Search Results

Search found 18475 results on 739 pages for 'non exist'.

Page 415/739 | < Previous Page | 411 412 413 414 415 416 417 418 419 420 421 422  | Next Page >

  • Regular expressions in findstr

    - by Johannes Rössel
    I'm doing a little string validation with findstr and its /r flag to allow for regular expressions. In particular I'd like to validate integers. The regex ^[0-9][0-9]*$ worked fine for non-negative numbers but since I now support negative numbers as well I tried ^([1-9][0-9]*|0|-[1-9][0-9]*)$ for either positive or negative integers or zero. The regex works fine theoretically. I tested it in PowerShell and it matches what I want. However, with findstr /r /c:"^([1-9][0-9]*|0|-[1-9][0-9]*)$" it doesn't. While I know that findstr doesn't have the most advanced regex support (even below Notepad++ which is probably quite an achievement), I would have expected such simple expressions to work. Any ideas what I'm doing wrong here?

    Read the article

  • Using nullable types in C#

    - by Martin Brown
    I'm just interested in people's opinions. When using nullable types in C# what is the best practice way to test for null: bool isNull = (i == null); or bool isNull = !i.HasValue; Also when assigning to a non-null type is this: long? i = 1; long j = (long)i; better than: long? i = 1; long j = i.Value;

    Read the article

  • MS SQL Bridge Table Constraints

    - by greg
    Greetings - I have a table of Articles and a table of Categories. An Article can be used in many Categories, so I have created a table of ArticleCategories like this: BridgeID int (PK) ArticleID int CategoryID int Now, I want to create constraints/relationships such that the ArticleID-CategoryID combinations are unique AND that the IDs must exist in the respective primary key tables (Articles and Categories). I have tried using both VS2008 Server Explorer and Enterprise Manager (SQL-2005) to create the FK relationships, but the results always prevent Duplicate ArticleIDs in the bridge table, even though the CategoryID is different. I am pretty sure I am doing something obviously wrong, but I appear to have a mental block at this point. Can anyone tell me please how should this be done? Greaty appreciated!

    Read the article

  • Classes / instances in Ontology

    - by SODA
    Hi, I'm trying to comprehend ontology basics. Here's an example: car (class) 2009 VW CC (sub-class or instance?) My neighbor's 2009 VW CC (instance) My issue is understanding what is "2009 VW CC" (as a car model). If you're making product model a sub-class in the ontology - all of a sudden your ontology becomes bloated with thousands of subclasses of a "car". That's redundant. At the same time we can't say "2009 VW CC" is an instance, at least it's not material instance of a class. Does it make sense to distinguish between regular instances and material (distinct physical objects)? At the other hand, if both are instances (of different nature so to say), then how can instance inherit properties / relations of a non-class?

    Read the article

  • ASP.NET MVC 2 RC2 Model Binding with NVARCHAR NOT NULL column

    - by Gary McGill
    I have a database column defined as NVARCHAR(1000) NOT NULL DEFAULT(N'') - in other words, a non-nullable text column with a default value of blank. I have a model class generated by the Linq-to-SQL Classes designer, which correctly identifies the property as not nullable. I have a TextAreaFor in my view for that property. I'm using UpdateModel in my controller to fetch the value from the form and populate the model object. If I view the web page and leave the text area blank, UpdateModel insists on setting the property to NULL instead of empty string. (Even if I set the value to blank in code prior to calling UpdateModel, it still overwrites that with NULL). Which, of course, causes the subsequent database update to fail. I could check all such properties for NULL after calling UpdateModel, but that seems ridiculous - surely there must be a better way? Please don't tell me I need a custom model binder for such a simple scenario...!

    Read the article

  • How to reflect in the database a new belongs_to and has_many relationship in Ruby on Rails

    - by Ken I.
    I am new to rails (usually a python guy) and have just been trying to build a simple task manager application for fun. I am using Devise for authentication and have a single Task object I am trying to relate to a user. I have added the following to the Task model: class Task < ActiveRecord::Base belongs_to :user end and I have added the following in my User model for Devise: class User < ActiveRecord::Base has_many :dreams <<normal Devise stuff>> end Whenever I added this information I then ran: rake db:migrate. It then gave me an error that the database field did not exist for user_id when I tried to do anything with it. I am sure it is something rather simple that I am missing. Thanks for the help.

    Read the article

  • Test Column exists, Add Column, and Update Column

    - by david.clarke
    I'm trying to write a SQL Server database update script. I want to test for the existence of a column in a table, then if it doesn't exist add the column with a default value, and finally update that column based on the current value of a different column in the same table. I want this script to be runnable multiple times, the first time updating the table and on subsequent runs the script should be ignored. My script currently looks like the following: IF NOT EXISTS(SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'PurchaseOrder' AND COLUMN_NAME = 'IsDownloadable') BEGIN ALTER TABLE [dbo].[PurchaseOrder] ADD [IsDownloadable] bit NOT NULL DEFAULT 0 UPDATE [dbo].[PurchaseOrder] SET [IsDownloadable] = 1 WHERE [Ref] IS NOT NULL END SQL Server returns error "Invalid column name 'IsDownloadable'", i.e. I need to commit the DDL before I can update the column. I've tried various permutations but I'm getting nowhere fast.

    Read the article

  • How to create generic class which takes 3 types.

    - by scope-creep
    I'm trying to make a generic class that takes 3 types, either a simple string, IList or a IList. public class OntologyStore { } public sealed class jim<T> where T:new() { IList<string> X = null; IList<OntologyStore> X1 = null; public bob() { if (typeof(T) == typeof(String)) { X = new List<string>(); } if (typeof(T) == typeof(OntologyStore)) { X1 = new List<OntologyStore>(); } } } I can easily create, which you would expect to work, jim<OntologyStore> x1=new jim<jim<OntologyStore>() as you would expect, but when I put in jim<string> x2=new jim<string>() the compiler reports the string is non abtract type, which you would expect. Is it possible to create a generic class, which can instantiate as a class which holds string, or a IList or an IList?

    Read the article

  • iPhone: How to detect if an EKEvent instance can be modified?

    - by Tom van Zummeren
    While working with the EventKit on iPhone I noticed that some events can exist which cannot be modified. Examples I encountered so far are birthdays and events synced with CalDAV. When you view the event's details in the standard built-in calendar app on iPhone the "Edit" button in the top-right corner is not visible in these cases, where it would be visible when viewing "normal" events. I've searched everywhere, read all documentation there is but I simply can't find anything that tells me how to detect this behavior! I can only detect it afterwards: edit an event's title save it to the event store check the event's title, if it has not changed it is not editable! I am looking for a way that I can detect the non-editable behavior of an event beforehand. I know this is possible because I've seen other calendar apps implement this correctly.

    Read the article

  • Python - Check if numbers in list are factors of a number

    - by Zach
    Hey, I have a list of numbers (integers) (say, from 1 to 10). They're not necessarily consecutive, but they are in ascending order. I've prompted the user multiple times to enter a choice of the available numbers. When that number is entered, it is removed from the list along with any of its factors that may be there. I've prevented the user from selecting prime numbers. However, at some point in time, there may be non-prime numbers there, which have no factors remaining. I'm relatively new to Python, so I'm having trouble implementing: Checking if the number selected has no factors remaining (even if it is not prime). Checking if only prime numbers remain, or numbers without factors. I'm thinking of using for statements, but I'm not sure exactly how to implement them. Can anyone offer advice, or code? Thanks in advance... PS. In case anyone's wondering, I'm doing an implementation of the game of Taxman in Python.

    Read the article

  • django-admin formfield_for_* change default value per/depending on instance

    - by Nick Ma.
    Hi, I'm trying to change the default value of a foreignkey-formfield to set a Value of an other model depending on the logged in user. But I'm racking my brain on it... This: Changing ForeignKey’s defaults in admin site would an option to change the empty_label, but I need the default_value. #Now I tried the following without errors but it didn't had the desired effect: class EmployeeAdmin(admin.ModelAdmin): ... def formfield_for_foreignkey(self, db_field, request=None, **kwargs): formfields= super(EmployeeAdmin, self).formfield_for_foreignkey(db_field, request, **kwargs) if request.user.is_superuser: return formfields if db_field.name == "company": #This is the RELEVANT LINE kwargs["initial"] = request.user.default_company return db_field.formfield(**kwargs) admin.site.register(Employee, EmployeeAdmin) ################################################################## # REMAINING Setups if someone would like to know it but i think # irrelevant concerning the problem ################################################################## from django.contrib.auth.models import User, UserManager class CompanyUser(User): ... objects = UserManager() company = models.ManyToManyField(Company) default_company= models.ForeignKey(Company, related_name='default_company') #I registered the CompanyUser instead of the standard User, # thats all up and working ... class Employee(models.Model): company = models.ForeignKey(Company) ... Hint: kwargs["default"] ... doesn't exist. Thanks in advance, Nick

    Read the article

  • Bug tracking/ticket systems? What is good?

    - by Earlz
    Hello, we are looking for a bug tracking software that is suitable for us developers and for our (non technical) end users. We our currently using FogBugz which is very amazing, except for it sucks for the end user support. It could be possible to write a portal/add in for it to do what we want, but it'd still be rather hackish to make FogBugz do something it wasn't designed for. What bug tracking systems out there would you guys recommend? We are looking for something relatively cheap(or free). We are a very small startup (less than 5 people) dealing with 50 or so end users. Any ideas? Also, we do not need extra features like wikis or discussion groups or anything like that. Basically just a way for our end users to submit bugs and support requests, and a way for the developers to keep track of bugs and features.

    Read the article

  • Windows7 IIS7: zips don't have php5isapi.dll Can I use php.dll instead?

    - by Pete Alvin
    The page: How to Install PHP 5.2 on IIS 7and Windows Vista (and a few others) reference a mysterious php5isapi.dll which is not in the Windows install, or the zip files: php-5.3.2-Win32-VC9-x86.zip - VC9 x86 Thread Safe php-5.3.2-nts-Win32-VC9-x86.zip - VC9 x86 Non Thread Safe There was another post on stackoverflow that said it's obsolete and replaced by "fastapi" but no instructions mention this. I did find a php.dll in the zip file. Can I use that instead of php5isapi.dll? It's very frustrating trying to install basic PHP5 on Windows with MySQL.

    Read the article

  • .NET: IOException for permissions when creating new file?

    - by Rosarch
    I am trying to create a new file and write XML to it: FileStream output = File.Create(Path.Combine(PATH_TO_DATA_DIR, fileName)); The argument evaluates to: C:\path\to\Data\test.xml The exception is: The process cannot access the file 'C:\path\to\Data\test.xml' because it is being used by another process. What am I doing wrong here? UPDATE: This code throws the same exception: StreamWriter writer = new StreamWriter(Path.Combine(PATH_TO_DATA_DIR, fileName)); UPDATE 2: The file I am trying to create does not exist in the file system. So how can be it in use?

    Read the article

  • Asp.Net MVC does automatic model validation for DateTime but no others

    - by MattSlay
    I'm using MVC 2 with some Models from a LinqToSql project that I built. I see that when I post back to a Controller Action after editing a form that has a DateTime field from the Model, the MVC Html.ValidationMessageFor() helper will nicely display an error beside the Date text box. This seems to happen automatically when the you test ModelState.IsValid() in the Controller Action, as if the MVC model binding automatically knows that the DateTime field cannot be empty. My question is... I have some other string fields in these LinqToSql generated classes that are Not-Nullable (marked as Not Nullable in Sql Server which passes thourgh to the LinqToSql generated classes), so why doesn't Mr. MVC pick up on those as well and display a "Required" message in the ValidationMessageFor() placeholders I have added for those fields? Sure, I have successfully added the MetadataType(typeof) buddy classes to cover these Non-nullable string fields, but it sure does seem redundant to add all this metadata in buddy classes when the LinqToSql generated classes already contain enough info that MVC could sniff out. It MVC validation works with DateTime automatically, why not these Not-nullable fields too?

    Read the article

  • How to group a complex list of objects using LINQ?

    - by Daoming Yang
    I want to select and group the products, and rank them by the number of times they occur. For example, I have an OrderList each of order object has a OrderProductVariantList(OrderLineList), and each of OrderProductVariant object has ProductVariant, and then the ProductVariant object will have a Product object which contains product information. A friend helped me with the following code. It could be compiled, but it did not return any value/result. I used the watch window for the query and it gave me "The name 'query' does not exist in the current context". Can anyone help me? Many thanks. var query = orderList.SelectMany( o => o.OrderLineList ) // results in IEnumerable<OrderProductVariant> .Select( opv => opv.ProductVariant ) .Select( pv => p.Product ) .GroupBy( p => p ) .Select( g => new { Product = g.Key, Count = g.Count() });

    Read the article

  • Drupal Migration Problem

    - by Gok Demir
    After migrating my Drupal (6.16) installation from shared hosting to Linode VPS (Ubunto 10.04 32 bit). Whenever I click a URL it shows only the homepage. I put ?q=user at the end of the URL to login as an admin. When I logged in it is the same. I couldn't navigate to any URL. It shows only homepage. I forgot to clean Drupal cache before migration. Is it because of this? I couldn't navigate to Administer Site configuration Performance to clean cache, nothing works. By the way .htaccess Rewrite on enabled as shown below. apache2 apache2-doc apache2-utils libapache2-mod-php5 php5 php-pear php5-xcache php5-suhosin php5-mysql packages are installed. What can I do? # # Apache/PHP/Drupal settings: # # Protect files and directories from prying eyes. <FilesMatch "\.(engine|inc|info|install|make|module|profile|test|po|sh|.*sql|theme|tpl(\.php)?|xtmpl|svn-base)$|^(code-style\.pl|Entries.*|Repository|Root|Tag|Template|all-wcprops|entries|format)$"> Order allow,deny </FilesMatch> # Don't show directory listings for URLs which map to a directory. Options -Indexes # Follow symbolic links in this directory. Options +FollowSymLinks # Make Drupal handle any 404 errors. ErrorDocument 404 /index.php # Force simple error message for requests for non-existent favicon.ico. <Files favicon.ico> # There is no end quote below, for compatibility with Apache 1.3. ErrorDocument 404 "The requested file favicon.ico was not found. </Files> # Set the default handler. DirectoryIndex index.php # Override PHP settings. More in sites/default/settings.php # but the following cannot be changed at runtime. # PHP 4, Apache 1. <IfModule mod_php4.c> php_value magic_quotes_gpc 0 php_value register_globals 0 php_value session.auto_start 0 php_value mbstring.http_input pass php_value mbstring.http_output pass php_value mbstring.encoding_translation 0 </IfModule> # PHP 4, Apache 2. <IfModule sapi_apache2.c> php_value magic_quotes_gpc 0 php_value register_globals 0 php_value session.auto_start 0 php_value mbstring.http_input pass php_value mbstring.http_output pass php_value mbstring.encoding_translation 0 </IfModule> # PHP 5, Apache 1 and 2. <IfModule mod_php5.c> php_value magic_quotes_gpc 0 php_value register_globals 0 php_value session.auto_start 0 php_value mbstring.http_input pass php_value mbstring.http_output pass php_value mbstring.encoding_translation 0 </IfModule> # Requires mod_expires to be enabled. <IfModule mod_expires.c> # Enable expirations. ExpiresActive On # Cache all files for 2 weeks after access (A). ExpiresDefault A1209600 <FilesMatch \.php$> # Do not allow PHP scripts to be cached unless they explicitly send cache # headers themselves. Otherwise all scripts would have to overwrite the # headers set by mod_expires if they want another caching behavior. This may # fail if an error occurs early in the bootstrap process, and it may cause # problems if a non-Drupal PHP file is installed in a subdirectory. ExpiresActive Off </FilesMatch> </IfModule> # Various rewrite rules. <IfModule mod_rewrite.c> RewriteEngine on # If your site can be accessed both with and without the 'www.' prefix, you # can use one of the following settings to redirect users to your preferred # URL, either WITH or WITHOUT the 'www.' prefix. Choose ONLY one option: # # To redirect all users to access the site WITH the 'www.' prefix, # (http://example.com/... will be redirected to http://www.example.com/...) # adapt and uncomment the following: # RewriteCond %{HTTP_HOST} ^example\.com$ [NC] # RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301] # # To redirect all users to access the site WITHOUT the 'www.' prefix, # (http://www.example.com/... will be redirected to http://example.com/...) # uncomment and adapt the following: # RewriteCond %{HTTP_HOST} ^www\.example\.com$ [NC] # RewriteRule ^(.*)$ http://example.com/$1 [L,R=301] # Modify the RewriteBase if you are using Drupal in a subdirectory or in a # VirtualDocumentRoot and the rewrite rules are not working properly. # For example if your site is at http://example.com/drupal uncomment and # modify the following line: # RewriteBase /drupal # # If your site is running in a VirtualDocumentRoot at http://example.com/, # uncomment the following line: # RewriteBase / # Rewrite URLs of the form 'x' to the form 'index.php?q=x'. RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_URI} !=/favicon.ico RewriteRule ^(.*)$ index.php?q=$1 [L,QSA] </IfModule>

    Read the article

  • Adding a subview to UITableCellView

    - by hanno
    I want to add a subview to my UITableCellView subclass. However, non of the provided views in the class seem to be able to do exactly what I was looking for. I basically want to add my own background view, filling the whole cell. However, if I replace the backgroundView, the style from the grouped table view layout isn't displayed anymore. If I add a subview to backgroundView, the subview is not shown at all. If I add a subview to the contentView, I can't draw behind the accessory icon. What am I missing?

    Read the article

  • Recordset Paging works in IIS6 but not in IIIS7

    - by Spudhead
    Hi there, I've got a recordset/paging set up - works fine in IIS6 but when I run the site on an IIS7 server I get the following error: Microsoft OLE DB Provider for SQL Server error '80004005' [DBNETLIB][ConnectionOpen (Connect()).]SQL Server does not exist or access denied. /orders.asp, line 197 the code looks like this: Set objPagingConn = Server.CreateObject("ADODB.Connection") objPagingConn.Open CONN_STRING Set objPagingRS = Server.CreateObject("ADODB.Recordset") objPagingRS.PageSize = iPageSize objPagingRS.CacheSize = iPageSize objPagingRS.Open strSQL, objPagingConn, adOpenStatic, adLockReadOnly, adCmdText iPageCount = objPagingRS.PageCount iRecordCount = objPagingRS.RecordCount Line 197 is the objPagingConn,Open ... line. I've got about 10 sites like this to migrate - is there a simple fix in IIS7??? Help is greatly appreciated! Many thanks, Martin

    Read the article

  • Loading dynamic content and rewrite URL on Hashchange event with Jquery Mobile

    - by user3611500
    I'm building a mobile version for my website using Jquery Mobile API. The framework provides automate AJAX navigation processing. But as far as i know it require "real" pages for loading purpose. What i want to do is override the automate navigation process of it and process the hashchange on my own. But i can't not rewrite the url using window.hashChange, which is running well on my non-mobile website version : $(function () { $(window).off().hashchange(function () { if (location.hash.length > 1) { PageSelect(); } }); $(window).hashchange(); }); I just only want to take advantage on jquery mobile interfaces, i don't want anything with its automate ajax navigation stuff ! I tried to disable it using ajaxEnabled() but got no luck.

    Read the article

  • how to access facebook or twitter using blackberry API?

    - by Mishal
    Hi, I am newbie for such kind of social networking Application integration using blackberry API. i want to develope such kind of application which can use the facebook or twitter social networking site integration using available blackberry api. how to access the faceBook using blackberry API? Is there any webservice available of facebook on which blackberry api can work and access it? is there any application exist with whole source code for accessing the facebook using the blackberry api? if anybody has any solution or any useful link or any code snippet,which would be appreciated.:) Thanks, Mishal

    Read the article

  • target="_blank" link using jQuery UI Tabs

    - by Tim
    Hello, I would like to use my existing Jquery UI tabs to shoot my users off to a new browser window Unfortunately adding a target="_blank" to the jquery tab code doesn't work. Does anyone have any ideas? Here is the default Tab Code found here <div id="tabs"> <ul> <li><a href="#tabs-1">Nunc tincidunt</a></li> <li><a href="#tabs-2">Proin dolor</a></li> <li><a href="#tabs-3">Aenean lacinia</a></li> </ul> <div id="tabs-1"> <p>Proin elit arcu, rutrum commodo, vehicula tempus, commodo a, risus. Curabitur nec arcu. Donec sollicitudin mi sit amet mauris. Nam elementum quam ullamcorper ante. Etiam aliquet massa et lorem. Mauris dapibus lacus auctor risus. Aenean tempor ullamcorper leo. Vivamus sed magna quis ligula eleifend adipiscing. Duis orci. Aliquam sodales tortor vitae ipsum. Aliquam nulla. Duis aliquam molestie erat. Ut et mauris vel pede varius sollicitudin. Sed ut dolor nec orci tincidunt interdum. Phasellus ipsum. Nunc tristique tempus lectus.</p> </div> <div id="tabs-2"> <p>Morbi tincidunt, dui sit amet facilisis feugiat, odio metus gravida ante, ut pharetra massa metus id nunc. Duis scelerisque molestie turpis. Sed fringilla, massa eget luctus malesuada, metus eros molestie lectus, ut tempus eros massa ut dolor. Aenean aliquet fringilla sem. Suspendisse sed ligula in ligula suscipit aliquam. Praesent in eros vestibulum mi adipiscing adipiscing. Morbi facilisis. Curabitur ornare consequat nunc. Aenean vel metus. Ut posuere viverra nulla. Aliquam erat volutpat. Pellentesque convallis. Maecenas feugiat, tellus pellentesque pretium posuere, felis lorem euismod felis, eu ornare leo nisi vel felis. Mauris consectetur tortor et purus.</p> </div> <div id="tabs-3"> <p>Mauris eleifend est et turpis. Duis id erat. Suspendisse potenti. Aliquam vulputate, pede vel vehicula accumsan, mi neque rutrum erat, eu congue orci lorem eget lorem. Vestibulum non ante. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Fusce sodales. Quisque eu urna vel enim commodo pellentesque. Praesent eu risus hendrerit ligula tempus pretium. Curabitur lorem enim, pretium nec, feugiat nec, luctus a, lacus.</p> <p>Duis cursus. Maecenas ligula eros, blandit nec, pharetra at, semper at, magna. Nullam ac lacus. Nulla facilisi. Praesent viverra justo vitae neque. Praesent blandit adipiscing velit. Suspendisse potenti. Donec mattis, pede vel pharetra blandit, magna ligula faucibus eros, id euismod lacus dolor eget odio. Nam scelerisque. Donec non libero sed nulla mattis commodo. Ut sagittis. Donec nisi lectus, feugiat porttitor, tempor ac, tempor vitae, pede. Aenean vehicula velit eu tellus interdum rutrum. Maecenas commodo. Pellentesque nec elit. Fusce in lacus. Vivamus a libero vitae lectus hendrerit hendrerit.</p> </div> Thanks, Tim

    Read the article

  • asp.net mvc: handling no-javascript

    - by Bala R
    Hello, I'm working on a asp.net mvc2 app. I have been using jquery to do various different things in all of my views. They are work from a regular browser quite well. But I'm trying to figure out a good way to get the functionality working with browsers with javascript disabled (like mobile browsers). Is there a way to define a whole different view for non javascript browsers? A specific example of what I'm trying to do is, I have a with it's onClick calling a javascript that does $.post() to a controller. What's a good way to make it, so, it works the way it works right now (doing ajax calls) with regular javascript-enabled browsers and it a also works with javascript-incapable browsers, doing a full postback ? Thanks

    Read the article

  • What causes a JRE 6 JVM code cache leak?

    - by Arturo Knight
    Since switching to JRE 6, my server's code cache usage (non-heap) keeps growing indefinitely. My application creates a lot of classes at runtime, BUT these classes are successfully unloaded during the GC process. I can see these classes getting unloaded in the gc logs and also the permGen usage stays constant. I specifically make sure in my code that these classes are orphaned once I am finished with them and so they correctly get garbage collected from permGen. The code cache however keeps growing. I only became aware of the code cache after switching to JRE 6. So I guess my questions are: Does GC include the code cache? What could cause a code cache memory leak, specifically. Is there a bug in JDK 6 in this area?

    Read the article

  • Is it a bad idea if equals(null) throws NullPointerException instead?

    - by polygenelubricants
    The contract of equals with regards to null, is as follows: For any non-null reference value x, x.equals(null) should return false. This is rather peculiar, because if o1 != null and o2 == null, then we have: o1.equals(o2) // returns false o2.equals(o1) // throws NullPointerException The fact that o2.equals(o1) throws NullPointerException is a good thing, because it alerts us of programmer error. And yet, that error would not be catched if for various reasons we just switched it around to o1.equals(o2), which would just "silently fail" instead. So the questions are: Why is it a good idea that o1.equals(o2) should return false instead of throwing NullPointerException? Would it be a bad idea if wherever possible we rewrite the contract so that anyObject.equals(null) always throw NullPointerException instead?

    Read the article

< Previous Page | 411 412 413 414 415 416 417 418 419 420 421 422  | Next Page >