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  • Can JPA do batch update | put | write | insert as pm.makePersistentAll() does in GAE/J

    - by Kenyth
    I searched through multiple discussions here. Can someone just give me a quick and direct answer? And if with JPA you can't do a batch update, what if I don't use transaction, and just use the following flow: em = emf.getEntityManager // do some query // make some data modification em.persist(..) // do some query // make some data modification em.persist(..) // do some query // make some data modification em.persist(..) ... em.close() How does this compare to batch update with regard to performance, and compare to a single transaction commit, measured by RPC calls to datastore server, CPU cycles per request, or so. Does every call to em.persist(..) before em.close() trigger a RPC call to the datastore server? Thanks very much for any response!

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  • "Inlining" (kind of) functions at runtime in C

    - by fortran
    Hi, I was thinking about a typical problem that is very JIT-able, but hard to approach with raw C. The scenario is setting up a series of function pointers that are going to be "composed" (as in maths function composition) once at runtime and then called lots and lots of times. Doing it the obvious way involves many virtual calls, that are expensive, and if there are enough nested functions to fill the CPU branch prediction table completely, then the performance with drop considerably. In a language like Lisp, I could probably process the code and substitute the "virtual" call by the actual contents of the functions and then call compile to have an optimized version, but that seems very hacky and error prone to do in C, and using C is a requirement for this problem ;-) So, do you know if there's a standard, portable and safe way to achieve this in C? Cheers

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  • KindError: Property r must be an instance of SecondModel, why ?

    - by zjm1126
    class FirstModel(db.Model): p = db.StringProperty() r=db.ReferenceProperty(SecondModel) class SecondModel(db.Model): r = db.ReferenceProperty(FirstModel) class sss(webapp.RequestHandler): def get(self): a=FirstModel() a.p='sss' a.put() b=SecondModel() b.r=a b.put() a.r=b a.put() self.response.out.write(str(b.r.p)) the error is : Traceback (most recent call last): File "D:\Program Files\Google\google_appengine\google\appengine\ext\webapp\__init__.py", line 511, in __call__ handler.get(*groups) File "D:\zjm_code\helloworld\a.py", line 158, in get a.r=b File "D:\Program Files\Google\google_appengine\google\appengine\ext\db\__init__.py", line 3009, in __set__ value = self.validate(value) File "D:\Program Files\Google\google_appengine\google\appengine\ext\db\__init__.py", line 3048, in validate (self.name, self.reference_class.kind())) KindError: Property r must be an instance of SecondModel thanks

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  • Can I get parameter names/values procedurally from the currently executing function?

    - by Pwninstein
    I would like to do something like this: public MyFunction(int integerParameter, string stringParameter){ //Do this: LogParameters(); //Instead of this: //Log.Debug("integerParameter: " + integerParameter + // ", stringParameter: " + stringParameter); } public LogParameters(){ //Look up 1 level in the call stack (if possible), //Programmatically loop through the function's parameters/values //and log them to a file (with the function name as well). //If I can pass a MethodInfo instead of analyzing the call stack, great. } I'm not even sure what I want to do is possible, but it would be very nice to be able to automatically output parameter names/values at runtime to a file without explicitly writing the code to log them. Thanks!

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  • Calling Javascript after linking to another page

    - by kratos2488
    I am doing an integration with a support system (Helpstream) and I am currently working on doing some in-app context sensitive help. I have put in a link that will send the user to a section of Helpstream that will allow them to ask a question. Problem is, there are buttons on the page that call Javascript that will bring up a lightbox where the user fills out a form to submit a question. What I need to do is have that form come up after the user goes through the link, so essentially run the Javascript once the user hits the page. The call that I have to implement is NewTopic.CreateNew({type:"Question"}) Any tips would be greatly appreciated. Thanks in advance.

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  • Proper way to 100% wakes my device?

    - by quiel
    Do you have better way to make the device awakes by 100%? I repeatedly call the acquire() but I'm not sure if that is correct. Or should I just call the acquire() once? Or should I make use of Intent.ACTION_SCREEN_OFF? public class MyServiceThatKeepsTheDeviceAwake extends IntentService { ... @Override public void onCreate() { super.onCreate(); mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE); mWakeLock = mPowerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK |PowerManager.ACQUIRE_CAUSES_WAKEUP |PowerManager.ON_AFTER_RELEASE, TAG); } @Override public void onStart(Intent intent, int startId) { super.onStart(intent, startId); mWakeLock.acquire(); } // No release

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  • [C++] Simple inheritance question

    - by xbonez
    I was going over some sample questions for an upcoming test, and this question is totally confusing me. Any help would be appreciated. Consider the following code: class GraduateStudent : public Student { ... }; If the word "public" is omitted, GraduateStudent uses private inheritance, which means which of the following? GraduateStudent objects may not use methods of Student. GraduateStudent does not have access to private objects of Student. No method of GraduateStudent may call a method of Student. Only const methods of GraduateStudent can call methods of Student.

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  • Date range advanced count calculation in TSQL

    - by cihata87
    I am working on call center project and I have to calculate the call arrivals at the same time between specific time ranges. I have to write a procedure which has parameters StartTime, EndTime and Interval For Example: Start Time: 11:00 End Time: 12:00 Interval: 20 minutes so program should divide the 1-hour time range into 3 parts and each part should count the arrivals which started and finished in this range OR arrivals which started and haven't finished yet Should be like this: 11:00 - 11:20 15 calls at the same time(TimePeaks) 11:20 - 11:40 21 calls ... 11:40 - 12:00 8 calls ... Any suggestions how to calculate them?

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  • Trying to use a list iterator to print out entire linked list in Java. Infinite loop for some reaso

    - by Matt
    I created my list: private static List list = new LinkedList(); and my iterator: ListIterator itr = list.listIterator(); and use this code to try to print out the list... Only problem is, it never comes out of the loop. When it reaches the tail, shouldn't it come out of the loop, because there is no next? Or is it going back to the head like a circular linked list? It is printing so quickly and my computer locks up shortly after, so I can't really tell what is going on. while (itr.hasNext()) System.out.println(itr.next());

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  • doubt in - Function Objects - c++

    - by Eternal Learner
    I have a class class fobj{ public: fobj(int i):id(i) {} void operator()() { std::cout<<"Prints"<<std::endl; } private: int id; }; template<typename T> void func(T type) { type(); } My Doubt is if I invoke func like Method 1: func(fobj(1); the message I wanted to print is printed. I was always thinking I needed to do something like Method 2: fobj Iobj(1); // create an instance of the fobj class func(Iobj); //call func by passing Iobj(which is a function object) How does Method 1 work? I mean what exactly happens? and how is a call made to the operator() in class fobj ?

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  • null pointer exception in textview of setcontent

    - by kitokid
    I am getting the java.lang.NullPointerException on createTabContent for the following code. There are two tabspecs. When I called and set the tab , changed the tabs for the first time it is ok. But when i called again while I am on the second tab, its hit the null pointer exception for line : NoStudentText.setVisibility(View.VISIBLE); I will show No Student Text if there is no data for the student list. It shows the text for the first time call. But If I do second time call to that tab, got the error. tspecStudent.setContent(new TabContentFactory() { public View createTabContent(String arg0) { if(listStudent != null && listStudent .size() > 0) { //show the student list } else { TextView noStudentText = (TextView)findViewById(R.id.NoStudentText); noStudentText.setVisibility(View.VISIBLE); return noStudentText; } } });

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  • QuickTime movie disappearing from Javascript when scrolled offscreen in Firefox?

    - by c-had
    I have a web page I'm creating that uses Javascript to control an embedded QuickTime player. I add the QuickTime movie to the page using the AC_QuickTime.js file from Apple (as described here - http://developer.apple.com/mac/library/documentation/QuickTime/Conceptual/QTScripting_HTML/QTScripting_HTML_Document/ScriptingHTML.html#//apple_ref/doc/uid/TP40001525-2-SW1 ). Everything seems to be working fine - I can call methods on the QuickTime movie and control its playback (as well as get the current timestamp). The problem is that in Firefox, when I scroll down such that the QuickTime player is no longer visible, I get the following error every time I try to call a method on the QuickTime movie: Error calling method on NPObject! This does not occur in Safari. Why is this happening, and is there any way to work around this?

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  • Reading in MIPS external file so another file can use it?

    - by SkyWookie
    Hey all, I'm working on this final thing for my MIPS project and it's deceptively easy. I need to get a procedure (called feed) and let its main driver program use it by reading it in. I know that I'm supposed to use the call code 14 and .globl sym (I think) in order to feed it into the file and have it read it. I just need a basic tutorial or something, as I CANNOT find it on the Internet or in my book (just lists the call code, real helpful). Here's what I know: I need to use read, but I also need a file descriptor (don't know where to get it). I need to put the buffer in $a1 and the length in $a2. Well, that's about it. If there's any decent tutorial you could whip up or if there is one online that I don't see let me know please :). I just need a push in the right direction, I'm sure it can't be too difficult, just can't find any info on it!

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  • Why do you sometimes need to write <typename T> instead of just <T> ?

    - by StackedCrooked
    I was reading the Wikipedia article on SFINAE and encountered following code sample: struct Test { typedef int Type; }; template < typename T > void f( typename T::Type ) {} // definition #1 template < typename T > void f( T ) {} // definition #2 void foo() { f< Test > ( 10 ); //call #1 f< int > ( 10 ); //call #2 without error thanks to SFINAE } Now I've actually written code like this before, and somehow intuitively I knew that I needed to type "typename T" instead of just "T". However, it would be nice to know the actual logic behind it. Anyone care to explain?

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  • Restrict confirm message on page reload with f5

    - by Max
    In my JSP page I am using post method while submitting the page. So once I go from Page 1 to page 2. In Page 2, If I press F5 I am getting alert as "To display this page, Firefox must send information that will repeat any action (such as a search or order confirmation) that was performed earlier." I knew this question is a bit sarcastic but please give me an Idea. I can't change my method from POST to GET because I need to send large amount of data. Thanks in advance... Edited: In my Page1.JSP I call onClick function in that function I call action as "/page2servlet.do". Now, In Java side I use Spring Framework. With MVC Object I return to page2.jsp. So where do the response.sendRedirect Fit.

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  • curl problems in c++ class

    - by Danilo
    I read a few articles on c++ / curl here on stackoverflow and assembled the following. The main goal is to handle the whole request in an instance of a class -- and maybe later in a secondary thread. My problem is: "content_" seems to stay empty though its the same addr and HttpFetch.h: class HttpFetch { private: CURL *curl; static size_t handle(char * data, size_t size, size_t nmemb, void * p); size_t handle_impl(char * data, size_t size, size_t nmemb); public: std::string content_; static std::string url_; HttpFetch(std::string url); void start(); std::string data(); }; HttpFetch.cpp: HttpFetch::HttpFetch(std::string url) { curl_global_init(CURL_GLOBAL_ALL); //pretty obvious curl = curl_easy_init(); content_.append("Test"); std::cout << &content_ << "\n"; curl_easy_setopt(curl, CURLOPT_URL, &url); curl_easy_setopt(curl, CURLOPT_WRITEDATA, &content_); curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &HttpFetch::handle); //curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L); //tell curl to output its progress curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L); //std::cout << &content_ << "\n"; } void HttpFetch::start() { curl_easy_perform(curl); curl_easy_cleanup(curl); } size_t HttpFetch::handle(char * data, size_t size, size_t nmemb, void * p) { std::string *stuff = reinterpret_cast<std::string*>(p); stuff->append(data, size * nmemb); std::cout << stuff << "\n"; // has content from data in it! return size * nmemb; } main.cpp: #include "HttpFetch.h" int main(int argc, const char * argv[]) { HttpFetch call = *new HttpFetch("http://www.example.com"); call.start(); ::std::cout << call.content_ << "\n" } Thanks in advance

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  • Comparing an array of users to an array of structs with user object as attribute, and returning matc

    - by keruilin
    I have an array of users who are friends. Let us call this array: friends I then have an array of structs. Each struct has a user object as an attribute (it also has a rank attribute). Here's what the struct class looks like, to add some context: class Leader < Struct.new(:rank, :user); end Let us call this array of structs: all_leaders_plus_rank I want to compare friends and all_leaders_plus_rank, and add the match from all_leaders_plus_rank to a new array of structs called friendly_leaders.

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  • Java Map question

    - by user552961
    I have one Map that contains some names and numbers Map<String,Integer> abc = new TreeMap<String,Integer>(); It works fine. I can put some values in it but when I call it in different class it gives me wrong order. For example: I putted abc.put("a",1); abc.put("b",5); abc.put("c",3); some time it returns the order (b,a,c) and some time (a,c,b). What is wrong with it? Is there any step that I am missing when I call this map?

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  • Python: What does _("str") do?

    - by Rosarch
    I see this in the Django source code: description = _("Comma-separated integers") description = _("Date (without time)") What does it do? I try it in Python 3.1.3 and it fails: >>> foo = _("bar") Traceback (most recent call last): File "<pyshell#0>", line 1, in <module> foo = _("bar") NameError: name '_' is not defined No luck in 2.4.4 either: >>> foo = _("bar") Traceback (most recent call last): File "<pyshell#1>", line 1, in -toplevel- foo = _("bar") NameError: name '_' is not defined What's going on here?

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  • Low-overhead way to access the memory space of a traced process?

    - by vovick
    Hello all. I'm looking for an efficient way to access(for both read and write operations) the memory space of my ptraced child process. The size of blocks being accessed may vary from several bytes up to several megabytes in size, so using the ptrace call with PTRACE_PEEKDATA and PTRACE_POKEDATA which read only one word at a time and switch context every time they're called seems like a pointless waste of resources. The only one alternative solution I could find, though, was the /proc/<pid>/mem file, but it has long since been made read only. Is there any other (relatively simple) way to do that job? The ideal solution would be to somehow share the address space of my child process with its parent and then use the simple memcpy call to copy data I need in both directions, but I have no clues how to do it and where to begin. Any ideas?

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  • Java Wicket - Calling javascript ( JQuery ) before AJAX

    - by user1428051
    I got this thing i'm trying to solve: I got a ListView created using Wicket ( 1.5 ) with a lot of elements and a scroll. When new items are available, the user is asked if he would like to refresh the list via a message backed by an AjaxLink: public void onClick(AjaxRequestTarget ajaxTarget) { /* do something ... */ ajaxTarget.addComponent(_list); } So on click the list gets reloaded and the scroll position is reset to zero. Is there any way i can call JavaScript before the list reloads the save the scroll position? (I know how to get/save the scroll position ( .scrollTop() ) , i just don't know how to call a function right before AJAX ).

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  • Assign parameters to function according to parameter names

    - by Korcholis
    I have an assoc array with a list of what are parameters to me. Here's an example: array( 'param1' => 'value1', 'param4' => 'value4', 'param3' => 'value3', 'param2' => 'value2', ); Note that they may come unsorted. Now, is there a way I can make a call (static or from an instance, using call_user_func_array or similar) and correctly pass each value to each parameter? Just to be sure, an example function I'd like to call using that parameter array is one such this: exampleFunction($param1, $param2, $param3, $param4) { ... } PS: Reflection is great, but I'm concerned about execution times (which, at least, in Java tends to increase a lot when using Reflection). If you know any other way to do so, it would be awesome.

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