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  • How to elegantly work with a lot of print functions?

    - by user1824372
    I'm working on a Python project that is executed on a terminal (or console) for which I am planning to implement a GUI. I did not major in CS so I really have no idea how to effectively design a terminal GUI such that: the user interface looks good in GUI, it is directed to a certain widget, let's say, a text label, or a bottom bar, or a hide-able frame. Do you have any suggestions? Currently, I am using the print function to provide essential information on STDOUT during execution, so a lot of print calls are distributed here and there in the code. I'm thinking of using macro-like variables such as 'FILE_NOT_EXISTS_MESSAGE' for printing, and all of them and their values would be defined in one file. Is that a standard way to do this? Should I introduce a logging system? In summary, I'm looking for a pattern for handling console output that is effective and adaptable.

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  • Testing complex compositions

    - by phlipsy
    I have a rather large collection of classes which check and mutate a given data structure. They can be composed via the composition pattern into arbitrarily complex tree-like structures. The final product contains a lot of these composed structures. My question is now: How can I test those? Albeit it is easy to test every single unit of these compositions, it is rather expensive to test the whole compositions in the following sense: Testing the correct layout of the composition-tree results in a huge number of test cases Changes in the compositions result in a very laborious review of every single test case What is the general guideline here?

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  • How to create a manager class without global variables nor singletons?

    - by Omega
    I would like to implement some kind of manager class in my application. It will be in charge of loading textures, processing them, distributing them etc... At first, I wanted to make a global variable that simply contains an instance of my manager class. I found this question: http://stackoverflow.com/questions/4646577/global-variables-in-java. However, the users there seem to recommend to never use global variables. Fine then, I once heard about Singletons, so I though I could use that instead. I mean, creating just one instance of my manager class sounds good. However, I found this other question: When is Singleton appropriate?, which basically tells me that Singletons are, in most scenarios, some kind of anti-pattern. Now I am a bit lost - what other approach can I take to create my manager class, whose only requirement is to be accessible from anywhere?

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  • PHP regex to search across multiple lines

    - by Gaz
    I'm using preg_* in PHP to search for the pattern <!-- %{data=THIS GETS MATCHED}% --> and pull out the matched text. The pattern for this is: preg_match('#<!-- %{' . $knownString . '\s*=\s*(.*?)}% -->#', ...) What I would like it to do is search across multiple lines for the string. For example: <!-- %{data= THIS GETS MATCHED AND RETURNED }% --> How can I edit my current pattern to have this search ability?

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  • Tips to Make Your Website Cell Phone Friendly

    - by Aditi
    Working on a new website design? or Redesigning your website? There is a lot more to consider now a days not just user experience, clean code, CSS etc. one of the important attribute one must not miss, which is making them mobile friendly! With the growing use of handhelds & unlimited data plans, people browse on their cellphones! and All come in different sizes! it is tough to make a website that would look great not just on a high resolution widescreen monitor/LCD, but also should look equally impressive on the low resolutions of cellphones. We are today going to discuss about such factors that can help you make a website Cellphone Friendly. Fluid Width Layouts As we start discussing about this, Most people speak of the Fluid Width Layouts as vital step in moving your website to be mobile friendly. Fluid width allows the width of your website stretch or shrink depending on the browser size. However, having a layout which flows with the width of the screen’s resolution is certainly convenient, more often than not the website was originally laid out for a desktop in mind. Compressing a fluid layout to 320 pixels can do some serious damage to layout, Thus some people strongly believe it is far better to have a mobile style sheet and lay out the content specifically for that screen and have more control on the display. The best thing to do is to detect the type of platform that is connected to your website and disabling or changing some tools and effects to make it look better if not perfect. Keep Your Web Pages Short length One must avoid long pages on their website, a lot of scroll makes it very non user friendly for people, especially on mobile devices this is a huge draw back because of the longer load time it takes to download the webpage. Everyone likes crisp & concise content such pages are easier to load & browse. This makes your website accessible across all platforms. Also try to keep shorter urls, if they have to type..save them from that much work especially if someone is using a cellphone with no QWERTY keyboard it can be tough. Usable Navigation & Search Unlike Desktops, your website’s Navigation won’t super work on a cellphone. Keep in mind the user experience for cellphone users as you design your Navigation. Try to keep your content centered as they do have difficulty in reading the webpage. I always look upto Google and their pages as available on mobile as a great example. Keeping a functional & very visible search bar helps mobile users navigate by searching. Understanding Clean Website Code : Evolved for Mobile Clean code is important when you consider the diversity out there for handheld devices. Some cell phones may only understand WAP. More capable phones may understand WAP2, which allows rendering websites with XHTML and CSS. Most mobiles won’t display tables, floats, frames, JavaScript, and dynamic menus. Most cellphone will not support cookies. Devices at the high end of the mobile market such as BlackBerry, Palm, or the upcoming iPhone are highly capable and support nearly as much as a standard computer..but masses still do not have such phones. You can use specific emulators to test your website on mobile devices. Make sure your color combinations provide good contrast between foreground and background colors, particularly for devices with fewer color options.

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  • Project structure: where to put business logic

    - by Mister Smith
    First of all, I'm not asking where does business logic belong. This has been asked before and most answers I've read agree in that it belongs in the model: Where to put business logic in MVC design? How much business logic should be allowed to exist in the controller layer? How accurate is "Business logic should be in a service, not in a model"? Why put the business logic in the model? What happens when I have multiple types of storage? However people disagree in the way this logic should be distributed across classes. There seem to exist three major currents of thought: Fat model with business logic inside entity classes. Anemic model and business logic in "Service" classes. It depends. I find all of them problematic. The first option is what most Fowlerites stick to. The problem with a fat model is that sometimes a business logic funtion is not only related to a class, and instead uses a bunch of other classes. If, for example, we are developing a web store, there should be a function that calcs an order's total. We could think of putting this function inside the Order class, but what actually happens is that the logic needs to use different classes, not only data contained in the Order class, but also in the User class, the Session class, and maybe the Tax class, Country class, or Giftcard, Payment, etc. Some of these classes could be composed inside the Order class, but some others not. Sorry if the example is not very good, but I hope you understand what I mean. Putting such a function inside the Order class would break the single responsibility principle, adding unnecesary dependences. The business logic would be scattered across entity classes, making it hard to find. The second option is the one I usually follow, but after many projects I'm still in doubt about how to name the class or classes holding the business logic. In my company we usually develop apps with offline capabilities. The user is able to perform entire transactions offline, so all validation and business rules should be implemented in the client, and then there's usually a background thread that syncs with the server. So we usually have the following classes/packages in every project: Data model (DTOs) Data Access Layer (Persistence) Web Services layer (Usually one class per WS, and one method per WS method). Now for the business logic, what is the standard approach? A single class holding all the logic? Multiple classes? (if so, what criteria is used to distribute the logic across them?). And how should we name them? FooManager? FooService? (I know the last one is common, but in our case it is bad naming because the WS layer usually has classes named FooWebService). The third option is probably the right one, but it is also devoid of any useful info. To sum up: I don't like the first approach, but I accept that I might have been unable to fully understand the Zen of it. So if you advocate for fat models as the only and universal solution you are welcome to post links explaining how to do it the right way. I'd like to know what is the standard design and naming conventions for the second approach in OO languages. Class names and package structure, in particular. It would also be helpful too if you could include links to Open Source projects showing how it is done. Thanks in advance.

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  • Algorithm design, "randomising" timetable schedule in Python although open to other languages.

    - by S1syphus
    Before I start I should add I am a musician and not a native programmer, this was undertook to make my life easier. Here is the situation, at work I'm given a new csv file each which contains a list of sound files, their length, and the minimum total amount of time they must be played. I create a playlist of exactly 60 minutes, from this excel file. Each sample played the by the minimum number of instances, but spread out from each other; so there will never be a period where for where one sound is played twice in a row or in close proximity to itself. Secondly, if the minimum instances of each song has been used, and there is still time with in the 60 min, it needs to fill the remaining time using sounds till 60 minutes is reached, while adhering to above. The smallest duration possible is 15 seconds, and then multiples of 15 seconds. Here is what I came up with in python and the problems I'm having with it, and as one user said its buggy due to the random library used in it. So I'm guessing a total rethink is on the table, here is where I need your help. Whats is the best way to solve the issue, I have had a brief look at things like knapsack and bin packing algorithms, while both are relevant neither are appropriate and maybe a bit beyond me.

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  • Using Nearest Neighbour Algorithm for image pattern recognition

    - by user293895
    So I want to be able to recognise patterns in images (such as a number 4), I have been reading about different algorithms and I would really like to use the Nearest Neighbour algorithm, it looks simple and I do understand it based on this tutorial: http://people.revoledu.com/kardi/tutorial/KNN/KNN_Numerical-example.html Problem is, although I understand how to use it to fill in missing data sets, I don't understand how I could use it as a pattern recognition tool to aim in Image Shape Recognition. Could someone please shed some light as to how this algorithm could work for pattern recognition? I have seen tutorials using OpenCV, however I don't really want to use this library as I have the ability to do the pre-processing myself, and it seems silly that I would implement this library just for what should be a simple nearest neighbour algorithm.

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  • JavaScript/Dojo Module Pattern - how to debug?

    - by djna
    I'm working with Dojo and using the "Module Pattern" as described in Mastering Dojo. So far as I can see this pattern is a general, and widely used, JavaScript pattern. My question is: How do we debug our modules? So far I've not been able to persuade Firebug to show me the source of my module. Firebug seems to show only the dojo eval statement used to execute the factory method. Hence I'm not able to step through my module source. I've tried putting "debugger" statements in my module code, and Firebug seems to halt correctly, but does not show the source. Contrived example code below. This is just an example of sufficient complexity to make the need for debugging plausible, it's not intended to be useful code. The page <!-- Experiments with Debugging --> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <title>console me</title> <style type="text/css"> @import "../dojoroot/dojo/resources/dojo.css"; @import "../dojoroot/dijit/themes/tundra/tundra.css"; @import "edf.css"; </style> <script type="text/javascript" src="../dojoroot/dojo/dojo.js"> </script> <script type="text/javascript" > dojo.registerModulePath("mytest", "../../mytest"); dojo.require("mytest.example"); dojo.addOnLoad(function(){ mytest.example.greet(); }); </script> </head> <body class="tundra"> <div id="bulletin"> <p>Just Testing</p> </div> </body> </html> <!-- END: snip1 --> The java script I'd like to debug dojo.provide("mytest.example"); dojo.require("dijit.layout.ContentPane"); /** * define module */ (function(){ //define the main program functions... var example= mytest.example; example.greet= function(args) { var bulletin = dojo.byId("bulletin"); console.log("bulletin:" + bulletin); if ( bulletin) { var content = new dijit.layout.ContentPane({ id: "dummy", region: "center" }); content.setContent('Greetings!'); dojo._destroyElement(bulletin); dojo.place(content.domNode, dojo.body(), "first"); console.log("greeting done"); } else { console.error("no bulletin board"); } } })();

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  • How do you model roles / relationships with Domain Driven Design in mind?

    - by kitsune
    If I have three entities, Project, ProjectRole and Person, where a Person can be a member of different Projects and be in different Project Roles (such as "Project Lead", or "Project Member") - how would you model such a relationship? In the database, I currently have the following tablers: Project, Person, ProjectRole Project_Person with PersonId & ProjectId as PK and a ProjectRoleId as a FK Relationship. I'm really at a loss here since all domain models I come up with seem to break some "DDD" rule. Are there any 'standards' for this problem? I had a look at a Streamlined Object Modeling and there is an example what a Project and ProjectMember would look like, but AddProjectMember() in Project would call ProjectMember.AddProject(). So Project has a List of ProjectMembers, and each ProjectMember in return has a reference to the Project. Looks a bit convoluted to me. update After reading more about this subject, I will try the following: There are distinct roles, or better, model relationships, that are of a certain role type within my domain. For instance, ProjectMember is a distinct role that tells us something about the relationship a Person plays within a Project. It contains a ProjectMembershipType that tells us more about the Role it will play. I do know for certain that persons will have to play roles inside a project, so I will model that relationship. ProjectMembershipTypes can be created and modified. These can be "Project Leader", "Developer", "External Adviser", or something different. A person can have many roles inside a project, and these roles can start and end at a certain date. Such relationships are modeled by the class ProjectMember. public class ProjectMember : IRole { public virtual int ProjectMemberId { get; set; } public virtual ProjectMembershipType ProjectMembershipType { get; set; } public virtual Person Person { get; set; } public virtual Project Project { get; set; } public virtual DateTime From { get; set; } public virtual DateTime Thru { get; set; } // etc... } ProjectMembershipType: ie. "Project Manager", "Developer", "Adviser" public class ProjectMembershipType : IRoleType { public virtual int ProjectMembershipTypeId { get; set; } public virtual string Name { get; set; } public virtual string Description { get; set; } // etc... }

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  • How to design a command line program and keep it open for a future GUI?

    - by systempuntoout
    What are some best practices to keep in mind when developing a script program that could be integrated with a GUI, probably by somebody else, in the future? Example scenario: i develop a fancy python CLI program that scrapes every unicorn images from the web i decide to publish it on github a unicorn fan programmer decide to take the sources and build a GUI on them. he gives up because my code is a mess How do i avoid step 4 and let unicorn fan programmer build his GUI without hassle?

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  • Is it a good object-oriented-design practice to send a pointer to private data to another class?

    - by Denis
    Hello everyone, There is well known recommendation not to include into class interface method that returns a pointer (or a reference) to private data of the class. But what do you think about public method of a class that sends to another class a pointer to the private data of the first one. For example: class A { public: void fA(void) {_b.fB(&_var)}; private: B _b; int _var; }; I think that it is some sort of data hiding damage: the private data define state of their own class, so why should one class delegate changes of its own state to another one? What do you think? Denis

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  • Is Microformat's date-value-pattern fully accessible?

    - by Stephen
    Has there been an announcement (outside microformats.org) that the value-class-pattern is fully accessible? e.g. given <abbr class="value" title="2008-06-24">this Tuesday</abbr>, will a screen reader say "24 June 2008" or will it say "2008 dash 6 dash 24"? History Microformats came along, and were great, except that dates etc were stored in abbr tags: <abbr class="dtstart" title="20070312T1700-06"> March 12, 2007 at 5 PM, Central Standard Time </abbr>` This lead to screen readers doing ridiculous things as noted in hAccessibility. Now that microformats.org have released the value-class-pattern it's a lot better. But I'm left unable to find a declaration from WaSP (or another accessibility source not directly tied to microformats) that declaratively states that they are now accessible to screen readers etc.

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  • Java Inter Application Form Communication Observer Pattern

    - by ikurtz
    Observer pattern? Where do i get examples of this in Java (i know google but was hoping for some personal insight also.) On to a proper explanation of my issue: i have 3 forms/windows. "board" is the main form that loads as the application. "chat" is where the text chat takes place. "network" is where network connection is established. i have the game (connect4) working locally and i would like to implement a networked version of it also. my idea is maybe it is related to Observer pattern to have a thread (or something) monitoring network state during runtime and update the chat and board forms of the current network status as well as delivering received data from the network. are my ideas valid? or how should i go about establishing network and network status updates throughout the application? thank you for your input.

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  • Singleton pattern and broken double checked locking in real world java application

    - by saugata
    I was reading the article Double-checked locking and the Singleton pattern, on how double checked locking is broken, and some related questions here on stackoverflow. I have used this pattern/idiom several times without any issues. Since I have been using Java 5, my first thought was that this has been rectified in Java 5 memory model. However the article says This article refers to the Java Memory Model before it was revised for Java 5.0; statements about memory ordering may no longer be correct. However, the double-checked locking idiom is still broken under the new memory model. I'm wondering if anyone has actually run into this problem in any application and under what conditions.

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  • EF and design pattern

    - by kathy
    Hello, I’m working on a high volume transactional enterprise application(asp.net, windows app, oracle app as client) which has been designed using n-tire application and SOA architecture .The application was developed in the .NET platform utilizing C#,VB.NET, Framework 3.5 (I’m planning to upgrade to the , Framework 4.0), EF( EF in the data layer level) and WCF(WCF services in the service layer level) Since this is the first project using EF, and having read about using EF in n-tier and SOA applications, and the features available in the EF Feature, I have the following points: Which design pattern should I use in EF( Simple Entities, Change Set, Self-Tracking Entities and DTOs) in the data layer level In addition Which design pattern should I use in the other tier and layer to get the best practices of EF Thanks

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  • split a string based on pattern in java - capital letters and numbers

    - by rookie
    Hi all I have the following string "3/4Ton". I want to split it as -- word[1] = 3/4 and word[2] = Ton. Right now my piece of code looks like this:- Pattern p = Pattern.compile("[A-Z]{1}[a-z]+"); Matcher m = p.matcher(line); while(m.find()){ System.out.println("The word --> "+m.group()); } It carries out the needed task of splitting the string based on capital letters like:- String = MachineryInput word[1] = Machinery , word[2] = Input The only problem is it does not preserve, numbers or abbreviations or sequences of capital letters which are not meant to be separate words. Could some one help me out with my regular expression coding problem. Thanks in advance...

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  • Which are the most important media queries to use in creating mobile responsive design?

    - by Matt
    There are a lot different media queries for mobile screen sizes. It can be overwhelming to accomodate all of them when designing a responsive mobile site. Which are the most important ones to use when designing for mobile? I found this article that does a pretty good job of outlining the available media queries: http://css-tricks.com/snippets/css/media-queries-for-standard-devices/. /* Smartphones (portrait and landscape) ----------- */ @media only screen and (min-device-width : 320px) and (max-device-width : 480px) { /* Styles */ } /* Smartphones (landscape) ----------- */ @media only screen and (min-width : 321px) { /* Styles */ } /* Smartphones (portrait) ----------- */ @media only screen and (max-width : 320px) { /* Styles */ } /* iPads (portrait and landscape) ----------- */ @media only screen and (min-device-width : 768px) and (max-device-width : 1024px) { /* Styles */ } /* iPads (landscape) ----------- */ @media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : landscape) { /* Styles */ } /* iPads (portrait) ----------- */ @media only screen and (min-device-width : 768px) and (max-device-width : 1024px) and (orientation : portrait) { /* Styles */ } /* Desktops and laptops ----------- */ @media only screen and (min-width : 1224px) { /* Styles */ } /* Large screens ----------- */ @media only screen and (min-width : 1824px) { /* Styles */ } /* iPhone 4 ----------- */ @media only screen and (-webkit-min-device-pixel-ratio : 1.5), only screen and (min-device-pixel-ratio : 1.5) { /* Styles */ }

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  • Design suggestions for creating document management structure using hidden shares.

    - by focus.nz
    I need to add some document management functionality into my software. Documents will be grouped by company name and project name. The folders need to be accessed by the application using the id numbers of clients/projects, but also easily browsed by the end user using windows explorer. Clients and Projects will be stored in a database. I am thinking of having the software create the folders using the friendly name and then using a hidden share with the id number for the software to access the files. The folder structure would be something like this --Company 1 (Company-1234$) -- Project 101 (Project-101$) -- Project 102 (Project-102$) -- Project 103 (Project-103$) -- Company 2 (Company-5678$) -- Project 201 (Project-201$) -- Project 202 (Project-202$) -- Project 203 (Project-203$) So in the example above there would be a company called "Company 1" with a ID of "1234". When browsing the folders using windows explorer the user would see \\ServerName\Documents\Company1 and you could also access the same folder from \\ServerName\Documents\Company-1234$ By using the hidden share, if the company name changes or its renamed for some reason it doesn't break the link in the application because its using the hidden shared based on the ID that never changes. Will having hundreds (maybe thousands) or hidden shares on a server provide a huge performance hit? Does any one have any suggestions or alternatives to provide this feature?

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  • Looking for design/architecture suggestions for a simple HTML game.

    - by z-boss
    Imagine that HTML page is a game surface (see picture). User can have n number of boards (blue divs) on his page. Each board can be moved, re-sized, relabeled, created new and removed. Inside each board there are m number of figures (purple divs). Each of these user can move inside the board or to another board, re-size, change color and label, delete, add new. The goal of the game is not important, but let's say it is to rearrange figures in a certain way so that they disappear. But the goal of the programmer is to save the whole game surface in the database for every user of the site, and to load it later when he returns. So, how do I go about data exchange between client and the database? I'll give my idea in one of the answers.

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