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• Should I put a try-finally block after every Object.Create?

  - by max

  I have a general question about best practice in OO Delphi. Currently, I put try-finally blocks anywhere I create an object to free that object after usage (to avoid memory leaks). E.g.: aObject := TObject.Create; try aOBject.AProcedure(); ... finally aObject.Free; end; instead of: aObject := TObject.Create; aObject.AProcedure(); .. aObject.Free; Do you think it is good practice, or too much overhead? And what about the performance?

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• What goes in to making a web site that needs to scale?

  - by samoz

  I am planning to build an application that will get a large amount of traffic. (Please don't say I won't get traffic, this is for an internal network, so the traffic will be there. Just trying to avoid the 'You won't get that much traffic, don't worry about it.) What sorts of things do I need to do so that it doesn't simply crash under the load of a large amount of users? What becomes the limiting factors? Database stuff? I/O with front end? I've never really developed a serious web app before and am looking for some help.

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• Best way of obfuscating / encrypting form data on the iPhone

  - by cannyboy

  I want to create an app which holds sensitive information (imagine it's bank account details, thought it's not). The user enters this information on a form the first time the app starts up. I want this info to be saved, and available, any time the user uses the app (without having to enter a password). However, if the iPhone has a password lock on it, and is stolen, I don't want the data to be easily accessible from the file system. What is the best way of encrypting or obfuscating the data? There is not a lot of data, just a dozen NSStrings from the UITextFields on the form. I'm aware there are encryption export restrictions on the iPhone for non-US developers (I am in UK), so I would prefer to avoid going jumping through any of Apple's app submission hoops to get it on the store.

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• How do you send an array as part of an (jquery) ajax request

  - by Ankur

  I tried to send an array as part of an ajax request like this: var query = []; // in between I add some values to 'query' $.ajax({ url: "MyServlet", data: query, dataType: "json", success: function(noOfResults) { alert(noOfResults); } }); } I wanted to see what I get back in the servlet, so I used this line: System.out.println(request.getParameterMap().toString()); Which returned {} suggesting an empty map. Firebug tells me I am getting a 400 bad request error If I send a queryString like attribute=value as the 'data' then everything works fine, so it has to do with not being able to send an array as is. What do I have to do to get that data into the servlet for further processing. I don't want to pull it out and turn it into a queryString in the JS if I can avoid it. EDIT: I used the .serializeArray() (jQuery) function before sending the data. I don't get the 400 but nothing useful is being sent through.

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• How do I automatically reset a boolean when any method other is called in C#?

  - by gtaborga

  Hey everyone, Using C#, I need to do some extra work if function A() was called right before function C(). If any other function was called in between A() and C() then I don't want to do that extra work. Any ideas that would require the least amount of code duplication? I'm trying to avoid adding lines like "flag = false;" into every function B1..BN. Here is a very basic example: bool flag = false; void A() { flag = true; } void B1() { ... } void B2() { ... } void C() { if (flag) { //do something } } The above example was just using a simple case but I'm open to using something other than booleans. The important thing is that I want to be able to set and reset a flag of sorts so that C() knows how to behave accordingly. Thank you for your help. If you require clarification I will edit my post.

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• Is there a way to test if a scalar has been stringified or not?

  - by Yobert

  I am writing a thing to output something similar to JSON, from a perl structure. I want the quoting to behave like this: "string" outputs "string" "05" outputs "05" "5" outputs "5" 5 outputs 5 05 outputs 5, or 05 would be acceptable JSON::XS handles this by testing if a scalar has been "stringified" or not, which I think is very cool. But I can't find a way to do this test myself without writing XS, which I'd rather avoid. Is this possible? I can't find this anywhere on CPAN without finding vast pedantry about Scalar::Util::looks_like_number, etc which completely isn't what I want. The only stopgap I can find is Devel::Peek, which feels evil. And also, just like JSON::XS, I'm fine with this secenario: my $a = 5; print $a."\n"; # now $a outputs "5" instead of 5)

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• Thread Suicide on Shutdown?

  - by yar

  I have a java.util.Timer running at a fixed interval. I have added a Runtime#addShutdownHook and it shuts down when the VM ends normally or abnormally. However, it keeps the VM alive when a main terminates, unless I insist by doing a System.exit in the main. Is there any way for me to check if I'm the last Thread standing, or some other way to avoid altering a main that would exit normally on finish? Note: I know a lot of people believe that java.util.Timer is deprecated (it's not), but unless your alternative helps me solve this problem...

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• Websphere/Oracle 11 - much more Heap Usage than with Oracle 10

  - by swalkner

  Hi all, while testing our application with Oracle 11 (previously, we had Oracle 10), we saw that our server uses much more heap space. It seems as it has something to do with T4CConnection; there are 500 objects of T4CConnection allocated. Someone told me, that Oracle 11 is using SoftReferences to keep the connection pool; but we don't need that. Is that correct? Could that be the problem for the increased heap space? If yes - how can we avoid connection pooling? Thanks a lot!!

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• iPhone view architecture question

  - by Joe

  So I have (for instance) three views: A: root view B: a view functionally identical to root C: a data entry view which collects a few piece of info What I'm trying to do is reuse C to supply the data it collects to either A or B. It should supply the data to whichever of the two it is pushed onto. The data for A is similar, but functionally distinct, to what collects for B. Right now, I'm passing data from C to A or B via a singleton class. What I'm trying to avoid is having two instances of C, one to supply data to A and B (because, in actuality, the program will have 5 total views like C. Does the question make sense?

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• HTML chrome:// page with select box, onChange failing

  - by Noitidart

  I have a html page. It is chrome://. I have a select box. Giving it the oncommand attribute won't work. So I have to use onchange however you have the typical problem with onchange where it doesnt work if user uses the keyboard arrows, or letters of items to change things. Is there anyway to attach onCommand to my select box? I want to avoid to use onkeyup as then i have to to validation to see if it really changed (which would require me saving previous values).

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• Tests that are 2-3 times bigger than the testable code

  - by HeavyWave

  Is it normal to have tests that are way bigger than the actual code being tested? For every line of code I am testing I usually have 2-3 lines in the unit test. Which ultimately leads to tons of time being spent just typing the tests in (mock, mock and mock more). Where are the time savings? Do you ever avoid tests for code that is along the lines of being trivial? Most of my methods are less than 10 lines long and testing each one of them takes a lot of time, to the point where, as you see, I start questioning writing most of the tests in the first place. I am not advocating not unit testing, I like it. Just want to see what factors people consider before writing tests. They come at a cost (in terms of time, hence money), so this cost must be evaluated somehow. How do you estimate the savings created by your unit tests, if ever?

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• exactly what does rake db:migrate do?

  - by happythenewsad

  Does rake db:migrate only add new migrations, or does it drop all migrations/changes and build everything new? I think rake is throwing an error because it is trying to access a table attribute in migration 040 that was deleted in migration 042. somehow my DB and rake are out of synch and I want to fix them. for you experts out there - is it common for rake to get out of synch with migrations? how can I avoid this (no, I do not hand-edit my schema or rake files).

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• formatting european characters from JSON results

  - by mlecho

  hi, i am building an application that imports JSON results and parses the objects to a table cell. Nothing fancy, but in my results, many of the terms/names are European with characters such as è or ú which come out as \u00E9 or \u00FA. I think these are ASCII ? or unicode? ( i can never keep em staight). Anyway, like all good NSSTring's, i figured there must be a method to fix this, but i am not finding it....any ideas? I am trying to avoid doing something like this: this posting. Thanks all.

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• Can I reproduce Scala's behavior for == ?

  - by JPP

  In Programming in Scala, I can read that the == operator behaves as if it was defined like this: final def == (that: Any): Boolean = if (null eq this) {null eq that} else {this equals that} But there must actually be compiler magic to avoid null pointer exceptions, right? Is there any way for me to replicate this behavior with pure Scala; i.e., have an operator/method return one thing if the receiver is null and another one if it isn't? What I mean is an actual implementation of null eq this. I suppose I can write a "pimp" and then define the method on the wrapper class, but is there a more direct way to do this?

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• How to address thread-safety of service data used for maintaining static local variables in C++?

  - by sharptooth

  Consider the following scenario. We have a C++ function with a static local variable: void function() { static int variable = obtain(); //blahblablah } the function needs to be called from multiple threads concurrently, so we add a critical section to avoid concurrent access to the static local: void functionThreadSafe() { CriticalSectionLockClass lock( criticalSection ); static int variable = obtain(); //blahblablah } but will this be enough? I mean there's some magic that makes the variable being initialized no more than once. So there's some service data maintained by the runtime that indicates whether each static local has already been initialized. Will the critical section in the above code protect that service data as well? Is any extra protection required for this scenario?

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• maintain formatting entered into an html form?

  - by NickG77

  Im setting up a web form, and I'm trying to have it where visitors can paste their resumes into a text area. Then I want to email the info using php mail(). But the resume info is just stored in the variable as one long string with no formatting. Is there a way I can send the pasted resume text to the client in the resume format? Maintaining all the line breaks and stuff? He wants to avoid having people upload resumes.

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• Any idea why this query always returns duplicate items?

  - by Kardo

  I want to get all Images not used by current ItemID. The this subquery but it also always returns duplicate Images: EDITED select Images.ImageID, Images.ItemStatus, Images.UserName, Images.Url, Image_Item.ItemID, Image_Item.ItemID from Images left join (select ImageID, ItemID, MAX(DateCreated) x from Image_Item where ItemID != '5a0077fe-cf86-434d-9f3b-7ff3030a1b6e' group by ImageID, ItemID having count(*) = 1) image_item on Images.imageid = image_item.imageid where ItemID is not null I guess the problem is with the subquery which I can't avoid duplicate rows: select ImageID, ItemID, MAX(DateCreated) x from Image_Item where ItemID != '5a0077fe-cf86-434d-9f3b-7ff3030a1b6e' group by ImageID, ItemID having count(*) = 1 Result: F2EECBDC-963D-42A7-90B1-4F82F89A64C7 0578AC61-3C32-4A1D-812C-60A09A661E71 F2EECBDC-963D-42A7-90B1-4F82F89A64C7 9A4EC913-5AD6-4F9E-AF6D-CF4455D81C10 42BC8B1A-7430-4915-9CDA-C907CBC76D6A CB298EB9-A105-4797-985E-A370013B684F 16371C34-B861-477C-9A7C-DEB27C8F333D 44E6349B-7EBF-4C7E-B3B0-1C6E2F19992C Table: Images ImageID uniqueidentifier UserName nvarchar(100) DateCreated smalldatetime Url nvarchar(250) ItemStatus char(1) Table: Image_Item ImageID uniqueidentifier ItemID uniqueidentifier UserName nvarchar(100) ItemStatus char(1) DateCreated smalldatetime Any kind help is highly appreciated.

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• Aptana Open Resource Key Binding

  - by yagudaev

  The default keyboard shortcut for open resource in Eclipse is Ctrl+Shift+R. It is also the case in Aptana, but there also seems to be a conflicting key since when clicked it brings up a context menu with 2 options "Run" and "Open Resource". How to I avoid having this context menu pop up? I tried to go to the preferences and look for conflicting key-bindings but I could not find it. I am also not sure what "Run" command is actually bound (I tried searching based on the key combination, that did not seem to have worked).

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• can ping but cannot browse.Can you help

  - by user231465

  Hi all I have winxp with the latest service pack on my old laptop. I have a situation where I can Ping and status says connected but cannot browse. I have seen various post on the net proposing solutions that works for some and not for others I have tried reseting winsock but nothing. If I vpn to my work then I can browse. I would like to avoid reformatting the computer and not take such a drastic action. Any suggestions?

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• Querying Postgresql with a very large result set

  - by sanity

  In an application I need to query a Postgres DB where I expect tens or even hundreds of millions of rows in the result set. I might do this query once a day, or even more frequently. The query itself is relatively simple, although may involve a few JOINs. My question is: How smart is Postgres with respect to avoiding having to seek around the disk for each row of the result set? Given the time required for a hard disk seek, this could be extremely expensive. If this isn't an issue, how does Postgres avoid it? How does it know how to lay out data on the disk such that it can be streamed out in an efficient manner in response to this query?

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• Bash file descriptor leak

  - by Charles Duffy

  I get a file descriptor leak when running the following code: function get_fd_count() { local fds cd /proc/$$/fd; fds=( * ) # avoid a StackOverflow source colorizer bug echo "${#fds[@]}" } function fd_leak_func() { echo ">> Current FDs: $(get_fd_count)" read retval new_state < <(set +e; new_state=$(echo foo); retval=$?; printf "%d %s\n" $retval $new_state) } function parent_func() { while fd_leak_func; do :; done } parent_func Tested on both 3.2.25 and 4.0.28. Taking the while loop out of parent_func and running it at top level makes the problem go away. What's going on here? More to the point, are workarounds available?

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• Easiest way to keep SSRS child elements in the same relative position when the parent is re-positioned?

  - by Mac

  I am trying to revise the layout of an SSRS report where I have several textboxes that are child elements of a rectangle. When I reposition the parent rectangle down by x, all of the child textboxes maintain the same absolute position. Their "Location" (defined relative to the parent) decreases by x. I then need to reposition the child textboxes. Additionally, if any of these ever has a negative "Location" then the parent rectangle is then repositioned back up by x. What is the easiest way to move everything in unison? I can Control-click everything and then drag them or use the arrow keys, but I want to position everything with precision and the "Location" field in the Properties window disappears when selecting more than one item. Is there a way I can avoid individually computing and typing in every "Location" value every time I have a small layout change? I am using SSRS (11.0.3360.12) within the Visual Studio 2012 Shell. Thanks!

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• facelet - nested <ui:insert>

  - by user321350

  I have multiple templates which differs with each other only by few containers. The most complex one contains superset of all containers used in all other one thus to avoid creating multiple templates I created the most complex one in following format some layout stuff (div and all) defining nested insert for each container and content. Now in client template based on what is needed I turn off container which is not needed as else if container is needed, just define content as doSomething Please let me know if you guys see any issues with this approach, any potential problem or alternate approach for similar scenario. thanks a lot. Maddy

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• this pointer to base class constructor?

  - by Rolle

  I want to implement a derived class that should also implement an interface, that have a function that the base class can call. The following gives a warning as it is not safe to pass a this pointer to the base class constructor: struct IInterface { void FuncToCall() = 0; }; struct Base { Base(IInterface* inter) { m_inter = inter; } void SomeFunc() { inter->FuncToCall(); } IInterface* m_inter; }; struct Derived : Base, IInterface { Derived() : Base(this) {} FuncToCall() {} }; What is the best way around this? I need to supply the interface as an argument to the base constructor, as it is not always the dervied class that is the interface; sometimes it may be a totally different class. I could add a function to the base class, SetInterface(IInterface* inter), but I would like to avoid that.

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• strategy to allocate/free lots of small objects

  - by aaa

  hello I am toying with certain caching algorithm, which is challenging somewhat. Basically, it needs to allocate lots of small objects (double arrays, < 256 elements), with objects accessible through mapped value, map[key] = array. time to initialized array may be quite large, generally more than 10 thousand cpu cycles. By lots I mean around gigabyte in total. objects may need to be popped/pushed as needed, generally in random places, one object at a time. lifetime of an object is generally long, minutes or more, however, object may be subject to allocation/deallocation several times during duration of program. What would be good strategy to avoid memory fragmentation, while still maintaining reasonable allocate deallocate speed? I am using C++, so I can use new and malloc. Thanks. I know there a similar questions on website, http://stackoverflow.com/questions/2156745/efficiently-allocating-many-short-lived-small-objects, are somewhat different, thread safety is not immediate issue for me.

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