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  • Problems with Json Serialize Dictionary<Enum, Int32>

    - by dbemerlin
    Hi, whenever i try to serialize the dictionary i get the exception: System.ArgumentException: Type 'System.Collections.Generic.Dictionary`2[[Foo.DictionarySerializationTest+TestEnum, Foo, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]' is not supported for serialization/deserialization of a dictionary, keys must be strings or object My Testcase is: public class DictionarySerializationTest { private enum TestEnum { A, B, C } public void SerializationTest() { Dictionary<TestEnum, Int32> data = new Dictionary<TestEnum, Int32>(); data.Add(TestEnum.A, 1); data.Add(TestEnum.B, 2); data.Add(TestEnum.C, 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Throws } public void SerializationStringTest() { Dictionary<String, Int32> data = new Dictionary<String, Int32>(); data.Add(TestEnum.A.ToString(), 1); data.Add(TestEnum.B.ToString(), 2); data.Add(TestEnum.C.ToString(), 3); JavaScriptSerializer serializer = new JavaScriptSerializer(); String result = serializer.Serialize(data); // Succeeds } } Of course i could use .ToString() whenever i enter something into the Dictionary but since it's used quite often in performance relevant methods i would prefer using the enum. My only solution is using .ToString() and converting before entering the performance critical regions but that is clumsy and i would have to change my code structure just to be able to serialize the data. Does anyone have an idea how i could serialize the dictionary as <Enum, Int32>? I use the System.Web.Script.Serialization.JavaScriptSerializer for serialization.

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  • Comparing dicts and update a list of result

    - by lmnt
    Hello, I have a list of dicts and I want to compare each dict in that list with a dict in a resulting list, add it to the result list if it's not there, and if it's there, update a counter associated with that dict. At first I wanted to use the solution described at http://stackoverflow.com/questions/1692388/python-list-of-dict-if-exists-increment-a-dict-value-if-not-append-a-new-dict but I got an error where one dict can not be used as a key to another dict. So the data structure I opted for is a list where each entry is a dict and an int: r = [[{'src': '', 'dst': '', 'cmd': ''}, 0]] The original dataset (that should be compared to the resulting dataset) is a list of dicts: d1 = {'src': '192.168.0.1', 'dst': '192.168.0.2', 'cmd': 'cmd1'} d2 = {'src': '192.168.0.1', 'dst': '192.168.0.2', 'cmd': 'cmd2'} d3 = {'src': '192.168.0.2', 'dst': '192.168.0.1', 'cmd': 'cmd1'} d4 = {'src': '192.168.0.1', 'dst': '192.168.0.2', 'cmd': 'cmd1'} o = [d1, d2, d3, d4] The result should be: r = [[{'src': '192.168.0.1', 'dst': '192.168.0.2', 'cmd': 'cmd1'}, 2], [{'src': '192.168.0.1', 'dst': '192.168.0.2', 'cmd': 'cmd2'}, 1], [{'src': '192.168.0.2', 'dst': '192.168.0.1', 'cmd': 'cmd1'}, 1]] What is the best way to accomplish this? I have a few code examples but none is really good and most is not working correctly. Thanks for any input on this! UPDATE The final code after Tamås comments is: from collections import namedtuple, defaultdict DataClass = namedtuple("DataClass", "src dst cmd") d1 = DataClass(src='192.168.0.1', dst='192.168.0.2', cmd='cmd1') d2 = DataClass(src='192.168.0.1', dst='192.168.0.2', cmd='cmd2') d3 = DataClass(src='192.168.0.2', dst='192.168.0.1', cmd='cmd1') d4 = DataClass(src='192.168.0.1', dst='192.168.0.2', cmd='cmd1') ds = d1, d2, d3, d4 r = defaultdict(int) for d in ds: r[d] += 1 print "list to compare" for d in ds: print d print "result after merge" for k, v in r.iteritems(): print("%s: %s" % (k, v))

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  • ListBox selector odd behavior when there are dupes

    - by byte1918
    I'm working on a bigger project atm, but I made this simple example to show you what happens.. using System.Collections.Generic; using System.Windows; namespace txt { public partial class MainWindow { public MainWindow() { InitializeComponent(); } private void Window_Loaded(object sender, RoutedEventArgs e) { var obsLst = new List<Info> { new Info { name = "asd" }, new Info { name = "asd" }, new Info { name = "asd" }, new Info { name = "asd" } }; var temp = new List<Info>(); for (var i = 1; i <= 3; i++) { temp.Add(obsLst[0]); //I add 3 of the same item from obsLst to temp } lst.DataContext = temp; //lst = ListBox } } public class Info { public string name { get; set; } } } The ListBox ItemsSource is set to {Binding}.. When I start the application I get 3 txt.Info objects displayed and if I click any of them, 2 or even all of them get selected aswell. From my understanding the problem relies in the fact that the listbox selector cannot differentiate between the items and therefor doesn't know which one I selected. Here's a picture of what it looks like.. I only clicked on the second txt.Info item. I found a solution where someone said that I have to specify the DisplayMemberPath, but I can't really do that in the other project because I have a datatemplate for the object. Any ideas on how I could fix this would be great.. Thx in advance.

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  • serial port does not exist in current context: c#

    - by I__
    here's the code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { private static SerialPort serialPort1; public static void DoWork() { serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); serialPort1.DataReceived += serialPort1_DataReceived_1; } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } and i get an error on this line: string response = serialPort1.ReadLine(); it says:: Error 1 The name 'serialPort1' does not exist in the current context C:\Users\alexluvsdanielle\AppData\Local\Temporary Projects\WindowsFormsApplication1\Form1.cs 44 31 WindowsFormsApplication1 what am i doing wrong?

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  • C++ destructos causing crash's

    - by larsonator
    ok, so i got a some what intricate program that simulates the uni systems of students, units, and students enrolling in units. Students are stored in a binary search tree, Units are stored in a standard list. Student has a list of Unit Pointers, to store which units he/she is enrolled in Unit has a list of Student pointers, to store students which are enrolled in that unit. The unit collections (storing units in a list) as made as a static variable where the main function is, as is the Binary search tree of students. when its finaly time to close the program, i call the destructors of each. but at some stage, during the destructors on the unit side, Unhandled exception at 0x002e4200 in ClassAllocation.exe: 0xC0000005: Access violation reading location 0x00000000. UnitCollection destructor: UnitCol::~UnitCol() { list<Unit>::iterator itr; for(itr = UnitCollection.begin(); itr != UnitCollection.end();) { UnitCollection.pop_front(); itr = UnitCollection.begin(); } } Unit Destructor Unit::~Unit() { } now i got the same sorta problem on the student side of things BST destructors void StudentCol::Destructor(const BTreeNode * r) { if(r!= 0) { Destructor(r->getLChild()); Destructor(r->getRChild()); delete r; } } StudentCol::~StudentCol() { Destructor(root); } Student Destructor Student::~Student() { } so yeah any help would be greatly appreciated

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  • Optimizing a bin-placement algorithm

    - by user258651
    Alright, I've got two collections, and I need to place elements from collection1 into the bins (elements) of collection2, based on whether their value falls within a given bin's range. For a concrete example, assume I have a sorted collection objects (bins) which have an int range ([1...4], [5..10], etc). I need to determine the range an int falls in, and place it in the appropriate bin. foreach(element n in collection1) { foreach(bin m in collection2) { if (m.inRange(n)) { m.add(n); break; } } } So the obvious NxM complexity algorithm is there, but I really would like to see Nxlog(M). To do this I'd like to use BinarySearch in place of the inner foreach loop. To use BinarySearch, I need to implement an IComparer class to do the searching for me. The problem I'm running into is this approach would require me to make an IComparer.Compare function that compares two different types of objects (an element to its bin), and that doesn't seem possible or correct. So I'm asking, how should I write this algorithm?

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  • Populate asp.net MVC Index page with data from the database

    - by Sunil Ramu
    I have a web application in which I need to fetch data from the database and display in the index page. As you know, asp.net mvc has given options to edit delete etc... I need to populate the page using the conventional DB way and it uses a stored procedure to retrieve results. I dont want to use LINQ. This is my model entity class using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace LogMVCApp.Models { public class Property { public int Id { get; set; } public string LogInId { get; set; } public string Username { get; set; } public string Action { get; set; } public string Information { get; set; } public bool Passed{get; set; } public string LogType { get; set; } } } and I need to retrieve data using something like this... var conString = ConfigurationManager.ConnectionStrings["connection"].ToString(); var conn = new SqlConnection(conString); var command = new SqlCommand("LogInsert", conn){CommandType=CommandType.StoredProcedure};

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  • Writing to the DataContext

    - by user738383
    I have a function. This function takes an IEnumerable<Customer> (Customer being an entity). What the function needs to do is tell the DataContext (which has a collection of Customers as a property) that its Customers property needs to be overwritten with this passed in IEnumerable<Customer>. I can't use assignment because DomainContext.Customers cannot be assigned to, as it is read only. I guess it's not clear what I'm asking, so I suppose I should say... how do I do that? So we have DataContext.Customers (of type System.Data.Linq.Table) which wants to be replaced with a System.Collections.Generic.IEnumerable. I can't just assign the latter to the former because DataContext's properties are read only. But there must be a way. Edit: here's an image: Further edit: Yes, this image does not feature a collection of the type 'Customer' but rather 'Connection'. It doesn't matter though, they are both created from tables within the linked SQL database. So there is a dc.Connections, a dc.Customers, a dc.Media and so on. Thanks in advance.

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  • Wrong answer on c# application, finding the n prime of a list of prime numbers.

    - by user300484
    Hello, I am new to C# and I am practicing by trying to solve this easy C# problem. This application will receive an "n" number. After receiving this number, the program has to show the n prime of the list of primes. For example, if the user enters "3", the program is supposed to display "5", because 5 is the third prime starting at 2. I koow that something is wrong with my code but I dont know where is the problem and how I can fix it. Can you please tell me? Thank you :P using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Console.WriteLine("Determinar el n-esimo primo."); long n = Convert.ToInt64(Console.ReadLine()); // N lugar de primos long[] array = new long[n]; long c=0; while (c >= 2) { if(siprimo(c++) == true) for (long i = 0; i < n; i++) { array[i] = c; } } Console.WriteLine(array[n - 1]); Console.ReadLine(); } static private bool siprimo(long x) { bool sp = true; for (long k = 2; k <= x / 2; k++) if (x % k == 0) sp = false; return sp; } } }

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  • RTTI Dynamic array TValue Delphi 2010

    - by user558126
    Hello I have a question. I am a newbie with Run Time Type Information from Delphi 2010. I need to set length to a dynamic array into a TValue. You can see the code. Type TMyArray = array of integer; TMyClass = class publihed function Do:TMyArray; end; function TMyClass.Do:TMyArray; begin SetLength(Result,5); for i:=0 to 4 Result[i]=3; end; ....... ....... ...... y:TValue; Param:array of TValue; ......... y=Methods[i].Invoke(Obj,Param);//delphi give me a DynArray type kind, is working, Param works to any functions. if Method[i].ReturnType.TypeKind = tkDynArray then//is working... begin I want to set length for y to 10000//i don't know how to write. end; I don't like Generics Collections.

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  • How to parse XML to flex Data Grid contents.

    - by Jeeva
    My xml file which is in a webserver is show below. <root> <userdetails> <username>raja</username> <status>offline</status> </userdetails> <userdetails> <username>Test</username> <status>online</status> </userdetails> </root> How can i parse this to flex data grid contents. I tried with below coding < ?xml version="1.0" encoding="utf-8"? < mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="initApp()" < mx:HTTPService id="userList" result="handleData(event)" resultFormat="object" url="http://apps.facebook.com/ajparkin/user_list.xml" / <mx:Script> <![CDATA[ import mx.collections.ArrayCollection; import mx.rpc.events.ResultEvent; import mx.controls.Alert; public function initApp():void { userList.send(); } [Bindable] var userdetailsArray:ArrayCollection; private function handleData(evt:ResultEvent):void { this.userdetailsArray= evt.result.userdetails; } ]]> </mx:Script> <mx:DataGrid dataProvider="{userdetailsArray}"> <mx:columns> <mx:DataGridColumn dataField="username" headerText="User Name"/> <mx:DataGridColumn dataField="status" headerText="Status" /> </mx:columns> </mx:DataGrid> </mx:Application> I'm getting only the field names not the data.

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  • How to enumerate word document using office interop API?

    - by Shekhar
    Hello everyone, I want to traverse through all the elements of an word document one by one and according to type of element (header, sentence, table,image,textbox, shape, etc.) I want to process that element. I tried to search any enumerator or object which can represent elements of document in office interop API but failed to find any. API offers sentences, paragraphs, shapes collections but doesnt provide generic object which can point to next element. For example : <header of document> <plain text sentences> <table with many rows,columns> <text box> <image> <footer> (Please imagine it as a word document) So, now I want some enumerator which will first give me <header of document>, then on next iteration give me <plain text sentences>, then <table with many rows,columns> and so on. Does anyone knows how we can achieve this? Is it possible? I am using C#, visual studio 2005 and Word 2003. Thanks a lot

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  • How to close all tabs in Safari using AppleScript?

    - by Form
    I have made a very simple AppleScript to close all tabs in Safari. The problem is, it works, but not completely. Here's the code: tell application "Safari" repeat with aWindow in windows repeat with aTab in tabs of aWindow aTab close end repeat end repeat end tell I've also tried this script: tell application "Safari" repeat with i from 0 to the number of items in windows set aWindow to item i of windows repeat with j from 0 to the number of tabs in aWindow set aTab to item j of tabs of aWindow aTab close end repeat end repeat end tell ... but it does not work either. I tried that on my system (MacBook Pro jan 2008), as well as on a Mac Pro G5 under Tiger and the script fails on both, albeit with a much less descriptive error on Tiger. The problem is that only a couple of tabs are closed. Running the script a few times closes a few tab each time until none is left, but always fails with the same error after closing a few tabs. Under Leopard I get an out of bounds error. Since I am using fast enumeration (not using "repeat from 0 to number of items in windows") I don't see how I can get an out of bounds error with this... My goal is to use the Cocoa Scripting Bridge to close tabs in Safari from my Objective-C Cocoa application but the Scripting Bridge fails in the same manner. The non-deletable tabs show as NULL in the Xcode debugger, while the other tabs are valid objects from which I can get values back (such as their title). In fact I tried with the Scripting Bridge first then told myself why not try this directly in AppleScript and I was surprised to see the same results. I must have a glaring omission or something in there... (seems like a bug in Safari AppleScript support to me... :S) I've used repeat loops and Obj-C 2.0 fast enumeration to iterate through collections before with zero problems, so I really don't see what's wrong here. Anyone can help? Thanks in advance!

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  • <string xmlns=''> was not expected in c#

    - by Nishant
    Hi all I am trying to serialize value in xml. Every time I am getting <string xmlns=''> was not expected in c# Not able to find root cause plz help me out here. namespace CustomDataType.usercontrols { public partial class CustomDataTypes : System.Web.UI.UserControl, umbraco.editorControls.userControlGrapper.IUsercontrolDataEditor { private Status _umbval; public object value { get { var status = GetStatus(); return SerializationHelper.ValueToXmlString(status); } set { //if (value == null || string.IsNullOrEmpty(value.ToString())) //{ // _umbval = Status.Empty; //} //else //{ _umbval =(Status)SerializationHelper.ValueFromXmlString(value,typeof(Status)); //} } } } } using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Xml.Serialization; namespace CustomDataType { [Serializable] [XmlRoot("StatuMain")] public class Status { [XmlElement("statusvalue")] public string StatusValue { get; set; } [XmlElement("statusvalue1")] public string StatusValue1 { get; set; } [XmlElement("statusvalue2")] public string StatusValue2 { get; set; } [XmlElement("statusvalue3")] public string StatusValue3 { get; set; } //[XmlElement("isEmailChecked")] //public bool HasEmailChecked { get; set; } //[XmlElement("datetime")] //public DateTime Date { get; set; } public static Status Empty { get { var schedule = new Status(); schedule = null; return schedule; } } } }

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  • how can i handle calculator buutons in c# window form program

    - by sama
    using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; namespace lab8ass1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button11_Click(object sender, EventArgs e) { textBox1.Text += "."; } private void btnone_Click(object sender, EventArgs e) { textBox1.Text += "1"; } private void btnrwo_Click(object sender, EventArgs e) { textBox1.Text += "2"; } private void btnthree_Click(object sender, EventArgs e) { textBox1.Text += "3"; } private void btnfour_Click(object sender, EventArgs e) { textBox1.Text += "4"; } private void btnfive_Click(object sender, EventArgs e) { textBox1.Text += "5"; } private void btnsix_Click(object sender, EventArgs e) { textBox1.Text += "6"; } private void btnseven_Click(object sender, EventArgs e) { textBox1.Text += "7"; } private void btneight_Click(object sender, EventArgs e) { textBox1.Text += "8"; } private void btnnine_Click(object sender, EventArgs e) { textBox1.Text += "9"; } private void btnzero_Click(object sender, EventArgs e) { textBox1.Text += "0"; } string s1,s; private void btnplus_Click(object sender, EventArgs e) { s1 = textBox1.Text; textBox1.Text = ""; s = textBox1.Text; //textBox1.Text } private void btnequal_Click(object sender, EventArgs e) { } } } here my code how can i handle calculator buutons

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  • C++ destructors causing crash's

    - by larsonator
    ok, so i got a some what intricate program that simulates the uni systems of students, units, and students enrolling in units. Students are stored in a binary search tree, Units are stored in a standard list. Student has a list of Unit Pointers, to store which units he/she is enrolled in Unit has a list of Student pointers, to store students which are enrolled in that unit. The unit collections (storing units in a list) as made as a static variable where the main function is, as is the Binary search tree of students. when its finaly time to close the program, i call the destructors of each. but at some stage, during the destructors on the unit side, Unhandled exception at 0x002e4200 in ClassAllocation.exe: 0xC0000005: Access violation reading location 0x00000000. UnitCollection destructor: UnitCol::~UnitCol() { list<Unit>::iterator itr; for(itr = UnitCollection.begin(); itr != UnitCollection.end();) { UnitCollection.pop_front(); itr = UnitCollection.begin(); } } Unit Destructor Unit::~Unit() { } now i got the same sorta problem on the student side of things BST destructors void StudentCol::Destructor(const BTreeNode * r) { if(r!= 0) { Destructor(r->getLChild()); Destructor(r->getRChild()); delete r; } } StudentCol::~StudentCol() { Destructor(root); } Student Destructor Student::~Student() { } so yeah any help would be greatly appreciated

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  • file upload in JSF using myfaces component

    - by prt
    Hi, all i am creating a JSF application where file uploading functionality is required.I have added all the required jar files in my /WEB-INF/lib folder. jsf-api.jar jsf-impl.jar jstl.jar standard.jar myfaces-extensions.jar commons-collections.jar commons-digester.jar commons-beanutils.jar commons-logging.jar commons-fileupload-1.0.jar but still when trying to deploy the application on apache 6.0.29 i am getting the following error. org.apache.catalina.core.StandardContext addApplicationListener INFO: The listener "com.sun.faces.config.ConfigureListener" is already configured for this context. The duplicate definition has been ignored. org.apache.catalina.core.StandardContext start SEVERE: Error listenerStart PM org.apache.catalina.core.StandardContext start SEVERE: Context [/jsfApplication] startup failed due to previous errors org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc The web application [/jsfApplication] registered the JBDC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered. org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/jsfApplication] appears to have started a thread named [Timer-0] but has failed to stop it. This is very likely to create a memory leak. org.apache.catalina.loader.WebappClassLoader clearReferencesThreads SEVERE: The web application [/jsfApplication] appears to have started a thread named [MySQL Statement Cancellation Timer] but has failed to stop it. This is very likely to create a memory leak. log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository. i am using also using hibernate and spring framework for this application. please help. thanks,

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  • Visitor Pattern can be replaced with Callback functions?

    - by getit
    Is there any significant benefit to using either technique? In case there are variations, the Visitor Pattern I mean is this: http://en.wikipedia.org/wiki/Visitor_pattern And below is an example of using a delegate to achieve the same effect (at least I think it is the same) Say there is a collection of nested elements: Schools contain Departments which contain Students Instead of using the Visitor pattern to perform something on each collection item, why not use a simple callback (Action delegate in C#) Say something like this class Department { List Students; } class School { List Departments; VisitStudents(Action<Student> actionDelegate) { foreach(var dep in this.Departments) { foreach(var stu in dep.Students) { actionDelegate(stu); } } } } School A = new School(); ...//populate collections A.Visit((student)=> { ...Do Something with student... }); *EDIT Example with delegate accepting multiple params Say I wanted to pass both the student and department, I could modify the Action definition like so: Action class School { List Departments; VisitStudents(Action<Student, Department> actionDelegate, Action<Department> d2) { foreach(var dep in this.Departments) { d2(dep); //This performs a different process. //Using Visitor pattern would avoid having to keep adding new delegates. //This looks like the main benefit so far foreach(var stu in dep.Students) { actionDelegate(stu, dep); } } } }

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  • When are predicates appropriate and what is the best pattern for usage

    - by Maxim Gershkovich
    When are predicates appropriate and what is the best pattern for usage? What are the advantages of predicates? It seems to me like most cases where a predicate can be employed a tight loop would accomplish the same functionality? I don’t see a reusability argument given you will probably only implement a predicate in one method right? They look and feel nice but besides that they seem like you would only employ them when you need a quick hack on the collection classes? UPDATE But why would you be rewriting the tight loop again and again? In my mind/code when it comes to collections I always end up with something like Class Person End Class Class PersonList Inherits List(Of Person) Function FindByName(Name) as Person tight loop.... End Function End Class @Ani By that same logic I could implement the method as such Class PersonList Inherits List(Of Person) Function FindByName(Name) as PersonList End Function Function FindByAge(Age) as PersonList End Function Function FindBySocialSecurityNumber(SocialSecurityNumber) as PersonList End Function End Class And call it as such Dim res as PersonList = MyList.FindByName("Max").FindByAge(25).FindBySocialSecurityNumber(1234) and the result along with the amount of code and its reusability is largely the same, no? I am not arguing just trying to understand.

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  • Object Design: How to Organize/Structure a "Collection Class"

    - by CrimsonX
    I'm currently struggling to understand how I should organize/structure a class which I have already created. The class does the following: As its input in the constructor, it takes a collection of logs In the constructor it validates and filters the logs through a series of algorithms implementing my business logic After all filtering and validation is complete, it returns a collection (a List) of the valid and filtered logs which can be presented to the user graphically in a UI. Here is some simplified code describing what I'm doing: class FilteredCollection { public FilteredCollection( SpecialArray<MyLog> myLog) { // validate inputs // filter and validate logs in collection // in end, FilteredLogs is ready for access } Public List<MyLog> FilteredLogs{ get; private set;} } However, in order to access this collection, I have to do the following: var filteredCollection = new FilteredCollection( secialArrayInput ); //Example of accessing data filteredCollection.FilteredLogs[5].MyLogData; Other key pieces of input: I foresee only one of these filtered collections existing in the application (therefore should I make it a static class? Or perhaps a singleton?) Testability and flexibility in creation of the object is important (Perhaps therefore I should keep this an instanced class for testability?) I'd prefer to simplify the dereferencing of the logs if at all possible, as the actual variable names are quite long and it takes some 60-80 characters to just get to the actual data. My attempt in keeping this class simple is that the only purpose of the class is to create this collection of validated data. I know that there may be no "perfect" solution here, but I'm really trying to improve my skills with this design and I would greatly appreciate advice to do that. Thanks in advance.

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  • Threadsafe way of exposing keySet()

    - by Jake
    This must be a fairly common occurrence where I have a map and wish to thread-safely expose its key set: public MyClass { Map<String,String> map = // ... public final Set<String> keys() { // returns key set } } Now, if my "map" is not thread-safe, this is not safe: public final Set<String> keys() { return map.keySet(); } And neither is: public final Set<String> keys() { return Collections.unmodifiableSet(map.keySet()); } So I need to create a copy, such as: public final Set<String> keys() { return new HashSet(map.keySet()); } However, this doesn't seem safe either because that constructor traverses the elements of the parameter and add()s them. So while this copying is going on, a ConcurrentModificationException can happen. So then: public final Set<String> keys() { synchronized(map) { return new HashSet(map.keySet()); } } seems like the solution. Does this look right?

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  • Dependency Injection into your Singleton

    - by Langali
    I have a singleton that has a spring injected Dao (simplified below): public class MyService<T> implements Service<T> { private final Map<String, T> objects; private static MyService instance; MyDao myDao; public void set MyDao(MyDao myDao) { this. myDao = myDao; } private MyService() { this.objects = Collections.synchronizedMap(new HashMap<String, T>()); // start a background thread that runs for ever } public static synchronized MyService getInstance() { if(instance == null) { instance = new MyService(); } return instance; } public void doSomething() { myDao.persist(objects); } } My spring config will probably look like this: <bean id="service" class="MyService" factory-method="getInstance"/> But this will instantiate the MyService during startup. Is there a programmatic way to do a dependency injection of MyDao into MyService, but not have spring manage the MyService? Basically I want to be able to do this from my code: MyService.getInstance().doSomething(); while having spring inject the MyDao for me.

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  • Passing information safely between Wicket and Hibernate in long running conversations

    - by Peter Tillemans
    We are using Wicket with Hibernate in the background. As part of out UI we have quite long running conversations spanning multiple requests before the updated information is written back to the database. To avoid getting hibernate errors with detached objects we are now using value objects to transfer info from the service layer to Wicket. However we now end up with an explosion of almost the same objects : e.g. Answer (mapped entity saved in hibernate) AnswerVO (immutable value object) AnswerModel (A mutable bean in the session domain) IModel wrapped Wicket Model and usually this gets wrapped in a CompoundPropertyModel This plumbing becomes exponentially worse when collections to other objects are involved in the objects. There has to be a better way to organize this. Can anyone share tips to make this less onerous? Maybe make the value objects mutable so we can remove the need for a seaprate backing bean in Wicket? Use the entity beans but absolutely make dead-certain they are detached from hibernate. (easier said than done)? Some other tricks or patterns?

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  • Limit TCP requests per IP

    - by asmo
    Hello! I'm wondering how to limit the TCP requests per client (per specific IP) in Java. For example, I would like to allow a maximum of X requests per Y seconds for each client IP. I thought of using static Timer/TimerTask in combination with a HashSet of temporary restricted IPs. private static final Set<InetAddress> restrictedIPs = Collections.synchronizedSet(new HashSet<InetAddress>()); private static final Timer restrictTimer = new Timer(); So when a user connects to the server, I add his IP to the restricted list, and start a task to unrestrict him in X seconds. restrictedIPs.add(socket.getInetAddress()); restrictTimer.schedule(new TimerTask() { public void run() { restrictedIPs.remove(socket.getInetAddress()); } }, MIN_REQUEST_INTERVAL); My problem is that at the time the task will run, the socket object may be closed, and the remote IP address won't be accessible anymore... Any ideas welcomed! Also, if someone knows a Java-framework-built-in way to achieve this, I'd really like to hear it.

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  • how to place dropdown list box in jquery grid column

    - by kumar
    Hello friends, I have a jquery grid columns defined like this.. using System; using System.Collections.Generic; using System.Linq; using System.Web; using Trirand.Web.Mvc; using System.Web.UI.WebControls; namespace JQGridMVCExamples.Models { public class OrdersJqGridModel { public OrdersJqGridModel() { OrdersGrid = new JQGrid { Columns = new List<JQGridColumn>() { new JQGridColumn { DataField = "OrderID", Width = 50 }, new JQGridColumn { DataField = "OrderDate", Width = 100, DataFormatString = "{0:d}" }, new JQGridColumn { DataField = "CustomerID", Width = 100 }, new JQGridColumn { DataField = "Freight", Width = 75 }, new JQGridColumn { DataField = "ShipName" } }, Width = Unit.Pixel(640) }; OrdersGrid.ToolBarSettings.ShowRefreshButton = true; } public JQGrid OrdersGrid { get; set; } } } and in the view I am caling like this <div> <%= Html.Trirand().JQGrid(Model.OrdersGrid, "JQGrid1") %> </div> I am getting result perfect.. but for column Freight in the Jquery grid I need to place a dropdown list dynamically for all result rows.. can anyone help me out.. THanks

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