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  • How to amend return value design in OO manner?

    - by FrontierPsycho
    Hello. I am no newb on OO programming, but I am faced with a puzzling situation. I have been given a program to work on and extend, but the previous developers didn't seem that comfortable with OO, it seems they either had a C background or an unclear understanding of OO. Now, I don't suggest I am a better developer, I just think that I can spot some common OO errors. The difficult task is how to amend them. In my case, I see a lot of this: if (ret == 1) { out.print("yadda yadda"); } else if (ret == 2) { out.print("yadda yadda"); } else if (ret == 3) { out.print("yadda yadda"); } else if (ret == 0) { out.print("yadda yadda"); } else if (ret == 5) { out.print("yadda yadda"); } else if (ret == 6) { out.print("yadda yadda"); } else if (ret == 7) { out.print("yadda yadda"); } ret is a value returned by a function, in which all Exceptions are swallowed, and in the catch blocks, the above values are returned explicitly. Oftentimes, the Exceptions are simply swallowed, with empty catch blocks. It's obvious that swalllowing exceptions is wrong OO design. My question concerns the use of return values. I believe that too is wrong, however I think that using Exceptions for control flow is equally wrong, and I can't think of anything to replace the above in a correct, OO manner. Your input, please?

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  • Sharing rails fragments between formats

    - by Julian
    Hi I'm toying with mobile_fu and want to share some fragments between the different views. E.g. views/ item/ view.html.erb view.mobile.rb shared/ _common.erb In both view.html.erb and view.mobile.erb I want to share the same fragment '_common.erb' without having to specify the format (should you ever have to specify the format inside a fragment? It doesn't seem like The Rails Way?). Let's say for arguments's sake it's because it's in a helper or whatever -- the point is that I need to share fragments in a 'well-defined and Railsy way' across formats. Let's take this fairly innocuous snippet <% render :fragment => 'shared/common' %> I've tried 3 file name conventions: _common.html.erb only works for html /item/view/xx fails with 'shared/_common.erb not found') however _common.erb fails for html and works for mobile (maybe mobile_fu is doing something wacky?) -- same error as for .html.erb version above _common.rhtml does work for both I'm thinking that: that rhtml works for both is a legacy hack and I'm loathe to rename all the shared fragments .rhtml to get the behaviour I want. Any feedback gratefully welcome! Including 'you fundamentally don't understand how Rails works please RTFM here: http://....' :)

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  • Fill listview from fragment

    - by Bohsen
    I have a layout file containing a listview that I would like to fill with the help of a Fragment. But it continues to give me errors. The layout file: <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <ListView android:id="@+id/list" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" > </ListView> <TableLayout android:id="@+id/details" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:stretchColumns="1" > <Button android:id="@+id/create_patient_button" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/create_patient_button" /> </TableLayout> </RelativeLayout> My fragmentActivity: public class BasicFragmentActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.create_patient_view); FragmentManager fm = getSupportFragmentManager(); Fragment fragment = fm.findFragmentById(R.id.list); if (fragment == null) { FragmentTransaction ft = fm.beginTransaction(); ft.add(R.id.list, new BasicFragment()); ft.commit(); // Make sure you call commit or your Fragment will not be added. // This is very common mistake when working with Fragments! } } } My ListFragment: public class BasicFragment extends ListFragment { private PatientAdapter pAdapter; @Override public void onActivityCreated(Bundle savedState) { super.onActivityCreated(savedState); pAdapter = new PatientAdapter(getActivity(), GFRApplication.dPatients); setListAdapter(pAdapter); } } The error: java.lang.UnsupportedOperationException: addView(View) is not supported in AdapterView

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  • Localisable Resources: how can (should one?!) wrap a UI layer source as a BL layer service?

    - by Ciel
    A service that returns localised strings could be wrapped in a service, so that it could be used both locally (eg in an MVC app) and remotely (eg possibly Silverlight). But...if sticking with the standard practice of creating resources in the UI assembly, that would in effect make a lower layer (BL/Services) have to have a ref on a higher layer (UI)...a definite no-no. And whereas a lot of AppWide resources (eg: AppName, OK, Cancel, etc.) could be defined in a Common cross-cutting assembly, and the BL/ResourceSerouce could ref and wrap those, that doesn't work in a a Modular App, where the Core app should have no binding to/knowledge of any Module. One solution could be to have each module, once mounted in mem, 'register' their Resource files with the service, who would then return it to the service (rather a long round trip, but at least consistent as a service, and potentially resources/images could be shared with other resources). Secondly, that may work in a web app...but not sure how that pattern could be extended to a Silverlight modular app (the round tripping becomes prohibitive). ie...what are best practices for allowing Resources to be to be defined by the UI designer, in a higher level, but served from the lower BL layer, as a Service? Or is there a better way of understanding/solving the problem?

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  • Is there a design pattern to cut down on code duplication when subclassing Activities in Android?

    - by Daniel Lew
    I've got a common task that I do with some Activities - downloading data then displaying it. I've got the downloading part down pat; it is, of course, a little tricky due to the possibility of the user changing the orientation or cancelling the Activity before the download is complete, but the code is there. There is enough code handling these cases such that I don't want to have to copy/paste it to each Activity I have, so I thought to create an abstract subclass Activity itself such that it handles a single background download which then launches a method which fills the page with data. This all works. The issue is that, due to single inheritance, I am forced to recreate the exact same class for any other type of Activity - for example, I use Activity, ListActivity and MapActivity. To use the same technique for all three requires three duplicate classes, except each extends a different Activity. Is there a design pattern that can cut down on the code duplication? As it stands, I have saved much duplication already, but it pains me to see the exact same code in three classes just so that they each subclass a different type of Activity.

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  • Obfuscator for .NET assembly (Maybe just a C++ obfuscator?)

    - by Pirate for Profit
    The software company I work for is using a ton of open source LGPL/BSD/MIT C++ code that we have written wrappers around to port "helper classes" into a .NET assembly, via C++/CLI. These libraries have wrapped old cryptic APIs into easy-to-use ones based on common sense, and will be very helpful for a lot of different tasks will be included in many future client's applications, and we might even license it to other software companies in the same field. So naturally we are tasked with looking into solutions for securing the code from prying eyes. What we're trying to do is stop the casual observer from seeing what's going on. Now I have hacked some crazy shit in EverQuest and other video games in my day so I know with enough tireless effort anything can be done. But we don't want to make it easy for whomever. To the point, besides the Visual Studio compiler's optimizations, is there's a C++ obfuscator or .NET assembly obfuscator (after it's been built o.O) or something that would scramble everything up, re-arrange data structures, string constants, etc. idk? And if such a thing exists, we'd be curious to know how that would impact performance, as some sections of code are time critical (funny saying that using a managed M$ framework).

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  • Repository layout and sparse checkouts

    - by chuanose
    My team is considering to move from Clearcase to Subversion and we are thinking of organising the repository like this: \trunk\project1 \trunk\project2 \trunk\project3 \trunk\staticlib1 \trunk\staticlib2 \trunk\staticlib3 \branches\.. \tags\.. The issue here is that we have lots of projects (1000+) and each project is a dll that links in several common static libraries. Therefore checking out everything in trunk is a non-starter as it will take way too long (~2 GB), and is unwieldy for branching. Using svn:externals to pull out relevant folders for each project doesn't seem ideal because it results in several working copies for each static library folder. We also cannot do an atomic commit if the changes span the project and some static libraries. Sparse checkouts sounds very suitable for this as we can write a script to pull out only the required directories. However when we want to merge changes from a branch back to the trunk we will need to first check out a full trunk. Wonder if there is some advice on 1) a better repository organization or 2) a way to merge over branch changes to a trunk working copy that is sparse?

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  • Why does the WCF 3.5 REST Starter Kit do this?

    - by Brandon
    I am setting up a REST endpoint that looks like the following: [WebInvoke(Method = "POST", UriTemplate = "?format=json", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json)] and [WebInvoke(Method = "DELETE", UriTemplate = "?token={token}&format=json", ResponseFormat = WebMessageFormat.Json)] The above throws the following error: UriTemplateTable does not support '?format=json' and '?token={token}&format=json' since they are not equivalent, but cannot be disambiguated because they have equivalent paths and the same common literal values for the query string. See the documentation for UriTemplateTable for more detail. I am not an expert at WCF, but I would imagine that it should map first by the HTTP Method and then by the URI Template. It appears to be backwards. If both of my URI templates are: ?token={token}&format=json This works because they are equivalent and it then appears to look at the HTTP Method where one is POST and the other is DELETE. Is REST supposed to work this way? Why are the URI Template Tables not being sorted first by HTTP Method and then by URI Template? This can cause some serious frustrations when 1 HTTP Method requires a parameter and another does not, or if I want to do optional parameters (e.g. if the 'format' parameter is not passed, default to XML).

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  • Do you ever make a code change and just test rather than trying to fully understand the change you'v

    - by Clay Nichols
    I'm working in a 12 year old code base which I have been the only developer on. There are times that I'll make a a very small change based on an intuition (or quantum leap in logic ;-). Usually I try to deconstruct that change and make sure I read thoroughly the code. However sometimes, (more and more these days) I just test and make sure it had the effect I wanted. (I'm a pretty thorough tester and would test even if I read the code). This works for me and we have surprisingly (compared to most software I see) few bugs escape into the wild. But what I'm wondering is whether this is just the "art" side of coding. Yes, in an ideal world you would exhaustively read every bit of code that your change modified, but I in practice, if you're confident that it only affects a small section of code, is this a common practice? I can obviously see where this would be a disastrous approach in the hands of a poor programmer. But then, I've seen programmers who ostensibly are reading the code and break stuff left and right (in their own code based which only they have been working on).

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  • Is it acceptable to wrap PHP library functions solely to change the names?

    - by Carson Myers
    I'm going to be starting a fairly large PHP application this summer, on which I'll be the sole developer (so I don't have any coding conventions to conform to aside from my own). PHP 5.3 is a decent language IMO, despite the stupid namespace token. But one thing that has always bothered me about it is the standard library and its lack of a naming convention. So I'm curious, would it be seriously bad practice to wrap some of the most common standard library functions in my own functions/classes to make the names a little better? I suppose it could also add or modify some functionality in some cases, although at the moment I don't have any examples (I figure I will find ways to make them OO or make them work a little differently while I am working). If you saw a PHP developer do this, would you think "Man, this is one shoddy developer?" Additionally, I don't know much (or anything) about if/how PHP is optimized, and I know that usually PHP performace doesn't matter. But would doing something like this have a noticeable impact on the performance of my application?

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  • Best practice for debug Asserts during Unit testing

    - by Steve Steiner
    Does heavy use of unit tests discourage the use of debug asserts? It seems like a debug assert firing in the code under test implies the unit test shouldn't exist or the debug assert shouldn't exist. "There can be only one" seems like a reasonable principle. Is this the common practice? Or do you disable your debug asserts when unit testing, so they can be around for integration testing? Edit: I updated 'Assert' to debug assert to distinguish an assert in the code under test from the lines in the unit test that check state after the test has run. Also here is an example that I believe shows the dilema: A unit test passes invalid inputs for a protected function that asserts it's inputs are valid. Should the unit test not exist? It's not a public function. Perhaps checking the inputs would kill perf? Or should the assert not exist? The function is protected not private so it should be checking it's inputs for safety.

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  • Import data from multiple CSV files to an Excel sheet

    - by Chetan
    I need to import data from 50 similar csv files to a single excel sheet. Is there any way to get only selected columns from each file and put them together in one sheet. Structure of my csv files: A few columns exactly same in all the files. (I want them to be in excel) then one column with same column name but different data which I want to place next to each other with different names in the excel sheet. I do not not want all other remaining columns from csv files. In short, read all csv files, get all the columns which are common to all csv & put in excel sheet. Now, take one column from each file which has the same header but different data and put one after the other in excel sheet with named from the csv file name. Leave remaining rest of the columns. Write excel sheet to a excel file. Initially I thought it can be easily done, but considering my programming skill in learning stage it is way difficult for me. Please help.

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  • Memory mapping of files and system cache behavior in WinXP

    - by Canopus
    Our application is memory intensive and deals with reading a large number of disk files. The total load can be more than 3 GB. There is a custom memory manager that uses memory mapped files to achieve reading of such a huge data. The files are mapped into the process memory space only when needed and with this the process memory is well under control. But what is observed is, with memory mapping, the system cache keeps on increasing until it occupies the available physical memory. This leads to the slowing down of the entire system. My question is how to prevent system cache from hogging the physical memory? I attempted to remove the file buffering (by using FILE_FLAG_NO_BUFFERING ), but with this, the read operations take considerable amount of time and slows down the application performance. How to achieve the scalability without sacrificing much on performance. What are the common techniques used in such cases? I dont have a good understanding of the WinXP OS caching behavior. Any good links explaining the same would also be helpful.

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  • jQuery / Loading content into div and changing url's (working but buggy)

    - by Bruno
    This is working, but I'm not being able to set an index.html file on my server root where i can specify the first page to go. It also get very buggy in some situations. Basically it's a common site (menu content) but the idea is to load the content without refreshing the page, defining the div to load the content, and make each page accessible by the url. One of the biggest problems here it's dealing with all url situations that may occur. The ideal would be to have a rel="divToLoadOn" and then pass it on my loadContent() function... so I would like or ideas/solutions for this please. Thanks in advance! //if page comes from URL if(window.location.hash != ''){ var url = window.location.hash; url = '..'+url.substr(1, url.length); loadContent(url); } //if page comes from an internal link $("a:not([target])").click(function(e){ e.preventDefault(); var url = $(this).attr("href"); if(url != '#'){ loadContent($(this).attr("href")); } }); //LOAD CONTENT function loadContent(url){ var contentContainer = $("#content"); //set load animation $(contentContainer).ajaxStart(function() { $(this).html('loading...'); }); $.ajax({ url: url, dataType: "html", success: function(data){ //store data globally so it can be used on complete window.data = data; }, complete: function(){ var content = $(data).find("#content").html(); var contentTitle = $(data).find("title").text(); //change url var parsedUrl = url.substr(2,url.length) window.location.hash = parsedUrl; //change title var titleRegex = /(.*)<\/title/.exec(data); contentTitle = titleRegex[1]; document.title = contentTitle; //renew content $(contentContainer).fadeOut(function(){ $(this).html(content).fadeIn(); }); }); }

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  • Develop multiple very similar projects at once

    - by Raveren
    I am developing a semi-complicated site that is available in several countries at once. Much effort has been put in to make the code bases as similar as possible to one another and ultimately only the config file and some representational data will differ between them. Each project has its own SVN repository which maps directly to a live test site. That part is handled by the IDE we use to work. Now I am in need to create a some sort of system to keep all these projects in sync. The best theoretical solution so far is to create a local hook script that would fire on committing and Merge the committed files from the project that is being committed to all other projects Optionally upload them to the live site, replacing previous files The first problem is that I don't know how I would do the merging - I guess it would be like applying a SVN patch or something. The second is if I do not want to upload the changes to the live server, how would I go about synching the live and local code bases (replace older files?). I am posting this question, not going through the potentially huge trouble of solving the aforementioned problems myself is that I believe this is a pretty common situation and someone would already have a solution and others may benefit from the answers in the future. Lastly, I'm on windows7, develop PHP and use tortoiseSVN.

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  • Django Many-to-Many Question

    - by DZ
    My questions seems like a common problem that when I have seen any questions on it is never really asked right or not answered. So Im going to try to get the question right, and maybe someone knows how to resolve the issue, or correct my understanding. The problem: When you have a many-to-many relation ship (related_name not through) and you are trying to use the admin interface you are required to input one of the rleationships even though it does not have to exsist for you to create the first entry. Meaning you have to assign a group to an event to create the group. Wow that sounds complicated. So I can see why the question is not getting answered. Lets try the non code explanation example... First and important versions: Django 1.1.1 Phython 2.6 So I have a model where I created a many-to-many realtionship and Im using the related_name Im creating an app that is an event organizer, for simplicty lets say events although they could be anytype). For this first post Im going to stay away from the code and just try to explain. A few keys: (explaining comment) ** - many-to-many So in the model we have 1) The Main Event (this is main model) 2) Groups (link to events and their can be many events for a group) a) Events** I have simplified this example a little becuase I recognize that what does it matter. Just create the event first... But there are specific varations where that will not work. What the many-to-many related_name does it created another table with the indecies of the two other tables. Nothing says that this extra table HAS to be populated. Becuase if I look in the database and work within myPHPadmin I can create a group with out registering an event, since the connection between the two is a seperate table the DB does not care. How do I make the admin interface this realize it? Ok I know thats a lot so I hope I have explained it clearly. Thank you anyone for your comments/thoughts/advice

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  • What is the standard way to bundle OSGi dependent libraries?

    - by Chris
    Hi, I have a project that references a number of open source libraries, some new, some not so new. That said, they are all stable and I wish to stick with my chosen versions until I have time to migrate to the newer versions (I tested hsqldb 2.0 yesterday and it contains many api changes). One of the libraries I have wish to embed is Jasper Reports, but as you all surely know, it comes with a mountain of supporting jar files and I have only need a subset of the mountain (known) therefore I am planning to custom bundle all of my dependant libraries. So: Does everyone custom-make their own OSGi bundles for open-source libraries they are using or is there a master source of OSGi versions of common libraries? Also, I was thinking that it would be far simpler for each of my bundles simply to embed their dependent jars within the bundle itself. Is this possible? If I choose to embed the 3rd party foc libraries within a bundle, I assume I will need to produce 2 jar files, one without the embedded libraries (for libraries to be loaded via the classpath via standard classloader), and one osgi version that includes the embedded libraryy, therefore should I choose a bundle name like this <<myprojectname>>-<<subproject>>-osgi-.1.0.0.jar ? If I cannot embed the open source libraries and choose to custom bundle the open source libraries (via bnd), should I choose a unique bundle name to avoid conflict with a possible official bundle? e.g. <<myprojectname>>-<<3rdpartylibname>>-<<3rdpartylibversion>>.jar ? My non-OSGi enabled project currently scans for custom plugins via scanning the META-INF folders in my various plugin jars via Service.providers(...). If I go OSGi, will this mechanism still work?

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  • looking for advise on importing excel into mysql with php

    - by Ole Media
    Alright, see if I can pick your brains from you all. I'm currently working on a project where all the information comes from different clients, the only thing in common is that the received data is done with excel. The excel spread sheet that they present is just a bunch of references and codes, and the problem than I'm facing is that I need the references and codes to be entered in certain format in order for the website to work. The perfect situation will be to go to each client and teach how I would need the data, but I can't do that because of the large number of clients, and more importantly I will be interrupting their work flow. Each client has its own codes and reference model and they are not willing to change their process The good news is that there is a standard pattern for the codes, but I'm talking close to 200 thousand codes with a bunch of combination. They way that we are currently solving the problem is that we have a person who checks each excel sheet received, runs a few macros, and manually fixes those codes in which the macro was not able to fix. The person that is doing this, is already burn out and frustrated and I would like to automatize this process with php. Suggestions?

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  • Define "Validation in the Model"

    - by sunwukung
    There have been a couple of discussions regarding the location of user input validation: http://stackoverflow.com/questions/659950/should-validation-be-done-in-form-objects-or-the-model http://stackoverflow.com/questions/134388/where-do-you-do-your-validation-model-controller-or-view These discussions were quite old, so I wanted to ask the question again to see if anyone had any fresh input. If not, I apologise in advance. If you come from the Validation in the Model camp - does Model mean OOP representation of data (i.e. Active Record/Data Mapper) as "Entity" (to borrow the DDD terminology) - in which case you would, I assume, want all Model classes to inherit common validation constraints. Or can these rules simply be part of a Service in the Model - i.e. a Validation service? For example, could you consider Zend_Form and it's validation classes part of the Model? The concept of a Domain Model does not appear to be limited to Entities, and so validation may not necessarily need to be confined to this Entities. It seems that you would require a lot of potentially superfluous handing of values and responses back and forth between forms and "Entities" - and in some instances you may not persist the data recieved from user input, or recieve it from user input at all.

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  • breaking datetime into constituent parts ASP.NET MVC form

    - by nick
    hi guys, i have searched the web relentlessly for this and have not found anything - which is surprising because i would think it is such a common scenario! Basically, on my model i have a DateTime field which i wish the user to populate through a form. I am using the Html helper to render all other parts of the form (along with validation) So this question is in two parts... Html Helper Firstly, is there any way to use the Html helper to split the DateTime field to be rendered as the three constituent parts of a date: day, month, year (since i do not care about the time part). This could be rendered as text boxes, drop down lists or a combination of both. Model Binding And then when the form is posted, what is the best approach for binding back up to the model? I have seen Scott Hanselmann's solution to this, but it seems a little bloated for what i need - i was hoping for a slightly more elegant solution. Is it recommended to extend DefaultModelBinder and set that as default binder (since all dates would be handled in this way) or write a class that implements IModelBionder and set it as the default binder for the DateTime type? Thanks for all the help in advance :-) i'm loving MVC but it's infuriating me that something so trivial is causing so much headaches!

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  • "Abstract static" method - how?

    - by polyglot
    There are already several SO questions on why there is not abstract static method/field as such, but I'm wondering about how one would go about implementing the following psuedo-code: class Animal { abstract static int getNumberOfLegs(); // not possible } class Chicken inherits Animal { static int getNumberOfLegs() { return 2; } class Dog inherits Animal { static int getNumberOfLegs() { return 4; } Here is the problem: Assuming that I want make sure that every class that inherits Animal to contain getNumberOfLegs() method (i.e. almost like an interface, except I do want the abstract class to implement several methods that are common to all child classes, hence pure interface does not work here). getNumberOfLegs() obviously should be a static method (assuming that in a perfect world we dont' have crippled chicken and dogs so getNumberOfLegs is not instance-dependent). Without an "abstract static" method/field, one can either leave the method out from Animal class, then there is the risk that some child class do not have that method. Or one can make getNumberOfLegs an instance method, but then one would have to instantiate a class to find out how many legs that animal has - even though it is not necessary. How do one usually go about implementing this situation?

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  • Best practice to hide/encrypt email adress in webpage

    - by Sebi
    I couldn't find a similar question, that's why here it is: Whats the best way to hide or encrypt an email link in a website, so that a crawler can't read it, but the user can nevertheless click it? I don't want to conufse the users by typing the email like this: john (at) mail.com or similar ways. (and i think this kind of links can nevertheless read by crawlers?) I also tried things like that: <script>// <![CDATA[eval(unescape('%76%61%72%20%73%3D%27%61%6D%6C%69%6F%74%72%3A%62%61%40%65%64%61%6E%6F%6C%2E%69%27%3B%76%61%72%20%72%3D%27%27%3B%66%6F%72%28%76%61%72%20%69%3D%30%3B%69%3C%73%2E%6C%65%6E%67%74%68%3B%69%2B%2B%2C%69%2B%2B%29%7B%72%3D%72%2B%73%2E%73%75%62%73%74%72%69%6E%67%28%69%2B%31%2C%69%2B%32%29%2B%73%2E%73%75%62%73%74%72%69%6E%67%28%69%2C%69%2B%31%29%7D%64%6F%63%75%6D%65%6E%74%2E%77%72%69%74%65%28%27%3C%61%20%68%72%65%66%3D%22%27%2B%72%2B%27%22%3E%4F%62%65%72%70%61%72%6C%65%69%74%65%72%3C%2F%61%3E%27%29%3B'))]]></script> but i heard this can also be read by crawler and it isn't really good practices are ther any common approaches?

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  • entity framework navigation property further filter without loading into memory

    - by cellik
    Hi, I've two entities with 1 to N relation in between. Let's say Books and Pages. Book has a navigation property as Pages. Book has BookId as an identifier and Page has an auto generated id and a scalar property named PageNo. LazyLoading is set to true. I've generated this using VS2010 & .net 4.0 and created a database from that. In the partial class of Book, I need a GetPage function like below public Page GetPage(int PageNumber) { //checking whether it exist etc are not included for simplicity return Pages.Where(p=>p.PageNo==PageNumber).First(); } This works. However, since Pages property in the Book is an EntityCollection it has to load all Pages of a book in memory in order to get the one page (this slows down the app when this function is hit for the first time for a given book). i.e. Framework does not merge the queries and run them at once. It loads the Pages in memory and then uses LINQ to objects to do the second part To overcome this I've changed the code as follows public Page GetPage(int PageNumber) { MyContainer container = new MyContainer(); return container.Pages.Where(p=>p.PageNo==PageNumber && p.Book.BookId==BookId).First(); } This works considerably faster however it doesn't take into account the pages that have not been serialized to the db. So, both options has its cons. Is there any trick in the framework to overcome this situation. This must be a common scenario where you don't want all of the objects of a Navigation property loaded in memory when you don't need them.

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  • Recreating a workflow instance with the same instance id

    - by Miron Brezuleanu
    We have some objects that have an associated workflow instance. The objects are identified with a GUID, which is also the GUID of the workflow instance associated with the object. We need to restart (see NOTE 3 for the meaning of 'restart') the workflow instance if the workflow definition changed (there is no state in the workflow itself and it is written to support restarting in this manner). The restarting is performed by calling Terminate on the WorkflowInstance, then recreating the instance with the same GUID. The weird part is that this works every other attempt (odd attempts - the workflow is stopped, but for some reason doesn't restart, even attempt - the already terminated workflow is recreated and started successfully). While I admit that using 'second hand' GUIDs is a sign of extraordinary cheapness (and something we plan to change), I'm wondering why this isn't working. Any ideas? NOTES: The terminated workflow instance is passivated (waiting for a notification) at the time of the termination. The Terminate call successfully deletes the data persisted in the database for that instance. We're using 'restarting' with a meaning that's less common in the context of WF - not restarting a passivated instance, but force the workflow to start again from the beginning of its definition. Thanks!

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  • Monads with Join() instead of Bind()

    - by MathematicalOrchid
    Monads are usually explained in turns of return and bind. However, I gather you can also implement bind in terms of join (and fmap?) In programming languages lacking first-class functions, bind is excruciatingly awkward to use. join, on the other hand, looks quite easy. I'm not completely sure I understand how join works, however. Obviously, it has the [Haskell] type join :: Monad m = m (m x) - m x For the list monad, this is trivially and obviously concat. But for a general monad, what, operationally, does this method actually do? I see what it does to the type signatures, but I'm trying to figure out how I'd write something like this in, say, Java or similar. (Actually, that's easy: I wouldn't. Because generics is broken. ;-) But in principle the question still stands...) Oops. It looks like this has been asked before: Monad join function Could somebody sketch out some implementations of common monads using return, fmap and join? (I.e., not mentioning >>= at all.) I think perhaps that might help it to sink in to my dumb brain...

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