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  • proper use of volatile keyword

    - by luke
    I think i have a pretty good idea about the volatile keyword in java, but i'm thinking about re-factoring some code and i thought it would be a good idea to use it. i have a class that is basically working as a DB Cache. it holds a bunch of objects that it has read from a database, serves requests for those objects, and then occasionally refreshes the database (based on a timeout). Heres the skeleton public class Cache { private HashMap mappings =....; private long last_update_time; private void loadMappingsFromDB() { //.... } private void checkLoad() { if(System.currentTimeMillis() - last_update_time > TIMEOUT) loadMappingsFromDB(); } public Data get(ID id) { checkLoad(); //.. look it up } } So the concern is that loadMappingsFromDB could be a high latency operation and thats not acceptable, So initially i thought that i could spin up a thread on cache startup and then just have it sleep and then update the cache in the background. But then i would need to synchronize my class (or the map). and then i would just be trading an occasional big pause for making every cache access slower. Then i thought why not use volatile i could define the map reference as volatile private volatile HashMap mappings =....; and then in get (or anywhere else that uses the mappings variable) i would just make a local copy of the reference: public Data get(ID id) { HashMap local = mappings; //.. look it up using local } and then the background thread would just load into a temp table and then swap the references in the class HashMap tmp; //load tmp from DB mappings = tmp;//swap variables forcing write barrier Does this approach make sense? and is it actually thread-safe?

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  • Having an issue with org.hibernate.SessionException: Session is closed! in Hibernate

    - by hal10001
    I've done quite a bit a research on this with no luck, but all the answers have a tendency to point toward the session context settings in the config file. What is odd is that I get a session connection the very first time I hit the page (and therefore, a successful result set), but then when I reload I get the following exception: org.hibernate.SessionException: Session is closed! Here are my config settings that are not DB connection string related: <property name="hibernate.show_sql">false</property> <property name="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</property> <property name="hibernate.current_session_context_class">thread</property> <property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property> <property name="hibernate.cache.use_query_cache">false</property> <property name="hibernate.cache.use_minimal_puts">false</property> Here is an example of a call I make that produces the situation I described above. public T get(int id) { session.beginTransaction(); T type; try { type = getTypeClass().cast(session.get(getTypeClass(), id)); } catch (ClassCastException classCastException) { throw new ClassCastException(classCastException.getMessage()); } session.getTransaction().commit(); return type; } The session variable reference is to a static field that contains the current session. All of the session connection details are textbook reference manual. For example, here is my Hibernate session utility: import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class HibernateSessionFactoryUtil { private static final SessionFactory sessionFactory = buildSessionFactory(); private static SessionFactory buildSessionFactory() { try { return new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { System.err.println("Initial SessionFactory creation failed." + ex); throw new ExceptionInInitializerError(ex); } } public static SessionFactory getSessionFactory() { return sessionFactory; } }

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  • How to suppress error message details to general DNN Users

    - by thames
    I have a DNN site (05.02.03) in test and nearing release into production and I would like to suppress the details of error messages (i.e. Null Reference Exception, and others) to general users (admins can still see the details). Debug is off in the web.config. By suppressing, I mean the only error message I want to display to the general user (all users) is something like "An Exception has occured". I don't want the details of that exception to be displayed to the general user. I still want it logged in greater detail in the Event Viewer. How would I go about doing this? Update: I have "Use Custom Error Messages" checked. Which shows a error message like: A critical error has occurred.[vbCrLf] Object reference not set to an instance of an object. I want just the "A critical error has occured." error message to be displayed to general users. I don't want the "Object referece not set to an instance of an object." to be displayed to general users

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  • Oracle output: cursor, file, or very long string?

    - by Klay
    First, the setup: I have a table in an Oracle10g database with spatial columns. I need to be able to pass in a spatial reference so that I can reproject the geometry into an arbitrary coordinate system. Ultimately, I need to compress the results of this projection to a zip file and make it available for download through a Silverlight project. I would really appreciate ideas as to the best way to accomplish this. In the examples below, the SRID is the Spatial reference ID integer used to convert the geometric points into a new coordinate system. In particular, I can see a couple of possibilities. There are many more, but this is an idea of how I'm thinking: a) Pass SRID to a dynamic view -- perform projection, output a cursor -- send cursor to UTL_COMPRESS -- write output to a file (somehow) -- send URL to Silverlight app b) Use SRID to call Oracle function from Silverlight app -- perform projection, output a string -- build strings into a file -- compress file using SharpZipLib library in .NET -- send bytestream back to Silverlight app I've done the first two steps of b), and the conversion of 100 points took about 7 seconds, which is unacceptably slow. I'm hoping it would be faster doing the processing totally in Oracle. If anyone can see potential problems with either way of doing this, or can suggest a better way, it would be very helpful. Thanks!

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  • Adding a Taxonomy Filter to a Custom Post Type

    - by ken
    There is an amazing conversation from about two years ago on the Wordpress Answer site where a number of people came up with good solutions for adding a taxonomy filter to the admin screen for your custom post types (see URL for screen I'm referring to): http://[yoursite.com]/wp-admin/edit.php?s&post_status=all&post_type=[post-type] Anyway, I loved Michael's awesome contribution but in the end used Somatic's implementation with the hierarchy option from Manny. I wrapped it in a class - cuz that's how I like to do things -- and it ALMOST works. The dropdown appears but the values in the dropdown are all looking in the $_GET property for the taxonomies slug-name that you are filtering by. For some reason I don't get anything. I looked at the HTML of the dropdown and it appears ok to me. Here's a quick screen shot for some context: You can tell from this that my post-type is called "exercise" and that the Taxonomy I'm trying to use as a filter is "actions". Here then is the HTML surrounding the dropdown list: <select name="actions" id="actions" class="postform"> <option value="">Show all Actions</option> <option value="ate-dinner">Ate dinner(1)</option> <option value="went-running">Went running(1)</option> </select> I have also confirmed that all of the form elements are within the part of the DOM. And yet if I choose "Went running" and click on the filter button the URL query string comes back without ANY reference to what i've picked. More explicitly, the page first loads with the following URL: /wp-admin/edit.php?post_type=exercise and after pressing the filter button while having picked "Went Running" as an option from the actions filter: /wp-admin/edit.php?s&post_status=all&post_type=exercise&action=-1&m=0&actions&paged=1&mode=list&action2=-1 actually you can see a reference to an "actions" variable but it's set to nothing and as I now look in detail it appears that the moment I hit "filter" on the page it resets the filter dropdown to the default "Show All Actions". Can anyone help me with this?

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  • Object Oriented Programming in AS3

    - by Jordan
    I'm building a game in as3 that has balls moving and bouncing off the walls. When the user clicks an explosion appears and any ball that hits that explosion explodes too. Any ball that then hits that explosion explodes and so on. My question is what would be the best class structure for the balls. I have a level system to control levels and such and I've already come up with working ways to code the balls. Here's what I've done. My first attempt was to create a class for Movement, Bounce, Explosion and finally Orb. These all extended each other in the order I just named them. I got it working but having Bounce extend Movement and Explosion extend Bounce, it just doesn't seem very object oriented because what if I wanted to add a box class that didn't move, but did explode? I would need a separate class for that explosion. My second attempt was to create Movement, Bounce and Explosion without extending anything. Instead I passed in a reference to the Orb class to each. Then the class stores that reference and does what it needs to do based on events that are dispatched by the Orb such as update, which was broadcast from Orb every enter frame. This would drive the movement and bounce and also the explosion when the time came. This attempt worked as well but it just doesn't seem right. I've also thought about using Interfaces but because they are more of an outline for classes, I feel like code reuse goes out the window as each class would need its own code for a specific task even if that task is exactly the same. I feel as if I'm searching for some form of multiple inheritance for classes that as3 does not support. Can someone explain to me a better way of doing what I'm attempting to do? Am I being to "Object Oriented" by having classed for Movement, Bounce, Explosion and Orb? Are Interfaces the way to go? Any feedback is appreciated!

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  • Apache Tuscany 1.6 How do you set the JMS Binding Delivery Mode to NON_PERSISTENT?

    - by Robert Greiner
    I am using Tuscany 1.6 and am trying to set the Delivery Mode JMS Binding to NON_PERSISTENT. I've tried using uri="jms:MyService?deliveryMode=1" (which is what the spec (PDF) says to do) but, I ended up getting the following exception: Unknown token deliveryMode=1 I also tried <headers JMSDeliveryMode="NON_PERSISTENT"/>, although I did not get an exception the messages still got delivered as PERSISTENT. This is the format for the URI jms:<jms-dest>? connectionFactoryName=<Connection-Factory-Name> & destinationType={queue|topic} deliveryMode=<Delivery-Mode> & timeToLive=<Time-To-Live> & priority=<Priority> & <User-Property>=<User-Property-Value> & … This is the example I am using <composite xmlns="http://www.osoa.org/xmlns/sca/1.0" name="MyValueComposite"> <service name="MyValueService"> <interface.java interface="services.myvalue.MyValueService"/> <binding.jms uri="jms:MyValueServiceQueue?activationSpecName=MyValueServiceAS&... "/> </service> <reference name="StockQuoteService"> <interface.java interface="services.stockquote.StockQuoteService"/> <binding.jms uri="jms:StockQuoteServiceQueue?connectionFactoryName=StockQuoteServiceQCF&deliveryMode=1&... "/> </reference> </composite>

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  • How do I get XML path by its value?

    - by user299938
    I need to get the xml path opf the xml file by providing the value of an xml child element as the input. For example: XML file: <?xml version="1.0"?> <document-inquiry xmlns="http://ops.epo.org"> <publication-reference data-format="docdb" xmlns="http://www.epo.org/exchange"> <document-id> <country>EP</country> <doc-number>1000</doc-number> <kind>A1</kind> </document-id> </publication-reference> </document-inquiry> For the above XML file. I need to get the XML path by using the value "1000". If my input is value of the element "1000" Output i need is : <document-id> <country>EP</country> <doc-number>1000</doc-number> <kind>A1</kind> </document-id> I need to achieve this using c# code. Can anyone please help me out on this...

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  • Delphi App has "No Debug Info" when Debugging

    - by James L.
    We have built an application that uses packages and components. When we debug the application, the "Event Log" in the IDE often shows the our BPLs are being loaded without debug information ("No Debug Info"). This doesn't make sense because all our packages and EXEs are built with debug. _(each project) | Options | Compiling_ [ x ] Assertions [ x ] Debug information [ x ] Local symbols Symbol reference info = "Reference info" [ ] Use debug .dcus [ x ] Use imported data references _(each project) | Options | Linking_ [ x ] Debug information Map file = Detailed We have 4 projects, all built with runtime pacakges: Core.bpl Components.bpl Plugin.bpl (uses both #1 & #2) MainApp.exe (uses #1) Problems Observed 1) Many times when we debug, the Components.bpl is loaded with debug info, but all values in the "Local Variables" window are blank. If you hover your mouse over a variable in the code, there is no popup, and Evaluate window also shows nothing (the "Result" pane is always blank). 2) Sometimes the Event Log shows "No Debug Info" for various BPLs. For instance, if we activate the Plugin.bpl project and set it's Run | Parameter's Host Application to be the MainApp.exe, and then press F9, all modules seems to load with "Has Debug Info" except for the Plugin.bpl module. When it loads, the Event Log shows "No Debug Info". However, if we close the app and immediately press F9, it will run it again without recompiling anything and this time Plugin.bpl is loaded with debug ("Has Debug Info"). Questions 1) What would cause the "Local Variables" window to not display the values? 2) Why are BPLs sometimes loaded without debug info when the BPL was complied with debug and all the debug files (dcu, map, etc.) are available?

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  • linearRGB conversion to/from HSL

    - by Otaku
    Does anyone know of a way to get HSL from an linearRGB color (not an sRGB color)? I've seen a lot of sRGB<-HSL conversions, but nothing for linearRGB<-HSL. Not sure if it is fundementally the same conversion with minor tweaks, but I'd appreciate any insight someone may have on this. Linear RGB is not the same as linearizing sRGB (which is taking [0,255] and making it [0,1]). Linear RGB transformation from/to sRGB is at http://en.wikipedia.org/wiki/SRGB. In VBA, this would be expressed (taking in linearized sRGB values [0,1]): Public Function sRGB_to_linearRGB(value As Double) If value < 0# Then sRGB_to_linearRGB = 0# Exit Function End If If value <= 0.04045 Then sRGB_to_linearRGB = value / 12.92 Exit Function End If If value <= 1# Then sRGB_to_linearRGB = ((value + 0.055) / 1.055) ^ 2.4 Exit Function End If sRGB_to_linearRGB = 1# End Function Public Function linearRGB_to_sRGB(value As Double) If value < 0# Then linearRGB_to_sRGB = 0# Exit Function End If If value <= 0.0031308 Then linearRGB_to_sRGB = value * 12.92 Exit Function End If If value < 1# Then linearRGB_to_sRGB = 1.055 * (value ^ (1# / 2.4)) - 0.055 Exit Function End If linearRGB_to_sRGB = 1# End Function I have tried sending in Linear RGB values to standard RGB_to_HSL routines and back out from HSL_to_RGB, but it does not work. I have seen almost no references that this can be done, except for two: A reference on http://en.wikipedia.org/wiki/HSL_and_HSV#cite_note-9 (numbered item 10). A reference on an open source project Grafx2 @ http://code.google.com/p/grafx2/issues/detail?id=63#c22 in which the contributor states that he has done Linear RGB <- HSL conversion and provides some C code in an attachment to his comment in a .diff file (which I can't really read :( ) My intent is to send from sRGB (for example, FF99FF (R=255, G=153, B=255)) to Linear RGB (R=1.0, G=0.318546778125092, B=1.0) using the code above (for example, the G=153 would be obtained in Linear RGB from sRGB_to_linearRGB(153 / 255)) to HSL, modify the Saturation by 350% and going back from HSL-Linear RGB-sRGB, the result would be FF19FF (R=255, G=25, B=255). Using available functions from .NET, such as .getHue from a System.Drawing.Color does not work in any sRGB space above 100% modulation of any HSL value, hence the need for Linear RGB to be sent in instead of sRGB.

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  • Code Organization Connundrum: Web Project With Multiple Supporting DLLs?

    - by Code Sherpa
    Hi. I am trying to get a handle on the best practice for code organization within my project. I have looked around on the internet for good examples and, so far, I have seen examples of a web project with one or multiple supporting class libraries that it references or a web project with sub-folders that follow its namespace conventions. Assuming there is no right answer, this is what I currently have for code organization: MyProjectWeb This is my web site. I am referencing my class libraries here. MyProject.DLL As the base namespace, I am using this DLL for files that need to be generally consumable. For example, my class "Enums" that has all the enumerations in my project lives there. As does class MyProjectException for all exception handling. MyProject.IO.DLL This is a grouping of maybe 20 files that handle file upload and download (so far). MyProject.Utilities.DLL ALl my common classes and methods bunched up together in one generally consumable DLL. Each class follows a "XHelper" convention such as "SqlHelper, AuthHelper, SerializationHelper, and so on... MyProject.Web.DLL I am using this DLL as the main client interface. Right now, the majority of class files here are: 1) properties (such as School, Location, Account, Posts) 2) authorization stuff ( such as custom membership, custom role, & custom profile providers) My question is simply - does this seem logical? Also, how do I avoid having to cross reference DLLs from one project library to the next? For example, MyProject.Web.DLL uses code from MyProject.Utilities.DLL and MyProject.Utilities.DLL uses code from MyProject.DLL. Is this solved by clicking on properties and selecting "Dependencies"? I tried that but still don't seem to be accessing the namespaces of the assembly I have selected. Do I have to reference every assembly I need for each class library? Responses appreciated and thanks for your patience.

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  • Get a "sqlceqp35.dll" error when debugging but not when running deployed code.

    - by nj
    In our current windows mobile project a problem while debugging recently arised. When trying to debug the code it throws an exception on the open command on a connection to the local database. The message is "A SQL Server Compact DLL could not be loaded. Reinstall SQL Server Compact Edition. [ DLL Name = sqlceqp35.dll ]". Sometime it's an unknow error instead, with reference to the same file. If you execute the binary, thats deployd during the debug, on the device it runs without any problem. I've tried: Reinstall both .net and sqlce on the device. Changed the "specific version" on the reference properties in the project. The hardware I'm using is a Motorola MC70 with Windows mobile 5.0. The target platform of the project is windows mobile 5.0. Any ideas on what might cause this problem? EDIT: When I tried it on a MC75 I can debug it. The MC70 got OS Version: 05.01.0478 and the MC75 05.01.0478. My best guess now is that it's someway related to the OS version or the actual device.

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  • Trouble compiling C/C++ project in NetBeans 6.8 with MinGW on Windows

    - by dontoo
    I am learning C and because VC++ 2008 doesn't support C99 features I have just installed NetBeans and configure it to work with MinGW. I can compile single file project ( main.c) and use debugger but when I add new file to project I get error "undefined reference to ... function(code) in that file..". Obviously MinGW does't link my files or I don't know how properly add them to my project (c standard library files work fine). /bin/make -f nbproject/Makefile-Debug.mk SUBPROJECTS= .build-conf make[1]: Entering directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' /bin/make -f nbproject/Makefile-Debug.mk dist/Debug/MinGW-Windows/cppapplication_7.exe make[2]: Entering directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' mkdir -p dist/Debug/MinGW-Windows gcc.exe -o dist/Debug/MinGW-Windows/cppapplication_7 build/Debug/MinGW-Windows/main.o build/Debug/MinGW-Windows/main.o: In function `main': C:/Users/don/Documents/NetBeansProjects/CppApplication_7/main.c:5: undefined reference to `X' collect2: ld returned 1 exit status make[2]: *** [dist/Debug/MinGW-Windows/cppapplication_7.exe] Error 1 make[2]: Leaving directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' make[1]: *** [.build-conf] Error 2 make[1]: Leaving directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 1s) main.c #include "header.h" int main(int argc, char** argv) { X(); return (EXIT_SUCCESS); } header.h #ifndef _HEADER_H #define _HEADER_H #include <stdio.h> #include <stdlib.h> void X(void); #endif source.c #include "header.h" void X(void) { printf("dsfdas"); }

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  • How to get the equivalent of the accuracy in Google Map Geocoder V3

    - by Scorpi0
    Hi, I want to get geocode from google, and I used to do it with the V2 of the API. Google send in the json a pretty good information, the accuracy, reference here : http://code.google.com/intl/fr-FR/apis/maps/documentation/javascript/v2/reference.html#GGeoAddressAccuracy In V3, Google doesn't seem to send me exactly the same information. There is the array "adresse_component", which seem bigger if the accuracy is better, but not exactly. For example, I have a request accuracy to the street number, the array is of size 8. Another query is accuracy to the route, so less accuracy, but the array is style of size 8, as there is a row 'sublocality', which not appear in the first case. Ok, for a result, Google send a data 'types', which have the 'best' accuracy. This types are here : http://code.google.com/intl/fr-FR/apis/maps/documentation/geocoding/#Types But, there is no real order, and if I wan't the result better than postal_code, I have no clue to how to do that. So, how can I get this equivalent of the V2 accuracy, whithout some dumb and horrible code ?

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  • How do I create a python module from a fortran program with f2py?

    - by Lars Hellemo
    I am trying to read some smps files with python, and found a fortran implementation, so I thought I would give f2py a shot. The problem is that I have no experience with fortran. I have successfully installed gfortran and f2py on my Linux box and ran the example on thew f2py page, but I have some trouble compiling and running the large program. There are two files, one with a file reader wrapper and one with all the logic. They seem to call each other, but when I compile and link or try f2py, I get errors that they somehow can't find each other: f95 -c FILEWR~1.F f95 -c SMPSREAD.F90 f95 -o smpsread SMPSREAD.o FILEWR~1.o FILEWR~1.o In function `file_wrapper_' FILEWR~1.F(.text+0x3d) undefined reference to `chopen_' usrlibgcci486-linux-gnu4.4.1libgfortranbegin.a(fmain.o) In function `main' (.text+0x27) undefined reference to `MAIN__' collect2 ld returned 1 exit status I also tried changing the name to FILE_WRAPPER.F but that did not help. With f2py I found out I had to include a comment to get it to accept free format, and saved this as a new file and tried: f2py -c -m smpsread smpsread.f90 I get a lot of output and warnings, but the error seems to be this one: getctype: No C-type found in "{'typespec': 'type', 'attrspec': ['allocatable'], 'typename': 'node', 'dimension': [':']}", assuming void. The fortran 90 spms reader can be found here. Any help or suggestions appreciated.

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  • Volatile fields in C#

    - by Danny Chen
    From the specification 10.5.3 Volatile fields: The type of a volatile field must be one of the following: A reference-type. The type byte, sbyte, short, ushort, int, uint, char, float, bool, System.IntPtr, or System.UIntPtr. An enum-type having an enum base type of byte, sbyte, short, ushort, int, or uint. First I want to confirm my understanding is correct: I guess the above types can be volatile because they are stored as a 4-bytes unit in memory(for reference types because of its address), which guarantees the read/write operation is atomic. A double/long/etc type can't be volatile because they are not atomic reading/writing since they are more than 4 bytes in memory. Is my understanding correct? And the second, if the first guess is correct, why a user defined struct with only one int field in it(or something similar, 4 bytes is ok) can't be volatile? Theoretically it's atomic right? Or it's not allowed simply because that all user defined structs(which is possibly more than 4 bytes) are not allowed to volatile by design?

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  • Help with SQL Query

    - by djfrear
    With regards to the following statement: Select * From explorer.booking_record booking_record_ Inner Join explorer.client client_ On booking_record_.labelno = client_.labelno Inner Join explorer.tour_hotel tour_hotel_ On tour_hotel_.tourcode = booking_record_.tourrefcode Inner Join explorer.hotelrecord hotelrecord_ On tour_hotel_.hotelcode = hotelrecord_.hotelref Where booking_record_.bookingdate Not Like '0000-00-00' And booking_record_.tourdeparturedate Not Like '0000-00-00' And hotelrecord_.hotelgroup = "LPL" And Year(booking_record_.tourdeparturedate) Between Year(AddDate(Now(), Interval -5 Year)) And Year(Now()) My MySQL skills are certainly not up to scratch, the actual result set I wish to find is "a customer who has been to 5 or more LPL hotels in the past 5 years". So far I havent got as far as dealing with the count as I'm getting a huge number of results with some 250+ per customer. I assume this is to do with the way I'm joining tables. Schema wise the booking_record table contains a tour reference code, which links to tour_hotel which then contains a hotelcode which links to hotelrecord. This hotelrecord table contains the hotelgroup. The client table is joined to the booking_record via a booking reference and a client may have many bookings. If anyone could suggest a way for me to do this I'd be very grateful and hopefully learn enough to do it myself next time! I've been scratching my head over this one for a few hours now! Customers may have many bookings within booking_record Daniel.

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  • Thread-safe data structure design

    - by Inso Reiges
    Hello, I have to design a data structure that is to be used in a multi-threaded environment. The basic API is simple: insert element, remove element, retrieve element, check that element exists. The structure's implementation uses implicit locking to guarantee the atomicity of a single API call. After i implemented this it became apparent, that what i really need is atomicity across several API calls. For example if a caller needs to check the existence of an element before trying to insert it he can't do that atomically even if each single API call is atomic: if(!data_structure.exists(element)) { data_structure.insert(element); } The example is somewhat awkward, but the basic point is that we can't trust the result of "exists" call anymore after we return from atomic context (the generated assembly clearly shows a minor chance of context switch between the two calls). What i currently have in mind to solve this is exposing the lock through the data structure's public API. This way clients will have to explicitly lock things, but at least they won't have to create their own locks. Is there a better commonly-known solution to these kinds of problems? And as long as we're at it, can you advise some good literature on thread-safe design? EDIT: I have a better example. Suppose that element retrieval returns either a reference or a pointer to the stored element and not it's copy. How can a caller be protected to safely use this pointer\reference after the call returns? If you think that not returning copies is a problem, then think about deep copies, i.e. objects that should also copy another objects they point to internally. Thank you.

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  • Should I define a single "DataContext" and pass references to it around or define muliple "DataConte

    - by Nate Bross
    I have a Silverlight application that consists of a MainWindow and several classes which update and draw images on the MainWindow. I'm now expanding this to keep track of everything in a database. Without going into specifics, lets say I have a structure like this: MainWindow Drawing-Surface Class1 -- Supports Drawing DataContext + DataServiceCollection<T> w/events Class2 -- Manages "transactions" (add/delete objects from drawing) Class3 Each "Class" is passed a reference to the Drawing Surface so they can interact with it independently. I'm starting to use WCF Data Services in Class1 and its working well; however, the other classes are also going to need access to the WCF Data Services. (Should I define my "DataContext" in MainWindow and pass a reference to each child class?) Class1 will need READ access to the "transactions" data, and Class2 will need READ access to some of the drawing data. So my question is, where does it make the most sense to define my DataContext? Does it make sense to: Define a "global" WCF Data Service "Context" object and pass references to that in all of my subsequent classes? Define an instance of the "Context" for each Class1, Class2, etc Have each method that requires access to data define its own instance of the "Context" and use closures handle the async load/complete events? Would a structure like this make more sense? Is there any danger in keeping an active "DataContext" open for an extended period of time? Typical usecase of this application could range from 1 minute to 40+ minutes. MainWindow Drawing-Surface DataContext Class1 -- Supports Drawing DataServiceCollection<DrawingType> w/events Class2 -- Manages "transactions" (add/delete objects from drawing) DataServiceCollection<TransactionType> w/events Class3 DataServiceCollection<T> w/events

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  • Type or namespace could not be found

    - by Jason Shultz
    I'm using LINQ to SQL to connect my database to my home page. I created my datacontext (named businessModel.dbml) In it I have two tables named Category and Business. In home controller I reference the model and attempt to return to the view the table: var dataContext = new businessModelDataContext(); var business = from b in dataContext.Businesses select b; ViewData["WelcomeMessage"] = "Welcome to Jerome, Arizona!"; ViewData["MottoMessage"] = "Largest Ghost Town in America!"; return View(business); and in the view I have this: <%@ Import Namespace="WelcomeToJerome.Models" %> and <% foreach (business b in (IEnumerable)ViewData.Model) { %> <li><%= b.Title %></li> <% } %> Yet, in the view business is cursed with the red underline and say's that The type or namespace name 'business' could not be found (are you missing a using directive or an assembly reference?) What am I doing wrong? This has had me stumped all afternoon. link to all the code in pastebin: http://pastebin.com/es4RnS2q

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  • Question about WeakHashMap

    - by michael
    Hi, In the Javadoc of "http://java.sun.com/j2se/1.4.2/docs/api/java/util/WeakHashMap.html", it said "Each key object in a WeakHashMap is stored indirectly as the referent of a weak reference. Therefore a key will automatically be removed only after the weak references to it, both inside and outside of the map, have been cleared by the garbage collector." And then Note that a value object may refer indirectly to its key via the WeakHashMap itself; that is, a value object may strongly refer to some other key object whose associated value object, in turn, strongly refers to the key of the first value object. But should not both Key and Value should be used weak reference in WeakHashMap? i.e. if there is low on memory, GC will free the memory held by the value object (since the value object most likely take up more memory than key object in most cases)? And if GC free the Value object, the Key Object can be free as well? Basically, I am looking for a HashMap which will reduce memory usage when there is low memory (GC collects the value and key objects if necessary). Is it possible in Java? Thank you.

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  • User control loosing its contents when loaded programatically

    - by Phil
    I have a usercontrol which contains 2 repeaters and the code to populate them with data. If i manually insert this into the page then it works correctly, the repeaters populate etc. If I load it programatically using this method; 1) add class name to user control ClassName="ContentModule" 2) reference this in the default.aspx <%@ Reference Control="~/modules/content.ascx" %> 3) Add the code to my codebehind page_load to do the loading; Private loadmodule As ASP.ContentModule Try If themodule = "content" Then loadmodule = CType(LoadControl("~\Modules\Content.ascx"), ASP.ContentModule) Modulecontainer.Controls.Add(loadmodule) End If Catch ex As Exception Response.Write(ex.ToString & "<br />") End Try Nothing from within the usercontrol is loaded to the page. Although if I add some static text i.e "TEST" to the top of the usercontrol this is displayed ok on the default.aspx page. This makes me think that the control is loaded ok, but there is something in the way I have loaded it that is causing the contents to not properly execute. Very frustrating this one! Any help greatly appreciated!

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  • Does anyone have documentation on SHGetSysColor?

    - by Paulo Santos
    I'm trying to find any reference for this function, but I haven't found anything. All I have is an obscure KB from Microsoft referencing that a programmer made boo-boo when coding a part of the Windows Mobile 6 where he should call SHGetSysColor but instead he called GetSysColor that gives a complete different color, for the same spec. From what I could gather the GetSysColor read a color value in the registry from HKEY_LOCAL_MACHINE\Software\Microsoft\Color\SHColor or HKEY_LOCAL_MACHINE\Software\Microsoft\Color\DefSHColor and returns the color according to the index. In that registry I have the following value for a standard Win Mobile 6.5 "DefSHColor"=hex:\ ff,00,00,00,00,00,00,00,dd,dd,dd,00,ff,ff,cc,00,ff,ff,ff,00,15,af,bc,00,15,\ af,bc,00,c9,e7,e9,00,14,9c,a7,00,ff,ff,ff,00,14,9c,a7,00,14,9c,a7,00,14,9c,\ a7,00,15,af,bc,00,14,9c,a7,00,ff,ff,ff,00,c9,e7,e9,00,37,c7,d3,00,37,c7,d3,\ 00,ff,ff,ff,00,00,b7,c9,00,14,9c,a7,00,ff,ff,ff,00,15,af,bc,00,84,84,c3,00,\ 15,af,bc,00,14,9c,a7,00,ff,ff,ff,00,ff,ff,ff,00,00,00,00,00,ff,ff,ff,00,00,\ 00,00,00,ff,ff,ff,00,2e,44,4f,00,00,14,3c,00,00,f0,ff,00,ff,ff,ff,00,c9,e7,\ e9,00,14,9c,a7,00,ff,ff,ff,00,14,9c,a7,00 And I realized that each four bytes represents a different color (RR,GG,BB,AA -- The AA I'm assuming here, as every color there has the AA byte as 00 which would mean that it's a solid color). What I can't get a fix on is what each index mean, as I have 41 different colors in there. Googling for SHGetSysColor in gives me only 7 matches, two of them are the KB from Microsoft (one in English, the other in French) one is from a Russian site (which I don't read), yet another two are from the freepascal.org and one from Koders.com that is describing the commctl.def file. I went to the commctl.h trying to see if I could find reference tom this function, and found absolutely nothing. No search on MSDN, either fro Google, Bing, or the default MSDN search gave me any result. So, does anyone know what indexes are we talking about here?

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  • ADODB.Connection undefined

    - by Wes Groleau
    Reference http://stackoverflow.com/questions/1690622/excel-vba-to-sql-server-without-ssis After I got the above working, I copied all the global variables/constants from the routine, which included Const CS As String = "Driver={SQL Server};" _ & "Server=**;" _ & "Database=**;" _ & "UID=**;" _ & "PWD=**" Dim DB_Conn As ADODB.Connection Dim Command As ADODB.Command Dim DB_Status As Stringinto a similar module in another spreadsheet. I also copied Sub Connect_To_Lockbox() If DB_Status < "Open" Then Set DB_Conn = New Connection DB_Conn.ConnectionString = CS DB_Conn.Open ' problem! DB_Status = "Open" End If End SubI added the same reference (ADO 2.8) The first spreadsheet still works; the seccond at DB_Conn.Open pops up "Run-time error '-214767259 (80004005)': [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified" Removing the references on both, saving files, re-opening, re-adding the references doesn't help. The one still works and the other gets the error. ?!?

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  • Handling selection and deselection of objects in a user interface

    - by Dennis
    I'm writing a small audio application (in Silverlight, but that's not really relevant I suppose), and I'm a struggling with a problem I've faced before and never solved properly. This time I want to get it right. In the application there is one Arrangement control, which contains several Track controls, and every Track can contain AudioObject controls (these are all custom user controls). The user needs to be able to select audio objects, and when these objects are selected they are rendered differently. I can make this happen by hooking into the MouseDown event of the AudioObject control and setting state accordingly. So far so good, but when an audio object is selected, all other audio objects need to be deselected (well, unless the user holds the shift key). Audio objects don't know about other audio objects though, so they have no way to tell the rest to deselect themselves. Now if I would approach this problem like I did the last time I would pass a reference to the Arrangement control in the constructor of the AudioObject control and give the Arrangement control a DeselectAll() method or something like that, which would tell all Track controls to deselect all their AudioObject controls. This feels wrong, and if I apply this strategy to similar issues I'm afraid I will soon end up with every object having a reference to every other object, creating one big tightly coupled mess. It feels like opening the floodgates for poorly designed code. Is there a better way to handle this?

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