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• Solaris 11.1: Encrypted Immutable Zones on (ZFS) Shared Storage

  - by darrenm

  Solaris 11 brought both ZFS encryption and the Immutable Zones feature and I've talked about the combination in the past.  Solaris 11.1 adds a fully supported method of storing zones in their own ZFS using shared storage so lets update things a little and put all three parts together. When using an iSCSI (or other supported shared storage target) for a Zone we can either let the Zones framework setup the ZFS pool or we can do it manually before hand and tell the Zones framework to use the one we made earlier.  To enable encryption we have to take the second path so that we can setup the pool with encryption before we start to install the zones on it. We start by configuring the zone and specifying an rootzpool resource: # zonecfg -z eizoss Use 'create' to begin configuring a new zone. zonecfg:eizoss> create create: Using system default template 'SYSdefault' zonecfg:eizoss> set zonepath=/zones/eizoss zonecfg:eizoss> set file-mac-profile=fixed-configuration zonecfg:eizoss> add rootzpool zonecfg:eizoss:rootzpool> add storage \ iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 zonecfg:eizoss:rootzpool> end zonecfg:eizoss> verify zonecfg:eizoss> commit zonecfg:eizoss> Now lets create the pool and specify encryption: # suriadm map \ iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 PROPERTY VALUE mapped-dev /dev/dsk/c10t600144F09ACAACD20000508E64A70001d0 # echo "zfscrypto" > /zones/p # zpool create -O encryption=on -O keysource=passphrase,file:///zones/p eizoss \ /dev/dsk/c10t600144F09ACAACD20000508E64A70001d0 # zpool export eizoss Note that the keysource example above is just for this example, realistically you should probably use an Oracle Key Manager or some other better keystorage, but that isn't the purpose of this example.  Note however that it does need to be one of file:// https:// pkcs11: and not prompt for the key location.  Also note that we exported the newly created pool.  The name we used here doesn't actually mater because it will get set properly on import anyway. So lets go ahead and do our install: zoneadm -z eizoss install -x force-zpool-import Configured zone storage resource(s) from: iscsi://zs7120-tvp540-c.uk.oracle.com/luname.naa.600144f09acaacd20000508e64a70001 Imported zone zpool: eizoss_rpool Progress being logged to /var/log/zones/zoneadm.20121029T115231Z.eizoss.install Image: Preparing at /zones/eizoss/root. AI Manifest: /tmp/manifest.xml.ujaq54 SC Profile: /usr/share/auto_install/sc_profiles/enable_sci.xml Zonename: eizoss Installation: Starting ... Creating IPS image Startup linked: 1/1 done Installing packages from: solaris origin: http://pkg.us.oracle.com/solaris/release/ Please review the licenses for the following packages post-install: consolidation/osnet/osnet-incorporation (automatically accepted, not displayed) Package licenses may be viewed using the command: pkg info --license <pkg_fmri> DOWNLOAD PKGS FILES XFER (MB) SPEED Completed 187/187 33575/33575 227.0/227.0 384k/s PHASE ITEMS Installing new actions 47449/47449 Updating package state database Done Updating image state Done Creating fast lookup database Done Installation: Succeeded Note: Man pages can be obtained by installing pkg:/system/manual done. Done: Installation completed in 929.606 seconds. Next Steps: Boot the zone, then log into the zone console (zlogin -C) to complete the configuration process. Log saved in non-global zone as /zones/eizoss/root/var/log/zones/zoneadm.20121029T115231Z.eizoss.install That was really all we had to do, when the install is done boot it up as normal. The zone administrator has no direct access to the ZFS wrapping keys used for the encrypted pool zone is stored on.  Due to how inheritance works in ZFS he can still create new encrypted datasets that use those wrapping keys (without them ever being inside a process in the zone) or he can create encrypted datasets inside the zone that use keys of his own choosing, the output below shows the two cases: rpool is inheriting the key material from the global zone (note we can see the value of the keysource property but we don't use it inside the zone nor does that path need to be (or is) accessible inside the zone). Whereas rpool/export/home/bob has set keysource locally. # zfs get encryption,keysource rpool rpool/export/home/bob NAME PROPERTY VALUE SOURCE rpool encryption on inherited from $globalzone rpool keysource passphrase,file:///zones/p inherited from $globalzone rpool/export/home/bob encryption on local rpool/export/home/bob keysource passphrase,prompt local  

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• Best approach to depth streaming via existing codec

  - by Kevin

  I'm working on a development system (and game) intended for games set mostly in static third-person views. We produce our scenery by CG and photographic techniques. Our background art is rendered off-line by a production-grade renderer. To allow the runtime imagery to properly interact with the background art, I wrote a program to convert from depth output by Mental Ray into a texture, and a pixel shader to draw a quad such that the Z data comes from the texture. This technique is working out very well, but now we've decided that some of the camera angle changes between scenes should be animated. The animation itself is straightforward to produce from our CG models. We intend to encode it to some HD video codec such as H.264. The problem is that in order to maintain our runtime imagery on the screen, the depth buffer will need to be loaded for each video frame. Due to the bandwidth, the video's depth data will need to be compressed efficiently. I've looked into methods for performing temporal compression of depth info and found an interesting research paper here: http://web4.cs.ucl.ac.uk/staff/j.kautz/publications/depth-streaming.pdf The method establishes a mapping between 16-bit depth values and YCbCr values. The mapping is tuned to the properties of existing video codecs in order to maximize precision of the decoded depths after the YCbCr has undergone video compression. It allows an existing, unmodified video codec to be used on the backend. I'm looking at how to pull this off with the least possible work. (This design change was unplanned.) Our game engine itself is native C++, presently for Win32 and DirectX, although we've worked hard to keep platform dependence segregated because we intend other ports. We don't have motion video facilities in the engine yet but will ultimately need that anyway for cinematics. I was planning on using some off-the-shelf motion video solution we can plug into our engine, and haven't chosen one yet. This new added requirement makes selecting one harder since, among other things, we'll now need to bypass colourspace conversion on one of the streams, and also will need to be playing two streams simultaneously in lockstep, on top of in some cases audio on one of them (for the cinematics). I'm also wondering if it's possible (or even useful) to do the conversion from YCbCr to depth in a pixel shader, or if it's better to just do it in CPU and separately load the resulting depth values into a locked tex. The conversion unfortunately does involve branching logic per-pixel. (There are more naive mappings that don't need branching, but they produce inferior results.) It could be reduced to a table lookup but the table would be 32MB. Programming is second-nature to me but I'm not that experienced with pix shaders and have zero knowledge of off-the-shelf video solutions. I'd therefore be interested in advice from others who may have dealt more with depth streaming, pixel shaders, and/or off-the-shelf codecs, regarding how feasible the proposed application is and what off-the-shelf video systems out there would best get along with this usage case.

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• PowerShell Script To Find Where SharePoint 2007 Features Are Activated

  - by Brian T. Jackett

  Recently I posted a script to find where SharePoint 2010 Features Are Activated.  I built the original version to use SharePoint 2010 PowerShell commandlets as that saved me a number of steps for filtering and gathering features at each level.  If there was ever demand for a 2007 version I could modify the script to handle that by using the object model instead of commandlets.  Just the other week a fellow SharePoint PFE Jason Gallicchio had a customer asking about a version for SharePoint 2007.  With a little bit of work I was able to convert the script to work against SharePoint 2007.   Solution    Below is the converted script that works against a SharePoint 2007 farm.  Note: There appears to be a bug with the 2007 version that does not give accurate results against a SharePoint 2010 farm.  I ran the 2007 version against a 2010 farm and got fewer results than my 2010 version of the script.  Discussing with some fellow PFEs I think the discrepancy may be due to sandboxed features, a new concept in SharePoint 2010.  I have not had enough time to test or confirm.  For the time being only use the 2007 version script against SharePoint 2007 farms and the 2010 version against SharePoint 2010 farms.    Note: This script is not optimized for medium to large farms.  In my testing it took 1-3 minutes to recurse through my demo environment.  This script is provided as-is with no warranty.  Run this in a smaller dev / test environment first. 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 function Get-SPFeatureActivated { # see full script for help info, removed for formatting [CmdletBinding()] param(     [Parameter(position = 1, valueFromPipeline=$true)]     [string]     $Identity )#end param     Begin     {         # load SharePoint assembly to access object model         [void][System.Reflection.Assembly]::LoadWithPartialName("Microsoft.SharePoint")             # declare empty array to hold results. Will add custom member for Url to show where activated at on objects returned from Get-SPFeature.         $results = @()                 $params = @{}     }     Process     {         if([string]::IsNullOrEmpty($Identity) -eq $false)         {             $params = @{Identity = $Identity}         }                 # create hashtable of farm features to lookup definition ids later         $farm = [Microsoft.SharePoint.Administration.SPFarm]::Local                         # check farm features         $results += ($farm.FeatureDefinitions | Where-Object {$_.Scope -eq "Farm"} | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                          % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value ([string]::Empty) -PassThru} |                          Select-Object -Property Scope, DisplayName, Id, Url)                 # check web application features         $contentWebAppServices = $farm.services | ? {$_.typename -like "Windows SharePoint Services Web Application"}                 foreach($webApp in $contentWebAppServices.WebApplications)         {             $results += ($webApp.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                          % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $webApp.GetResponseUri(0).AbsoluteUri -PassThru} |                          Select-Object -Property Scope, DisplayName, Id, Url)                         # check site collection features in current web app             foreach($site in ($webApp.Sites))             {                 $results += ($site.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                                  % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $site.Url -PassThru} |                                  Select-Object -Property Scope, DisplayName, Id, Url)                                 # check site features in current site collection                 foreach($web in ($site.AllWebs))                 {                     $results += ($web.Features | Select-Object -ExpandProperty Definition | Where-Object {[string]::IsNullOrEmpty($Identity) -or ($_.DisplayName -eq $Identity)} |                                      % {Add-Member -InputObject $_ -MemberType noteproperty -Name Url -Value $web.Url -PassThru} |                                      Select-Object -Property Scope, DisplayName, Id, Url)                                                        $web.Dispose()                 }                 $site.Dispose()             }         }     }     End     {         $results     } } #end Get-SPFeatureActivated Get-SPFeatureActivated   Conclusion    I have posted this script to the TechNet Script Repository (click here).  As always I appreciate any feedback on scripts.  If anyone is motivated to run this 2007 version script against a SharePoint 2010 to see if they find any differences in number of features reported versus what they get with the 2010 version script I’d love to hear from you.         -Frog Out

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• Should I manage authentication on my own if the alternative is very low in usability and I am already managing roles?

  - by rumtscho

  As a small in-house dev department, we only have experience with developing applications for our intranet. We use the existing Active Directory for user account management. It contains the accounts of all company employees and many (but not all) of the business partners we have a cooperation with. Now, the top management wants a technology exchange application, and I am the lead dev on the new project. Basically, it is a database containing our know-how, with a web frontend. Our employees, our cooperating business partners, and people who wish to become our cooperating business partners should have access to it and see what technologies we have, so they can trade for them with the department which owns them. The technologies are not patented, but very valuable to competitors, so the department bosses are paranoid about somebody unauthorized gaining access to their technology description. This constraint necessitates a nightmarishly complicated multi-dimensional RBAC-hybrid model. As the Active Directory doesn't even contain all the information needed to infer the roles I use, I will have to manage roles plus per-technology per-user granted access exceptions within my system. The current plan is to use Active Directory for authentication. This will result in a multi-hour registration process for our business partners where the database owner has to manually create logins in our Active Directory and send them credentials. If I manage the logins in my own system, we could improve the usability a lot, for example by letting people have an active (but unprivileged) account as soon as they register. It seems to me that, after I am having a users table in the DB anyway (and managing ugly details like storing historical user IDs so that recycled user IDs within the Active Directory don't unexpectedly get rights to view someone's technologies), the additional complexity from implementing authentication functionality will be minimal. Therefore, I am starting to lean towards doing my own user login management and forgetting the AD altogether. On the other hand, I see some reasons to stay with Active Directory. First, the conventional wisdom I have heard from experienced programmers is to not do your own user management if you can avoid it. Second, we have code I can reuse for connection to the active directory, while I would have to code the authentication if done in-system (and my boss has clearly stated that getting the project delivered on time has much higher priority than delivering a system with high usability). Third, I am not a very experienced developer (this is my first lead position) and have never done user management before, so I am afraid that I am overlooking some important reasons to use the AD, or that I am underestimating the amount of work left to do my own authentication. I would like to know if there are more reasons to go with the AD authentication mechanism. Specifically, if I want to do my own authentication, what would I have to implement besides a secure connection for the login screen (which I would need anyway even if I am only transporting the pw to the AD), lookup of a password hash and a mechanism for password recovery (which will probably include manual identity verification, so no need for complex mTAN-like solutions)? And, if you have experience with such security-critical systems, which one would you use and why?

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• Approach for packing 2D shapes while minimizing total enclosing area

  - by Dennis

  Not sure on my tags for this question, but in short .... I need to solve a problem of packing industrial parts into crates while minimizing total containing area. These parts are motors, or pumps, or custom-made components, and they have quite unusual shapes. For some, it may be possible to assume that a part === rectangular cuboid, but some are not so simple, i.e. they assume a shape more of that of a hammer or letter T. With those, (assuming 2D shape), by alternating direction of top & bottom, one can pack more objects into the same space, than if all tops were in the same direction. Crude example below with letter "T"-shaped parts: ***** xxxxx ***** x ***** *** ooo * x vs * x vs * x vs * x o * x * xxxxx * x * x o xxxxx xxx Right now we are solving the problem by something like this: using CAD software, make actual models of how things fit in crate boxes make estimates of actual crate dimensions & write them into Excel file (1) is crazy amount of work and as the result we have just a limited amount of possible entries in (2), the Excel file. The good things is that programming this is relatively easy. Given a combination of products to go into crates, we do a lookup, and if entry exists in the Excel (or Database), we bring it out. If it doesn't, we say "sorry, no data!". I don't necessarily want to go full force on making up some crazy algorithm that given geometrical part description can align, rotate, and figure out best part packing into a crate, given its shape, but maybe I do.. Question Well, here is my question: assuming that I can represent my parts as 2D (to be determined how), and that some parts look like letter T, and some parts look like rectangles, which algorithm can I use to give me a good estimate on the dimensions of the encompassing area, while ensuring that the parts are packed in a minimal possible area, to minimize crating/shipping costs? Are there approximation algorithms? Seeing how this can get complex, is there an existing library I could use? My thought / Approach My naive approach would be to define a way to describe position of parts, and place the first part, compute total enclosing area & dimensions. Then place 2nd part in 0 degree orientation, repeat, place it at 180 degree orientation, repeat (for my case I don't think 90 degree rotations will be meaningful due to long lengths of parts). Proceed using brute force "tacking on" other parts to the enclosing area until all parts are processed. I may have to shift some parts a tad (see 3rd pictorial example above with letters T). This adds a layer of 2D complexity rather than 1D. I am not sure how to approach this. One idea I have is genetic algorithms, but I think those will take up too much processing power and time. I will need to look out for shape collisions, as well as adding extra padding space, since we are talking about real parts with irregularities rather than perfect imaginary blocks. I'm afraid this can get geometrically messy fairly fast, and I'd rather keep things simple, if I can. But what if the best (practical) solution is to pack things into different crate boxes rather than just one? This can get a bit more tricky. There is human element involved as well, i.e. like parts can go into same box and are thus a constraint to be considered. Some parts that are not the same are sometimes grouped together for shipping and can be considered as a common grouped item. Sometimes customers want things shipped their way, which adds human element to constraints. so there will have to be some customization.

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• SharePoint Content and Site Editing Tips

  - by Bil Simser

  A few content management and site editing tips for power users on this bacon flavoured unicorn morning. The theme here is keep it clean!Write "friendly" email addressesRemember it's human beings reading your content. So seeing something like "If you have questions please send an email to [email protected]" breaks up the readiblity. Instead just do the simple steps of writing the content in plain English and going back, highlighting the name and insert a link (note: you might have to prefix the link with mailto:[email protected]). It makes for a friendlier looking page and hides the ugliness that are sometimes in email addresses.Use friendly column and list namesThis is a big pet peeve of mine. When you first create a column or list with spaces the internal name is changed. The display name might be "My Amazing List of Animals with Large Testicles" but the internal (and link) name becomes "My_x00x20_Amazing_x00x20_List_x00x20_of_x00x20_Animals_x00x20_with_x00x20_Large_x00x20_Testicles". What's worse is if you create a publishing page named "This Website is Fueled By a Dolphin's Spleen". Not only is it incorrect grammar, but the apostrophe wreaks havoc on both the internal name for the list (with lots of crazy hex codes) as well as the hyperlink (where everything is uuencoded). Instead create the list with a distinct and compact name then go back and change it to whatever you want. The end result is a better formed name that you can both script and access in code easier.Keep your Views CleanWhen you add a column to a list or create a new list the default is to add it to the default view. Do everyone a favour and don't check this box! The default view of a list should be something similar to the Title field and nothing else. Keep it clean. If you want to set a defalt view that's different, go back and create one with all the fields and filtering and sorting columns you want and set it as default. It's a good idea to keep the original AllItems.aspx (note the lack of space in the filename!) easy and unfiltered. It's also a good idea to keep your column count down in views. Don't let every column be added by default and don't add every column just because you can. Create separate views for distinct responsibilities and try to keep the number of columns down to a single screen to prevent horizontal scrolling.Simple NavigationThe Quick Launch is a great tool for navigating around your site but don't use the default of adding all lists to it. Uncheck that box and keep navigation simple. Create custom groupings that make sense so if you don't have a site with "Documents and Lists" but "Reports and Notices" makes more sense then do it. Also hide internal lists from the Quick Launch. For example, if most users don't need to see all the lookup tables you might have on a site don't show them. You can use audience filtering on the Quick Launch if you want to hide admin items from non-admin users so consider that as an option.Enjoy!

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• What Counts For a DBA – Depth

  - by Louis Davidson

  SQL Server offers very simple interfaces to many of its features. Most people could open up SSMS, connect to a server, write a simple query and see the results. Even several of the core DBA tasks are deceptively straightforward. It doesn’t take a rocket scientist to perform a basic database backup or run a trace (even using the newfangled Extended Events!). However, appearances can be deceptive, and often times it is really important that a DBA understands not just the basics of how to perform a task, but why we do a task, and how that task works. As an analogy, consider a child walking into a darkened room. Most would know that they need to turn on the light, and how to do it, so they flick the switch. But what happens if light fails to shine forth. Most would immediately tell you that you need to consider changing the light bulb. So you hop in the car and take them to the local home store and instruct them to buy a replacement. Confronted with a 40 foot display of light bulbs, how will they decide which of the hundreds of types of bulbs, of different types, fittings, shapes, colors, power and efficiency ratings, is the right choice? Obviously the main lesson the child is going to learn this day is how to use their cell phone as a flashlight so they don’t have to ask for help the next time. Likewise, when the metaphorical toddlers who use your database server have issues, they will instinctively know something is wrong, and may even have some idea what caused it, but will have no depth of knowledge to figure out the right solution. That is where the DBA comes in and attempts to save the day. However, when one looks beneath the shiny UI, SQL Server has its own “40 foot display of light bulbs”, in the form of the tremendous number of tools and the often-bewildering amount of information they can present to the DBA, to help us find issues. Unfortunately, resorting to guesswork, to trying different “bulbs” over and over, hoping to stumble on the answer. This is where the right depth of knowledge goes a long way. If we need to write a SELECT statement, then knowing the syntax and where to find the data is not enough. Knowledge of indexes and query plans is essential. Without it, we might hit on a query that “works”, but we are basically still a user, not a programmer, because we have no real control over our platform. Is that level of knowledge deep enough? Probably not, since knowledge of the underlying metadata and structures would be very useful in helping us make sense of any query plan. Understanding the structure of an index makes the “key lookup” operator not sound like what you do when someone tapes your car key to the ceiling. So is even this level of understanding deep enough? Do we need to understand the memory architecture used to process the query? It might be a comforting level of knowledge, and will doubtless come in handy at some point, but is not strictly necessary in most cases. Beyond that lies (more or less) full knowledge of SQL language and the intricacies of every step the SQL Server engine takes to process our query. My personal theory is that, as a professional, our knowledge of a given task should extend, at a minimum, one level deeper than is strictly necessary to perform the task. Anything deeper can be left to the ridiculously smart, or obsessive, or both. As an example. tasked with storing an integer value between 0 and 99999999, it’s essential that I know that choosing an Integer over Decimal(8,0) will likely offer performance benefits. It is then useful that I also understand the value of adding a CHECK constraint, to make sure the values are valid to the desired range; and comforting that I know a little about the underlying processors, registers and computer math. Anything further, I leave to the likes of Joe Chang, whose recent blog post on the topic offers depth by the bucketful!  

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• Use a custom value object or a Guid as an entity identifier in a distributed system?

  - by Kazark

  tl;dr I've been told that in domain-driven design, an identifier for an entity could be a custom value object, i.e. something other than Guid, string, int, etc. Can this really be advisable in a distributed system? Long version I will invent an situation analogous to the one I am currently facing. Say I have a distributed system in which a central concept is an egg. The system allows you to order eggs and see spending reports and inventory-centric data such as quantity on hand, usage, valuation and what have you. There area variety of services backing these behaviors. And say there is also another app which allows you to compose recipes that link to a particular egg type. Now egg type is broken down by the species—ostrich, goose, duck, chicken, quail. This is fine and dandy because it means that users don't end up with ostrich eggs when they wanted quail eggs and whatnot. However, we've been getting complaints because jumbo chicken eggs are not even close to equivalent to small ones. The price is different, and they really aren't substitutable in recipes. And here we thought we were doing users a favor by not overwhelming them with too many options. Currently each of the services (say, OrderSubmitter, EggTypeDefiner, SpendingReportsGenerator, InventoryTracker, RecipeCreator, RecipeTracker, or whatever) are identifying egg types with an industry-standard integer representation the species (let's call it speciesCode). We realize we've goofed up because this change could effect every service. There are two basic proposed solutions: Use a predefined identifier type like Guid as the eggTypeID throughout all the services, but make EggTypeDefiner the only service that knows that this maps to a speciesCode and eggSizeCode (and potentially to an isOrganic flag in the future, or whatever). Use an EggTypeID value object which is a combination of speciesCode and eggSizeCode in every service. I've proposed the first solution because I'm hoping it better encapsulates the definition of what an egg type is in the EggTypeDefiner and will be more resilient to changes, say if some people now want to differentiate eggs by whether or not they are "organic". The second solution is being suggested by some people who understand DDD better than I do in the hopes that less enrichment and lookup will be necessary that way, with the justification that in DDD using a value object as an ID is fine. Also, they are saying that EggTypeDefiner is not a domain and EggType is not an entity and as such should not have a Guid for an ID. However, I'm not sure the second solution is viable. This "value object" is going to have to be serialized into JSON and URLs for GET requests and used with a variety of technologies (C#, JavaScript...) which breaks encapsulation and thus removes any behavior of the identifier value object (is either of the fields optional? etc.) Is this a case where we want to avoid something that would normally be fine in DDD because we are trying to do DDD in a distributed fashion? Summary Can it be a good idea to use a custom value object as an identifier in a distributed system (solution #2)?

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• How to handle multi-processing of libraries which already spawn sub-processes?

  - by exhuma

  I am having some trouble coming up with a good solution to limit sub-processes in a script which uses a multi-processed library and the script itself is also multi-processed. Both, the library and script are modifiable by us. I believe the question is more about design than actual code, but for what it's worth, it's written in Python. The goal of the library is to hide implementation details of various internet routers. For that reason, the library has a "Proxy" factory method which takes the IP of a router as parameter. The factory then probes the device using a set of possible proxies. Usually, there is one proxy which immediately knows that is is able to send commands to this device. All others usually take some time to return (given a timeout). One thought was already to simply query the device for an identifier, and then select the proper proxy using that, but in order to do so, you would already need to know how to query the device. Abstracting this knowledge is one of the main purposes of the library, so that becomes a little bit of a "circular-requirement"/deadlock: To connect to a device, you need to know what proxy to use, and to know what proxy to create, you need to connect to a device. So probing the device is - as we can see - the best solution so far, apart from keeping a lookup-table somewhere. The library currently kills all remaining processes once a valid proxy has been found. And yes, there is always only one good proxy per device. Currently there are about 12 proxies. So if one create a proxy instance using the factory, 12 sub-processes are spawned. So far, this has been really useful and worked very well. But recently someone else wanted to use this library to "broadcast" a command to all devices. So he took the library, and wrote his own multi-processed script. This obviously spawned 12 * n processes where n is the number of IPs to which he broadcasted. This has given us two problems: The host on which the command was executed slowed down to a near halt. Aborting the script with CTRL+C ground the system to a total halt. Not even the hardware console responded anymore! This may be due to some Python strangeness which still needs to be investigated. Maybe related to http://bugs.python.org/issue8296 The big underlying question, is how to design a library which does multi-processing, so other applications which use this library and want to be multi-processed themselves do not run into system limitations. My first thought was to require a pool to be passed to the library, and execute all tasks in that pool. In that way, the person using the library has control over the usage of system resources. But my gut tells me that there must be a better solution. Disclaimer: My experience with multiprocessing is fairly limited. I have implemented a few straightforward which did not require access control to resources. So I have not yet any practical experience with semaphores or mutexes. p.s.: In the future, we may have enough information to do this without the probing. But the database which would contain the proper information is not yet operational. Also, the design about multiprocessing a multiprocessed library intrigues me :)

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• Is this over-abstraction? (And is there a name for it?)

  - by mwhite

  I work on a large Django application that uses CouchDB as a database and couchdbkit for mapping CouchDB documents to objects in Python, similar to Django's default ORM. It has dozens of model classes and a hundred or two CouchDB views. The application allows users to register a "domain", which gives them a unique URL containing the domain name that gives them access to a project whose data has no overlap with the data of other domains. Each document that is part of a domain has its domain property set to that domain's name. As far as relationships between the documents go, all domains are effectively mutually exclusive subsets of the data, except for a few edge cases (some users can be members of more than one domain, and there are some administrative reports that include all domains, etc.). The code is full of explicit references to the domain name, and I'm wondering if it would be worth the added complexity to abstract this out. I'd also like to know if there's a name for the sort of bound property approach I'm taking here. Basically, I have something like this in mind: Before in models.py class User(Document): domain = StringProperty() class Group(Document): domain = StringProperty() name = StringProperty() user_ids = StringListProperty() # method that returns related document set def users(self): return [User.get(id) for id in self.user_ids] # method that queries a couch view optimized for a specific lookup @classmethod def by_name(cls, domain, name): # the view method is provided by couchdbkit and handles # wrapping json CouchDB results as Python objects, and # can take various parameters modifying behavior return cls.view('groups/by_name', key=[domain, name]) # method that creates a related document def get_new_user(self): user = User(domain=self.domain) user.save() self.user_ids.append(user._id) return user in views.py: from models import User, Group # there are tons of views like this, (request, domain, ...) def create_new_user_in_group(request, domain, group_name): group = Group.by_name(domain, group_name)[0] user = User(domain=domain) user.save() group.user_ids.append(user._id) group.save() in group/by_name/map.js: function (doc) { if (doc.doc_type == "Group") { emit([doc.domain, doc.name], null); } } After models.py class DomainDocument(Document): domain = StringProperty() @classmethod def domain_view(cls, *args, **kwargs): kwargs['key'] = [cls.domain.default] + kwargs['key'] return super(DomainDocument, cls).view(*args, **kwargs) @classmethod def get(cls, *args, **kwargs, validate_domain=True): ret = super(DomainDocument, cls).get(*args, **kwargs) if validate_domain and ret.domain != cls.domain.default: raise Exception() return ret def models(self): # a mapping of all models in the application. accessing one returns the equivalent of class BoundUser(User): domain = StringProperty(default=self.domain) class User(DomainDocument): pass class Group(DomainDocument): name = StringProperty() user_ids = StringListProperty() def users(self): return [self.models.User.get(id) for id in self.user_ids] @classmethod def by_name(cls, name): return cls.domain_view('groups/by_name', key=[name]) def get_new_user(self): user = self.models.User() user.save() views.py @domain_view # decorator that sets request.models to the same sort of object that is returned by DomainDocument.models and removes the domain argument from the URL router def create_new_user_in_group(request, group_name): group = request.models.Group.by_name(group_name) user = request.models.User() user.save() group.user_ids.append(user._id) group.save() (Might be better to leave the abstraction leaky here in order to avoid having to deal with a couchapp-style //! include of a wrapper for emit that prepends doc.domain to the key or some other similar solution.) function (doc) { if (doc.doc_type == "Group") { emit([doc.name], null); } } Pros and Cons So what are the pros and cons of this? Pros: DRYer prevents you from creating related documents but forgetting to set the domain. prevents you from accidentally writing a django view - couch view execution path that leads to a security breach doesn't prevent you from accessing underlying self.domain and normal Document.view() method potentially gets rid of the need for a lot of sanity checks verifying whether two documents whose domains we expect to be equal are. Cons: adds some complexity hides what's really happening requires no model modules to have classes with the same name, or you would need to add sub-attributes to self.models for modules. However, requiring project-wide unique class names for models should actually be fine because they correspond to the doc_type property couchdbkit uses to decide which class to instantiate them as, which should be unique. removes explicit dependency documentation (from group.models import Group)

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• Sharepoint Lists.GetListItems Method rowLimit problem

  - by Linda

  In SharePoint I am using the default view of a list. When I use GetListItems method I can pass into it the following: public XmlNode GetListItems ( string listName, string viewName, XmlNode query, XmlNode viewFields, string rowLimit, XmlNode queryOptions, string webID ) I am passing in "" for the viewName and am passing a rowLimit of 1000. By Default view only returns 100 items. 100 Items are still being returned not 1000. Can you use the rowLimit when not specifying a view? Is it possible to bring back 1000 items using the query instead? I do not really want to use a GUID for the viewName as I would have to look it up for each list and perform a big refactor. Update I am now using the guid of the view and my list still returns the incorrect number of items. I know the guid is being used as I sued an incorrect one and it errord out. Any ideas what could be wrong? The code that is being sent to the service is as follows: <GetListItems xmlns='http://schemas.microsoft.com/sharepoint/soap/'> <listName>Media Outlet</listName> <viewName>{2822F0D9-A905-44B5-8913-34E6497F1AAF}</viewName> <query><Query><Where><Eq><FieldRef Name='Outlet_x0020_Type' /><Value Type='Lookup'></Value></Eq></Where><OrderBy><FieldRef Name='Title' /></OrderBy></Query></query> <ViewFields></ViewFields> <RowLimit>10000</RowLimit> <QueryOptions></QueryOptions> <webID></webID> </GetListItems>

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• make_tuple with boost::python under Visual Studio 9

  - by celil

  Trying to build the following simple example #include <boost/python.hpp> using namespace boost::python; tuple head_and_tail(object sequence) { return make_tuple(sequence[0],sequence[-1]); } available here, I end up with this compilation error under Visual Studio 9 error C2668: 'boost::python::make_tuple' : ambiguous call to overloaded function 1> C:\Program Files\boost_1_42_0\boost/python/detail/make_tuple.hpp(22): could be 'boost::python::tuple boost::python::make_tuple<boost::python::api::object_item,boost::python::api::object_item>(const A0 &,const A1 &)' 1> with 1> [ 1> A0=boost::python::api::object_item, 1> A1=boost::python::api::object_item 1> ] 1> C:\Program Files\boost_1_42_0\boost/tuple/detail/tuple_basic.hpp(802): or 'boost::tuples::tuple<T0,T1,T2,T3,T4,T5,T6,T7,T8,T9> boost::tuples::make_tuple<boost::python::api::object_item,boost::python::api::object_item>(const T0 &,const T1 &)' [found using argument-dependent lookup] 1> with 1> [ 1> T0=boost::python::api::proxy<boost::python::api::item_policies>, 1> T1=boost::python::api::proxy<boost::python::api::item_policies>, 1> T2=boost::tuples::null_type, 1> T3=boost::tuples::null_type, 1> T4=boost::tuples::null_type, 1> T5=boost::tuples::null_type, 1> T6=boost::tuples::null_type, 1> T7=boost::tuples::null_type, 1> T8=boost::tuples::null_type, 1> T9=boost::tuples::null_type 1> ] Is this a bug in boost::python, or am I doing something wrong? How can I get the above program to compile?

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• Sharepoint GetListItems using rowLimit parameter is not limiting the results returned

  - by Linda

  In SharePoint I am using the default view of a list. When I use GetListItems method I can pass into it the following: public XmlNode GetListItems ( string listName, string viewName, XmlNode query, XmlNode viewFields, string rowLimit, XmlNode queryOptions, string webID ) I am passing in "" for the viewName and am passing a rowLimit of 1000. By Default view only returns 100 items. 100 Items are still being returned not 1000. Can you use the rowLimit when not specifying a view? Is it possible to bring back 1000 items using the query instead? I do not really want to use a GUID for the viewName as I would have to look it up for each list and perform a big refactor. Update I am now using the guid of the view and my list still returns the incorrect number of items. I know the guid is being used as I sued an incorrect one and it errord out. Any ideas what could be wrong? The code that is being sent to the service is as follows: <GetListItems xmlns='http://schemas.microsoft.com/sharepoint/soap/'> <listName>Media Outlet</listName> <viewName>{2822F0D9-A905-44B5-8913-34E6497F1AAF}</viewName> <query><Query><Where><Eq><FieldRef Name='Outlet_x0020_Type' /><Value Type='Lookup'></Value></Eq></Where><OrderBy><FieldRef Name='Title' /></OrderBy></Query></query> <ViewFields></ViewFields> <RowLimit>10000</RowLimit> <QueryOptions></QueryOptions> <webID></webID> </GetListItems>

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• How to validate xml using a .dtd via a proxy and NOT using system.net.defaultproxy

  - by Lanceomagnifico

  Hi, Someone else has already asked a somewhat similar question: http://stackoverflow.com/questions/1888887/validate-an-xml-file-against-a-dtd-with-a-proxy-c-2-0/2766197#2766197 Here's my problem: We have a website application that needs to use both internal and external resources. We have a bunch of internal webservices. Requests to the CANNOT go through the proxy. If we try to, we get 404 errors since the proxy DNS doesn't know about our internal webservice domains. We generate a few xml files that have to be valid. I'd like to use the provided dtd documents to validate the xml. The dtd urls are outside our network and MUST go through the proxy. Is there any way to validate via dtd through a proxy without using system.net.defaultproxy? If we use defaultproxy, the internal webservices are busted, but the dtd validation works.# Here is what I'm doing to validate the xml right now: public static XDocument ValidateXmlUsingDtd(string xml) { var xrSettings = new XmlReaderSettings { ValidationType = ValidationType.DTD, ProhibitDtd = false }; var sr = new StringReader(xml.Trim()); XmlReader xRead = XmlReader.Create(sr, xrSettings); return XDocument.Load(xRead); } Ideally, there would be some way to assign a proxy to the XmlReader much like you can assign a proxy to the HttpWebRequest object. Or perhaps there is a way to programatically turn defaultproxy on or off? So that I can just turn it on for the call to Load the Xdocument, then turn it off again? FYI - I'm open to ideas on how to tackle this - note that the proxy is located in another domain, and they don't want to have to set up a dns lookup to our dns server for our internal webservice addresses. Cheers, Lance

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• How to handle corrupt messages arriving on a socket?

  - by Pieter

  I've got a working socket handling mechanism, similar (but a bit more complex) to Qt's Fortune Example http://qt.nokia.com/doc/4.5/network-fortuneclient.html http://qt.nokia.com/doc/4.5/network-fortuneserver.html Now I'm wondering how to handle corrupt messages. Discarding the data is a start, but I need to discard up to a point I can start processing messages again. The corrupt message may be lost, but I need to be able to recover from it. I've got the following idea in mind: Put a fixed header at the start of each message, eg. 0xABCDEF01. When recovering, lookup this header and restart handling incoming messages. = Break off readFortune() on a timeout and recover = When encountering an inconsistent header, recover A huge blocksize is still going to be a problem. To fix that, I should be constantly checking whether or not I'm reading gibberish, but this is not always possible. I can also limit the blocksize on certain message-types. Any ideas on this? Any proposals on what to use as byteword?

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• [Linq to SQL] Multiple foreign keys to the same table

  - by cdonner

  I have a reference table with all sorts of controlled value lookup data for gender, address type, contact type, etc. Many tables have multiple foreign keys to this reference table I also have many-to-many association tables that have two foreign keys to the same table. Unfortunately, when these tables are pulled into a Linq model and the DBML is generated, SQLMetal does not look at the names of the foreign key columns, or the names of the constraints, but only at the target table. So I end up with members called Reference1, Reference2, ... not very maintenance-friendly. Example: <Association Name="tb_reference_tb_account" Member="tb_reference" <====== ThisKey="shipping_preference_type_id" OtherKey="id" Type="tb_reference" IsForeignKey="true" /> <Association Name="tb_reference_tb_account1" Member="tb_reference1" <====== ThisKey="status_type_id" OtherKey="id" Type="tb_reference" IsForeignKey="true" /> I can go into the DBML and manually change the member names, of course, but this would mean I can no longer round-trip my database schema. This is not an option at the current stage of the model, which is still evolving. Splitting the reference table into n individual tables is also not desirable. I can probably write a script that runs against the XML after each generation and replaces the member name with something derived from ThisKey (since I adhere to a naming convention for these types of keys). Has anybody found a better solution to this problem?

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• SQL MIN in Sub query causes huge delay

  - by Spencer

  I have a SQL query that I'm trying to debug. It works fine for small sets of data, but in large sets of data, this particular part of it causes it to take 45-50 seconds instead of being sub second in speed. This subquery is one of the select items in a larger query. I'm basically trying to figure out when the earliest work date is that fits in the same category as the current row we are looking at (from table dr) ISNULL(CONVERT(varchar(25),(SELECT MIN(drsd.DateWorked) FROM [TableName] drsd WHERE drsd.UserID = dr.UserID AND drsd.Val1 = dr.Val1 OR (((drsd.Val2 = dr.Val2 AND LEN(dr.Val2) > 0) AND (drsd.Val3 = dr.Val3 AND LEN(dr.Val3) > 0) AND (drsd.Val4 = dr.Val4 AND LEN(dr.Val4) > 0)) OR (drsd.Val5 = dr.Val5 AND LEN(dr.Val5) > 0) OR ((drsd.Val6 = dr.Val6 AND LEN(dr.Val6) > 0) AND (drsd.Val7 = dr.Val7 AND LEN(dr.Val2) > 0))))), '') AS WorkStartDate, This winds up executing a key lookup some 18 million times on a table that has 346,000 records. I've tried creating an index on it, but haven't had any success. Also, selecting a max value in this same query is sub second in time, as it doesn't have to execute very many times at all. Any suggestions of a different approach to try? Thanks!

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• Anyone have BlazeDS working with WebLogic Security (j_security_check) ??

  - by Brian

  I'm working on a Flex implementation (currently using SDK 3.5) on WebLogic 10.3 (11G.) We originally used Glassfish v2.1.1 with zero issues (there was an active directory group lookup bug but it did not hinder our progress.) Since transitioning to WebLogic we have an issue where the flexsession is invalidated after logging in using j_security_check: [BlazeDS]Unexpected error encountered in Message Broker servlet flex.messaging.LocalizedException: The FlexSession is invalid. at flex.messaging.FlexSession.checkValid(FlexSession.java:943) at flex.messaging.FlexSession.getUserPrincipal(FlexSession.java:254) at flex.messaging.HttpFlexSession.getUserPrincipal(HttpFlexSession.java:286) at flex.messaging.MessageBrokerServlet.service(MessageBrokerServlet.java:296) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:292) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175) at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3594) at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321) at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:121) at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2202) at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2108) at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1432) at weblogic.work.ExecuteThread.execute(ExecuteThread.java:201) at weblogic.work.ExecuteThread.run(ExecuteThread.java:173) I've tried almost every option in services-config.xml: [security [login-command class="flex.messaging.security.WeblogicLoginCommand" server="Weblogic"/> [!-- Uncomment the correct app server [login-command class="flex.messaging.security.TomcatLoginCommand" server="JBoss"> [login-command class="flex.messaging.security.JRunLoginCommand" server="JRun"/> [login-command class="flex.messaging.security.TomcatLoginCommand" server="Tomcat"/> [login-command class="flex.messaging.security.WebSphereLoginCommand" server="WebSphere"/> --> [/security> I've even completely removed this section with no luck. The login functions correctly from a non-BlazeDS perspective. It authenticates the user correctly. Without authentication, BlazeDS works fine (no errors for any remote calls.) Together its a big ball of fail (invalid flexsession every time.) Has anyone got this working? Any tips?

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• JEE6 Global JNDI Name and Maven Deployment

  - by wobblycogs

  I'm having some problems with the global JNDI names of my EJB resources which is (or at least will) cause my JNDI look ups to fail. The project is being developed on Netbeans and is a standard Maven Web Application. When my application is deployed to GF3.0 the application name is set to something like: com.example_myapp_war_1.0-SNAPSHOT which is all well and good from Netbeans point of view because it ensures the name is unique but it also means all the EJBs get global names such as this: java:global/com.example_myapp_war_1.0-SNAPSHOT/CustomerService This, of course, is going to cause problems because every time the version changes all the global names change (I've tested this by changing the version and the names indeed changed). The name is being generated from the POM file and it's a concatenation of: <groupId>com.example</groupId> <artifactId>myapp</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> Up until now I've got away with just injecting all the resources using @EJB but now I need to access the CustomerService EJB from a JSF Converter so I'm doing a JNDI look up like this: try { Context ctx = new InitialContext(); CustomerService customerService = (CustomerService)ctx.lookup( "java:global/com.example_myapp_war_1.0-SNAPSHOT/CustomerService" ); return customerService.get(submittedValue); } catch( Exception e ) { logger.error( "Failed to convert customer.", e ); return null; } which will clearly break when the application is properly released and the module name changes. So, the million dollar question: how can I set the modle name in maven or how do I recover the module name so that I can programatically build the JNDI name at runtile. I've tried setting it in the web.xml file as suggested by that link but it was ignored. I think I'd rather build the name at runtime as that means there is less scope for screw ups when the application is deployed. Many thanks for any help, I've been tearing my hair out all day on this.

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• Static factory pattern with EJB3/JBoss

  - by purecharger

  I'm fairly new to EJBs and full blown application servers like JBoss, having written and worked with special purpose standalone Java applications for most of my career, with limited use of JEE. I'm wondering about the best way to adapt a commonly used design pattern to EJB3 and JBoss: the static factory pattern. In fact this is Item #1 in Joshua Bloch's Effective Java book (2nd edition) I'm currently working with the following factory: public class CredentialsProcessorFactory { private static final Log log = LogFactory.getLog(CredentialsProcessorFactory.class); private static Map<CredentialsType, CredentialsProcessor> PROCESSORS = new HashMap<CredentialsType, CredentialsProcessor>(); static { PROCESSORS.put(CredentialsType.CSV, new CSVCredentialsProcessor()); } private CredentialsProcessorFactory() {} public static CredentialsProcessor getProcessor(CredentialsType type) { CredentialsProcessor p = PROCESSORS.get(type); if(p == null) throw new IllegalArgumentException("No CredentialsProcessor registered for type " + type.toString()); return p; } However, in the implementation classes of CredentialsProcessor, I require injected resources such as a PersistenceContext, so I have made the CredentialsProcessor interface a @Local interface, and each of the impl's marked with @Stateless. Now I can look them up in JNDI and use the injected resources. But now I have a disconnect because I am not using the factory anymore. My first thought was to change the getProcessor(CredentialsType) method to do a JNDI lookup and return the SLSB instance that is required, but then I need to configure and pass the proper qualified JNDI name. Before I go down that path, I wanted to do more research on accepted practices. How is this design pattern treated in EJB3 / JEE?

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• TypeConverter prevents ApplyPropertyChanges in EntityFramework

  - by Felix

  I ran into an interesting problem (hopefully, interesting not just for me :) I am running Entity Framework 1 (.NET 3.5) and ASP.NET MVC 2. I have a Customer class that has many-to-one relationship with Country class (in other words, Country is a lookup table for customers - I described more in this post: http://stackoverflow.com/questions/2404801/explicit-casting-doesnt-work-in-default-model-binding ) I got TypeConverter to work; so I am getting a perfect object into controller's Post method. Create works fine; however, in Edit I am getting the following error when I call ApplyPropertyChanges: The existing object in the ObjectContext is in the Added state. Changes can only be applied when the existing object is in an unchanged or modified state. The controller code is fairly trivial: public ActionResult Edit(Customer customerToEdit) { if (ModelState.IsValid) { Customer cust = (Customer)context.GetObjectByKey( new EntityKey("BAEntities.Customers", "CustomerID", customerToEdit.CustomerID)); context.ApplyPropertyChanges(cust.EntityKey.EntitySetName, customerToEdit); context.SaveChanges(); } return View(...); } If I remove country from the form, it works fine; and if I assign dropdown value to EntityReference "manually" - it works as well. TypeConverter code is also fairly simple, but I've never used TypeConverter before, so I may be missing something here: public override object ConvertFrom(ITypeDescriptorContext typeContext, CultureInfo culture, object value) { if (value is string) { int countryID = Int16.Parse((string)value); Country country = (Country)context.GetObjectByKey( new EntityKey("BAEntities.Countries", "CountryID", countryID)); return country; } return base.ConvertFrom(typeContext, culture, value); }

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• Trouble understanding SSL certificate chain verification

  - by Josh K

  My app uses SSL to communicate securely with a server and it's having trouble verifying the certificate chain. The chain looks like this: Entrust.net Secure Server Certification Authority - DigiCert Global CA - *.ourdomain.com We are using a certificate store pulled from Mozilla. It contains the Entrust.net certificate, but not the DigiCert Global CA one. My understanding is that an intermediate authority doesn't have to be trusted as long as the root authority is, but the verification fails: % openssl verify -CAfile mozilla-root-certs.crt ourdomain.com.crt error 20 at 0 depth lookup:unable to get local issuer certificate So do I need to explicitly trust the DigiCert Global CA in order for verification to pass? That seems wrong. But you tell me! EDIT: I now understand that the certificate file needs to be available to OpenSSL up front. Something like this works: % openssl verify -CAfile mozilla-root-certs.crt -untrusted digicert.crt ourdomain.com.crt ourdomain.com.crt: OK This allows me to provide a copy of the DigiCert CA without explicitly saying "I trust it", the whole chain still needs to be verified. But surely browsers like Firefox won't always ship with a copy of every single certificate it'll ever need. There's always going to be new CAs and the point is to use the security of the root certificate to make sure all intermediate CAs are valid. Right? So how does this work? Is it really as silly as it looks?

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• ClassCastException When Calling an EJB that Exists on Same Server

  - by aaronvargas

  I have 2 ejbs. Ejb-A that calls Ejb-B. They are not in the same Ear. For portability Ejb-B may or may not exist on the same server. (There is an external property file that has the provider URLs of Ejb-B. I have no control over this.) Example Code: in Ejb-A EjbBDelegate delegateB = EjbBDelegateHelper.getRemoteDelegate(); // lookup from list of URLs from props... BookOfMagic bom = delegateB.getSomethingInteresting(); Use Cases/Outcomes: When Ejb-B DOES NOT EXIST on the same server as Ejb-A, everything works correctly. (it round-robbins through the URLs) When Ejb-B DOES EXIST on the same server, and Ejb-A happens to call Ejb-B on the same server, everything works correctly. When Ejb-B DOES EXIST on the same server, and Ejb-A calls Ejb-B on a different server, I get: javax.ejb.EJBException: nested exception is: java.lang.ClassCastException: $Proxy126 java.lang.ClassCastException: $Proxy126 NOTE (not normal use case but may help): When Ejb-B DOES EXIST on the same server, and this server is NOT listed in the provider URLs for Ejb-B, and Ejb-A calls Ejb-B on a different server, I get the same Exception as above. I'm using Weblogic 10.0, Java 5, EJB3 Basically, if Ejb-B Exists on the server, it must be called ONLY on that server. Which leads me to believe that the class is getting loaded by a local classloader (on deployment?), then when called remotely, a different classloader is loading it. (causing the Exception) But it should work, as it should be Serialized into the destination classloader... What am I doing wrong?? Also, when reproducing this locally, Ejb-A would favor the Ejb-B on the same server, so it was difficult to reproduce. But this wasn't the case on other machines.

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• java.lang.ClassCastException: $Proxy99 cannot be cast

  - by svaret

  Hi, I am using JBoss4.2.2 and java6. The deployed ear's name is apa.ear In a servlet I have the following code line: placeBid = (PlaceBid) context.lookup("apa/" + PlaceBid.class.getSimpleName() + "/remote"); I have a generated jboss-app.xml like this: <jboss-app> <loader-repository>apa:app=ejb3</loader-repository> </jboss-app> When trying to get the PlaceBid via the context I get this exception java.lang.ClassCastException: $Proxy99 cannot be cast to se.nextit.actionbazaar.buslogic.PlaceBid The PlaceBid interface looks like this: @Remote public interface PlaceBid { Long addBid(String userId, Long itemId, Double bidPrice); } When I run the example coming with EJB3 in action it works. EJB3 in action sample code comes with ant building. I want to use Maven so I have rearranged the code some. However, I don't understan what I am doing wrong here. I have some thoughts about the jboss-app.xml file. I am not sure of how its content should look like. Grateful for any help. Best wishes Lasse

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• RMI on client side generating exception when getting a reference to the RMI server

  - by Noona

  When I try to run an RMI client after running the RMI server I get the following exception: EncodeInterface exception: java.lang.ClassCastException: $Proxy30 cannot be cast to hw2.chat.backend.main.EncodeInterface java.lang.ClassCastException: $Proxy30 cannot be cast to hw2.chat.backend.main.EncodeInterface at hw2.chat.backend.main.EncodingRmiClient.initialiseRMIClient(EncodingRmiClient.java:26) And the relevant code in the RMI client is: EncodeInterface encodeInterface; Registry registry = LocateRegistry.getRegistry(host, portNumber); encodeInterface = (EncodeInterface)registry.lookup("RmiEncodingServer"); //line 26 And in the RMI server: try { EncodeInterface encodeInterface = new EncoderImpl(); Registry registry = LocateRegistry.getRegistry(); registry.rebind("RmiEncodingServer", encodeInterface); System.out.println("RmiEncodingServer is running..."); } EncodeInterface is the interface that extends Remote and that is present in the client side too. Host is "127.0.0.1" and portNumber is 1099 (I am assuming it should be the default value which is 1099 since I didn't specify it when I ran my RmiEncodingServer). If I don’t run the RMI server I get the same exception, any ideas as to why this is happening? thanks

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