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• How to benchmark on multi-core processors

  - by Pascal Cuoq

  I am looking for ways to perform micro-benchmarks on multi-core processors. Context: At about the same time desktop processors introduced out-of-order execution that made performance hard to predict, they, perhaps not coincidentally, also introduced special instructions to get very precise timings. Example of these instructions are rdtsc on x86 and rftb on PowerPC. These instructions gave timings that were more precise than could ever be allowed by a system call, allowed programmers to micro-benchmark their hearts out, for better or for worse. On a yet more modern processor with several cores, some of which sleep some of the time, the counters are not synchronized between cores. We are told that rdtsc is no longer safe to use for benchmarking, but I must have been dozing off when we were explained the alternative solutions. Question: Some systems may save and restore the performance counter and provide an API call to read the proper sum. If you know what this call is for any operating system, please let us know in an answer. Some systems may allow to turn off cores, leaving only one running. I know Mac OS X Leopard does when the right Preference Pane is installed from the Developers Tools. Do you think that this make rdtsc safe to use again? More context: Please assume I know what I am doing when trying to do a micro-benchmark. If you are of the opinion that if an optimization's gains cannot be measured by timing the whole application, it's not worth optimizing, I agree with you, but I cannot time the whole application until the alternative data structure is finished, which will take a long time. In fact, if the micro-benchmark were not promising, I could decide to give up on the implementation now; I need figures to provide in a publication whose deadline I have no control over.

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• How to keep your unit test Arrange step simple and still guarantee DDD invariants ?

  - by ian31

  DDD recommends that the domain objects should be in a valid state at any time. Aggregate roots are responsible for guaranteeing the invariants and Factories for assembling objects with all the required parts so that they are initialized in a valid state. However this seems to complicate the task of creating simple, isolated unit tests a lot. Let's assume we have a BookRepository that contains Books. A Book has : an Author a Category a list of Bookstores you can find the book in These are required attributes : a book has to have an author, a category and at least a book store you can buy the book from. There's likely to be a BookFactory since it is quite a complex object, and the Factory will initialize the Book with at least all the mentioned attributes. Now we want to unit test a method of the BookRepository that returns all the Books. To test if the method returns the books, we have to set up a test context (the Arrange step in AAA terms) where some Books are already in the Repository. If the only tool at our disposal to create Book objects is the Factory, the unit test now also uses and is dependent on the Factory and inderectly on Category, Author and Store since we need those objects to build up a Book and then place it in the test context. Would you consider this is a dependency in the same way that in a Service unit test we would be dependent on, say, a Repository that the Service would call ? How would you solve the problem of having to re-create a whole cluster of objects in order to be able to test a simple thing ? How would you break that dependency and get rid of all these attributes we don't need in our test ? By using mocks or stubs ? If you mock up things a Repository contains, what kind of mock/stubs would you use as opposed to when you mock up something the object under test talks to or consumes ?

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• Connecting an overloaded PyQT signal using new-style syntax

  - by Claudio

  I am designing a custom widget which is basically a QGroupBox holding a configurable number of QCheckBox buttons, where each one of them should control a particular bit in a bitmask represented by a QBitArray. In order to do that, I added the QCheckBox instances to a QButtonGroup, with each button given an integer ID: def populate(self, num_bits, parent = None): """ Adds check boxes to the GroupBox according to the bitmask size """ self.bitArray.resize(num_bits) layout = QHBoxLayout() for i in range(num_bits): cb = QCheckBox() cb.setText(QString.number(i)) self.buttonGroup.addButton(cb, i) layout.addWidget(cb) self.setLayout(layout) Then, each time a user would click on a checkbox contained in self.buttonGroup, I'd like self.bitArray to be notified so I can set/unset the corresponding bit in the array. For that I intended to connect QButtonGroup's buttonClicked(int) signal to QBitArray's toggleBit(int) method and, to be as pythonic as possible, I wanted to use new-style signals syntax, so I tried this: self.buttonGroup.buttonClicked.connect(self.bitArray.toggleBit) The problem is that buttonClicked is an overloaded signal, so there is also the buttonClicked(QAbstractButton*) signature. In fact, when the program is executing I get this error when I click a check box: The debugged program raised the exception unhandled TypeError "QBitArray.toggleBit(int): argument 1 has unexpected type 'QCheckBox'" which clearly shows the toggleBit method received the buttonClicked(QAbstractButton*) signal instead of the buttonClicked(int) one. So, the question is, how can we specify, using new-style syntax, that self.buttonGroup emits the buttonClicked(int) signal instead of the default overload - buttonClicked(QAbstractButton*)?

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• Refactoring exercise with generics

  - by Berryl

  I have a variation on a Quantity (Fowler) class that is designed to facilitate conversion between units. The type is declared as: public class QuantityConvertibleUnits<TFactory> where TFactory : ConvertableUnitFactory, new() { ... } In order to do math operations between dissimilar units, I convert the right hand side of the operation to the equivalent Quantity of whatever unit the left hand side is in, and do the math on the amount (which is a double) before creating a new Quantity. Inside the generic Quantity class, I have the following: protected static TQuantity _Add<TQuantity>(TQuantity lhs, TQuantity rhs) where TQuantity : QuantityConvertibleUnits<TFactory>, new() { var toUnit = lhs.ConvertableUnit; var equivalentRhs = _Convert<TQuantity>(rhs.Quantity, toUnit); var newAmount = lhs.Quantity.Amount + equivalentRhs.Quantity.Amount; return _Convert<TQuantity>(new Quantity(newAmount, toUnit.Unit), toUnit); } protected static TQuantity _Subtract<TQuantity>(TQuantity lhs, TQuantity rhs) where TQuantity : QuantityConvertibleUnits<TFactory>, new() { var toUnit = lhs.ConvertableUnit; var equivalentRhs = _Convert<TQuantity>(rhs.Quantity, toUnit); var newAmount = lhs.Quantity.Amount - equivalentRhs.Quantity.Amount; return _Convert<TQuantity>(new Quantity(newAmount, toUnit.Unit), toUnit); } ... same for multiply and also divide I need to get the typing right for a concrete Quantity, so an example of an add op looks like: public static ImperialLengthQuantity operator +(ImperialLengthQuantity lhs, ImperialLengthQuantity rhs) { return _Add(lhs, rhs); } The question is those verbose methods in the Quantity class. The only change between the code is the math operator (+, -, *, etc.) so it seems that there should be a way to refactor them into a common method, but I am just not seeing it. How can I refactor that code? Cheers, Berryl

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• Working with complex objects in Prevayler commands

  - by alexantd

  The demos included in the Prevayler distribution show how to pass in a couple strings (or something simple like that) into a command constructor in order to create or update an object. The problem is that I have an object called MyObject that has a lot of fields. If I had to pass all of them into the CreateMyObject command manually, it would be a pain. So an alternative I thought of is to pass my business object itself into the command, but to hang onto a clone of it (keeping in mind that I can't store the BO directly in the command). Of course after executing this command, I would need to make sure to dispose of the original copy that I passed in. public class CreateMyObject implements TransactionWithQuery { private MyObject object; public CreateMyObject(MyObject business_obj) { this.object = (MyObject) business_obj.clone(); } public Object executeAndQuery(...) throws Exception { ... } } The Prevayler wiki says: Transactions can't carry direct object references (pointers) to business objects. This has become known as the baptism problem because it's a common beginner pitfall. Direct object references don't work because once a transaction has been serialized to the journal and then deserialized for execution its object references no longer refer to the intended objects - - any objects they may have referred to at first will have been copied by the serialization process! Therefore, a transaction must carry some kind of string or numeric identifiers for any objects it wants to refer to, and it must look up the objects when it is executed. I think by cloning the passed-in object I will be getting around the "direct object pointer" problem, but I still don't know whether or not this is a good idea...

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• Analyze log files from many languages using a single tool. And recommendations of logging frameworks

  - by Binary255

  We have a system build on lots of languages. The ones we are interested in logging, in order of priority, are: C/C++ PHP C# Bash Java Wish list: If it is possible, we would like logging to be achieved from the above languages in such a way that we may use a single log viewing tool for all of them. Ideally they would be in the same format, but next to that in as few formats as possible and readable from as many log file viewers as possible. If it is possible logging to a single log file or a set of log files would be nice. With a possibility to filter based on the source language that is being logged. We would like to copy the log files (or should be log to a database and copy it instead?) from multiple servers to a single location. So that we can analyze the log files from many servers at the same time (to see if any of our servers execute a certain piece legacy code for example). Being able to change logging level at runtime would be nice. Thank you for reading! It's quite a complex problem, I hope someone has wrestled with it before and has some valuable information!

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• Ajax UpdatePanels SetFocus issue

  - by George

  I set the AutoPostback property of a textbox to True so I can process the TextChanged event on the server and, based on what they typed in the textbox, appropriately display a message in an update panel. The problem is, when the partial screen refresh is performed, no control on the screen has focus. 99% of the time, when the text in the textbox is changed, it is because the user has tabbed forward, and so, to limit the disruption in the lost of focus, I perform a "Focus" call on teh next control in the tab sequence. For the most part, this works OK, but of course, is disputive if the user is tabbing in the reverse order or has used the mouse to set the focus to another control. In these situations, the focus would be set to the next control even though the user was trying to set focus elsewhere. OK, that sucks. Now what I consider the bigger problem with calling the focus method on the server: In IE, it works OK, but in Mozilla Firefox and Chrome, setting the focus causes a repositioning of the scroll bar, even though none is necessary because the control is already in view. I realize that I could switch to doing AJAX web service calls, but these darn Updae Panels are so convenient if used in moderation. is there anyway to use updatepanels and not have these focus/scroll issues?

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• Inner join on 2 arrays?

  - by russ

  I'm trying to find a solution to the following (I'm thinking with Linq) to the following: I need to pull down certain files from a larger list of files on an ftp server that have a similar file name. For example, we send an order file to some company for processing then they return a response file that we can download. So, I could send them the files "order_123.txt" and "order_456.txt". After a certain amount of time I need to go look for and download the responses for those files that will be named "order_123.resp" and "order_456.resp". The kicker is that in some cases I can have multiple responses in which case they would create "order_123-1.resp" and "order_123-2.resp" and also the files don't get removed from the server. I know this can be accomplished by looping through the files I know I need responses to then loop through all the files on the server until I find files that match but I'm hoping that I don't have to loop through the files on the server more than once. This example may help clarify: I've sent "order_222.txt" and "order_333.txt" they processed them and the ftp server contains: "order_111-1.resp" "order_001.resp" "order_222-1.resp" "order_222-2.resp" "order_333.resp" I need to download the 3rd, 4th, and 5th file. Thanks.

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• Targetting x86 vs AnyCPU when building for 64 bit window OSes

  - by Mr Roys

  I have an existing C# application written for .NET 2.0 and targetting AnyCPU at the moment. It currently references some third party .NET DLLs which I don't have the source for (and I'm not sure if they were built for x86, x64 or AnyCPU). If I want to run my application specifically on a 64 bit Windows OS, which platform should I target in order for my app to run without errors? My understanding at the moment is to target: x86: If at least one third party .NET dll is built for x86 or use p/Invoke to interface with Win32 DLLs. Application will run in 32 bit mode on both 32 bit and 64 bit OSes. x64: If all third party .NET dlls are already built for x64 or AnyCPU. Application will only run in 64 bit OSes. AnyCPU: If all third party .NET dlls are already built for AnyCPU. Application will run in 32 bit mode on 32 bit OSes and 64 bit on 64 bit OSes. Also, am I right to believe that while targetting AnyCPU will generate no errors when building a application referencing third party x86 .NET DLLs, the application will throw a runtime exception when it tries to load these DLLs when it runs on a 64 bit OS. Hence, as long as one of my third party DLLs is doing p/Invoke or are x86, I can only target x86 for this application?

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• Why do bind1st and bind2nd require constant function objects?

  - by rlbond

  So, I was writing a C++ program which would allow me to take control of the entire world. I was all done writing the final translation unit, but I got an error: error C3848: expression having type 'const `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>' would lose some const-volatile qualifiers in order to call 'void `anonymous-namespace'::ElementAccumulator<T,BinaryFunction>::operator ()(const point::Point &,const int &)' with [ T=SideCounter, BinaryFunction=std::plus<int> ] c:\program files (x86)\microsoft visual studio 9.0\vc\include\functional(324) : while compiling class template member function 'void std::binder2nd<_Fn2>::operator ()(point::Point &) const' with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] c:\users\****\documents\visual studio 2008\projects\TAKE_OVER_THE_WORLD\grid_divider.cpp(361) : see reference to class template instantiation 'std::binder2nd<_Fn2>' being compiled with [ _Fn2=`anonymous-namespace'::ElementAccumulator<SideCounter,std::plus<int>> ] I looked in the specifications of binder2nd and there it was: it took a const AdaptibleBinaryFunction. So, not a big deal, I thought. I just used boost::bind instead, right? Wrong! Now my take-over-the-world program takes too long to compile (bind is used inside a template which is instantiated quite a lot)! At this rate, my nemesis is going to take over the world first! I can't let that happen -- he uses Java! So can someone tell me why this design decision was made? It seems like an odd decision. I guess I'll have to make some of the elements of my class mutable for now...

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• Files under Program Files have a split personality

  - by regularfry

  I have a Ruby application I'm installing (along with a packaged ruby interpreter) under Program Files on Windows 7 with an NSIS-built installer. In order to debug it, I edited one of the files to add some debugging statements. After that, I uninstalled the package and ran a new version of the installer which includes a new copy of the edited file, without debugging statements. Now, I can't get the new copy to load into ruby. If I run type <filename> in cmd.exe, or open the file in Notepad.exe or Firefox, I see the new version. If I run ruby -e "puts File.read('<filename>')", or open the file in emacs, I see the old version. If, in Windows Explorer, I copy the file to a new filename, everything can see the new contents at that filename. If I delete the original file and rename the copy to replace the original, the split personality returns. This situation survives a reboot, so it's not a simple matter of a file being accidentally held open. What on earth is going on here? Is there some aspect of the install process that might be checkpointing the file in a way I can revert, or at least switch off while I'm debugging the installer?

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• How can I get the user object from a service in Symfony2

  - by pogo

  My site is using a third party service for authentication as well as other bits of functionality so I have setup a service that does all the API calls for me and it's this service that I need to be able to access the user object. I've tried injecting the security.context service into my API service but I get a ServiceCircularReferenceException because my user authentication provider references the API service (it has to in order to authenticate the user). So I get a chain of security.context -> authentication provider -> user provider -> API service -> security.context I'm struggling to this of another way of getting the user object and I can't see any obvious way of splitting up this chain. My configs are all defined in config.yml, here are the relevant bits myapp.database: class: Pogo\MyAppBundle\Service\DatabaseService arguments: siteid: %siteid% entityManager: "@doctrine.orm.entity_manager" myapp.apiservice: class: Pogo\MyAppBundle\Service\TicketingService arguments: entityManager: "@myapp.database" myapp.user_provider: class: Pogo\MyAppBundle\Service\APIUserProvider arguments: entityManager: "@myapp.database" ticketingAdapter: "@myapp.apiservice" securityContext: "@security.context" myapp.authenticationprovider: class: Pogo\MyAppBundle\Service\APIAuthenticationProvider arguments: userChecker: "@security.user_checker" encoderFactory: "@security.encoder_factory" userProvider: "@myapp.user_provider" myapp.user_provider is the service that I've defined as my user provider service in security.yml which I presume is how it's being referenced by security.context

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• How does mercurial's bisect work when the range includes branching?

  - by Joshua Goldberg

  If the bisect range includes multiple branches, how does hg bisect's search work. Does it effectively bisect each sub-branch (I would think that would be inefficient)? For instance, borrowing, with gratitude, a diagram from an answer to this related question, what if the bisect got to changeset 7 on the "good" right-side branch first. @ 12:8ae1fff407c8:bad6 | o 11:27edd4ba0a78:bad5 | o 10:312ba3d6eb29:bad4 |\ | o 9:68ae20ea0c02:good33 | | | o 8:916e977fa594:good32 | | | o 7:b9d00094223f:good31 | | o | 6:a7cab1800465:bad3 | | o | 5:a84e45045a29:bad2 | | o | 4:d0a381a67072:bad1 | | o | 3:54349a6276cc:good4 |/ o 2:4588e394e325:good3 | o 1:de79725cb39a:good2 | o 0:2641cc78ce7a:good1 Will it then look only between 7 and 12, missing the real first-bad that we care about? (thus using "dumb" numerical order) or is it smart enough to use the full topography and to know that the first bad could be below 7 on the right-side branch, or could still be anywhere on the left-side branch. The purpose of my question is both (a) just to understand the algorithm better, and (b) to understand whether I can liberally extend my initial bisect range without thinking hard about what branch I go to. I've been in high-branching bisect situations where it kept asking me after every test to extend beyond the next merge, so that the whole procedure was essentially O(n). I'm wondering if I can just throw the first "good" marker way back past some nest of merges without thinking about it much, and whether that would save time and give correct results.

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• jquery-ui autocomplete with ASP MVC suggestions not displaying

  - by adamnickerson

  I have been trying to get a simple example of the jquery-ui autocomplete to work. I have a controller setup to handle the query, and it returns the json that looks to be in order, but I am getting no suggestions showing up. Here are the js libraries I am including: <script type="text/javascript" language="javascript" src="/Scripts/jquery-1.4.1.js"></script> <script type="text/javascript" language="javascript" src="/Scripts/jquery-ui-1.8.1.custom.min.js"></script> <link href="/Content/jquery-ui-1.8.1.custom.css" rel="stylesheet" type="text/css" /> and here is the javascript and the form tags: <script type="text/javascript"> $(function () { $("#organization").autocomplete({ source: function (request, response) { $.ajax({ url: '/Organization/OrganizationLookup', dataType: "json", data: { limit: 12, q: request.term } }) }, minLength: 2 }); }); </script> <div class="ui-widget"> <label for="organization">Organization: </label> <input id="organization" /> </div> I get back a json response that looks reasonable from my controller: [{"id":"Sector A","value":"Sector A"},{"id":"Sector B","value":"Sector B"},{"id":"Sector C","value":"Sector C"}] id and value seem to be the default naming that autocomplete is looking for. But I get no joy at all. Any thoughts?

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• Use LINQ to group a sequence by date with no gaps

  - by Codesleuth

  I'm trying to select a subgroup of a list where items have contiguous dates, e.g. ID StaffID Type Title ActivityDate -- ------- ---- ----------------- ------------ 1 41 1 Doctors 07/06/2010 2 41 0 Meeting with John 08/06/2010 3 41 0 Meeting Continues 09/06/2010 4 41 0 Meeting Continues 10/06/2010 5 41 3 Annual Leave 11/06/2010 6 41 0 Meeting Continues 14/06/2010 I'm using a pivot point each time, so take the example pivot item as 3, I'd like to get the following resulting contiguous events around the pivot: ID StaffID Type Title ActivityDate -- ------- ---- ----------------- ------------ 2 41 0 Meeting with John 08/06/2010 3 41 0 Meeting Continues 09/06/2010 4 41 0 Meeting Continues 10/06/2010 My current implementation is a laborious "walk" into the past, then into the future, to build the list: var orderedEvents = activities.OrderBy(a => a.ActivityDate).ToArray(); // Walk into the past until a gap is found var preceedingEvents = orderedEvents.TakeWhile(a => a.ID != activity.ID); DateTime dayBefore; var previousEvent = activity; while (previousEvent != null) { dayBefore = previousEvent.ActivityDate.AddDays(-1).Date; previousEvent = preceedingEvents.TakeWhile(a => a.ID != previousEvent.ID).LastOrDefault(); if (previousEvent != null) { if (previousEvent.ActivityDate.Date == dayBefore) relatedActivities.Insert(0, previousEvent); else previousEvent = null; } } // Walk into the future until a gap is found var followingEvents = orderedEvents.SkipWhile(a => a.ID != activity.ID); DateTime dayAfter; var nextEvent = activity; while (nextEvent != null) { dayAfter = nextEvent.ActivityDate.AddDays(1).Date; nextEvent = followingEvents.SkipWhile(a => a.ID != nextEvent.ID).Skip(1).FirstOrDefault(); if (nextEvent != null) { if (nextEvent.ActivityDate.Date == dayAfter) relatedActivities.Add(nextEvent); else nextEvent = null; } } The list relatedActivities should then contain the contiguous events, in order. Is there a better way (maybe using LINQ) for this? I had an idea of using .Aggregate() but couldn't think how to get the aggregate to break out when it finds a gap in the sequence.

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• Non-blocking TCP connection issues.

  - by Poni

  Hi! I think I'm in a problem. I have two TCP apps connected to each other which use winsock I/O completion ports to send/receive data (non-blocking sockets). Everything works just fine until there's a data transfer burst. The sender starts sending incorrect/malformed data. I allocate the buffers I'm sending on the stack, and if I understand correctly, that's a wrong to do, because these buffers should remain as I sent them until I get the "write complete" notification from IOCP. Take this for example: void some_function() { char cBuff[1024]; // filling cBuff with some data WSASend(...); // sending cBuff, non-blocking mode // filling cBuff with other data WSASend(...); // again, sending cBuff // ..... and so forth! } If I understand correctly, each of these WSASend() calls should have its own unique buffer, and that buffer can be reused only when the send completes. Correct? Now, what strategies can I implement in order to maintain a big sack of such buffers, how should I handle them etc'? And, if I am to use buffers that means I should copy the data to be sent from the source buffer to the temporary one, thus, I'd set SO_SNDBUF on each socket to zero, so the system will not re-copy what I already copied. Are you with me? Please let me know if I wasn't clear.

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• Modifying existing object attributes in Core Data after the fact

  - by glorifiedHacker

  In a previous question, I was looking for an alternative to modifying how "no date" was being stored in the date attribute of my NSManagedObject subclass. Previously, I had assigned nil to that attribute when a user didn't assign a date. In order to address sorting issues when using NSFetchedResultsController, I have decided to assign [NSDate distantFuture] to the date attribute when a user doesn't assign a date. However, given that this app is already in the wild, I need to update the Core Data store such that any existing nil date values are changed to [NSDate distantFuture]. What is the best way to make this change? The first thing that comes to mind is to iterate through all of the objects in the store in an array and change any nil values that are found. This could be limited to a one-time event by checking against a user defaults key that indicates whether this upgrade has been performed. Is there a way that I can do this with Core Data versioning instead? Or another method that doesn't involve me writing throw-away code?

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• Eclipselink: Create objects from JOIN query

  - by Raven

  Hi, I have a SQL query SELECT * FROM Thing AS a JOIN Thing_Property AS b ON a.id=b.Thing_ID JOIN Property AS c ON b.properties_ID = c.id JOIN Item AS d ON c.item_ID = d.id ORDER BY a.name, d.name and I Eclipselink to create my object model with it. Here is the model: @SuppressWarnings("serial") @Entity public class Thing implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; @OneToMany(cascade=CascadeType.ALL) @PrivateOwned private List<Property> properties = new ArrayList<Property>(); ... // getter and setter following here } public class Property implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; @OneToOne private Item item; private String value; ... // getter and setter following here } public class Item implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; .... // getter and setter following here } // Code end but I can not figure out, how to make Eclipselink create the model from that query. Can you help?

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• What would be the light way to render a JSP page without an App/Web Server

  - by kolrie

  First, some background: I will have to work on code for a JSP that will demand a lot of code fixing and testing. This JSP will receive a structure of given objects, and render it according to a couple of rules. What I would like to do, is to write a "Test Server" that would read some mock data out of a fixtures file, and mock those objects into a factory that would be used by the JSP in question. The target App Server is WebSphere and I would like to code, change, code in order to test appropriate HTML rendering. I have done something similar on the past, but the JSP part was just calling a method on a rendering object, so I created an Ad Hoc HTTP server that would read the fixture files, parse it and render HTML. All I had to do was run it inside RAD, change the HTML code and hit F5. So question pretty much goes down to: Is there any stand alone library or lightweight server (I thought of Jetty) that would take a JSP, and given the correct contexts (Request, Response, Session, etc.) render the proper HTML?

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• Can shared memory be read and validated without mutexes?

  - by Bribles

  On Linux I'm using shmget and shmat to setup a shared memory segment that one process will write to and one or more processes will read from. The data that is being shared is a few megabytes in size and when updated is completely rewritten; it's never partially updated. I have my shared memory segment laid out as follows: ------------------------- | t0 | actual data | t1 | ------------------------- where t0 and t1 are copies of the time when the writer began its update (with enough precision such that successive updates are guaranteed to have differing times). The writer first writes to t1, then copies in the data, then writes to t0. The reader on the other hand reads t0, then the data, then t1. If the reader gets the same value for t0 and t1 then it considers the data consistent and valid, if not, it tries again. Does this procedure ensure that if the reader thinks the data is valid then it actually is? Do I need to worry about out-of-order execution (OOE)? If so, would the reader using memcpy to get the entire shared memory segment overcome the OOE issues on the reader side? (This assumes that memcpy performs it's copy linearly and ascending through the address space. Is that assumption valid?)

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• Attachment empty/blank when sending mail using phpmailer

  - by chupinette

  Hello! I am using phpmailer class to send email and i am attaching a file to the mail. The email is sent successfully but the attachment which is an sql file is empty which should not be the case. I have tried with an image file, but it seems that every file that i attach is empty. Can anyone help me solve this problem please? $mail = new PHPMailer(); $body = "Reminder"; $mail->IsSMTP(); $mail->Host = "mail.yourdomain.com"; $mail->SMTPDebug = 1; $mail->SMTPAuth = true; $mail->SMTPSecure = "ssl"; $mail->Host = "smtp.gmail.com"; $mail->Port = 465; $mail->Username = "[email protected]"; $mail->Password = "abc"; $mail->SetFrom('[email protected]', 'blbla'); $mail->AddReplyTo("[email protected]","First Last"); $mail->Subject = "Your order has been successfully placed" $mail->MsgHTML($body); $mail->AddAddress("[email protected]","xyz"); $mail->AddAttachment("D:\b2\shop3.sql","shop3.sql"); I have tried to display the size of the file before attaching it, and it actually displays the file size. Can anyone help me please?

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• Loading Jscript files into Firefox extension

  - by colon3l

  Hi ! Let's get directly to the problem : I'm actually doing a firefox extension in which i would like to implement the jWebsocket API in order to build a small chat. I got my main script file, named test.js, and the jWebsocket lib into a js folder. Just for you to know, this is my first firefox extension ever. So in my XUL file I got this (for the script part only of course, the interface code is not shown) : <overlay id="test-overlay" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"> <script type="application/x-javascript" src="chrome://test/content/test.js" /> <script type="application/x-javascript" src="chrome://test/content/js/jwebsocket.js" /> jwebsocket.js being the file I need to call according to jWebsocket website. In my main script file test.js I start with : if (jws.browserSupportsWebSockets()) { jWebSocketClient = new jws.jWebSocketJSONClient(); } else { var lMsg = jws.MSG_WS_NOT_SUPPORTED; alert(lMsg); } jws being the namespace created into the jwebsocket.js file. Of course I've got the required stand-alone server running in background, and working. So from what I understood looking on various websites, is that if a js file is loaded into the javascript allocated memory space (with the tag), all namespace/function should be available between each file. But this was mostly for HTML-oriented issues, so I'm not sure if it applies to XUL/Firefox environment. But the script keep failing at the first jws call. Any ideas on what goes wrong here ? I'm stuck for 2 days now :/

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• Java: How to workaround the lack of Equatable interface?

  - by java.is.for.desktop

  Hello, everyone! As far as I know, things such as SortedMap or SortedSet, use compareTo (rather than equals) on Comparable<?> types for checking equality (contains, containsKey). But what if certain types are equatable by concept, but not comparable? I have to declare a Comparator<?> and override the method int compareTo(T o1, To2). OK, I can return 0 for instances which are considered equal. But, for unqeual instances, what do I return when an order is not evident? Is the approach of using SortedMap or SortedSet on equatable but (by concept) not comparable types good anyway? Thank you! EDIT: I don't want to store things sorted, but would I use "usual" Map and Set, I couldn't "override" the equality-behavior. EDIT 2: Why I can't just override equals(...): I need to alter the equality-behavior of a foreign class. Can't edit it. EDIT 3: Just think of .NET: They have IEquatable interface which cat alter the equality-behavior without touching the comparable behavior.

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• jQuery - select onchange to slide in / slide out div or form

  - by slayaz

  Hi, I am trying to enhance a form, by showing only relevant fields depending on initial selection via a form select field. It is an order form for 3 products and all 3 products have unique properties. My idea was to hide all the content in divs, then reveal the relevant div when the product is selected. I have found some solutions that show / hide a div, but none with any animation. It doesn't have to be a slide but just something nice! The alternative is instead of revealing a div, would be to load a seperate form, but this seems unnecessary. I am not sure whether i need a plug in, as I am pretty new to jquery. What i have in the html is: <style type="text/css"> .hide { display:none; } <select> <option value="" >Please select product below</option> <option value="pro1">Product 1</option> <option value="pro2">Product 2</option> </select> <div id="pro1" class="hide" >Product 1</div> <div id="pro2" class="hide" >Product 2</div> Many thanks in advance

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• Wordpress: How to override all default theme CSS so your custom one is loaded the last?

  - by mickael

  I have a problem where I've been able to include a custom css in the section of my wordpress theme with the following code: function load_my_style_wp_enqueue_scripts() { wp_register_style('my_styles_css', includes_url("/css/my_styles.css")); wp_enqueue_style('my_styles_css'); } add_action('wp_enqueue_scripts','load_my_style_wp_enqueue_scripts'); But the order in the source code is as follows: <link rel='stylesheet' id='my_styles_css-css' href='http://...folderA.../my_styles.css?ver=3.1' type='text/css' media='all' /> <link rel="stylesheet" id="default-css" href="http://...folderB.../default.css" type="text/css" media="screen,projection" /> <link rel="stylesheet" id="user-css" href="http://...folderC.../user.css" type="text/css" media="screen,projection" /> I want my_styles_css to be the last file to load, overriding default and user files. I've tried to achieve this by modifying wp_enqueue_style in different ways, but without any success. I've tried: wp_enqueue_style('my_styles_css', array('default','user')); or wp_enqueue_style('my_styles_css', false, array('default','user'), '1.0', 'all'); I've seen some related questions without answer or with these last 2 methods that are still failing for me. The function above is part of a plugin that I've got enabled in my wordpress installation.

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