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  • NetBeans 7.1 Release Candidate (RC) 1 is here

    - by alexismp
    NetBeans 7.1 RC 1 is here. Grab it from the usual place! As previously discussed, NetBeans 7.1 has full JavaFX 2.0 support but also a lot in store for Java EE and Web developers (CDI in particular is very neat). One of my personal favorite feature is that Deploy on Save is now set by default on Maven projects. Maybe one important part that didn't get proper coverage so far is CSS 3 support, an important feature which can be used from both Java EE and PHP but also from JavaFX. Java Downloads of NetBeans 7.1 start at 69 MB and a 166 MB download will get you everything you need to start coding right away with Java EE - a great tool and a fully integrated runtime (GlassFish 3.1.1). You really need to be not using Maven, not be interested in recent standards (Java EE 6, Java SE 7, Java FX 2.0, ...) and like to hand-craft assemble your IDE to afford ignoring NetBeans nowadays.

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  • Ask the Experts on Silverlight TV

    Thanks to all of you Silverlight TV has really taken off. Were working hard to keep bringing in top, fresh and new content from great presenters. I think youll like what we have in store for the upcoming schedule! One new features for the show is Ask the Experts. During each show I will ask the guest one of your questions! Well be alerting everyone via Twitter about our speaker lineup in advance so you can send your questions to us. Just send your questions to us on Twitter at @SilverlightTV or...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • How to compare page views/visitors to site totals in Google Analytics?

    - by frntk
    I want to measure the effects in total traffic (views or visitors) of a single URL across a time frame. For example, let's say I published a blog post on July 2012. I want to measure what chunk of the site's total traffic is coming to this particular post on a month-by-month graph from July 2012 to date. Is there a way to do this? Edit: I should clarify that what I'd like to do is to generate a month-to-month graph, similar to the one you can see comparing a metric on a period of time against the previous equivalent period (year vs last year, for example) but comparing a particular URL traffic to the site's total traffic. In other words, I can get to the part where I can see the URL's traffic for the timeframe I selected and it shows how much of the total traffic corresponds to the current URL: But I'd like to add a second line to the graph, representing the site's total pageviews, similiar to this (but this one is showing just a different metric for the same URL): Thanks!

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  • Welcome!

    - by ilich
    Hello everyone! I am a Software Consultant, specializing in the Microsoft ecosystem and High Load Application, and this is my first blog. The decision to start it was pretty easy. I had woken up one day and decided to start doing something outside my daily job. I have to reasons to start the blog. The first one is I would like to learn from community. There are a lot of really good people here. The second reason is I need a place where I can share some tricks, hacks and useful pieces of code with the others. I will be glad to see if my blog helps somebody. Welcome on board!

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  • Release Notes for 10/04/2012

    Below are the release notes from this week's deployment. Upgrade to TFS 2012 We upgraded our TFS infrastructure earlier this week. This means you can now take advantage of several improvements when you are using Visual Studio 2012, such as Local Workspaces, merge on unshelve, rollback within VS UI, etc. Improvements and Bug Fixes Enabled the ability to create more than one pull request per fork using branches. Fixed a few issues in file browsing and diffs. Removed file line limit on full diff view. Several bug fixes within the project Fork experience Have ideas on how to improve CodePlex? Please visit our suggestions page! Vote for existing ideas or submit a new one. As always you can reach out to the CodePlex team on Twitter @codeplex or reach me directly @mgroves84

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  • What is the most handy function you've ever came across? [closed]

    - by Viniyo Shouta
    Obviously everything is 'handy' when it comes to programming terms, but some get a highlight spot, like containers, matrix trasnformation functions and many others. But in this case please mention the one it was more handy to you, saved you from sparing hours resolving a problem, or even the one you like more, What is it and what does it does? I'll start with an example. Language: C++ Function: std::sort (STL) What does it does: Arranges the elements in a specified range into a nondescending order or according to an ordering criterion specified by a binary predicate. (It arranges a container in decreasing order) Why of this question? Because I want to learn how to if possible make my own implementations of these functions for pure studying purposes, to enhance knowledge

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  • Manually change the screen resolution

    - by Dz WarSoldier
    My system: Ubuntu 12.04 LTS. My graphic card: nVidia GeForce gt430. My monitor is Samsung LE26R51B. And my connection is digital (HDMI). The current screen resolution is not good at all, I can't see the top bar and the left one. Here are the available resolutions in settings: 1920*1080 1280*720 960*600 and lower resolutions But with no one of these I can see the top bar in it. They are bigger than the monitor. In Windows 7 I use 1202*670 resolution. How can I change the resolution to what I want exactly?

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  • Forbidding or controlling "Hidden IT..." Who should write and maintain ad-hoc software applications?

    - by matcauthon
    Bigger companies usually have the problem, that it is not possible to write all programs employees want (to save time and to optimize processes) due to a lack of staff and money. Then hidden programs will be created by some people having (at least some) coding experience (or by cheap students/interns...). Under some circumstances these applications will raise in importance and spread from one user to a whole department. Then there is the critical point: Who will maintain the application, add new features, ...? And this app is critical. It IS needed. But the intern has left the company. No one knows how it works. You only have a bunch of sources and some sort of documentation. Does it make sense to try and control or forbid application development done ad-hoc outside of the IT department (with the exception of minor stuff like Excel macros)?

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  • Eudora

    One of the very first standalone e-mail clients to hit the 'net and now an open-source e-mail app

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  • PDF Merge

    This Windows application lets you merge image and PDF files in a given folder into one PDF file.

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  • Single statement if block - braces or no? [on hold]

    - by Zannjaminderson
    Which is better/more generally accepted? This: if(condition) { statement; } Or: if(condition) statement; I tend to prefer the first one, because I think it makes it easier to tell what actually belongs in the if block, it saves others from adding the braces later (or creating a bug by forgetting to), and it makes all your if statements uniform instead of some with braces and some without. The second one, however, is still syntactically correct and definitely more compact. I'm curious to see which is more generally preferred by others though.

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  • ???????????????:????????????

    - by ???02
    ???????????????:??????????????????????????????????????????????????????????ID?????????????Oracle Identity Manager????????????????????Oracle Database Vault???????·?????Oracle Audit Vault????????????????·????????????????????????????????????????????·?????????·?????????????????????????????? ?????????????????????????(????????????????????)???·????????????????????? ???????????????????????????·???????????????????????????????????Oracle Database Vault ~???????????Oracle Database Vault??????????????????????????????(DBA)??????·?????????????????????????????????????????????????????????Oracle Database Vault ~???????????????????????????????????????????????????????????????????????????????????????????????IP????????????????????????????????????????????9:00-17:00?????????????????????????????????????????????????????????????????????????????????????????????????????????????????Oracle Audit Vault ~???????????????????????????????????????·??????????·DBA???????????????????????????????????????????????????????????????????Oracle Audit Vault???Oracle Audit Vault??Oracle Database Vault???????????????????????????????????ID????????????????????????ID????????????????????????????????????????????Oracle Database Standard Edition?Oracle Database Standard Edition One??????????????????Oracle Database Vault???????????Unix?Linux???OS???????????????????????Oracle Database(EE / SE / SE One)??????????????OS??????????????Oracle Identity Manager(???OIM)??????OIM??????????????????????????????ID???????????????ID???·?????????????????ID?????????????????ID????????????????·???????????Oracle Identity Manager ~ID??·????·??????OIM????????????????????(???/???????????)??????????????????????????ID??·? ???·?????????????????????????????????????ID????????????????????????????? ????Oracle Identity Manager ~??·????????????????????ID???????????????????????????????????????OIM?????????????????????????????????????Oracle Identity Manager ~??·??????????????????????1?????????????????????????????????????????????????????????????????Oracle Identity Manager ~????????????????????OIM??ID????????????????????????????????????????????????????????????????? ??40???????????????????????????????????????????????????????????????????? ????????????????????PDF?Office??????????????????????????? Oracle Direct

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  • Animating the offset of the scrollView in a UICollectionView/UITableView causes prematurely disappearing cells

    - by radutzan
    We have a UICollectionView with a custom layout very similar to UITableView (it scrolls vertically). The UICollectionView displays only 3 cells simultaneously, with one of them being the currently active cell: [ 1 ] [*2*] [ 3 ] (The active cell here is #2.) The cells are roughly 280 points high, so only the active cell is fully visible on the screen. The user doesn't directly scroll the view to navigate, instead, she swipes the active cell horizontally to advance to the next cell. We then do some fancy animations and scroll the UICollectionView so the next cell is in the "active" position, thus making it the active one, moving the old one away and bringing up the next cell in the queue: [ 2 ] [*3*] [ 4 ] The problem here is setting the UICollectionView's offset. We currently set it in a UIView animation block (self.collectionView.contentOffset = targetOffset;) along with three other animating properties, which mostly works great, but causes the first cell (the previously active one, in the latter case, #2) to vanish as soon as the animation starts running, even before the delay interval completes. This is definitely not ideal. I've thought of some solutions, but can't figure out the best one: Absurdly enlarge the UICollectionView's frame to fit five cells instead of three, thus forcing it to keep the cells in memory even if they are offscreen. I've tried this and it works, but it sounds like an awfully dirty hack. Take a snapshot of the rendered content of the vanishing cell, put it in a UIImageView, add the UIImageView as a subview of the scrollView just before the cell goes away in the exact same position of the old cell, removing it once the animation ends. Sounds less sucky than the previous option (memory-wise, at least), but still kinda hacky. I also don't know the best way to accomplish this, please point me in the right direction. Switch to UIScrollView's setContentOffset:animated:. We actually used to have this, and it fixed the disappearing cell issue, but running this in parallel with the other UIView animations apparently competes for the attention of the main thread, thus creating a terribly choppy animation on single-core devices (iPhone 3GS/4). It also doesn't allow us to change the duration or easing of the animation, so it feels out of sync with the rest. Still an option if we can find a way to make it work in harmony with the UIView block animations. Switch to UICollectionView's scrollToItemAtIndexPath:atScrollPosition:animated:. Haven't tried this, but it has a big downside: it only takes 3 possible constants (that apply to this case, at least) for the target scroll position: UICollectionViewScrollPositionTop, UICollectionViewScrollPositionCenteredVertically and UICollectionViewScrollPositionBottom. The active cell could vary its height, but it always has to be 35 points from the top of the window, and these options don't provide enough control to accomplish the design. It could also potentially be just as problematic as 3.1. Still an option because there might be a way to go around the scroll position thing that I don't know of, and it might not have the same issue with the main thread, which seems unlikely. Any help will be greatly appreciated. Please ask if you need clarification. Thanks a lot!

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  • Help With Database Layout

    - by three3
    Hello everyone, I am working on a site similar to Craigslist where users can make postings and sell items in different cities. One difference between my site and Craigslist will be you will be able to search by zip code instead of having all of the cities listed on the page. I already have the ZIP Code database that has all of the city, state, latitude, longitude, and zip code info for each city. Okay, so to dive into what I need done and what I need help with: 1.) Although I have the ZIP Code database, it is not setup perfectly for my use. (I downloaded it off of the internet for free from http://zips.sourceforge.net/) 2.) I need help setting up my database structure (Ex: How many different tables should I use and how should I link them) I will be using PHP and MySQL. These our my thoughts so far on how the database can be setup: (I am not sure if this will work though.) Scenario: Someone goes to the homepage and it will tell them, "Please enter your ZIP Code.". If they enter "17241" for example, this ZIP Code is for a city named Newville located in Pennsylvania. The query would look like this with the current database setup: SELECT city FROM zip_codes WHERE zip = 17241; The result of the query would be "Newville". The problem I see here now is when they want to post something in the Newville section of the site, I will have to have an entire table setup just for the Newville city postings. There are over 42,000 cities which means I would have to have over 42,000 tables (one for each city) so that would be insane to have to do it that way. One way I was thinking of doing it was to add a column to the ZIP Code database called "city_id" which would be a unique number assigned to each city. So for example, the city Newville would have a city_id of 83. So now if someone comes and post a listing in the city Newville I would only need one other table. That one other table would be setup like this: CREATE TABLE postings ( posting_id INT NOT NULL AUTO_INCREMENT, for_sale LONGTEXT NULL, for_sale_date DATETIME NULL, for_sale_city_id INT NULL, jobs LONGTEXT NULL, jobs_date DATETIME NULL, jobs_city_id INT NULL, PRIMARY KEY(posting_id) ); (The for_sale and job_ column names are categories of the types of postings users will be able to list under. There will be many more categories than just those two but this is just for example.) So now when when someone comes to the website and they are looking for something to buy and not sell, they can enter their ZIP Code, 17241, for example, and this is the query that will run: SELECT city, city_id FROM zip_codes WHERE zip = 17241; //Result: Newville 83 (Please note that I will be using PHP to store the ZIP Code the user enters in SESSIONS and Cookies to remember them throughout the site) Now it will tell them, "Please choose your category.". If they choose the category "Items For Sale" then this is the query to run and sort the results: SELECT posting_id, for_sale, for_sale_date FROM postings WHERE for_sale_city_id = $_SESSION['zip_code']; Will this work? So now my question to everyone is will this work? I am pretty sure it will but I do not want to set this thing up and realize I overlooked something and have to start from all over from scratch. Any opinions and ideas are welcomed and I will listen to anyone who has some thoughts. I really appreciate the help in advance :D

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  • Git for beginners: The definitive practical guide

    - by Adam Davis
    Ok, after seeing this post by PJ Hyett, I have decided to skip to the end and go with git. So what I need is a beginners practical guide to git. "Beginner" being defined as someone who knows how to handle their compiler, understands to some level what a makefile is, and has touched source control without understanding it very well. "Practical" being defined as this person doesn't want to get into great detail regarding what git is doing in the background, and doesn't even care (or know) that it's distributed. Your answers might hint at the possibilities, but try to aim for the beginner that wants to keep a 'main' repository on a 'server' which is backed up and secure, and treat their local repository as merely a 'client' resource. Procedural note: PLEASE pick one and only one of the below topics and answer it clearly and concisely in any given answer. Don't try to jam a bunch of information into one answer. Don't just link to other resources - cut and paste with attribution if copyright allows, otherwise learn it and explain it in your own words (ie, don't make people leave this page to learn a task). Please comment on, or edit, an already existing answer unless your explanation is very different and you think the community is better served with a different explanation rather than altering the existing explanation. So: Installation/Setup How to install git How do you set up git? Try to cover linux, windows, mac, think 'client/server' mindset. Setup GIT Server with Msysgit on Windows How do you create a new project/repository? How do you configure it to ignore files (.obj, .user, etc) that are not really part of the codebase? Working with the code How do you get the latest code? How do you check out code? How do you commit changes? How do you see what's uncommitted, or the status of your current codebase? How do you destroy unwanted commits? How do you compare two revisions of a file, or your current file and a previous revision? How do you see the history of revisions to a file? How do you handle binary files (visio docs, for instance, or compiler environments)? How do you merge files changed at the "same time"? How do you undo (revert or reset) a commit? Tagging, branching, releases, baselines How do you 'mark' 'tag' or 'release' a particular set of revisions for a particular set of files so you can always pull that one later? How do you pull a particular 'release'? How do you branch? How do you merge branches? How do you resolve conflicts and complete the merge? How do you merge parts of one branch into another branch? What is rebasing? How do I track remote branches? How can I create a branch on a remote repository? Other Describe and link to a good gui, IDE plugin, etc that makes git a non-command line resource, but please list its limitations as well as its good. msysgit - Cross platform, included with git gitk - Cross platform history viewer, included with git gitnub - OS X gitx - OS X history viewer smartgit - Cross platform, commercial, beta tig - console GUI for Linux qgit - GUI for Windows, Linux Any other common tasks a beginner should know? Git Status tells you what you just did, what branch you have, and other useful information How do I work effectively with a subversion repository set as my source control source? Other git beginner's references git guide git book git magic gitcasts github guides git tutorial Progit - book by Scott Chacon Git - SVN Crash Course Delving into git Understanding git conceptually I will go through the entries from time to time and 'tidy' them up so they have a consistent look/feel and it's easy to scan the list - feel free to follow a simple "header - brief explanation - list of instructions - gotchas and extra info" template. I'll also link to the entries from the bullet list above so it's easy to find them later.

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  • How is WPF Data Binding using Object Data Source in Visual Studio 2010 done?

    - by Rob Perkins
    This is probably mostly a question about how to use the VS 2010 IDE tools in a way the Microsofties didn't specifically intend. But since this is something I immediately tried without success. I have defined a .NET 4.0 WPF Application project with a simple class that looks like this: Public Class Class1 Public Property One As String = "OneString" Public Property Two As String = "TwoString" End Class I then defined it as an "Object Data Source" in VS2010, using the IDE's "Add New Data Source..." feature. This exposes the class members in a GUI element in the IDE as given in this image: Dragging "Class1" from that tool to the surface of "Window1.xaml" in a default "WPF Application" results in the design view looking like this: And generated XAML like this: <Window x:Class="Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="133" Width="170" xmlns:my="clr-namespace:WpfApplication1" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" > <Window.Resources> <CollectionViewSource x:Key="Class1ViewSource" d:DesignSource="{d:DesignInstance my:Class1, CreateList=True}" /> </Window.Resources> <Grid DataContext="{StaticResource Class1ViewSource}" HorizontalAlignment="Left" Name="Grid1" VerticalAlignment="Top"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="Auto" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <Label Content="One:" Grid.Column="0" Grid.Row="0" HorizontalAlignment="Left" Margin="3" VerticalAlignment="Center" /> <TextBlock Grid.Column="1" Grid.Row="0" Height="23" HorizontalAlignment="Left" Margin="3" Name="OneTextBlock" Text="{Binding Path=One}" VerticalAlignment="Center" /> <Label Content="Two:" Grid.Column="0" Grid.Row="1" HorizontalAlignment="Left" Margin="3" VerticalAlignment="Center" /> <TextBlock Grid.Column="1" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="3" Name="TwoTextBlock" Text="{Binding Path=Two}" VerticalAlignment="Center" /> </Grid> Note the data bindings Text="{Binding Path=One}" and Text="{Binding Path=Two}" in the TextBlock elements. Code-behind for Window1.xaml has this in Window_Loaded: Class Window1 Private m_c1 As New Class1 Private Sub Window1_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded Dim Class1ViewSource As System.Windows.Data.CollectionViewSource = CType(Me.FindResource("Class1ViewSource"), System.Windows.Data.CollectionViewSource) 'Load data by setting the CollectionViewSource.Source property: 'Class1ViewSource.Source = [generic data source] Me.DataContext = m_c1 End Sub End Class Running the application produces this output: The expected result was that "OneString" would appear next to "One" and "TwoString" next to "Two" in the running window. The question is: Why didn't this work? What will work instead? If I put bindings in a DataTemplate, it works. Blend, with its sample data stuff, implied that this should work, but it doesn't. I know I'm missing something pretty fundamental here; what is it?

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  • What precautions should you take when a senior employee leaves?

    - by Mahin
    EDIT : I agree one should check the reasons, why a senior level employee is leaving. But I am interested in knowing the official/management/technical/legal steps one should take after its decided that he is leaving, so that the life after him is smooth. What are the steps management should take when a senior programmer/team lead leaves your company. Some of them which I have thought about are : 1) If He used to manage hosting and domains stuff, change passwords of domain control panels and hosting panels. 2) If your published web sites have maintenance account and he is aware of credentials of that account then change this details also. 3) Suspend mail account for some time and forward all eMails of that account to some ex-employee account. After some time close that account. What are the other things one should check. I am expecting the answer to be a general check list one should follow. It should include both technical scenarios and management scenarios. Notable Suggestions so far : Effectively transfer the responsibilities of that employee to another one without causing any potential delay in your work. Protect your source code. If possible Make them to sign something to say that they don't have copies of source code.. You can also consider NDA here. Use the Notice Period to train his replacement. Now any new code to the project will be done by replacement with the help of Guy who is leaving. Ask him to create a document of things he thinks you should know. Make sure he checks everything in now and then any checkout will only be done by the replacement. Emails, copy off his email account to a pst.file (this assumes Outlook), Make this file available to his replacement. the employee should probably be given a chance to scrub the email. if you are going to keep his account open for whatever reason, check that no rules are created that forward incoming emails to an alternate address. Copy the hard drive of his computer to a network location and have someone senior go through and see if there are any files (drafts of performance reviews or other sensitive issues ) on it that someone else might need. Clearance from Accounts,Finance,Security,Library etc departments.Obtain all company property, laptops, keys, etc. If there is no reason not to, you should reward a departing person for their many years of service. Write them letters of recommendation (even if they already have a new job lined up).Say goodbye, and keep the door open. Make sure any outside clients know that the departing employee is not their main contact anymore. Never neglect the exit interview/debriefing. Confirm the last day of employment so that there is no misunderstanding Inform H/R if the employee is on H1B status, there is paperwork required to notify the government when an H1B employee leaves. Depending on how senior / what position, you might spend some time convincing him not to take the rest of the engineering staff with him. Make sure he spends his last days on a good note, because if he is not leaving on a good note, he can easily pollute the mind of his colleagues. Best Regards, Mahin Gupta EDIT : Now offered a bounty on it to get more detailed responses and practical suggestions.

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  • Fluent NHibernate - subclasses with shared reference

    - by ollie
    Edit: changed class names. I'm using Fluent NHibernate (v 1.0.0.614) automapping on the following set of classes (where Entity is the base class provided in the S#arp Architecture framework): public class Car : Entity { public virtual int ModelYear { get; set; } public virtual Company Manufacturer { get; set; } } public class Sedan : Car { public virtual bool WonSedanOfYear { get; set; } } public class Company : Entity { public virtual IList<Sedan> Sedans { get; set; } } This results in the following Configuration (as written to hbm.xml): <class name="Company" table="Companies"> <id name="Id" type="System.Int32" unsaved-value="0"> <column name="`ID`" /> <generator class="identity" /> </id> <bag cascade="all" inverse="true" name="Sedans" mutable="true"> <key> <column name="`CompanyID`" /> </key> <one-to-many class="Sedan" /> </bag> </class> <class name="Car" table="Cars"> <id name="Id" type="System.Int32" unsaved-value="0"> <column name="`ID`" /> <generator class="identity" /> </id> <property name="ModelYear" type="System.Int32"> <column name="`ModelYear`" /> </property> <many-to-one cascade="save-update" class="Company" name="Manufacturer"> <column name="`CompanyID`" /> </many-to-one> <joined-subclass name="Sedan"> <key> <column name="`CarID`" /> </key> <property name="WonSedanOfYear" type="System.Boolean"> <column name="`WonSedanOfYear`" /> </property> </joined-subclass> </class> So far so good! But now comes the ugly part. The generated database tables: Table: Companies Columns: ID (PK, int, not null) Table: Cars Columns: ID (PK, int, not null) ModelYear (int, null) CompanyID (FK, int, null) Table: Sedan Columns: CarID (PK, FK, int, not null) WonSedanOfYear (bit, null) CompanyID (FK, int, null) Instead of one FK for Company, I get two! How can I ensure I only get one FK for Company? Override the automapping? Put a convention in place? Or is this a bug? Your thoughts are appreciated.

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  • Tomcat stops responding to JK requests

    - by Bruno Reis
    Hello. I have a nasty issue with load-balanced Tomcat servers that are hanging up. Any help would be greatly appreciated. The system I'm running Tomcat 6.0.26 on HotSpot Server 14.3-b01 (Java 1.6.0_17-b04) on three servers sitting behind another server that acts as load balancer. The load balancer runs Apache (2.2.8-1) + MOD_JK (1.2.25). All of the servers are running Ubuntu 8.04. The Tomcat's have 2 connectors configured: an AJP one, and a HTTP one. The AJP is to be used with the load balancer, while the HTTP is used by the dev team to directly connect to a chosen server (if we have a reason to do so). I have Lambda Probe 1.7b installed on the Tomcat servers to help me diagnose and fix the problem soon to be described. The problem Here's the problem: after about 1 day the application servers are up, JK Status Manager starts reporting status ERR for, say, Tomcat2. It will simply get stuck on this state, and the only fix I've found so far is to ssh the box and restart Tomcat. I must also mention that JK Status Manager takes a lot longer to refresh when there's a Tomcat server in this state. Finally, the "Busy" count of the stuck Tomcat on JK Status Manager is always high, and won't go down per se -- I must restart the Tomcat server, wait, then reset the worker on JK. Analysis Since I have 2 connectors on each Tomcat (AJP and HTTP), I still can connect to the application through the HTTP one. The application works just fine like this, very, very fast. That is perfectly normal, since I'm the only one using this server (as JK stopped delegating requests to this Tomcat). To try to better understand the problem, I've taken a thread dump from a Tomcat which is not responding anymore, and from another one that has been restarted recently (say, 1 hour before). The instance that is responding normally to JK shows most of the TP-ProcessorXXX threads in "Runnable" state, with the following stack trace: java.net.SocketInputStream.socketRead0 ( native code ) java.net.SocketInputStream.read ( SocketInputStream.java:129 ) java.io.BufferedInputStream.fill ( BufferedInputStream.java:218 ) java.io.BufferedInputStream.read1 ( BufferedInputStream.java:258 ) java.io.BufferedInputStream.read ( BufferedInputStream.java:317 ) org.apache.jk.common.ChannelSocket.read ( ChannelSocket.java:621 ) org.apache.jk.common.ChannelSocket.receive ( ChannelSocket.java:559 ) org.apache.jk.common.ChannelSocket.processConnection ( ChannelSocket.java:686 ) org.apache.jk.common.ChannelSocket$SocketConnection.runIt ( ChannelSocket.java:891 ) org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run ( ThreadPool.java:690 ) java.lang.Thread.run ( Thread.java:619 ) The instance that is stuck show most (all?) of the TP-ProcessorXXX threads in "Waiting" state. These have the following stack trace: java.lang.Object.wait ( native code ) java.lang.Object.wait ( Object.java:485 ) org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run ( ThreadPool.java:662 ) java.lang.Thread.run ( Thread.java:619 ) I don't know of the internals of Tomcat, but I would infer that the "Waiting" threads are simply threads sitting on a thread pool. So, if they are threads waiting inside of a thread pool, why wouldn't Tomcat put them to work on processing requests from JK? Solution? So, as I've stated before, the only fix I've found is to stop the Tomcat instance, stop the JK worker, wait the latter's busy count slowly go down, start Tomcat again, and enable the JK worker once again. What is causing this problem? How should I further investigate it? What can I do to solve it? Thanks in advance.

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  • WebSphere Application Server EJB Optimization

    - by Chris Aldrich
    We are working on developing a Java EE based application. Our application is Java 1.5 compatible and will be deployed to WAS ND 6.1.0.21 with EBJ 3.0 and Web Services feature packs. The configuration is currently one cell with two clusters. Each cluster will have two nodes. Our application, or our system, as I should rather say, comes in two or three parts. Part 1: An ear deployed to one cluster that contains 3rd party vendor code combined with customization code. Their code is EJB 2.0 compliant and has a lot of Remote Home interfaces. Part 2: An ear deployed to the same cluster as the first ear. This ear contains EBJ 3's that make calls into the EJB 2's supplied by the vendor and the custom code. These EJB 3's are used by the JSF UI also packaged with the EAR, and some of them are also exposed as web services (JAX-WS 2.0 with SOAP 1.2 compliance) for other clients. Part 3: There may be other services that do not depend on our vendor/custom code app. These services will be EJB 3.0's and web services that are deployed to the other cluster. Per a recommendation from some IBM staff on site here, communication between nodes in a cluster can be EJB RMI. But if we are going across clusters and/or other cells, then the communication should be web services. That said, some of us are wondering about performance and optimizing communication for speed of our applications that will use our web services and EJB's. Right now most EJB's are exposed as remote. (and our vendor set theirs up that way, rather than also exposing local home interfaces). We are wondering if WAS does any optimizations between apps in the same node/cluster node space. If two apps are installed in the same area and they call each other via remote home interface, is WAS smart enough to make it a local home interface call? Are their other optimization techniques? Should we consider them? Should we not? What are the costs/benefits? Here is the question from one of our team members as sent in their email: The question is: Supposing we develop our EJBs as remote EJBs, where our UI controller code is talking to our EXT java services via EJB3...what are our options for performance optimization when both the EJB server and client are running in the same container? As one point of reference, google has given me some oooooold websphere performance tuning documentation from 2000 that explains a tuning configuration you can set to enable Call By Reference for EJB communication when they're in the same application server JVM. It states the following: Because EJBs are inherently location independent, they use a remote programming model. Method parameters and return values are serialized over RMI-IIOP and returned by value. This is the intrinsic RMI "Call By Value" model. WebSphere provides the "No Local Copies" performance optimization for running EJBs and clients (typically servlets) in the same application server JVM. The "No Local Copies" option uses "Call By Reference" and does not create local proxies for called objects when both the client and the remote object are in the same process. Depending on your workload, this can result in a significant overhead savings. Configure "No Local Copies" by adding the following two command line parameters to the application server JVM: * -Djavax.rmi.CORBA.UtilClass=com.ibm.CORBA.iiop.Util * -Dcom.ibm.CORBA.iiop.noLocalCopies=true CAUTION: The "No Local Copies" configuration option improves performance by changing "Call By Value" to "Call By Reference" for clients and EJBs in the same JVM. One side effect of this is that the Java object derived (non-primitive) method parameters can actually be changed by the called enterprise bean. Consider Figure 16a: Also, we will also be using Process Server 6.2 and WESB 6.2 as well in the future. Any ideas? recommendations? Thanks

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  • Is it possible to implement bitwise operators using integer arithmetic?

    - by Statement
    Hello World! I am facing a rather peculiar problem. I am working on a compiler for an architecture that doesn't support bitwise operations. However, it handles signed 16 bit integer arithmetics and I was wondering if it would be possible to implement bitwise operations using only: Addition (c = a + b) Subtraction (c = a - b) Division (c = a / b) Multiplication (c = a * b) Modulus (c = a % b) Minimum (c = min(a, b)) Maximum (c = max(a, b)) Comparisons (c = (a < b), c = (a == b), c = (a <= b), et.c.) Jumps (goto, for, et.c.) The bitwise operations I want to be able to support are: Or (c = a | b) And (c = a & b) Xor (c = a ^ b) Left Shift (c = a << b) Right Shift (c = a b) (All integers are signed so this is a problem) Signed Shift (c = a b) One's Complement (a = ~b) (Already found a solution, see below) Normally the problem is the other way around; how to achieve arithmetic optimizations using bitwise hacks. However not in this case. Writable memory is very scarce on this architecture, hence the need for bitwise operations. The bitwise functions themselves should not use a lot of temporary variables. However, constant read-only data & instruction memory is abundant. A side note here also is that jumps and branches are not expensive and all data is readily cached. Jumps cost half the cycles as arithmetic (including load/store) instructions do. On other words, all of the above supported functions cost twice the cycles of a single jump. Some thoughts that might help: I figured out that you can do one's complement (negate bits) with the following code: // Bitwise one's complement b = ~a; // Arithmetic one's complement b = -1 - a; I also remember the old shift hack when dividing with a power of two so the bitwise shift can be expressed as: // Bitwise left shift b = a << 4; // Arithmetic left shift b = a * 16; // 2^4 = 16 // Signed right shift b = a >>> 4; // Arithmetic right shift b = a / 16; For the rest of the bitwise operations I am slightly clueless. I wish the architects of this architecture would have supplied bit-operations. I would also like to know if there is a fast/easy way of computing the power of two (for shift operations) without using a memory data table. A naive solution would be to jump into a field of multiplications: b = 1; switch (a) { case 15: b = b * 2; case 14: b = b * 2; // ... exploting fallthrough (instruction memory is magnitudes larger) case 2: b = b * 2; case 1: b = b * 2; } Or a Set & Jump approach: switch (a) { case 15: b = 32768; break; case 14: b = 16384; break; // ... exploiting the fact that a jump is faster than one additional mul // at the cost of doubling the instruction memory footprint. case 2: b = 4; break; case 1: b = 2; break; }

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