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  • What is the best method to convert to an Integer in JavaScript?

    - by Mathew Byrne
    There are several different methods for converting floating point numbers to Integers in JavaScript. My question is what method gives the best performance, is most compatible, or is considered the best practice? Here are a few methods that I know of: var a = 2.5; window.parseInt(a); // 2 Math.floor(a); // 2 a | 0; // 2 I'm sure there are others out there. Suggestions?

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  • Managed .NET Equivalent to CreateFile & WriteFile from WinBase (kernel32.dll)

    - by StevenH
    I am working with a legacy file format. The file is created using unmanaged C++ that utilizes the WinBase.h CreateFile() & WriteFile() functions (found in the kernel32.dll). I have been using P/Invoke interop to access these native functions like so: [DllImport("kernel32.dll")] public static extern bool WriteFile( IntPtr hFile, byte[] lpBuffer, uint nNumberOfBytesToWrite, out uint lpNumberOfBytesWritten, [In] ref NativeOverlapped lpOverlapped); [DllImport("kernel32.dll", SetLastError = true)] public static extern bool WriteFileEx( IntPtr hFile, byte[] lpBuffer, uint nNumberOfBytesToWrite, [In] ref NativeOverlapped lpOverlapped, WriteFileCompletionDelegate lpCompletionRoutine); [DllImport("kernel32.dll", SetLastError = true)] public static extern IntPtr CreateFile( string lpFileName, uint dwDesiredAccess, uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition, uint dwFlagsAndAttributes, IntPtr hTemplateFile); [DllImport("kernel32.dll", SetLastError = true)] public static extern bool CloseHandle(IntPtr hObject); public delegate void WriteFileCompletionDelegate( UInt32 dwErrorCode, UInt32 dwNumberOfBytesTransfered, ref NativeOverlapped lpOverlapped); The issue with this is when I call WriteFile(), the file is always overwritten by the proceeding call. I need to find a compatible .NET equivalent that would allow me to produce the exact same format of output. Thanks.

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  • How are property assignment expressions handled in C#?

    - by Serious
    In C# you can use a property as both an lrvalue and rvalue at the same time like this : int n = N = 1; Here is a complete C# sample : class Test { static int n; static int N { get { System.Console.WriteLine("get"); return n; } set { System.Console.WriteLine("set"); n = value; } } static void Main() { int n = N = 1; System.Console.WriteLine("{0}/{1}", n, N); } } You can't do that in C++/CLI as the resulting type of the assignment expression "N = 1" is void. EDIT: here is a C++/CLI sample that shows this : ref class A { public: static property int N; }; int main() { int n = A::N = 1; System::Console::WriteLine("{0}/{1}", n, A::N); } So what's the magic behind C# syntax allowing a void-expression to be used as a rvalue ? Is this special treatment only available for properties or do you know other C# tricks like this ?

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  • problems with retrieving data that was saved outside of a grails webflow

    - by callie16
    Hi, this is actually connected to an earlier question of mine here. Anyway, I have 3 domains that look like this: class A { ... static hasMany = [ b : B ] ... } class B { ... static belongsTo = [ a : A ] static hasMany = [ c : C ] ... } class C { ... static belongsTo = [ b : B ] ... } In my GSP page, I call an action in the Controller via a remote function in a javascript block (I'm using Dojo so I'm passing data to be saved this way... it's not a form per se so I use JSON for now to pass the data to the Controller). Let's say, I'm calling something like this: def someAction = { def jsonArr = [parse the JSON here] def tmpA = A.get(params.id) ... def tmpB = new B() b.someParam = jsonArr.someParam ... def tmpC = new C() tmpC.cParam = jsonArr.cParam tmpB.addToC(tmpC) tmpB.save(flush: true) //this may or may not be here but I'm adding it for the sake of completeness tmpA.addToB(tmpB) tmpA.save(flush: true) // NOTE: If I check here via println or whatnot, tmpA has a tmpB which has a tmpC... in other words, the data got saved. It's also in the DB. redirect(action: 'order' ...) } Then comes the fun part. Here's the webflow sample: def orderFlow = { ... someStateIShouldEndUpIn { on("next") { // or on previous... doesn't matter def anId = params.id def currA = A.get(anId) // this does NOT return a null value def testB = currA.b // this DOES return a null value }.to("somePage") ... } ... } Any ideas on why this happens? Moreover, when I dump the data of currA, b=null... instead of b=[] or b=[contents of tmpB]. Any help would be seriously appreciated... been at this for a couple of days now... Thanks!

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  • Seeking suggestions on redesigning the interface

    - by ratkok
    As a part of maintaining large piece of legacy code, we need to change part of the design mainly to make it more testable (unit testing). One of the issues we need to resolve is the existing interface between components. The interface between two components is a class that contains static methods only. Simplified example: class ABInterface { static methodA(); static methodB(); ... static methodZ(); }; The interface is used by component A so that different methods can use ABInterface::methodA() in order to prepare some input data and then invoke appropriate functions within component B. Now we are trying to redesign this interface for various reasons: Extending our unit test coverage - we need to resolve this dependency between the components and stubs/mocks are to be introduced The interface between these components diverged from the original design (ie. a lots of newer functions, used for the inter-component i/f are created outside this interface class). The code is old, changed a lot over the time and needs to be refactored. The change should not be disruptive for the rest of the system. We try to limit leaving many test-required artifacts in the production code. Performance is very important and should be no (or very minimal) degradation after the redesign. Code is OO in C++. I am looking for some ideas what approach to take. Any suggestions on how to do this efficiently?

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  • C++ data member initializer is not allowed

    - by user1435915
    I totally new to C++ so bear with me. I want to make a class with a static array, and access to this array from the main. Here is what i want to do in C#. namespace ConsoleApplication1 { class Program { static void Main(string[] args) { Class a = new Class(); Console.WriteLine(a.arr[1]); } } } ===================== namespace ConsoleApplication1 { class Class { public static string[] s_strHands = new string[]{"one","two","three"}; } } Here is what i have tried: // justfoolin.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <string> #include <iostream> using namespace std; class Class { public: static string arr[3] = {"one", "two", "three"}; }; int _tmain(int argc, _TCHAR* argv[]) { Class x; cout << x.arr[2] << endl; return 0; } But i got: IntelliSense: data member initializer is not allowed

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  • Type classe, generic memoization

    - by nicolas
    Something quite odd is happening with y types and I quite dont understand if this is justified or not. I would tend to think not. This code works fine : type DictionarySingleton private () = static let mutable instance = Dictionary<string*obj, obj>() static member Instance = instance let memoize (f:'a -> 'b) = fun (x:'a) -> let key = f.ToString(), (x :> obj) if (DictionarySingleton.Instance).ContainsKey(key) then let r = (DictionarySingleton.Instance).[key] r :?> 'b else let res = f x (DictionarySingleton.Instance).[key] <- (res :> obj) res And this ones complains type DictionarySingleton private () = static let mutable instance = Dictionary<string*obj, _>() static member Instance = instance let memoize (f:'a -> 'b) = fun (x:'a) -> let key = f.ToString(), (x :> obj) if (DictionarySingleton.Instance).ContainsKey(key) then let r = (DictionarySingleton.Instance).[key] r :?> 'b else let res = f x (DictionarySingleton.Instance).[key] <- (res :> obj) res The difference is only the underscore in the dictionary definition. The infered types are the same, but the dynamic cast from r to type 'b exhibits an error. 'this runtime coercition ... runtime type tests are not allowed on some types, etc..' Am I missing something or is it a rough edge ?

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  • How can change my code to can user insert numbers of year and days ?

    - by MANAL
    I make code to calculate the date of today and the date for two years ago before the day of today and also calculate day before 5 days. I want user insert the numbers of years and days to make compare between date of today . import java.util.Date; import java.util.Calendar; import java.text.SimpleDateFormat; import java.util.Scanner; public class Calendar1 { private static void doCalendarTime() { System.out.print("*************************************************"); Date now = Calendar.getInstance().getTime(); System.out.print(" \n Calendar.getInstance().getTime() : " + now); System.out.println(); } private static void doSimpleDateFormat() { System.out.print("*************************************************"); System.out.print("\n\nSIMPLE DATE FORMAT\n"); System.out.print("*************************************************"); // Get today's date Calendar now = Calendar.getInstance(); SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz"); System.out.print(" \n It is now : " + formatter.format(now.getTime())); System.out.println(); } private static void doAdd() { System.out.println("ADD / SUBTRACT CALENDAR / DATEs"); System.out.println("================================================================="); // Get today's date Calendar now = Calendar.getInstance(); Calendar working; SimpleDateFormat formatter = new SimpleDateFormat("E yyyy.MM.dd 'at' hh:mm:ss a zzz"); working = (Calendar) now.clone(); working.add(Calendar.DAY_OF_YEAR, - (365 * 2)); System.out.println (" Two years ago it was: " + formatter.format(working.getTime())); working = (Calendar) now.clone(); working.add(Calendar.DAY_OF_YEAR, + 5); System.out.println(" In five days it will be: " + formatter.format(working.getTime())); System.out.println(); } public static void main(String[] args) { System.out.println(); doCalendarTime(); doSimpleDateFormat(); doAdd(); } } help me .

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  • Why is Func<T> ambiguous with Func<IEnumerable<T>>?

    - by Matt Hamilton
    This one's got me flummoxed, so I thought I'd ask here in the hope that a C# guru can explain it to me. Why does this code generate an error? class Program { static void Main(string[] args) { Foo(X); // the error is on this line } static String X() { return "Test"; } static void Foo(Func<IEnumerable<String>> x) { } static void Foo(Func<String> x) { } } The error in question: Error 1 The call is ambiguous between the following methods or properties: 'ConsoleApplication1.Program.Foo(System.Func<System.Collections.Generic.IEnumerable<string>>)' and 'ConsoleApplication1.Program.Foo(System.Func<string>)' C:\Users\mabster\AppData\Local\Temporary Projects\ConsoleApplication1\Program.cs 12 13 ConsoleApplication1 It doesn't matter what type I use - if you replace the "String" declarations with "int" in that code you'll get the same sort of error. It's like the compiler can't tell the difference between Func<T> and Func<IEnumerable<T>>. Can someone shed some light on this?

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  • how to share a variable between two threads

    - by prmatta
    I just inherited some code, two threads within this code need to perform a system task. One thread should do the system task before the other thread. They should not be performing the system task together. The two threads do not have references to each other. Now, I know I can use some sort of a semaphore to achieve this. But my question is what is the right way to get both threads to access this semaphore. I could create a static variable/method a new class : public class SharedSemaphore { private static Semaphore s = new Semaphore (1, true); public static void performSystemTask () { s.acquire(); } public static void donePerformingSystemTask() { s.release(); } } This would work (right?) but this doesn't seem like the right thing to do. Because, the threads now have access to a semaphore, without ever having a reference to it. This sort of thing doesn't seem like a good programming practice. Am I wrong?

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  • What to Expect in Rails 4

    - by mikhailov
    Rails 4 is nearly there, we should be ready before it released. Most developers are trying hard to keep their application on the edge. Must see resources: 1) @sikachu talk: What to Expect in Rails 4.0 - YouTube 2) Rails Guides release notes: http://edgeguides.rubyonrails.org/4_0_release_notes.html There is a mix of all major changes down here: ActionMailer changes excerpt: Asynchronously send messages via the Rails Raise an ActionView::MissingTemplate exception when no implicit template could be found ActionPack changes excerpt Added controller-level etag additions that will be part of the action etag computation Add automatic template digests to all CacheHelper#cache calls (originally spiked in the cache_digests plugin) Add Routing Concerns to declare common routes that can be reused inside others resources and routes Added ActionController::Live. Mix it in to your controller and you can stream data to the client live truncate now always returns an escaped HTML-safe string. The option :escape can be used as false to not escape the result Added ActionDispatch::SSL middleware that when included force all the requests to be under HTTPS protocol ActiveModel changes excerpt AM::Validation#validates ability to pass custom exception to :strict option Changed `AM::Serializers::JSON.include_root_in_json' default value to false. Now, AM Serializers and AR objects have the same default behaviour Added ActiveModel::Model, a mixin to make Ruby objects work with AP out of box Trim down Active Model API by removing valid? and errors.full_messages ActiveRecord changes excerpt Use native mysqldump command instead of structure_dump method when dumping the database structure to a sql file. Attribute predicate methods, such as article.title?, will now raise ActiveModel::MissingAttributeError if the attribute being queried for truthiness was not read from the database, instead of just returning false ActiveRecord::SessionStore has been extracted from Active Record as activerecord-session_store gem. Please read the README.md file on the gem for the usage Fix reset_counters when there are multiple belongs_to association with the same foreign key and one of them have a counter cache Raise ArgumentError if list of attributes to change is empty in update_all Add Relation#load. This method explicitly loads the records and then returns self Deprecated most of the 'dynamic finder' methods. All dynamic methods except for find_by_... and find_by_...! are deprecated Added ability to ActiveRecord::Relation#from to accept other ActiveRecord::Relation objects Remove IdentityMap ActiveSupport changes excerpt ERB::Util.html_escape now escapes single quotes ActiveSupport::Callbacks: deprecate monkey patch of object callbacks Replace deprecated memcache-client gem with dalli in ActiveSupport::Cache::MemCacheStore Object#try will now return nil instead of raise a NoMethodError if the receiving object does not implement the method, but you can still get the old behavior by using the new Object#try! Object#try can't call private methods Add ActiveSupport::Deprecations.behavior = :silence to completely ignore Rails runtime deprecations What are the most important changes for you?

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  • Dependency Properties, change notification and setting values in the constructor

    - by stefan.at.wpf
    Hello, I have a clas with 3 dependency properties A,B,C. The values of these properties are set by the constructor and every time one of the properties A, B or C changes, the method recalculate() is called. Now during execution of the constructor these method is called 3 times, because the 3 properties A, B, C are changed. Hoewever this isn't necessary as the method recalculate() can't do anything really useful without all 3 properties set. So what's the best way for property change notification but circumventing this change notification in the constructor? I thought about adding the property changed notification in the constructor, but then each object of the DPChangeSample class would always add more and more change notifications. Thanks for any hint! class DPChangeSample : DependencyObject { public static DependencyProperty AProperty = DependencyProperty.Register("A", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); public static DependencyProperty BProperty = DependencyProperty.Register("B", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); public static DependencyProperty CProperty = DependencyProperty.Register("C", typeof(int), typeof(DPChangeSample), new PropertyMetadata(propertyChanged)); private static void propertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { ((DPChangeSample)d).recalculate(); } private void recalculate() { // Using A, B, C do some cpu intensive caluclations } public DPChangeSample(int a, int b, int c) { SetValue(AProperty, a); SetValue(BProperty, b); SetValue(CProperty, c); } }

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  • UnsupportedOperationException on Collection

    - by Duke Vador
    While studying the Collection API, we find that some methods (add, remove,...) may throw a java.lang.UnsupportedOperationException if the current implementation of the Collection does not support those functionalities. Is there,actually, in the JDK, a concrete Collection that does not support those methods ? Thanks a lot for your answers.

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  • Symfony 1.4 : can't use flash method in prod environment

    - by Gaff
    Hello, I'm using the setFlash and hasFlash methods of symfony 1.4 with WAMP 2.0 Locally with my frontend_dev app, all work fine. But in production environment, my test $this->forward404Unless($user->hasFlash('resultsArray')); fails. I thought that the flash methods where enabled by default. What can I do to make it works please ? Thanks in advance, Gaff.

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  • Nullable<T> as a parameter

    - by ferch
    I alredy have this: public static object GetDBValue(object ObjectEvaluated) { if (ObjectEvaluated == null) return DBNull.Value; else return ObjectEvaluated; } used like: List<SqlParameter> Params = new List<SqlParameter>(); Params.Add(new SqlParameter("@EntityType", GetDBValue(EntityType))); Now i wanted to keep the same interface but extend that to use it with nullable public static object GetDBValue(int? ObjectEvaluated) { if (ObjectEvaluated.HasValue) return ObjectEvaluated.Value; else return DBNull.Value; } public static object GetDBValue(DateTime? ObjectEvaluated) {...} but i want only 1 function GetDBValue for nullables. How do I do that and keep the call as is is? Is that possible at all? I can make it work like: public static object GetDBValue<T>(Nullable<T> ObjectEvaluated) where T : struct { if (ObjectEvaluated.HasValue) return ObjectEvaluated.Value; else return DBNull.Value; } But the call changes to: Params.Add(new SqlParameter("@EntityID ", GetDBValue<int>(EntityID)));

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  • Better way to ignore exception type: multiple catch block vs. type querying

    - by HuBeZa
    There are situations that we like to ignore a specific exception type (commonly ObjectDisposedException). It can be achieved with those two methods: try { // code that throws error here: } catch (SpecificException) { /*ignore this*/ } catch (Exception ex) { // Handle exception, write to log... } or try { // code that throws error here: } catch (Exception ex) { if (ex is SpecificException) { /*ignore this*/ } else { // Handle exception, write to log... } } What are the pros and cons of this two methods (regarding performance, readability, etc.)?

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  • Effective Data Validation

    - by John Conde
    What's an effective way to handle data validation, say, from a form submission? Originally I had a bunch of if statements that checked each value and collected invalid values in an array for later retrieval (and listing). // Store errors here $errors = array(); // Hypothetical check if a string is alphanumeric if (!preg_match('/^[a-z\d]+$/i', $fieldvalue)) { $errors[$fieldname] = 'Please only use letters and numbers for your street address'; } // etc... What I did next was create a class that handles various data validation scenarios and store the results in an internal array. After data validation was complete I would check to see if any errors occurred and handle accordingly: class Validation { private $errorList = array(); public function isAlphaNumeric($string, $field, $msg = '') { if (!preg_match('/^[a-z\d]+$/i', $string)) { $this->errorList[$field] = $msg; } } // more methods here public function creditCard($cardNumber, $field, $msg = '') { // Validate credit card number } // more methods here public function hasErrors() { return count($this->errorList); } } /* Client code */ $validate = new Validation(); $validate->isAlphaNumeric($fieldvalue1, $fieldname1, 'Please only use letters and numbers for your street address'); $validate->creditCard($fieldvalue2, $fieldname2, 'Please enter a valid credit card number'); if ($validate->hasErrors()) { // Handle as appropriate } Naturally it didn't take long before this class became bloated with the virtually unlimited types of data to be validated. What I'm doing now is using decorators to separate the different types of data into their own classes and call them only when needed leaving generic validations (i.e. isAlphaNumeric()) in the base class: class Validation { private $errorList = array(); public function isAlphaNumeric($string, $field, $msg = '') { if (!preg_match('/^[a-z\d]+$/i', $string)) { $this->errorList[$field] = $msg; } } // more generic methods here public function setError($field, $msg = '') { $this->errorList[$field] = $msg; } public function hasErrors() { return count($this->errorList); } } class ValidationCreditCard { protected $validate; public function __construct(Validation $validate) { $this->validate = $validate; } public function creditCard($cardNumber, $field, $msg = '') { // Do validation // ... // if there is an error $this->validate->setError($field, $msg); } // more methods here } /* Client code */ $validate = new Validation(); $validate->isAlphaNumeric($fieldvalue, $fieldname, 'Please only use letters and numbers for your street address'); $validateCC = new ValidationCreditCard($validate); $validateCC->creditCard($fieldvalue2, $fieldname2, 'Please enter a valid credit card number'); if ($validate->hasErrors()) { // Handle as appropriate } Am I on the right track? Or did I just complicate data validation more then I needed to?

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  • T-SQL generated from LINQ to SQL is missing a where clause

    - by Jimmy W
    I have extended some functionality to a DataContext object (called "CodeLookupAccessDataContext") such that the object exposes some methods to return results of LINQ to SQL queries. Here are the methods I have defined: public List<CompositeSIDMap> lookupCompositeSIDMap(int regionId, int marketId) { var sidGroupId = CompositeSIDGroupMaps.Where(x => x.RegionID.Equals(regionId) && x.MarketID.Equals(marketId)) .Select(x => x.CompositeSIDGroup); IEnumerator<int> sidGroupIdEnum = sidGroupId.GetEnumerator(); if (sidGroupIdEnum.MoveNext()) return lookupCodeInfo<CompositeSIDMap, CompositeSIDMap>(x => x.CompositeSIDGroup.Equals(sidGroupIdEnum.Current), x => x); else return null; } private List<TResult> lookupCodeInfo<T, TResult>(Func<T, bool> compLambda, Func<T, TResult> selectLambda) where T : class { System.Data.Linq.Table<T> dataTable = this.GetTable<T>(); var codeQueryResult = dataTable.Where(compLambda) .Select(selectLambda); List<TResult> codeList = new List<TResult>(); foreach (TResult row in codeQueryResult) codeList.Add(row); return codeList; } CompositeSIDGroupMap and CompositeSIDMap are both tables in our database that are represented as objects in my DataContext object. I wrote the following code to call these methods and display the T-SQL generated after calling these methods: using (CodeLookupAccessDataContext codeLookup = new CodeLookupAccessDataContext()) { codeLookup.Log = Console.Out; List<CompositeSIDMap> compList = codeLookup.lookupCompositeSIDMap(5, 3); } I got the following results in my log after invoking this code: SELECT [t0].[CompositeSIDGroup] FROM [dbo].[CompositeSIDGroupMap] AS [t0] WHERE ([t0].[RegionID] = @p0) AND ([t0].[MarketID] = @p1) -- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [5] -- @p1: Input Int (Size = 0; Prec = 0; Scale = 0) [3] -- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.30729.1 SELECT [t0].[PK_CSM], [t0].[CompositeSIDGroup], [t0].[InputSID], [t0].[TargetSID], [t0].[StartOffset], [t0].[EndOffset], [t0].[Scale] FROM [dbo].[CompositeSIDMap] AS [t0] -- Context: SqlProvider(Sql2005) Model: AttributedMetaModel Build: 3.5.30729.1 The first T-SQL statement contains a where clause as specified and returns one column as expected. However, the second statement is missing a where clause and returns all columns, even though I did specify which rows I wanted to view and which columns were of interest. Why is the second T-SQL statement generated the way it is, and what should I do to ensure that I filter out the data according to specifications via the T-SQL? Also note that I would prefer to keep lookupCodeInfo() and especially am interested in keeping it enabled to accept lambda functions for specifying which rows/columns to return.

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  • Java Trying to get a line of source from a website

    - by dsta
    I'm trying to get one line of source from a website and then I'm returning that line back to main. I keep on getting an error at the line where I define InputStream in. Why am I getting an error at this line? public class MP3LinkRetriever { private static String line; public static void main(String[] args) { String link = "www.google.com"; String line = ""; while (link != "") { link = JOptionPane.showInputDialog("Please enter the link"); try { line = Connect(link); } catch(Exception e) { } JOptionPane.showMessageDialog(null, "MP3 Link: " + parseLine(line)); String text = line; Toolkit.getDefaultToolkit( ).getSystemClipboard() .setContents(new StringSelection(text), new ClipboardOwner() { public void lostOwnership(Clipboard c, Transferable t) { } }); JOptionPane.showMessageDialog(null, "Link copied to your clipboard"); } } public static String Connect(String link) throws Exception { String strLine = null; InputStream in = null; try { URL url = new URL(link); HttpURLConnection uc = (HttpURLConnection) url.openConnection(); in = new BufferedInputStream(uc.getInputStream()); Reader re = new InputStreamReader(in); BufferedReader r = new BufferedReader(re); int index = -1; while ((strLine = r.readLine()) != null && index == -1) { index = strLine.indexOf("<source src"); } } finally { try { in.close(); } catch (Exception e) { } } return strLine; } public static String parseLine(String line) { line = line.replace("<source", ""); line = line.replace(" src=", ""); line = line.replace("\"", ""); line = line.replace("type=", ""); line = line.replace("audio/mpeg", ""); line = line.replace(">", ""); return line; } }

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  • Linked lists in Java - help with assignment

    - by user368241
    Representation of a string in linked lists In every intersection in the list there will be 3 fields : The letter itself. The number of times it appears consecutively. A pointer to the next intersection in the list. The following class CharNode represents a intersection in the list : public class CharNode { private char _data; private int _value; private charNode _next; public CharNode (char c, int val, charNode n) { _data = c; _value = val; _next = n; } public charNode getNext() { return _next; } public void setNext (charNode node) { _next = node; } public int getValue() { return _value; } public void setValue (int v) { value = v; } public char getData() { return _data; } public void setData (char c) { _data = c; } } The class StringList represents the whole list : public class StringList { private charNode _head; public StringList() { _head = null; } public StringList (CharNode node) { _head = node; } } Add methods to the class StringList according to the details : (I will add methods gradually according to my specific questions) (Pay attention, these are methods from the class String and we want to fulfill them by the representation of a string by a list as explained above) public int indexOf (int ch) - returns the index in the string it is operated on of the first appeareance of the char "ch". If the char "ch" doesn't appear in the string, returns -1. If the value of fromIndex isn't in the range, returns -1. Pay attention to all the possible error cases. Write what is the time complexity and space complexity of every method that you wrote. Make sure the methods you wrote are effective. It is NOT allowed to use ready classes of Java. It is NOT allowed to move to string and use string operations. Here is my try to write the method indexOf (int ch). Kindly assist me with fixing the bugs so I can move on. public int indexOf (int ch) { int count = 0; charNode pose = _head; if (pose == null ) { return -1; } for (pose = _head; pose!=null && pose.getNext()!='ch'; pose = pose.getNext()) { count++; } if (pose!=null) return count; else return -1; }

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  • passing an "unknown enumeration" to a method

    - by firoso
    I'm currently trying to make a class that can register strings as identifiers and accociate them with different types of Enumerations, these enumerations are being evaluated only in so much that I am ensuring that when it's used, that the parameter passed to broadcast (messageType) is an instance of the associated Enum Type. This would work something like this: Diagnostics.RegisterIdentifier("logger", typeof(TestEnum)); Diagnostics.Broadcast("logger", TestEnum.Info, null, "Hello World", null); here's the code I currently have, I need to be able to verify that messageTypesEnum is contained in messageTypesFromIdentifier. private static Dictionary<string, Type> identifierMessageTypeMapping = new Dictionary<string, Type>(); private static List<IListener> listeners = new List<IListener>(); public static void RegisterIdentifier(string identifier, Type messageTypesEnum) { if (messageTypesEnum.BaseType.FullName == "System.Enum") { identifierMessageTypeMapping.Add(identifier, messageTypesEnum); } else { throw new ArgumentException("Expected type of messageTypesEnum to derive from System.Enum", "messageTypesEnum"); } } public static void Broadcast(string identifier, object messageType, string metaIdentifier, string message, Exception exception) { if (identifierMessageTypeMapping.ContainsKey(identifier)) { Type messageTypesFromIdentifier = identifierMessageTypeMapping[identifier]; foreach (var listener in listeners) { DiagnosticsEvent writableEvent = new DiagnosticsEvent(identifier, messageType, metaIdentifier, message, exception); listener.Write(writableEvent); } } }

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  • Reference a GNU C DLL built in GCC against Cygwin, from C#/NET

    - by Dale Halliwell
    Here is what I want: I have a huge legacy C/C++ codebase written for POSIX, including some very POSIX specific stuff like pthreads. This can be compiled on Cygwin/GCC and run as an executable under Windows with the Cygwin DLL. What I would like to do is build the codebase itself into a Windows DLL that I can then reference from C# and write a wrapper around it to access some parts of it programatically. I have tried this approach with the very simple "hello world" example at http://www.cygwin.com/cygwin-ug-net/dll.html and it doesn't seem to work. #include <stdio.h> extern "C" __declspec(dllexport) int hello(); int hello() { printf ("Hello World!\n"); return 42; } I believe I should be able to reference a DLL built with the above code in C# using something like: [DllImport("kernel32.dll")] public static extern IntPtr LoadLibrary(string dllToLoad); [DllImport("kernel32.dll")] public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName); [DllImport("kernel32.dll")] public static extern bool FreeLibrary(IntPtr hModule); [UnmanagedFunctionPointer(CallingConvention.Cdecl)] private delegate int hello(); static void Main(string[] args) { var path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "helloworld.dll"); IntPtr pDll = LoadLibrary(path); IntPtr pAddressOfFunctionToCall = GetProcAddress(pDll, "hello"); hello hello = (hello)Marshal.GetDelegateForFunctionPointer( pAddressOfFunctionToCall, typeof(hello)); int theResult = hello(); Console.WriteLine(theResult.ToString()); bool result = FreeLibrary(pDll); Console.ReadKey(); } But this approach doesn't seem to work. LoadLibrary returns null. It can find the DLL (helloworld.dll), it is just like it can't load it or find the exported function. I am sure that if I get this basic case working I can reference the rest of my codebase in this way. Any suggestions or pointers, or does anyone know if what I want is even possible? Thanks.

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  • What is the meaning of method class in the class definition in Ruby?

    - by Steven Xu
    I'm familiar with function definitions and variable declarations being in class definitions: public class MyClass { public int myvar; public void doSomething() { } } But what does it "mean" in Ruby when a method is actually called in the class definition? This happens amply in Rails, for instance: class User < ActiveRecord::Base has_many :posts end What exactly does this do (at a lower level than "it adds some methods to the class")? How would I implement such a function (e.g., one that mixes in some additional methods)?

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  • Naming conventions for complex getters in Java

    - by Simon
    Hi there! I was reading this C# article about the usage of properties and methods. It points out why and when to use properties or methods. Properties are meant to be used like fields, meaning that properties should not be computationally complex or produce side effects I was asking myself how you could express this difference in Java, where you only use getters for the retrieval of data. What is your opinion?

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