Search Results

Search found 56529 results on 2262 pages for 'html object'.

Page 156/2262 | < Previous Page | 152 153 154 155 156 157 158 159 160 161 162 163  | Next Page >

• Hadoop and Object Reuse, Why?

  - by Andrew White

  In Hadoop, objects passed to reducers are reused. This is extremely surprising and hard to track down if you're not expecting it. Furthermore, the original tracker for this "feature" doesn't offer any evidence that this change actually improved performance (unless I missed it). It would speed up the system substantially if we reused the keys and values [...] but I think it is worth doing. This seems completely counter to this very popular answer. Is there some credence to the Hadoop developer's claim? Is there something "special" about Hadoop that would invalidate the notion of object creation being cheap?

  Read the article

• Why is my class worse than the hierarchy of classes in the book (beginner OOP)?

  - by aditya menon

  I am reading this book. The author is trying to model a lesson in a college. The goal is to output the Lesson Type (Lecture or Seminar), and the Charges for the lesson depending on whether it is a hourly or fixed price lesson. So the output should be: lesson charge 20. Charge type: hourly rate. lesson type seminar. lesson charge 30. Charge type: fixed rate. lesson type lecture. When the input is as follows: $lessons[] = new Lesson('hourly rate', 4, 'seminar'); $lessons[] = new Lesson('fixed rate', null, 'lecture'); I wrote this: class Lesson { private $chargeType; private $duration; private $lessonType; public function __construct($chargeType, $duration, $lessonType) { $this->chargeType = $chargeType; $this->duration = $duration; $this->lessonType = $lessonType; } public function getChargeType() { return $this->getChargeType; } public function getLessonType() { return $this->getLessonType; } public function cost() { if($this->chargeType == 'fixed rate') { return "30"; } else { return $this->duration * 5; } } } $lessons[] = new Lesson('hourly rate', 4, 'seminar'); $lessons[] = new Lesson('fixed rate', null, 'lecture'); foreach($lessons as $lesson) { print "lesson charge {$lesson->cost()}."; print " Charge type: {$lesson->getChargeType()}."; print " lesson type {$lesson->getLessonType()}."; print "<br />"; } But according to the book, I am wrong (I am pretty sure I am, too). The author gave a large hierarchy of classes as the solution instead. In a previous chapter, the author stated the following 'four signposts' as the time when I should consider changing my class structure: Code Duplication The Class Who Knew Too Much About His Context The Jack of All Trades - Classes that try to do many things Conditional Statements The only problem I can see is Conditional Statements, and that too in a vague manner - so why refactor this? What problems do you think might arise in the future that I have not foreseen?

  Read the article

• Basis of definitions

  - by Yttrill

  Let us suppose we have a set of functions which characterise something: in the OO world methods characterising a type. In mathematics these are propositions and we have two kinds: axioms and lemmas. Axioms are assumptions, lemmas are easily derived from them. In C++ axioms are pure virtual functions. Here's the problem: there's more than one way to axiomatise a system. Given a set of propositions or methods, a subset of the propositions which is necessary and sufficient to derive all the others is called a basis. So too, for methods or functions, we have a desired set which must be defined, and typically every one has one or more definitions in terms of the others, and we require the programmer to provide instance definitions which are sufficient to allow all the others to be defined, and, if there is an overspecification, then it is consistent. Let me give an example (in Felix, Haskell code would be similar): class Eq[t] { virtual fun ==(x:t,y:t):bool => eq(x,y); virtual fun eq(x:t, y:t)=> x == y; virtual fun != (x:t,y:t):bool => not (x == y); axiom reflex(x:t): x == x; axiom sym(x:t, y:t): (x == y) == (y == x); axiom trans(x:t, y:t, z:t): implies(x == y and y == z, x == z); } Here it is clear: the programmer must define either == or eq or both. If both are defined, the definitions must be equivalent. Failing to define one doesn't cause a compiler error, it causes an infinite loop at run time. Defining both inequivalently doesn't cause an error either, it is just inconsistent. Note the axioms specified constrain the semantics of any definition. Given a definition of == either directly or via a definition of eq, then != is defined automatically, although the programmer might replace the default with something more efficient, clearly such an overspecification has to be consistent. Please note, == could also be defined in terms of !=, but we didn't do that. A characterisation of a partial or total order is more complex. It is much more demanding since there is a combinatorial explosion of possible bases. There is an reason to desire overspecification: performance. There also another reason: choice and convenience. So here, there are several questions: one is how to check semantics are obeyed and I am not looking for an answer here (way too hard!). The other question is: How can we specify, and check, that an instance provides at least a basis? And a much harder question: how can we provide several default definitions which depend on the basis chosen?

  Read the article

• Are there any good reasons to intentionally serve a new web site in Quirks mode?

  - by wsanville

  I was a little surprised that Amazon's site doesn't specify a doctype, and is rendered in quirks mode. What could possibly be the reason for this? I understand what quirks mode is and why doctypes were introduced, but I can't understand why this would be intentionally left off. I guess it might simplify markup if they're trying to support ancient browsers, but isn't that like shooting yourself in the foot when it comes to modern browsers, especially when their site is so Javascript rich? Does this level the playing field when it comes to supporting really old browsers? Is there something else I'm missing?

  Read the article

• C# vector class - Interpolation design decision

  - by Benjamin

  Currently I'm working on a vector class in C# and now I'm coming to the point, where I've to figure out, how i want to implement the functions for interpolation between two vectors. At first I came up with implementing the functions directly into the vector class... public class Vector3D { public static Vector3D LinearInterpolate(Vector3D vector1, Vector3D vector2, double factor) { ... } public Vector3D LinearInterpolate(Vector3D other, double factor { ... } } (I always offer both: a static method with two vectors as parameters and one non-static, with only one vector as parameter) ...but then I got the idea to use extension methods (defined in a seperate class called "Interpolation" for example), since interpolation isn't really a thing only available for vectors. So this could be another solution: public class Vector3D { ... } public static class Interpolation { public static Vector3D LinearInterpolate(this Vector3D vector, Vector3D other, double factor) { ... } } So here an example how you'd use the different possibilities: { var vec1 = new Vector3D(5, 3, 1); var vec2 = new Vector3D(4, 2, 0); Vector3D vec3; vec3 = vec1.LinearInterpolate(vec2, 0.5); //1 vec3 = Vector3D.LinearInterpolate(vec1, vec2, 0.5); //2 //or with extension-methods vec3 = vec1.LinearInterpolate(vec2, 0.5); //3 (same as 1) vec3 = Interpolation.LinearInterpolation(vec1, vec2, 0.5); //4 } So I really don't know which design is better. Also I don't know if there's an ultimate rule for things like this or if it's just about what someone personally prefers. But I really would like to hear your opinions, what's better (and if possible why ).

  Read the article

• Nested Classes: A useful tool or an encapsulation violation?

  - by Bryan Harrington

  So I'm still on the fence as to whether or not I should be using these or not. I feel its an extreme violation of encapsulation, however I find that I am able to achieve some degree of encapsulation while gaining more flexibility in my code. Previous Java/Swing projects I had used nested classes to some degree, However now I have moved into other projects in C# and I am avoid their use. How do you feel about nested classes?

  Read the article

• Functional programming readability

  - by Jimmy Hoffa

  I'm curious about this because I recall before learning any functional languages, I thought them all horribly, awfully, terribly unreadable. Now that I know Haskell and f#, I find it takes a little longer to read less code, but that little code does far more than an equivalent amount would in an imperative language, so it feels like a net gain and I'm not extremely practiced in functional. Here's my question, I constantly hear from OOP folks that functional style is terribly unreadable. I'm curious if this is the case and I'm deluding myself, or if they took the time to learn a functional language, the whole style would no longer be more unreadable than OOP? Has anybody seen any evidence or got any anecdotes where they saw this go one way or another with frequency enough to possibly say? If writing functionally really is of lower readability than I don't want to keep using it, but I really don't know if that's the case or not..

  Read the article

• Code Smell: Inheritance Abuse

  - by dsimcha

  It's been generally accepted in the OO community that one should "favor composition over inheritance". On the other hand, inheritance does provide both polymorphism and a straightforward, terse way of delegating everything to a base class unless explicitly overridden and is therefore extremely convenient and useful. Delegation can often (though not always) be verbose and brittle. The most obvious and IMHO surest sign of inheritance abuse is violation of the Liskov Substitution Principle. What are some other signs that inheritance is The Wrong Tool for the Job even if it seems convenient?

  Read the article

• Make Offscreen Sliding Content Without Hurting SEO [duplicate]

  - by etangins

  This question already has an answer here: How bad is it to use display: none in CSS? 5 answers On my website I have content which is positioned off the screen, and then slides in when you click a button. For example, when you click the news button, content slides in with news. It didn't occur to me that this might be labeled as a black hat SEO technique, because I have content positioned off the screen with CSS that links elsewhere on my site, and a search engine could very easily interpret that as me hiding content for SEO purposes by positioning it off screen. Obviously, my intention was not to hide content, but was to make a sort of UI/UX content slider where content slides into view when a button is clicked. How can I make something to this effect (where content slides in and out), that would not comprise SEO?

  Read the article

• How does a search functionality fit in DDD with CQRS?

  - by Songo

  In Vaughn Vernon's book Implementing domain driven design and the accompanying sample application I found that he implemented a CQRS approach to the iddd_collaboration bounded context. He presents the following classes in the application service layer: CalendarApplicationService.java CalendarEntryApplicationService.java CalendarEntryQueryService.java CalendarQueryService.java I'm interested to know if an application will have a search page that feature numerous drop downs and check boxes with a smart text box to match different search patterns; How will you structure all that search logic? In a command service or a query service? Taking a look at the CalendarQueryService.java I can see that it has 2 methods for a huge query, but no logic at all to mix and match any search filters for example. I've heard that the application layer shouldn't have any business logic, so where will I construct my dynamic query? or maybe just clutter everything in the Query service?

  Read the article

• How prevent useless content load on the page in Responsive Design

  - by Ícaro Leandro

  In Responsive Design, we hide elements in the page with @media queries and display: hide in the CSS. Ok, But in my system: Browsers that have less than width: 800px, the layout must hide some content, not only hide, but avoid them load fully. I mean, in access with desktop with more than 800px of screen, the page load fully; In mobile devices, or even in desktop with less than 800px, not load some content. I want to make the page load faster in this browsers. The system are maked in PHP and have some Javascript. Thanks...

  Read the article

• TinyMCE autoresize plugin not works

  - by user31929

  I want to reproduce this simply behaviour : http://tinymcesupport.com/tutorials/autoresize-automatic-resize-plugin This is my init: <!-- TinyMCE --> <script type="text/javascript" src="js/jscripts/tiny_mce/tiny_mce.js"></script> <script type="text/javascript"> tinyMCE.init({ mode : "exact", elements : "pagina_testo_colonna1,pagina_testo_colonna2,pagina_testo_colonna3", theme : "advanced", plugins:"paste,autoresize", plugin_preview_width : "100%", width : "100%", theme_advanced_buttons1 : "pastetext,|,bold,italic,underline,strikethrough,|,bullist,numlist,|,indent,outdent,|,undo,redo,|,justifyleft,justifycenter,justifyright,justifyfull,|,link,unlink,|,charmap", theme_advanced_buttons2 : "", theme_advanced_buttons3 :"", theme_advanced_disable : "image,anchor,cleanup,help,code,hr,removeformat,sub,sup", theme_advanced_resizing : true, paste_text_use_dialog : true, relative_urls : false, remove_script_host : false }); </script> <!-- /TinyMCE --> i have added "autoresize" to plugins list but my editors not resize while i writing, they simply scroll. I have multiple editor in the same page. What's wrong with my code?

  Read the article

• Which of these algorithms is best for my goal?

  - by JonathonG

  I have created a program that restricts the mouse to a certain region based on a black/white bitmap. The program is 100% functional as-is, but uses an inaccurate, albeit fast, algorithm for repositioning the mouse when it strays outside the area. Currently, when the mouse moves outside the area, basically what happens is this: A line is drawn between a pre-defined static point inside the region and the mouse's new position. The point where that line intersects the edge of the allowed area is found. The mouse is moved to that point. This works, but only works perfectly for a perfect circle with the pre-defined point set in the exact center. Unfortunately, this will never be the case. The application will be used with a variety of rectangles and irregular, amorphous shapes. On such shapes, the point where the line drawn intersects the edge will usually not be the closest point on the shape to the mouse. I need to create a new algorithm that finds the closest point to the mouse's new position on the edge of the allowed area. I have several ideas about this, but I am not sure of their validity, in that they may have far too much overhead. While I am not asking for code, it might help to know that I am using Objective C / Cocoa, developing for OS X, as I feel the language being used might affect the efficiency of potential methods. My ideas are: Using a bit of trigonometry to project lines would work, but that would require some kind of intense algorithm to test every point on every line until it found the edge of the region... That seems too resource intensive since there could be something like 200 lines that would have each have to have as many as 200 pixels checked for black/white.... Using something like an A* pathing algorithm to find the shortest path to a black pixel; however, A* seems resource intensive, even though I could probably restrict it to only checking roughly in one direction. It also seems like it will take more time and effort than I have available to spend on this small portion of the much larger project I am working on, correct me if I am wrong and it would not be a significant amount of code (100 lines or around there). Mapping the border of the region before the application begins running the event tap loop. I think I could accomplish this by using my current line-based algorithm to find an edge point and then initiating an algorithm that checks all 8 pixels around that pixel, finds the next border pixel in one direction, and continues to do this until it comes back to the starting pixel. I could then store that data in an array to be used for the entire duration of the program, and have the mouse re-positioning method check the array for the closest pixel on the border to the mouse target position. That last method would presumably execute it's initial border mapping fairly quickly. (It would only have to map between 2,000 and 8,000 pixels, which means 8,000 to 64,000 checked, and I could even permanently store the data to make launching faster.) However, I am uncertain as to how much overhead it would take to scan through that array for the shortest distance for every single mouse move event... I suppose there could be a shortcut to restrict the number of elements in the array that will be checked to a variable number starting with the intersecting point on the line (from my original algorithm), and raise/lower that number to experiment with the overhead/accuracy tradeoff. Please let me know if I am over thinking this and there is an easier way that will work just fine, or which of these methods would be able to execute something like 30 times per second to keep mouse movement smooth, or if you have a better/faster method. I've posted relevant parts of my code below for reference, and included an example of what the area might look like. (I check for color value against a loaded bitmap that is black/white.) // // This part of my code runs every single time the mouse moves. // CGPoint point = CGEventGetLocation(event); float tX = point.x; float tY = point.y; if( is_in_area(tX,tY, mouse_mask)){ // target is inside O.K. area, do nothing }else{ CGPoint target; //point inside restricted region: float iX = 600; // inside x float iY = 500; // inside y // delta to midpoint between iX,iY and tX,tY float dX; float dY; float accuracy = .5; //accuracy to loop until reached do { dX = (tX-iX)/2; dY = (tY-iY)/2; if(is_in_area((tX-dX),(tY-dY),mouse_mask)){ iX += dX; iY += dY; } else { tX -= dX; tY -= dY; } } while (abs(dX)>accuracy || abs(dY)>accuracy); target = CGPointMake(roundf(tX), roundf(tY)); CGDisplayMoveCursorToPoint(CGMainDisplayID(),target); } Here is "is_in_area(int x, int y)" : bool is_in_area(NSInteger x, NSInteger y, NSBitmapImageRep *mouse_mask){ NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSUInteger pixel[4]; [mouse_mask getPixel:pixel atX:x y:y]; if(pixel[0]!= 0){ [pool release]; return false; } [pool release]; return true; }

  Read the article

• Different background color for multiple filetypes in vim

  - by puk

  Is it possible to have different background colors in vim (ie. one light, one dark) when dealing with files with multiple filetypes (ie. :set ft=html.php)? In PHP code with HTML embedded, it can be difficult to see one single PHP statement amongst dozens of HTML lines, see below. I'll settle for anything, be it different bg color, a marker in the margin, a second left margin (one vim plugin does this for marks), maybe highlighting the <?php tag for example (although that's less than ideal) EDIT: I don't think this is possible at the syntax level as the syntax appears to use a limited number of elements (String, Function, Identifier...). This is no doubt to allow for the easy integration with colorschemes. SyntaxAttr is a good plugin to demonstrate this. Put it over any part of the code and it will tell you what syntax group it belongs to.

  Read the article

• Starting an HTML canvas game with no graphics skills

  - by Jacob

  I want to do some hobby game development, but I have some unfortunate handicaps that have me stuck in indecision; I have no artistic talent, and I also have no experience with 3D graphics. But this is just a hobby project that might not go anywhere, so I want to develop the stuff I care about; if the game shows good potential, my graphic "stubs" can be replaced with something more sophisticated. I do, however, want my graphics engine to render something approximate to the end goal. The game is tile-based, with each tile being a square. Each tile also has an elevation. My target platform (subject to modification) is JavaScript rendering to the HTML 5 canvas, either with a 2D or WebGL context. My question to those of you with game development experience is whether it's easier to develop an isometric game using a 2D graphics engine and sprites or a 3D game using rudimentary 3D primitives and basic textures? I realize that there are limitations to isometric projection, but if it makes developing my throwaway graphics engine easier, I'm OK with the visual warts that would be introduced. Or is representing a 3D world with an actual 3D engine easier?

  Read the article

• The actual difference between styesheet in the header and a seperate file

  - by David Knight

  Am wondering if someone can give me an opinion on this. I have always been taught to have all of the CSS in a separate file that is referenced from the head of the page. Reading this article http://www.lukew.com/ff/entry.asp?1792 the author is talking about making the Guardian website responsive. One of the things he notes they did to make the site faster and more resilient is to add the CSS inline into the header, thus reducing HTTP requests. Now this got me thinking about the right/best/fastest way of using the CSS If you have one main CSS file, its going to be called and read by the site on every page, no mater how big it is. So with that in mind, Im actually starting to think its better to just inline the whole style sheet and remove one HTTP roundtrip. I know for the purposes of neatness and being able to edit the file a seperate file is better. But which would you recommend and which do you think is faster? Thanks!

  Read the article

• Design pattern and best practices

  - by insane-36

  I am an iphone developer. I am quite confident on developing iphone application with some minimal feature. I would consider myself as a fair application developer but the code I write is not so much structured. I make vey little use of MVC because I dont seem to find places to impose MVC. Most of the time, I create application with viewcontrollers and very few models only. How could I improve the skill for making my code more reusable, standard, easy and maintainable. I have seen few books on design patterns and tried few chapters myself but I dont seem to skip my habit. I know few of them but I am not being able to apply those patterns into my app. What is the best way to learn the design patterns and coding habit. Any kind of suggestion is warmly welcomed.

  Read the article

• How do I start correctly in building database classes in c#?

  - by e4rthdog

  I am new in C# programming and in OOP. I need to dive into web applications for my company, and I need to do it fast and correct. So even that I know ASP.NET MVC is the way to go, I want to start with some simple applications with ASP.NET Webforms and then advance to MVC logic. Also regarding my db classes: I plan to create common database classes in order to be able to use them either from WinForms or ASP.NET applications. I also know that the way to go is to learn about ORM and EF. BUT I also want to start from where I am feeling comfortable and that is the traditional ADO.NET way. So about my Data Access Layer classes: Should I return my results in datasets or arraylists/lists? Should my methods do their own connect/disconnect from the db, or have separate methods and let the application maintain the connection?

  Read the article

• Is ORM an Anti-Pattern?

  - by derphil

  I had a very stimulating and interessting discussion with a colleague about ORM and it's Pros and Cons. In my opinion, an ORM is useful only in the rarest cases. At least in my experience. But I don't want to list my own arguments at this time. So I ask you, what do you think about ORM? What are the Pros and the Cons? P.S. I've posted this "question" yesterday on Stackoverflow, but some of the user think, that this should better posted here.

  Read the article

• Can I instruct the browser not to look for a favicon?

  - by Peter Boughton

  I have a website that doesn't have/need a favicon. Is there a way to instruct the browser not to waste a request looking for /favicon.ico ? I don't mean filtering logs, but something client-side, like this: <link rel="shortcut icon" href="about:blank" /> That appears to work, but I'm not in a position to do comprehensive tests, (and search engines are being unhelpful). Can anyone confirm if this is a valid method, or provide a suitable alternative?

  Read the article

• Flexi Slider 2 Ipad showing images underneath main slider image but all other os are fine [closed]

  - by David Buckley

  I am using the Flexi Slider 2 for the jquery slider on this test page but for some reason on the ipad it shows all images in a list and doesnt appear to load the jquery but if you rotate the ipad it works any ideas would be greatly appreciate please forgive my english im a programmer not an english lecture. http://colintest.webdeveloperbelfast.com/donate.php it is not spam their functions the client is wanting the demo u guys take things so bloddy littler when a person is asking for help please do not use the paypal buttons their only their for demo purpose this is not spam

  Read the article

• How to make browser offer "remember password"

  - by Alois Mahdal

  What properties login form needs to have to trigger "remember password" for all (or most) browsers? Background: For years I have been using Opera, and the rule has been that almost anything that looks like login form triggers this feature. Now I'm exploring other browsers, and surprisingly find that one of login forms I visit most often, Roundcube login page, does not trigger this feature neither in Chromium nor Firefox (tried various versions and page setups of RC). Since it's on my VPS, I could patch it up and eventually even send that to RC development team, but I have the unnerving feeling that this must have been solved over and over, and it's just me being blind or something. So again: is there any consensus between browser developer as to when this featue should be triggered? Is there a best practice for webmasters to tell the browser "this is the login page"? Or are all browsers doing their own heuristics?

  Read the article

• How can I decrease relevancy of Creative Commons footer text? (In Google Webmaster Tools)

  - by anonymous coward

  I know that I may just have to link the image to make this happen, but I figured it was worth asking, just in case there's some other semantic markup or tips I could use... I have a site that uses the textual Creative Commons blurb in the footer. The markup is like so: <div class="footer"> <!-- snip --> <!-- Creative Commons License --> <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-sa/3.0/us/80x15.png" /></a><br />This work by <a xmlns:cc="http://creativecommons.org/ns#" href="http://www.xmemphisx.com/" property="cc:attributionName" rel="cc:attributionURL">xMEMPHISx.com</a> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/us/">Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License</a>. <!-- /Creative Commons License --> </div> Within Google Webmaster Tools, the list of relevant keywords is heavily saturated with the text from that blurb. For instance, 50% of my top-ten most relevant keywords (including the site name): [site name] license [keyword] commons creative [keyword] alike [keyword] attribution [keyword] I have not done any extensive testing to find out rather or not this list even matters, and so far this doesn't impact performance in any way. The site is well designed for humans, and it is as findable as it needs to be at the moment. But, out of mostly curiosity: Do you have any tips for decreasing the relevancy of the text from the Creative Commons footer blurb?

  Read the article

• What is correct heading setup for subpages

  - by user1010609

  What is the best for seo of the following: using <h1>keyword</h1> in layout and putting each subpage title in </h2> using <h1>keyword</h1> only for main page and on each subpage replace it to <h2>keyword</h2> and using h1 tags for subapge title not using <h1>keyword</h1> on any of the pages instead put keyword in in header and use for each subpage and using <h1>keyword + something for main page title</h1> None of the above (please go into as much details)

  Read the article

• How do we keep dependent data structures up to date?

  - by Geo

  Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, but how can we manage the complexity of updating the graphs when the parse tree is modified? We know exactly how the tree has been modified, but how can the change be propagated to the other trees in a way that doesn't become difficult to manage? Naturally the dependent graph can be updated by simply reconstructing it from scratch every time the first graph changes, but then there would be no way of knowing the details of the changes in the dependent graph. I currently have four ways to attempt to solve this problem, but each one has difficulties. Nodes of the dependent tree each observe the relevant nodes of the original tree, updating themselves and the observer lists of original tree nodes as necessary. The conceptual complexity of this can become daunting. Each node of the original tree has a list of the dependent tree nodes that specifically depend upon it, and when the node changes it sets a flag on the dependent nodes to mark them as dirty, including the parents of the dependent nodes all the way down to the root. After each change we run an algorithm that is much like the algorithm for constructing the dependent graph from scratch, but it skips over any clean node and reconstructs each dirty node, keeping track of whether the reconstructed node is actually different from the dirty node. This can also get tricky. We can represent the logical connection between the original graph and the dependent graph as a data structure, like a list of constraints, perhaps designed using a declarative language. When the original graph changes we need only scan the list to discover which constraints are violated and how the dependent tree needs to change to correct the violation, all encoded as data. We can reconstruct the dependent graph from scratch as though there were no existing dependent graph, and then compare the existing graph and the new graph to discover how it has changed. I'm sure this is the easiest way because I know there are algorithms available for detecting differences, but they are all quite computationally expensive and in principle it seems unnecessary so I'm deliberately avoiding this option. What is the right way to deal with these sorts of problems? Surely there must be a design pattern that makes this whole thing almost easy. It would be nice to have a good solution for every problem of this general description. Does this class of problem have a name?

  Read the article

< Previous Page | 152 153 154 155 156 157 158 159 160 161 162 163  | Next Page >