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• JavaDay Taipei 2014 Trip Report

  - by reza_rahman

  JavaDay Taipei 2014 was held at the Taipei International Convention Center on August 1st. Organized by Oracle University, it is one of the largest Java developer events in Taiwan. This was another successful year for JavaDay Taipei with a fully sold out venue packed with youthful, energetic developers (this was my second time at the event and I have already been invited to speak again next year!). In addition to Oracle speakers like me, Steve Chin and Naveen Asrani, the event also featured a bevy of local speakers including Taipei Java community leaders. Topics included Java SE, Java EE, JavaFX, cloud and Big Data. It was my pleasure and privilege to present one of the opening keynotes for the event. I presented my session on Java EE titled "JavaEE.Next(): Java EE 7, 8, and Beyond". I covered the changes in Java EE 7 as well as what's coming in Java EE 8. I demoed the Cargo Tracker Java EE BluePrints. I also briefly talked about Adopt-a-JSR for Java EE 8. The slides for the keynote are below (click here to download and view the actual PDF): It appears your Web browser is not configured to display PDF files. No worries, just click here to download the PDF file. In the afternoon I did my JavaScript + Java EE 7 talk titled "Using JavaScript/HTML5 Rich Clients with Java EE 7". This talk is basically about aligning EE 7 with the emerging JavaScript ecosystem (specifically AngularJS). The talk was completely packed. The slide deck for the talk is here: JavaScript/HTML5 Rich Clients Using Java EE 7 from Reza Rahman The demo application code is posted on GitHub. The code should be a helpful resource if this development model is something that interests you. Do let me know if you need help with it but the instructions should be fairly self-explanatory. I am delivering this material at JavaOne 2014 as a two-hour tutorial. This should give me a little more bandwidth to dig a little deeper, especially on the JavaScript end. I finished off Java Day Taipei with my talk titled "Using NoSQL with ~JPA, EclipseLink and Java EE" (this was the last session of the conference). The talk covers an interesting gap that there is surprisingly little material on out there. The talk has three parts -- a birds-eye view of the NoSQL landscape, how to use NoSQL via a JPA centric facade using EclipseLink NoSQL, Hibernate OGM, DataNucleus, Kundera, Easy-Cassandra, etc and how to use NoSQL native APIs in Java EE via CDI. The slides for the talk are here: Using NoSQL with ~JPA, EclipseLink and Java EE from Reza Rahman The JPA based demo is available here, while the CDI based demo is available here. Both demos use MongoDB as the data store. Do let me know if you need help getting the demos up and running. After the event the Oracle University folks hosted a reception in the evening which was very well attended by organizers, speakers and local Java community leaders. I am extremely saddened by the fact that this otherwise excellent trip was scarred by terrible tragedy. After the conference I joined a few folks for a hike on the Maokong Mountain on Saturday. The group included friends in the Taiwanese Java community including Ian and Robbie Cheng. Without warning, fatal tragedy struck on a remote part of the trail. Despite best efforts by us, the excellent Taiwanese Emergency Rescue Team and World class Taiwanese physicians we were unable to save our friend Robbie Cheng's life. Robbie was just thirty-four years old and is survived by his younger brother, mother and father. Being the father of a young child myself, I can only imagine the deep sorrow that this senseless loss unleashes. Robbie was a key member of the Taiwanese Java community and a Java Evangelist at Sun at one point. Ironically the only picture I was able to take of the trail was mere moments before tragedy. I thought I should place him in that picture in profoundly respectful memoriam: Perhaps there is some solace in the fact that there is something inherently honorable in living a bright life, dying young and meeting one's end on a beautiful remote mountain trail few venture to behold let alone attempt to ascend in a long and tired lifetime. Perhaps I'd even say it's a fate I would not entirely regret facing if it were my own. With that thought in mind it seems appropriate to me to quote some lyrics from the song "Runes to My Memory" by legendary Swedish heavy metal band Amon Amarth idealizing a fallen Viking warrior cut down in his prime: "Here I lie on wet sand I will not make it home I clench my sword in my hand Say farewell to those I love When I am dead Lay me in a mound Place my weapons by my side For the journey to Hall up high When I am dead Lay me in a mound Raise a stone for all to see Runes carved to my memory" I submit my deepest condolences to Robbie's family and hope my next trip to Taiwan ends in a less somber note.

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• IE9, LightSwitch Beta 2 and Zune HD: A Study in Risk Management?

  - by andrewbrust

  Photo by parl, 'Risk.’ Under Creative Commons Attribution-NonCommercial-NoDerivs License This has been a busy week for Microsoft, and for me as well.  On Monday, Microsoft launched Internet Explorer 9 at South by Southwest (SXSW) in Austin, TX.  That evening I flew from New York to Seattle.  On Tuesday morning, Microsoft launched Visual Studio LightSwitch, Beta 2 with a Go-Live license, in Redmond, and I had the privilege of speaking at the keynote presentation where the announcement was made.  Readers of this blog know I‘m a fan of LightSwitch, so I was happy to tell the app dev tools partners in the audience that I thought the LightSwitch extensions ecosystem represented a big opportunity – comparable to the opportunity when Visual Basic 1.0 was entering its final beta roughly 20 years ago.  On Tuesday evening, I flew back to New York (and wrote most of this post in-flight). Two busy, productive days.  But there was a caveat that impacts the accomplishments, because Monday was also the day reports surfaced from credible news agencies that Microsoft was discontinuing its dedicated Zune hardware efforts.  While the Zune brand, technology and service will continue to be a component of Windows Phone and a piece of the Xbox puzzle as well, speculation is that Microsoft will no longer be going toe-to-toe with iPod touch in the portable music player market. If we take all three of these developments together (even if one of them is based on speculation), two interesting conclusions can reasonably be drawn, one good and one less so. Microsoft is doubling down on technologies it finds strategic and de-emphasizing those that it does not.  HTML 5 and the Web are strategic, so here comes IE9, and it’s a very good browser.  Try it and see.  Silverlight is strategic too, as is SQL Server, Windows Azure and SQL Azure, so here comes Visual Studio LightSwitch Beta 2 and a license to deploy its apps to production.  Downloads of that product have exceeded Microsoft’s projections by more than 50%, and the company is even citing analyst firms’ figures covering the number of power-user developers that might use it. (I happen to think the product will be used by full-fledged developers as well, but that’s a separate discussion.) Windows Phone is strategic too…I wasn’t 100% positive of that before, but the Nokia agreement has made me confident.  Xbox as an entertainment appliance is also strategic.  Standalone music players are not strategic – and even if they were, selling them has been a losing battle for Microsoft.  So if Microsoft has consolidated the Zune content story and the ZunePass subscription into Xbox and Windows Phone, it would make sense, and would be a smart allocation of resources.  Essentially, it would be for the greater good. But it’s not all good.  In this scenario, Zune player customers would lose out.  Unless they wanted to switch to Windows Phone, and then use their phone’s battery for the portable media needs, they’re going to need a new platform.  They’re going to feel abandoned.  Even if Zune lives, there have been other such cul de sacs for customers.  Remember SPOT watches?  Live Spaces?  The original Live Mesh?  Microsoft discontinued each of these products.  The company is to be commended for cutting its losses, as admitting a loss isn’t easy.  But Redmond won’t be well-regarded by the victims of those decisions.  Instead, it gets black marks. What’s the answer?  I think it’s a bit like the 1980’s New York City “don’t block the box” gridlock rules: don’t enter an intersection unless you see a clear path through it.  If the light turns red and you’re blocking the perpendicular traffic, that’s your fault in judgment.  You get fined and get points on your license and you don’t get to shrug it off as beyond your control.  Accountability is key.  The same goes for Microsoft.  If it decides to enter a market, it should see a reasonable path through success in that market. Switching analogies, Microsoft shouldn’t make investments haphazardly, and it certainly shouldn’t ask investors to buy into a high-risk fund that is sold as safe and which offers only moderate returns.  People won’t continue to invest with a fund manager with a track record of over-zealous, imprudent, sub-prime investments.  The same is true on the product side for Microsoft, and not just with music players and geeky wrist watches.  It’s true of Web browsers, and line-of-business app dev tools, and smartphones, and cloud platforms and operating systems too.  When Microsoft is casual about its own risk, it raises risk for its customers, and weakens its reputation, market share and credibility.  That doesn’t mean all risk is bad, but it does mean no product team’s risk should be taken lightly. For mutual fund companies, it’s the CEO’s job to give his fund managers autonomy, but to make sure they’re conforming to a standard of rational risk management.  Because all those funds carry the same brand, and many of them serve the same investors. The same goes for Microsoft, its product portfolio, its executive ranks and its product managers.

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• Which OAuth library do you find works best for Objective-C/iPhone?

  - by Brennan

  I have been looking to switch to OAuth for my Twitter integration code and now that there is a deadline in less than 7 weeks (see countdown link) it is even more important to make the jump to OAuth. I have been doing Basic Authentication which is extremely easy. Unfortunately OAuth does not appear to be something that I would whip together in a couple of hours. http://www.countdowntooauth.com/ So I am looking to use a library. I have put together the following list. MPOAuth MGTwitterEngine OAuthConsumer I see that MPOAuth has some great features with a good deal of testing code in place but there is one big problem. It does not work. The sample iPhone project that is supposed to authenticate with Twitter causes an error which others have identified and logged as a bug. http://code.google.com/p/mpoauthconnection/issues/detail?id=29 The last code change was March 11 and this bug was filed on March 30. It has been over a month and this critical bug has not been fixed yet. So I have moved on to MGTwitterEngine. I pulled down the source code and loaded it up in Xcode. Immediately I find that there are a few dependencies and the README file does not have a clear list of steps to fetch those dependencies and integrate them with the project so that it builds successfully. I see this as a sign that the project is not mature enough for prime time. I see also that the project references 2 libraries for JSON when one should be enough. One is TouchJSON which has worked well for me so I am again discouraged from relying on this project for my applications. I did find that MGTwitterEngine makes use of OAuthConsumer which is one of many OAuth projects hosted by an OAuth project on Google Code. http://code.google.com/p/oauth/ http://code.google.com/p/oauthconsumer/wiki/UsingOAuthConsumer It looks like OAuthConsumer is a good choice at first glance. It is hosted with other OAuth libraries and has some nice documentation with it. I pulled down the code and it builds without errors but it does have many warnings. And when I run the new Build and Analyze feature in Xcode 3.2 I see 50 analyzer results. Many are marked as potential memory leaks which would likely lead to instability in any app which uses this library. It seems there is no clear winner and I have to go with something before the big Twitter OAuth deadline. Any suggestions?

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• Miller-rabin exception number?

  - by nightcracker

  Hey everyone. This question is about the number 169716931325235658326303. According to http://www.alpertron.com.ar/ECM.HTM it is prime. According to my miller-rabin implementation in python with 7 repetitions is is composite. With 50 repetitions it is still composite. With 5000 repetitions it is STILL composite. I thought, this might be a problem of my implementation. So I tried GNU MP bignum library, which has a miller-rabin primality test built-in. I tested with 1000000 repetitions. Still composite. This is my implementation of the miller-rabin primality test: def isprime(n, precision=7): if n == 1 or n % 2 == 0: return False elif n < 1: raise ValueError("Out of bounds, first argument must be > 0") d = n - 1 s = 0 while d % 2 == 0: d //= 2 s += 1 for repeat in range(precision): a = random.randrange(2, n - 2) x = pow(a, d, n) if x == 1 or x == n - 1: continue for r in range(s - 1): x = pow(x, 2, n) if x == 1: return False if x == n - 1: break else: return False return True And the code for the GMP test: #include <gmp.h> #include <stdio.h> int main(int argc, char* argv[]) { mpz_t test; mpz_init_set_str(test, "169716931325235658326303", 10); printf("%d\n", mpz_probab_prime_p(test, 1000000)); mpz_clear(test); return 0; } As far as I know there are no "exceptions" (which return false positives for any amount of repetitions) to the miller-rabin primality test. Have I stumpled upon one? Is my computer broken? Is the Elliptic Curve Method wrong? What is happening here? EDIT I found the issue, which is http://www.alpertron.com.ar/ECM.HTM. I trusted this applet, I'll contact the author his applet's implementation of the ECM is faulty for this number. Thanks. EDIT2 Hah, the shame! In the end it was something that went wrong with copy/pasting on my side. NOR the applet NOR the miller-rabin algorithm NOR my implementation NOR gmp's implementation of it is wrong, the only thing that's wrong is me. I'm sorry.

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• Can GPU capabilities impact virtual machine performance?

  - by Dave White

  While this many not seem like a programming question directly, it impacts my development activities and so it seems like it belongs here. It seems that more and more developers are turning to virtual environments for development activities on their computers, SharePoint development being a prime example. Also, as a trainer, I have virtual training environments for all of the classes that I teach. I recently purchased a new Dell E6510 to travel around with. It has the i7 620M (Dual core, HyperThreaded cpu running at 2.66GHz) and 8 GB of memory. Reading the spec sheet, it sounded like it would be a great laptop to carry around and run virtual machines on. Getting the laptop though, I've been pretty disappointed with the user experience of developing in a virtual machine. Giving the Virtual Machine 4 GB of memory, it was slow and I could type complete sentences and watch the VM "catchup". My company has training laptops that we provide for our classes. They are Dell Precision M6400 Intel Core 2 Duo P8700 running at 2.54Ghz with 8 GB of memory and the experience on this laptops is night and day compared to the E6510. They are crisp and you barely aware that you are running in a virtual environment. Since the E6510 should be faster in all categories than the M6400, I couldn't understand why the new laptop was slower, so I did a component by component comparison and the only place where the E6510 is less performant than the M6400 is the graphics department. The M6400 is running a nVidia FX 2700m GPU and the E6510 is running a nVidia 3100M GPU. Looking at benchmarks of the two GPUs suggest that the FX 2700M is twice as fast as the 3100M. http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html 3100M = 111th (E6510) FX 2700m = 47th (Precision M6400) Radeon HD 5870 = 8th (Alienware) The host OS is Windows 7 64bit as is the guest OS, running in Virtual Box 3.1.8 with Guest Additions installed on the guest. The IDE being used in the virtual environment is VS 2010 Premium. So after that long setup, my question is: Is the GPU significantly impacting the virtual machine's performance or are there other factors that I'm not looking at that I can use to boost the vm's performance? Do we now have to consider GPU performance when purchasing laptops where we expect to use virtualized development environments? Thanks in advance. Cheers, Dave

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• Normalizing Item Names & Synonyms

  - by RabidFire

  Consider an e-commerce application with multiple stores. Each store owner can edit the item catalog of his store. My current database schema is as follows: item_names: id | name | description | picture | common(BOOL) items: id | item_name_id | picture | price | description | picture item_synonyms: id | item_name_id | name | error(BOOL) Notes: error indicates a wrong spelling (eg. "Ericson"). description and picture of the item_names table are "globals" that can optionally be overridden by "local" description and picture fields of the items table (in case the store owner wants to supply a different picture for an item). common helps separate unique item names ("Jimmy Joe's Cheese Pizza" from "Cheese Pizza") I think the bright side of this schema is: Optimized searching & Handling Synonyms: I can query the item_names & item_synonyms tables using name LIKE %QUERY% and obtain the list of item_name_ids that need to be joined with the items table. (Examples of synonyms: "Sony Ericsson", "Sony Ericson", "X10", "X 10") Autocompletion: Again, a simple query to the item_names table. I can avoid the usage of DISTINCT and it minimizes number of variations ("Sony Ericsson Xperia™ X10", "Sony Ericsson - Xperia X10", "Xperia X10, Sony Ericsson") The down side would be: Overhead: When inserting an item, I query item_names to see if this name already exists. If not, I create a new entry. When deleting an item, I count the number of entries with the same name. If this is the only item with that name, I delete the entry from the item_names table (just to keep things clean; accounts for possible erroneous submissions). And updating is the combination of both. Weird Item Names: Store owners sometimes use sentences like "Harry Potter 1, 2 Books + CDs + Magic Hat". There's something off about having so much overhead to accommodate cases like this. This would perhaps be the prime reason I'm tempted to go for a schema like this: items: id | name | picture | price | description | picture (... with item_names and item_synonyms as utility tables that I could query) Is there a better schema you would suggested? Should item names be normalized for autocomplete? Is this probably what Facebook does for "School", "City" entries? Is the first schema or the second better/optimal for search? Thanks in advance! References: (1) Is normalizing a person's name going too far?, (2) Avoiding DISTINCT

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• Simple RSA encryption (Java)

  - by jake blue

  This is simply for fun. This will not be used for any actual encryption. I'm only first year comp sci student and love cryptography. This took a long time to get working. At approximately N = 18, it begins breaking down. It won't encrypt messages properly after that point. I'm not sure why. Any insights? I'd also appreciate any links you could provide me to tutorials or interesting reading about Cryptography. import java.math.BigInteger; import java.security.SecureRandom; /** * Cryptography. * * Generates public and private keys used in encryption and * decryption * */ public class RSA { private final static BigInteger one = new BigInteger("1"); private final static SecureRandom random = new SecureRandom(); // prime numbers private BigInteger p; private BigInteger q; // modulus private BigInteger n; // totient private BigInteger t; // public key private BigInteger e; // private key private BigInteger d; private String cipherText; /** * Constructor for objects of class RSA */ public RSA(int N) { p = BigInteger.probablePrime(N/2, random); q = BigInteger.probablePrime(N/2, random); // initialising modulus n = p.multiply(q); // initialising t by euclid's totient function (p-1)(q-1) t = (p.subtract(one)).multiply(q.subtract(one)); // initialising public key ~ 65537 is common public key e = new BigInteger("65537"); } public int generatePrivateKey() { d = e.modInverse(t); return d.intValue(); } public String encrypt(String plainText) { String encrypted = ""; int j = 0; for(int i = 0; i < plainText.length(); i++){ char m = plainText.charAt(i); BigInteger bi1 = BigInteger.valueOf(m); BigInteger bi2 = bi1.modPow(e, n); j = bi2.intValue(); m = (char) j; encrypted += m; } cipherText = encrypted; return encrypted; } public String decrypt() { String decrypted = ""; int j = 0; for(int i = 0; i < cipherText.length(); i++){ char c = cipherText.charAt(i); BigInteger bi1 = BigInteger.valueOf(c); BigInteger bi2 = bi1.modPow(d, n); j = bi2.intValue(); c = (char) j; decrypted += c; } return decrypted; } }

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• get return value from 2 threads in C

  - by polslinux

  #include <stdio.h> #include <stdlib.h> #include <pthread.h> #include <stdint.h> #include <inttypes.h> typedef struct tmp_num{ int tmp_1; int tmp_2; }t_num; t_num t_nums; void *num_mezzo_1(void *num_orig); void *num_mezzo_2(void *num_orig); int main(int argc, char *argv[]){ pthread_t thread1, thread2; int tmp=0,rc1,rc2,num; num=atoi(argv[1]); if(num <= 3){ printf("Questo è un numero primo: %d\n", num); exit(0); } if( (rc1=pthread_create( &thread1, NULL, &num_mezzo_1, (void *)&num)) ){ printf("Creazione del thread fallita: %d\n", rc1); exit(1); } if( (rc2=pthread_create( &thread2, NULL, &num_mezzo_2, (void *)&num)) ){ printf("Creazione del thread fallita: %d\n", rc2); exit(1); } t_nums.tmp_1 = 0; t_nums.tmp_2 = 0; pthread_join(thread1, (void **)(&t_nums.tmp_1)); pthread_join(thread2, (void **)(&t_nums.tmp_2)); tmp=t_nums.tmp_1+t_nums.tmp_2; printf("%d %d %d\n", tmp, t_nums.tmp_1, t_nums.tmp_2); if(tmp>2){ printf("Questo NON è un numero primo: %d\n", num); } else{ printf("Questo è un numero primo: %d\n", num); } exit(0); } void *num_mezzo_1(void *num_orig){ int cont_1; int *n_orig=(int *)num_orig; t_nums.tmp_1 = 0; for(cont_1=1; cont_1<=(*n_orig/2); cont_1++){ if((*n_orig % cont_1) == 0){ (t_nums.tmp_1)++; } } pthread_exit((void *)(&t_nums.tmp_1)); return NULL; } void *num_mezzo_2(void *num_orig){ int cont_2; int *n_orig=(int *)num_orig; t_nums.tmp_2 = 0; for(cont_2=((*n_orig/2)+1); cont_2<=*n_orig; cont_2++){ if((*n_orig % cont_2) == 0){ (t_nums.tmp_2)++; } } pthread_exit((void *)(&t_nums.tmp_2)); return NULL; } How this program works: i have to input a number and this program will calculate if it is a prime number or not (i know that it is a bad algorithm but i only need to learn pthread). The problem is that the returned values are too much big.For example if i write "12" the value of tmp tmp_1 tmp_2 into the main are 12590412 6295204 6295208.Why i got those numbers??

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• dns queries not using nscd for caching

  - by xenoterracide

  I'm trying to use nscd (Nameservices Cache Daemon) to cache dns locally so I can stop using bind to do it. I've gotten it started and ntpd seems to attempt to use it. But everything else for hosts seems to ignore it. e.g if I do dig apache.org 3 times none of them will hit the cache. I'm viewing the cache stats using nscd -g to determine whether it's been used. I've also turned the debug log level up to see if I can see it hitting and the queries don't even hit nscd. nsswitch.conf # Begin /etc/nsswitch.conf passwd: files group: files shadow: files publickey: files hosts: cache files dns networks: files protocols: files services: files ethers: files rpc: files netgroup: files # End /etc/nsswitch.confenter code here nscd.conf # # /etc/nscd.conf # # An example Name Service Cache config file. This file is needed by nscd. # # Legal entries are: # # logfile <file> # debug-level <level> # threads <initial #threads to use> # max-threads <maximum #threads to use> # server-user <user to run server as instead of root> # server-user is ignored if nscd is started with -S parameters # stat-user <user who is allowed to request statistics> # reload-count unlimited|<number> # paranoia <yes|no> # restart-interval <time in seconds> # # enable-cache <service> <yes|no> # positive-time-to-live <service> <time in seconds> # negative-time-to-live <service> <time in seconds> # suggested-size <service> <prime number> # check-files <service> <yes|no> # persistent <service> <yes|no> # shared <service> <yes|no> # max-db-size <service> <number bytes> # auto-propagate <service> <yes|no> # # Currently supported cache names (services): passwd, group, hosts, services # logfile /var/log/nscd.log threads 4 max-threads 32 server-user nobody # stat-user somebody debug-level 9 # reload-count 5 paranoia no # restart-interval 3600 enable-cache passwd yes positive-time-to-live passwd 600 negative-time-to-live passwd 20 suggested-size passwd 211 check-files passwd yes persistent passwd yes shared passwd yes max-db-size passwd 33554432 auto-propagate passwd yes enable-cache group yes positive-time-to-live group 3600 negative-time-to-live group 60 suggested-size group 211 check-files group yes persistent group yes shared group yes max-db-size group 33554432 auto-propagate group yes enable-cache hosts yes positive-time-to-live hosts 3600 negative-time-to-live hosts 20 suggested-size hosts 211 check-files hosts yes persistent hosts yes shared hosts yes max-db-size hosts 33554432 enable-cache services yes positive-time-to-live services 28800 negative-time-to-live services 20 suggested-size services 211 check-files services yes persistent services yes shared services yes max-db-size services 33554432 resolv.conf # Generated by dhcpcd from eth0 nameserver 127.0.0.1 domain westell.com nameserver 192.168.1.1 nameserver 208.67.222.222 nameserver 208.67.220.220 as kind of a side note I'm using archlinux.

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• dns queries not using nscd for caching

  - by xenoterracide

  I'm trying to use nscd (Nameservices Cache Daemon) to cache dns locally so I can stop using bind to do it. I've gotten it started and ntpd seems to attempt to use it. But everything else for hosts seems to ignore it. e.g if I do dig apache.org 3 times none of them will hit the cache. I'm viewing the cache stats using nscd -g to determine whether it's been used. I've also turned the debug log level up to see if I can see it hitting and the queries don't even hit nscd. nsswitch.conf # Begin /etc/nsswitch.conf passwd: files group: files shadow: files publickey: files hosts: cache files dns networks: files protocols: files services: files ethers: files rpc: files netgroup: files # End /etc/nsswitch.confenter code here nscd.conf # # /etc/nscd.conf # # An example Name Service Cache config file. This file is needed by nscd. # # Legal entries are: # # logfile <file> # debug-level <level> # threads <initial #threads to use> # max-threads <maximum #threads to use> # server-user <user to run server as instead of root> # server-user is ignored if nscd is started with -S parameters # stat-user <user who is allowed to request statistics> # reload-count unlimited|<number> # paranoia <yes|no> # restart-interval <time in seconds> # # enable-cache <service> <yes|no> # positive-time-to-live <service> <time in seconds> # negative-time-to-live <service> <time in seconds> # suggested-size <service> <prime number> # check-files <service> <yes|no> # persistent <service> <yes|no> # shared <service> <yes|no> # max-db-size <service> <number bytes> # auto-propagate <service> <yes|no> # # Currently supported cache names (services): passwd, group, hosts, services # logfile /var/log/nscd.log threads 4 max-threads 32 server-user nobody # stat-user somebody debug-level 9 # reload-count 5 paranoia no # restart-interval 3600 enable-cache passwd yes positive-time-to-live passwd 600 negative-time-to-live passwd 20 suggested-size passwd 211 check-files passwd yes persistent passwd yes shared passwd yes max-db-size passwd 33554432 auto-propagate passwd yes enable-cache group yes positive-time-to-live group 3600 negative-time-to-live group 60 suggested-size group 211 check-files group yes persistent group yes shared group yes max-db-size group 33554432 auto-propagate group yes enable-cache hosts yes positive-time-to-live hosts 3600 negative-time-to-live hosts 20 suggested-size hosts 211 check-files hosts yes persistent hosts yes shared hosts yes max-db-size hosts 33554432 enable-cache services yes positive-time-to-live services 28800 negative-time-to-live services 20 suggested-size services 211 check-files services yes persistent services yes shared services yes max-db-size services 33554432 resolv.conf # Generated by dhcpcd from eth0 nameserver 127.0.0.1 domain westell.com nameserver 192.168.1.1 nameserver 208.67.222.222 nameserver 208.67.220.220 as kind of a side note I'm using archlinux.

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• Bind9 Debian Not responding

  - by Marc

  Im trying to set up a webserver with Bind9, apache2 on Debian 6. I am trying to learn to do it manualy so I do not have any control panels or anything just the command line. I have a domain name lets call it www.example.com I want a virtual host setup so that I can have multiple websites with different names on my server. I have ns1.example.com and ns2.example.com registered at my servers IP (123.456.789.12). Below is my Bind9 named.conf.options options { directory "/var/cache/bind"; // If there is a firewall between you and nameservers you want // to talk to, you may need to fix the firewall to allow multiple // ports to talk. See http://www.kb.cert.org/vuls/id/800113 // If your ISP provided one or more IP addresses for stable // nameservers, you probably want to use them as forwarders. // Uncomment the following block, and insert the addresses replacing // the all-0's placeholder. // forwarders { // 0.0.0.0; // }; auth-nxdomain no; # conform to RFC1035 listen-on-v6 { any; }; }; This is the default I'm not sure if i was supposed to edit it. I didn't. Here is my named.conf.default-zones: // prime the server with knowledge of the root servers zone "." { type hint; file "/etc/bind/db.root"; }; // be authoritative for the localhost forward and reverse zones, and for // broadcast zones as per RFC 1912 zone "localhost" { type master; file "/etc/bind/db.local"; }; zone "127.in-addr.arpa" { type master; file "/etc/bind/db.127"; }; zone "0.in-addr.arpa" { type master; file "/etc/bind/db.0"; }; zone "255.in-addr.arpa" { type master; file "/etc/bind/db.255"; }; zone "example.com.com" { type master; file "etc/bind/example.com.db"; }; named.conf.local Is an empty file with a comment saying to do local configuration here. example.com.db looks like this: ; BIND data file for mywebsite.com ; $ORIGIN example.com. $TTL 604800 @ IN SOA ns1.example.com. [email protected]. ( 2009120101 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; IN NS ns1.example.com. IN NS ns2.example.com. IN MX 10 mail.example.com. localhost IN A 127.0.0.1 example.com. IN A 123.456.789.12 ns1 IN A 123.456.789.12 ns2 IN A 123.456.789.12 www IN A 123.456.789.12 ftp IN A 123.456.789.12 mail IN A 123.456.789.12 boards IN CNAME www These are all settings I've found from various tutorials. Now when i go to intodns I get: You should already know that your NS records at your nameservers are missing, so here it is again: ns1.example.com ns2.example.com Can someone help me? I'm not sure what Im doing wrong.

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• Tailoring the Oracle Fusion Applications User Interface with Oracle Composer

  - by mvaughan

  By Killian Evers, Oracle Applications User Experience Changing the user interface (UI) is one of the most common modifications customers perform to Oracle Fusion Applications. Typically, customers add or remove a field based on their needs. Oracle makes the process of tailoring easier for customers, and reduces the burden for their IT staff, which you can read about on the Usable Apps website or in an earlier VoX post.This is the first in a series of posts that will talk about the tools that Oracle has provided for tailoring with its family of composers. These tools are designed for business systems analysts, and they allow employees other than IT staff to make changes in an upgrade-safe and patch-friendly manner. Let’s take a deep dive into one of these composers, the Oracle Composer. Oracle Composer allows business users to modify existing UIs after they have been deployed and are in use. It is an integral component of our SaaS offering. Using Oracle Composer, users can control:     •    Who sees the changes     •    When the changes are made     •    What changes are made Change for me, change for you, change for all of youOne of the most powerful aspects of Oracle Composer is its flexibility. Oracle uses Oracle Composer to make changes for a user or group of users – those who see the changes. A user of Oracle Fusion Applications can make changes to the user interface at runtime via Oracle Composer, and these changes will remain every time they log into the system. For example, they can rearrange certain objects on a page, add and remove designated content, and save queries.Business systems analysts can make changes to Oracle Fusion Application UIs for groups of users or all users. Oracle’s Fusion Middleware Metadata Services (MDS) stores these changes and retrieves them at runtime, merging customizations with the base metadata and revealing the final experience to the end user. A tailored application can have multiple customization layers, and some layers can be specific to certain Fusion Applications. Some examples of customization layers are: site, organization, country, or role. Customization layers are applied in a specific order of precedence on top of the base application metadata. This image illustrates how customization layers are applied.What time is it?Users make changes to UIs at design time, runtime, and design time at runtime. Design time changes are typically made by application developers using an integrated development environment, or IDE, such as Oracle JDeveloper. Once made, these changes are then deployed to managed servers by application administrators. Oracle Composer covers the other two areas: Runtime changes and design time at runtime changes. When we say users are making changes at runtime, we mean that the changes are made within the running application and take effect immediately in the running application. A prime example of this ability is users who make changes to their running application that only affect the UIs they see. What is new with Oracle Composer is the last area: Design time at runtime.  A business systems analyst can make changes to the UIs at runtime but does not have to make those changes immediately to the application. These changes are stored as metadata, separate from the base application definitions. Customizations made at runtime can be saved in a sandbox so that the changes can be isolated and validated before being published into an environment, without the need to redeploy the application. What can I do?Oracle Composer can be run in one of two modes. Depending on which mode is chosen, you may have different capabilities available for changing the UIs. The first mode is view mode, the most common default mode for most pages. This is the mode that is used for personalizations or user customizations. Users can access this mode via the Personalization link (see below) in the global region on Oracle Fusion Applications pages. In this mode, you can rearrange components on a page with drag-and-drop, collapse or expand components, add approved external content, and change the overall layout of a page. However, all of the changes made this way are exclusive to that particular user.The second mode, edit mode, is typically made available to select users with access privileges to edit page content. We call these folks business systems analysts. This mode is used to make UI changes for groups of users. Users with appropriate privileges can access the edit mode of Oracle Composer via the Administration menu (see below) in the global region on Oracle Fusion Applications pages. In edit mode, users can also add components, delete components, and edit component properties. While in edit mode in Oracle Composer, there are two views that assist the business systems analyst with making UI changes: Design View and Source View (see below). Design View, the default view, is a WYSIWYG rendering of the page and its content. The business systems analyst can perform these actions: Add content – including custom content like a portlet displaying news or stock quotes, or predefined content delivered from Oracle Fusion Applications (including ADF components and task flows) Rearrange content – performed via drag-and-drop on the page or by using the actions menu of a component or portlet to move content around Edit component properties and parameters – for specific components, control the visual properties such as text or display labels, or parameters such as RSS feeds Hide or show components – hidden components can be re-shown Delete components Change page layout – users can select from eight pre-defined layouts Edit page properties – create or edit a page’s parameters and display properties Reset page customizations – remove edits made to the page in the current layer and/or reset the page to a previous state. Detailed information on each of these capabilities and the additional actions not covered in the list above can be found in the Oracle® Fusion Middleware Developer's Guide for Oracle WebCenter.This image shows what the screen looks like in Design View.Source View, the second option in the edit mode of Oracle Composer, provides a WYSIWYG and a hierarchical rendering of page components in a component navigator. In Source View, users can access and modify properties of components that are not otherwise selectable in Design View. For example, many ADF Faces components can be edited only in Source View. Users can also edit components within a task flow. This image shows what the screen looks like in Source View.Detailed information on Source View can be found in the Oracle® Fusion Middleware Developer's Guide for Oracle WebCenter.Oracle Composer enables any application or portal to be customized or personalized after it has been deployed and is in use. It is designed to be extremely easy to use so that both business systems analysts and users can edit Oracle Fusion Applications pages with a few clicks of the mouse. Oracle Composer runs in all modern browsers and provides a rich, dynamic way to edit JSF application and portal pages.From the editor: The next post in this series about composers will be on Data Composer. You can also catch Killian speaking about extensibility at OpenWorld 2012 and in her Faces of Fusion video.

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• A Good Developer is So Hard to Find

  - by James Michael Hare

  Let me start out by saying I want to damn the writers of the Toughest Developer Puzzle Ever – 2. It is eating every last shred of my free time! But as I've been churning through each puzzle and marvelling at the brain teasers and trivia within, I began to think about interviewing developers and why it seems to be so hard to find good ones.  The problem is, it seems like no matter how hard we try to find the perfect way to separate the chaff from the wheat, inevitably someone will get hired who falls far short of expectations or someone will get passed over for missing a piece of trivia or a tricky brain teaser that could have been an excellent team member.   In shops that are primarily software-producing businesses or other heavily IT-oriented businesses (Microsoft, Amazon, etc) there often exists a much tighter bond between HR and the hiring development staff because development is their life-blood. Unfortunately, many of us work in places where IT is viewed as a cost or just a means to an end. In these shops, too often, HR and development staff may work against each other due to differences in opinion as to what a good developer is or what one is worth.  It seems that if you ask two different people what makes a good developer, often you will get three different opinions.   With the exception of those shops that are purely development-centric (you guys have it much easier!), most other shops have management who have very little knowledge about the development process.  Their view can often be that development is simply a skill that one learns and then once aquired, that developer can produce widgets as good as the next like workers on an assembly-line floor.  On the other side, you have many developers that feel that software development is an art unto itself and that the ability to create the most pure design or know the most obscure of keywords or write the shortest-possible obfuscated piece of code is a good coder.  So is it a skill?  An Art?  Or something entirely in between?   Saying that software is merely a skill and one just needs to learn the syntax and tools would be akin to saying anyone who knows English and can use Word can write a 300 page book that is accurate, meaningful, and stays true to the point.  This just isn't so.  It takes more than mere skill to take words and form a sentence, join those sentences into paragraphs, and those paragraphs into a document.  I've interviewed candidates who could answer obscure syntax and keyword questions and once they were hired could not code effectively at all.  So development must be more than a skill.   But on the other end, we have art.  Is development an art?  Is our end result to produce art?  I can marvel at a piece of code -- see it as concise and beautiful -- and yet that code most perform some stated function with accuracy and efficiency and maintainability.  None of these three things have anything to do with art, per se.  Art is beauty for its own sake and is a wonderful thing.  But if you apply that same though to development it just doesn't hold.  I've had developers tell me that all that matters is the end result and how you code it is entirely part of the art and I couldn't disagree more.  Yes, the end result, the accuracy, is the prime criteria to be met.  But if code is not maintainable and efficient, it would be just as useless as a beautiful car that breaks down once a week or that gets 2 miles to the gallon.  Yes, it may work in that it moves you from point A to point B and is pretty as hell, but if it can't be maintained or is not efficient, it's not a good solution.  So development must be something less than art.   In the end, I think I feel like development is a matter of craftsmanship.  We use our tools and we use our skills and set about to construct something that satisfies a purpose and yet is also elegant and efficient.  There is skill involved, and there is an art, but really it boils down to being able to craft code.  Crafting code is far more than writing code.  Anyone can write code if they know the syntax, but so few people can actually craft code that solves a purpose and craft it well.  So this is what I want to find, I want to find code craftsman!  But how?   I used to ask coding-trivia questions a long time ago and many people still fall back on this.  The thought is that if you ask the candidate some piece of coding trivia and they know the answer it must follow that they can craft good code.  For example:   What C++ keyword can be applied to a class/struct field to allow it to be changed even from a const-instance of that class/struct?  (answer: mutable)   So what do we prove if a candidate can answer this?  Only that they know what mutable means.  One would hope that this would infer that they'd know how to use it, and more importantly when and if it should ever be used!  But it rarely does!  The problem with triva questions is that you will either: Approve a really good developer who knows what some obscure keyword is (good) Reject a really good developer who never needed to use that keyword or is too inexperienced to know how to use it (bad) Approve a really bad developer who googled "C++ Interview Questions" and studied like hell but can't craft (very bad) Many HR departments love these kind of tests because they are short and easy to defend if a legal issue arrises on hiring decisions.  After all it's easy to say a person wasn't hired because they scored 30 out of 100 on some trivia test.  But unfortunately, you've eliminated a large part of your potential developer pool and possibly hired a few duds.  There are times I've hired candidates who knew every trivia question I could throw out them and couldn't craft.  And then there are times I've interviewed candidates who failed all my trivia but who I took a chance on who were my best finds ever.    So if not trivia, then what?  Brain teasers?  The thought is, these type of questions measure the thinking power of a candidate.  The problem is, once again, you will either: Approve a good candidate who has never heard the problem and can solve it (good) Reject a good candidate who just happens not to see the "catch" because they're nervous or it may be really obscure (bad) Approve a candidate who has studied enough interview brain teasers (once again, you can google em) to recognize the "catch" or knows the answer already (bad). Once again, you're eliminating good candidates and possibly accepting bad candidates.  In these cases, I think testing someone with brain teasers only tests their ability to answer brain teasers, not the ability to craft code. So how do we measure someone's ability to craft code?  Here's a novel idea: have them code!  Give them a computer and a compiler, or a whiteboard and a pen, or paper and pencil and have them construct a piece of code.  It just makes sense that if we're going to hire someone to code we should actually watch them code.  When they're done, we can judge them on several criteria: Correctness - does the candidate's solution accurately solve the problem proposed? Accuracy - is the candidate's solution reasonably syntactically correct? Efficiency - did the candidate write or use the more efficient data structures or algorithms for the job? Maintainability - was the candidate's code free of obfuscation and clever tricks that diminish readability? Persona - are they eager and willing or aloof and egotistical?  Will they work well within your team? It may sound simple, or it may sound crazy, but when I'm looking to hire a developer, I want to see them actually develop well-crafted code.

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• Elegance, thy Name is jQuery

  - by SGWellens

  So, I'm browsing though some questions over on the Stack Overflow website and I found a good jQuery question just a few minutes old. Here is a link to it. It was a tough question; I knew that by answering it, I could learn new stuff and reinforce what I already knew: Reading is good, doing is better. Maybe I could help someone in the process too. I cut and pasted the HTML from the question into my Visual Studio IDE and went back to Stack Overflow to reread the question. Dang, someone had already answered it! And it was a great answer. I never even had a chance to start analyzing the issue. Now I know what a one-legged man feels like in an ass-kicking contest. Nevertheless, since the question and answer were so interesting, I decided to dissect them and learn as much as possible. The HTML consisted of some divs separated by h3 headings.  Note the elements are laid out sequentially with no programmatic grouping: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div></form></body>  The requirement was to wrap a div around each h3 heading and the subsequent divs grouping them into sections. Why? I don't know, I suppose if you screen-scrapped some HTML from another site, you might want to reformat it before displaying it on your own. Anyways… Here is the marvelously, succinct posted answer: $('.heading').each(function(){ $(this).nextUntil('.heading').andSelf().wrapAll('<div class="section">');}); I was familiar with all the parts except for nextUntil and andSelf. But, I'll analyze the whole answer for completeness. I'll do this by rewriting the posted answer in a different style and adding a boat-load of comments: function Test(){ // $Sections is a jQuery object and it will contain three elements var $Sections = $('.heading'); // use each to iterate over each of the three elements $Sections.each(function () { // $this is a jquery object containing the current element // being iterated var $this = $(this); // nextUntil gets the following sibling elements until it reaches // an element with the CSS class 'heading' // andSelf adds in the source element (this) to the collection $this = $this.nextUntil('.heading').andSelf(); // wrap the elements with a div $this.wrapAll('<div class="section" >'); });}  The code here doesn't look nearly as concise and elegant as the original answer. However, unless you and your staff are jQuery masters, during development it really helps to work through algorithms step by step. You can step through this code in the debugger and examine the jQuery objects to make sure one step is working before proceeding on to the next. It's much easier to debug and troubleshoot when each logical coding step is a separate line of code. Note: You may think the original code runs much faster than this version. However, the time difference is trivial: Not enough to worry about: Less than 1 millisecond (tested in IE and FF). Note: You may want to jam everything into one line because it results in less traffic being sent to the client. That is true. However, most Internet servers now compress HTML and JavaScript by stripping out comments and white space (go to Bing or Google and view the source). This feature should be enabled on your server: Let the server compress your code, you don't need to do it. Free Career Advice: Creating maintainable code is Job One—Maximum Priority—The Prime Directive. If you find yourself suddenly transferred to customer support, it may be that the code you are writing is not as readable as it could be and not as readable as it should be. Moving on… I created a CSS class to enhance the results: .section{ background-color: yellow; border: 2px solid black; margin: 5px;} Here is the rendered output before:   …and after the jQuery code runs.   Pretty Cool! But, while playing with this code, the logic of nextUntil began to bother me: What happens in the last section? What stops elements from being collected since there are no more elements with the .heading class? The answer is nothing.  In this case it stopped collecting elements because it was at the end of the page.  But what if there were additional HTML elements? I added an anchor tag and another div to the HTML: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div><a>this is a link</a><div>unrelated div</div> </form></body> The code as-is will include both the anchor and the unrelated div. This isn't what we want.   My first attempt to correct this used the filter parameter of the nextUntil function: nextUntil('.heading', 'div')  This will only collect div elements. But it merely skipped the anchor tag and it still collected the unrelated div:   The problem is we need a way to tell the nextUntil function when to stop. CSS selectors to the rescue! nextUntil('.heading, a')  This tells nextUntil to stop collecting elements when it gets to an element with a .heading class OR when it gets to an anchor tag. In this case it solved the problem. FYI: The comma operator in a CSS selector allows multiple criteria.   Bingo! One final note, we could have broken the code down even more: We could have replaced the andSelf function here: $this = $this.nextUntil('.heading, a').andSelf(); With this: // get all the following siblings and then add the current item$this = $this.nextUntil('.heading, a');$this.add(this);  But in this case, the andSelf function reads real nice. In my opinion. Here's a link to a jsFiddle if you want to play with it. I hope someone finds this useful Steve Wellens CodeProject

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• Finally, upgrade from Nokia X3 to Samsung Galaxy S III

  This time, something slightly different but nonetheless not less interesting, hopefully. Living on a remote island like Mauritius, ill-praised 'Cyber Island' in the Indian Ocean, has its advantages in life style and relaxed environment to life in but in terms of technological aspects it can be quite a nightmare. Well, I guess this might be different story to report about... one day. Cyber Island Mauritius Despite it's shiny advertisement as Cyber Island and business in ICT hub to Africa, Mauritius is not on the latest track of available models in computer hardware or, in the context of this article, cellulars or smart-phone, or communication technology in general. Okay, I have to admit that this statement is only partly true. Money can buy, even here in Mauritius. Luckily, there are ways and ways to deal with this outcry of modern, read: technological, civilisation issues. Online shopping you might think? Yes, for sure, until you discover in your checkout procedure that a small island in the Indian Ocean isn't a preferred destination for delivery and the precious time you spent on putting your items into your cart and feeding your personal level of anticipation gets ruined on the last stint. Ordering from abroad saves you money Anyway, I got in touch with my personal courier and luckily there were some extra-kilos left in the luggage. First obstacle sorted, we have a Transporter! Okay, on the next occasion off to Amazon online and using their Prime service for fast delivery. Actually, the order was placed on Saturday evening and everything got delivered on Tuesday morning - nice job in less than 72 hours. Okay, among the items of that shopping rush I ordered a shiny Samsung Galaxy S III 16GB in oceanic blue - did I mention, that you hardly get a blue model in Mauritius? - for my BWE. Interesting side-notes: First, Amazon Germany dropped the prices for roughly 30% on the S3, and we got the 16GB model for less than 500 Euro (or approx. Rs. 19.500,-) compared to the usual Rs. 27.000,- on the local market. It even varies whether the local price is inclusive or exclusive VAT (15%). Second, since a while she was bothering me to get an iPhone and an iPad for her, fair enough I thought, decent hardware, posh design and reliable services. Until we watched the 'magical' introduction of Samsung's new models at the IFA exhibition, she read the bashing comments on Google+ on the iPhone 5 and I gave her a brief summary on the law suit between Apple and Samsung in the USA. So, yes, Samsung USA is right, the next big thing is already here - literally. My BWE loves the look and touch of the Galaxy S3. And for me it was more cost-effective in terms of purchases done at the App Store, ups, Play Store. Transfer of contacts, text messages and media files Okay, now that the hardware is in place, how to transfer all those contacts, text messages, media files, etc. between those two devices? In the past, I used to use the Nokia Communication Suite between various models but now for Android? Well, as usual Google and Bing are reliable friends and among the first hits I came across an article about How to Transfer Contacts from Nokia to Android. Couldn't be easier, right? Well, sort of... my main Windows systems are already running on Windows 8, and this actually caused problems with the mobile/smart-phone device drivers. The article provides the download for an older version 1.10 which upgrades to 2.11 (as time of writing this entry) but both couldn't get the Galaxy S3 and the Nokia connected. Shame on me... the product page clearly doesn't mention Windows 8 (for now) and Windows 8 isn't available for the general audience at all... After I took a spare machine running on Windows Vista everything went smooth. Software installed, upgrade done, device drivers for Android automatically downloaded and installed, and the same painless routine for the Nokia part. I think, I rebooted the system twice during the whole setup procedure but hey, it was more or less a distraction while coding some stuff in ASP.NET MVC and Telerik Kendo UI. The transfer of contacts and text messages was done via Wondershare MobileGo for Android, and all media files by moving the additional microSD card from one device to the other. But even without an external SD card, it would have been very easy to copy the files via Windows Explorer directly. Little catch and excellent service Fine, we are almost done and the only step left is to shift the SIM card... Ouch, gotcha! The X3 uses a standard size SIM card while the S III only accepts microSIM form factor. What an irony, bigger smartphone needs smaller SIM card. Luckily, the next showroom of Emtel is just 5 mins away up the road, and the service staff over there know their job. Finally, after roughly 10 mins of paper work, activation and small chit-chat, the S3 came to life on the mobile network. Owning a smart-phone now and knowing that my BWE would like to interact more on social networks away from home, especially to upload pictures and provide local 'check-ins', I activated a data package for her in advance, too. Even that it is Saturday, everything was already done and ready to be used. Nice bonus: The Emtel clerk directly offered me to set up the configuration for the Emtel data services, yes sure, go ahead, this saves me to search for that in the settings. Okay, spoiler-alert here, setting a static APN to access the Emtel network and the internet wouldn't be a challenge. But hey, she already had the phone in her hands and I could keep my eyes on the children. Well done, Emtel! Resume Thanks to the useful software package by Wondershare is was a hands-free experience to transfer all the data from a Nokia mobile on Symbian S60 to a Samsung Galaxy S III on Android Ice Cream Sandwich (ICS). In the future, this wont be a serious issue at all anymore thanks to synchronisation services and cloud storage. And for now, I'm only waiting for the official upgrades for Jelly Bean.

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• Elegance, thy Name is jQuery

  - by SGWellens

  So, I'm browsing though some questions over on the Stack Overflow website and I found a good jQuery question just a few minutes old. Here is a link to it. It was a tough question; I knew that by answering it, I could learn new stuff and reinforce what I already knew: Reading is good, doing is better. Maybe I could help someone in the process too. I cut and pasted the HTML from the question into my Visual Studio IDE and went back to Stack Overflow to reread the question. Dang, someone had already answered it! And it was a great answer. I never even had a chance to start analyzing the issue. Now I know what a one-legged man feels like in an ass-kicking contest. Nevertheless, since the question and answer were so interesting, I decided to dissect them and learn as much as possible. The HTML consisted of some divs separated by h3 headings.  Note the elements are laid out sequentially with no programmatic grouping: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div></form></body>  The requirement was to wrap a div around each h3 heading and the subsequent divs grouping them into sections. Why? I don't know, I suppose if you screen-scrapped some HTML from another site, you might want to reformat it before displaying it on your own. Anyways… Here is the marvelously, succinct posted answer: $('.heading').each(function(){ $(this).nextUntil('.heading').andSelf().wrapAll('<div class="section">');}); I was familiar with all the parts except for nextUntil and andSelf. But, I'll analyze the whole answer for completeness. I'll do this by rewriting the posted answer in a different style and adding a boat-load of comments: function Test(){ // $Sections is a jQuery object and it will contain three elements var $Sections = $('.heading'); // use each to iterate over each of the three elements $Sections.each(function () { // $this is a jquery object containing the current element // being iterated var $this = $(this); // nextUntil gets the following sibling elements until it reaches // an element with the CSS class 'heading' // andSelf adds in the source element (this) to the collection $this = $this.nextUntil('.heading').andSelf(); // wrap the elements with a div $this.wrapAll('<div class="section" >'); });}  The code here doesn't look nearly as concise and elegant as the original answer. However, unless you and your staff are jQuery masters, during development it really helps to work through algorithms step by step. You can step through this code in the debugger and examine the jQuery objects to make sure one step is working before proceeding on to the next. It's much easier to debug and troubleshoot when each logical coding step is a separate line. Note: You may think the original code runs much faster than this version. However, the time difference is trivial: Not enough to worry about: Less than 1 millisecond (tested in IE and FF). Note: You may want to jam everything into one line because it results in less traffic being sent to the client. That is true. However, most Internet servers now compress HTML and JavaScript by stripping out comments and white space (go to Bing or Google and view the source). This feature should be enabled on your server: Let the server compress your code, you don't need to do it. Free Career Advice: Creating maintainable code is Job One—Maximum Priority—The Prime Directive. If you find yourself suddenly transferred to customer support, it may be that the code you are writing is not as readable as it could be and not as readable as it should be. Moving on… I created a CSS class to see the results: .section{ background-color: yellow; border: 2px solid black; margin: 5px;} Here is the rendered output before:   …and after the jQuery code runs.   Pretty Cool! But, while playing with this code, the logic of nextUntil began to bother me: What happens in the last section? What stops elements from being collected since there are no more elements with the .heading class? The answer is nothing.  In this case it stopped because it was at the end of the page.  But what if there were additional HTML elements? I added an anchor tag and another div to the HTML: <h3 class="heading">Heading 1</h3> <div>Content</div> <div>More content</div> <div>Even more content</div><h3 class="heading">Heading 2</h3> <div>some content</div> <div>some more content</div><h3 class="heading">Heading 3</h3> <div>other content</div><a>this is a link</a><div>unrelated div</div> </form></body> The code as-is will include both the anchor and the unrelated div. This isn't what we want.   My first attempt to correct this used the filter parameter of the nextUntil function: nextUntil('.heading', 'div')  This will only collect div elements. But it merely skipped the anchor tag and it still collected the unrelated div:   The problem is we need a way to tell the nextUntil function when to stop. CSS selectors to the rescue: nextUntil('.heading, a')  This tells nextUntil to stop collecting sibling elements when it gets to an element with a .heading class OR when it gets to an anchor tag. In this case it solved the problem. FYI: The comma operator in a CSS selector allows multiple criteria.   Bingo! One final note, we could have broken the code down even more: We could have replaced the andSelf function here: $this = $this.nextUntil('.heading, a').andSelf(); With this: // get all the following siblings and then add the current item$this = $this.nextUntil('.heading, a');$this.add(this);  But in this case, the andSelf function reads real nice. In my opinion. Here's a link to a jsFiddle if you want to play with it. I hope someone finds this useful Steve Wellens CodeProject

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• Christmas in the Clouds

  - by andrewbrust

  I have been spending the last 2 weeks immersing myself in a number of Windows Azure and SQL Azure technologies.  And in setting up a new business (I’ll speak more about that in the future), I have also become a customer of Microsoft’s BPOS (Business Productivity Online Services).  In short, it has been a fortnight of Microsoft cloud computing. On the Azure side, I’ve looked, of course, at Web Roles and Worker Roles.  But I’ve also looked at Azure Storage’s REST API (including coding to it directly), I’ve looked at Azure Drive and the new VM Role; I’ve looked quite a bit at SQL Azure (including the project “Houston” Silverlight UI) and I’ve looked at SQL Azure labs’ OData service too. I’ve also looked at DataMarket and its integration with both PowerPivot and native Excel.  Then there’s AppFabric Caching, SQL Azure Reporting (what I could learn of it) and the Visual Studio tooling for Azure, including the storage of certificate-based credentials.  And to round it out with some user stuff, on the BPOS side, I’ve been working with Exchange Online, SharePoint Online and LiveMeeting. I have to say I like a lot of what I’ve been seeing.  Azure’s not perfect, and BPOS certainly isn’t either.  But there’s good stuff in all these products, and there’s a lot of value. Azure Goes Deep Most people know that Web and Worker roles put the platform in charge of spinning virtual machines up and down, and keeping them up to date. But you can go way beyond that now.  The still-in-beta VM Role gives you the power to craft the machine (much as does Amazon’s EC2), though it takes away the platform’s self-managing attributes.  It still spins instances up and down, making drive storage non-durable, but Azure Drive gives you the ability to store VHD files as blobs and mount them as virtual hard drives that are readable and writeable.  Whether with Azure Storage or SQL Azure, Azure does data.  And OData is everywhere.  Azure Table Storage supports an OData Interface.  So does SQL Azure and so does DataMarket (the former project “Dallas”).  That means that Azure data repositories aren’t just straightforward to provision and configure…they’re also easy to program against, from just about any programming environment, in a RESTful manner.  And for more .NET-centric implementations, Azure AppFabric caching takes the technology formerly known as “Velocity” and throws it up into the cloud, speeding data access even more. Snapping in Place Once you get the hang of it, this stuff just starts to work in a way that becomes natural to understand.  I wasn’t expecting that, and I was really happy to discover it. In retrospect, I am not surprised, because I think the various Azure teams are the center of gravity for Redmond’s innovation right now.  The products belie this and so do my observations of the product teams’ motivation and high morale.  It is really good to see this; Microsoft needs to lead somewhere, and they need to be seen as the underdog while doing so.  With Azure, both requirements are in place.   BPOS: Bad Acronym, Easy Setup BPOS is about products you already know; Exchange, SharePoint, Live Meeting and Office Communications Server.  As such, it’s hard not to be underwhelmed by BPOS.  Until you realize how easy it makes it to get all that stuff set up.  I would say that from sign-up to productive use took me about 45 minutes…and that included the time necessary to wrestle with my DNS provider, set up Outlook and my SmartPhone up to talk to the Exchange account, create my SharePoint site collection, and configure the Outlook Conferencing add-in to talk to the provisioned Live Meeting account. Never before did I think setting up my own Exchange mail could come anywhere close to the simplicity of setting up an SMTP/POP account, and yet BPOS actually made it faster.   What I want from my Azure Christmas Next Year Not everything about Microsoft’s cloud is good.  I close this post with a list of things I’d like to see addressed: BPOS offerings are still based on the 2007 Wave of Microsoft server technologies.  We need to get to 2010, and fast.  Arguably, the 2010 products should have been released to the off-premises channel before the on-premise sone.  Office 365 can’t come fast enough. Azure’s Internet tooling and domain naming, is scattered and confusing.  Deployed ASP.NET applications go to cloudapp.net; SQL Azure and Azure storage work off windows.net.  The Azure portal and Project Houston are at azure.com.  Then there’s appfabriclabs.com and sqlazurelabs.com.  There is a new Silverlight portal that replaces most, but not all of the HTML ones.  And Project Houston is Silvelright-based too, though separate from the Silverlight portal tooling. Microsoft is the king off tooling.  They should not make me keep an entire OneNote notebook full of portal links, account names, access keys, assemblies and namespaces and do so much CTRL-C/CTRL-V work.  I’d like to see more project templates, have them automatically reference the appropriate assemblies, generate the right using/Imports statements and prime my config files with the right markup.  Then I want a UI that lets me log in with my Live ID and pick the appropriate project, database, namespace and key string to get set up fast. Beta programs, if they’re open, should onboard me quickly.  I know the process is difficult and everyone’s going as fast as they can.  But I don’t know why it’s so difficult or why it takes so long.  Getting developers up to speed on new features quickly helps popularize the platform.  Make this a priority. Make Azure accessible from the simplicity platforms, i.e. ASP.NET Web Pages (Razor) and LightSwitch.  Support .NET 4 now.  Make WebMatrix, IIS Express and SQL Compact work with the Azure development fabric. Have HTML helpers make Azure programming easier.  Have LightSwitch work with SQL Azure and not require SQL Express.  LightSwitch has some promising Azure integration now.  But we need more.  WebMatrix has none and that’s just silly, now that the Extra Small Instance is being introduced. The Windows Azure Platform Training Kit is great.  But I want Microsoft to make it even better and I want them to evangelize it much more aggressively.  There’s a lot of good material on Azure development out there, but it’s scattered in the same way that the platform is.   The Training Kit ties a lot of disparate stuff together nicely.  Make it known. Should Old Acquaintance Be Forgot All in all, diving deep into Azure was a good way to end the year.  Diving deeper into Azure should a great way to spend next year, not just for me, but for Microsoft too.

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• Finally, upgrade from Nokia X3 to Samsung Galaxy S III

  This time, something slightly different but nonetheless not less interesting, hopefully. Living on a remote island like Mauritius, ill-praised 'Cyber Island' in the Indian Ocean, has its advantages in life style and relaxed environment to life in but in terms of technological aspects it can be quite a nightmare. Well, I guess this might be different story to report about... one day. Cyber Island Mauritius Despite it's shiny advertisement as Cyber Island and business in ICT hub to Africa, Mauritius is not on the latest track of available models in computer hardware or, in the context of this article, cellulars or smart-phone, or communication technology in general. Okay, I have to admit that this statement is only partly true. Money can buy, even here in Mauritius. Luckily, there are ways and ways to deal with this outcry of modern, read: technological, civilisation issues. Online shopping you might think? Yes, for sure, until you discover in your checkout procedure that a small island in the Indian Ocean isn't a preferred destination for delivery and the precious time you spent on putting your items into your cart and feeding your personal level of anticipation gets ruined on the last stint. Ordering from abroad saves you money Anyway, I got in touch with my personal courier and luckily there were some extra-kilos left in the luggage. First obstacle sorted, we have a Transporter! Okay, on the next occasion off to Amazon online and using their Prime service for fast delivery. Actually, the order was placed on Saturday evening and everything got delivered on Tuesday morning - nice job in less than 72 hours. Okay, among the items of that shopping rush I ordered a shiny Samsung Galaxy S III 16GB in oceanic blue - did I mention, that you hardly get a blue model in Mauritius? - for my BWE. Interesting side-notes: First, Amazon Germany dropped the prices for roughly 30% on the S3, and we got the 16GB model for less than 500 Euro (or approx. Rs. 19.500,-) compared to the usual Rs. 27.000,- on the local market. It even varies whether the local price is inclusive or exclusive VAT (15%). Second, since a while she was bothering me to get an iPhone and an iPad for her, fair enough I thought, decent hardware, posh design and reliable services. Until we watched the 'magical' introduction of Samsung's new models at the IFA exhibition, she read the bashing comments on Google+ on the iPhone 5 and I gave her a brief summary on the law suit between Apple and Samsung in the USA. So, yes, Samsung USA is right, the next big thing is already here - literally. My BWE loves the look and touch of the Galaxy S3. And for me it was more cost-effective in terms of purchases done at the App Store, ups, Play Store. Transfer of contacts, text messages and media files Okay, now that the hardware is in place, how to transfer all those contacts, text messages, media files, etc. between those two devices? In the past, I used to use the Nokia Communication Suite between various models but now for Android? Well, as usual Google and Bing are reliable friends and among the first hits I came across an article about How to Transfer Contacts from Nokia to Android. Couldn't be easier, right? Well, sort of... my main Windows systems are already running on Windows 8, and this actually caused problems with the mobile/smart-phone device drivers. The article provides the download for an older version 1.10 which upgrades to 2.11 (as time of writing this entry) but both couldn't get the Galaxy S3 and the Nokia connected. Shame on me... the product page clearly doesn't mention Windows 8 (for now) and Windows 8 isn't available for the general audience at all... After I took a spare machine running on Windows Vista everything went smooth. Software installed, upgrade done, device drivers for Android automatically downloaded and installed, and the same painless routine for the Nokia part. I think, I rebooted the system twice during the whole setup procedure but hey, it was more or less a distraction while coding some stuff in ASP.NET MVC and Telerik Kendo UI. The transfer of contacts and text messages was done via Wondershare MobileGo for Android, and all media files by moving the additional microSD card from one device to the other. But even without an external SD card, it would have been very easy to copy the files via Windows Explorer directly. Little catch and excellent service Fine, we are almost done and the only step left is to shift the SIM card... Ouch, gotcha! The X3 uses a standard size SIM card while the S III only accepts microSIM form factor. What an irony, bigger smartphone needs smaller SIM card. Luckily, the next showroom of Emtel is just 5 mins away up the road, and the service staff over there know their job. Finally, after roughly 10 mins of paper work, activation and small chit-chat, the S3 came to life on the mobile network. Owning a smart-phone now and knowing that my BWE would like to interact more on social networks away from home, especially to upload pictures and provide local 'check-ins', I activated a data package for her in advance, too. Even that it is Saturday, everything was already done and ready to be used. Nice bonus: The Emtel clerk directly offered me to set up the configuration for the Emtel data services, yes sure, go ahead, this saves me to search for that in the settings. Okay, spoiler-alert here, setting a static APN to access the Emtel network and the internet wouldn't be a challenge. But hey, she already had the phone in her hands and I could keep my eyes on the children. Well done, Emtel! Resume Thanks to the useful software package by Wondershare is was a hands-free experience to transfer all the data from a Nokia mobile on Symbian S60 to a Samsung Galaxy S III on Android Ice Cream Sandwich (ICS). In the future, this wont be a serious issue at all anymore thanks to synchronisation services and cloud storage. And for now, I'm only waiting for the official upgrades for Jelly Bean.

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• Primefaces p:fileupload component problem

  - by Nitesh Panchal

  Hello, I am using Primefaces 2.0.1 but the FileUpload component is not working properly. It uses JQuery uploadify behind the scenes. This is my web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <filter> <filter-name>PrimeFaces FileUpload Filter</filter-name> <filter-class>org.primefaces.webapp.filter.FileUploadFilter</filter-class> </filter> <filter-mapping> <filter-name>PrimeFaces FileUpload Filter</filter-name> <servlet-name>Faces Servlet</servlet-name> </filter-mapping> <servlet> <servlet-name>Faces Servlet</servlet-name> <servlet-class>javax.faces.webapp.FacesServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Faces Servlet</servlet-name> <url-pattern>*.jsf</url-pattern> </servlet-mapping> <servlet> <servlet-name>Resource Servlet</servlet-name> <servlet-class>org.primefaces.resource.ResourceServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>Resource Servlet</servlet-name> <url-pattern>/primefaces_resource/*</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsf</welcome-file> </welcome-file-list> </web-app> This is my index.xhtml :- <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:p="http://primefaces.prime.com.tr/ui"> <h:head> <title>Facelet Title</title> </h:head> <h:body> <h:form prependId="false"> <h:commandButton actionListener="#{NewJSFManagedBean.add}" value="add"/> <p:fileUpload auto="false" widgetVar="fileUpl" fileUploadListener="#{NewJSFManagedBean.saveFile}"/> </h:form> </h:body> </html> I have following libraries in my classpath :- primefaces 2.0.1 commons-beanutils commons-beanutils-bean-collection commons-digestor commons-fileUpload commons-io commons-logging jhighlight The file gets correctly uploaded in /tmp but in browser it always says HTTP error. Please help me. It used to work till yesterday. But today i did a fresh installation of Glassfish and it has stopped working.

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• Is C# slower than VB.NET?

  - by Matt Winckler

  Believe it or not, despite the title, this is not a troll. Running some benchmarks this morning, my colleagues and I have discovered some strange things concerning performance, and I am wondering if we're doing something horribly wrong. We started out comparing C# vs. Delphi Prism calculating prime numbers, and found that Prism was about 30% faster. I figured maybe CodeGear did more optimization when generating IL (the exe was about twice as big as C#'s and had all sorts of different IL in it.) So I decided to write a test in VB.NET as well, assuming that Microsoft's compilers would end up writing essentially the same IL for each language. However, the result there was more shocking: C# was more than three times slower than VB running the same operations. The generated IL was different, but not extremely so, and I'm not good enough at reading it to understand the differences. As a fan of C#, this apparent slowness wounds me horribly, and I am left wondering: what in the world is going on here? Is it time to pack it all in and go write web apps in Ruby? ;-) I've included the code for each below--just copy it into a new VB or C# console app, and run. On my machine, VB finds 348513 primes in about 6.36 seconds. C# finds the same number of primes in 21.76 seconds. (I've got an Intel Core2 Quad Q6600 @2.4Ghz; on another Intel machine in the office the code for both runs much faster but the ratio is about the same; on an AMD machine here the timing is ~10 seconds for VB and ~13 for C#--much less difference, but C# is still always slower.) Both of the console applications were compiled in Release mode, but otherwise no project settings were changed from the defaults generated by Visual Studio 2008. Is it a generally-known fact that C#'s generated IL is worse than VB's? Or is this a strange edge case? Or is my code flawed somehow (most likely)? Any insights are appreciated. VB code Imports System.Diagnostics Module Module1 Private temp As List(Of Int32) Private sw As Stopwatch Private totalSeconds As Double Sub Main() serialCalc() End Sub Private Sub serialCalc() temp = New List(Of Int32)() sw = Stopwatch.StartNew() For i As Int32 = 2 To 5000000 testIfPrimeSerial(i) Next sw.Stop() totalSeconds = sw.Elapsed.TotalSeconds Console.WriteLine(String.Format("{0} seconds elapsed.", totalSeconds)) Console.WriteLine(String.Format("{0} primes found.", temp.Count)) Console.ReadKey() End Sub Private Sub testIfPrimeSerial(ByVal suspectPrime As Int32) For i As Int32 = 2 To Math.Sqrt(suspectPrime) If (suspectPrime Mod i = 0) Then Exit Sub End If Next temp.Add(suspectPrime) End Sub End Module C# Code using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Diagnostics; namespace FindPrimesCSharp { class Program { List<Int32> temp = new List<Int32>(); Stopwatch sw; double totalSeconds; static void Main(string[] args) { new Program().serialCalc(); } private void serialCalc() { temp = new List<Int32>(); sw = Stopwatch.StartNew(); for (Int32 i = 2; i <= 5000000; i++) { testIfPrimeSerial(i); } sw.Stop(); totalSeconds = sw.Elapsed.TotalSeconds; Console.WriteLine(string.Format("{0} seconds elapsed.", totalSeconds)); Console.WriteLine(string.Format("{0} primes found.", temp.Count)); Console.ReadKey(); } private void testIfPrimeSerial(Int32 suspectPrime) { for (Int32 i = 2; i <= Math.Sqrt(suspectPrime); i++) { if (suspectPrime % i == 0) return; } temp.Add(suspectPrime); } } }

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• Optimizing Python code with many attribute and dictionary lookups

  - by gotgenes

  I have written a program in Python which spends a large amount of time looking up attributes of objects and values from dictionary keys. I would like to know if there's any way I can optimize these lookup times, potentially with a C extension, to reduce the time of execution, or if I need to simply re-implement the program in a compiled language. The program implements some algorithms using a graph. It runs prohibitively slowly on our data sets, so I profiled the code with cProfile using a reduced data set that could actually complete. The vast majority of the time is being burned in one function, and specifically in two statements, generator expressions, within the function: The generator expression at line 202 is neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) and the generator expression at line 204 is neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) The source code for this function of context provided below. selected_nodes is a set of nodes in the interaction_graph, which is a NetworkX Graph instance. node_neighbors is an iterator from Graph.neighbors_iter(). Graph itself uses dictionaries for storing nodes and edges. Its Graph.node attribute is a dictionary which stores nodes and their attributes (e.g., 'weight') in dictionaries belonging to each node. Each of these lookups should be amortized constant time (i.e., O(1)), however, I am still paying a large penalty for the lookups. Is there some way which I can speed up these lookups (e.g., by writing parts of this as a C extension), or do I need to move the program to a compiled language? Below is the full source code for the function that provides the context; the vast majority of execution time is spent within this function. def calculate_node_z_prime( node, interaction_graph, selected_nodes ): """Calculates a z'-score for a given node. The z'-score is based on the z-scores (weights) of the neighbors of the given node, and proportional to the z-score (weight) of the given node. Specifically, we find the maximum z-score of all neighbors of the given node that are also members of the given set of selected nodes, multiply this z-score by the z-score of the given node, and return this value as the z'-score for the given node. If the given node has no neighbors in the interaction graph, the z'-score is defined as zero. Returns the z'-score as zero or a positive floating point value. :Parameters: - `node`: the node for which to compute the z-prime score - `interaction_graph`: graph containing the gene-gene or gene product-gene product interactions - `selected_nodes`: a `set` of nodes fitting some criterion of interest (e.g., annotated with a term of interest) """ node_neighbors = interaction_graph.neighbors_iter(node) neighbors_in_selected_nodes = (neighbor for neighbor in node_neighbors if neighbor in selected_nodes) neighbor_z_scores = (interaction_graph.node[neighbor]['weight'] for neighbor in neighbors_in_selected_nodes) try: max_z_score = max(neighbor_z_scores) # max() throws a ValueError if its argument has no elements; in this # case, we need to set the max_z_score to zero except ValueError, e: # Check to make certain max() raised this error if 'max()' in e.args[0]: max_z_score = 0 else: raise e z_prime = interaction_graph.node[node]['weight'] * max_z_score return z_prime Here are the top couple of calls according to cProfiler, sorted by time. ncalls tottime percall cumtime percall filename:lineno(function) 156067701 352.313 0.000 642.072 0.000 bpln_contextual.py:204(<genexpr>) 156067701 289.759 0.000 289.759 0.000 bpln_contextual.py:202(<genexpr>) 13963893 174.047 0.000 816.119 0.000 {max} 13963885 69.804 0.000 936.754 0.000 bpln_contextual.py:171(calculate_node_z_prime) 7116883 61.982 0.000 61.982 0.000 {method 'update' of 'set' objects}

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• Reuse a facelet in multiple beans

  - by Seitaridis

  How do I invoke/access a property of a managed bean when the bean name is known, but is not yet constructed? For example: <p:selectOneMenu value="#{eval.evaluateAsBean(bean).text}" > <f:selectItems value="#{eval.evaluateAsBean(bean).values}" var="val" itemLabel="#{val}" itemValue="#{val}" /> </p:selectOneMenu> If there is a managed bean called testBean and in my view bean has the "testBean"value, I want the text or values property of testBean to be called. EDIT1 The context An object consists of a list of properties(values). One property is modified with a custom JSF editor, depending on its type. The list of editors is determined from the object's type, and displayed in a form using custom:include tags. This custom tag is used to dynamically include the editors <custom:include src="#{editor.component}">. The component property points to the location of the JSF editor. In my example some editors(rendered as select boxes) will use the same facelet(dynamicDropdown.xhtml). Every editor has a session scoped managed bean. I want to reuse the same facelet with multiple beans and to pass the name of the bean to dynamicDropdown.xhtml using the bean param. genericAccount.xhtml <p:dataTable value="#{group.editors}" var="editor"> <p:column headerText="Key"> <h:outputText value="#{editor.name}" /> </p:column> <p:column headerText="Value"> <h:panelGroup rendered="#{not editor.href}"> <h:outputText value="#{editor.component}" escape="false" /> </h:panelGroup> <h:panelGroup rendered="#{editor.href}"> <custom:include src="#{editor.component}"> <ui:param name="enabled" value="#{editor.enabled}"/> <ui:param name="bean" value="#{editor.bean}"/> <custom:include> </h:panelGroup> </p:column> </p:dataTable> #{editor.component} refers to a dynamicDropdown.xhtml file. dynamicDropdown.xhtml <ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.prime.com.tr/ui"> <p:selectOneMenu value="#{eval.evaluateAsBean(bean).text}" > <f:selectItems value="#{eval.evaluateAsBean(bean).values}" var="val" itemLabel="#{val}" itemValue="#{val}" /> </p:selectOneMenu> </ui:composition> eval is a managed bean: @ManagedBean(name = "eval") @ApplicationScoped public class ELEvaluator { ... public Object evaluateAsBean(String el) { FacesContext context = FacesContext.getCurrentInstance(); Object bean = context.getELContext() .getELResolver().getValue(context.getELContext(), null, el); return bean; } ... }

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• Why does @PostConstruct callback fire every time even though bean is @ViewScoped? JSF

  - by Nitesh Panchal

  Hello, I am using datatable on page and using binding attribute to bind it to my backing bean. This is my code :- <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:h="http://java.sun.com/jsf/html" xmlns:p="http://primefaces.prime.com.tr/ui"> <h:head> <title>Facelet Title</title> </h:head> <h:body> <h:form prependId="false"> <h:dataTable var="item" value="#{testBean.stringCollection}" binding="#{testBean.dataTable}"> <h:column> <h:outputText value="#{item}"/> </h:column> <h:column> <h:commandButton value="Click" actionListener="#{testBean.action}"/> </h:column> </h:dataTable> </h:form> </h:body> </html> This is my bean :- package managedBeans; import java.io.Serializable; import java.util.ArrayList; import java.util.List; import javax.annotation.PostConstruct; import javax.faces.bean.ManagedBean; import javax.faces.bean.ViewScoped; import javax.faces.component.html.HtmlDataTable; @ManagedBean(name="testBean") @ViewScoped public class testBean implements Serializable { private List<String> stringCollection; public List<String> getStringCollection() { return stringCollection; } public void setStringCollection(List<String> stringCollection) { this.stringCollection = stringCollection; } private HtmlDataTable dataTable; public HtmlDataTable getDataTable() { return dataTable; } public void setDataTable(HtmlDataTable dataTable) { this.dataTable = dataTable; } @PostConstruct public void init(){ System.out.println("Post Construct fired!!"); stringCollection = new ArrayList<String>(); stringCollection.add("a"); stringCollection.add("b"); stringCollection.add("c"); } public void action(){ System.out.println("Clicked!!"); } } Please tell me why is the @PostConstruct firing each and every time i click on button? It should fire only once as long as i am on same page beacause my bean is @ViewScoped. Further, if i remove the binding attribute then everything works fine and @PostConstruct callback fires only once. Then why every time when i use binding attribute? I need binding attribute and want to perform initialisation tasks like fetching data from webservice, etc only once. What should i do? Where should i write my initialisation task?

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• Slow Javascript touch events on Android

  - by oneself

  I'm trying to write a simple html based drawing application (standalone simplified code attached bellow). I've tested this on the following devices: iPad 1 and 2: Works great ASUS T101 running Windows: Works great Samsung Galaxy Tab: Extremely slow and patchy -- unusable. Lenovo IdeaPad K1: Extremely slow and patchy -- unusable. Asus Transformer Prime: Noticeable lag compare with the iPad -- close to usable. The Asus tablet is running ICS, the other android tablets are running 3.1 and 3.2. I tested using the stock Android browser. I also tried the Android Chrome Beta, but that was even worse. My questions is why are the Android tablets so slow? Am I doing something wrong or is it an inherit problem with Android OS or browser, or is there anything I can do about it in my code? multi.html: <html> <body> <style media="screen"> canvas { border: 1px solid #CCC; } </style> <canvas style="" id="draw" height="450" width="922"></canvas> <script class="jsbin" src="jquery.js"></script> <script src="multi.js"></script> </body> </html> multi.js: var CanvasDrawr = function(options) { // grab canvas element var canvas = document.getElementById(options.id), ctxt = canvas.getContext("2d"); canvas.style.width = '100%' canvas.width = canvas.offsetWidth; canvas.style.width = ''; // set props from options, but the defaults are for the cool kids ctxt.lineWidth = options.size || Math.ceil(Math.random() * 35); ctxt.lineCap = options.lineCap || "round"; ctxt.pX = undefined; ctxt.pY = undefined; var lines = [,,]; var offset = $(canvas).offset(); var eventCount = 0; var self = { // Bind click events init: function() { // Set pX and pY from first click canvas.addEventListener('touchstart', self.preDraw, false); canvas.addEventListener('touchmove', self.draw, false); }, preDraw: function(event) { $.each(event.touches, function(i, touch) { var id = touch.identifier; lines[id] = { x : this.pageX - offset.left, y : this.pageY - offset.top, color : 'black' }; }); event.preventDefault(); }, draw: function(event) { var e = event, hmm = {}; eventCount += 1; $.each(event.touches, function(i, touch) { var id = touch.identifier, moveX = this.pageX - offset.left - lines[id].x, moveY = this.pageY - offset.top - lines[id].y; var ret = self.move(id, moveX, moveY); lines[id].x = ret.x; lines[id].y = ret.y; }); event.preventDefault(); }, move: function(i, changeX, changeY) { ctxt.strokeStyle = lines[i].color; ctxt.beginPath(); ctxt.moveTo(lines[i].x, lines[i].y); ctxt.lineTo(lines[i].x + changeX, lines[i].y + changeY); ctxt.stroke(); ctxt.closePath(); return { x: lines[i].x + changeX, y: lines[i].y + changeY }; }, }; return self.init(); }; $(function(){ var drawr = new CanvasDrawr({ id: "draw", size: 5 }); });

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• Parallelism in .NET – Part 2, Simple Imperative Data Parallelism

  - by Reed

  In my discussion of Decomposition of the problem space, I mentioned that Data Decomposition is often the simplest abstraction to use when trying to parallelize a routine.  If a problem can be decomposed based off the data, we will often want to use what MSDN refers to as Data Parallelism as our strategy for implementing our routine.  The Task Parallel Library in .NET 4 makes implementing Data Parallelism, for most cases, very simple. Data Parallelism is the main technique we use to parallelize a routine which can be decomposed based off data.  Data Parallelism refers to taking a single collection of data, and having a single operation be performed concurrently on elements in the collection.  One side note here: Data Parallelism is also sometimes referred to as the Loop Parallelism Pattern or Loop-level Parallelism.  In general, for this series, I will try to use the terminology used in the MSDN Documentation for the Task Parallel Library.  This should make it easier to investigate these topics in more detail. Once we’ve determined we have a problem that, potentially, can be decomposed based on data, implementation using Data Parallelism in the TPL is quite simple.  Let’s take our example from the Data Decomposition discussion – a simple contrast stretching filter.  Here, we have a collection of data (pixels), and we need to run a simple operation on each element of the pixel.  Once we know the minimum and maximum values, we most likely would have some simple code like the following: for (int row=0; row < pixelData.GetUpperBound(0); ++row) { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } } .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; } This simple routine loops through a two dimensional array of pixelData, and calls the AdjustContrast routine on each pixel. As I mentioned, when you’re decomposing a problem space, most iteration statements are potentially candidates for data decomposition.  Here, we’re using two for loops – one looping through rows in the image, and a second nested loop iterating through the columns.  We then perform one, independent operation on each element based on those loop positions. This is a prime candidate – we have no shared data, no dependencies on anything but the pixel which we want to change.  Since we’re using a for loop, we can easily parallelize this using the Parallel.For method in the TPL: Parallel.For(0, pixelData.GetUpperBound(0), row => { for (int col=0; col < pixelData.GetUpperBound(1); ++col) { pixelData[row, col] = AdjustContrast(pixelData[row, col], minPixel, maxPixel); } }); Here, by simply changing our first for loop to a call to Parallel.For, we can parallelize this portion of our routine.  Parallel.For works, as do many methods in the TPL, by creating a delegate and using it as an argument to a method.  In this case, our for loop iteration block becomes a delegate creating via a lambda expression.  This lets you write code that, superficially, looks similar to the familiar for loop, but functions quite differently at runtime. We could easily do this to our second for loop as well, but that may not be a good idea.  There is a balance to be struck when writing parallel code.  We want to have enough work items to keep all of our processors busy, but the more we partition our data, the more overhead we introduce.  In this case, we have an image of data – most likely hundreds of pixels in both dimensions.  By just parallelizing our first loop, each row of pixels can be run as a single task.  With hundreds of rows of data, we are providing fine enough granularity to keep all of our processors busy. If we parallelize both loops, we’re potentially creating millions of independent tasks.  This introduces extra overhead with no extra gain, and will actually reduce our overall performance.  This leads to my first guideline when writing parallel code: Partition your problem into enough tasks to keep each processor busy throughout the operation, but not more than necessary to keep each processor busy. Also note that I parallelized the outer loop.  I could have just as easily partitioned the inner loop.  However, partitioning the inner loop would have led to many more discrete work items, each with a smaller amount of work (operate on one pixel instead of one row of pixels).  My second guideline when writing parallel code reflects this: Partition your problem in a way to place the most work possible into each task. This typically means, in practice, that you will want to parallelize the routine at the “highest” point possible in the routine, typically the outermost loop.  If you’re looking at parallelizing methods which call other methods, you’ll want to try to partition your work high up in the stack – as you get into lower level methods, the performance impact of parallelizing your routines may not overcome the overhead introduced. Parallel.For works great for situations where we know the number of elements we’re going to process in advance.  If we’re iterating through an IList<T> or an array, this is a typical approach.  However, there are other iteration statements common in C#.  In many situations, we’ll use foreach instead of a for loop.  This can be more understandable and easier to read, but also has the advantage of working with collections which only implement IEnumerable<T>, where we do not know the number of elements involved in advance. As an example, lets take the following situation.  Say we have a collection of Customers, and we want to iterate through each customer, check some information about the customer, and if a certain case is met, send an email to the customer and update our instance to reflect this change.  Normally, this might look something like: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } } Here, we’re doing a fair amount of work for each customer in our collection, but we don’t know how many customers exist.  If we assume that theStore.GetLastContact(customer) and theStore.EmailCustomer(customer) are both side-effect free, thread safe operations, we could parallelize this using Parallel.ForEach: Parallel.ForEach(customers, customer => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { theStore.EmailCustomer(customer); customer.LastEmailContact = DateTime.Now; } }); Just like Parallel.For, we rework our loop into a method call accepting a delegate created via a lambda expression.  This keeps our new code very similar to our original iteration statement, however, this will now execute in parallel.  The same guidelines apply with Parallel.ForEach as with Parallel.For. The other iteration statements, do and while, do not have direct equivalents in the Task Parallel Library.  These, however, are very easy to implement using Parallel.ForEach and the yield keyword. Most applications can benefit from implementing some form of Data Parallelism.  Iterating through collections and performing “work” is a very common pattern in nearly every application.  When the problem can be decomposed by data, we often can parallelize the workload by merely changing foreach statements to Parallel.ForEach method calls, and for loops to Parallel.For method calls.  Any time your program operates on a collection, and does a set of work on each item in the collection where that work is not dependent on other information, you very likely have an opportunity to parallelize your routine.

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