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  • UITableViewCell outlets not set during bundle load (possibly very elementary question)

    - by Jan Zich
    What are the most common reasons for an outlet (a class property) not being set during a bundle load? I'm sorry; most likely I'm not using the correct terms. It's my first steps with iPhone OS development and Objective-C, so please bear with me. Here is more details. Basically, I'm trying to create a table view based form with a fixed number of static rows. I followed this example: http://developer.apple.com/iphone/library/documentation/userexperience/conceptual/TableView_iPhone/TableViewCells/TableViewCells.html Scroll down to The Technique for Static Row Content please. I have one nib file with one table view, three table cells and all connections set as in the example. The problem is that the corresponding cell properties in my controller are never initialised. I get an exception in cellForRowAtIndexPath complaining that the returned cell is nil: UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath. Here are the relevant parts from the implementation of the controller: @synthesize cellA; @synthesize cellB; @synthesize cellC; - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 3; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { switch (indexPath.row) { case 0: return cellA; break; case 1: return cellB; break; case 2: return cellC; break; default: return nil; } } And here is the interface part: @interface AssociatePhoneViewController : UITableViewController { UITableViewCell *cellA; UITableViewCell *cellB; UITableViewCell *cellB; } @property (nonatomic, retain) IBOutlet UITableViewCell *cellA; @property (nonatomic, retain) IBOutlet UITableViewCell *cellB; @property (nonatomic, retain) IBOutlet UITableViewCell *cellC; @end This must be possibly one of the the most embarrassing questions on StackOverflow. It looks like the most basic example code. Is is possible that the cells are not instantiated with the nib file? I have them on the same level before the tabula view in the nib file. I tried to move them after the table view, but it did not make any difference. Are table cells in some way special? Do I need to set some flag or some property on them in the nib file? I was under the impression that all classes (views, windows, controllers …) listed in a nib file are simply instantiated (and linked using the provided connections). Could it possibly be some memory issue? The cell properties in my controller are not defined in any special way.

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  • Classes to Entities; Like-class inheritence problems

    - by Stacey
    Beyond work, some friends and I are trying to build a game of sorts; The way we structure some of it works pretty well for a normal object oriented approach, but as most developers will attest this does not always translate itself well into a database persistent approach. This is not the absolute layout of what we have, it is just a sample model given for sake of representation. The whole project is being done in C# 4.0, and we have every intention of using Entity Framework 4.0 (unless Fluent nHibernate can really offer us something we outright cannot do in EF). One of the problems we keep running across is inheriting things in database models. Using the Entity Framework designer, I can draw the same code I have below; but I'm sure it is pretty obvious that it doesn't work like it is expected to. To clarify a little bit; 'Items' have bonuses, which can be of anything. Therefore, every part of the game must derive from something similar so that no matter what is 'changed' it is all at a basic enough level to be hooked into. Sounds fairly simple and straightforward, right? So then, we inherit everything that pertains to the game from 'Unit'. Weights, Measures, Random (think like dice, maybe?), and there will be other such entities. Some of them are similar, but in code they will each react differently. We're having a really big problem with abstracting this kind of thing into a database model. Without 'Enum' support, it is proving difficult to translate into multiple tables that still share a common listing. One solution we've depicted is to use a 'key ring' type approach, where everything that attaches to a character is stored on a 'Ring' with a 'Key', where each Key has a Value that represents a type. This works functionally but we've discovered it becomes very sluggish and performs poorly. We also dislike this approach because it begins to feel as if everything is 'dumped' into one class; which makes management and logical structure difficult to adhere to. I was hoping someone else might have some ideas on what I could do with this problem. It's really driving me up the wall; To summarize; the goal is to build a type (Unit) that can be used as a base type (Table per Type) for generic reference across a relatively global scope, without having to dump everything into a single collection. I can use an Interface to determine actual behavior so that isn't too big of an issue. This is 'roughly' the same idea expressed in the Entity Framework.

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  • XmlHttpRequest bug?

    - by valdo
    Hello all. I'm writing a program that among other things needs to download a file given its URL. I'm too lazy to implement the Http/Https protocols manually, so that I needed some library/object/function that'll do the job. Critical requirement: The download must be asynchronous. That is, the thread that issued the download must be able to do something else "while" downloading the file, plus the download must be able to be aborted anytime without any barbaric side effects (such as internal call to TerminateThread). Nice-to-have requirements: Should be able to download the file "into memory". Means - read the contents of the file as they arrive, not necessarily save it into some "file system" file. It'd be nice to have some convenient Win32 progress notification mechanism (waitable event, semahpore, completion port, etc.), rather than just periodically polling the download status. I've chosen the XmlHttpRequest COM object to do the work. It seemed to work fine enough, plus it supported asynchronous mode. However I noticed that after some period it just stops working. That is, after several successful file downloads it stops downloading anything. I periodically poll it to get its status, it reports "in-progress", but nothing actually happens, and there's no network activity. Moreover, when the same process creates another instance of XmlHttpRequest object to perform new downloads - the effect is the same. The object reports "in progress", whereas it doesn't even try to connect to the server (according to network sniffers and system TCP state). The only way to make this object work back is to restart the process. This makes me suspect that there's a sort of a bug (sorry, I meant undocumented feature) in the object. Also it's not a bug at the level of an individual object, since the problem persists when the object is destroyed and another one is created. It's probably some global state of the DLL that implements this object. Does anyone know something about this? Is this a known bug? I'm pretty sure there's no chance that I have another bug in my code, because of which it seems to me to be the bug is in the XmlHttpRequest. I've done enoughtests and spent time with the debugger to conclude without reasonable doubt that it's just the object stops working. BTW, while the object should work, I do all the waiting via MsgWaitXXXX API calls. So that if this object needs the message loop to work properly (for instance, it may create a hidden notification window and bind it to a socket via WSAAsyncSelect) - I give it the opportunity.

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  • Web Services Primer for a WinForms Developer?

    - by Unicorns
    I've been writing client/server applications with Winforms for about six years now, but I have yet to venture into the web space (neither ASP.NET nor web services). Given the direction that the job market has been heading for some time and the fact that I have a basic curiosity, I'd like to get involved with writing web services, but I don't know where to start. I've read about various options (XML/SOAP vs. JSON, REST vs...well, actually I don't know what it's called, etc.), but I'm not sure what sort of criteria are in play when making the determination to use one or the other. Obviously, I'd like to leverage the tools that I have (Visual Studio, the .NET framework, etc.) without hamstringing myself into only targeting a particular audience (i.e. writing the service in such a way as to make it difficult to consume from a Windows Mobile/Android/iPhone client, for example). For the record, my plan--for now--is to use WCF for my web service development, but I'm open to using another .NET approach if that's advisable. I realize that this question is pretty open-ended so it may get closed, but here are some things I'm wondering: What are some things to consider when choosing the type of web service (REST, etc.) I intend to write? Is it possible (and, if so, feasible) to move from one approach to another? Can web services be written in an event-driven way? As I said I'm a Winforms developer, so I'm used to objects raising events for me to react to. For instance, if I have two clients connected to my service, is there a way for me to "push" information to one of them as a result of an action by the other? If this is possible, is this advisable or am I just not thinking about it correctly? What authentication mechanisms seem to work best for public-facing services? What about if I plan to have different types of OS'es and clients connecting to the service? Is there a generally accepted platform-agnostic approach? In the line of authentication, is this something that I should be doing myself (authenticating an managing sessions, etc.) or is this something should be handled at the framework level and I just define exactly how it should work? If that's the case, how do I tell who the requester has authenticated themselves as? I started writing an authentication mechanism (simple username/password combinations stored in the database and a corresponding session table with a GUID key) within my service and just requiring that key to be passed with every operation (other than logging in, of course), but I want to make sure that I'm not reinventing the wheel here. However, I also don't want to clutter up the server with a bunch of machine user accounts just to use Basic authentication. I'm also under the impression that Digest (and of course Windows) authentication requires a machine (or AD) user account.

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  • R: Plotting a graph with different colors of points based on advanced criteria

    - by balconydoor
    What I would like to do is a plot (using ggplot), where the x axis represent years which have a different colour for the last three years in the plot than the rest. The last three years should also meet a certain criteria and based on this the last three years can either be red or green. The criteria is that the mean of the last three years should be less (making it green) or more (making it red) than the 66%-percentile of the remaining years. So far I have made two different functions calculating the last three year mean: LYM3 <- function (x) { LYM3 <- tail(x,3) mean(LYM3$Data,na.rm=T) } And the 66%-percentile for the remaining: perc66 <- function(x) { percentile <- head(x,-3) quantile(percentile$Data, .66, names=F,na.rm=T) } Here are two sets of data that can be used in the calculations (plots), the first which is an example from my real data where LYM3(df1) < perc66(df1) and the second is just made up data where LYM3 perc66. df1<- data.frame(Year=c(1979:2010), Data=c(347261.87, 145071.29, 110181.93, 183016.71, 210995.67, 205207.33, 103291.78, 247182.10, 152894.45, 170771.50, 206534.55, 287770.86, 223832.43, 297542.86, 267343.54, 475485.47, 224575.08, 147607.81, 171732.38, 126818.10, 165801.08, 136921.58, 136947.63, 83428.05, 144295.87, 68566.23, 59943.05, 49909.08, 52149.11, 117627.75, 132127.79, 130463.80)) df2 <- data.frame(Year=c(1979:2010), Data=c(sample(50,29,replace=T),75,75,75)) Here’s my code for my plot so far: plot <- ggplot(df1, aes(x=Year, y=Data)) + theme_bw() + geom_point(size=3, aes(colour=ifelse(df1$Year<2008, "black",ifelse(LYM3(df1) < perc66(df1),"green","red")))) + geom_line() + scale_x_continuous(breaks=c(1980,1985,1990,1995,2000,2005,2010), limits=c(1978,2011)) plot As you notice it doesn’t really do what I want it to do. The only thing it does seem to do is that it turns the years before 2008 into one level and those after into another one and base the point colour off these two levels. Since I don’t want this year to be stationary either, I made another tiny function: fun3 <- function(x) { df <- subset(x, Year==(max(Year)-2)) df$Year } So the previous code would have the same effect as: geom_point(size=3, aes(colour=ifelse(df1$Year<fun3(df1), "black","red"))) But it still does not care about my colours. Why does it make the years into levels? And how come an ifelse function doesn’t work within another one in this case? How would it be possible to the arguments to do what I like? I realise this might be a bit messy, asking for a lot at the same time, but I hope my description is pretty clear. It would be helpful if someone could at least point me in the right direction. I tried to put the code for the plot into a function as well so I wouldn’t have to change the data frame at all functions within the plot, but I can’t get it to work. Thank you!

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  • many-to-many performance concerns with fluent nhibernate.

    - by Ciel
    I have a situation where I have several many-to-many associations. In the upwards of 12 to 15. Reading around I've seen that it's generally believed that many-to-many associations are not 'typical', yet they are the only way I have been able to create the associations appropriate for my case, so I'm not sure how to optimize any further. Here is my basic scenario. class Page { IList<Tag> Tags { get; set; } IList<Modification> Modifications { get; set; } IList<Aspect> Aspects { get; set; } } This is one of my 'core' classes, and coincidentally one of my core tables. Virtually half of the objects in my code can have an IList<Page>, and some of them have IList<T> where T has its own IList<Page>. As you can see, from an object oriented standpoint, this is not really a problem. But from a database standpoint this begins to introduce a lot of junction tables. So far it has worked fine for me, but I am wondering if anyone has any ideas on how I could improve on this structure. I've spent a long time thinking and in order to achieve the appropriate level of association required, I cannot think of any way to improve it. The only thing I have come up with is to make intermediate classes for each object that has an IList<Page>, but that doesn't really do anything that the HasManyToMany does not already do except introduce another class. It does not extend the functionality and, from what I can tell, it does not improve performance. Any thoughts? I am also concerned about Primary Key limits in this scenario. Most everything needs to be able to have these properties, but the Pages cannot be unique to each object, because they are going to be frequently shared and joined between multiple objects. All relationships are one-sided. (That is, a Page has no knowledge of what owns it). Because of this, I also have no Inverse() mapped HasManyToMany collections. Also, I have read the similar question : Usage of ORMs like NHibernate when there are many associations - performance concerns But it really did not answer my concerns.

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  • ASP.NET MVC : Good Replacement for User Control?

    - by David Lively
    I found user controls to be incredibly useful when working with ASP.NET webforms. By encapsulating the code required for displaying a control with the markup, creation of reusable components was very straightforward and very, very useful. While MVC provides convenient separation of concerns, this seems to break encapsulation (ie, you can add a control without adding or using its supporting code, leading to runtime errors). Having to modify a controller every time I add a control to a view seems to me to integrate concerns, not separate them. I'd rather break the purist MVC ideology than give up the benefits of reusable, packaged controls. I need to be able to include components similar to webforms user controls throughout a site, but not for the entire site, and not at a level that belongs in a master page. These components should have their own code not just markup (to interact with the business layer), and it would be great if the page controller didn't need to know about the control. Since MVC user controls don't have codebehind, I can't see a good way to do this. Update FINALLY, a good (and, in retrospect, obvious) way to accomplish this. using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; namespace K.ObjectModel.Controls { public class TestControl : ViewUserControl { protected override void Render(System.Web.UI.HtmlTextWriter writer) { writer.Write("Hello World"); base.Render(writer); } } } Create a new class which inherits ViewUserControl Override the .Render() method as shown above. Register the control via its associated ASCX as you would in a webForm: <%@ Register TagName="tn" TagPrefix="k" Src="~/Views/Navigation/LeftBar.ascx"%> Use the corresponding tag in whatever view or master page that you need: <k:tn runat="server"/> Make sure your .ascx inherits your new control: <%@ Control Language="C#" Inherits="K.ObjectModel.Controls.TestControl" %> Voila, you're up and running. This is tested with ASP.NET MVC 2, VS 2010 and .NET 4.0. Your custom tag references the ascx partial view, which inherits from the TestControl class. The control then overrides the Render() method, which is called to render the view, giving you complete control over the process from tag to output. Why does everyone try to make this so much harder than it has to be?

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  • Connection hangs after time of inactivity

    - by Sinuhe
    In my application, Spring manages connection pool for database access. Hibernate uses these connections for its queries. At first glance, I have no problems with the pool: it works correctly with concurrent clients and a pool with only one connection. I can execute a lot of queries, so I think that I (or Spring) don't leave open connections. My problem appears after some time of inactivity (sometimes 30 minutes, sometimes more than 2 hours). Then, when Hibernate does some search, it lasts too much. Setting log4j level to TRACE, I get this logs: ... 18:27:01 DEBUG nsactionSynchronizationManager - Retrieved value [org.springframework.orm.hibernate3.SessionHolder@99abd7] for key [org.hibernate.impl.SessionFactoryImpl@7d2897] bound to thread [http-8080-Processor24] 18:27:01 DEBUG HibernateTransactionManager - Found thread-bound Session [org.hibernate.impl.SessionImpl@8878cd] for Hibernate transaction 18:27:01 DEBUG HibernateTransactionManager - Using transaction object [org.springframework.orm.hibernate3.HibernateTransactionManager$HibernateTransactionObject@1b2ffee] 18:27:01 DEBUG HibernateTransactionManager - Creating new transaction with name [com.acjoventut.service.GenericManager.findByExample]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT 18:27:01 DEBUG HibernateTransactionManager - Preparing JDBC Connection of Hibernate Session [org.hibernate.impl.SessionImpl@8878cd] 18:27:01 TRACE SessionImpl - setting flush mode to: AUTO 18:27:01 DEBUG JDBCTransaction - begin 18:27:01 DEBUG ConnectionManager - opening JDBC connection Here it gets frozen for about 2 - 10 minutes. But then continues: 18:30:11 DEBUG JDBCTransaction - current autocommit status: true 18:30:11 DEBUG JDBCTransaction - disabling autocommit 18:30:11 TRACE JDBCContext - after transaction begin 18:30:11 DEBUG HibernateTransactionManager - Exposing Hibernate transaction as JDBC transaction [jdbc:oracle:thin:@212.31.39.50:30998:orcl, UserName=DEVELOP, Oracle JDBC driver] 18:30:11 DEBUG nsactionSynchronizationManager - Bound value [org.springframework.jdbc.datasource.ConnectionHolder@843a9d] for key [org.apache.commons.dbcp.BasicDataSource@7745fd] to thread [http-8080-Processor24] 18:30:11 DEBUG nsactionSynchronizationManager - Initializing transaction synchronization ... After that, it works with no problems, until another period of inactivity. IMHO, it seems like connection pool returns an invalid/closed connection, and when Hibernate realizes that, ask another connection to the pool. I don't know how can I solve this problem or things I can do for delimiting it. Any help achieving this will be appreciate. Thanks. EDIT: Well, it finally was due a firewall rule. Database detects the connection is lost, but pool (dbcp or c3p0) not. So, it tries to query the database with no success. What is still strange for me is that timeout period is very variable. Maybe the rule is specially strange or firewall doesn't work correctly. Anyway, I have no access to that machine and I can only wait for an explanation. :(

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  • How can I have a Makefile automatically rebuild source files that include a modified header file? (I

    - by Nicholas Flynt
    I have the following makefile that I use to build a program (a kernel, actually) that I'm working on. Its from scratch and I'm learning about the process, so its not perfect, but I think its powerful enough at this point for my level of experience writing makefiles. AS = nasm CC = gcc LD = ld TARGET = core BUILD = build SOURCES = source INCLUDE = include ASM = assembly VPATH = $(SOURCES) CFLAGS = -Wall -O -fstrength-reduce -fomit-frame-pointer -finline-functions \ -nostdinc -fno-builtin -I $(INCLUDE) ASFLAGS = -f elf #CFILES = core.c consoleio.c system.c CFILES = $(foreach dir,$(SOURCES),$(notdir $(wildcard $(dir)/*.c))) SFILES = assembly/start.asm SOBJS = $(SFILES:.asm=.o) COBJS = $(CFILES:.c=.o) OBJS = $(SOBJS) $(COBJS) build : $(TARGET).img $(TARGET).img : $(TARGET).elf c:/python26/python.exe concat.py stage1 stage2 pad.bin core.elf floppy.img $(TARGET).elf : $(OBJS) $(LD) -T link.ld -o $@ $^ $(SOBJS) : $(SFILES) $(AS) $(ASFLAGS) $< -o $@ %.o: %.c @echo Compiling $<... $(CC) $(CFLAGS) -c -o $@ $< #Clean Script - Should clear out all .o files everywhere and all that. clean: -del *.img -del *.o -del assembly\*.o -del core.elf My main issue with this makefile is that when I modify a header file that one or more C files include, the C files aren't rebuilt. I can fix this quite easily by having all of my header files be dependencies for all of my C files, but that would effectively cause a complete rebuild of the project any time I changed/added a header file, which would not be very graceful. What I want is for only the C files that include the header file I change to be rebuilt, and for the entire project to be linked again. I can do the linking by causing all header files to be dependencies of the target, but I cannot figure out how to make the C files be invalidated when their included header files are newer. I've heard that GCC has some commands to make this possible (so the makefile can somehow figure out which files need to be rebuilt) but I can't for the life of me find an actual implementation example to look at. Can someone post a solution that will enable this behavior in a makefile? EDIT: I should clarify, I'm familiar with the concept of putting the individual targets in and having each target.o require the header files. That requires me to be editing the makefile every time I include a header file somewhere, which is a bit of a pain. I'm looking for a solution that can derive the header file dependencies on its own, which I'm fairly certain I've seen in other projects.

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  • PostgreSQL triggers and passing parameters

    - by iandouglas
    This is a multi-part question. I have a table similar to this: CREATE TABLE sales_data ( Company character(50), Contract character(50), top_revenue_sum integer, top_revenue_sales integer, last_sale timestamp) ; I'd like to create a trigger for new inserts into this table, something like this: CREATE OR REPLACE FUNCTION add_contract() RETURNS VOID DECLARE myCompany character(50), myContract character(50), BEGIN myCompany = TG_ARGV[0]; myContract = TG_ARGV[1]; IF (TG_OP = 'INSERT') THEN EXECUTE 'CREATE TABLE salesdata_' || $myCompany || '_' || $myContract || ' ( sale_amount integer, updated TIMESTAMP not null, some_data varchar(32), country varchar(2) ) ;' EXECUTE 'CREATE TRIGGER update_sales_data BEFORE INSERT OR DELETE ON salesdata_' || $myCompany || '_' || $myContract || ' FOR EACH ROW EXECUTE update_sales_data( ' || $myCompany || ',' || $myContract || ', revenue);' ; END IF; END; $add_contract$ LANGUAGE plpgsql; CREATE TRIGGER add_contract AFTER INSERT ON sales_data FOR EACH ROW EXECUTE add_contract() ; Basically, every time I insert a new row into sales_data, I want to generate a new table where the name of the table will be defined as something like "salesdata_Company_Contract" So my first question is how can I pass the Company and Contract data to the trigger so it can be passed to the add_contract() stored procedure? From my stored procedure, you'll see that I also want to update the original sales_data table whenever new data is inserted into the salesdata_Company_Contract table. This trigger will do something like this: CREATE OR REPLACE FUNCTION update_sales_data() RETURNS trigger as $update_sales_data$ DECLARE myCompany character(50) NOT NULL, myContract character(50) NOT NULL, myRevenue integer NOT NULL BEGIN myCompany = TG_ARGV[0] ; myContract = TG_ARGV[1] ; myRevenue = TG_ARGV[2] ; IF (TG_OP = 'INSERT') THEN UPDATE sales_data SET top_revenue_sales = top_revenue_sales + 1, top_revenue_sum = top_revenue_sum + $myRevenue, updated = now() WHERE Company = $myCompany AND Contract = $myContract ; ELSIF (TG_OP = 'DELETE') THEN UPDATE sales_data SET top_revenue_sales = top_revenue_sales - 1, top_revenue_sum = top_revenue_sum - $myRevenue, updated = now() WHERE Company = $myCompany AND Contract = $myContract ; END IF; END; $update_sales_data$ LANGUAGE plpgsql; This will, of course, require that I pass several parameters around within these stored procedures and triggers, and I'm not sure (a) if this is even possible, or (b) practical, or (c) best practice and we should just put this logic into our other software instead of asking the database to do this work for us. To keep our table sizes down, as we'll have hundreds of thousands of transactions per day, we've decided to partition our data using the Company and Contract strings as part of the table names themselves so they're all very small in size; file IO for us is faster and we felt we'd get better performance. Thanks for any thoughts or direction. My thinking, now that I've written all of this out, is that maybe we need to write stored procedures where we pass our insert data as parameters, and call that from our other software, and have the stored procedure do the insert into "sales_data" then create the other table. Then, have a second stored procedure to insert new data into the salesdata_Company_Contract tables, where the table name is passed to the stored proc as a parameter, and again have that stored proc do the insert, then update the main sales_data table afterward. What approach would you take?

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  • log4net initialisation

    - by Ruben Bartelink
    I've looked hard for duplicates but have to ask the following, no matter how basic it may seem, to get it clear once and for all! In a fresh Console app using log4net version 1.2.10.0 on VS28KSP1 on 64 bit W7, I have the following code:- using log4net; using log4net.Config; namespace ConsoleApplication1 { class Program { static readonly ILog _log = LogManager.GetLogger(typeof(Program)); static void Main(string[] args) { _log.Info("Ran"); } } } In my app.config, I have: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" /> </configSections> <log4net> <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender"> <file value="Program.log" /> <lockingModel type="log4net.Appender.FileAppender+MinimalLock" /> <appendToFile value="true" /> <rollingStyle value="Size" /> <maxSizeRollBackups value="10" /> <maximumFileSize value="1MB" /> <staticLogFileName value="true" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="[%username] %date [%thread] %-5level %logger [%property{NDC}] - %message%newline" /> </layout> </appender> <root> <level value="DEBUG" /> <appender-ref ref="RollingFileAppender" /> </root> </log4net> </configuration> This doesnt write anything, unless I either add an attribute: [ assembly:XmlConfigurator ] Or explicitly initialise it in Main(): _log.Info("This will not go to the log"); XmlConfigurator.Configure(); _log.Info("Ran"); This raises the following questions: I'm almost certain I've seen it working somewhere on some version of log4net without the addition of the assembly attribute or call in Main. Can someone assure me I'm not imagining that? Can someone please point me to where in the doc it explicitly states that both the config section and the initialisation hook are required - hopefully with an explanation of when this changed, if it did? I can easily imagine why this might be the policy -- having the initialisation step explicit to avoid surprises etc., it's just that I seem to recall this not always being the case... (And normally I have the config in a separate file, which generally takes configsections out of the picture)

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  • Memory Leak with Swing Drag and Drop

    - by tom
    I have a JFrame that accepts top-level drops of files. However after a drop has occurred, references to the frame are held indefinitely inside some Swing internal classes. I believe that disposing of the frame should release all of its resources, so what am I doing wrong? Example import java.awt.datatransfer.DataFlavor; import java.io.File; import java.util.List; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.TransferHandler; public class DnDLeakTester extends JFrame { public static void main(String[] args) { new DnDLeakTester(); //Prevent main from returning or the jvm will exit while (true) { try { Thread.sleep(10000); } catch (InterruptedException e) { } } } public DnDLeakTester() { super("I'm leaky"); add(new JLabel("Drop stuff here")); setTransferHandler(new TransferHandler() { @Override public boolean canImport(final TransferSupport support) { return (support.isDrop() && support .isDataFlavorSupported(DataFlavor.javaFileListFlavor)); } @Override public boolean importData(final TransferSupport support) { if (!canImport(support)) { return false; } try { final List<File> files = (List<File>) support.getTransferable().getTransferData(DataFlavor.javaFileListFlavor); for (final File f : files) { System.out.println(f.getName()); } } catch (Exception e) { e.printStackTrace(); } return true; } }); setDefaultCloseOperation(DISPOSE_ON_CLOSE); pack(); setVisible(true); } } To reproduce, run the code and drop some files on the frame. Close the frame so it's disposed of. To verify the leak I take a heap dump using JConsole and analyse it with the Eclipse Memory Analysis tool. It shows that sun.awt.AppContext is holding a reference to the frame through its hashmap. It looks like TransferSupport is at fault. What am I doing wrong? Should I be asking the DnD support code to clean itself up somehow? I'm running JDK 1.6 update 19.

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  • Reading and writing C++ vector to a file

    - by JB
    For some graphics work I need to read in a large amount of data as quickly as possible and would ideally like to directly read and write the data structures to disk. Basically I have a load of 3d models in various file formats which take too long to load so I want to write them out in their "prepared" format as a cache that will load much faster on subsequent runs of the program. Is it safe to do it like this? My worries are around directly reading into the data of the vector? I've removed error checking, hard coded 4 as the size of the int and so on so that i can give a short working example, I know it's bad code, my question really is if it is safe in c++ to read a whole array of structures directly into a vector like this? I believe it to be so, but c++ has so many traps and undefined behavour when you start going low level and dealing directly with raw memory like this. I realise that number formats and sizes may change across platforms and compilers but this will only even be read and written by the same compiler program to cache data that may be needed on a later run of the same program. #include <fstream> #include <vector> using namespace std; struct Vertex { float x, y, z; }; typedef vector<Vertex> VertexList; int main() { // Create a list for testing VertexList list; Vertex v1 = {1.0f, 2.0f, 3.0f}; list.push_back(v1); Vertex v2 = {2.0f, 100.0f, 3.0f}; list.push_back(v2); Vertex v3 = {3.0f, 200.0f, 3.0f}; list.push_back(v3); Vertex v4 = {4.0f, 300.0f, 3.0f}; list.push_back(v4); // Write out a list to a disk file ofstream os ("data.dat", ios::binary); int size1 = list.size(); os.write((const char*)&size1, 4); os.write((const char*)&list[0], size1 * sizeof(Vertex)); os.close(); // Read it back in VertexList list2; ifstream is("data.dat", ios::binary); int size2; is.read((char*)&size2, 4); list2.resize(size2); // Is it safe to read a whole array of structures directly into the vector? is.read((char*)&list2[0], size2 * sizeof(Vertex)); }

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  • sql statement "into outfile" not working with jdbc

    - by Celeste Berus
    I am attempting to add an "export to CSV" feature to a webapp that displays data from a MySQL database. I have a written a "queryExecuter" class to execute queries from my servlet. I have used this to successfully execute insert queries so I know the connection works etc however queries with the "into outfile" statement are simply not executing. Here is my code, the java class... import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; public class queryExecuter { public void exportToCSV(String query) { DBase db = new DBase(); Connection conn = db.connect( mydatabaseurl ,"myusername","mypassword"); db.exportData(conn,query); } } class DBase { public DBase() { } public Connection connect(String db_connect_str, String db_userid, String db_password) { Connection conn; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); conn = DriverManager.getConnection(db_connect_str, db_userid, db_password); } catch(Exception e) { e.printStackTrace(); conn = null; } return conn; } public void exportData(Connection conn,String query) { Statement stmt; try { stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); stmt.execute(query); } catch(Exception e) { e.printStackTrace(); stmt = null; } } }; The servlet... import java.io.IOException; import java.io.PrintWriter; import java.sql.SQLException; import java.util.logging.Level; import java.util.logging.Logger; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.*; import javax.servlet.http.*; import java.io.*; public class MyExportServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { String query = "select into outfile 'theoutfile.txt' * from mytable;"; request.setAttribute("query", query); queryExecuter mydata = new queryExecuter(); mydata.exportToCSV(query); RequestDispatcher view = request.getRequestDispatcher("ConfirmationPage.jsp"); view.forward(request, response); } } Any help would be greatly appreciated. Thank you

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  • Using XAML + designer to edit Plain Old CLR Objects?

    - by Joe White
    I want to write a POCO in XAML, and use a DataTemplate to display that object in the GUI at runtime. So far, so good; I know how to do all that. Since I'll already have a DataTemplate that can transform my POCO into a WPF visual tree, is there any way to get the Visual Studio designer to play along, and have the Design View show me the POCO+DataTemplate's resulting GUI, as I edit the POCO's XAML? (Obviously the designer wouldn't know how to edit the "design view"; I wouldn't expect the Toolbox or click-and-drag to work on the design surface. That's fine -- I just want to see a preview as I edit.) If you're curious, the POCOs in question would be level maps for a game. (At this point, I'm not planning to ship an end-user map editor, so I'll be doing all the editing myself in Visual Studio.) So the XAML isn't WPF GUI objects like Window and UserControl, but it's still not something where I would want to blindly bang out some XAML and hope for the best. I want to see what I'm doing (the GUI map) as I'm doing it. If I try to make a XAML file whose root is my map object, the designer shows "Intentionally Left Blank - The document root element is not supported by the visual designer." It does this even if I've defined a DataTemplate in App.xaml's <Application.Resources>. But I know the designer can show my POCO, when it's inside a WPF object. One possible way of accomplishing what I want would be to have a ScratchUserControl that just contains a ContentPresenter, and write my POCO XAML inside that ContentPresenter's Content property, e.g.: <UserControl ...> <ContentPresenter> <ContentPresenter.Content> <Maps:Map .../> </ContentPresenter.Content> </ContentPresenter> </UserControl> But then I would have to be sure to copy the content back out into its own file when I was done editing, which seems tedious and error-prone, and I don't like tedious and error-prone. And since I can preview my XAML this way, isn't there some way to do it without the UserControl?

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  • Data Warehouse ETL slow - change primary key in dimension?

    - by Jubbles
    I have a working MySQL data warehouse that is organized as a star schema and I am using Talend Open Studio for Data Integration 5.1 to create the ETL process. I would like this process to run once per day. I have estimated that one of the dimension tables (dimUser) will have approximately 2 million records and 23 columns. I created a small test ETL process in Talend that worked, but given the amount of data that may need to be updated daily, the current performance will not cut it. It takes the ETL process four minutes to UPDATE or INSERT 100 records to dimUser. If I assumed a linear relationship between the count of records and the amount of time to UPDATE or INSERT, then there is no way the ETL can finish in 3-4 hours (my hope), let alone one day. Since I'm unfamiliar with Java, I wrote the ETL as a Python script and ran into the same problem. Although, I did discover that if I did only INSERT, the process went much faster. I am pretty sure that the bottleneck is caused by the UPDATE statements. The primary key in dimUser is an auto-increment integer. My friend suggested that I scrap this primary key and replace it with a multi-field primary key (in my case, 2-3 fields). Before I rip the test data out of my warehouse and change the schema, can anyone provide suggestions or guidelines related to the design of the data warehouse the ETL process how realistic it is to have an ETL process INSERT or UPDATE a few million records each day will my friend's suggestion significantly help If you need any further information, just let me know and I'll post it. UPDATE - additional information: mysql> describe dimUser; Field Type Null Key Default Extra user_key int(10) unsigned NO PRI NULL auto_increment id_A int(10) unsigned NO NULL id_B int(10) unsigned NO NULL field_4 tinyint(4) unsigned NO 0 field_5 varchar(50) YES NULL city varchar(50) YES NULL state varchar(2) YES NULL country varchar(50) YES NULL zip_code varchar(10) NO 99999 field_10 tinyint(1) NO 0 field_11 tinyint(1) NO 0 field_12 tinyint(1) NO 0 field_13 tinyint(1) NO 1 field_14 tinyint(1) NO 0 field_15 tinyint(1) NO 0 field_16 tinyint(1) NO 0 field_17 tinyint(1) NO 1 field_18 tinyint(1) NO 0 field_19 tinyint(1) NO 0 field_20 tinyint(1) NO 0 create_date datetime NO 2012-01-01 00:00:00 last_update datetime NO 2012-01-01 00:00:00 run_id int(10) unsigned NO 999 I used a surrogate key because I had read that it was good practice. Since, from a business perspective, I want to keep aware of potential fraudulent activity (say for 200 days a user is associated with state X and then the next day they are associated with state Y - they could have moved or their account could have been compromised), so that is why geographic data is kept. The field id_B may have a few distinct values of id_A associated with it, but I am interested in knowing distinct (id_A, id_B) tuples. In the context of this information, my friend suggested that something like (id_A, id_B, zip_code) be the primary key. For the large majority of daily ETL processes (80%), I only expect the following fields to be updated for existing records: field_10 - field_14, last_update, and run_id (this field is a foreign key to my etlLog table and is used for ETL auditing purposes).

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  • Gotchas INSERTing into SQLite on Android?

    - by paul.meier
    Hi friends, I'm trying to set up a simple SQLite database in Android, handling the schema via a subclass of SQLiteOpenHelper. However, when I query my tables, the columns I think I've inserted are never present. Namely, in SQLiteOpenHelper's onCreate(SQLiteDatabase db) method, I use db.execSQL() to run CREATE TABLE commands, then have tried both db.execSQL and db.insert() to run INSERT commands on the tables I've just created. This appears to run fine, but when I try to query them I always get 0 rows returned (for debugging, the queries I'm running are simple SELECT * FROM table and checking the Cursor's getCount()). Anybody run into anything like this before? These commands seem to run on command-line sqlite3. Are they're gotchas that I'm missing (e.g. INSERTS must/must not be semicolon terminated, or some issue involving multiple tables)? I've attached some of the code below. Thanks for your time, and let me know if I can clarify further. @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE "+ LEVEL_TABLE +" (" + " "+ _ID +" INTEGER PRIMARY KEY AUTOINCREMENT," + " level TEXT NOT NULL,"+ " rows INTEGER NOT NULL,"+ " cols INTEGER NOT NULL);"); db.execSQL("CREATE TABLE "+ DYNAMICS_TABLE +" (" + " level_id INTEGER NOT NULL," + " row INTEGER NOT NULL,"+ " col INTEGER NOT NULL,"+ " type INTEGER NOT NULL);"); db.execSQL("CREATE TABLE "+ SCORE_TABLE +" (" + " level_id INTEGER NOT NULL," + " score INTEGER NOT NULL,"+ " date_achieved DATE NOT NULL,"+ " name TEXT NOT NULL);"); this.enterFirstLevel(db); } And a sample of the insert code I'm currently using, which gets called in enterFirstLevel() (some values hard-coded just to get it running...): private void insertDynamic(SQLiteDatabase db, int row, int col, int type) { ContentValues values = new ContentValues(); values.put("level_id", "1"); values.put("row", Integer.toString(row)); values.put("col", Integer.toString(col)); values.put("type", Integer.toString(type)); db.insertOrThrow(DYNAMICS_TABLE, "col", values); } Finally, query code looks like this: private Cursor fetchLevelDynamics(int id) { SQLiteDatabase db = this.leveldata.getReadableDatabase(); try { String fetchQuery = "SELECT * FROM " + DYNAMICS_TABLE; String[] queryArgs = new String[0]; Cursor cursor = db.rawQuery(fetchQuery, queryArgs); Activity activity = (Activity) this.context; activity.startManagingCursor(cursor); return cursor; } finally { db.close(); } }

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  • Can this way of storing typed objects be improved?

    - by Pindatjuh
    This is an "can it be improved"-question. Topic: Storing typed objects in memory. Background information: I'm building a compiler for the x86-32 Windows platform for my language. My goal includes typed objects. Idea: Every primitive is a semi-class (it can be used as if it was a normal class, but it's stored more compact). Every class is represented by primitives and some meta-data (containing class-properties, inheritance stuff, etc.). The meta-data is complex: it doesn't use fields but instead context-switches. For primitives, the meta-data is very small, compared to a "real" class, which is alot bigger. This enables another idea that "primitives are objects", in my language, which I found nessecairy. Example: If I have an array of 32 booleans, then the pure content of this array is exactly 4 byte (32 bits of booleans). The meta-data will contain flags that the type is an array of booleans, which contains 32 entries. The meta-data is very compacted, on bit-level: using a sort of "packing" mechanism, which is read by a FSM at runtime, when doing inspection of the type (like when passing the object to methods for checking, etc.) For instance (read from left to right, top to bottom, remember vertical position when going to the right, and check nearest column header for meaning of switch): Primitive? Array? Type-Meta 1 Byte? || Size (1 byte) 1 1 [...] 1 [...] done 0 2 Bytes? || Size (2 bytes) 1 [...] done || Size (4 bytes) 0 [...] done Integer? 1 Byte? 2 Bytes? 0 1 0 1 done 1 done 0 done Boolean? Byte? 0 1 0 done 1 done More-Primitives 0 .... Class-Stuff (Huge) 0 ... (After reaching done the data is inserted. || = byte alignment. [...] is variable sized. ... is not described here, for simplicity. And let's call them cost-based-data-structures.) For an array of 32 booleans containing all true values, the memory for this type would be (read top-down): 1 Primitive 1 Array 1 ArrayType: Primitive 0 Not-Array 0 Not-Integer 1 Boolean 0 Not-Byte (thus bit) 1 Integer Size: 1 Byte 00100000 Array size 01010101 01010101 01010101 01010101 Data (user defined) Thus, 8 bytes represent 32 booleans in an array: 11100101 00100000 01010101 01010101 01010101 01010101 How can I improve this? (Both performance- and memory-consumption wise)

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  • linq to sql with nservicebus table lock issue

    - by IGoor
    I am building a system using NServiceBus and my DataLayer is using Linq 2 SQL. The system is made up of 2 services. Service1 receives messages from NSB. It will query Table1 in my database and inserts a record into Table1 If a certain condition is met a new NSB message is sent to the 2nd service Service2 will update records also in Table1 when it receives messages from Service1 and it does some other non database related work. Service2 is a long running process. The problem I am having is the moment Service2 updates a record in Table1, the table is locked. The lock seems to be in place until Service2 has completed all it is processing. i.e. The lock is not released after my datacontext is disposed. This causes the query in Service1 to timeout. Once Service2 completes processing, Service1 resumes processing again without problem. So for example Service1 code may look like: int x =0; using (DataContext db = new DataContext()) { x = (from dp in db.Table1 select dp).Count(); // this line will timeout while service2 is processing Table1 t = new Table1(); t.Data = "test"; db.Table1.InsertOnSubmit(t); db.SubmitChanges(); } if(x % 50 == 0) CallService2(); The code in service2 may look like: using (DataContext db = new DataContext()) { Table1 t = db.Table1.Where(t => t.id == myId); t.Data = "updated"; db.SubmitChanges(); } // I would have expected the lock to have been released at this point, but this is not the case. DoSomeLongRunningTasks(); // lock will be released once service2 exits I don't understand why the lock is not released when the datacontext is disposed in Service2. To get around the problem I have been calling: db.ExecuteCommand("SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED"); and this works, but I am not happy using it. I want to solve this problem properly. Has any one experienced this sort of problem before and does any one know how to solve it? Why is the lock not released after the datacontext has been disposed? Thanks in advance. p.s. sorry for the extremely long post.

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  • If we don't like it for the presentation layer, then why do we tolerate it for the behavior layer?

    - by greim
    Suppose CSS as we know it had never been invented, and the closest we could get was to do this: <script> // this is the page's stylesheet $(document).ready(function(){ $('.error').css({'color':'red'}); $('a[href]').css({'textDecoration':'none'}); ... }); </script> If this was how we were forced to write code, would we put up with it? Or would every developer on Earth scream at browser vendors until they standardized upon CSS, or at least some kind of declarative style language? Maybe CSS isn't perfect, but hopefully it's obvious how it's better than the find things, do stuff method shown above. So my question is this. We've seen and tasted of the glory of declarative binding with CSS, so why, when it comes to the behavioral/interactive layer, does the entire JavaScript community seem complacent about continuing to use the kludgy procedural method described above? Why for example is this considered by many to be the best possible way to do things: <script> $(document).ready(function(){ $('.widget').append("<a class='button' href='#'>...</div>"); $('a[href]').click(function(){...}); ... }); </script> Why isn't there a massive push to get XBL2.0 or .htc files or some kind of declarative behavior syntax implemented in a standard way across browsers? Is this recognized as a need by other web development professionals? Is there anything on the horizon for HTML5? (Caveats, disclaimers, etc: I realize that it's not a perfect world and that we're playing the hand we've been dealt. My point isn't to criticize the current way of doing things so much as to criticize the complacency that exists about the current way of doing things. Secondly, event delegation, especially at the root level, is a step closer to having a declarative behavior layer. It solves a subset of the problem, but it can't create UI elements, so the overall problem remains.)

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  • OpenVPN (HideMyAss) client on Ubuntu: Route only HTTP traffic

    - by Andersmith
    I want to use HideMyAss VPN (hidemyass.com) on Ubuntu Linux to route only HTTP (ports 80 & 443) traffic to the HideMyAss VPN server, and leave all the other traffic (MySQL, SSH, etc.) alone. I'm running Ubuntu on AWS EC2 instances. The problem is that when I try and run the default HMA script, I suddenly can't SSH into the Ubuntu instance anymore and have to reboot it from the AWS console. I suspect the Ubuntu instance will also have trouble connecting to the RDS MySQL database, but haven't confirmed it. HMA uses OpenVPN like this: sudo openvpn client.cfg The client configuration file (client.cfg) looks like this: ############################################## # Sample client-side OpenVPN 2.0 config file # # for connecting to multi-client server. # # # # This configuration can be used by multiple # # clients, however each client should have # # its own cert and key files. # # # # On Windows, you might want to rename this # # file so it has a .ovpn extension # ############################################## # Specify that we are a client and that we # will be pulling certain config file directives # from the server. client auth-user-pass #management-query-passwords #management-hold # Disable management port for debugging port issues #management 127.0.0.1 13010 ping 5 ping-exit 30 # Use the same setting as you are using on # the server. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. #;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel # if you have more than one. On XP SP2, # you may need to disable the firewall # for the TAP adapter. ;dev-node MyTap # Are we connecting to a TCP or # UDP server? Use the same setting as # on the server. proto tcp ;proto udp # The hostname/IP and port of the server. # You can have multiple remote entries # to load balance between the servers. # All VPN Servers are added at the very end ;remote my-server-2 1194 # Choose a random host from the remote # list for load-balancing. Otherwise # try hosts in the order specified. # We order the hosts according to number of connections. # So no need to randomize the list # remote-random # Keep trying indefinitely to resolve the # host name of the OpenVPN server. Very useful # on machines which are not permanently connected # to the internet such as laptops. resolv-retry infinite # Most clients don't need to bind to # a specific local port number. nobind # Downgrade privileges after initialization (non-Windows only) ;user nobody ;group nobody # Try to preserve some state across restarts. persist-key persist-tun # If you are connecting through an # HTTP proxy to reach the actual OpenVPN # server, put the proxy server/IP and # port number here. See the man page # if your proxy server requires # authentication. ;http-proxy-retry # retry on connection failures ;http-proxy [proxy server] [proxy port #] # Wireless networks often produce a lot # of duplicate packets. Set this flag # to silence duplicate packet warnings. ;mute-replay-warnings # SSL/TLS parms. # See the server config file for more # description. It's best to use # a separate .crt/.key file pair # for each client. A single ca # file can be used for all clients. ca ./keys/ca.crt cert ./keys/hmauser.crt key ./keys/hmauser.key # Verify server certificate by checking # that the certicate has the nsCertType # field set to "server". This is an # important precaution to protect against # a potential attack discussed here: # http://openvpn.net/howto.html#mitm # # To use this feature, you will need to generate # your server certificates with the nsCertType # field set to "server". The build-key-server # script in the easy-rsa folder will do this. ;ns-cert-type server # If a tls-auth key is used on the server # then every client must also have the key. ;tls-auth ta.key 1 # Select a cryptographic cipher. # If the cipher option is used on the server # then you must also specify it here. ;cipher x # Enable compression on the VPN link. # Don't enable this unless it is also # enabled in the server config file. #comp-lzo # Set log file verbosity. verb 3 # Silence repeating messages ;mute 20 # Detect proxy auto matically #auto-proxy # Need this for Vista connection issue route-metric 1 # Get rid of the cached password warning #auth-nocache #show-net-up #dhcp-renew #dhcp-release #route-delay 0 120 # added to prevent MITM attack ns-cert-type server # # Remote servers added dynamically by the master server # DO NOT CHANGE below this line # remote-random remote 173.242.116.200 443 # 0 remote 38.121.77.74 443 # 0 # etc... remote 67.23.177.5 443 # 0 remote 46.19.136.130 443 # 0 remote 173.254.207.2 443 # 0 # END

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  • Objective-C Basic class related question, retaining the value of a specific object using a class fil

    - by von steiner
    Members, scholars, code gurus. My background is far from any computer programming thus my question may seems basic and somewhat trivial to you. Nevertheless it seems that I can't put my head around it. I have googled and searched for the answer, just to get myself confused even more. With that, I would kindly ask for a simple explanation suitable for a non technical person such as myself and for other alike arriving to this thread. I have left a comment with the text "Here is the issue" below, referring to my question. // character.h #import <Foundation/Foundation.h> @interface character : NSObject { NSString *name; int hitPoints; int armorClass; } @property (nonatomic,retain) NSString *name; @property int hitPoints,armorClass; -(void)giveCharacterInfo; @end // character.m #import "character.h" @implementation character @synthesize name,hitPoints,armorClass; -(void)giveCharacterInfo{ NSLog(@"name:%@ HP:%i AC:%i",name,hitPoints,armorClass); } @end // ClassAtLastViewController.h #import <UIKit/UIKit.h> @interface ClassAtLastViewController : UIViewController { } -(void)callAgain; @end // ClassAtLastViewController.m #import "ClassAtLastViewController.h" #import "character.h" @implementation ClassAtLastViewController - (void)viewDidLoad { //[super viewDidLoad]; character *player = [[character alloc]init]; player.name = @"Minsc"; player.hitPoints = 140; player.armorClass = 10; [player giveCharacterInfo]; [player release]; // Up until here, All peachy! [self performSelector:@selector(callAgain) withObject:nil afterDelay:2.0]; } -(void)callAgain{ // Here is the issue, I assume that since I init the player again I loss everything // Q1. I loss all the data I set above, where is it than? // Q2. What is the proper way to implement this character *player = [[character alloc]init]; [player giveCharacterInfo]; } Many thanks in advance, Kindly remember that my background is more related to Salmons breeding than to computer code, try and lower your answer to my level if it's all the same to you.

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  • Do You Really Know Your Programming Languages?

    - by Kristopher Johnson
    I am often amazed at how little some of my colleagues know or care about their craft. Something that constantly frustrates me is that people don't want to learn any more than they need to about the programming languages they use every day. Many programmers seem content to learn some pidgin sub-dialect, and stick with that. If they see a keyword or construct that they aren't familiar with, they'll complain that the code is "tricky." What would you think of a civil engineer who shied away from calculus because it had "all those tricky math symbols?" I'm not suggesting that we all need to become "language lawyers." But if you make your living as a programmer, and claim to be a competent user of language X, then I think at a minimum you should know the following: Do you know the keywords of the language and what they do? What are the valid syntactic forms? How are memory, files, and other operating system resources managed? Where is the official language specification and library reference for the language? The last one is the one that really gets me. Many programmers seem to have no idea that there is a "specification" or "standard" for any particular language. I still talk to people who think that Microsoft invented C++, and that if a program doesn't compile under VC6, it's not a valid C++ program. Programmers these days have it easy when it comes to obtaining specs. Newer languages like C#, Java, Python, Ruby, etc. all have their documentation available for free from the vendors' web sites. Older languages and platforms often have standards controlled by standards bodies that demand payment for specs, but even that shouldn't be a deterrent: the C++ standard is available from ISO for $30 (and why am I the only person I know who has a copy?). Programming is hard enough even when you do know the language. If you don't, I don't see how you have a chance. What do the rest of you think? Am I right, or should we all be content with the typical level of programming language expertise? Update: Several great comments here. Thanks. A couple of people hit on something that I didn't think about: What really irks me is not the lack of knowledge, but the lack of curiosity and willingness to learn. It seems some people don't have any time to hone their craft, but they have plenty of time to write lots of bad code. And I don't expect people to be able to recite a list of keywords or EBNF expressions, but I do expect that when they see some code, they should have some inkling of what it does. Few people have complete knowledge of every dark corner of their language or platform, but everyone should at least know enough that when they see something unfamiliar, they will know how to get whatever additional information they need to understand it.

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  • How To Load Images into Custom UITableViewCell?

    - by Clifton Burt
    This problem is simple, but crucial and urgent. Here's what needs to be done: load 66px x 66px images into the table cells in the MainViewController table. each TableCell has a unique image. But how? Would we use cell.image?... cell.image = [UIImage imageNamed:@"image.png"]; If so, where? Is an if/else statement required? Help? Here's the project code, hosted on Google Code, for easy and quick reference... http://www.google.com/codesearch/p?hl=en#Fcn2OtVUXnY/trunk/apple-sample-code/NavBar/NavBar/MyCustomCell.m&q=MyCustomCell%20lang:objectivec To load each cell's labels, MainViewController uses an NSDictionary and NSLocalizedString like so... //cell one menuList addObject:[NSDictionary dictionaryWithObjectsAndKeys: NSLocalizedString(@"PageOneTitle", @""), kTitleKey, NSLocalizedString(@"PageOneExplain", @""), kExplainKey, nil]]; //cell two menuList addObject:[NSDictionary dictionaryWithObjectsAndKeys: NSLocalizedString(@"PageOneTitle", @""), kTitleKey, NSLocalizedString(@"PageOneExplain", @""), kExplainKey, nil]]; ... // this is where MainViewController loads the cell content - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { MyCustomCell *cell = (MyCustomCell*)[tableView dequeueReusableCellWithIdentifier:kCellIdentifier]; if (cell == nil) { cell = [[[MyCustomCell alloc] initWithFrame:CGRectZero reuseIdentifier:kCellIdentifier] autorelease]; } ... // MyCustomCell.m adds the subviews - (id)initWithFrame:(CGRect)aRect reuseIdentifier:(NSString *)identifier { self = [super initWithFrame:aRect reuseIdentifier:identifier]; if (self) { // you can do this here specifically or at the table level for all cells self.accessoryType = UITableViewCellAccessoryDisclosureIndicator; // Create label views to contain the various pieces of text that make up the cell. // Add these as subviews. nameLabel = [[UILabel alloc] initWithFrame:CGRectZero]; // layoutSubViews will decide the final frame nameLabel.backgroundColor = [UIColor clearColor]; nameLabel.opaque = NO; nameLabel.textColor = [UIColor blackColor]; nameLabel.highlightedTextColor = [UIColor whiteColor]; nameLabel.font = [UIFont boldSystemFontOfSize:18]; [self.contentView addSubview:nameLabel]; explainLabel = [[UILabel alloc] initWithFrame:CGRectZero]; // layoutSubViews will decide the final frame explainLabel.backgroundColor = [UIColor clearColor]; explainLabel.opaque = NO; explainLabel.textColor = [UIColor grayColor]; explainLabel.highlightedTextColor = [UIColor whiteColor]; explainLabel.font = [UIFont systemFontOfSize:14]; [self.contentView addSubview:explainLabel]; //added to mark where the thumbnail image should go imageView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 66, 66)]; [self.contentView addSubview:imageView]; } return self; } HELP?

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  • iphone problem receiving UDP packets

    - by SooDesuNe
    I'm using sendto() and recvfrom() to send some simple packets via UDP over WiFI. I've tried using two phones, and a simulator, the results I'm getting are: Packets sent from phones - recieved by simulator Packets sent from simulator - simulator recvfrom remains blocking. Packets sent from phones - other phone recvfrom remains blocking. I'm not sure how to start debugging this one, since the simulator/mac is able to receive the the packets, but the phones don't appear to be getting the message. A slight aside, do I need to keep my packets below the MTU for my network? Or is fragmentation handled by the OS or some other lower level software? UPDATE: I forgot to include the packet size and structure. I'm transmitting: typedef struct PacketForTransmission { int32_t packetTypeIdentifier; char data[64]; // size to fit my biggest struct } PacketForTransmission; of which the char data[64] is: typedef struct PacketHeader{ uint32_t identifier; uint32_t datatype; } PacketHeader; typedef struct BasePacket{ PacketHeader header; int32_t cardValue; char sendingDeviceID[41]; //dont forget to save room for the NULL terminator! } BasePacket; typedef struct PositionPacket{ BasePacket basePacket; int32_t x; int32_t y; } PositionPacket; sending packet is like: PositionPacket packet; bzero(&packet, sizeof(packet)); //fill packet with it's associated data PacketForTransmission transmissionPacket; transmissionPacket.packetTypeIdentifier = kPositionPacketType; memcpy(&transmissionPacket.data, (void*)&packet, sizeof(packet)); //put the PositionPacket into data[64] size_t sendResult = sendto(_socket, &transmissionPacket, sizeof(transmissionPacket), 0, [address bytes], [address length]); NSLog(@"packet sent of size: %i", sendResult); and recieving packets is like: while(1){ char dataBuffer[8192]; struct sockaddr addr; socklen_t socklen = sizeof(addr); ssize_t len = recvfrom(_socket, dataBuffer, sizeof(dataBuffer), 0, &addr, &socklen); //continues blocking here NSLog(@"packet recieved of length: %i", len); //do some more stuff }

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