Search Results

Search found 13333 results on 534 pages for 'upper memory'.

Page 413/534 | < Previous Page | 409 410 411 412 413 414 415 416 417 418 419 420  | Next Page >

  • How are a session identifiers generated?

    - by Asaf R
    Most web applications depend on some kind of session with the user (for instance, to retain login status). The session id is kept as a cookie in the user's browser and sent with every request. To make it hard to guess the next user's session these session-ids need to be sparse and somewhat random. The also have to be unique. The question is - how to efficiently generate session ids that are sparse and unique? This question has a good answer for unique random numbers, but it seems not scalable for a large range of numbers, simply because the array will end up taking a lot of memory.

    Read the article

  • Garbage Collection Java

    - by simion
    On the slides i am revising from it says the following; Live objects can be identified either by maintaining a count of the number of references to each object, or by tracing chains of references from the roots. Reference counting is expensive – it needs action every time a reference changes and it doesn’t spot cyclical structures, but it can reclaim space incrementally. Tracing involves identifying live objects only when you need to reclaim space – moving the cost from general access to the time at which the GC runs, typically only when you are out of memory. I understand the principles of why reference counting is expensive but do not understand what "doesn’t spot cyclical structures, but it can reclaim space incrementally." means. Could anyone help me out a little bit please? Thanks

    Read the article

  • Howto check if a object is connected to another in hibernate

    - by codevourer
    Imagine two domain object classes, A and B. A has a bidirectional one-to-many relationship to B. A is related to thousands of B. The relations must be unique, it's not possible to have a duplicate. To check if an instance of B is already connected to a given instance of A, we could perform an easy INNER JOIN but this will only ensure the already persisted relations. What about the current transient relations? class A { @OneToMany private List<B> listOfB; } If we access the listOfB and perform a check of contains() this will fetch all the connected instances of B lazy from the datasource. I only want to validate them by their primary-key. Is there an easy solution where I can do things like "Does this instance of A is connected with this instance of B?" Without loading all these data into memory and perform a based on collections?

    Read the article

  • controlling the class names generated by JAXB for xsd:attributeGroup?

    - by Stephen Winnall
    I am using JAXB to bind XML to Java for an application that I am writing. I have an element called measure which contains two amount elements called amount and maxAmount, with which I want to model a lower and an upper limiting value. amount and maxAmount are otherwise identical and I would like them to be implemented with the same class when unmarshalled into Java. The following is an extract from the XML schema which I feed to JAXB: <xsd:attributeGroup name="AmountAttributes"> <xsd:attribute name="quantity" type="xsd:decimal"/> <xsd:attribute name="numerator" type="xsd:nonNegativeInteger"/> <xsd:attribute name="denominator" type="xsd:positiveInteger"/> </xsd:attributeGroup> <xsd:element name="measure"> <xsd:complexType> <xsd:sequence> <xsd:element minOccurs="0" name="amount"> <xsd:complexType> <xsd:attributeGroup ref="mpr:AmountAttributes"/> </xsd:complexType> </xsd:element> <xsd:element minOccurs="0" name="maxAmount"> <xsd:complexType> <xsd:attributeGroup ref="mpr:AmountAttributes"/> </xsd:complexType> </xsd:element> </xsd:sequence> </xsd:complexType> </xsd:element> JAXB creates from this a more elaborate version of the following: public class Measure { protected Measure.Amount amount; protected Measure.MaxAmount maxAmount; public static class Measure.Amount {} public static class Measure.MaxAmount {} } Measure.Amount and Measure.MaxAmount are identical except for their names, but - of course - as far as Java is concerned they have little to do with each other. Is there a way of making JAXB use the same class for both amount and maxAmount? Just to come completely clean ;-) I should mention that I generate the XML schema from RNC using Trang. If the answer to the question is "change the XML schema", I have the supplementary question "how do I change the RNC to produce that XML schema?". My RNC looks like this: AmountAttributes = QuantityAttribute? & attribute numerator { xsd:nonNegativeInteger }? & attribute denominator { xsd:positiveInteger }? QuantityAttribute = attribute quantity { xsd:decimal } Measure = element measure { element amount { AmountAttributes }?, element maxAmount { AmountAttributes }? }+ I use RNC because I find it simpler to understand, but if the solution to my problem means just using XML Schema, so be it. Steve

    Read the article

  • C Programming: calling free() on error?

    - by kouei
    Hi all, This a follow up on my previous question. link here. My question is: Let's say I have the following code.. char* buf = (char*) malloc(1024); ... for(; i<20; i++) { if(read(fd, buf, 1024) == -1) { // read off a file and store in buffer perror("read failed"); return 1; } ... } free(buf); what i'm trying to get at is that - what if an error occurs at read()? does that mean my allocated memory never gets freed? If that's the case, how do I handle this? Should I be calling free() as part of error handling? Once again, I apologize for the bad English. ^^; Many thanks, K.

    Read the article

  • [Reloaded] Error while sorting filtered data from a GridView

    - by Bogdan M
    Hello guys, I have an error I cannot solve, on a ASP.NET website. One of its pages - Countries.aspx, has the following controls: a CheckBox called "CheckBoxNAME": < asp:CheckBox ID="CheckBoxNAME" runat="server" Text="Name" /> a TextBox called "TextBoxName": < asp:TextBox ID="TextBoxNAME" runat="server" Width="100%" Wrap="False"> < /asp:TextBox> a SQLDataSource called "SqlDataSourceCOUNTRIES", that selects all records from a Table with 3 columns - ID (Number, PK), NAME (Varchar2(1000)), and POPULATION (Number) called COUNTRIES < asp:SqlDataSource ID="SqlDataSourceCOUNTRIES" runat="server" ConnectionString="< %$ ConnectionStrings:myDB %> " ProviderName="< %$ ConnectionStrings:myDB.ProviderName %> " SelectCommand="SELECT COUNTRIES.ID, COUNTRIES.NAME, COUNTRIES.POPULATION FROM COUNTRIES ORDER BY COUNTRIES.NAME, COUNTRIES.ID"> < /asp:SqlDataSource> a GridView called GridViewCOUNTRIES: < asp:GridView ID="GridViewCOUNTRIES" runat="server" AllowPaging="True" AllowSorting="True" AutoGenerateColumns="False" DataSourceID="SqlDataSourceCOUNTRIES" DataKeyNames="ID" DataMember="DefaultView"> < Columns> < asp:CommandField ShowSelectButton="True" /> < asp:BoundField DataField="ID" HeaderText="Id" SortExpression="ID" /> < asp:BoundField DataField="NAME" HeaderText="Name" SortExpression="NAME" /> < asp:BoundField DataField="POPULATION" HeaderText="Population" SortExpression="POPULATION" /> < /Columns> < /asp:GridView> a Button called ButtonFilter: < asp:Button ID="ButtonFilter" runat="server" Text="Filter" onclick="ButtonFilter_Click"/> This is the onclick event: protected void ButtonFilter_Click(object sender, EventArgs e) { Response.Redirect("Countries.aspx?" + (this.CheckBoxNAME.Checked ? string.Format("NAME={0}", this.TextBoxNAME.Text) : string.Empty)); } Also, this is the main onload event of the page: protected void Page_Load(object sender, EventArgs e) { if (Page.IsPostBack == false) { if (Request.QueryString.Count != 0) { Dictionary parameters = new Dictionary(); string commandTextFormat = string.Empty; if (Request.QueryString["NAME"] != null) { if (commandTextFormat != string.Empty && commandTextFormat.EndsWith("AND") == false) { commandTextFormat += "AND"; } commandTextFormat += " (UPPER(COUNTRIES.NAME) LIKE '%' || :NAME || '%') "; parameters.Add("NAME", Request.QueryString["NAME"].ToString()); } this.SqlDataSourceCOUNTRIES.SelectCommand = string.Format("SELECT COUNTRIES.ID, COUNTRIES.NAME, COUNTRIES.POPULATION FROM COUNTRIES WHERE {0} ORDER BY COUNTRIES.NAME, COUNTRIES.ID", commandTextFormat); foreach (KeyValuePair parameter in parameters) { this.SqlDataSourceCOUNTRIES.SelectParameters.Add(parameter.Key, parameter.Value.ToUpper()); } } } } Basicly, the page displays in the GridViewCOUNTRIES all the records of table COUNTRIES. The scenario is the following: - the user checks the CheckBox; - the user types a value in the TextBox (let's say "ch"); - the user presses the Button; - the page loads displaying only the records that match the filter criteria (in this case, all the countries that have names containing "Ch"); - the user clicks on the header of the column called "Name" in order to sort the data in the GridView Then, I get the following error: ORA-01036: illegal variable name/number. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Data.OracleClient.OracleException: ORA-01036: illegal variable name/number Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Any help is greatly appreciated, tnks. PS: I'm using ASP.NET 3.5, under Visual Studio 2008, with an OracleXE database.

    Read the article

  • Quick way to do data lookup in PHP

    - by Ghostrider
    I have a data table with 600,000 records that is around 25 megabytes large. It is indexed by a 4 byte key. Is there a way to find a row in such dataset quickly with PHP without resorting to MySQL? The website in question is mostly static with minor PHP code and no database dependencies and therefore fast. I would like to add this data without having to use MySQL if possible. In C++ I would memory map the file and do a binary search in it. Is there a way to do something similar in PHP?

    Read the article

  • running Hadoop software on office computers (when they are idle)

    - by Shahbaz
    Is there a project which helps setup a Hadoop cluster on office desktops, when they are idle? I'd like to experiment with Hadoop/MR/hbase but don't have acces to 5-10 computers. The computers at work are idle after hours and are connected to each other through a very high speed connection. What's more, data on these computers stays within our network so there is no privacy issue. In order for this to work I need a fairly light weight monitor running on each machine. When the computer has been idle for X hours, it will join the cluster. If the user logs on, it has to drop out of the cluster and return all CPU/memory back. Does something like this exist?

    Read the article

  • Has anybody used the WB B-tree library?

    - by Chris B
    I stumbled across the WB on-disk B-tree library: http://people.csail.mit.edu/jaffer/WB It seems like it could be useful for my purposes (swapping data to disk during very large statistical calculations that do not fit in memory), but I was wondering how stable it is. Reading the manual, it seems worringly 'researchy' - there are sections labelled [NOT IMPLEMENTED] etc. But maybe the manual is just out-of-date. So, is this library useable? Am I better off looking at Tokyo Cabinet, MemcacheDB, etc.? By the way I am working in Java.

    Read the article

  • how to generate large image in compact framework

    - by Buthrakaur
    I need to generate large images (A4 image at 200 DPI, PNG format would be fine) in my compact framework application. This is impossible to do in standard way due to memory limitations (such big image will throw OOMException). Is there any library which offers file-backed stream image generation? Or I could generate many smaller stripes of images (each stripe representing a row of the large image) using standard Bitmap approach, but I need to merge them together afterwards - is there any method how to merge many smaller images into one large without having to instantiate large Bitmap instance (which would again cause OOM)?

    Read the article

  • Objective-C: Initializing char with char at index of string.

    - by Mr. McPepperNuts
    unichar myChar = [myString characterAtIndex:0]; [myNSMutableArray addObject:myChar]; I am trying to insert the first char of a string into an array, to create an array of chars. the first line does not give me an error. The second line however, provides the following error: warning: passing argument 1 of 'addObject:' makes pointer from integer without a cast This also crashes the application with a "bad address" error. I thought this error was due to a problem with memory allocation. Can someone shed some light on this.

    Read the article

  • How to create a new IDA project based on an existing one with different offsets?

    - by tbergelt
    I have an existing IDA Pro project for a C166 processor embedded application. This project already has many functions, variables, etc defined. There are different versions of the embedded application I am looking at. The different versions of the application are 99% the same, but with slight variations in code and data that cause functions and variables to be at different memory offsets. I want to create a new IDA project for a different version of the application. I would like to somehow import all of my function and variable definitions from my existing IDA project. I would like IDA to recognize the signatures of the existing function definitions and define them at there new location in the new project. How can I do this? Are there certain plugins for IDA I can chain together?

    Read the article

  • Why can't I put a jquery-ui progressbar inside a div with fixed position?

    - by Matthew
    I started the source from this progressbar example, and it works fine. My only change was to set the width of the progressbar to "20%". <!DOCTYPE html> <html> <head> <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script> <script> $(document).ready(function() { $("#progressbar").progressbar({ value: 37 }).css({ width : "20%"}); }); </script> </head> <body style="font-size:62.5%;"> <div id="progressbar"></div> </body> </html> I then put the progressbar inside another div, and used css to fix that div in the upper-right-hand corner. <!DOCTYPE html> <html> <head> <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/> <style type="text/css"> #testContainer { position : fixed; top : 6; right : 6; } </style> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script> <script> $(document).ready(function() { $("#progressbar").progressbar({ value: 37 }).css({ width : "20%"}); }); </script> </head> <body style="font-size:62.5%;"> <div id="testContainer"> <div id="progressbar"></div> </div> </body> </html> The progressbar becomes a slim vertical line on the left side of the screen. What am I doing wrong? I'm new to web development in general, and jquery in particular, so please forgive me if this is a stupid question.

    Read the article

  • Is it possible to find out what FlashBuilder is doing during compilation?

    - by justkevin
    I've found that Flash Builder 4 (formerly Flex Builder) has trouble working with large projects. After a certain point, builds seem to take longer and longer. I've tried many different ways of improving build time including: Moving embedded resources into externally linked projects. Using -incremental. Tweaking the .ini jvm settings including memory and -server. Turning off automatic build (I'd prefer not to have to do this, because one of the main reasons for using an IDE is to be told about errors as you make them). Deleting the project and re-checking out from the repository. While some of these may help a bit, the performance is still annoyingly slow. I feel if I knew what was taking so long I could refactor my projects to build faster. Is there some setting that tells FlashBuilder to let me see what parts of the build process take so much time?

    Read the article

  • How do I write Push and Pop in Scheme?

    - by kunjaan
    Right now I have (define (push x a-list) (set! a-list (cons a-list x))) (define (pop a-list) (let ((result (first a-list))) (set! a-list (rest a-list)) result)) But I get this result: Welcome to DrScheme, version 4.2 [3m]. Language: Module; memory limit: 256 megabytes. > (define my-list (list 1 2 3)) > (push 4 my-list) > my-list (1 2 3) > (pop my-list) 1 > my-list (1 2 3) What am I doing wrong? Is there a better way to write push so that the element is added at the end and pop so that the element gets deleted from the first?

    Read the article

  • c, pass awk syntax as argument to execl

    - by Skuja
    I want to run following command in c to read systems cpu and memory usage: ps aux|awk 'NR > 0 { cpu +=$3; ram+=$4 }; END {print cpu,ram}' I am trying to pass it to execl command and after that read its output: execl("/bin/ps", "/bin/ps", "aux|awk", "'NR > 0 { cpu +=$3; ram+=$4 }; END {print cpu,ram}'",(char *) 0); but in terminal i am getting following error: ERROR: Unsupported option (BSD syntax) I would like to know how to properly pass awk as argument to execl?

    Read the article

  • Java Web App: Passing form parameters across multiple pages

    - by digiarnie
    Hi, what is the best practice or best way of passing form parameters from page to page in a flow? If I have a flow where a user enters data in a form and hits next and repeats this process until they get to an approval page, what ways could I approach this problem to make the retention of data as simple as possible over the flow? I guess you could put all the information as you go in the session but could you get into memory issues if a lot of people are using your app and going through the flow at the same time?

    Read the article

  • Forcing a templated object to construct from a pointer

    - by SalamiArmi
    I have a fictional class: template<typename T> class demonstration { public: demonstration(){} ... T *m_data; } At some point in the program's execution, I want to set m_data to a big block of allocated memory and construct an object T there. At the moment, I've been using this code: void construct() { *m_data = T(); } Which I've now realised is probably not the best idea... wont work under certain cirumstances, if T has a private assignment operator for example. Is there a normal/better way to do what I'm attempting here?

    Read the article

  • Freeing JavaScript object

    - by pion
    I am looking at the example from http://www.javascriptkit.com/javatutors/oopjs.shtml var person = new Object() person.name = "Tim Scarfe" person.height = "6Ft" But there is no mention how to "free" it in order to avoid memory leak. Will the following code free it? person = null; How do you free a JavaScript Object using "new Object()? How do you free a JavaScript Array allocated using "new Array(10)"? How do you free a JavaScript JSON allocated using "var json = {"width": 480, "height": 640}"? Thanks in advance for your help.

    Read the article

  • Is it faster to use a complicated boolean to limit a ResultSet at the MySQL end or at the Java end?

    - by javanix
    Lets say I have a really big table filled with lots of data (say, enough not to fit comfortably in memory), and I want to analyze a subset of the rows. Is it generally faster to do: SELECT (column1, column2, ... , columnN) FROM table WHERE (some complicated boolean clause); and then use the ResultSet, or is it faster to do: SELECT (column1, column2, ... , columnN) FROM table; and then iterate over the ResultSet, accepting different rows based on a java version of your boolean condition? I think it comes down to whether the Java iterator/boolean evaluator is faster than the MySQL boolean evaluator.

    Read the article

  • usage of 2 charectors in single qoutes in c

    - by user1632141
    #include<stdio.h> int main() { char ch = 'A'; printf("%d\n",'ag'); printf("%d\n",'a'); printf("%d, %d, %d, %d", sizeof(ch), sizeof('a'), sizeof('Ag'), sizeof(3.14f)); return 0; } I used to have many doubts on the output of this question while running on g++ and gcc. But I have cleared almost all the doubts by referring these links: Single and double quotes in C/C++ Single quotes vs. double quotes in C I still need to understand one thing about the output of this question. Can someone please explain the output of printf("%d\n",'ag'); mentioned above in the program. How is it actually stored in the memory? The output for the program on the Linux/GCC platform is: 24935 97 1, 4, 4, 4

    Read the article

  • Detect movie being played (Windows)

    - by modosansreves
    Watching a movie is quite a different user activity. User doesn't touch neither mouse nor keyboard. Yet he 'actively' uses the computer. Thus, screensaver shouldn't run, indexing should be performed with care etc. On the other side, playing video requires either using direct write to video memory, or DirectShow, or some other API. This may be the key to the answer. What is the Dead Simple Way to determine that a video is being played?

    Read the article

  • In C, as free() knows an array size, why isn't there a function that gets the array size? [closed]

    - by user354959
    Possible Duplicate: If free() knows the length of my array, why can’t I ask for it in my own code? Searching around (including here at stackoverflow), I got that malloc() allocates an array and also creates a header to control the array info. In this header, there's also the array size. free() use such information to know how to deallocate that array. So, if the array size info is "there" (somewhere in the memory), why there isn't a function that returns an array size, looking for this at the array header? Or am I missing something?

    Read the article

  • Unit testing with serialization mock objects in C++

    - by lhumongous
    Greetings, I'm fairly new to TDD and ran across a unit test that I'm not entirely sure how to address. Basically, I'm testing a couple of legacy class methods which read/write a binary stream to a file. The class functions take a serializable object as a parameter, which handles the actual reading/writing to the file. For testing this, I was thinking that I would need a serialization mock object that I would pass to this function. My initial thought was to have the mock object hold onto a (char*) which would dynamically allocate memory and memcpy the data. However, it seems like the mock object might be doing too much work, and might be beyond the scope of this particular test. Is my initial approach correct, or can anyone think of another way of correctly testing this? Thanks!

    Read the article

< Previous Page | 409 410 411 412 413 414 415 416 417 418 419 420  | Next Page >