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  • Converting currencies via intermediate currencies.

    - by chillitom
    class FxRate { string Base { get; set; } string Target { get; set; } double Rate { get; set; } } private IList<FxRate> rates = new List<FxRate> { new FxRate {Base = "EUR", Target = "USD", Rate = 1.3668}, new FxRate {Base = "GBP", Target = "USD", Rate = 1.5039}, new FxRate {Base = "USD", Target = "CHF", Rate = 1.0694}, new FxRate {Base = "CHF", Target = "SEK", Rate = 8.12} // ... }; Given a large yet incomplete list of exchange rates where all currencies appear at least once (either as a target or base currency): What algorithm would I use to be able to derive rates for exchanges that aren't directly listed? I'm looking for a general purpose algorithm of the form: public double Rate(string baseCode, string targetCode, double currency) { return ... } In the example above a derived rate would be GBP-CHF or EUR-SEK (which would require using the conversions for EUR-USD, USD-CHF, CHF-SEK) Whilst I know how to do the conversions by hand I'm looking for a tidy way (perhaps using LINQ) to perform these derived conversions perhaps involving multiple currency hops, what's the nicest way to go about this?

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  • Jquery if statement help

    - by mtwallet
    Hi. I want to know how to correctly write an if statement with jquery. I have a bunch of div's with an anchor in each that when clicked expands the the div's width using toggleClass. This works fine but I want to write an if statement that checks to see if the other div's have the same class applied, if so contract that div, then expand the next div (hope that makes sense), my code so far: HTML: <div class="content-block"> <h2>Title</h2> <p>Content...</p> <a class="expand" href="#">Expand View</a> </div> <div class="content-block"> <h2>Title</h2> <p>Content...</p> <a class="expand" href="#">Expand View</a> </div> <div class="content-block"> <h2>Title</h2> <p>Content...</p> <a class="expand" href="#">Expand View</a> </div> <div class="content-block"> <h2>Title</h2> <p>Content...</p> <a class="expand" href="#">Expand View</a> </div> JQUERY: $(document).ready(function(){ $('a.expand').click(function(){ $(this).parent('.content-block').toggleClass('wide'); }); });

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  • Optional Member Objects

    - by David Relihan
    Okay, so you have a load of methods sprinkled around your systems main class. So you do the right thing and refactor by creating a new class and perform move method(s) into a new class. The new class has a single responsibility and all is right with the world again: class Feature { public: Feature(){}; void doSomething(); void doSomething1(); void doSomething2(); }; So now your original class has a member variable of type object: Feature _feature; Which you will call in the main class. Now if you do this many times, you will have many member-objects in your main class. Now these features may or not be required based on configuration so in a way it's costly having all these objects that may or not be needed. Can anyone suggest a way of improving this? At the moment I plan to test in the newly created class if the feature is enabled - so the when a call is made to method I will return if it is not enabled. I could have a pointer to the object and then only call new if feature is enabled - but this means I will have to test before I call a method on it which would be potentially dangerous and not very readable. Would having an auto_ptr to the object improve things: auto_ptr<Feature> feature; Or am I still paying the cost of object invokation even though the object may\or may not be required. BTW - I don't think this is premeature optimisation - I just want to consider the possibilites.

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  • XPATH Query: How to get two elements?

    - by Damiano
    Hello My HTML code is: <table> <tr> <td class="data1"><p>1</td></td> <td class="data1"><p>2</td></td> <td class="data1"><p>3</td></td> <td class="data1"><p>4</td></td> </tr> <tr> <td class="data1"><p>5</td></td> <td class="data1"><p>6</td></td> <td class="data1"><p>7</td></td> <td class="data1"><p>8</td></td> </tr> </table> My query is: xpath='//tr//td[@class="data1"][4]/p' The results is: <p>4</p> <p>8</p> The results is correct! but, if I want to get example: <p>3</p> <p>4</p> <p>7</p> <p>8</p> So [3]/p and [4]/p How to get these two elements each <tr> ? Thank you so much!

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  • Django error - no module named

    - by Shreyas
    Here is my relevant directory structure (Windows 7, Python 2.7, virtualenv) -userProf - - manage.py - -UserProfile - sampleapp_db - urls.py - views.py - wsgi.py - __init__.py - -libs - - __init__.py - -allauth - - app_settings.py - - models.py - - tests.py - - urls.py - - utils.py - - - -account - - - admin.py - - - context_processors.py - - - models.py - - - urls.py - - - __init__.py - -socialaccount - - - admin.py - - - context_processors.py - - - models.py - - - urls.py - - - views.py - - - __init__.py - - - - -templates - -account - - - base.html - - - email.html -settings - base_settings.py - dev.py - __init__.py - -static -css I get the following error when I try to run this dango app Error: No module named account I have read other posts on SO that refer to the syspath being the issue or that the appname matches the project name Django Shell No module named settings ...as a result of this, I added the following statements in the base_settings.py file import sys base = os.path.abspath(os.path.dirname(os.path.dirname(__file__))) base_parent = os.path.dirname(base) sys.path.append(base) sys.path.append(base_parent) sys.path.append(os.path.join(base,'libs')) sys.path.append(os.path.join(base,'libs','allauth','account')) I verified that the sys.path is correct by putting a break in PyCharm and evaluating sys.path Should I be putting this in manage.py? Some other SO postings referred to not being able to import the module but I can launch the python console and import UserProfile.libs.allauth.account without any exceptions being thrown! My base_setings.py has the following relevant section INSTALLED_APPS = ( 'UserProfile.libs.allauth.account', )

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  • unable to compile a servlet in ubuntu

    - by codeomnitrix
    I am newbie to j2ee. I have download and installed j2eesdk-1_4_03-linux.bin in my ubuntu 10.04 distribution. and then i tried to code my first servlet in it as: import java.io.*; import javax.servelet.*; import javax.servelet.http.*; public class HowdyServelet extends HttpServelet{ public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ PrintWriter out = response.getWriter(); response.setContentType("text/html"); out.println("<html>"); out.println("<head><title>howdy</title></head>"); out.println("<body>"); out.println("<center><h1>Howdy</h1></center>"); out.println("</body>"); out.println("</html>"); } } and here are the environment variables i set after installation: 1. J2EE_HOME=/home/vinit/SUNWappserver 2. JAVA_HOME=/home/vinit/SUNWappserver/jdk 3. CLASSPATH=/home/vinit/SUNWappserver/lib and now i tried to compile the servlet using javac HowdyServelet.java But i got following errors: HowdyServelet.java:2: package javax.servelet does not exist import javax.servelet.*; ^ HowdyServelet.java:3: package javax.servelet.http does not exist import javax.servelet.http.*; ^ HowdyServelet.java:5: cannot find symbol symbol: class HttpServelet public class HowdyServelet extends HttpServelet{ ^ HowdyServelet.java:6: cannot find symbol symbol : class HttpServeletRequest location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ HowdyServelet.java:6: cannot find symbol symbol : class HttpServeletResponse location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ HowdyServelet.java:6: cannot find symbol symbol : class ServeletException location: class HowdyServelet public void doGet(HttpServeletRequest request, HttpServeletResponse response) throws IOException, ServeletException{ ^ 6 errors So how to compile this servlet. Thanks in advance.

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  • How do I get the element after my horizontal css navigation bar to appear below it?

    - by Curyous
    I'm using a css unordered list to make a site navigation bar, using display: inline, display: block, and float: left. The next element that I put after the navigation bar is placed to the right of it. How can I align the next element so that it is displayed below? The html: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd"> <html> <head> <link type="text/css" rel="stylesheet" href="/stylesheets/test.css" /> </head> <body> <div> <ul class="nav"> <li class="nav"><a class="nav" href="#">One1</a></li> <li class="nav"><a class="nav" href="#">Two</a></li> <li class="nav"><a class="nav" href="#">Three</a></li> <li class="nav"><a class="nav" href="#">Four</a></li> </ul> </div> <div><h2>Heading</h2></div> </body> </html> The css: ul.nav, ul li.nav { display: inline; margin: 0px; padding: 0px; } ul.nav { list-style-type: none; } li.nav { display: block; float: left; background-color: red; } a.nav { background-color: green; padding: 10px; margin: 0px; } a:hover.nav { background-color: gray; }

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  • Add additional content to the middle of string from within a method

    - by Sammy T
    I am working with a log file and I have a method which is creating a generic entry in to the log. The generic log entry looks like this: public StringBuilder GetLogMessage(LogEventType logType, object message) { StringBuilder logEntry = new StringBuilder(); logEntry.AppendFormat("DATE={0} ", DateTime.Now.ToString("dd-MMM-yyyy", new CultureInfo(CommonConfig.EnglishCultureCode))); logEntry.AppendFormat("TIME={0} ", DateTime.Now.ToString("HH:mm:ss", new CultureInfo(CommonConfig.EnglishCultureCode))); logEntry.AppendFormat("ERRORNO={0} ", base.RemoteIPAddress.ToString().Replace(".", string.Empty)); logEntry.AppendFormat("IP={0}", base.RemoteIPAddress.ToString()); logEntry.AppendFormat("LANG={0} ", base.Culture.TwoLetterISOLanguageName); logEntry.AppendFormat("PNR={0} ", this.RecordLocator); logEntry.AppendFormat("AGENT={0} ", base.UserAgent); logEntry.AppendFormat("REF={0} ", base.Referrer); logEntry.AppendFormat("SID={0} ", base.CurrentContext.Session.SessionID); logEntry.AppendFormat("LOGTYPE={0} ", logType.ToString() ); logEntry.AppendFormat("MESSAGE={0} ", message); return logEntry; } What would be the best approach for adding additional parameters before "MESSAGE="? For example if I wanted to add "MODULE=" from a derived class when the GetLogMessage is being run. Would a delegate be what I am looking for or marking the method as virtual and overriding it or do I need something entirely different? Any help would be appreciated.

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  • Change classes instantiated with loadNibNamed

    - by Nick H247
    I am trying to change the class of objects created with a nib with the iPhone SDK. The reason for this is; i dont know until runtime what the class is that i want the nib object to be (though they will have the same UIView based super class), and i dont want to create a different nib for every eventuality - as the .nib will be the same for each, apart from the class of one object. I have been successful, with a couple of methods, but either have some knock on effects or am unsure of how safe the methods I have used are: Method 1: Override alloc, on the super class and set a c variable to the class I require: + (id) alloc { if (theClassIWant) { id object = [theClassIWant allocWithZone:NSDefaultMallocZone()]; theClassIWant = nil; return object; } return [BaseClass allocWithZone:NSDefaultMallocZone()]; } this works well, and i assume is 'reasonably' safe, though if I alloc a subclass myself (without setting 'theClassIWant') - an object of the base class is created. I also dont really like the idea of overriding alloc... Method 2: use object_setClass(self,theClassIWant) in initWithCoder (before calling initWithCoder on the super class): - (id) initWithCoder:(NSCoder *)aDecoder { if (theClassIWant) { // the framework doesn't like this: //[self release]; //self = [theClassIWant alloc]; // whoa now! object_setClass(self,theClassIWant); theClassIWant = nil; return [self initWithCoder:aDecoder]; } if (self = [super initWithCoder:aDecoder]) { ... this also works well, but not all the subclasses are necessarily going to be the same size as the super class, so this could be very unsafe! To combat this i tried releasing and re-allocing to the correct type within initWithCoder, but i got the following error from the framework: "This coder requires that replaced objects be returned from initWithCoder:" dont quite get what this means! i am replacing an object in initWithCoder... Any comments on the validity of these methods, or suggestions of improvements or alternatives welcome!

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  • background image not showing in html

    - by Registered User
    I am having following css <!DOCTYPE html > <html> <head> <meta charset="utf-8"> <title>Black Goose Bistro Summer Menu</title> <link href='http://fonts.googleapis.com/css?family=Marko+One' rel='stylesheet' type='text/css'> <style> body { font-family: Georgia, serif; font-size: 100%; line-height: 175%; margin: 0 15% 0; background-image:url(images/bullseye.png); } #header { margin-top: 0; padding: 3em 1em 2em 1em; text-align: center; } a { text-decoration: none; } h1 { font: bold 1.5em Georgia, serif; text-shadow: .1em .1em .2em gray; } h2 { font-size: 1em; text-transform: uppercase; letter-spacing: .5em; text-align: center; } dt { font-weight: bold; } strong { font-style: italic; } ul { list-style-type: none; margin: 0; padding: 0; } #info p { font-style: italic; } .price { font-family: Georgia, serif; font-style: italic; } p.warning, sup { font-size: small; } .label { font-weight: bold; font-variant: small-caps; font-style: normal; } h2 + p { text-align: center; font-style: italic; } ); </style> </head> <body> <div id="header"> <h1>Black Goose Bistro &bull; Summer Menu</h1> <div id="info"> <p>Baker's Corner, Seekonk, Massachusetts<br> <span class="label">Hours: Monday through Thursday:</span> 11 to 9, <span class="label">Friday and Saturday;</span> 11 to midnight</p> <ul> <li><a href="#appetizers">Appetizers</a></li> <li><a href="#entrees">Main Courses</a></li> <li><a href="#toast">Traditional Toasts</a></li> <li><a href="#dessert">Dessert Selection</a></li> </ul> </div> </div> <div id="appetizers"> <h2>Appetizers</h2> <p>This season, we explore the spicy flavors of the southwest in our appetizer collection.</p> <dl> <dt>Black bean purses</dt> <dd>Spicy black bean and a blend of mexican cheeses wrapped in sheets of phyllo and baked until golden. <span class="price">$3.95</span></dd> <dt class="newitem">Southwestern napoleons with lump crab &mdash; <strong>new item!</strong></dt> <dd>Layers of light lump crab meat, bean and corn salsa, and our handmade flour tortillas. <span class="price">$7.95</span></dd> </dl> </div> <div id="entrees"> <h2>Main courses</h2> <p>Big, bold flavors are the name of the game this summer. Allow us to assist you with finding the perfect wine.</p> <dl> <dt class="newitem">Jerk rotisserie chicken with fried plantains &mdash; <strong>new item!</strong></dt> <dd>Tender chicken slow-roasted on the rotisserie, flavored with spicy and fragrant jerk sauce and served with fried plantains and fresh mango. <strong>Very spicy.</strong> <span class="price">$12.95</span></dd> <dt>Shrimp sate kebabs with peanut sauce</dt> <dd>Skewers of shrimp marinated in lemongrass, garlic, and fish sauce then grilled to perfection. Served with spicy peanut sauce and jasmine rice. <span class="price">$12.95</span></dd> <dt>Grilled skirt steak with mushroom fricasee</dt> <dd>Flavorful skirt steak marinated in asian flavors grilled as you like it<sup>*</sup>. Served over a blend of sauteed wild mushrooms with a side of blue cheese mashed potatoes. <span class="price">$16.95</span></dd> </dl> </div> <div id="toast"> <h2>Traditional Toasts</h2> <p>The ultimate comfort food, our traditional toast recipes are adapted from <a href="http://www.gutenberg.org/files/13923/13923-h/13923-h.htm"><cite>The Whitehouse Cookbook</cite></a> published in 1887.</p> <dl> <dt>Cream toast</dt> <dd>Simple cream sauce over highest quality toasted bread, baked daily. <span class="price">$3.95</span></dd> <dt>Mushroom toast</dt> <dd>Layers of light lump crab meat, bean and corn salsa, and our handmade flour tortillas. <span class="price">$6.95</span></dd> <dt>Nun's toast</dt> <dd>Onions and hard-boiled eggs in a cream sauce over buttered hot toast. <span class="price">$6.95</span></dd> <dt>Apple toast</dt> <dd>Sweet, cinnamon stewed apples over delicious buttery grilled bread. <span class="price">$6.95</span></dd> </dl> </div> <div id="dessert"> <h2>Dessert Selection</h2> <p>Be sure to save room for our desserts, made daily by our own <a href="http://www.jwu.edu/college.aspx?id=19510">Johnson & Wales</a> trained pastry chef.</p> <dl> <dt class="newitem">Lemon chiffon cake &mdash; <strong>new item!</strong></dt> <dd>Light and citrus flavored sponge cake with buttercream frosting as light as a cloud. <span class="price">$2.95</span></dd> <dt class="newitem">Molten chocolate cake</dt> <dd>Bubba's special dark chocolate cake with a warm, molten center. Served with or without a splash of almond liqueur. <span class="price">$3.95</span></dd> </dl> </div> <p class="warning"><sup>*</sup> We are required to warn you that undercooked food is a health risk.</p> </body> </html> but the background image does not appear in body tag you can see background-image:url(images/bullseye.png); this html page is bistro.html and the directory in which it is contained there is a folder images and inside images folder I have a file bullseye.png .I expect the png to appear in background.But that does not happen. For sake of question I am posting the image here also Let me know if the syntax of css wrong? following is image http://i.stack.imgur.com/YUKgg.png

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  • Is there a way to automaticly call all versions of an inherited method?

    - by Eric
    I'm writing a plug-in for a 3D modeling program. I have a custom class that wraps instances of elements in the 3D model, and in turn derives it's properties from the element it wraps. When the element in the model changes I want my class(es) to update their properties based on the new geometry. In the simplified example below. I have classes AbsCurveBasd, Extrusion, and Shell which are all derived from one another. Each of these classes implement a RefreshFromBaseShape() method which updates specific properties based on the current baseShape the class is wrapping. I can call base.RefreshFromBaseShape() in each implementation of RefreshFromBaseShape() to ensure that all the properties are updated. But I'm wondering if there is a better way where I don't have to remember to do this in every implementation of RefershFromBaseShape()? For example because AbsCurveBased does not have a parameterless constructor the code wont even compile unless the constructors call the base class constructors. public abstract class AbsCurveBased { internal Curve baseShape; double Area{get;set;} public AbsCurveBased(Curve baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public virtual void RefreshFromBaseShape() { //sets the Area property from the baseShape } } public class Extrusion : AbsCurveBased { double Volume{get;set;} double Height{get;set;} public Extrusion(Curve baseShape):base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public override void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets the Volume property based on the area and the height } } public class Shell : Extrusion { double ShellVolume{get;set;} double ShellThickness{get;set;} public Shell(Curve baseShape): base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets this Shell Volume from the Extrusion properties and ShellThickness property } }

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  • Passing IDisposable objects through constructor chains

    - by Matt Enright
    I've got a small hierarchy of objects that in general gets constructed from data in a Stream, but for some particular subclasses, can be synthesized from a simpler argument list. In chaining the constructors from the subclasses, I'm running into an issue with ensuring the disposal of the synthesized stream that the base class constructor needs. Its not escaped me that the use of IDisposable objects this way is possibly just dirty pool (plz advise?) for reasons I've not considered, but, this issue aside, it seems fairly straightforward (and good encapsulation). Codes: abstract class Node { protected Node (Stream raw) { // calculate/generate some base class properties } } class FilesystemNode : Node { public FilesystemNode (FileStream fs) : base (fs) { // all good here; disposing of fs not our responsibility } } class CompositeNode : Node { public CompositeNode (IEnumerable some_stuff) : base (GenerateRaw (some_stuff)) { // rogue stream from GenerateRaw now loose in the wild! } static Stream GenerateRaw (IEnumerable some_stuff) { var content = new MemoryStream (); // molest elements of some_stuff into proper format, write to stream content.Seek (0, SeekOrigin.Begin); return content; } } I realize that not disposing of a MemoryStream is not exactly a world-stopping case of bad CLR citizenship, but it still gives me the heebie-jeebies (not to mention that I may not always be using a MemoryStream for other subtypes). It's not in scope, so I can't explicitly Dispose () it later in the constructor, and adding a using statement in GenerateRaw () is self-defeating since I need the stream returned. Is there a better way to do this? Preemptive strikes: yes, the properties calculated in the Node constructor should be part of the base class, and should not be calculated by (or accessible in) the subclasses I won't require that a stream be passed into CompositeNode (its format should be irrelevant to the caller) The previous iteration had the value calculation in the base class as a separate protected method, which I then just called at the end of each subtype constructor, moved the body of GenerateRaw () into a using statement in the body of the CompositeNode constructor. But the repetition of requiring that call for each constructor and not being able to guarantee that it be run for every subtype ever (a Node is not a Node, semantically, without these properties initialized) gave me heebie-jeebies far worse than the (potential) resource leak here does.

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  • Add delay and focus for a dead simple accordion jquery

    - by kuswantin
    I found the code somewhere in the world, and due to its dead simple nature, I found some things in need to fix, like when hovering the trigger, the content is jumping up down before it settled. I have tried to change the trigger from the title of the accordion block to the whole accordion block to no use. I need help to add a delay and only do the accordion when the cursor is focus in the block. I have corrected my css to make sure the block is covering the hidden part as well when toggled. Here is my latest modified code: var acTrig = ".accordion .title"; $(acTrig).hover(function() { $(".accordion .content").slideUp("normal"); $(this).next(".content").slideDown("normal"); }); $(acTrig).next(".content").hide(); $(acTrig).next(".content").eq(0).css('display', 'block'); This is the HTML: <div class="accordion clearfix"> <div class="title">some Title 1</div> <div class="content"> some content blah </div> </div> <div class="accordion clearfix"> <div class="title">some Title 2</div> <div class="content"> some content blah </div> </div> <div class="accordion clearfix"> <div class="title">some Title 3</div> <div class="content"> some content blah </div> </div> I think I need a way to stop event bubbling somewhere around the code, but can't get it right. Any help would be very much appreciated. Thanks as always.

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  • Too many open files in one of my java routine.

    - by Irfan Zulfiqar
    I have a multithreaded code that has to generated a set of objects and write them to a file. When I run it I sometime get "Too many open files" message in Exception. I have checked the code to make sure that all the file streams are being closed properly. Here is the stack trace. When I do ulimit -a, open files allowed is set to 1024. We think increasing this number is not a viable option / solution. [java] java.io.FileNotFoundException: /export/event_1_0.dtd (Too many open files) [java] at java.io.FileInputStream.open(Native Method) [java] at java.io.FileInputStream.<init>(FileInputStream.java:106) [java] at java.io.FileInputStream.<init>(FileInputStream.java:66) [java] at sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java:70) [java] at sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnection.java:161) [java] at java.net.URL.openStream(URL.java:1010) Now what we have identified so far by looking closely at the list of open files is that the VM is opening same class file multiple times. /export/BaseEvent.class 236 /export/EventType1BaseEvent.class 60 /export/EventType2BaseEvent.class 48 /export/EventType2.class 30 /export/EventType1.class 14 Where BaseEvent is partent of all the classes and EventType1 ant EventType2 inherits EventType1BaseEvent and EventType2BaseEvent respectively. Why would a class loader load the same class file 200+ times. It seems it is opening up the base class as many time it create any child instance. Is this normal? Can it be handler any other way apart from increasing the number of open files?

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  • Is this a safe/valid hash method implementation?

    - by Sean
    I have a set of classes to represent some objects loaded from a database. There are a couple variations of these objects, so I have a common base class and two subclasses to represent the differences. One of the key fields they have in common is an id field. Unfortunately, the id of an object is not unique across all variations, but within a single variation. What I mean is, a single object of type A could have an id between, say, 0 and 1,000,000. An object of type B could have an id between, 25,000 and 1,025,000. This means there's some overlap of id numbers. The objects are just variations of the same kind of thing, though, so I want to think of them as such in my code. (They were assigned ids from different sets for legacy reasons.) So I have classes like this: @class BaseClass @class TypeAClass : BaseClass @class TypeBClass : BaseClass BaseClass has a method (NSNumber *)objectId. However instances of TypeA and TypeB could have overlapping ids as discussed above, so when it comes to equality and putting these into sets, I cannot just use the id alone to check it. The unique key of these instances is, essentially, (class + objectId). So I figured that I could do this by making the following hash function on the BaseClass: -(NSUInteger)hash { return (NSUInteger)[self class] ^ [self.objectId hash]; } I also implemented isEqual like so: - (BOOL)isEqual:(id)object { return (self == object) || ([object class] == [self class] && [self.objectId isEqual:[object objectId]]); } This seems to be working, but I guess I'm just asking here to make sure I'm not overlooking something - especially with the generation of the hash by using the class pointer in that way. Is this safe or is there a better way to do this?

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  • NullPointerException with static variables

    - by tomekK
    I just hit very strange (to me) behaviour of java. I have following classes: public abstract class Unit { public static final Unit KM = KMUnit.INSTANCE; public static final Unit METERS = MeterUnit.INSTANCE; protected Unit() { } public abstract double getValueInUnit(double value, Unit unit); protected abstract double getValueInMeters(double value); } And: public class KMUnit extends Unit { public static final Unit INSTANCE = new KMUnit(); private KMUnit() { } //here are abstract methods overriden } public class MeterUnit extends Unit { public static final Unit INSTANCE = new MeterUnit(); private MeterUnit() { } ///abstract methods overriden } And my test case: public class TestMetricUnits extends TestCase { @Test public void testConversion() { System.out.println("Unit.METERS: " + Unit.METERS); System.out.println("Unit.KM: " + Unit.KM); double meters = Unit.KM.getValueInUnit(102.11, Unit.METERS); assertEquals(0.10211, meters, 0.00001); } } 1) MKUnit and MeterUnit are both singletons initialized statically, so during class loading. Constructors are private, so they can't be initialized anywhere else. 2) Unit class contains static final references to MKUnit.INSTANCE and MeterUnit.INSTANCE I would expect that: KMUnit class is loaded and instance is created. MeterUnit class is loaded and instance is created. Unit class is loaded and both KM and METERS variable are initialized, they are final so they cant be changed. But when I run my test case in console with maven my result is: T E S T S Running de.audi.echargingstations.tests.TestMetricUnits Unit.METERS: m Unit.KM: null Tests run: 3, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.089 sec <<< FAILURE! - in de.audi.echargingstations.tests.TestMetricUnits testConversion(de.audi.echargingstations.tests.TestMetricUnits) Time elapsed: 0.011 sec <<< ERROR! java.lang.NullPointerException: null at de.audi.echargingstations.tests.TestMetricUnits.testConversion(TestMetricUnits.java:29) Results : Tests in error: TestMetricUnits.testConversion:29 NullPointer And the funny part is that, when I run this test from eclipse via JUnit runner everything is fine, I have no NullPointerException and in console I have: Unit.METERS: m Unit.KM: km So the question is: what can be the reason that KM variable in Unit is null (and in the same time METERS is not null)

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  • Plot vectors with labels in matlab

    - by mad
    I have a Nx62 matrix with N 62-D vectors and a NX1 vector with the labels for the vectors. I am trying to plot these vectors with their labels because I want to see the behavior of these classes when plotted in a 62-dimensional space. The vectors belong to three classes according to the labels of a NX1 vector cited before. How to to that in matlab? when i do plot(vector,classes) the result is very weird to analyse, how to put labels in the graph? The code i am using to get the labels, vectors and plotting is the following: %labels is a vector with labels, vectors is a matrix where each line is a vector [labels,vectors]=libsvmread('features-im1.txt'); when I plot a three dimensional vector is simple a=[1,2,3] plot(a) and then I get the result but now i have a set of vectors and a set of labels, and i want to see the distribution of them, i want to plot each of these labels but also want to identify their classes. How to do that in matlab? EDIT: This code is almost working. The problem is the fact that for each vector and class the plot will assign a color. I just want three colors and three labels, one per class. [class,vector]=libsvmread('features-im1.txt'); %the plot doesn't allow negative and 0 values in the label class=class+2; labels = {'class -1','class 0','class 1'}; h = plot(vector); legend(h,labels{class})

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  • Can I flow divs down the page instead of across it?

    - by Brabster
    If I have a collection of div elements, I can use CSS to have them flow across the page and overflow onto the next line. Here's a simple example: <html> <head> <title>Flowing Divs</title> <style type="text/css"> .flow { float: left; margin: 4em 8em; } </style> </head> <body> <div class="container"> <div class="flow">Div 1</div> <div class="flow">Div 2</div> <div class="flow">Div 3</div> <div class="flow">Div 4</div> <div class="flow">Div 5</div> <div class="flow">Div 6</div> <div class="flow">Div 7</div> <div class="flow">Div 8</div> </div> </body> </html> Is it possible to have the divs flow down the page instead of across it, so that they would flow down columns not along lines, but still occupy the same space as they would if they flowed across? So for the example above, if they flowed into two lines of four divs, could I get the first column to contain Div1 and Div2 instead of Div1 and Div5?

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  • How best to calculate derived currency rate conversions using C#/LINQ?

    - by chillitom
    class FxRate { string Base { get; set; } string Target { get; set; } double Rate { get; set; } } private IList<FxRate> rates = new List<FxRate> { new FxRate {Base = "EUR", Target = "USD", Rate = 1.3668}, new FxRate {Base = "GBP", Target = "USD", Rate = 1.5039}, new FxRate {Base = "USD", Target = "CHF", Rate = 1.0694}, new FxRate {Base = "CHF", Target = "SEK", Rate = 8.12} // ... }; Given a large yet incomplete list of exchange rates where all currencies appear at least once (either as a target or base currency): What algorithm would I use to be able to derive rates for exchanges that aren't directly listed? I'm looking for a general purpose algorithm of the form: public double Rate(string baseCode, string targetCode, double currency) { return ... } In the example above a derived rate would be GBP-CHF or EUR-SEK (which would require using the conversions for EUR-USD, USD-CHF, CHF-SEK) Whilst I know how to do the conversions by hand I'm looking for a tidy way (perhaps using LINQ) to perform these derived conversions perhaps involving multiple currency hops, what's the nicest way to go about this?

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  • looping through JSON array

    - by Phil Jackson
    Hi all. I have recently posted another question which straight away users pointed me in the right direction. $.ajax({ type: 'POST', url: './', data: 'token=' + token + '&re=8', cache: false, timeout: 5000, success: function(html){ auth(html); var JSON_array = eval(html); alert(JSON_array[0].username); } }); this returns the data correctly but I want to perform a kind of 'foreach'. the array contains data about multiple incoming and outgoing Instant Messages. So if a user is talking to more than one person at a time i need to loop through. the array's structure is as follows. Array ( [0] => Array ( [username] => Emmalene [contents] => <ul><li class="name">ACTwebDesigns</li><li class="speech">helllllllo</li></ul> <ul><li class="name">ACTwebDesigns</li><li class="speech">sds</li></ul> <ul><li class="name">ACTwebDesigns</li><li class="speech">Sponge</li><li class="speech">dick</li></ul> <ul><li class="name">ACTwebDesigns</li><li class="speech">arghh</li></ul> ) ) any help very much appreciated.

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  • How to model has_many with polymorphism?

    - by Daniel Abrahamsson
    I've run into a situation that I am not quite sure how to model. Suppose I have a User class, and a user has many services. However, these services are quite different, for example a MailService and a BackupService, so single table inheritance won't do. Instead, I am thinking of using polymorphic associations together with an abstract base class: class User < ActiveRecord::Base has_many :services end class Service < ActiveRecord::Base validates_presence_of :user_id, :implementation_id, :implementation_type belongs_to :user belongs_to :implementation, :polymorphic = true delegate :common_service_method, :name, :to => :implementation end #Base class for service implementations class ServiceImplementation < ActiveRecord::Base validates_presence_of :user_id, :on => :create has_one :service, :as => :implementation has_one :user, :through => :service after_create :create_service_record #Tell Rails this class does not use a table. def self.abstract_class? true end #Default name implementation. def name self.class.name end protected #Sets up a service object def create_service_record service = Service.new(:user_id => user_id) service.implementation = self service.save! end end class MailService < ServiceImplementation #validations, etc... def common_service_method puts "MailService implementation of common service method" end end #Example usage MailService.create(..., :user_id => user.id) BackupService.create(...., :user_id => user.id) user.services.each do |s| puts "#{user.name} is using #{s.name}" end #Daniel is using MailService, Daniel is using BackupService So, is this the best solution? Or even a good one? How have you solved this kind of problem?

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  • RoR - howto convert some HTML-elements with css to Rails

    - by NicoJuicy
    I have old HTML code with html and css.. <form action="login" method="post"> <div class="field"> <label for="username">Username</label> <input type="text" class="text" id="username" name="username" value="just click login !"/> </div> <span class="fright"> <button class="button" type="submit"><strong>Log In</strong></button> </span> </div> How can i convert this code to decent rails code? I came up with this, but it ain't right :-( : <% form_for :user, @user, :url => { :action => "login" } do |f| %> <% div_for f, :class => "field text" do %> <%= f.text_field :username %> <%= f.password_field :password, :class => "field text" %> <% end %> <span class="fright"> <%= submit_tag '<strong>Inloggen</strong>', :class => "button",:disable_with => 'verwerken...' %></span> <% end %> I'm having problems with the <strong>Inloggen</strong> And with the <% div_for f, :class => "field text" do %>

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  • JPA 2.0 Provider Hibernate

    - by Rooh
    I have very strange problem we are using jpa 2.0 with hibernate annotations based Database generated through JPA DDL is true and MySQL as Database; i will provide some reference classes and then my porblem. @MappedSuperclass public abstract class Common implements serializable{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", updatable = false) private Long id; @ManyToOne @JoinColumn private Address address; //with all getter and setters //as well equal and hashCode } @Entity public class Parent extends Common{ private String name; @OneToMany(cascade = {CascadeType.MERGE,CascadeType.PERSIST}, mappedBy = "parent") private List<Child> child; //setters and rest of class } @Entity public class Child extends Common{ //some properties with getter/setters } @Entity public class Address implements Serializable{ @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "id", updatable = false) private Long id; private String street; //rest of class with get/setter } as in code you can see that parents and child classes extends Common class so both have address property and id , the problem occurs when change the address refference in parent class it reflect same change in all child objects in list and if change address refference in child class then on merge it will change address refference of parent as well i am not able to figure out is it is problem of jpa or hibernate

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  • Mapping an instance of IList in NHibernate

    - by Martin Kirsche
    I'm trying to map a parent-child relationship using NHibernate (2.1.2), MySql.Data (6.2.2) and MySQL Server (5.1). I figured out that this must be done using a <bag> in the mapping file. I build a test app which is running without yielding any errors and is doing an insert for each entry but somehow the foreign key inside the children table (ParentId) is always empty (null). Here are the important parts of my code... Parent public class Parent { public virtual int Id { get; set; } public virtual IList<Child> Children { get; set; } } <class name="Parent"> <id name="Id"> <generator class="native"/> </id> <bag name="Children" cascade="all"> <key column="ParentId"/> <one-to-many class="Child"/> </bag> </class> Child public class Child { public virtual int Id { get; set; } } <class name="Child"> <id name="Id"> <generator class="native"/> </id> </class> Program using (ISession session = sessionFactory.OpenSession()) { session.Save( new Parent() { Children = new List<Child>() { new Child(), new Child() } }); } Any ideas what I did wrong?

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  • How to add divs inside a div using jquery

    - by Neal
    Hi, I am trying to insert a div inside another div using add() of jquery but it is not working " <div class="portlet" id="panel1"> <div class="portlet-header">1.Feeds</div> <div class="portlet-content">Lorem ipsum dolor sit amet, consectetuer adipiscing elit</div> </div> <div class="portlet" id="panel2"> <div class="portlet-header">2.News</div> <div class="portlet-content">Lorem ipsum dolor sit amet, consectetuer adipiscing elit</div> </div> " " <div class="portlet" id="panel3"> <div class="portlet-header">3.Shopping</div> <div class="portlet-content">Lorem ipsum dolor sit amet, consectetuer adipiscing elit</div> </div> " Actually panel1 and panel2 are inside a div, and panel3 is inside another div.I want to remove panel3 from its div and place it between panel1 and panel2 in their div.

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