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  • Navigate to the Same Page After Action in JSF 2

    - by shipmaster
    I have a component done in JSF 1.x, this component has a command button as follows <h:commandButton ... action="#{templateController.next}" /> Where templateController was passed as an EL binding and can be any object that implements a certain interface. The generic implementation of next() was just executing code and then returning an empty string causing the same page to refresh: public String next() { ..... return ""; } Now I am trying to port that component to JSF 2, my problem is that an empty string doesn't cause the same page to refresh anymore, instead, the framework tries to redirect to a page called ".jsf" i.e it just appends .jsf to whatever the outcome is. My question is how to return an outcome that causes the current page to refresh. My component is generic and I don't know before hand the name of the page it is going to be used on. Thanks

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  • Integrate flex 3.5 projects in flash builder 4 beta 2

    - by Cyrill Zadra
    Hi I'm currently using Flex Builder 3 and Flex SDK 3.5 for my projects. But I'd like to try out the new Flash Builder 4. So I downloaded and installed the new software, configured all the additional software like subversion, server adapter .. and finally a importet my 2 projects. 1) Main Project (includes a swc generated by the Library Project) (flex sdk 3.5) 2) Library Project (flex sdk 3.4) After the import and project cleanup the project is running perfectly. But as soon as I replace the existing LibraryProject.swc through a new one (compiled with flash builder 4 beta 2 sdk 3.4) VerifyError: Error #1014: class mx.containers::Canvas not found. VerifyError: Error #1014: class mx.containers::HBox not found. VerifyError: Error #1014: class IWatcherSetupUtil not found. ... and several others not found errors. Does anyone has the same error. How can I get my project running again? thanks & regards cyrill

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  • Using CSS Classes for indivdual effects - opinions?

    - by Cool Hand Luke UK
    Hey, Just trying to canvas some opinions here. I was wondering how people go about adding individual effects to html elements. Take this example: you have three types of h1 titles all the same size but some are black some are gold and some are white. Some have a text-shadow etc. Would you create separate CSS classes and add them do the h1 tag or would you create a new single class for each different h1 title type (with grouped CSS elements)? With singular class for each effect you can build up combos of classes in html class="gold shadow" but also how would you name them. For example its bad practice to give classes and id names associated to colours, because it doesn't define what it does well. However is this ok with textual CSS classes? Just wondering what others do, I know there are no hard and fast rules. Cheers.

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  • Java type for date/time when using Oracle Date with Hibernate

    - by Marcus
    We have a Oracle Date column. At first in our Java/Hibernate class we were using java.sql.Date. This worked but it didn't seem to store any time information in the database when we save so I changed the Java data type to Timestamp. Now we get this error: springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.dao.an notation.PersistenceExceptionTranslationPostProcessor#0' defined in class path resource [margin-service-domain -config.xml]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreatio nException: Error creating bean with name 'sessionFactory' defined in class path resource [m-service-doma in-config.xml]: Invocation of init method failed; nested exception is org.hibernate.HibernateException: Wrong column type: CREATE_TS, expected: timestamp Any ideas on how to map an Oracle Date while retaining the time portion? Update: I can get it to work if I use the Oracle Timestamp data type but I don't want that level of precision ideally. Just want the basic Oracle Date.

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  • Having template function defination in cpp file - Not work for VC6

    - by Yan Cheng CHEOK
    I have the following source code : // main.cpp #include "a.h" int main() { A::push(100); } // a.cpp #include "a.h" template <class T> void A::push(T t) { } template void A::push(int t); // a.h #ifndef A_H class A { public: template <class T> static void push(T t); }; #endif The code compiled charming and no problem under VC2008. But when come to my beloved VC6, it give me error : main.obj : error LNK2001: unresolved external symbol "public: static void __cdecl A::push(int)" (?push@A@@SAXH@Z) Any workaround? I just want to ensure my function definition is re-inside cpp file.

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  • DataBinding to ListView

    - by Neir0
    Hi, I have a class public class Foo { public List<string> list1 { get; set;} public List<string> list2 { get; set; } public string url; } and a ListView with two columns <ListView Name="listview" ItemsSource="{Binding}"> <ListView.View> <GridView> <GridViewColumn Header="list1" DisplayMemberBinding="{Binding Path=list1}" /> <GridViewColumn Header="list2" DisplayMemberBinding="{Binding Path=list2}" /> </GridView> </ListView.View> </ListView> How i can to bind instance of Foo class to ListView? Here i set DataContext listview.DataContext = new Foo() { list1 = new[] { "dsfasd", "asdfasdf", "asdf", "asdfasd" }.ToList(), list2 = new[] { "dsfasd", "asdfasdf", "asdf", "asdfasd" }.ToList() }; But it's not work.

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  • JSF2 and Richfaces 3.3.3 application on tomcat 6.0 crashes with a StackOverflowError

    - by Vivek Madapura V
    Hi, I am using JSF 2 and richfaces 3.3.3 for an application hosted on tomcat 6.0.20. The application crashes as soon as a request is made via the browser (Mozilla and IE). My web.xml looks like this: <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>TestJSF</display-name> <welcome-file-list> <welcome-file>pages/login.xhtml</welcome-file> </welcome-file-list> <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>/faces/*</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.xhtml</url-pattern> </servlet-mapping> <context-param> <description>State saving method: 'client' or 'server' (=default). See JSF Specification 2.5.2</description> <param-name>javax.faces.STATE_SAVING_METHOD</param-name> <param-value>server</param-value> </context-param> <context-param> <param-name>javax.faces.DISABLE_FACELET_JSF_VIEWHANDLER</param-name> <param-value>true</param-value> </context-param> <context-param> <param-name>org.richfaces.SKIN</param-name> <param-value>blueSky</param-value> </context-param> <context-param> <param-name>org.richfaces.CONTROL_SKINNING</param-name> <param-value>enable</param-value> </context-param> <context-param> <param-name>javax.faces.DEFAULT_SUFFIX</param-name> <param-value>.xhtml</param-value> </context-param> <context-param> <param-name>javax.faces.FACELETS_SKIP_COMMENTS</param-name> <param-value>true</param-value> </context-param> <listener> <listener-class>com.sun.faces.config.ConfigureListener</listener-class> </listener> <filter> <display-name>RichFaces Filter</display-name> <filter-name>richfaces</filter-name> <filter-class>org.ajax4jsf.Filter</filter-class> </filter> <filter-mapping> <filter-name>richfaces</filter-name> <servlet-name>Faces Servlet</servlet-name> <dispatcher>REQUEST</dispatcher> <dispatcher>FORWARD</dispatcher> <dispatcher>INCLUDE</dispatcher> </filter-mapping> </web-app> The exception is javax.servlet.ServletException: Servlet execution threw an exception org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:530) com.sun.faces.context.ExternalContextImpl.dispatch(ExternalContextImpl.java:542) com.sun.faces.application.view.JspViewHandlingStrategy.executePageToBuildView(JspViewHandlingStrategy.java:359) com.sun.faces.application.view.JspViewHandlingStrategy.buildView(JspViewHandlingStrategy.java:150) com.sun.faces.application.view.JspViewHandlingStrategy.renderView(JspViewHandlingStrategy.java:190) com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:127) org.ajax4jsf.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:100) org.ajax4jsf.application.AjaxViewHandler.renderView(AjaxViewHandler.java:176) com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:117) com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97) com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:135) javax.faces.webapp.FacesServlet.service(FacesServlet.java:309) The stack trace is recursively logged with this until the StackOverflowError occurrs. If I remove all the configurations related to Richfaces, the application works like charm. Any advice is much appreciated.

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  • Only show content when certain criteria is met?

    - by Elliot
    I'm wondering if theres a best practice for what I'm trying to accomplish... First we have the model categories, categories, has_many posts. Now lets say, users add posts. Now, I have a page, that I want to display only the current user's posts by category. Lets say we have the following categories: A, B, and C User 1, has posted in Categories A and B. In my view I have something like: @categories.each do |category| category.name @posts.each do |post| if post.category_id==category.id post content here end end end The problem with this, is I'm going to show the empty category, as well as the categories that do have content. Is there a more efficient way of going about this? As I don't want to show the empty categories. Best, Elliot

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  • What is Perl's equivalent to awk's /text/,/END/ ?

    - by kSiR
    I am looking to replace a nasty shell script that uses awk to trim down some HTML. The problem is I cannot find anything in Perl that does the aforementioned function awk '/<TABLE\ WIDTH\=\"100\%\" BORDER\=1\ CELLSPACING\=0><TR\ class\=\"tabhead\"><TH>State<\/TH>/,/END/' How can I do this in Perl? the expected output would be <TABLE WIDTH="100%" BORDER=1 CELLSPACING=0><TR class="tabhead"><TH>State</TH> The Perl flipflop operator gives me WAY more. (Everything between the asterisks is junk) *<h2>Browse Monitors (1 out of 497)</h2><br><font size="-1" style="font-weight:normal"> Use the <A HREF=/SiteScope/cgi/go.exe/SiteScope?page=monitorSummary&account=login15 >Monitor Description Report</a> to view current monitor configuration settings.</font>*<TABLE WIDTH="100%" BORDER=1 CELLSPACING=0><TR class="tabhead"><TH>State</TH>

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  • C# can I lock a method parameter?

    - by 5YrsLaterDBA
    We have a class variable ArrayList binaryScanData in a class. In all methods having access to it, we put lock(binaryScanData) on it because it is shared. Now we want to move one of those methods out to another util class to make it a static method. We will pass that binaryScanData into the method like this: public static void convertAndSaveRawData(ref MemoryStream output, ref ArrayList binaryScanData) Our questions are followed: how can we sychoronize that binaryScanData? can we do the same as it is originally? ref is necessary? It will only be read in that convertAndSaveRawData method.

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  • hyperLink on jsf error messages problem

    - by user234194
    I am trying to put link in the error messages produced by JSF. For this I am using the custom renderer, it works(clicking the error, focuses the respective input field) but the problem is , all the form values gets empty. ie when error occurs, all the input fields get empty. Any suggestion will be appreciated. package custom; public class CustomErrorRenderer extends Renderer { @Override @SuppressWarnings("unchecked") public void encodeEnd(FacesContext context, UIComponent component) throws IOException { ResponseWriter writer = context.getResponseWriter(); writer.startElement("div", component); writer.writeAttribute("id", component.getClientId(context), "id"); writer.writeAttribute("style", "color: red", null); writer.startElement("ul", null); Iterator clientIds = context.getClientIdsWithMessages(); while (clientIds.hasNext()) { String clientId = clientIds.next(); Iterator messages = context.getMessages(clientId); if (!messages.hasNext()) { continue; } String javaScript = "var field = document.getElementById('" + clientId + "');" + "if(field == null) return false;" + "field.focus(); return false;"; writer.startElement("li", null); writer.startElement("a", null); writer.writeAttribute("onclick", javaScript, null); writer.writeAttribute("href", "#", null); while (messages.hasNext()) { writer.writeText(messages.next().getSummary(), null); } writer.endElement("a"); writer.endElement("li"); } writer.endElement("ul"); writer.endElement("div"); } } This renderer is defined in faces-config.xml: add to base HTML_BASIC renderkit HTML_BASIC HTML_BASIC CustomErrorRenderer javax.faces.Output custom.CustomErrorRenderer custom.CustomErrorRenderer CustomErrorMessages custom.Errors javax.faces.component.UIOutput a tag class: package custom; import javax.faces.webapp.UIComponentELTag; public class CustomErrorTag extends UIComponentELTag { @Override public String getComponentType() { return "custom.Errors"; } @Override public String getRendererType() { return "custom.CustomErrorRenderer"; } } This is defined in a TLD file: http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1" 1.0 custom http://custom errors custom.CustomErrorTag empty This goes at the top of the JSP page: <%@ taglib prefix="custom" uri="http://custom"%

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  • Groovy Prototype Object

    - by Holden
    I have a method with an incoming variable, which represents a script. e.g. hello.groovy Foo.init(this) Foo.groovy class Foo { static init(app) { } } What is the best way to add a ton of new functionality to the app variable in the init method? Basically, I would like to add all the functionality of another object to the app object. For instance, if I had another class: class Bar { def a() { } def b() { } } I would like the app object to basically be a new Bar(). In JavaScript, this is easy by using the prototype object, but I cannot seem to get it working in groovy. What is the best way to accomplish this? Or should I be doing something differently?

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  • Visualforce dataTable: is there a way to stop it from rendering cellpadding attribute?

    - by codeulike
    In Visualforce, I'm using an <apex:dataTable> component as follows: <apex:dataTable value="{!Qualifications}" var="qual" styleClass="cv_table" > <!-- etc... --> ... and then I'm using CSS to style the table, via the class name. Trouble is, VisualForce renders HTML like this: <table class="cv_table" id="j_id0:j_id26" border="0" cellpadding="0" cellspacing="0"> <!-- etc... --> The class attribute is there as I wanted, but there's also cellpadding and cellspacing specified, that interfere with my CSS. Is there a way to stop Visualforce from rendering the cellpadding and cellspacing attributes for an <apex:dataTable>?

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  • C# threading pattern that will let me flush

    - by Jeff Alexander
    I have a class that implements the Begin/End Invocation pattern where I initially used ThreadPool.QueueUserWorkItem() to do thread my work. I now have the side effect where someone using my class is calling the Begin (with callback) a ton of times to do a lot of processing so ThreadPool.QueueUserWorkItem is creating a ton of threads to do the processing. That in itself isn't bad but there are instances where they want to abandon the processing and start a new process but they are forced to wait for their first request to finish. Since ThreadPool.QueueUseWorkItem() doesn't allow me to cancel the threads I am trying to come up with a better way to queue up the work and maybe use an explicit FlushQueue() method in my class to allow the caller to abandon work in my queue. Anyone have any suggestion on a threading pattern that fits my needs?

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  • java Finalize method call

    - by Rajesh Kumar J
    The following is my Class code import java.net.*; import java.util.*; import java.sql.*; import org.apache.log4j.*; class Database { private Connection conn; private org.apache.log4j.Logger log ; private static Database dd=new Database(); private Database(){ try{ log= Logger.getLogger(Database.class); Class.forName("com.mysql.jdbc.Driver"); conn=DriverManager.getConnection("jdbc:mysql://localhost/bc","root","root"); conn.setReadOnly(false); conn.setAutoCommit(false); log.info("Datbase created"); /*Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); conn=DriverManager.getConnection("jdbc:odbc:rmldsn"); conn.setReadOnly(false); conn.setAutoCommit(false);*/ } catch(Exception e){ log.info("Cant Create Connection"); } } public static Database getDatabase(){ return dd; } public Connection getConnection(){ return conn; } @Override protected void finalize()throws Throwable { try{ conn.close(); Runtime.getRuntime().gc(); log.info("Database Close"); } catch(Exception e){ log.info("Cannot be closed Database"); } finally{ super.finalize(); } } } This can able to Initialize Database Object only through getDatabase() method. The below is the program which uses the single Database connection for the 4 threads. public class Main extends Thread { public static int c=0; public static int start,end; private int lstart,lend; public static Connection conn; public static Database dbase; public Statement stmt,stmtEXE; public ResultSet rst; /** * @param args the command line arguments */ static{ dbase=Database.getDatabase(); conn=dbase.getConnection(); } Main(String s){ super(s); try{ stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); start=end; lstart=start; end=end+5; lend=end; System.out.println("Start -" +lstart +" End-"+lend); } catch(Exception e){ e.printStackTrace(); } } @Override public void run(){ try{ URL url=new URL("http://localhost:8084/TestWeb/"); rst=stmt.executeQuery("SELECT * FROM bc.cdr_calltimestamp limit "+lstart+","+lend); while(rst.next()){ try{ rst.updateInt(2, 1); rst.updateRow(); conn.commit(); HttpURLConnection httpconn=(HttpURLConnection) url.openConnection(); httpconn.setDoInput(true); httpconn.setDoOutput(true); httpconn.setRequestProperty("Content-Type", "text/xml"); //httpconn.connect(); String reqstring="<?xml version=\"1.0\" encoding=\"US-ASCII\"?>"+ "<message><sms type=\"mt\"><destination messageid=\"PS0\"><address><number" + "type=\"international\">"+ rst.getString(1) +"</number></address></destination><source><address>" + "<number type=\"unknown\"/></address></source><rsr type=\"success_failure\"/><ud" + "type=\"text\">Hello World</ud></sms></message>"; httpconn.getOutputStream().write(reqstring.getBytes(), 0, reqstring.length()); byte b[]=new byte[httpconn.getInputStream().available()]; //System.out.println(httpconn.getContentType()); httpconn.getInputStream().read(b); System.out.println(Thread.currentThread().getName()+new String(" Request"+rst.getString(1))); //System.out.println(new String(b)); httpconn.disconnect(); Thread.sleep(100); } catch(Exception e){ e.printStackTrace(); } } System.out.println(Thread.currentThread().getName()+" "+new java.util.Date()); } catch(Exception e){ e.printStackTrace(); } } public static void main(String[] args) throws Exception{ System.out.println(new java.util.Date()); System.out.println("Memory-before "+Runtime.getRuntime().freeMemory()); Thread t1=new Main("T1-"); Thread t2=new Main("T2-"); Thread t3=new Main("T3-"); Thread t4=new Main("T4-"); t1.start(); t2.start(); t3.start(); t4.start(); System.out.println("Memory-after "+Runtime.getRuntime().freeMemory()); } } I need to Close the connection after all the threads gets executed. Is there any good idea to do so. Kindly help me out in getting this work.

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  • C# Object Creation from Datatable

    - by Jonesy
    Hi Folks, Im just getting my head round C#. I've been creating classes and objects so say i created a class called Member: public class Member { public int MemberID; public string FirstName; public string LastName; public string UserName; } and i create a new object of that class by doing this: Member Billy = new Member(); Billy.UserName = "Jonesy"; Billy.FirstName = "Billy"; Billy.LastName = "Jones"; Thats all fine but what if I've queried a database and gotten back 5 members, can I create objects on the fly? Or what is the best way to store these members in memory? I've used VB.Net where I would just add them into a datatable. But I've never really done any object-oriented programming before and thought since I'm learning C sharp nows the best time to learn OOP.. Any help most appreciated! Jonesy

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  • Grails: Problem with nested associations in criteria builder

    - by Mr.B
    I have a frustrating problem with the criteria builder. I have an application in which one user has one calendar, and a calendar has many entries. Seems straightforward enough, but when I try to get the calendar entries for a given user, I can't access the user property (MissingMethodException). Here's the code: def getEntries(User user) { def entries = Entries.createCriteria().list() { calendar { user { eq("user.id", user.id) } } } } I have even tried the following variation: def getEntries(User user) { def entries = Entries.createCriteria().list() { calendar { eq("user", user) } } } That did not raise an exception, but didn't work either. Here's the relevant parts of the domain classes: class Calendar { static belongsTo = [user: User] static hasMany = [entries: Entries] ... } class User { Calendar calendar ... } class Entry { static belongsTo = [calendar: Calendar] ... } When Googling I came across a similar problem noted in early 2008: http://jira.codehaus.org/browse/GRAILS-1412 But according to that link this issue should have been solved long ago. What am I doing wrong?

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  • C++: Dependency injection, circular dependency and callbacks

    - by Jonathan
    Consider the (highly simplified) following case: class Dispatcher { public: receive() {/*implementation*/}; // callback } class CommInterface { public: send() = 0; // call } class CommA : public CommInterface { public: send() {/*implementation*/}; } Various classes in the system send messages via the dispatcher. The dispatcher uses a comm to send. Once an answer is returned, the comm relays it back to the dispatcher which dispatches it back to the appropriate original sender. Comm is polymorphic and which implementation to choose can be read from a settings file. Dispatcher has a dependency on the comm in order to send. Comm has a dependency on dispatcher in order to callback. Therefor there's a circular dependency here and I can't seem to implement the dependency injection principle (even after encountering this nice blog post).

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  • How to get the ObjectId value from MongoDB?

    - by LVarayut
    I'm using Jongo with Play framework 2, java. I added some data into my MongoDB. {"_id" : ObjectId("538dafffbf6b562617252178"), ... } However, when I fetched the ObjectId from the database, it gave me like: de.undercouch.bson4jackson.types.ObjectId@484431ff instead of 538dafffbf6b562617252178. I don't quite understand how can I get the ObjectId value. My class is defined as following: public class Product { @JsonProperty("_id") protected String id; ... public Product() { } public String getId() { return id; } public void setId(String id) { this.id = id; } } EDIT In order to fetch the data, I simply use find() function provided by Jongo as following: public static Iterable<Product> findAll(){ return products().find().as(Product.class); }

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  • Implicit typing of arrays that implement interfaces

    - by Sir Psycho
    Hi, I was under the impression that the C# compiler will implicitly type an array based off a type that they can all be implicitly converted to. The compiler generates No best type found for implicitly-typed array public interface ISomething {} public interface ISomething2 {} public interface ISomething3 {} public class Foo : ISomething { } public class Bar : ISomething, ISomething2 { } public class Car : ISomething, ISomething3 { } void Main() { var obj1 = new Foo(); var obj2 = new Bar(); var obj3 = new Car(); var objects= new [] { obj1, obj2, obj3 }; } I know that the way to correct this is to declare the type like: new ISomething [] { obj1, ...} But I'm after an under the covers type help here :-) Thanks

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  • Store in DB or not to store ?

    - by eugeneK
    There are few string lists in my web application that i don't know where to store in DB or just class. ie. I have 7 major browsers with which users enter the site. I want to save these stats thus i need to create browser column in UserLogin database. I don't want to waste space and resources so i can save full browser name in each login row. So i either need to save browserID field and hook it up with Browsers table which will store names following db normalization rules or to have sort of Dataholder abstract class which has a list of browsers from which i can retrieve browser name by it's ID... The question what should i do ? These few data lists i have contain no more than 200 items each so i think it makes sense to have them as abstract class but again i don't know whether MS-SQL will handle multiple joins so well. Think of idea when i have user with country,ip,language,browser and few more stats .. thanks

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  • String replacement problem.

    - by fastcodejava
    I want to provide some template for a code generator I am developing. A typical pattern for class is : public ${class_type} ${class_name} extends ${super_class} implements ${interfaces} { ${class_body} } Problem is if super_class is blank or interfaces. I replace extends ${super_class} with empty string. But I get extra spaces. So a class with no super_class and interfaces end up like : public class Foo { //see the extra spaces before {? ${class_body} } I know I can replace multiple spaces with single, but is there any better approach?

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  • Where is the virtual function call overhead?

    - by Semen Semenych
    Hello everybody, I'm trying to benchmark the difference between a function pointer call and a virtual function call. To do this, I have written two pieces of code, that do the same mathematical computation over an array. One variant uses an array of pointers to functions and calls those in a loop. The other variant uses an array of pointers to a base class and calls its virtual function, which is overloaded in the derived classes to do absolutely the same thing as the functions in the first variant. Then I print the time elapsed and use a simple shell script to run the benchmark many times and compute the average run time. Here is the code: #include <iostream> #include <cstdlib> #include <ctime> #include <cmath> using namespace std; long long timespecDiff(struct timespec *timeA_p, struct timespec *timeB_p) { return ((timeA_p->tv_sec * 1000000000) + timeA_p->tv_nsec) - ((timeB_p->tv_sec * 1000000000) + timeB_p->tv_nsec); } void function_not( double *d ) { *d = sin(*d); } void function_and( double *d ) { *d = cos(*d); } void function_or( double *d ) { *d = tan(*d); } void function_xor( double *d ) { *d = sqrt(*d); } void ( * const function_table[4] )( double* ) = { &function_not, &function_and, &function_or, &function_xor }; int main(void) { srand(time(0)); void ( * index_array[100000] )( double * ); double array[100000]; for ( long int i = 0; i < 100000; ++i ) { index_array[i] = function_table[ rand() % 4 ]; array[i] = ( double )( rand() / 1000 ); } struct timespec start, end; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start); for ( long int i = 0; i < 100000; ++i ) { index_array[i]( &array[i] ); } clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end); unsigned long long time_elapsed = timespecDiff(&end, &start); cout << time_elapsed / 1000000000.0 << endl; } and here is the virtual function variant: #include <iostream> #include <cstdlib> #include <ctime> #include <cmath> using namespace std; long long timespecDiff(struct timespec *timeA_p, struct timespec *timeB_p) { return ((timeA_p->tv_sec * 1000000000) + timeA_p->tv_nsec) - ((timeB_p->tv_sec * 1000000000) + timeB_p->tv_nsec); } class A { public: virtual void calculate( double *i ) = 0; }; class A1 : public A { public: void calculate( double *i ) { *i = sin(*i); } }; class A2 : public A { public: void calculate( double *i ) { *i = cos(*i); } }; class A3 : public A { public: void calculate( double *i ) { *i = tan(*i); } }; class A4 : public A { public: void calculate( double *i ) { *i = sqrt(*i); } }; int main(void) { srand(time(0)); A *base[100000]; double array[100000]; for ( long int i = 0; i < 100000; ++i ) { array[i] = ( double )( rand() / 1000 ); switch ( rand() % 4 ) { case 0: base[i] = new A1(); break; case 1: base[i] = new A2(); break; case 2: base[i] = new A3(); break; case 3: base[i] = new A4(); break; } } struct timespec start, end; clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start); for ( int i = 0; i < 100000; ++i ) { base[i]->calculate( &array[i] ); } clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end); unsigned long long time_elapsed = timespecDiff(&end, &start); cout << time_elapsed / 1000000000.0 << endl; } My system is LInux, Fedora 13, gcc 4.4.2. The code is compiled it with g++ -O3. The first one is test1, the second is test2. Now I see this in console: [Ignat@localhost circuit_testing]$ ./test2 && ./test2 0.0153142 0.0153166 Well, more or less, I think. And then, this: [Ignat@localhost circuit_testing]$ ./test2 && ./test2 0.01531 0.0152476 Where are the 25% which should be visible? How can the first executable be even slower than the second one? I'm asking this because I'm doing a project which involves calling a lot of small functions in a row like this in order to compute the values of an array, and the code I've inherited does a very complex manipulation to avoid the virtual function call overhead. Now where is this famous call overhead?

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  • java: Preferences API vs. Apache Commons Configuration

    - by Jason S
    I need to allow the user to store/load an arbitrary number of lists of objects (assume they are Serializable). Conceptually I want a data model like class FooBean { /* bean stuff here */ } class FooList { final private Set<FooBean> items = new HashSet<FooBean>(); public boolean add(FooBean item) { return items.add(item); } public boolean remove(FooBean item) { return items.remove(item); } public Collection<FooBean> getItems() { return Collections.unmodifiableSet(items); } } class FooStore { public FooStore() { /* something... uses Preferences or Commons Configuration */ } public FooList load(String key) { /* something... retrieves a FooList associated with the key */ } public void store(String key, FooList items) { /* something... saves a FooList under the given key */ } } Should I use the Preferences API or Commons Config? What's the advantages of each?

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