What's the point of this in objective-c
- by Mk12
SomeObject *temp = [[SomeObject alloc] init]
self.theObject = temp;
[temp release];
Why is it always done that way? Why not
self.theObject = [[SomeObject alloc] init];
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How to create skype like message window?
- by Miraaj
Hi all, I am just trying to design skype like message window , for this I have taken the NSDrawer element. It contains : a table view on left, menu items on top, text field on right bottom and text view at central portion on right side. Using text view I can play with string being displayed but I cannot draw the line between messages or round rectangle surrounding user name and time stamp. Can anyone suggest me how can I achieve same look and feel for central message view as in skype?? or is there any better control then NSTextView to be used for it?? Thanks, for any suggestion... MiraajRead the article
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How do I dynamically name objects in Java?
- by hatboysam
Let's say I needed to make a series of String[] objects. I know that if i wanted to make a string array called "test" to hold 3 Strings I could do String[] test = new String[3]; But let's say I needed to make a series of these arrays and I wanted them to be named, 1,2, 3, 4, 5... etc. For however many I needed and I didn't know how many I'd need. How do I achieve a similar effect to this: for (int k=0; k=5; k++){ String[] k = new String[3]; } Which would created 5 string arrays named 1 through 5. Basically I want to be able to create array objects with a name detemined by some other function. Why can't I seem to do this? Am I just being stupid?Read the article
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Overwriting arguments object for a Javascript function
- by Ian Storm Taylor
If I have the following: // Clean input. $.each(arguments, function(index, value) { arguments[index] = value.replace(/[\W\s]+/g, '').toLowerCase(); }); Would that be a bad thing to do? I have no further use for the uncleaned arguments in the function, and it would be nice not to create a useless copy of arguments just to use them, but are there any negative effects to doing this? Ideally I would have done this, but I'm guessing this runs into problems since arguments isn't really an Array: arguments = $.map(arguments, function(value) { return value.replace(/[\W\s]+/g, '').toLowerCase(); }); Thanks for any input. EDIT: I've just realized that both of these are now inside their own functions, so the arguments object has changed. Any way to do this without creating an unnecessary variable?Read the article
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Database layout tagging system
- by Kurresmack
I am creating a web site for a customer and they want to be able to create articles. My idea is to tag them so I am going to implement the system. What is the best design, both from an architectural and a perfomance perspective: 1. To have table with all tags and then have a one to many relationship table that links a tag like this: articles table with ID tags table with ID one to many table with columns Article.ID and Tags.ID 2. To have one table with articles and one with tags for articles like this: articles table with ID tags table with Article.ID and tag text Thanks in advance!Read the article
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How can I share Configuration Settings across multiple projects in Visual Studio?
- by Muneeb
Ok I know this may be a design issue, so I would love to have remarks on that as well. I have a Visual Studio web application solution. I have three projects as UserInterface, BusinessLogic and DataAccess. I had to store some user defined settings and I created configSections in the config file. I access these configSections through classes which inherit from .NET's ConfigurationSection base class. So in short for every project I had a separate configSection and for that corresponding configSection I had a class in that project inheriting from ConfigurationSection to access the config section settings. This works all sweet. But the problem arises if there is any setting which I need to use across multiple projects. So If I need to use a setting defined in UserInterface project configSection in, let say, BusinessLogic project I have to actually make a copy of that setting in the BusinessLogic's configSection. This ends up having the same setting copied across multiple configSections. Isn't this a bit too redundant?Read the article
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Is this call to a function object inlined?
- by dehmann
In the following code, Foo::add calls a function via a function object: struct Plus { inline int operator()(int x, int y) const { return x + y; } }; template<class Fct> struct Foo { Fct fct; Foo(Fct f) : fct(f) {} inline int add(int x, int y) { return fct(x,y); // same efficiency adding directly? } }; Is this the same efficiency as calling x+y directly in Foo::add? In other words, does the compiler typically directly replace fct(x,y) with the actual call, inlining the code, when compiling with optimizations enabled?Read the article
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What is the difference between MVC model 1 and model 2?
- by Alex Ciminian
I've recently discovered that MVC is supposed to have two different flavors, model one and model two. I'm supposed to give a presentation on MVC1 and I was instructed that "it's not the web based version, that is refered to as MVC2". As the presentations are about design patterns in general, I doubt that this separation is related to Java (I found some info on Sun's site, but it seemed far off) or ASP. I have a pretty good understanding of what MVC is and I've used several (web) frameworks that enforce it, but this terminology is new to me. How is the web-based version different from other MVC (I'm guessing GUI) implementations? Does it have something to do with the stateless nature of HTTP? Thanks, AlexRead the article
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Microsoft JScript runtime error: Object required
- by Nani
I wrote a simple javascript function for validating to fields in a aspx page function validate() { if (document.getElementById("<%=tbName.ClientID%>").value=="") { alert("Name Feild can not be blank"); document.getElementById("<%=tbName.ClientID%>").focus(); return false; } if (document.getElementById("<%=ddlBranch.ClientID%>").value=="SelectBranch") { alert("Branch Should Be Selected"); document.getElementById("<%=ddlBranch.ClientID%>").focus(); return false; } } Everything worked fine. Later I linked it to aspx page like a external js file. Now its giving error "Microsoft JScript runtime error: Object required". I'm unable to know where I went wrong.Read the article
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What ORMs work well with Scala?
- by Clinton R. Nixon
I'm about to write a Scala command-line application that relies on a MySQL database. I've been looking around for ORMs, and am having trouble finding one that will work well. The Lift ORM looks nice, but I'm not sure it can be decoupled from the entire Lift web framework. ActiveObjects also looks OK, but the author says that it may not work well with Scala. I'm not coming to Scala from Java, so I don't know all the options. Has anyone used an ORM with Scala, and if so, what did you use and how well did it work?Read the article
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javascript: execute a bunch of asynchronous method with one callback
- by Samuel Michelot
I need to execute a bunch of asynchronous methods (client SQLite database), and call only one final callback. Of course, the ugly way is: execAll : function(callBack) { asynch1(function() { asynch2(function() { ... asynchN(function() { callBack(); }) }) }); } But I know there are better ways to do it. Intuitively I would detect when all call back has been called with a counter to call the final callback. I think this is a common design-pattern, so if someone could point me in the right direction... Thanks in advance !Read the article
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C++ smart pointer for non-object type?
- by Brian
Hi, I'm trying to use smart pointers such as auto_ptr, shared_ptr. However, I don't know how to use it in this situation. CvMemStorage *storage = cvCreateMemStorage(); ... use the pointer ... cvReleaseMemStorage(&storage); I'm not sure, but I think that the storage variable is just malloc'ed memory, not object. Is there a way to use the smart pointers for the storage variable? Thank you.Read the article
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Lackadaisical One-to-One between Char and Byte Streams
- by Vaibhav Bajpai
I expected to have a one-to-one correspondence between the character streams and byte streams in terms of how the classes are organized in their hierarchy. FilterReader and FilterWriter (character streams) correspond back to FilterInputStream and FilterOutputStream (byte stream) classes. However I noticed few changes as - BufferedInputStream extends FilterInputStream, but BufferedReader does NOT extend FilterReader. BufferedOutputStream and PrintStream both extend FilterOutputStream, but BufferedWriter and PrintWriter does NOT extend FilterWriter. FilterInputStream and FilterOutputStream are not abstract classes, but FilterReader and FilterWriter are. I am not sure if I am being too paranoid to point out such differences, but was just curious to know if there was design reasoning behind such decision.Read the article
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T-SQL error object exists when separated in if/else blocks
- by Jeff O
I get the error: Msg 2714, Level 16, State 1, Line 16 There is already an object named '#mytemptable' in the database. There are ways around it, but wonder why this happens. Seems like SQL Server is verifying both blocks of the if/else statement? declare @choice int select @choice = 1 if @choice = 1 begin select 'MyValue = 1' AS Pick into #my_temp_table end else begin select 'MyValue <> 1' AS Pick into #my_temp_table end select * from #temptable drop table #temptable If the tables have different names, it works. Or if I create the temp table and use Insert Into... statements that works as well.Read the article
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get next/previous month from a Time object
- by tcurdt
I have a Time object and would like to find the next/previous month. Adding subtracting days does not work as the days per month vary. time = Time.parse('21-12-2008 10:51 UTC') next_month = time + 31 * 24 * 60 * 60 Incrementing the month also falls down as one would have to take care of the rolling time = Time.parse('21-12-2008 10:51 UTC') next_month = Time.utc(time.year, time.month+1) time = Time.parse('01-12-2008 10:51 UTC') previous_month = Time.utc(time.year, time.month-1) The only thing I found working was time = Time.parse('21-12-2008 10:51 UTC') d = Date.new(time.year, time.month, time.day) d >>= 1 next_month = Time.utc(d.year, d.month, d.day, time.hour, time.min, time.sec, time.usec) Is there a more elegant way of doing this that I am not seeing? How would you do it?Read the article
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What is "sentry object" in C++?
- by Romain Hippeau
I answered this question, and Potatoswatter answered too as The modern C++ equivalent would be a sentry object: construct it at the beginning of a function, with its constructor implementing call(), and upon return (or abnormal exit), its destructor implements I am not familiar with using sentry objects in C++. I thought they were limited to input and output streams. Could somebody explain to me about C++ sentry objects as well as how to use them as an around interceptor for one or more methods in a class ? i.e. How to do this ? Sentry objects are very similar indeed. On the one hand they require explicit instantiation (and being passed this) but on the other hand you can add to them so that they check not only the invariants of the class but some pre/post conditions for the function at hand.Read the article
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Factor Clojure code setting many different fields in a Java object
- by chris
How do I factor code setting many different fields in a Java object? I would like to factor (set! (. employee name) "Chris") (set! (. employee age) 100) (set! (. employee salary) 5000) to (doseq [field '((name "Chris") (age 100) (salary 5000))] (set! (. employee (first field)) (second field))) However this won't work because the period is a macro, and tries to evaluate (first field) literally. By the way, I understand that setting fields is not good practice. I need to inter-operate with legacy code.Read the article
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Rails + Dragonfly gem: Saving image in a directory structure based on ActiveRecord object attributes
- by Allen Bargi
I'm using dragonfly gem to manage images and attachments in my rails app and I need to store images in a specific directory structure based on my user model. let' say I have user model which has a name and each user has many albums, which have a name also, then I want the images to be stored in "#{RAILS_ROOT}/public/system/#{user.name}/#{user.album.name}/#{suffix}" I've managed to changed the root_path in dragon fly and I even overrided relative_storage_path like this: class MyDataStore < Dragonfly::DataStorage::FileDataStore private def relative_storage_path(suffix) "#{suffix}" end end but still, I don't know how I can pass the ActiveRecord object attributes like user.name and user.album.name to relative_storage_path to create my ideal path. do you have any idea how I can do such a thing?Read the article
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Application Composer Series: Where and When to use Groovy
- by Richard Bingham
This brief post is really intended as more of a reference than an article. The table below highlights two things, firstly where you can add you own custom logic via groovy code (end column), and secondly (middle column) when you might use each particular feature. Obviously this applies only where Application Composer exists, namely Fusion CRM and Oracle Sales Cloud, and is based on current (release 8) functionality. Feature Most Common Use Case Groovy Field Triggers React to run-time data changes. Only fired when the field is changed and upon submit. Y Object Triggers To extend the standard processing logic for an object, based on record creation, updates and deletes. There is a split between these firing events, with some related to UI/ADF actions and others originating in the database. UI Trigger Points: After Create - fires when a new object record is created. Commonly used to set default values for fields. Before Modify - Fires when the end-user tries to modify a field value. Could be used for generic warnings or extra security logic. Before Invalidate - Fires on the parent object when one of its child object records is created, updated, or deleted. For building in relationship logic. Before Remove - Fires when an attempt is made to delete an object record. Can be used to create conditions that prevent deletes. Database Trigger Points: Before Insert in Database - Fires before a new object is inserted into the database. Can be used to ensure a dependent record exists or check for duplicates. After Insert in Database - Fires after a new object is inserted into the database. Could be used to create a complementary record. Before Update in Database -Fires before an existing object is modified in the database. Could be used to check dependent record values. After Update in Database - Fires after an existing object is modified in the database. Could be used to update a complementary record. Before Delete in Database - Fires before an existing object is deleted from the database. Could be used to check dependent record values. After Delete in Database - Fires after an existing object is deleted from the database. Could be used to remove dependent records. After Commit in Database - Fires after the change pending for the current object (insert, update, delete) is made permanent in the current transaction. Could be used when committed data that has passed all validation is required. After Changes Posted to Database - Fires after all changes have been posted to the database, but before they are permanently committed. Could be used to make additional changes that will be saved as part of the current transaction. Y Field Validation Displays a user entered error message based groovy logic validating the field value. The message is shown only when the validation logic returns false, and the logic is triggered only when tabbing out of the field on the user interface. Y Object Validation Commonly used where validation is needed across multiple related fields on the object. Triggered on the submit UI action. Y Object Workflows All Object Workflows are fired upon either record creation or update, along with the option of adding a custom groovy firing condition. Y Field Updates - change another field when a specified one changes. Intended as an easy way to set different run-time values (e.g. pick values for LOV's) plus the value field permits groovy logic entry. Y E-Mail Notification - sends an email notification to specified users/roles. Templates support using run-time value tokens and rich text. N Task Creation - for adding standard tasks for use in the worklist functionality. N Outbound Message - will create and send an XML payload of the related object SDO to a specified endpoint. N Business Process Flow - intended for approval using the seeded process, however can also trigger custom BPMN flows. N Global Functions Utility functions that can be called from any groovy code in Application Composer (across applications). Y Object Functions Utility functions that are local to the parent object. Usually triggered from within 'Buttons and Actions' definitions in Application Composer, although can be called from other code for that object (e.g. from a trigger). Y Add Custom Fields When adding custom fields there are a few places you can include groovy logic. Y Default Value - to add logic within setting the default value when new records are entered. Y Conditionally Updateable - to add logic to set the field to read-only or not. Y Conditionally Required - to add logic to set the field to required or not. Y Formula Field - Used to provide a new aggregate field that is entirely based on groovy logic and other field values. Y Simplified UI Layouts - Advanced Expressions Used for creating dynamic layouts for simplified UI pages where fields and regions show/hide based on run-time context values and logic. Also includes support for the depends-on feature as a trigger. Y Related References This Blog: Application Composer Series Extending Sales Guide: Using Groovy Scripts Groovy Scripting Reference GuideRead the article
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What can map database tables like LINQ to SQL did?
- by trnTash
A good thing in LINQ to SQL was a fast and reliable way to map database tables and convert them into classes accessible from c# project. However it is no longer recommended to create projects using LINQ to SQL. What is its substitute? What kind of tool should I use in VS 2010 today if I want to have the same functionality as I had with LINQ to SQL?Read the article
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Surrogate key for date dimension?
- by Navin
There are 2 school of thoughts : Use surrogate key preferbly in the format of YYYYMMDD as this will always be sequential. Eliminate Date dimension surrogate key and use actual date instead. My Questions to experts on dimension modeling are : 1> Which design would you prefer and why ? 2> How should we handle unknown values in each of the cases, Can we simply place NULL in Fact table for unknown dates as Foreign Key can be NULL (if no why)? 3> If we need to partition fact table on date column ,how would we achieve that in case 1. I am inclined towards using actual date and using NULL to represent UNKNOWN dates in fact table , as date related validation on fact can be done without need to look in to dimension table.Read the article
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C# how to calculate hashcode from an object reference.
- by Wayne
Folks, here's a thorny problem for you! A part of the TickZoom system must collect instances of every type of object into a Dictionary< type. It is imperative that their equality and hash code be based on the instance of the object which means reference equality instead of value equality. The challenge is that some of the objects in the system have overridden Equals() and GetHashCode() for use as value equality and their internal values will change over time. That means that their Equals and GetHashCode are useless. How to solve this generically rather than intrusively? So far, We created a struct to wrap each object called ObjectHandle for hashing into the Dictionary. As you see below we implemented Equals() but the problem of how to calculate a hash code remains. public struct ObjectHandle : IEquatable<ObjectHandle>{ public object Object; public bool Equals(ObjectHandle other) { return object.ReferenceEquals(this.Object,other.Object); } } See? There is the method object.ReferenceEquals() which will compare reference equality without regard for any overridden Equals() implementation in the object. Now, how to calculate a matching GetHashCode() by only considering the reference without concern for any overridden GetHashCode() method? Ahh, I hope this give you an interesting puzzle. We're stuck over here. Sincerely, WayneRead the article
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Is there such a thing as too many tables?
- by Stacey
I've been searching stackoverflow for about an hour now and couldn't find any topics related, so I apologize if this is a duplicate question. My inquery is this. Is there a point at which there are too many tables in a database? Even if the structure is well organized, thought out, and perfectly facilitates the design intent? I have a database that is quickly approaching 40 tables - about 10 main ones, and over 30 ancillary tables (junction tables, 'enumeration' tables, etc). Am I just a bad developer - or should I be trying something different? It seems like so many to me, I'm really afraid at how it will impact the performance of the project. I have done a lot of condensing where possible, grouped similar things where possible, etc. The database is built in MS-SQL 2008.Read the article
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Is there a standard practice for storing default application data?
- by Rox Wen
Our application includes a default set of data. The default data includes coefficients and other factors that are unlikely to ever change but still need to be update-able by the user. Currently, the original default data is stored as a populated class within the application. Data updates are stored to an external XML file. This design allows us to include a "reset" feature to restore the original default data. Our rationale for not storing defaults externally [e.g. XML file] was to minimize the risk of being altered. The overall volume of data doesn't warrant a database. Is there a standard practice for storing "default" application data?Read the article
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One executable with cmd-line params or just many satellite executables?
- by Nikos Baxevanis
I design an application back-end. For now, it is a .NET process (a Console Application) which hosts various communication frameworks such as Agatha and NServiceBus. I need to periodically update my datastore with values (coming from the application while it's running). I found three possible ways: Accept command line arguments, so I can call my console app with -update. On start up a background thread will periodically invoke the update method. Create an updater.exe app which will do the updates, but I will have code duplication since in some way it will need to query the data from the source in order to save it to the datastore. Which one is better?Read the article
