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  • explicit copy constructor or implicit parameter by value

    - by R Samuel Klatchko
    I recently read (and unfortunately forgot where), that the best way to write operator= is like this: foo &operator=(foo other) { swap(*this, other); return *this; } instead of this: foo &operator=(const foo &other) { foo copy(other); swap(*this, copy); return *this; } The idea is that if operator= is called with an rvalue, the first version can optimize away construction of a copy. So when called with a rvalue, the first version is faster and when called with an lvalue the two are equivalent. I'm curious as to what other people think about this? Would people avoid the first version because of lack of explicitness? Am I correct that the first version can be better and can never be worse?

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  • Ocaml Pattern Matching

    - by Atticus
    Hey guys, I'm pretty new to OCaml and pattern matching, so I was having a hard time trying to figure this out. Say that I have a list of tuples. What I want to do is match a parameter with one of the tuples based on the first element in the tuple, and upon doing so, I want to return the second element of the tuple. So for example, I want to do something like this: let list = [ "a", 1; "b", 2"; "c", 3; "d", 4 ] ;; let map_left_to_right e rules = match e with | first -> second | first -> second | first -> second If I use map_left_to_right "b" list, I want to get 2 in return. I therefore want to list out all first elements in the list of rules and match the parameter with one of these elements, but I am not sure how to do so. I was thinking that I need to use either List.iter or List.for_all to do something like this. Any help would be appreciated. Thanks!

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  • Odd results when searching for numbers using IXSSO.Query

    - by Vic
    Hi, from classic asp on Windows 2008, using an IXSSO.Query, when searching for a string of numbers, for example 10000000001, I receive results that also include variations to this, like 10000000002 10000000003 and so on. If I change the first digit so the search string is 20000000001 I dont get anything. If I keep moving the last digit from my first example to the left, I keep getting hits until I reach the half way point when I get no results! So in other words 10000020000 will return results like in the first example but 10000200000 does not. This all sounds like to me that its doing a match on the first 6 characters and it ignores the rest... Here is relevant parts of the Set oQuery = Server.CreateObject("IXSSO.Query") oQuery.Catalog = SEARCH_CATALOG oQuery.Query = "@all " & searchstr Set oRS = oQuery.CreateRecordset("nonsequential") Anyone got any ideas and/or suggestions? Thanks, Vic.

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  • Improving field get and set performance with ASM or Javassist

    - by ng
    I would like to avoid reflection in an open source project I am developing. Here I have classes like the following. public class PurchaseOrder { @Property private Customer customer; @Property private String name; } I scan for the @Property annotation to determine what I can set and get from the PurchaseOrder reflectively. There are many such classes all using java.lang.reflect.Field.get() and java.lang.reflect.Field.set(). Ideally I would like to generate for each property an invoker like the following. public interface PropertyAccessor<S, V> { public void set(S source, V value); public V get(S source); } Now when I scan the class I can create a static inner class of PurchaseOrder like so. static class customer_Field implements PropertyAccessor<PurchaseOrder, Customer> { public void set(PurchaseOrder order, Customer customer) { order.customer = customer; } public Customer get(PurchaseOrder order) { return order.customer; } } With these I totally avoid the cost of reflection. I can now set and get from my instances with native performance. Can anyone tell me how I would do this. A code example would be great. I have searched the net for a good example but can find nothing like this. The ASM and Javasist examples are pretty poor also. The key here is that I have an interface that I can pass around. So I can have various implementations, perhaps one with Java Reflection as a default, one with ASM, and one with Javassist? Any help would be greatly appreciated.

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  • postgres - ERROR: operator does not exist

    - by cino21122
    Again, I have a function that works fine locally, but moving it online yields a big fat error... Taking a cue from a response in which someone had pointed out the number of arguments I was passing wasn't accurate, I double-checked in this situation to be certain that I am passing 5 arguments to the function itself... Query failed: ERROR: operator does not exist: point <@> point HINT: No operator matches the given name and argument type(s). You may need to add explicit type casts. The query is this: BEGIN; SELECT zip_proximity_sum('zc', (SELECT g.lat FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1), (SELECT g.lon FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1), (SELECT m.zip FROM geocoded g LEFT JOIN masterfile m ON g.recordid = m.id WHERE m.zip = '10050' ORDER BY m.id LIMIT 1) ,10); The PG function is this: CREATE OR REPLACE FUNCTION zip_proximity_sum(refcursor, numeric, numeric, character, numeric) RETURNS refcursor AS $BODY$ BEGIN OPEN $1 FOR SELECT r.zip, point($2,$3) <@> point(g.lat, g.lon) AS distance FROM geocoded g LEFT JOIN masterfile r ON g.recordid = r.id WHERE (geo_distance( point($2,$3),point(g.lat,g.lon)) < $5) ORDER BY r.zip, distance; RETURN $1; END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 100;

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  • How to debug and detect hang issue

    - by igor
    I am testing my application (Windows 7, WinForms, Infragistics controls, C#, .Net 3.5). I have two monitors and my application saves and restores forms' position on the first or second monitors. So I physically switched off second monitor and disabled it at Screen Resolution on the windows display settings form. I need to know it is possible for my application to restore windows positions (for those windows that were saved on the second monitor) to the first one. I switched off second monitor and press Detect to apply hardware changes. Then Windows switched OFF the first monitor for a few seconds to apply new settings. When the first monitor screen came back, my application became unresponsive. My application was launched in debug mode, so I tried to navigate via stack and threads (Visual Studio 2008), paused application, started and did not find any thing that help me to understand why my application is not responsive. Could somebody help my how to detect the source of issue.

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  • Problem storing a hash in DB using Storable::nfreeze in Perl

    - by Sam
    I want to insert a hash in the db using Storable::nfreeze but the data is not inserted properly. My code is as follows: %rec=(); $rec{'name'} = 'my name'; $rec{'address'} = 'my address'; my $order1 = new Order(); $order1->set_session(\%rec); $self->createOrder($order1); sub createOrder { my $self = $_[0]; my $order = $_[1]; # Retrieve the fields to insert into the database. my $st = $dbh->prepare("insert into order (session,.......) values(?,........)"); my $session = %{$order->get_session()}; $st->execute(&Storable::nfreeze(\%session),.....); $st->finish(); } sub getOrder { ... my $session = &Storable::thaw( $ref->{'session'} ); ..... } The thaw is working fine because I tested it withe some rows that have been inserted correctly, but when I try to get a row that was inserted using the createOrder subroutine, I get an error saying: Storable binary image v36.65 more recent than I am (v2.7) at blib/lib/Storable.pm (autosplit into blib/lib/auto/Storable/thaw.al) line 415 The error comes from the line that have thaw. The nfreeze did not store the hash properly. Can someone point me to what I'm doing wrong in the createOrder subroutine? I know the module version have nothing to do with the problem.

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  • Jquery date in a adropdown with interval

    - by Zoom Pat
    I am trying to use Jquery to display dates in a dropdown with interval of half month... so the first value would be the coming month's 1st, then second will be the coming month's 15th and third value would be next to next month's first and so on... If today date is less than 15th then the first value would be the 15th of current month. What will be the best or a cleaner way to do this... (want to display in the dropdown) Thanks

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  • Writing a JavaScript zip code validation function

    - by mkoryak
    I would like to write a JavaScript function that validates a zip code, by checking if the zip code actually exists. Here is a list of all zip codes: http://www.census.gov/tiger/tms/gazetteer/zips.txt (I only care about the 2nd column) This is really a compression problem. I would like to do this for fun. OK, now that's out of the way, here is a list of optimizations over a straight hashtable that I can think of, feel free to add anything I have not thought of: Break zipcode into 2 parts, first 2 digits and last 3 digits. Make a giant if-else statement first checking the first 2 digits, then checking ranges within the last 3 digits. Or, covert the zips into hex, and see if I can do the same thing using smaller groups. Find out if within the range of all valid zip codes there are more valid zip codes vs invalid zip codes. Write the above code targeting the smaller group. Break up the hash into separate files, and load them via Ajax as user types in the zipcode. So perhaps break into 2 parts, first for first 2 digits, second for last 3. Lastly, I plan to generate the JavaScript files using another program, not by hand. Edit: performance matters here. I do want to use this, if it doesn't suck. Performance of the JavaScript code execution + download time. Edit 2: JavaScript only solutions please. I don't have access to the application server, plus, that would make this into a whole other problem =)

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  • ConcurrentLinkedQueue$Node remains in heap after remove()

    - by action8
    I have a multithreaded app writing and reading a ConcurrentLinkedQueue, which is conceptually used to back entries in a list/table. I originally used a ConcurrentHashMap for this, which worked well. A new requirement required tracking the order entries came in, so they could be removed in oldest first order, depending on some conditions. ConcurrentLinkedQueue appeared to be a good choice, and functionally it works well. A configurable amount of entries are held in memory, and when a new entry is offered when the limit is reached, the queue is searched in oldest-first order for one that can be removed. Certain entries are not to be removed by the system and wait for client interaction. What appears to be happening is I have an entry at the front of the queue that occurred, say 100K entries ago. The queue appears to have the limited number of configured entries (size() == 100), but when profiling, I found that there were ~100K ConcurrentLinkedQueue$Node objects in memory. This appears to be by design, just glancing at the source for ConcurrentLinkedQueue, a remove merely removes the reference to the object being stored but leaves the linked list in place for iteration. Finally my question: Is there a "better" lazy way to handle a collection of this nature? I love the speed of the ConcurrentLinkedQueue, I just cant afford the unbounded leak that appears to be possible in this case. If not, it seems like I'd have to create a second structure to track order and may have the same issues, plus a synchronization concern.

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  • Oracle command hangs when using view for "WHILE x IN..." subquery

    - by Calvin Fisher
    I'm working on a web service that fetches data from an oracle data source in chunks and passes it back to an indexing/search tool in XML format. I'm the C#/.NET guy, and am kind of fuzzy on parts of Oracle. Our Oracle team gave us the following script to run, and it works well: SELECT ROWID, [columns] FROM [table] WHERE ROWID IN ( SELECT ROWID FROM ( SELECT ROWID FROM [table] WHERE ROWID > '[previous_batch_last_rowid]' ORDER BY ROWID ) WHERE ROWNUM <= 10000 ) ORDER BY ROWID 10,000 rows is an arbitrary but reasonable chunk size and ROWID is sufficiently unique for our purposes to use as a UID since each indexing run hits only one table at a time. Bracketed values are filled in programmatically by the web service. Now we're going to start adding views to the indexing, each of which will union a few separate tables. Since ROWID would no longer function as a unique identifier, they added a column to the views (VIEW_UNIQUE_ID) that concatenates the ROWIDs from the component tables to construct a UID for each union. But this script does not work, even though it follows the same form as the previous one: SELECT VIEW_UNIQUE_ID, [columns] FROM [view] WHERE VIEW_UNIQUE_ID IN ( SELECT VIEW_UNIQUE_ID FROM ( SELECT VIEW_UNIQUE_ID FROM [view] WHERE ROWID > '[previous_batch_last_view_unique_id]' ORDER BY VIEW_UNIQUE_ID ) WHERE ROWNUM <= 10000 ) ORDER BY VIEW_UNIQUE_ID It hangs indefinitely with no response from the Oracle server. I've waited 20+ minutes and the SQLTools dialog box indicating a running query remains the same, with no progress or updates. I've tested each subquery independently and each works fine and takes a very short amount of time (<= 1 second), so the view itself is sound. But as soon as the inner two SELECT queries are added with "WHERE VIEW_UNIQUE_ID IN...", it hangs. Why doesn't this query work for views? In what important way are they not interchangeable here?

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  • What's wrong with this jQuery fading gallery code?

    - by Meep3D
    So I am creating a fading gallery and am a bit of a noob to javascript (but not to programming). I have no idea what is wrong though. Here's the function in question: /* */ function show_next () { // Hide current $('.s_gallery_images li.s_current').fadeTo(200, .2); $('.s_gallery_images li.s_current').css("border","1px green solid"); // if ($('.s_gallery_images li').hasClass ('.s_current')) { console.log ('Incrementing existing'); // Class already exists $('.s_current:first').removeClass('s_current').next().addClass('s_current'); // Was that the last one? if ($('.s_gallery_images li').hasClass ('.s_current')) { console.log ('Current found'); } else { // Class doesn't exist - add to first $('.s_gallery_images li:first').addClass ('.s_current'); console.log ('Wrapping'); } } else { console.log ('Adding new class'); // Class doesn't exist - add to first $('.s_gallery_images li:first').addClass ('.s_current'); } // Show new marked item $('.s_gallery_images li.s_current').fadeTo(200, .8); } The HTML is a very simple: <ul class="s_gallery_images"> <li><img src="imagename" alt="alt" /></li> <li><img src="imagename" alt="alt" /></li> <li><img src="imagename" alt="alt" /></li> </ul> And it displays the list and the images fine. I am using firebugs console.log for debugging, plus have a class set for s_current (bright border) but nothing happens at all. The firebug console log says: Adding New Class Incrementing Existing Current Found Incrementing Existing Current Found Incrementing Existing Current Found Incrementing Existing Current Found ... to infinity The function is called on a setInterval timer, and as far as I can tell it should be working (and I have done something similar before), but it just isn't happening :(

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  • Good Starting Points for Optimizing Database Calls in Ruby on Rails?

    - by viatropos
    I have a menu in Rails which grabs a nested tree of Post models, each which have a Slug model associated via a polymorphic association (using the friendly_id gem for slugs and awesome_nested_set for the tree). The database output in development looks like this (here's the full gist): SQL (0.4ms) SELECT COUNT(*) AS count_id FROM "posts" WHERE ("posts".parent_id = 39) CACHE (0.0ms) SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 13) LIMIT 1 CACHE (0.0ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 13 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 Slug Load (0.4ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 40 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 SQL (0.3ms) SELECT COUNT(*) AS count_id FROM "posts" WHERE ("posts".parent_id = 40) CACHE (0.0ms) SELECT "posts".* FROM "posts" WHERE ("posts"."id" = 13) LIMIT 1 CACHE (0.0ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 13 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 Slug Load (0.4ms) SELECT "slugs".* FROM "slugs" WHERE ("slugs".sluggable_id = 41 AND "slugs".sluggable_type = 'Post') ORDER BY id DESC LIMIT 1 ... Rendered shared/_menu.html.haml (907.6ms) What are some quick things I should always do to optimize this from the start (easy things)? Some things I'm thinking now are: Can Rails 3 eager load the whole Post tree + associated Slugs in one DB call? Can I do that easily with named scopes or custom SQL? What is best practice in this situation? Not really thinking about memcached in this situation as that can be applied to much more than just this.

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  • DotNetNuke + XPath = Custom navigation menu DNNMenu HTML render

    - by Rui Santos
    I'm developing a skin for DotNetNuke 5 using the Component DNN Done Right menu by Mark Alan which uses XSL-T to convert the XML sitemap into an HTML navigation. The XML sitemap outputs the following structure: <Root > <root > <node id="40" text="Home" url="http://localhost/dnn/Home.aspx" enabled="1" selected="0" breadcrumb="0" first="1" last="0" only="0" depth="0" > <node id="58" text="Child1" url="http://localhost/dnn/Home/Child1.aspx" enabled="1" selected="0" breadcrumb="0" first="1" last="0" only="0" depth="1" > <keywords >Child1</keywords> <description >Child1</description> <node id="59" text="Child1 SubItem1" url="http://localhost/dnn/Home/Child1/Child1SubItem1.aspx" enabled="1" selected="0" breadcrumb="0" first="1" last="0" only="0" depth="2" > <keywords >Child1 SubItem1</keywords> <description >Child1 SubItem1</description> </node> <node id="60" text="Child1 SubItem2" url="http://localhost/dnn/Home/Child1/Child1SubItem2.aspx" enabled="1" selected="0" breadcrumb="0" first="0" last="0" only="0" depth="2" > <keywords >Child1 SubItem2</keywords> <description >Child1 SubItem2</description> </node> <node id="61" text="Child1 SubItem3" url="http://localhost/dnn/Home/Child1/Child1SubItem3.aspx" enabled="1" selected="0" breadcrumb="0" first="0" last="1" only="0" depth="2" > <keywords >Child1 SubItem3</keywords> <description >Child1 SubItem3</description> </node> </node> <node id="65" text="Child2" url="http://localhost/dnn/Home/Child2.aspx" enabled="1" selected="0" breadcrumb="0" first="0" last="1" only="0" depth="1" > <keywords >Child2</keywords> <description >Child2</description> <node id="66" text="Child2 SubItem1" url="http://localhost/dnn/Home/Child2/Child2SubItem1.aspx" enabled="1" selected="0" breadcrumb="0" first="1" last="0" only="0" depth="2" > <keywords >Child2 SubItem1</keywords> <description >Child2 SubItem1</description> </node> <node id="67" text="Child2 SubItem2" url="http://localhost/dnn/Home/Child2/Child2SubItem2.aspx" enabled="1" selected="0" breadcrumb="0" first="0" last="1" only="0" depth="2" > <keywords >Child2 SubItem2</keywords> <description >Child2 SubItem2</description> </node> </node> </node> </root> </Root> My Goal is to render this XML block into this HTML Navigation structure only using UL's LI's, etc.. <ul id="topnav"> <li> <a href="#" class="home">Home</a> <!-- Parent Node - Depth0 --> <div class="sub"> <ul> <li><h2><a href="#">Child1</a></h2></li> <!-- Parent Node 1 - Depth1 --> <li><a href="#">Child1 SubItem1</a></li> <!-- ChildNode - Depth2 --> <li><a href="#">Child1 SubItem2</a></li> <!-- ChildNode - Depth2 --> <li><a href="#">Child1 SubItem3</a></li ><!-- ChildNode - Depth2 --> </ul> <ul> <li><h2><a href="#">Child2</a></h2></li> <!-- Parent Node 2 - Depth1 --> <li><a href="#">Child2 SubItem1</a></li> <!-- ChildNode - Depth2 --> <li><a href="#">Child2 SubItem2</a></li> <!-- ChildNode - Depth2 --> </ul> </div> </li> </ul> Can anyone help with the XSL coding? I'm just starting now with XSL..

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  • problem storing a hash in DB using Storage::nfreeze Perl

    - by Sam
    Hello, I want to insert a hash in the db using Storage::nfreeze but the data is not inserted properly. the code is as follow: %rec=(); $rec{'name'} = 'my name'; $rec{'address'} = 'my address'; my $order1 = new Order(); $order1->set_session(\%rec); $self->createOrder($order1); sub createOrder { my $self = $_[0]; my $order = $_[1]; # Retrieve the fields to insert into the database. my $st = $dbh->prepare("insert into order (session,.......) values(?,........)"); my $session = %{$order->get_session()}; $st->execute(&Storable::nfreeze(\%session),.....); $st->finish(); } sub getOrder { ... my $session = &Storable::thaw( $ref->{'session'} ); ..... } the thaw is working fine because I tested it withe some rows that have been inserted correctly. but when I try to get a row that was inserted using the createOrder subroutine, I get an error saying" Storable binary image v36.65 more recent than I am (v2.7) at blib/lib/Storable.pm (autosplit into blib/lib/auto/Storable/thaw.al) line 415 the error comes from the line that have thaw. the nfreeze did not store the hash properly. Can someone point me to what i m doing wrong in the createOrder subroutine? Thanks in advance. I know the module version have nothing to do with the problem.

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  • User jQuery to get nested elements from XML

    - by Dkong
    I'm spinning my wheels on this. How do I get the values from the following nested elements from the XML below (I've also put my code below)? I am after the "descShort" value and then the capital "Last" and capital "change" : <indices> <index> <code>DJI</code> <exchange>NYSE</exchange> <liveness>DELAYED</liveness> <indexDesc> <desc>Dow Jones Industrials</desc> <descAbbrev>DOW JONES</descAbbrev> <descShort>DOW JONES</descShort> <firstActive></firstActive> <lastActive></lastActive> </indexDesc> <indexQuote> <capital> <first>11144.57</first> <high>11153.79</high> <low>10973.92</low> <last>11018.66</last> <change>-125.9</change> <pctChange>-1.1%</pctChange> </capital> <gross> <first>11144.57</first> <high>11153.79</high> <low>10973.92</low> <last>11018.66</last> <change>-125.9</change> <pctChange>-1.1%</pctChange> </gross> <totalEvents>4</totalEvents> <lastChanged>16-Apr-2010 16:03:00</lastChanged> </indexQuote> </index> <index> <code>XAO</code> <exchange>ASX</exchange> <liveness>DELAYED</liveness> <indexDesc> <desc>ASX All Ordinaries</desc> <descAbbrev>All Ordinaries</descAbbrev> <descShort>ALL ORDS</descShort> <firstActive>06-Mar-1970</firstActive> <lastActive></lastActive> </indexDesc> <indexQuote> <capital> <first>5007.30</first> <high>5007.30</high> <low>4934.00</low> <last>4939.40</last> <change>-67.9</change> <pctChange>-1.4%</pctChange> </capital> <gross> <first>5007.30</first> <high>5007.30</high> <low>4934.00</low> <last>4939.40</last> <change>-67.9</change> <pctChange>-1.4%</pctChange> </gross> <totalEvents>997</totalEvents> <lastChanged>19-Apr-2010 17:02:54</lastChanged> </indexQuote> </index> $.ajax({ type: "GET", url: "stockindices.xml", dataType: "xml", success: function(xml) { $(xml).find('index').each(function(){ var self = $(this); var code = self.find('indexDesc'); $(code).find('indexDesc').each(function(){ alert(self.find('descShort').text()); }); $('<span class=\"tickerItem\"></span>').html(values[0].text()).appendTo('#marq'); }); } });

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  • jQuery fadeIn() not working in IE

    - by Rob Bennet
    [js] $(document).ready(function() { //Default Action $(".tab_content").hide(); //Hide all content $("ul.tabs li:first").addClass("active").show(); //Activate first tab $(".tab_content:first").show(); //Show first tab content //On Click Event $("ul.tabs li").click(function() { $("ul.tabs li").removeClass("active"); //Remove any "active" class $(this).addClass("active"); //Add "active" class to selected tab $(".tab_content").hide(); //Hide all tab content var activeTab = $(this).find("a").attr("href"); //Find the rel attribute value to identify the active tab + content $(activeTab).fadeIn("slow"); //Fade in the active content return false; }); }); [/js] Works in everything but IE?

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  • posmax: like argmax but gives the position(s) of the element x for which f[x] is maximal

    - by dreeves
    Mathematica has a built-in function ArgMax for functions over infinite domains, based on the standard mathematical definition. The analog for finite domains is a handy utility function. Given a function and a list (call it the domain of the function), return the element(s) of the list that maximize the function. Here's an example of finite argmax in action: http://stackoverflow.com/questions/471029/canonicalize-nfl-team-names/472213#472213 And here's my implementation of it (along with argmin for good measure): (* argmax[f, domain] returns the element of domain for which f of that element is maximal -- breaks ties in favor of first occurrence. *) SetAttributes[{argmax, argmin}, HoldFirst]; argmax[f_, dom_List] := Fold[If[f[#1]>=f[#2], #1, #2]&, First[dom], Rest[dom]] argmin[f_, dom_List] := argmax[-f[#]&, dom] First, is that the most efficient way to implement argmax? What if you want the list of all maximal elements instead of just the first one? Second, how about the related function posmax that, instead of returning the maximal element(s), returns the position(s) of the maximal elements?

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  • Discovering a functional algorithm from a mutable one

    - by Garrett Rowe
    This isn't necessarily a Scala question, it's a design question that has to do with avoiding mutable state, functional thinking and that sort. It just happens that I'm using Scala. Given this set of requirements: Input comes from an essentially infinite stream of random numbers between 1 and 10 Final output is either SUCCEED or FAIL There can be multiple objects 'listening' to the stream at any particular time, and they can begin listening at different times so they all may have a different concept of the 'first' number; therefore listeners to the stream need to be decoupled from the stream itself. Pseudocode: if (first number == 1) SUCCEED else if (first number >= 9) FAIL else { first = first number rest = rest of stream for each (n in rest) { if (n == 1) FAIL else if (n == first) SUCCEED else continue } } Here is a possible mutable implementation: sealed trait Result case object Fail extends Result case object Succeed extends Result case object NoResult extends Result class StreamListener { private var target: Option[Int] = None def evaluate(n: Int): Result = target match { case None => if (n == 1) Succeed else if (n >= 9) Fail else { target = Some(n) NoResult } case Some(t) => if (n == t) Succeed else if (n == 1) Fail else NoResult } } This will work but smells to me. StreamListener.evaluate is not referentially transparent. And the use of the NoResult token just doesn't feel right. It does have the advantage though of being clear and easy to use/code. Besides there has to be a functional solution to this right? I've come up with 2 other possible options: Having evaluate return a (possibly new) StreamListener, but this means I would have to make Result a subtype of StreamListener which doesn't feel right. Letting evaluate take a Stream[Int] as a parameter and letting the StreamListener be in charge of consuming as much of the Stream as it needs to determine failure or success. The problem I see with this approach is that the class that registers the listeners should query each listener after each number is generated and take appropriate action immediately upon failure or success. With this approach, I don't see how that could happen since each listener is forcing evaluation of the Stream until it completes evaluation. There is no concept here of a single number generation. Is there any standard scala/fp idiom I'm overlooking here?

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  • how to push one view to another view?

    - by MD
    In my application there are two view.First view na dsecond view. In my second view there is one time for 60 sec.When i go first view to second view then timr is start.when i back to first view thne timer is running in background.when timer is over then one popup is generated.When i click on pop up(ok button) then i want to go in second view.Acctully pop is in second view. How to solve this problem

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  • jQuery, get table cell at specific index

    - by Jarek Waliszko
    Hello, I know that I can get first or last table cell (ex for last row) using jquery expression like below: first cell: $('#table tr:last td:first') or last cell: $('#table tr:last td:last') Can I get cell at specific index, for example index 2, using similliar expression: ex: $('#table tr:last td:[2]')... Regards.

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  • Why my events aren't registered after postback?

    - by lucian.jp
    I have a problem where I have a page with a checkbox : <asp:CheckBox runat="server" ID="chkSelectAll" OnCheckedChanged="chkSelectAll_CheckedChanged" EnableViewState="true" Text='<%# CommonFunctions.GetText(Page, "CreateTask", "chkSelectAll.text") %>' AutoPostBack="true" /> First I had the problem that when the event was raised the checkbox wasn't keeping the checked property value. This is still strange because nowhere in the application we set the EnableViewState to false and by default it should be true. Well this behavior was fixed by puting EnableViewState="true". So now, I have a checkbox that when I first load the page, wworks correctly. I check the box, the event is raised Checked property valu is good and the method is executed. Postback completes and renders the page. I check the box back to false, the event is not triggered and the page is reloaded with the previous data but the Checked Property stays at true. So after the first postback I seem to loose behavior of event and ViewState. We suspect the fact that we move dynamically the controls in the page (See answer here) But this suspicion doesn't explain why everything works perfectly after the first load and stops working after first PostBack. EDIT CODE SAMPLE I created a test project where you can experience my problem. At load if you check any checkbox both raise their respective event. After postback only the second raise both events. I seem to have a problem when I register the events after moving control.

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  • Join two tables with same # of row but sorted for NULL

    - by VISQL
    I need to join two tables with the same number of rows. Each table has 1 column. There is NO CONNECTING COLUMN to reference for a join. I need to join them side by side because each table was sorted separately so that numeric values are at the top in descinding order. The Table Earners has income values from say 200K down to 0. I cannot just select using 2 cases, because then I will have my first row with Incomes above 100K, but the first 20 or so entries in the second row are NULL. I want the second row to also be sorted descending. I looked up using ORDER BY within CASE but there is no such thing. I have tried to read about row_number() but none of the examples seem to match or make sense. drop table #20plus select case when Income >= 20000 AND Income < 100000 then Income end as 'mula' into #20plus from Earners order by mula desc drop table #100plus select case when Income >= 100000 then Income end as 'dinero' into #100plus from Earners order by dinero desc Select A.dinero, B.mula FROM #100plus as A JOIN #20plus as B ON A.????? = B.????? Since both A and B are sorted descending, moving all NULL to the bottom, what can I reference to join the two tables? Previous output using one SELECT statement with 2 CASE statements dinero mula 2.12688e+007 NULL 1.80031e+007 NULL 1.92415e+006 NULL … … NULL 93530.7 NULL 91000 NULL 84500 Desired output using one SELECT statement after creating two temp TABLES dinero mula 2.12688e+007 93530.7 1.80031e+007 91000 1.92415e+006 84500 … 82500 NULL 82000 NULL … NULL NULL This is Microsoft SQL Server 2008. I'm super new to this, so please give an answer as clear and simplified as possible. Thank you.

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  • mod_rewrite with location-based ACL in apache?

    - by Alexey
    Hi. There is a CGI-script that provides some API for our customers. Call syntax is: script.cgi?module=<str>&func=<str>[&other-options] The task is to make different authentiction rules for different modules. Optionally, it will be great to have nice URLs. My config: <VirtualHost *:80> DocumentRoot /var/www/example ServerName example.com # Global policy is to deny all <Location /> Order deny,allow Deny from all </Location> # doesn't work :( <Location /api/foo> Order deny,allow Deny from all Allow from 127.0.0.1 </Location> RewriteEngine On # The only allowed type of requests: RewriteRule /api/(.+?)/(.+) /cgi-bin/api.cgi?module=$1&func=$2 [PT] # All others are forbidden: RewriteRule /(.*) - [F] RewriteLog /var/log/apache2/rewrite.log RewriteLogLevel 5 ScriptAlias /cgi-bin /var/www/example <Directory /var/www/example> Options -Indexes AddHandler cgi-script .cgi </Directory> </VirtualHost> Well, I know that problem is order of processing that directives. <Location>s will be processed after mod_rewrite has done its work. But I believe there is a way to change it. :) Using of standard Order deny,allow + Allow from <something> directives is preferable because it's commonly used in other places like this. Thank you for your attention. :)

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  • How are SQL Server CALs counted?

    - by Sam
    Running a SQL Server, as far as I understand it, you need one CAL for every user who connects to the database server. But what happens if the only computer which is accessing the SQL Server is the server running your business layer? If, for example, you got 1 SQL Server and 1 Business logic server, and 100 Clients who all just query and use the business logic server. No client is using the SQL Server directly, no one is even allowed to contact it. So, since there is only one computer using the SQL server, do I need only 1 CAL??? I somehow can't believe this would count as only 1 CAL needed for the SQL Server, but I would like to know why not.

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