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• What are your suggestions for best practises for regular data updates in a website database?

  - by bboyle1234

  My shared-hosting asp.net website must automatically run data update routines at regular times of day. Once it has finished running certain update routines, it can run update routines that are dependent on the previous updates. I have done this type of work before, using quite complicated setups. Some features of the framework I created are: A cron job from another server makes a request which starts a data update routine on the main server Each updater is loaded from web.config Each updater overrides a "canRunUpdate" method that determines whether its dependencies have finished updating Each updater overrides a "hasFinishedUpdate" method Each updater overrides a "runUpdate" method Updaters start and run in parallel threads The initial request from the cron job server started each updater in its own thread and then ended. As a result, the threads containing the updaters would be terminated before the updaters were finished. Therefore I had to give the updaters the ability to save partial results and continue the update job next time they are started up. As a result, the cron server had to call the updater many times to ensure the job is done. Sometimes the cron server would continue making update requests long after all the updates were completed. Sometimes the cron server would finish calling the update requests and leave some updates uncompleted. It's not the best system. I'm looking for inspiration. Any ideas please? Thank you :)

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• How to multi-thread this?

  - by WilliamKF

  I wish to have two threads. The first thread1 occasionally calls the following pseudo function: void waitForThread2() { if (thread2 is not idle) { return; } notifyThread2IamReady(); while (thread2IsExclusive) { } } The second thread2 is forever in the following pseudo loop: for (;;) { Notify thread1 I am idle. while (!thread1IsReady()) { } Notify thread1 I am exclusive. Do some work while thread1 is blocked. Notify thread1 I am busy. Do some work in parallel with thread1. } What is the best way to write this such that both thread1 and thread2 are kept as busy as possible on a machine with multiple cores. I would like to avoid long delays between notification in one thread and detection by the other. I tried using pthread condition variables but found the delay between thread2 doing 'notify thread1 I am busy' and the loop in waitForThread2() on thear2IsExclusive() can be up to almost one second delay. I then tried using a volatile sig_atomic_t shared variable to control the same, but something is going wrong, so I must not be doing it correctly.

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• Migrate from Oracle to MySQL

  - by Cassy

  Hi together. We ran into serious performance problems with our Oracle database and we would like to try to migrate to a MySQL-based database (either MySQL directly or, more preferrable, Infobright). The thing is, we need to let the old and the new system overlap for at least some weeks if not months, before we actually know, if all features of the new database match our needs. So, here is our situation: The Oracle database consists of multiple tables with each millions of rows. During the day, there are literally thousands of statements, which we cannot stop for migration. Every morning, new data is imported into the Oracle database, replacing some thousands of rows. Copying this process is not a problem, so we could, in theory, import in both databases in parallel. But, and here lies the challenge, for this to work, we need to have an export from the Oracle database with a consistent state from one day. (We cannot export some tables on Monday and some others on Tuesday, etc.) This means, that at least the export should be finished in less than one day. Our first thought was to dump the schema, but I wasn't able to find a tool to import an Oracle dump file into mysql. Exporting tables in CSV files might work, but I'm afraid it could take too long. So my question now is: What should I do? Is there any tool to import Oracle dump files into MySQL? Does anybody have any experience with such a large-scale migration? Thanks in advance, Cassy PS: Please, don't suggest performance optimization techniques for Oracle, we already tried a lot :-)

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• How do I pause main() until all other threads have died?

  - by thechiman

  In my program, I am creating several threads in the main() method. The last line in the main method is a call to System.out.println(), which I don't want to call until all the threads have died. I have tried calling Thread.join() on each thread however that blocks each thread so that they execute sequentially instead of in parallel. Is there a way to block the main() thread until all other threads have finished executing? Here is the relevant part of my code: public static void main(String[] args) { //some other initialization code //Make array of Thread objects Thread[] racecars = new Thread[numberOfRaceCars]; //Fill array with RaceCar objects for(int i=0; i<numberOfRaceCars; i++) { racecars[i] = new RaceCar(laps, args[i]); } //Call start() on each Thread for(int i=0; i<numberOfRaceCars; i++) { racecars[i].start(); try { racecars[i].join(); //This is where I tried to using join() //It just blocks all other threads until the current //thread finishes. } catch(InterruptedException e) { e.printStackTrace(); } } //This is the line I want to execute after all other Threads have finished System.out.println("It's Over!"); } Thanks for the help guys! Eric

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• Unix sort keys cause performance problems

  - by KenFar

  My data: It's a 71 MB file with 1.5 million rows. It has 6 fields All six fields combine to form a unique key - so that's what I need to sort on. Sort statement: sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 -k6,6 -o output.csv input.csv The problem: If I sort without keys, it takes 30 seconds. If I sort with keys, it takes 660 seconds. I need to sort with keys to keep this generic and useful for other files that have non-key fields as well. The 30 second timing is fine, but the 660 is a killer. More details using unix time: sort input.csv -o output.csv = 28 seconds sort -t ',' -k1 input.csv -o output.csv = 28 seconds sort -t ',' -k1,1 input.csv -o output.csv = 64 seconds sort -t ',' -k1,1 -k2,2 input.csv -o output.csv = 194 seconds sort -t ',' -k1,1 -k2,2 -k3,3 input.csv -o output.csv = 328 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 input.csv -o output.csv = 483 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 input.csv -o output.csv = 561 seconds sort -t ',' -k1,1 -k2,2 -k3,3 -k4,4 -k5,5 -k6,6 input.csv -o output.csv = 660 seconds I could theoretically move the temp directory to SSD, and/or split the file into 4 parts, sort them separately (in parallel) then merge the results, etc. But I'm hoping for something simpler since looks like sort is just picking a bad algorithm. Any suggestions? Testing Improvements using buffer-size: With 2 keys I got a 5% improvement with 8, 20, 24 MB and best performance of 8% improvement with 16MB, but 6% worse with 128MB With 6 keys I got a 5% improvement with 8, 20, 24 MB and best performance of 9% improvement with 16MB. Testing improvements using dictionary order (just 1 run each): sort -d --buffer-size=8M -t ',' -k1,1 -k2,2 input.csv -o output.csv = 235 seconds (21% worse) sort -d --buffer-size=8M -t ',' -k1,1 -k2,2 input.csv -o ouput.csv = 232 seconds (21% worse) conclusion: it makes sense that this would slow the process down, not useful Testing with different file system on SSD - I can't do this on this server now. Testing with code to consolidate adjacent keys: def consolidate_keys(key_fields, key_types): """ Inputs: - key_fields - a list of numbers in quotes: ['1','2','3'] - key_types - a list of types of the key_fields: ['integer','string','integer'] Outputs: - key_fields - a consolidated list: ['1,2','3'] - key_types - a list of types of the consolidated list: ['string','integer'] """ assert(len(key_fields) == len(key_types)) def get_min(val): vals = val.split(',') assert(len(vals) <= 2) return vals[0] def get_max(val): vals = val.split(',') assert(len(vals) <= 2) return vals[len(vals)-1] i = 0 while True: try: if ( (int(get_max(key_fields[i])) + 1) == int(key_fields[i+1]) and key_types[i] == key_types[i+1]): key_fields[i] = '%s,%s' % (get_min(key_fields[i]), key_fields[i+1]) key_types[i] = key_types[i] key_fields.pop(i+1) key_types.pop(i+1) continue i = i+1 except IndexError: break # last entry return key_fields, key_types While this code is just a work-around that'll only apply to cases in which I've got a contiguous set of keys - it speeds up the code by 95% in my worst case scenario.

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• Can someone explain RAID-0 in plain English?

  - by Edward Tanguay

  I've heard about and read about RAID throughout the years and understand it theoretically as a way to help e.g. server PCs reduce the chance of data loss, but now I am buying a new PC which I want to be as fast as possible and have learned that having two drives can considerably increase the perceived performance of your machine. In the question Recommendations for hard drive performance boost, the author says he is going to RAID-0 two 7200 RPM drives together. What does this mean in practical terms for me with Windows 7 installed, e.g. can I buy two drives, go into the device manager and "raid-0 them together"? I am not a network administrator or a hardware guy, I'm just a developer who is going to have a computer store build me a super fast machine next week. I can read the wikipedia page on RAID but it is just way too many trees and not enough forest to help me build a faster PC: RAID-0: "Striped set without parity" or "Striping". Provides improved performance and additional storage but no redundancy or fault tolerance. Because there is no redundancy, this level is not actually a Redundant Array of Inexpensive Disks, i.e. not true RAID. However, because of the similarities to RAID (especially the need for a controller to distribute data across multiple disks), simple strip sets are normally referred to as RAID 0. Any disk failure destroys the array, which has greater consequences with more disks in the array (at a minimum, catastrophic data loss is twice as severe compared to single drives without RAID). A single disk failure destroys the entire array because when data is written to a RAID 0 drive, the data is broken into fragments. The number of fragments is dictated by the number of disks in the array. The fragments are written to their respective disks simultaneously on the same sector. This allows smaller sections of the entire chunk of data to be read off the drive in parallel, increasing bandwidth. RAID 0 does not implement error checking so any error is unrecoverable. More disks in the array means higher bandwidth, but greater risk of data loss. So in plain English, how can "RAID-0" help me build a faster Windows-7 PC that I am going to order next week?

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• Linux RAID-0 performance doesn't scale up over 1 GB/s

  - by wazoox

  I have trouble getting the max throughput out of my setup. The hardware is as follow : dual Quad-Core AMD Opteron(tm) Processor 2376 16 GB DDR2 ECC RAM dual Adaptec 52245 RAID controllers 48 1 TB SATA drives set up as 2 RAID-6 arrays (256KB stripe) + spares. Software : Plain vanilla 2.6.32.25 kernel, compiled for AMD-64, optimized for NUMA; Debian Lenny userland. benchmarks run : disktest, bonnie++, dd, etc. All give the same results. No discrepancy here. io scheduler used : noop. Yeah, no trick here. Up until now I basically assumed that striping (RAID 0) several physical devices should augment performance roughly linearly. However this is not the case here : each RAID array achieves about 780 MB/s write, sustained, and 1 GB/s read, sustained. writing to both RAID arrays simultaneously with two different processes gives 750 + 750 MB/s, and reading from both gives 1 + 1 GB/s. however when I stripe both arrays together, using either mdadm or lvm, the performance is about 850 MB/s writing and 1.4 GB/s reading. at least 30% less than expected! running two parallel writer or reader processes against the striped arrays doesn't enhance the figures, in fact it degrades performance even further. So what's happening here? Basically I ruled out bus or memory contention, because when I run dd on both drives simultaneously, aggregate write speed actually reach 1.5 GB/s and reading speed tops 2 GB/s. So it's not the PCIe bus. I suppose it's not the RAM. It's not the filesystem, because I get exactly the same numbers benchmarking against the raw device or using XFS. And I also get exactly the same performance using either LVM striping and md striping. What's wrong? What's preventing a process from going up to the max possible throughput? Is Linux striping defective? What other tests could I run?

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• Vagrant-aws not provisioning

  - by SuperCabbage

  I'm trying to spin up and provision an EC2 instance with Vagrant, it successfully creates the instance up and I can then use vagrant ssh to SSH into the it but Puppet doesn't seem to carry out any provisioning. Upon running vagrant up --provider=aws --provision I get the following output Bringing machine 'default' up with 'aws' provider... WARNING: Nokogiri was built against LibXML version 2.8.0, but has dynamically loaded 2.9.1 [default] Warning! The AWS provider doesn't support any of the Vagrant high-level network configurations (`config.vm.network`). They will be silently ignored. [default] Launching an instance with the following settings... [default] -- Type: m1.small [default] -- AMI: ami-a73264ce [default] -- Region: us-east-1 [default] -- Keypair: banderton [default] -- Block Device Mapping: [] [default] -- Terminate On Shutdown: false [default] Waiting for SSH to become available... [default] Machine is booted and ready for use! [default] Rsyncing folder: /Users/benanderton/development/projects/my-project/aws/ => /vagrant [default] Rsyncing folder: /Users/benanderton/development/projects/my-project/aws/manifests/ => /tmp/vagrant-puppet/manifests [default] Rsyncing folder: /Users/benanderton/development/projects/my-project/aws/modules/ => /tmp/vagrant-puppet/modules-0 [default] Running provisioner: puppet... An error occurred while executing multiple actions in parallel. Any errors that occurred are shown below. An error occurred while executing the action on the 'default' machine. Please handle this error then try again: No error message I can then SSH into the instance by using vagrant ssh but none of my provisioning has taken place, so I'm assuming that errors have occured but I'm not being given any useful information relating to them. My Vagrantfile is as following; Vagrant.configure("2") do |config| config.vm.box = "ubuntu_aws" config.vm.box_url = "https://github.com/mitchellh/vagrant-aws/raw/master/dummy.box" config.vm.provider :aws do |aws, override| aws.access_key_id = "REDACTED" aws.secret_access_key = "REDACTED" aws.keypair_name = "banderton" override.ssh.private_key_path = "~/.ssh/banderton.pem" override.ssh.username = "ubuntu" aws.ami = "ami-a73264ce" end config.vm.provision :puppet do |puppet| puppet.manifests_path = "manifests" puppet.module_path = "modules" puppet.options = ['--verbose'] end end My Puppet manifest is as following; package { [ 'build-essential', 'vim', 'curl', 'git-core', 'nano', 'freetds-bin' ]: ensure => 'installed', } None of the packages are installed.

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• Moving from VPS to Cloud

  - by GRIGORE-TURBODISEL

  ...and I have a few questions. I'm basically working on a MySQL+PHP based webapp. Since I don't have on-demand scaling with VPS, I'm planning to move from VPS to Cloud when I hit the 1000 subscribers barrier. I'm looking at Windows Azure but I'm ok with other suggestions. So here are my questions: Will it really cost me a kidney? Every subscriber needs to download around 4-5MB of static resources each day. Bandwidth is free on the VPS but here I see costs can easily get to $800.00/mo; this makes me very insecure about the whole thing, I mean VPS is just $2,000/yr. Do I need another VM or is PHP included in the Web Sites? I have basic sysadmin skills, I think I can handle setting up a PHP install, but will I have to do this? If yes, what other service do I need to setup manually? What about Memcached, MySQL, etc? What security protections does it include? For example I have some basic protection included, like directory traversals and executable files upload; I also have CloudFlare on my other websites for DDoS protection; will I need to do the same thing here too, can it even be installed, can I edit my DNS records, etc? How are e-mails, subdomains, add-on domains, parked domains, etc. handled? I haven't seen any references to e-mail boxes. On the VPS I simply add them from cPanel ([email protected] / whatever.mysite.com / ...); do I have a similar management interface here? Do I get SSH access? Or at least FTP, remote MySQL access and maybe some incremental back-ups or something? Can I see my quotas and advanced traffic info? I must mention that I really like the idea of the whole "cloud" concept, the added reliability and everything but I really need maybe a parallel to regular hosting or something so I know what to expect.

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• iotop for Linux kernel 2.6.18

  - by Lightsauce

  So it has to come to my attention that iotop isn't availalbe for 2.6.18 since it's less than 2.6.20 and requires Python 2.6+. I've done some research and came across this article: http://lserinol.blogspot.com/2009/09/io-usage-per-process-on-linux.html According to this, if these process have io stats in /proc/pid#/io (where pid# is the process #) it's doable regardless of the kernel version. So, in reality, I could upgrade Python to 2.6 and test out iotop. However, my flavor of Linux, CentOS release 5.5 (Final), only supports Python 2.4.3-44.el5 currently. If I were to do uninstall from yum, it doesn't look so pretty. It ends up wanting to uninstall 235 packages, most of which are very important! I read in one place, online (I forget the URL from yesterday), that you can install Python 2.6+ parallel to this one, and have the rpm install for iotop use that. Well, I didn't choose that route. I figured, what the heck, lets write iotop (not copying it, but reverse engineering it without actually looking at it's code/it in use) in bash. I thought it would just grab the /proc/pid#/io file and parse stats. So I wrote a script to grab the top 10 rchar, wchar, read_bytes, and write_bytes by collecting all these stats from all the /proc/pid#/io files, sorting them by each metric, then grabbing the top 10 highest values. The conclusion, the data seems completely useless. Does anybody know any resources for advanced Linux where I can figure out how to take these /proc/pid#/ directories and figure out what the heck they are doing with io on the disk? My main goal is to figure out what exactly is causing high load on my disk. I just know it's on the / partition (/dev/sda2 in this case), and I'm not really sure how to narrow it down without the help of iotop. If I run iostat to grab metrics for 1 minute, every second, the first result it gives me shows a high 'kB_read/s', so that makes me think, it's reading mostly. However, if I watch the update it gives me every second, it's actually just showing values for kB_wrtn/s. This makes me think the initial value iostat gives me is misleading.

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• What server setup for a small web development company? [closed]

  - by Giordano

  I co-own a company with a friend of mine and we have decided to buy a new server to support our business (our current server is an Asus EEE Box, working great but too limited :) ). I should mention that we are web developers but occasionally we do small-office sys admin. Thus, 99% of time we work on GNU/Linux (mainly Ubuntu) but from time to time we need to setup a Windows environment to assist some customers (e.g. setup a temporary SQL Server 2008). Our requirements: Low budget: we don't want the cheapest solution out there but we can't afford to spend too much. Budget could be ~1000-1500€ (before VAT) Robustness: we would like to setup a RAID array and maybe have an external disk where we can store backups Virtualization: we need to be able to setup few servers for development. The scenario is something like this (~8 appliances running in parallel): Redmine + GIT server Bacula server FTP server 3-4 virtual appliances that could be set up on demand to test our applications or support a customer. The appliances could be: LAMP, Tomcat+PostgreSQL, SQL Server Support: if something breaks down it shouldn't be too difficult to find a replacement. Now, given the main requirements, there are some doubts we need to clarify: Do you suggest to buy a prepackaged solution (for example a customized Dell PowerEdge T110 or T310) or to assemble the server by ourselves (buy the separate components)? What RAID configuration do you suggest? I was thinking of RAID1 (probably cheaper) or RAID5. should we buy a hardware RAID controller or is it ok to use a software RAID (mdadm)? In case, which controller do you suggest? What processor do you suggest (Intel Xeon, i3, i5, i7, AMD)? How much RAM? (I was thinking at least 8GB, ~1GB per appliance) What virtualization software do you recommend? VMWare seems to be the best choice, but what about XEN or KVM? We don't want to buy licenses at the moment so we would like to consider only free options. What OS do you recommend? We know Ubuntu, Debian, Gentoo very well (we would like to use Ubuntu Server), however it seems a lot of people goes for CentOS. Thanks in advance if you can help us with this! It's our first "serious" server so many doubts popped up :) Please feel free to add further recommendations if you have some to share ;) Have a nice day

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• Jquery Slidetoggle open 1 div and close another

  - by Stephen

  I'm trying to close one div when clicking on another div . Currently, it opens multiple divs at one time. JQUERY: $(document).ready(function() { $(".dropdown dt a").click(function() { var dropID = $(this).closest("dl").attr("id"); $("#"+dropID+" dd ul").slideToggle(200); return false; }); $(".dropdown dd ul li a").click(function() { var dropID = $(this).closest("dl").attr("id"); var text = $(this).html(); var selVal = $(this).find(".dropdown_value").html(); $("#"+dropID+" dt a").html(text); $("#"+dropID+" dd ul").hide(); return false; }); $("dl[class!=dropdown]").click(function() { $(".dropdown dd ul").hide(); return false; }); $("id!=quotetoolContainer").click(function() { $(".dropdown dd ul").hide(); return false; }); $('body').click(function() { $(".dropdown dd ul").hide(); return false; }); $('.productSelection').children().hover(function() { $(this).siblings().stop().fadeTo(200,0.5); }, function() { $(this).siblings().stop().fadeTo(200,1); }); }); HTML: <div id="quotetoolContainer"> <div class="top"></div> <div id="quotetool"> <h2>Instant Price Calculator</h2> <p>Document Type</p> <dl id="docType" class="dropdown"> <dt><a href="#"><span>Select a Document Type</span></a></dt> <dd> <ul> <li><a href="#" id="1">Datasheets<span class="value">Datasheets</span></a></li> <li><a href="#">Manuals<span class="value">Manuals</span></a></li> <li><a href="#">Brochures<span class="value">Brochures</span></a></li> <li><a href="#">Newsletters<span class="value">Newsletters</span></a></li> <li><a href="#">Booklets<span class="value">Booklets</span></a></li> </ul> </dd> </dl> <p>Flat Size</p> <dl id="flatSize" class="dropdown"> <dt><a href="#">8.5" x 11"<span class="value">8.5" x 11"</span></a></dt> <dd> <ul> <li><a href="#">8.5" x 11"<span class="value">8.5" x 11"</span></a></li> <li><a href="#">11" x 17"<span class="value">11" x 17"</span></a></li> </ul> </dd> </dl> <p>Full Color or Black &amp; White?</p> <dl id="color" class="dropdown"> <dt><a href="#">Full Color<span class="value">Full Color</span></a></dt> <dd> <ul> <li><a href="#">Full Color<span class="value">Full Color</span></a></li> <li><a href="#">Black &amp; White<span class="value">Black &amp; White</span></a></li> </ul> </dd> </dl> <p>Paper</p> <dl id="paper" class="dropdown"> <dt><a href="#">Value White Paper (20 lb.)<span class="value">Value White Paper (20 lb.)</span></a></dt> <dd> <ul> <li><a href="#">Value White Paper (20 lb.)<span class="value">Value White Paper (20 lb.)</span></a></li> <li><a href="#">Premium White Paper (28 lb.)<span class="value">Premium White Paper (28 lb.)</span></a></li> <li><a href="#">Glossy White Text (80 lb.) - Recycled<span class="value">Glossy White Text (80 lb.) - Recycled</span></a></li> <li><a href="#">Glossy White Cover (80 lb.) - Recycled<span class="value">Glossy White Cover (80 lb.) - Recycled</span></a></li> </ul> </dd> </dl> <p>Folding</p> <dl id="folding" class="dropdown"> <dt><a href="#">Fold in Half<span class="value">Fold in Half</span></a></dt> <dd> <ul> <li><a href="#">Fold in Half<span class="value">Fold in Half</span></a></li> <li><a href="#">Tri-Fold<span class="value">Tri-Fold</span></a></li> <li><a href="#">Z-Fold<span class="value">Z-Fold</span></a></li> <li><a href="#">Double-Parallel Fold<span class="value">Double-Parallel Fold</span></a></li> </ul> </dd> </dl> <p>Three-Hole Drill</p> <dl id="drill" class="dropdown"> <dt><a href="#">No<span class="value">No</span></a></dt> <dd> <ul> <li><a href="#">No<span class="value">No</span></a></li> <li><a href="#">Yes<span class="value">Yes</span></a></li> </ul> </dd> </dl> <p>Qty</p> <dl id="quantity" class="dropdown"> <dt><a href="#">50<span class="value">50</span></a></dt> <dd> <ul> <li><a href="#">50<span class="value">50</span></a></li> <li><a href="#">100<span class="value">100</span></a></li> <li><a href="#">150<span class="value">150</span></a></li> <li><a href="#">200<span class="value">200</span></a></li> <li><a href="#">250<span class="value">250</span></a></li> <li><a href="#">500<span class="value">500</span></a></li> <li><a href="#">750<span class="value">750</span></a></li> <li><a href="#">1,000<span class="value">1,000</span></a></li> <li><a href="#">1,500<span class="value">1,500</span></a></li> <li><a href="#">2,000<span class="value">2,000</span></a></li> <li><a href="#">2,500<span class="value">2,500</span></a></li> <li><a href="#">3,000<span class="value">3,000</span></a></li> <li><a href="#">3,500<span class="value">3,500</span></a></li> <li><a href="#">4,000<span class="value">4,000</span></a></li> <li><a href="#">4,500<span class="value">4,500</span></a></li> <li><a href="#">5,000<span class="value">5,000</span></a></li> <li><a href="#">5,500<span class="value">5,500</span></a></li> <li><a href="#">6,000<span class="value">6,000</span></a></li> <li><a href="#">6,500<span class="value">6,500</span></a></li> <li><a href="#">7,000<span class="value">7,000</span></a></li> <li><a href="#">7,500<span class="value">7,500</span></a></li> <li><a href="#">8,000<span class="value">8,000</span></a></li> <li><a href="#">8,500<span class="value">8,500</span></a></li> <li><a href="#">9,000<span class="value">9,000</span></a></li> <li><a href="#">9,500<span class="value">9,500</span></a></li> <li><a href="#">10,000<span class="value">10,000</span></a></li> <li><a href="#">12,500<span class="value">12,500</span></a></li> <li><a href="#">15,000<span class="value">15,000</span></a></li> <li><a href="#">17,500<span class="value">17,500</span></a></li> <li><a href="#">20,000<span class="value">20,000</span></a></li> </ul> </dd> </dl> <div id="priceTotal"> <div class="priceText">Your Price:</div> <div class="price">$29.00</div> <div class="clear"></div> </div> <div id="buttonQuoteStart"><a href="#" title="Start Printing">Start Printing</a></div> </div> <div class="bottom"></div> </div>

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• EXC_BAD_ACCESS and KERN_INVALID_ADDRESS after intiating a print sequence.

  - by Edward M. Bergmann

  MAC G4/1.5GHz/2GB/1TB+ OS10.4.11 Start up Volume has been erased/complete reinstall with updated software. Current problem only occurs when printing to an Epson Artisan 800 [USB as well as Ethernet connected] when using Macromedia FreeHand 10.0.1.67. All other apps/printers work fine. Memory has been removed/swapped/reinstalled several times, CPU was changed from 1.5GB to 1.3GB. Page(s) will print, but application quits within a second or two after selecting "print." Apple has never replied, Epson hasn't a clue, and I am befuddled!! Perhaps there is GURU out their who and see a bigger-better picture and understands how to interpret all of this stuff. If so, it would be a terrific pleasure to get a handle on how to cure this problem or get some A M M U N I T I O N to fire in the right direction. I thank you in advance. FreeHand 10 MAC OS10.4.11 unexpectedly quits after invoking a print command, the result: Date/Time: 2010-04-20 14:23:18.371 -0700 OS Version: 10.4.11 (Build 8S165) Report Version: 4 Command: FreeHand 10 Path: /Applications/Macromedia FreeHand 10.0.1.67/FreeHand 10 Parent: WindowServer [1060] Version: 10.0.1.67 (10.0.1.67, Copyright © 1988-2002 Macromedia Inc. and its licensors. All rights reserved.) PID: 1217 Thread: 0 Exception: EXC_BAD_ACCESS (0x0001) Codes: KERN_INVALID_ADDRESS (0x0001) at 0x07d7e000 Thread 0 Crashed: 0 <<00000000>> 0xffff8a60 __memcpy + 704 (cpu_capabilities.h:189) 1 FreeHand X 0x011d2994 0x1008000 + 1878420 2 FreeHand X 0x01081da4 0x1008000 + 499108 3 FreeHand X 0x010f5474 0x1008000 + 971892 4 FreeHand X 0x010d0278 0x1008000 + 819832 5 FreeHand X 0x010fa808 0x1008000 + 993288 6 FreeHand X 0x01113608 0x1008000 + 1095176 7 FreeHand X 0x01113748 0x1008000 + 1095496 8 FreeHand X 0x01099ebc 0x1008000 + 597692 9 FreeHand X 0x010fa358 0x1008000 + 992088 10 FreeHand X 0x010fa170 0x1008000 + 991600 11 FreeHand X 0x010f9830 0x1008000 + 989232 12 FreeHand X 0x01098678 0x1008000 + 591480 13 FreeHand X 0x010f7a5c 0x1008000 + 981596 Thread 1: 0 libSystem.B.dylib 0x90005dec syscall + 12 1 com.apple.OpenTransport 0x9ad015a0 BSD_waitevent + 44 2 com.apple.OpenTransport 0x9ad06360 CarbonSelectThreadFunc + 176 3 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 2: 0 libSystem.B.dylib 0x9002bfc8 semaphore_wait_signal_trap + 8 1 libSystem.B.dylib 0x90030aac pthread_cond_wait + 480 2 com.apple.OpenTransport 0x9ad01e94 CarbonOperationThreadFunc + 80 3 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 3: 0 libSystem.B.dylib 0x9002bfc8 semaphore_wait_signal_trap + 8 1 libSystem.B.dylib 0x90030aac pthread_cond_wait + 480 2 com.apple.OpenTransport 0x9ad11df0 CarbonInetOperThreadFunc + 80 3 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 4: 0 libSystem.B.dylib 0x90053f88 semaphore_timedwait_signal_trap + 8 1 libSystem.B.dylib 0x900707e8 pthread_cond_timedwait_relative_np + 556 2 ...ple.CoreServices.CarbonCore 0x90bf9330 TSWaitOnSemaphoreCommon + 176 3 ...ple.CoreServices.CarbonCore 0x90c012d0 TimerThread + 60 4 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 5: 0 libSystem.B.dylib 0x9001f48c select + 12 1 com.apple.CoreFoundation 0x907f1240 __CFSocketManager + 472 2 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 6: 0 libSystem.B.dylib 0x9002188c access + 12 1 ...e.print.framework.PrintCore 0x9169a620 CreateProxyURL(__CFURL const*) + 192 2 ...e.print.framework.PrintCore 0x9169a4f8 CreateOriginalPrinterProxyURL() + 80 3 ...e.print.framework.PrintCore 0x9169a034 CheckPrinterProxyVersion(OpaquePMPrinter*, __CFURL const*) + 192 4 ...e.print.framework.PrintCore 0x91699d94 PJCPrinterProxyCreateURL + 932 5 ...e.print.framework.PrintCore 0x916997bc PJCLaunchPrinterProxy(OpaquePMPrinter*, PMLaunchPCReason) + 32 6 ...e.print.framework.PrintCore 0x91699730 PJCLaunchPrinterProxyThread(void*) + 136 7 libSystem.B.dylib 0x9002b908 _pthread_body + 96 Thread 0 crashed with PPC Thread State 64: srr0: 0x00000000ffff8a60 srr1: 0x000000000200f030 vrsave: 0x00000000ff000000 cr: 0x24002244 xer: 0x0000000020000002 lr: 0x00000000011d2994 ctr: 0x00000000000003f6 r0: 0x0000000000000000 r1: 0x00000000bfffea60 r2: 0x0000000000000000 r3: 0x00000000083bb000 r4: 0x00000000083c0040 r5: 0x0000000000014d84 r6: 0x0000000000000010 r7: 0x0000000000000020 r8: 0x0000000000000030 r9: 0x0000000000000000 r10: 0x0000000000000060 r11: 0x0000000000000080 r12: 0x0000000007d7e000 r13: 0x0000000000000000 r14: 0x00000000005cbd26 r15: 0x0000000000000001 r16: 0x00000000017b03a0 r17: 0x0000000000000000 r18: 0x000000000068fa80 r19: 0x0000000000000001 r20: 0x0000000006c639c4 r21: 0x00000000006900f8 r22: 0x0000000006e09480 r23: 0x0000000006e0a250 r24: 0x0000000000000002 r25: 0x0000000000000000 r26: 0x00000000bfffed2c r27: 0x0000000006e05ce0 r28: 0x0000000000014d84 r29: 0x0000000000000000 r30: 0x0000000000014d84 r31: 0x00000000083bb000 Binary Images Description: 0x1000 - 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0x5d4b0de Spiral PEF binary: Spiral 0x5d4c000 - 0x5d57f07 Targa Import Export8 PEF binary: Targa Import Export8 0x5d58000 - 0x5d8d959 TIFF Import Export68 PEF binary: TIFF Import Export68 0x5d93000 - 0x5da0f65 Color Utilities PEF binary: Color Utilities 0x5f62000 - 0x5f6e795 Mirror PEF binary: Mirror 0x5f6f000 - 0x5fbd656 HTML Export PEF binary: HTML Export 0x5fc8000 - 0x5fd442f Graphic Hose PEF binary: Graphic Hose 0x5fd5000 - 0x5fe4b5a BMP Import Exportr68 PEF binary: BMP Import Exportr68 0x5fe5000 - 0x60342d6 PDF Export PEF binary: PDF Export 0x6041000 - 0x6042f44 Fractalizej@ PEF binary: Fractalizej@ 0x6043000 - 0x6075214 Chart Tool™ PEF binary: Chart Tool™ 0x6076000 - 0x607d46d Bend PEF binary: Bend 0x607e000 - 0x60cda7b PDF Import PEF binary: PDF Import 0x60dc000 - 0x60e38f2 Photoshop ImportChartCursor PEF binary: Photoshop ImportChartCursor 0x60e4000 - 0x60eb9b1 3D Rotationp PEF binary: 3D Rotationp 0x60ec000 - 0x611b458 JPEG Import ExportANEL PEF binary: JPEG Import ExportANEL 0x611c000 - 0x613d89f GIF Import Export PEF binary: GIF Import Export 0x613e000 - 0x616d7f7 Flash Export PEF binary: Flash Export 0x616e000 - 0x6175d75 Fisheye Lens PEF binary: Fisheye Lens 0x6176000 - 0x6182343 IPTC File Info PEF binary: IPTC File Info 0x6184000 - 0x6193790 PEF binary: 0x6194000 - 0x61965e5 Photoshop Palette Import PEF binary: Photoshop Palette Import 0x6197000 - 0x619c5a4 Add PointsZ PEF binary: Add PointsZ 0x619d000 - 0x61ad92b Emboss PEF binary: Emboss 0x61ae000 - 0x61be6e1 AppleScript™ Xtrawpc PEF binary: AppleScript™ Xtrawpc 0x61bf000 - 0x61d16de Navigation PEF binary: Navigation 0x61d2000 - 0x61ff94e CorelDRAW 7-8 Import PEF binary: CorelDRAW 7-8 Import 0x620a000 - 0x620d7f1 Trap PEF binary: Trap 0x620e000 - 0x62149d4 Import RGB Color Table PEF binary: Import RGB Color Table 0x6215000 - 0x6217dfe Arc PEF binary: Arc 0x6218000 - 0x62211e3 Delete Empty Text Blocks PEF binary: Delete Empty Text Blocks 0x6222000 - 0x624c8da MIX Services PEF binary: MIX Services 0x7d0b000 - 0x7d37fff com.apple.print.framework.Print.Private 4.6 (163.10) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Print.framework/Versions/Current/Plugins/PrintCocoaUI.bundle/Contents/MacOS/PrintCocoaUI 0x7dbf000 - 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0x92af5fff libiconv.2.dylib /usr/lib/libiconv.2.dylib 0x92af8000 - 0x92b80fff com.apple.DesktopServices 1.3.7 /System/Library/PrivateFrameworks/DesktopServicesPriv.framework/Versions/A/DesktopServicesPriv 0x92bc1000 - 0x92df4fff com.apple.Foundation 6.4.12 (567.42) /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation 0x92f27000 - 0x92f45fff libGL.dylib /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGL.dylib 0x92f50000 - 0x92faafff libGLU.dylib /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLU.dylib 0x92fc8000 - 0x92fc8fff com.apple.Carbon 10.4 (???) /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon 0x92fca000 - 0x92fdefff com.apple.ImageCapture 3.0 /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/ImageCapture.framework/Versions/A/ImageCapture 0x92ff6000 - 0x93006fff com.apple.speech.recognition.framework 3.4 /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/SpeechRecognition.framework/Versions/A/SpeechRecognition 0x93012000 - 0x93027fff com.apple.securityhi 2.0 (203) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/SecurityHI.framework/Versions/A/SecurityHI 0x93039000 - 0x930c0fff com.apple.ink.framework 101.2 (69) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Ink.framework/Versions/A/Ink 0x930d4000 - 0x930dffff com.apple.help 1.0.3 (32) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Help.framework/Versions/A/Help 0x930e9000 - 0x93117fff com.apple.openscripting 1.2.7 (???) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/OpenScripting.framework/Versions/A/OpenScripting 0x93131000 - 0x93140fff com.apple.print.framework.Print 5.2 (192.4) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/Print.framework/Versions/A/Print 0x9314c000 - 0x931b2fff com.apple.htmlrendering 1.1.2 /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HTMLRendering.framework/Versions/A/HTMLRendering 0x931e3000 - 0x93232fff com.apple.NavigationServices 3.4.4 (3.4.3) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/NavigationServices.framework/Versions/A/NavigationServices 0x93260000 - 0x9327dfff com.apple.audio.SoundManager 3.9 /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/CarbonSound.framework/Versions/A/CarbonSound 0x9328f000 - 0x9329cfff com.apple.CommonPanels 1.2.2 (73) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/CommonPanels.framework/Versions/A/CommonPanels 0x932a5000 - 0x935b3fff com.apple.HIToolbox 1.4.10 (???) /System/Library/Frameworks/Carbon.framework/Versions/A/Frameworks/HIToolbox.framework/Versions/A/HIToolbox 0x93703000 - 0x9370ffff com.apple.opengl 1.4.7 /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL 0x93714000 - 0x93734fff com.apple.DirectoryService.Framework 3.3 /System/Library/Frameworks/DirectoryService.framework/Versions/A/DirectoryService 0x93787000 - 0x93787fff com.apple.Cocoa 6.4 (???) /System/Library/Frameworks/Cocoa.framework/Versions/A/Cocoa 0x93789000 - 0x93dbcfff com.apple.AppKit 6.4.10 (824.48) /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit 0x94149000 - 0x941bbfff com.apple.CoreData 91 (92.1) /System/Library/Frameworks/CoreData.framework/Versions/A/CoreData 0x941f4000 - 0x942b9fff com.apple.audio.toolbox.AudioToolbox 1.4.7 /System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox 0x9430c000 - 0x9430cfff com.apple.audio.units.AudioUnit 1.4 /System/Library/Frameworks/AudioUnit.framework/Versions/A/AudioUnit 0x9430e000 - 0x944cefff com.apple.QuartzCore 1.4.12 /System/Library/Frameworks/QuartzCore.framework/Versions/A/QuartzCore 0x94518000 - 0x94555fff libsqlite3.0.dylib /usr/lib/libsqlite3.0.dylib 0x9455d000 - 0x945adfff libGLImage.dylib /System/Library/Frameworks/OpenGL.framework/Versions/A/Libraries/libGLImage.dylib 0x945b6000 - 0x945cffff com.apple.CoreVideo 1.4.2 /System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo 0x9477d000 - 0x9478cfff libCGATS.A.dylib /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libCGATS.A.dylib 0x94794000 - 0x947a1fff libCSync.A.dylib /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libCSync.A.dylib 0x947a7000 - 0x947c6fff libPDFRIP.A.dylib /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libPDFRIP.A.dylib 0x947e7000 - 0x94800fff libRIP.A.dylib /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libRIP.A.dylib 0x94807000 - 0x94b3afff com.apple.QuickTime 7.6.4 (1327.73) /System/Library/Frameworks/QuickTime.framework/Versions/A/QuickTime 0x94c22000 - 0x94c93fff libstdc++.6.dylib /usr/lib/libstdc++.6.dylib 0x94e09000 - 0x94f39fff com.apple.AddressBook.framework 4.0.6 (490) /System/Library/Frameworks/AddressBook.framework/Versions/A/AddressBook 0x94fcc000 - 0x94fdbfff com.apple.DSObjCWrappers.Framework 1.1 /System/Library/PrivateFrameworks/DSObjCWrappers.framework/Versions/A/DSObjCWrappers 0x94fe3000 - 0x95010fff com.apple.LDAPFramework 1.4.1 (69.0.1) /System/Library/Frameworks/LDAP.framework/Versions/A/LDAP 0x95017000 - 0x95027fff libsasl2.2.dylib /usr/lib/libsasl2.2.dylib 0x9502b000 - 0x9505afff libssl.0.9.7.dylib /usr/lib/libssl.0.9.7.dylib 0x9506a000 - 0x95087fff libresolv.9.dylib /usr/lib/libresolv.9.dylib 0x9acff000 - 0x9ad1dfff com.apple.OpenTransport 2.0 /System/Library/PrivateFrameworks/OpenTransport.framework/OpenTransport 0x9ad98000 - 0x9ad99fff com.apple.iokit.dvcomponentglue 1.7.9 /System/Library/Frameworks/DVComponentGlue.framework/Versions/A/DVComponentGlue 0x9b1db000 - 0x9b1f2fff libCFilter.A.dylib /System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/CoreGraphics.framework/Versions/A/Resources/libCFilter.A.dylib 0x9c69b000 - 0x9c6bdfff libmx.A.dylib /usr/lib/libmx.A.dylib 0xeab00000 - 0xeab25fff libConverter.dylib /System/Library/Printers/Libraries/libConverter.dylib Model: PowerMac3,1, BootROM 4.2.8f1, 1 processors, PowerPC G4 (3.3), 1.3 GHz, 2 GB Graphics: ATI Radeon 7500, ATY,RV200, AGP, 32 MB Memory Module: DIMM0/J21, 512 MB, SDRAM, PC133-333 Memory Module: DIMM1/J22, 512 MB, SDRAM, PC133-333 Memory Module: DIMM2/J23, 512 MB, SDRAM, PC133-333 Memory Module: DIMM3/J24, 512 MB, SDRAM, PC133-333 Modem: Spring, UCJ, V.90, 3.0F, APPLE VERSION 0001, 4/7/1999 Network Service: Built-in Ethernet, Ethernet, en0 PCI Card: SeriTek/1V2E2 v.5.1.3,11/22/05, 23:47:18, ata, SLOT-B PCI Card: pci-bridge, pci, SLOT-C PCI Card: firewire, ieee1394, 2x8 PCI Card: usb, usb, 2x9 PCI Card: usb, usb, 2x9 PCI Card: pcie55,2928, 2x9 PCI Card: ATTO,ExpressPCIPro, scsi, SLOT-D Parallel ATA Device: MATSHITADVD-ROM SR-8585 Parallel ATA Device: IOMEGA ZIP 100 ATAPI USB Device: Hub, Up to 12 Mb/sec, 500 mA USB Device: Hub, Up to 12 Mb/sec, 500 mA USB Device: USB2.0 Hub, Up to 12 Mb/sec, 500 mA USB Device: iMic USB audio system, Griffin Technology, Inc, Up to 12 Mb/sec, 500 mA USB Device: USB Storage Device, Generic, Up to 12 Mb/sec, 500 mA USB Device: USB2.0 MFP, EPSON, Up to 12 Mb/sec, 500 mA USB Device: DYMO LabelWriter Twin Turbo, DYMO, Up to 12 Mb/sec, 500 mA USB Device: USB 2.0 CD + HDD, DMI, Up to 12 Mb/sec, 500 mA USB Device: USB2.0 Hub, Up to 12 Mb/sec, 500 mA USB Device: USB2.0 Hub, Up to 12 Mb/sec, 500 mA USB Device: iMate, USB To ADB Adaptor, Griffin Technology, Inc., Up to 1.5 Mb/sec, 500 mA USB Device: Hub in Apple Pro Keyboard, Alps Electric, Up to 12 Mb/sec, 500 mA USB Device: Griffin PowerMate, Griffin Technology, Inc., Up to 1.5 Mb/sec, 100 mA

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• JSF index out of bounds exception when submiting a form

  - by selvin

  When I click submit button in a JSF form the following exception occurs. It says an Indexout of bounds exception, but I did not use any ArrayList associated with the code. Is this a bug? what should i do to get rid of this error.. Mojarra: 2.0.2 FCS with primefaces 2.2 JSF: 2.0 NetBeans IDE 6.8 Glassfish Domain V3 Form Code: <p:panel id="jobres" style="min-width: 200px" header="Reservation" widgetVar="jres" closable="true" toggleable="true" > <h:form id="arj" prependId="false" style="width:550px;max-height:400px;overflow:auto;"> <p:tooltip global="true"/> <h:panelGrid columns="2" > <p:panel style="min-width: 220px"> <h:outputLabel value="1.Job type:"/> </p:panel> <h:panelGroup> <h:messages id="aerr"/> <h:selectOneMenu title="Choose a Jobtype" value="#{arjob.jobtype}"> <f:selectItem itemLabel="Sequential" itemValue="sequential"/> <f:selectItem itemLabel="Parallel" itemValue="parallel"/> </h:selectOneMenu> </h:panelGroup> <p:panel> <h:outputLabel value="2.Executable: *"/> </p:panel> <h:panelGroup> <p:fileUpload id="aexeupload" fileUploadListener="#{arjob.chooseListener}" auto="true" update="adlist :erdialog" description="Resource Files"> </p:fileUpload> <br/> <h:panelGroup id="aexelistwrapper"> <p:dataList var="fileList" type="ordered" id="adlist" value="#{arjob.fexelist}"> <p:column> #{fileList}&nbsp; <p:commandLink ajax="true" update="aexelistwrapper" actionListener="#{arjob.removeExe(fileList)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGroup> </h:panelGroup> <p:panel> <h:outputLabel value="3.Argument(s):"/> </p:panel> <h:panelGroup> <u style="color:orange"> <i> <p:inplace emptyLabel="Add Arguments" onEditUpdate="aarglist"> <h:inputText title="Enter the arguments" id="aiparg" value="#{arjob.args}"> <f:ajax event="valueChange"/> </h:inputText> <p:commandButton update="aarglistwrapper erdialog" value="add" actionListener="#{arjob.addArg}"/> </p:inplace> </i> </u> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <h:panelGrid id="aarglistwrapper"> <p:dataList id="aarglist" type="ordered" var="args" value="#{arjob.arglist}"> <p:column id="col2"> #{args}&nbsp; <p:commandLink ajax="true" update="arj:arglistwrapper" actionListener="#{arjob.removeArgs(args)}"> <p:graphicImage title="remove" value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGrid> </h:panelGroup> <p:panel> <h:outputLabel value="4.InputFile(s): *"/> </p:panel> <h:panelGroup> <p:fileUpload id="ainpupload" fileUploadListener="#{arjob.inputChooseListener}" auto="true" update="aipfilelistwrapper :erdialog" description="Resource Files"> </p:fileUpload> <br/> <h:panelGroup id="aipfilelistwrapper"> <p:dataList var="ipfile" type="ordered" id="aipflist" value="#{arjob.finlist}"> <p:column> #{ipfile}&nbsp; <p:commandLink ajax="true" update="aipfilelistwrapper" actionListener="#{arjob.removeInfile(ipfile)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGroup> </h:panelGroup> <h:panelGroup> <p:panel > 5)Output File(s): </p:panel> </h:panelGroup> <h:panelGroup> <u style="color:orange"> <i> <p:inplace emptyLabel="Add file name" id="aipexe"> <h:inputText title="Enter the output filenames" id="aexe" value="#{arjob.ofilename}"> <f:ajax event="valueChange"/> </h:inputText> <p:commandButton update="adoutlist :erdialog" value="add" actionListener="#{arjob.addOutfile}"/> </p:inplace> </i> </u> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <h:panelGrid id="afilelistwrapper"> <p:dataList id="adoutlist" type="ordered" var="ofile" value="#{arjob.foutlist}"> <p:column id="acol"> #{ofile}&nbsp; <p:commandLink ajax="true" update="afilelistwrapper" actionListener="#{arjob.removeOutfile(ofile)}"> <p:graphicImage value="images/closebar.png"/> </p:commandLink> </p:column> </p:dataList> </h:panelGrid> </h:panelGroup> <p:panel> <h:outputLabel value="6) Operating System"/> </p:panel> <h:panelGroup> <h:selectOneMenu title="Select an OperatingSystem" value="#{arjob.os}"> <f:selectItem itemLabel="CentOS Release 5.2" itemValue="Cent OS 5.2"/> <f:selectItem itemLabel="RHEL Server Release 5" itemValue="RHEL server 5"/> <f:selectItem itemLabel="RHEL Server Release 5.2" itemValue="RHEL server 5.2"/> </h:selectOneMenu> </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="7) Physical Memory:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.mem}"> </p:spinner>(MB) </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="8) Disk Space:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.diskspace}"> </p:spinner>(MB) </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="9) CPU Mhz:"/> </p:panel> </h:panelGroup> <h:panelGroup> <p:spinner min="0" style="width: 100px" stepFactor="10" value="#{arjob.cpumhz}"> </p:spinner>(Mhz) </h:panelGroup> <p:panel> <h:outputLabel value="10) Start Time:"/> </p:panel> <h:panelGroup> <p:inputMask title="(YYYY-MM-DD HH:MM:SS)" mask="9999-99-99 99:99:99" value="#{arjob.startt}"> </p:inputMask> </h:panelGroup> <p:panel> <h:outputLabel value="11) End Time:"/> </p:panel> <h:panelGroup> <p:inputMask title="(YYYY-MM-DD HH:MM:SS)" mask="9999-99-99 99:99:99" value="#{arjob.endt}"> <p:ajax event="valueChange"/> </p:inputMask> </h:panelGroup> <p:panel> <h:outputLabel value="12) LRMS type"/> </p:panel> <h:panelGroup> <h:selectOneMenu value="#{arjob.lrms}"> <f:selectItem itemLabel="PBS" itemValue="PBS"/> <f:selectItem itemLabel="SGE" itemValue="SGE"/> </h:selectOneMenu> </h:panelGroup> <h:panelGroup> <p:panel> <h:outputLabel value="13)Number of Nodes: *"/> </p:panel> </h:panelGroup> <h:panelGroup> <h:panelGroup> <p:spinner style="width: 100px" min="1" max="100" value="#{arjob.numnodes}"> </p:spinner> </h:panelGroup> </h:panelGroup> <h:panelGroup> </h:panelGroup> <h:panelGroup> <p:commandButton ajax="false" value="Submit" action="#{arjob.jobSubmitAction}"/> </h:panelGroup> </h:panelGrid> </h:form> <p:draggable for="jobres" handle=".ui-panel-titlebar"/> </p:panel> Exception: SEVERE: javax.faces.FacesException: Unexpected error restoring state for component with id j_idt7. Cause: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0. at com.sun.faces.application.view.StateManagementStrategyImpl$2.visit(StateManagementStrategyImpl.java:239) at com.sun.faces.component.visit.FullVisitContext.invokeVisitCallback(FullVisitContext.java:147) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1446) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at javax.faces.component.UIComponent.visitTree(UIComponent.java:1457) at com.sun.faces.application.view.StateManagementStrategyImpl.restoreView(StateManagementStrategyImpl.java:223) at com.sun.faces.application.StateManagerImpl.restoreView(StateManagerImpl.java:177) at com.sun.faces.application.view.ViewHandlingStrategy.restoreView(ViewHandlingStrategy.java:131) at com.sun.faces.application.view.FaceletViewHandlingStrategy.restoreView(FaceletViewHandlingStrategy.java:430) at com.sun.faces.application.view.MultiViewHandler.restoreView(MultiViewHandler.java:143) at javax.faces.application.ViewHandlerWrapper.restoreView(ViewHandlerWrapper.java:288) at com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:199) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:110) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:277) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:332) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:233) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:619) Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0 at java.util.ArrayList.RangeCheck(ArrayList.java:547) at java.util.ArrayList.get(ArrayList.java:322) at javax.faces.component.AttachedObjectListHolder.restoreState(AttachedObjectListHolder.java:161) at javax.faces.component.UIComponentBase.restoreState(UIComponentBase.java:1427) at com.sun.faces.application.view.StateManagementStrategyImpl$2.visit(StateManagementStrategyImpl.java:231) ... 45 more

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• Parallelism in .NET – Part 13, Introducing the Task class

  - by Reed

  Once we’ve used a task-based decomposition to decompose a problem, we need a clean abstraction usable to implement the resulting decomposition.  Given that task decomposition is founded upon defining discrete tasks, .NET 4 has introduced a new API for dealing with task related issues, the aptly named Task class. The Task class is a wrapper for a delegate representing a single, discrete task within your decomposition.  We will go into various methods of construction for tasks later, but, when reduced to its fundamentals, an instance of a Task is nothing more than a wrapper around a delegate with some utility functionality added.  In order to fully understand the Task class within the new Task Parallel Library, it is important to realize that a task really is just a delegate – nothing more.  In particular, note that I never mentioned threading or parallelism in my description of a Task.  Although the Task class exists in the new System.Threading.Tasks namespace: Tasks are not directly related to threads or multithreading. Of course, Task instances will typically be used in our implementation of concurrency within an application, but the Task class itself does not provide the concurrency used.  The Task API supports using Tasks in an entirely single threaded, synchronous manner. Tasks are very much like standard delegates.  You can execute a task synchronously via Task.RunSynchronously(), or you can use Task.Start() to schedule a task to run, typically asynchronously.  This is very similar to using delegate.Invoke to execute a delegate synchronously, or using delegate.BeginInvoke to execute it asynchronously. The Task class adds some nice functionality on top of a standard delegate which improves usability in both synchronous and multithreaded environments. The first addition provided by Task is a means of handling cancellation via the new unified cancellation mechanism of .NET 4.  If the wrapped delegate within a Task raises an OperationCanceledException during it’s operation, which is typically generated via calling ThrowIfCancellationRequested on a CancellationToken, or if the CancellationToken used to construct a Task instance is flagged as canceled, the Task’s IsCanceled property will be set to true automatically.  This provides a clean way to determine whether a Task has been canceled, often without requiring specific exception handling. Tasks also provide a clean API which can be used for waiting on a task.  Although the Task class explicitly implements IAsyncResult, Tasks provide a nicer usage model than the traditional .NET Asynchronous Programming Model.  Instead of needing to track an IAsyncResult handle, you can just directly call Task.Wait() to block until a Task has completed.  Overloads exist for providing a timeout, a CancellationToken, or both to prevent waiting indefinitely.  In addition, the Task class provides static methods for waiting on multiple tasks – Task.WaitAll and Task.WaitAny, again with overloads providing time out options.  This provides a very simple, clean API for waiting on single or multiple tasks. Finally, Tasks provide a much nicer model for Exception handling.  If the delegate wrapped within a Task raises an exception, the exception will automatically get wrapped into an AggregateException and exposed via the Task.Exception property.  This exception is stored with the Task directly, and does not tear down the application.  Later, when Task.Wait() (or Task.WaitAll or Task.WaitAny) is called on this task, an AggregateException will be raised at that point if any of the tasks raised an exception.  For example, suppose we have the following code: Task taskOne = new Task( () => { throw new ApplicationException("Random Exception!"); }); Task taskTwo = new Task( () => { throw new ArgumentException("Different exception here"); }); // Start the tasks taskOne.Start(); taskTwo.Start(); try { Task.WaitAll(new[] { taskOne, taskTwo }); } catch (AggregateException e) { Console.WriteLine(e.InnerExceptions.Count); foreach (var inner in e.InnerExceptions) Console.WriteLine(inner.Message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, our routine will print: 2 Different exception here Random Exception! Note that we had two separate tasks, each of which raised two distinctly different types of exceptions.  We can handle this cleanly, with very little code, in a much nicer manner than the Asynchronous Programming API.  We no longer need to handle TargetInvocationException or worry about implementing the Event-based Asynchronous Pattern properly by setting the AsyncCompletedEventArgs.Error property.  Instead, we just raise our exception as normal, and handle AggregateException in a single location in our calling code.

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• Ich bin jetzt Oracle Certified Associate!

  - by britta.wolf

  Jan Peuker, Absolvent der Hochschule Augsburg und University of Melbourne, hat vor kurzem das Zertifikat Oracle Database 10g Administrator Certified Associate erworben. Er hat uns netterweise mit diesem kleinen Text versorgt: "Die Oracle Zertifizierung beginnt üblicherweise mit dem Oracle Certified Associate. Für diese Zertifizierung ist noch keine tiefgehende Praxiserfahrung notwendig. Um den Titel des Oracle Database 11g Administrator Certified Associate zu erlangen, muss man eine Prüfung zu SQL (z.B. 1Z0-051) sowie eine Prüfung zur Administration (1Z0-045) ablegen. Beide Prüfungen dauern 2 Stunden und haben ca. 80 Fragen von denen etwa drei Viertel richtig beantwortet werden müssen, um zu bestehen. Eine Note gibt es nicht. Die Prüfungen finden immer elektronisch statt, die Software erlaubt das Überspringen und Markieren von Fragen. Während meiner Arbeitszeit nach meinem ersten Studium hatte ich häufig mit dem Oracle Datenbanksystem zu tun. Als ich mein Aufbaustudium an der University of Melbourne absolvierte, wurde mir von der Studienberaterin vorgeschlagen, den Kurs „Advanced Database Administration" zu belegen. Dieser beruht vollständig auf den offiziellen Oracle Trainings-Unterlagen zur Prüfung in Oracle Administration und erlaubt daher die Teilnahme an der offiziellen Zertifizierung. Im Gegensatz zur SQL Prüfung, deren Inhalt man sich gut selbst aneignen kann, hilft bei der Administrator-Zertifizierung ein echter Kurs mit Seminar ungemein. Viele Konzepte lassen sich schwer aus einem Buch lernen. Die Bestandteile der SGA oder das Anlegen von Benutzern mögen leicht zugänglich sein, Redo- und Undo-Management sowie Backup und Recovery kann man nur verstehen, wenn man Beispiele hat und diese an einem Testsystem (keine "kleine" XE-Datenbank, sondern eine "richtige" Datenbank mit Enterprise Manager) ausprobieren kann. Übermäßig viel Zeit habe ich keinesfalls investiert, weil das Grundsystem sehr logisch ist. Für die weniger nachvollziehbaren Bereiche, besonders die neuen Features, habe ich mir Fachbegriffe auf Lernkarten geschrieben und die Trainingsunterlagen am System durchgespielt. Die Prüfung war für mich überraschend schwer, weil das einfache "Tagesgeschäft" deutlich unterrepräsentiert ist. In den Multiple-Choice-Fragen werden viele Besonderheiten und Use-Cases abgefragt (online findet man viele Beispielfragen). Da beide Tests in Englisch sind, sollte man nicht nur in der Terminologie des Oracle Datenbanksystems sondern auch in Fachbegriffen der Datenbankwelt allgemein bewandert sein. Oft machen einzelne Wörter (z.B. redundant oder synchronized, redo log oder redo log buffer) die richtige Antwort aus, ein signifikanter Anteil der Fragen beruht auf Zeichnungen oder Diagrammen, die beschrieben werden müssen. So muss man z.B. anhand eines Log-Auszugs beurteilen, warum die Datenbank nicht sauber geschlossen wurde. Allgemeines Wissen über Datenbanksysteme hilft leider nicht viel, da überproportional viele Fragen zu Oracle-spezifischen Themen gestellt werden, wie z.B. Optimierungs-Dienste (ADDM), Flashback, SQL Loader und ein wenig PL/SQL. Die SQL Prüfung ist dagegen sehr geradlinig - was aber nicht einfacher heißt. Hier kommt es mehr auf Auswendiglernen von Syntax an, was mir persönlich nicht liegt. Vor allem als Anwendungsprogrammierer kennt man oft proprietäre SQL-Funktionen nicht, es fällt schwer, sich einzelne Datumsberechnungsfunktionen, Typkonvertierungen, Namespaces oder krude Join-Methoden zu merken. Auf all dies wird in der Prüfung aber sehr viel Wert gelegt. Auch hier wird man wieder mit zweideutigen Multiple-Choice Fragen konfrontiert, bei denen sich z.B. nur die Reihenfolge der Parameter unterscheidet. Zudem sind die Parameter auch nicht ausgeschrieben, sondern in einem Entity-Relationship-Diagramm gegeben, wobei man auf die richtigen Datentypen achten muss. Mir persönlich war die Zeit fast zu knapp bemessen, weil man bei vielen Fragen erst ein Diagramm, einen Datenauszug oder einen längeren Text lesen muss, um dann die richtigen Statements zu finden. Hier helfen Lernkarten also nur bedingt - stattdessen üben, üben, üben. Durch den relativ niedrigen Pass-Score von 70% kann man es sich leisten, unsichere Fragen zuerst zu überspringen und erst nachdem alle sicheren beantwortet sind, zu überdenken. Die Prüfung ist auf jeden Fall fair. Ich habe durch das Oracle-Zertifizierungsprogramm viel gelernt. Die Datenbanken unter meiner Aufsicht laufen deutlich performanter und liefern höhere Verfügbarkeit, weil ich Probleme eliminieren konnte, die mir vorher nicht klar waren. Eine klassische Misskonfiguration, volle Archive Logs, weil diese mit zu lange gehaltenem Flashback-Speicher kollidieren, konnte ich bereits in einer der ersten Stunden meines Kurses an der Uni Melbourne mit Hilfe meines Professors klären. Beide Prüfungen waren problemlos parallel zu anderen Prüfungen zu absolvieren. Empfehlen kann ich eine gründliche Online-Recherche aber auch die Oracle Press-Bücher, welche mit Prüfungsfragen am Ende jedes Kapitels aufwarten. So spart man sich Zeit und ist trotzdem gut vorbereitet. Auch wenn ich keine Laufbahn als Administrator einschlagen werde, bin ich froh die zugrundeliegende Technologie vieler Anwendungen besser zu verstehen. Für meine tägliche Arbeit als Anwendungsentwickler hat es mir vor allem geholfen, Oracle-Konzepte z.B. im Bereich der Transaktionssteuerung und Wiederherstellung zu verstehen und damit viele Open Source Produkte jetzt sinnvoller bewerten und empfehlen zu können." Eine Übersicht der Zertifizierungspfade finden Sie auf der Oracle University Webseite (dann einfach "Deutschland""auswählen und anschließend auf den Punkt "Zertifizierungen" klicken).

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• Linux-Containers — Part 1: Overview

  - by Lenz Grimmer

  "Containers" by Jean-Pierre Martineau (CC BY-NC-SA 2.0). Linux Containers (LXC) provide a means to isolate individual services or applications as well as of a complete Linux operating system from other services running on the same host. To accomplish this, each container gets its own directory structure, network devices, IP addresses and process table. The processes running in other containers or the host system are not visible from inside a container. Additionally, Linux Containers allow for fine granular control of resources like RAM, CPU or disk I/O. Generally speaking, Linux Containers use a completely different approach than "classicial" virtualization technologies like KVM or Xen (on which Oracle VM Server for x86 is based on). An application running inside a container will be executed directly on the operating system kernel of the host system, shielded from all other running processes in a sandbox-like environment. This allows a very direct and fair distribution of CPU and I/O-resources. Linux containers can offer the best possible performance and several possibilities for managing and sharing the resources available. Similar to Containers (or Zones) on Oracle Solaris or FreeBSD jails, the same kernel version runs on the host as well as in the containers; it is not possible to run different Linux kernel versions or other operating systems like Microsoft Windows or Oracle Solaris for x86 inside a container. However, it is possible to run different Linux distribution versions (e.g. Fedora Linux in a container on top of an Oracle Linux host), provided it supports the version of the Linux kernel that runs on the host. This approach has one caveat, though - if any of the containers causes a kernel crash, it will bring down all other containers (and the host system) as well. For example, Oracle's Unbreakable Enterprise Kernel Release 2 (2.6.39) is supported for both Oracle Linux 5 and 6. This makes it possible to run Oracle Linux 5 and 6 container instances on top of an Oracle Linux 6 system. Since Linux Containers are fully implemented on the OS level (the Linux kernel), they can be easily combined with other virtualization technologies. It's certainly possible to set up Linux containers within a virtualized Linux instance that runs inside Oracle VM Server for Oracle VM Virtualbox. Some use cases for Linux Containers include: Consolidation of multiple separate Linux systems on one server: instances of Linux systems that are not performance-critical or only see sporadic use (e.g. a fax or print server or intranet services) do not necessarily need a dedicated server for their operations. These can easily be consolidated to run inside containers on a single server, to preserve energy and rack space. Running multiple instances of an application in parallel, e.g. for different users or customers. Each user receives his "own" application instance, with a defined level of service/performance. This prevents that one user's application could hog the entire system and ensures, that each user only has access to his own data set. It also helps to save main memory — if multiple instances of a same process are running, the Linux kernel can share memory pages that are identical and unchanged across all application instances. This also applies to shared libraries that applications may use, they are generally held in memory once and mapped to multiple processes. Quickly creating sandbox environments for development and testing purposes: containers that have been created and configured once can be archived as templates and can be duplicated (cloned) instantly on demand. After finishing the activity, the clone can safely be discarded. This allows to provide repeatable software builds and test environments, because the system will always be reset to its initial state for each run. Linux Containers also boot significantly faster than "classic" virtual machines, which can save a lot of time when running frequent build or test runs on applications. Safe execution of an individual application: if an application running inside a container has been compromised because of a security vulnerability, the host system and other containers remain unaffected. The potential damage can be minimized, analyzed and resolved directly from the host system. Note: Linux Containers on Oracle Linux 6 with the Unbreakable Enterprise Kernel Release 2 (2.6.39) are still marked as Technology Preview - their use is only recommended for testing and evaluation purposes. The Open-Source project "Linux Containers" (LXC) is driving the development of the technology behind this, which is based on the "Control Groups" (CGroups) and "Name Spaces" functionality of the Linux kernel. Oracle is actively involved in the Linux Containers development and contributes patches to the upstream LXC code base. Control Groups provide means to manage and monitor the allocation of resources for individual processes or process groups. Among other things, you can restrict the maximum amount of memory, CPU cycles as well as the disk and network throughput (in MB/s or IOP/s) that are available for an application. Name Spaces help to isolate process groups from each other, e.g. the visibility of other running processes or the exclusive access to a network device. It's also possible to restrict a process group's access and visibility of the entire file system hierarchy (similar to a classic "chroot" environment). CGroups and Name Spaces provide the foundation on which Linux containers are based on, but they can actually be used independently as well. A more detailed description of how Linux Containers can be created and managed on Oracle Linux will be explained in the second part of this article. Additional links related to Linux Containers: OTN Article: The Role of Oracle Solaris Zones and Linux Containers in a Virtualization Strategy Linux Containers on Wikipedia - Lenz Grimmer Follow me on: Personal Blog | Facebook | Twitter | Linux Blog |

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• CQRS &ndash; Questions and Concerns

  - by Dylan Smith

  I’ve been doing a lot of learning on CQRS and Event Sourcing over the last little while and I have a number of questions that I haven’t been able to answer. 1. What is the benefit of CQRS when compared to a typical DDD architecture that uses Event Sourcing and properly captures intent and behavior via verb-based commands? (other than Scalability) 2. When using CQRS what do you do with complex query-based logic? I’m going to elaborate on #1 in this blog post and I’ll do a follow-up post on #2. I watched through Greg Young’s video on the business benefits of CQRS + Event Sourcing and first let me say that I thought it was an excellent presentation that really drives home a lot of the benefits to this approach to architecture (I watched it twice in a row I enjoyed it so much!). But it didn’t answer some of my questions fully (I wish I had been there to ask these of Greg in person!). So let me pick apart some of the points he makes and how they relate to my first question above. I’m completely sold on the idea of event sourcing and have a clear understanding of the benefits that it brings to the table, so I’m not going to question that. But you can use event sourcing without going to a CQRS architecture, so my main question is around the benefits of CQRS + Event Sourcing vs Event Sourcing + Typical DDD architecture Architecture with Event Sourcing + Commands on Left, CQRS on Right Greg talks about how the stereotypical architecture doesn’t support DDD, but is that only because his diagram shows DTO’s coming up from the client. If we use the same diagram but allow the client to send commands doesn’t that remove a lot of the arguments that Greg makes against the stereotypical architecture? We can now introduce verbs into the system. We can capture intent now (storing it still requires event sourcing, but you can implement event sourcing without doing CQRS) We can create a rich domain model (as opposed to an anemic domain model) Scalability is obviously a benefit that CQRS brings to the table, but like Greg says, very few of the systems we create truly need significant scalability Greg talks about the ability to scale your development efforts. He says CQRS allows you to split the system into 3 parts (Client, Domain/Commands, Reads) and assign 3 teams of developers to work on them in parallel; letting you scale your development efforts by 3x with nearly linear gains. But in the stereotypical architecture don’t you already have 2 separate modules that you can split your dev efforts between: The client that sends commands/queries and receives DTO’s, and the Domain which accepts commands/queries, and generates events/DTO’s. If this is true it’s not really a 3x scaling you achieve with CQRS but merely a 1.5x scaling which while great doesn’t sound nearly as dramatic (“I can do it with 10 devs in 12 months – let me hire 5 more and we can have it done in 8 months”). Making the Query side “stupid simple” such that you can assign junior developers (or even outsource it) sounds like a valid benefit, but I have some concerns over what you do with complex query-based logic/behavior. I’m going to go into more detail on this in a follow-up blog post shortly. He also seemed to focus on how “stupid-simple” it is doing queries against the de-normalized data store, but I imagine there is still significant complexity in the event handlers that interpret the events and apply them to the de-normalized tables. It sounds like Greg suggests that because we’re doing CQRS that allows us to apply Event Sourcing when we otherwise wouldn’t be able to (~33:30 in the video). I don’t believe this is true. I don’t see why you wouldn’t be able to apply Event Sourcing without separating out the Commands and Queries. The queries would just operate against the domain model instead of the database. But you’d still get the benefits of Event Sourcing. Without CQRS the queries would only be able to operate against the current state rather than the event history, but even in CQRS the domain behaviors can only operate against the current state and I don’t see that being a big limiting factor. If some query needs to operate against something that is not captured by the current state you would just have to update the domain model to capture that information (no different than if that statement were made about a Command under CQRS). Some of the benefits I do see being applicable are that your domain model might end up being simpler/smaller since it only needs to represent the state needed to process commands and not worry about the reads (like the Deactivate Inventory Item and associated comment example that Greg provides). And also commands that can be handled in a Transaction Script style manner by the command handler simply generating events and not touching the domain model. It also makes it easier for your senior developers to focus on the command behavior and ignore the queries, which is usually going to be a better use of their time. And of course scalability. If anybody out there has any thoughts on this and can help educate me further, please either leave a comment or feel free to get in touch with me via email:

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• Parallelism in .NET – Part 17, Think Continuations, not Callbacks

  - by Reed

  In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

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• The Complementary Roles of PLM and PIM

  - by Ulf Köster

  Oracle Product Value Chain Solutions (aka Enterprise PLM Solutions) are a comprehensive set of product management solutions that work together to provide Oracle customers with a broad array of capabilities to manage all aspects of product life: innovation, design, launch, and supply chain / commercialization processes beyond the capabilities and boundaries of traditional engineering-focused Product Lifecycle Management applications. They support companies with an integrated managed view across the product value chain: From Lab to Launch, From Farm to Fork, From Concept to Product to Customer, From Product Innovation to Product Design and Product Commercialization. Product Lifecycle Management (PLM) represents a broad suite of software solutions to improve product-oriented business processes and data. PLM success stories prove that PLM helps companies improve time to market, increase product-related revenue, reduce product costs, reduce internal costs and improve product quality. As a maturing suite of enterprise solutions, PLM is still evolving to realize the promise it can provide across all facets of a business and all phases of the product lifecycle. The vision for PLM includes everything from gathering early requirements for a product through multiple stages of the product lifecycle from product design, through commercialization and eventual product retirement or replacement. In discrete or process industries, PLM is typically more focused on Product Definition as items with respect to the technical view of a material or part, including specifications, bills of material and manufacturing data. With Agile PLM, this is specifically related to capabilities addressing Product Collaboration, Governance and Compliance, Product Quality Management, Product Cost Management and Engineering Collaboration. PLM today is mainly addressing key requirements in the early product lifecycle, in engineering changes or in the “innovation cycle”, and primarily adds value related to product design, development, launch and engineering change process. In short, PLM is the master for Product Definition, wherever manufacturing takes place. Product Information Management (PIM) is a product suite that has evolved in parallel to PLM. Product Information Management (PIM) can extend the value of PLM implementations by providing complementary tools and capabilities. More relevant in the area of Product Commercialization, the vision for PIM is to manage product information throughout an enterprise and supply chain to improve product-related knowledge management, information sharing and synchronization from multiple data sources. PIM success stories have shown the ability to provide multiple benefits, with particular emphasis on reducing information complexity and information management costs. Product Information in PIM is typically treated as the commercial view of a material or part, including sales and marketing information and categorization. PIM collects information from multiple manufacturing sites and multiple suppliers into its repository, but also provides integration tools to push the information back out to the other systems, serving as an active central repository with the aim to provide a holistic view on any product sold by a company (hence the name “Product Hub”). In short, PIM is the master of commercial Product Information. So PIM is quickly becoming mandatory because of its value in optimizing multichannel selling processes and relationships with customers, as you can see from the following table: Viewpoint PLM Current State PIM Key Benefits PIM adds to PLM Product Lifecycle Primarily R&D Front end Innovation Cycle Change process Primarily commercial / transactional state of lifecycle Provides a seamless information flow from design and manufacturing through the ultimate selling and servicing of products Data Primarily focused on “item” vs. “product” data Product structures Specifications Technical information Repository for all product information. Reaches out to entire enterprise and its various silos of product information and descriptions Provides a “trusted source” of accurate product information to the internal organization and trading partners Data Lifecycle Repository for all design iterations Historical information Released, current information, with version management and time stamping Provides a single location to track and audit historical product information Communication PLM release finished product to ERP PLM is the master for Product Definition Captures information from disparate sources, including in-house data stores Recognizes the reality of today’s data “mess” across information silos Provides the ability to package product information to its audience in the desired, relevant format to meet their exacting business requirements Departmental R&D Manufacturing Quality Compliance Procurement Strategic Marketing Focus on Marketing and Sales Gathering information from other Departments, multiple sites, multiple suppliers A singular enterprise solution that leverages existing information silos and data stores Supply Chain Multi-site internal collaboration Supplier collaboration Customer collaboration Works with customers, exchanges / data pools, and trading partners to provide relevant product information packaged the way the customer desires Provides ability to provide trading partners and internal customers with information in a manner they desire, continuously Tools Data Management Collaboration Innovation Management Cleansing Synchronization Hub functions Consistent, clean and complete commercial product information The goals of both PLM and PIM, put simply, are to help companies make more profit from their products. PLM and PIM solutions can be easily added as they share some of the same goals, while coming from two different perspectives: the definition of the product and the commercialization of the product. Both can serve as a form of product “system of record”, but take different approaches to delivering value. Oracle Product Value Chain solutions offer rich new strategies for executives to collectively leverage Agile PLM, Product Data Hub, together with Enterprise Data Quality for Products, and other industry leading Oracle applications to achieve further incremental value, like Oracle Innovation Management. This is unique on the market today.

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• CQRS - Benefits

  - by Dylan Smith

  Thanks to all the comments and feedback from the last post I think I have a better understanding now of the benefits of CQRS (separate from the benefits of Event Sourcing). I’m going to try and sum it up here, and point out some areas where I could still use some advice: CQRS Benefits Sounds like the primary benefit of CQRS as an architecture is it allows you to create a simpler domain model by sucking out everything related to queries. I can definitely see the benefit to this, in general the domain logic related to commands is the high-value behavior in the software, but the logic required to service the queries would add a lot of low-value “noise” to the domain model that would dilute the high-value (command) behavior – sorting, paging, filtering, pre-fetch paths, etc. Also the most appropriate domain structure for implementing commands might not be the most optimal for implementing queries. To paraphrase Greg, this usually results in a domain model that is mediocre at both, piss-poor at one, or more likely piss-poor at both commands and queries. Not only will you be able to simplify your domain model by pulling out all the query logic, but at least a handful of commands in most systems will probably be “pass-though” type commands with little to no logic that just generate events. If these can be implemented directly in the command-handler and never touch the domain model, this allows you to slim down the domain model even more. Also, if you were to do event sourcing without CQRS, you no longer have a database containing the current state (only the domain model would) which makes it difficult (or impossible) to support ad-hoc querying and/or reporting that is common in most business software. Of course CQRS provides some great scalability benefits, not only scalability but I have to assume that it provides extremely low latency for most operations, especially if you have an asynchronous event bus. I know Greg says that you get a 3x scaling (Commands, Queries, Client) of your ability to perform parallel development, but IMHO, it seems like it only provides 1.5x scaling since even without CQRS you’re going to have your client loosely coupled to your domain - which is still a great benefit to be able to realize. Questions / Concerns If all the queries against an aggregate get pulled out to the Query layer, what if the only commands for that aggregate can be handled in a “pass-through” manner with the command handler directly generating events. Is it possible to have an aggregate that isn’t modeled in the domain model? Are there any issues or downsides to this? I know in the feedback from my previous posts it was suggested that having one domain model handling both commands and queries requires implementing a lot of traversals between objects that wouldn’t be necessary if it was only servicing commands. My question is, do you include traversals in your domain model based on the needs of the code, or based on the conceptual domain model? If none of my Commands require a Customer.Orders traversal, but the conceptual domain includes the concept of a set of orders belonging to a customer – should I model that in my domain model or not? I like the idea of using the Query side of the architecture as a place to put junior devs where the risk of them screwing something up has minimal impact. But I’m not sold on the idea that you can actually outsource it. Like I said in one of my comments on my previous post, the code to handle a query and generate DTO’s is going to be dead simple, but the code to process events and apply them to the tables on the query side is going to require a significant amount of domain knowledge to know which events to listen for to update each of the de-normalized tables (and what changes need to be made when each event is processed). I don’t know about everybody else, but having Indian/Russian/whatever outsourced developers have to do anything that requires significant domain knowledge has never been successful in my experience. And if you need to spec out for each new query which events to listen to and what to do with each one, well that’s probably going to be just as much work to document as it would be to just implement it. Greg made the point in a comment that doing an aggregate query like “Total Sales By Customer” is going to be inefficient if you use event sourcing but not CQRS. I don’t understand why that would be the case. I imagine in that case you’d simply have a method/property on the Customer object that calculated total sales for that customer by enumerating over the Orders collection. Then the application services layer would generate DTO’s off of the Customers collection that included say the CustomerID, CustomerName, TotalSales, or whatever the case may be. As long as you use a snapshotting implementation, I don’t see why that would be anymore inefficient in a DDD+Event Sourcing implementation than in a typical DDD implementation. Like I mentioned in my last post I still have some questions about query logic that haven’t been answered yet, but before I start asking those I want to make sure I have a strong grasp on what benefits CQRS provides.  My main concern with the query logic was that I know I could just toss it all into the query side, but I was concerned that I would be losing the benefits of using CQRS in the first place if I did that.  I want to elaborate more on this though with some example situations in an upcoming post.

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• Oracle Database 12c Spatial: Vector Performance Acceleration

  - by Okcan Yasin Saygili-Oracle

  Most business information has a location component, such as customer addresses, sales territories and physical assets. Businesses can take advantage of their geographic information by incorporating location analysis and intelligence into their information systems. This allows organizations to make better decisions, respond to customers more effectively, and reduce operational costs – increasing ROI and creating competitive advantage. Oracle Database, the industry’s most advanced database,  includes native location capabilities, fully integrated in the kernel, for fast, scalable, reliable and secure spatial and massive graph applications. It is a foundation for deploying enterprise-wide spatial information systems and locationenabled business applications. Developers can extend existing Oracle-based tools and applications, since they can easily incorporate location information directly in their applications, workflows, and services. Spatial Features The geospatial data features of Oracle Spatial and Graph option support complex geographic information systems (GIS) applications, enterprise applications and location services applications. Oracle Spatial and Graph option extends the spatial query and analysis features included in every edition of Oracle Database with the Oracle Locator feature, and provides a robust foundation for applications that require advanced spatial analysis and processing in the Oracle Database. It supports all major spatial data types and models, addressing challenging business-critical requirements from various industries, including transportation, utilities, energy, public sector, defense and commercial location intelligence. Network Data Model Graph Features The Network Data Model graph explicitly stores and maintains a persistent data model withnetwork connectivity and provides network analysis capability such as shortest path, nearest neighbors, within cost and reachability. It loads partitioned networks into memory on demand, overcomingthe limitations of in-memory analysis. Partitioning massive networks into manageable sub-networkssimplifies the network analysis. RDF Semantic Graph Features RDF Semantic Graph has native support for World Wide Web Consortium standards. It has open, scalable, and secure features for storing RDF/OWL ontologies anddata; native inference with OWL 2, SKOS and user-defined rules; and querying RDF/OWL data withSPARQL 1.1, Java APIs, and SPARQLgraph patterns in SQL. Video: Oracle Spatial and Graph Overview Oracle spatial is embeded on oracle database product. So ,we can use oracle installer (OUI).The Oracle Universal Installer (OUI) is used to install Oracle Database software. OUI is a graphical user interface utility that enables you to view the Oracle software that is installed on your machine, install new Oracle Database software, and delete Oracle software that you no longer need to use. Online Help is available to guide you through the installation process. One of the installation options is to create a database. If you select database creation, OUI automatically starts Oracle Database Configuration Assistant (DBCA) to guide you through the process of creating and configuring a database. If you do not create a database during installation, you must invoke DBCA after you have installed the software to create a database. You can also use DBCA to create additional databases. For installing Oracle Database 12c you may check the Installing Oracle Database Software and Creating a Database tutorial under the Oracle Database 12c 2-Day DBA Series.You can always check if spatial is available in your database using  "select comp_id, version, status, comp_name from dba_registry where comp_id='SDO';"   One of the most notable improvements with Oracle Spatial and Graph 12c can be seen in performance increases in vector data operations. Enabling the Spatial Vector Acceleration feature (available with the Spatial option) dramatically improves the performance of commonly used vector data operations, such as sdo_distance, sdo_aggr_union, and sdo_inside. With 12c, these operations also run more efficiently in parallel than in prior versions through the use of metadata caching. For organizations that have been facing processing limitations, these enhancements enable developers to make a small set of configuration changes and quickly realize significant performance improvements. Results include improved index performance, enhanced geometry engine performance, optimized secondary filter optimizations for Spatial operators, and improved CPU and memory utilization for many advanced vector functions. Vector performance acceleration is especially beneficial when using Oracle Exadata Database Machine and other large-scale systems. Oracle Spatial and Graph vector performance acceleration builds on general improvements available to all SDO_GEOMETRY operations in these areas: Caching of index metadata, Concurrent update mechanisms, and Optimized spatial predicate selectivity and cost functions. These optimizations enable more efficient use of: CPU, Memory, and Partitioning Resulting in substantial query performance improvements.UsageTo accelerate the performance of spatial operators, it is recommended that you set the SPATIAL_VECTOR_ACCELERATION database system parameter to the value TRUE. (This parameter is authorized for use only by licensed Oracle Spatial users, and its default value is FALSE.) You can set this parameter for the whole system or for a single session. To set the value for the whole system, do either of the following:Enter the following statement from a suitably privileged account:   ALTER SYSTEM SET SPATIAL_VECTOR_ACCELERATION = TRUE;Add the following to the database initialization file (xxxinit.ora):   SPATIAL_VECTOR_ACCELERATION = TRUE;To set the value for the current session, enter the following statement from a suitably privileged account:   ALTER SESSION SET SPATIAL_VECTOR_ACCELERATION = TRUE; Checkout the complete list of new features on Oracle.com @ http://www.oracle.com/technetwork/database/options/spatialandgraph/overview/index.html Spatial and Graph Data Sheet (PDF) Spatial and Graph White Paper (PDF)

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• CLR via C# 3rd Edition is out

  - by Abhijeet Patel

  Time for some book news update. CLR via C#, 3rd Edition seems to have been out for a little while now. The book was released in early Feb this year, and needless to say my copy is on it’s way. I can barely wait to dig in and chew on the goodies that one of the best technical authors and software professionals I respect has in store. The 2nd edition of the book was an absolute treat and this edition promises to be no less. Here is a brief description of what’s new and updated from the 2nd edition. Part I – CLR Basics Chapter 1-The CLR’s Execution Model Added about discussion about C#’s /optimize and /debug switches and how they relate to each other. Chapter 2-Building, Packaging, Deploying, and Administering Applications and Types Improved discussion about Win32 manifest information and version resource information. Chapter 3-Shared Assemblies and Strongly Named Assemblies Added discussion of TypeForwardedToAttribute and TypeForwardedFromAttribute. Part II – Designing Types Chapter 4-Type Fundamentals No new topics. Chapter 5-Primitive, Reference, and Value Types Enhanced discussion of checked and unchecked code and added discussion of new BigInteger type. Also added discussion of C# 4.0’s dynamic primitive type. Chapter 6-Type and Member Basics No new topics. Chapter 7-Constants and Fields No new topics. Chapter 8-Methods Added discussion of extension methods and partial methods. Chapter 9-Parameters Added discussion of optional/named parameters and implicitly-typed local variables. Chapter 10-Properties Added discussion of automatically-implemented properties, properties and the Visual Studio debugger, object and collection initializers, anonymous types, the System.Tuple type and the ExpandoObject type. Chapter 11-Events Added discussion of events and thread-safety as well as showing a cool extension method to simplify the raising of an event. Chapter 12-Generics Added discussion of delegate and interface generic type argument variance. Chapter 13-Interfaces No new topics. Part III – Essential Types Chapter 14-Chars, Strings, and Working with Text No new topics. Chapter 15-Enums Added coverage of new Enum and Type methods to access enumerated type instances. Chapter 16-Arrays Added new section on initializing array elements. Chapter 17-Delegates Added discussion of using generic delegates to avoid defining new delegate types. Also added discussion of lambda expressions. Chapter 18-Attributes No new topics. Chapter 19-Nullable Value Types Added discussion on performance. Part IV – CLR Facilities Chapter 20-Exception Handling and State Management This chapter has been completely rewritten. It is now about exception handling and state management. It includes discussions of code contracts and constrained execution regions (CERs). It also includes a new section on trade-offs between writing productive code and reliable code. Chapter 21-Automatic Memory Management Added discussion of C#’s fixed state and how it works to pin objects in the heap. Rewrote the code for weak delegates so you can use them with any class that exposes an event (the class doesn’t have to support weak delegates itself). Added discussion on the new ConditionalWeakTable class, GC Collection modes, Full GC notifications, garbage collection modes and latency modes. I also include a new sample showing how your application can receive notifications whenever Generation 0 or 2 collections occur. Chapter 22-CLR Hosting and AppDomains Added discussion of side-by-side support allowing multiple CLRs to be loaded in a single process. Added section on the performance of using MarshalByRefObject-derived types. Substantially rewrote the section on cross-AppDomain communication. Added section on AppDomain Monitoring and first chance exception notifications. Updated the section on the AppDomainManager class. Chapter 23-Assembly Loading and Reflection Added section on how to deploy a single file with dependent assemblies embedded inside it. Added section comparing reflection invoke vs bind/invoke vs bind/create delegate/invoke vs C#’s dynamic type. Chapter 24-Runtime Serialization This is a whole new chapter that was not in the 2nd Edition. Part V – Threading Chapter 25-Threading Basics Whole new chapter motivating why Windows supports threads, thread overhead, CPU trends, NUMA Architectures, the relationship between CLR threads and Windows threads, the Thread class, reasons to use threads, thread scheduling and priorities, foreground thread vs background threads. Chapter 26-Performing Compute-Bound Asynchronous Operations Whole new chapter explaining the CLR’s thread pool. This chapter covers all the new .NET 4.0 constructs including cooperative cancelation, Tasks, the aralle class, parallel language integrated query, timers, how the thread pool manages its threads, cache lines and false sharing. Chapter 27-Performing I/O-Bound Asynchronous Operations Whole new chapter explaining how Windows performs synchronous and asynchronous I/O operations. Then, I go into the CLR’s Asynchronous Programming Model, my AsyncEnumerator class, the APM and exceptions, Applications and their threading models, implementing a service asynchronously, the APM and Compute-bound operations, APM considerations, I/O request priorities, converting the APM to a Task, the event-based Asynchronous Pattern, programming model soup. Chapter 28-Primitive Thread Synchronization Constructs Whole new chapter discusses class libraries and thread safety, primitive user-mode, kernel-mode constructs, and data alignment. Chapter 29-Hybrid Thread Synchronization Constructs Whole new chapter discussion various hybrid constructs such as ManualResetEventSlim, SemaphoreSlim, CountdownEvent, Barrier, ReaderWriterLock(Slim), OneManyResourceLock, Monitor, 3 ways to solve the double-check locking technique, .NET 4.0’s Lazy and LazyInitializer classes, the condition variable pattern, .NET 4.0’s concurrent collection classes, the ReaderWriterGate and SyncGate classes.

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• Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

  - by dotneteer

  Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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• F# for the C# Programmer

  - by mbcrump

  Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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