Search Results

Search found 5705 results on 229 pages for 'observer pattern'.

Page 170/229 | < Previous Page | 166 167 168 169 170 171 172 173 174 175 176 177  | Next Page >

• What is a good architecture for a Lift-JPA application?

  - by egervari

  I was wondering what is the best practice for a JPA model in Lift? I noticed that in the jpa demo application, there is just a Model object that is like a super object that does everything. I don't think this can be the most scalable approach, no? Is it is wise to still do the DAO pattern in Lift? For example, there's some code that looks a tad bloated and could be simplified across all model objects: Model.remove(Model.getReference(classOf[Author], someId)) Could be: AuthorDao.remove(someId) I'd appreciate any tips for setting up something that will work with the way Lift wants to work and is also easy to organize and maintain. Preferably from someone who has actually used JPA on a medium to large Lift site rather than just postulating what Spring does (we know how to do that) ;) The first phase of development will be around 30-40 tables, and will eventually get to over 100... we need a scalable, neat approach.

  Read the article

• asynchronous calls in asp.net

  - by lockedscope

  in this sample, two threads created; a worker thread created by BeginInvoke and an I/O completion thread created by SendAsync method. but another author in his UnsafeQueueNativeOverlapped example, don't recommend this. i want to use SendAsync or ...Async in an asp.net page and i want to use PageAsyncTask. however, its BeginEventHandler requires AsyncResult to be returned which SendAsync does not return. afaik, event based async pattern is the most recommended way so how could we call SendAsync or any ...Async methods without creating two threads and hurting the performance?

  Read the article

• How to synchronize static method in java.

  - by Summer_More_More_Tea

  Hi there: I come up with this question when implementing singleton pattern in Java. Even though the example listed blow is not my real code, yet very similar to the original one. public class ConnectionFactory{ private static ConnectionFactory instance; public static synchronized ConnectionFactory getInstance(){ if( instance == null ){ instance = new ConnectionFactory(); } return instance; } private ConnectionFactory(){ // private constructor implementation } } Because I'm not quite sure about the behavior of a static synchronized method, I get some suggestion from google -- do not have (or as less as possible) multiple static synchronized methods in the same class. I guess when implementing static synchronized method, a lock belongs to Class object is used so that multiple static synchronized methods may degrade performance of the system. Am I right? or JVM use other mechanism to implement static synchronized method? What's the best practice if I have to implement multiple static synchronized methods in a class? Thank you all! Kind regards!

  Read the article

• How to search for duplicate values in a huge text file having around Half Million records

  - by Shibu

  I have an input txt file which has data in the form of records (each row is a record and represents more or less like a DB table) and I need to find for duplicate values. For example: Rec1: ACCOUNT_NBR_1*NAME_1*VALUE_1 Rec2: ACCOUNT_NBR_2*NAME_2*VALUE_2 Rec3: ACCOUNT_NBR_1*NAME_3*VALUE_3 In the above set, the Rec1 and Rec2 are considered to be duplicates as the ACCOUNT NUMBERS are same(ACCOUNT_NBR1). Note: The input file shown above is a delimiter type file (the delimiter being *) however the file type can also be a fixed length file where each column starts and ends with a specified positions. I am currently doing this with the following logic: Loop thru each ACCOUNT NUMBER Loop thru each line of the txt file and record and check if this is repeated. If repeated record the same in a hashtable. End End And I am using 'Pattern' & 'BufferedReader' java API's to perform the above task. But since it is taking a long time, I would like to know a better way of handling it. Thanks, Shibu

  Read the article

• C#: Creating an editable object inside a PictureBox

  - by ET

  My goal is to let the user click on a specific location on a map to add a Placemark, and then edit the placemark by click its icon (change its name, move it around, etc). I am using a PictureBox to show the map, and by registering the MouseDoubleClick event I am drawing an Image on the map with GDI+ DrawImage() method. The problem is that after the placemark's Image was drawn, it does not editable: the user cant click the icon and move it around, change its name etc. Is there any other design pattern I can follow? maybe using other controls... ?

  Read the article

• In c++ is there any Events/delegates/interfaces/notifications! anything?

  - by Bach

  Say i have these classes ViewA and ViewB In objective C using the delegate pattern I could do @protocol ViewBDelegate{ - (void) doSomething(); } then in ViewB interface: id<ViewBDelegate> delegate; then in ViewA implementation i set the delegate: viewB.delegate = self; and now I can call in doSomething from viewB onto any that unknown type delegate. [delegate doSomething]; "C++ How to Program" has been the worse read an can't find simple examples that demonstrates basic design patterns. What i'm looking for in C++ is: events ActionScript and java either delegates or notifications in Objective C anything that allows class A, Class B and Class C to know that ClassX didSomething()!!! thanks

  Read the article

• What difference does it make to use several script blocks on a web page?

  - by Jan Aagaard

  What difference does it make to use more than one script block on a web page? I have pasted in the standard code for including Google Analytics as an example, and I have seen the same pattern used in other places. Why is this code separated into two separate script blocks instead of just using a single one? <script type="text/javascript"> var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); </script> <script type="text/javascript"> try{ var pageTracker = _gat._getTracker("UA-xxxxxx-x"); pageTracker._trackPageview(); } catch(err) {} </script>

  Read the article

• Should I always release self for failed init methods?

  - by leo

  Should I always release self when there is a failure inside init, or should I only do so if I have initialized instance variables first? To put it another way, is this pattern valid? Is there a time when I shouldn't release self inside an init method, or should I assume that if the control flow enters init, self has at least a retain count of 1? - (id)init { if ((self = [super init]) == nil) { [self release]; return nil; } //do some init stuff if (somethingFailed) { [self release]; return nil; } return self; }

  Read the article

• Django - Static content display based on URL

  - by Steven Potter

  I'm working on a Django site with a basic three column design. Left column navigation, center column content and right column URL specific content blocks. My question is about the best method of controlling the URL specific content blocks in the right column. I am thinking of something along the lines of the Flatpages app that will make the content available to the template context if the URL matches a pre-determined pattern (perhaps regex?). Does anyone know if such an app already exists? If not, I am looking for some advice about the best way to implement it. Particularly in relation to the matching of patterns to the current URL. Is there any good way to re-use parts of the Django URL dispatcher for this use?

  Read the article

• Avoiding Nested Blocks

  - by Helium3

  If there is a view controller that wants to execute a number of block based tasks one at a time, how can the control be given back to the view controller after a completion block has executed. Lets say ViewControllerOne wants to execute a number of tasks, each relying on the result of the previous one, how would this control be given back to the viewcontroller after each completion block has been executed? I started thinking about this and I was heading towards a deeply nested block pattern that will surely only cause confusion to whoever else reads or tests it. A task executes and the completion block returns the result or error which is needed by the next task, which has its own completion task, that the next task relies on and so forth. How can the control be managed in one place, the viewcontroller? Would the completion block just call the next function that handles the next task, using a pointer to the view controller?

  Read the article

• How to imitate the workflow view of Automator?

  - by andyfeind

  I’m starting to develop my first full-blown Cocoa application containing a view which I would like to behave (and look) similar to Automator’s AMWorkflowView. The basic features I’d like to achieve: Positioning of subviews Display of subviews in expanded / collapsed states Multiple selection Drag and drop In order to get accustomed to Cocoa, I started with a custom NSView which mainly served as a container for the custom subviews and handled their positioning and multiple selection. The subviews are also subclasses of NSView, and contain a variable amount of views themselves, like buttons, labels and popup menus, and therefore can have different heights. This worked quite well, but before going on, I want to make sure to have everything neat and tidy according to the MVC pattern. I suspect that there already is a class in Cocoa that facilitates the implementation of a view container, like maybe NSCollectionView. It seems that there is no (easy) way to display differently sized views in an NSCollectionView, though. Should I continue implementing my custom NSView (probably using an NSArrayController for selection and sorting support), or are there better ways to go? Any help is much appreciated

  Read the article

• Simplest LINQ in C# troubleshooting.

  - by Jay

  I'm trying to learn a bit of LINQ but I'm having compile issues right off the bat. Is there any specific reason why this won't work? using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace HelloLINQ { class HelloLINQ { public static void Main() { Example1(); } public static void Example1() { var numbers = new int[] { 1, 5, 3, 7, 3, 8, 9, 3, 6, 6, 2 }; var under5 = from n in numbers select n; foreach (var n in under5) { Console.WriteLine(n); } } } } The error is: Could not find an implementation of the query pattern for source type 'int[]'. 'Select' not found. Are you missing a reference to 'System.Core.dll' or a using directive for 'System.Linq'?

  Read the article

• iPhone UIImage number recognition

  - by Skeep

  Hi All, I have a small UIImage (jpg) with a single typed number. I want to be able to read the number with some kind of pattern recognition. I'm really not sure where to start, so any help would be appreciated. my initial idea was to compare this image with other images. For instance compare the image with that of a 1,2,3, etc until a match was found. That just seems slow and cumbersome and wondered if there was a better way to do it? Thanks

  Read the article

• Break a string into parts, returning all characters

  - by Benjamin

  I want to break a string according to the following rules: all consecutive alpha-numeric chars, plus the dot (.) must be treated as one part all other consecutive chars must be treated as one part consecutive combinations of 1 and 2 must be treated as different parts no whitespace must be returned For example this string: Method(hierarchy.of.properties) = ? Should return this array: Array ( [0] => Method [1] => ( [2] => hierarchy.of.properties [3] => ) [4] => = [5] => ? ) I was unsuccessful with preg_split(), as AFAIK it cannot treat the pattern as an element to be returned. Any idea for a simple way to do this?

  Read the article

• Help with regex pulling XML data from response body in PHP

  - by spdaly

  I am working on a project that pulls data from JMS queue using PHP and Zend Framework. The HTTP client response is below. All I need is the XML string. I came up with /(.*)<\/RequestDetails/gs which tests ok on http://gskinner.com/RegExr/ but the preg_match call is returning an empty matches array. I'm going to continue to hunt around for a pattern, but thought I would post here as well. Thanks to all who read, etc... Steve UPDATE: I can't get the code to paste correctly. Here's a link to a pastbin: http://pastebin.com/rQxzcfSg

  Read the article

• python processs complete list files matched

  - by thomytheyon

  Hi All, I'm trying to get a simple code working, unfortunatly im a python beginner. My script should return a list of files that doesn't match a pattern, more information here : http://stackoverflow.com/questions/2910106/python-grep-reverse-matching/2910288#2910288 My code is running but doesn't process the complete list of files found as it should : import sys,os filefilter = ['.xml','java','.jsp','lass'] path= "/home/patate/code/project" s = "helloworld" for path, subdirs, files in os.walk(path): for name in files: if name[-4:] in filefilter : f = str(os.path.join(path, name)) with open(f) as fp: if s in fp.read(): print "%s has the string" % f else: print "%s doesn't have the string" % f This code return : /home/patate/code/project/blabla/blabla/build.xml doesn't have the string None If i change f = str(os.path.join(path, name)) for print str(os.path.join(path, name)) I can see the whole list being printed. How can i process the whole list as i which to ? :( Thanks again.

  Read the article

• Scala match/compare enumerations

  - by williamstw

  I have an enumeration that I want to use in pattern matches in an actor. I'm not getting what i'd expect and, now, I'm suspecting I'm missing something simple. My enumeration, object Ops extends Enumeration { val Create = Value("create") val Delete = Value("delete") } Then, I create an Ops from a String: val op = Ops.valueOf("create") Inside my match, I have: case (Ops.Create, ...) But Ops.Create doesn't seem to equal ops.valueOf("create") The former is just an atom 'create' and the later is Some(create) Hopefully, this is enough info for someone to tell me what I'm missing... Thanks

  Read the article

• Which would be better? Storing/access data in a local text file, or in a database?

  - by TerranRich

  Basically, I'm still working on a puzzle-related website (micro-site really), and I'm making a tool that lets you input a word pattern (e.g. "r??n") and get all the matching words (in this case: rain, rein, ruin, etc.). Should I store the words in local text files (such as words5.txt, which would have a return-delimited list of 5-letter words), or in a database (such as the table Words5, which would again store 5-letter words)? I'm looking at the problem in terms of data retrieval speeds and CPU server load. I could definitely try it both ways and record the times taken for several runs with both methods, but I'd rather hear it from people who might have had experience with this. Which method is generally better overall?

  Read the article

• How to organize architecture WPF project?

  - by Dmitriy

  Hello! In my WPF project i want to have only one Window - MainWindow and UserControls as working part. I have some little different applications in one, and want to make navigation on top of my MainWindow as buttons. And little applications as UserControl. In MainWindow - grid with Big Empty Zone - which use to keep and run work. But, i want to navigate to other userControl from another. (probably do not understand :() How organize architecture WPF project that: one main window and many usercontrols which places in mainwindow and replace each other in turn. and there is the possibility of navigating from another usercontrol to another. May be it's MVVM, but i don't understand how this pattern can help me.

  Read the article

• Buffering db inserts in multithreaded program

  - by Winter

  I have a system which breaks a large taks into small tasks using about 30 threads as a time. As each individual thread finishes it persists its calculated results to the database. What I want to achieve is to have each thread pass its results to a new persisance class that will perform a type of double buffering and data persistance while running in its own thread. For example, after 100 threads have moved their data to the buffer the persistance class then the persistance class swaps the buffers and persists all 100 entries to the database. This would allow utilization of prepared statements and thus cut way down on the I/O between the program and the database. Is there a pattern or good example of this type of multithreading double buffering?

  Read the article

• Is it inefficient to access a python class member container in a loop statement?

  - by Dave

  Hi there. I'm trying to adopt some best practices to keep my python code efficient. I've heard that accessing a member variable inside of a loop can incur a dictionary lookup for every iteration of the loop, so I cache these in local variables to use inside the loop. My question is about the loop statement itself... if I have the following class: class A(object): def init(self) self.myList = [ 'a','b','c', 'd', 'e' ] Does the following code in a member function incur one, or one-per-loop-iteration (5) dictionary lookups? for letter in self.myList: print letter IE, should I adopt the following pattern, if I am concerned about efficiency... localList = self.myList for letter in localList: print letter or is that actually LESS efficient due to the local variable assign? Note, I am aware that early optimization is a dangerous pitfall if I'm concerned about the overall efficiency of code development. Here I am specifically asking about the efficiency of the code, not the coding. Thanks in advance! D

  Read the article

• What are the common patterns in web programming?

  - by lankerisms

  I have been trying to write my first big web app (more than one cgi file) and as I kept moving forward with the rough prototype, paralelly trying to predict more tasks, this is the todo that got accumulated (In no particular order). * Validations and input sanitizations * Object versioning (to avoid edit conflicts. I dont want hard locks) * Exception handling * memcache * xss and injection protections * javascript * html * ACLs * phonetics in search, match and find duplicates (for form validation) * Ajaxify!!! (I have snipped off the project specific items.) I know that each todo will be quite tied up to its project and technologies used. What I am wondering though, is if there is a pattern in your todo items as well as the sequence in which you experienced guys have come across them.

  Read the article

• What books help one to learn to read code?

  - by Daniel

  Lion's Commentary on Unix Sixth Edition with Source Code is a wonderful book to learn how to read code. Reading code is important -- how does one learn how to write excellent code without having read excellent code? But, sadly, while great writers, of fiction and non-fiction, all spend a great deal of time reading stuff, we, programmers, seem to avoid it like the plague. Worse still, programming books usually go the same way. They might show a pattern or a style, but they often avoid showing good, complex code, and helping one go through it. There are exceptions, of course. I hope. So, with that in mind, what books are to be found which help one learn how to read code?

  Read the article

• Custom changeable handler when a Service finishes downloading a file

  - by jax

  I have a Service that downloads a file from the internet. What I want is for the response (an InputStream in this case) to be handled by a custom handler that can be switched (like a strategy pattern) but I can't figure out how to do this. So basically the User of the API would be able to plug in different handlers for the response, some would parse XML, others might save files etc. I realise I could pass through the activity context and execute the method from this (given some interface) but I don't want to do this obviously, in case the Activity is closed in the meantime while the file is still downloaded. How might I do this?

  Read the article

• Strategy for desugaring Haskell

  - by luqui

  I'm developing a virtual machine for purely functional programs, and I would like to be able to test and use the the wide variety of Haskell modules already available. The VM takes as input essentially terms in the untyped lambda calculus. I'm wondering what would be a good way to extract such a representation from modern Haskell modules (eg. with MPTC's, pattern guards, etc.). I did a little research and there doesn't seem to be a tool that does this already (I would be delighted to be mistaken), and that's okay. I'm looking for an approach. GHC Core seems too operationally focused, especially since one of the things the VM does is to change the evaluation order significantly. Are there any accessible intermediate representations that correspond more closely to the lambda calculus?

  Read the article

< Previous Page | 166 167 168 169 170 171 172 173 174 175 176 177  | Next Page >