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  • Deleting objects with FK constraints in Spring/Hibernate

    - by maxdj
    This seems like such a simple scenario to me, yet I cannot for the life of my find a solution online or in print. I have several objects like so (trimmed down): @Entity public class Group extends BaseObject implements Identifiable<Long> { private Long id; private String name; private Set<HiringManager> managers = new HashSet<HiringManager>(); private List<JobOpening> jobs; @ManyToMany(fetch=FetchType.EAGER) @JoinTable( name="group_hiringManager", joinColumns=@JoinColumn(name="group_id"), inverseJoinColumns=@JoinColumn(name="hiringManager_id") ) public Set<HiringManager> getManagers() { return managers; } @OneToMany(mappedBy="group", fetch=FetchType.EAGER) public List<JobOpening> getJobs() { return jobs; } } @Entity public class JobOpening extends BaseObject implements Identifiable<Long> { private Long id; private String name; private Group group; @ManyToOne @JoinColumn(name="group_id", updatable=false, nullable=true) public Group getGroup() { return group; } } @Entity public class HiringManager extends User { @ManyToMany(mappedBy="managers", fetch=FetchType.EAGER) public Set<Group> getGroups() { return groups; } } Say I want to delete a Group object. Now there are dependencies on it in the JobOpening table and in the group_hiringManager table, which cause the delete function to fail. I don't want to cascade the delete, because the managers have other groups, and the jobopenings can be groupless. I have tried overriding the remove() function of my GroupManager to remove the dependencies, but it seems like no matter what I do they persist, and the delete fails! What is the right way to remove this object?

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  • Entity Framework - refresh objects from database

    - by Nebo
    I'm having trouble with refreshing objects in my database. I have an two PC's and two applications. On the first PC, there's an application which communicates with my database and adds some data to Measurements table. On my other PC, there's an application which retrives the latest Measurement under a timer, so it should retrive measurements added by the application on my first PC too. The problem is it doesn't. On my application start, it caches all the data from database and never get new data added. I use Refresh() method which works well when I change any of the cached data, but it doesn't refresh newly added data. Here is my method which should update the data: public static Entities myEntities = new Entities(); public static Measurement GetLastMeasurement(int conditionId) { myEntities.Refresh(RefreshMode.StoreWins, myEntities.Measurements); return (from measurement in myEntities.Measurements where measurement.ConditionId == conditionId select measurement).OrderByDescending(cd => cd.Timestamp).First(); } P.S. Applications have different connection strings in app.config (different accounts for the same DB).

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  • Setting spring bean property value using ref-bean

    - by Apache Fan
    Hi, I am trying to set a property value using spring. <bean id="velocityPropsBean" class="com.test.CustomProperties" abstract="false" singleton="true" lazy-init="false" autowire="default" dependency-check="default"> <property name="properties"> <props> <prop key="resource.loader">file</prop> <prop key="file.resource.loader.cache">true</prop> <prop key="file.resource.loader.class">org.apache.velocity.runtime.resource.loader.FileResourceLoader</prop> <prop key="file.resource.loader.path">NEED TO INSERT VALUE AT STARTUP</prop> </props> </property> </bean> <bean id="velocityResourcePath" class="java.lang.String" factory-bean="velocityHelper" factory-method="getLoaderPath"/> Now what i need to do is insert the result from getLoaderPath into file.resource.loader.path. The value of getLoaderPath changes so it has to be loaded at server startup. Any thoughts how i can inset the velocityResourcePath value to the property?

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  • Given 4 objects, how to figure out whether exactly 2 have a certain property

    - by Cocorico
    Hi guys! I have another question on how to make most elegant solution to this problem, since I cannot afford to go to computer school right so my actual "pure programming" CS knowledge is not perfect or great. This is basically an algorhythm problem (someone please correct me if I am using that wrong, since I don't want to keep saying them and embarass myself) I have 4 objects. Each of them has an species property that can either be a dog, cat, pig or monkey. So a sample situation could be: object1.species=pig object2.species=cat object3.species=pig object4.species=dog Now, if I want to figure out if all 4 are the same species, I know I could just say: if ( (object1.species==object2.species) && (object2.species==object3.species) && (object3.species==object4.species) ) { // They are all the same animal (don't care WHICH animal they are) } But that isn't so elegant right? And if I suddenly want to know if EXACTLY 3 or 2 of them are the same species (don't care WHICH species it is though), suddenly I'm in spaghetti code. I am using Objective C although I don't know if that matters really, since the most elegant solution to this is I assume the same in all languages conceptually? Anyone got good idea? Thanks!!

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  • Redeclared javascript global variable overrides old value in IE

    - by Yousuf Haider
    (creating a separate question after comments on this: http://stackoverflow.com/questions/2634410/javascript-redeclared-global-variable-overrides-old-value) I am creating a globally scoped variable using the square bracket notation and assigning it a value inside an external js file. In another js file I declare a var with the same name as the one I just created above. Note I am not assigning a value. Since this is a redeclaration of the same variable the old value should not be overriden as described here: http://www.w3schools.com/js/js_variables.asp Create 2 javascript files with the following content : Script1 //create global variable with square bracket notation window['y'] = 'old'; Script2 //redeclaration of the same variable var y; if (!y) y = 'new'; alert(y); //shows New instead of Old in IE Include these 2 files in your html file <html> <head></head> <body> <script type="text/javascript" src="my.js"></script> <script type="text/javascript" src="my2.js"></script> </body> </html> Opening this page in Firefox and Chrome alerts 'old' which is the expected behavior. However in IE 8 the page will actually alert 'new' Any ideas on why this happens on IE ?

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  • binding nested json object value to a form field

    - by Jack
    I am building a dynamic form to edit data in a json object. First, if something like this exists let me know. I would rather not build it but I have searched many times for a tool and have found only tree like structures that require entering quotes. I would be happy to treat all values as strings. This edit functionality is for end users so it needs to be easy an not intimidating. So far I have code that generates nested tables to represent a json object. For each value I display a form field. I would like to bind the form field to the associated nested json value. If I could store a reference to the json value I would build an array of references to each value in a json object tree. I have not found a way to do that with javascript. My last resort approach will be to traverse the table after edits are made. I would rather have dynamic updates but a single submit would be better than nothing. Any ideas? // the json in files nests only a few levels. Here is the format of a simple case, { "researcherid_id":{ "id_key":"researcherid_id", "description":"Use to retrieve bibliometric data", "url_template" :[ { "name": "Author Detail", "url": "http://www.researcherid.com/rid/${key}" } ] } } $.get('file.json',make_json_form); function make_json_form(response) { dataset = $.secureEvalJSON(response); // iterate through the object and generate form field for string values. } // Then after the form is edited I want to display the raw updated json (then I want to save it but that is for another thread) // now I iterate through the form and construct the json object // I would rather have the dataset object var updated on focus out after each edit. function show_json(form_id){ var r = {}; var el = document.getElementById(form_id); table_to_json(r,el,null); $('body').html(formattedJSON(r)); }

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  • Looking for detailed explanation of Hibernate UserType methods for mutable objects

    - by Tom
    I am creating a custom UserType class in Hibernate. The specific case is for an HL7v3 clinical document (I work in health IT). It is a mutable object and most of the documentation around the Hibernate UserType interface seems to center around immutable types. I want a better understanding of how and when the interface methods are used, specifically: assemble - why two parameters (one Serializable, one Object)? What is the use case for this method? disassemble - should I just implement this method to return a serializable form (e.g. String representation)? When and how is this method invoked? equals - is this for update? read? contention? dirty reads? What are the consequences of simply returning false in most cases? replace - I really don't understand where the three Object parameters come from, when this method is invoked, and what Hibernate expects to return, or how that return value is used. Any pointers would be appreciated. I've searched and read all I can find on the subject, but have not found much documentation at all explaining how these methods are used for mutable objects.

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  • Entity Framework and differences between Contains between SQL and objects using ToLower

    - by John Ptacek
    I have run into an "issue" I am not quite sure I understand with Entity Framework. I am using Entity Framework 4 and have tried to utilize a TDD approach. As a result, I recently implemented a search feature using a Repository pattern. For my test project, I am implementing my repository interface and have a set of "fake" object data I am using for test purposes. I ran into an issue trying to get the Contains clause to work for case invariant search. My code snippet for both my test and the repository class used against the database is as follows: if (!string.IsNullOrEmpty(Description)) { items = items.Where(r => r.Description.ToLower().Contains(Description.ToLower())); } However, when I ran my test cases the results where not populated if my case did not match the underlying data. I tried looking into what I thought was an issue for a while. To clear my mind, I went for a run and wondered if the same code with EF would work against a SQL back end database, since SQL will explicitly support the like command and it executed as I expected, using the same logic. I understand why EF against the database back end supports the Contains clause. However, I was surprised that my unit tests did not. Any ideas why other than the SQL server support of the like clause when I use objects I populate in a collection instead of against the database server? Thanks! John

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  • Use continue or Checked Exceptions when checking and processing objects

    - by Johan Pelgrim
    I'm processing, let's say a list of "Document" objects. Before I record the processing of the document successful I first want to check a couple of things. Let's say, the file referring to the document should be present and something in the document should be present. Just two simple checks for the example but think about 8 more checks before I have successfully processed my document. What would have your preference? for (Document document : List<Document> documents) { if (!fileIsPresent(document)) { doSomethingWithThisResult("File is not present"); continue; } if (!isSomethingInTheDocumentPresent(document)) { doSomethingWithThisResult("Something is not in the document"); continue; } doSomethingWithTheSucces(); } Or for (Document document : List<Document> documents) { try { fileIsPresent(document); isSomethingInTheDocumentPresent(document); doSomethingWithTheSucces(); } catch (ProcessingException e) { doSomethingWithTheExceptionalCase(e.getMessage()); } } public boolean fileIsPresent(Document document) throws ProcessingException { ... throw new ProcessingException("File is not present"); } public boolean isSomethingInTheDocumentPresent(Document document) throws ProcessingException { ... throw new ProcessingException("Something is not in the document"); } What is more readable. What is best? Is there even a better approach of doing this (maybe using a design pattern of some sort)? As far as readability goes my preference currently is the Exception variant... What is yours?

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  • setting default value of superglobal

    - by Prasoon Saurav
    I have been working on a Timesheet Management website. I have my home page as index.php //index.php <?php session_start(); if($_SESSION['logged']=='set') { $x=$_SESSION['username']; echo '<div align="right">'; echo 'Welcome ' .$x.'<br/>'; echo'<a href="logout.php" class="links">&nbsp;<b><u>Logout</u></b></a>' ; } else if($_SESSION['logged']='unset') { echo'<form id="searchform" method="post" action="processing.php"> <div> <div align="right"> Username&nbsp;<input type="text" name="username" id="s" size="15" value="" /> &nbsp;Password&nbsp;<input type="password" name="pass" id="s" size="15" value="" /> <input type="submit" name="submit" value="submit" /> </div> <br /> </div> </form> '; } ?> The problem I am facing is that during the first run of this script I get an error Notice: Undefined index: logged in C:\wamp\www\ps\index.php but after refreshing the page the error vanishes. How can I correct this problem? logged is a variable which helps determine whether the user is logged in or not. When the user is logged in $_SESSION['logged'] is set, otherwise unset. I want the default value of $_SESSION['logged'] to be unset prior to the execution of the script. How can I solve this problem?

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  • Why do case class companion objects extend FunctionN?

    - by retronym
    When you create a case class, the compiler creates a corresponding companion object with a few of the case class goodies: an apply factory method matching the primary constructor, equals, hashCode, and copy. Somewhat oddly, this generated object extends FunctionN. scala> case class A(a: Int) defined class A scala> A: (Int => A) res0: (Int) => A = <function1> This is only the case if: There is no manually defined companion object There is exactly one parameter list There are no type arguments The case class isn't abstract. Seems like this was added about two years ago. The latest incarnation is here. Does anyone use this, or know why it was added? It increases the size of the generated bytecode a little with static forwarder methods, and shows up in the #toString() method of the companion objects: scala> case class A() defined class A scala> A.toString res12: java.lang.String = <function0>

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  • Write Null/Nothing value with Databinding

    - by clawson
    I have extended a MaskedTextBox component to add some functionality. The text property of the extended MaskedTextBox is bound to a DateTime? property and the format of binding is set to a time format of "HH:mm:ss" (i.e. 24hr time). So that this masked text box will capture the display a time. The extra functionality I have added is to make the component readonly unless the component is double clicked or the enter button is pressed (the back color of the control helps to inform the users if the component is locked/readonly or not). When the enter button is pressed I also suspend the bindings so that bound data is updated the users input won't be lost. The information is then written back to the value and databindings resumed when the user presses the enter key again. This all works fine up to here, with values written and displayed as would be expected. However, I also want to write the null or nothing value to the DateTime? property if the user hasn't entered any text (or invalid text but let's just stick with no text) when enter key is pressed to submit the new value. Unlike with other valid entries in the MaskedTextBox, with no text entered when i execute: Me.DataBindings("Text").WriteValue() (when 'locking' the MaskedTextBox) it then branches to the bound properties Get method as I step into each line of code in the debugger (as opposed to the Set method with other valid entries) How can I write this null/nothing/"" value to the DateTime? property when no text "" is entered into the MaskedTextBox? Thanks for the help!

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  • Recycle Freed Objects

    - by uray
    suppose I need to allocate and delete object on heap frequently (of arbitrary size), is there any performance benefit if instead of deleting those objects, I will return it back to some "pool" to be reused later? would it give benefit by reduce heap allocation/deallocation?, or it will be slower compared to memory allocator performance, since the "pool" need to manage a dynamic collection of pointers. my use case: suppose I create a queue container based on linked list, and each node of that list are allocated on the heap, so every call to push() and pop() will allocate and deallocate that node: ` template <typename T> struct QueueNode { QueueNode<T>* next; T object; } template <typename T> class Queue { void push(T object) { QueueNode<T>* newNode = QueueNodePool<T>::get(); //get recycled node if(!newNode) { newNode = new QueueNode<T>(object); } // push newNode routine here.. } T pop() { //pop routine here... QueueNodePool<T>::store(unusedNode); //recycle node return unusedNode->object; } } `

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  • Overriding to_xml for collection of ActiveRecord objects

    - by Chirantan
    Okay, I know you can override the to_xml method for a single instance of ActiveRecord object and it works just fine for me. But how would I go about overriding the to_xml method for collection of objects? Suppose for Task model instance, I implemented to_xml which looks like this. def to_xml super(:methods => [:tag_list], :include => {:project => {:include => {:folder => {}}}, :folder => {}}) end Works just fine when a single task is to be serialized to xml. But when my code runs for collection of tasks, like in the following piece of code render :xml => @tasks.to_xml I get wrong number of arguments (1 for 0) /home/chirantan/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/array/conversions.rb:189:in `to_xml' /home/chirantan/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/array/conversions.rb:189:in `to_xml' /home/chirantan/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/array/conversions.rb:189:in `each' /home/chirantan/.gem/ruby/1.8/gems/activesupport-2.3.5/lib/active_support/core_ext/array/conversions.rb:189:in `to_xml' /var/lib/gems/1.8/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `call' /var/lib/gems/1.8/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `_nested_structures' /var/lib/gems/1.8/gems/builder-2.1.2/lib/builder/xmlbase.rb:58:in `method_missing' /var/lib/gems/1.8/gems/builder-2.1.2/lib/builder/xmlbase.rb:31:in `tag!' /~/blah/app/controllers/tasks_controller.rb:412:in `completed' How do I make this work?

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  • Delphi : Handling the fact that Strings are not Objects

    - by awmross
    I am trying to write a function that takes any TList and returns a String representation of all the elements of the TList. I tried a function like so function ListToString(list:TList<TObject>):String; This works fine, except you can't pass a TList to it. E2010 Incompatible types: 'TList<System.TObject>' and 'TList<System.string>' In Delphi, a String is not an Object. To solve this, I've written a second function: function StringListToString(list:TList<string>):String; Is this the only solution? Are there other ways to treat a String as more 'object-like'? In a similar vein, I also wanted to write an 'equals' function to compare two TLists. Again I run into the same problem function AreListsEqual(list1:TList<TObject>; list2:TList<TObject>):boolean; Is there any way to write this function (perhaps using generics?) so it can also handle a TList? Are there any other tricks or 'best practises' I should know about when trying to create code that handles both Strings and Objects? Or do I just create two versions of every function? Can generics help? I am from a Java background but now work in Delphi. It seems they are lately adding a lot of things to Delphi from the Java world (or perhaps the C# world, which copied them from Java). Like adding equals() and hashcode() to TObject, and creating a generic Collections framework etc. I'm wondering if these additions are very practical if you can't use Strings with them.

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  • Inereritance of clousure objects and overriding of methods

    - by bobikk
    I need to extend a class, which is encapsulated in a closure. This base class is following: var PageController = (function(){ // private static variable var _current_view; return function(request, new_view) { ... // priveleged public function, which has access to the _current_view this.execute = function() { alert("PageController::execute"); } } })();` Inheritance is realised using the following function: function extend(subClass, superClass){ var F = function(){ }; F.prototype = superClass.prototype; subClass.prototype = new F(); subClass.prototype.constructor = subClass; subClass.superclass = superClass.prototype; StartController.cache = ''; if (superClass.prototype.constructor == Object.prototype.constructor) { superClass.prototype.constructor = superClass; } } I subclass the PageController: var StartController = function(request){ // calling the constructor of the super class StartController.superclass.constructor.call(this, request, 'start-view'); } // extending the objects extend(StartController, PageController); // overriding the PageController::execute StartController.prototype.execute = function() { alert('StartController::execute'); } Inheritance is working. I can call every PageController's method from StartController's instance. However, method overriding doesn't work: var startCont = new StartController(); startCont.execute(); alerts "PageController::execute". How should I override this method?

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  • jquery - problem with executing annimation of two separate objects, one after another

    - by MoreThanChaos
    Hello I have problem to put together animations of two separate objects to second one start when first one ends. I tried to use callback but it seems that i make some syntax misteakes which crash jQuery or cause some unexpected behaviour. It seems that i'm stuck so I'd like to ask You for best way to put these animations together to act the way I want. in mouseenter 1st .pp grows, 2nd .tt fade in in mouseleave 1st .tt fade out, 2nd .pp shrink It's alsp relevant that animations doesn't pile up, i mean here animation called by one event doesnt wait until other animation in progress will end. In generall exactly what is below but yo be animated one after another, not simultanously. $('.pp').bind({ mouseenter: function() { $(this).animate({ width: $(this).children(".tt").outerWidth(), height: $(this).children(".tt").outerHeight() },{duration:1000,queue:false} ); $(this).children(".tt").animate({ opacity: 1.0 }, {duration:1000,queue:false}); }, mouseleave: function() { $(this).children(".tt").animate({ opacity: 0 }, {duration:1000,queue:false}); $(this).animate({ width: 17, height: 17 }, {duration:1000,queue:false}); } });

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  • iphone NSMutableArray loses objects at end of method

    - by Brodie4598
    Hello - in my app, an NSMutableArray is populated with an object in viewDidLoad (eventually there will be many objects but I'm just doing one til I get it working right). I also start a timer that starts a method that needs to access the NSMutableArray every few seconds. The NSMutableArray works fine in viewDidLoad, but as soon as that method is finished, it loses the object. myApp.h @interface MyApp : UIViewController { NSMutableArray *myMutableArray; NSTimer *timer; } @property (nonatomic, retain) NSMutableArray *myMutableArray; @property (nonatomic, retain) NSTimer *timer; @end myApp.m #import "MyApp.h" @implementation MyApp @synthesize myMutableArray; - (void) viewDidLoad { cycleTimer = [NSTimer scheduledTimerWithTimeInterval:4.0 target:self selector:@selector(newCycle) userInfo: nil repeats:YES]; MyObject *myCustomUIViewObject = [[MyObject alloc]init]; [myMutableArray addObject:myCustomUIViewObject]; [myCustomUIViewObject release]; NSLog(@"%i",[myMutableArray count]); /////outputs "1" } -(void) newCycle { NSLog(@"%i",[myMutableArray count]); /////outputs "0" ?? why is this?? }

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  • How to add objects to NSArray from a different class with ARC

    - by Space Dust
    I needed to convert my code to ARC. I have an NSArray that I use to draw a path. I fill the objects of NSArray values from a different class. Problem is after converting to ARC, NSArray returns always null I can not see what I am doing wrong. bug.h @interface Ladybug : CCSprite <CCTargetedTouchDelegate>{ CCArray *linePathPosition; } @property (nonatomic, strong) CCArray *linePathPosition; @end bug.m @synthesize linePathPosition; -(id) init { if( (self=[super init] )) { self.linePathPosition = [[CCArray alloc] init]; } return self; } -(void) updatePosition:(CGPoint) position { [self.linePathPosition addObject:[NSValue valueWithCGPoint:position]]; NSLog(@"line path %@",linePathPosition); } -(void) breakMoveLadyBug { [self.linePathPosition removeAllObjects]; } In main .m - (void)ccTouchMoved:(UITouch *)touch withEvent:(UIEvent *)event { Ladybug *ladybug1 = (Ladybug *)[self getChildByTag:99]; CCMotionStreak* streak = (CCMotionStreak *)[self getChildByTag:999]; CGPoint touchLocation = [touch locationInView: [touch view]]; CGPoint curPosition = [[CCDirector sharedDirector] convertToGL:touchLocation]; if (ladybug1.isSelected) { streak.position = curPosition; [ladybug1 updatePosition:curPosition]; NSLog(@"Cur position %@",NSStringFromCGPoint(curPosition)); if (!ladybug1.isMoving) { [ladybug1 startMoveLadyBug]; } } } Log: Cur position {331, 110} line path (null) What am I doing wrong? What is the proper way to define and init NSArray with ARC?

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  • How to get an enum value from an assembly using late binding in C#

    - by tetranz
    Hello I have a C# 3.0 WinForms application which is occasionally required to control Excel with automation. This is working nicely with normal early binding but I've had some problems when people don't have Excel installed but still want to use my app except for the Excel part. Late binding seems to be a solution to this. Late binding is rather tedious in C# 3 but I'm not doing anything particularly difficult. I'm following http://support.microsoft.com/kb/302902 as a starter and it's working out well. My question is how can I use an enum by name? e.g, how can I use reflection to get the value of Microsoft.Office.Interop.Excel.XlFileFormat.xlTextWindows so that I can use it an InvokeMethod call? I know the easiest way is probably to create my own local enum with the same "magic" integer value but it would be nicer to be able to access it by name. The docs often don't list the value so to get it I probably need to have a little early bound test app that can tell me the value. Thanks

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  • How to set an empty value using XPath?

    - by Ricardo
    Using this xml example: <templateitem itemid="5"> <templateitemdata>%ARN%</templateitemdata> </templateitem> <templateitem itemid="6"> <templateitemdata></templateitemdata> </templateitem> I am using XPath to get and set Node values. The code I am using to get the nodes is: private static Node ***getNode***(Document doc, String XPathQuery) throws XPathExpressionException { XPath xpath = XPathFactory.newInstance().newXPath(); XPathExpression expr = xpath.compile(XPathQuery); Object result = expr.evaluate(doc, XPathConstants.NODESET); NodeList nodes = (NodeList) result; if(nodes != null && nodes.getLength() >0) return nodes.item(0); throw new XPathExpressionException("No node list found for " + XPathQuery); } To get %ARN% value: "//templateitem[@itemid=5]/templateitemdata/text()" and with the getNode method I can get the node, and then call the getNodeValue(). Besides getting that value, I would like to set templateitemdata value for the "templateitem[@itemid=6]" since its empty. But the code I use can't get the node since its empty. The result is null. Do you know a way get the node so I can set the value?

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  • Remove duplicate records/objects uniquely identified by multiple attributes

    - by keruilin
    I have a model called HeroStatus with the following attributes: id user_id recordable_type hero_type (can be NULL!) recordable_id created_at There are over 100 hero_statuses, and a user can have many hero_statuses, but can't have the same hero_status more than once. A user's hero_status is uniquely identified by the combination of recordable_type + hero_type + recordable_id. What I'm trying to say essentially is that there can't be a duplicate hero_status for a specific user. Unfortunately, I didn't have a validation in place to assure this, so I got some duplicate hero_statuses for users after I made some code changes. For example: user_id = 18 recordable_type = 'Evil' hero_type = 'Halitosis' recordable_id = 1 created_at = '2010-05-03 18:30:30' user_id = 18 recordable_type = 'Evil' hero_type = 'Halitosis' recordable_id = 1 created_at = '2009-03-03 15:30:00' user_id = 18 recordable_type = 'Good' hero_type = 'Hugs' recordable_id = 1 created_at = '2009-02-03 12:30:00' user_id = 18 recordable_type = 'Good' hero_type = NULL recordable_id = 2 created_at = '2009-012-03 08:30:00' (Last two are not a dups obviously. First two are.) So what I want to do is get rid of the duplicate hero_status. Which one? The one with the most-recent date. I have three questions: How do I remove the duplicates using a SQL-only approach? How do I remove the duplicates using a pure Ruby solution? Something similar to this: http://stackoverflow.com/questions/2790004/removing-duplicate-objects. How do I put a validation in place to prevent duplicate entries in the future?

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  • how to read in a list of custom configuration objects

    - by Johnny
    hi, I want to implement Craig Andera's custom XML configuration handler in a slightly different scenario. What I want to be able to do is to read in a list of arbitrary length of custom objects defined as: public class TextFileInfo { public string Name { get; set; } public string TextFilePath { get; set; } public string XmlFilePath { get; set; } } I managed to replicate Craig's solution for one custom object but what if I want several? Craig's deserialization code is: public class XmlSerializerSectionHandler : IConfigurationSectionHandler { public object Create(object parent, object configContext, XmlNode section) { XPathNavigator nav = section.CreateNavigator(); string typename = (string)nav.Evaluate("string(@type)"); Type t = Type.GetType(typename); XmlSerializer ser = new XmlSerializer(t); return ser.Deserialize(new XmlNodeReader(section)); } } I think I could do this if I could get Type t = Type.GetType("System.Collections.Generic.List<TextFileInfo>") to work but it throws Could not load type 'System.Collections.Generic.List<Test1.TextFileInfo>' from assembly 'Test1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.

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  • Hibernate: Querying objects by attributes of inherited classes

    - by MichaelD
    Hi all, I ran into a problem with Hibernate concerning queries on classes which use inheritance. Basically I've the following class hierarchy: @Entity @Table( name = "recording" ) class Recording { ClassA attributeSet; ... } @Entity @Inheritance( strategy = InheritanceType.JOINED ) @Table( name = "classA" ) public class ClassA { String Id; ... } @Entity @Table( name = "ClassB1" ) @PrimaryKeyJoinColumn( name = "Id" ) public class ClassB1 extends ClassA { private Double P1300; private Double P2000; } @Entity @Table( name = "ClassB2" ) @PrimaryKeyJoinColumn( name = "Id" ) public class ClassB2 extends ClassA { private Double P1300; private Double P3000; } The hierarchy is already given like this and I cannot change it easily. As you can see ClassB1 and ClassB2 inherit from ClassA. Both classes contain a set of attributes which sometimes even have the same names (but I can't move them to ClassA since there are possible more sub-classes which do not use them). The Recording class references one instance of one of this classes. Now my question: What I want to do is selecting all Recording objects in my database which refer to an instance of either ClassB1 or ClassB2 with e.g. the field P1300 == 15.5 (so this could be ClassB1 or ClassB2 instances since the P1300 attribute is declared in both classes). What I tried is something like this: Criteria criteria = session.createCriteria(Recording.class); criteria.add( Restrictions.eq( "attributeSet.P1300", new Double(15.5) ) ); criteria.list(); But since P1300 is not an attribute of ClassA hibernate throws an exception telling me: could not resolve property: P1300 of: ClassA How can I tell hibernate that it should search in all subclasses to find the attribute I want to filter? Thanks MichaelD

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  • MySQL default value based on view

    - by Jake
    Basically I have a bunch of views based on a simple discriminator column (eg. CREATE VIEW tablename AS SELECT * FROM tablename WHERE discrcolumn = "discriminator value"). Upon inserting a new row into this view, it should insert "discriminator value" into discrcolumn. I tried this, but apparently MySQL doesn't figure this out itself, as it throws an error "Field of view viewname underlying table does not have a default value". The discriminator column is set to NOT NULL of course. How do I mend this? Perhaps a pre-insert trigger? UPDATE: Triggers won't work on views, see below comment. Would it work to create a trigger on the table which uses a variable, and set that variable at establishing the connection? For each connection the value of that variable would be the same, but it could differ from other connections. EDIT: This appears to work... Setup: CREATE TRIGGER insert_[tablename] BEFORE INSERT ON [tablename] FOR EACH ROW SET NEW.[discrcolumn] = @variable Runtime: SET @variable = [descrvalue]; INSERT INTO [viewname] ([columnlist]) VALUES ([values]);

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