Search Results

Search found 5648 results on 226 pages for 'collection'.

Page 52/226 | < Previous Page | 48 49 50 51 52 53 54 55 56 57 58 59  | Next Page >

  • Thread Safety of C# List<T> for readers

    - by ILIA BROUDNO
    I am planning to create the list once in a static constructor and then have multiple instances of that class read it (and enumerate through it) concurrently without doing any locking. In this article http://msdn.microsoft.com/en-us/library/6sh2ey19.aspx MS describes the issue of thread safety as follows: Public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe. A List can support multiple readers concurrently, as long as the collection is not modified. Enumerating through a collection is intrinsically not a thread-safe procedure. In the rare case where an enumeration contends with one or more write accesses, the only way to ensure thread safety is to lock the collection during the entire enumeration. To allow the collection to be accessed by multiple threads for reading and writing, you must implement your own synchronization. The "Enumerating through a collection is intrinsically not a thread-safe procedure." Statement is what worries me. Does this mean that it is thread safe for readers only scenario, but as long as you do not use enumeration? Or is it safe for my scenario?

    Read the article

  • what is wrong with this insert method in asp.net mvc?

    - by Pandiya Chendur
    My controller calls a repository class method on insert, [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create([Bind(Exclude = "Id")]FormCollection collection) { try { MaterialsObj materialsObj = new MaterialsObj(); materialsObj.Mat_Name = collection["Mat_Name"]; materialsObj.Mes_Id = Convert.ToInt64(collection["MeasurementType"]); materialsObj.Mes_Name = collection["Mat_Type"]; materialsObj.CreatedDate = System.DateTime.Now; materialsObj.CreatedBy = Convert.ToInt64(1); materialsObj.IsDeleted = Convert.ToInt64(1); consRepository.createMaterials(materialsObj); return RedirectToAction("Index"); } catch { return View(); } } and my repository class has this, public MaterialsObj createMaterials(MaterialsObj materialsObj) { db.Materials.InsertOnSubmit(materialsObj); return materialsObj; } But when i compile this i get The best overloaded method match for 'System.Data.Linq.Table<CrMVC.Models.Material>.InsertOnSubmit(CrMVC.Models.Material)' has some invalid arguments... cannot convert from 'CrMVC.BusinessObjects.MaterialsObj' to 'CrMVC.Models.Material'.. am i missing something?

    Read the article

  • How to detect if a LINQ enumeration is materialized?

    - by Peter Lillevold
    Is there some way of detecting whether an enumerable built using LINQ (to Objects in this case) have been materialized or not? Other than trying to inspect the type of the underlying collection? Specifically, since enumerable.ToArray() will build a new array even if the underlying collection already is an array I'm looking for a way of avoiding ToArray() being called twice on the same collection.

    Read the article

  • How to add a SaveOrUpdateCopy event listener in NHibernate

    - by skrishna
    How can I add a event listener for SaveOrUpdateCopy in NHibernate ? I see that the ListenerType enumeration does not have a 'SaveOrUpdateCopy' type. I tried using the 'Merge' type, but that adds it to the MergeEventListeners collection. The SaveOrUpdateCopy invokes the events from the SaveOrUpdateCopyEventListeners collection. How can I add my event class to the SaveOrUpdateCopyEventListeners collection in NHibernate? Any help is appreciated.

    Read the article

  • What is the difference between the add and offer methods in a queue?

    - by Finbarr
    Take the PriorityQueue for example http://java.sun.com/j2se/1.5.0/docs/api/java/util/PriorityQueue.html#offer(E) According to the Collection API entry http://java.sun.com/j2se/1.5.0/docs/api/java/util/Collection.html the add method will often seek to ensure that an element exists within the Collection rather than adding duplicates. So my question is, what is the difference between the add and offer methods? Is it that the Offer method will add duplicates regardless? (I doubt that it is because if a Collection should only have distinct elements this would circumvent that).

    Read the article

  • Hibernate: update on parent-child relationship causes duplicate children

    - by TimmyJ
    I have a parent child relationship in which the parent has a collection of children (a set to be specific). The child collection is setup with cascade="all-delete-orphan". When I initially save the parent element everything works as expected. However, when I update the parent and save again, all the children are re-saved. This behavior leads me to believe that the parent is losing its reference to the collection of children, and therefore when persisting all the children are re-saved. It seems the only way to fix this is to not use the setter method of this child collection, but unfortunately this setter is called implicitly in my application (Spring MVC is used to bind a multi-select form element to this collection, and the setter is called by spring on the form submission). Overwriting this setter to not lose the reference (ie, do a colleciton.clear() and collection.addAll(newCollection) rather than collection = newCollection) is apparently a hibernate no-no, as is pointed out here: https://forum.hibernate.org/viewtopic.php?t=956859 Does anyone know how to circumvent this problem? I've posted some of my code below. The parent hibernate configuration: <hibernate-mapping package="org.fstrf.masterpk.domain"> <class name="ReportCriteriaBean" table="masterPkReportCriteria"> <id name="id" column="id"> <generator class="org.hibernate.id.IncrementGenerator" /> </id> <set name="treatmentArms" table="masterPkTreatmentArms" sort="org.fstrf.masterpk.domain.RxCodeComparator" lazy="false" cascade="all-delete-orphan" inverse="true"> <key column="runid"/> <one-to-many class="TreatmentArm"/> </set> </class> </hibernate-mapping> The parent object: public class ReportCriteriaBean{ private Integer id; private Set<TreatmentArm> treatmentArms; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public Set<TreatmentArm> getTreatmentArms() { return treatmentArms; } public void setTreatmentArms(Set<TreatmentArm> treatmentArms) { this.treatmentArms = treatmentArms; if(this.treatmentArms != null){ for(TreatmentArm treatmentArm : this.treatmentArms){ treatmentArm.setReportCriteriaBean(this); } } } The child hibernate configuration: <hibernate-mapping package="org.fstrf.masterpk.domain"> <class name="TreatmentArm" table="masterPkTreatmentArms"> <id name="id" column="id"> <generator class="org.hibernate.id.IncrementGenerator" /> </id> <many-to-one name="reportCriteriaBean" class="ReportCriteriaBean" column="runId" not-null="true" /> <property name="rxCode" column="rxCode" not-null="true"/> </class> </hibernate-mapping> The child object: public class TreatmentArm { private Integer id; private ReportCriteriaBean reportCriteriaBean; private String rxCode; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public ReportCriteriaBean getReportCriteriaBean() { return reportCriteriaBean; } public void setReportCriteriaBean(ReportCriteriaBean reportCriteriaBean) { this.reportCriteriaBean = reportCriteriaBean; } public String getRxCode() { return rxCode; } public void setRxCode(String rxCode) { this.rxCode = rxCode; } }

    Read the article

  • LINQ problem on remote machine

    - by HaMMeR
    I am using LINQ expressions in my code like this var obj = Collection.Single(collection = (collection.ShortName.Equals("AAA"))); The problem is that this line works fine for me, no problems. But when I upload the same executable to some remote machine with same 32 bit Windows XP. The code execution is just stopping at this line of source. Can anyone help me.

    Read the article

  • EntityManager does not update on flush()

    - by Sara
    Java EJB's EntityManager does not update data from a Consumer. A Consumer logs into a shop, buys some stuff and wants to look at his shopping-history. Everything is displayed but his last purchase. If he logs out and in, it shows. I have used JPA to persist buys/purchases (that are mapped to the Consumer)to DB. It seems like purchases from this session can't be detected. Code: public Buys buyItem(Consumer c, int amount) { Buys b = new Buys(); b.setConsumerId(c); b.setContent("DVD"); b.setPrice(amount); em.persist(b); em.flush(); return b; } public Collection getAllBuysFromUser(Consumer consumer) { Collection collection = consumer.getBuysCollection(); return collection; } Help!? Flush does not do the trick...

    Read the article

  • How does Backbone.js connect View to Model

    - by William Sham
    I am trying to learn backbone.js through the following example. Then I got stuck at the point ItemView = Backbone.View.extend why you can use this.model.get? I thought this is referring to the instance of ItemView that would be created. Then why would ItemView has a model property at all?!! (function($){ var Item = Backbone.Model.extend({ defaults: { part1: 'hello', part2: 'world' } }); var List = Backbone.Collection.extend({ model: Item }); var ItemView = Backbone.View.extend({ tagName: 'li', initialize: function(){ _.bindAll(this, 'render'); }, render: function(){ $(this.el).html('<span>'+this.model.get('part1')+' '+this.model.get('part2')+'</span>'); return this; } }); var ListView = Backbone.View.extend({ el: $('body'), events: { 'click button#add': 'addItem' }, initialize: function(){ _.bindAll(this, 'render', 'addItem', 'appendItem'); this.collection = new List(); this.collection.bind('add', this.appendItem); this.counter = 0; this.render(); }, render: function(){ $(this.el).append("<button id='add'>Add list item</button>"); $(this.el).append("<ul></ul>"); _(this.collection.models).each(function(item){ appendItem(item); }, this); }, addItem: function(){ this.counter++; var item = new Item(); item.set({ part2: item.get('part2') + this.counter }); this.collection.add(item); }, appendItem: function(item){ var itemView = new ItemView({ model: item }); $('ul', this.el).append(itemView.render().el); } }); var listView = new ListView(); })(jQuery);

    Read the article

  • Magento 1.4 Load By Category Not Working

    - by LinuxGnut
    Hi folks. I have a Magento helper class I wrote that works wonderfully in 1.3. However, we're working on a new install of 1.4 and filtering by category won't work for some reason. function __construct() { Mage::app(); $this-model = Mage::getModel('catalog/product'); $this-collection = $this-model-getCollection(); $this-collection-addAttributeToFilter('status', 1);//enabled $this-collection-addAttributeToSelect('*'); } function filterByCategoryID($catID) { $this-collection-addCategoryFilter(Mage::getModel('catalog/category')-load($catID)); } I can't figure out why this isn't working in 1.4. Has anyone else come into this issue?

    Read the article

  • Java - Thread safety of ArrayList constructors

    - by andy boot
    I am looking at this piece of code. This constructor delegates to the native method "System.arraycopy" Is it Thread safe? And by that I mean can it ever throw a ConcurrentModificationException? public Collection<Object> getConnections(Collection<Object> someCollection) { return new ArrayList<Object>(someCollection); } Does it make any difference if the collection being copied is ThreadSafe eg a CopyOnWriteArrayList? public Collection<Object> getConnections(CopyOnWriteArrayList<Object> someCollection) { return new ArrayList<Object>(someCollection); }

    Read the article

  • Inheritance of TCollectionItem

    - by JamesB
    I'm planning to have collection of items stored in a TCollection. Each item will derive from TBaseItem which in turn derives from TCollectionItem, With this in mind the Collection will return TBaseItem when an item is requested. Now each TBaseItem will have a Calculate function, in the the TBaseItem this will just return an internal variable, but in each of the derivations of TBaseItem the Calculate function requires a different set of parameters. The Collection will have a Calculate All function which iterates through the collection items and calls each Calculate function, obviously it would need to pass the correct parameters to each function I can think of three ways of doing this: Create a virtual/abstract method for each calculate function in the base class and override it in the derrived class, This would mean no type casting was required when using the object but it would also mean I have to create lots of virtual methods and have a large if...else statement detecting the type and calling the correct "calculate" method, it also means that calling the calculate method is prone to error as you would have to know when writing the code which one to call for which type with the correct parameters to avoid an Error/EAbstractError. Create a record structure with all the possible parameters in and use this as the parameter for the "calculate" function. This has the added benefit of passing this to the "calculate all" function as it can contain all the parameters required and avoid a potentially very long parameter list. Just type casting the TBaseItem to access the correct calculate method. This would tidy up the TBaseItem quite alot compared to the first method. What would be the best way to handle this collection?

    Read the article

  • Get category count for a category where only the child categories have products

    - by Matthew
    I'm having problems getting a count for a category collection that will include products in any of that categories children. However I don't want just a full count I want to filter that count by a product collection (so only include products in the count that appear in the product collection)... Any suggestions? Code to get a filtered product collection (filtered by a multiselect attribute) /** @var $attribute Mage_Eav_Model_Entity_Attribute */ $valuesCollection = Mage::getResourceModel('eav/entity_attribute_option_collection') ->setAttributeFilter($attribute->getId()) ->addFieldToFilter('value', array ('like' => $make)) ->addFieldToSelect('option_id') ->setStoreFilter(0, false); $set = array(); foreach($valuesCollection as $option){ $set[] = $option->getData('option_id'); } $_productCollection = Mage::getResourceModel('catalog/product_collection') ->addAttributeToFilter('sparex_makemodel', array('in' => $set ) ) ->addAttributeToSelect('*'); I'm getting the child categories for a given category like thus.. $childCats = Mage::getModel('catalog/category')->load(2)->getChildrenCategories(); Now none of these categories have products assigned to them, however their children (or children of children) do. I want to produce a count for these categories that includes the child categories but only where the products are in my filtered collection.

    Read the article

  • WPF: Bind DataGrid to List<String>

    - by Sam
    Funny, how sometimes the simple things bite me in the behind. I can bind a DataGrid nicely to a Collection of some arbitrary class, using a DataGridTextColumn like this: <DataGridTextColumn Header="Name" Binding="{Binding Name}"/> Now I want to bind a DataGrid to a simple Collection. So since there is no property "Name" or something like that to bind to, how do I write the binding: <DataGridTextColumn Header="Name" Binding="{Binding ???}"/> String has no Property "Value" or something like that. And if I just write {Binding } I'll end up with a one-way-binding, unable to write changes back to the Collection. Thinking about it, I think it is not possible to bind to a collection, so I do need to wrap my string into a class? Or is there a way?

    Read the article

  • Can you use MongoDB map/reduce to migrate data?

    - by Brian Armstrong
    I have a large collection where I want to modify all the documents by populating a field. A simple example might be caching the comment count on each post: class Post field :comment_count, type: Integer has_many :comments end class Comment belongs_to :post end I can run it in serial with something like: Post.all.each do |p| p.udpate_attribute :comment_count, p.comments.count end But it's taking 24 hours to run (large collection). I was wondering if mongo's map/reduce could be used for this? But I haven't seen a great example yet. I imagine you would map off the comments collection and then store the reduced results in the posts collection. Am I on the right track?

    Read the article

  • Best way to bind directly to objects returned from a web service

    - by zachary
    In silverlight 3 I had an object that had a property that was an observable collection. I returned this via a web service then databinded to it. Upgrade to silveright 4..... Now my program crashes because the Observable Collection is converted to an array. What is the best way to do this? Observable collection is not even an option any longer.

    Read the article

  • Select n+1 problem

    - by Arnis L.
    Foo has Title. Bar references Foo. I have a collection with Bars. I need a collection with Foo.Title. If i have 10 bars in collection, i'll call db 10 times. bars.Select(x=x.Foo.Title) At the moment this (using NHibernate Linq and i don't want to drop it) retrieves Bar collection. var q = from b in Session.Linq<Bar>() where ... select b; I read what Ayende says about this. Another related question. A bit of documentation. And another related blog post. Maybe this can help? What about this? Maybe MultiQuery is what i need? :/ But i still can't 'compile' this in proper solution. How to avoid select n+1?

    Read the article

  • Getting differences between collections in LINQ

    - by dotnetdev
    Hi, I have a collection of image paths, and a larger collection of Image objects (Which contain a path property). I have the code to check for any matching images, but if there are supposed to be four matching image paths (as that is how many are in the first collection), and there is less than this, how can I get the missing one without writing loops? List<string> ImagesToCheck = new List<string>() { "", "s", "ssdd" }; IEnumerable<HtmlImage> Images = manager.ActiveBrowser.Find.AllControls<HtmlImage>(); var v = from i in Images where ImagesToCheck.Any(x => x == i.Src) select i; if (v.Count() < 3) { } So I need to get the items which are not in the collection titled v, but are in ImagesToCheck. How could I do this with LINQ? Thanks

    Read the article

  • Distinct by property of class by linq

    - by phenevo
    I have a collection: List<Car> cars=new List<Car> Cars are uniquely identified by CarCode. I have three cars in the collection, and two with identical CarCodes. How can I use LINQ to convert this collection to Cars with unique CarCodes?

    Read the article

  • Magento - How to select mysql rows by max value?

    - by Damodar Bashyal
    mysql> SELECT * FROM `log_customer` WHERE `customer_id` = 224 LIMIT 0, 30; +--------+------------+-------------+---------------------+-----------+----------+ | log_id | visitor_id | customer_id | login_at | logout_at | store_id | +--------+------------+-------------+---------------------+-----------+----------+ | 817 | 50139 | 224 | 2011-03-21 23:56:56 | NULL | 1 | | 830 | 52317 | 224 | 2011-03-27 23:43:54 | NULL | 1 | | 1371 | 136549 | 224 | 2011-11-16 04:33:51 | NULL | 1 | | 1495 | 164024 | 224 | 2012-02-08 01:05:48 | NULL | 1 | | 2130 | 281854 | 224 | 2012-11-13 23:44:13 | NULL | 1 | +--------+------------+-------------+---------------------+-----------+----------+ 5 rows in set (0.00 sec) mysql> SELECT * FROM `customer_entity` WHERE `entity_id` = 224; +-----------+----------------+---------------------------+----------+---------------------+---------------------+ | entity_id | entity_type_id | email | group_id | created_at | updated_at | +-----------+----------------+---------------------------+----------+---------------------+---------------------+ | 224 | 1 | [email protected] | 3 | 2011-03-21 04:59:17 | 2012-11-13 23:46:23 | +-----------+----------------+---------------------------+----------+--------------+----------+-----------------+ 1 row in set (0.00 sec) How can i search for customers who hasn't logged in for last 10 months and their account has not been updated for last 10 months. I tried below but failed. $collection = Mage::getModel('customer/customer')->getCollection(); $collection->getSelect()->joinRight(array('l'=>'log_customer'), "customer_id=entity_id AND MAX(l.login_at) <= '" . date('Y-m-d H:i:s', strtotime('10 months ago')) . "'")->group('e.entity_id'); $collection->addAttributeToSelect('*'); $collection->addFieldToFilter('updated_at', array( 'lt' => date('Y-m-d H:i:s', strtotime('10 months ago')), 'datetime'=>true, )); $collection->addAttributeToFilter('group_id', array( 'neq' => 5, )); Above tables have one customer for reference. I have no idea how to use MAX() on joins. Thanks UPDATE: This seems returning correct data, but I would like to do magento way using resource collection, so i don't need to do load customer again on for loop. $read = Mage::getSingleton('core/resource')->getConnection('core_read'); $sql = "select * from ( select e.*,l.login_at from customer_entity as e left join log_customer as l on l.customer_id=e.entity_id group by e.entity_id order by l.login_at desc ) as l where ( l.login_at <= '".date('Y-m-d H:i:s', strtotime('10 months ago'))."' or ( l.created_at <= '".date('Y-m-d H:i:s', strtotime('10 months ago'))."' and l.login_at is NULL ) ) and group_id != 5"; $result = $read->fetchAll($sql); I have loaded full shell script to github https://github.com/dbashyal/Magento-ecommerce-Shell-Scripts/blob/master/shell/suspendCustomers.php

    Read the article

  • LinQ optimization

    - by Budda
    Here is a peace of code: void MyFunc(List<MyObj> objects) { MyFunc1(objects); foreach( MyObj obj in objects.Where(obj1=>obj1.Good)) { // Do Action With Good Object } } void MyFunc1(List<MyObj> objects) { int iGoodCount = objects.Where(obj1=>obj1.Good).Count(); BeHappy(iGoodCount); // do other stuff with 'objects' collection } Here we see that collection is analyzed twice and each time the value of 'Good' property is checked for each member: 1st time when calculating count of good objects, 2nd - when iterating through all good objects. It is desirable to have that optimized, and here is a straightforward solution: before call to MyFunc1 makecreate an additional temporary collection of good objects only (goodObjects, it can be IEnumerable); get count of these objects and pass it as an additional parameter to MyFunc1; in the 'MyFunc' method iterate not through 'objects.Where(...)' but through the 'goodObjects' collection. Not too bad approach (as far as I see), but additional parameter is required to be passed. Question: is there any LinQ out-of-the-box functionality that allows any caching during 1st Where().Count(), remembering a processed collection and use it in the next iteration? Any thoughts are welcome. Thanks.

    Read the article

  • How can I have a Foo* iterator to a vector of Foo?

    - by mghie
    If I have a class that contains a std::list<Foo>, how can I implement iterators to a Foo* collection, preferably without using boost? I'd rather not maintain a parallel collection of pointers. For now I have std::list<Foo>, mostly so that removing or inserting an element does not invalidate all other iterators, but would it be possible to implement other iterators too, so that the collection type used in the implementation is opaque to the user of the class?

    Read the article

  • Best Java thread-safe locking mechanism for collections?

    - by Simon
    What would be the least-slow thread-safe mechanism for controlling multiple accesses to a collection in Java? I am adding objects to the top of a collection and i am very unsure what would be the best performing collection. Would it be a vector or a queue? I originally thought an ArrayList would be fast but i ran some experiments and it was very slow. EDIT: In my insertion testing a Vector delared using volatile seems to be the fastest?

    Read the article

< Previous Page | 48 49 50 51 52 53 54 55 56 57 58 59  | Next Page >