who missed this magic, WPF can do this by looking up the View for ModelView in the ResourceDictionary mapping and pulling out the corresponding View. (Scroll down to Figure 10 Supplying a View ). The first thing that jumps out at me immediately is that there's already a strong naming convention of: classNameView ("View" suffix) classNameViewModel ("ViewModel" suffix) My question is: Since the ResourceDictionary can be manipulated programatically, I"m wondering if anyone has managed to Regex.Replace the whole thing away, so the lookup is automatic, and any new View/ViewModels get resolved by virtue of their naming convention? [Edit] What I'm imagining is a hook/interception into ResourceDictionary. ... Also considering a method at startup that uses interop to pull out *View$ and *ViewModel$ class names to build the DataTemplate dictionary in code: //build list foreach .... String.Format("<DataTemplate DataType=\"{x:Type vm:{0} }\"><v:{1} /></DataTemplate>", ...)

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  • CodePlex Daily Summary for Saturday, March 13, 2010

    CodePlex Daily Summary for Saturday, March 13, 2010New Projects[Experiment] vczh DBUI: EXPERIMENT. Auto UI adaptor for a specified data base[SAMPLE PROJECT] Branch and Patch with GIT: I'll paste more here later...BlogPress: This web application provides a content management system. Coot: Facebook Photos Screensaver.DotNetNuke® JDMenu: dnnJDMenu makes it easy to use the open source JDMenu component in your DotNetNuke skin.DotNetNuke® RadRotator: dnnRadRotator makes it easy to add telerik RadRotator functionality to your site or custom module. Licensing permits anyone to use the components ...DotNetNuke® RadTabStrip: DNNRadTabStrip makes it easy to add telerik RadTabStrip functionality to your module or skin. Licensing permits anyone to use the components (incl...DotNetNuke® RadTreeView: DNNRadTreeView makes it easy to add telerik RadTreeView functionality to your module or skin. Licensing permits anyone to use the components (incl...DotNetNuke® Skin Garden: A DotNetNuke Design Challenge skin package submitted to the "Out of the box" category by Mark Allan of DnnGarden. Concise and semantic HTML 5 stru...ElmasFC: Elmas Facebook CheckerFront Callback Protocol: Front Callback Protocol make it easier for developers to create a network application in the .Net Language. It provide the flexibility of using TCP...Glass UI: A Windows Forms Control Library built specifically for Aero Glass. This will consist of existing controls, modified to render on glass, as well as ...Guitarist Tools: Some tools for guitarists.HomeUX: HomeUX is home control software featuring a Silverlight-based touch screen user interface.Homework Helper: Homework Helper help students to train simpler homework like "What's the name of the capital of France?" - Question - Answear based. It's made i...IGNOU Mini Project Allocation: A mini project allocation system.Images Compiler: Images Compiler is pretty small wpf application for users who want to resize, rename, disable colors... for too much images in very short time. It...InstitutionManagementSystem: Institution Management System prototypeManagedCv: ManagedCv is the library for C#/VB/ to use the OpenCV librarymanagement joint ownership: Application pour la gestion des actions réalisées au sein d’une copropriété. Application for management actions within a joint ownershipMapWindow6: MapWindow 6.0 is an open source geographic information system (GIS) and library of geospatial software development tools for .NET, written in C#. T...Morris Auto: Morris Auto is a social application build templateMouse control with finger detection: The aim of this project is to design an application for recognition of the movement of a finger through a webcam and then control the mouse. The pr...ORAYLIS BI.Quality: ORAYLIS BI.Quality makes it easier to develop BI Solutions in an agile environment. It adapts Unit Tests to BI Development. Propositional Framework: Different sales propositions are presented to the user using data collected from marketing intelligence, browser history or user behaviour as they ...ServStop: ServStop is a .NET application that makes it easy to stop several system services at once. Now you don't have to change startup types or stop them ...shatkotha web portal: source code of web portal shatkothaSurvey and Registration tools: Two Silverlight tools for add Survey and Registration in your websiteTable Storage Backup & Restore for Windows Azure: Allows various backup & restore options for Windows Azure Table Storage accounts: - Backup from one storage account to another - Backup a storag...Topsy Lib: This project provides wrapper methods to call Topsy's web services from C#.twNowplaying: twNowplaying is a small and handy utility that allows you to tweet your currently playing track from Spotify to Twitter. Followed by the #twNowplay...XOM: XOM: Xml Object Mapper Automatically populate your objects with data from XML via an XML map. Never do this again: if(e.GetElementsByTagName("us...YS Utils: The library contains set of useful classes which may solve common tasks for different applications.ZabViewer: CS ProjectNew ReleasesAppFabric Caching Admin Tool: AppFabric Caching Admin Tool (0.8): System Requirements:.NET 4.0 RC AppFabric Caching Beta2 Test On:Win 7 (64x)ASP.Net Routing Configuration: mal.Web.Routing v0.9.2.0: mal.Web.Routing v0.9.2.0DotNetNuke IM Module of Facebook Like Messenger: DNN IM Module of Facebook Like Messenger: Empower DNN Website with a 1-to-1 Chat Solution named Free Facebook Messenger Style Web Chat Bar of 123 Web Messenger. 1. If you need to use the c...DotNetNuke® Form and List (formerly User Defined Table): 05.01.02: Form and List 05.01.02 (Release Candidate 2)5.1.2 will be the next stabilzation release. Major Highlights fixed Cancel action in a form, it don't ...DotNetNuke® JDMenu: DNN jdMenu 1.0.0: dnnJDMenu makes it easy to use the open source JDMenu component in your DotNetNuke skin. Many thanks to Jonathan Sharp of Outwest Media for creati...DotNetNuke® RadTabStrip: DNNRadTabstrip 1.0.0: DNNRadTabStrip makes it easy to add telerik RadTabStrip functionality to your module or skin. Licensing permits anyone to use the components (inclu...DotNetNuke® RadTreeView: DNNRadTreeView 1.0.0: DNNRadTreeView makes it easy to create skins which use the Telerik RadTreeview functionality. Licensing permits anyone (including designers) to use...DotNetNuke® Skin Garden: Garden Package 1.0.0: A DotNetNuke Design Challenge skin package submitted to the "Out of the box" category by Mark Allan of DnnGarden. Concise and semantic HTML 5 struc...ElmasFC: Elmas FC: This porgram is checking your facebook account automaticly.Free DotNetNuke IM of 123 Web Messenger -- Web-based Friend List: Free Download DNN IM Module and Source Code: 123 Web Messenger offers free DotNetNuke Instant Messaging to help you embed a IM Software into DNN Website by integrating 123 Web Messenger with D...Free Silverlight & WPF Chart Control - Visifire: Visifire SL and WPF Charts 3.0.4 Released: Hi, Today we have released the final version of Visifire v3.0.4 which contains the following major features: * Zooming * Step Line chart ...Home Access Plus+: v3.1.0.0: Version 3.1.0.0 Release Problem with this release, get Version 3.1.1.1 Change Log: Fixed ampersand issue Added Unzip Features Added Help Desk ...Home Access Plus+: v3.1.1.1: Version 3.1.1.1 Release Change Log: Fixed the Help Desk File Changes: ~/App_Data/Tickets.xml ~/bin/CHS Extranet.dll ~/bin/CHS Extranet.pdbHomework Helper: Homework Helper 1.0: The first release of Homework Helper. It got basic functionality. Check the Documentation or press F1 while using the program.Homework Helper: Homework Helper v1.0: This is the latest version of Homework Helper. Just a few updates since the latest one (a couple of minutes ago). Now it saves your settings! Instr...IBCSharp: IBCSharp 1.02: What IBCSharp 1.02.zip unzips to: http://i39.tinypic.com/28hz8m1.png Note: The above solution has MSTest, Typemock Isolator, and Microsoft CHESS c...InfoService: InfoService v1.5 RC 1: InfoService Release Canidate Please note this is a RC. It should be stable, but i can't guarantee that! So use it on your own risk. Please read Pl...IntX: IntX 0.9.3.3: Fixed issue #7100IronRuby: 1.0 RC3: The IronRuby team is pleased to announce version 1.0 RC3! As IronRuby approaches the final 1.0, these RCs will contain crucial bug fixes and enhanc...MAISGestão: LayerDiagram (pdf): This is the final version of the layer diagramMapWindow6: MapWindow 6.0 msi (March 12): After some significant trouble with svn, this site represents a test of using Mercurial for our version control. Hopefully the choice of this new ...MSBuild Mercurial Tasks: 0.2.0 Beta: This release realises the Scenario 2 and provides two MSBuild tasks: HgCommit and HgPush. This task allows to create a new changeset in the current...NLog - Advanced .NET Logging: NLog 2.0 preview 1: This is very experimental first build of NLog from 2.0 branch is available for download. It’s not alpha, beta or even gamma, just a preview of upco...Open NFe: Fonte DANFE v1.9.5: Código-fonte para a versão 1.9.5 do DANFEOpiConsole (XNA): OpiConsole 0.3: OpiConsole 0.3 OpiConsole includes: * PC & Xbox support. * Default commands (cvar, quit etc.) * Ability to add custom commands. *...ORAYLIS BI.Quality: Release 1.0.0: Release 1.0.0Pcap.Net: Pcap.Net 0.5.0 (38141): Pcap.Net - March 2010 Release Pcap.Net is a .NET wrapper for WinPcap written in C++/CLI and C#. It Features almost all WinPcap features and include...PhysX.Net: PhysX.Net 0.12.0.0 Beta 1: This is beta release of 0.12.0.0 for people to test and provide feedback on. It targets 2.8.3.21 of PhysXPólya: Pólya 2010 03 13 alpha: Pólya is a collection of generic data structures; as generic as C#/.Net allows them to be. In this first release the focus has been on some fundam...Prolog.NET: Prolog.NET 1.0 Beta 1.3: Installer includes: primary Prolog.NET assembly Prolog.NET Workbench Prolog.NET Scheduler sample application PrologTest console applicatio...Propositional Framework: USP: The initial code drop was based on the Autocomplete demo and the neural network approach used by Jeff Heaton (@ http://www.heatonresearch.com/) - e...Protocol Transition with BizTalk: Source: Stable buildRoTwee: RoTwee (7.1.0.0): Now picture of your friend is shown in RoTwee. Place mouse cursor to the tweet !ServStop: 0.5.0.0: Initial Release Contents of ServStop0500.zip ServStop.exe 0.5.0.0 Initial Release. 32,768 bytes. Other files None. Source code available on "...SkeinLibManaged: Release 1.0.0.0 (Beta): This is the compiled DLL with XML documentation, so there should be plenty of context sensitive help and Intellisense. This is the Release version...sPWadmin: pwAdmin v0.9a: Added: LiveChat Plugin Shows the latest 150 chat messages from "/Your PW Server/logservice/logs/world2.chat" Refresh chat every 5 seconds Allow...sPWadmin: pwAdmin v0.9b: Some minor fixes to style, layout & different browser support Merged the forms in server configuration tab to a single form that can now save mul...Topsy Lib: Initial release: Initial Debug and Release versions.twNowplaying: twNowplaying: Press the Twitter icon to get started, don't forget to submit bugs to the issue tracker. What's new This release has some minor UI fixes.twNowplaying: twNowplaying Alpha 1.0: Press the Twitter icon to get started, don't forget to submit bugs to the issue tracker. Thank you , and enjoy! =)VCC: Latest build, v2.1.30312.0: Automatic drop of latest buildWPF Dialogs: Version 0.1.3: The FolderBrowseDialog / FolderBrowseDialog - Deutsch was improved and extended.XOM: XOM 0.1A: Just a release of the code I have so far. In order to get your objects to work, you need to create an XML file to define your objects. Here is a ...Xpress - ASP.NET MVC 个人博客程序: xpress2.1.1.0312.beta: 最新beta版,注意:此版本和2.1.0不兼容 更改内容: 将主题文件发放在 Views 文件夹下 主题文件支持强类型Model 主题资源文件放在Resouces目录下YS Utils: V 1.0.0.0: This is first release. The YSUtils library contains first set of classes. ZIP files contains documentation.Most Popular ProjectsMetaSharpWBFS ManagerRawrAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)ASP.NET Ajax LibraryASP.NETMicrosoft SQL Server Community & SamplesMost Active ProjectsRawrN2 CMSBlogEngine.NETFasterflect - A Fast and Simple Reflection APIpatterns & practices – Enterprise LibraryFarseer Physics EngineSharePoint Team-MailerCaliburn: An Application Framework for WPF and SilverlightCalcium: A modular application toolset leveraging PrismjQuery Library for SharePoint Web Services

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  • Flow-Design Cheat Sheet &ndash; Part I, Notation

    - by Ralf Westphal
    You want to avoid the pitfalls of object oriented design? Then this is the right place to start. Use Flow-Oriented Analysis (FOA) and –Design (FOD or just FD for Flow-Design) to understand a problem domain and design a software solution. Flow-Orientation as described here is related to Flow-Based Programming, Event-Based Programming, Business Process Modelling, and even Event-Driven Architectures. But even though “thinking in flows” is not new, I found it helpful to deviate from those precursors for several reasons. Some aim at too big systems for the average programmer, some are concerned with only asynchronous processing, some are even not very much concerned with programming at all. What I was looking for was a design method to help in software projects of any size, be they large or tiny, involing synchronous or asynchronous processing, being local or distributed, running on the web or on the desktop or on a smartphone. That´s why I took ideas from all of the above sources and some additional and came up with Event-Based Components which later got repositioned and renamed to Flow-Design. In the meantime this has generated some discussion (in the German developer community) and several teams have started to work with Flow-Design. Also I´ve conducted quite some trainings using Flow-Orientation for design. The results are very promising. Developers find it much easier to design software using Flow-Orientation than OOAD-based object orientation. Since Flow-Orientation is moving fast and is not covered completely by a single source like a book, demand has increased for at least an overview of the current state of its notation. This page is trying to answer this demand by briefly introducing/describing every notational element as well as their translation into C# source code. Take this as a cheat sheet to put next to your whiteboard when designing software. However, please do not expect any explanation as to the reasons behind Flow-Design elements. Details on why Flow-Design at all and why in this specific way you´ll find in the literature covering the topic. Here´s a resource page on Flow-Design/Event-Based Components, if you´re able to read German. Notation Connected Functional Units The basic element of any FOD are functional units (FU): Think of FUs as some kind of software code block processing data. For the moment forget about classes, methods, “components”, assemblies or whatever. See a FU as an abstract piece of code. Software then consists of just collaborating FUs. I´m using circles/ellipses to draw FUs. But if you like, use rectangles. Whatever suites your whiteboard needs best.   The purpose of FUs is to process input and produce output. FUs are transformational. However, FUs are not called and do not call other FUs. There is no dependency between FUs. Data just flows into a FU (input) and out of it (output). From where and where to is of no concern to a FU.   This way FUs can be concatenated in arbitrary ways:   Each FU can accept input from many sources and produce output for many sinks:   Flows Connected FUs form a flow with a start and an end. Data is entering a flow at a source, and it´s leaving it through a sink. Think of sources and sinks as special FUs which conntect wires to the environment of a network of FUs.   Wiring Details Data is flowing into/out of FUs through wires. This is to allude to electrical engineering which since long has been working with composable parts. Wires are attached to FUs usings pins. They are the entry/exit points for the data flowing along the wires. Input-/output pins currently need not be drawn explicitly. This is to keep designing on a whiteboard simple and quick.   Data flowing is of some type, so wires have a type attached to them. And pins have names. If there is only one input pin and output pin on a FU, though, you don´t need to mention them. The default is Process for a single input pin, and Result for a single output pin. But you´re free to give even single pins different names.   There is a shortcut in use to address a certain pin on a destination FU:   The type of the wire is put in parantheses for two reasons. 1. This way a “no-type” wire can be easily denoted, 2. this is a natural way to describe tuples of data.   To describe how much data is flowing, a star can be put next to the wire type:   Nesting – Boards and Parts If more than 5 to 10 FUs need to be put in a flow a FD starts to become hard to understand. To keep diagrams clutter free they can be nested. You can turn any FU into a flow: This leads to Flow-Designs with different levels of abstraction. A in the above illustration is a high level functional unit, A.1 and A.2 are lower level functional units. One of the purposes of Flow-Design is to be able to describe systems on different levels of abstraction and thus make it easier to understand them. Humans use abstraction/decomposition to get a grip on complexity. Flow-Design strives to support this and make levels of abstraction first class citizens for programming. You can read the above illustration like this: Functional units A.1 and A.2 detail what A is supposed to do. The whole of A´s responsibility is decomposed into smaller responsibilities A.1 and A.2. FU A thus does not do anything itself anymore! All A is responsible for is actually accomplished by the collaboration between A.1 and A.2. Since A now is not doing anything anymore except containing A.1 and A.2 functional units are devided into two categories: boards and parts. Boards are just containing other functional units; their sole responsibility is to wire them up. A is a board. Boards thus depend on the functional units nested within them. This dependency is not of a functional nature, though. Boards are not dependent on services provided by nested functional units. They are just concerned with their interface to be able to plug them together. Parts are the workhorses of flows. They contain the real domain logic. They actually transform input into output. However, they do not depend on other functional units. Please note the usage of source and sink in boards. They correspond to input-pins and output-pins of the board.   Implicit Dependencies Nesting functional units leads to a dependency tree. Boards depend on nested functional units, they are the inner nodes of the tree. Parts are independent, they are the leafs: Even though dependencies are the bane of software development, Flow-Design does not usually draw these dependencies. They are implicitly created by visually nesting functional units. And they are harmless. Boards are so simple in their functionality, they are little affected by changes in functional units they are depending on. But functional units are implicitly dependent on more than nested functional units. They are also dependent on the data types of the wires attached to them: This is also natural and thus does not need to be made explicit. And it pertains mainly to parts being dependent. Since boards don´t do anything with regard to a problem domain, they don´t care much about data types. Their infrastructural purpose just needs types of input/output-pins to match.   Explicit Dependencies You could say, Flow-Orientation is about tackling complexity at its root cause: that´s dependencies. “Natural” dependencies are depicted naturally, i.e. implicitly. And whereever possible dependencies are not even created. Functional units don´t know their collaborators within a flow. This is core to Flow-Orientation. That makes for high composability of functional units. A part is as independent of other functional units as a motor is from the rest of the car. And a board is as dependend on nested functional units as a motor is on a spark plug or a crank shaft. With Flow-Design software development moves closer to how hardware is constructed. Implicit dependencies are not enough, though. Sometimes explicit dependencies make designs easier – as counterintuitive this might sound. So FD notation needs a ways to denote explicit dependencies: Data flows along wires. But data does not flow along dependency relations. Instead dependency relations represent service calls. Functional unit C is depending on/calling services on functional unit S. If you want to be more specific, name the services next to the dependency relation: Although you should try to stay clear of explicit dependencies, they are fundamentally ok. See them as a way to add another dimension to a flow. Usually the functionality of the independent FU (“Customer repository” above) is orthogonal to the domain of the flow it is referenced by. If you like emphasize this by using different shapes for dependent and independent FUs like above. Such dependencies can be used to link in resources like databases or shared in-memory state. FUs can not only produce output but also can have side effects. A common pattern for using such explizit dependencies is to hook a GUI into a flow as the source and/or the sink of data: Which can be shortened to: Treat FUs others depend on as boards (with a special non-FD API the dependent part is connected to), but do not embed them in a flow in the diagram they are depended upon.   Attributes of Functional Units Creation and usage of functional units can be modified with attributes. So far the following have shown to be helpful: Singleton: FUs are by default multitons. FUs in the same of different flows with the same name refer to the same functionality, but to different instances. Think of functional units as objects that get instanciated anew whereever they appear in a design. Sometimes though it´s helpful to reuse the same instance of a functional unit; this is always due to valuable state it holds. Signify this by annotating the FU with a “(S)”. Multiton: FUs on which others depend are singletons by default. This is, because they usually are introduced where shared state comes into play. If you want to change them to be a singletons mark them with a “(M)”. Configurable: Some parts need to be configured before the can do they work in a flow. Annotate them with a “(C)” to have them initialized before any data items to be processed by them arrive. Do not assume any order in which FUs are configured. How such configuration is happening is an implementation detail. Entry point: In each design there needs to be a single part where “it all starts”. That´s the entry point for all processing. It´s like Program.Main() in C# programs. Mark the entry point part with an “(E)”. Quite often this will be the GUI part. How the entry point is started is an implementation detail. Just consider it the first FU to start do its job.   Patterns / Standard Parts If more than a single wire is attached to an output-pin that´s called a split (or fork). The same data is flowing on all of the wires. Remember: Flow-Designs are synchronous by default. So a split does not mean data is processed in parallel afterwards. Processing still happens synchronously and thus one branch after another. Do not assume any specific order of the processing on the different branches after the split.   It is common to do a split and let only parts of the original data flow on through the branches. This effectively means a map is needed after a split. This map can be implicit or explicit.   Although FUs can have multiple input-pins it is preferrable in most cases to combine input data from different branches using an explicit join: The default output of a join is a tuple of its input values. The default behavior of a join is to output a value whenever a new input is received. However, to produce its first output a join needs an input for all its input-pins. Other join behaviors can be: reset all inputs after an output only produce output if data arrives on certain input-pins

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  • The Shift: how Orchard painlessly shifted to document storage, and how it’ll affect you

    - by Bertrand Le Roy
    We’ve known it all along. The storage for Orchard content items would be much more efficient using a document database than a relational one. Orchard content items are composed of parts that serialize naturally into infoset kinds of documents. Storing them as relational data like we’ve done so far was unnatural and requires the data for a single item to span multiple tables, related through 1-1 relationships. This means lots of joins in queries, and a great potential for Select N+1 problems. Document databases, unfortunately, are still a tough sell in many places that prefer the more familiar relational model. Being able to x-copy Orchard to hosters has also been a basic constraint in the design of Orchard. Combine those with the necessity at the time to run in medium trust, and with license compatibility issues, and you’ll find yourself with very few reasonable choices. So we went, a little reluctantly, for relational SQL stores, with the dream of one day transitioning to document storage. We have played for a while with the idea of building our own document storage on top of SQL databases, and Sébastien implemented something more than decent along those lines, but we had a better way all along that we didn’t notice until recently… In Orchard, there are fields, which are named properties that you can add dynamically to a content part. Because they are so dynamic, we have been storing them as XML into a column on the main content item table. This infoset storage and its associated API are fairly generic, but were only used for fields. The breakthrough was when Sébastien realized how this existing storage could give us the advantages of document storage with minimal changes, while continuing to use relational databases as the substrate. public bool CommercialPrices { get { return this.Retrieve(p => p.CommercialPrices); } set { this.Store(p => p.CommercialPrices, value); } } This code is very compact and efficient because the API can infer from the expression what the type and name of the property are. It is then able to do the proper conversions for you. For this code to work in a content part, there is no need for a record at all. This is particularly nice for site settings: one query on one table and you get everything you need. This shows how the existing infoset solves the data storage problem, but you still need to query. Well, for those properties that need to be filtered and sorted on, you can still use the current record-based relational system. This of course continues to work. We do however provide APIs that make it trivial to store into both record properties and the infoset storage in one operation: public double Price { get { return Retrieve(r => r.Price); } set { Store(r => r.Price, value); } } This code looks strikingly similar to the non-record case above. The difference is that it will manage both the infoset and the record-based storages. The call to the Store method will send the data in both places, keeping them in sync. The call to the Retrieve method does something even cooler: if the property you’re looking for exists in the infoset, it will return it, but if it doesn’t, it will automatically look into the record for it. And if that wasn’t cool enough, it will take that value from the record and store it into the infoset for the next time it’s required. This means that your data will start automagically migrating to infoset storage just by virtue of using the code above instead of the usual: public double Price { get { return Record.Price; } set { Record.Price = value; } } As your users browse the site, it will get faster and faster as Select N+1 issues will optimize themselves away. If you preferred, you could still have explicit migration code, but it really shouldn’t be necessary most of the time. If you do already have code using QueryHints to mitigate Select N+1 issues, you might want to reconsider those, as with the new system, you’ll want to avoid joins that you don’t need for filtering or sorting, further optimizing your queries. There are some rare cases where the storage of the property must be handled differently. Check out this string[] property on SearchSettingsPart for example: public string[] SearchedFields { get { return (Retrieve<string>("SearchedFields") ?? "") .Split(new[] {',', ' '}, StringSplitOptions.RemoveEmptyEntries); } set { Store("SearchedFields", String.Join(", ", value)); } } The array of strings is transformed by the property accessors into and from a comma-separated list stored in a string. The Retrieve and Store overloads used in this case are lower-level versions that explicitly specify the type and name of the attribute to retrieve or store. You may be wondering what this means for code or operations that look directly at the database tables instead of going through the new infoset APIs. Even if there is a record, the infoset version of the property will win if it exists, so it is necessary to keep the infoset up-to-date. It’s not very complicated, but definitely something to keep in mind. Here is what a product record looks like in Nwazet.Commerce for example: And here is the same data in the infoset: The infoset is stored in Orchard_Framework_ContentItemRecord or Orchard_Framework_ContentItemVersionRecord, depending on whether the content type is versionable or not. A good way to find what you’re looking for is to inspect the record table first, as it’s usually easier to read, and then get the item record of the same id. Here is the detailed XML document for this product: <Data> <ProductPart Inventory="40" Price="18" Sku="pi-camera-box" OutOfStockMessage="" AllowBackOrder="false" Weight="0.2" Size="" ShippingCost="null" IsDigital="false" /> <ProductAttributesPart Attributes="" /> <AutoroutePart DisplayAlias="camera-box" /> <TitlePart Title="Nwazet Pi Camera Box" /> <BodyPart Text="[...]" /> <CommonPart CreatedUtc="2013-09-10T00:39:00Z" PublishedUtc="2013-09-14T01:07:47Z" /> </Data> The data is neatly organized under each part. It is easy to see how that document is all you need to know about that content item, all in one table. If you want to modify that data directly in the database, you should be careful to do it in both the record table and the infoset in the content item record. In this configuration, the record is now nothing more than an index, and will only be used for sorting and filtering. Of course, it’s perfectly fine to mix record-backed properties and record-less properties on the same part. It really depends what you think must be sorted and filtered on. In turn, this potentially simplifies migrations considerably. So here it is, the great shift of Orchard to document storage, something that Orchard has been designed for all along, and that we were able to implement with a satisfying and surprising economy of resources. Expect this code to make its way into the 1.8 version of Orchard when that’s available.

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  • Windows Azure Service Bus Scatter-Gather Implementation

    - by Alan Smith
    One of the more challenging enterprise integration patterns that developers may wish to implement is the Scatter-Gather pattern. In this article I will show the basic implementation of a scatter-gather pattern using the topic-subscription model of the windows azure service bus. I’ll be using the implementation in demos, and also as a lab in my training courses, and the pattern will also be included in the next release of my free e-book the “Windows Azure Service Bus Developer Guide”. The Scatter-Gather pattern answers the following scenario. How do you maintain the overall message flow when a message needs to be sent to multiple recipients, each of which may send a reply? Use a Scatter-Gather that broadcasts a message to multiple recipients and re-aggregates the responses back into a single message. The Enterprise Integration Patterns website provides a description of the Scatter-Gather pattern here.   The scatter-gather pattern uses a composite of the publish-subscribe channel pattern and the aggregator pattern. The publish-subscribe channel is used to broadcast messages to a number of receivers, and the aggregator is used to gather the response messages and aggregate them together to form a single message. Scatter-Gather Scenario The scenario for this scatter-gather implementation is an application that allows users to answer questions in a poll based voting scenario. A poll manager application will be used to broadcast questions to users, the users will use a voting application that will receive and display the questions and send the votes back to the poll manager. The poll manager application will receive the users’ votes and aggregate them together to display the results. The scenario should be able to scale to support a large number of users.   Scatter-Gather Implementation The diagram below shows the overall architecture for the scatter-gather implementation.       Messaging Entities Looking at the scatter-gather pattern diagram it can be seen that the topic-subscription architecture is well suited for broadcasting a message to a number of subscribers. The poll manager application can send the question messages to a topic, and each voting application can receive the question message on its own subscription. The static limit of 2,000 subscriptions per topic in the current release means that 2,000 voting applications can receive question messages and take part in voting. The vote messages can then be sent to the poll manager application using a queue. The voting applications will send their vote messages to the queue, and the poll manager will receive and process the vote messages. The questions topic and answer queue are created using the Windows Azure Developer Portal. Each instance of the voting application will create its own subscription in the questions topic when it starts, allowing the question messages to be broadcast to all subscribing voting applications. Data Contracts Two simple data contracts will be used to serialize the questions and votes as brokered messages. The code for these is shown below.   [DataContract] public class Question {     [DataMember]     public string QuestionText { get; set; } }     To keep the implementation of the voting functionality simple and focus on the pattern implementation, the users can only vote yes or no to the questions.   [DataContract] public class Vote {     [DataMember]     public string QuestionText { get; set; }       [DataMember]     public bool IsYes { get; set; } }     Poll Manager Application The poll manager application has been implemented as a simple WPF application; the user interface is shown below. A question can be entered in the text box, and sent to the topic by clicking the Add button. The topic and subscriptions used for broadcasting the messages are shown in a TreeView control. The questions that have been broadcast and the resulting votes are shown in a ListView control. When the application is started any existing subscriptions are cleared form the topic, clients are then created for the questions topic and votes queue, along with background workers for receiving and processing the vote messages, and updating the display of subscriptions.   public MainWindow() {     InitializeComponent();       // Create a new results list and data bind it.     Results = new ObservableCollection<Result>();     lsvResults.ItemsSource = Results;       // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Clear out any old subscriptions.     NamespaceManager = new NamespaceManager(serviceBusUri, credentials);     IEnumerable<SubscriptionDescription> subs =         NamespaceManager.GetSubscriptions(AccountDetails.ScatterGatherTopic);     foreach (SubscriptionDescription sub in subs)     {         NamespaceManager.DeleteSubscription(sub.TopicPath, sub.Name);     }       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Create the topic and queue clients.     ScatterGatherTopicClient =         factory.CreateTopicClient(AccountDetails.ScatterGatherTopic);     ScatterGatherQueueClient =         factory.CreateQueueClient(AccountDetails.ScatterGatherQueue);       // Start the background worker threads.     VotesBackgroundWorker = new BackgroundWorker();     VotesBackgroundWorker.DoWork += new DoWorkEventHandler(ReceiveMessages);     VotesBackgroundWorker.RunWorkerAsync();       SubscriptionsBackgroundWorker = new BackgroundWorker();     SubscriptionsBackgroundWorker.DoWork += new DoWorkEventHandler(UpdateSubscriptions);     SubscriptionsBackgroundWorker.RunWorkerAsync(); }     When the poll manager user nters a question in the text box and clicks the Add button a question message is created and sent to the topic. This message will be broadcast to all the subscribing voting applications. An instance of the Result class is also created to keep track of the votes cast, this is then added to an observable collection named Results, which is data-bound to the ListView control.   private void btnAddQuestion_Click(object sender, RoutedEventArgs e) {     // Create a new result for recording votes.     Result result = new Result()     {         Question = txtQuestion.Text     };     Results.Add(result);       // Send the question to the topic     Question question = new Question()     {         QuestionText = result.Question     };     BrokeredMessage msg = new BrokeredMessage(question);     ScatterGatherTopicClient.Send(msg);       txtQuestion.Text = ""; }     The Results class is implemented as follows.   public class Result : INotifyPropertyChanged {     public string Question { get; set; }       private int m_YesVotes;     private int m_NoVotes;       public event PropertyChangedEventHandler PropertyChanged;       public int YesVotes     {         get { return m_YesVotes; }         set         {             m_YesVotes = value;             NotifyPropertyChanged("YesVotes");         }     }       public int NoVotes     {         get { return m_NoVotes; }         set         {             m_NoVotes = value;             NotifyPropertyChanged("NoVotes");         }     }       private void NotifyPropertyChanged(string prop)     {         if(PropertyChanged != null)         {             PropertyChanged(this, new PropertyChangedEventArgs(prop));         }     } }     The INotifyPropertyChanged interface is implemented so that changes to the number of yes and no votes will be updated in the ListView control. Receiving the vote messages from the voting applications is done asynchronously, using a background worker thread.   // This runs on a background worker. private void ReceiveMessages(object sender, DoWorkEventArgs e) {     while (true)     {         // Receive a vote message from the queue         BrokeredMessage msg = ScatterGatherQueueClient.Receive();         if (msg != null)         {             // Deserialize the message.             Vote vote = msg.GetBody<Vote>();               // Update the results.             foreach (Result result in Results)             {                 if (result.Question.Equals(vote.QuestionText))                 {                     if (vote.IsYes)                     {                         result.YesVotes++;                     }                     else                     {                         result.NoVotes++;                     }                     break;                 }             }               // Mark the message as complete.             msg.Complete();         }       } }     When a vote message is received, the result that matches the vote question is updated with the vote from the user. The message is then marked as complete. A second background thread is used to update the display of subscriptions in the TreeView, with a dispatcher used to update the user interface. // This runs on a background worker. private void UpdateSubscriptions(object sender, DoWorkEventArgs e) {     while (true)     {         // Get a list of subscriptions.         IEnumerable<SubscriptionDescription> subscriptions =             NamespaceManager.GetSubscriptions(AccountDetails.ScatterGatherTopic);           // Update the user interface.         SimpleDelegate setQuestion = delegate()         {             trvSubscriptions.Items.Clear();             TreeViewItem topicItem = new TreeViewItem()             {                 Header = AccountDetails.ScatterGatherTopic             };               foreach (SubscriptionDescription subscription in subscriptions)             {                 TreeViewItem subscriptionItem = new TreeViewItem()                 {                     Header = subscription.Name                 };                 topicItem.Items.Add(subscriptionItem);             }             trvSubscriptions.Items.Add(topicItem);               topicItem.ExpandSubtree();         };         this.Dispatcher.BeginInvoke(DispatcherPriority.Send, setQuestion);           Thread.Sleep(3000);     } }       Voting Application The voting application is implemented as another WPF application. This one is more basic, and allows the user to vote “Yes” or “No” for the questions sent by the poll manager application. The user interface for that application is shown below. When an instance of the voting application is created it will create a subscription in the questions topic using a GUID as the subscription name. The application can then receive copies of every question message that is sent to the topic. Clients for the new subscription and the votes queue are created, along with a background worker to receive the question messages. The voting application is set to receiving mode, meaning it is ready to receive a question message from the subscription.   public MainWindow() {     InitializeComponent();       // Set the mode to receiving.     IsReceiving = true;       // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Create a subcription for this instance     NamespaceManager mgr = new NamespaceManager(serviceBusUri, credentials);     string subscriptionName = Guid.NewGuid().ToString();     mgr.CreateSubscription(AccountDetails.ScatterGatherTopic, subscriptionName);       // Create the subscription and queue clients.     ScatterGatherSubscriptionClient = factory.CreateSubscriptionClient         (AccountDetails.ScatterGatherTopic, subscriptionName);     ScatterGatherQueueClient =         factory.CreateQueueClient(AccountDetails.ScatterGatherQueue);       // Start the background worker thread.     BackgroundWorker = new BackgroundWorker();     BackgroundWorker.DoWork += new DoWorkEventHandler(ReceiveMessages);     BackgroundWorker.RunWorkerAsync(); }     I took the inspiration for creating the subscriptions in the voting application from the chat application that uses topics and subscriptions blogged by Ovais Akhter here. The method that receives the question messages runs on a background thread. If the application is in receive mode, a question message will be received from the subscription, the question will be displayed in the user interface, the voting buttons enabled, and IsReceiving set to false to prevent more questing from being received before the current one is answered.   // This runs on a background worker. private void ReceiveMessages(object sender, DoWorkEventArgs e) {     while (true)     {         if (IsReceiving)         {             // Receive a question message from the topic.             BrokeredMessage msg = ScatterGatherSubscriptionClient.Receive();             if (msg != null)             {                 // Deserialize the message.                 Question question = msg.GetBody<Question>();                   // Update the user interface.                 SimpleDelegate setQuestion = delegate()                 {                     lblQuestion.Content = question.QuestionText;                     btnYes.IsEnabled = true;                     btnNo.IsEnabled = true;                 };                 this.Dispatcher.BeginInvoke(DispatcherPriority.Send, setQuestion);                 IsReceiving = false;                   // Mark the message as complete.                 msg.Complete();             }         }         else         {             Thread.Sleep(1000);         }     } }     When the user clicks on the Yes or No button, the btnVote_Click method is called. This will create a new Vote data contract with the appropriate question and answer and send the message to the poll manager application using the votes queue. The user voting buttons are then disabled, the question text cleared, and the IsReceiving flag set to true to allow a new message to be received.   private void btnVote_Click(object sender, RoutedEventArgs e) {     // Create a new vote.     Vote vote = new Vote()     {         QuestionText = (string)lblQuestion.Content,         IsYes = ((sender as Button).Content as string).Equals("Yes")     };       // Send the vote message.     BrokeredMessage msg = new BrokeredMessage(vote);     ScatterGatherQueueClient.Send(msg);       // Update the user interface.     lblQuestion.Content = "";     btnYes.IsEnabled = false;     btnNo.IsEnabled = false;     IsReceiving = true; }     Testing the Application In order to test the application, an instance of the poll manager application is started; the user interface is shown below. As no instances of the voting application have been created there are no subscriptions present in the topic. When an instance of the voting application is created the subscription will be displayed in the poll manager. Now that a voting application is subscribing, a questing can be sent from the poll manager application. When the message is sent to the topic, the voting application will receive the message and display the question. The voter can then answer the question by clicking on the appropriate button. The results of the vote are updated in the poll manager application. When two more instances of the voting application are created, the poll manager will display the new subscriptions. More questions can then be broadcast to the voting applications. As the question messages are queued up in the subscription for each voting application, the users can answer the questions in their own time. The vote messages will be received by the poll manager application and aggregated to display the results. The screenshots of the applications part way through voting are shown below. The messages for each voting application are queued up in sequence on the voting application subscriptions, allowing the questions to be answered at different speeds by the voters.

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  • Loosely coupled .NET Cache Provider using Dependency Injection

    - by Rhames
    I have recently been reading the excellent book “Dependency Injection in .NET”, written by Mark Seemann. I do not generally buy software development related books, as I never seem to have the time to read them, but I have found the time to read Mark’s book, and it was time well spent I think. Reading the ideas around Dependency Injection made me realise that the Cache Provider code I wrote about earlier (see http://geekswithblogs.net/Rhames/archive/2011/01/10/using-the-asp.net-cache-to-cache-data-in-a-model.aspx) could be refactored to use Dependency Injection, which should produce cleaner code. The goals are to: Separate the cache provider implementation (using the ASP.NET data cache) from the consumers (loose coupling). This will also mean that the dependency on System.Web for the cache provider does not ripple down into the layers where it is being consumed (such as the domain layer). Provide a decorator pattern to allow a consumer of the cache provider to be implemented separately from the base consumer (i.e. if we have a base repository, we can decorate this with a caching version). Although I used the term repository, in reality the cache consumer could be just about anything. Use constructor injection to provide the Dependency Injection, with a suitable DI container (I use Castle Windsor). The sample code for this post is available on github, https://github.com/RobinHames/CacheProvider.git ICacheProvider In the sample code, the key interface is ICacheProvider, which is in the domain layer. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace CacheDiSample.Domain 5: { 6: public interface ICacheProvider<T> 7: { 8: T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 9: IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry); 10: } 11: }   This interface contains two methods to retrieve data from the cache, either as a single instance or as an IEnumerable. the second paramerter is of type Func<T>. This is the method used to retrieve data if nothing is found in the cache. The ASP.NET implementation of the ICacheProvider interface needs to live in a project that has a reference to system.web, typically this will be the root UI project, or it could be a separate project. The key thing is that the domain or data access layers do not need system.web references adding to them. In my sample MVC application, the CacheProvider is implemented in the UI project, in a folder called “CacheProviders”: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Caching; 6: using CacheDiSample.Domain; 7:   8: namespace CacheDiSample.CacheProvider 9: { 10: public class CacheProvider<T> : ICacheProvider<T> 11: { 12: public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 13: { 14: return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry); 15: } 16:   17: public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 18: { 19: return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry); 20: } 21:   22: #region Helper Methods 23:   24: private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry) 25: { 26: U value; 27: if (!TryGetValue<U>(key, out value)) 28: { 29: value = retrieveData(); 30: if (!absoluteExpiry.HasValue) 31: absoluteExpiry = Cache.NoAbsoluteExpiration; 32:   33: if (!relativeExpiry.HasValue) 34: relativeExpiry = Cache.NoSlidingExpiration; 35:   36: HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value); 37: } 38: return value; 39: } 40:   41: private bool TryGetValue<U>(string key, out U value) 42: { 43: object cachedValue = HttpContext.Current.Cache.Get(key); 44: if (cachedValue == null) 45: { 46: value = default(U); 47: return false; 48: } 49: else 50: { 51: try 52: { 53: value = (U)cachedValue; 54: return true; 55: } 56: catch 57: { 58: value = default(U); 59: return false; 60: } 61: } 62: } 63:   64: #endregion 65:   66: } 67: }   The FetchAndCache helper method checks if the specified cache key exists, if it does not, the Func<U> retrieveData method is called, and the results are added to the cache. Using Castle Windsor to register the cache provider In the MVC UI project (my application root), Castle Windsor is used to register the CacheProvider implementation, using a Windsor Installer: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain; 6: using CacheDiSample.CacheProvider; 7:   8: namespace CacheDiSample.WindsorInstallers 9: { 10: public class CacheInstaller : IWindsorInstaller 11: { 12: public void Install(IWindsorContainer container, IConfigurationStore store) 13: { 14: container.Register( 15: Component.For(typeof(ICacheProvider<>)) 16: .ImplementedBy(typeof(CacheProvider<>)) 17: .LifestyleTransient()); 18: } 19: } 20: }   Note that the cache provider is registered as a open generic type. Consuming a Repository I have an existing couple of repository interfaces defined in my domain layer: IRepository.cs 1: using System; 2: using System.Collections.Generic; 3:   4: using CacheDiSample.Domain.Model; 5:   6: namespace CacheDiSample.Domain.Repositories 7: { 8: public interface IRepository<T> 9: where T : EntityBase 10: { 11: T GetById(int id); 12: IList<T> GetAll(); 13: } 14: }   IBlogRepository.cs 1: using System; 2: using CacheDiSample.Domain.Model; 3:   4: namespace CacheDiSample.Domain.Repositories 5: { 6: public interface IBlogRepository : IRepository<Blog> 7: { 8: Blog GetByName(string name); 9: } 10: }   These two repositories are implemented in the DataAccess layer, using Entity Framework to retrieve data (this is not important though). One important point is that in the BaseRepository implementation of IRepository, the methods are virtual. This will allow the decorator to override them. The BlogRepository is registered in a RepositoriesInstaller, again in the MVC UI project. 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15: container.Register(Component.For<IBlogRepository>() 16: .ImplementedBy<BlogRepository>() 17: .LifestyleTransient() 18: .DependsOn(new 19: { 20: nameOrConnectionString = "BloggingContext" 21: })); 22: } 23: } 24: }   Now I can inject a dependency on the IBlogRepository into a consumer, such as a controller in my sample code: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:   7: using CacheDiSample.Domain.Repositories; 8: using CacheDiSample.Domain.Model; 9:   10: namespace CacheDiSample.Controllers 11: { 12: public class HomeController : Controller 13: { 14: private readonly IBlogRepository blogRepository; 15:   16: public HomeController(IBlogRepository blogRepository) 17: { 18: if (blogRepository == null) 19: throw new ArgumentNullException("blogRepository"); 20:   21: this.blogRepository = blogRepository; 22: } 23:   24: public ActionResult Index() 25: { 26: ViewBag.Message = "Welcome to ASP.NET MVC!"; 27:   28: var blogs = blogRepository.GetAll(); 29:   30: return View(new Models.HomeModel { Blogs = blogs }); 31: } 32:   33: public ActionResult About() 34: { 35: return View(); 36: } 37: } 38: }   Consuming the Cache Provider via a Decorator I used a Decorator pattern to consume the cache provider, this means my repositories follow the open/closed principle, as they do not require any modifications to implement the caching. It also means that my controllers do not have any knowledge of the caching taking place, as the DI container will simply inject the decorator instead of the root implementation of the repository. The first step is to implement a BlogRepository decorator, with the caching logic in it. Note that this can reside in the domain layer, as it does not require any knowledge of the data access methods. BlogRepositoryWithCaching.cs 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5:   6: using CacheDiSample.Domain.Model; 7: using CacheDiSample.Domain; 8: using CacheDiSample.Domain.Repositories; 9:   10: namespace CacheDiSample.Domain.CacheDecorators 11: { 12: public class BlogRepositoryWithCaching : IBlogRepository 13: { 14: // The generic cache provider, injected by DI 15: private ICacheProvider<Blog> cacheProvider; 16: // The decorated blog repository, injected by DI 17: private IBlogRepository parentBlogRepository; 18:   19: public BlogRepositoryWithCaching(IBlogRepository parentBlogRepository, ICacheProvider<Blog> cacheProvider) 20: { 21: if (parentBlogRepository == null) 22: throw new ArgumentNullException("parentBlogRepository"); 23:   24: this.parentBlogRepository = parentBlogRepository; 25:   26: if (cacheProvider == null) 27: throw new ArgumentNullException("cacheProvider"); 28:   29: this.cacheProvider = cacheProvider; 30: } 31:   32: public Blog GetByName(string name) 33: { 34: string key = string.Format("CacheDiSample.DataAccess.GetByName.{0}", name); 35: // hard code 5 minute expiry! 36: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 37: return cacheProvider.Fetch(key, () => 38: { 39: return parentBlogRepository.GetByName(name); 40: }, 41: null, relativeCacheExpiry); 42: } 43:   44: public Blog GetById(int id) 45: { 46: string key = string.Format("CacheDiSample.DataAccess.GetById.{0}", id); 47:   48: // hard code 5 minute expiry! 49: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 50: return cacheProvider.Fetch(key, () => 51: { 52: return parentBlogRepository.GetById(id); 53: }, 54: null, relativeCacheExpiry); 55: } 56:   57: public IList<Blog> GetAll() 58: { 59: string key = string.Format("CacheDiSample.DataAccess.GetAll"); 60:   61: // hard code 5 minute expiry! 62: TimeSpan relativeCacheExpiry = new TimeSpan(0, 5, 0); 63: return cacheProvider.Fetch(key, () => 64: { 65: return parentBlogRepository.GetAll(); 66: }, 67: null, relativeCacheExpiry) 68: .ToList(); 69: } 70: } 71: }   The key things in this caching repository are: I inject into the repository the ICacheProvider<Blog> implementation, via the constructor. This will make the cache provider functionality available to the repository. I inject the parent IBlogRepository implementation (which has the actual data access code), via the constructor. This will allow the methods implemented in the parent to be called if nothing is found in the cache. I override each of the methods implemented in the repository, including those implemented in the generic BaseRepository. Each override of these methods follows the same pattern. It makes a call to the CacheProvider.Fetch method, and passes in the parentBlogRepository implementation of the method as the retrieval method, to be used if nothing is present in the cache. Configuring the Caching Repository in the DI Container The final piece of the jigsaw is to tell Castle Windsor to use the BlogRepositoryWithCaching implementation of IBlogRepository, but to inject the actual Data Access implementation into this decorator. This is easily achieved by modifying the RepositoriesInstaller to use Windsor’s implicit decorator wiring: 1: using Castle.MicroKernel.Registration; 2: using Castle.MicroKernel.SubSystems.Configuration; 3: using Castle.Windsor; 4:   5: using CacheDiSample.Domain.CacheDecorators; 6: using CacheDiSample.Domain.Repositories; 7: using CacheDiSample.DataAccess; 8:   9: namespace CacheDiSample.WindsorInstallers 10: { 11: public class RepositoriesInstaller : IWindsorInstaller 12: { 13: public void Install(IWindsorContainer container, IConfigurationStore store) 14: { 15:   16: // Use Castle Windsor implicit wiring for the block repository decorator 17: // Register the outermost decorator first 18: container.Register(Component.For<IBlogRepository>() 19: .ImplementedBy<BlogRepositoryWithCaching>() 20: .LifestyleTransient()); 21: // Next register the IBlogRepository inmplementation to inject into the outer decorator 22: container.Register(Component.For<IBlogRepository>() 23: .ImplementedBy<BlogRepository>() 24: .LifestyleTransient() 25: .DependsOn(new 26: { 27: nameOrConnectionString = "BloggingContext" 28: })); 29: } 30: } 31: }   This is all that is needed. Now if the consumer of the repository makes a call to the repositories method, it will be routed via the caching mechanism. You can test this by stepping through the code, and seeing that the DataAccess.BlogRepository code is only called if there is no data in the cache, or this has expired. The next step is to add the SQL Cache Dependency support into this pattern, this will be a future post.

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