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  • Multiple layouts in rails [Newbie Q]

    - by BriteLite
    Hi. As a newb, I decided to build a "home inventory" application. I am now stuck on how to programmatically select a layout based on what type of item it is when viewing it in a browser. According to my planning, so far I should have created a few models to represent types of items I can find in my home: Furniture, Electronics and Books. class Book < ActiveRecord::Base end class Furniture < ActiveRecord::Base end class Electronic < ActiveRecord::Base end Now the Books model has things like isbn, pages, address, and category. Furniture model has things like color, price, address, and category. Electronics has things like name, voltage, address, and category. Here is where I got confused. I know the property address is going to be the same for all of them. I also know that, I will need to create multiple "layouts" for 3 different types of items to show the different properties of said items with appropriate graphics and stylesheets. But how will I go about deciding which category the item is so I can determine which layout to render. According to me, this is how I will do it: class DisplayController < ApplicationController def display @item = Params[:item] if @item.category = "electronics" render :layout => 'electronics' end end In my routes.rb map.display ':item', :controller => 'display', :action => 'display' I only seem to have one concern with this, I probably will add a lot of categories later on and think there should be a more DRY-esque way of dealing, rather than hardcoding them. I understand that I need to add into my layout html tags to display relevant information for that particular category. ----Questions---- Is this the right way to approach this type of problem. Will this approach be compatible when I decide to add a gem like *thinking_sphinx* to run search. What issues do you see with my approach and how can I make it better. I was reading something about "Polymorphic Assoc", does that apply in this case, since category exist for all items? Also, I was trying to get a routes to render a URL like "http://localhost/living-room-tv"

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  • Resultset (getter/setter class) object not deleting old values at 2nd Time execution in swin

    - by user2384525
    I have summarizeData() method and called so many time for value retrieve. but first time is working file but 2nd time execution value is increasing in HashMap. void summarizeData() { HashMap outerMap = new HashMap(); ArrayList list = new ArrayList(dataClass.getData()); for (int indx = 0; indx < list.size(); indx++) { System.out.println("indx : " + indx); Resultset rs = new Resultset(); rs = (Resultset) list.get(indx); if (rs != null) { int id = rs.getTestCaseNumber(); if (id > 0) { Object isExists = outerMap.get(id); if (isExists != null) { //System.out.println("found entry so updating"); Resultset inRs = new Resultset(); inRs = (Resultset) isExists; if (inRs != null) { int totExec = inRs.getTestExecution(); int totPass = inRs.getTestCasePass(); int totFail = inRs.getTestCaseFail(); // System.out.println("totE :" + totExec + " totP:" + totPass + " totF:" + totFail); int newRsStat = rs.getTestCasePass(); if (newRsStat == 1) { totPass++; inRs.setTestCasePass(totPass); } else { totFail++; inRs.setTestCaseFail(totFail); } totExec++; // System.out.println("id : "+id+" totPass: "+totPass+" totFail:"+totFail); // System.out.println("key : " + id + " val : " + inRs.getTestCaseNumber() + " " + inRs.getTestCasePass() + " " + inRs.getTestCaseFail()); inRs.setTestExecution(totExec); outerMap.put(id, inRs); } } else { // System.out.println("not exist so new entry" + " totE:" + rs.getTestExecution() + " totP:" + rs.getTestCasePass() + " totF:" + rs.getTestCaseFail()); outerMap.put(id, rs); } } } else { System.out.println("rs null"); } } Output at 1st Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :1 totP:1 totF:0 indx : 11 totE :1 totP:1 totF:0 indx : 12 totE :1 totP:1 totF:0 indx : 13 totE :1 totP:1 totF:0 indx : 14 totE :1 totP:1 totF:0 indx : 15 totE :1 totP:1 totF:0 indx : 16 totE :1 totP:1 totF:0 indx : 17 totE :1 totP:1 totF:0 indx : 18 totE :1 totP:1 totF:0 indx : 19 totE :1 totP:1 totF:0 Output at 2nd Execution: indx : 0 indx : 1 indx : 2 indx : 3 indx : 4 indx : 5 indx : 6 indx : 7 indx : 8 indx : 9 indx : 10 totE :2 totP:2 totF:0 indx : 11 totE :2 totP:2 totF:0 indx : 12 totE :2 totP:2 totF:0 indx : 13 totE :2 totP:2 totF:0 indx : 14 totE :2 totP:2 totF:0 indx : 15 totE :2 totP:2 totF:0 indx : 16 totE :2 totP:2 totF:0 indx : 17 totE :2 totP:2 totF:0 indx : 18 totE :2 totP:2 totF:0 indx : 19 totE :2 totP:2 totF:0 while i required same output on every execution.

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  • SAX parser does not resolve filename

    - by phantom-99w
    Another day, another strange error with SAX, Java, and friends. I need to iterate over a list of File objects and pass them to a SAX parser. However, the parser fails because of an IOException. However, the various File object methods confirm that the file does indeed exist. The output which I get: 11:53:57.838 [MainThread] DEBUG DefaultReactionFinder - C:\project\trunk\application\config\reactions\TestReactions.xml 11:53:57.841 [MainThread] ERROR DefaultReactionFinder - C:\project\trunk\application\config\reactions\null (The system cannot find the file specified) So the problem is obviously that null in the second line. I've tried nearly all variations of passing the file as a parameter to the parser, including as a String (both from getAbsolutePath() and entered by hand), as a URI and, even more weirdly, as a FileInputStream (for this I get the same error, except that the entire relative path gets reported as null, so C:\project\trunk\null). All that I can think of is that the SAXParserFactory is incorrectly configured. I have no idea what is wrong, though. Here is the code concerned: SAXParserFactory factory = SAXParserFactory.newInstance(); factory.setValidating(true); try { parser = factory.newSAXParser(); } catch (ParserConfigurationException e) { throw new InstantiationException("Error configuring an XML parser. Given error message: \"" + e.getMessage() + "\"."); } catch (SAXException e) { throw new InstantiationException("Error creating a SAX parser. Given error message: \"" + e.getMessage() + "\"."); } ... for (File f : fileLister.getFileList()) { logger.debug(f.getAbsolutePath()); try { parser.parse(f, new ReactionHandler(input)); //FileInputStream fs = new FileInputStream(f); //parser.parse(fs, new ReactionHandler(input)); //fs.close(); } catch (IOException e) { logger.error(e.getMessage()); throw new ReactionNotFoundException("An error occurred processing file \"" + f + "\"."); } ... } I have made no special provisions to provide a custom SAX parser implementation: I use the system default. Any help would be greatly appreciated!

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  • Remote XP -> Win98 WMI Connection

    - by Logan Young
    I've asked this on Technet, but because Win98 is no longer supported, I can't get any decent information, I was hoping there might be some "old school" developers here who might be able to help me. There is an application that we use a lot at work. This application should run 8am-5pm with as little interruption as possible. Most of the computers where this application runs are using Win98, and we have no way to upgrade them because we can't buy new hardware at the moment. My computer is running WinXP, so I thought of a way to make sure that this application runs all the time: The idea I had was to develop a Windows Service that executes a VBScript file that contains a WMI query to get a list of processes from each computer. Each list is then examined, and, depending on whether or not the target application is running, it will either do nothing, or it will execute another VBScript file that contains a WMI query that will be used to start the target application remotely. I later found a way to do this all with 1 VBScript file (see code below) My problem is in the remote connection to the target computers. I've installed WMI Core 1.5 on them, but every time I try the remote connection, I get the following: The remote server is unavailable or does not exist: 'GetObject' VBScript runtime error 800A01CE I've done some research, and all I've found is info about DCOM Config and Windows Firewall, but Win98 doesn't have either of these. ' #### Variables and constants #### Const HIDDEN_WINDOW = 12 Dim T ' #### End Variables and constants #### Main() Sub Main() ' #### Get Process information from WMI Computer = "." Set WMI = GetObject("winmgmts:" & _ "{ImpersonationLevel=Impersonate}!\\" & Computer & "\root\cimv2") Set Settings = WMI.ExecQuery("SELECT * FROM Win32_Process") For Each Process In Settings ' #### If the application is found to be running, set a value to indicate this If Process.Name = "NOTEPAD.EXE" Then T = True End If Next ' #### T will only have a value if the application is not running. We therefore ' #### evaluate it to determine if it has a value or not. If not, start the application If Not T Then 'MsgBox("Application not found.") Set Startup = WMI.Get("Win32_ProcessStartup") Set Config = Startup.SpawnInstance_ Config.ShowWindow = HIDDEN_WINDOW Set Process = GetObject("winmgmts:root\cimv2:Win32_Process") errReturn = Process.Create(_ "C:\Windows\notepad.exe", null, Config, intProcessID) End If End Sub This uses WMI to get the list of processes from the local computer and, if the target application is running, it'll do nothing, otherwise it'll forcefully start the target application. The problem is that this works only if I specify the local comuter, if I target another computer, I get the error mentioned above. Does anyone have any ideas? Thanks in advance for the help!

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  • Closing a process that open in code

    - by AmirHossein
    I create a WordTemplate with some placeholders for field,in code I insert value in this placeholders and show it to user. protected void Button1_Click(object sender, EventArgs e) { string DocFilePath = ""; //string FilePath = System.Windows.Forms.Application.StartupPath; object fileName = @"[...]\asset\word templates\FormatPeygiri1.dot"; DocFilePath = fileName.ToString(); FileInfo fi = new FileInfo(DocFilePath); if (fi.Exists) { object readOnly = false; object isVisible = true; object PaperNO = "PaperNO"; object PaperDate = "PaperDate"; object Peyvast = "Peyvast"; object To = "To"; object ShoName = "ShoName"; object DateName = "DateName"; Microsoft.Office.Interop.Word.Document aDoc = WordApp.Documents.Open(ref fileName, ref missing, ref readOnly, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref isVisible, ref isVisible, ref missing, ref missing, ref missing); WordApp.ActiveDocument.FormFields.get_Item(ref PaperNO).Result = TextBox_PaperNO.Text; string strPaperDate = string.Format("{0}/{1}/{2}", PersianDateTimeHelper.GetPersainDay(DateTimePicker_PaperDate.SelectedDate), PersianDateTimeHelper.GetPersainMonth(DateTimePicker_PaperDate.SelectedDate), PersianDateTimeHelper.GetPersainYear(DateTimePicker_PaperDate.SelectedDate)); WordApp.ActiveDocument.FormFields.get_Item(ref PaperDate).Result = strPaperDate; WordApp.ActiveDocument.FormFields.get_Item(ref Peyvast).Result = TextBox_Peyvast.Text; WordApp.ActiveDocument.FormFields.get_Item(ref To).Result = TextBox_To.Text; ; WordApp.ActiveDocument.FormFields.get_Item(ref ShoName).Result = TextBox_ShoName.Text; string strDateName = string.Format("{0}/{1}/{2}", PersianDateTimeHelper.GetPersainDay(DateTimePicker_DateName.SelectedDate), PersianDateTimeHelper.GetPersainMonth(DateTimePicker_DateName.SelectedDate), PersianDateTimeHelper.GetPersainYear(DateTimePicker_DateName.SelectedDate)); WordApp.ActiveDocument.FormFields.get_Item(ref DateName).Result = strDateName; aDoc.Activate(); WordApp.Visible = true; aDoc = null; WordApp = null; } else { MessageBox1.Show("File Not Exist!"); } it work good and successfully! but when a user close the Word,her Process not closed and exists in Task Manager Process list. this process name is WINWORD.exe I know that I can close process whit code [process.Kill()] but I don't know which process that I should to kill. if I want to kill all process with name [WINWORD.exe] all Word window closed.but I want to close specific Word window and kill process that I opened. How to do it?

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  • Need Help with Page Life Cycle(I think it is screwing me up)

    - by chobo2
    Hi I have dragged a empty asp.net table onto my webform. I generate all the rows in the code behind those. Now my table gets filled up and has dropdown lists. When the user hits save I go through all the rows and update the values from the dropdownlist in the db. This works all great. However if 2 columns have each have "Present" then those 2 columns should be not be shown anymore and 2 new columns get put in its place with other dropdown lists. This all works. However you have to refresh the entire page to for the 2 columns that should go away to go away. So what I tried to do is at the end of the button click event. Clear the whole table and then regenerate it. However when I do this then my values are not saved to the database anymore for whatever reason. if (IsPostBack == false) { // check if dummy variables exist in db- If true just generate tables with values in db. If not generate them. } else { // grab the values from the database // generate tables with the values } btn click event { go through all rows in table(foreach loop) update each column in the database with cells in each row. while in foreach loop. //done } So this is how it goes and it works expect(all correct values are saved) the table is just not updated to the user. Does not work if (IsPostBack == false) { // same code as above } // if postback is true do nothing. By the time it gets to the click event it says there is zero rows in the table so nothing happens. btn click event { // same code } Fails also. if (IsPostBack == false) { // same code as above } else { // same code as above but moved into its own method. gernerateTable(); } btn click event { // update all rows // once done clear the Tables rows // call generateTable() } This last one does nothing as for some reason it does not update anything. I don't understand why. So what am I doing wrong with this life cycle something in my process is wrong. The code works just not when I want the table to be updated right away.

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  • Sort array by two specifics values in PHP

    - by Roger
    The folks have already showed me how to sort an array by a specific value using usort and a fallback function in PHP. What if this specifc value doesn't exist and we have to use two values? in the example bellow the values [4] and [5]... In other words, I want to do this: order all objects numericaly by the fith value of each object from the highest to the lowest, and addicionally, for those objects that have the fifht value is empty (in the examplem '-'), order them by the fourth value. Array( [0] => Array( [0] => links-patrocinados [1] => adwords [2] => 0,5 [3] => R$92,34 [4] => 823000 [5] => 49500 ) [1] => Array( [0] => adwords [1] => google adwords como funciona [2] => 0,38 [3] => R$0,20 [4] => 480 [5] => 480 ) [2] => Array( [0] => links-patrocinados [1] => adword [2] => 0,39 [3] => R$58,77 [4] => 49500 [5] => 2900 ) [3] => Array( [0] => agencia [1] => agencias viagens espanholas [2] => - [3] => R$0,20 [4] => 58 [5] => - ) [4] => Array( [0] => agencia [1] => era agencia imobiliaria [2] => - [3] => R$0,20 [4] => 73 [5] => - ) )

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  • Moving Function With Arguments To RequireJS

    - by Jazimov
    I'm not only relatively new to JavaScript but also to RequireJS (coming from string C# background). Currently on my web page I have a number of JavaScript functions. Each one takes two arguments. Imagine that they look like this: functionA(x1, y1) { ... } functionB(x2, y2) { ... } functionC(x3, y3) { ... } Currently, these functions exist in a tag on my HTML page and I simply call each as needed. My functions have dependencies on KnockoutJS, jQuery, and some other JS libraries. I currently have Script tags that synchronously load those external .js dependencies. But I want to use RequireJS so that they're loaded asynchronously, as needed. To do this, I plan to move all three functions above into an external .js file (a type of AMD "module") called MyFunctions.js. That file will have a define() call (to RequireJS's define function) that will look something like this: define(["knockout", "jquery", ...], function("ko","jquery", ...) {???} ); My question is how to "wrap" my functionA, functionB, and functionC functions where the ??? is above so that I can use those functions on my page as needed. For example, in the onclick event handler for a button on my HTML page, I would want to call functionA and pass two it two arguments; same for functionB and functionC. I don't fully understand how to expose those functions when they're wrapped in a define that itself is located in an external .js file. I know that define assures that my listed libraries are loaded asynchronously before the callback function is called, but after that's done I don't understand how the web page's script tags would use my functions. Would I need to use require to ensure they're available, such as: require(["myfunctions"],function({not sure what to put here})] I think I understand the basics of RequireJS but I don't understand how to wrap my functions so that they're in external .js files, don't pollute the global namespace, and yet can still be called from the main page so that arguments can be passed to them. I imagine they're are many ways to do this but in reviewing the RequireJS docs and some videos out there, I can't say I understand how... Thank you for any help.

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  • Finding open contiguous blocks of time for every day of a month, fast

    - by Chris
    I am working on a booking availability system for a group of several venues, and am having a hard time generating the availability of time blocks for days in a given month. This is happening server-side in PHP, but the concept itself is language agnostic -- I could be doing this in JS or anything else. Given a venue_id, month, and year (6/2012 for example), I have a list of all events occurring in that range at that venue, represented as unix timestamps start and end. This data comes from the database. I need to establish what, if any, contiguous block of time of a minimum length (different per venue) exist on each day. For example, on 6/1 I have an event between 2:00pm and 7:00pm. The minimum time is 5 hours, so there's a block open there from 9am - 2pm and another between 7pm and 12pm. This would continue for the 2nd, 3rd, etc... every day of June. Some (most) of the days have nothing happening at all, some have 1 - 3 events. The solution I came up with works, but it also takes waaaay too long to generate the data. Basically, I loop every day of the month and create an array of timestamps for each 15 minutes of that day. Then, I loop the time spans of events from that day by 15 minutes, marking any "taken" timeslot as false. Remaining, I have an array that contains timestamp of free time vs. taken time: //one day's array after processing through loops (not real timestamps) array( 12345678=>12345678, // <--- avail 12345878=>12345878, 12346078=>12346078, 12346278=>false, // <--- not avail 12346478=>false, 12346678=>false, 12346878=>false, 12347078=>12347078, // <--- avail 12347278=>12347278 ) Now I would need to loop THIS array to find continuous time blocks, then check to see if they are long enough (each venue has a minimum), and if so then establish the descriptive text for their start and end (i.e. 9am - 2pm). WHEW! By the time all this looping is done, the user has grown bored and wandered off to Youtube to watch videos of puppies; it takes ages to so examine 30 or so days. Is there a faster way to solve this issue? To summarize the problem, given time ranges t1 and t2 on day d, how can I determine the remaining time left in d that is longer than the minimum time block m. This data is assembled on demand via AJAX as the user moves between calendar months. Results are cached per-page-load, so if the user goes to July a second time, the data that was generated the first time would be reused. Any other details that would help, let me know. Edit Per request, the database structure (or the part that is relevant here) *events* id (bigint) title (varchar) *event_times* id (bigint) event_id (bigint) venue_id (bigint) start (bigint) end (bigint) *venues* id (bigint) name (varchar) min_block (int) min_start (varchar) max_start (varchar)

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  • In R, how do you get the best fitting equation to a set of data?

    - by Matherion
    I'm not sure wether R can do this (I assume it can, but maybe that's just because I tend to assume that R can do anything :-)). What I need is to find the best fitting equation to describe a dataset. For example, if you have these points: df = data.frame(x = c(1, 5, 10, 25, 50, 100), y = c(100, 75, 50, 40, 30, 25)) How do you get the best fitting equation? I know that you can get the best fitting curve with: plot(loess(df$y ~ df$x)) But as I understood you can't extract the equation, see Loess Fit and Resulting Equation. When I try to build it myself (note, I'm not a mathematician, so this is probably not the ideal approach :-)), I end up with smth like: y.predicted = 12.71 + ( 95 / (( (1 + df$x) ^ .5 ) / 1.3)) Which kind of seems to approximate it - but I can't help to think that smth more elegant probably exists :-) I have the feeling that fitting a linear or polynomial model also wouldn't work, because the formula seems different from what those models generally use (i.e. this one seems to need divisions, powers, etc). For example, the approach in Fitting polynomial model to data in R gives pretty bad approximations. I remember from a long time ago that there exist languages (Matlab may be one of them?) that do this kind of stuff. Can R do this as well, or am I just at the wrong place? (Background info: basically, what we need to do is find an equation for determining numbers in the second column based on the numbers in the first column; but we decide the numbers ourselves. We have an idea of how we want the curve to look like, but we can adjust these numbers to an equation if we get a better fit. It's about the pricing for a product (a cheaper alternative to current expensive software for qualitative data analysis); the more 'project credits' you buy, the cheaper it should become. Rather than forcing people to buy a given number (i.e. 5 or 10 or 25), it would be nicer to have a formula so people can buy exactly what they need - but of course this requires a formula. We have an idea for some prices we think are ok, but now we need to translate this into an equation.

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  • Objective-C memory management issue

    - by Toby Wilson
    I've created a graphing application that calls a web service. The user can zoom & move around the graph, and the program occasionally makes a decision to call the web service for more data accordingly. This is achieved by the following process: The graph has a render loop which constantly renders the graph, and some decision logic which adds web service call information to a stack. A seperate thread takes the most recent web service call information from the stack, and uses it to make the web service call. The other objects on the stack get binned. The idea of this is to reduce the number of web service calls to only those appropriate, and only one at a time. Right, with the long story out of the way (for which I apologise), here is my memory management problem: The graph has persistant (and suitably locked) NSDate* objects for the currently displayed start & end times of the graph. These are passed into the initialisers for my web service request objects. The web service call objects then retain the dates. After the web service calls have been made (or binned if they were out of date), they release the NSDate*. The graph itself releases and reallocates new NSDates* on the 'touches ended' event. If there is only one web service call object on the stack when removeAllObjects is called, EXC_BAD_ACCESS occurs in the web service call object's deallocation method when it attempts to release the date objects (even though they appear to exist and are in scope in the debugger). If, however, I comment out the release messages from the destructor, no memory leak occurs for one object on the stack being released, but memory leaks occur if there are more than one object on the stack. I have absolutely no idea what is going wrong. It doesn't make a difference what storage symantics I use for the web service call objects dates as they are assigned in the initialiser and then only read (so for correctness' sake are set to readonly). It also doesn't seem to make a difference if I retain or copy the dates in the initialiser (though anything else obviously falls out of scope or is unwantedly released elsewhere and causes a crash). I'm sorry this explanation is long winded, I hope it's sufficiently clear but I'm not gambling on that either I'm afraid. Major big thanks to anyone that can help, even suggest anything I may have missed?

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  • Approaches for Content-based Item Recommendations

    - by PartlyCloudy
    Hello, I'm currently developing an application where I want to group similar items. Items (like videos) can be created by users and also their attributes can be altered or extended later (like new tags). Instead of relying on users' preferences as most collaborative filtering mechanisms do, I want to compare item similarity based on the items' attributes (like similar length, similar colors, similar set of tags, etc.). The computation is necessary for two main purposes: Suggesting x similar items for a given item and for clustering into groups of similar items. My application so far is follows an asynchronous design and I want to decouple this clustering component as far as possible. The creation of new items or the addition of new attributes for an existing item will be advertised by publishing events the component can then consume. Computations can be provided best-effort and "snapshotted", which means that I'm okay with the best result possible at a given point in time, although result quality will eventually increase. So I am now searching for appropriate algorithms to compute both similar items and clusters. At important constraint is scalability. Initially the application has to handle a few thousand items, but later million items might be possible as well. Of course, computations will then be executed on additional nodes, but the algorithm itself should scale. It would also be nice if the algorithm supports some kind of incremental mode on partial changes of the data. My initial thought of comparing each item with each other and storing the numerical similarity sounds a little bit crude. Also, it requires n*(n-1)/2 entries for storing all similarities and any change or new item will eventually cause n similarity computations. Thanks in advance! UPDATE tl;dr To clarify what I want, here is my targeted scenario: User generate entries (think of documents) User edit entry meta data (think of tags) And here is what my system should provide: List of similar entries to a given item as recommendation Clusters of similar entries Both calculations should be based on: The meta data/attributes of entries (i.e. usage of similar tags) Thus, the distance of two entries using appropriate metrics NOT based on user votings, preferences or actions (unlike collaborative filtering). Although users may create entries and change attributes, the computation should only take into account the items and their attributes, and not the users associated with (just like a system where only items and no users exist). Ideally, the algorithm should support: permanent changes of attributes of an entry incrementally compute similar entries/clusters on changes scale something better than a simple distance table, if possible (because of the O(n²) space complexity)

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  • DataGridView live display of datatable using virtual mode

    - by Chris
    I have a DataGridView that will display records (log entries) from a database. The amount of records that can exist at a time is very large. I would like to use the virtual mode feature of the DataGridView to display a page of data, and to minimize the amount of data that has to be transferred across a network at a given time. Polling for data is out of the question. There will be several clients running at a time, all of which are on the same network and viewing the records. If they all poll for data, the network will run very slowly. The data is read-only to the user; they won't be able to edit any of it, just view it. I need to know when updates occur in the database, and I need to update the screen with those updates accordingly using virtual mode. If a page of data a user is viewing contains data that has change, he/she will see those updates on that page. If updates were made to data in the database, but not in the data the user is viewing, then not much really changes on the user screen (Maybe just the scroll bar if records were added or removed). My current approach is using SQL server change tracking with the sync framework. Each client has a local SQL Server CE instance and database file that is kept in sync with the main database server. I use the information from the synchronization event to see if any changes were made to the main database and were sync'ed to the client. I need to use the DataGridView virtual mode here because I can't have thousands of records loaded into the DataGridView at once, otherwise memory usage goes through the roof. The main challenge right now is knowing how to use virtual mode to provide a seamless experience to the user by allowing them to scroll up and down through the records, and also have records update on the fly without interfering with the user inappropriately. Has anybody dealt with this issue before, and if so, where I can see how they did it? I've gone through some of the MSDN documentation and examples on virtual mode. So far, I haven't found documentation and/or examples on their site that explains how to do what I am trying to accomplish.

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  • Javascript to add cdata section on the fly?

    - by Chris G.
    I'm having trouble with special characters that exist in an xml node attribute. To combat this, I'm trying to render the attributes as child nodes and, where necessary, using cdata sections to get around the special characters. The problem is, I can't seem to get the cdata section appended to the node correctly. I'm iterating over the source xml node's attributes and creating new nodes. If the attribute.name = "description" I want to put the attribute.text() in a cdata section and append the new node. That's where I jump the track. // newXMLData is the new xml document that I've created in memory for (var ctr =0;ctr< this.attributes.length;ctr++){ // iterate over the attributes if( this.attributes[ctr].name =="Description"){ // if the attribute name is "Description" add a CDATA section var thisNodeName = this.attributes[ctr].name; newXMLDataNode.append("<"+thisNodeName +"></"+ thisNodeName +">" ); var cdata = newXMLData.createCDATASection('test'); // here's where it breaks. } else { // It's not "Description" so just append the new node. newXMLDataNode.append("<"+ this.attributes[ctr].name +">" + $(this.attributes[ctr]).text() + "</"+ this.attributes[ctr].name +">" ); } } Any ideas? Is there another way to add a cdata section? Here's a sample snippet of the source... <row pSiteID="4" pSiteTile="Test Site Name " pSiteURL="http://www.cnn.com" ID="1" Description="<div>blah blah blah since June 2007.&amp;nbsp; T<br>&amp;nbsp;<br>blah blah blah blah&amp;nbsp; </div>" CreatedDate="2010-09-20 14:46:18" Comments="Comments example.&#10;" > here's what I'm trying to create... <Site> <PSITEID>4</PSITEID> <PSITETILE>Test Site Name</PSITETILE> <PSITEURL>http://www.cnn.com</PSITEURL> <ID>1</ID> <DESCRIPTION><![CDATA[<div>blah blah blah since June 2007.&amp;nbsp; T<br>&amp;nbsp;<br>blah blah blah blah&amp;nbsp; </div ]]></DESCRIPTION> <CREATEDDATE>2010-09-20 14:46:18</CREATEDDATE> <COMMENTS><![CDATA[ Comments example.&#10;]]></COMMENTS> </Site>

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  • making a password-only auth with bcrypt and mongoose

    - by user3081123
    I want to create service that let you login only with password. You type a password and if this password exists - you are logged in and if it's not - username is generated and password is encrypted. I'm having some misunderstandings and hope someone would help me to show where I'm mistaken. I guess, it would look somewhat like this in agularjs First we receive a password in login controller. $scope.signup = function() { var user = { password: $scope.password, }; $http.post('/auth/signup', user); }; Send it via http.post and get in in our node server file. We are provided with a compare password bcrypt function userSchema.methods.comparePassword = function(candidatePassword, cb) { bcrypt.compare(candidatePassword, this.password, function(err, isMatch) { if (err) return cb(err); cb(null, isMatch); }); }; So right now we are creating function to catch our http request app.post('/auth/signup', function(req, res, next) { Inside we use a compair password function to realize if such password exists or not yet. So we have to encrypt a password with bcrypt to make a comparison First we hash it same way as in .pre var encPass; bcrypt.genSalt(10, function(err, salt) { if (err) return next(err); bcrypt.hash(req.body.password, salt, function(err, hash) { if (err) return next(err); encPass=hash; )}; )}; We have encrypted password stored in encPass so now we follow to finding a user in database with this password User.findOne({ password: encPass }, function(err, user) { if (user) { //user exists, it means we should pass an ID of this user to a controller to display it in a view. I don't know how. res.send({user.name}) //like this? How should controller receive this? With $http.post? } else { and now if user doesn't exist - we should create it with user ID generated by my function var nUser = new User({ name: generId(), password: req.body.password }); nUser.save(function(err) { if (err) return next(err); )}; )}; )}; Am I doing anything right? I'm pretty new to js and angular. If so - how do I throw a username back at controller? If someone is interested - this service exists for 100+ symbol passphrases so possibility of entering same passphrase as someone else is miserable. And yeah, If someone logged in under 123 password - the other guy will log in as same user if he entered 123 password, but hey, you are warned to make a big passphrase. So I'm confident about the idea and I only need a help with understanding and realization.

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  • jQuery - Save to SQL via PHP

    - by Kenny Bones
    This is probably easy for you guys, but I can't understand it. I want to save the filename of an image to it's own row in the SQL base. Basically, I log on to the site where I have my own userID. And each user has its own column for background images. And the user can choose his own image if he wants to. So basically, when the user clicks on the image he wants, a jquery click event occurs and an ajax call is made to a php file which is supposed to take care of the actual update. The row for each user always exist so there's only an update of the data that's necessary. First, I collect the filename of the css property 'background-image' and split it so I get only the filename. I then store that filename in a variable I call 'filename' which is then passed on to this jQuery snippet: $.ajax({ url: 'save_to_db.php', data: filename, dataType:'Text', type: 'POST', success: function(data) { // Just for testing purposes. alert('Background changed to: ' + data); } }); And this is the php: <?php require("dbconnect.php") ?> <?php $uploadstring = ($_POST['filename']); mysql_query("UPDATE brukere SET brukerBakgrunn = $uploadstring WHERE brukerID=" .$_SESSION['id'] .""; mysql_close(); ?> Basically, each user has their own ID and this is called 'brukerID' The table everything is in is called 'brukere' and the column I'm supposed to update is the one called 'brukerBakgrunn' When I just run the javascript snippet, I get this message box in return where it says: Background changed to: Parse error: syntax error, unexpected ';' in /var/www/clients/client2/web8/web/save_to_db.php on line 8 I actualle get this messagebox twice, not sure why. Line 8 in 'save_to_db.php' is this one: mysql_query("UPDATE brukere SET brukerBakgrunn = $uploadstring WHERE brukerID=" .$_SESSION['id'] .""; Not sure if you need to see db_connect.php as well. I can add that later if you need to see it. So what am I missing here?

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  • Database Schema Versioning Strategies

    - by Jack Ryan
    I work on a project that uses a reasonably large database, the live version weighing in at somewhere around 60-80GB. The live database is the only real definitive source of our schema, and because of its size duplicating this database is too slow to be done often. This means we have ended up developing our database schema in a pretty ad hoc way, using sql compare to migrate changes from dev dbs to the live system, and only wiping our dev dbs every month or two. I am hoping to get some pointers on how to improve our database development work flow so that we have a little more control. Some things to think about: Currently nobody is really in charge of the database schema, all developers can change it if they need to, though generally these decisions are talked about before they are done. There are stored procedures, functions, and views in the database. These should probably be dumped to files so they can be reloaded on every build. Schema changes should probably be checked in as scripts. We have started to do this recently. However all our scripts must then be numbered (because there may be dependencies between them), and must be re runnable (because our build script currently runs them all in order). This makes them hard to read because they are full of conditionals that check whether tables or columns already exist. This is a step that is often forgotten by developers. Getting a new database should be quick and easy. This is currently a big problem, it takes several hours to get a copy of last nights backup and restore it onto a dev machine. Some mechanism needs to be in place to allow developers to update static data. We have tables that contain data that is never updated through the application, but does potentially need to be changed when we do a new release (often this drives dropdowns). The whole thing needs to be runnable as part of a build script. Are there any tools that can be used to help to do this? Eventually I would like to be at a point where a new DB can be built from scratch without copying any data from the live system. I don't mind writing some scripts to glue all the steps together but each part should be easily editable so that we continue to use it rather than make changes directly on DBs.

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  • How to capture child links clicked using jquery?

    - by user244394
    I am trying to capture the event when a child element link is clicked and add class called "highlightchild" to it. Also I want to check if there are any child element link exist or not, if no child element exits ie "third level" highlight with "highlightparent" the parent. How can I do that using jquery? $(document).ready(function() { $('.menu ul').hide(); $('.menu .arrowUp').click(function() { $('.menu ul').hide(); $(this).find(".third-level").toggle(); }); }); html <ul class="menu"> <li class="arrowUp"><a href="#">link1</a> <ul class="third-level" > <!-- third level non-active --> <li class="arrowUp"><a href="/somelink/">Some Link</a></li> </ul> </li> <li class="arrowUp"><a href="#">link2</a> <ul class="third-level" > <!-- third level non-active --> <li class="arrowUp"><a href="/links2/">some Links 2</a></li> </ul> </li> <li class="arrowUp"><a href="#">link3</a> <ul class="third-level" > <!-- third level non-active --> <li class="arrowUp"><a href="/Agri/">Agricultural</a></li> <!-- third level non-active --> <li class="arrowUp"><a href="/sugar/">Sugar</a></li> <!-- third level non-active --> <li class="arrowUp"><a href="/bbc/">Coffee</a></li> <!-- third level non-active --> <li class="arrowUp"><a href="/cnn/">Energy</a></li> <!-- third level non-active --> <li class="arrowUp"><a href="funstuff">Fun stuff</a></li> </ul> </li> <li class="arrowUp"><a href="#">link4</a></li> <li class="arrowUp"><a href="#">link5</a></li> <li class="arrowUp"><a href="#">link6</a></li> </ul>

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  • Correcting a plist with dictionaries

    - by ingenspor
    Plist is copyed to documents directory if it doesn't exist. If it already exists, I want to use the "Name" key from NSDictionary in bundleArray to find the matching NSDictionary in documentsArray. When the match is found, I want to check for changes in the strings and replace them if there is a change. If a match is not found it means this dictionary must be added to documents plist. This is my code: - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { [self managePlist]; return YES; } - (void)managePlist { NSError *error; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *path = [documentsDirectory stringByAppendingPathComponent:@"Objects.plist"]; NSString *bundle = [[NSBundle mainBundle] pathForResource:@"Objects" ofType:@"plist"]; NSFileManager *fileManager = [NSFileManager defaultManager]; if (![fileManager fileExistsAtPath: path]) { [fileManager copyItemAtPath:bundle toPath:path error:&error]; } else { NSArray *bundleArray = [[NSArray alloc] initWithContentsOfFile:bundle]; NSMutableArray *documentArray = [[NSMutableArray alloc] initWithContentsOfFile:path]; BOOL updateDictionary = NO; for(int i=0;i<bundleArray.count;i++) { NSDictionary *bundleDict=[bundleArray objectAtIndex:i]; BOOL matchInDocuments = NO; for(int ii=0;ii<documentArray.count;ii++) { NSMutableDictionary *documentDict = [documentArray objectAtIndex:ii]; NSString *bundleObjectName = [bundleDict valueForKey:@"Name"]; NSString *documentsObjectName = [documentDict valueForKey:@"Name"]; NSRange range = [documentsObjectName rangeOfString:bundleObjectName options:NSCaseInsensitiveSearch]; if (range.location != NSNotFound) { matchInDocuments = YES; } if (matchInDocuments) { if ([bundleDict objectForKey:@"District"] != [documentDict objectForKey:@"District"]) { [documentDict setObject:[bundleDict objectForKey:@"District"] forKey:@"District"]; updateDictionary=YES; } } else { [documentArray addObject:bundleDict]; updateDictionary=YES; } } } if(updateDictionary){ [documentArray writeToFile:path atomically:YES]; } } } If I run my app now I get this message: '-[__NSCFDictionary setObject:forKey:]: mutating method sent to immutable object' How can I fix this? When this is fixed, do you think my code will work? If not, I would be happy for some suggestions on how to do this. I have struggled for a while and really need to publish the update with the corrections! Thanks a lot for your help.

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  • Adding Information in SQLite

    - by Cam
    Hi All, I am having trouble with my Android App when adding information into SQLite. I am relatively new to Java/SQLite and though I have followed a lot of tutorials on SQLite and have been able to get the example code to run I am unable to get tables to be created and data to import when running my own app. I have included my code in two Java files Questions (Main Program) and QuestionData (helper class represents the database). Questions.java: public class Questions extends Activity { private QuestionData questions; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.quiztest); questions = new QuestionData(this); try { Cursor cursor = getQuestions(); showQuestions(cursor); } finally { questions.close(); } } private Cursor getQuestions() { //Select Query String loadQuestions = "SELECT * FROM questionlist"; SQLiteDatabase db = questions.getReadableDatabase(); Cursor cursor = db.rawQuery(loadQuestions, null); startManagingCursor(cursor); return cursor; } private void showQuestions(Cursor cursor) { // Collect String Values from Query and Display them this part of the code is wokring fine when there is data present. QuestionData.java public class QuestionData extends SQLiteOpenHelper { private static final String DATABASE_NAME = "TriviaQuiz.db" ; private static final int DATABASE_VERSION = 2; public QuestionData(Context ctx) { super(ctx, DATABASE_NAME, null, DATABASE_VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE questionlist (_id INTEGER PRIMARY KEY AUTOINCREMENT, QID TEXT, QQuestion TEXT, QAnswer TEXT, QOption1 TEXT, QOption2 TEXT, QOption3 TEXT, QCategoryTagLvl1 TEXT, QCategoryTagLvl2 TEXT, QOptionalTag1 TEXT, QOptionalTag2 TEXT, QOptionalTag3 TEXT, QOptionalTag4 TEXT, QOptionalTag5 TEXT, QTimePeriod TEXT, QDifficultyRating TEXT, QGenderBias TEXT, QAgeBias TEXT, QRegion TEXT, QWikiLink TEXT, QValidationLink1 TEXT, QValidationLink2 TEXT, QHint TEXT, QLastValidation TEXT, QNotes TEXT, QMultimediaType TEXT, QMultimediaLink TEXT, QLastAsked TEXT);"); db.execSQL("INSERT INTO questionlist (_id, QID, QQuestion, QAnswer, QOption1, QOption2, QOption3, QCategoryTagLvl1, QCategoryTagLvl2, QOptionalTag1, QOptionalTag2, QOptionalTag3, QOptionalTag4, QOptionalTag5, QTimePeriod, QDifficultyRating, QGenderBias, QAgeBias, QRegion, QWikiLink, QValidationLink1, QValidationLink2, QHint, QLastValidation, QNotes, QMultimediaType, QMultimediaLink, QLastAsked)"+ "VALUES (null,'Q00001','Example','Ans1','Q1','Q2','Q3','Q4','','','','','','','','','','','','','','','','','','','','')"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); onCreate(db); } } Any suggestions at all would be great. I have tried debugging which suggests that the database does not exist. Thanks in advance for your assistance.

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  • Java template classes using generator or similar?

    - by Hugh Perkins
    Is there some library or generator that I can use to generate multiple templated java classes from a single template? Obviously Java does have a generics implementation itself, but since it uses type-erasure, there are lots of situations where it is less than adequate. For example, if I want to make a self-growing array like this: class EasyArray { T[] backingarray; } (where T is a primitive type), then this isn't possible. This is true for anything which needs an array, for example high-performance templated matrix and vector classes. It should probably be possible to write a code generator which takes a templated class and generates multiple instantiations, for different types, eg for 'double' and 'float' and 'int' and 'String'. Is there something that already exists that does this? Edit: note that using an array of Object is not what I'm looking for, since it's no longer an array of primitives. An array of primitives is very fast, and uses only as much space a sizeof(primitive) * length-of-array. An array of object is an array of pointers/references, that points to Double objects, or similar, which could be scattered all over the place in memory, require garbage collection, allocation, and imply a double-indirection for access. Edit2: good god, voted down for asking for something that probably doesn't currently exist, but is technically possible and feasible? Does that mean that people looking for ways to improve things have already left the java community? Edit3: Here is code to show the difference in performance between primitive and boxed arrays: int N = 10*1000*1000; double[]primArray = new double[N]; for( int i = 0; i < N; i++ ) { primArray[i] = 123.0; } Object[] objArray = new Double[N]; for( int i = 0; i < N; i++ ) { objArray[i] = 123.0; } tic(); primArray = new double[N]; for( int i = 0; i < N; i++ ) { primArray[i] = 123.0; } toc(); tic(); objArray = new Double[N]; for( int i = 0; i < N; i++ ) { objArray[i] = 123.0; } toc(); Results: double[] array: 148 ms Double[] array: 4614 ms Not even close!

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  • Not sure what happens to my apps objects when using NSURLSession in background - what state is my app in?

    - by Avner Barr
    More of a general question - I don't understand the workings of NSURLSession when using it in "background session mode". I will supply some simple contrived example code. I have a database which holds objects - such that portions of this data can be uploaded to a remote server. It is important to know which data/objects were uploaded in order to accurately display information to the user. It is also important to be able to upload to the server in a background task because the app can be killed at any point. for instance a simple profile picture object: @interface ProfilePicture : NSObject @property int userId; @property UIImage *profilePicture; @property BOOL successfullyUploaded; // we want to know if the image was uploaded to out server - this could also be a property that is queryable but lets assume this is attached to this object @end Now Lets say I want to upload the profile picture to a remote server - I could do something like: @implementation ProfilePictureUploader -(void)uploadProfilePicture:(ProfilePicture *)profilePicture completion:(void(^)(BOOL successInUploading))completion { NSUrlSession *uploadImageSession = ..... // code to setup uploading the image - and calling the completion handler; [uploadImageSession resume]; } @end Now somewhere else in my code I want to upload the profile picture - and if it was successful update the UI and the database that this action happened: ProfilePicture *aNewProfilePicture = ...; aNewProfilePicture.profilePicture = aImage; aNewProfilePicture.userId = 123; aNewProfilePicture.successfullyUploaded = NO; // write the change to disk [MyDatabase write:aNewProfilePicture]; // upload the image to the server ProfilePictureUploader *uploader = [ProfilePictureUploader ....]; [uploader uploadProfilePicture:aNewProfilePicture completion:^(BOOL successInUploading) { if (successInUploading) { // persist the change to my db. aNewProfilePicture.successfullyUploaded = YES; [Mydase update:aNewProfilePicture]; // persist the change } }]; Now obviously if my app is running then this "ProfilePicture" object is successfully uploaded and all is well - the database object has its own internal workings with data structures/caches and what not. All callbacks that may exist are maintained and the app state is straightforward. But I'm not clear what happens if the app "dies" at some point during the upload. It seems that any callbacks/notifications are dead. According to the API documentation- the uploading is handled by a separate process. Therefor the upload will continue and my app will be awakened at some point in the future to handle completion. But the object "aNewProfilePicture" is non existant at that point and all callbacks/objects are gone. I don't understand what context exists at this point. How am I supposed to ensure consistency in my DB and UI (For instance update the "successfullyUploaded" property for that user)? Do I need to re-work everything touching the DB or UI to correspond with the new API and work in a context free environment?

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  • Message passing chrome extension

    - by Mayur Kataria
    I wants to create an extension where content script will send message to background page and then on browser action means clicking on extension icon will access that background page and get some data.I am using chrome Version 23.0.1271.64 m on windows8. I am getting following error. Port error: Could not establish connection. Receiving end does not exist. I tried to solve the same. but people are using sendRequest which is not supported by chrome20+. i also found solution mentioned for chrome 20+. But not working. Please help. Below is the file contents. manifest.json { "name": "Test Extension", "version": "1.0", "manifest_version": 2, "description": "A test extension.", "background": "background.html", "content_scripts": [ { "matches": ["<all_urls>"], "js": ["jquery.js","content.js"] } ], "permissions": ["tabs", "http://*/", "https://*/"], "browser_action": { "default_icon": "icon.png", "default_popup": "popup.html" } } background.html <html> <head> <script src="background.js"></script> </head> <body> <h1>Wy</h1> </body> </html> background.js chrome.extension.onMessage.addListener(function(request, sender, sendResponse) { // Chrome 20+ alert(request); console.log('received in listener'); sendResponse({farewell: "goodbye"}); }); content.js $(function(){ console.log('start-sending message'); chrome.extension.sendMessage({greeting: "hello"},function(response){alert(response);}); console.log('end-sending message'); }); popup.html <!doctype html> <html> <head> <title>Getting Started Extension's Popup</title> </style> <!-- JavaScript and HTML must be in separate files for security. --> <script src="jquery.js"></script> <script src="popup.js"></script> </head> <body> </body> </html> popup.js $(function(){ var str_html = "<tr><td width='60%'>S</td><td width='40%'>15</td></tr><tr><td width='60%'>M</td><td width='40%'>25</td></tr>"; $('#sizes_container').html(str_html); var bkg = chrome.extension.getBackgroundPage(); console.log(bkg); });

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  • Big Oh Notation - formal definition.

    - by aloh
    I'm reading a textbook right now for my Java III class. We're reading about Big-Oh and I'm a little confused by its formal definition. Formal Definition: "A function f(n) is of order at most g(n) - that is, f(n) = O(g(n)) - if a positive real number c and positive integer N exist such that f(n) <= c g(n) for all n = N. That is, c g(n) is an upper bound on f(n) when n is sufficiently large." Ok, that makes sense. But hold on, keep reading...the book gave me this example: "In segment 9.14, we said that an algorithm that uses 5n + 3 operations is O(n). We now can show that 5n + 3 = O(n) by using the formal definition of Big Oh. When n = 3, 5n + 3 <= 5n + n = 6n. Thus, if we let f(n) = 5n + 3, g(n) = n, c = 6, N = 3, we have shown that f(n) <= 6 g(n) for n = 3, or 5n + 3 = O(n). That is, if an algorithm requires time directly proportional to 5n + 3, it is O(n)." Ok, this kind of makes sense to me. They're saying that if n = 3 or greater, 5n + 3 takes less time than if n was less than 3 - thus 5n + n = 6n - right? Makes sense, since if n was 2, 5n + 3 = 13 while 6n = 12 but when n is 3 or greater 5n + 3 will always be less than or equal to 6n. Here's where I get confused. They give me another example: Example 2: "Let's show that 4n^2 + 50n - 10 = O(n^2). It is easy to see that: 4n^2 + 50n - 10 <= 4n^2 + 50n for any n. Since 50n <= 50n^2 for n = 50, 4n^2 + 50n - 10 <= 4n^2 + 50n^2 = 54n^2 for n = 50. Thus, with c = 54 and N = 50, we have shown that 4n^2 + 50n - 10 = O(n^2)." This statement doesn't make sense: 50n <= 50n^2 for n = 50. Isn't any n going to make the 50n less than 50n^2? Not just greater than or equal to 50? Why did they even mention that 50n <= 50n^2? What does that have to do with the problem? Also, 4n^2 + 50n - 10 <= 4n^2 + 50n^2 = 54n^2 for n = 50 is going to be true no matter what n is. And how in the world does picking numbers show that f(n) = O(g(n))? Please help me understand! :(

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  • Is this a problem typically solved with IOC?

    - by Dirk
    My current application allows users to define custom web forms through a set of admin screens. it's essentially an EAV type application. As such, I can't hard code HTML or ASP.NET markup to render a given page. Instead, the UI requests an instance of a Form object from the service layer, which in turn constructs one using a several RDMBS tables. Form contains the kind of classes you would expect to see in such a context: Form= IEnumerable<FormSections>=IEnumerable<FormFields> Here's what the service layer looks like: public class MyFormService: IFormService{ public Form OpenForm(int formId){ //construct and return a concrete implementation of Form } } Everything works splendidly (for a while). The UI is none the wiser about what sections/fields exist in a given form: It happily renders the Form object it receives into a functional ASP.NET page. A few weeks later, I get a new requirement from the business: When viewing a non-editable (i.e. read-only) versions of a form, certain field values should be merged together and other contrived/calculated fields should are added. No problem I say. Simply amend my service class so that its methods are more explicit: public class MyFormService: IFormService{ public Form OpenFormForEditing(int formId){ //construct and return a concrete implementation of Form } public Form OpenFormForViewing(int formId){ //construct and a concrete implementation of Form //apply additional transformations to the form } } Again everything works great and balance has been restored to the force. The UI continues to be agnostic as to what is in the Form, and our separation of concerns is achieved. Only a few short weeks later, however, the business puts out a new requirement: in certain scenarios, we should apply only some of the form transformations I referenced above. At this point, it feels like the "explicit method" approach has reached a dead end, unless I want to end up with an explosion of methods (OpenFormViewingScenario1, OpenFormViewingScenario2, etc). Instead, I introduce another level of indirection: public interface IFormViewCreator{ void CreateView(Form form); } public class MyFormService: IFormService{ public Form OpenFormForEditing(int formId){ //construct and return a concrete implementation of Form } public Form OpenFormForViewing(int formId, IFormViewCreator formViewCreator){ //construct a concrete implementation of Form //apply transformations to the dynamic field list return formViewCreator.CreateView(form); } } On the surface, this seems like acceptable approach and yet there is a certain smell. Namely, the UI, which had been living in ignorant bliss about the implementation details of OpenFormForViewing, must possess knowledge of and create an instance of IFormViewCreator. My questions are twofold: Is there a better way to achieve the composability I'm after? (perhaps by using an IoC container or a home rolled factory to create the concrete IFormViewCreator)? Did I fundamentally screw up the abstraction here?

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