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  • Is there a JSON library that can serialize Proxy objects?

    - by gmoore
    Using ActiveObjects as my ORM and Gson as my JSON processor. Ran into a problem going toJson from persisted objects. The problem is that my persisted class is actually an Interface and AO is proxying that object under the hood. Here's some sample code: Venue venue = manager.get(Venue.class, id); gson.toJson(venue); Comes up with this exception: java.lang.UnsupportedOperationException: Expecting parameterized type, got interface java.lang.reflect.InvocationHandler. Are you missing the use of TypeToken idiom? See http://sites.google.com/site/gson/gson-user-guide#TOC-Serializing-and... Because venue.getClass().getName() gives: $Proxy228 I've tried a few solutions in various combinations: gsonBuilder.registerTypeAdapter(Venue.class, newVenueSerializer()); Type listType = new TypeToken<Venue>() {}.getType(); Nothing has worked so far and I'm using a wonky field-by-field workaround. Any suggestions? I'm not married to Gson, so if there's an alternative library that can do this I'd be happy to use it.

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  • How to enforce users to create objects of class derived from mine with "new" only?

    - by sharptooth
    To implement reference counting we use an IUnknown-like interface and a smart pointer template class. The interface has implementation for all the reference-count methods, including Release(): void IUnknownLike::Release() { if( --refCount == 0 ) { delete this; } } The smart pointer template class has a copy constructor and an assignment operator both accepting raw pointers. So users can do the following: class Class : public IUnknownLike { }; void someFunction( CSmartPointer<Class> object ); //whatever function Class object; someFunction( &object ); and the program runs into undefined behavior - the object is created with reference count zero, the smart pointer is constructed and bumps it to one, then the function returns, smart pointer is destroyed, calls Release() which leads to delete of a stack-allocated variable. Users can as well do the following: struct COuter { //whatever else; Class inner;// IUnknownLike descendant }; COuter object; somefunction( &object.Inner ); and again an object not created with new is deleted. Undefined behavior at its best. Is there any way to change the IUnknownLike interface so that the user is forced to use new for creating all objects derived from IUnknownLike - both directly derived and indirectly derived (with classes in between the most derived and the base)?

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  • Is it poor design to create objects that only execute code during the constructor?

    - by Curtix
    In my design I am using objects that evaluate a data record. The constructor is called with the data record and type of evaluation as parameters and then the constructor calls all of the object's code necessary to evaluate the record. This includes using the type of evaluation to find additional parameter-like data in a text file. There are in the neighborhood of 250 unique evaluation types that use the same or similar code and unique parameters coming from the text file. Some of these evaluations use different code so I benefit a lot from this model because I can use inheritance and polymorphism. Once the object is created there isn't any need to execute additional code on the object (at least for now) and it is used more like a struct; its kept on a list and 3 properties are used later. I think this design is the easiest to understand, code, and read. A logical alternative I guess would be using functions that return score structs, but you can't inherit from methods so it would make it kind of sloppy imo. I am using vb.net and these classes will be used in an asp.net web app as well as in a distributed app. thanks for your input

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  • (illustrator scripting) how to release objects to layers(sequence) but retain object's name?

    - by Eugene
    Hi, I've asked the same question to adobe scripting forum. but seems there are not many forum users there, and I'm asking the same question here. I was writing my first illustrator script to export all layers to png files with layer structure converted to file structure. I found there are many layers that my script can't detect and found out that they are not actually layers but objects(or groups). Found a layer menu (release to layers), but doesn't quite solve the problem perfectly. initially I have this layer 001 object 01 object 1 object 2 release to layers(sequence) on object 01 gives layer 001 layer 91(whatever the layer number illustrator gives when release to layers are performed) layer 92 object 1 layer 93 object 2 now I need to convert them to (so that layer can retain the name of the object) layer 001 layer 01 layer 1 object 1 layer 2 object 2 I have hundreds of layer 001, and couple thousands of object 01, and wonder if anything can be done with script to do this... If it's possible to detect object in a script, I could rewrite the 'release to layers' functionality in script maybe. Any help would be greatly appreciated.

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  • C# How to create various objects at runtime that can hold strongly typed data?

    - by JL
    Is it possible to create objects at runtime without having to have hard coded class definitions, then populate properties with primitives or even strongly typed data types? For example: Lets say I want to an XML config file that could hold configuration values for connecting to various systems in an SOA application. In C# I read in these values, but for each system the properties are different (e.g: SQL might have a connection string, while SharePoint might need a username + password + domain + url, while yet an smtp server would need username + password + port + url) So instead of creating static classes as follows public class SharePointConfiguration or public class SQLConfiguration, then have each class with custom properties (this is cumbersome) Is there not a more preferred way to achieve this, without using 1990's methods, in otherwords it would still be nice to have intellisense and code completion and named properties. Since this collection of properties (object) would be passed within the class and possible to other classes from function to function I am also wondering where this class definition would get defined if its all happening at run time. Any recommendations, and hope the question was clear enough. Would like to use language features, not hacks. Thank you.

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  • What techniques can I employ to create a series of UI Elements from a collection of objects using WP

    - by elggarc
    I'm new to WPF and before I dive in solving a problem in completely the wrong way I was wondering if WPF is clever enough to handle something for me. Imagine I have a collection containing objects. Each object is of the same known type and has two parameters. Name (a string) and Picked (a boolean). The collection will be populated at run time. I would like to build up a UI element at run time that will represent this collection as a series of checkboxes. I want the Picked parameter of any given object in the collection updated if the user changes the selected state of the checkbox. To me, the answer is simple. I iterate accross the collection and create a new checkbox for each object, dynamically wiring up a ValueChanged event to capture when Picked should be changed. It has occured to me, however, that I may be able to harness some unknown feature of WPF to do this better (or "properly"). For example, could data binding be employed here? I would be very interested in anyone's thoughts. Thanks, E FootNote: The structure of the collection can be changed completely to better fit any chosen solution but ultimately I will always start from, and end with, some list of string and boolean pairs.

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  • Nested Routes Show Action: What objects does it expect?

    - by NoahClark
    Here is the relevant line from my rake routes: client_note GET /clients/:client_id/notes/:id(.:format) notes#show When I try passing in the objects like <%= client_note_path([client, @notes.first]) %>> I get: No route matches {:action=>"show", :controller=>"notes", :client_id=>[#<Client id: 5, ... , #<Note id: 9, ...]} Which made me think to try a client ID. So, I tried: <%= client_note_path([client.id, @notes.first]) %> which gives me: No route matches {:action=>"show", :controller=>"notes", :client_id=>[5, #<Note id: 9,content: "He just bought a brand new bobcat, be sure to charg...", client_id: 5, created_at: "2012-06-11 16:18:16", updated_at: "2012-06-11 16:18:16">]} Which, made me want to try just passing in a client ID. <%= client_note_path(client.id) %> No route matches {:action=>"show", :controller=>"notes", :client_id=>5} Still not what I'm looking for. I want to be able to show an individual note which can normally be found at a url like looks like: http://localhost:3000/clients/2/notes/3/

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  • How can I get my business objects layer to use the management layer in their methods?

    - by Tom Pickles
    I have a solution in VS2010 with several projects, each making up a layer within my application. I have business entities which are currently objects with no methods, and I have a management layer which references the business entities layer in it's project. I now think I have designed my application poorly and would like to move methods from helper classes (which are in another layer) into methods I'll create within the business entities themselves. For example I have a VirtualMachine object, which uses a helper class to call a Reboot() method on it which passes the request to the management layer. The static manager class talks to an API that reboots the VM. I want to move the Reboot() method into the VirtualMachine object, but I will need to reference the management layer: public void Reboot() { VMManager.Reboot(this.Name); } So if I add a reference to my management project in my entities project, I get the circular dependency error, which is how it should be. How can I sort this situation out? Do I need to an yet another layer between the entity layer and the management layer? Or, should I just forget it and leave it as it is. The application works ok now, but I am concerned my design isn't particularly OOP centric and I would like to correct this.

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  • [C#] How do I make hierarchy of objects from two alternating classes?

    - by Millicent
    Here's the scenario: I have two classes ("Page" and "Field"), that are descended from a common class ("Pield"). They represent tags in an XML file and are in the following hierarchy: <page> <field> <page> ... </page> ... </field> ... </page> I.e.: Page and Field objects are in a hierarchy of alternating type (there may be more than one Page or Field to each rung of the hierarchy). Every Field and Page object has a parent property, which points to the respective parent object of the other type. This is not a problem unless the parent-child mechanism is controlled by the base class (Pield), which is shared by the two descended classes (Page and Field). Here is one try, that fails at the line "Pield child = new Pield(pchild, this);": class Pield<T> { private T _pield_parent; ... private void get_children() { ... Pield<Page> child = new Pield<Page>(pchild, this); ... } ... } class Page : Pield<Field> { ... } class Field : Pield<Page> { ... } Any ideas about how to solve this elegantly? Best, Millicent

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  • How do I code a tree of objects in Haskell with pointers to parent and children?

    - by axilmar
    I've got the following problem: I have a tree of objects of different classes where an action in the child class invalidates the parent. In imperative languages, it is trivial to do. For example, in Java: public class A { private List<B> m_children = new LinkedList<B>(); private boolean m_valid = true; public void invalidate() { m_valid = false; } public void addChild(B child) { m_children.add(child); child.m_parent = this; } } public class B { public A m_parent = null; private int m_data = 0; public void setData(int data) { m_data = 0; m_parent.invalidate(); } } public class Main { public static void main(String[] args) { A a = new A(); B b = new B(); b.setData(0); //invalidates A } } How do I do the above in Haskell? I cannot wrap my mind around this, since once I construct an object in Haskell, it cannot be changed. I would be much obliged if the relevant Haskell code is posted.

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  • How duplicate an object in a list and update property of duplicated objects ?

    - by user359706
    Hello What would be the best way to duplicate an object placed in a list of items and change a property of duplicated objects ? I thought proceed in the following manner: - get object in the list by "ref" + "article" - Cloned the found object as many times as desired (n times) - Remove the object found - Add the clones in the list What do you think? A concrete example: Private List<Product> listProduct; listProduct= new List<Product>(); Product objProduit_1 = new Produit; objProduct_1.ref = "001"; objProduct_1.article = "G900"; objProduct_1.quantity = 30; listProducts.Add(objProduct_1); ProductobjProduit_2 = new Product; objProduct_2.ref = "002"; objProduct_2.article = "G900"; objProduct_2.quantity = 35; listProduits.Add(objProduct_2); desired method: public void updateProductsList(List<Product> paramListProducts,Produit objProductToUpdate, int32 nbrDuplication, int32 newQuantity){ ... } Calling method example: updateProductsList(listProducts,objProduct_1,2,15); Waiting result: Replace follow object : ref = "001"; article = "G900"; quantite = 30; By: ref = "001"; article = "G900"; quantite = 15; ref = "001"; article = "G900"; quantite = 15; The Algorithm is correct? Would you have an idea of the method implementation "updateProductsList" Thank you in advance for your help.

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  • Generating an identifier for objects so that they can be added to a hashtable I have created

    - by dukenukem
    I have a hashtable base class and I am creating different type of hashtable by deriving from it. I only allow it to accept objects that implement my IHashable interface.For example - class LinearProbingHashTable<T> : HashTableBase<T> where T: IHashable { ... ... ... } interface IHashable { /** * Every IHashable implementation should provide an indentfying value for use in generating a hash key. */ int getIdentifier(); } class Car : IHashable { public String Make { get; set; } public String Model { get; set; } public String Color { get; set; } public int Year { get; set; } public int getIdentifier() { /// ??? } } Can anyone suggest a good method for generating an identifier for the car that can be used by the hash function to place it in the hash table? I am actually really looking for a general purpose solution to generating an id for any given class. I would like to have a base class for all classes, HashableObject, that implements IHashable and its getIdentifier method. So then I could just derive from HashableObject which would automatically provide an identifier for any instances. Which means I wouldn't have to write a different getIdentifier method for every object I add to the hashtable. public class HashableObject : IHashable { public int getIdentifier() { // Looking for code here that would generate an id for any object... } } public class Dog : HashableObject { // Dont need to implement getIdentifier because the parent class does it for me }

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  • Deleting multiple objects in a AWS S3 bucket with s3curl.pl?

    - by user183394
    I have been trying to use the AWS "official" command line tool s3curl.pl to test out the recently announced multi-object delete. Here is what I have done: First, I tested out the s3curl.pl with a set of credentials without a hitch: $ s3curl.pl --id=s3 -- http://testbucket-0.s3.amazonaws.com/|xmllint --format - % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 884 0 884 0 0 4399 0 --:--:-- --:--:-- --:--:-- 5703 <?xml version="1.0" encoding="UTF-8"?> <ListBucketResult xmlns="http://s3.amazonaws.com/doc/2006-03-01/"> <Name>testbucket-0</Name> <Prefix/> <Marker/> <MaxKeys>1000</MaxKeys> <IsTruncated>false</IsTruncated> <Contents> <Key>file_1</Key> <LastModified>2012-03-22T17:08:17.000Z</LastModified> <ETag>"ee0e521a76524034aaa5b331842a8b4e"</ETag> <Size>400000</Size> <Owner> <ID>e6d81ea69572270e58d3814ab674df8c8f1fd5d502669633a4951bdd5185f7f4</ID> <DisplayName>zackp</DisplayName> </Owner> <StorageClass>STANDARD</StorageClass> </Contents> <Contents> <Key>file_2</Key> <LastModified>2012-03-22T17:08:19.000Z</LastModified> <ETag>"6b32cbf8219a59690a9f69ba6ff3f590"</ETag> <Size>600000</Size> <Owner> <ID>e6d81ea69572270e58d3814ab674df8c8f1fd5d502669633a4951bdd5185f7f4</ID> <DisplayName>zackp</DisplayName> </Owner> <StorageClass>STANDARD</StorageClass> </Contents> </ListBucketResult> Then, I following the s3curl.pl's usage instructions: s3curl.pl --help Usage /usr/local/bin/s3curl.pl --id friendly-name (or AWSAccessKeyId) [options] -- [curl-options] [URL] options: --key SecretAccessKey id/key are AWSAcessKeyId and Secret (unsafe) --contentType text/plain set content-type header --acl public-read use a 'canned' ACL (x-amz-acl header) --contentMd5 content_md5 add x-amz-content-md5 header --put <filename> PUT request (from the provided local file) --post [<filename>] POST request (optional local file) --copySrc bucket/key Copy from this source key --createBucket [<region>] create-bucket with optional location constraint --head HEAD request --debug enable debug logging common curl options: -H 'x-amz-acl: public-read' another way of using canned ACLs -v verbose logging Then, I tried the following, and always got back error. I would appreciated it very much if someone could point out where I made a mistake? $ s3curl.pl --id=s3 --post multi_delete.xml -- http://testbucket-0.s3.amazonaws.com/?delete <?xml version="1.0" encoding="UTF-8"?> <Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message><StringToSignBytes>50 4f 53 54 0a 0a 0a 54 68 75 2c 20 30 35 20 41 70 72 20 32 30 31 32 20 30 30 3a 35 30 3a 30 38 20 2b 30 30 30 30 0a 2f 7a 65 74 74 61 72 2d 74 2f 3f 64 65 6c 65 74 65</StringToSignBytes><RequestId>707FBE0EB4A571A8</RequestId><HostId>mP3ZwlPTcRqARQZd6gU4UvBrxGBNIVa0VVe5p0rqGmq5hM65RprwcG/qcXe+pmDT</HostId><SignatureProvided>edkNGuugiSFe0ku4eGzkh8kYgHw=</SignatureProvided><StringToSign>POST Thu, 05 Apr 2012 00:50:08 +0000 The file multi_delete.xml contains the following: cat multi_delete.xml <?xml version="1.0" encoding="UTF-8"?> <Delete> <Quiet>true</Quiet> <Object> <Key>file_1</Key> <VersionId> </VersionId>> </Object> <Object> <Key>file_2</Key> <VersionId> </VersionId> </Object> </Delete> Thanks for any help! --Zack

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  • Is there a simple way to backup and restore all Microsoft SQL Server database objects related to a p

    - by Nathan Hartley
    I would like to backup, not only the databases that belong to a particular application living on a shared server, but also, those things that get stored outside of the database; the server accounts, jobs, maintenance plans and whatever else I can't think of at the moment. This backup should be complete enough that it's corresponding restore will recreate the entire application on a different SQL server. This seems like a problem others must have dealt with in the past. So before I embark on creating custom Powershell scripts for each application, I have come to ask you... Can you help?

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  • Does anyone know of a program that can search database objects (i.e. StoredProcedures) for keywords?

    - by hcabnettek
    Hi All, Is there such a tool that would look through a group of stored procedures for source code keywords? A client has a lot of business logic coded into their database and I need to find where it is using certain strings of text? I.E. what procedure contains 'was applied to their balance', so I can refactor that out into business logic. Does anyone know of such a tool? perhaps something from Red-Gate? Thanks, ~ck in San Diego

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  • Fix elements within objects at their position? (Prevent movement when resizing)

    - by Skadier
    I would like to know if it is possible to fix elements at their absolute position within custom elements in InDesign CS5? I created a kind of speech bubble and I would like to place a stripline within this bubble to separate two content areas. Just a little scheme to show the desired layout as Pseudo-Markup :D <speech-bubble> <textbox>HEADER SECTION</textbox> <stripline> <textbox>Some other text</textbox> </speech-bubble> I created something like this but with two separate elements which aren't connected. So I have to select both of them in order to move the whole bubble. Then I tried to connect them using Object->Paths->Create linked path but then the stripline moves and the HEADER SECTION moves too. All in all I would like to have a speech bubble which can be resized in order to hold more text but it shouldn't make the HEADER_SECTION larger or move the stripline. Hope you understand what I mean :D Thanks in advance!

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  • Django QuerySet filter method returns multiple entries for one record

    - by Yaroslav
    Trying to retrieve blogs (see model description below) that contain entries satisfying some criteria: Blog.objects.filter(entries__title__contains='entry') The results is: [<Blog: blog1>, <Blog: blog1>] The same blog object is retrieved twice because of JOIN performed to filter objects on related model. What is the right syntax for filtering only unique objects? Data model: class Blog(models.Model): name = models.CharField(max_length=100) def __unicode__(self): return self.name class Entry(models.Model): title = models.CharField(max_length=100) blog = models.ForeignKey(Blog, related_name='entries') def __unicode__(self): return self.title Sample data: b1 = Blog.objects.create(name='blog1') e1 = Entry.objects.create(title='entry 1', blog=b1) e1 = Entry.objects.create(title='entry 2', blog=b1)

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  • Unable to cast lists with Reflection in C#

    - by DrLazer
    I am having a lot of trouble with Reflection in C# at the moment. The app I am writing allows the user to modify the attributes of certain objects using a config file. I want to be able to save the object model (users project) to XML. The function below is called in the middle of a foreach loop, looping through a list of objects that contain all the other objects in the project within them. The idea is, that it works recursively to translate the object model into XML. Dont worry about the call to "Unreal" that just modifes the name of the objects slightly if they contain certain words. private void ReflectToXML(object anObject, XmlElement parentElement) { Type aType = anObject.GetType(); XmlElement anXmlElement = m_xml.CreateElement(Unreal(aType.Name)); parentElement.AppendChild(anXmlElement); PropertyInfo[] pinfos = aType.GetProperties(); //loop through this objects public attributes foreach (PropertyInfo aInfo in pinfos) { //if the attribute is a list Type propertyType = aInfo.PropertyType; if ((propertyType.IsGenericType)&&(propertyType.GetGenericTypeDefinition() == typeof(List<>))) { List<object> listObjects = (aInfo.GetValue(anObject,null) as List<object>); foreach (object aListObject in listObjects) { ReflectToXML(aListObject, anXmlElement); } } //attribute is not a list else anXmlElement.SetAttribute(aInfo.Name, ""); } } If an object attributes are just strings then it should be writing them out as string attributes in the XML. If an objects attributes are lists, then it should recursively call "ReflectToXML" passing itself in as a parameter, thereby creating the nested structure I require that nicely reflect the object model in memory. The problem I have is with the line List<object> listObjects = (aInfo.GetValue(anObject,null) as List<object>); The cast doesn't work and it just returns null. While debugging I changed the line to object temp = aInfo.GetValue(anObject,null); slapped a breakpoint on it to see what "GetValue" was returning. It returns a "Generic list of objects" Surely I should be able to cast that? The annoying thing is that temp becomes a generic list of objects but because i declared temp as a singular object, I can't loop through it because it has no Enumerator. How can I loop through a list of objects when I only have it as a propertyInfo of a class? I know at this point I will only be saving a list of empty strings out anyway, but thats fine. I would be happy to see the structure save out for now. Thanks in advance

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  • How do I sort an array of Person Objects by using compareto()?

    - by Adam
    Here is my code: > import java.util.Scanner; import java.util.Arrays; /** This class tests the Person class. */ public class PersonDemo { public static void main(String[] args) { int count = 0; Scanner in = new Scanner(System.in); boolean more = false; Person first = null; Person last = null; while (more) { System.out.println( "Please enter the person's name or a blank line to quit"); String name = in.nextLine(); if (name.equals("")) more = false; else { Person p = new Person(name); //new person object created with inputted name Person[] people = new Person[10]; //new array of 10 person objects people[count] = p; //declare person object with index of variable count as the new person object first = people[count]; // I have no idea what to do here. This is where I'm stuck. last = people[count]; // I can't figure out what to do with this either. first.compareTo(p); //call compareTo method on first and new person object last.compareTo(p); //call compareTo method on last and new person object count++; // increase count variable } } System.out.println("First: " + first.toString()); System.out.println("Last: " + last.toString()); } } And the Person class: /** A person with a name. */ public class Person implements Comparable { /** * Constructs a Person with a name. * @param aName the person's name */ public Person(String aName) { name = aName; } public String getName() { return name; } @Override public int compareTo(Object otherObject) { Person other = (Person)otherObject; if (name.compareTo(other.name) < 0) return -1; if (name.compareTo(other.name) > 0) return 1; return 0; } /** Returns a string representation of the object. @return name of Person */ public String toString() { return "[name=" + name + "]"; } private String name; }

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  • What is the most stupid coded solution you have read/improved/witnessed?

    - by Rigo Vides
    And for stupid I mean Illogical, non-effective, complex(the bad way), ugly code style. I will start: We had a requirement there when we needed to hide certain objects given the press of a button. So this framework we were using at the time provided a way to tag objects and retrieve all the objects with a certain tag in a complete iterable collection. So I presented the most logically solution given these conditions to my partner: Me: you know, tag all the objects we needed to hide with the same tag, then call the function to get them all, iterate trough them and make them hidden. Partner: I don't know, that is hardcoding for me... Me: So what do you suggest? 20 mins later... Partner: I don't know... let's put a tag to all the objects to be hidden like this, 1, 2, 3, 4, 5, 6, 7 (and so for each object to be hidden), Then we make a for from 1 to n (where n was the number of objects to hide) and we hide them all there!

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  • Linq to Sql, Repositories, and Asp.Net MVC ViewData: How to remove redundancy?

    - by Dr. Zim
    Linq to SQL creates objects which are IQueryable and full of relations. Html Helpers require specific interface objects like IEnumerable<SelectListItem>. What I think could happen: Reuse the objects from Linq to SQL without all the baggage, i.e., return Pocos from the Linq to SQL objects without additional Domain Model classes? Extract objects that easily convert to (or are) Html helper objects like the SelectListItem enumeration? Is there any way to do this without breaking separation of concerns? Some neat oop trick to bridge the needs? For example, if this were within a repository, the SelectListItem wouldn't be there. The select new is a nice way to cut out an object from the Linq to SQL without the baggage but it's still referencing a class that shouldn't be referenced: IEnumerable<SelectListItem> result = (from record in db.table select new SelectListItem { Selected = record.selected, Text= record.Text, Value= record.Value } ).AsEnumerable();

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  • Creating many new instances vs reusing them?

    - by Hugo Riley
    I have multiple business entities in VB.NET Windows Forms application. Right now they are instanced on application startup and used when needed. They hold descriptions of business entities and methods for storing and retrieving data. To cut the long story short, they are somewhat heavy objects to construct (they have some internal dictionaries and references to other objects) created and held in one big global variable called "BLogic". Should I refactor this so that each object is created when needed and released when out of scope? Then every event on UI will probably create a few of this objects. Should I strive to minimize creation of new objects or to minimize number of static and global objects? Generally I am trying to minimize the scope of every variable but should I treat this business logic objects specially?

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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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  • Sessions not persisting between requests

    - by klonq
    My session objects are only stored within the request scope on google app engine and I can't figure out how to persist objects between requests. The docs are next to useless on this matter and I can't find anyone who's experienced a similar problem. Please help. When I store session objects in the servlet and forward the request to a JSP using: getServletContext().getRequestDispatcher("/example.jsp").forward(request,response); Everything works like it should. But when I store objects to the session and redirect the request using: response.sendRedirect("/example/url"); The session objects are lost to the ether. In fact when I dump session key/value pairs on new requests there is absolutely nothing, session objects only appear within the request scope of servlets which create session objects. It appears to me that the objects are not being written to Memcache or Datastore. In terms of configuring sessions for my application I have set <sessions-enabled>true</sessions-enabled> In appengine-web.xml. Is there anything else I am missing? The single paragraph of documentation on sessions also notes that only objects which implement Serializable can be stored in the session between requests. I have included an example of the code which is not working below. The obvious solution is to not use redirects, and this might be ok for the example given below but some application data does need to be stored in the session between requests so I need to find a solution to this problem. EXAMPLE: The class FlashMessage gives feedback to the user from server-side operations. if (email.send()) { FlashMessage flash = new FlashMessage(FlashMessage.SUCCESS, "Your message has been sent."); session.setAttribute(FlashMessage.SESSION_KEY, flash); // The flash message will not be available in the session object in the next request response.sendRedirect(URL.HOME); } else { FlashMessage flash = new FlashMessage(FlashMessage.ERROR, FlashMessage.INVALID_FORM_DATA); session.setAttribute(FlashMessage.SESSION_KEY, flash); // The flash message is displayed without problem getServletContext().getRequestDispatcher(Templates.CONTACT_FORM).forward(request,response); } FlashMessage.java import java.io.Serializable; public class FlashMessage implements Serializable { private static final long serialVersionUID = 8109520737272565760L; // I have tried using different, default and no serialVersionUID public static final String SESSION_KEY = "flashMessage"; public static final String ERROR = "error"; public static final String SUCCESS = "success"; public static final String INVALID_FORM_DATA = "Your request failed to validate."; private String message; private String type; public FlashMessage (String type, String message) { this.type = type; this.message = message; } public String display(){ return "<div id='flash' class='" + type + "'>" + message + "</div>"; } }

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