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  • Separation of domain and ui layer in a composite

    - by hansmaad
    Hi all, i'm wondering if there is a pattern how to separate the domain logic of a class from the ui responsibilities of the objects in the domain layer. Example: // Domain classes interface MachinePart { CalculateX(in, out) // Where do we put these: // Draw(Screen) ?? // ShowProperties(View) ?? // ... } class Assembly : MachinePart { CalculateX(in, out) subParts } class Pipe : MachinePart { CalculateX(in, out) length, diamater... } There is an application that calculates the value X for machines assembled from many machine parts. The assembly is loaded from a file representation and is designed as a composite. Each concrete part class stores some data to implement the CalculateX(in,out) method to simulate behaviour of the whole assembly. The application runs well but without GUI. To increase the usability a GUi should be developed on top of the existing implementation (changes to the existing code are allowed). The GUI should show a schematic graphical representation of the assembly and provide part specific dialogs to edit several parameters. To achieve these goals the application needs new functionality for each machine part to draw a schematic representation on the screen, show a property dialog and other things not related to the domain of machine simulation. I can think of some different solutions to implement a Draw(Screen) functionality for each part but i am not happy with each of them. First i could add a Draw(Screen) method to the MachinePart interface but this would mix-up domain code with ui code and i had to add a lot of functionality to each machine part class what makes my domain model hard to read and hard to understand. Another "simple" solution is to make all parts visitable and implement ui code in visitors but Visitor does not belong to my favorite patterns. I could derive UI variants from each machine part class to add the UI implementation there but i had to check if each part class is suited for inheritance and had to be careful on changes to the base classes. My currently favorite design is to create a parallel composite hierarchy where each component stores data to define a machine part, has implementation for UI methods and a factory method which creates instances of the corresponding domain classes, so that i can "convert" a UI assembly to a domain assembly. But there are problems to go back from the created domain hierarchy to the UI hierarchy for showing calculation results in the drawing for example (imagine some parts store some values during the calculation i want to show in the schematic representation after the simluation). Maybe there are some proven patterns for such problems?

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  • How to get a stable, snappy UI using threads?

    - by Thomas Ahle
    I recently watching this video on Google Chrome with great interest. It explains that Google Chrome uses one thread for IO, one for opening files and one for intermodule communication. I think I may be able to use something similar for my own - currently quite messy - application. I wondered if there were any good articles on best-practices or patterns for such threaded divisions of tasks?

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  • Data access layer using Linq to SQL

    - by Andrei Tanasescu
    I am building a c# - linq - sql server winforms/asp.net application, accessing a database. I would like my business logic layer to be easily testable, and that means not littering it with Linq database queries everywhere. What design patterns/ best practices are available for the following use cases - inserting/updating a new object - searching for an object - loading a bunch of related data into a sort of "presentation" object that could be displayed by various views ?

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  • Table in DB for generating primary keys?

    - by Sapphire
    Do you ever use a separate table for "generating" artificial primary keys for DB (and why)? What I mean is to have a table with two columns, table name and current ID - with which you could get new "ID" for some table by simply locking the row with that table name, getting the current value of the key, increment it by one, and unlock the row. Why would you prefer this over standard integer identity column? P.S. The "idea" is from Fowlers Patterns of Enterprise Application Architecture, btw...

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  • How should I lay-out my PHP login class?

    - by ThinkingInBits
    So, there is going to be one login form; however 1 of 3 types of members will be signing in member_type_a, member_type_b, member_type_c all of whom have some of the same properties, and some whom may have specific methods and/or properties to them. I want the class to be saved to a session variable for use with member area pages. Any suggestions on applicable design patterns?

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  • What Design Pattern is this?

    - by 01
    I know that everything we do in programming can be described as design pattern(even abstract method has design pattern called template method) public class Guicer extends AbstractModule { private static Injector injector = Guice.createInjector(new Guicer()); public static void setInjector(Injector injector) { Guicer.injector = injector; } public static T getInstance(Class c) { return injector.getInstance(c); } @Override protected void configure() { } } What design patterns are used in this code?

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  • PHP Plugin based App design

    - by Aviatrix
    Hello , I was wondering from where i can get more info on how to build plugin based Apps (design patterns , etc ). Any books and references with detailed information would be helpful. Also i like how WordpPress was made , if someone can point me on how to build something like WordpPress did would be awesome. Thanks !

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  • I'm still learning OOP. Any tips on staying unbiased and pragmatic?

    - by marcdev
    I keep reading about defficiencies and issues with languages. Specifically, I'm learning PHP and Javascript, but I see it everywhere. This question arose while reading Javascript: The Good Parts and PHP Objects, Patterns and Practice. While understanding and avoiding easy pitfalls, is there a way I can learn the fundamentals of OOP and discover solid programming practices without overlooking important areas (or simply becoming jaded)? I'm sure I'll have plenty of opportunity to learn from mistakes!

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  • BPA scan did not complete for one or more servers

    - by Hossein Aarabi
    In Windows Server 2012 RTM, I am trying to run the BPA. It fails, saying "BPA scan did not complete for one or more servers" Try #1: Try #2: So, I decided to enable the Turn on Script Execution (with Allow all scripts) in Local Group Policy Editor, now I get a very nice exception message :) Clicking on ignore button, BPA logs the following error message: Try #3: So, I decided to go ahead and set the execution policy for all the scopes in PowerShell to unrestricted. Again no luck. What is going on?

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  • FreeBSD performance tuning. Sysctls, loader.conf, kernel.

    - by SaveTheRbtz
    I wanted to share knowledge of tuning FreeBSD via sysctls, so i'm posting them with comments. Based on Igor Sysoev (author of nginx) presentation about FreeBSD tuning up to 100,000-200,000 active connections. Sysctls are for 7.x FreeBSD. Since 7.2 amd64 some of them are tuned well by default. Prior 7.0 some of them are boot only (set via /boot/loader.conf) or does not exist at all. Highload web server sysctls: # Max. backlog size kern.ipc.somaxconn=4096 # Shared memory // 7.2+ can use shared memory > 2Gb kern.ipc.shmmax=2147483648 # Sockets kern.ipc.maxsockets=204800 # Do not use lager sockbufs on 8.0 # ( http://old.nabble.com/Significant-performance-regression-for-increased-maxsockbuf-on-8.0-RELEASE-tt26745981.html#a26745981 ) kern.ipc.maxsockbuf=262144 # Recive clusters (on amd64 7.2+ 65k is default) # For such high value vm.kmem_size must be increased to 3G #kern.ipc.nmbclusters=229376 # Jumbo pagesize(4k/8k) clusters # Used as general packet storage for jumbo frames # can be monitored via `netstat -m` #kern.ipc.nmbjumbop=192000 # Jumbo 9k/16k clusters # If you are using them #kern.ipc.nmbjumbo9=24000 #kern.ipc.nmbjumbo16=10240 # Every socket is a file, so increase them kern.maxfiles=204800 kern.maxfilesperproc=200000 kern.maxvnodes=200000 # Turn off receive autotuning #net.inet.tcp.recvbuf_auto=0 # Small receive space, only usable on http-server, on file server this # should be increased to 65535 or even more #net.inet.tcp.recvspace=8192 # Small send space is useful for http servers that serve small files # Autotuned since 7.x net.inet.tcp.sendspace=16384 # This should be enabled if you going to use big spaces (>64k) #net.inet.tcp.rfc1323=1 # Turn this off on highspeed, lossless connections (LAN 1Gbit+) #net.inet.tcp.delayed_ack=0 # This feature is useful if you are serving data over modems, Gigabit Ethernet, # or even high speed WAN links (or any other link with a high bandwidth delay product), # especially if you are also using window scaling or have configured a large send window. # You can try setting it to 0 on fileserver with 1GBit+ interfaces # Automatically disables on small RTT ( http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_subr.c?#rev1.237 ) #net.inet.tcp.inflight.enable=0 # Disable randomizing of ports to avoid false RST # Before usage check SA here www.bsdcan.org/2006/papers/ImprovingTCPIP.pdf # (it's also says that port randomization auto-disables at some conn.rates, but I didn't tested it thou) #net.inet.ip.portrange.randomized=0 # Increase portrange # For outgoing connections only. Good for seed-boxes and ftp servers. net.inet.ip.portrange.first=1024 net.inet.ip.portrange.last=65535 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Increases default TTL, sometimes useful # Default is 64 net.inet.ip.ttl=128 # Lessen max segment life to conserve resources # ACK waiting time in miliseconds (default: 30000 from RFC) net.inet.tcp.msl=5000 # Max bumber of timewait sockets net.inet.tcp.maxtcptw=40960 # Don't use tw on local connections # As of 15 Apr 2009. Igor Sysoev says that nolocaltimewait has some buggy realization. # So disable it or now till get fixed #net.inet.tcp.nolocaltimewait=1 # FIN_WAIT_2 state fast recycle net.inet.tcp.fast_finwait2_recycle=1 # Time before tcp keepalive probe is sent # default is 2 hours (7200000) #net.inet.tcp.keepidle=60000 # Should be increased until net.inet.ip.intr_queue_drops is zero net.inet.ip.intr_queue_maxlen=4096 # Interrupt handling via multiple CPU, but with context switch. # You can play with it. Default is 1; #net.isr.direct=0 # This is for routers only #net.inet.ip.forwarding=1 #net.inet.ip.fastforwarding=1 # This speed ups dummynet when channel isn't saturated net.inet.ip.dummynet.io_fast=1 # Increase dummynet(4) hash #net.inet.ip.dummynet.hash_size=2048 #net.inet.ip.dummynet.max_chain_len # Should be increased when you have A LOT of files on server # (Increase until vfs.ufs.dirhash_mem becames lower) vfs.ufs.dirhash_maxmem=67108864 # Explicit Congestion Notification (see http://en.wikipedia.org/wiki/Explicit_Congestion_Notification) net.inet.tcp.ecn.enable=1 # Flowtable - flow caching mechanism # Useful for routers #net.inet.flowtable.enable=1 #net.inet.flowtable.nmbflows=65535 # Extreme polling tuning #kern.polling.burst_max=1000 #kern.polling.each_burst=1000 #kern.polling.reg_frac=100 #kern.polling.user_frac=1 #kern.polling.idle_poll=0 # IPFW dynamic rules and timeouts tuning # Increase dyn_buckets till net.inet.ip.fw.curr_dyn_buckets is lower net.inet.ip.fw.dyn_buckets=65536 net.inet.ip.fw.dyn_max=65536 net.inet.ip.fw.dyn_ack_lifetime=120 net.inet.ip.fw.dyn_syn_lifetime=10 net.inet.ip.fw.dyn_fin_lifetime=2 net.inet.ip.fw.dyn_short_lifetime=10 # Make packets pass firewall only once when using dummynet # i.e. packets going thru pipe are passing out from firewall with accept #net.inet.ip.fw.one_pass=1 # shm_use_phys Wires all shared pages, making them unswappable # Use this to lessen Virtual Memory Manager's work when using Shared Mem. # Useful for databases #kern.ipc.shm_use_phys=1 /boot/loader.conf: # Accept filters for data, http and DNS requests # Usefull when your software uses select() instead of kevent/kqueue or when you under DDoS # DNS accf available on 8.0+ accf_data_load="YES" accf_http_load="YES" accf_dns_load="YES" # Async IO system calls aio_load="YES" # Adds NCQ support in FreeBSD # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ # 8.0+ only #ahci_load= #siis_load= # Increase kernel memory size to 3G. # # Use ONLY if you have KVA_PAGES in kernel configuration, and you have more than 3G RAM # Otherwise panic will happen on next reboot! # # It's required for high buffer sizes: kern.ipc.nmbjumbop, kern.ipc.nmbclusters, etc # Useful on highload stateful firewalls, proxies or ZFS fileservers # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #vm.kmem_size="3G" # Older versions of FreeBSD can't tune maxfiles on the fly #kern.maxfiles="200000" # Useful for databases # Sets maximum data size to 1G # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #kern.maxdsiz="1G" # Maximum buffer size(vfs.maxbufspace) # You can check current one via vfs.bufspace # Should be lowered/upped depending on server's load-type # Usually decreased to preserve kmem # (default is 200M) #kern.maxbcache="512M" # Sendfile buffers # For i386 only #kern.ipc.nsfbufs=10240 # syncache Hash table tuning net.inet.tcp.syncache.hashsize=1024 net.inet.tcp.syncache.bucketlimit=100 # Incresed hostcache net.inet.tcp.hostcache.hashsize="16384" net.inet.tcp.hostcache.bucketlimit="100" # TCP control-block Hash table tuning net.inet.tcp.tcbhashsize=4096 # Enable superpages, for 7.2+ only # Also read http://lists.freebsd.org/pipermail/freebsd-hackers/2009-November/030094.html vm.pmap.pg_ps_enabled=1 # Usefull if you are using Intel-Gigabit NIC #hw.em.rxd=4096 #hw.em.txd=4096 #hw.em.rx_process_limit="-1" # Also if you have ALOT interrupts on NIC - play with following parameters # NOTE: You should set them for every NIC #dev.em.0.rx_int_delay: 250 #dev.em.0.tx_int_delay: 250 #dev.em.0.rx_abs_int_delay: 250 #dev.em.0.tx_abs_int_delay: 250 # There is also multithreaded version of em drivers can be found here: # http://people.yandex-team.ru/~wawa/ # # for additional em monitoring and statistics use # `sysctl dev.em.0.stats=1 ; dmesg` # #Same tunings for igb #hw.igb.rxd=4096 #hw.igb.txd=4096 #hw.igb.rx_process_limit=100 # Some useful netisr tunables. See sysctl net.isr #net.isr.defaultqlimit=4096 #net.isr.maxqlimit: 10240 # Bind netisr threads to CPUs #net.isr.bindthreads=1 # Nicer boot logo =) loader_logo="beastie" And finally here is my additions to GENERIC kernel # Just some of them, see also # cat /sys/{i386,amd64,}/conf/NOTES # This one useful only on i386 #options KVA_PAGES=512 # You can play with HZ in environments with high interrupt rate (default is 1000) # 100 is for my notebook to prolong it's battery life #options HZ=100 # Polling is goot on network loads with high packet rates and low-end NICs # NB! Do not enable it if you want more than one netisr thread #options DEVICE_POLLING # Eliminate datacopy on socket read-write # To take advantage with zero copy sockets you should have an MTU of 8K(amd64) # (4k for i386). This req. is only for receiving data. # Read more in man zero_copy_sockets #options ZERO_COPY_SOCKETS # Support TCP sign. Used for IPSec options TCP_SIGNATURE options IPSEC # This ones can be loaded as modules. They described in loader.conf section #options ACCEPT_FILTER_DATA #options ACCEPT_FILTER_HTTP # Adding ipfw, also can be loaded as modules options IPFIREWALL options IPFIREWALL_VERBOSE options IPFIREWALL_VERBOSE_LIMIT=10 options IPFIREWALL_DEFAULT_TO_ACCEPT options IPFIREWALL_FORWARD # Adding kernel NAT options IPFIREWALL_NAT options LIBALIAS # Traffic shaping options DUMMYNET # Divert, i.e. for userspace NAT options IPDIVERT # This is for OpenBSD's pf firewall device pf device pflog # pf's QoS - ALTQ options ALTQ options ALTQ_CBQ # Class Bases Queuing (CBQ) options ALTQ_RED # Random Early Detection (RED) options ALTQ_RIO # RED In/Out options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC) options ALTQ_PRIQ # Priority Queuing (PRIQ) options ALTQ_NOPCC # Required for SMP build # Pretty console # Manual can be found here http://forums.freebsd.org/showthread.php?t=6134 #options VESA #options SC_PIXEL_MODE # Disable reboot on Ctrl Alt Del #options SC_DISABLE_REBOOT # Change normal|kernel messages color options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_KERNEL_CONS_ATTR=(FG_YELLOW|BG_BLACK) # More scroll space options SC_HISTORY_SIZE=8192 # Adding hardware crypto device device crypto device cryptodev # Useful network interfaces device vlan device tap #Virtual Ethernet driver device gre #IP over IP tunneling device if_bridge #Bridge interface device pfsync #synchronization interface for PF device carp #Common Address Redundancy Protocol device enc #IPsec interface device lagg #Link aggregation interface device stf #IPv4-IPv6 port # Also for my notebook, but may be used with Opteron #device amdtemp # Support for ECMP. More than one route for destination # Works even with default route so one can use it as LB for two ISP # For now code is unstable and panics (panic: rtfree 2) on route deletions. #options RADIX_MPATH # Multicast routing #options MROUTING #options PIM # DTrace options KDTRACE_HOOKS # all architectures - enable general DTrace hooks options DDB_CTF # all architectures - kernel ELF linker loads CTF data #options KDTRACE_FRAME # amd64-only # Adaptive spining in lockmgr (8.x+) # See http://www.mail-archive.com/[email protected]/msg10782.html options ADAPTIVE_LOCKMGRS # UTF-8 in console (9.x+) #options TEKEN_UTF8 #options TEKEN_XTERM # NCQ support # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ #options ATA_CAM # FreeBSD 9+ # Deadlock resolver thread # For additional information see http://www.mail-archive.com/[email protected]/msg18124.html #options DEADLKRES PS. Also most of FreeBSD's limits can be monitored by # vmstat -z and # limits PPS. variety of network counters can be monitored via # netstat -s In FreeBSD-9 netstat's -Q option appeared, try following command to display netisr stats # netstat -Q PPPS. also see # man 7 tuning PPPPS. I wanted to thank FreeBSD community, especially author of nginx - Igor Sysoev, nginx-ru@ and FreeBSD-performance@ mailing lists for providing useful information about FreeBSD tuning. So here is the question: What tunings are you using on yours FreeBSD servers? You can also post your /etc/sysctl.conf, /boot/loader.conf, kernel options, etc with description of its' meaning (do not copy-paste from sysctl -d). Don't forget to specify server type (web, smb, gateway, etc) Let's share experience!

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  • How to improve Windows Aero desktop performance?

    - by Click Ok
    Sincerely I don't understand why in Windows Experience ratings, the "Game Graphics" in my pc is 5.0 and "Graphic Elements" (windows aero desktop performance) is 3.9. How it is possible? My VGA is nice for games but bad for Windows Desktop? What I can do to improve windows aero desktop performance?

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  • best practice to removing DC from Site that no longer connects via vpn in another city

    - by dasko
    hi i am looking for a recap of what i have done already to see if i missed anything. i had two cities connected by wan using a ipsec persistent tunnel between gateways. i had one DC (DOMAIN CONTROLLER) in each city that was a global catalog server (GC) they were set up to replicate and i had them configured under Sites and Servers with their own subnet etc... about 6 months ago the one city was removed and i was not able to gracefully remove, through dcpromo, the server that was there. it is no longer used and cannot be brought back. the company went from two sites down to single site. Problem is i had a whole bunch of kcc errors and replication bugs in the event viewer. i wanted to clean up my active directory and decided to use the ntdsutil metadata cleanup commands. i removed the server from the specifed site based on a procedure from petri website. I then removed the instances of the old DC and site from Sites and Servers. Then i went and cleaned up the DNS by removing Host A records, NS server name from both the local DNS forward lookup zone and the _msdcs i also removed the reverse lookup zone for the subnet that no longer exists. is there anything i missed? thanks in advance for any help. gd

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  • Do MSDTC and disaster recovery go together?

    - by DevDelivery
    Our application writes to multiple Sql Server databases within a distributed transaction. The Ops guys are saying that this messes up their disaster recovery plan because while the transactions on the live tables may commit at the same time, the log shipping on the separate databases happen at slightly different times. So in in a disaster recovery situation, there will be a few partial transactions. Is there a method for maintaining separate but synced databases in DR? Or do we have to re-design to relatively independent databases (or a single database)?

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  • VMWare ESX Updates - Which to Apply?

    - by Aaron Alton
    Wondering what more experienced ESX admins typically do... I just brought our ESX hosts up to 3.5 Update 5 (Yes, I know we're behind still). I then applied the "Critical Host Updates" baseline in VMWare update manager, and found that we're still short on 14 "critical updates". My question is, do most people go ahead and apply any update flagged as critical, or do they evaluate each update one-by-one to determine whether or not the issue that has been addressed is likely to affect them. In the SQL Server world (my alma mater, so to speak), we regularly apply service packs, and sometimes cumulative updates, but we only apply hotfixes when the issue that they are targeted towards affects us. Does the same logic hold fast in VMWare land?

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  • Large svn external

    - by MPelletier
    I have a project which uses a large library residing in its own repository. Using: Tortoise-SVN, the server is running an enterprise edition of VisualSVN The project itself has the "standard" structure: trunk tags branches In each branch, tag, and trunk is the library, set as an external (svn:external property). If I get the entire tree, I get the library several times, which is just getting too ridiculously repetitive. Is there a recommended structure for this? Or perhaps a way not to get all externals (because other externals are much smaller, easier to manipulate)?

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  • Best way to replicate / mirror 100s of databases in SQL 2005

    - by mrwayne
    Hi, I currently host around 400-500 SQL 2005 databases of varying sizes (1-10 gig) each. I am aware of most of the different methods available and the general pros/cons of mirroring, log shipping, replication and clustering, but i am not aware of how well they tend to perform when its employed at the size i have specified (400-500 unique databases). Does anyone have any good advice on what is likely the best method for having the ability to fail over to another server with this sort of setup? Fail over does not need to be immediate, i'm just looking for something better than taking backups every day and moving them to storage. I'm preferably looking for something that would also makes it easy to manage the databases in bulk (as opposed to one at a time). Thanks for your input!

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  • Bad to be logged in as admin all the time?

    - by poke
    At the office where I work, three of the other members of the IT staff are logged into their computers all the time with accounts that are members of the domain administrators group. I have serious concerns about being logged in with admin rights (either local or for the domain). As such, for everyday computer use, I use an account that just has regular user privelages. I also have an different account that is part of the domain admins group. I use this account when I need to do something that requires elevated privilages on my computer, one of the servers, or on another user's computer. What is the best practice here? Should network admins be logged in with rights to the entire network all the time (or even their local computer for that matter)?

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