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  • When is it better to use a method versus a property for a class definition?

    - by ccomet
    Partially related to an earlier question of mine, I have a system in which I have to store complex data as a string. Instead of parsing these strings as all kinds of separate objects, I just created one class that contains all of those objects, and it has some parser logic that will encode all properties into strings, or decode a string to get those objects. That's all fine and good. This question is not about the parser itself, but about where I should house the logic for the parser. Is it a better choice to put it as a property, or as a method? In the case of a property, say public string DataAsString, the get accessor would house the logic to encode all of the data into a string, while the set accessor would decode the input value and set all of the data in the class instance. It seems convenient because the input/output is indeed a string. In the case of a method, one method would be Encode(), which returns the encoded string. Then, either the constructor itself would house the logic for the decoding a string and require the string argument, or I write a Decode(string str) method which is called separately. In either case, it would be using a method instead of a property. So, is there a functional difference between these paths, in terms of the actual running of the code? Or are they basically equivalent and it then boils down to a choice of personal preference or which one looks better? And in that kind of question... which would look cleaner anyway?

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  • Access cost of dynamically created objects with dynamically allocated members

    - by user343547
    I'm building an application which will have dynamic allocated objects of type A each with a dynamically allocated member (v) similar to the below class class A { int a; int b; int* v; }; where: The memory for v will be allocated in the constructor. v will be allocated once when an object of type A is created and will never need to be resized. The size of v will vary across all instances of A. The application will potentially have a huge number of such objects and mostly need to stream a large number of these objects through the CPU but only need to perform very simple computations on the members variables. Could having v dynamically allocated could mean that an instance of A and its member v are not located together in memory? What tools and techniques can be used to test if this fragmentation is a performance bottleneck? If such fragmentation is a performance issue, are there any techniques that could allow A and v to allocated in a continuous region of memory? Or are there any techniques to aid memory access such as pre-fetching scheme? for example get an object of type A operate on the other member variables whilst pre-fetching v. If the size of v or an acceptable maximum size could be known at compile time would replacing v with a fixed sized array like int v[max_length] lead to better performance? The target platforms are standard desktop machines with x86/AMD64 processors, Windows or Linux OSes and compiled using either GCC or MSVC compilers.

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  • ASP.NET MVC unit testing

    - by Simon Lomax
    Hi, I'm getting started with unit testing and trying to do some TDD. I've read a fair bit about the subject and written a few tests. I just want to know if the following is the right approach. I want to add the usual "contact us" facility on my web site. You know the thing, the user fills out a form with their email address, enters a brief message and hits a button to post the form back. The model binders do their stuff and my action method accepts the posted data as a model. The action method would then parse the model and use smtp to send an email to the web site administrator infoming him/her that somebody filled out the contact form on their site. Now for the question .... In order to test this, would I be right in creating an interface IDeliver that has a method Send(emailAddress, message) to accept the email address and message body. Implement the inteface in a concrete class and let that class deal with smtp stuff and actually send the mail. If I add the inteface as a parameter to my controller constructor I can then use DI and IoC to inject the concrete class into the controller. But when unit testing I can create a fake or mock version of my IDeliver and do assertions on that. The reason I ask is that I've seen other examples of people generating interfaces for SmtpClient and then mocking that. Is there really any need to go that far or am I not understanding this stuff?

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  • Python - wxPython custom button -> unbound method __init__()? what?

    - by Wallter
    After looking at questions like this it doesn't make sense that my __init__(self, parrent, id) would be throwing a unbound error? help? main.py import wx from customButton import customButton from wxPython.wx import * class MyFrame(wx.Frame): def __init__(self, parent, ID, title): wxFrame.__init__(self, parent, ID, title, wxDefaultPosition, wxSize(400, 400)) # Non-important code here... # This is the first declaration of the Button1 # This is also where the ERROR is thrown. # Omitting this line causes the window to execute # flawlessly. self.Button1 = customButton.__init__(self, parent, -1) # ... finishes in a basic wx.program style... customButton.py # I've included all of the code in the file # because have no idea where the bug/error happens import wx from wxPython.wx import * class Custom_Button(wx.PyControl): # The BMP's Over_bmp = None #wxEmptyBitmap(1,1,1) # When the mouse is over Norm_bmp = None #wxEmptyBitmap(1,1,1) # The normal BMP Push_bmp = None #wxEmptyBitmap(1,1,1) # The down BMP def __init__(self, parent, id, **kwargs): wx.PyControl.__init__(self,parent, id, **kwargs) # Set the BMP's to the ones given in the constructor #self.Over_bmp = wx.Bitmap(wx.Image(MOUSE_OVER_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Norm_bmp = wx.Bitmap(wx.Image(NORM_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Push_bmp = wx.Bitmap(wx.Image(PUSH_BMP, wx.BITMAP_TYPE_ANY).ConvertToBitmap()) #self.Pos_bmp = self.pos self.Bind(wx.EVT_LEFT_DOWN, self._onMouseDown) self.Bind(wx.EVT_LEFT_UP, self._onMouseUp) self.Bind(wx.EVT_LEAVE_WINDOW, self._onMouseLeave) self.Bind(wx.EVT_ENTER_WINDOW, self._onMouseEnter) self.Bind(wx.EVT_ERASE_BACKGROUND,self._onEraseBackground) self.Bind(wx.EVT_PAINT,self._onPaint) self._mouseIn = self._mouseDown = False def _onMouseEnter(self, event): self._mouseIn = True def _onMouseLeave(self, event): self._mouseIn = False def _onMouseDown(self, event): self._mouseDown = True def _onMouseUp(self, event): self._mouseDown = False self.sendButtonEvent() def sendButtonEvent(self): event = wx.CommandEvent(wx.wxEVT_COMMAND_BUTTON_CLICKED, self.GetId()) event.SetInt(0) event.SetEventObject(self) self.GetEventHandler().ProcessEvent(event) def _onEraseBackground(self,event): # reduce flicker pass def _onPaint(self, event): dc = wx.BufferedPaintDC(self) dc.SetFont(self.GetFont()) dc.SetBackground(wx.Brush(self.GetBackgroundColour())) dc.Clear() dc.DrawBitmap(self.Norm_bmp) # draw whatever you want to draw # draw glossy bitmaps e.g. dc.DrawBitmap if self._mouseIn: # If the Mouse is over the button dc.DrawBitmap(self, self.Mouse_over_bmp, self.Pos_bmp, useMask=False) if self._mouseDown: # If the Mouse clicks the button dc.DrawBitmap(self, self.Push_bmp, self.Pos_bmp, useMask=False)

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  • get eigenvalue pca with java

    - by Muhamad Burhanudin
    I try use PCA to reduce dimention, and i use jama for help me using matrix. but, i got problem when get eigenvalue with jama. for example i hava 2 image dimention 100x100, then i create single matrix 2 image x (100x100). there is 20.000 pixel. and how to get reduction with eigenvalue? this is sample my code : public static void main(String[] args) { BufferedImage bi; int[] rgb; int R, G, B; // int[] jum; double[][] gray = new double[500][500] ; String[] baris = new String[1000]; try { //bi = ImageIO.read(new File("D:\\c.jpg")); int[][] pixelData = new int[bi.getHeight() * bi.getWidth()][3]; int counter = 0; for (int i = 0; i < bi.getHeight(); i++) { for (int j = 0; j < bi.getWidth(); j++) { gray[i][j] = getPixelData(bi, i, j); // R = getR(bi, i, j); //G = getG(bi, i, j); //B = getB(bi, i, j); //jum = R + G + B; // gray[counter] = Double.toString(R + G + B / 3); // System.out.println("Gray " +gray); //for (int k = 0; k < rgb.length; k++) { // pixelData[counter][k] = rgb[k]; // } counter++; } } } catch (IOException e) { e.printStackTrace(); } Matrix matrix = new Matrix(gray); PCA pca = new PCA(matrix); pca.getEigenvalue(6); String n = pca.toString(); System.err.println("nilai n "+n); //double dete = pcadete(matrix,3600); } private static int getPixelData(BufferedImage bi, int x, int y) { int argb = bi.getRGB(y, x); int r, g, b; int gray; int rgb[] = new int[]{ (argb >> 16) & 0xff, //red (argb >> 8) & 0xff, //green (argb) & 0xff //blue }; r = rgb[0]; g = rgb[1]; b = rgb[2]; gray = (r + g + b) / 3; System.out.println("gray: " + gray); return gray; } when i show eigenvalue in this code : PCA pca = new PCA(matrix); pca.getEigenvalue(6); String n = pca.toString(); System.err.println("nilai n "+n); Result is : nilai n PCA@c3e9e9 Can, u tell me what way to get eigenvalue and reduction dimension.

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  • Is there a tool I can use to generate interfaces and wrappers for object mocking in c#

    - by fostandy
    Given a class like System.Timers.Timer, or ANY managed class (whether user defined, from the .net framework, or some 3rd party library) is there some program I can use to (a) generate an interface based on this class and (b) generate a wrapper for the given class? for example if I have a public class Foo { public object MyProperty { get { ... } set { ... } } public int SomeMethod(object a) { ... } } it will create an interface interface IFoo { object MyProperty { get; set; } int SomeMethod(object a) { ... } } and maybe even a wrapper class FooWrap { // something for relay constructor here ... Foo _me; public object MyProperty { get { return _me.MyProperty; } set { _me.MyProperty = value; } } public int SomeMethod(object a) { return _me.SomeMethod(); } } Obviously there's stuff I haven't thought about like events, generics etc. I want a DWIMNWIS-PSICHTO(-Plus-Stuff-I-Clearly-Haven't-Thought-Of). I'm aware resharper can be used to extract an interface but I've only been able to use this on my own classes. Aside: Wow, it is amazing how simply becoming accustomed to a previously 'unacceptable' idea eventually gives it legitimacy. A year ago the idea of having to create interfaces for all objects I want to mock and adopting an injection framework would have seemed like the height of madness. It turns out that while it's not quite death and taxes, it is sparta. I am aware of and have used typemock. It certainly is the work of elvish wizards. One day when $800 does not seem like quite so much money I intend to buy it.

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  • How can "today's date" be varied for unit testing purposes?

    - by ck
    I use VS2008 targetting .NET 2.0 Framework, and, just in case, no I can't change this :) I have a DateCalculator class. Its method GetNextExpirationDate attempts to determine the next expiration, internally using DateTime.Today as a baseline date. As I was writing unit tests, I realized that I wanted to test GetNextExpirationDate for different 'today' dates. What's the best way to do this? Here are some alternatives I've considered: Expose a property/overloaded method with argument baselineDate and only use it from the unit test. In actual client code, disregard the property/overloaded method in favour of the method that defaults baselineDate to DateTime.Today. I'm reluctant to do this as it makes the public interface of the DateCalculator class awkward. Create a protected field called baselineDate that is internally set to DateTime.Today. When testing, derive a DateCalculatorForTesting from DateCalculator and set baslineDate via the constructor. It keeps the public interface clean, but still isn't great - baselineDate was made protected and a derived class is required, both solely for testing. Use extension methods. I tried this after adding the ExtensionAttribute, then realized it wouldn't work because extension methods can't access private/protected variables. I initially thought this was really quite an elegant solution. :( I'd be interested in hearing what others think.

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  • C# Asynchronous Network IO and OutOfMemoryException

    - by The.Anti.9
    I'm working on a client/server application in C#, and I need to get Asynchronous sockets working so I can handle multiple connections at once. Technically it works the way it is now, but I get an OutOfMemoryException after about 3 minutes of running. MSDN says to use a WaitHandler to do WaitOne() after the socket.BeginAccept(), but it doesn't actually let me do that. When I try to do that in the code it says WaitHandler is an abstract class or interface, and I can't instantiate it. I thought maybe Id try a static reference, but it doesnt have teh WaitOne() method, just WaitAll() and WaitAny(). The main problem is that in the docs it doesn't give a full code snippet, so you can't actually see what their "wait handler" is coming from. its just a variable called allDone, which also has a Reset() method in the snippet, which a waithandler doesn't have. After digging around in their docs, I found some related thing about an AutoResetEvent in the Threading namespace. It has a WaitOne() and a Reset() method. So I tried that around the while(true) { ... socket.BeginAccept( ... ); ... }. Unfortunately this makes it only take one connection at a time. So I'm not really sure where to go. Here's my code: class ServerRunner { private Byte[] data = new Byte[2048]; private int size = 2048; private Socket server; static AutoResetEvent allDone = new AutoResetEvent(false); public ServerRunner() { server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); IPEndPoint iep = new IPEndPoint(IPAddress.Any, 33333); server.Bind(iep); Console.WriteLine("Server initialized.."); } public void Run() { server.Listen(100); Console.WriteLine("Listening..."); while (true) { //allDone.Reset(); server.BeginAccept(new AsyncCallback(AcceptCon), server); //allDone.WaitOne(); } } void AcceptCon(IAsyncResult iar) { Socket oldserver = (Socket)iar.AsyncState; Socket client = oldserver.EndAccept(iar); Console.WriteLine(client.RemoteEndPoint.ToString() + " connected"); byte[] message = Encoding.ASCII.GetBytes("Welcome"); client.BeginSend(message, 0, message.Length, SocketFlags.None, new AsyncCallback(SendData), client); } void SendData(IAsyncResult iar) { Socket client = (Socket)iar.AsyncState; int sent = client.EndSend(iar); client.BeginReceive(data, 0, size, SocketFlags.None, new AsyncCallback(ReceiveData), client); } void ReceiveData(IAsyncResult iar) { Socket client = (Socket)iar.AsyncState; int recv = client.EndReceive(iar); if (recv == 0) { client.Close(); server.BeginAccept(new AsyncCallback(AcceptCon), server); return; } string receivedData = Encoding.ASCII.GetString(data, 0, recv); //process received data here byte[] message2 = Encoding.ASCII.GetBytes("reply"); client.BeginSend(message2, 0, message2.Length, SocketFlags.None, new AsyncCallback(SendData), client); } }

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  • What is the best way to use Guice and JMock together?

    - by Yishai
    I have started using Guice to do some dependency injection on a project, primarily because I need to inject mocks (using JMock currently) a layer away from the unit test, which makes manual injection very awkward. My question is what is the best approach for introducing a mock? What I currently have is to make a new module in the unit test that satisfies the dependencies and bind them with a provider that looks like this: public class JMockProvider<T> implements Provider<T> { private T mock; public JMockProvider(T mock) { this.mock = mock; } public T get() { return mock; } } Passing the mock in the constructor, so a JMock setup might look like this: final CommunicationQueue queue = context.mock(CommunicationQueue.class); final TransactionRollBack trans = context.mock(TransactionRollBack.class); Injector injector = Guice.createInjector(new AbstractModule() { @Override protected void configure() { bind(CommunicationQueue.class).toProvider(new JMockProvider<QuickBooksCommunicationQueue>(queue)); bind(TransactionRollBack.class).toProvider(new JMockProvider<TransactionRollBack>(trans)); } }); context.checking(new Expectations() {{ oneOf(queue).retrieve(with(any(int.class))); will(returnValue(null)); never(trans); }}); injector.getInstance(RunResponse.class).processResponseImpl(-1); Is there a better way? I know that AtUnit attempts to address this problem, although I'm missing how it auto-magically injects a mock that was created locally like the above, but I'm looking for either a compelling reason why AtUnit is the right answer here (other than its ability to change DI and mocking frameworks around without changing tests) or if there is a better solution to doing it by hand.

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  • How can I check if a user has written his username and password correctly?

    - by Sergio Tapia
    I'm using a Linq-to-SQL class called Scans.dbml. In that class I've dragged a table called Users (username, password, role) onto the graphic area and now I can access User object via a UserRepository class: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Scanner.Classes { public class UserRepository { private ScansDataContext db = new ScansDataContext(); public User getUser(string username) { return db.Users.SingleOrDefault(x => x.username == username); } public bool exists(string username) { } } } Now in my Login form, I want to use this Linq-to-SQL goodness to do all the data related activities. UserRepository users = new UserRepository(); private void btnLogin_Click(object sender, EventArgs e) { loginToSystem(); } private void loginToSystem() { if (users.getUser(txtUsername.Text)) { } //If txtUsername exists && User.password == Salt(txtPassword) //then Show.MainForm() with User.accountType in constructor to set permissions. } I need help with verifying that a user exists && that that users.password is equal to SALT(txtpassword.text). Any guidance please?

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  • Custom pager in my Gridview 1st time works, next doesn't :

    - by gre3ns0ul
    Hi guys, i'm with one strange problem. I am extending a control from a Gridview, and adding a dropdown to paging to the page i want. In my custom gridview i added a ITemplate than contains 4 image buttons and one dropdownlist (4 images - 1st, prev, next, last) (1 ddl - to page) and add him to my custom gridview.. I added a selectindexchange event to dropdown, to fire when a index is changed The problem is: The first time i load the page with my control it is really ok.. but when i change index, in debug i see to run constructor of control, creating footer template, and guess.. the method of indexchange isn't fired and returns an exception saying: Unable to cast object of type 'System.Web.UI.WebControls.ImageButton' to type 'System.Web.UI.WebControls.Table'. [InvalidCastException: Unable to cast object of type 'System.Web.UI.WebControls.ImageButton' to type 'System.Web.UI.WebControls.Table'.] System.Web.UI.WebControls.GridView.PrepareControlHierarchy() +122 System.Web.UI.WebControls.GridView.Render(HtmlTextWriter writer, Boolean renderPanel) +50 System.Web.UI.WebControls.GridView.Render(HtmlTextWriter writer) +33 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 ... apreciate for the help, thanks

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  • why does this boost::spirit::qi rule not work?

    - by Tobias Langner
    I have a grammar that defines the following rules: constantValue = qi::token(ID_FLOAT) | qi::token(ID_INTEGER); postfixExpression = primaryExpression | (postfixExpression >> qi::token(ID_OPENBRACKET) >> qi::token(ID_INTEGER) >> qi::token(ID_CLOSEBRACKET)) | (postfixExpression >> qi::token(ID_DOT) >> qi::token(ID_IDENTIFIER)); primaryExpression = qi::token(ID_IDENTIFIER) | constantValue | (qi::token(ID_OPENPAREN) >> primaryExpression >> qi::token(ID_CLOSEPAREN)); ges = postfixExpression >> qi::eoi; and I want it to match the following strings: test[1] testident.ident and it should not match test[1.2] testident.5 but it fails to match the first 2 strings. The lexer constructor is as follows: custom_lexer() : identifier("[a-zA-Z_][a-zA-Z0-9_]*") , white_space("[ \\t\\n]+") , integer_value("[1-9][0-9]*") , hex_value("0[xX][0-9a-fA-F]+") , float_value("[0-9]*\\.[0-9]+([eE][+-]?[0-9]+)?") , float_value2("[0-9]+\\.([eE][+-]?[0-9]+)?") , punctuator("&>|\\*\\*|\\*|\\+|-|~|!|\\/|%|<<|>>|<|>|<=|>=|==|!=|\\^|&|\\||\\^\\^|&&|\\|\\||\\?|:|,")// [ ] ( ) . &> ** * + - ~ ! / % << >> < > <= >= == != ^ & | ^^ && || ? : , { using boost::spirit::lex::_start; using boost::spirit::lex::_end; this->self.add (identifier, ID_IDENTIFIER) /*(white_space, ID_WHITESPACE)*/ (integer_value, ID_INTEGER) (hex_value, ID_INTEGER) (float_value, ID_FLOAT) (float_value2, ID_FLOAT) ("\\(", ID_OPENPAREN) ("\\)", ID_CLOSEPAREN) ("\\[", ID_OPENBRACKET) ("\\]", ID_CLOSEBRACKET) ("\\.", ID_DOT) (punctuator, ID_PUNCTUATOR) ; this->self("WS") = white_space; } Why don't I get a match for the mentioned strings? Thank you Tobias

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  • Java: Implement own message queue (threadsafe)

    - by derMax
    The task is to implement my own messagequeue that is thread safe. My approach: public class MessageQueue { /** * Number of strings (messages) that can be stored in the queue. */ private int capacity; /** * The queue itself, all incoming messages are stored in here. */ private Vector<String> queue = new Vector<String>(capacity); /** * Constructor, initializes the queue. * * @param capacity The number of messages allowed in the queue. */ public MessageQueue(int capacity) { this.capacity = capacity; } /** * Adds a new message to the queue. If the queue is full, it waits until a message is released. * * @param message */ public synchronized void send(String message) { //TODO check } /** * Receives a new message and removes it from the queue. * * @return */ public synchronized String receive() { //TODO check return "0"; } } If the queue is empty and I call remove(), I want to call wait() so that another thread can use the send() method. Respectively, I have to call notifyAll() after every iteration. Question: Is that possible? I mean does it work that when I say wait() in one method of an object, that I can then execute another method of the same object? And another question: Does that seem to be clever?

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  • Why is this attempt at a binary search crashing?

    - by Ian Campbell
    I am fairly new to the concept of a binary search, and am trying to write a program that does this in Java for personal practice. I understand the concept of this well, but my code is not working. There is a run-time exception happening in my code that just caused Eclipse, and then my computer, to crash... there are no compile-time errors here though. Here is what I have so far: public class BinarySearch { // instance variables int[] arr; int iterations; // constructor public BinarySearch(int[] arr) { this.arr = arr; iterations = 0; } // instance method public int findTarget(int targ, int[] sorted) { int firstIndex = 1; int lastIndex = sorted.length; int middleIndex = (firstIndex + lastIndex) / 2; int result = sorted[middleIndex - 1]; while(result != targ) { if(result > targ) { firstIndex = middleIndex + 1; middleIndex = (firstIndex + lastIndex) / 2; result = sorted[middleIndex - 1]; iterations++; } else { lastIndex = middleIndex + 1; middleIndex = (firstIndex + lastIndex) / 2; result = sorted[middleIndex - 1]; iterations++; } } return result; } // main method public static void main(String[] args) { int[] sortedArr = new int[] { 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29 }; BinarySearch obj = new BinarySearch(sortedArr); int target = sortedArr[8]; int result = obj.findTarget(target, sortedArr); System.out.println("The original target was -- " + target + ".\n" + "The result found was -- " + result + ".\n" + "This took " + obj.iterations + " iterations to find."); } // end of main method } // end of class BinarySearch

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  • Interface for reading variable length files with header and footer.

    - by John S
    I could use some hints or tips for a decent interface for reading file of special characteristics. The files in question has a header (~120 bytes), a body (1 byte - 3gb) and a footer (4 bytes). The header contains information about the body and the footer is only a simple CRC32-value of the body. I use Java so my idea was to extend the "InputStream" class and add a constructor such as "public MyInStream( InputStream in)" where I immediately read the header and the direct the overridden read()'s the body. Problem is, I can't give the user of the class the CRC32-value until the whole body has been read. Because the file can be 3gb large, putting it all in memory is a be an idea. Reading it all in to a temporary file is going to be a performance hit if there are many small files. I don't know how large the file is because the InputStream doesn't have to be a file, it could be a socket. Looking at it again, maybe extending InputStream is a bad idea. Thank you for reading the confused thoughts of a tired programmer. :)

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  • java: can't use constructors in abstract class

    - by ufk
    Hi. I created the following abstract class for job scheduler in red5: package com.demogames.jobs; import com.demogames.demofacebook.MysqlDb; import org.red5.server.api.IClient; import org.red5.server.api.IConnection; import org.red5.server.api.IScope; import org.red5.server.api.scheduling.IScheduledJob; import org.red5.server.api.so.ISharedObject; import org.apache.log4j.Logger; import org.red5.server.api.Red5; /** * * @author ufk */ abstract public class DemoJob implements IScheduledJob { protected IConnection conn; protected IClient client; protected ISharedObject so; protected IScope scope; protected MysqlDb mysqldb; protected static org.apache.log4j.Logger log = Logger .getLogger(DemoJob.class); protected DemoJob (ISharedObject so, MysqlDb mysqldb){ this.conn=Red5.getConnectionLocal(); this.client = conn.getClient(); this.so=so; this.mysqldb=mysqldb; this.scope=conn.getScope(); } protected DemoJob(ISharedObject so) { this.conn=Red5.getConnectionLocal(); this.client=this.conn.getClient(); this.so=so; this.scope=conn.getScope(); } protected DemoJob() { this.conn=Red5.getConnectionLocal(); this.client=this.conn.getClient(); this.scope=conn.getScope(); } } Then i created a simple class that extends the previous one: public class StartChallengeJob extends DemoJob { public void execute(ISchedulingService service) { log.error("test"); } } The problem is that my main application can only see the constructor without any parameters. with means i can do new StartChallengeJob() why doesn't the main application sees all the constructors ? thanks!

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  • Swig C++ Lua Pass class by reference

    - by Jeremy
    I don't know why I'm having a hard time with this. All I want to do is this: class foo { public: foo(){} ~foo(){} float a,b; }; class foo2 { public: foo2(){} foo2(const foo &f){*this = f;} ~foo2(){} void operator=(const foo& f){ x = f.a; y = f.b; } float x,y; }; /* Usage(cpp): foo f; foo2 f2(f); //or using the = operator f2 = f; */ The problem I'm having is that, after swigging this code, I can't figure out how to make the lua script play nice. /* Usage(lua) f = example.foo() f2 = example.foo2(f) --error */ The error I get is "Wrong arguments for overloaded function 'new_Foo2'": Possible c/c++ prototypes are: foo2() foo2(foo const &) The same thing happens if I try and use do f2 = f. As I understand it everything is stored as a pointer so I did try adding an additional constructor that took a pointer to foo but to no avail.

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  • Why does using Collections.emptySet() with generics work in assignment but not as a method parameter

    - by Karl von L
    So, I have a class with a constructor like this: public FilterList(Set<Integer> labels) { ... } and I want to construct a new FilterList object with an empty set. Following Joshua Bloch's advice in his book Effective Java, I don't want to create a new object for the empty set; I'll just use Collections.emptySet() instead: FilterList emptyList = new FilterList(Collections.emptySet()); This gives me an error, complaining that java.util.Set<java.lang.Object> is not a java.util.Set<java.lang.Integer>. OK, how about this: FilterList emptyList = new FilterList((Set<Integer>)Collections.emptySet()); This also gives me an error! Ok, how about this: Set<Integer> empty = Collections.emptySet(); FilterList emptyList = new FilterList(empty); Hey, it works! But why? After all, Java doesn't have type inference, which is why you get an unchecked conversion warning if you do Set<Integer> foo = new TreeSet() instead of Set<Integer> foo = new TreeSet<Integer>(). But Set<Integer> empty = Collections.emptySet(); works without even a warning. Why is that?

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  • WebClient.DownloadDataAsync is freezing my UI

    - by Matías
    Hi, I have in my Form constructor, after the InitializeComponent the following code: using (WebClient client = new WebClient()) { client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); client.DownloadDataAsync("http://example.com/version.txt"); } When I start my form, the UI doesn't appears till client_DownloadDataCompleted is raised. The client_DownloadDataCompleted method is empty, so there's no problem there. What I'm doing wrong? How is supposed to do this without freezing the UI? Thanks for your time. Best regards. FULL CODE: Program.cs using System; using System.Windows.Forms; namespace Lala { static class Program { /// <summary> /// The main entry point for the application. /// </summary> [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } } Form1.cs using System; using System.Net; using System.Windows.Forms; namespace Lala { public partial class Form1 : Form { WebClient client = new WebClient(); public Form1() { client.DownloadDataCompleted += new DownloadDataCompletedEventHandler(client_DownloadDataCompleted); client.DownloadDataAsync(new Uri("http://www.google.com")); InitializeComponent(); } void client_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e) { textBox1.Text += "A"; } } partial class Form1 { /// <summary> /// Required designer variable. /// </summary> private System.ComponentModel.IContainer components = null; /// <summary> /// Clean up any resources being used. /// </summary> /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { this.button1 = new System.Windows.Forms.Button(); this.textBox1 = new System.Windows.Forms.TextBox(); this.SuspendLayout(); // // button1 // this.button1.Location = new System.Drawing.Point(12, 12); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(75, 23); this.button1.TabIndex = 0; this.button1.Text = "button1"; this.button1.UseVisualStyleBackColor = true; // // textBox1 // this.textBox1.Location = new System.Drawing.Point(12, 41); this.textBox1.Multiline = true; this.textBox1.Name = "textBox1"; this.textBox1.Size = new System.Drawing.Size(468, 213); this.textBox1.TabIndex = 1; // // Form1 // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(492, 266); this.Controls.Add(this.textBox1); this.Controls.Add(this.button1); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); this.PerformLayout(); } #endregion private System.Windows.Forms.Button button1; private System.Windows.Forms.TextBox textBox1; } }

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  • How to Force an Exception from a Task to be Observed in a Continuation Task?

    - by Richard
    I have a task to perform an HttpWebRequest using Task<WebResponse>.Factory.FromAsync(req.BeginGetRespone, req.EndGetResponse) which can obviously fail with a WebException. To the caller I want to return a Task<HttpResult> where HttpResult is a helper type to encapsulate the response (or not). In this case a 4xx or 5xx response is not an exception. Therefore I've attached two continuations to the request task. One with TaskContinuationOptions OnlyOnRanToCompletion and the other with OnlyOnOnFaulted. And then wrapped the whole thing in a Task<HttpResult> to pick up the one result whichever continuation completes. Each of the three child tasks (request plus two continuations) is created with the AttachedToParent option. But when the caller waits on the returned outer task, an AggregateException is thrown is the request failed. I want to, in the on faulted continuation, observe the WebException so the client code can just look at the result. Adding a Wait in the on fault continuation throws, but a try-catch around this doesn't help. Nor does looking at the Exception property (as section "Observing Exceptions By Using the Task.Exception Property" hints here). I could install a UnobservedTaskException event handler to filter, but as the event offers no direct link to the faulted task this will likely interact outside this part of the application and is a case of a sledgehammer to crack a nut. Given an instance of a faulted Task<T> is there any means of flagging it as "fault handled"? Simplified code: public static Task<HttpResult> Start(Uri url) { var webReq = BuildHttpWebRequest(url); var result = new HttpResult(); var taskOuter = Task<HttpResult>.Factory.StartNew(() => { var tRequest = Task<WebResponse>.Factory.FromAsync( webReq.BeginGetResponse, webReq.EndGetResponse, null, TaskCreationOptions.AttachedToParent); var tError = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestError(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnFaulted); var tSuccess = tRequest.ContinueWith<HttpResult>( t => HandleWebRequestSuccess(t, result), TaskContinuationOptions.AttachedToParent |TaskContinuationOptions.OnlyOnRanToCompletion); return result; }); return taskOuter; } with: private static HttpDownloaderResult HandleWebRequestError( Task<WebResponse> respTask, HttpResult result) { Debug.Assert(respTask.Status == TaskStatus.Faulted); Debug.Assert(respTask.Exception.InnerException is WebException); // Try and observe the fault: Doesn't help. try { respTask.Wait(); } catch (AggregateException e) { Log("HandleWebRequestError: waiting on antecedent task threw inner: " + e.InnerException.Message); } // ... populate result with details of the failure for the client ... return result; } (HandleWebRequestSuccess will eventually spin off further tasks to get the content of the response...) The client should be able to wait on the task and then look at its result, without it throwing due to a fault that is expected and already handled.

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  • How to create a new widget for dojox.grid.cells.dijit?

    - by the_drow
    I am trying to create a button widget for dojox.grid. My problems are: 1) The button is only shown when I double click the grid. 2) I can't figure out how to set attributes through declarative markup. It seems that the markupFactory function is responsible for it but it doesn't set the widget's label. The following code demonstrates what I've got so far: dojo.require("dojox.grid.DataGrid"); dojo.require("dojo.data.ItemFileWriteStore"); dojo.require("dijit.form.Button"); dojo.require("dojox.grid.cells.dijit"); dojo.require("dojo.parser"); dojo.declare("dojox.grid.cells.Button", dojox.grid.cells._Widget, { widgetClass: dijit.form.Button, alwaysEditing: true, constructor: function(inCell) { this.inherited(arguments); this.widget = new dijit.form.Button; }, setValue: function(inRowIndex, inValue){ if (this.widget) { this.widget.attr('value', inValue); } else { this.inherited(arguments); } } }); dojox.grid.cells.Button.markupFactory = function(node, cell) { dojox.grid.cells._Widget.markupFactory(node, cell); }

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  • Ladder-like word game in Java

    - by sasquatch90
    I've found this question http://stackoverflow.com/questions/2844190/choosing-design-method-for-ladder-like-word-game and I would also like to do this kind of program. I've written some code but already have two issues. Here's what I already have : GRID : public class Grid { public Grid(){} public Grid( Element e ){} } ELEMENT : public class Element { final int INVISIBLE = 0; final int EMPTY = 1; final int FIRST_LETTER = 2; final int OTHER_LETTER = 3; private int state; private String letter; public Element(){} //empty block public Element(int state){ this("", 0); } //filled block public Element(String s, int state){ this.state = state; this.letter = s; } public static void changeState(int s){ } public int getState(){ return state; } public boolean equalLength(){ return true; } public boolean equalValue(){ return true; } @Override public String toString(){ return "["+letter+"]"; } } MAIN: import java.util.Scanner; public class Main { public static void main(String[] args){ Scanner sc = new Scanner(System.in); System.out.println("Height: "); while (!sc.hasNextInt()) { System.out.println("int, please!"); sc.next(); } final int height = sc.nextInt(); Grid[] game = new Grid[height]; for(int i = 1; i <= height; i++) { String s; do { System.out.println("Length " + i + ", please!"); s = sc.next(); } while (s.length() != i); Element[] line = new Element[s.length()+1]; Element single = null; String[] temp = null; //issue here temp = s.split(""); System.out.println("s.length: "+s.length()); System.out.println("temp.length: "+temp.length); // for(String str : temp){ System.out.println("str:"+str); } for (int k = 0 ; k < temp.length ; k++) { if( k == 0 ){ single = new Element(temp[k], 2); System.out.println("single1: "+single); } else{ single = new Element(temp[k], 3); System.out.println("single2: "+single); } line[k] = single; } for (Element l : line) { System.out.println("line:"+l); } //issue here game[i] = line; } // for (Grid g : game) { System.out.println(g); } } } And sample output for debug : Height: 3 Length 1, please! A s.length: 1 temp.length: 2 str: str:A single1: [] single2: [A] line:[] line:[A] Here's what I think it should work like. I grab a word from user. Next create Grid element for whole game. Then for each line I create Element[] array called line. I split the given text and here's the first problem. Why string.split() adds a whitespace ? You can see clearly in output that it is added for no reason. How can I get rid of it (now I had to add +1 to the length of line just to run the code). Continuing I'm throwing the splitted text into temporary String array and next from each letter I create Element object and throw it to line array. Apart of this empty space output looks fine. But next problem is with Grid. I've created constructor taking Element as an argument, but still I can't throw line as Grid[] elements because of 'incompatible types'. How can I fix that ? Am I even doing it right ? Maybe I should get rid of line as Element[] and just create Grid[][] ?

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  • Scrollbar with Sprite and Rectangle won't move text, just the Rectangle it's painted on.

    - by WebDevHobo
    Warning: school assignment. For those of you still with me, I am tasked with making some scrollable content in Flash. Load in a TextFile using LoadURL(), then display it. To get the text, we've written our own class TextFieldExtended, which is basically just there to give the textfile location to the constructor and then have the class do the various steps of getting it and loading it for you. So I needed to get a Scrollbar, which I got here: http://kirupa.com/forum/showthread.php?t=245468 (all files in a zip linked at the end of this text) The thing is, it works with Sprites. After trying to get it to accept TextFieldExtended, I bumped into a block, since the scrollbar relied heavily on a Sprite property that TextFieldExtended didn't have or could have. So I tried adding the TextFieldExtended instance to a Sprite instance using addchild. A problem occurs here that I do not know how to handle. It seems that a Rectangle is drawn and the Text is drawn on that. I say this because the scrollbar moves the Rectangle up and down a bit, but the text doesn't scroll, just the Rectangle it is positioned in and the text then moves along with it. My question: can this be fixed, or is does this implementation of scrollbars need a lot of adaptations before this is possible? If so, any scrollbars you can recommend, because it's too extended for me at this point. All files: http://www.mediafire.com/?q2ium22gmox This was made in Flash CS4 using ActionScript3. The Example class is the final implementation

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  • Android Google-Shopping API force closes while parsing

    - by Sam Jackson
    I'm trying to send a request to the Google-Shopping API with the following static method which I think is working: public static String GET_TITLE(String url) throws JSONException { InputStream is = null; String result = ""; JSONObject jArray = null; // http post try { HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(url); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); } catch(Exception e) { Log.e("log_tag", "Error in http connection "+e.toString()); } The URL I'm passing is this BTW: https://www.googleapis.com/shopping/search/v1/public/products/country=US&q=shirts&alt=json &rankBy=relevancy&key=AIzaSyDRKgGmJrdG6pV6DIg2m-nmIbXydxvpjww Next I try to parse this response (where I think the problem comes in) in the same method: try { jArray = new JSONObject(result); } catch(JSONException e){ Log.e("log_tag", "Error parsing data "+e.toString()); } JSONObject itemObject = jArray.getJSONObject("items"); JSONObject productObject = itemObject.getJSONObject("product"); String attributeGoogleId = productObject.getString("googleId"); String attributeProviderId = productObject.getString("providerId"); String attributeTitle = productObject.getString("title");*/ String attributePrice = productObject.getString("price"); JSONObject popupObject = productObject.getJSONObject("popup"); return attributeTitle; } This has been so frustrating, I know it should be simple but everywhere I look I just can't quite get it to work, I'm not exactly sure what the error is since I'm testing it on my HTC Desire because my emulator gives an 'invalid command-line parameter' error when starting, but that's a different issue, anyway, thanks in advance! EDIT: The first one makes it look like there's a problem with the URL, should I change it and see if it makes a difference? 04-01 12:09:05.142: ERROR/log_tag(24968): Error in http connection java.net.UnknownHostException: www.googleapis.com 04-01 12:09:05.142: ERROR/log_tag(24968): Error converting result java.lang.NullPointerException 04-01 12:09:05.142: ERROR/log_tag(24968): Error parsing data org.json.JSONException: End of input at character 0 of 04-01 12:09:05.142: DEBUG/AndroidRuntime(24968): Shutting down VM 04-01 12:09:05.142: WARN/dalvikvm(24968): threadid=1: thread exiting with uncaught exception (group=0x400259f8) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): FATAL EXCEPTION: main 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { act=com.google.zxing.client.android.SCAN flg=0x80000 (has extras) }} to activity {com.spectrum.stock/com.spectrum.stock.CaptureActivity}: java.lang.NullPointerException 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread.deliverResults(ActivityThread.java:3734) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3776) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread.access$2800(ActivityThread.java:135) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2166) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.os.Handler.dispatchMessage(Handler.java:99) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.os.Looper.loop(Looper.java:144) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread.main(ActivityThread.java:4937) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at java.lang.reflect.Method.invokeNative(Native Method) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at java.lang.reflect.Method.invoke(Method.java:521) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at dalvik.system.NativeStart.main(Native Method) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): Caused by: java.lang.NullPointerException 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at com.spectrum.stock.JSONResponse.GET_TITLE(JSONResponse.java:61) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at com.spectrum.stock.CaptureActivity.onActivityResult(CaptureActivity.java:78) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.Activity.dispatchActivityResult(Activity.java:3931) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): at android.app.ActivityThread.deliverResults(ActivityThread.java:3730) 04-01 12:09:05.152: ERROR/AndroidRuntime(24968): ... 11 more 04-01 12:09:05.162: WARN/ActivityManager(96): Force finishing activity com.spectrum.stock/.CaptureActivity

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  • Is there a way to automaticly call all versions of an inherited method?

    - by Eric
    I'm writing a plug-in for a 3D modeling program. I have a custom class that wraps instances of elements in the 3D model, and in turn derives it's properties from the element it wraps. When the element in the model changes I want my class(es) to update their properties based on the new geometry. In the simplified example below. I have classes AbsCurveBasd, Extrusion, and Shell which are all derived from one another. Each of these classes implement a RefreshFromBaseShape() method which updates specific properties based on the current baseShape the class is wrapping. I can call base.RefreshFromBaseShape() in each implementation of RefreshFromBaseShape() to ensure that all the properties are updated. But I'm wondering if there is a better way where I don't have to remember to do this in every implementation of RefershFromBaseShape()? For example because AbsCurveBased does not have a parameterless constructor the code wont even compile unless the constructors call the base class constructors. public abstract class AbsCurveBased { internal Curve baseShape; double Area{get;set;} public AbsCurveBased(Curve baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public virtual void RefreshFromBaseShape() { //sets the Area property from the baseShape } } public class Extrusion : AbsCurveBased { double Volume{get;set;} double Height{get;set;} public Extrusion(Curve baseShape):base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public override void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets the Volume property based on the area and the height } } public class Shell : Extrusion { double ShellVolume{get;set;} double ShellThickness{get;set;} public Shell(Curve baseShape): base(baseShape) { this.baseShape = baseShape; RefreshFromBaseShape(); } public void RefreshFromBaseShape() { base.RefreshFromBaseShape(); //sets this Shell Volume from the Extrusion properties and ShellThickness property } }

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