Search Results

Search found 11306 results on 453 pages for 'methods'.

Page 347/453 | < Previous Page | 343 344 345 346 347 348 349 350 351 352 353 354 | Next Page >

Trouble parsing quotes with SAX parser (javax.xml.parsers.SAXParser)

- by johnrock

When using a SAX parser, parsing fails when there is a " in the node content. How can I resolve this? Do I need to convert all " characters? In other words, anytime I have a quote in a node: <node>characters in node containing "quotes"</node> That node gets butchered into multiple character arrays when the Handler is parsing it. Is this normal behaviour? Why should quotes cause such a problem? Here is the code I am using: import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpGet; import org.xml.sax.InputSource; import org.xml.sax.XMLReader; ... HttpGet httpget = new HttpGet(GATEWAY_URL + "/"+ question.getId()); httpget.setHeader("User-Agent", PayloadService.userAgent); httpget.setHeader("Content-Type", "application/xml"); HttpResponse response = PayloadService.getHttpclient().execute(httpget); HttpEntity entity = response.getEntity(); if(entity != null) { SAXParserFactory spf = SAXParserFactory.newInstance(); SAXParser sp = spf.newSAXParser(); XMLReader xr = sp.getXMLReader(); ConvoHandler convoHandler = new ConvoHandler(); xr.setContentHandler(convoHandler); xr.parse(new InputSource(entity.getContent())); entity.consumeContent(); messageList = convoHandler.getMessageList(); }

Read the article
Add new types to Go

- by nevalu

I'm trying add new types for that been managed/used as in Go core types. To create new types is anything very interesting to validate data before of send it to a non-SQL DBMS or to check data from a form. Go uses univeral constants to define them at global level: var DateType = universe.DefineType("date", universePos, &dateType{}) In this case they're defined to be called from a package like types: var Date = &dateType{} I get these errors: test.go:58: o.lit undefined (cannot refer to unexported field lit) test.go:62: *dateType is not Type missing Pos() token.Position The code is based on: http://github.com/tav/go/blob/master/src/pkg/exp/eval/value.go http://github.com/tav/go/blob/master/src/pkg/exp/eval/type.go package main import ( "exp/eval" "fmt" // "go/token" ) // http://github.com/tav/go/blob/master/src/pkg/exp/eval/value.go type DateValue interface { eval.Value Get(*eval.Thread) string Set(*eval.Thread, string) } /* Date */ type dateV string func (v *dateV) String() string { return fmt.Sprint(*v) } func (v *dateV) Assign(t *eval.Thread, o eval.Value) { *v = dateV(o.(DateValue).Get(t)) } func (v *dateV) Get(*eval.Thread) string { return string(*v) } func (v *dateV) Set(t *eval.Thread, x string) { *v = dateV(x) } // http://github.com/tav/go/blob/master/src/pkg/exp/eval/type.go type Type interface { eval.Type // isDate returns true if this is a date type. isDate() bool } /* Common type */ type commonType struct{} // added func (commonType) isDate() bool { return false } /* Date */ type dateType struct { commonType } // * It should not be an universal constant //var universePos = token.Position{"<universe>", 0, 0, 0} // added //var DateType = universe.DefineType("date", universePos, &dateType{}) var Date = &dateType{} func (t *dateType) compat(o Type, conv bool) bool { t2, ok := o.lit().(*dateType) return ok && t == t2 } func (t *dateType) lit() Type { return t } func (t *dateType) isDate() bool { return true } func (t *dateType) String() string { return "<date>" } func (t *dateType) Zero() eval.Value { res := dateV("") return &res } /* Named types */ /* type NamedType struct { eval.NamedType Def Type }*/ type NamedType struct { // added // token.Position Name string // Underlying type. If incomplete is true, this will be nil. // If incomplete is false and this is still nil, then this is // a placeholder type representing an error. Def Type // True while this type is being defined. incomplete bool methods map[string]eval.Method } func (t *NamedType) isDate() bool { return t.Def.isDate() } /* *********************** */ func main() { print("foo") }

Read the article
Efficient data importing?

- by Kevin

We work with a lot of real estate, and while rearchitecting how the data is imported, I came across an interesting issue. Firstly, the way our system works (loosely speaking) is we run a Coldfusion process once a day that retrieves data provided from an IDX vendor via FTP. They push the data to us. Whatever they send us is what we get. Over the years, this has proven to be rather unstable. I am rearchitecting it with PHP on the RETS standard, which uses SOAP methods of retrieving data, which is already proven to be much better than what we had. When it comes to 'updating' existing data, my initial thought was to query only for data that was updated. There is a field for 'Modified' that tells you when a listing was last updated, and the code I have will grab any listing updated within the last 6 hours (give myself a window in case something goes wrong). However, I see a lot of real estate developers suggest creating 'batch' processes that run through all listings regardless of updated status that is constantly running. Is this the better way to do it? Or am I fine with just grabbing the data I know I need? It doesn't make a lot of sense to me to do more processing than necessary. Thoughts?

Read the article
Best emailing approach with template emails

- by Harun Baris Bulut

Hi all, We are creating a project with lots of different mail templates in it. There are different messages for different purposes and we are trying to make the coding easy and understandable for the future. By the way we have different transport classes like e-mail, sms, twitter vs... Now we are doing this but I dont know if there is a better solution. We have a class called H2B_Message_Container_Mail_About_Blablabla it has 4 methods; interface H2B_Message_Mail_Interface { public function setName($name); public function setValue($key, $value); public function getMailBody(); public function getMailSubject(); } and in the mail body there are various variables as expected. before we send the mail, we get the variable values from the database with JSON format and decode it. Then we send it like; $mail = new H2B_Message_Mail(); $mail->setTemplate($newTemplate); $mail->send(); The question is; is there a better way to do this ?

Read the article
How does a java web project architecture look like without EJB3 ?

- by Hendrik

A friend and I are building a fairly complex website based on java. (PHP would have been more obvious but we chose for java because the educational aspect of this project is important to us) We have already decided to use JSF (with richfaces) for the front end and JPA for the backend and so far we have decided not to use EJB3 for the business layer. The reason we've decided not to use EJB3 is because - and please correct me if I am wrong - if we use EJB3 we can only run it on a full blown java application server like jboss and if we don't use EJB3 we can still run it on a lightweight server like tomcat. We want to keep speed and cost of our future web server in mind. So far i've worked on two JEE projects and both used the full stack with web business logic factories/persistence service entities with every layer a seperate module. Now here is my question, if you dont use EJB3 in the business logic layer. What does the layer look like? Please tell what is common practice when developing java web projects without ejb3? Do you think business logic layer can be thrown out altogether and have business logic in the backing beans? If you keep the layer, do you have all business methods static? Or do you initialize each business class as needed in the backing beans in every session as needed?

Read the article
Use the repository pattern when using PLINQO generated data?

- by Chad

I'm "upgrading" an MVC app. Previously, the DAL was a part of the Model, as a series of repositories (based on the entity name) using standard LINQ to SQL queries. Now, it's a separate project and is generated using PLINQO. Since PLINQO generates query extensions based on the properties of the entity, I started using them directly in my controller... and eliminated the repositories all together. It's working fine, this is more a question to draw upon your experience, should I continue down this path or should I rebuild the repositories (using PLINQO as the DAL within the repository files)? One benefit of just using the PLINQO generated data context is that when I need DB access, I just make one reference to the the data context. Under the repository pattern, I had to reference each repository when I needed data access, sometimes needing to reference multiple repositories on a single controller. The big benefit I saw on the repositories, were aptly named query methods (i.e. FindAllProductsByCategoryId(int id), etc...). With the PLINQO code, it's _db.Product.ByCatId(int id) - which isn't too bad either. I like both, but where it gets "harrier" is when the query uses predicates. I can roll that up into the repository query method. But on the PLINQO code, it would be something like _db.Product.Where(x = x.CatId == 1 && x.OrderId == 1); I'm not so sure I like having code like that in my controllers. Whats your take on this?

Read the article
Abort SAX parsing mid-document?

- by CSharperWithJava

I'm parsing a very simple XML schema with a SAX parser in Android. An example file would be <Lists> <List name="foo"> <Note title="note 1" .../> <Note title="note 2" .../> </List> <List name="bar"> <Note title="note 3" .../> </List> </Lists> The ... represents more note data as attributes that aren't important to question. I use a SAX parser to parse the document and only implement the startElement and 'endElement' methods of the HandlerBase to handle Note and List nodes. However, In some cases the files can be very large and take some time to process. I'd like to be able to abort the parsing process at any time (i.e. user presses cancel button). The best way I've come up with is to throw an exception from my startElement method when certain conditions are met (i.e. boolean stopParsing is true). Is there a better way to do this? I've always used DOM style parsers, so I don't fully understand the SAX parser. One final note, I'm running this on Android, so I will have the Parser running on a worker thread to keep the UI responsive. If you know how I can kill the thread safely while the parser is running that would answer my question as well.

Read the article
Modifying UINavigation Bar Buttons in SubViews

- by james

I'm having trouble trying to modify the navigation bar in the subview portion of my application. self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(add_Clicked:)] autorelease]; I have no issues modifying the navigation bar in any of my UIViewControllers classes. The simplified application class outline is as such: AppDelegate - UIViewControllerA (has a left and a right navigationBarButton) - Subview is displayed when a SegmentControl is selected. (Within the subview, I'm trying to modify the right NavigationBarButton that is displayed) [self.view addSubview:newControllerName.view]; Methods I have attempted: Trying to set self.navigationItem.rightBarButtonItem within my subview to a new UIBarButtonItem. Creating a pointer to UIViewControllerA within my AppDelegate. The UIViewControllerA contains a function setNavButton I wrote to set the rightBarButtonItem to a button. Then I am referencing the AppDelegate's reference to UIViewControllerA and attempting to call setNavButton. I included a NSLog call to see if that function is being called and it is executing but the NavigationBar isn't being modified. I'm trying to avoid having to push a UIViewController after the SegmentControl is clicked in UIViewControllerA so that I can simulate the SegmentControl as tabs. I'm not getting any errors during compile or run time. Anyone have any ideas?

Read the article
Windows Azure ASP.NET MVC Role behaves strangely when redirecting from HTTP to HTTPS

- by Rinat Abdullin

Subj. I've got an ASP.NET 2 MVC Worker Role Application, that does not differ much from the default template. When attempting redirect from HTTP to HTTPS (this happens when we access constroller secured by the usual RequireSSL attribute implementation) we get blank page with "Bad Request" message. IntelliTrace shows this: Thrown: "The file '/Views/Home/LogOnUserControl.aspx' does not exist." (System.Web.HttpException) Call stack is really short: [External Code] App_Web_vfahw7gz.dll!ASP.views_shared_site_master.__Render__control1(System.Web.UI.HtmlTextWriter __w = {unknown}, System.Web.UI.Control parameterContainer = {unknown}) [External Code] App_Web_bsbqxr44.dll!ASP.views_home_index_aspx.ProcessRequest(System.Web.HttpContext context = {unknown}) [External Code] User control reference is the usual one in /Views/Shared/Site.Master: <div id="logindisplay"> <% Html.RenderPartial("LogOnUserControl"); %> </div> And partial view LogOnUserControl.ashx is located in Views/Shared (and it is ASHX, not ASPX). Problem shows up, when we try to access site pages, that require auth and redirect. These pages are secured by RequireSSL attribute (Redirect == true): [AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, Inherited = true, AllowMultiple = false)] public sealed class RequireSslAttribute : FilterAttribute, IAuthorizationFilter { public bool Redirect { get; set; } // Methods public void OnAuthorization(AuthorizationContext filterContext) { // this get's messy, when we are running custom ports // within the local dev fabric. // hence we disable code in the debug #if !DEBUG if (filterContext == null) { throw new ArgumentNullException("filterContext"); } if (filterContext.HttpContext.Request.IsSecureConnection) return; var canRedirect = string.Equals(filterContext.HttpContext.Request.HttpMethod, "GET", StringComparison.OrdinalIgnoreCase); if (canRedirect && Redirect) { var builder = new UriBuilder { Scheme = "https", Host = filterContext.HttpContext.Request.Url.Host, Path = filterContext.HttpContext.Request.RawUrl }; filterContext.Result = new RedirectResult(builder.ToString()); } else { throw new HttpException(0x193, "Access forbidden. The requested resource requires an SSL connection."); } #endif } } Obviously we compile in RELEASE for this case. Does anybody have any idea, what could cause this strange exception and how to get rid of it?

Read the article
Worklight client-side API to overrideBackButton doesn't work

- by user2503429

I want to make something happen when back button is pressed so I put this code in Myhtml.js file : function wlCommonInit(){ /* * Application is started in offline mode as defined by a connectOnStartup property in initOptions.js file. * In order to begin communicating with Worklight Server you need to either: * * 1. Change connectOnStartup property in initOptions.js to true. * This will make Worklight framework automatically attempt to connect to Worklight Server as a part of application start-up. * Keep in mind - this may increase application start-up time. * * 2. Use WL.Client.connect() API once connectivity to a Worklight Server is required. * This API needs to be called only once, before any other WL.Client methods that communicate with the Worklight Server. * Don't forget to specify and implement onSuccess and onFailure callback functions for WL.Client.connect(), e.g: * * WL.Client.connect({ * onSuccess: onConnectSuccess, * onFailure: onConnectFailure * }); * */ // Common initialization code goes here } WL.App.overrideBackButton(backFunc); function backFunc(){ alert('You will back to previous page'); } but after build and deploy the app and I running it, nothing happened after I pressed back button, anybody have the solution ?

Read the article
Java inheritance question

- by Milos

I have an abstract class Airplane, and two classes PassengerAirplane and CargoAirplane, which extend class Airplane. I also have an interface Measurable, and two classes that implement it - People and Containers. So, Airplane can do many things on its own, and there is a method which allows measurable things to be added to the airplane (called addAMeasurableThing). The only difference between PassengerAirplane/CargoAirplane and just an Airplane is that addAMeasurableThing should only accept People / Containers, and not any kind Measurable things. How do I implement this? I tried doing: Airplane class: public abstract Airplane addAMeasurableThing (Measurable m, int position); PassengerAirplane class: public Airplane addAMeasurableThing (Measurable m, int position) { if (m instanceof People)... CargoAirplane class: public Airplane addAMeasurableThing (Measurable m, int position) { if (m instanceof Containers)... But when I was debugging it, I've noticed that addAMeasurableThing in the CargoAirplane class never gets called, because both methods have the same signature. So how can the appropriate PassengerAirplane/CargoAirplane's addAMeasurableThing be called, depending on the type of Measurable thing that is being passed on? Thanks!

Read the article
what is wrong in java AES decrypt function?

- by rohit

hi, i modified the code available on http://java.sun.com/developer/technicalArticles/Security/AES/AES_v1.html and made encrypt and decrypt methods in program. but i am getting BadpaddingException.. also the function is returning null.. why it is happing?? whats going wrong? please help me.. these are variables i am using: kgen = KeyGenerator.getInstance("AES"); kgen.init(128); raw = new byte[]{(byte)0x00,(byte)0x11,(byte)0x22,(byte)0x33,(byte)0x44,(byte)0x55,(byte)0x66,(byte)0x77,(byte)0x88,(byte)0x99,(byte)0xaa,(byte)0xbb,(byte)0xcc,(byte)0xdd,(byte)0xee,(byte)0xff}; skeySpec = new SecretKeySpec(raw, "AES"); cipher = Cipher.getInstance("AES"); plainText=null; cipherText=null; following is decrypt function.. public String decrypt(String cipherText) { try { cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] original = cipher.doFinal(cipherText.getBytes()); plainText = new String(original); } catch(BadPaddingException e) { } return plainText; }

Read the article
Is this a tableView issue or a CoreData Issue

- by monotreme

I have a CoreData-driven navigation app and I'm trying to figure out why It's crashing. I've got a hierarchy which is 3 view Controllers deep, all related by coredata relatioships, like this. TableViewA =relationship= TableViewB =relationship= TableViewC I'm honestly a novice at core data and I think my problem lies in the fetched results controller. I have one in TableViewA and another in TableViewB, and no matter how deep I go, the console always cites TableViewB's fetched results controller methods after a crash. Is this the problem? What's happening specifically is if I launch my app and drill down into the hierarchy of one record, let's call it Record1, I can delete sub records to my hearts content. Gone! no problem! But the second I go back to TableViewA and drill down into a different record, let's call that one Record2, and try to delete it's subrecords my app crashes, with the console citing this code from TableViewB as the problem. - (void)controllerWillChangeContent:(NSFetchedResultsController *)controller { // The fetch controller is about to start sending change notifications, so prepare the table view for updates. [self.tableView beginUpdates]; } When I go into the debugger, the specific method it always has a problem with is: if (![x.managedObjectContext save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } Just a confirmation of my idiocy with CoreData is all I'm looking for I think. Oh and how many ManagedObjectContexts should I have in an app of this type. I've been told I should have separate ones for adding content, which then should re-integrate into the main one. Is this true? Thanks!

Read the article
Query eror handling in CodeIgniter

- by Sajith S Narayanan

Hi All, I am trying to execute an MySql query using the CI Active methods. If the query is malformed, then CI invokes internal server error 500 and quits without processing the next steps.. I need to roll back all the other queries processed before that error statement, and the roll back is also not happening.. can you help pls. The code snippets is as below: function dbInsertInformationToDB($data_array) { $returnID = ""; $uniqueDataArray = array(); // I prepare a array of values here $uniqueTableList = filter_unique_tables($data_array[2]); $this->db->trans_begin(); // inserting is done here // when there is a query error in $this->db->insert().. it is not rolling back the previous query executed foreach($uniqueTableList as $table_name) { $uniqueDataArray = filterDataArray($data_array,$table_name,2); $this->db->insert($table_name,$uniqueDataArray); if ($this->db->_error_message()) { $error = "I am caught!!"; } $returnID = $this->db->affected_rows(); } if ($this->db->trans_status() === FALSE) { $this->db->trans_rollback(); } else { $this->db->trans_commit(); } return "ERROR"; }

Read the article
Rewrite arrays using collections

- by owca

I have a task, which I was able to do with the use of simplest methods - arrays. Now I'd like to go further and redo it using some more complicated java features like collections, but I've never used anything more complicated than 2d matrix. What should I look at and how to start with it. Should Tower become a Collection ? And here's the task : We have two classes - Tower and Block. Towers are built from Blocks. Ande here's sample code for testing: Block k1=new Block("yellow",1,5,4); Block k2=new Block("blue",2,2,6); Block k3=new Block("green",3,4,2); Block k4=new Block("yellow",1,5,4); Tower tower=new Tower(); tower.add(k1,k2,k3); "Added 3 blocks." System.out.println(tower); "block: green, base: 4cm x 3cm, thicknes: 2 cm block: blue, base: 6cm x 2cm, thicknes: 2 cm block: yellow, base: 5cm x 4cm, thicknes: 1 cm" tower.add(k2); "Tower already contains this block." tower.add(k4); "Added 1 block." System.out.println(tower); "block: green, base: 4cm x 3cm, thicknes: 2 cm block: blue, base: 6cm x 2cm, thicknes: 2 cm block: yellow, base: 5cm x 4cm, thicknes: 1 cm block: yellow, base: 5cm x 4cm, thicknes: 1 cm" tower.delete(k1); "Deleted 1 block" tower.delete(k1); "Block not in tower" System.out.println(tower); "block: blue, base: 6cm x 2cm, thicknes: 2 cm block: yellow, base: 5cm x 4cm, thicknes: 1 cm block: yellow, base: 5cm x 4cm, thicknes: 1 cm" Let's say I will treat Tower as a collection of blocks. How to perform search for specific block among whole collection ? Or should I use other interface ?

Read the article
Object created in Interface Builder getting dealloc'ed too soon

- by Collin Allen

The Project I'm working on a relatively simple iPhone OS project that's navigation controller based, with a root table view and a detail table view. Tap an item in the main list to see its details in a pushed table view. The Setup I broke out the data source for both views into their own objects so as not to muddy the purpose of a view controller. Having done this, the table views no longer have data sources since those methods are now in separate files, so I created an instance of each data source class in the appropriate XIB files with the Object item (dragged it in, then set its class). Then, to actually connect the tableviews to their data sources, I set the dataSource outlet of each tableview to the yellow data source object in Interface Builder. The table view delegates are still set to their view controllers. The Problem The root table view works just fine, but when you tap a row to push to the detail view, the data source object gets instantiated as expected, then immediately dealloc'ed, causing a crash (numberOfSectionsInTableView: gets called on the freed object). I can't figure out why the data source is getting automatically dealloc-ed when I need it right then and there for the detail view, as indicated by my data source object creation and tableview connection in Interface Builder. What's more perplexing is that the very approach works fine for the root tableview! The Question Is there anything obvious I'm missing that would cause this to happen? Or, is this even the right way to instantiate a data source for a table view controller? It seems like poor object oriented programming to do it from within the view controller, which should only be concerned with the view. I could cram everything in two table view controller classes and it would probably work, but it would not be as modular as I'd like. Thanks!

Read the article
Interface and partial classes

- by Tomek Tarczynski

According to rule SA1201 in StyleCop elements in class must appear in correct order. The order is following: Fields Constructors Finalizers (Destructors) Delegates Events Enums Interfaces Properties Indexers Methods Structs Classes Everything is ok, except of Interfaces part, because Interface can contain mehtods, events, properties etc... If we want to be strict about this rule then we won't have all members of Interface in one place which is often very useful. According to StyleCop help this problem can be solved by spliting class into partial classes. Example: /// <summary> /// Represents a customer of the system. /// </summary> public partial class Customer { // Contains the main functionality of the class. } /// <content> /// Implements the ICollection class. /// </content> public partial class Customer : ICollection { public int Count { get { return this.count; } } public bool IsSynchronized { get { return false; } } public object SyncRoot { get { return null; } } public void CopyTo(Array array, int index) { throw new NotImplementedException(); } } Are there any other good solutions to this problem?

Read the article
Efficient cron job utilizing Zend_Mail_Storage_Imap.

- by fireeyedboy

I'm new to the IMAP protocol and Zend_Mail_Storage and I'm writing a small php script for a cron job that should regularly poll an IMAP account and check for new messages, and send an e-mail if new messages have arrived. As you can imagine, I want to only poll the IMAP account for relevant messages, and I only want to send a new e-mail if new messages have arrived since the last polled new message. So I thought of keeping track of the last message I polled with some unique identifier for a message. But I'm a bit uncertain about whether the methods I want to utilize for this do what I expect them to do though. So my questions are: Does the iterator position of Zend_Mail_Storage_Imap actually resemble some IMAP unique identifier for messages, or is it simply only and internal position of Zend_Mail_Storage_Abstract? For instance, if I tell it to seek() to message 5 (which I stored from an earlier session) will it indeed seek to the appropriate message on the IMAP server, even if for instance messages have been deleted since last session? Would keeping track of this latest polled message id in a file suffice for a cron job that, say, polls the account every 5 or 10 minutes? Or is this too naive, and should I be using a database for instance. Or is there maybe a much easier way to keep track of such state with Zend_Mail_Storage_Abstract? Also, do I need to poll every IMAP folder? Or is everything accumulated when I poll INBOX? If you could shed some light on any of these matters, I'ld appreciate it. Thanks in advance.

Read the article
List of objects or parallel arrays of properties?

- by Headcrab

The question is, basically: what would be more preferable, both performance-wise and design-wise - to have a list of objects of a Python class or to have several lists of numerical properties? I am writing some sort of a scientific simulation which involves a rather large system of interacting particles. For simplicity, let's say we have a set of balls bouncing inside a box so each ball has a number of numerical properties, like x-y-z-coordinates, diameter, mass, velocity vector and so on. How to store the system better? Two major options I can think of are: to make a class "Ball" with those properties and some methods, then store a list of objects of the class, e. g. [b1, b2, b3, ...bn, ...], where for each bn we can access bn.x, bn.y, bn.mass and so on; to make an array of numbers for each property, then for each i-th "ball" we can access it's 'x' coordinate as xs[i], 'y' coordinate as ys[i], 'mass' as masses[i] and so on; To me it seems that the first option represents a better design. The second option looks somewhat uglier, but might be better in terms of performance, and it could be easier to use it with numpy and scipy, which I try to use as much as I can. I am still not sure if Python will be fast enough, so it may be necessary to rewrite it in C++ or something, after initial prototyping in Python. Would the choice of data representation be different for C/C++? What about a hybrid approach, e.g. Python with C++ extension?

Read the article
Why can't perfmon see instances of my custom performance counter?

- by spoulson

I'm creating some custom performance counters for an application. I wrote a simple C# tool to create the categories and counters. For example, the code snippet below is basically what I'm running. Then, I run a separate app that endlessly refreshes the raw value of the counter. While that runs, the counter and dummy instance are seen locally in perfmon. The problem I'm having is that the monitoring system we use can't see the instances in the multi-instance counter I've created when viewing remotely from another server. When using perfmon to browse the counters, I can see the category and counters, but the instances box is grayed out and I can't even select "All instances", nor can I click "Add". Using other access methods, like [typeperf][1] exhibit similar issues. I'm not sure if this is a server or code issue. This is only reproducible in the production environment where I need it. On my desktop and development servers, it works great. I'm a local admin on all servers. CounterCreationDataCollection collection = new CounterCreationDataCollection(); var category_name = "My Application"; var counter_name = "My counter name"; CounterCreationData ccd = new CounterCreationData(); ccd.CounterType = PerformanceCounterType.RateOfCountsPerSecond64; ccd.CounterName = counter_name; ccd.CounterHelp = counter_name; collection.Add(ccd); PerformanceCounterCategory.Create(category_name, category_name, PerformanceCounterCategoryType.MultiInstance, collection); Then, in a separate app, I run this to generate dummy instance data: var pc = new PerformanceCounter(category_name, counter_name, instance_name, false); while (true) { pc.RawValue = 0; Thread.Sleep(1000); }

Read the article
MySQL-python 1.2.3 and OS X 10.5: 64- or 32-bit?

- by Dave Everitt

I've been happily using Django and MySQL in development on an existing machine running OS X 10.4 Tiger, and have set up a similar environment in 10.5 Leopard on a new 64-bit MacBook, with a working MySQL and Python 2.6.4. However, now I want them to communicate, easy_install MySQL-python gave ld warnings that the file is not of the required architecture, which led me to test my Python 2.4.6 install (from the Mac OS X disc image): >>> import sys >>> sys.maxint 2147483647 Ah. So my Python install appears to be 32-bit and (I think?) won't install MySQL-python for my 64-bit MySQL. There are lots of hacks out there for MySQL-python on OS X (mostly 1.2.2), but - after hours of reading - I'm pretty sure they won't fix this architecture mismatch. So I'm stuck because I can't decide whether to: give up, remove the 64-bit MySQL install (thorough methods, please?) and use the 32-bit MySQL disc image instead; re-install Python in 64-bit mode from the tarball, --with-universal archs-64-bit and --enable-universalsdk= as detailed in Python.org's 2.6 news. So my questions for anyone who has encountered this issue are: Is installing 64-bit Python on OS X 10.5 worth bothering with? If so, (naive, lazy question!) how are the two required arguments combined? If I just skip along in 32-bit (as on my working setup) what am I missing? I'm after a hassle-free install that's easy to reproduce on other machines (possible student use) so I'd really welcome your opinions, please!

Read the article
CPU friendly infinite loop

- by Adi

Writing an infinite loop is simple: while(true){ //add whatever break condition here } But this will trash the CPU performance. This execution thread will take as much as possible from CPU's power. What is the best way to lower the impact on CPU? Adding some Thread.Sleep(n) should do the trick, but setting a high timeout value for Sleep() method may indicate an unresponsive application to the operating system. Let's say I need to perform a task each minute or so in a console app. I need to keep Main() running in an "infinite loop" while a timer will fire the event that will do the job. I would like to keep Main() with the lowest impact on CPU. What methods do you suggest. Sleep() can be ok, but as I already mentioned, this might indicate an unresponsive thread to the operating system. LATER EDIT: I want to explain better what I am looking for: I need a console app not Windows service. Console apps can simulate the Windows services on Windows Mobile 6.x systems with Compact Framework. I need a way to keep the app alive as long as the Windows Mobile device is running. We all know that the console app runs as long as its static Main() function runs, so I need a way to prevent Main() function exit. In special situations (like: updating the app), I need to request the app to stop, so I need to infinitely loop and test for some exit condition. For example, this is why Console.ReadLine() is no use for me. There is no exit condition check. Regarding the above, I still want Main() function as resource friendly as possible. Let asside the fingerprint of the function that checks for the exit condition.

Read the article
Handling incremental Data Modeling Changes in Functional Programming

- by Adam Gent

Most of the problems I have to solve in my job as a developer have to do with data modeling. For example in a OOP Web Application world I often have to change the data properties that are in a object to meet new requirements. If I'm lucky I don't even need to programmatically add new "behavior" code (functions,methods). Instead I can declarative add validation and even UI options by annotating the property (Java). In Functional Programming it seems that adding new data properties requires lots of code changes because of pattern matching and data constructors (Haskell, ML). How do I minimize this problem? This seems to be a recognized problem as Xavier Leroy states nicely on page 24 of "Objects and Classes vs. Modules" - To summarize for those that don't have a PostScript viewer it basically says FP languages are better than OOP languages for adding new behavior over data objects but OOP languages are better for adding new data objects/properties. Are there any design pattern used in FP languages to help mitigate this problem? I have read Phillip Wadler's recommendation of using Monads to help this modularity problem but I'm not sure I understand how?

Read the article
Learning Hibernate: too many connections

- by stivlo

I'm trying to learn Hibernate and I wrote the simplest Person Entity and I was trying to insert 2000 of them. I know I'm using deprecated methods, I will try to figure out what are the new ones later. First, here is the class Person: @Entity public class Person { private int id; private String name; @Id @GeneratedValue(strategy = GenerationType.TABLE, generator = "person") @TableGenerator(name = "person", table = "sequences", allocationSize = 1) public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } } Then I wrote a small App class that insert 2000 entities with a loop: public class App { private static AnnotationConfiguration config; public static void insertPerson() { SessionFactory factory = config.buildSessionFactory(); Session session = factory.getCurrentSession(); session.beginTransaction(); Person aPerson = new Person(); aPerson.setName("John"); session.save(aPerson); session.getTransaction().commit(); } public static void main(String[] args) { config = new AnnotationConfiguration(); config.addAnnotatedClass(Person.class); config.configure("hibernate.cfg.xml"); //is the default already new SchemaExport(config).create(true, true); //print and execute for (int i = 0; i < 2000; i++) { insertPerson(); } } } What I get after a while is: Exception in thread "main" org.hibernate.exception.JDBCConnectionException: Cannot open connection Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Too many connections Now I know that probably if I put the transaction outside the loop it would work, but mine was a test to see what happens when executing multiple transactions. And since there is only one open at each time, it should work. I tried to add session.close() after the commit, but I got Exception in thread "main" org.hibernate.SessionException: Session was already closed So how to solve the problem?

Read the article
How is it that json serialization is so much faster than yaml serialization in python?

- by guidoism

I have code that relies heavily on yaml for cross-language serialization and while working on speeding some stuff up I noticed that yaml was insanely slow compared to other serialization methods (e.g., pickle, json). So what really blows my mind is that json is so much faster that yaml when the output is nearly identical. >>> import yaml, cjson; d={'foo': {'bar': 1}} >>> yaml.dump(d, Dumper=yaml.SafeDumper) 'foo: {bar: 1}\n' >>> cjson.encode(d) '{"foo": {"bar": 1}}' >>> import yaml, cjson; >>> timeit("yaml.dump(d, Dumper=yaml.SafeDumper)", setup="import yaml; d={'foo': {'bar': 1}}", number=10000) 44.506911039352417 >>> timeit("yaml.dump(d, Dumper=yaml.CSafeDumper)", setup="import yaml; d={'foo': {'bar': 1}}", number=10000) 16.852826118469238 >>> timeit("cjson.encode(d)", setup="import cjson; d={'foo': {'bar': 1}}", number=10000) 0.073784112930297852 PyYaml's CSafeDumper and cjson are both written in C so it's not like this is a C vs Python speed issue. I've even added some random data to it to see if cjson is doing any caching, but it's still way faster than PyYaml. I realize that yaml is a superset of json, but how could the yaml serializer be 2 orders of magnitude slower with such simple input?

Read the article

< Previous Page | 343 344 345 346 347 348 349 350 351 352 353 354 | Next Page >