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• Review: A Quick Look at Reflector

  - by James Michael Hare

  I, like many, was disappointed when I heard that Reflector 7 was not free, and perhaps that’s why I waited so long to try it and just kept using my version 6 (which continues to be free).  But though I resisted for so long, I longed for the better features that were being developed, and began to wonder if I should upgrade.  Thus, I began to look into the features being offered in Reflector 7.5 to see what was new. Multiple Editions Reflector 7.5 comes in three flavors, each building on the features of the previous version: Standard – Contains just the Standalone application ($70) VS – Same as Standard but adds Reflector Object Browser for Visual Studio ($130) VSPro – Same as VS but adds ability to set breakpoints and step into decompiled code ($190) So let’s examine each of these features. The Standalone Application (Standard, VS, VSPro editions) Popping open Reflector 7.5 and looking at the GUI, we see much of the same familiar features, with a few new ones as well: Most notably, the disassembler window now has a tabbed window with navigation buttons.  This makes it much easier to back out of a deep-dive into many layers of decompiled code back to a previous point. Also, there is now an analyzer which can be used to determine dependencies for a given method, property, type, etc. For example, if we select System.Net.Sockets.TcpClient and hit the Analyze button, we’d see a window with the following nodes we could expand: This gives us the ability to see what a given type uses, what uses it, who exposes it, and who instantiates it. Now obviously, for low-level types (like DateTime) this list would be enormous, but this can give a lot of information on how a given type is connected to the larger code ecosystem. One of the other things I like about using Reflector 7.5 is that it does a much better job of displaying iterator blocks than Reflector 6 did. For example, if you were to take a look at the Enumerable.Cast() extension method in System.Linq, and dive into the CastIterator in Reflector 6, you’d see this: But now, in Reflector 7.5, we see the iterator logic much more clearly: This is a big improvement in the quality of their code disassembler and for me was one of the main reasons I decided to take the plunge and get version 7.5. The Reflector Object Browser (VS, VSPro editions) If you have the .NET Reflector VS or VSPro editions, you’ll find you have in Visual Studio a Reflector Object Browser window available where you can select and decompile any assembly right in Visual Studio. For example, if you want to take a peek at how System.Collections.Generic.List<T> works, you can either select List<T> in the Reflector Object Browser, or even simpler just select a usage of it in your code and CTRL + Click to dive in. – And it takes you right to a source window with the decompiled source: Setting Breakpoints and Stepping Into Decompiled Code (VSPro) If you have the VSPro edition, in addition to all the things said above, you also get the additional ability to set breakpoints in this decompiled code and step through it as if it were your own code: This can be a handy feature when you need to see why your code’s use of a BCL or other third-party library isn’t working as you expect. Summary Yes, Reflector is no longer free, and yes, that’s a bit of a bummer. But it always was and still is a very fine tool. If you still have Reflector 6, you aren’t forced to upgrade any longer, but getting the nicer disassembler (especially for iterator blocks) and the handy VS integration is worth at least considering upgrading for.  So I leave it up to you, these are some of the features of Reflector 7.5, what’s your thoughts? Technorati Tags: .NET,Reflector

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• Bind a Wijmo Grid to Salesforce.com Through the Salesforce OData Connector

  - by dataintegration

  This article will explain how to connect to any RSSBus OData Connector with Wijmo's data grid using JSONP. While the example will use the Salesforce Connector, the same process can be followed for any of the RSSBus OData Connectors. Step 1: Download and install both the Salesforce Connector from RSSBus and the Wijmo javascript library. Step 2: Next you will want to configure the Salesforce Connector to connect with your Salesforce account. If you browse to the Help tab in the Salesforce Connector application, there is a link to the Getting Started Guide which will walk you through setting up the Salesforce Connector. Step 3: Once you have successfully configured the Salesforce Connector application, you will want to open a Wijmo sample grid file to edit. This example will use the overview.html grid found in the Samples folder. Step 4: First, we will wrap the jQuery document ready function in a callback function for the JSONP service. In this example, we will wrap this in function called fnCallback which will take a single object args. <script id="scriptInit" type="text/javascript"> function fnCallback(args) { $(document).ready(function () { $("#demo").wijgrid({ ... }); }); }; </script> Step 5: Next, we need to format the columns object in a format that Wijmo's data grid expects. This is done by adding the headerText: element for each column. <script id="scriptInit" type="text/javascript"> function fnCallback(args) { var columns = []; for (var i = 0; i < args.columnnames.length; i++){ var col = { headerText: args.columnnames[i]}; columns.push(col); } $(document).ready(function () { $("#demo").wijgrid({ ... }); }); }; </script> Step 6: Now the wijgrid parameters are ready to be set. In this example, we will set the data input parameter to the args.data object and the columns input parameter to our newly created columns object. The resulting javascript function should look like this: <script id="scriptInit" type="text/javascript"> function fnCallback(args) { var columns = []; for (var i = 0; i < args.columnnames.length; i++){ var col = { headerText: args.columnnames[i]}; columns.push(col); } $(document).ready(function () { $("#demo").wijgrid({ allowSorting: true, allowPaging: true, pageSize: 10, data: args.data, columns: columns }); }); }; </script> Step 7: Finally, we need to add the JSONP reference to our Salesforce Connector's data table. You can find this by clicking on the Settings tab of the Salesforce Connector. Once you have found the JSONP URL, you will need to supply a valid table name that you want to connect with Wijmo. In this example, we will connect to the Lead table. You will also need to add authentication options in this step. In the example we will append the authtoken of the user who has access to the Salesforce Connector using the @authtoken query string parameter. IMPORTANT: This is not secure and will expose the authtoken of the user whose authtoken you supply in this step. There are other ways to secure the user's authtoken, but this example uses a query string parameter for simplicity. <script src="http://localhost:8181/sfconnector/data/conn/Lead.rsd?@jsonp=fnCallback&sql:query=SELECT%20*%20FROM%20Lead&@authtoken=<myAuthToken>" type="text/javascript"></script> Step 8: Now, we are done. If you point your browser to the URL of the sample, you should see your Salesforce.com leads in a Wijmo data grid.

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• Having fun with Reflection

  - by Nick Harrison

  I was once asked in a technical interview what I could tell them about Reflection.   My response, while a little tongue in cheek was that "I can tell you it is one of my favorite topics to talk about" I did get a laugh out of that and it was a great ice breaker.    Reflection may not be the answer for everything, but it often can be, or maybe even should be.     I have posted in the past about my favorite CopyTo method.   It can come in several forms and is often very useful.   I explain it further and expand on the basic idea here  The basic idea is to allow reflection to loop through the properties of two objects and synchronize the ones that are in common.   I love this approach for data binding and passing data across the layers in an application. Recently I have been working on a project leveraging Data Transfer Objects to pass data through WCF calls.   We won't go into how the architecture got this way, but in essence there is a partial duplicate inheritance hierarchy where there is a related Domain Object for each Data Transfer Object.     The matching objects do not share a common ancestor or common interface but they will have the same properties in common.    By passing the problems with this approach, let's talk about how Reflection and our friendly CopyTo could make the most of this bad situation without having to change too much. One of the problems is keeping the two sets of objects in synch.   For this particular project, the DO has all of the functionality and the DTO is used to simply transfer data back and forth.    Both sets of object have parallel hierarchies with the same properties being defined at the corresponding levels.   So we end with BaseDO,  BaseDTO, GenericDO, GenericDTO, ProcessAreaDO,  ProcessAreaDTO, SpecializedProcessAreaDO, SpecializedProcessAreaDTO, TableDo, TableDto. and so on. Without using Reflection and a CopyTo function, tremendous care and effort must be made to keep the corresponding objects in synch.    New properties can be added at any level in the inheritance and must be kept in synch at all subsequent layers.    For this project we have come up with a clever approach of calling a base GetDo or UpdateDto making sure that the same method at each level of inheritance is called.    Each level is responsible for updating the properties at that level. This is a lot of work and not keeping it in synch can create all manner of problems some of which are very difficult to track down.    The other problem is the type of code that this methods tend to wind up with. You end up with code like this: Transferable dto = new Transferable(); base.GetDto(dto); dto.OfficeCode = GetDtoNullSafe(officeCode); dto.AccessIndicator = GetDtoNullSafe(accessIndicator); dto.CaseStatus = GetDtoNullSafe(caseStatus); dto.CaseStatusReason = GetDtoNullSafe(caseStatusReason); dto.LevelOfService = GetDtoNullSafe(levelOfService); dto.ReferralComments = referralComments; dto.Designation = GetDtoNullSafe(designation); dto.IsGoodCauseClaimed = GetDtoNullSafe(isGoodCauseClaimed); dto.GoodCauseClaimDate = goodCauseClaimDate;       One obvious problem is that this is tedious code.   It is error prone code.    Adding helper functions like GetDtoNullSafe help out immensely, but there is still an easier way. We can bypass the tedious code, by pass the complex inheritance tricks, and reduce all of this to a single method in the base class. TransferObject dto = new TransferObject(); CopyTo (this, dto); return dto; In the case of this one project, such a change eliminated the need for 20% of the total code base and a whole class of unit test cases that made sure that all of the properties were in synch. The impact of such a change also needs to include the on going time savings and the improvements in quality that can arise from them.    Developers who are not worried about keeping the properties in synch across mirrored object hierarchies are freed to worry about more important things like implementing business requirements.

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• Deploying Data Mining Models using Model Export and Import

  - by [email protected]

  In this post, we'll take a look at how Oracle Data Mining facilitates model deployment. After building and testing models, a next step is often putting your data mining model into a production system -- referred to as model deployment. The ability to move data mining model(s) easily into a production system can greatly speed model deployment, and reduce the overall cost. Since Oracle Data Mining provides models as first class database objects, models can be manipulated using familiar database techniques and technology. For example, one or more models can be exported to a flat file, similar to a database table dump file (.dmp). This file can be moved to a different instance of Oracle Database EE, and then imported. All methods for exporting and importing models are based on Oracle Data Pump technology and found in the DBMS_DATA_MINING package. Before performing the actual export or import, a directory object must be created. A directory object is a logical name in the database for a physical directory on the host computer. Read/write access to a directory object is necessary to access the host computer file system from within Oracle Database. For our example, we'll work in the DMUSER schema. First, DMUSER requires the privilege to create any directory. This is often granted through the sysdba account. grant create any directory to dmuser; Now, DMUSER can create the directory object specifying the path where the exported model file (.dmp) should be placed. In this case, on a linux machine, we have the directory /scratch/oracle. CREATE OR REPLACE DIRECTORY dmdir AS '/scratch/oracle'; If you aren't sure of the exact name of the model or models to export, you can find the list of models using the following query: select model_name from user_mining_models; There are several options when exporting models. We can export a single model, multiple models, or all models in a schema using the following procedure calls: BEGIN   DBMS_DATA_MINING.EXPORT_MODEL ('MY_MODEL.dmp','dmdir','name =''MY_DT_MODEL'''); END; BEGIN   DBMS_DATA_MINING.EXPORT_MODEL ('MY_MODELS.dmp','dmdir',              'name IN (''MY_DT_MODEL'',''MY_KM_MODEL'')'); END; BEGIN   DBMS_DATA_MINING.EXPORT_MODEL ('ALL_DMUSER_MODELS.dmp','dmdir'); END; A .dmp file can be imported into another schema or database using the following procedure call, for example: BEGIN   DBMS_DATA_MINING.IMPORT_MODEL('MY_MODELS.dmp', 'dmdir'); END; As with models from any data mining tool, when moving a model from one environment to another, care needs to be taken to ensure the transformations that prepare the data for model building are matched (with appropriate parameters and statistics) in the system where the model is deployed. Oracle Data Mining provides automatic data preparation (ADP) and embedded data preparation (EDP) to reduce, or possibly eliminate, the need to explicitly transport transformations with the model. In the case of ADP, ODM automatically prepares the data and includes the necessary transformations in the model itself. In the case of EDP, users can associate their own transformations with attributes of a model. These transformations are automatically applied when applying the model to data, i.e., scoring. Exporting and importing a model with ADP or EDP results in these transformations being immediately available with the model in the production system.

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• Asp.net Session State Revisited

  - by karan@dotnet

  Every now and then I see doubts and queries which I believe is the most discussed topic in the .net environment - Asp.net Sessions. So what really are they, why are they needed and what does browser and .net do with it. These and some of the other questions I hope to answer with this post. Because of the stateless nature of the HTTP protocol there is always a need of state management in a web application. There are many other ways to store data but I feel Session state is amongst the most powerful one. The ASP.NET session state is a technology that lets you store server-side, user-specific data. Our web applications can then use data to process request from the user for which the session state was instantiated. So when does a session is first created? When we start a asp.net application a non-expiring cookie is created and its called as ASP.NET_SessionId. Basically there are two methods for this depending upon how you configure this setting in your config file. The session ID can be a part of cookie as discussed above(called as ASP.NET_SessionId) or it is embedded in the browser’s URL. For the latter part we have to set cookie-less session in our web.config file. These Session ID’s are 120-bit random number that is represented by 20-character string. The cookie will be alive until you close your browser. If you browse from one app to another within the same domain, then both the apps will use the same session ID to track the session state. Why reuse? so that you don’t have to create a new session ID for each request. One can abandon one particular Session by calling Session.Abandon() which will stop the page processing and clear out the session data. A subsequent page request causes a brand new session object to be instantiated. So what happened to my cookie? Well the session cookie is still there even when one Session.Abandon() is called and another session object is created. The Session.Abandon() lets you clear out your session state without waiting for session timeout. By default, this time-out is a 20-minute sliding expiration. This expiration is refreshed every time that the user makes a request to the Web site and presents the session ID cookie. The Abandon method sets a flag in the session state object that indicates that the session state should be abandoned. If your app does not have global.asax then your session cookie will be killed at the end of each page request. So you need to have a global.asax file and Session_Start() handler to make sure that the session cookie will remain intact once its issued after the first page hit. The runtime invokes global.asax’s Session_OnEnd() when you call Session.Abandon() or the session times out. The session manager stores session data in HttpCache with sliding expiration where this timeout can be configured in the <sessionState> of web.config file. When the timeout is up the HttpCache will remove the session state object. Sometimes we want particular pages not to time out as compared to other pages in our applications. We can handle this in two ways. First, we can set a timer or may be a JavaScript function that refreshes the page after fixed intervals of time. The only thing being the page being cached locally and then the request is not made to the server so to prevent that you can add this to your page: <%@ OutputCache Location="None" VaryByParam="None" %> Second approach is to move your page into its own folder and then add a web.config to that folder to control the timeout. Also not all pages in your application will need access to session state. For those pages that do not, you can indicate that session state is not needed and prevent session data from being fetched from the store in requests to these pages. You can disable the session state at page level like this:<%@ Page EnableSessionState="False" %>tbc…

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• Implementing features in an Entity System

  - by Bane

  After asking two questions on Entity Systems (1, 2), and reading some articles on them, I think that I understand them much better than before. But, I still have some uncertainties, and mainly they are about building a Particle Emitter, an Input system, and a Camera. I obviously still have some problems understanding Entity Systems, and they might apply to a whole other range of objects, but I chose these three because they are very different concepts and should cover a pretty big ground, and help me understand Entity Systems and how to handle problems like these myself, as they come along. I am building an engine in Javascript, and I've implemented most of the core features, which include: input handling, flexible animation system, particle emitter, math classes and functions, scene handling, a camera and a render, and a whole bunch of other things that engines usually support. Then, I read Byte56's answer that got me interested into making the engine into an Entity System one. It would still remain an HTML5 game engine with the basic Scene philosophy, but it should support dynamic creation of entities from components. These are some of the definitions from the previous questions, updated: An Entity is an identifier. It doesn't have any data, it's not an object, it's a simple id that represents an index in the Scene's list of all entities (which I actually plan to implement as a component matrix). A Component is a data holder, but with methods that can operate on that data. The best example is a Vector2D, or a "Position" component. It has data: x and y, but also some methods that make operating on the data a bit easier: add(), normalize(), and so on. A System is something that can operate on a set of entities that meet the certain requirements, usually they (the entities) need to have a specified (by the system itself) set of components to be operated upon. The system is the "logic" part, the "algorithm" part, all the functionality supplied by components is purely for easier data management. The problem that I have now is fitting my old engine concept into this new programming paradigm. Lets start with the simplest one, a Camera. The camera has a position property (Vector2D), a rotation property and some methods for centering it around a point. Each frame, it is fed to a renderer, along with a scene, and all the objects are translated according to it's position. Then the scene is rendered. How could I represent this kind of an object in an Entity System? Would the camera be an entity or simply a component? A combination (see my answer)? Another issues that is bothering me is implementing a Particle Emitter. For what exactly I mean by that, you can check out my video of it: http://youtu.be/BObargIMQsE. The problem I have with this is, again, what should be what. I'm pretty sure that particles themselves shouldn't be entities, as I want to support 10k+ of them, and creating that much entities would be a heavy blow on my performance, I believe. Or maybe not? Depends on the implementation, but anyone with experience: please, do answer. The last bit I wan't to talk about, which is also bugging me the most, is how input should be handled. In my current version of the engine, there is a class called Input. It's a handler that subscribes to browser's events, such as keypresses, and mouse position changes, and also it maintains an internal state. Then, the player class has a react() method, which accepts an input object as an argument. The advantage of this is that the input object could be serialized into JSON and then shared over the network, allowing for smooth multiplayer simulations. But how does this translate into an Entity System?

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• Combining template method with strategy

  - by Mekswoll

  An assignment in my software engineering class is to design an application which can play different forms a particular game. The game in question is Mancala, some of these games are called Wari or Kalah. These games differ in some aspects but for my question it's only important to know that the games could differ in the following: The way in which the result of a move is handled The way in which the end of the game is determined The way in which the winner is determined The first thing that came to my mind to design this was to use the strategy pattern, I have a variation in algorithms (the actual rules of the game). The design could look like this: I then thought to myself that in the game of Mancala and Wari the way the winner is determined is exactly the same and the code would be duplicated. I don't think this is by definition a violation of the 'one rule, one place' or DRY principle seeing as a change in rules for Mancala wouldn't automatically mean that rule should be changed in Wari as well. Nevertheless from the feedback I got from my professor I got the impression to find a different design. I then came up with this: Each game (Mancala, Wari, Kalah, ...) would just have attribute of the type of each rule's interface, i.e. WinnerDeterminer and if there's a Mancala 2.0 version which is the same as Mancala 1.0 except for how the winner is determined it can just use the Mancala versions. I think the implementation of these rules as a strategy pattern is certainly valid. But the real problem comes when I want to design it further. In reading about the template method pattern I immediately thought it could be applied to this problem. The actions that are done when a user makes a move are always the same, and in the same order, namely: deposit stones in holes (this is the same for all games, so would be implemented in the template method itself) determine the result of the move determine if the game has finished because of the previous move if the game has finished, determine who has won Those three last steps are all in my strategy pattern described above. I'm having a lot of trouble combining these two. One possible solution I found would be to abandon the strategy pattern and do the following: I don't really see the design difference between the strategy pattern and this? But I am certain I need to use a template method (although I was just as sure about having to use a strategy pattern). I also can't determine who would be responsible for creating the TurnTemplate object, whereas with the strategy pattern I feel I have families of objects (the three rules) which I could easily create using an abstract factory pattern. I would then have a MancalaRuleFactory, WariRuleFactory, etc. and they would create the correct instances of the rules and hand me back a RuleSet object. Let's say that I use the strategy + abstract factory pattern and I have a RuleSet object which has algorithms for the three rules in it. The only way I feel I can still use the template method pattern with this is to pass this RuleSet object to my TurnTemplate. The 'problem' that then surfaces is that I would never need my concrete implementations of the TurnTemplate, these classes would become obsolete. In my protected methods in the TurnTemplate I could just call ruleSet.determineWinner(). As a consequence, the TurnTemplate class would no longer be abstract but would have to become concrete, is it then still a template method pattern? To summarize, am I thinking in the right way or am I missing something easy? If I'm on the right track, how do I combine a strategy pattern and a template method pattern? This is part of a homework assignment but I'm not looking to be gifted the answer, I have deliberately been very verbose in my question to show that I have thought about it before coming here to ask a question

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• Ubuntu 12.04 // Likewise Open // Unable to ever authenticate AD users

  - by Rob

  So Ubuntu 12.04, Likewise latest from the beyondtrust website. Joins domain fine. Gets proper information from lw-get-status. Can use lw-find-user-by-name to retrieve/locate users. Can use lw-enum-users to get all users. Attempting to login with an AD user via SSH generates the following errors in the auth.log file: Nov 28 19:15:45 hostname sshd[2745]: PAM unable to dlopen(pam_winbind.so): /lib/security/pam_winbind.so: cannot open shared object file: No such file or directory Nov 28 19:15:45 hostname sshd[2745]: PAM adding faulty module: pam_winbind.so Nov 28 19:15:51 hostname sshd[2745]: error: PAM: Authentication service cannot retrieve authentication info for DOMAIN\\user.name from remote.hostname Nov 28 19:16:06 hostname sshd[2745]: Connection closed by 10.1.1.84 [preauth] Attempting to login via the LightDM itself generates similar errors in the auth.log file. Nov 28 19:19:29 hostname lightdm: PAM unable to dlopen(pam_winbind.so): /lib/security/pam_winbind.so: cannot open shared object file: No such file or directory Nov 28 19:19:29 hostname lightdm: PAM adding faulty module: pam_winbind.so Nov 28 19:19:47 hostname lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "DOMAIN\user.name" Nov 28 19:19:52 hostname lightdm: [lsass-pam] [module:pam_lsass]pam_sm_authenticate error [login:DOMAIN\user.name][error code:40022] Nov 28 19:19:54 hostname lightdm: PAM unable to dlopen(pam_winbind.so): /lib/security/pam_winbind.so: cannot open shared object file: No such file or directory Nov 28 19:19:54 hostname lightdm: PAM adding faulty module: pam_winbind.so Attempting to login via a console on the system itself generates slightly different errors: Nov 28 19:31:09 hostname login[997]: PAM unable to dlopen(pam_winbind.so): /lib/security/pam_winbind.so: cannot open shared object file: No such file or directory Nov 28 19:31:09 hostname login[997]: PAM adding faulty module: pam_winbind.so Nov 28 19:31:11 hostname login[997]: [lsass-pam] [module:pam_lsass]pam_sm_authenticate error [login:DOMAIN\user.name][error code:40022] Nov 28 19:31:14 hostname login[997]: FAILED LOGIN (1) on '/dev/tty2' FOR 'DOMAIN\user.name', Authentication service cannot retrieve authentication info Nov 28 19:31:31 hostname login[997]: FAILED LOGIN (2) on '/dev/tty2' FOR 'DOMAIN\user.name', Authentication service cannot retrieve authentication info I am baffled. The errors obviously are correct, the file /lib/security/pam_winbind.so does not exist. If its a dependancy/required, surely it should be part of the package? I've installed/reinstalled, I've used the downloaded package from the beyondtrust website, i've used the repository, nothing seems to work, every method of installing this application generates the same errors for me. UPDATE : Hrmm, I thought likewise didn't use native winbind but its own modules. Installing winbind from apt-get uninstalls pbis-open (likewise) and generates failures when installing if pbis-open is installed first. Uninstalled winbind, reinstalled pbis-open, same issue as above. The file pam_winbind.so does not exist in that location. Setting up pbis-open-legacy (7.0.1.918) ... Installing Packages was successful This computer is joined to DOMAIN.LOCAL New libraries and configurations have been installed for PAM and NSS. Clearly it thinks it has installed it, but it hasn't. It may be a legacy issue with the previous attempt to configure domain integration manually with winbind. Does anyone have a working likewise-open installation and does the /etc/nsswitch.conf include references to winbind? Or do the /etc/pam.d/common-account or /etc/pam.d/common-password reference pam_winbind.so? I'm unsure if those entries are just legacy or setup by likewise. UPDATE 2 : Complete reinstall of OS fixed it and it worked seamlessly, like it was meant to and those 2 PAM files did NOT include entries for pam_winbind.so, so that was the underlying problem. Thanks for the assist.

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• Simple task framework - building software from reusable pieces

  - by RuslanD

  I'm writing a web service with several APIs, and they will be sharing some of the implementation code. In order not to copy-paste, I would like to ideally implement each API call as a series of tasks, which are executed in a sequence determined by the business logic. One obvious question is whether that's the best strategy for code reuse, or whether I can look at it in a different way. But assuming I want to go with tasks, several issues arise: What's a good task interface to use? How do I pass data computed in one task to another task in the sequence that might need it? In the past, I've worked with task interfaces like: interface Task<T, U> { U execute(T input); } Then I also had sort of a "task context" object which had getters and setters for any kind of data my tasks needed to produce or consume, and it gets passed to all tasks. I'm aware that this suffers from a host of problems. So I wanted to figure out a better way to implement it this time around. My current idea is to have a TaskContext object which is a type-safe heterogeneous container (as described in Effective Java). Each task can ask for an item from this container (task input), or add an item to the container (task output). That way, tasks don't need to know about each other directly, and I don't have to write a class with dozens of methods for each data item. There are, however, several drawbacks: Each item in this TaskContext container should be a complex type that wraps around the actual item data. If task A uses a String for some purpose, and task B uses a String for something entirely different, then just storing a mapping between String.class and some object doesn't work for both tasks. The other reason is that I can't use that kind of container for generic collections directly, so they need to be wrapped in another object. This means that, based on how many tasks I define, I would need to also define a number of classes for the task items that may be consumed or produced, which may lead to code bloat and duplication. For instance, if a task takes some Long value as input and produces another Long value as output, I would have to have two classes that simply wrap around a Long, which IMO can spiral out of control pretty quickly as the codebase evolves. I briefly looked at workflow engine libraries, but they kind of seem like a heavy hammer for this particular nail. How would you go about writing a simple task framework with the following requirements: Tasks should be as self-contained as possible, so they can be composed in different ways to create different workflows. That being said, some tasks may perform expensive computations that are prerequisites for other tasks. We want to have a way of storing the results of intermediate computations done by tasks so that other tasks can use those results for free. The task framework should be light, i.e. growing the code doesn't involve introducing many new types just to plug into the framework.

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• SharePoint 2010 Hosting :: Setting Default Column Values on a Folder Programmatically

  - by mbridge

  The reason I write this post today is because my initial searches on the Internet provided me with nothing on the topic.  I was hoping to find a reference to the SDK but I didn’t have any luck.  What I want to do is set a default column value on an existing folder so that new items in that folder automatically inherit that value.  It’s actually pretty easy to do once you know what the class is called in the API.  I did some digging and discovered that class is MetadataDefaults. It can be found in Microsoft.Office.DocumentManagement.dll.  Note: if you can’t find it in the GAC, this DLL is in the 14/CONFIG/BIN folder and not the 14/ISAPI folder.  Add a reference to this DLL in your project.  In my case, I am building a console application, but you might put this in an event receiver or workflow. In my example today, I have simple custom folder and document content types.  I have one shared site column called DocumentType.  I have a document library which each of these content types registered.  In my document library, I have a folder named Test and I want to set its default column values using code.  Here is what it looks like.  Start by getting a reference to the list in question.  This assumes you already have a SPWeb object.  In my case I have created it and it is called site. SPList customDocumentLibrary = site.Lists["CustomDocuments"]; You then pass the SPList object to the MetadataDefaults constructor. MetadataDefaults columnDefaults = new MetadataDefaults(customDocumentLibrary); Now I just need to get my SPFolder object in question and pass it to the meethod SetFieldDefault.  This takes a SPFolder object, a string with the name of the SPField to set the default on, and finally the value of the default (in my case “Memo”). SPFolder testFolder = customDocumentLibrary.RootFolder.SubFolders["Test"]; columnDefaults.SetFieldDefault(testFolder, "DocumentType", "Memo"); You can set multiple defaults here.  When you’re done, you will need to call .Update(). columnDefaults.Update(); Here is what it all looks like together. using (SPSite siteCollection = new SPSite("http://sp2010/sites/ECMSource")) {     using (SPWeb site = siteCollection.OpenWeb())     {         SPList customDocumentLibrary = site.Lists["CustomDocuments"];         MetadataDefaults columnDefaults = new MetadataDefaults(customDocumentLibrary);          SPFolder testFolder = customDocumentLibrary.RootFolder.SubFolders["Test"];         columnDefaults.SetFieldDefault(testFolder, "DocumentType", "Memo");         columnDefaults.Update();     } } You can verify that your property was set correctly on the Change Default Column Values page in your list This is something that I could see used a lot on an ItemEventReceiver attached to a folder to do metadata inheritance.  Whenever, the user changed the value of the folder’s property, you could have it update the default.  Your code might look something columnDefaults.SetFieldDefault(properties.ListItem.Folder, "MyField", properties.ListItem[" This is a great way to keep the child items updated any time the value a folder’s property changes.  I’m also wondering if this can be done via CAML.  I tried saving a site template, but after importing I got an error on the default values page.  I’ll keep looking and let you know what I find out.

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• Improvements to Joshua Bloch's Builder Design Pattern?

  - by Jason Fotinatos

  Back in 2007, I read an article about Joshua Blochs take on the "builder pattern" and how it could be modified to improve the overuse of constructors and setters, especially when an object has a large number of properties, most of which are optional. A brief summary of this design pattern is articled here [http://rwhansen.blogspot.com/2007/07/theres-builder-pattern-that-joshua.html]. I liked the idea, and have been using it since. The problem with it, while it is very clean and nice to use from the client perspective, implementing it can be a pain in the bum! There are so many different places in the object where a single property is reference, and thus creating the object, and adding a new property takes a lot of time. So...I had an idea. First, an example object in Joshua Bloch's style: Josh Bloch Style: public class OptionsJoshBlochStyle { private final String option1; private final int option2; // ...other options here <<<< public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private String option1; private int option2; // other options here <<<<< public Builder option1(String option1) { this.option1 = option1; return this; } public Builder option2(int option2) { this.option2 = option2; return this; } public OptionsJoshBlochStyle build() { return new OptionsJoshBlochStyle(this); } } private OptionsJoshBlochStyle(Builder builder) { this.option1 = builder.option1; this.option2 = builder.option2; // other options here <<<<<< } public static void main(String[] args) { OptionsJoshBlochStyle optionsVariation1 = new OptionsJoshBlochStyle.Builder().option1("firefox").option2(1).build(); OptionsJoshBlochStyle optionsVariation2 = new OptionsJoshBlochStyle.Builder().option1("chrome").option2(2).build(); } } Now my "improved" version: public class Options { // note that these are not final private String option1; private int option2; // ...other options here public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private final Options options = new Options(); public Builder option1(String option1) { this.options.option1 = option1; return this; } public Builder option2(int option2) { this.options.option2 = option2; return this; } public Options build() { return options; } } private Options() { } public static void main(String[] args) { Options optionsVariation1 = new Options.Builder().option1("firefox").option2(1).build(); Options optionsVariation2 = new Options.Builder().option1("chrome").option2(2).build(); } } As you can see in my "improved version", there are 2 less places in which we need to add code about any addition properties (or options, in this case)! The only negative that I can see is that the instance variables of the outer class are not able to be final. But, the class is still immutable without this. Is there really any downside to this improvement in maintainability? There has to be a reason which he repeated the properties within the nested class that I'm not seeing?

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• [EF + Oracle] Entities

  - by JTorrecilla

  Prologue Following with the Serie I started yesterday about Entity Framework with Oracle, Today I am going to start talking about Entities. What is an Entity? A Entity is an object of the EF model corresponding to a record in a DB table. For example, let’s see, in Image 1 we can see one Entity from our model, and in the second one we can see the mapping done with the DB. (Image 1) (Image 2) More in depth a Entity is a Class inherited from the abstract class “EntityObject”, contained by the “System.Data.Objects.DataClasses” namespace. At the same time, this class inherits from the following Class and interfaces: StructuralObject: It is an Abstract class that inherits from INotifyPropertyChanging and INotifyPropertyChanged interfaces, and it exposes the events that manage the Changes of the class, and the functions related to check the data types of the Properties from our Entity.  IEntityWithKey: Interface which exposes the Key of the entity. IEntityWithChangeTracker: Interface which lets indicate the state of the entity (Detached, Modified, Added…) IEntityWithRelationships: Interface which indicates the relations about the entity. Which is the Content of a Entity? A Entity is composed by: Properties, Navigation Properties and Methods. What is a Property? A Entity Property is an object that represents a column from the mapped table from DB. It has a data type equivalent in .Net Framework to the DB Type. When we create the EF model, VS, internally, create the code for each Entity selected in the Tables step, such all methods that we will see in next steps. For each property, VS creates a structure similar to: · Private variable with the mapped Data type. · Function with a name like On{Property_Name}Changing({dataType} value): It manages the event which happens when we try to change the value. · Function with a name like On{Property_Name}Change: It manages the event raised when the property has changed successfully. · Property with Get and Set methods: The Set Method manages the private variable and do the following steps: Raise Changing event. Report the Entity is Changing. Set the prívate variable. For it, Use the SetValidValue function of the StructuralObject. There is a function for each datatype, and the functions takes 2 params: the value, and if the prop allow nulls. Invoke that the entity has been successfully changed. Invoke the Changed event of the Prop. ReportPropertyChanging and ReportPropertyChanged events, let, respectively, indicate that there is pending changes in the Entity, and the changes have success correctly. While the ReportPropertyChanged is raised, the Track State of the Entity will be changed. What is a Navigation Property? Navigation Properties are a kind of property of the type: EntityCollection<TEntity>, where TEntity is an Entity type from the model related with the current one, it is said, is a set of record from a related table in the DB. The EntityCollection class inherits from: · RelatedEnd: There is an abstract class that give the functions needed to obtein the related objects. · ICollection<TEntity> · IEnumerable<TEntity> · IEnumerable · IListSource For the previous interfaces, I wish recommend the following post from Jose Miguel Torres. Navigation properties allow us, to get and query easily objects related with the Entity. Methods? There is only one method in the Entity object. “Create{Entity}”, that allow us to create an object of the Entity by sending the parameters needed to create it. Finally After this chapter, we know what is an Entity, how is related to the DB and the relation to other Entities. In following chapters, we will se CRUD operations(Create, Read, Update, Delete).

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• Threading Overview

  - by ACShorten

  One of the major features of the batch framework is the ability to support multi-threading. The multi-threading support allows a site to increase throughput on an individual batch job by splitting the total workload across multiple individual threads. This means each thread has fine level control over a segment of the total data volume at any time. The idea behind the threading is based upon the notion that "many hands make light work". Each thread takes a segment of data in parallel and operates on that smaller set. The object identifier allocation algorithm built into the product randomly assigns keys to help ensure an even distribution of the numbers of records across the threads and to minimize resource and lock contention. The best way to visualize the concept of threading is to use a "pie" analogy. Imagine the total workset for a batch job is a "pie". If you split that pie into equal sized segments, each segment would represent an individual thread. The concept of threading has advantages and disadvantages: Smaller elapsed runtimes - Jobs that are multi-threaded finish earlier than jobs that are single threaded. With smaller amounts of work to do, jobs with threading will finish earlier. Note: The elapsed runtime of the threads is rarely proportional to the number of threads executed. Even though contention is minimized, some contention does exist for resources which can adversely affect runtime. Threads can be managed individually – Each thread can be started individually and can also be restarted individually in case of failure. If you need to rerun thread X then that is the only thread that needs to be resubmitted. Threading can be somewhat dynamic – The number of threads that are run on any instance can be varied as the thread number and thread limit are parameters passed to the job at runtime. They can also be configured using the configuration files outlined in this document and the relevant manuals.Note: Threading is not dynamic after the job has been submitted Failure risk due to data issues with threading is reduced – As mentioned earlier individual threads can be restarted in case of failure. This limits the risk to the total job if there is a data issue with a particular thread or a group of threads. Number of threads is not infinite – As with any resource there is a theoretical limit. While the thread limit can be up to 1000 threads, the number of threads you can physically execute will be limited by the CPU and IO resources available to the job at execution time. Theoretically with the objects identifiers evenly spread across the threads the elapsed runtime for the threads should all be the same. In other words, when executing in multiple threads theoretically all the threads should finish at the same time. Whilst this is possible, it is also possible that individual threads may take longer than other threads for the following reasons: Workloads within the threads are not always the same - Whilst each thread is operating on the roughly the same amounts of objects, the amount of processing for each object is not always the same. For example, an account may have a more complex rate which requires more processing or a meter has a complex amount of configuration to process. If a thread has a higher proportion of objects with complex processing it will take longer than a thread with simple processing. The amount of processing is dependent on the configuration of the individual data for the job. Data may be skewed – Even though the object identifier generation algorithm attempts to spread the object identifiers across threads there are some jobs that use additional factors to select records for processing. If any of those factors exhibit any data skew then certain threads may finish later. For example, if more accounts are allocated to a particular part of a schedule then threads in that schedule may finish later than other threads executed. Threading is important to the success of individual jobs. For more guidelines and techniques for optimizing threading refer to Multi-Threading Guidelines in the Batch Best Practices for Oracle Utilities Application Framework based products (Doc Id: 836362.1) whitepaper available from My Oracle Support

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• Build-time dependency resolving coming to Entity Framework. Now, how about those BI tools too?

  - by jamiet

  Three months ago I wrote a blog post entitled Some thoughts on Visual Studio database references and how they should be used for SQL Server BI where I shared some thoughts on a feature available to database developers in Visual Studio 2010 that I would love to see added to SQL Server Integration Services (SSIS), Analysis Services (SSAS) and Reporting Services (SSRS). In there I said: Over the past few weeks I have been making heavy use of the Database tools in Visual Studio 2010 and one of the features that has most impressed me has been database references.   Database references allow you to have stored procedures in your database project that refer to objects (tables, views, stored procedures etc…) that exist in other database projects and hence when you build your database project it is able to resolve those references.   It occurred to me that similar functionality would be incredibly useful for SQL Server Integration Services(SSIS), Analysis Services (SSAS) & Reporting Services (SSRS) projects. After all reports, packages and data source views are rife with references to database objects – why shouldn’t we be able to have design-time dependency checking in our BI projects the same way that database and .Net developers do? In that blog post I shared links to three Connect submissions where I requested this feature be added to SSIS, SSAS & SSRS. In addition I also submitted a request that the feature be extended to .Net projects so that any reference to a database object in a .Net assembly can be resolved at build time. That Connect submission is at [Entity FX] Use database references to constrain the EDM and overnight it received this comment from Microsoft: We have been working on this feature for a while and and will be available soon This is really good news - it improves the Microsoft developer ecosystem by ensuring invalid references to database references get caught at build time (ideally as part of a Continuous integration build) rather than run time. [Hopefully it might nip this code-first nonsense in the bud too (Ooo...way to incite flame comments :) ) ]. If you want to see this feature in action then check out a video from Teched Europe last month entitled SQL Server Developer Tools Code-named "Juneau" where it is demo'd by Lance Delano and Tim Laverty.   The point of this blog post though is not just to draw attention to this forthcoming feature for .Net developers, it is to ask you to petition Microsoft to get this feature added to SSIS/SSAS/SSRS too. After all, we already know (from the video above) that the feature is coming to this new code-name Juneau development environment plus we also know that Juneau will be the development environment for SSIS/SSAS/SSRS as well - is it really much of a stretch to expect the BI tools to have access to this great feature too? I don't think so and if you agree with me then I urge you to vote and add a comment to the Connection submissions that are requesting this feature. They are at: [SSAS] Declare Object Dependancies [SSRS] Declare Object Dependancies [SSIS] Declare Object Dependancies (Update, Apparently someone at Microsoft has deemed it necassary to set this to private and I am not able to change it back even though I submitted it. You can still vote on the other two though.) Let's close that SQL Developer Gap!   @Jamiet    

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• Application Does Not Start in Windows 7

  - by Jim Fell

  I recently installed a new 60GB SSD as my primary hard drive and re-installed Windows 7 Professional 64-bit. I then installed SSD Fresh from Abelssoft to optimize Windows to run on the SSD. It seemed to install okay, but when I try to run the utility, its splash screen appears briefly before it quietly closes. No errors are displayed; the utility just fails to launch. I have run SSD Fresh on another SSD-equipped Windows 7 Pro x64 computer in the past without any problems. Does anyone know what might be preventing the program from running? I tried running sfc /scannow from the command line (with administrator privileges), shutting down the Spybot Resident, and disabling the firewall and virus scanner. I also tried running the tool as administrator; I even tried reinstalling it, running the installer as administrator. No luck. Every time I try to launch the program the Event Viewer logs this same set of errors: Error 4/2/2012 11:35:44 PM Application Error 1000 (100) Faulting application name: SSDFresh.exe, version: 1.0.0.0, time stamp: 0x4f2a45d8 Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000 Exception code: 0xc0000005 Fault offset: 0x000007ff0016dbba Faulting process id: 0x994 Faulting application start time: 0x01cd11fd9fe978df Faulting application path: C:\Program Files (x86)\SSD Fresh\SSDFresh.exe Faulting module path: unknown Report Id: dfeed551-7df0-11e1-a2c7-002522c47ec0 Error 4/2/2012 11:35:43 PM .NET Runtime 1026 None Application: SSDFresh.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.NullReferenceException Stack: at AbBugReporter.BugForm.InitLanguage() at AbBugReporter.BugForm..ctor(AbFlexTrans.LanguageInfo, AbBugReporter.BugReportManager, Boolean) at AbBugReporter.BugReportManager.Show(System.Exception) at SSDFresh.App.App_DispatcherUnhandledException(System.Object, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs) at System.Windows.Threading.Dispatcher.CatchException(System.Exception) at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(System.Object, System.Delegate, System.Object, Int32, System.Delegate) at System.Windows.Threading.Dispatcher.WrappedInvoke(System.Delegate, System.Object, Int32, System.Delegate) at System.Windows.Threading.Dispatcher.InvokeImpl(System.Windows.Threading.DispatcherPriority, System.TimeSpan, System.Delegate, System.Object, Int32) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr) at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef) at System.Windows.Threading.Dispatcher.PushFrameImpl(System.Windows.Threading.DispatcherFrame) at System.Windows.Application.RunInternal(System.Windows.Window) at System.Windows.Application.Run() at SSDFresh.App.Main() Error 4/2/2012 11:35:39 PM SideBySide 59 None Activation context generation failed for "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe".Error in manifest or policy file "C:\Windows\Microsoft.NET\Framework64\v4.0.30319\csc.exe.Config" on line 0. Invalid Xml syntax. Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None Error 4/2/2012 11:35:39 PM SideBySide 59 None For those who are interested, here is my system configuration: ASRock M3A770DE AM3 AMD 770 ATX AMD Motherboard AMD Athlon II X3 455 Rana 3.3GHz Socket AM3 95W Triple-Core Desktop Processor ADX455WFGMBOX G.SKILL Value Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10600) Desktop Memory Model F3-10600CL9D-8GBNT Mushkin Enhanced Chronos Deluxe MKNSSDCR60GB-DX 2.5" 60GB SATA III Synchronous MLC Internal Solid State Drive (SSD) (Primary/Boot HD) Western Digital Caviar Blue RFHWD1600AAJS 160GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive (Secondary HD) Sony Optiarc CD/DVD Burner Black SATA Model AD-7261S-0B LightScribe Support RAIDMAX RX-850AE 850W ATX12V v2.3 / EPS12V SLI Certified CrossFire Ready 80 PLUS GOLD Certified Modular Active PFC Power Supply ASUS HD7850-DC2-2GD5 Radeon HD 7850 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card Asus ML228H 21.5" Full HD LED BackLight LED Monitor Slim Design (x3)

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• Improving Click and Drag with C++

  - by Josh

  I'm currently using SFML 2.0 to develop a game in C++. I have a game sprite class that has a click and drag method. The method works, but there is a slight problem. If the mouse moves too fast, the object the user selected can't keep up and is left behind in the spot where the mouse left its bounds. I will share the class definition and the given function implementation. Definition: class codePeg { protected: FloatRect bounds; CircleShape circle; int xPos, yPos, xDiff, yDiff, once; int xBase, yBase; Vector2i mousePos; Vector2f circlePos; public: void init(RenderWindow& Window); void draw(RenderWindow& Window); void drag(RenderWindow& Window); void setPegPosition(int x, int y); void setPegColor(Color pegColor); void mouseOver(RenderWindow& Window); friend int isPegSelected(void); }; Implementation of the "drag" function: void codePeg::drag(RenderWindow& Window) { mousePos = Mouse::getPosition(Window); circlePos = circle.getPosition(); if(Mouse::isButtonPressed(Mouse::Left)) { if(mousePos.x > xPos && mousePos.y > yPos && mousePos.x - bounds.width < xPos && mousePos.y - bounds.height < yPos) { if(once) { xDiff = mousePos.x - circlePos.x; yDiff = mousePos.y - circlePos.y; once = 0; } xPos = mousePos.x - xDiff; yPos = mousePos.y - yDiff; circle.setPosition(xPos, yPos); } } else { once = 1; xPos = xBase; yPos = yBase; xDiff = 0; yDiff = 0; circle.setPosition(xBase, yBase); } Window.draw(circle); } Like I said, the function works, but to me, the code is very ugly and I think it could be improved and could be more efficient. The only thing I can think of as to why the object cannot keep up with the mouse is that there are too many function calls and/or checks. The user does not really have to mouse the mouse "fast" for it to happen, I would say at an average pace the object is left behind. How can I improve the code so that the object remains with the mouse when it is selected? Any help improving this code or giving advice is greatly appreciated.

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• how to use ajax with json in ruby on rails

  - by rafik860

  I am implemeting a facebook application in rails using facebooker plugin, therefore it is very important to use this architecture if i want to update multiple DOM in my page. if my code works in a regular rails application it would work in my facebook application. i am trying to use ajax to let the user know that the comment was sent, and update the comments bloc. migration: class CreateComments < ActiveRecord::Migration def self.up create_table :comments do |t| t.string :body t.timestamps end end def self.down drop_table :comments end end controller: class CommentsController < ApplicationController def index @comments=Comment.all end def create @comment=Comment.create(params[:comment]) if request.xhr? @comments=Comment.all render :json=>{:ids_to_update=>[:all_comments,:form_message], :all_comments=>render_to_string(:partial=>"comments" ), :form_message=>"Your comment has been added." } else redirect_to comments_url end end end view: <script> function update_count(str,message_id) { len=str.length; if (len < 200) { $(message_id).innerHTML="<span style='color: green'>"+ (200-len)+" remaining</span>"; } else { $(message_id).innerHTML="<span style='color: red'>"+ "Comment too long. Only 200 characters allowed.</span>"; } } function update_multiple(json) { for( var i=0; i<json["ids_to_update"].length; i++ ) { id=json["ids_to_update"][i]; $(id).innerHTML=json[id]; } } </script> <div id="all_comments" > <%= render :partial=>"comments/comments" %> </div> Talk some trash: <br /> <% remote_form_for Comment.new, :url=>comments_url, :success=>"update_multiple(request)" do |f|%> <%= f.text_area :body, :onchange=>"update_count(this.getValue(),'remaining');" , :onkeyup=>"update_count(this.getValue(),'remaining');" %> <br /> <%= f.submit 'Post'%> <% end %> <p id="remaining" >&nbsp;</p> <p id="form_message" >&nbsp;</p> <br><br> <br> if i try to do alert(json) in the first line of the update_multiple function , i got an [object Object]. if i try to do alert(json["ids_to_update"][0]) in the first line of the update_multiple function , there is no dialog box displayed. however the comment got saved but nothing is updated. it seems like the object sent by rails is nil or cant be parsed by JSON.parse(json). questions: 1.how can javascript and rails know that i am dealing with json objects?deos ROR sent it a object format or a text format?how can it check that the json object has been sent 2.how can i see what is the returned json?do i have to parse it?how? 2.how can i debug this problem? 3.how can i get it to work?

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• How to define template directives (from an API perspective)?

  - by Ralph

  Preface I'm writing a template language (don't bother trying to talk me out of it), and in it, there are two kinds of user-extensible nodes. TemplateTags and TemplateDirectives. A TemplateTag closely relates to an HTML tag -- it might look something like div(class="green") { "content" } And it'll be rendered as <div class="green">content</div> i.e., it takes a bunch of attributes, plus some content, and spits out some HTML. TemplateDirectives are a little more complicated. They can be things like for loops, ifs, includes, and other such things. They look a lot like a TemplateTag, but they need to be processed differently. For example, @for($i in $items) { div(class="green") { $i } } Would loop over $items and output the content with the variable $i substituted in each time. So.... I'm trying to decide on a way to define these directives now. Template Tags The TemplateTags are pretty easy to write. They look something like this: [TemplateTag] static string div(string content = null, object attrs = null) { return HtmlTag("div", content, attrs); } Where content gets the stuff between the curly braces (pre-rendered if there are variables in it and such), and attrs is either a Dictionary<string,object> of attributes, or an anonymous type used like a dictionary. It just returns the HTML which gets plunked into its place. Simple! You can write tags in basically 1 line. Template Directives The way I've defined them now looks like this: [TemplateDirective] static string @for(string @params, string content) { var tokens = Regex.Split(@params, @"\sin\s").Select(s => s.Trim()).ToArray(); string itemName = tokens[0].Substring(1); string enumName = tokens[1].Substring(1); var enumerable = data[enumName] as IEnumerable; var sb = new StringBuilder(); var template = new Template(content); foreach (var item in enumerable) { var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; sb.Append(template.Render(templateVars)); } return sb.ToString(); } (Working example). Basically, the stuff between the ( and ) is not split into arguments automatically (like the template tags do), and the content isn't pre-rendered either. The reason it isn't pre-rendered is because you might want to add or remove some template variables or something first. In this case, we add the $i variable to the template variables, var templateVars = new Dictionary<string, object>(data) { { itemName, item } }; And then render the content manually, sb.Append(template.Render(templateVars)); Question I'm wondering if this is the best approach to defining custom Template Directives. I want to make it as easy as possible. What if the user doesn't know how to render templates, or doesn't know that he's supposed to? Maybe I should pass in a Template instance pre-filled with the content instead? Or maybe only let him tamper w/ the template variables, and then automatically render the content at the end? OTOH, for things like "if" if the condition fails, then the template wouldn't need to be rendered at all. So there's a lot of flexibility I need to allow in here. Thoughts?

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• Getting the number of fragments which passed the depth test

  - by Etan

  In "modern" environments, the "NV Occlusion Query" extension provides a method to get the number of fragments which passed the depth test. However, on the iPad / iPhone using OpenGL ES, the extension is not available. What is the most performant approach to implement a similar behaviour in the fragment shader? Some of my ideas: Render the object completely in white, then count all the colors together using a two-pass shader where first a vertical line is rendered and for each fragment the shader computes the sum over the whole row. Then, a single vertex is rendered whose fragment sums all the partial sums of the first pass. Doesn't seem to be very efficient. Render the object completely in white over a black background. Downsample recursively, abusing the hardware linear interpolation between textures until being at a reasonably small resolution. This leads to fragments which have a greyscale level depending on the number of white pixels where in their corresponding region. Is this even accurate enough? Use mipmaps and simply read the pixel on the 1x1 level. Again the question of accuracy and if it is even possible using non-power-of-two textures. The problem wit these approaches is, that the pipeline gets stalled which results in major performance issues. Therefore, I'm looking for a more performant way to accomplish my goal. Using the EXT_OCCLUSION_QUERY_BOOLEAN extension Apple introduced EXT_OCCLUSION_QUERY_BOOLEAN in iOS 5.0 for iPad 2. "4.1.6 Occlusion Queries Occlusion queries use query objects to track the number of fragments or samples that pass the depth test. An occlusion query can be started and finished by calling BeginQueryEXT and EndQueryEXT, respectively, with a target of ANY_SAMPLES_PASSED_EXT or ANY_SAMPLES_PASSED_CONSERVATIVE_EXT. When an occlusion query is started with the target ANY_SAMPLES_PASSED_EXT, the samples-boolean state maintained by the GL is set to FALSE. While that occlusion query is active, the samples-boolean state is set to TRUE if any fragment or sample passes the depth test. When the occlusion query finishes, the samples-boolean state of FALSE or TRUE is written to the corresponding query object as the query result value, and the query result for that object is marked as available. If the target of the query is ANY_SAMPLES_PASSED_CONSERVATIVE_EXT, an implementation may choose to use a less precise version of the test which can additionally set the samples-boolean state to TRUE in some other implementation dependent cases." The first sentence hints on a behavior which is exactly what I'm looking for: getting the number of pixels which passed the depth test in an asynchronous manner without much performance loss. However, the rest of the document describes only how to get boolean results. Is it possible to exploit this extension to get the pixel count? Does the hardware support it so that there may be hidden API to get access to the pixel count? Other extensions which could be exploitable would be debugging features like the number of times the fragment shader was invoked (PSInvocations in DirectX - not sure if something simila is available in OpenGL ES). However, this would also result in a pipeline stall.

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• Library order is important

  - by Darryl Gove

  I've written quite extensively about link ordering issues, but I've not discussed the interaction between archive libraries and shared libraries. So let's take a simple program that calls a maths library function: #include <math.h int main() { for (int i=0; i<10000000; i++) { sin(i); } } We compile and run it to get the following performance: bash-3.2$ cc -g -O fp.c -lm bash-3.2$ timex ./a.out real 6.06 user 6.04 sys 0.01 Now most people will have heard of the optimised maths library which is added by the flag -xlibmopt. This contains optimised versions of key mathematical functions, in this instance, using the library doubles performance: bash-3.2$ cc -g -O -xlibmopt fp.c -lm bash-3.2$ timex ./a.out real 2.70 user 2.69 sys 0.00 The optimised maths library is provided as an archive library (libmopt.a), and the driver adds it to the link line just before the maths library - this causes the linker to pick the definitions provided by the static library in preference to those provided by libm. We can see the processing by asking the compiler to print out the link line: bash-3.2$ cc -### -g -O -xlibmopt fp.c -lm /usr/ccs/bin/ld ... fp.o -lmopt -lm -o a.out... The flag to the linker is -lmopt, and this is placed before the -lm flag. So what happens when the -lm flag is in the wrong place on the command line: bash-3.2$ cc -g -O -xlibmopt -lm fp.c bash-3.2$ timex ./a.out real 6.02 user 6.01 sys 0.01 If the -lm flag is before the source file (or object file for that matter), we get the slower performance from the system maths library. Why's that? If we look at the link line we can see the following ordering: /usr/ccs/bin/ld ... -lmopt -lm fp.o -o a.out So the optimised maths library is still placed before the system maths library, but the object file is placed afterwards. This would be ok if the optimised maths library were a shared library, but it is not - instead it's an archive library, and archive library processing is different - as described in the linker and library guide: "The link-editor searches an archive only to resolve undefined or tentative external references that have previously been encountered." An archive library can only be used resolve symbols that are outstanding at that point in the link processing. When fp.o is placed before the libmopt.a archive library, then the linker has an unresolved symbol defined in fp.o, and it will search the archive library to resolve that symbol. If the archive library is placed before fp.o then there are no unresolved symbols at that point, and so the linker doesn't need to use the archive library. This is why libmopt needs to be placed after the object files on the link line. On the other hand if the linker has observed any shared libraries, then at any point these are checked for any unresolved symbols. The consequence of this is that once the linker "sees" libm it will resolve any symbols it can to that library, and it will not check the archive library to resolve them. This is why libmopt needs to be placed before libm on the link line. This leads to the following order for placing files on the link line: Object files Archive libraries Shared libraries If you use this order, then things will consistently get resolved to the archive libraries rather than to the shared libaries.

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• [EF + ORACLE] Updating and Deleting Entities

  - by JTorrecilla

  Prologue In previous chapters we have seen how to insert data through EF, with and without sequences. In this one, we are going to see how to Update and delete Data from the DB. Updating data The update of the Entity Data (properties) is a very common and easy action. Before of change any of the properties of the Entity, we can check the EntityState property, and we can see that is EntityState.Unchanged.   For making an update it is needed to get the Entity which will be modified. In the following example, I use the GetEmployeeByNumber to get a valid Entity: 1: EMPLEADOS emp=GetEmployeeByNumber(2); 2: emp.Name="a"; 3: emp.Phone="2"; 4: emp.Mail="aa"; After modifying the desired properties of the Entity, we are going to check again Entitystate property, which now has the EntityState.Modified value. To persist the changes to the DB is necessary to invoke the SaveChanges function of our context. 1: context.SaveChanges(); After modifying the desired properties of the Entity, we are going to check again Entitystate property, which now has the EntityState.Modified value. To persist the changes to the DB is necessary to invoke the SaveChanges function of our context. If we check again the EntityState property we will see that the value will be EntityState.Unchanged.   Deleting Data Another easy action is to delete an Entity.   The first step to delete an Entity from the DB is to select the entity: 1: CLIENTS selectedClient = GetClientByNumber(15); 2: context.CLIENTES.DeleteObject(clienteSeleccionado); Before invoking the DeleteObject function, we will check EntityStet which value must be EntityState.Unchanged. After deleting the object, the state will be changed to EntitySate.Deleted. To commit the action we have to invoke the SaveChanges function. Aftar that, the EntityState property will be EntityState.Detached. Cascade Entity Framework lets cascade updates and deletes, although I never see cascade updates. What is a cascade delete? A cascade delete is an action that allows to delete all the related object to the object we desire to delete. This option could be established in the DB manager, or it could be in the EF model designer. For example: With a given relation (1-N) between clients and requests. The common situation must be to let delete those clients whose have no requests. If we select the relation between both entities, and press the second mouse button, we can see the properties panel of the relation. The props are: This grid shows the relations indicating the Master table(Clients) and the end point (Cabecera or Requests) The property “End 1 OnDelete” indicates the action to do when a Entity from the Master will be deleted. There are two options: - None: No action will be done, it is said, if a Entity has details entities it could not be deleted. - Cascade: It will delete all related entities to the master Entity. If we enable the cascade delete in a relation, and we invoke the DeleteObject function of the set, we could observe that all the related object indicates a Entitystate.Deleted state. Like an update, insert or common delete, until we commit the changes with SaveChanges function, the data would not be commited. Si habilitamos el borrado en cascada de una relación, e invocamos a la función DeleteObject del conjunto, podremos observar que todas las entidades de Detalle (de la relación indicada) presentan el valor EntityState.Deleted en la propiedad EntityState. Del mismo modo que en el borrado, inserción o actualización, hasta que no se invoque al método SaveChanges, los cambios no van a ser confirmados en la Base de Datos. Finally In this chapter we have seen how to update a Entity, how to delete an Entity and how to implement Cascade Deleting through EF. In next chapters we will see how to query the DB data.

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• WF4 &ndash; Guess the number game!

  - by MarkPearl

  I posted yesterday how really good WF4 was looking. Today I thought I would show some real basics that I was able to figure out. This will be a simple example, I am going to make a flowchart workflow – which will prompt the user to guess the number until they guess the right number. Lets begin… Make a new project and make it a Workflow console Application. Then select the Workflow file and drag a FlowChart (2) to point 3. This will now show a green start circle in the designer form. We are going to work with primitives to start with. We are now going to drag a few objects onto the Workflow, We drag the WriteLine, Assign & Decision items onto the designer. Once they are dragged onto the designer we will want to link them up. The order that they are linked is critical since this will determine the order of the solution. In this case, we want the system to first ask “Guess a number”, then to wait for the user to input some code, and then to display “You got it” if they got it right, and “Try again” if they got it wrong. So we now link the arrows to the objects. This is done by moving the mouse pointer over the start objects and clicking on one of the toggles and then dragging it to the next object and releasing the button over one of the toggles. This will place an arrow from the source object to the target object. Okay… pretty simple stuff – now we just need these primitive objects to do stuff. Lets start with the WriteLine primitive. We place the text in inverted commas in the Text field. Because this field accepts any valid VB expression we could have put variables etc. in there if we wanted to. The next thing we want to do is allow the user to input a number. This brings up an interesting problem, if a user were to type in a number, there would need to be someway to declare a variable to hold that value for the life of the workflow. We can achieve this by declaring a variable. To declare a variable, move your cursor over the variables tab at the bottom of the workflow, and then type the name of the new variable in the “Create Variable” field and set it as shown in the image above. Now that we have a variable, we want to call the Console.Readline method and assign the inputted value from the Console to that variable. The code that cannot be seen is actually this – Convert.ToInt32(Console.ReadLine()) We now have a workflow that first prompts the user for a number, then allows the user to type in a number. We are almost done, we just need to make the system react to the value inputted. There are a few ways we could do this, I am going to use the Decision item. So select the Decision object on the designer and then view its properties (F4 for me), and in the condition field place a condition. For simplicity sake I have decided that if the user guesses 10, they will have guessed the number. This is now the completed workflow. Its really easy to understand and shows some really powerful principles for Business applications. You can run the application and see what it does. Imagine writing business solutions that do not worry about the exact flow of objects, but simply allows a business analyst or someone to configure the solution to work exactly as the business rules would dictate. And if the rules changed six months later all they would need to do is re-drag some of the flows. Now I do not know if WF4 will allow for this, but it feels like it is a step in the right direct.

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• Lots of first chance Microsoft.CSharp.RuntimeBinderExceptions thrown when dealing with dynamics

  - by Orion Edwards

  I've got a standard 'dynamic dictionary' type class in C# - class Bucket : DynamicObject { readonly Dictionary<string, object> m_dict = new Dictionary<string, object>(); public override bool TrySetMember(SetMemberBinder binder, object value) { m_dict[binder.Name] = value; return true; } public override bool TryGetMember(GetMemberBinder binder, out object result) { return m_dict.TryGetValue(binder.Name, out result); } } Now I call it, as follows: static void Main(string[] args) { dynamic d = new Bucket(); d.Name = "Orion"; // 2 RuntimeBinderExceptions Console.WriteLine(d.Name); // 2 RuntimeBinderExceptions } The app does what you'd expect it to, but the debug output looks like this: A first chance exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in Microsoft.CSharp.dll A first chance exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in Microsoft.CSharp.dll 'ScratchConsoleApplication.vshost.exe' (Managed (v4.0.30319)): Loaded 'Anonymously Hosted DynamicMethods Assembly' A first chance exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in Microsoft.CSharp.dll A first chance exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in Microsoft.CSharp.dll Any attempt to access a dynamic member seems to output a RuntimeBinderException to the debug logs. While I'm aware that first-chance exceptions are not a problem in and of themselves, this does cause some problems for me: I often have the debugger set to "break on exceptions", as I'm writing WPF apps, and otherwise all exceptions end up getting converted to a DispatcherUnhandledException, and all the actual information you want is lost. WPF sucks like that. As soon as I hit any code that's using dynamic, the debug output log becomes fairly useless. All the useful trace lines that I care about get hidden amongst all the useless RuntimeBinderExceptions Is there any way I can turn this off, or is the RuntimeBinder unfortunately just built like that? Thanks, Orion

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• Silverlight - Adding Text to Pushpin in Bing Maps via C#

  - by Morano88

  I was able to make my silverlight Bing map accepts Mousclicks and converts them to Pushpins in C#. Now I want to show a text next to the PushPin as a description that appears when the mouse goes over the pin , I have no clue how to do that. What are the methods that enable me to do this thing? This is the C# code : public partial class MainPage : UserControl { private MapLayer m_PushpinLayer; public MainPage() { InitializeComponent(); base.Loaded += OnLoaded; } private void OnLoaded(object sender, RoutedEventArgs e) { base.Loaded -= OnLoaded; m_PushpinLayer = new MapLayer(); x_Map.Children.Add(m_PushpinLayer); x_Map.MouseClick += OnMouseClick; } private void AddPushpin(double latitude, double longitude) { Pushpin pushpin = new Pushpin(); pushpin.MouseEnter += OnMouseEnter; pushpin.MouseLeave += OnMouseLeave; m_PushpinLayer.AddChild(pushpin, new Location(latitude, longitude), PositionOrigin.BottomCenter); } private void OnMouseClick(object sender, MapMouseEventArgs e) { Point clickLocation = e.ViewportPoint; Location location = x_Map.ViewportPointToLocation(clickLocation); AddPushpin(location.Latitude, location.Longitude); } private void OnMouseLeave(object sender, MouseEventArgs e) { Pushpin pushpin = sender as Pushpin; // remove the pushpin transform when mouse leaves pushpin.RenderTransform = null; } private void OnMouseEnter(object sender, MouseEventArgs e) { Pushpin pushpin = sender as Pushpin; // scaling will shrink (less than 1) or enlarge (greater than 1) source element ScaleTransform st = new ScaleTransform(); st.ScaleX = 1.4; st.ScaleY = 1.4; // set center of scaling to center of pushpin st.CenterX = (pushpin as FrameworkElement).Height / 2; st.CenterY = (pushpin as FrameworkElement).Height / 2; pushpin.RenderTransform = st; } }

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• Displaying wait cursor in while backgroundworker is running

  - by arc1880

  During the start of my windows application, I have to make a call to a web service to retrieve some default data to load onto my application. During the load of the form, I run a backgroundworker to retrieve this data. I want to display the wait cursor until this data is retrieved. How would I do this? I've tried setting the wait cursor before calling the backgroundworker to run. When I report a progress of 100 then I set it back to the default cursor. The wait cursor comes up but when I move the mouse it disappears. Environment: Windows 7 Pro 64-bit VS2010 C# .NET 4.0 Windows Forms EDIT: I am setting the cursor the way Jay Riggs suggested. It only works if I don't move the mouse. **UPDATE: I have created a button click which does the following: When I do the button click and move my mouse, the wait cursor appears regardless if I move my mouse or not. void BtnClick() { Cursor = Cursors.WaitCursor; Thread.Sleep(8000); Cursor = Cursors.Default; } If I do the following: I see the wait cursor and when I move the mouse it disappears inside the form. If I move to my status bar or the menu bar the wait cursor appears. Cursor = Cursors.WaitCursor; if (!backgroundWorker.IsBusy) { backGroundWorker.RunWorkerAsync(); } void backGroundWorkerDoWork(object sender, DoWorkEventArgs e) { Thread.Sleep(8000); } void backGroundWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { Cursor = Cursors.Default; } If I do the following: The wait cursor appears and when I move the mouse it still appears but will sometimes flicker off and on when moving in text fields. if (!backgroundWorker.IsBusy) { backGroundWorker.RunWorkerAsync(); } void backGroundWorkerDoWork(object sender, DoWorkEventArgs e) { UseWaitCursor = true; Thread.Sleep(8000); } void backGroundWorkerCompleted(object sender, RunWorkerCompletedEventArgs e) { UseWaitCursor = false; }

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