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• Using an embedded DB (SQLite / SQL Compact) for Message Passing within an app?

  - by wk1989

  Hello, Just out of curiosity, for applications that have a fairly complicated module tree, would something like sqlite/sql compact edition work well for message passing? So if I have modules containing data such as: \SubsystemA\SubSubSysB\ModuleB\ModuleDataC, \SubSystemB\SubSubSystemC\ModuleA\ModuleDataX Using traditional message passing/routing, you have to go through intermediate modules in order to pass a message to ModuleB to request say ModuleDataC. Instead of doing that, if we we simply store "\SubsystemA\SubSubSysB\ModuleB\ModuleDataC" in a sqlite database, getting that data is as simple as a sql query and needs no routing and passing stuff around. Has anyone done this before? Even if you haven't, do you foresee any issues & performance impact? The only concern I have right now would be the passing of custom types, e.g. if ModuleDataC is a custom data structure or a pointer, I'll need some way of storing the data structure into the DB or storing the pointer into the DB. Thanks, JW EDIT One usage case I haven't thought about is when you want to send a message from ModuleA to ModuleB to get ModuleB to do something rather than just getting/setting data. Is it possible to do this using an embedded DB? I believe callback from the DB would be needed, how feasible is this?

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• 32-bit JVM on 64-bit Windows crashes on launch with -Xmx1300m and plenty of free memory

  - by Konrad Garus

  I'm struggling with Java heap space settings. The default Java on Windows is the 32-bit client regardless of OS version (that's what Oracle recommends to all users). It appears to set max heap size to 256 MB by default, and that is too little for me. I use a custom launcher to start the application. I would like it to use more memory on computers with plenty RAM, and default to -Xmx512m on those with less RAM. As far as I'm aware, the only way is the static -Xmx setting (that has to be set on launch). I have a user who has 8 GB RAM, 64-bit Windows and 32-bit Java 7. Maximum memory visible to the JVM is 4G (as returned by querying OperatingSystemMXBean). I understand why, no issue. For some reason my application is unable to start for this user with -Xmx1300m, even though he has 2.3G free memory. He closed some applications (having 5G free memory), and still it would not launch. The error reported to me was: error occured during init of vm could not reserve enough space for object heap What's going on? Could it be that the 32-bit JVM is only able to address the "first" 4G of memory and has to have a 1300M block available within those first 4 gigabytes? How can I solve this problem, except for asking everyone to install 64-bit Java (what is unlikely to be acceptable)?

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• Force screen size when testing embedded DOS app in Windows 7 command window

  - by tomlogic

  I'm doing some embedded DOS development with OpenWatcom (great Windows-hosted compiler for targeting 16-bit DOS applications). The target hardware has a 24x16 character screen (that supposedly emulates CGA to some degree), and I'm trying to get the CMD.EXE window on my Windows 7 machine to stay at a fixed 24x16 without any scroll bars. I've used both the window properties and MODE CON: COLS=24 LINES=16 to get the screen size that I wanted, but as soon as my application uses an INT10 BIOS calls to clear the screen, the mode jumps back to 80x24. Here's what I'm using to clear the screen: void cls(void) { // Clear screen and reset cursor position to (0,0) union REGS regs; regs.w.cx = 0; // Upper left regs.w.dx = 0x1018; // Lower right (of 16x24) regs.h.bh = 7; // Blank lines attribute (white text on black) regs.w.ax = 0x0600; // 06 = scroll up, AL=00 to clear int86( 0x10, &regs, &regs ); } Any ideas? I can still do my testing at 80x24 (or 80x25), but it doesn't entirely behave like the 24x16 mode.

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• Best ways to construct Dynamic Search Conditions for Sql

  - by CoolBeans

  I have always wondered what's the best way to achieve this task. In most web based applications you have to provide search options on many different criteria. Based on what criteria is chosen behind the scene you modify your SQL. Generally, this is how I tend to go about it:- Have a base SQL template. In the base template have conditions like this WHERE [#PRE_COND1] AND [#PRE_COND2] .. so on and so forth. So an example SQL might look something like SELECT NAME,AGE FROM PERSONS [,#TABLE2] [,#TABLE3] WHERE [#PRE_COND1] AND [#PRE_COND2] ORDER BY [#ORD_COND1] AND [#ORD_COND2] etc. During run time after figuring out the all the search criteria user has entered, I replace the [#PRE_COND1]s and [#ORD_COND1]s with the appropriate SQLs and then execute the query. I personally do not like this brute force method. However, I never came across a better approach either. How do you accomplish such tasks generally given you are either using native JDBC or Spring JDBC? It is almost like I need a C MACRO like functionality in Java to do this.

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• Synthetic click doesn't switch application's menu bar (Mac OS X)

  - by Rok

  Hi. I'm developing some sort of air mouse application for iPhone platform. This applications connects to one computer service which generates mouse events on Mac OS X. I'm generating this events with CGEventCreateMouseEvent() and CGEventPost(). But I've encountered one problem. Let's say you are using Safari and then you click on free desktop space. If you do this with regular mouse it will hide Safari's top menu bar and show Finder menu bar. But on these synthetic events it doesn't act like that. Do I have to post some other event or set some additional properties? Here is my code for mouse up, mouse down: - (void)mouseUp:(int)button { int type = (button == LEFT_BUTTON) ? kCGEventLeftMouseUp : kCGEventRightMouseUp; int mouseButton = (button == LEFT_BUTTON) ? kCGMouseButtonLeft : kCGMouseButtonRight; leftMouseDown = (button == LEFT_BUTTON) ? NO : leftMouseDown; rightMouseDown = (button == RIGHT_BUTTON) ? NO : rightMouseDown; CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateHIDSystemState); CGEventRef event = CGEventCreateMouseEvent (source, type, CGSCurrentInputPointerPosition(), mouseButton); CGEventSetType(event, type); CGEventPost(kCGHIDEventTap, event); CFRelease(event); } - (void)mouseDown:(int)button { int type = (button == LEFT_BUTTON) ? kCGEventLeftMouseDown : kCGEventRightMouseDown; int mouseButton = (button == LEFT_BUTTON) ? kCGMouseButtonLeft : kCGMouseButtonRight; leftMouseDown = (button == LEFT_BUTTON) ? YES : leftMouseDown; rightMouseDown = (button == RIGHT_BUTTON) ? YES : rightMouseDown; CGEventSourceRef source = CGEventSourceCreate(kCGEventSourceStateHIDSystemState); CGEventRef event = CGEventCreateMouseEvent (source, type, CGSCurrentInputPointerPosition(), mouseButton); CGEventSetType(event, type); CGEventPost(kCGHIDEventTap, event); CFRelease(event); }

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• Understanding Security Certificates (and thier pricing)

  - by John Robertson

  I work at a very small company so certificate costs need to be absolutely minimal. However for some applications we do Need to have our customers get that warm fuzzy not-using-a-self-signed certificate feeling. Since creating a "certificate authority" with makecert really just means creating a public/private key pair, it seems pretty clear that creating a public/private key pair FROM such a "certificate authority" really just means generating a second public/private key pair and signing both with the private key that belongs to the "certificate authority". Since the keys are signed anyone can verify they came from the certificate authority I created, or if verisign gave me the pair they sign it with one of their own private keys, and anyone can use verisigns corresponding public key to confirm verisign as the source of the keys. Given this I don't understand when I go to verisign or godaddy why they have rates only for yearly plans, when all I really want from them is a single public/private key pair signed with one of their private keys (so that anyone else can use their public keys to confirm that, yes, they gave me that public/private key pair and they confirmed I was who I said I was so you can trust my public/private key pair as belonging to a legitimate third party). Clearly I am misunderstanding something, what is it? Does verisign retire their public/private key pairs periodically so that my verisign signed key pair "expires" and I need new ones?

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• Expandable columns in a datagrid

  - by Jobe

  Im working on a WPF-applications to present and correct large amounts of data. Im about to implement a datagrid containing data from 3 different sources that are populated from external services. To start with I will only populate the grid with data from one source, the master source. However, sometimes an automated validator will trigger a validation warning or error on one cell and the requirement states that the user should be able to view data from the additional 2 sources in columns next to the selected one. Something like this: Standard view: | col1 src1 | col2 src1 | col3 src1 | | | | | | |faulty | | | | | | User want to show data from source 2 and 3 next to the column "col2 src1" like this: | col1 src1 | col2 src1 | col2 src2 | col2 src3 | col3 src1 | | | | | | | | |corrected | | | | | | | | | | and then be able to correct the faulty formatted cell with data from the other 2 soruces, and then collapse the columns again. I am trying to use the mvvm pattern on this one so I have populated the DataGrid with a ListCollectionView so far. The list contains items with properties like this: MyRowItem {string col1, string col2, string col3} I will then have 2 additional collections with items of type like above but from 2 other sources. I have no idea how to implement this functionality and could use some help on the logics. What approach should I head for?

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• How do software events work internally?

  - by Duddle

  Hello! I am a student of Computer Science and have learned many of the basic concepts of what is going on "under the hood" while a computer program is running. But recently I realized that I do not understand how software events work efficiently. In hardware, this is easy: instead of the processor "busy waiting" to see if something happened, the component sends an interrupt request. But how does this work in, for example, a mouse-over event? My guess is as follows: if the mouse sends a signal ("moved"), the operating system calculates its new position p, then checks what program is being drawn on the screen, tells that program position p, then the program itself checks what object is at p, checks if any event handlers are associated with said object and finally fires them. That sounds terribly inefficient to me, since a tiny mouse movement equates to a lot of cpu context switches (which I learned are relatively expensive). And then there are dozens of background applications that may want to do stuff of their own as well. Where is my intuition failing me? I realize that even "slow" 500MHz processors do 500 million operations per second, but still it seems too much work for such a simple event. Thanks in advance!

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• Android app with library can't find the library.apk

  - by Dean Schulze

  I'm trying to get the FinchVideo example from the Programming Android book to work. It uses the FinchWelcome library. I've set up FinchWelcome as a Library and in the FinchVideo application I have checked the FinchWelcome library in Properties - Android. When I try to run FinchVideo in the emulator it complains that it cannot find FinchWelcome.apk (output below). I'm building for Android 4.0.3. While Googling for this problem I've found that a lot of people have this problem with Android apps that use libraries. No one seems to have found a solution that works consistently, though. None of the Android books I've seen even talk about how to download libraries. What is the proper way to handle libraries in Android applications? Is this a bug in the Eclipse ADT? Thanks. [FinchVideo] Installing FinchVideo.apk... [FinchVideo] Success! [FinchWelcome] Could not find FinchWelcome.apk! [FinchVideo] Starting activity com.oreilly.demo.pa.finchvideo.FinchVideoActivity on device emulator-5554

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• Concept: Information Into Memory Location.

  - by Richeve S. Bebedor

  I am having troubles conceptualizing an algorithm to be used to transform any information or data into a specific appropriate and reasonable memory location in any data structure that I will be devising. To give you an idea, I have a JPanel object instance and I created another Container type object instance of any subtype (note this is in Java because I love this language), then I collected those instances into a data structure not specifically just for those instances but also applicable to any type of object. Now my procedure for fetching those data again is to extract the object specific features similar in category to all object in that data structure and transform it into a integer data memory location (specifically as much as possible) or any type of data that will pertain to this transformation. And I can already access that memory location without further sorting or applications of O(n) time complex algorithms (which I think preferable but I wanted to do my own way XD). The data structure is of any type either binary tree, linked list, arrays or sets (and the like XD). What is important is I don't need to have successive comparing and analysis of data just to locate information in big structures. To give you a technical idea, I have to an array DS that contains JLabel object instance with a specific name "HelloWorld". But array DS contains other types of object (in multitude). Now this JLabel object has a location in the array at index [124324] (which is if you do any type of searching algorithm just to arrive at that location is conceivably slow because added to it the data structure used was an array *note please disregard the efficiency of the data structure to be used I just want to explain to you my concept XD). Now I want to equate "HelloWorld" to 124324 by using a conceptually made function applicable to all data types. So that I can do a direct search by doing this DS[extractLocation("HelloWorld")] just to get that JLabel instance. I know this may sound crazy but I want to test my concept of non-sorting feature extracting search algorithm for any data structure wherein my main problem is how to transform information to be stored into memory location of where it was stored.

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• Does NSClassFromString affect performance?

  - by Tomen

  I want to create a controller that depends on the class of a given instance of a model -(BaseController *)getControllerForModel:(Model *)model { BaseController *controller = nil; Class controllerClass = [BaseController class]; //the default value //find the right controller if ([model isMemberOfClass:[ModelClass1 class]]) controllerClass = [ConcreteController1 class]; else if ([model isMemberOfClass:[ModelClass2 class]]) controllerClass = [ConcreteController2 class]; else if ([model isMemberOfClass:[ModelClass3 class]]) controllerClass = [ConcreteController3 class]; ... else if ([model isMemberOfClass:[ModelClassX class]]) controllerClass = [ConcreteControllerX class]; else Trace(TRACELEVEL_WARNING, @"Unrecognized model type: %@", NSStringFromClass([model class])); //Now instantiate it with the model controller = [[[controllerClass alloc] initWithModel:model] autorelease]; return slotController; } I want to find a more flexible solution to this and thought of having a dictionary, which maps Model-Classes to Controller-Classes and then NSClassFromString could give me the right instance. My question is this: Is NSClassFromString using much of my applications performance if i use it several times (say, 100 times at once)? Or would it be about as fast as the above approach?

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• A question of long-running and disruptive branches

  - by Matt Enright

  We are about to begin prototyping a new application that will share some existing infrastructure assemblies with an existing application, and also involve a significant subset of the existing domain model. Parts of the domain model will likely undergo some serious changes for this new application, and the endgame for all of this, once the new application has been fully specified and is launch-ready is that we would like to re-unify the models of the two applications (as well as share a database, link functionality, etc.), but for the duration of development, prototyping, etc, we will be using a separate database so that we can change things without worrying about impact to development or use of the existing application. Since it is a prototype, there will be a pretty long window during which serious changes or rearchitecturing can occur as product management experiments with different workflows, different customer bases are surveyed, and we try and keep up. We have already made a Subversion branch, so as to not impact concurrent development on the mature application, and are toying with 2 potential ways of moving forward with this: Use the svn branch as the sole mechanism of separation. Make our changes to the existing domain models, and evaluate their impact on the existing application (and make requisite changes to ProjectA) when we have established that our long-running side branch is stable enough for re-entry to trunk. "Fork" the shared code (temporarily): Copy ProjectA.Entities to NewProject.Entities, and treat all of the NewProject code as self-contained. When all of the perturbations around the model have died down and we feel satisfied, manually re-integrate the changes (as granular or sweeping as warranted) back into ProjectA.Entities, updating ProjectA to use the improved models at each step (this can take place either before or after the subversion merge has occurred). The subversion merge will then not handle recombination of any of the heavy changes here. Note: the "fork" method only applies to the code we see significant changes in store for, and whose modification will break ProjectA - shared infrastructure stuff for example, we would just modify in place (on our branch) and let the merge sort out. Development is hard, go shopping. Naturally, after not coming to an agreement, we're turning it over to the oracle of power that is SO. Any experience with any of these methods, pain points to watch out for, something new entirely?

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• is there a signal emiter/consumer engine (like in Django) for .NET (C#)

  - by user118657

  Has .NET (C#) anything like Django's Signals engine? Our business logic become really complicated over few years of adding new features. I'm going to re-architecture it. Currently all features are very coupled that makes regression errors while changing something one one place - some other place may be broken. I really like Django's apps idea where separate applications introduce new functionality and are absolutely separate. Communication between apps is implemented though signals. I wounder if there is something in .NET that allows to divide project business to many separated "apps" (plug-ins, zones, modules, you name it) and make communication using some kind of "signals". For example we have simple order flow. We can add "coupon app" that if exists in the project adds abilities to use discount coupon. We can add "cross sale" module that if exists adds abilities to offer cross-sale products Email notification module that if exists adds abilities to send order email notifications. But in the same time all this modules are "self-contained" means that communication between them is done using emitting signals (ORDER_PROCCESS_START, ORDER_SUCCESS, etcs) and other modules can subscribe to this signals and process them in required way. This architecture is not related to web, all business logic is processed on the server side like without working with HTTP directly. I wonder if it's good architecture from code maintaining and testing point of few, is it possible to do this in .NET? Any drawbacks that I don't realize now?

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• WPF/Silverlight Resources for Businesses

  - by Refracted Paladin

  I am the only developer at a non-profit organization(~200 employees) where we are a M$ shop and 90% of the things I develop are specific to our company and are internal only. I am given a lot of latitude on how I accomplish my goals so using new technologies is in my best interest. So far I have developed all winform & asp.net applications. I would now like to focus on XAML driven development(WPF & Silverlight) and would like your help. I am subscribed to numerous Silverlight blogs and I have went through a few good tutorials however, I would really appreciate a GOOD SOLID book in my hands going forward. I prefer learning books versus reference books and I REALLY would like one from a Business standpoint as well. Shameless, self-promoting is welcomed if you happen to be an author or reviewer for one that meets my criteria. I would, however, prefer that recomendations were based on first-hand experience(no, 'my friend as this awesome book he told me about', please). Though, I don't mind un-released books if say they are an updated version of an existing. If more info is needed to provide accurate recomendations please let me know. Thanks disclaimer -- I know there are an insane amount of Book posts here(SO) but none I believe for my specific need. If there is and I missed it I apologize.

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• C# cross thread dialogue co-operation

  - by John Attridge

  K I am looking at a primarily single thread windows forms application in 3.0. Recently my boss had a progress dialogue added on a separate thread so the user would see some activity when the main thread went away and did some heavy duty work and locked out the GUI. The above works fine unless the user switches applications or minimizes as the progress form sits top most and will not disappear with the main application. This is not so bad if there are lots of little operations as the event structure of the main form catches up with its events when it gets time so minimized and active flags can be checked and thus the dialog thread can hide or show itself accordingly. But if a long running sql operation kicks off then no events fire. I have tried intercepting the WndProc command but this also appears queued when a long running sql operation is executing. I have also tried picking up the processes, finding the current app and checking various memory values isiconic and the like inside the progress thread but until the sql operation finishes none of these get updated. Removing the topmost causes the dialog to disappear when another app activates but if the main app is then brought back it does not appear again. So I need a way to find out if the other thread is minimized or no longer active that does not involve querying the actual thread as that locks until the sql operation finishes. Now I know that this is not the best way to write this and it would be better to have all the heavy processing on separate threads leaving the GUI free but as this is a huge ancient legacy app the time to re-write in that fashion will not be provided so I have to work with what I have got. Any help is appreciated

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• Why is there so much XML in Java these days?

  - by BD at Rivenhill

  This is really more of a philosophy/design issue. I did some work in Java back in the middle 90's and again in the early 2000's and now I'm coming back to it after spending a lot of time in C/C++ and it seems like there was an explosion of XML dependency while I was gone. Major build system tools like ant and maven depend on XML for their configuration, but I'm actually more concerned with all the frameworks, such as Spring, Hibernate, etc. My experience is that powerful supporting libraries like these are where a developer can really get leverage for building programs with lots of features without writing a lot of code, but it really seems like I'm getting one language for the price of two here. I write a bunch of Java classes, but then I also write a bunch of XML files to glue them together. The things that get done in the XML are things that I can see reasonable ways of doing in straight code without the middleman, and they don't really seem to be treated exactly like configuration files: they change rarely and they end up getting committed to source code control like the Java code itself, but they are distributed with the resulting application and need to be unpacked and installed in the classpath in order to get the application to work. I'm working with server applications that are not web-based, so maybe the domain is a bit different from what most people are doing, but I just can't help feeling that I must be doing something wrong here. Can someone point me to a good source of information for why these design choices were made and what problems they are meant to solve so that I can analyze my own experiences in this context?

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• Web services or shared database for (game) server communication?

  - by jaaronfarr

  We have 2 server clusters: the first is made up of typical web applications backed by SQL databases. The second are highly optimized multiplayer game servers which keep all data in memory. Both clusters communicate with clients via HTTP (Ajax with JSON). There are a few cases in which we need to share data between the two server types, for example, reporting back and storing the results of a game (should ultimately end up in the database). We're considering several approaches for inter-server communication: Just share the MySQL databases between clusters (introduce SQL to the game servers) Sharing data in a distributed key-value store like Memcache, Redis, etc. Use an RPC technology like Google ProtoBufs or Apache Thrift Using RESTful web services (the game server would POST back to the web servers, for example) At the moment, we're leaning towards web services or just sharing the database. Sharing the database seems easy, but we're concerned this adds extra memory and a new dependency into the game servers. Web services provide good separation of concerns and fit with the existing Ajax we use, but add complexity, overhead and many more ways for communication to fail. Are there any other good reasons not to use one or the other approach? Which would be easier to scale?

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• Why does my plist file exist even when I've uninstalled an app and wiped the simulator?

  - by just_another_coder

  I am trying to detect the existence of a plist file on application start. When my data class (descendant of NSObject) is initialized, it loads the plist file. Before it loads, it checks to see if the file exists, and if it doesn't, it sets the data = nil instead of trying to process the array of data in the plist file. However, every time it starts it indicates the file exists. Even when I uninstall the app in the organizer and when wiping the simulator directory (iPhone Simulator/3.0/Applications). I have the following static method in a library class named FileIO: +(BOOL) fileExists:(NSString *)fileName { NSString *path = [FileIO getPath:fileName]; // gets the path to the docs directory if ([[NSFileManager defaultManager] fileExistsAtPath:path]) return YES; else return NO; } In my data class: //if( [FileIO fileExists:kFavorites_Filename] ) [FileIO deleteFile:kFavorites_Filename]; if ([FileIO fileExists:kFavorites_Filename]) {NSLog(@"exists"); The "exists" is logged every time unless I un-comment the method to delete the file. How can the file exist if I've deleted the app? I've deleted the simulator directory and uninstalled on the device but both say it still exists. What gives???

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• How to preserve the state of JavaScript closure?

  - by Uccio

  I am working on a migration platform to migrate web applications from a device to another. I am extending it to add the support for preserving JavaScript state. My main task is to create a file representing the current state of the executing application, to transmit it to another device and to reload the state in the destination device. The basic solution I adopted is to navigate the window object and to save all its descendant properties using JSON as base format for exportation and extending it to implement some features: preserving object reference, even if cyclic (dojox.json.ref library) support for timers Date non-numericproperties of arrays reference to DOM elements The most important task I need to solve now is exportation of closures. At this moment I didn't know how to implement this feature. I read about the internal EcmaScript property [[scope]] containing the scope chain of a function, a list-like object composed by all the nested activation context of the function. Unfortunately it is not accessible by JavaScript. Anyone know if there is a way to directly access the [[scope]] property? Or another way to preserve the state of a closure?

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• Creating 1 page PDF of iPad Screen view - How?

  - by user314695

  Hi All, I've asked this question on a couple other forums and have had zero response, so I'm hoping someone here can help point me in the right direction. I have a pretty simple one screen application for my work. It's basically just a recreation of a 1 page paper report that has a company logo, some labels, a few text boxes and a scroll text box for the report. I need to be able to fill out the report then click a button to save it in a graphical form so I can fax, print or email it later. Currently, I'm just programmatically taking a screen capture and saving it to the photo's library (default for screen capture). Then I can just email it from photo's. This works ok, but is kind of hacky, at best. I've read through the new iPad 3.2 guide for creating PDF's (apparently it's supposed to be much easier than before) but I can not get it to work and I've spent countless hours on it now. I'm hoping someone has the answer for me. Alternatively, if anyone knows how I can redirect where the screen capture is stored (default is in the photo album) then maybe I can make that function work. If I could redirect the screen capture to store in my applications document folder, then I can use MFMailCompose to attach it to an email. Lastly, on a side note, does anyone know of a good way to capture a digital signature via touch. For instance, I'd love to have my users be able to just sign their name via touch at the bottom of the document before I convert to PDF or take a screen capture. Thanks in advance for your help. -Ray

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• Limiting object allocation over multiple threads

  - by John

  I have an application which retrieves and caches the results of a clients query. The client then requests different chunks of data and the application sends the relevant results and removes them from the cache. A new requirement for this application is that there needs to be a run-time configurable maximum number of results which may be cached. I've taken the naive approach and implemented this by using a counter under a lock which is incremented every time a result is cached and decremented whenever a result is removed from the cache. Unfortunately, this has drastically reduced the applications performance when processing a large number of concurrent requests. I have tried both a critical section lock and spin-lock; the performance improves a bit with a spin-lock, but is still unacceptably slow. Is there a better way to solve this problem which may improve performance? Right now I have a thread pool that services requests and each request is tied to a Request object which stores that cached results for that particular request. Here is a simplified pseudo code version of my current implementation: void ResultCallback( Result result, Request *request ) { lock totalResultsCached lock cachedLimit if( totalResultsCached + 1 > cachedLimit ) { unlock cachedLimit unlock totalResultsCached //cancel the request return; } ++totalResultsCached; unlock cachedLimit unlock totalResultsCached request.add(result) } void SendResults( int resultsToSend, Request *request ) { while ( resultsToSend > 0 ) { send(request.remove()) lock totalResultsCached --totalResultsCached unlock totalResultsCached --resultsToSend; } }

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• Free cross-platform library to convert numbers (money amounts) to words?

  - by bialix

  I'm looking for cross-platform library which I can use in my C application to convert money amounts (e.g. $123.50) to words (one hundred twenty three dollars and fifty cents). I need support for multiple currencies: dollars, euros, UK pounds etc. Although I understand this is not hard at all to write my own implementation, but I'd like to avoid reinventing wheel. I've tried to google it, but there is too much noise related to MS Word converters. Can anybody suggest something? UPDATE numerous comments suggest to write my own implementation because it's really easy task. And I agree. My point was about support of multiple currencies in the same time and different business rules to spell the amounts (should be fractional part written as text or numbers? etc.) As I understand serious business applications have such library inside, but I think there is nothing open-source available, maybe because it seems as very easy task. I'm going to write my own libary and then open-source it. Thanks to all.

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• Are workflows good for web service business logic?

  - by JL

  I have a series of complex web services that are getting used in my SOA application. I am generally happy with the overall design of the application, but as the complexity grows, I was wondering if Windows Workflow might be the way to go. My motivations for this are that you can get a graphic representation of the applications functionality, so it would be easier to maintain the code by its business function, rather than what I have now ( a standard 3 tier class library structure). My concerns are: I would be inducing an abstraction in my code, and I don't want to spend time having to deal with possible WF quirks or bugs. I've never worked with WF, is it a solid technology? I don't want to hit any WF limitations that prevent me from developing my solution. Is a WF even the right solution for the task? Simply put I am considering writing my next web service in this app to call a WF, and in this work flow manage the tasks the web service needs to carry out. I think it will be much neater and easier to maintain than a regular c# class library (maintainable by namespaces, classes ). Do you think this is the right thing to do? I'm hoping for positive feedback on WF (.net 4), but brutal honestly at the end of the day would help more. Thanks

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• Reference remotely located assembly (web uri) from locally installed application?

  - by moonground.de

  Hi Stackoverflowers! :) We have a .NET application for Windows which is installed locally by Microsoft Installer. Now we have the need to use additional assemblies which are located online at our Web Servers. We'd like to refer to a remote uri like https://www.ourserver.com/OurProductName/ExternalLib.dll and reveal additional functionality, which is described roughly by a known common ("AddIn/Plugin") Interface. These are not 3rd Party Plugins, we just want be able to exchange parts of the application frequently, without the need to have frequent software updates. Our first idea was to add some kind of "remote refence" in Visual Studio by setting the path to the remote assembly uri. But Visual Studio downloaded the assembly immediately to a temporary directory, adding a reference to it. Our second attempt then, is simply using a WebRequest (or WebClient) to retrieve a binary stream of the Assembly, loading it "from image" by using Assembly.Load(...). This actually works, but is not very elegant and requires more additional programming for verification etc. We hoped Clickonce would provide useful techniques but apparently it's suitable for standalone applications only. (Correct me?) Is there a way (.net native or by framework/api) to reference remotely located assemblies? Thanks in advance and have a happy easter!

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• Do I need a spatial index in my database?

  - by Sanoj

  I am designing an application that needs to save geometric shapes in a database. I haven't choosen the database management system yet. In my application, all database queries will have an bounding box as input, and as output I want all shapes within that database. I know that databases with a spatial index is used for this kind of application. But in my application there will not be any queries of type "give me objects nearby x/y" or other more complex queries that are useful in a GIS application. I am planning of having a database without a spatial index and have queries looking like: SELECT * FROM shapes WHERE x < max_x AND x > min_x AND y < max_y AND y > min_y And have an index on the columns x (double) and y (double). As long I can see, I don't really need a database with an spatial index, howsoever my application is close to that kind of applications. And even if I would like to have nearby queries, then I could create a big enough bounding box around that point. Or will this lead to poor performance? Do I really need a spatial database? And when is a spatial index needed?

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