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• Spring/RMI server error

  - by 4herpsand7derpsago

  We have a Spring MVC web app (WAR) deploying to Tomcat (6.0.35) that launches a thread inside a separate JVM at deploy time (don't ask why - not my design) and then communicates with that thread via RMI over port 8888. Despite being totally convoluded, this was working perfectly fine up until yesterday, and now the thread is failing at startup and despite our best efforts to add logging into the mix, we are hitting a wall. This is the only exception we are able to find in the logs: Jun 12, 2012 3:11:36 AM com.ourapp.ImageController destroy SEVERE: Shutdown Error: Lookup of RMI stub failed; nested exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection refused Jun 12, 2012 3:11:37 AM org.apache.catalina.core.StandardContext listenerStop SEVERE: Exception sending context destroyed event to listener instance of class org.springframework.web.context.ContextLoaderListener java.lang.NoClassDefFoundError: org/springframework/web/context/ContextCleanupListener at org.springframework.web.context.ContextLoaderListener.contextDestroyed(ContextLoaderListener.java:80) at org.apache.catalina.core.StandardContext.listenerStop(StandardContext.java:3973) at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4577) at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1165) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590) at java.lang.Thread.run(Thread.java:662) Caused by: java.lang.ClassNotFoundException: org.springframework.web.context.ContextCleanupListener at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233) ... 12 more The ImageController is the Spring MVC Controller that is responsible for kicking off this daemon/spawned RMI thread. Based on the verbage of this error, does anybody have any idea what might be causing this "connection refused" error? Running a netstat -an | grep 8888 (this is a Linux machine) produces no output which means nothing is listening on that port. Thanks in advance for any ideas/suggestions that lead to a fix. Edit: Here's another ConnectionException we're seeing: Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at java.net.Socket.<init>(Socket.java:375) at java.net.Socket.<init>(Socket.java:189) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595) ... 74 more

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• AD - DirectoryServices: VBNET2.0 - Speaking architecture...

  - by Will Marcouiller

  I've been mandated to write an application to migrate the Active Directory access models to another environment. Here's the context: I'm stuck with VB.NET 2005 and .NET Framework 2.0; The application must use the Windows authenticated user to manage AD; The objects I have to handle are Groups, Users and OrganizationalUnits; I intend to use the Façade design pattern to provider ease of use and a fully reusable code; I plan to write a factory for each of the objects managed (group, ou, user); The use of Attributes should be useful here, I guess; As everything is about the DirectoryEntry class when accessing the AD, it seems a good candidate for generic types. Obligatory features: User creates new OUs manually; User creates new group manually; User creates new user (these users are services accounts) manually; Application reads an XML file which contains the OUs, groups and users to create; Application informs the user about the OUs, groups and users that shall be created; User specifies the domain environment where to migrate the XML input file designated objects; User makes changes if needed, and launches the task operations; Application performs required by the XML input file operations against the underlying AD as specified by the user; Application informs the user upon completion. Linear features: User fetches OUs, groups, users; User changes OUs, groups, users; User deletes OUs, groups, users; The application logs AD entries and operations performed, plus errors and exceptions; Nice-to-have features: Application rollbacks operations on error or exception. I've been working for weeks now to get acquainted with the AD and the System.DirectoryServices assembly. But I don't seem to find a way to be fully satisfied with what I'm doing and always looking for better. I have studied Bret de Smet's Linq to AD on CodePlex, but then again, I can't use it as I'm stuck with .NET 2.0, so no Linq! But I've learned about Attributes, and seen that he's working with generic types as he codes a DirectorySource class to perform the operations for OUs, groups and users. Any suggestions? Thanks for any help, code sample, ideas, architural solution, everything!

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• SaaS Architecture Question from Newbie

  - by user226767

  I have developed a number of departmental client-server applications, and am now ready to begin working on moving one of these applications to a SaaS model. I have done some basic web development, but I'm a newbie when it comes to SaaS architectures. One of the first questions that comes to mind as I try to design the architecture is the question of single vs. multi tenancy. The pros and cons of each vary significantly depending on the type of application and scale required, so I'd like to describe my application and scale needs below, and hope others can comment on how I should get started with the architecture. The client-server application currently consists of a Firebird database and a Windows application. The database contains about 20 tables containing a few thousand records in 4 primary tables, and a few hundred records in various lookup and related tables. Although the number of records is small, the size can get large, as the database can contain large BLOBS. Each customer sets up their own database and has a handful of users within the organization connected to it. When I update the db schema, a new windows application is released, and it checks the db schema and then applies the updates as needed. For the SaaS application, I am designing for 100's (not 1000's or millions) of new customers per year. My first thought was to go with a multi tenancy model to make updates easy (shut down apply the updates to one database, and then start up). On the other hand, a single tenancy model would provide a means to roll updates out to a group of customers at a time, and spread the risk of data corruption - i.e. if something goes wrong with a database, it will impact one customer instead of all customers. With this idea, I was thinking of having a single web front-end which would connect to a single customer database upon login. Thus, when a new customer creates an account, a new database would be created (each customer would have their own db with multiple users as needed for the customer). In this model, a db update would require either a process to go through each db to apply schema changes, or a trigger upon logging in to initiate a schema update similar to the client-server model currently in use. Can anyone point me to information for similar applications which have been ported from client-server to SaaS? Or provide any pointers to consider? Basically I'm looking for architecture examples of taking a departmental application and making it available as a self service website for multiple customers. Thanks for any suggestions, resources, etc.

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• Would someone mind giving suggestions for this new assembly language?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo save Store load Retrieve L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller exit End the program print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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• android zxing intentintegrator

  - by cristi _b

  I've written the following code that works fine if you decide to scan a QR code (using zxing) and store it in private storage but in case you decide to cancel scanning, it crashes and the file previously stored content disappears. I think it might be a design error, not sure why. Below is relevant code ... /** * menu generation */ @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.menu, menu); return true; } /** * menu handling */ @Override public boolean onOptionsItemSelected(MenuItem item) { Context context = getApplicationContext(); Toast toast = Toast.makeText(context, "", Toast.LENGTH_LONG); toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); switch (item.getItemId()) { case R.id.qrScan: IntentIntegrator integrator = new IntentIntegrator(this); integrator.initiateScan(); return true; case R.id.qrReset: File dir = getFilesDir(); File file = new File(dir, qrCodeFile); boolean deleted = file.delete(); return true; case R.id.appClose: this.finish(); return true; default: return super.onOptionsItemSelected(item); } } ... public void onActivityResult(int requestCode, int resultCode, Intent intent) { IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent); Context context = getApplicationContext(); Toast toast = Toast.makeText(context, "", Toast.LENGTH_SHORT); if (scanResult != null) { FileOutputStream fos = null; CharSequence text = scanResult.getContents(); try { fos = openFileOutput(qrCodeFile, Context.MODE_PRIVATE); try { fos.write(text.toString().getBytes()); fos.close(); toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Code saved"); toast.show(); } catch (IOException ex) { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Invalid code"); toast.show(); Logger.getLogger(MainActivity.class.getName()).log(Level.SEVERE, null, ex); } } catch (FileNotFoundException ex) { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Error while saving"); toast.show(); Logger.getLogger(MainActivity.class.getName()).log(Level.SEVERE, null, ex); } } else { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Invalid code"); toast.show(); } }

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• What Can I Do To One Of My Team Number (Good Friend As Well) Who Lost His Passion.

  - by skyflyer

  It seems this question is not program related, but there are lot of similar questions. So please bear with me! By the way, I am programmer and my team is also charging a software project. And SO is the only place which solved me lot of thorny troubles!THANK YOU GUYS! I joined my company with him years ago. At that time he was quite passionate on his job which is a front-end development. He gave us lot of useful suggestions concerning his work like design. And I believed he was a smart guy. I believe he still is smart too by the way. One years later, however, he seemed lost his passion and fooling around every day, did not care about his work any more and produced poorwork. Even worse he literally stopped learning new skills and honing his work related skills. For me it is horrible, we got to keep abreast with new technology development, otherwise we will be throw out. Since we were just coworkers, I did not care about it too much except mentioned my thoughts several times. But last month, we resembled a new group and assigned very important project. And I am the team leader, sadly! My boss gave me lot of support and expectation as well. I did a pretty good job before and I am very optimism to our future. But as a team, if my team does not work hard, we will be doomed to failure no matter how hard I work and push. In order to revitalize his passion, I tried couple of ways like talking to him about my concern and my boss's angry. I offered his new task which is quite new to him. I even persuaded my boss to give him new incentive package. But all of them knocked wall. His reaction was just he did not care. Even worse he did not want to talk about his situation. I want to be hard on him, but since we are friends and coworkers, I really can not see it will work. Even it works, I can not so quickly change my self from friend and coworker into manager. As a novice in management, I am really overwhelmed! I do not want get him fired, we are friends and I do not see him fired as my team number. What can I do? Thank you guys!

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• decorator pattern

  - by vbNewbie

  I have a program that converts currency using a specific design pattern. I now need to take my converted result and using the decorator pattern allow the result to be converted to 3 different formats: 1 - exponential notation, rounded to 2 decimal points. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace Converter { public partial class Form1 : Form { // Setup Chain of Responsibility Handler h1 = new USDHandler(); Handler h2 = new CADHandler(); Handler h3 = new AUDHandler(); public string reqCurName; public int reqAmt; public string results; public string requestID; public Form1() { InitializeComponent(); h1.SetSuccessor(h2); h2.SetSuccessor(h3); } // "Handler" private void button1_Click_1(object sender, EventArgs e) { reqCurName = txtInput.Text; reqAmt = Convert.ToInt32(txtAmt.Text.ToString()); results = h1.HandleRequest(reqCurName, reqAmt); if (results != "") { lblResult.Text = results; lblResult.Visible = true; } } abstract class Handler { protected Handler successor; public string retrn; public void SetSuccessor(Handler successor) { this.successor = successor; } public abstract string HandleRequest(string requestID, int reqAmt); } // "USD Handler" class USDHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "USD") { retrn = "Request handled by " + this.GetType().Name + " \nConversion from Euro to USD is " + reqAmt/0.630479; return (retrn); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (retrn); } } // "CAD Handler" class CADHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "CAD") { retrn = "Request handled by " + this.GetType().Name + " \nConversion from Euro to CAD is " + reqAmt /0.617971; return (retrn); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (retrn); } } // "AUD Handler" class AUDHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "AUD") { requestID = "Request handled by " + this.GetType().Name + " \nConversion from Euro to AUD is " + reqAmt / 0.585386; return (requestID); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (requestID); } } } }

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• Why does the rename() syscall prohibit moving a directory that I can't write to a different director

  - by Daniel Papasian

  I am trying to understand why this design decision was made with the rename() syscall in 4.2BSD. There's nothing I'm trying to solve here, just understand the rationale for the behavior itself. 4.2BSD saw the introduction of the rename() syscall for the purpose of allowing atomic renames/moves of files. From 4.3BSD-Reno/src/sys/ufs/ufs_vnops.c: /* * If ".." must be changed (ie the directory gets a new * parent) then the source directory must not be in the * directory heirarchy above the target, as this would * orphan everything below the source directory. Also * the user must have write permission in the source so * as to be able to change "..". We must repeat the call * to namei, as the parent directory is unlocked by the * call to checkpath(). */ if (oldparent != dp->i_number) newparent = dp->i_number; if (doingdirectory && newparent) { VOP_LOCK(fndp->ni_vp); error = ufs_access(fndp->ni_vp, VWRITE, tndp->ni_cred); VOP_UNLOCK(fndp->ni_vp); So clearly this check was added intentionally. My question is - why? Is this behavior supposed to be intuitive? The effect of this is that one cannot move a directory (located in a directory that one can write) that one cannot write to another directory that one can write to atomically. You can, however, create a new directory, move the links over (assuming one has read access to the directory), and then remove one's write bit on the directory. You just can't do so atomically. % cd /tmp % mkdir stackoverflow-question % cd stackoverflow-question % mkdir directory-1 % mkdir directory-2 % mkdir directory-1/directory-i-cant-write % echo "foo" > directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write % mv directory-1/directory-i-cant-write directory-2 mv: rename directory-1/directory-i-cant-write to directory-2/directory-i-cant-write: Permission denied We now have a directory I can't write with contents I can't read that I can't move atomically. I can, however, achieve the same effect non-atomically by changing permissions, making the new directory, using ln to create the new links, and changing permissions. (Left as an exercise to the reader) . and .. are special cased already, so I don't particularly buy that it is intuitive that if I can't write a directory I can't "change .." which is what the source suggests. Is there any reason for this besides it being the perceived correct behavior by the author of the code? Is there anything bad that can happen if we let people atomically move directories (that they can't write) between directories that they can write?

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• AD-DirectoryServices: .NET2.0 - Speaking architecture, approach and best practices... Suggestions?

  - by Will Marcouiller

  I've been mandated to write an application to migrate the Active Directory access models to another environment. Here's the context: I'm stuck with VB.NET 2005 and .NET Framework 2.0; The application must use the Windows authenticated user to manage AD; The objects I have to handle are Groups, Users and OrganizationalUnits; I intend to use the Façade design pattern to provider ease of use and a fully reusable code; I plan to write a factory for each of the objects managed (group, ou, user); The use of Attributes should be useful here, I guess; As everything is about the DirectoryEntry class when accessing the AD, it seems a good candidate for generic types. Obligatory features: User creates new OUs manually; User creates new group manually; User creates new user (these users are services accounts) manually; Application reads an XML file which contains the OUs, groups and users to create; Application informs the user about the OUs, groups and users that shall be created; User specifies the domain environment where to migrate the XML input file designated objects; User makes changes if needed, and launches the task operations; Application performs required by the XML input file operations against the underlying AD as specified by the user; Application informs the user upon completion. Linear features: User fetches OUs, groups, users; User changes OUs, groups, users; User deletes OUs, groups, users; The application logs AD entries and operations performed, plus errors and exceptions; Nice-to-have features: Application rollbacks operations on error or exception. I've been working for weeks now to get acquainted with the AD and the System.DirectoryServices assembly. But I don't seem to find a way to be fully satisfied with what I'm doing and always looking for better. I have studied Bret de Smet's Linq to AD on CodePlex, but then again, I can't use it as I'm stuck with .NET 2.0, so no Linq! But I've learned about Attributes, and seen that he's working with generic types as he codes a DirectorySource class to perform the operations for OUs, groups and users. I have been able to add groups to the AD; I have been able to add users to the AD; The created user is automatically disabled? I seem to get confused with the use of a LDAP path to add objects. For instance, one needs two instances of a System.DirectoryServices.DirectoryEntry class to add a group, for instance. Why this? Any suggestions? Thanks for any help, code sample, ideas, architural solution, everything!

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• Database Logon Error in crystal report

  - by yasar arafat

  am really very dumb as this problem is being answered so many times but eally its above my head. i dont have any idea about working with crystal reports or asp.net but due to some reason i have to work on it. after trying very hard i m able to design on crystal report connecting it with mysql database. now when i see in the crystalreport preview i am able to see the report and the data ![enter image description here][1] but when i try to run it on server it says database logon failed![enter image description here][2] now i really dont know what to do i am pasting my aspx and aspx.vb code here and please repley in english not computer language believe me i m super dumb enter code here aspx codes <%@ Page Title="" Language="VB" MasterPageFile="~/Master/Site.master"AutoEventWireup="false" CodeFile="ManHourCostExpenditure.aspx.vb" Inherits="ManHourCostExpenditure" %> <%@ Register assembly="CrystalDecisions.Web, Version=13.0.2000.0, Culture=neutral, PublicKeyToken=692fbea5521e1304" namespace="CrystalDecisions.Web" tagprefix="CR" %> <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server"> <CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" AutoDataBind="True" EnableDatabaseLogonPrompt="False" EnableParameterPrompt="False" GroupTreeImagesFolderUrl="" Height="1202px" ReportSourceID="CrystalReportSource1" ToolbarImagesFolderUrl="" ToolPanelView="None" ToolPanelWidth="200px" Width="903px" BorderColor="#660033" BorderStyle="Solid" BorderWidth="1px" HasCrystalLogo="False" /> <CR:CrystalReportSource ID="CrystalReportSource1" runat="server"> <Report FileName="CrDiscProjManHoursActVsEst.rpt"> </Report> </CR:CrystalReportSource> </asp:Content> aspxdotvb codes Imports CrystalDecisions.CrystalReports.Engine Imports CrystalDecisions.Shared Imports CrystalDecisions.Enterprise Imports CrystalDecisions.ReportSource Imports CrystalDecisions.Web Imports CrystalDecisions.Windows.Forms Imports MySql Imports MySql.Data Imports MySql.Data.MySqlClient Imports System.Collections Imports System.Collections.Generic Imports System.Text Imports CrystalDecisions Imports CrystalDecisions.CrystalReports Imports CrystalReportsReportDefModelLib Partial Class ManHourCostExpenditure Inherits System.Web.UI.Page Dim CrRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim StrConn As String = "SERVER=localhost;DATABASE=fluor;UID=root; PWD=root;" Dim Conn As New MySqlConnection(StrConn) Conn.Open() Dim CrRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument 'Session.Add("REPORT_KEY", CrRpt) CrRpt.Load(Server.MapPath("CrManHourCostExpenditure.rpt")) CrRpt.PrintOptions.PaperOrientation = PaperOrientation.Landscape 'If IsPostBack Then ' CrRpt = CType(Session.Item("REPORT_KEY"), Group) ' CrystalReportViewer1.ReportSource = CrRpt 'End If CrystalReportViewer1.ReportSource = CrRpt 'CrystalReportViewer1.DataBind() CrystalReportViewer1.RefreshReport() Conn.Close() 'CrRpt.Close() 'CrRpt.Dispose() End Sub Protected Sub Page_Unload(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Unload 'CrystalReportViewer1.ReportSource.Close() CrRpt.Close() CrRpt.Dispose() End Sub 'Protected Sub CrystalReportViewer1_Unload(ByVal sender As Object, ByVal e As System.EventArgs) Handles CrystalReportViewer1.Unload ' CrRpt.Close() ' CrRpt.Dispose() 'End Sub End Class please help me. thanks in advance.... yasir

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• How do we, as a community, help encourage programming in public schools? (Or state Schools for the U

  - by NoMoreZealots

  PRIMARY MOTIVATION My office gets involved with the "First Robotics" competitions and one thing that lingers year to year is the students typically have no preparation for doing even simple programming as part of the public schools system. While the science classes provide some basic grasp of mechanical and electrical concepts, by in large computer programming gets no coverage from the curriculum. (This my be different in other areas of the country/world.) What makes it worse is there is only a short period of time you have to prepare the student's and help them design the robot. Talking to some professors from local colleges, it's a problem because you can't assume even the most basic understanding for freshman CS majors. Languages like Python, Lua and BASIC are simple enough for at least high school level students, if not younger. SCOPE So how do you get public schools to support a programming, at least to the level of "Try it in BASIC" examples that used to be at the end of a chapter in my Algebra book? At least enough to prepare them for event's such as the FIRST Robotic competitions. Which the primary objectives are to teach problem solving and team work, and to possible foster an interest in Math, Science and Engineering in general. (Not force feed to them, as some people her seem to be implying.) Edit: Why teach kids: (Since 2000 CS enrollment in US colleges has decreased by 70% while college enrollment has increased, this is a PROBLEM.) Saying there is no value in teaching someone programming in Jr./High school because they might think "they know programming." Is like saying there's no value in teaching High school science and physics, because they might decide they "know physics." Leading to abuse like: "I passed a high school physics class, I'm going to develop a Unified Quantum Gravitational Theory." Better Prepared students are better students. Instead it would allows college programs to raise the bar on the entry level courses, allowing students to be weeded out based on their understanding of more advanced material. Plus people who did poorly in that in topic in High school aren't as likely to say "I think there's money in computer's so I'll computer science." Plus if people take it in high school and decide THEN that it's not for them, it's better than them wasting their money to PAY a college to figure that out. The result is that people who take the degree are more likely to succeed and be there for the RIGHT reasons. (i.e. It's what they REALLY want to do. And that's REALLY the key to being good at anything.) Programming is like anything else, the more practice and genuine interest you have the better you get. If you start them later, they get less practice. The earlier give them the opportunity to start, the more practice they will get. All other things equal, the more practice the better the programmer.

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• WPF binding behaviour different when bound property is declared as interface vs class type?

  - by Jay

  This started with weird behaviour that I thought was tied to my implementation of ToString(), and I asked this question: http://stackoverflow.com/questions/2916068/why-wont-wpf-databindings-show-text-when-tostring-has-a-collaborating-object It turns out to have nothing to do with collaborators and is reproducible. When I bind Label.Content to a property of the DataContext that is declared as an interface type, ToString() is called on the runtime object and the label displays the result. When I bind TextBlock.Text to the same property, ToString() is never called and nothing is displayed. But, if I change the declared property to a concrete implementation of the interface, it works as expected. Is this somehow by design? If so, any idea why? To reproduce: Create a new WPF Application (.NET 3.5 SP1) Add the following classes: public interface IFoo { string foo_part1 { get; set; } string foo_part2 { get; set; } } public class Foo : IFoo { public string foo_part1 { get; set; } public string foo_part2 { get; set; } public override string ToString() { return foo_part1 + " - " + foo_part2; } } public class Bar { public IFoo foo { get { return new Foo {foo_part1 = "first", foo_part2 = "second"}; } } } Set the XAML of Window1 to: <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <StackPanel> <Label Content="{Binding foo, Mode=Default}"/> <TextBlock Text="{Binding foo, Mode=Default}"/> </StackPanel> </Window> in Window1.xaml.cs: public partial class Window1 : Window { public Window1() { InitializeComponent(); DataContext = new Bar(); } } When you run this application, you'll see the text only once (at the top, in the label). If you change the type of foo property on Bar class to Foo (instead of IFoo) and run the application again, you'll see the text in both controls.

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• Choosing the right .NET architecture. WCF? WPF/Forms, ASP.NET (MVC)?

  - by Tommy Jakobsen

  I’m in the situation that I have to design and implement a rather big system from the bottom. I’m having some (a lot actually) questions about the architecture that I would like your comments and thoughts on. I don’t hope that I’ve written too much here, but I wanted to give you all an idea of what the system is. Quick info about the applications, read if you want: I can’t share much detail about the project, but basically it’s a system where we offer our customer a service to manage their users. We have a hotline where the users call and our hotline uses an (windows) application (intranet) to manage the user’s data, etc. The customer also has a web application where they can see reports, information about their business and users, and the ability to modify their data. Modifying data is not just user data like address and so, but also information about the products/services the user has, which can be complicated. The applications will be built on Microsoft .NET Framework 4, with a MS SQL Server 2008 database. There will be a few applications that have to access this database, such as: Intranet application (used by us and our hotline) Customer web application type 1 Customer web application type 2 Customer web application type n different applications) … Now my big problem is what .NET parts I should use for such a system. For the “backend” I’ve considered using Windows Communication Foundation: Would WCF be a good choice? The intranet application will be an application that has to edit lots of records in the database. It has to be easy to navigate using the keyboard (fast to work with). Has a feature such as “find customer, find that, lookup this, choose this and update that”. What would be the best choice to develop this application in? Would it be WPF or good old Windows Forms? I don’t need all of the fancy graphics features in WPF, like 3D, but the application has to look nice (maybe something like the new Visual Studio/Office tools). And the same question goes for the web pages. They have much the same work to do, but not as many features as the intranet application, and not the same amount of data (much less). That is my questions for now. I’m hoping to get a discussion going that will open my eyes to some of these technologies, helping me decide architecture to go with. I would like to say thanks in advance, and let you all know that any thoughts will be much appreciated.

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• php array code with regular expressions

  - by user551068

  there are few mistakes which it is showing as Warning: preg_match() [function.preg-match]: Delimiter must not be alphanumeric or backslash in array 4,9,10,11,12... can anyone resolve them <?PHP $hosts = array( array("ronmexico.kainalopallo.com/","beforename=$F_firstname%20$F_lastname&gender=$F_gender","Your Ron Mexico Name is ","/the ultimate disguise, is <u><b>([^<]+)<\/b><\/u>/s"), array("www.fjordstone.com/cgi-bin/png.pl","gender=$F_gender&submit=Name%20Me","Your Pagan name is ","/COLOR=#000000 SIZE=6> *([^<]*)<\/FONT>/"), array("rumandmonkey.com/widgets/toys/mormon/index.php","gender=$F_gender&firstname=$F_firstname&surname=$F_lastname","Your Mormon Name is ","/<p>My Mormon name is <b>([^<]+)<\/b>!<br \/>/s"), array("cyborg.namedecoder.com/index.php","acronym=$F_firstname&design=edox&design_click-edox.x=0&design_click-edox.y=0&design_click-edox=edo","","Your Cyborg Name is ","/<p>([^<]+)<\/p>/"), array("rumandmonkey.com/widgets/toys/namegen/10/","nametype=$brit&page=2&id=10&submit=God%20save%20the%20Queen!&name=$F_firstname%20$F_lastname","Your Very British Name is ","/My very British name is \&lt\;b\&gt;([^&]+)\&lt;\/b\&gt;\.\&lt;br/"), array("blazonry.com/name_generator/usname.php","realname=$F_firstname+$F_lastname&gender=$F_gender","Your U.S. Name is ","/also be known as <font size=\'\+1\'><b>([^<]+)<\/b>/s"), array("www.spacepirate.org/rogues.php","realname=$F_firstname%20$F_lastname&formentered=Yes&submit=Arrrgh","Your Space Pirate name is ","/Your pirate name is <font size=\'\+1\'><b>([^<]+)<\/b><\/font>/s"), array("rumandmonkey.com/widgets/toys/ghetto/","firstname=$F_firstname&lastname=$F_lastname","Your Ghetto Name is ","/<p align=\"center\" style=\"font-size: 36px\">\s*<br \/>\s*([^<]*)<br \/>/"), array("www.emmadavies.net/vampire/default.aspx","mf=$emgender&firstname=$F_firstname&lastname=$F_lastname&submit=Find+My+Vampire+Name","","Your Vampire Name is ","/<i class=\"vampirecontrol vampire name\">([^<]*)<\/i>/"), array("www.emmadavies.net/fairy/default.aspx","mf=$emgender&firstname=$F_firstname&lastname=$F_lastname&submit=Seek+Fairy","","Your Fairy Name is ","/<i class=\'ng fairy name\'>([^<]*)<\/i>/"), array("www.irielion.com/israel/reggaename.html","phase=3&oldname=$F_firstname%20$F_lastname&gndr=$reggender","","Your Rasta Name is ","/Yes I, your irie new name is ([^\n]*)\n/"), array("www.ninjaburger.com/fun/games/ninjaname/ninjaname.php","realname=$F_firstname+$F_lastname","Your Ninja Burger Name is ","/<BR>Ninja Burger ninja name will be<BR><BR><FONT SIZE=\'\+1\'>([^<]*)<\/FONT>/"), array("gangstaname.com/pirate_name.php","sex=$F_gender&name=$F_firstname+$F_lastname","Your Pirate Name is ","/<p><strong>We\'ll now call ye:<\/strong><\/p> *<h2 class=\"newName\">([^<]*)<\/h2>/"), array("www.xach.com/nerd-name/","name=$F_firstname+$F_lastname&gender=$F_gender","Your Nerd Name is ","/<p><div align=center class=\"nerdname\">([^<]*)<\/div>/"), array("rumandmonkey.com/widgets/toys/namegen/5941/","page=2&id=5941&nametype=$dj&name=$F_firstname+$F_lastname","Your DJ Name is ","/My disk spinnin nu name is &lt\;b&gt\;([^<]*)&lt\;\/b&gt\;\./"), array("pizza.sandwich.net/poke/pokecgi.cgi","name=$F_firstname%20$F_lastname&color=black&submit=%20send%20","Your Pokename is ","/Your Pok&eacute;name is: <h1>([^<]*)<\/h1>/") ); return $hosts; ?>

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• Bogus WPF / XAML errors in Visual Studio 2010

  - by epalm

  There are bogus errors hanging around, but at runtime everything works. Right now, I'm getting Cannot locate resource 'img/icons/silk/arrow_refresh.png'. I've got a simple UserControl called ImageButton (doesn't everyone?): <UserControl x:Class="WinDispatchClientWpf.src.controls.ImageButton" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d"> <Button Name="btnButton" Click="btnButton_Click"> <StackPanel Orientation="Horizontal"> <Image Name="btnImage" Stretch="None" /> <TextBlock Name="btnText" /> </StackPanel> </Button> </UserControl> Which does what you'd expect: [ContentProperty("Text")] public partial class ImageButton : UserControl { public String Image { set { btnImage.Source = GuiUtil.CreateBitmapImage(value); } } public String Text { set { btnText.Text = value; } } public double Gap { set { btnImage.Margin = new Thickness(0, 0, value, 0); } } public bool ToolBarStyle { set { if (value) { btnButton.Style = (Style)FindResource(ToolBar.ButtonStyleKey); } } } public bool IsCancel { set { btnButton.IsCancel = value; } } public bool IsDefault { set { btnButton.IsDefault = value; } } public event RoutedEventHandler Click; public ImageButton() { InitializeComponent(); } private void btnButton_Click(object sender, RoutedEventArgs e) { if (Click != null) { Click(sender, e); } } } Where CreateBitmapImage is the following: public static BitmapImage CreateBitmapImage(string imagePath) { BitmapImage icon = new BitmapImage(); icon.BeginInit(); icon.UriSource = new Uri(String.Format("pack://application:,,,/{0}", imagePath)); icon.EndInit(); return icon; } I can't see the design view of any xaml file that uses an ImageButton like such: <Window foo="bar" xmlns:wpfControl="clr-namespace:MyProj.src.controls"> <Grid> <wpfControl:ImageButton ToolBarStyle="True" Gap="3" Click="btnRefresh_Click" Text="Refresh" Image="img/icons/silk/arrow_refresh.png" /> </Grid> </Window> Why is VS complaining?

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• Adding NavigationControl to a TabBar Application containing UITableViews

  - by kungfuslippers

  Hi, I'm new to iPhone dev and wanted to get advice on the general design pattern / guide for putting a certain kind of app together. I'm trying to build a TabBar type application. One of the tabs needs to display a TableView and selecting a cell from within the table view will do something else - maybe show another table view or a web page. I need a Navigation Bar to be able to take me back from the table view/web page. The approach I've taken so far is to: Create an app based around UITabBarController as the rootcontroller i.e. @interface MyAppDelegate : NSObject <UIApplicationDelegate> { IBOutlet UIWindow *window; IBOutlet UITabBarController *rootController; } Create a load of UIViewController derived classes and associated NIBs and wire everything up in IB so when I run the app I get the basic tabs working. I then take the UIViewController derived class and modify it to the following: @interface MyViewController : UIViewController<UITableViewDataSource, UITableViewDelegate> { } and I add the delegate methods to the implementation of MyViewController - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 2; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } if (indexPath.row == 0) { cell.textLabel.text = @"Mummy"; } else { cell.textLabel.text = @"Daddy"; } return cell; } Go back to IB , open MyViewController.xib and drop a UITableView onto it. Set the Files Owner to be MyViewController and then set the delegate and datasource of the UITableView to be MyViewController. If I run the app now, I get the table view appearing with mummy and daddy working nicely. So far so good. The question is how do I go about incorporating a Navigation Bar into my current code for when I implement: - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath() { // get row selected NSUInteger row = [indexPath row]; if (row == 0) { // Show another table } else if (row == 1) { // Show a web view } } Do I drop a NavigationBar UI control onto MyControllerView.xib ? Should I create it programmatically? Should I be using a UINavigationController somewhere ? I've tried dropping a NavigationBar onto my MyControllerView.xib in IB but its not shown when I run the app, only the TableView is displayed.

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• How to initiate chatting between two clients and two clients only, using applets and servlets?

  - by mithun1538

  Hello everyone, I first need to apologize for my earlier questions. (You can check my profile for them)They seemed to ask more questions than give answers. Hence, I am laying down the actual question that started all them absurd questions. I am trying to design a chat applet. Till now, I have coded the applet, servlet and communication between the applet and the servlet. The code in the servlet side is such that I was able to establish chatting between clients using the applets, but the code was more like a broadcast all feature, i.e. all clients would be chatting with each other. That was my first objective when I started designing the chat applet. The second step is chatting between only two specific users, much like any other chat application we have. So this was my idea for it: I create an instance of the servlet that has the 'broadcast-all' code. I then pass the address of this instance to the respective clients. 2 client applets use the address to then chat. Technically the code is 'broadcast-all', but since only 2 clients are connected to it, it gives the chatting between two clients feature. Thus, groups of 2 clients have different instances of the same servlet, and each instance handles chatting between two clients at a max. However, as predicted, the idea didn't materialize! I tried to create an instance of the servlet but the only solution for that was using sessions on the servlet side, and I don't know how to use this session for later communications. I then tried to modify my broadcast-all code. In that code, I was using classes that implemented Observer and Observable interfaces. So the next idea that I got was: Create a new object of the Observable class(say class_1). This object be common to 2 clients. 2 clients that wish to chat will use same object of the class_1. 2 other clients will use a different object of class_1. But the problem here lies with the class that implements the Observer interface(say class_2). Since this has observers monitoring the same type of class, namely class_1, how do I establish an observer monitoring one object of class_1 and another observer monitoring another object of the same class class_1 (Because notifyObservers() would notify all the observers and I can't assign a particular observer to a particular object)? I first decided to ask individual problems, like how to create instances of servlets, using objects of observable and observer and so on in stackoverflow... but I got confused even more. Can anyone give me an idea how to establish chatting between two clients only?(I am using Http and not sockets or RMI). Regards, Mithun. P.S. Thanks to all who replied to my previous (absurd) queries. I should have stated the purpose earlier so that you guys could help me better.

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• On Mac, two jpg's whose color should match do not

  - by Tim

  So I'm designing a myspace page and I have two images, one is a repeating bg image, and another is an image which loads on a layer above it, which acts as a header/masthead. For some reason, on Macs only, and only in the browser (tested in safari and ff), the masthead renders slightly darker than the repeating bg image, creating this color inconsistency. The block that extends up behind the album artwork is a solid box made with css which blocks some of myspace's standard content. It actually renders as the proper color, blending in well with the bottom portion of this image, which is the repeating part of the background, but becomes noticeable as it extends up, over the masthead, which is darker than it should be. Both images where created in GIMP and saved as jpg's using, as far as i can tell, the same settings. Here's the pic of what is going on: Screenshot - Click Me!!! Here is the code which controls this part of the design. <div class="masthead"><span></span></div> .masthead {width: 1600px; height: 1940px; background-image:url(http://www.sourtricks.com/myspace/bdww/myspace_bg09.jpg); position: absolute; margin-left: -800px; left: 50%; top: 0px; z-index: -1; overflow-x: hidden;} body.bodyContent{ margin: 0 !important; padding: 0 !important; background-color: 000000 !important; font-size: 1px; background-image: url(http://www.sourtricks.com/myspace/bdww/bg_repeat05.jpg); background-position: center bottom; _background-position: right bottom; background-attachment: scroll; background-repeat: repeat-y; z-index: -2; overflow-x: hidden; font-family: arial, sans-serif !important; } Any help would be much, much, much appreciated. Thanks for your time, Tim

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• What Amazon S3 .NET Library is most useful and efficient?

  - by Geo

  There are two main open source .net Amazon S3 libraries. Three Sharp LitS3 I am currently using LitS3 in our MVC demo project, but there is some criticism about it. Has anyone here used both libraries so they can give an objective point of view. Below some sample calls using LitS3: On demo controller: private S3Service s3 = new S3Service() { AccessKeyID = "Thekey", SecretAccessKey = "testing" }; public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; return View("Index",s3.GetAllBuckets()); } On demo view: <% foreach (var item in Model) { %> <p> <%= Html.Encode(item.Name) %> </p> <% } %> EDIT 1: Since I have to keep moving and there is no clear indication of what library is more effective and kept more up to date, I have implemented a repository pattern with an interface that will allow me to change library if I need to in the future. Below is a section of the S3Repository that I have created and will let me change libraries in case I need to: using LitS3; namespace S3Helper.Models { public class S3Repository : IS3Repository { private S3Service _repository; #region IS3Repository Members public IQueryable<Bucket> FindAllBuckets() { return _repository.GetAllBuckets().AsQueryable(); } public IQueryable<ListEntry> FindAllObjects(string BucketName) { return _repository.ListAllObjects(BucketName).AsQueryable(); } #endregion If you have any information about this question please let me know in a comment, and I will get back and edit the question. EDIT 2: Since this question is not getting attention, I integrated both libraries in my web app to see the differences in design, I know this is probably a waist of time, but I really want a good long run solution. Below you will see two samples of the same action with the two libraries, maybe this will motivate some of you to let me know your thoughts. WITH THREE SHARP LIBRARY: public IQueryable<T> FindAllBuckets<T>() { List<string> list = new List<string>(); using (BucketListRequest request = new BucketListRequest(null)) using (BucketListResponse response = service.BucketList(request)) { XmlDocument bucketXml = response.StreamResponseToXmlDocument(); XmlNodeList buckets = bucketXml.SelectNodes("//*[local-name()='Name']"); foreach (XmlNode bucket in buckets) { list.Add(bucket.InnerXml); } } return list.Cast<T>().AsQueryable(); } WITH LITS3 LIBRARY: public IQueryable<T> FindAllBuckets<T>() { return _repository.GetAllBuckets() .Cast<T>() .AsQueryable(); }

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• Rails. Putting update logic in your migrations

  - by Daniel Abrahamsson

  A couple of times I've been in the situation where I've wanted to refactor the design of some model and have ended up putting update logic in migrations. However, as far as I've understood, this is not good practice (especially since you are encouraged to use your schema file for deployment, and not your migrations). How do you deal with these kind of problems? To clearify what I mean, say I have a User model. Since I thought there would only be two kinds of users, namely a "normal" user and an administrator, I chose to use a simple boolean field telling whether the user was an adminstrator or not. However, after I while I figured I needed some third kind of user, perhaps a moderator or something similar. In this case I add a UserType model (and the corresponding migration), and a second migration for removing the "admin" flag from the user table. And here comes the problem. In the "add_user_type_to_users" migration I have to map the admin flag value to a user type. Additionally, in order to do this, the user types have to exist, meaning I can not use the seeds file, but rather create the user types in the migration (also considered bad practice). Here comes some fictional code representing the situation: class CreateUserTypes < ActiveRecord::Migration def self.up create_table :user_types do |t| t.string :name, :nil => false, :unique => true end #Create basic types (can not put in seed, because of future migration dependency) UserType.create!(:name => "BASIC") UserType.create!(:name => "MODERATOR") UserType.create!(:name => "ADMINISTRATOR") end def self.down drop_table :user_types end end class AddTypeIdToUsers < ActiveRecord::Migration def self.up add_column :users, :type_id, :integer #Determine type via the admin flag basic = UserType.find_by_name("BASIC") admin = UserType.find_by_name("ADMINISTRATOR") User.all.each {|u| u.update_attribute(:type_id, (u.admin?) ? admin.id : basic.id)} #Remove the admin flag remove_column :users, :admin #Add foreign key execute "alter table users add constraint fk_user_type_id foreign key (type_id) references user_types (id)" end def self.down #Re-add the admin flag add_column :users, :admin, :boolean, :default => false #Reset the admin flag (this is the problematic update code) admin = UserType.find_by_name("ADMINISTRATOR") execute "update users set admin=true where type_id=#{admin.id}" #Remove foreign key constraint execute "alter table users drop foreign key fk_user_type_id" #Drop the type_id column remove_column :users, :type_id end end As you can see there are two problematic parts. First the row creation part in the first model, which is necessary if I would like to run all migrations in a row, then the "update" part in the second migration that maps the "admin" column to the "type_id" column. Any advice?

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• CSS - changing the font color for a from select option in firefox

  - by Mick

  I'm building a website for my church, and I'm teaching myself all about web design along the way. http://www.wilmingtonchurchofgod.org/contact_us.html is the link where you can see my issue. If you look at that page in firefox, and you click the select part of the form (next to, "Who would you like to contact?") you will see that when you hover over a choice, the font is white. I have tried various things to fix this, but can't find a solution. This seems to be specific to Firefox. Here is the relevant CSS. input, textarea, select, option{ padding: 6px; border: solid 1px #E5E5E5; outline: 0; font: normal 13px/100% Verdana, Tahoma, sans-serif; width: 200px; background: #FFFFFF url(images/from-grad.jpg) left top repeat-x; background: -webkit-gradient(linear, left top, left 25, from(#FFFFFF), color-stop(4%, #EEEEEE), to(#FFFFFF)); background: -moz-linear-gradient(top, #FFFFFF, #EEEEEE 1px, #FFFFFF 25px); box-shadow: rgba(0,0,0, 0.15) 0px 0px 8px; -moz-box-shadow: rgba(0,0,0, 0.15) 0px 0px 8px; -webkit-box-shadow: rgba(0,0,0, 0.15) 0px 0px 8px; } option{ padding:0px; } textarea { width: 400px; max-width: 400px; height: 150px; line-height: 150%; } input:hover, textarea:hover, input:focus, textarea:focus{ border-color: #C9C9C9; -webkit-box-shadow: rgba(0, 0, 0, 0.15) 0px 0px 8px; -moz-box-shadow: rgba(0,0,0, 0.15) 0px 0px 8px; } option:hover, option:focus, select:hover, select:focus { color: black; border-color: #C9C9C9; -webkit-box-shadow: rgba(0, 0, 0, 0.15) 0px 0px 8px; -moz-box-shadow: rgba(0,0,0, 0.15) 0px 0px 8px; } Another side note is that I can't get any background gradient at all to show up on Google Chome (yet it does on Safari and they are supposed to use the same kit?) Any help with these two things would be greatly appreciated.

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• Ignore order of elements using xs:extension

  - by Peter Lang

  How can I design my xsd to ignore the sequence of elements? <root> <a/> <b/> </root> <root> <b/> <a/> </root> I need to use extension for code generation reasons, so I tried the following using all: <?xml version="1.0" encoding="UTF-8"?> <xs:schema targetNamespace="http://www.example.com/test" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:t="http://www.example.com/test" > <xs:complexType name="BaseType"> <xs:all> <xs:element name="a" type="xs:string" /> </xs:all> </xs:complexType> <xs:complexType name="ExtendedType"> <xs:complexContent> <xs:extension base="t:BaseType"> <xs:all> <!-- ERROR --> <xs:element name="b" type="xs:string" /> </xs:all> </xs:extension> </xs:complexContent> </xs:complexType> <xs:element name="root" type="t:ExtendedType"></xs:element> </xs:schema> This xsd is not valid though, the following error is reported at <!-- ERROR -->: cos-all-limited.1.2: An all model group must appear in a particle with {min occurs} = {max occurs} = 1, and that particle must be part of a pair which constitutes the {content type} of a complex type definition. Documentation of cos-all-limited.1.2 says: 1.2 the {term} property of a particle with {max occurs}=1 which is part of a pair which constitutes the {content type} of a complex type definition. I don't really understand this (neither xsd nor English native speaker :) ). Am I doing the wrong thing, am I doing the right thing wrong, or is there no way to achieve this? Thanks!

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• How to define generic super type for static factory method?

  - by Esko

  If this has already been asked, please link and close this one. I'm currently prototyping a design for a simplified API of a certain another API that's a lot more complex (and potentially dangerous) to use. Considering the related somewhat complex object creation I decided to use static factory methods to simplify the API and I currently have the following which works as expected: public class Glue<T> { private List<Type<T>> types; private Glue() { types = new ArrayList<Type<T>>(); } private static class Type<T> { private T value; /* some other properties, omitted for simplicity */ public Type(T value) { this.value = value; } } public static <T> Glue<T> glueFactory(String name, T first, T second) { Glue<T> g = new Glue<T>(); Type<T> firstType = new Glue.Type<T>(first); Type<T> secondType = new Glue.Type<T>(second); g.types.add(firstType); g.types.add(secondType); /* omitted complex stuff */ return g; } } As said, this works as intended. When the API user (=another developer) types Glue<Horse> strongGlue = Glue.glueFactory("2HP", new Horse(), new Horse()); he gets exactly what he wanted. What I'm missing is that how do I enforce that Horse - or whatever is put into the factory method - always implements both Serializable and Comparable? Simply adding them to factory method's signature using <T extends Comparable<T> & Serializable> doesn't necessarily enforce this rule in all cases, only when this simplified API is used. That's why I'd like to add them to the class' definition and then modify the factory method accordingly. PS: No horses (and definitely no ponies!) were harmed in writing of this question.

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• generated service mock: everything but RhinoMocks fails?

  - by hko

  I have the "quest" to search for the next Mocking Framework for my company, and basically it's down to NSubstitute (simplest syntax, but no strict mocks), FakeItEasy(best reviews, Roy Osherove bonus, and slightly better lib support than NSubstitute), Moq (best "other libs support", biggest featureset, downside: mock.Object). We definitely want to move on from RhinoMocks, e.g. because of the unusefull interactiontest error messages (it should tell me what the parameter was instead, when a verification fails). So I was pretty surprised the other day (that was yesterday) when I found out RhinoMocks could do a thing where every other mock framework fails at: Mocking an autogenerated SomethingService (a typical VS autogenerated service with a default construtor in a partial class). Please don't argue about the design.. I intend to write lightweight integration tests (and some unit tests), and I can't mess around with the service, the product is installed on too many customers system. See this code: // here the NSubstitute and FakeItEasy equivalents throw an exception.. see below TicketStoreService fakeTicketStoreService = MockRepository.GenerateMock<TicketStoreService>(); fakeTicketStoreService.Expect(service => service.DoSomething(Arg.Is(new Guid())).Return(new Guid()); fakeTicketStoreService.DoSomething(Arg.Is(new Guid())); fakeTicketStoreService.VerifyAllExpectations(); Note that DoSomething is a non-virtual methodcall in an autogenerated class. So it shouldn't work, according to common knowledge. But it does. Problem is that it's the only (non commercial) framework that can do this: Rhino.Mocks works, and verification works too FakeItEasy says it doesn't find a default constructor (probably just wrong exception message): No default constructor was found on the type SomeNamespace.TicketStoreService Moq gives something sane and understandable: Invalid setup on a non-virtual (overridable in VB) member: service=> service.DoSomething Nsubstitute gives a message System.NotSupportedException: Cannot serialize member System.ComponentModel.Component.Site of type System.ComponentModel.ISite because it is an interface. I'm really wondering what's going on here with the frameworks, except Moq. The "fancy new" frameworks seem to have an initial perf hit too, probably preparing some Type cache and serializing stuff, whilst RhinoMocks somehow manages to create a very "slim" mock without recursion. I have to admit I didn't like RhinoMocks very well, but here it shines.. unfortunately. So, is there a way to get that to work with newer (non-commercial!) mocking frameworks, or somehow get a sane error message out of Rhino.Mocks? And why can Rhino.Mocks achieve this, when clearly every Mocking framework states it can only work with virtual methods when given a concrete class? Let's not derail the discussion by talking about alternative approaches like Extract&Override or runtime-proxy Mocking frameworks like JustMock/TypeMock/Moles or the new Fakes framework, I know these, but that would be less ideal solutions, for reasons beyond this topic. Any help appreciated..

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• How to generate and encode (for use in GA), random, strict, binary rooted trees with N leaves?

  - by Peter Simon

  First, I am an engineer, not a computer scientist, so I apologize in advance for any misuse of nomenclature and general ignorance of CS background. Here is the motivational background for my question: I am contemplating writing a genetic algorithm optimizer to aid in designing a power divider network (also called a beam forming network, or BFN for short). The BFN is intended to distribute power to each of N radiating elements in an array of antennas. The fraction of the total input power to be delivered to each radiating element has been specified. Topologically speaking, a BFN is a strictly binary, rooted tree. Each of the (N-1) interior nodes of the tree represents the input port of an unequal, binary power splitter. The N leaves of the tree are the power divider outputs. Given a particular power divider topology, one is still free to map the power divider outputs to the array inputs in an arbitrary order. There are N! such permutations of the outputs. There are several considerations in choosing the desired ordering: 1) The power ratio for each binary coupler should be within a specified range of values. 2) The ordering should be chosen to simplify the mechanical routing of the transmission lines connecting the power divider. The number of ouputs N of the BFN may range from, say, 6 to 22. I have already written a genetic algorithm optimizer that, given a particular BFN topology and desired array input power distribution, will search through the N! permutations of the BFN outputs to generate a design with compliant power ratios and good mechanical routing. I would now like to generalize my program to automatically generate and search through the space of possible BFN topologies. As I understand it, for N outputs (leaves of the binary tree), there are $C_{N-1}$ different topologies that can be constructed, where $C_N$ is the Catalan number. I would like to know how to encode an arbitrary tree having N leaves in a way that is consistent with a chromosomal description for use in a genetic algorithm. Also associated with this is the need to generate random instances for filling the initial population, and to implement crossover and mutations operators for this type of chromosome. Any suggestions will be welcome. Please minimize the amount of CS lingo in your reply, since I am not likely to be acquainted with it. Thanks in advance, Peter

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