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  • In a class with no virtual methods or superclass, is it safe to assume (address of first member vari

    - by Jeremy Friesner
    Hi all, I made a private API that assumes that the address of the first member-object in the class will be the same as the class's this-pointer... that way the member-object can trivially derive a pointer to the object that it is a member of, without having to store a pointer explicitly. Given that I am willing to make sure that the container class won't inherit from any superclass, won't have any virtual methods, and that the member-object that does this trick will be the first member object declared, will that assumption hold valid for any C++ compiler, or do I need to use the offsetof() operator (or similar) to guarantee correctness? To put it another way, the code below does what I expect under g++, but will it work everywhere? class MyContainer { public: MyContainer() {} ~MyContainer() {} // non-virtual dtor private: class MyContained { public: MyContained() {} ~MyContained() {} // Given that the only place Contained objects are declared is m_contained // (below), will this work as expected on any C++ compiler? MyContainer * GetPointerToMyContainer() { return reinterpret_cast<MyContainer *>(this); } }; MyContained m_contained; // MUST BE FIRST MEMBER ITEM DECLARED IN MyContainer int m_foo; // other member items may be declared after m_contained float m_bar; };

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  • C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

    - by James Michael Hare
    I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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  • Dictionary w/ null key?

    - by Ralph
    Firstly, why doesn't Dictionary<TKey, TValue> support a single null key? Secondly, is there an existing dictionary-like collection that does? I want to store an "empty" or "missing" or "default" System.Type, thought null would work well for this. More specifically, I've written this class: class Switch { private Dictionary<Type, Action<object>> _dict; public Switch(params KeyValuePair<Type, Action<object>>[] cases) { _dict = new Dictionary<Type, Action<object>>(cases.Length); foreach (var entry in cases) _dict.Add(entry.Key, entry.Value); } public void Execute(object obj) { var type = obj.GetType(); if (_dict.ContainsKey(type)) _dict[type](obj); } public static void Execute(object obj, params KeyValuePair<Type, Action<object>>[] cases) { var type = obj.GetType(); foreach (var entry in cases) { if (entry.Key == null || type.IsAssignableFrom(entry.Key)) { entry.Value(obj); break; } } } public static KeyValuePair<Type, Action<object>> Case<T>(Action action) { return new KeyValuePair<Type, Action<object>>(typeof(T), x => action()); } public static KeyValuePair<Type, Action<object>> Case<T>(Action<T> action) { return new KeyValuePair<Type, Action<object>>(typeof(T), x => action((T)x)); } public static KeyValuePair<Type, Action<object>> Default(Action action) { return new KeyValuePair<Type, Action<object>>(null, x => action()); } } For switching on types. There are two ways to use it: Statically. Just call Switch.Execute(yourObject, Switch.Case<YourType>(x => x.Action())) Precompiled. Create a switch, and then use it later with switchInstance.Execute(yourObject) Works great except when you try to add a default case to the "precompiled" version (null argument exception).

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  • BitmapFactory.decodeStream returning null when options are set.

    - by Robert Foss
    Hi! I'm having issues with BitmapFactory.decodeStream(). When using it without options, it will return an image. But when I use it with options as in .decodeStream(inputStream, null, options) it never returns Bitmaps. What I'm trying to do is to downsample a Bitmap before I actually load it to save memory. I've read some good guides, but none using .decodeStream. Here httpIM:NOT//nornalbion.SPAMcom/blog/?p=143 httpIM:NOT//kfb-android.blogspot.SPAMcom/2009/04/image-processing-in-android.html WORKS JUST FINE InputStream is = connection.getInputStream(); Bitmap img = BitmapFactory.decodeStream(is, null, options); DOESNT WORK InputStream is = connection.getInputStream(); Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeStream(is, null, options); Boolean scaleByHeight = Math.abs(options.outHeight - TARGET_HEIGHT) >= Math.abs(options.outWidth - TARGET_WIDTH); if(options.outHeight * options.outWidth * 2 >= 200*100*2){ // Load, scaling to smallest power of 2 that'll get it <= desired dimensions double sampleSize = scaleByHeight ? options.outHeight / TARGET_HEIGHT : options.outWidth / TARGET_WIDTH; options.inSampleSize = (int)Math.pow(2d, Math.floor( Math.log(sampleSize)/Math.log(2d))); System.out.println("Samplesize: " + options.inSampleSize); } // Do the actual decoding options.inJustDecodeBounds = false; //options.inTempStorage = new byte[IMG_BUFFER_LEN]; Bitmap img = BitmapFactory.decodeStream(is, null, options);

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  • Why is document.body == null in Firefox but not Safari

    - by dlamblin
    I have a problem with a page where I am trying to get colorbox (a kind of lightbox for jQuery) working. It doesn't work apparently due to the document.body being null in FireFox (3.5.3). This is not the case in Safari (4.0.3) where the colorbox works. Something that jumps out at me is that (I'm using Drupal 6) drupal has appended a script tag to set some JavaScript variables at the very bottom of the page, below the closing body and html tags. Otherwise I don't see a problem. Unfortunately I'm having a lot of trouble getting it not to do that. Could it be this that's causing FF to have issues with the body? Using colorbox's example files in Firefox does work (and the document.body is defined there). Is there any way I could use jQuery to refill the document.body property with something from $() perhaps, or should I keep banging at drupal to not put a script tag outside the html tags (easier said than done)? To clarify the document.body is null even after the page is done loading. Here's a Firebug console capture: >>> document.body null >>> $().attr('body') null

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  • Selenium RC throws sessionsid should not be null exception with assertTextPresent, phpunit 3.4 bug o

    - by user342775
    I am looking to migrate my selenium RC tests to using PHPUnit 3.4.12 from PHPUnit 3.3.2 The selenium test will fail with an exception of the following when I use assertTextPresent() PHPUnit_Framework_Exception: Response from Selenium RC server for getLocation(). ERROR Server Exception: sessionId should not be null; has this session been started yet?. For example: public function testSending($browser) { ... $browser->click("send"); $browser->waitForPageToLoad("30000"); $browser->assertTextPresent("text"); } Below is the selenium RC log (running on Windows): 15:40:19.676 INFO - Command request: isTextPresent[text, ] on session 153d03a123c42098711994f43c2db34 15:40:19.691 INFO - Got result: OK,false on session 153d023a123c42098711994f43cdb34 15:40:19.879 INFO - Command request: testComplete[, ] on session 153d023a123c4298711994f43c2db34 15:40:19.879 INFO - Killing Firefox... 15:40:20.269 INFO - Got result: OK on session 153d023a123c42098711994f43c2db34 15:40:20.472 INFO - Command request: getLocation[, ] on session null 15:40:20.472 ERROR - Exception running 'getLocation 'command on session null java.lang.NullPointerException: sessionId should not be null; has this session been started yet? As you can see, the test should have completed as indicated by the "Killing Firefox" bit, but it instead continued to do something else and triggered the getLocation[, ] command which caused the exception. I have tried the same test with PHPUnit 3.3.2 which did not produce this problem - the test would happily end without the getLocation(). Any ideas? thanks

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  • Ldap query returns null result when deployed.

    - by Trey Carroll
    I'm using a very simple Ldap query in my asp.net mvc 2.0 site: String ldapPath = ConfigReader.LdapPath; String emailAddress = null; try { DirectorySearcher search = new DirectorySearcher(ConfigReader.LdapPath); search.Filter = String.Format("(&(objectClass=user)(objectCategory=person)(objectSid={0})) ", securityIdentifierValue); // add the mail property to the list of props to retrieve search.PropertiesToLoad.Add("mail"); var result = search.FindOne(); if (result == null) { throw new Exception("Ldap Query with filter:" + search.Filter.ToString() + " returned a null value (no match found)"); } else { emailAddress = result.Properties["mail"][0].ToString(); } } catch (ArgumentOutOfRangeException aoorEx) { throw new Exception( "The query could not find an email for this user."); } catch (Exception ex) { //_log.Error(string.Format("======!!!!!! ERROR ERROR ERROR !!!!! in LdapLookupUtil.cs getEmailFromLdap Exception: {0}", ex)); throw ex; } return emailAddress; It works fine on my localhost machine. It works fine when I run it in VS2010 on the server. It always returns a null result when deployed. Here is my web.config: Asp.Net Configuration option in Visual Studio. A full list of settings and comments can be found in machine.config.comments usually located in \Windows\Microsoft.Net\Framework\v2.x\Config -- section enables configuration of the security authentication mode used by ASP.NET to identify an incoming user. -- <!-- -- section enables configuration of what to do if/when an unhandled error occurs during the execution of a request. Specifically, it enables developers to configure html error pages to be displayed in place of a error stack trace. -- I'm running it under the default app pool. Does anybody see the problem? This is driving me crazy!

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  • How to correct my null exception??

    - by kostas
    hi!i have created a contact form using c# and web services.i would like to get an alert message if the user hasnt filled his name or when his name is a number.this is my c# code: public partial class Default2 : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { Validation.WebService validate = new Validation.WebService(); bool ismail = validate.isEmail(TextBox2.Text); if (!ismail) { Label1.Text = "your mail is wrong!!"; } Validation.nameVal valid = new Validation.nameVal(); bool isname = valid.isName(TextBox1.Text); if (!isname ) { Label2.Text = "Your name is wrong!!"; } else if (isname==null) { Label2.Text = "Please fill in your name"; } if (isname && ismail) { { Label1.Text = null; Label2.Text = null; Label3.Text = "Your message has been send!";} } } } with this code i have a null exception..

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  • Does JAXWS client make difference between an empty collection and a null collection value as returne

    - by snowflake
    Since JAX-WS rely on JAXB, and since I observed the code that unpack the XML bean in JAX-B Reference Implementation, I guess the difference is not made and that a JAXWS client always return an empty collection, even the webservice result was a null element: public T startPacking(BeanT bean, Accessor<BeanT, T> acc) throws AccessorException { T collection = acc.get(bean); if(collection==null) { collection = ClassFactory.create(implClass); if(!acc.isAdapted()) acc.set(bean,collection); } collection.clear(); return collection; } I agree that for best interoperability service contracts should be non ambiguous and avoid such differences, but it seems that the JAX-WS service I'm invoking (hosted on a Jboss server with Jbossws implementation) is returning as expected either null either empty collection (tested with SoapUI). I used for my test code generated by wsimport. Return element is defined as: @XmlElement(name = "return", nillable = true) protected List<String> _return; I even tested to change the Response class getReturn method from : public List<String> getReturn() { if (_return == null) { _return = new ArrayList<String>(); } return this._return; } to public List<String> getReturn() { return this._return; } but without success. Any helpful information/comment regarding this problem is welcome !

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  • MySQL Stored Procedure Parameters are NULL

    - by emmilely
    I am stumped, and was hoping someone here would have a quick and easy answer. I did a fresh install of MySQL 5.5 and am trying to pass parameters into a stored procedure. The parameter values aren't being read by the stored procedure. MySQL doesn't throw an error and processes the code with null parameters. Here is the code: DELIMITER $$ CREATE DEFINER=`root`@`%` PROCEDURE `testing`(IN parameter INTEGER) BEGIN UPDATE table_name SET valueToChange = 'Test' WHERE mainID = @parameter; END And here is the query I'm using to call it: USE database_name; CALL testing(72); Can anyone help?

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  • Android - Dealing with a Dialog on Screen Orientation change

    - by Donal Rafferty
    I am overriding the onCreateDialog and onPrepareDialog methods or the Dialog class. I have followed the example from Reto Meier's Professional Android Application Development book, Chapter 5 to pull some XML data and then use a dialog to display the info. I have basically followed it exactly but changed the variables to suit my own XML schema as follows: @Override public Dialog onCreateDialog(int id) { switch(id) { case (SETTINGS_DIALOG) : LayoutInflater li = LayoutInflater.from(this); View settingsDetailsView = li.inflate(R.layout.details, null); AlertDialog.Builder settingsDialog = new AlertDialog.Builder(this); settingsDialog.setTitle("Provisioned Settings"); settingsDialog.setView(settingsDetailsView); return settingsDialog.create(); } return null; } @Override public void onPrepareDialog(int id, Dialog dialog) { switch(id) { case (SETTINGS_DIALOG) : String afpunText = " "; if(setting.getAddForPublicUserNames() == 1){ afpunText = "Yes"; } else{ afpunText = "No"; } String Text = "Login Settings: " + "\n" + "Password: " + setting.getPassword() + "\n" + "Server: " + setting.getServerAddress() + "\n"; AlertDialog settingsDialog = (AlertDialog)dialog; settingsDialog.setTitle(setting.getUserName()); tv = (TextView)settingsDialog.findViewById(R.id.detailsTextView); if (tv != null) tv.setText(Text); break; } } It works fine until I try changing the screen orientation, When I do this onPrepareDialog gets call but I get null pointer exceptions on all my variables. The error still occurs even when I tell my activity to ignore screen orientation in the manifest. So I presume something has been left out of the example in the book do I need to override another method to save my variables in or something?

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  • Server 2003 - Default installation of SharePoint throws javascript error 'undefined' is null or not an object

    - by Chris
    I have been handed a server that has a fresh installation of small business server 2003. SharePoint has been installed, and it is a completely fresh copy (no changes made) I know for a fact that everything was paid for so this isn't some dodgy copy. When I try to click any option in any of the floating menu's in IE 8, the browser asks me if I want to debug .. Error: 'undefined' is null or not an object for example, I got to Projects - and click on the sample project, then click delete on the floating menu that pops up and the error appears. This is brand new, I cannot believe I am having this problem! Has anyone come across this, is it an old problem with easy fix? All windows updates installed - see no updates for sharepoint? EDIT: This is WSS2 so I am going to upgrade to WSS3... http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=14117 http://www.techrepublic.com/article/installing-windows-sharepoint-services-30-on-windows-server-2003/6176833 Hopefully this will resolve the problem

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  • A RenderTargetView cannot be created from a NULL Resource

    - by numerical25
    I am trying to create my render target view but I get this error from direct X A RenderTargetView cannot be created from a NULL Resource To my knowledge it seems that I must fill the rendertarget pointer with data before passing it. But I am having trouble figure out how. Below is my declaration and implementation declaration #pragma once #include "stdafx.h" #include "resource.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #define MAX_LOADSTRING 100 class RenderEngine { protected: RECT m_screenRect; //direct3d Members ID3D10Device *m_pDevice; // The IDirect3DDevice10 // interface ID3D10Texture2D *m_pBackBuffer; // Pointer to the back buffer ID3D10RenderTargetView *m_pRenderTargetView; // Pointer to render target view IDXGISwapChain *m_pSwapChain; // Pointer to the swap chain RECT m_rcScreenRect; // The dimensions of the screen ID3DX10Font *m_pFont; // The font used for rendering text // Sprites used to hold font characters ID3DX10Sprite *m_pFontSprite; ATOM RegisterEngineClass(); void Present(); public: static HINSTANCE m_hInst; HWND m_hWnd; int m_nCmdShow; TCHAR m_szTitle[MAX_LOADSTRING]; // The title bar text TCHAR m_szWindowClass[MAX_LOADSTRING]; // the main window class name void DrawTextString(int x, int y, D3DXCOLOR color, const TCHAR *strOutput); //static functions static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam); static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam); bool InitWindow(); bool InitDirectX(); bool InitInstance(); int Run(); RenderEngine() { m_screenRect.right = 800; m_screenRect.bottom = 600; } }; my implementation bool RenderEngine::InitDirectX() { //potential error. You did not set to zero memory and you did not set the scaling property DXGI_MODE_DESC bd; bd.Width = m_screenRect.right; bd.Height = m_screenRect.bottom; bd.Format = DXGI_FORMAT_R8G8B8A8_UNORM; bd.RefreshRate.Numerator = 60; bd.RefreshRate.Denominator = 1; DXGI_SAMPLE_DESC sd; sd.Count = 1; sd.Quality = 0; DXGI_SWAP_CHAIN_DESC swapDesc; ZeroMemory(&swapDesc, sizeof(swapDesc)); swapDesc.BufferDesc = bd; swapDesc.SampleDesc = sd; swapDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; swapDesc.OutputWindow = m_hWnd; swapDesc.BufferCount = 1; swapDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD, swapDesc.Windowed = true; swapDesc.Flags = 0; HRESULT hr; hr = D3D10CreateDeviceAndSwapChain(NULL, D3D10_DRIVER_TYPE_HARDWARE, NULL, D3D10_CREATE_DEVICE_DEBUG, D3D10_SDK_VERSION , &swapDesc, &m_pSwapChain, &m_pDevice); if(FAILED(hr)) return false; // Create a render target view hr = m_pDevice->CreateRenderTargetView( m_pBackBuffer, NULL, &m_pRenderTargetView); // FAILS RIGHT HERE // if(FAILED(hr)) return false; return true; }

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  • Redirect output of Python program to /dev/null

    - by STM
    I have a Python executable, written and compiled by somebody else, that I simply need to run once halfway down my own bash script. The program uses a text-based UI, therefore waits for input before proceeding, but the key operations it performs when starting are required in my bash script. A messy (and strange) procedure I know, but unfortunately I haven't got any other options. I've gotten around forcefully closing the program with a kill signal, but the program's TUI insists on outputting to wherever it's run. I've tried redirecting both stdout and stderr to /dev/null and running the program in the background by suffixing an ampersand, but simply can't get it to play ball. I believe the cause is the program spawns other processes, and the output redirection of the parent process doesn't affect them. Is there any trick I can utilise to redirect all output from child processes too?

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  • Intent Bundle returns Null every time?

    - by Max
    I have some extras sent to a new intent. There it grabs the bundle and tests if it is null. Every single time it is null even though I am able to get the values passed and use them. Can anyone see what is wrong with the if statement? Intent i = getIntent(); Bundle b = i.getExtras(); int picked = b.getInt("PICK"); int correct = b.getInt("CORR"); type = b.getString("RAND"); if(b == null || !b.containsKey("WELL")) { Log.v("BUNDLE", "bun is null"); } else { Log.v("BUNDLE", "Got bun well"); } EDIT: Heres where the bundle is created. Intent intent = new Intent(this, app.pack.son.class); Bundle b = new Bundle(); b.putInt("PICK", pick); b.putInt("CORR", corr); b.putString("RAND", "yes"); intent.putExtras(b); startActivity(intent);

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  • Avoiding null point exception in el in JSF

    - by Buddhika Ariyaratne
    I am developing a JSF application with JPA(EclipseLink 2.0) and Primefaces. I want to know is there any way to avoid null point exception when el calls a property of a null object. I have described the situation. I have Bill class. There may be no or more BillItem objects with a Bill objects. Each BillItem object have Objects like Make, Country, Manufacturer, etc objects. I am displaying several properties of a bill within a single JSF file like this. "#{billControlled.bill.billItem.modal.name}" But if a bill is not selected, or when there are no bill items for a selected bill, the properties accessing in the el are null. I can avoid this by creating new objects for every bill, for example, new make for a new bill item, etc or by creating new properties in the controller itself for all the properties. But that is a very long way and feel like rudimentory. Is there any good practice to avoid this null point exception in el in JSF?

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  • Pointer problem in C for char*

    - by egebilmuh
    Hi guys, i use pointer for holding name and research lab property. But when i print the existing Vertex ,when i print the vertex, i cant see so -called attributes properly. For example though real value of name is "lancelot" , i see it as wrong such as "asdasdasdasd" struct vertex { int value; char*name; char* researchLab; struct vertex *next; struct edge *list; }; void GRAPHinsertV(Graph G, int value,char*name,char*researchLab) { //create new Vertex. Vertex newV = malloc(sizeof newV); // set value of new variable to which belongs the person. newV->value = value; newV->name=name; newV->researchLab=researchLab; newV->next = G->head; newV->list = NULL; G->head = newV; G->V++; } /*** The method creates new person. **/ void createNewPerson(Graph G) { int id; char name[30]; char researchLab[30]; // get requeired variables. printf("Enter id of the person to be added.\n"); scanf("%d",&id); printf("Enter name of the person to be added.\n"); scanf("%s",name); printf("Enter researc lab of the person to be added\n"); scanf("%s",researchLab); // insert the people to the social network. GRAPHinsertV(G,id,name,researchLab); } void ListAllPeople(Graph G) { Vertex tmp; Edge list; for(tmp = G->head;tmp!=NULL;tmp=tmp->next) { fprintf(stdout,"V:%d\t%s\t%s\n",tmp->value,tmp->name,tmp->researchLab); } system("pause"); }

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  • warning: assignment makes pointer from integer without a cast

    - by FILIaS
    Im new in programming c with arrays and files. Im just trying to run the following code but i get warnings like that: warning: assignment makes pointer from integer without a cast Any help? It might be silly... but I cant find what's wrong. FILE *fp; FILE *cw; char filename_game[40],filename_words[40]; int main() { while(1) { /* Input filenames. */ printf("\n Enter the name of the file with the cryptwords array: \n"); gets(filename_game); printf("\n Give the name of the file with crypted words:\n"); gets(filename_words); /* Try to open the file with the game */ if (fp=fopen("crypt.txt","r")!=NULL) { printf("\n Successful opening %s \n",filename_game); fclose(fp); puts("\n Enter x to exit,any other to continue! \n "); if ( (getc(stdin))=='x') break; else continue; } else { fprintf(stderr,"ERROR!%s \n",filename_game); puts("\n Enter x to exit,any other to continue! \n"); if (getc(stdin)=='x') break; else continue; } /* Try to open the file with the names. */ if (cw=fopen("words.txt","r")!=NULL) { printf("\n Successful opening %s \n",filename_words); fclose(cw); puts("\n Enter x to exit,any other to continue \n "); if ( (getc(stdin))=='x') break; else continue; } else { fprintf(stderr,"ERROR!%s \n",filename_words); puts("\n Enter x to exit,any other to continue! \n"); if (getc(stdin)=='x') break; else continue; } } return 0; }

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  • MySQL DDL error creating tables

    - by Alexandstein
    I am attempting to create tables for a MySQL database, but I am having some syntactical issues. It would seem that syntax checking is behaving differently between tables for some reason. While I've gotten all the other tables to go through, the table, 'stock' doesn't seem to be working, despite seeming to use the same syntax patterns. CREATE TABLE users ( user_id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, username VARCHAR(30) NOT NULL, password CHAR(41) NOT NULL, date_joined DATETIME NOT NULL, funds DOUBLE UNSIGNED NOT NULL, PRIMARY KEY(user_id), UNIQUE KEY(username) ); CREATE TABLE owned_stocks ( id SMALLINT UNSIGNED NOT NULL AUTO_INCREMENT, user_id SMALLINT UNSIGNED NOT NULL, paid_price DOUBLE UNSIGNED NOT NULL, quantity MEDIUMINT UNSIGNED NOT NULL, purchase_date DATETIME NOT NULL, PRIMARY KEY(id) ); CREATE TABLE tracking_stocks ( ticker VARCHAR(5) NOT NULL, user_id SMALLINT UNSIGNED NOT NULL, PRIMARY KEY(ticker) ); CREATE TABLE stocks ( ticker VARCHAR(5) NOT NULL, last DOUBLE UNSIGNED NOT NULL, high DOUBLE UNSIGNED NOT NULL, low DOUBLE UNSIGNED NOT NULL, company_name VARCHAR(30) NOT NULL, last_updated INT UNSIGNED NOT NULL, change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, PRIMARY KEY(ticker) ); Am I just missing a really obvious syntactical issue? ERROR: #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'change DOUBLE NOT NULL, percent_change DOUBLE NOT NULL, last DOUBLE' at line 4

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  • C++ return a "NULL" object if search result not found

    - by aduric
    I'm pretty new to C++ so I tend to design with a lot of Java-isms while I'm learning. Anyway, in Java, if I had class with a 'search' method that would return an object T from a Collection< T that matched a specific parameter, I would return that object and if the object was not found in the collection, I would return a NULL. Then in my calling function I would just check if(T != NULL) { ... } In C++, I'm finding out that I can't return a NULL if the object doesn't exist. I just want to return an 'indicator' of type T that notifies the calling function that no object has been found. I don't want to throw an exception because it's not really an exceptional circumstance. class Node { .... Attr& getAttribute(const string& attribute_name) const { //search collection //if found at i return attributes[i]; //if not found return NULL; } private: vector<Attr> attributes; }

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  • OS X Automator empty, blank or null value.

    - by Brian
    I have some data files mostly excel, word and pdf files most of the files have no extension on them. So they are missing the .doc .xls. This data needs to be used in a Windows environment now. I have created automator apps for each of the file types I want to add the ext onto. The problem is it also adds the extension to files that already have an extension. So data.xls becomes data.xls.xls I would like to figure a way to only add the extenion to the files without extension. How do I tell the finder filter that i only want it to return files without extensions. I see how to add a line to filter by extension but I don't know how to let it know I want only blank or null or files without any extensions. Thanks

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  • .save puts NULL in id field in Rails

    - by mathee
    Here's the model file: class ProfileTag < ActiveRecord::Base def self.create_or_update(options = {}) id = options.delete(:id) record = find_by_id(id) || new record.id = id record.attributes = options puts "record.profile_id is" puts record.profile_id record.save! record end end This gives me the correct print out in my log. But it also says that there's a call to UPDATE that sets profile_id to NULL. Here's some of the output in the log file: Processing ProfilesController#update (for 127.0.0.1 at 2010-05-28 18:20:54) [PUT] Parameter: {"commit"=>"Save", ...} ?[4;36;1mProfileTag Create (0.0ms)?[0m ?[0;1mINSERT INTO `profile_tags` (`reputation_value`, `updated_at`, `tag_id`, `id`, `profile_id`, `created_at`) VALUES(0, '2010-05-29 01:20:54', 1, NULL, 4, '2010-05-29 01:20:54')?[0m ?[4;35;1mSQL (2.0ms)?[0m ?[0mCOMMIT?[0m ?[4;36;1mSQL (0.0ms)?[0m ?[0;1mBEGIN?[0m ?[4;35;1mSQL (0.0ms)?[0m ?[0mCOMMIT?[0m ?[4;36;1mProfileTag Load (0.0ms)?[0m ?[0;1mSELECT * FROM `profile_tags` WHERE (`profile_tags`.profile_id = 4) ?[0m ?[4;35;1mSQL (1.0ms)?[0m ?[0mBEGIN?[0m ?[4;36;1mProfileTag Update (0.0ms)?[0m ?[0;1mUPDATE `profile_tags` SET profile_id = NULL WHERE (profile_id = 4 AND id IN (35)) ?[0m I'm not sure I understand why the INSERT puts the value into profile_id properly, but then it sets it to NULL on an UPDATE. If you need more specifics, please let me know. I'm thinking that the save functionality does many things other than INSERTs into the database, but I don't know what I need to specify so that it will properly set profile_id.

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  • C++ Pointer member function with templates assignment with a member function of another class

    - by Agusti
    Hi, I have this class: class IShaderParam{ public: std::string name_value; }; template<class TParam> class TShaderParam:public IShaderParam{ public: void (TShaderParam::*send_to_shader)( const TParam&,const std::string&); TShaderParam():send_to_shader(NULL){} TParam value; void up_to_shader(); }; typedef TShaderParam<float> FloatShaderParam; typedef TShaderParam<D3DXVECTOR3> Vec3ShaderParam; In another class, I have a vector of IShaderParams* and functions that i want to send to "send_to_shader". I'm trying assign the reference of these functions like this: Vec3ShaderParam *_param = new Vec3ShaderParam; _param-send_to_shader = &TShader::setVector3; This is the function: void TShader::setVector3(const D3DXVECTOR3 &vec, const std::string &name){ //... } And this is the class with IshaderParams*: class TShader{ std::vector params; public: Shader effect; std::string technique_name; TShader(std::string& afilename):effect(NULL){}; ~TShader(); void setVector3(const D3DXVECTOR3 &vec, const std::string &name); When I compile the project with Visual Studio C++ Express 2008 I recieve this error: Error 2 error C2440: '=' :can't make the conversion 'void (__thiscall TShader::* )(const D3DXVECTOR3 &,const std::string &)' a 'void (__thiscall TShaderParam::* )(const TParam &,const std::string &)' c:\users\isagoras\documents\mcv\afoc\shader.cpp 127 Can I do the assignment? No? I don't know how :-S Yes, I know that I can achieve the same objective with other techniques, but I want to know how can I do this..

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