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• XMLHttpRequest() and outputting csv file

  - by sjw

  Initially, I developed a javascript function to use window.open to post contents of a form to a new window which simply opened the new window and initiated a csv file download. Now on reflection, I find the opening of the window superfluous and am trying to just execute a XMLHttpRequest() to download the csv. I am not getting what I want and I'm not 100% sure that I can so I thought I'd ask here for some assistance. When a form is submitted, I want to take all the form values and post them to another page which builds an SQL string and builds a csv based on the contents. (This I can do and works fine with XMLHttpRequest() as seen below) var xhReq = new XMLHttpRequest(); var parameters = ""; for ( i=0; i<formObj.elements.length; i++ ) { parameters += formObj.elements[i].name + "=" + encodeURI( formObj.elements[i].value ) + "&"; } xhReq.open("POST", outputLocation, false); xhReq.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); xhReq.setRequestHeader("Content-length", parameters.length); xhReq.setRequestHeader("Connection", "close"); xhReq.send(parameters); document.write(xhReq.responseText); The code above calls the page ok, builds the csv ok, but it outputs the contents into the current browser window instead of initiating a csv file download. Can I achieve what I need using XMLHttpRequest() or am I going it about it the wrong way? Thanks

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• Java Input/Output streams for unnamed pipes created in native code?

  - by finrod

  Is there a way to easily create Java Input/Output streams for unnamed pipes created in native code? Motivation: I need my own implementation of the Process class. The native code spawns me a new process with subprocess' IO streams redirected to unnamed pipes. Problem: The file descriptors for correct ends of those pipes make their way to Java. At this point I get stuck as I cannot create a new FileDescriptor which I could pass to FileInput/FileOutput stream. I have used reflection to get around the problem and got communication with a simple bouncer sub-process running. However I have a notion that it is not the cleanest way to go. Have you used this approach? Do you see any problems with this approach? (the platform will never change) Searching around the internets revealed similar solution using native code. Any thoughts before I dive into heavy testing of this approach are very welcome. I would like to give a shot to existing code before writing my own IO stream implementations... Thank you.

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• Find the number of congruent triangles?

  - by avd

  Say I have a square from (0,0) to (z,z). Given a triangle within this square which has integer coordinates for all its vertices. Find out the number of triangles within this square which are congruent to this triangle and have integer coordinates. My algorithm is as follows-- 1) Find out the minimum bounding rectangle(MBR) for the given triangle. 2) Find out the number of congruent triangles, y within that MBR, obtained after reflection, rotation of the given triangle. y can be either 2,4 or 8. 3) Now find out how many such MBR's can be drawn within the given big square, say x; (This is similar to finding number of squares on a chess board) 4) x*y is the required answer. Am I counting some triangles more than once or I am missing something by this algorithm? It is a problem on online judge? It gives me wrong answer. I have thought a lot about it, but I am not able to figure it out.

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• JSF 2 - clearing component attributes on page load?

  - by jamiebarrow

  Hi, The real question: Is there a way to clear certain attributes for all components on an initial page load? Background info: In my application, I have a JSF 2.0 frontend layer that speaks to a service layer (the service layer is made up of Spring beans that get injected to the managed beans). The service layer does its own validation, and I do the same validation in the frontend layer using my own validator classes to try and avoid code duplication somehow. These validator classes aren't JSF validators, they're just POJOs. I'm only doing validation on an action, so in the action method, I perform validation, and only if it's valid do I call through to the service layer. When I do my validation, I set the styleClass and title on the UIComponents using reflection (so if the UIComponent has the setStyleClass(:String) or setTitle(:String) methods, then I use them). This works nicely, and on a validation error I see a nicely styled text box with a popup containing the error message if I hover over it. However, since the component is bound to a Session Scoped Managed Bean, it seems that these attributes stick. So if I navigate away and come back to the same page, the styleClass and title are still in the error state. Is there a way to clear the styleClass and title attributes on each initial page load? Thanks, James P.S. I'm using the action method to validate because of some issues I had before with JSF 1.2 and it's validation methods, but can't remember why... so that's why I'm using the action method to validate.

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• Calculating collision for a moving circle, without overlapping the boundaries

  - by Robert Vella

  Let's say I have circle bouncing around inside a rectangular area. At some point this circle will collide with one of the surfaces of the rectangle and reflect back. The usual way I'd do this would be to let the circle overlap that boundary and then reflect the velocity vector. The fact that the circle actually overlaps the boundary isn't usually a problem, nor really noticeable at low velocity. At high velocity it becomes quite clear that the circle is doing something it shouldn't. What I'd like to do is to programmatically take reflection into account and place the circle at it's proper position before displaying it on the screen. This means that I have to calculate the point where it hits the boundary between it's current position and it's future position -- rather than calculating it's new position and then checking if it has hit the boundary. This is a little bit more complicated than the usual circle/rectangle collision problem. I have a vague idea of how I should do it -- basically create a bounding rectangle between the current position and the new position, which brings up a slew of problems of it's own (Since the rectangle is rotated according to the direction of the circle's velocity). However, I'm thinking that this is a common problem, and that a common solution already exists. Is there a common solution to this kind of problem? Perhaps some basic theories which I should look into?

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• What programming technique not done by you, was ahead of its time?

  - by Ferds

  There are developers who understand a technology and produce a solution months or years ahead of its time. I worked with a guy who designed an system using C# beta which would monitor different system components on several servers. He used SQL Server that would pick up these system monitoring components (via reflection) and would instantiate them via an NT Service. The simplicity in this design, was that another developer (me), who understood part of a system, would produce a component that could monitor it, as he had the specialized knowledge of that part of the system. I would derive from the monitor base class (to start, stop and log info), install on the monitoring server GAC and then add an entry to the components table in sql server. Then the main engine would pick up this component and do its magic. I understood parts of it, but couldn't work out by derive from a base class, why add to the GAC etc. This was 6 years ago and it took me months to realize what he achieved. What programming technique not done by you was ahead of its time? EDIT : Techniques that you have seen at work or journals/blogs - I don't mean historically over years.

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• JPA entitylisteners and @embeddable

  - by seanizer

  I have a class hierarchy of JPA entities that all inherit from a BaseEntity class: @MappedSuperclass @EntityListeners( { ValidatorListener.class }) public abstract class BaseEntity implements Serializable { // other stuff } I want all entities that implement a given interface to be validated automatically on persist and/or update. Here's what I've got. My ValidatorListener: public class ValidatorListener { private enum Type { PERSIST, UPDATE } @PrePersist public void checkPersist(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.PERSIST); } } @PreUpdate public void checkUpdate(final Object entity) { if (entity instanceof Validateable) { this.check((Validateable) entity, Type.UPDATE); } } private void check(final Validateable entity, final Type persist) { switch (persist) { case PERSIST: if (entity instanceof Persist) { ((Persist) entity).persist(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; case UPDATE: if (entity instanceof Update) { ((Update) entity).update(); } if (entity instanceof PersistOrUpdate) { ((PersistOrUpdate) entity).persistOrUpdate(); } break; default: break; } } } and here's my Validateable interface that it checks against (the outer interface is just a marker, the inner contain the methods): public interface Validateable { interface Persist extends Validateable { void persist(); } interface PersistOrUpdate extends Validateable { void persistOrUpdate(); } interface Update extends Validateable { void update(); } } All of this works, however I would like to extend this behavior to Embeddable classes. I know two solutions: call the validation method of the embeddable object manually from the entity validation method: public void persistOrUpdate(){ // validate my own properties first // then manually validate the embeddable property: myEmbeddable.persistOrUpdate(); // this works but I'd like something that I don't have to call manually } use reflection, checking all properties to see if their type is of one of their interface types. This would work, but it's not pretty. Is there a more elegant solution?

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• Weird behavior with windows startup C#

  - by FrieK

  Hi, I've created an application with the option to start on Windows startup. First I did this via the Registry, like this: private void RunOnStartup(bool RunOnStartup) { Microsoft.Win32.RegistryKey key = Microsoft.Win32.Registry.CurrentUser.OpenSubKey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true); if (RunOnStartup) { key.SetValue(ProgramTitle, System.Windows.Forms.Application.ExecutablePath.ToString()); } else { key.DeleteValue(ProgramTitle, false); } } And this worked, but not correctly. It started the .exe but with the same behavior as it was a new one with the default 'config.xml' it needs. Which is obviously wrong. I did not manage to find out what was wrong, so I tried it differently: create a shortcut in the Startup folder. Couldn't go wrong I figured, I mean, it's just a shortcut right? I used this code: private void RunOnStartup(bool RunOnStartup) { string startup = Environment.GetFolderPath(Environment.SpecialFolder.Startup) + "\\"+ProgramTitle+".url"; if (RunOnStartup) { using (StreamWriter writer = new StreamWriter(startup)) { string app = System.Reflection.Assembly.GetExecutingAssembly().Location; writer.WriteLine("[InternetShortcut]"); writer.WriteLine("URL=file:///" + app); writer.WriteLine("IconIndex=0"); string icon = app.Replace('\\', '/'); writer.WriteLine("IconFile=" + icon); writer.Flush(); } } else { if (File.Exists(startup)) { File.Delete(startup); } } } And this worked as well, it started, but with the same behavior. So my question is, does anyone have any idea how this happens? Any help is much appreciated! Thanks

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• Approaches for animating a C# property over time?

  - by Mario Fritsch

  I'm currently trying to animate a bunch of public properties on certain objects. Usually they are of type float or vectors of floats (the type is known at compile-time). I want to be able to: assign a static value to them (MyObject.Duration = 10f;) or assign a random value to them by specifying a minimum and maximum value and optionally also a weight (MyObject.Duration = new RandomFloat(5f, 20f, 2f);) or "bind" this property to the property of another object (think of a child object binding some of its properties to its parent object, like its color or size or sth.) or assign sort of a keyframe animation to them, specifying a variable number of keyframes with timecode and the property's value at that specific point in time as well as information about how to interpolate between these frames The keyframes should be able to accept random values for each frame, both for the time and the property's value. What would be a practical approach for this kind of system? Currently I'm thinking about polymorphism: implement a base class or interface with a public Value-property and/or GetValue(float time)-method and then creating different sub classes like StaticValue, RandomValue, BindingValue and AnimatedValue implementing this base class or interface. Doesn't seem very elegant, though, and the initialization of even simple objects becomes a bit tedious. Another idea would be to implement these properties just as regular floats or vectors and create special "Modifier"-types binding to these properties. To retrieve the "real" value of the property, I'd first call any Modifier bound to the property, which would in turn update the actual object's property for me to retrieve later on. That would most likely mean using reflection at some point, which could be quite bad for performance as I'll probably have thousands of properties to update dozens of times per second. Any suggestions on this? Being a novice I'm (hopefully) missing some far more elegant and/or practical solution than I'm already playing around with :( Edit: Probably should have mentioned this earlier, but WPF isn't an option - it's not available on all targetted platforms, so I can't rely on it. I'm aware of its powerful databinding and animation capabilities, but I need to roll my own (or find some other lightweight alternative meeting my needs).

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• When is Googling it wrong?

  - by Drahcir

  I've been going through Stack Overflow for quite a bit now and noticed certain people (usually experienced programmers) frown upon Googling (researching) certain problems. Since I myself tend to use Google quite a bit to solve certain programming related issues I found certain comments rather demoralising. Now some of you may have come here trigger happy to delete this post but I needed some clarification. I usually Google things that usually syntax related that I would have never figured out on my own. For example I once wondered how to access the properties of a class that I didn't have a direct relationship to. So after a bit of research I discovered reflection and got what I wanted. Now in another scenario is learning a new language, in my case Silverlight were it differs in certain aspects of .NET compared to say ASP.NET. A few weeks ago I had no idea how to load another Silverlight page (usercontrol) and had to Google my way to the solution which I found wasn't as simple as I had imagined. In scenario three is were I myself frown up, that is just stealing a huge chunk of code to avoid doing the work yourself, for example paging a HTML table using JavaScript, where one just copies and pastes the JavasSript code without as much as trying to understand how it works. I do admit I have done this once or twice before for trivial tasks that had very little time limit and weren't all that important but most of the time still have to throw away what I found because it took too much time to adapt it and get what I wanted out of it. In the last scenario, I sometimes have a piece of code that I would be really unhappy about, as in I find it sloppy or too overcomplicated and try to look on the Internet to see other ways to tackle the same problem, let's say filtering through a table. With the knowledge I acquire I learned new coding practices that help me work more efficiently like "Do not repeat yourself" and such. Now in your opinion when do you find it wrong to use Google (or any other researching tool) to find a solution to your problem?

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• Is there a way to find out whether a class is a direct base of another class?

  - by user176168

  Hi I'm wondering whether there is a way to find out whether a class is a direct base of another class i.e. in boost type trait terms a is_direct_base_of function. As far as I can see boost doesn't see to support this kind of functionality which leads me to think that its impossible with the current C++ standard. The reason I want it is to do some validation checking on two macro's that are used for a reflection system to specify that one class is derived from another e.g. header.h: #define BASE A #define DERIVED B class A {}; class B : public A { #include <rtti.h> }; rtti.h: // I want to check that the two macro's are correct with a compile time assert Rtti<BASE, DERIVED> m_rtti; Although the macro's seem unnecessary in this simple example in my real world scenario rtti.h is a lot more complex. One possible avenue would be to compare the size of the this pointer with the size of a this pointer cast to the base type and some how trying to figure out whether its the size of the base class itself away or something (yeah your right I don't know how that would work either! lol)

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• Complicated .NET factory design

  - by Tom W

  Hello SO; I'm planning to ask a fairly elaborate question that is also something of a musing here, so bear with me... I'm trying to design a factory implementation for a simulation application. The simulation will consist of different sorts of entities i.e. it is not a homogenous simulation in any respect. As a result, there will be numerous very different concrete implementations and only the very general properties will be abstracted at the top level. What I'd like to be able to do is create new simulation entities by calling a method on the model with a series of named arguments representing the parameters of the entity, and have the model infer what type of object is being described by the inbound parameters (from the names of the parameters and potentially the sequence they occur in) and call a factory method on the appropriate derived class. For example, if I pass the model a pair of parameters (Param1=5000, Param2="Bacon") I would like it to infer that the names Param1 and Param2 'belong' to the class "Blob1" and call a shared function "getBlob1" with named parameters Param1:=5000, Param2:="Bacon" whereas if I pass the model (Param1=5000, Param3=50) it would call a similar factory method for Blob2; because Param1 and Param3 in that order 'belong' to Blob2. I foresee several issues to resolve: Whether or not I can reflect on the available types with string parameter names and how to do this if it's possible Whether or not there's a neat way of doing the appropriate constructor inference from the combinatoric properties of the argument list or whether I'm going to have to bodge something to do it 'by hand'. If possible I'd like the model class to be able to accept parameters as parameters rather than as some collection of keys and values, which would require the model to expose a large number of parametrised methods at runtime without me having to code them explicitly - presumably one for every factory method available in the relevant namespace. What I'm really asking is how you'd go about implementing such a system, rather than whether or not it's fundamentally possible. I don't have the foresight or experience with .NET reflection to be able to figure out a way by myself. Hopefully this will prove an informative discussion.

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• Method not being resolved for dynamic generic type

  - by kelloti

  I have these types: public class GenericDao<T> { public T Save(T t) { return t; } } public abstract class DomainObject { // Some properties protected abstract dynamic Dao { get; } public virtual void Save() { var dao = Dao; dao.Save(this); } } public class Attachment : DomainObject { protected dynamic Dao { get { return new GenericDao<Attachment>(); } } } Then when I run this code it fails with RuntimeBinderException: Best overloaded method match for 'GenericDAO<Attachment.Save(Attachment)' has some invalid arguments var obj = new Attachment() { /* set properties */ }; obj.Save(); I've verified that in DomainObject.Save() "this" is definitely Attachment, so the error doesn't really make sense. Can anyone shed some light on why the method isn't resolving? Some more information - It succeeds if I change the contents of DomainObject.Save() to use reflection: public virtual void Save() { var dao = Dao; var type = dao.GetType(); var save = ((Type)type).GetMethod("Save"); save.Invoke(dao, new []{this}); }

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• Compare Properties automatically

  - by juergen d

  I want to get the names of all properties that changed for matching objects. I have these (simplified) classes: public enum PersonType { Student, Professor, Employee } class Person { public string Name { get; set; } public PersonType Type { get; set; } } class Student : Person { public string MatriculationNumber { get; set; } } class Subject { public string Name { get; set; } public int WeeklyHours { get; set; } } class Professor : Person { public List<Subject> Subjects { get; set; } } Now I want to get the objects where the Property values differ: List<Person> oldPersonList = ... List<Person> newPersonList = ... List<Difference> = GetDifferences(oldPersonList, newPersonList); public List<Difference> GetDifferences(List<Person> oldP, List<Person> newP) { //how to check the properties without casting and checking //for each type and individual property?? //can this be done with Reflection even in Lists?? } In the end I would like to have a list of Differences like this: class Difference { public List<string> ChangedProperties { get; set; } public Person NewPerson { get; set; } public Person OldPerson { get; set; } } The ChangedProperties should contain the name of the changed properties.

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• Does this copy the reference or the object?

  - by Water Cooler v2

  Sorry, I am being both thick and lazy, but mostly lazy. Actually, not even that. I am trying to save time so I can do more in less time as there's a lot to be done. Does this copy the reference or the actual object data? public class Foo { private NameValueCollection _nvc = null; public Foo( NameValueCollection nvc) { _nvc = nvc; } } public class Bar { public static void Main() { NameValueCollection toPass = new NameValueCollection(); new Foo( toPass ); // I believe this only copies the reference // so if I ever wanted to compare toPass and // Foo._nvc (assuming I got hold of the private // field using reflection), I would only have to // compare the references and wouldn't have to compare // each string (deep copy compare), right? } I think I know the answer for sure: it only copies the reference. But I am not even sure why I am asking this. I guess my only concern is, if, after instantiating Foo by calling its parameterized ctor with toPass, if I needed to make sure that the NVC I passed as toPass and the NVC private field _nvc had the exact same content, I would just need to compare their references, right?

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• Reducing Duplicated Code

  - by cam

  I have some code that works on the color structure like this public void ChangeColor() { thisColor.R = thisColor.R + 5; } Now I need to make a method that changes a different variable depending on what it is passed. Here is what the code looks like now. public void ChangeColor(int RGBValue) { switch(RGBValue) { case 1: thisColor.R = thisColor.R + 5; break; case 2: thiscolor.B = thisColor.B + 5; break; } } Now, this is something I would normally never question, I'd just throw a #region statement around it and call it a day, but this is just an example of what I have, the actual function is quite long. I want it to look like this: public void ChangeColor(int RGBValue) { thiscolor.RGBValue = thiscolor.RGBValue; } So essentially the value would refer to the variable being used. Is there a name for this? Is this what Reflection is for? Or something like that... Is there a way to do this?

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• Java program using a class from a JAR file

  - by Myn

  Hi guys, I'll try to phrase this as best I can. I have a program which has an API-like functionality - it uses reflection to dynamically call methods from within a class. In this instance: Server.java public static void main(String[] args) { Class<?> clazz = Class.forName("DiHandler"); StHandler out = (StHandler) clazz; out.read(); DiHandler.java // implements StHandler import edu.ds.*; public void read() { Ds aType = new Ds(); aType = "134"; } So DiHandler has a method read() which can contain anything, it doesn't matter to Server.java after compile time. My problem is: DiHandler.java uses the class Ds from a JAR file. When I'm working on DiHandler.java in Eclipse (in a separate project from the project Server.java is in) I can add this JAR without a problem. But when I move DiHandler.class, after it's compiled, to be used by Server.class, how can it still use the JAR file? I hope this makes some sense, I suppose another way to phrase it would be how can I allow DiHandler to call on a class from the JAR without editing the classpath? Thanks very much in advance and sorry for any confusion or poor phrasing, I can only offer thanks and the customary offer of a pint for any assistance. M

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• How can I [simply] consume JSON Data in a Line of Business Web Application

  - by Atomiton

  I usually use JSON with jQuery to just return a string with html. However, I want to start to use Javascript objects in my code. What's the simplest way to get started using json objects on my page? Here's a sample Ajax call ( after $(document).ready( { ... }) of course: $('#btn').click(function(event) { event.preventDefault(); var out = $('#result'); $.ajax({ url: "CustomerServices.asmx/GetCustomersByInvoiceCount", success: function(msg) { // // Iterate through the json results and spit them out to a page? // }, data: "{ 'invoiceCount' : 100 }" }); }); My WebMethod: [WebMethod(Description="Gets customers with more than n invoices")] public List<Customer> GetCustomersByInvoiceCount(int? invoiceCount) { using (dbDataContext db = new dbDataContext()) { return db.Customers.Where(c => c.InvoiceCount >= invoiceCount); } } What gets returned: {"d":[{"__type":"Customer","Account":"1116317","Name":"SOME COMPANY","Address":"UNit 1 , 392 JOHN ST. ","LastTransaction":"\/Date(1268294400000)\/","HighestBalance":13922.34},{"__type":"Customer","Account":"1116318","Name":"ANOTHER COMPANY","Address":"UNIT #345 , 392 JOHN ST. ","LastTransaction":"\/Date(1265097600000)\/","HighestBalance":549.42}]} What I'd LIKE to know, is what are people generally doing with this returned json? Do you iterate through the properties and create an html table on the fly? Is there way to "bind" JSON data using a javascript version of reflection ( something like the .Net GridView Control ) Do you throw this returned data into a Javascript Object and then do something with it? An example of what I want to achieve is to have an plain ol' html page ( on a mobile device )with a list of a Salesperson's Customers. When one of those customers are clicked, the customer id gets sent to a webservice which retrieves the customer details that are relevant to a sales person. I know the SO talent pool is quite deep so I figured you all here would be able to guide in the right direction and give me a few ideas on the best way to approach this.

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• In maven2, how do I assemble bits and pieces of different modules to create final distributions?

  - by Carcassi

  I have four maven project: client api jar web service war ui jar web interface war The service war will need to be packaged to include the client api jar, together with javadocs (so that each version is distributed with a matching client and documentation). The web interface war will need the ui jar and all the dependencies (webstart/applet deployment). So I need a 5th project that does all the packaging. How to do this with ant or a script is perfectly clear to me, but not in maven. I tried the following: having the javadocs included as part of the war packaging: this requires the execution of the javadocs goal in project 1 before execution of package in project 2. Haven't found a way to bind plugins/goals across different projects. Using the assembly plugin in project2 had the same problem. create a fifth project and use the assembly plugin. Still the same problems as before, with the problem that since I need different pieces from each sub-project I do not understand how this can be done using the assembly. Is this too hard to do in maven, and should I just give up? Or I am looking at it wrong, in which case, how should I be looking at it? Thanks! Upon further reflection, here is a partial answer: Each project should build all its artifacts. This is done by having the plugins configured to run as per the prepare-resources and package phases. So, in my case, I prepare all that needs to be generated (jar, javadocs, xsd documentation, ...) as different artifacts so that a single "package" goal execution creates all. So, it's not "how project 2 forces project 1 to run different goals", but it's "make project 1 create all of its artifact as part as the normal lifecycle). This seems to simplify things.

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• Calculating collission for a moving circle, without overlapping the boundaries

  - by Robert Vella

  Let's say I have circle bouncing around inside a rectangular area. At some point this circle will collide with one of the surfaces of the rectangle and reflect back. The usual way I'd do this would be to let the circle overlap that boundary and then reflect the velocity vector. The fact that the circle actually overlaps the boundary isn't usually a problem, nor really noticeable at low velocity. At high velocity it becomes quite clear that the circle is doing something it shouldn't. What I'd like to do is to programmitically take reflection into account and place the circle at it's proper position before displaying it on the screen. This means that I have to calculate the point where it hits the boundary between it's current position and it's future position -- rather than calculating it's new position and then checking if it has hit the boundary. This is a little bit more complicated than the usual circle/rectangle collission problem. I have a vague idea of how I should do it -- basically create a bounding rectangle between the current position and the new position, which brings up a slew of problems of it's own (Since the rectangle is rotated according to the direction of the circle's velocity). However, I'm thinking that this is a common problem, and that a common solution already exists. Is there a common solution to this kind of problem? Perhaps some basic theories which I should look into?

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• Array Indexing Properties of A Class

  - by Chris

  I have a class that has several properties: class Person { string Name; int Age; DateTime BirthDate; } Then I have a sort of wrapper class with a List<Person>. Within this wrapper class I want to be able to do something like Wrapper["Name"] that returns a new List<string> using .Select(x=>x.Name). How do I create a wrapper class around an IEnumerable that supports mapping a string to the Property name? Something like the pseudo code below, but obviously it doesn't work. I'm 99.9% sure the solution will have to use Reflection and thats fine. class Wrapper { List<Person> PersonList; List<dynamic> this[string Column] { return PersonList.Select(x => x.[Column]).ToList(); } } This may not seem like a good design, but its a fix to eventually enable the correct design from .NET 2.0 days. As I have it right now, the data is stored in Columns, so there is actually a List of Lists within my class right now. Using the above example there would be three ILists (with a string Title) Name, Age, and Birthdate. Everything is currently predicated on addressing the columns by their "string" name. I'm trying to convert the data structure to row based with an IEnumberable interface to allow Linq eventually while still maintaining the functionality of my current code. Is converting the code to a Row based IEnumberable a good idea?

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• eliminating duplicate Enum code

  - by Don

  Hi, I have a large number of Enums that implement this interface: /** * Interface for an enumeration, each element of which can be uniquely identified by it's code */ public interface CodableEnum { /** * Get the element with a particular code * @param code * @return */ public CodableEnum getByCode(String code); /** * Get the code that identifies an element of the enum * @return */ public String getCode(); } A typical example is: public enum IMType implements CodableEnum { MSN_MESSENGER("msn_messenger"), GOOGLE_TALK("google_talk"), SKYPE("skype"), YAHOO_MESSENGER("yahoo_messenger"); private final String code; IMType (String code) { this.code = code; } public String getCode() { return code; } public IMType getByCode(String code) { for (IMType e : IMType.values()) { if (e.getCode().equalsIgnoreCase(code)) { return e; } } } } As you can imagine these methods are virtually identical in all implementations of CodableEnum. I would like to eliminate this duplication, but frankly don't know how. I tried using a class such as the following: public abstract class DefaultCodableEnum implements CodableEnum { private final String code; DefaultCodableEnum(String code) { this.code = code; } public String getCode() { return this.code; } public abstract CodableEnum getByCode(String code); } But this turns out to be fairly useless because: An enum cannot extend a class Elements of an enum (SKYPE, GOOGLE_TALK, etc.) cannot extend a class I cannot provide a default implementation of getByCode(), because DefaultCodableEnum is not itself an Enum. I tried changing DefaultCodableEnum to extend java.lang.Enum, but this doesn't appear to be allowed. Any suggestions that do not rely on reflection? Thanks, Don

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• Fluent NHibernate no data being returned

  - by czuroski

  Hello, I have been successfully using NHibernate, but now I am trying to move to Fluent NHibernate. I have created all of my mapping files and set up my session manager to use a Fluent Configuration. I then run my application and it runs successfully, but no data is returned. There are no errors or any indication that there is a problem, but nothing runs. when using NHibernate, if I don't set my hbm xml files as an embedded resource, this same thing happens. This makes me wonder what I have to set my Map classes to. Right now, they are just set to Compile, and they are compiled into the dll, which I can see by disassembling it. Does anyone have any thoughts as to what may be happening here? Thanks private ISessionFactory GetSessionFactory() { return Fluently.Configure() .Database( IfxOdbcConfiguration .Informix1000 .ConnectionString("Provider=Ifxoledbc.2;Password=mypass;Persist Security Info=True;User ID=myuser;Data Source=mysource") .Dialect<InformixDialect1000>() .ProxyFactoryFactory<ProxyFactoryFactory>() .Driver<OleDbDriver>() .ShowSql() ) .Mappings( m => m.FluentMappings .AddFromAssemblyOf<cmCase>() .AddFromAssemblyOf<attorney>() .AddFromAssemblyOf<creditor>() .AddFromAssemblyOf<party>() .AddFromAssemblyOf<person>() .AddFromAssemblyOf<sardbk>() .AddFromAssemblyOf<schedule>() //x => x.FluentMappings.AddFromAssembly(System.Reflection.Assembly.GetExecutingAssembly()) //.ExportTo("C:\\mappings") ) .BuildSessionFactory(); }

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• How to make 2 incompatible types, but with the same members, interchangeable?

  - by Quigrim

  Yesterday 2 of the guys on our team came to me with an uncommon problem. We are using a third-party component in one of our winforms applications. All the code has already been written against it. They then wanted to incorporate another third-party component, by the same vender, into our application. To their delight they found that the second component had the exact same public members as the first. But to their dismay, the 2 components have completely separate inheritance hierarchies, and implement no common interfaces. Makes you wonder... Well, makes me wonder. An example of the problem: public class ThirdPartyClass1 { public string Name { get { return "ThirdPartyClass1"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass1 is doing its thing."); } } public class ThirdPartyClass2 { public string Name { get { return "ThirdPartyClass2"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass2 is doing its thing."); } } Gladly they felt copying and pasting the code they wrote for the first component was not the correct answer. So they were thinking of assigning the component instant into an object reference and then modifying the code to do conditional casts after checking what type it was. But that is arguably even uglier than the copy and paste approach. So they then asked me if I can write some reflection code to access the properties and call the methods off the two different object types since we know what they are, and they are exactly the same. But my first thought was that there goes the elegance. I figure there has to be a better, graceful solution to this problem.

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• XML Serialization : Has property of type Class1 : Class1 has another property : How to write the property of Class1 into XML?

  - by Wonderlander

  I want to serialize a class. In this class there's a property, type of Class1, while there are other properties in Class1. public abstract class ComponentBase { [ToSerialize]//An attribute defined my me, indicating whether or not to serialize this property. public ComponentArgs Parameters { get; set; } } public class ComponentArgs { public string WorkingPath { get; set; } public IList<Language> Languages { get; set; } public string ComponentOutputPath { get; set; } } The information serialized must be put into a Dictionary, such as ComponentSettings[str_Name]=str_Value. The method used in reading this value is Reflection. pinfo: Property Info got via Type.GetProperties(); componentSettings.Add(pinfo.Name, pinfo.GetValue((object)this, null).ToString()); The information after serialization is: <Parameters>MS.STBIntl.Pippin.Framework.ComponentArgs</Parameters> instead of the value of ComponentArgs.WorkingPath. The solution I thought of is to append to the following line an if judgement: componentSettings.Add(pinfo.Name, pinfo.GetValue((object)this, null).ToString()); if(pinfo is ComponentArgs) componentSettings.Add(pinfo.Name, pinfo.GetValue( (ComponentArgs)this, null).WorkingPath+"\n"+ LanguageList+"\n"+ //Language list is a concatinated string of all elements in the list. (ComponentArgs)this, null).ComponentOutputPath+"\n"+ ); When deserializing, add a judgement of whether the value contains more than 2 "\n", if so, extract each value from the string. But this way seems clumsy and much more like an workaround. I wonder if there's any more professional way of doing it? My reviewer is very particular and he won't accept such a solution. If you know a way, could you please share it with me? Thanks a lot.

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