Search Results

Search found 40226 results on 1610 pages for 'object relational model'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 472/1610 | < Previous Page | 468 469 470 471 472 473 474 475 476 477 478 479  | Next Page >

  • Storing large numbers of varying size objects on disk

    - by Foredecker
    I need to develop a system for storing large numbers (10's to 100's of thousands) of objects. Each object is email-like - there is a main text body, and several ancillary text fields of limited size. A body will be from a few bytes, to several KB in size. Each item will have a single unique ID (probably a GUID) that identifies it. The store will only be written to when an object is added to it. It will be read often. Deletions will be rare. The data is almost all human readable text so it will be readily compressible. A system that lets me issue the I/Os and mange the memory and caching would be ideal. I'm going to keep the indexes in memory, using it to map indexes to the single (and primary) key for the objects. Once I have the key, then I'll load it from disk, or the cache. The data management system needs to be part of my application - I do not want to depend on OS services. Or separately installed packages. Native (C++) would be best, but a manged (C#) thing would be ok. I believe that a database is an obvious choice, but this needs to be super-fast for look up and loading into memory of an object. I am not experienced with data base tech and I'm concerned that general relational systems will not handle all this variable sized data efficiently. (Note, this has nothing to do with my job - its a personal project.) In your experience, what are the viable alternatives to a traditional relational DB? Or would a DB work well for this?

    Read the article

  • How solve consumer/producer task using semaphores

    - by user1074896
    I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

    Read the article

  • Windows App. Thread Aborting Issue

    - by Patrick
    I'm working on an application that has to make specific decisions based on files that are placed into a folder being watched by a file watcher. Part of this decision making process involves renaming files before moving them off to another folder to be processed. Since I'm working with files of all different sizes I created an object that checks the file in a seperate thread to verify that it is "available" and when it is it fires an event. When I run the rename code from inside this available event it works. public void RenameFile_Test() { string psFilePath = @"C:\File1.xlsx"; tgt_File target = new FileObject(psFilePath); target.FileAvailable += new FileEventHandler(OnFileAvailable); target.FileUnAvailable += new FileEventHandler(OnFileUnavailable); } private void OnFileAvailable(object source, FileEventArgs e) { ((FileObject)source).RenameFile(@"C:\File2.xlsx"); } The problem I'm running into is that when the extensions are different from the source file and the rename to file I am making a call to a conversion factory that returns a factory object based on the type of conversion and then converts the file accordingly before doing the rename. When I run that particular piece of code in unit test it works, the factory object is returned, and the conversion happens correctly. But when I run it within the process I get up to the... moExcelApp = new Application(); part of converting an .xls or .xlsx to a .csv and i get a "Thread was being Aborted" error. Any thoughts? Update: There is a bit more information and a bit of map of how the application works currently. Client Application running FSW On File Created event Creates a FileObject passing in the path of the file. On construction the file is validated: if file exists is true then, Thread toAvailableCheck = new Thread(new ThreadStart(AvailableCheck)); toAvailableCheck.Start(); The AvailableCheck Method repeatedly tries to open a streamreader to the file until the reader is either created or the number of attempts times out. If the reader is opened, it fires the FileAvailable event, if not it fires the FileUnAvailable event, passing back itself in the event. The client application is wired to catch those events from inside the Oncreated event of the FSW. the OnFileAvailable method then calls the rename functionality which contains the excel interop call. If the file is being renamed (not converted, extensions stay the same) it does a move to change the name from the old file name to the new, and if its a conversion it runs a conversion factory object which returns the correct type of conversion based on the extensions of the source file and the destination file name. If it is a simple rename it works w/o a problem. If its a conversion (which is the XLS to CSV object that is returned as a part of the factory) the very first thing it does is create a new application object. That is where the application bombs. When i test the factory and conversion/rename process outside of the thread and in its own unit test the process works w/o a problem. Update: I tested the Excel Interop inside a thread by doing this: [TestMethod()] public void ExcelInteropTest() { Thread toExcelInteropThreadTest = new Thread(new ThreadStart(Instantiate_App)); toExcelInteropThreadTest.Start(); } private void Instantiate_App() { Application moExcelApp = new Application(); moExcelApp.Quit(); } And on the line where the application is instatntiated I got the 'A first chance exception of type 'System.Threading.ThreadAbortException' error. So I added; toExcelInteropThreadTest.SetApartmentState(ApartmentState.MTA); after the thread instantiation and before the thread start call and still got the same error. I'm getting the notion that I'm going to have to reconsider the design.

    Read the article

  • insert DropDownList and TextField in Gridview

    - by userk
    HI,I need to create a GridView which DataSource is an object. Depending on the object I may need some columns with DropDownLists or TextFields (but not all rows) As I don't know the number or columns, they have to be dynamic. I found this solution: TemplateField t = new TemplateField(); t.HeaderTemplate = new GridViewTemplate("header", "title"); t.ItemTemplate = new GridViewTemplate("combobox", "val"); GridView1.Columns.Add(t); GridView1.DataSource = ds; GridView1.DataBind(); Where GridViewTemplate extends ITemplate. This didn't work for me, it fills all rows of a column and I had no way to control witch DropDownList and TextFields need to be created (object info). All the DropDownLists need to have an ID also only known by the object. There are some way I can do this?

    Read the article

  • Android XML-RPC Serialization Issue

    - by Josh Pennington
    I am attempting to use Android XML-RPC and for some calls I get the following exception: W/System.err( 837): java.io.IOException: Cannot serialize java.lang.Object@43759748 It looks like it is having troubles serializing the returned data, but I cannot find much documentation on how to actually use Android XML-RPC. The way I am using Android XML-RPC is as follows: Object response = (Object)client.call("sales_order.list", new Object()); This one is pretty odd. I have tried setting this call up in a few different ways (using HashMaps, not passing second variable, etc) and the response I get is that sales_order.list is not a valid Method. I have been able to login to the service using the following code: this.sessionId = (String)client.call("login", this.apiUserName, this.apiPassword); Does anyone have any ideas or a good resource on how to use Android XML-RPC? Thanks

    Read the article

  • [Zend Framework] How to format Zend_db Rowset output?

    - by rasouza
    I have a model which is referenced to a table registries extending Zend_Db and some methods which bascially uses fetchAll() all the time. What happens is: my table has a DATE field and I'd like it to output already formated when I call $row-reg_date. Is it possible by doing something in the model or do I have to manually format?

    Read the article

  • How to discover getters and setters on hibernate objects

    - by Michael Jones
    I need to find a way of taking a hibernate object and discovering at runtime all of the getter methods that relate to persistable fields. I'm using annotations in the classes but have previously had difficulties working with them (I ran into a 2 year old bug the java developers still haven't fixed). Does anyone know how I can do this please, ideally without using annotations? Thanks. PS - What I'm trying to do here is to update a new object with values from an existing object dynamically.

    Read the article

  • send and receive in socket [closed]

    - by user3696492
    I have trouble in sending an object through socket in c#, my client can send to server but server can't send to client, i think there is something wrong with the client. Server private void Form1_Load(object sender, EventArgs e) { CheckForIllegalCrossThreadCalls = false; Thread a = new Thread(connect); a.Start(); } private void sendButton_Click(object sender, EventArgs e) { client.Send(SerializeData(ShapeList[ShapeList.Count - 1])); } void connect() { try { server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); iep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 5555); server.Bind(iep); server.Listen(10); client = server.Accept(); while (true) { byte[] data = new byte[1024]; client.Receive(data); PaintObject a = (PaintObject)DeserializeData(data); ShapeList.Add(a); Invalidate(); } } catch (Exception ex) { MessageBox.Show(ex.Message); } } client private void Form1_Load(object sender, EventArgs e) { CheckForIllegalCrossThreadCalls = false; Thread a = new Thread(connect); a.Start(); } private void SendButton_Click(object sender, EventArgs e) { client.Send(SerializeData(ShapeList[ShapeList.Count - 1])); } void connect() { try { client = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); iep = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 5555); client.Connect(iep); while (true) { byte[] data = new byte[1024]; client.Receive(data); PaintObject a = (PaintObject)DeserializeData(data); ShapeList.Add(a); Invalidate(); } } catch (Exception ex) { MessageBox.Show(ex.Message); } }

    Read the article

  • A better name for INeedSomething... ?

    - by Daniel Severin
    I was trying pick a name for an interface through which I can pass something into an object like: If the object is INeedX then SetX(some x) method will be called; If the object is INeedY then SetY(some y) method will be called; and so on. (funny as hell, I know :) ) I try to find a different name for this kind of interfaces but I can't figure this out. Does anybody have an idea how to name the INeedSomething interface ?

    Read the article

  • Cannot implicitly convert type ...

    - by Newbie
    I have the following function public Dictionary<DateTime, object> GetAttributeList( EnumFactorType attributeType ,Thomson.Financial.Vestek.Util.DateRange dateRange) { DateTime startDate = dateRange.StartDate; DateTime endDate = dateRange.EndDate; return (( //Step 1: Iterate over the attribute list and filter the records by // the supplied attribute type from assetAttribute in AttributeCollection where assetAttribute.AttributeType.Equals(attributeType) //Step2:Assign the TimeSeriesData collection into a temporary variable let timeSeriesList = assetAttribute.TimeSeriesData //Step 3: Iterate over the TimeSeriesData list and filter the records by // the supplied date from timeSeries in timeSeriesList.ToList() where timeSeries.Key >= startDate && timeSeries.Key <= endDate //Finally build the needed collection select new AssetAttribute() { TimeSeriesData = PopulateTimeSeriesData(timeSeries.Key, timeSeries.Value) }).ToList<AssetAttribute>().Select(i => i.TimeSeriesData)); } private Dictionary<DateTime, object> PopulateTimeSeriesData(DateTime dateTime, object value) { Dictionary<DateTime, object> timeSeriesData = new Dictionary<DateTime, object>(); timeSeriesData.Add(dateTime, value); return timeSeriesData; } Error:Cannot implicitly convert type 'System.Collections.Generic.IEnumerable' to 'System.Collections.Generic.Dictionary'. An explicit conversion exists (are you missing a cast?) Using C#3.0 Please help

    Read the article

  • What's does "cardinality of an relationship" mean in Core Data?

    - by dontWatchMyProfile
    From the docs: If all of a managed object's relationship delete rules are Nullify, then for that object at least there is no additional work to do (you may have to consider other objects that were at the destination of the relationship—if the inverse relationship was either mandatory or had a lower limit on cardinality, then the destination object or objects might be in an invalid state). Does someone have an example of this cardinality thing? What's this good for and what's important to know about this? (sounds very important...)

    Read the article

  • How do linq Last() work?

    - by acidzombie24
    I dont understand how current can be null and last can be an object while last being a LINQ function. I thought last uses GetEnumerator and keeps going until current == null and returns the object. However as you can see the first GetEnumerator().Current is null and last somehow returns an object. How do linq Last() work? var.GetEnumerator().Current var.Last()

    Read the article

  • Asp.Net MVC How to test that the view rendered

    - by Miau
    HI there I was wondering if there is a better way of testing that a view has rendered in MVC. I was thinking perhaps I should render the view to a string but perhaps there are simpler methods? Basically what I want to know if that the view for a given action has rendered without errors I m already testing the view model but I want to see that rendering the view giving a correct ViewData.Model works

    Read the article

  • How to access image folder in django

    - by anc1revv
    I just started django and i want to access images uploaded by a user. here is my model: class Food(models.Model): name = models.CharField(max_length=100) price = models.DecimalField(max_digits=4, decimal_places=2) quantity = models.IntegerField(blank=True, null=True) description = models.CharField(max_length=200) location = models.CharField(max_length=100) time = models.DateTimeField() photo_thumbnail = models.ImageField(upload_to="images") photo_fullsize = models.ImageField(upload_to="images") i stored the image in the "images" folder below the html is this: img src="{{steak.photo_thumbnail}}" and steak.photo_thumbnail = images/steak_and_egg_thumbnail_1.png here is the error i get: [06/Jul/2012 19:08:24] "GET /menu/ HTTP/1.1" 200 99 [06/Jul/2012 19:08:24] "GET /menu/images/steak_and_egg_thumbnail_1.png HTTP/1.1" 404 2127

    Read the article

  • Crossed import in django

    - by Kuhtraphalji
    On example, i have 2 apps: alpha and beta in alpha/models.py import of model from beta.models and in beta/models.py import of model from alpha.models manage.py validate says that ImportError: cannot import name ModelName how to solve this problem?

    Read the article

  • C++, is it possible to call a constructor directly, without new?

    - by osgx
    Hello Can I call constructor explicitly, without using new, if I already have a memory for object? // class Object1{char *str;public:Object1(char*str):str(str){puts("ctor");puts(str);};~Object1(){puts("dtor");puts(str);}}; Object1 ooo[2] = {Object1("I'm the first object"), Object1("I'm the 2nd")}; do_smth_useful(ooo); ooo[0].~Object1(); // call destructor ooo[0].Object1("I'm the 3rd object in place of first"); // ???? - reuse memory

    Read the article

  • java template design

    - by Sean Nguyen
    Hi, I have this class: public class Converter { private Logger logger = Logger.getLogger(Converter.class); public String convert(String s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); String r = s + "abc"; logger.debug("Output = " + s); return r; } public Integer convert(Integer s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); Integer r = s + 10; logger.debug("Output = " + s); return r; } } The above 2 methods are very similar so I want to create a template to do the similar things and delegate the actual work to the approriate class. But I also want to easily extends this frame work without changing the template. So for example: public class ConverterTemplate { private Logger logger = Logger.getLogger(Converter.class); public Object convert(Object s){ if (s == null) throw new IllegalArgumentException("input can't be null"); logger.debug("Input = " + s); Object r = doConverter(); logger.debug("Output = " + s); return r; } protected abstract Object doConverter(Object arg); } public class MyConverter extends ConverterTemplate { protected String doConverter(String str) { String r = str + "abc"; return r; } protected Integer doConverter(Integer arg) { Integer r = arg + 10; return r; } } But that doesn't work. Can anybody suggest me a better way to do that? I want to achieve 2 goals: 1. A template that is extensible and does all the similar work for me. 2. I ant to minimize the number of extended class. Thanks,

    Read the article

  • problem assigning array to variable

    - by shaw2thefloor
    Hi. I'm sure this is a simple one. I have an array in a simplexml object. When I try to assign the array to a variable, it only assigns the first index of the array. How can I get it to assign the whole array. This is my code. $xml = simplexml_load_string(FlickrUtils::getMyPhotos("flickr.photos.search", $_SESSION['token'])); $photosArray = $xml->photos; //$photosArray = $xml->photos->photo; //echo gettype($photosArray); print_r($photosArray); This is the result of the print_r($photosArray); SimpleXMLElement Object ( [@attributes] = Array ( [page] = 1 [pages] = 1 [perpage] = 100 [total] = 4 ) [photo] => Array ( [0] => SimpleXMLElement Object ( [@attributes] => Array ( [id] => 5335626037 [owner] => 57991585@N02 [secret] => bd66f06b49 [server] => 5210 [farm] => 6 [title] => 1 [ispublic] => 1 [isfriend] => 0 [isfamily] => 0 ) ) [1] => SimpleXMLElement Object ( [@attributes] => Array ( [id] => 5336238676 [owner] => 57991585@N02 [secret] => 898dffa011 [server] => 5286 [farm] => 6 [title] => 2 [ispublic] => 1 [isfriend] => 0 [isfamily] => 0 ) ) [2] => SimpleXMLElement Object ( [@attributes] => Array ( [id] => 5335625381 [owner] => 57991585@N02 [secret] => 60a0c84597 [server] => 5126 [farm] => 6 [title] => 4 [ispublic] => 1 [isfriend] => 0 [isfamily] => 0 ) ) [3] => SimpleXMLElement Object ( [@attributes] => Array ( [id] => 5335625195 [owner] => 57991585@N02 [secret] => 49348c1e8b [server] => 5126 [farm] => 6 [title] => 3 [ispublic] => 1 [isfriend] => 0 [isfamily] => 0 ) ) ) ) Thanks for youe help!

    Read the article

  • Django: select_related and GenericRelation

    - by Parand
    Does select_related work for GenericRelation relations, or is there a reasonable alternative? At the moment Django's doing individual sql calls for each item in my queryset, and I'd like to avoid that using something like select_related. class Claim(models.Model): proof = generic.GenericRelation(Proof) class Proof(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') I'm selecting a bunch of Claims, and I'd like the related Proofs to be pulled in instead of queried individually.

    Read the article

  • Using intermediate array for hashCode and equals

    - by Basilevs
    As its a pain to handle structural changes of the class in two places I often do: class A { private B bChild; private C cChild; private Object[] structure() { return new Object[]{bChild, cChild}; } int hashCode() { Arrays.hashCode(structure); } boolean equals(Object that) { return Arrays.equals(this.structure(), ((A)that).structure()); } } What's bad about this approach besides boxing of primitives? Can it be improved?

    Read the article

  • How to save link with tag e parameters in TextField

    - by xRobot
    I have this simple Post model: class Post(models.Model): title = models.CharField(_('title'), max_length=60, blank=True, null=True) body = models.TextField(_('body')) blog = models.ForeignKey(Blog, related_name="posts") user = models.ForeignKey(User) I want that when I insert in the form the links, the these links are saved in the body from this form: http://www.example.com or www.example.com to this form ( with tag and rel="nofollow" parameter ): <a href="http://www.example.com" rel="nofollow">www.example.com</a> How can I do this ? Thanks ^_^

    Read the article

  • C++ String pointers

    - by gnm
    In my previous app I had an object like this: class myType { public: int a; string b; } It had a lot of instances scattered everywhere and passed around to nearly every function. The app was slow. Profiling said that 95% of time is eaten by the string allocator function. I know how to work with the object above, but not how to work with string pointers. class myType { public: int a; string* b; } They told me to use pointers as above. How much faster is it with a string pointer? What is copied when I copy the object? How to the following using the class with the pointer: Access the string value Modify the string value without modifying the one in the object (copy?) General things that change if I use string pointers?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 468 469 470 471 472 473 474 475 476 477 478 479  | Next Page >