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  • pdo connection scope

    - by Scarface
    Hey guys I have a connection class I found for pdo. I am calling the connection method on the page that the file is included on. The problem is that within functions the $conn variable is not defined even though I stated the method was public (bare with me I am very new to OOP), and I was wondering if anyone had an elegant solution other then using global in every function. Any suggestions are greatly appreciated. CONNECTION class PDOConnectionFactory{ // receives the connection public $con = null; // swich database? public $dbType = "mysql"; // connection parameters // when it will not be necessary leaves blank only with the double quotations marks "" public $host = "localhost"; public $user = "user"; public $senha = "password"; public $db = "database"; // arrow the persistence of the connection public $persistent = false; // new PDOConnectionFactory( true ) <--- persistent connection // new PDOConnectionFactory() <--- no persistent connection public function PDOConnectionFactory( $persistent=false ){ // it verifies the persistence of the connection if( $persistent != false){ $this->persistent = true; } } public function getConnection(){ try{ // it carries through the connection $this->con = new PDO($this->dbType.":host=".$this->host.";dbname=".$this->db, $this->user, $this->senha, array( PDO::ATTR_PERSISTENT => $this->persistent ) ); // carried through successfully, it returns connected return $this->con; // in case that an error occurs, it returns the error; }catch ( PDOException $ex ){ echo "We are currently experiencing technical difficulties. We have a bunch of monkies working really hard to fix the problem. Check back soon: ".$ex->getMessage(); } } // close connection public function Close(){ if( $this->con != null ) $this->con = null; } } PAGE USED ON include("includes/connection.php"); $db = new PDOConnectionFactory(); $conn = $db->getConnection(); function test(){ try{ $sql = 'SELECT * FROM topic'; $stmt = $conn->prepare($sql); $result=$stmt->execute(); } catch(PDOException $e){ echo $e->getMessage(); } } test();

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  • How can I enable a debugging mode via a command-line switch for my Perl program?

    - by Michael Mao
    I am learning Perl in a "head-first" manner. I am absolutely a newbie in this language: I am trying to have a debug_mode switch from CLI which can be used to control how my script works, by switching certain subroutines "on and off". And below is what I've got so far: #!/usr/bin/perl -s -w # purpose : make subroutine execution optional, # which is depending on a CLI switch flag use strict; use warnings; use constant DEBUG_VERBOSE => "v"; use constant DEBUG_SUPPRESS_ERROR_MSGS => "s"; use constant DEBUG_IGNORE_VALIDATION => "i"; use constant DEBUG_SETPPING_COMPUTATION => "c"; our ($debug_mode); mainMethod(); sub mainMethod # () { if(!$debug_mode) { print "debug_mode is OFF\n"; } elsif($debug_mode) { print "debug_mode is ON\n"; } else { print "OMG!\n"; exit -1; } checkArgv(); printErrorMsg("Error_Code_123", "Parsing Error at..."); verbose(); } sub checkArgv #() { print ("Number of ARGV : ".(1 + $#ARGV)."\n"); } sub printErrorMsg # ($error_code, $error_msg, ..) { if(defined($debug_mode) && !($debug_mode =~ DEBUG_SUPPRESS_ERROR_MSGS)) { print "You can only see me if -debug_mode is NOT set". " to DEBUG_SUPPRESS_ERROR_MSGS\n"; die("terminated prematurely...\n") and exit -1; } } sub verbose # () { if(defined($debug_mode) && ($debug_mode =~ DEBUG_VERBOSE)) { print "Blah blah blah...\n"; } } So far as I can tell, at least it works...: the -debug_mode switch doesn't interfere with normal ARGV the following commandlines work: ./optional.pl ./optional.pl -debug_mode ./optional.pl -debug_mode=v ./optional.pl -debug_mode=s However, I am puzzled when multiple debug_modes are "mixed", such as: ./optional.pl -debug_mode=sv ./optional.pl -debug_mode=vs I don't understand why the above lines of code "magically works". I see both of the "DEBUG_VERBOS" and "DEBUG_SUPPRESS_ERROR_MSGS" apply to the script, which is fine in this case. However, if there are some "conflicting" debug modes, I am not sure how to set the "precedence of debug_modes"? Also, I am not certain if my approach is good enough to Perlists and I hope I am getting my feet in the right direction. One biggest problem is that I now put if statements inside most of my subroutines for controlling their behavior under different modes. Is this okay? Is there a more elegant way? I know there must be a debug module from CPAN or elsewhere, but I want a real minimal solution that doesn't depend on any other module than the "default". And I cannot have any control on the environment where this script will be executed...

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  • How to facebook getuser() after login with javascript SDK

    - by user1848205
    So I have to ask for extended permission by clicking the enter button, but after the login is necessary to refresh the page in order to display the app. Here's my code: <?php require 'facebook.php'; $facebook = new Facebook(array( 'appId' => '< THE APPID >', 'secret' => '< THE SECRET >', 'cookie' => true, )); $user = $facebook->getUser(); if ($user) { try { $user_profile = $facebook->api('/me'); } catch (FacebookApiException $e) { error_log($e); $user = null; } } ?> <body> <div id="fb-root"></div> <script> window.fbAsyncInit = function() { FB.init({ appId : '< THE APPID >', status : true, cookie : true, xfbml : true }); // Additional initialization code such as adding Event Listeners goes here $('#btn-enter').click(function(){ login(); }); }; (function(d){ var js, id = 'facebook-jssdk', ref = d.getElementsByTagName('script')[0]; if (d.getElementById(id)) {return;} js = d.createElement('script'); js.id = id; js.async = true; js.src = "//connect.facebook.net/en_US/all.js"; ref.parentNode.insertBefore(js, ref); }(document)); function login() { FB.login(function(response) { if (response.authResponse) { // connected } else { // cancelled } //}); }, {scope: 'read_friendlists,friends_photos,publish_stream'}); } </script> <?php if ($user): ?> <!--Here is my APP--> <?php else: ?> <a id="btn-enter">Enter</a> <?php endif ?> Is there a better way to do this ? What works for me is: function login() { FB.login(function(response) { if (response.authResponse) { top.location.href='https://the_app_url'; } else { } //}); }, {scope: 'read_friendlists,friends_photos,publish_stream'}); } But this causes the entire page to refresh and is not 'elegant' per se...

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  • C# 4: The Curious ConcurrentDictionary

    - by James Michael Hare
    In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking.  The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations.  In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did?  Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests.  Obviously there's many things we can do with a dictionary.  One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache.  So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor.  This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit").  However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss").  So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10:  11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14:  15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19:  20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22:  23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward.  Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: };                    Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete.  Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances.  All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8:  9:  10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17:  18:  19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category.  The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend.  In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution.  But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds".  So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it).  And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here.  I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well.  This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us?  Well, as in all things, ConcurrentDictionary is not a panacea.  It won't solve all your woes and it shouldn't be the only Dictionary you ever use.  So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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  • Parallelism in .NET – Part 6, Declarative Data Parallelism

    - by Reed
    When working with a problem that can be decomposed by data, we have a collection, and some operation being performed upon the collection.  I’ve demonstrated how this can be parallelized using the Task Parallel Library and imperative programming using imperative data parallelism via the Parallel class.  While this provides a huge step forward in terms of power and capabilities, in many cases, special care must still be given for relative common scenarios. C# 3.0 and Visual Basic 9.0 introduced a new, declarative programming model to .NET via the LINQ Project.  When working with collections, we can now write software that describes what we want to occur without having to explicitly state how the program should accomplish the task.  By taking advantage of LINQ, many operations become much shorter, more elegant, and easier to understand and maintain.  Version 4.0 of the .NET framework extends this concept into the parallel computation space by introducing Parallel LINQ. Before we delve into PLINQ, let’s begin with a short discussion of LINQ.  LINQ, the extensions to the .NET Framework which implement language integrated query, set, and transform operations, is implemented in many flavors.  For our purposes, we are interested in LINQ to Objects.  When dealing with parallelizing a routine, we typically are dealing with in-memory data storage.  More data-access oriented LINQ variants, such as LINQ to SQL and LINQ to Entities in the Entity Framework fall outside of our concern, since the parallelism there is the concern of the data base engine processing the query itself. LINQ (LINQ to Objects in particular) works by implementing a series of extension methods, most of which work on IEnumerable<T>.  The language enhancements use these extension methods to create a very concise, readable alternative to using traditional foreach statement.  For example, let’s revisit our minimum aggregation routine we wrote in Part 4: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re doing a very simple computation, but writing this in an imperative style.  This can be loosely translated to English as: Create a very large number, and save it in min Loop through each item in the collection. For every item: Perform some computation, and save the result If the computation is less than min, set min to the computation Although this is fairly easy to follow, it’s quite a few lines of code, and it requires us to read through the code, step by step, line by line, in order to understand the intention of the developer. We can rework this same statement, using LINQ: double min = collection.Min(item => item.PerformComputation()); Here, we’re after the same information.  However, this is written using a declarative programming style.  When we see this code, we’d naturally translate this to English as: Save the Min value of collection, determined via calling item.PerformComputation() That’s it – instead of multiple logical steps, we have one single, declarative request.  This makes the developer’s intentions very clear, and very easy to follow.  The system is free to implement this using whatever method required. Parallel LINQ (PLINQ) extends LINQ to Objects to support parallel operations.  This is a perfect fit in many cases when you have a problem that can be decomposed by data.  To show this, let’s again refer to our minimum aggregation routine from Part 4, but this time, let’s review our final, parallelized version: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Here, we’re doing the same computation as above, but fully parallelized.  Describing this in English becomes quite a feat: Create a very large number, and save it in min Create a temporary object we can use for locking Call Parallel.ForEach, specifying three delegates For the first delegate: Initialize a local variable to hold the local state to a very large number For the second delegate: For each item in the collection, perform some computation, save the result If the result is less than our local state, save the result in local state For the final delegate: Take a lock on our temporary object to protect our min variable Save the min of our min and local state variables Although this solves our problem, and does it in a very efficient way, we’ve created a set of code that is quite a bit more difficult to understand and maintain. PLINQ provides us with a very nice alternative.  In order to use PLINQ, we need to learn one new extension method that works on IEnumerable<T> – ParallelEnumerable.AsParallel(). That’s all we need to learn in order to use PLINQ: one single method.  We can write our minimum aggregation in PLINQ very simply: double min = collection.AsParallel().Min(item => item.PerformComputation()); By simply adding “.AsParallel()” to our LINQ to Objects query, we converted this to using PLINQ and running this computation in parallel!  This can be loosely translated into English easily, as well: Process the collection in parallel Get the Minimum value, determined by calling PerformComputation on each item Here, our intention is very clear and easy to understand.  We just want to perform the same operation we did in serial, but run it “as parallel”.  PLINQ completely extends LINQ to Objects: the entire functionality of LINQ to Objects is available.  By simply adding a call to AsParallel(), we can specify that a collection should be processed in parallel.  This is simple, safe, and incredibly useful.

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  • MVC 3 AdditionalMetadata Attribute with ViewBag to Render Dynamic UI

    - by Steve Michelotti
    A few months ago I blogged about using Model metadata to render a dynamic UI in MVC 2. The scenario in the post was that we might have a view model where the questions are conditionally displayed and therefore a dynamic UI is needed. To recap the previous post, the solution was to use a custom attribute called [QuestionId] in conjunction with an “ApplicableQuestions” collection to identify whether each question should be displayed. This allowed me to have a view model that looked like this: 1: [UIHint("ScalarQuestion")] 2: [DisplayName("First Name")] 3: [QuestionId("NB0021")] 4: public string FirstName { get; set; } 5: 6: [UIHint("ScalarQuestion")] 7: [DisplayName("Last Name")] 8: [QuestionId("NB0022")] 9: public string LastName { get; set; } 10: 11: [UIHint("ScalarQuestion")] 12: [QuestionId("NB0023")] 13: public int Age { get; set; } 14: 15: public IEnumerable<string> ApplicableQuestions { get; set; } At the same time, I was able to avoid repetitive IF statements for every single question in my view: 1: <%: Html.EditorFor(m => m.FirstName, new { applicableQuestions = Model.ApplicableQuestions })%> 2: <%: Html.EditorFor(m => m.LastName, new { applicableQuestions = Model.ApplicableQuestions })%> 3: <%: Html.EditorFor(m => m.Age, new { applicableQuestions = Model.ApplicableQuestions })%> by creating an Editor Template called “ScalarQuestion” that encapsulated the IF statement: 1: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %> 2: <%@ Import Namespace="DynamicQuestions.Models" %> 3: <%@ Import Namespace="System.Linq" %> 4: <% 5: var applicableQuestions = this.ViewData["applicableQuestions"] as IEnumerable<string>; 6: var questionAttr = this.ViewData.ModelMetadata.ContainerType.GetProperty(this.ViewData.ModelMetadata.PropertyName).GetCustomAttributes(typeof(QuestionIdAttribute), true) as QuestionIdAttribute[]; 7: string questionId = null; 8: if (questionAttr.Length > 0) 9: { 10: questionId = questionAttr[0].Id; 11: } 12: if (questionId != null && applicableQuestions.Contains(questionId)) { %> 13: <div> 14: <%: Html.Label("") %> 15: <%: Html.TextBox("", this.Model)%> 16: </div> 17: <% } %> You might want to go back and read the full post in order to get the full context. MVC 3 offers a couple of new features that make this scenario more elegant to implement. The first step is to use the new [AdditionalMetadata] attribute which, so far, appears to be an under appreciated new feature of MVC 3. With this attribute, I don’t need my custom [QuestionId] attribute anymore - now I can just write my view model like this: 1: [UIHint("ScalarQuestion")] 2: [DisplayName("First Name")] 3: [AdditionalMetadata("QuestionId", "NB0021")] 4: public string FirstName { get; set; } 5:   6: [UIHint("ScalarQuestion")] 7: [DisplayName("Last Name")] 8: [AdditionalMetadata("QuestionId", "NB0022")] 9: public string LastName { get; set; } 10:   11: [UIHint("ScalarQuestion")] 12: [AdditionalMetadata("QuestionId", "NB0023")] 13: public int Age { get; set; } Thus far, the documentation seems to be pretty sparse on the AdditionalMetadata attribute. It’s buried in the Other New Features section of the MVC 3 home page and, after showing the attribute on a view model property, it just says, “This metadata is made available to any display or editor template when a product view model is rendered. It is up to you to interpret the metadata information.” But what exactly does it look like for me to “interpret the metadata information”? Well, it turns out it makes the view much easier to work with. Here is the re-implemented ScalarQuestion template updated for MVC 3 and Razor: 1: @{ 2: object questionId; 3: ViewData.ModelMetadata.AdditionalValues.TryGetValue("QuestionId", out questionId); 4: if (ViewBag.applicableQuestions.Contains((string)questionId)) { 5: <div> 6: @Html.LabelFor(m => m) 7: @Html.TextBoxFor(m => m) 8: </div> 9: } 10: } So we’ve gone from 17 lines of code (in the MVC 2 version) to about 7-8 lines of code here. The first thing to notice is that in MVC 3 we now have a property called “AdditionalValues” that hangs off of the ModelMetadata property. This is automatically populated by any [AdditionalMetadata] attributes on the property. There is no more need for me to explicitly write Reflection code to GetCustomAttributes() and then check to see if those attributes were present. I can just call TryGetValue() on the dictionary to see if they were present. Secondly, the “applicableQuestions” anonymous type that I passed in from the calling view – in MVC 3 I now have a dynamic ViewBag property where I can just “dot into” the applicableQuestions with a nicer syntax than dictionary square bracket syntax. And there’s no problems calling the Contains() method on this dynamic object because at runtime the DLR has resolved that it is a generic List<string>. At this point you might be saying that, yes the view got much nicer than the MVC 2 version, but my view model got slightly worse.  In the previous version I had a nice [QuestionId] attribute but now, with the [AdditionalMetadata] attribute, I have to type the string “QuestionId” for every single property and hope that I don’t make a typo. Well, the good news is that it’s easy to create your own attributes that can participate in the metadata’s additional values. The key is that the attribute must implement that IMetadataAware interface and populate the AdditionalValues dictionary in the OnMetadataCreated() method: 1: public class QuestionIdAttribute : Attribute, IMetadataAware 2: { 3: public string Id { get; set; } 4:   5: public QuestionIdAttribute(string id) 6: { 7: this.Id = id; 8: } 9:   10: public void OnMetadataCreated(ModelMetadata metadata) 11: { 12: metadata.AdditionalValues["QuestionId"] = this.Id; 13: } 14: } This now allows me to encapuslate my “QuestionId” string in just one place and get back to my original attribute which can be used like this: [QuestionId(“NB0021”)]. The [AdditionalMetadata] attribute is a powerful and under-appreciated new feature of MVC 3. Combined with the dynamic ViewBag property, you can do some really interesting things with your applications with less code and ceremony.

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  • Creating A SharePoint Parent/Child List Relationship&ndash; SharePoint 2010 Edition

    - by Mark Rackley
    Hey blog readers… It has been almost 2 years since I posted my most read blog on creating a Parent/Child list relationship in SharePoint 2007: Creating a SharePoint List Parent / Child Relationship - Out of the Box And then a year ago I improved on my method and redid the blog post… still for SharePoint 2007: Creating a SharePoint List Parent/Child Relationship – VIDEO REMIX Since then many of you have been asking me how to get this to work in SharePoint 2010, and frankly I have just not had time to look into it. I wish I could have jumped into this sooner, but have just recently began to look at it. Well.. after all this time I have actually come up with two solutions that work, neither of them are as clean as I’d like them to be, but I wanted to get something in your hands that you can start using today. Hopefully in the coming weeks and months I’ll be able to improve upon this further and give you guys some better options. For the most part, the process is identical to the 2007 process, but you have probably found out that the list view web parts in 2010 behave differently, and getting the Parent ID to your new child form can be a pain in the rear (at least that’s what I’ve discovered). Anyway, like I said, I have found a couple of solutions that work. If you know of a better one, please let us know as it bugs me that this not as eloquent as my 2007 implementation. Getting on the same page First thing I’d recommend is recreating this blog: Creating a SharePoint List Parent/Child Relationship – VIDEO REMIX in SharePoint 2010… There are some vague differences, but it’s basically the same…  Here’s a quick video of me doing this in SP 2010: Creating Lists necessary for this blog post Now that you have the lists created, lets set up the New Time form to use a QueryString variable to populate the Parent ID field: Creating parameters in Child’s new item form to set parent ID Did I talk fast enough through both of those videos? Hopefully by now that stuff is old hat to you, but I wanted to make sure everyone could get on the same page.  Okay… let’s get started. Solution 1 – XSLTListView with Javascript This solution is the more elegant of the two, however it does require the use of a little javascript.  The other solution does not use javascript, but it also doesn’t use the pretty new SP 2010 pop-ups.  I’ll let you decide which you like better. The basic steps of this solution are: Inserted a Related Item View Insert a ContentEditorWebPart Insert script in ContentEditorWebPart that pulls the ID from the Query string and calls the method to insert a new item on the child entry form Hide the toolbar from data view to remove “add new item” link. Again, you don’t HAVE to use a CEWP, you could just put the javascript directly in the page using SPD.  Anyway, here is how I did it: Using Related Item View / JavaScript Here’s the JavaScript I used in my Content Editor Web Part: <script type="text/javascript"> function NewTime() { // Get the Query String values and split them out into the vals array var vals = new Object(); var qs = location.search.substring(1, location.search.length); var args = qs.split("&"); for (var i=0; i < args.length; i++) { var nameVal = args[i].split("="); var temp = unescape(nameVal[1]).split('+'); nameVal[1] = temp.join(' '); vals[nameVal[0]] = nameVal[1]; } var issueID = vals["ID"]; //use this to bring up the pretty pop up NewItem2(event,"http://sp2010dev:1234/Lists/Time/NewForm.aspx?IssueID=" + issueID); //use this to open a new window //window.location="http://sp2010dev:1234/Lists/Time/NewForm.aspx?IssueID=" + issueID; } </script> Solution 2 – DataFormWebPart and exact same 2007 Process This solution is a little more of a hack, but it also MUCH more close to the process we did in SP 2007. So, if you don’t mind not having the pretty pop-up and prefer the comforts of what you are used to, you can give this one a try.  The basics steps are: Insert a DataFormWebPart instead of the List Data View Create a Parameter on DataFormWebPart to store “ID” Query String Variable Filter DataFormWebPart using Parameter Insert a link at bottom of DataForm Web part that points to the Child’s new item form and passes in the Parent Id using the Parameter. See.. like I told you, exact same process as in 2007 (except using the DataFormWeb Part). The DataFormWebPart also requires a lot more work to make it look “pretty” but it’s just table rows and cells, and can be configured pretty painlessly.  Here is that video: Using DataForm Web Part One quick update… if you change the link in this solution from: <tr> <td><a href="http://sp2010dev:1234/Lists/Time/NewForm.aspx?IssueID={$IssueIDParam}">Click here to create new item...</a> </td> </tr> to: <tr> <td> <a href="javascript:NewItem2(event,'http://sp2010dev:1234/Lists/Time/NewForm.aspx?IssueID={$IssueIDParam}');">Click here to create new item...</a> </td> </tr> It will open up in the pretty pop up and act the same as solution one… So… both Solutions will now behave the same to the end user. Just depends on which you want to implement. That’s all for now… Remember in both solutions when you have them working, you can make the “IssueID” invisible to users by using the “ms-hidden” class (it’s my previous blog post on the subject up there). That’s basically all there is to it! No pithy or witty closing this time… I am sorry it took me so long to dive into this and I hope your questions are answered. As I become more polished myself I will try to come up with a cleaner solution that will make everyone happy… As always, thanks for taking the time to stop by.

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  • Establishing WebLogic Server HTTPS Trust of IIS Using a Microsoft Local Certificate Authority

    - by user647124
    Everyone agrees that self-signed and demo certificates for SSL and HTTPS should never be used in production and preferred not to be used elsewhere. Most self-signed and demo certificates are provided by vendors with the intention that they are used only to integrate within the same environment. In a vendor’s perfect world all application servers in a given enterprise are from the same vendor, which makes this lack of interoperability in a non-production environment an advantage. For us working in the real world, where not only do we not use a single vendor everywhere but have to make do with self-signed certificates for all but production, testing HTTPS between an IIS ASP.NET service provider and a WebLogic J2EE consumer application can be very frustrating to set up. It was for me, especially having found many blogs and discussion threads where various solutions were described but did not quite work and were all mostly similar but just a little bit different. To save both you and my future (who always seems to forget the hardest-won lessons) all of the pain and suffering, I am recording the steps that finally worked here for reference and sanity. How You Know You Need This The first cold clutches of dread that tells you it is going to be a long day is when you attempt to a WSDL published by IIS in WebLogic over HTTPS and you see the following: <Jul 30, 2012 2:51:31 PM EDT> <Warning> <Security> <BEA-090477> <Certificate chain received from myserver.mydomain.com - 10.555.55.123 was not trusted causing SSL handshake failure.> weblogic.wsee.wsdl.WsdlException: Failed to read wsdl file from url due to -- javax.net.ssl.SSLKeyException: [Security:090477]Certificate chain received from myserver02.mydomain.com - 10.555.55.123 was not trusted causing SSL handshake failure. The above is what started a three day sojourn into searching for a solution. Even people who had solved it before would tell me how they did, and then shrug when I demonstrated that the steps did not end in the success they claimed I would experience. Rather than torture you with the details of everything I did that did not work, here is what finally did work. Export the Certificates from IE First, take the offending WSDL URL and paste it into IE (if you have an internal Microsoft CA, you have IE, even if you don’t use it in favor of some other browser). To state the semi-obvious, if you received the error above there is a certificate configured for the IIS host of the service and the SSL port has been configured properly. Otherwise there would be a different error, usually about the site not found or connection failed. Once the WSDL loads, to the right of the address bar there will be a lock icon. Click the lock and then click View Certificates in the resulting dialog (if you do not have a lock icon but do have a Certificate Error message, see http://support.microsoft.com/kb/931850 for steps to install the certificate then you can continue from the point of finding the lock icon). Figure 1: View Certificates in IE Next, select the Details tab in the resulting dialog Figure 2: Use Certificate Details to Export Certificate Click Copy to File, then Next, then select the Base-64 encoded option for the format Figure 3: Select the Base-64 encoded option for the format For the sake of simplicity, I choose to save this to the root of the WebLogic domain. It will work from anywhere, but later you will need to type in the full path rather than just the certificate name if you save it elsewhere. Figure 4: Browse to Save Location Figure 5: Save the Certificate to the Domain Root for Convenience This is the point where I ran into some confusion. Some articles mentioned exporting the entire chain of certificates. This supposedly works for some types of certificates, or if you have a few other tools and the time to learn them. For the SSL experts out there, they already have these tools, know how to use them well, and should not be wasting their time reading this article meant for folks who just want to get things wired up and back to unit testing and development. For the rest of us, the easiest way to make sure things will work is to just export all the links in the chain individually and let WebLogic Server worry about re-assembling them into a chain (which it does quite nicely). While perhaps not the most elegant solution, the multi-step process is easy to repeat and uses only tools that are immediately available and require no learning curve. So… Next, go to Tools then Internet Options then the Content tab and click Certificates. Go to the Trust Root Certificate Authorities tab and find the certificate root for your Microsoft CA cert (look for the Issuer of the certificate you exported earlier). Figure 6: Trusted Root Certification Authorities Tab Export this one the same way as before, with a different name Figure 7: Use a Unique Name for Each Certificate Repeat this once more for the Intermediate Certificate tab. Import the Certificates to the WebLogic Domain Now, open an command prompt, navigate to [WEBLOGIC_DOMAIN_ROOT]\bin and execute setDomainEnv. You should then be in the root of the domain. If not, CD to the domain root. Assuming you saved the certificate in the domain root, execute the following: keytool -importcert -alias [ALIAS-1] -trustcacerts -file [FULL PATH TO .CER 1] -keystore truststore.jks -storepass [PASSWORD] An example with the variables filled in is: keytool -importcert -alias IIS-1 -trustcacerts -file microsftcert.cer -keystore truststore.jks -storepass password After several lines out output you will be prompted with: Trust this certificate? [no]: The correct answer is ‘yes’ (minus the quotes, of course). You’ll you know you were successful if the response is: Certificate was added to keystore If not, check your typing, as that is generally the source of an error at this point. Repeat this for all three of the certificates you exported, changing the [ALIAS-1] and [FULL PATH TO .CER 1] value each time. For example: keytool -importcert -alias IIS-1 -trustcacerts -file microsftcert.cer -keystore truststore.jks -storepass password keytool -importcert -alias IIS-2 -trustcacerts -file microsftcertRoot.cer -keystore truststore.jks -storepass password keytool -importcert -alias IIS-3 -trustcacerts -file microsftcertIntermediate.cer -keystore truststore.jks -storepass password In the above we created a new JKS key store. You can re-use an existing one by changing the name of the JKS file to one you already have and change the password to the one that matches that JKS file. For the DemoTrust.jks  that is included with WebLogic the password is DemoTrustKeyStorePassPhrase. An example here would be: keytool -importcert -alias IIS-1 -trustcacerts -file microsoft.cer -keystore DemoTrust.jks -storepass DemoTrustKeyStorePassPhrase keytool -importcert -alias IIS-2 -trustcacerts -file microsoftRoot.cer -keystore DemoTrust.jks -storepass DemoTrustKeyStorePassPhrase keytool -importcert -alias IIS-2 -trustcacerts -file microsoftInter.cer -keystore DemoTrust.jks -storepass DemoTrustKeyStorePassPhrase Whichever keystore you use, you can check your work with: keytool -list -keystore truststore.jks -storepass password Where “truststore.jks” and “password” can be replaced appropriately if necessary. The output will look something like this: Figure 8: Output from keytool -list -keystore Update the WebLogic Keystore Configuration If you used an existing keystore rather than creating a new one, you can restart your WebLogic Server and skip the rest of this section. For those of us who created a new one because that is the instructions we found online… Next, we need to tell WebLogic to use the JKS file (truststore.jks) we just created. Log in to the WebLogic Server Administration Console and navigate to Servers > AdminServer > Configuration > Keystores. Scroll down to “Custom Trust Keystore:” and change the value to “truststore.jks” and the value of “Custom Trust Keystore Passphrase:” and “Confirm Custom Trust Keystore Passphrase:” to the password you used when earlier, then save your changes. You will get a nice message similar to the following: Figure 9: To Be Safe, Restart Anyways The “No restarts are necessary” is somewhat of an exaggeration. If you want to be able to use the keystore you may need restart the server(s). To save myself aggravation, I always do. Your mileage may vary. Conclusion That should get you there. If there are some erroneous steps included for your situation in particular, I will offer up a semi-apology as the process described above does not take long at all and if there is one step that could be dropped from it, is still much faster than trying to figure this out from other sources.

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  • A Good Developer is So Hard to Find

    - by James Michael Hare
    Let me start out by saying I want to damn the writers of the Toughest Developer Puzzle Ever – 2. It is eating every last shred of my free time! But as I've been churning through each puzzle and marvelling at the brain teasers and trivia within, I began to think about interviewing developers and why it seems to be so hard to find good ones.  The problem is, it seems like no matter how hard we try to find the perfect way to separate the chaff from the wheat, inevitably someone will get hired who falls far short of expectations or someone will get passed over for missing a piece of trivia or a tricky brain teaser that could have been an excellent team member.   In shops that are primarily software-producing businesses or other heavily IT-oriented businesses (Microsoft, Amazon, etc) there often exists a much tighter bond between HR and the hiring development staff because development is their life-blood. Unfortunately, many of us work in places where IT is viewed as a cost or just a means to an end. In these shops, too often, HR and development staff may work against each other due to differences in opinion as to what a good developer is or what one is worth.  It seems that if you ask two different people what makes a good developer, often you will get three different opinions.   With the exception of those shops that are purely development-centric (you guys have it much easier!), most other shops have management who have very little knowledge about the development process.  Their view can often be that development is simply a skill that one learns and then once aquired, that developer can produce widgets as good as the next like workers on an assembly-line floor.  On the other side, you have many developers that feel that software development is an art unto itself and that the ability to create the most pure design or know the most obscure of keywords or write the shortest-possible obfuscated piece of code is a good coder.  So is it a skill?  An Art?  Or something entirely in between?   Saying that software is merely a skill and one just needs to learn the syntax and tools would be akin to saying anyone who knows English and can use Word can write a 300 page book that is accurate, meaningful, and stays true to the point.  This just isn't so.  It takes more than mere skill to take words and form a sentence, join those sentences into paragraphs, and those paragraphs into a document.  I've interviewed candidates who could answer obscure syntax and keyword questions and once they were hired could not code effectively at all.  So development must be more than a skill.   But on the other end, we have art.  Is development an art?  Is our end result to produce art?  I can marvel at a piece of code -- see it as concise and beautiful -- and yet that code most perform some stated function with accuracy and efficiency and maintainability.  None of these three things have anything to do with art, per se.  Art is beauty for its own sake and is a wonderful thing.  But if you apply that same though to development it just doesn't hold.  I've had developers tell me that all that matters is the end result and how you code it is entirely part of the art and I couldn't disagree more.  Yes, the end result, the accuracy, is the prime criteria to be met.  But if code is not maintainable and efficient, it would be just as useless as a beautiful car that breaks down once a week or that gets 2 miles to the gallon.  Yes, it may work in that it moves you from point A to point B and is pretty as hell, but if it can't be maintained or is not efficient, it's not a good solution.  So development must be something less than art.   In the end, I think I feel like development is a matter of craftsmanship.  We use our tools and we use our skills and set about to construct something that satisfies a purpose and yet is also elegant and efficient.  There is skill involved, and there is an art, but really it boils down to being able to craft code.  Crafting code is far more than writing code.  Anyone can write code if they know the syntax, but so few people can actually craft code that solves a purpose and craft it well.  So this is what I want to find, I want to find code craftsman!  But how?   I used to ask coding-trivia questions a long time ago and many people still fall back on this.  The thought is that if you ask the candidate some piece of coding trivia and they know the answer it must follow that they can craft good code.  For example:   What C++ keyword can be applied to a class/struct field to allow it to be changed even from a const-instance of that class/struct?  (answer: mutable)   So what do we prove if a candidate can answer this?  Only that they know what mutable means.  One would hope that this would infer that they'd know how to use it, and more importantly when and if it should ever be used!  But it rarely does!  The problem with triva questions is that you will either: Approve a really good developer who knows what some obscure keyword is (good) Reject a really good developer who never needed to use that keyword or is too inexperienced to know how to use it (bad) Approve a really bad developer who googled "C++ Interview Questions" and studied like hell but can't craft (very bad) Many HR departments love these kind of tests because they are short and easy to defend if a legal issue arrises on hiring decisions.  After all it's easy to say a person wasn't hired because they scored 30 out of 100 on some trivia test.  But unfortunately, you've eliminated a large part of your potential developer pool and possibly hired a few duds.  There are times I've hired candidates who knew every trivia question I could throw out them and couldn't craft.  And then there are times I've interviewed candidates who failed all my trivia but who I took a chance on who were my best finds ever.    So if not trivia, then what?  Brain teasers?  The thought is, these type of questions measure the thinking power of a candidate.  The problem is, once again, you will either: Approve a good candidate who has never heard the problem and can solve it (good) Reject a good candidate who just happens not to see the "catch" because they're nervous or it may be really obscure (bad) Approve a candidate who has studied enough interview brain teasers (once again, you can google em) to recognize the "catch" or knows the answer already (bad). Once again, you're eliminating good candidates and possibly accepting bad candidates.  In these cases, I think testing someone with brain teasers only tests their ability to answer brain teasers, not the ability to craft code. So how do we measure someone's ability to craft code?  Here's a novel idea: have them code!  Give them a computer and a compiler, or a whiteboard and a pen, or paper and pencil and have them construct a piece of code.  It just makes sense that if we're going to hire someone to code we should actually watch them code.  When they're done, we can judge them on several criteria: Correctness - does the candidate's solution accurately solve the problem proposed? Accuracy - is the candidate's solution reasonably syntactically correct? Efficiency - did the candidate write or use the more efficient data structures or algorithms for the job? Maintainability - was the candidate's code free of obfuscation and clever tricks that diminish readability? Persona - are they eager and willing or aloof and egotistical?  Will they work well within your team? It may sound simple, or it may sound crazy, but when I'm looking to hire a developer, I want to see them actually develop well-crafted code.

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  • SQL SERVER – Weekly Series – Memory Lane – #050

    - by Pinal Dave
    Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 Executing Remote Stored Procedure – Calling Stored Procedure on Linked Server In this example we see two different methods of how to call Stored Procedures remotely.  Connection Property of SQL Server Management Studio SSMS A very simple example of the how to build connection properties for SQL Server with the help of SSMS. Sample Example of RANKING Functions – ROW_NUMBER, RANK, DENSE_RANK, NTILE SQL Server has a total of 4 ranking functions. Ranking functions return a ranking value for each row in a partition. All the ranking functions are non-deterministic. T-SQL Script to Add Clustered Primary Key Jr. DBA asked me three times in a day, how to create Clustered Primary Key. I gave him following sample example. That was the last time he asked “How to create Clustered Primary Key to table?” 2008 2008 – TRIM() Function – User Defined Function SQL Server does not have functions which can trim leading or trailing spaces of any string at the same time. SQL does have LTRIM() and RTRIM() which can trim leading and trailing spaces respectively. SQL Server 2008 also does not have TRIM() function. User can easily use LTRIM() and RTRIM() together and simulate TRIM() functionality. http://www.youtube.com/watch?v=1-hhApy6MHM 2009 Earlier I have written two different articles on the subject Remove Bookmark Lookup. This article is as part 3 of original article. Please read the first two articles here before continuing reading this article. Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 2 Query Optimization – Remove Bookmark Lookup – Remove RID Lookup – Remove Key Lookup – Part 3 Interesting Observation – Query Hint – FORCE ORDER SQL Server never stops to amaze me. As regular readers of this blog already know that besides conducting corporate training, I work on large-scale projects on query optimizations and server tuning projects. In one of the recent projects, I have noticed that a Junior Database Developer used the query hint Force Order; when I asked for details, I found out that the basic concept was not properly understood by him. Queries Waiting for Memory Allocation to Execute In one of the recent projects, I was asked to create a report of queries that are waiting for memory allocation. The reason was that we were doubtful regarding whether the memory was sufficient for the application. The following query can be useful in similar cases. Queries that do not have to wait on a memory grant will not appear in the result set of following query. 2010 Quickest Way to Identify Blocking Query and Resolution – Dirty Solution As the title suggests, this is quite a dirty solution; it’s not as elegant as you expect. However, it works totally fine. Simple Explanation of Data Type Precedence While I was working on creating a question for SQL SERVER – SQL Quiz – The View, The Table and The Clustered Index Confusion, I had actually created yet another question along with this question. However, I felt that the one which is posted on the SQL Quiz is much better than this one because what makes that more challenging question is that it has a multiple answer. Encrypted Stored Procedure and Activity Monitor I recently had received questionable if any stored procedure is encrypted can we see its definition in Activity Monitor.Answer is - No. Let us do a quick test. Let us create following Stored Procedure and then launch the Activity Monitor and check the text. Indexed View always Use Index on Table A single table can have maximum 249 non clustered indexes and 1 clustered index. In SQL Server 2008, a single table can have maximum 999 non clustered indexes and 1 clustered index. It is widely believed that a table can have only 1 clustered index, and this belief is true. I have some questions for all of you. Let us assume that I am creating view from the table itself and then create a clustered index on it. In my view, I am selecting the complete table itself. 2011 Detecting Database Case Sensitive Property using fn_helpcollations() I received a question on how to determine the case sensitivity of the database. The quick answer to this is to identify the collation of the database and check the properties of the collation. I have previously written how one can identify database collation. Once you have figured out the collation of the database, you can put that in the WHERE condition of the following T-SQL and then check the case sensitivity from the description. Server Side Paging in SQL Server CE (Compact Edition) SQL Server Denali is coming up with new T-SQL of Paging. I have written about the same earlier.SQL SERVER – Server Side Paging in SQL Server Denali – A Better Alternative,  SQL SERVER – Server Side Paging in SQL Server Denali Performance Comparison, SQL SERVER – Server Side Paging in SQL Server Denali – Part2 What is very interesting is that SQL Server CE 4.0 have the same feature introduced. Here is the quick example of the same. To run the script in the example, you will have to do installWebmatrix 4.0 and download sample database. Once done you can run following script. Why I am Going to Attend PASS Summit Unite 2011 The four-day event will be marked by a lot of learning, sharing, and networking, which will help me increase both my knowledge and contacts. Every year, PASS Summit provides me a golden opportunity to build my network as well as to identify and meet potential customers or employees. 2012 Manage Help Settings – CTRL + ALT + F1 This is very interesting read as my daughter once accidently came across a screen in SQL Server Management Studio. It took me 2-3 minutes to figure out how she has created the same screen. Recover the Accidentally Renamed Table “I accidentally renamed table in my SSMS. I was scrolling very fast and I made mistakes. It was either because I double clicked or clicked on F2 (shortcut key for renaming). However, I have made the mistake and now I have no idea how to fix this. If you have renamed the table, I think you pretty much is out of luck. Here are few things which you can do which can give you an idea about what your table name can be if you are lucky. Identify Numbers of Non Clustered Index on Tables for Entire Database Here is the script which will give you numbers of non clustered indexes on any table in entire database. Identify Most Resource Intensive Queries – SQL in Sixty Seconds #029 – Video Here is the complete complete script which I have used in the SQL in Sixty Seconds Video. Thanks Harsh for important Tip in the comment. http://www.youtube.com/watch?v=3kDHC_Tjrns Advanced Data Quality Services with Melissa Data – Azure Data Market For the purposes of the review, I used a database I had in an Excel spreadsheet with name and address information. Upon a cursory inspection, there are miscellaneous problems with these records; some addresses are missing ZIP codes, others missing a city, and some records are slightly misspelled or have unparsed suites. With DQS, I can easily add a knowledge base to help standardize my values, such as for state abbreviations. But how do I know that my address is correct? Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Elegance, thy Name is jQuery

    - by SGWellens
    So, I'm browsing though some questions over on the Stack Overflow website and I found a good jQuery question just a few minutes old. Here is a link to it. It was a tough question; I knew that by answering it, I could learn new stuff and reinforce what I already knew: Reading is good, doing is better. Maybe I could help someone in the process too. I cut and pasted the HTML from the question into my Visual Studio IDE and went back to Stack Overflow to reread the question. Dang, someone had already answered it! And it was a great answer. I never even had a chance to start analyzing the issue. Now I know what a one-legged man feels like in an ass-kicking contest. Nevertheless, since the question and answer were so interesting, I decided to dissect them and learn as much as possible. The HTML consisted of some divs separated by h3 headings.  Note the elements are laid out sequentially with no programmatic grouping: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div></form></body>  The requirement was to wrap a div around each h3 heading and the subsequent divs grouping them into sections. Why? I don't know, I suppose if you screen-scrapped some HTML from another site, you might want to reformat it before displaying it on your own. Anyways… Here is the marvelously, succinct posted answer: $('.heading').each(function(){ $(this).nextUntil('.heading').andSelf().wrapAll('<div class="section">');}); I was familiar with all the parts except for nextUntil and andSelf. But, I'll analyze the whole answer for completeness. I'll do this by rewriting the posted answer in a different style and adding a boat-load of comments: function Test(){ // $Sections is a jQuery object and it will contain three elements var $Sections = $('.heading'); // use each to iterate over each of the three elements $Sections.each(function () { // $this is a jquery object containing the current element // being iterated var $this = $(this); // nextUntil gets the following sibling elements until it reaches // an element with the CSS class 'heading' // andSelf adds in the source element (this) to the collection $this = $this.nextUntil('.heading').andSelf(); // wrap the elements with a div $this.wrapAll('<div class="section" >'); });}  The code here doesn't look nearly as concise and elegant as the original answer. However, unless you and your staff are jQuery masters, during development it really helps to work through algorithms step by step. You can step through this code in the debugger and examine the jQuery objects to make sure one step is working before proceeding on to the next. It's much easier to debug and troubleshoot when each logical coding step is a separate line of code. Note: You may think the original code runs much faster than this version. However, the time difference is trivial: Not enough to worry about: Less than 1 millisecond (tested in IE and FF). Note: You may want to jam everything into one line because it results in less traffic being sent to the client. That is true. However, most Internet servers now compress HTML and JavaScript by stripping out comments and white space (go to Bing or Google and view the source). This feature should be enabled on your server: Let the server compress your code, you don't need to do it. Free Career Advice: Creating maintainable code is Job One—Maximum Priority—The Prime Directive. If you find yourself suddenly transferred to customer support, it may be that the code you are writing is not as readable as it could be and not as readable as it should be. Moving on… I created a CSS class to enhance the results: .section{ background-color: yellow; border: 2px solid black; margin: 5px;} Here is the rendered output before:   …and after the jQuery code runs.   Pretty Cool! But, while playing with this code, the logic of nextUntil began to bother me: What happens in the last section? What stops elements from being collected since there are no more elements with the .heading class? The answer is nothing.  In this case it stopped collecting elements because it was at the end of the page.  But what if there were additional HTML elements? I added an anchor tag and another div to the HTML: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div><a>this is a link</a><div>unrelated div</div> </form></body> The code as-is will include both the anchor and the unrelated div. This isn't what we want.   My first attempt to correct this used the filter parameter of the nextUntil function: nextUntil('.heading', 'div')  This will only collect div elements. But it merely skipped the anchor tag and it still collected the unrelated div:   The problem is we need a way to tell the nextUntil function when to stop. CSS selectors to the rescue! nextUntil('.heading, a')  This tells nextUntil to stop collecting elements when it gets to an element with a .heading class OR when it gets to an anchor tag. In this case it solved the problem. FYI: The comma operator in a CSS selector allows multiple criteria.   Bingo! One final note, we could have broken the code down even more: We could have replaced the andSelf function here: $this = $this.nextUntil('.heading, a').andSelf(); With this: // get all the following siblings and then add the current item$this = $this.nextUntil('.heading, a');$this.add(this);  But in this case, the andSelf function reads real nice. In my opinion. Here's a link to a jsFiddle if you want to play with it. I hope someone finds this useful Steve Wellens CodeProject

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  • The Great Divorce

    - by BlackRabbitCoder
    I have a confession to make: I've been in an abusive relationship for more than 17 years now.  Yes, I am not ashamed to admit it, but I'm finally doing something about it. I met her in college, she was new and sexy and amazingly fast -- and I'd never met anything like her before.  Her style and her power captivated me and I couldn't wait to learn more about her.  I took a chance on her, and though I learned a lot from her -- and will always be grateful for my time with her -- I think it's time to move on. Her name was C++, and she so outshone my previous love, C, that any thoughts of going back evaporated in the heat of this new romance.  She promised me she'd be gentle and not hurt me the way C did.  She promised me she'd clean-up after herself better than C did.  She promised me she'd be less enigmatic and easier to keep happy than C was.  But I was deceived.  Oh sure, as far as truth goes, it wasn't a complete lie.  To some extent she was more fun, more powerful, safer, and easier to maintain.  But it just wasn't good enough -- or at least it's not good enough now. I loved C++, some part of me still does, it's my first-love of programming languages and I recognize its raw power, its blazing speed, and its improvements over its predecessor.  But with today's hardware, at speeds we could only dream to conceive of twenty years ago, that need for speed -- at the cost of all else -- has died, and that has left my feelings for C++ moribund. If I ever need to write an operating system or a device driver, then I might need that speed.  But 99% of the time I don't.  I'm a business-type programmer and chances are 90% of you are too, and even the ones who need speed at all costs may be surprised by how much you sacrifice for that.   That's not to say that I don't want my software to perform, and it's not to say that in the business world we don't care about speed or that our job is somehow less difficult or technical.  There's many times we write programs to handle millions of real-time updates or handle thousands of financial transactions or tracking trading algorithms where every second counts.  But if I choose to write my code in C++ purely for speed chances are I'll never notice the speed increase -- and equally true chances are it will be far more prone to crash and far less easy to maintain.  Nearly without fail, it's the macro-optimizations you need, not the micro-optimizations.  If I choose to write a O(n2) algorithm when I could have used a O(n) algorithm -- that can kill me.  If I choose to go to the database to load a piece of unchanging data every time instead of caching it on first load -- that too can kill me.  And if I cross the network multiple times for pieces of data instead of getting it all at once -- yes that can also kill me.  But choosing an overly powerful and dangerous mid-level language to squeeze out every last drop of performance will realistically not make stock orders process any faster, and more likely than not open up the system to more risk of crashes and resource leaks. And that's when my love for C++ began to die.  When I noticed that I didn't need that speed anymore.  That that speed was really kind of a lie.  Sure, I can be super efficient and pack bits in a byte instead of using separate boolean values.  Sure, I can use an unsigned char instead of an int.  But in the grand scheme of things it doesn't matter as much as you think it does.  The key is maintainability, and that's where C++ failed me.  I like to tell the other developers I work with that there's two levels of correctness in coding: Is it immediately correct? Will it stay correct? That is, you can hack together any piece of code and make it correct to satisfy a task at hand, but if a new developer can't come in tomorrow and make a fairly significant change to it without jeopardizing that correctness, it won't stay correct. Some people laugh at me when I say I now prefer maintainability over speed.  But that is exactly the point.  If you focus solely on speed you tend to produce code that is much harder to maintain over the long hall, and that's a load of technical debt most shops can't afford to carry and end up completely scrapping code before it's time.  When good code is written well for maintainability, though, it can be correct both now and in the future. And you know the best part is?  My new love is nearly as fast as C++, and in some cases even faster -- and better than that, I know C# will treat me right.  Her creators have poured hundreds of thousands of hours of time into making her the sexy beast she is today.  They made her easy to understand and not an enigmatic mess.  They made her consistent and not moody and amorphous.  And they made her perform as fast as I care to go by optimizing her both at compile time and a run-time. Her code is so elegant and easy on the eyes that I'm not worried where she will run to or what she'll pull behind my back.  She is powerful enough to handle all my tasks, fast enough to execute them with blazing speed, maintainable enough so that I can rely on even fairly new peers to modify my work, and rich enough to allow me to satisfy any need.  C# doesn't ask me to clean up her messes!  She cleans up after herself and she tries to make my life easier for me by taking on most of those optimization tasks C++ asked me to take upon myself.  Now, there are many of you who would say that I am the cause of my own grief, that it was my fault C++ didn't behave because I didn't pay enough attention to her.  That I alone caused the pain she inflicted on me.  And to some extent, you have a point.  But she was so high maintenance, requiring me to know every twist and turn of her vast and unrestrained power that any wrong term or bout of forgetfulness was met with painful reminders that she wasn't going to watch my back when I made a mistake.  But C#, she loves me when I'm good, and she loves me when I'm bad, and together we make beautiful code that is both fast and safe. So that's why I'm leaving C++ behind.  She says she's changing for me, but I have no interest in what C++0x may bring.  Oh, I'll still keep in touch, and maybe I'll see her now and again when she brings her problems to my door and asks for some attention -- for I always have a soft spot for her, you see.  But she's out of my house now.  I have three kids and a dog and a cat, and all require me to clean up after them, why should I have to clean up after my programming language as well?

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  • Elegance, thy Name is jQuery

    - by SGWellens
    So, I'm browsing though some questions over on the Stack Overflow website and I found a good jQuery question just a few minutes old. Here is a link to it. It was a tough question; I knew that by answering it, I could learn new stuff and reinforce what I already knew: Reading is good, doing is better. Maybe I could help someone in the process too. I cut and pasted the HTML from the question into my Visual Studio IDE and went back to Stack Overflow to reread the question. Dang, someone had already answered it! And it was a great answer. I never even had a chance to start analyzing the issue. Now I know what a one-legged man feels like in an ass-kicking contest. Nevertheless, since the question and answer were so interesting, I decided to dissect them and learn as much as possible. The HTML consisted of some divs separated by h3 headings.  Note the elements are laid out sequentially with no programmatic grouping: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div></form></body>  The requirement was to wrap a div around each h3 heading and the subsequent divs grouping them into sections. Why? I don't know, I suppose if you screen-scrapped some HTML from another site, you might want to reformat it before displaying it on your own. Anyways… Here is the marvelously, succinct posted answer: $('.heading').each(function(){ $(this).nextUntil('.heading').andSelf().wrapAll('<div class="section">');}); I was familiar with all the parts except for nextUntil and andSelf. But, I'll analyze the whole answer for completeness. I'll do this by rewriting the posted answer in a different style and adding a boat-load of comments: function Test(){ // $Sections is a jQuery object and it will contain three elements var $Sections = $('.heading'); // use each to iterate over each of the three elements $Sections.each(function () { // $this is a jquery object containing the current element // being iterated var $this = $(this); // nextUntil gets the following sibling elements until it reaches // an element with the CSS class 'heading' // andSelf adds in the source element (this) to the collection $this = $this.nextUntil('.heading').andSelf(); // wrap the elements with a div $this.wrapAll('<div class="section" >'); });}  The code here doesn't look nearly as concise and elegant as the original answer. However, unless you and your staff are jQuery masters, during development it really helps to work through algorithms step by step. You can step through this code in the debugger and examine the jQuery objects to make sure one step is working before proceeding on to the next. It's much easier to debug and troubleshoot when each logical coding step is a separate line. Note: You may think the original code runs much faster than this version. However, the time difference is trivial: Not enough to worry about: Less than 1 millisecond (tested in IE and FF). Note: You may want to jam everything into one line because it results in less traffic being sent to the client. That is true. However, most Internet servers now compress HTML and JavaScript by stripping out comments and white space (go to Bing or Google and view the source). This feature should be enabled on your server: Let the server compress your code, you don't need to do it. Free Career Advice: Creating maintainable code is Job One—Maximum Priority—The Prime Directive. If you find yourself suddenly transferred to customer support, it may be that the code you are writing is not as readable as it could be and not as readable as it should be. Moving on… I created a CSS class to see the results: .section{ background-color: yellow; border: 2px solid black; margin: 5px;} Here is the rendered output before:   …and after the jQuery code runs.   Pretty Cool! But, while playing with this code, the logic of nextUntil began to bother me: What happens in the last section? What stops elements from being collected since there are no more elements with the .heading class? The answer is nothing.  In this case it stopped because it was at the end of the page.  But what if there were additional HTML elements? I added an anchor tag and another div to the HTML: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div><a>this is a link</a><div>unrelated div</div> </form></body> The code as-is will include both the anchor and the unrelated div. This isn't what we want.   My first attempt to correct this used the filter parameter of the nextUntil function: nextUntil('.heading', 'div')  This will only collect div elements. But it merely skipped the anchor tag and it still collected the unrelated div:   The problem is we need a way to tell the nextUntil function when to stop. CSS selectors to the rescue: nextUntil('.heading, a')  This tells nextUntil to stop collecting sibling elements when it gets to an element with a .heading class OR when it gets to an anchor tag. In this case it solved the problem. FYI: The comma operator in a CSS selector allows multiple criteria.   Bingo! One final note, we could have broken the code down even more: We could have replaced the andSelf function here: $this = $this.nextUntil('.heading, a').andSelf(); With this: // get all the following siblings and then add the current item$this = $this.nextUntil('.heading, a');$this.add(this);  But in this case, the andSelf function reads real nice. In my opinion. Here's a link to a jsFiddle if you want to play with it. I hope someone finds this useful Steve Wellens CodeProject

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  • How do I restrict concurrent statistics gathering to a small set of tables from a single schema?

    - by Maria Colgan
    I got an interesting question from one of my colleagues in the performance team last week about how to restrict a concurrent statistics gather to a small subset of tables from one schema, rather than the entire schema. I thought I would share the solution we came up with because it was rather elegant, and took advantage of concurrent statistics gathering, incremental statistics, and the not so well known “obj_filter_list” parameter in DBMS_STATS.GATHER_SCHEMA_STATS procedure. You should note that the solution outline below with “obj_filter_list” still applies, even when concurrent statistics gathering and/or incremental statistics gathering is disabled. The reason my colleague had asked the question in the first place was because he wanted to enable incremental statistics for 5 large partitioned tables in one schema. The first time you gather statistics after you enable incremental statistics on a table, you have to gather statistics for all of the existing partitions so that a synopsis may be created for them. If the partitioned table in question is large and contains a lot of partition, this could take a considerable amount of time. Since my colleague only had the Exadata environment at his disposal overnight, he wanted to re-gather statistics on 5 partition tables as quickly as possible to ensure that it all finished before morning. Prior to Oracle Database 11g Release 2, the only way to do this would have been to write a script with an individual DBMS_STATS.GATHER_TABLE_STATS command for each partition, in each of the 5 tables, as well as another one to gather global statistics on the table. Then, run each script in a separate session and manually manage how many of this session could run concurrently. Since each table has over one thousand partitions that would definitely be a daunting task and would most likely keep my colleague up all night! In Oracle Database 11g Release 2 we can take advantage of concurrent statistics gathering, which enables us to gather statistics on multiple tables in a schema (or database), and multiple (sub)partitions within a table concurrently. By using concurrent statistics gathering we no longer have to run individual statistics gathering commands for each partition. Oracle will automatically create a statistics gathering job for each partition, and one for the global statistics on each partitioned table. With the use of concurrent statistics, our script can now be simplified to just five DBMS_STATS.GATHER_TABLE_STATS commands, one for each table. This approach would work just fine but we really wanted to get this down to just one command. So how can we do that? You may be wondering why we didn’t just use the DBMS_STATS.GATHER_SCHEMA_STATS procedure with the OPTION parameter set to ‘GATHER STALE’. Unfortunately the statistics on the 5 partitioned tables were not stale and enabling incremental statistics does not mark the existing statistics stale. Plus how would we limit the schema statistics gather to just the 5 partitioned tables? So we went to ask one of the statistics developers if there was an alternative way. The developer told us the advantage of the “obj_filter_list” parameter in DBMS_STATS.GATHER_SCHEMA_STATS procedure. The “obj_filter_list” parameter allows you to specify a list of objects that you want to gather statistics on within a schema or database. The parameter takes a collection of type DBMS_STATS.OBJECTTAB. Each entry in the collection has 5 feilds; the schema name or the object owner, the object type (i.e., ‘TABLE’ or ‘INDEX’), object name, partition name, and subpartition name. You don't have to specify all five fields for each entry. Empty fields in an entry are treated as if it is a wildcard field (similar to ‘*’ character in LIKE predicates). Each entry corresponds to one set of filter conditions on the objects. If you have more than one entry, an object is qualified for statistics gathering as long as it satisfies the filter conditions in one entry. You first must create the collection of objects, and then gather statistics for the specified collection. It’s probably easier to explain this with an example. I’m using the SH sample schema but needed a couple of additional partitioned table tables to get recreate my colleagues scenario of 5 partitioned tables. So I created SALES2, SALES3, and COSTS2 as copies of the SALES and COSTS table respectively (setup.sql). I also deleted statistics on all of the tables in the SH schema beforehand to more easily demonstrate our approach. Step 0. Delete the statistics on the tables in the SH schema. Step 1. Enable concurrent statistics gathering. Remember, this has to be done at the global level. Step 2. Enable incremental statistics for the 5 partitioned tables. Step 3. Create the DBMS_STATS.OBJECTTAB and pass it to the DBMS_STATS.GATHER_SCHEMA_STATS command. Here, you will notice that we defined two variables of DBMS_STATS.OBJECTTAB type. The first, filter_lst, will be used to pass the list of tables we want to gather statistics on, and will be the value passed to the obj_filter_list parameter. The second, obj_lst, will be used to capture the list of tables that have had statistics gathered on them by this command, and will be the value passed to the objlist parameter. In Oracle Database 11g Release 2, you need to specify the objlist parameter in order to get the obj_filter_list parameter to work correctly due to bug 14539274. Will also needed to define the number of objects we would supply in the obj_filter_list. In our case we ere specifying 5 tables (filter_lst.extend(5)). Finally, we need to specify the owner name and object name for each of the objects in the list. Once the list definition is complete we can issue the DBMS_STATS.GATHER_SCHEMA_STATS command. Step 4. Confirm statistics were gathered on the 5 partitioned tables. Here are a couple of other things to keep in mind when specifying the entries for the  obj_filter_list parameter. If a field in the entry is empty, i.e., null, it means there is no condition on this field. In the above example , suppose you remove the statement Obj_filter_lst(1).ownname := ‘SH’; You will get the same result since when you have specified gather_schema_stats so there is no need to further specify ownname in the obj_filter_lst. All of the names in the entry are normalized, i.e., uppercased if they are not double quoted. So in the above example, it is OK to use Obj_filter_lst(1).objname := ‘sales’;. However if you have a table called ‘MyTab’ instead of ‘MYTAB’, then you need to specify Obj_filter_lst(1).objname := ‘”MyTab”’; As I said before, although we have illustrated the usage of the obj_filter_list parameter for partitioned tables, with concurrent and incremental statistics gathering turned on, the obj_filter_list parameter is generally applicable to any gather_database_stats, gather_dictionary_stats and gather_schema_stats command. You can get a copy of the script I used to generate this post here. +Maria Colgan

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  • elffile: ELF Specific File Identification Utility

    - by user9154181
    Solaris 11 has a new standard user level command, /usr/bin/elffile. elffile is a variant of the file utility that is focused exclusively on linker related files: ELF objects, archives, and runtime linker configuration files. All other files are simply identified as "non-ELF". The primary advantage of elffile over the existing file utility is in the area of archives — elffile examines the archive members and can produce a summary of the contents, or per-member details. The impetus to add elffile to Solaris came from the effort to extend the format of Solaris archives so that they could grow beyond their previous 32-bit file limits. That work introduced a new archive symbol table format. Now that there was more than one possible format, I thought it would be useful if the file utility could identify which format a given archive is using, leading me to extend the file utility: % cc -c ~/hello.c % ar r foo.a hello.o % file foo.a foo.a: current ar archive, 32-bit symbol table % ar r -S foo.a hello.o % file foo.a foo.a: current ar archive, 64-bit symbol table In turn, this caused me to think about all the things that I would like the file utility to be able to tell me about an archive. In particular, I'd like to be able to know what's inside without having to unpack it. The end result of that train of thought was elffile. Much of the discussion in this article is adapted from the PSARC case I filed for elffile in December 2010: PSARC 2010/432 elffile Why file Is No Good For Archives And Yet Should Not Be Fixed The standard /usr/bin/file utility is not very useful when applied to archives. When identifying an archive, a user typically wants to know 2 things: Is this an archive? Presupposing that the archive contains objects, which is by far the most common use for archives, what platform are the objects for? Are they for sparc or x86? 32 or 64-bit? Some confusing combination from varying platforms? The file utility provides a quick answer to question (1), as it identifies all archives as "current ar archive". It does nothing to answer the more interesting question (2). To answer that question, requires a multi-step process: Extract all archive members Use the file utility on the extracted files, examine the output for each file in turn, and compare the results to generate a suitable summary description. Remove the extracted files It should be easier and more efficient to answer such an obvious question. It would be reasonable to extend the file utility to examine archive contents in place and produce a description. However, there are several reasons why I decided not to do so: The correct design for this feature within the file utility would have file examine each archive member in turn, applying its full abilities to each member. This would be elegant, but also represents a rather dramatic redesign and re-implementation of file. Archives nearly always contain nothing but ELF objects for a single platform, so such generality in the file utility would be of little practical benefit. It is best to avoid adding new options to standard utilities for which other implementations of interest exist. In the case of the file utility, one concern is that we might add an option which later appears in the GNU version of file with a different and incompatible meaning. Indeed, there have been discussions about replacing the Solaris file with the GNU version in the past. This may or may not be desirable, and may or may not ever happen. Either way, I don't want to preclude it. Examining archive members is an O(n) operation, and can be relatively slow with large archives. The file utility is supposed to be a very fast operation. I decided that extending file in this way is overkill, and that an investment in the file utility for better archive support would not be worth the cost. A solution that is more narrowly focused on ELF and other linker related files is really all that we need. The necessary code for doing this already exists within libelf. All that is missing is a small user-level wrapper to make that functionality available at the command line. In that vein, I considered adding an option for this to the elfdump utility. I examined elfdump carefully, and even wrote a prototype implementation. The added code is small and simple, but the conceptual fit with the rest of elfdump is poor. The result complicates elfdump syntax and documentation, definite signs that this functionality does not belong there. And so, I added this functionality as a new user level command. The elffile Command The syntax for this new command is elffile [-s basic | detail | summary] filename... Please see the elffile(1) manpage for additional details. To demonstrate how output from elffile looks, I will use the following files: FileDescription configA runtime linker configuration file produced with crle dwarf.oAn ELF object /etc/passwdA text file mixed.aArchive containing a mixture of ELF and non-ELF members mixed_elf.aArchive containing ELF objects for different machines not_elf.aArchive containing no ELF objects same_elf.aArchive containing a collection of ELF objects for the same machine. This is the most common type of archive. The file utility identifies these files as follows: % file config dwarf.o /etc/passwd mixed.a mixed_elf.a not_elf.a same_elf.a config: Runtime Linking Configuration 64-bit MSB SPARCV9 dwarf.o: ELF 64-bit LSB relocatable AMD64 Version 1 /etc/passwd: ascii text mixed.a: current ar archive, 32-bit symbol table mixed_elf.a: current ar archive, 32-bit symbol table not_elf.a: current ar archive same_elf.a: current ar archive, 32-bit symbol table By default, elffile uses its "summary" output style. This output differs from the output from the file utility in 2 significant ways: Files that are not an ELF object, archive, or runtime linker configuration file are identified as "non-ELF", whereas the file utility attempts further identification for such files. When applied to an archive, the elffile output includes a description of the archive's contents, without requiring member extraction or other additional steps. Applying elffile to the above files: % elffile config dwarf.o /etc/passwd mixed.a mixed_elf.a not_elf.a same_elf.a config: Runtime Linking Configuration 64-bit MSB SPARCV9 dwarf.o: ELF 64-bit LSB relocatable AMD64 Version 1 /etc/passwd: non-ELF mixed.a: current ar archive, 32-bit symbol table, mixed ELF and non-ELF content mixed_elf.a: current ar archive, 32-bit symbol table, mixed ELF content not_elf.a: current ar archive, non-ELF content same_elf.a: current ar archive, 32-bit symbol table, ELF 64-bit LSB relocatable AMD64 Version 1 The output for same_elf.a is of particular interest: The vast majority of archives contain only ELF objects for a single platform, and in this case, the default output from elffile answers both of the questions about archives posed at the beginning of this discussion, in a single efficient step. This makes elffile considerably more useful than file, within the realm of linker-related files. elffile can produce output in two other styles, "basic", and "detail". The basic style produces output that is the same as that from 'file', for linker-related files. The detail style produces per-member identification of archive contents. This can be useful when the archive contents are not homogeneous ELF object, and more information is desired than the summary output provides: % elffile -s detail mixed.a mixed.a: current ar archive, 32-bit symbol table mixed.a(dwarf.o): ELF 32-bit LSB relocatable 80386 Version 1 mixed.a(main.c): non-ELF content mixed.a(main.o): ELF 64-bit LSB relocatable AMD64 Version 1 [SSE]

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  • “It’s only test code…”

    - by Chris George
    “Let me hack this in, it’s only test code”, “Don’t worry about getting it reviewed, it’s only test code”, “It doesn’t have to be elegant or efficient, it’s only test code”… do these phrases sound familiar? Chances are if you’ve working with test automation, at one point or other you will have heard these phrases, you have probably even used them yourself! What is certain is that code written under this “it’s only test code” mantra will come back and bite you in the arse! I’ve recently encountered a case where a test was giving a false positive, therefore hiding a real product bug because that test code was very badly written. Firstly it was very difficult to understand what the test was actually trying to achieve let alone how it was doing it, and this complexity masked a simple logic error. These issues are real and they do happen. Let’s take a step back from this and look at what we are trying to do. We are writing test code that tests product code, and we do this to create a suite of tests that will help protect our software against regressions. This test code is making sure that the product behaves as it should by employing some sort of expected result verification. The simple cases of these are generally not a problem. However, automation allows us to explore more complex scenarios in many more permutations. As this complexity increases then so does the complexity of the test code. It is at this point that code which has not been architected properly will cause problems.   Keep your friends close… So, how do we make sure we are doing it right? The development teams I have worked on have always had Test Engineers working very closely with their Software Engineers. This is something that I have always tried to take full advantage of. They are coding experts! So run your ideas past them, ask for advice on how to structure your code, help you design your data structures. This may require a shift in your teams viewpoint, as contrary to this section title and folklore, Software Engineers are not actually the mortal enemy of Test Engineers. As time progresses, and test automation becomes more and more ingrained in what we do, the two roles are converging more than ever. Over the 16 years I have spent as a Test Engineer, I have seen the grey area between the two roles grow significantly larger. This serves to strengthen the relationship and common bond between the two roles which helps to make test code activities so much easier!   Pair for the win Possibly the best thing you could do to write good test code is to pair program on the task. This will serve a few purposes. you will get the benefit of the Software Engineers knowledge and experience the Software Engineer will gain knowledge on the testing process. Sharing the love is a wonderful thing! two pairs of eyes are always better than one… And so are two brains. Between the two of you, I will guarantee you will derive more useful test cases than if it was just one of you.   Code reviews Another policy which certainly pays dividends is the practice of code reviews. By having one of your peers review your code before you commit it serves two purposes. Firstly, it forces you to explain your code. Just the act of doing this will often pick up errors in your code. Secondly, it gets yet another pair of eyes on your code! I cannot stress enough how important code reviews are. The benefits they offer apply as much to product code as test code. In short, Software and Test Engineers should all be doing them! It can be extended even further by getting test code reviewed by a Software Engineer and a Test Engineer, and likewise product code. This serves to keep both functions in the loop with changes going on within your code base.   Learn from your devs I briefly touched on this earlier but I’d like to go into more detail here. Pairing with your Software Engineers when writing your test code is such an amazing opportunity to improve your coding skills. As I sit here writing this article waiting to be called into court for jury service, it reminds me that it takes a lot of patience to be a Test Engineer, almost as much as it takes to be a juror! However tempting it is to go rushing in and start writing your automated tests, resist that urge. Discuss what you want to achieve then talk through the approach you’re going to take. Then code it up together. I find it really enlightening to ask questions like ‘is there a better way to do this?’ Or ‘is this how you would code it?’ The latter question, especially, is where I learn the most. I’ve found that most Software Engineers will be reluctant to show you the ‘right way’ to code something when writing tests because they perceive the ‘right way’ to be too complicated for the Test Engineer (e.g. not mentioning LINQ and instead doing something verbose). So by asking how THEY would code it, it unleashes their true dev-ness and advanced code usually ensues! I would like to point out, however, that you don’t have to accept their method as the final answer. On numerous occasions I have opted for the more simple/verbose solution because I found the code written by the Software Engineer too advanced and therefore I would find it unreadable when I return to the code in a months’ time! Always keep the target audience in mind when writing clever code, and in my case that is mostly Test Engineers.  

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  • Understanding Windows 8 Recovery options

    - by stuffe
    Background: I am preparing a PC that I am sending to a relative abroad, who has little or no internet access, and next to no sensible options for getting IT support should anything go wrong. As such I am trying to provide a full set of recovery options such that they are able to reinstall the OS with minimum fuss or assistance if required. The PC is a brand new Acer laptop that came with Windows 7 pre-installed (and an associated recovery partition) and a free upgrade to Windows 8. I have installed Windows 8 from scratch performing a format and clean install from media I burned from the official download. The existing Windows 7 recovery partition is still there, and I can still boot from it. I have created recovery DVDs of that in case it is ever lost. Here are my recovery options so far. I can perform a factory reset of Win 7 via the recovery partition I can perform a factory reset of Win 7 via burned recovery DVDs I can re-install Windows 8 cleanly from a DVD All of these are useful, but not what I want, because the first 2 methods use Win 7, and still fill the machine with crapware, and the latter doesn't provide for any post-install customisation and software installation. So, I am looking to see what other options are available to perform a Windows 8 recovery that will be more than a simple install. I am aware that Win8 comes with some useful refresh tools: Refresh your PC - Re-install Win 8 over the top of your existing installation, recovering from any Windows corruption etc. I can run this from my current install, although it says some files are missing that will be provided by me install or recovery media, which seems to be code for stick your install DVD in, and it starts after I do that - unfortunately for this particular laptop you need to specify a particular WIFI driver or the install bombs out part way through with IRQL errors, and this refresh method skips the part where you can load a driver, so it's no use to me. I think I can fix this by creating a custom recovery image using the recimg.exe command but it takes hours to complete so I haven't tried it yet. Reset your PC - Perform a full install and lose all your files. Again it needs my Install media inserting before it will do anything, but then it provides an error (will include later when I recreate it...) Now, these recovery options look useful (in principal, although both are fail for me) but they rely on having a working system to access the tools, which leads me to the last option, of making a Recovery USB drive. I have made a recovery drive, and it should perform loads of useful things, including copying my WIN7 recovery partition to the drive, providing the above refresh and reset options, providing other troubleshooting options and also the ability to restore from a custom image, only none of them seem to work for me. Creating the Recovery Drive - the option to include my recovery partition is greyed out. The partition exists and works fine, why will it not copy it? Refresh - I imagine this would have the same issues as I described before, but this is moot because when I try it says that the "drive where Windows is installed is locked, please unlock the drive and try again" with no info on what that means and how to do it. Restore - Again, probably pointless as I can just use the DVD, but it also errors: "unable to reset your PC. A required drive partition is missing" System Restore - should let me roll back a bad driver etc as per normal in Windows, only it simply says "To use system restore you must specify which windows installation to restore. Restart this computer, select an operating system, and select system restore" ?!?! System Image Recovery - this seems to be offering to restore from a Windows system image, but this is deprecated in Windows 8, although you can still make one if you use the Windows 7 Backup tools, however the resultant file is too large to put on the USB stick as it's FAT formatted, and would be a massive stack of DVDs anyway. So useless. It would be nice it it would work with the custom recovery image you can use with the refresh command, but there seems no option to do this. Automatic Repair - some diagnostics, which seem useless as it happily tells me it can't fix my problem, even though I have none. Command Prompt - yay, this works! What on earth do I want to use it for... Had any of the above worked, it might be useful, but as any form of install still requires you to have the DVD, and any form of custom recovery image also requires you to have either a massive stack of DVDs or an NTFS formatted backup device in addition to the recovery drive, it sort of ruins the point. It doesn't seem rocket science. I want to create a bootable USB drive that I can refresh Windows over an existing install with, perform a clean reinstall to a bare system, or recovery a customised image with existing apps installed. If anyone can point me in a direction that allows me to make a single recovery drive do these all these things, I would appreciate it. I have a 32Gb USB3 thumb drive that I bought for this very purpose, but it's seems to be fighting to let me do anything useful. At this rate I will be making a DriveImageXML recovery stick and dumping the OS with that, which I know works, but isn't so elegant as using the proper tools..

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  • Weighted round robins via TTL - possible?

    - by Joe Hopfgartner
    I currently use DNS round robin for load balancing, which works great. The records look like this (I have a ttl of 120 seconds) ;; ANSWER SECTION: orion.2x.to. 116 IN A 80.237.201.41 orion.2x.to. 116 IN A 87.230.54.12 orion.2x.to. 116 IN A 87.230.100.10 orion.2x.to. 116 IN A 87.230.51.65 I learned that not every ISP / device treats such a response the same way. For example some DNS servers rotate the addresses randomly or always cycle them through. Some just propagate the first entry, others try to determine which is best (regionally near) by looking at the ip address. However if the userbase is big enough (spreads over multiple ISPs etc) it balances pretty well. The discrepancies from highest to lowest loaded server hardly every exceeds 15%. However now I have the problem that I am introducing more servers into the systems, that not all have the same capacities. I currently only have 1gbps servers, but I want to work with 100mbit and also 10gbps servers too. So what I want is I want to introduce a server with 10 GBps with a weight of 100, a 1 gbps server with a weight of 10 and a 100 mbit server with a weight of 1. I used to add servers twice to bring more traffic to them (which worked nice. the bandwidth doubled almost.) But adding a 10gbit server 100 times to DNS is a bit rediculous. So I thought about using the TTL. If I give server A 240 seconds ttl and server B only 120 seconds (which is about about the minimum to use for round robin, as a lot of dns servers set to 120 if a lower ttl is specified.. so i have heard) I think something like this should occour in an ideal scenario: first 120 seconds 50% of requests get server A -> keep it for 240 seconds. 50% of requests get server B -> keep it for 120 seconds second 120 seconds 50% of requests still have server A cached -> keep it for another 120 seconds. 25% of requests get server A -> keep it for 240 seconds 25% of requests get server B -> keep it for 120 seconds third 120 seconds 25% will get server A (from the 50% of Server A that now expired) -> cache 240 sec 25% will get server B (from the 50% of Server A that now expired) -> cache 120 sec 25% will have server A cached for another 120 seconds 12.5% will get server B (from the 25% of server B that now expired) -> cache 120sec 12.5% will get server A (from the 25% of server B that now expired) -> cache 240 sec fourth 120 seconds 25% will have server A cached -> cache for another 120 secs 12.5% will get server A (from the 25% of b that now expired) -> cache 240 secs 12.5% will get server B (from the 25% of b that now expired) -> cache 120 secs 12.5% will get server A (from the 25% of a that now expired) -> cache 240 secs 12.5% will get server B (from the 25% of a that now expired) -> cache 120 secs 6.25% will get server A (from the 12.5% of b that now expired) -> cache 240 secs 6.25% will get server B (from the 12.5% of b that now expired) -> cache 120 secs 12.5% will have server A cached -> cache another 120 secs ... i think i lost something at this point but i think you get the idea.... As you can see this gets pretty complicated to predict and it will for sure not work out like this in practice. But it should definitely have an effect on the distribution! I know that weighted round robin exists and is just controlled by the root server. It just cycles through dns records when responding and returns dns records with a set propability that corresponds to the weighting. My DNS server does not support this, and my requirements are not that precise. If it doesnt weight perfectly its okay, but it should go into the right direction. I think using the TTL field could be a more elegant and easier solution - and it deosnt require a dns server that controls this dynamically, which saves resources - which is in my opinion the whole point of dns load balancing vs hardware load balancers. My question now is... are there any best prectices / methos / rules of thumb to weight round robin distribution using the TTL attribute of DNS records? Edit: The system is a forward proxy server system. The amount of Bandwidth (not requests) exceeds what one single server with ethernet can handle. So I need a balancing solution that distributes the bandwidth to several servers. Are there any alternative methods than using DNS? Of course I can use a load balancer with fibre channel etc, but the costs are rediciulous and it also increases only the width of the bottleneck and does not eliminate it. The only thing i can think of are anycast (is it anycast or multicast?) ip addresses, but I don't have the means to set up such a system.

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  • WPF TabControl - how to preserve control state within tab items (MVVM pattern)

    - by Tim Coulter
    I am a newcomer to WPF, attempting to build a project that follows the recommendations of Josh Smith's excellent article describing The Model-View-ViewModel Design Pattern. Using Josh's sample code as a base, I have created a simple application that contains a number of "workspaces", each represented by a tab in a TabControl. In my application, a workspace is a document editor that allows a hierarchical document to be manipulated via a TreeView control. Although I have succeeded in opening multiple workspaces and viewing their document content in the bound TreeView control, I find that the TreeView "forgets" its state when switching between tabs. For example, if the TreeView in Tab1 is partially expanded, it will be shown as fully collapsed after switching to Tab2 and returning to Tab1. This behaviour appears to apply to all aspects of control state for all controls. After some experimentation, I have realized that I can preserve state within a TabItem by explicitly binding each control state property to a dedicated property on the underlying ViewModel. However, this seems like a lot of additional work, when I simply want all my controls to remember their state when switching between workspaces. I assume I am missing something simple, but I am not sure where to look for the answer. Any guidance would be much appreciated. Thanks, Tim Update: As requested, I will attempt to post some code that demonstrates this problem. However, since the data that underlies the TreeView is complex, I will post a simplified example that exhibits the same symtoms. Here is the XAML from the main window: <TabControl IsSynchronizedWithCurrentItem="True" ItemsSource="{Binding Path=Docs}"> <TabControl.ItemTemplate> <DataTemplate> <ContentPresenter Content="{Binding Path=Name}" /> </DataTemplate> </TabControl.ItemTemplate> <TabControl.ContentTemplate> <DataTemplate> <view:DocumentView /> </DataTemplate> </TabControl.ContentTemplate> </TabControl> The above XAML correctly binds to an ObservableCollection of DocumentViewModel, whereby each member is presented via a DocumentView. For the simplicity of this example, I have removed the TreeView (mentioned above) from the DocumentView and replaced it with a TabControl containing 3 fixed tabs: <TabControl> <TabItem Header="A" /> <TabItem Header="B" /> <TabItem Header="C" /> </TabControl> In this scenario, there is no binding between the DocumentView and the DocumentViewModel. When the code is run, the inner TabControl is unable to remember its selection when the outer TabControl is switched. However, if I explicitly bind the inner TabControl's SelectedIndex property ... <TabControl SelectedIndex="{Binding Path=SelectedDocumentIndex}"> <TabItem Header="A" /> <TabItem Header="B" /> <TabItem Header="C" /> </TabControl> ... to a corresponding dummy property on the DocumentViewModel ... public int SelecteDocumentIndex { get; set; } ... the inner tab is able to remember its selection. I understand that I can effectively solve my problem by applying this technique to every visual property of every control, but I am hoping there is a more elegant solution.

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  • 14+ Real Estate WordPress Themes

    - by Aditi
    If you are looking for a great WordPress real estate theme. Below is a list of some of the best wordpress real estate themes, so you can find one, which is the best suited for you and be at par with increasing industry demands in real estates business.We have covered only the best themes available. The Themes are flexible & can be used by anybody in real estate business. If you are realtor, agent, appraiser or realty these can be modified as per your use. Estate It is an immensely powerful and simple to manage business theme. It offers advanced SEO control, clean code and styling modification features. It has new “Properties” management facility when installed – proving it’s far more than just a WordPress theme. It offers flexible page templates, an advanced search facility that allows you to drill down into properties based on very specific criteria, Google Maps integration and smart property images management. It is a complete web solution. It also has IDX functionality due to dsIDXpress plugin integration, which allows multi-listing services. Price: $200 View Demo Download ElegantEstate It makes your WordPress blog into a full-feature real estate website. The theme makes browsing your listings easy, and adds special integration features for property info, photos, Google Maps and more. Help increase sales by establishing an elegant and professional online presence today. It has opera compatibility, Netscape compatibility, Safari compatibility, WordPress 3.0 compatibility. It comes with five color schemes, threaded comments, optional blog-style structure, Gravatar ready, firefox compatible, IE8 + IE7 + IE6 compatible, advertisement ready, widget ready sidebars, theme options page, custom thumbnail images, PSD files, valid XHTML + CSS, smooth table less design, ePanel theme options, page templates, complete localization and many more features. Price: $39 (Package includes more than 55 themes) View Demo Download Open House Open House is fully compatible with WordPress 3.0+ and a highly customizable Real Estate WordPress theme. It has Google Maps Integration with Street View. It has a professional look for Agents and Realtors both. It is best suited for all markets and countries with theme localization, translation and internationalization. It provides for English, Spanish and Portuguese language files in the Developer Package. It has custom scripts, which makes it easy to add/delete/modify listings. It also includes photo gallery with a lightbox effect, gorgeous photo fade animations and automatic Google Maps integration. The theme can be used as a single or multi-agent website with individual Agent-Realtor pages with listings and biography information, Agent photo uploader, financing calculator.There is Multi Category search for potential customers to locate the house they want. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Residence Real Estate It is a WordPress 3.0+ compatible stunning real estate theme. It has a dynamic real estate framework management module for easy edit-delete-add more features options, which makes this theme super easy to customize to the market needs. It allows you to add your own labels and values in your own language and switch the theme to your own language with English and Spanish files included with the ability to add your own language. It offers Multi-Category search with breadcrumb filtered results, easy photo gallery management with drag-drop sorting of images. It allows you to build your own multi-category search section menu with custom labels-choices and unlimited dropdown menus. They have been presented in a professional module with search results in breadcrumb navigation. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Smooth Smooth is a WordPress Real Estate theme. It is a complete theme, which comes with Multi Category Search, Google Maps Integration, Agent Photo and Logo uploader that offers a professional and extremely affordable solution for Realtors and Agents to showcase their properties with ease. You can add your listings with the extremely easy and flexible Dynamic Real Estate Framework, edit-add-modify-delete all features, labels and values within the WordPress administration and upload unlimited photos to your galleries with latest WordPress 3.0+ features. It is a complete solution for real estate sites. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Homeowners It is another WordPress Real Estate theme, which is a fast loading optimized theme with Google Maps Integration, fully compatible with WordPress 3.0 features and all Real Estate markets. It has a professional clean look and it is full of features extremely easy to modify. It also provides for 12 new styles provided. English, Spanish and Portuguese language files are provided in the Developer Package. Homeowners WordPress Real Estate features custom scripts that make add/delete/modify listings an easy task with an included photo gallery with a lightbox effect and automatic Google Map integration with street view (New) Agents will have access only to their own listings and add the listing management for their account making this theme an ideal affordable solution for Realtors and Real Estate agencies. The theme can be used as a single or multi-agent website with individual Agent-Realtor pages with listings and biography information, Agent photo uploader, financing calculator. Multi category search has also been provided. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Real Agent Real Estate This theme is a WordPress 3.0+ compatible clean grid based real estate theme. It has a dynamic real estate framework management module for easy edit-delete-add more features options. It is easy to customize according to market. It allows you to add your own labels and values in your own language switch the theme to your own language with English and Spanish files included with the ability to add your own language. Multi-Category search with breadcrumb filtered results, easy photo gallery management with drag-drop sorting of images. You can upload property photos in bulk with the native WordPress uploader and the new image editing and resizing options in WordPress 3.0+. The theme features 5 different color styles, blue, black, red, green and purple with professional layouts, logo and agent photo uploaders. This theme is best suited for individual or multiple agents both. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Agent Press The AgentPress theme is an ideal solution for real estate agents. It offers multiple page templates that can be used to create a complete real estate website. You can create from single property templates to a custom homepage easily with it. It is compatible to WordPress 3.0 and 3.1. It has custom background/header, property template, 6 layout options, fixed width, threaded comments and many more features. Price: $99.95 View Demo Download Real Estate It is one of the best Real Estate themes. It offers single click auto install of the site, Allow user to pay & submit properties on your site, Multi-agent site with profiles, Strategically built real estate site with professional design, User dashboard to edit/renew their submissions, Auto generated Google Maps and Image Slideshows and many more unique features. Once the users search property as per their criteria, the properties are listed with all the necessary parameters that let them select the property of their choice. Users can also add the property to favorite so they can check the property later from their member area dashboard. Admin may display different sidebar on this page and add widgets of their choice. This theme is full of custom, dynamic widgets such as top agents, finance calculator, user login; advertise blocks, testimonials and so on. There is a property details page where users can see the actual property. The agent details is displayed with the full contact details and appropriate links so the visitor can get all info about the property being sold, seller and may contact them by filling out a simple form. The email will be sent directly to the person who listed the property. Price: $89.95 Single | $159.95 Developer View Demo Download Broker Real Estate It is also a WordPress 3.0+ compatible real estate theme. It has a featured property slideshow, dynamic real estate framework management module for easy edit-delete-add more features. You can add your own labels and values in your own language. It offers multi-category search with breadcrumb-filtered results, easy photo gallery management with drag-drop sorting of images. You can also build your own multi-category search section menu with custom labels-choices and unlimited dropdown menus. Price: $39.95 essential | $69.95 standard | $99.95 premium View Demo Download Decasa It has custom search panel that lets your user easily browse your properties by keyword search or category select drop downs. It offers the property exposé, which is a user-friendly overview over the most important details of each real estate object. You can easily add this data through a post settings meta box on the post edit screen. You can easily create a real estate image gallery. Its theme options panel makes it easy to make the basic theme settings. It supports the new WordPress post thumbnail feature. When uploading an image file the theme will automatically create all the necessary image size. You can also create your own custom menu easily and fast with drag and drop without touching any code. Price: 39 € View Demo Download RealtorPress A real estate premium WordPress theme from PremiumPress. Versatile WordPress Theme that can be used by individual agents or real estate companies. The theme allows you to easily add property listings via the custom backend admin area or import CSV spreadsheets. It features customisable search options, Google maps integration, real estate data custom field creator, image management tools and more. Price: $79 | Premium Collection: $259 (all PremiumPress themes) View Demo Download Related posts:21+ WordPress Photo Blog & Portfolio Themes 14+ WordPress Portfolio Themes Professional WordPress Business Themes

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  • WPF ContextMenu with bound items: Items.Count == 0 in ContextMenuOpening event

    - by OregonGhost
    I have a ContextMenu with the ItemsSource bound to the selected item of a list view, like this: <ContextMenu ItemsSource="{Binding Path=PlacementTarget.SelectedItem, RelativeSource={RelativeSource Self}, Converter={StaticResource possibleConverter}}"/> The possibleConverter enumerates all possible values for a property of the the selected item, which are shown in the context menu. In the Opened event of the context menu, I select the current value like this: var cm = e.OriginalSource as ContextMenu; if (cm != null) { var lv = cm.PlacementTarget as ListView; var field = lv.SelectedItem as Field; var item = cm.ItemContainerGenerator.ContainerFromItem(cm.Items.OfType<object>().Where(o => o.ToString().Equals(field.StringValue)).FirstOrDefault()) as MenuItem; if (item != null) { item.IsChecked = true; } } Not particularly elegant, but it works. With the debugger I verified that the ContextMenu.Items.Count property has a non-zero value when expected (i.e. cm.Items.Count is non-zero in the if). So far, so good. There are, however, items in the listview where the context menu will have no items. In this case, an empty menu is shown. I tried to suppress this in the ContextMenuOpening event in the list view, like this: var lv = sender as ListView; if (lv != null) { var cm = lv.ContextMenu; if ((cm != null) && (cm.Items.Count > 0)) { // Here we want to check the current item, which is currently done in the Opened event. } else { e.Handled = true; } } Seems like it should work. However, cm.Items.Count is always zero. This is true even if ListView.SelectedItem did not change: For an item with menu entries, the menu is shown correctly after the first click, so the data binding has already happend. It is shown correct the second time as well, but in any case, Items.Count is zero in the ContextMenuOpening event. What am I missing? How can I suppress empty context menus? Why is the count zero in the ContextMenuOpening handler, which is in Windows Forms (ContextMenuStrip.Opening) the canonical point where to do these things? EDIT: Upon further investigating, it turns out that in the ContextMenuOpening handler, any binding to the listview fails, which is why ItemsSource is null. I tried to bind via ElementName, via a FindAncestor relationship, all to no avail. The PlacementTarget is null during that event. An ugly hack worked though: In the ContextMenuOpening event, I assign the list view to the ContextMenu.Tag property, while the ItemsSource binding now binds to Tag.SelectedItem. This updates the binding, so Items.Count is what it should be. It's still strange. How can you do meaningful things in ContextMenuOpening other than replacing the menu or something, if the binding fails because somehow the context menu is out of context during the event? Was it only tested with static pre-defined menu items?

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  • Marrying Core Animation with OpenGL ES

    - by Ole Begemann
    Edit: I suppose instead of the long explanation below I might also ask: Sending -setNeedsDisplay to an instance of CAEAGLLayer does not cause the layer to redraw (i.e., -drawInContext: is not called). Instead, I get this console message: <GLLayer: 0x4d500b0>: calling -display has no effect. Is there a way around this issue? Can I invoke -drawInContext: when -setNeedsDisplay is called? Long explanation below: I have an OpenGL scene that I would like to animate using Core Animation animations. Following the standard approach to animate custom properties in a CALayer, I created a subclass of CAEAGLLayer and defined a property sceneCenterPoint in it whose value should be animated. My layer also holds a reference to the OpenGL renderer: #import <UIKit/UIKit.h> #import <QuartzCore/QuartzCore.h> #import "ES2Renderer.h" @interface GLLayer : CAEAGLLayer { ES2Renderer *renderer; } @property (nonatomic, retain) ES2Renderer *renderer; @property (nonatomic, assign) CGPoint sceneCenterPoint; I then declare the property @dynamic to let CA create the accessors, override +needsDisplayForKey: and implement -drawInContext: to pass the current value of the sceneCenterPoint property to the renderer and ask it to render the scene: #import "GLLayer.h" @implementation GLLayer @synthesize renderer; @dynamic sceneCenterPoint; + (BOOL) needsDisplayForKey:(NSString *)key { if ([key isEqualToString:@"sceneCenterPoint"]) { return YES; } else { return [super needsDisplayForKey:key]; } } - (void) drawInContext:(CGContextRef)ctx { self.renderer.centerPoint = self.sceneCenterPoint; [self.renderer render]; } ... (If you have access to the WWDC 2009 session videos, you can review this technique in session 303 ("Animated Drawing")). Now, when I create an explicit animation for the layer on the keyPath @"sceneCenterPoint", Core Animation should calculate the interpolated values for the custom properties and call -drawInContext: for each step of the animation: - (IBAction)animateButtonTapped:(id)sender { CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"sceneCenterPoint"]; animation.duration = 1.0; animation.fromValue = [NSValue valueWithCGPoint:CGPointZero]; animation.toValue = [NSValue valueWithCGPoint:CGPointMake(1.0f, 1.0f)]; [self.glView.layer addAnimation:animation forKey:nil]; } At least that is what would happen for a normal CALayer subclass. When I subclass CAEAGLLayer, I get this output on the console for each step of the animation: 2010-12-21 13:59:22.180 CoreAnimationOpenGL[7496:207] <GLLayer: 0x4e0be20>: calling -display has no effect. 2010-12-21 13:59:22.198 CoreAnimationOpenGL[7496:207] <GLLayer: 0x4e0be20>: calling -display has no effect. 2010-12-21 13:59:22.216 CoreAnimationOpenGL[7496:207] <GLLayer: 0x4e0be20>: calling -display has no effect. 2010-12-21 13:59:22.233 CoreAnimationOpenGL[7496:207] <GLLayer: 0x4e0be20>: calling -display has no effect. ... So it seems that, possibly for performance reasons, for OpenGL layers, -drawInContext: is not getting called because these layers do not use the standard -display method to draw themselves. Can anybody confirm that? Is there a way around it? Or can I not use the technique I laid out above? This would mean I would have to implement the animations manually in the OpenGL renderer (which is possible but not as elegant IMO).

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  • overriding ctype<wchar_t>

    - by Potatoswatter
    I'm writing a lambda calculus interpreter for fun and practice. I got iostreams to properly tokenize identifiers by adding a ctype facet which defines punctuation as whitespace: struct token_ctype : ctype<char> { mask t[ table_size ]; token_ctype() : ctype<char>( t ) { for ( size_t tx = 0; tx < table_size; ++ tx ) { t[tx] = isalnum( tx )? alnum : space; } } }; (classic_table() would probably be cleaner but that doesn't work on OS X!) And then swap the facet in when I hit an identifier: locale token_loc( in.getloc(), new token_ctype ); … locale const &oldloc = in.imbue( token_loc ); in.unget() >> token; in.imbue( oldloc ); There seems to be surprisingly little lambda calculus code on the Web. Most of what I've found so far is full of unicode ? characters. So I thought to try adding Unicode support. But ctype<wchar_t> works completely differently from ctype<char>. There is no master table; there are four methods do_is x2, do_scan_is, and do_scan_not. So I did this: struct token_ctype : ctype< wchar_t > { typedef ctype<wchar_t> base; bool do_is( mask m, char_type c ) const { return base::do_is(m,c) || (m&space) && ( base::do_is(punct,c) || c == L'?' ); } const char_type* do_is (const char_type* lo, const char_type* hi, mask* vec) const { base::do_is(lo,hi,vec); for ( mask *vp = vec; lo != hi; ++ vp, ++ lo ) { if ( *vp & punct || *lo == L'?' ) *vp |= space; } return hi; } const char_type *do_scan_is (mask m, const char_type* lo, const char_type* hi) const { if ( m & space ) m |= punct; hi = do_scan_is(m,lo,hi); if ( m & space ) hi = find( lo, hi, L'?' ); return hi; } const char_type *do_scan_not (mask m, const char_type* lo, const char_type* hi) const { if ( m & space ) { m |= punct; while ( * ( lo = base::do_scan_not(m,lo,hi) ) == L'?' && lo != hi ) ++ lo; return lo; } return base::do_scan_not(m,lo,hi); } }; (Apologies for the flat formatting; the preview converted the tabs differently.) The code is WAY less elegant. I does better express the notion that only punctuation is additional whitespace, but that would've been fine in the original had I had classic_table. Is there a simpler way to do this? Do I really need all those overloads? (Testing showed do_scan_not is extraneous here, but I'm thinking more broadly.) Am I abusing facets in the first place? Is the above even correct? Would it be better style to implement less logic?

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  • C#: Adding Functionality to 3rd Party Libraries With Extension Methods

    - by James Michael Hare
    Ever have one of those third party libraries that you love but it's missing that one feature or one piece of syntactical candy that would make it so much more useful?  This, I truly think, is one of the best uses of extension methods.  I began discussing extension methods in my last post (which you find here) where I expounded upon what I thought were some rules of thumb for using extension methods correctly.  As long as you keep in line with those (or similar) rules, they can often be useful for adding that little extra functionality or syntactical simplification for a library that you have little or no control over. Oh sure, you could take an open source project, download the source and add the methods you want, but then every time the library is updated you have to re-add your changes, which can be cumbersome and error prone.  And yes, you could possibly extend a class in a third party library and override features, but that's only if the class is not sealed, static, or constructed via factories. This is the perfect place to use an extension method!  And the best part is, you and your development team don't need to change anything!  Simply add the using for the namespace the extensions are in! So let's consider this example.  I love log4net!  Of all the logging libraries I've played with, it, to me, is one of the most flexible and configurable logging libraries and it performs great.  But this isn't about log4net, well, not directly.  So why would I want to add functionality?  Well, it's missing one thing I really want in the ILog interface: ability to specify logging level at runtime. For example, let's say I declare my ILog instance like so:     using log4net;     public class LoggingTest     {         private static readonly ILog _log = LogManager.GetLogger(typeof(LoggingTest));         ...     }     If you don't know log4net, the details aren't important, just to show that the field _log is the logger I have gotten from log4net. So now that I have that, I can log to it like so:     _log.Debug("This is the lowest level of logging and just for debugging output.");     _log.Info("This is an informational message.  Usual normal operation events.");     _log.Warn("This is a warning, something suspect but not necessarily wrong.");     _log.Error("This is an error, some sort of processing problem has happened.");     _log.Fatal("Fatals usually indicate the program is dying hideously."); And there's many flavors of each of these to log using string formatting, to log exceptions, etc.  But one thing there isn't: the ability to easily choose the logging level at runtime.  Notice, the logging levels above are chosen at compile time.  Of course, you could do some fun stuff with lambdas and wrap it, but that would obscure the simplicity of the interface.  And yes there is a Logger property you can dive down into where you can specify a Level, but the Level properties don't really match the ILog interface exactly and then you have to manually build a LogEvent and... well, it gets messy.  I want something simple and sexy so I can say:     _log.Log(someLevel, "This will be logged at whatever level I choose at runtime!");     Now, some purists out there might say you should always know what level you want to log at, and for the most part I agree with them.  For the most party the ILog interface satisfies 99% of my needs.  In fact, for most application logging yes you do always know the level you will be logging at, but when writing a utility class, you may not always know what level your user wants. I'll tell you, one of my favorite things is to write reusable components.  If I had my druthers I'd write framework libraries and shared components all day!  And being able to easily log at a runtime-chosen level is a big need for me.  After all, if I want my code to really be re-usable, I shouldn't force a user to deal with the logging level I choose. One of my favorite uses for this is in Interceptors -- I'll describe Interceptors in my next post and some of my favorites -- for now just know that an Interceptor wraps a class and allows you to add functionality to an existing method without changing it's signature.  At the risk of over-simplifying, it's a very generic implementation of the Decorator design pattern. So, say for example that you were writing an Interceptor that would time method calls and emit a log message if the method call execution time took beyond a certain threshold of time.  For instance, maybe if your database calls take more than 5,000 ms, you want to log a warning.  Or if a web method call takes over 1,000 ms, you want to log an informational message.  This would be an excellent use of logging at a generic level. So here was my personal wish-list of requirements for my task: Be able to determine if a runtime-specified logging level is enabled. Be able to log generically at a runtime-specified logging level. Have the same look-and-feel of the existing Debug, Info, Warn, Error, and Fatal calls.    Having the ability to also determine if logging for a level is on at runtime is also important so you don't spend time building a potentially expensive logging message if that level is off.  Consider an Interceptor that may log parameters on entrance to the method.  If you choose to log those parameter at DEBUG level and if DEBUG is not on, you don't want to spend the time serializing those parameters. Now, mine may not be the most elegant solution, but it performs really well since the enum I provide all uses contiguous values -- while it's never guaranteed, contiguous switch values usually get compiled into a jump table in IL which is VERY performant - O(1) - but even if it doesn't, it's still so fast you'd never need to worry about it. So first, I need a way to let users pass in logging levels.  Sure, log4net has a Level class, but it's a class with static members and plus it provides way too many options compared to ILog interface itself -- and wouldn't perform as well in my level-check -- so I define an enum like below.     namespace Shared.Logging.Extensions     {         // enum to specify available logging levels.         public enum LoggingLevel         {             Debug,             Informational,             Warning,             Error,             Fatal         }     } Now, once I have this, writing the extension methods I need is trivial.  Once again, I would typically /// comment fully, but I'm eliminating for blogging brevity:     namespace Shared.Logging.Extensions     {         // the extension methods to add functionality to the ILog interface         public static class LogExtensions         {             // Determines if logging is enabled at a given level.             public static bool IsLogEnabled(this ILog logger, LoggingLevel level)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         return logger.IsDebugEnabled;                     case LoggingLevel.Informational:                         return logger.IsInfoEnabled;                     case LoggingLevel.Warning:                         return logger.IsWarnEnabled;                     case LoggingLevel.Error:                         return logger.IsErrorEnabled;                     case LoggingLevel.Fatal:                         return logger.IsFatalEnabled;                 }                                 return false;             }             // Logs a simple message - uses same signature except adds LoggingLevel             public static void Log(this ILog logger, LoggingLevel level, object message)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.Debug(message);                         break;                     case LoggingLevel.Informational:                         logger.Info(message);                         break;                     case LoggingLevel.Warning:                         logger.Warn(message);                         break;                     case LoggingLevel.Error:                         logger.Error(message);                         break;                     case LoggingLevel.Fatal:                         logger.Fatal(message);                         break;                 }             }             // Logs a message and exception to the log at specified level.             public static void Log(this ILog logger, LoggingLevel level, object message, Exception exception)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.Debug(message, exception);                         break;                     case LoggingLevel.Informational:                         logger.Info(message, exception);                         break;                     case LoggingLevel.Warning:                         logger.Warn(message, exception);                         break;                     case LoggingLevel.Error:                         logger.Error(message, exception);                         break;                     case LoggingLevel.Fatal:                         logger.Fatal(message, exception);                         break;                 }             }             // Logs a formatted message to the log at the specified level.              public static void LogFormat(this ILog logger, LoggingLevel level, string format,                                          params object[] args)             {                 switch (level)                 {                     case LoggingLevel.Debug:                         logger.DebugFormat(format, args);                         break;                     case LoggingLevel.Informational:                         logger.InfoFormat(format, args);                         break;                     case LoggingLevel.Warning:                         logger.WarnFormat(format, args);                         break;                     case LoggingLevel.Error:                         logger.ErrorFormat(format, args);                         break;                     case LoggingLevel.Fatal:                         logger.FatalFormat(format, args);                         break;                 }             }         }     } So there it is!  I didn't have to modify the log4net source code, so if a new version comes out, i can just add the new assembly with no changes.  I didn't have to subclass and worry about developers not calling my sub-class instead of the original.  I simply provide the extension methods and it's as if the long lost extension methods were always a part of the ILog interface! Consider a very contrived example using the original interface:     // using the original ILog interface     public class DatabaseUtility     {         private static readonly ILog _log = LogManager.Create(typeof(DatabaseUtility));                 // some theoretical method to time         IDataReader Execute(string statement)         {             var timer = new System.Diagnostics.Stopwatch();                         // do DB magic                                    // this is hard-coded to warn, if want to change at runtime tough luck!             if (timer.ElapsedMilliseconds > 5000 && _log.IsWarnEnabled)             {                 _log.WarnFormat("Statement {0} took too long to execute.", statement);             }             ...         }     }     Now consider this alternate call where the logging level could be perhaps a property of the class          // using the original ILog interface     public class DatabaseUtility     {         private static readonly ILog _log = LogManager.Create(typeof(DatabaseUtility));                 // allow logging level to be specified by user of class instead         public LoggingLevel ThresholdLogLevel { get; set; }                 // some theoretical method to time         IDataReader Execute(string statement)         {             var timer = new System.Diagnostics.Stopwatch();                         // do DB magic                                    // this is hard-coded to warn, if want to change at runtime tough luck!             if (timer.ElapsedMilliseconds > 5000 && _log.IsLogEnabled(ThresholdLogLevel))             {                 _log.LogFormat(ThresholdLogLevel, "Statement {0} took too long to execute.",                     statement);             }             ...         }     } Next time, I'll show one of my favorite uses for these extension methods in an Interceptor.

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  • ASP.NET MVC: Using jQuery context menu with tables

    - by DigiMortal
    I needed to add context menus to some tables of my intranet application. After trying some components I found one that does everything I need and has no overhead. In this posting I will show you how to use jQuery context menu plug-in and how to attach it to tables. I found context menu plug-in by Chris Domigan and it was very easy to integrate to my application (when comparing some other plug-ins that work only on demo pages and in simple scenarios). Thanks, Chris, for great work! Now let’s use this context menu plug-in with table. Before we go on let’s see what we are trying to achieve. The following screenshot fragment shows simple context menu that we want to attach to our table. And when we click some menu option then something should happen too. :) Installing context menu plug-in Download plug-in (if download link is broken then open demo page and I think you know how to get plug-in from there). Copy jquery.contextmenu.js to your scripts folder. Include it in your masterpage or in the page where you plan to use context menus. Make sure plug-in is included correctly (use Firebug or some other tool you like). Save the page. Defining context menu Now let’s define context menu. Here is fragment on context menu definition from my code. <div class="contextMenu" id="myMenu1">     <ul>     <li id="email"><img src="/img/e-mail.png" />E-mail</li>     <li id="homepage"><img src="/img/homepage.png" />Homepage</li>     </ul> </div> div with id myMenu1 is container of context menu. Unordered list inside container defines items in context menu – simple and elegant! Adding context menu to table I have table with persons. It is simple HTML. I omitted commands column from this and the next table to keep them simple and more easily readable. <table>   <tr>     <th>Name</th>     <th>Short</th>     <th>Address</th>     <th>Mobile</th>     <th>E-mail</th>   </tr>   <% foreach(var person in Model.Results) { %>   <tr>     <td><%=person.FullName %></td>     <td><%=person.ShortName %></td>     <td><%=person.FullAddress %></td>     <td><%=person.Mobile %></td>     <td><%=person.Email %></td>   </tr>   <% } %> </table> To get context menu linked to table rows first cells we need to specify class for cells and ID. We need ID because we have to know later which ID has the row on which user selected something from context menu. <table>   <tr>     <th>Name</th>     <th>Short</th>     <th>Address</th>     <th>Mobile</th>     <th>E-mail</th>   </tr>   <% foreach(var person in Model.Results) { %>   <tr>     <td class="showContext" id="<%= person.Id %>"><%=person.FullName %></td>     <td><%=person.ShortName %></td>     <td><%=person.FullAddress %></td>     <td><%=person.Mobile %></td>     <td><%=person.Email %></td>   </tr>   <% } %> </table> Now we have only one thing to do – we have to write some code that attaches context menu to table cells. Catching context menu events Now we will make everything work. Relax, it is only couple of lines of code, thank to jQuery. <script type="text/javascript">   $(document).ready(function () {     $('td.showContext').contextMenu('myMenu1', {         bindings: {         'email': function (t) {           document.location.href = '/contact/sendmail/' + t.id;         },         'homepage': function (t) {           document.location.href = '/contact/homepage/' + t.id;         }       }     });   }); </script> I think that first lines doesn’t need any comments. Take a look at bindings. We gave ID to table cells because it is carried also to bound events. We can use also more complex ID-s if we have more than one table with context menus on our form. Now we are done. Save all files, compile solution, run it and try out how context menu works. Conclusion We saw than using jQuery with context menu component allows us easily create powerful context menus for our user interfaces. Context menu was very easy to define. We were also able to attach context menu to table and use ID of current row entity also in events of context menu. To achieve this we needed only some minor modifications in view and couple of lines of JavaScript.

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