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  • Delphi Unit local variables - how to make each instance unique?

    - by Justin
    Ok, this, I'm sure is something simple that is easy to do. The problem : I've inherited scary spaghetti code and am slowly trying to better it when new features need adding - generally when a refactor makes adding the new feature neater. I've got a bunch of code I'm packing into a single unit which, in different places in the application, controls the same physical thing in the outside world. The control appears in several places in the application and operates slightly differently in each instance. What I've done is to create a unit with all of the features I need which I can simply drop, as a frame, into each form that requires it. Each form then uses the unit's interface methods to customise the behaviour for each instance. The problem within the problem : In the unit in question (the frame) I have a variable declared in the IMPLEMENTATION section - local to the unit. I also have a procedure, declared in the TYPE section which takes an argument and assigns that argument to the local variable in question - each form passes a unique variable to each instance of the frame/unit. What I want it to do is for each instance of the frame to keep its own version of that variable, different from the others, and use that to define how it operates. What seems to be happening, however, is that all instances are using the same value, even if I explicitly pass each instance a different variable. ie: Unit FlexibleUnit; interface uses //the uses stuff type TFlexibleUnit=class(TFrame) //declarations including procedure makeThisInstanceX(passMeTheVar:integer); private // public // end; implementation uses //the uses var myLocalVar; procedure makeThisInstanceX(passMeTheVar:integer); begin myLocalVar:=passMeTheVar; end; //other procedures using myLocalVar //etc to the end; Now somewhere in another Form I've dropped this Frame onto the Design pane, sometimes two of these frames on one Form, and have it declared in the proper places, etc. Each is unique in that : ThisFlexibleUnit : TFlexibleUnit; ThatFlexibleUnit : TFlexibleUnit; and when I do a: ThisFlexibleUnit.makeThisInstanceX(var1); //want to behave in way "var1" ThatFlexibleUnit.makeThisInstanceX(var2); //want to behave in way "var2" it seems that they both share the same variable "myLocalVar". Am I doing this wrong, in principle? If this is the correct method then it's a matter of debugging what I have (which is too huge to post) but if this is not correct in principle then is there a way to do what I am suggesting? Thanks in advance, Stack Overflow - you guys (and gals!) are legendary.

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  • Is there any way to identify a unique user in Flash/Actionscript 3?

    - by VGambit
    I'm trying to make a vote/poll application in Flash using Actionscript 3. Is there any way to generate a specific ID that is unique to each user? The only other option I can think of is using the IP address, which is less than ideal in many cases (college campuses, shared Internet access, etc.). It needs to be the same number every time it is run on the same PC, but different for each user.

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  • Is there a better way to retrieve unique ID upon INSERT?

    - by Andy
    Hi, I am using the following MS SQL statement to insert records and return the unique auto-inc ID value all in one shot. Wonder if there is a simpler/faster/better way to do it? SET NOCOUNT ON; DECLARE @res table (ID bigint); INSERT INTO [Titles] ([Name],[Timestamp],[Title]) OUTPUT INSERTED.ID INTO @res VALUES ('Name','23 aug 2010','this is a title'); SELECT [ID] FROM @res;

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  • Get an iPad/iPhones unique information from your app?

    - by MikeN
    How do you get the unique identifying information from an iPhone/iPad within an app? For instance, I want my app to send support emails to my website for users who have problems and I need to uniquely identify the phone number/id of the device it is running on. Is this possible, forbidden?

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  • What's the right Java generic for a collection of elements with unique addressable indices?

    - by Rocreex
    I'm on my way to programming a database application and in our course we are told to implement a library of elements using one of the Java Collections. Each of the elements has a unique ID with which it's supposed to be addressed. Now I am wondering how this can be done. I though about using a ListArray but this won't work because the only way of addressing List elements is through the index which you can't control. Do you have some advice for me?

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  • How Can I Generate Random Unqiue Numbers in C#

    - by peace
    public int GenPurchaseOrderNum() { Random random = new Random(); _uniqueNum = random.Next(13287, 21439); return UniqueNum; } I removed unique constraint from the PONumber column in the db because an employee should only generate P.O. # when the deal is set. Otherwise, P.O. # would have 0. P.O. Number used to have unique constraint, this forces employee to generate P.O. in all cases so the db doesn't throw unique constraint error. Since i removed the unique constraint, any quote doesn't have P.O. will carry 0 value. Otherwise, a unique value is generated for P.O. #. However, i don't have a unique constraint in db which makes it hard for me to know whether the application generated P.O. # is unique or not. What should i do? I hope my question is clear enough

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  • Database indexes - what should they be

    - by WebweaverD
    Most of my database tables have a clear unique index through which lookups are done 90% of the time but I am a bit unsure on this one - I have a table which keeps track of user rating totals for items in my database, I now want to add another table, to track individual ratings with an ip address column to make sure no one can rate something twice. Since I can see this becoming a big, high use table it is important to optimize it correctly. (MYSQL table) This table will have the following fields: rating_id(always - unique), item_id (always - not unique), user_id (optional - not unique), ip_address (always - not unique), rating_value(always - not unique), has_review(bool) Now I envisions 90% the queries going something like this: When a user rates something - select where item_id = x and ip_address = y, (if rows = 0) insert rating When in user account pages - select where ip_address = x or username = y Now none of the fields searched on are unique, can I still use them as indexes (for example item _id and ip_address), can I have two indexes and will this still improve performance over a non indexed table?

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  • Is it possible to specify a generic constraint for a type parameter to be convertible FROM another t

    - by fostandy
    Suppose I write a library with the following: public class Bar { /* ... */ } public class SomeWeirdClass<T> where T : ??? { public T BarMaker(Bar b) { // ... play with b T t = (T)b return (T) b; } } Later, I expect users to use my library by defining their own types which are convertible to Bar and using the SomeWeirdClass 'factory'. public class Foo { public static explicit operator Foo(Bar f) { return new Bar(); } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } this will compile if i set where T : Foo but the problem is that I don't know about Foo at the library's compile time, and I actually want something more like where T : some class that can be instantiated, given a Bar Is this possible? From my limited knowledge it does not seem to be, but the ingenuity of the .NET framework and its users always surprises me... This may or not be related to the idea of static interface methods - at least, I can see the value in being able to specify the presence of factory methods to create objects (similar to the same way that you can already perform where T : new()) edit: Solution - thanks to Nick and bzIm - For other readers I'll provide a completed solution as I understand it: edit2: This solution requires Foo to expose a public default constructor. For an even stupider better solution that does not require this see the very bottom of this post. public class Bar {} public class SomeWeirdClass<T> where T : IConvertibleFromBar<T>, new() { public T BarMaker(Bar b) { T t = new T(); t.Convert(b); return t; } } public interface IConvertibleFromBar<T> { T Convert(Bar b); } public class Foo : IConvertibleFromBar<Foo> { public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } edit2: Solution 2: Create a type convertor factory to use: #region library defined code public class Bar {} public class SomeWeirdClass<T, TFactory> where TFactory : IConvertorFactory<Bar, T>, new() { private static TFactory convertor = new TFactory(); public T BarMaker(Bar b) { return convertor.Convert(b); } } public interface IConvertorFactory<TFrom, TTo> { TTo Convert(TFrom from); } #endregion #region user defined code public class BarToFooConvertor : IConvertorFactory<Bar, Foo> { public Foo Convert(Bar from) { return (Foo) from; } } public class Foo { public Foo(int a) {} public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } #endregion public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo, BarToFooConvertor> weird = new SomeWeirdClass<Foo, BarToFooConvertor>(); Foo f = weird.BarMaker(b); } }

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  • Is it possible to specify a generic constraint for a type parameter to be convertible FROM another t

    - by fostandy
    Suppose I write a library with the following: public class Bar { /* ... */ } public class SomeWeirdClass<T> where T : ??? { public T BarMaker(Bar b) { // ... play with b T t = (T)b return (T) b; } } Later, I expect users to use my library by defining their own types which are convertible to Bar and using the SomeWeirdClass 'factory'. public class Foo { public static explicit operator Foo(Bar f) { return new Bar(); } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } this will compile if i set where T : Foo but the problem is that I don't know about Foo at the library's compile time, and I actually want something more like where T : some class that can be instantiated, given a Bar Is this possible? From my limited knowledge it does not seem to be, but the ingenuity of the .NET framework and its users always surprises me... This may or not be related to the idea of static interface methods - at least, I can see the value in being able to specify the presence of factory methods to create objects (similar to the same way that you can already perform where T : new()) edit: Solution - thanks to Nick and bzIm - For other readers I'll provide a completed solution as I understand it: edit2: This solution requires Foo to expose a public default constructor. For an even stupider better solution that does not require this see the very bottom of this post. public class Bar {} public class SomeWeirdClass<T> where T : IConvertibleFromBar<T>, new() { public T BarMaker(Bar b) { T t = new T(); t.Convert(b); return t; } } public interface IConvertibleFromBar<T> { T Convert(Bar b); } public class Foo : IConvertibleFromBar<Foo> { public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo> weird = new SomeWeirdClass<Foo>(); Foo f = weird.BarMaker(b); } } edit2: Solution 2: Create a type convertor factory to use: #region library defined code public class Bar {} public class SomeWeirdClass<T, TFactory> where TFactory : IConvertorFactory<Bar, T>, new() { private static TFactory convertor = new TFactory(); public T BarMaker(Bar b) { return convertor.Convert(b); } } public interface IConvertorFactory<TFrom, TTo> { TTo Convert(TFrom from); } #endregion #region user defined code public class BarToFooConvertor : IConvertorFactory<Bar, Foo> { public Foo Convert(Bar from) { return (Foo) from; } } public class Foo { public Foo(int a) {} public static explicit operator Foo(Bar f) { return null; } public Foo Convert(Bar b) { return (Foo) b; } } #endregion public class Demo { public static void demo() { Bar b = new Bar(); SomeWeirdClass<Foo, BarToFooConvertor> weird = new SomeWeirdClass<Foo, BarToFooConvertor>(); Foo f = weird.BarMaker(b); } }

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  • How to user Hibernate @Valid constraint with Spring 3.x?

    - by Burak Dede
    I am working on simple form to validate fields like this one. public class Contact { @NotNull @Max(64) @Size(max=64) private String name; @NotNull @Email @Size(min=4) private String mail; @NotNull @Size(max=300) private String text; } I provide getter and setters hibernate dependencies on my classpath also.But i still do not get the how to validate simple form there is actually not so much documentation for spring hibernate combination. @RequestMapping(value = "/contact", method = RequestMethod.POST) public String add(@Valid Contact contact, BindingResult result) { .... } Could you explain it or give some tutorial , except original spring 3.x documentation

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  • Removing a default value from a Sql Server 2005 table

    - by Nikola Stjelja
    Hi, I have a tabel in an Sql Server 2005 database. I have the following column IndPL INT DEFAULT 0 NULL I want to change the column to be of the type NVARCHAR but I receive a constraint violation due to the fact that the column has a default value constraint attached to it. I need to find out how to remove a default value constraint from a table column or how to change the column type without impeding the constraint.

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  • Stop invalid data in a attribute with foreign key constraint using triggers?

    - by Eternal Learner
    How to specify a trigger which checks if the data inserted into a tables foreign key attribute, actually exists in the references table. If it exist no action should be performed , else the trigger should delete the inserted tuple. Eg: Consider have 2 tables R(A int Primary Key) and S(B int Primary Key , A int Foreign Key References R(A) ) . I have written a trigger like this : Create Trigger DelS BEFORE INSERT ON S FOR EACH ROW BEGIN Delete FROM S where New.A <> ( Select * from R;) ); End; I am sure I am making a mistake while specifying the inner sub query within the Begin and end Blocks of the trigger. My question is how do I make such a trigger ?

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  • How to generate a unique hash for a URL ?

    - by Jacques René Mesrine
    Given these two images from twitter. http://a3.twimg.com/profile_images/130500759/lowres_profilepic.jpg http://a1.twimg.com/profile_images/58079916/lowres_profilepic.jpg I want to download them to local filesystem & store them in a single directory. How shall I overcome name conflicts ? In the example above, I cannot store them as *lowres_profilepic.jpg*. My design idea is treat the URLs as opaque strings except for the last segment. What algorithms (implemented as f) can I use to hash the prefixes into unique strings. f( "http://a3.twimg.com/profile_images/130500759/" ) = 6tgjsdjfjdhgf f( "http://a1.twimg.com/profile_images/58079916/" ) = iuhd87ysdfhdk That way, I can save the files as:- 6tgjsdjfjdhgf_lowres_profilepic.jpg iuhd87ysdfhdk_lowres_profilepic.jpg I don't want a cryptographic algorithm as it this needs to be a performant operation.

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  • How to use map/reduce to handle more than 10000 unique keys for grouping in MongoDB?

    - by Magnus Johansson
    I am using MongoDB v1.4 and the mongodb-csharp driver and I try to group on a data store that has more than 10000 keys, so I get this error: assertion: group() can't handle more than 10000 unique keys using c# code like this: Document query = new Document().Append("group", new Document() .Append("key", new Document().Append("myfieldname", true)) .Append("$reduce", new CodeWScope( "function(obj,prev) { prev.count++; }")) .Append("initial", new Document().Append("count", 0)) .Append("ns", "myitems")); I read that I should use map/reduce, but I can't figure out how. Can somebody please shed some light on how to use map/reduce? Or is there any other way to get around this limitation? Thanks.

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  • Is it possible to bundle a unique file for each copy of iPhone app downloaded from App Store?

    - by futureelite7
    Hi, I would like to verify the identity of each instance of the iPhone application that a user might use to connect to my service. To that end, I would like each instance of the iPhone app downloaded to include a certificate that I generate, or even some sort of UUID that I have generated. Does the App Store support the inclusion of unique files in an app bundle? Or, must such identifiers be downloaded only after the app is installed? If that is the case, is there a mechanism to ensure that the app downloaded is trusted (from me), instead of from an impersonator?

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  • Java generics: What is the compiler's issue here? ("no unique maximal instance")

    - by Epaga
    I have the following methods: public <T> T fromJson( Reader jsonData, Class<T> clazz ) { return fromJson( jsonData, (Type)clazz ); } public <T> T fromJson( Reader jsonData, Type clazz ) { ... } The compiler is saying about the first method: type parameters of <T>T cannot be determined; no unique maximal instance exists for type variable T with upper bounds T,java.lang.Object return fromJson( jsonData, (Type)clazz ); ^ What is the problem?

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  • Rails, How can I combine multiple model attributes to create a unique permalink using permalink_fu?

    - by Ranknoodle
    Can Permalink_fu combine 2 or more model attributes to create a unique permalink? Let's say I have a Business Model, this model contains :name, :address, :phone, :city, :state, :country etc. attributes. Right now I have permalink set up in this model only for :name has_permalink :name So I would get "/biz/name". However I would like to combine the Business name, city, and a incremental number if there are more than 1 location in the city for that business. For example I would like to use: "/biz/joes-coffee-shack-chicago" for the permalink or if a multple location business "/biz/starbucks-chicago-92" Is this possible with the current permalink_fu plugin or some fork of permalink_fu? Or will this require some modification to the permalink_fu plugin?

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  • Easiest way of checking if a string consists of unique characters?

    - by serg555
    I need to check in Java if a word consists of unique letters (case insensitive). As straight solution is boring, I came up with: For every char in a string check if indexOf(char) == lastIndexOf(char). Add all chars to HashSet and check if set size == string length. Convert a string to a char array, sort it alphabetically, loop through array elements and check if c[i] == c[i+1]. Currently I like #2 the most, seems like the easiest way. Any other interesting solutions?

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  • How do i create a view that can filter unique titles from a checkbox?

    - by buws
    I'm currently creating a view in Drupal that contains a number of fields. What I want to do is to create an exposed filter that is able to filter duplicate titles. The filter would be a checkbox. This is an example of the list NAME TIME RACE DISTANCE John Doe 2.07.54 Boston Marathon 42km Jane Boss 2.15.21 Boston Marathon 42km John Doe 2.02.22 Boston Marathon 42km Jane Boss 2.15.44 Boston Marathon 42km What I want to have is an exposed filter that only shows one unique NAME and sorts it by its best time. The resulting list would look as follows: NAME TIME RACE DISTANCE Jane Boss 2.15.21 Boston Marathon 42km John Doe 2.02.22 Boston Marathon 42km Any help is appreciated!

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