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• 80 Percent of North American Developers Think 30 / 70 Revenue Split at App Stores is Unfair

  Only 15 percent of application development pros say app stores are their preferred distribution model.

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• Is ORM an Anti-Pattern?

  - by derphil

  I had a very stimulating and interessting discussion with a colleague about ORM and it's Pros and Cons. In my opinion, an ORM is useful only in the rarest cases. At least in my experience. But I don't want to list my own arguments at this time. So I ask you, what do you think about ORM? What are the Pros and the Cons? P.S. I've posted this "question" yesterday on Stackoverflow, but some of the user think, that this should better posted here.

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• Can mass different log-in pages result in SEO duplicate and/or low quality punishments?

  - by Noam

  I have internal pages that rely on an external API which I would like to build upon user request. Two options I thought about: Make lots of 'thin' pages that specifies that if you want content about X, you need to log-in, and then the page will be built. Pros: user understands what he'll get when logging in. Cons: SEO implications of such a solution due to the mass 'low quality' and 'cross-sites duplicate content' Make them all redirect to ONE same generic log-in page. Pros: No duplicate low quality content. Cons: Lots of internal links to the same log-in page. Which would you recommend?

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• Building a Website For Your Online Business & Need a Template?

  Building a website and need direction? Learn how the pros do it!

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• when should be choose simple php mail and when smpt with loggin+password?

  - by user43353

  Hi, My Case: web application that need to send 1,000 messages per day to main gmail account. (Only need to send email, not need receive emails - email client) 1. option - use php mail function + sendmail + config php.ini php example: <?php $to = '[email protected]'; $subject = 'the subject'; $message = 'hello'; $headers = 'From: [email protected]' . "\r\n" . 'Reply-To: [email protected]' . "\r\n" . 'X-Mailer: PHP/' . phpversion(); mail($to, $subject, $message, $headers); ?> php.ini config (ubuntu): sendmail_path = /usr/sbin/sendmail -t -i pros:don't need email account, easy to setup cons:? 2. option - use Zend_Mail + transport on smpt+ password auto php example(need include Zend_Mail classes): $config = array('auth' => 'login', 'username' => 'myusername', 'password' => 'password'); $transport = new Zend_Mail_Transport_Smtp('mail.server.com', $config); $mail = new Zend_Mail(); $mail->setBodyText('This is the text of the mail.'); $mail->setFrom('[email protected]', 'Some Sender'); $mail->addTo('[email protected]', 'Some Recipient'); $mail->setSubject('TestSubject'); $mail->send($transport); pros:? cons:? Questions: Can 1 option be filtered by gmail email server as spam? please can you add pros + cons to options above Thanks

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• LYNC 2010 Dial-In in Meeting DTMF issue

  - by user140116

  We are facing an issue in the LYNC2010 dial-in to a meeting. We redirect an Asterisk number to LYNC, whitch connects successfully in the dial-in plan of LYNC. After calling from external network to the given number, we hear LYNC aswering and prompting us to enter the PIN and afterwards the hash key. I should mention that all other dials to LYNC from Asterisk and vise versa are routed successfully. Also all DTMF we send to Asterisk from the phone (IVR, Extension, PIN etc) are routed also fine Afterwards we press the appropriate pin folowed by the hash keyand we get 'Sorry I can't find meeting with that number' Some pros mentioned that it might be dtmfmode=RFC2833 or dtmfmode=auto in Asterisk (All checked and tried). Some pros mentioned, that there is a problem in geeral in LYNC and DTMF (even with Cisco Call Manager). Some other pros mentioned that chack box 'Enable refer support' in Voice Routinh\Trunk Configuration' in LYNC has to be unchecked (Also tested). The problem stil remains and there is no way to enter a meeting room by dial-in. ANY idea would be appreciated!!!!!!!!

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• Upload large files via a webpage

  - by Hultner

  What way is the best way to let users upload large files from there webbrowser to a server. I'm talking 200MB+ possible up to a few gigatyes. I have been thinking of a few possible solutions to the problem (not tried them yet) and this is basically the things I came up with. Server download speed will not be a problem but the users connection possibly could. Having some sort of applet on the client side written in Java or Flash which sends the file in parts (is this possible with an applet) to a php/other script on the server and a checksum+ some other info about the file. On the server scripts all the parts and the info file is saved in a temporary directory wich has a unique name based on the checksum of the file and the ip of the user. When the last chunk is sent the applet sends a signal to the server saying it's finished and the server put the file together in the right location. If a chunk doesn't match the checksum for that part the server will send a response to the applet telling it to reupload that chunk. I don't know how important the checksum checking is since it's all tcpackages, someone with more insigth migth be able to answer on that. This is probably the worst way, changing the settings on your server to allow huge fileuploads via an inputfiel. Do it like a normal transfer. User an uploadmanager which does pretty much the same thing as applet i mentioned above. Pros of the first is probably that it would most likely be rather secure, you could show progress as well and possibly resume an upload if ip hasn't changed and do a threaded upload of the chunks. Cons of the first is that the user will need flash/java for it to work. Pros of the 2nd is that it will pretty much work for everyone but cons are big, first there's no way resuming an intruppted download and if something is wrong the whole file would have to be reuploaded is a few of cons. For the third one the pros is pretty muc the same as for the first but the cons is that the user would have to download an application to their computer and run and the application will have to be have to be compatible with their computer and OS. Another way may be a combination of two. Lets say an applet for bigger or more files and a simple input which is rather restricted to maybe max 10-20MB for smaller files and comability. There are probably other much smarter ways to tackle this and that's why I'm asking for advice here on SO.

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• How to generate DELETE statements in PL/SQL, based on the tables FK relations?

  - by The chicken in the kitchen

  Is it possible via script/tool to generate authomatically many delete statements based on the tables fk relations, using Oracle PL/SQL? In example: I have the table: CHICKEN (CHICKEN_CODE NUMBER) and there are 30 tables with fk references to its CHICKEN_CODE that I need to delete; there are also other 150 tables foreign-key-linked to that 30 tables that I need to delete first. Is there some tool/script PL/SQL that I can run in order to generate all the necessary delete statements based on the FK relations for me? (by the way, I know about cascade delete on the relations, but please pay attention: I CAN'T USE IT IN MY PRODUCTION DATABASE, because it's dangerous!) I'm using Oracle DataBase 10G R2. This is the result I've written, but it is not recursive: This is a view I have previously written, but of course it is not recursive! CREATE OR REPLACE FORCE VIEW RUN ( OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, VINCOLO ) AS SELECT OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, '(' || LTRIM ( EXTRACT (XMLAGG (XMLELEMENT ("x", ',' || COLUMN_NAME)), '/x/text()'), ',') || ')' VINCOLO FROM ( SELECT CON1.OWNER OWNER_1, CON1.TABLE_NAME TABLE_NAME_1, CON1.CONSTRAINT_NAME CONSTRAINT_NAME_1, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME FROM DBA_CONSTRAINTS CON, DBA_CONS_COLUMNS COL, DBA_CONSTRAINTS CON1 WHERE CON.OWNER = 'TABLE_OWNER' AND CON.TABLE_NAME = 'TABLE_OWNED' AND ( (CON.CONSTRAINT_TYPE = 'P') OR (CON.CONSTRAINT_TYPE = 'U')) AND COL.TABLE_NAME = CON1.TABLE_NAME AND COL.CONSTRAINT_NAME = CON1.CONSTRAINT_NAME --AND CON1.OWNER = CON.OWNER AND CON1.R_CONSTRAINT_NAME = CON.CONSTRAINT_NAME AND CON1.CONSTRAINT_TYPE = 'R' GROUP BY CON1.OWNER, CON1.TABLE_NAME, CON1.CONSTRAINT_NAME, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME) GROUP BY OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME; ... and it contains the error of using DBA_CONSTRAINTS instead of ALL_CONSTRAINTS... Please pay attention to this: http://stackoverflow.com/questions/485581/generate-delete-statement-from-foreign-key-relationships-in-sql-2008/2677145#2677145 Another user has just written it in SQL SERVER 2008, anyone is able to convert to Oracle 10G PL/SQL? I am not able to... :-( This is the code written by another user in SQL SERVER 2008: DECLARE @COLUMN_NAME AS sysname DECLARE @TABLE_NAME AS sysname DECLARE @IDValue AS int SET @COLUMN_NAME = '<Your COLUMN_NAME here>' SET @TABLE_NAME = '<Your TABLE_NAME here>' SET @IDValue = 123456789 DECLARE @sql AS varchar(max) ; WITH RELATED_COLUMNS AS ( SELECT QUOTENAME(c.TABLE_SCHEMA) + '.' + QUOTENAME(c.TABLE_NAME) AS [OBJECT_NAME] ,c.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.COLUMNS AS c WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLES AS t WITH (NOLOCK) ON c.TABLE_CATALOG = t.TABLE_CATALOG AND c.TABLE_SCHEMA = t.TABLE_SCHEMA AND c.TABLE_NAME = t.TABLE_NAME AND t.TABLE_TYPE = 'BASE TABLE' INNER JOIN ( SELECT rc.CONSTRAINT_CATALOG ,rc.CONSTRAINT_SCHEMA ,lkc.TABLE_NAME ,lkc.COLUMN_NAME FROM PBANKDW.INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc WITH (NOLOCK) INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE lkc WITH (NOLOCK) ON lkc.CONSTRAINT_CATALOG = rc.CONSTRAINT_CATALOG AND lkc.CONSTRAINT_SCHEMA = rc.CONSTRAINT_SCHEMA AND lkc.CONSTRAINT_NAME = rc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc WITH (NOLOCK) ON rc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rc.UNIQUE_CONSTRAINT_NAME = tc.CONSTRAINT_NAME INNER JOIN PBANKDW.INFORMATION_SCHEMA.KEY_COLUMN_USAGE rkc WITH (NOLOCK) ON rkc.CONSTRAINT_CATALOG = tc.CONSTRAINT_CATALOG AND rkc.CONSTRAINT_SCHEMA = tc.CONSTRAINT_SCHEMA AND rkc.CONSTRAINT_NAME = tc.CONSTRAINT_NAME WHERE rkc.COLUMN_NAME = @COLUMN_NAME AND rkc.TABLE_NAME = @TABLE_NAME ) AS j ON j.CONSTRAINT_CATALOG = c.TABLE_CATALOG AND j.CONSTRAINT_SCHEMA = c.TABLE_SCHEMA AND j.TABLE_NAME = c.TABLE_NAME AND j.COLUMN_NAME = c.COLUMN_NAME ) SELECT @sql = COALESCE(@sql, '') + 'DELETE FROM ' + [OBJECT_NAME] + ' WHERE ' + [COLUMN_NAME] + ' = ' + CONVERT(varchar, @IDValue) + CHAR(13) + CHAR(10) FROM RELATED_COLUMNS PRINT @sql Thank to Charles, this is the latest not working release of the software, I have added a parameter with the OWNER because the referential integrities propagate through about 5 other Oracle users (!!!): CREATE OR REPLACE PROCEDURE delete_cascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete_cascade (tab_name, tab_name_owner); delete_command := ''; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');'; INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; END; / In the cursor CONS_CURSOR I have added the condition: AND delete_rule = 'NO ACTION'; in order to avoid deletion in case of referential integrities with DELETE_RULE = 'CASCADE' or DELETE_RULE = 'SET NULL'. Now I have tried to turn from stored procedure to stored function, but the delete statements are not correct: CREATE OR REPLACE FUNCTION deletecascade ( parent_table VARCHAR2, parent_table_owner VARCHAR2) RETURN VARCHAR2 IS cons_name VARCHAR2 (30); tab_name VARCHAR2 (30); tab_name_owner VARCHAR2 (30); parent_cons VARCHAR2 (30); parent_col VARCHAR2 (30); delete1 VARCHAR (500); delete2 VARCHAR (500); delete_command VARCHAR (4000); AT_LEAST_ONE_ITERATION NUMBER DEFAULT 0; CURSOR cons_cursor IS SELECT constraint_name, r_constraint_name, table_name, constraint_type FROM all_constraints WHERE constraint_type = 'R' AND r_constraint_name IN (SELECT constraint_name FROM all_constraints WHERE constraint_type IN ('P', 'U') AND table_name = parent_table AND owner = parent_table_owner) AND delete_rule = 'NO ACTION'; CURSOR tabs_cursor IS SELECT DISTINCT table_name FROM all_cons_columns WHERE constraint_name = cons_name; CURSOR child_cols_cursor IS SELECT column_name, position FROM all_cons_columns WHERE constraint_name = cons_name AND table_name = tab_name; BEGIN FOR cons IN cons_cursor LOOP AT_LEAST_ONE_ITERATION := 1; cons_name := cons.constraint_name; parent_cons := cons.r_constraint_name; SELECT DISTINCT table_name, owner INTO tab_name, tab_name_owner FROM all_cons_columns WHERE constraint_name = cons_name; delete1 := ''; delete2 := ''; FOR col IN child_cols_cursor LOOP SELECT DISTINCT column_name INTO parent_col FROM all_cons_columns WHERE constraint_name = parent_cons AND position = col.position; IF delete1 IS NULL THEN delete1 := col.column_name; ELSE delete1 := delete1 || ', ' || col.column_name; END IF; IF delete2 IS NULL THEN delete2 := parent_col; ELSE delete2 := delete2 || ', ' || parent_col; END IF; END LOOP; delete_command := 'delete from ' || tab_name_owner || '.' || tab_name || ' where (' || delete1 || ') in (select ' || delete2 || ' from ' || parent_table_owner || '.' || parent_table || ');' || deletecascade (tab_name, tab_name_owner); INSERT INTO ris VALUES (SEQUENCE_COMANDI.NEXTVAL, delete_command); COMMIT; END LOOP; IF AT_LEAST_ONE_ITERATION = 1 THEN RETURN ' where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION;'; ELSE RETURN NULL; END IF; END; / Please assume that V_CHICKEN and V_NATION are the criteria to select the CHICKEN to delete from the root table: the condition is: "where COD_CHICKEN = V_CHICKEN AND COD_NATION = V_NATION" on the root table.

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• When should I use MySQL compressed protocol?

  - by ento

  I've learned that MySQL can compress communication between servers and clients. Compression is used if both client and server support zlib compression, and the client requests compression. (from MySQL Forge Wiki) The most obvious pros and cons are pros: Reduced payload size cons: Increased computation time So, is compressed protocol something I should enable whenever I can afford servers with adequate specs? Are there other factors I should consider?

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• dirname(__FILE__) VS setting global variable to directories

  - by SAFAD

  what are the pros and cons of using this : $globals['server_url'] = dirname(__FILE__); $globals['mainfiles'] = dirname(__FILE__).'/main'; and the pros and cons of using this : $globals['server_url'] = '/srv/www/htdocs/somwhere/'; $globals['mainfiles'] = '/srv/www/htdocs/somwhere/main'; And what do you suggest. by the way: these are set in config.php file which is called by other files as well, to stop directory conflicts when including files we use it like this : require_once($globals['server_url'].'/test.php');

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• SQL Server 2008 : Standard or SQL Express

  - by dr

  Which is a better choice on a development box if you primarily develop Asp.Net applications and SSRS reports. I have never had to use the Express editions, so I don't really know the pros or cons. The cons I have listed for Standard+ editions are: toll it takes on system resources pain to attach database for projects pain to detach unused databases $$$ Pros: You have everything you need Management Studio features Easy move to production

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• Why or why not use a DataSource to fill ASP controls?

  - by Brad8118

  So we have a GridView asp control and one of my coworkers doesn't like to use an DataSource to fill the GridView. I wasn't sure if/what the pros and cons are of using one. I don't mind using going through the wizard to set the type, and the select/update methods. Besides using the wizard are there pros and cons?

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• Contracting as a Software Developer in the UK

  - by Frez

  Normal 0 false false false EN-GB X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} Having had some 15 years’ experience of working as a software contractor, I am often asked by developers who work as permanent employees (permies) about the pros and cons of working as a software consultant through my own limited company and whether the move would be a good one for them. Whilst it is possible to contract using other financial vehicles such as umbrella companies, this article will only consider limited companies as that is what I have experience of using. Contracting or consultancy requires a different mind-set from being a permanent member of staff, and not all developers are capable of this shift in attitude. Whilst you can look forward to an increase in the money you take home, there are real risks and expenses you would not normally be exposed to as a permie. So let us have a look at the pros and cons: Pros: More money There is no doubt that whilst you are working on contracts you will earn significantly more than you would as a permanent employee. Furthermore, working through a limited company is more tax efficient. Less politics You really have no need to involve yourself in office politics. When the end of the day comes you can go home and not think or worry about the power struggles within the company you are contracted to. Your career progression is not tied to the company. Expenses from gross income All your expenses of trading as a business will come out of your company’s gross income, i.e. before tax. This covers travelling expenses provided you have not been at the same client/location for more than two years, internet subscriptions, professional subscriptions, software, hardware, accountancy services and so on. Cons: Work is more transient Contracts typically range from a couple of weeks to a year, although will most likely start at 3 months. However, most contracts are extended either because the project you have been brought in to help with takes longer to deliver than expected, the client decides they can use you on other aspects of the project, or the client decides they would like to use you on other projects. The temporary nature of the work means that you will have down-time between contracts while you secure new opportunities during which time your company will have no income. You may need to attend several interviews before securing a new contract. Accountancy expenses Your company is a separate entity and there are accountancy requirements which, unless you like paperwork, means your company will need to appoint an accountant to prepare your company’s accounts. It may also be worth purchasing some accountancy software, so talk to your accountant about this as they may prefer you to use a particular software package so they can integrate it with their systems. VAT You will need to register your company for VAT. This is tax neutral for you as the VAT you charge your clients you will pass onto the government less any VAT you are reclaiming from expenses, but it is additional paperwork to undertake each quarter. It is worth checking out the Fixed Rate VAT Scheme that is available, particularly after the initial expenses of setting up your company are over. No training Clients take you on based on your skills, not to train you when they will lose that investment at the end of the contract, so understand that it is unlikely you will receive any training funded by a client. However, learning new skills during a contract is possible and you may choose to accept a contract on a lower rate if this is guaranteed as it will help secure future contracts. No financial extras You will have no free pension, life, accident, sickness or medical insurance unless you choose to purchase them yourself. A financial advisor can give you all the necessary advice in this area, and it is worth taking seriously. A year after I started as a consultant I contracted a serious illness, this kept me off work for over two months, my client was very understanding and it could have been much worse, so it is worth considering what your options might be in the case of illness, death and retirement. Agencies Whilst it is possible to work directly for end clients there are pros and cons of working through an agency.  The main advantage is cash flow, you invoice the agency and they typically pay you within a week, whereas working directly for a client could have you waiting up to three months to be paid. The downside of working for agencies, especially in the current difficult times, is that they may go out of business and you then have difficulty getting the money you are owed. Tax investigation It is possible that the Inland Revenue may decide to investigate your company for compliance with tax law. Insurance is available to cover you for this. My personal recommendation would be to join the PCG as this insurance is included as a benefit of membership, Professional Indemnity Some agencies require that you are covered by professional indemnity insurance; this is a cost you would not incur as a permie. Travel Unless you live in an area that has an abundance of opportunities, such as central London, it is likely that you will be travelling further, longer and with more expense than if you were permanently employed at a local company. This not only affects you monetarily, but also your quality of life and the ability to keep fit and healthy. Obtaining finance If you want to secure a mortgage on a property it can be more difficult or expensive, especially if you do not have three years of audited accounts to show a mortgage lender.   Caveat This post is my personal opinion and should not be used as a definitive guide or recommendation to contracting and whether it is suitable for you as an individual, i.e. I accept no responsibility if you decide to take up contracting based on this post and you fare badly for whatever reason.

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• What's up with LDoms: Part 5 - A few Words about Consoles

  - by Stefan Hinker

  Back again to look at a detail of LDom configuration that is often forgotten - the virtual console server. Remember, LDoms are SPARC systems.  As such, each guest will have it's own OBP running.  And to connect to that OBP, the administrator will need a console connection.  Since it's OBP, and not some x86 BIOS, this console will be very serial in nature ;-)  It's really very much like in the good old days, where we had a terminal concentrator where all those serial cables ended up in.  Just like with other components in LDoms, the virtualized solution looks very similar. Every LDom guest requires exactly one console connection.  Envision this similar to the RS-232 port on older SPARC systems.  The LDom framework provides one or more console services that provide access to these connections.  This would be the virtual equivalent of a network terminal server (NTS), where all those serial cables are plugged in.  In the physical world, we'd have a list somewhere, that would tell us which TCP-Port of the NTS was connected to which server.  "ldm list" does just that: root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 0.4% 27d 8h 22m jupiter bound ------ 5002 20 8G mars active -n---- 5000 2 8G 0.5% 55d 14h 10m venus active -n---- 5001 2 8G 0.5% 56d 40m pluto inactive ------ 4 4G The column marked "CONS" tells us, where to reach the console of each domain. In the case of the primary domain, this is actually a (more) physical connection - it's the console connection of the physical system, which is either reachable via the ILOM of that system, or directly via the serial console port on the chassis. All the other guests are reachable through the console service which we created during the inital setup of the system.  Note that pluto does not have a port assigned.  This is because pluto is not yet bound.  (Binding can be viewed very much as the assembly of computer parts - CPU, Memory, disks, network adapters and a serial console cable are all put together when binding the domain.)  Unless we set the port number explicitly, LDoms Manager will do this on a first come, first serve basis.  For just a few domains, this is fine.  For larger deployments, it might be a good idea to assign these port numbers manually using the "ldm set-vcons" command.  However, there is even better magic associated with virtual consoles. You can group several domains into one console group, reachable through one TCP port of the console service.  This can be useful when several groups of administrators are to be given access to different domains, or for other grouping reasons.  Here's an example: root@sun # ldm set-vcons group=planets service=console jupiter root@sun # ldm set-vcons group=planets service=console pluto root@sun # ldm bind jupiter root@sun # ldm bind pluto root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 6.1% 27d 8h 24m jupiter bound ------ 5002 200 8G mars active -n---- 5000 2 8G 0.6% 55d 14h 12m pluto bound ------ 5002 4 4G venus active -n---- 5001 2 8G 0.5% 56d 42m root@sun # telnet localhost 5002 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. sun-vnts-planets: h, l, c{id}, n{name}, q:l DOMAIN ID DOMAIN NAME DOMAIN STATE 2 jupiter online 3 pluto online sun-vnts-planets: h, l, c{id}, n{name}, q:npluto Connecting to console "pluto" in group "planets" .... Press ~? for control options .. What I did here was add the two domains pluto and jupiter to a new console group called "planets" on the service "console" running in the primary domain.  Simply using a group name will create such a group, if it doesn't already exist.  By default, each domain has its own group, using the domain name as the group name.  The group will be available on port 5002, chosen by LDoms Manager because I didn't specify it.  If I connect to that console group, I will now first be prompted to choose the domain I want to connect to from a little menu. Finally, here's an example how to assign port numbers explicitly: root@sun # ldm set-vcons port=5044 group=pluto service=console pluto root@sun # ldm bind pluto root@sun # ldm list NAME STATE FLAGS CONS VCPU MEMORY UTIL UPTIME primary active -n-cv- UART 16 7680M 3.8% 27d 8h 54m jupiter active -t---- 5002 200 8G 0.5% 30m mars active -n---- 5000 2 8G 0.6% 55d 14h 43m pluto bound ------ 5044 4 4G venus active -n---- 5001 2 8G 0.4% 56d 1h 13m With this, pluto would always be reachable on port 5044 in its own exclusive console group, no matter in which order other domains are bound. Now, you might be wondering why we always have to mention the console service name, "console" in all the examples here.  The simple answer is because there could be more than one such console service.  For all "normal" use, a single console service is absolutely sufficient.  But the system is flexible enough to allow more than that single one, should you need them.  In fact, you could even configure such a console service on a domain other than the primary (or control domain), which would make that domain a real console server.  I actually have a customer who does just that - they want to separate console access from the control domain functionality.  But this is definately a rather sophisticated setup. Something I don't want to go into in this post is access control.  vntsd, which is the daemon providing all these console services, is fully RBAC-aware, and you can configure authorizations for individual users to connect to console groups or individual domain's consoles.  If you can't wait until I get around to security, check out the man page of vntsd. Further reading: The Admin Guide is rather reserved on this subject.  I do recommend to check out the Reference Manual. The manpage for vntsd will discuss all the control sequences as well as the grouping and authorizations mentioned here.

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• SQLAuthority News – Book Signing Event – SQLPASS 2011 Event Log

  - by pinaldave

  I have been dreaming of writing book for really long time, and I finally got the chance – in fact, two chances!  I recently wrote two books: SQL Programming Joes 2 Pros: Programming and Development for Microsoft SQL Server 2008 [Amazon] | [Flipkart] | [Kindle] and SQL Wait Stats Joes 2 Pros: SQL Performance Tuning Techniques Using Wait Statistics, Types & Queues [Amazon] | [Flipkart] | [Kindle].  I had a lot of fun writing these two books, even though sometimes I had to sacrifice some family time and time for other personal development to write the books. The good side of writing book is that when the efforts put in writing books are recognize by books readers and kind organizations like expressor studio. Book Signing Event Book writing is a complex process.  Even after you spend months, maybe years, writing the material you still have to go through the editing and fact checking processes.  And, once the book is out there, there is no way to take back all the copies to change mistakes or add something you forgot.  Most of the time it is a one-way street. Book Signing Event Just like every author, I had a dream that after the books were written, they would be loved by people and gain acceptance by an audience. My first book, SQL Programming Joes 2 Pros: Programming and Development for Microsoft SQL Server 2008, is extremely popular because it helps lots of people learn various fundamental topics. My second book covers beginning to learn SQL Server Wait Stats, which is a relatively new subject. This book has had very good acceptance in the community. Book Signing Event Helping my community is my primary focus, so I was happy to see this year’s SQLPASS tag line: ‘This is a Community.‘ At the event, the expressor studio guys came up with a very novel idea. They had previously used my books and they had found them very useful. They got 100 copies of the book and decided to give it away to community folks. They invited me and my co-author Rick Morelan to hold a book signing event. We did a book signing on Thursday between 1 pm and 2 pm. Book Signing Event This event was one of the best events for me. This was my first book signing event outside of India. I reached the book signing location around 20 minutes before the scheduled time and what I saw was a big line for the book signing event. I felt very honored looking at the crowd and all the people around the event location. I felt very humbled when I saw some of my very close friends standing in the line to get my signature. It was really heartwarming to see so many enthusiasts waiting for more than an hour to get my signature. While standing in line I had the chance to have a conversation with every single person who showed up for the signature. I made sure that I repeated every single name and wrote it in every book with my signature. There is saying that if we write a name once we will remember it forever. I want to remember all of you who saw me at the book signing. Your comments were wonderful, your feedback was amazing and you were all very supportive. Book Signing Event I have made a note of every conversation I had with all of you when I was signing the books. Once again, I just want to express my thanks for coming to my book signing event. The whole experience was very humbling. On the top of it, I want to thank the expressor studio people who made it possible, who organized the whole signing event. I am so thankful to them for facilitating the whole experience, which is going to be hard to beat by any future experience. My books Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL PASS, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, SQLAuthority News, T SQL, Technology

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• Question on the implementation of my Entity System

  - by miguel.martin

  I am currently creating an Entity System, in C++, it is almost completed (I have all the code there, I just have to add a few things and test it). The only thing is, I can't figure out how to implement some features. This Entity System is based off a bit from the Artemis framework, however it is different. I'm not sure if I'll be able to type this out the way my head processing it. I'm going to basically ask whether I should do something over something else. Okay, now I'll give a little detail on my Entity System itself. Here are the basic classes that my Entity System uses to actually work: Entity - An Id (and some methods to add/remove/get/etc Components) Component - An empty abstract class ComponentManager - Manages ALL components for ALL entities within a Scene EntitySystem - Processes entities with specific components Aspect - The class that is used to help determine what Components an Entity must contain so a specific EntitySystem can process it EntitySystemManager - Manages all EntitySystems within a Scene EntityManager - Manages entities (i.e. holds all Entities, used to determine whether an Entity has been changed, enables/disables them, etc.) EntityFactory - Creates (and destroys) entities and assigns an ID to them Scene - Contains an EntityManager, EntityFactory, EntitySystemManager and ComponentManager. Has functions to update and initialise the scene. Now in order for an EntitySystem to efficiently know when to check if an Entity is valid for processing (so I can add it to a specific EntitySystem), it must recieve a message from the EntityManager (after a call of activate(Entity& e)). Similarly the EntityManager must know when an Entity is destroyed from the EntityFactory in the Scene, and also the ComponentManager must know when an Entity is created AND destroyed. I do have a Listener/Observer pattern implemented at the moment, but with this pattern I may remove a Listener (which is this case is dependent on the method being called). I mainly have this implemented for specific things related to a game, i.e. Teams, Tagging of entities, etc. So... I was thinking maybe I should call a private method (using friend classes) to send out when an Entity has been activated, deleted, etc. i.e. taken from my EntityFactory void EntityFactory::killEntity(Entity& e) { // if the entity doesn't exsist in the entity manager within the scene if(!getScene()->getEntityManager().doesExsist(e)) { return; // go back to the caller! (should throw an exception or something..) } // tell the ComponentManager and the EntityManager that we killed an Entity getScene()->getComponentManager().doOnEntityWillDie(e); getScene()->getEntityManager().doOnEntityWillDie(e); // notify the listners for(Mouth::iterator i = getMouth().begin(); i != getMouth().end(); ++i) { (*i)->onEntityWillDie(*this, e); } _idPool.addId(e.getId()); // add the ID to the pool delete &e; // delete the entity } As you can see on the lines where I am telling the ComponentManager and the EntityManager that an Entity will die, I am calling a method to make sure it handles it appropriately. Now I realise I could do this without calling it explicitly, with the help of that for loop notifying all listener objects connected to the EntityFactory's Mouth (an object used to tell listeners that there's an event), however is this a good idea (good design, or what)? I've gone over the PROS and CONS, I just can't decide what I want to do. Calling Explicitly: PROS Faster? Since these functions are explicitly called, they can't be "removed" CONS Not flexible Bad design? (friend functions) Calling through Listener objects (i.e. ComponentManager/EntityManager inherits from a EntityFactoryListener) PROS More Flexible? Better Design? CONS Slower? (virtual functions) Listeners can be removed, i.e. may be removed and not get called again during the program, which could cause in a crash. P.S. If you wish to view my current source code, I am hosting it on BitBucket.

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

  - by mwhite

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

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• A layout for maven project with a patched dependency

  - by zamza

  Suppose, I have an opensource project that depends on some library, that must be patched in order to fix some issues. How do I do that? My ideas are: Have that library sources set up as a module, keep them in my vcs. Pros: simple. Cons: some third party sources in my repo, might slow down build process, hard to find a patched place (though can be fixed in README) Have a module, like in 1, but keep patched source files only, compile them with orignal library jar in classpath and somehow replace *.class files in library jar on build. Pros: builds faster, easy to find patched places. Cons: hard to configure, that jar hackery is non-obvious (library jar in repository and in my project assembly would be different) Keep patched *.class files in main/resources, and replace on packaging like in 2). Pros: almost none. Cons: binaries in vcs, hard to recompile a patched class as patch compilation is not automated. One nice solution is to create a distinct project with patched library sources, and deploy it on local/enterprise repository with -patched qualifier. But that would not fit for an opensourced project that is meant to be easily buildable by anyone who checks out its sources. Or should I just say "and also, before you build my project, please check out that stuff and run mvn install".

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• make emacs in a terminal use dark colors and not light font-lock colors

  - by vy32

  I am using emacs on MacOS 10.6 with Terminal. I have a white background. It's very hard to read quoted C++ strings. They are coming up in pale green. Keywords are in turquoise. After searching through the source I cam across cpp.el and have determined that I am using the cpp-face-light-name-list instead of cpp-face-dark-name-list. Apparently this function is supposed to chose the correct list based on the background color: (defcustom cpp-face-default-list nil "Alist of faces you can choose from for cpp conditionals. Each element has the form (STRING . FACE), where STRING serves as a name (for `cpp-highlight-buffer' only) and FACE is either a face (a symbol) or a cons cell (background-color . COLOR)." :type '(repeat (cons string (choice face (cons (const background-color) string)))) :group 'cpp) But it doesn't seem to be working. What should I put in my .emacs file so that I get the cpp-face-dark-list instead of cpp-face-light-list? Thanks!

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• Scheme homework Black jack help....

  - by octavio

  So I need to do a game of blackjack simulator, butt can't seem to figure out whats wrong with the shuffle it's suppose to take a card randomly from the pack the put it on top of the pack. The delete it from the rest. so : (ace)(2)(3)(4)(5)...(k) if random card is let say 5 (5)(ace)(2)(3)(4)(5)...(k) then it deletes the 2nd 5 (5)(ace)(2)(3)(4)(6)...(k) here is the code: (define deck '((A . C) (2 . C) (3 . C) (4 . C) (5 . C) (6 . C) (7 . C) (8 . C) (9 . C) (10 . C) (V . C) (Q . C) (K . C))) ;auxilliary function for shuffle let you randomly select a card. (define shuffAux (lambda (t) (define cardR (lambda (t) (list-ref t (random 13)))) (cardR t))) ;auxilliary function used to remove the card after the car to prevent you from removing the randomly selected from the car(begining of the deck). (define (removeDupC card deck) (delete card (cdr deck)) ) (define shuffle2ndtry (lambda (deck seed) (define do-shuffle (lambda (deck seed) (if (> seed 0)( (cons (shuffAux deck) deck) (removeDupC (car deck) deck) (- 1 seed)) (write deck) ) ) ) (do-shuffle deck seed))) (define (shuffle deck seed) (define cards (cons (shuffAux deck) deck)) (write cards) (case (> seed 0) [(#t) (removeDupC (car cards) (cdr cards)) (shuffle cards (- seed 1))] [(#f) (write cards)])) (define random (let ((seed 0) (a 3141592653) (c 2718281829) (m (expt 2 35))) (lambda (limit) (cond ((and (integer? limit)) (set! seed (modulo (+ (* seed a) c) m)) (quotient (* seed limit) m)) (else (/ (* limit (random 34359738368)) 34359738368)))))) ;function in which you can delete an element from the list. (define delete (lambda (item list) (cond ((equal? item (car list)) (cdr list)) (else (cons (car list) (delete item (cdr list))))))) (

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• Database structure - is mySQL the right choice?

  - by Industrial

  Hi everyone, We are currently planning the database structure of a quite complex e-commerce web app that has flexibility as it's main cornerstone. Our app features a large amount of data (products) and we have run into a slight headache trying to keep performance high without compromizing normalization rules in the database, or leaving our highly beloved flexibility concept behind when integrating product options (also widely known as product attributes or parameters). Based on various references and sources available, we have made up lists on pros and cons of all major and well known database patterns to solve this. After comparing these, we have come up with two final alternatives: EAV (Entity-attribute-value model) : Pros: Database is used for all sorting. Cons: All related queries will include a number of joins between multiple tables in order to complete the collection of data. SLOB (Serialized LOB, also known as Facade?) : Pros: Very flexible. Keeping the number of necessary joins low compared to a EAV design pattern. Easy to update/add/remove data from each product. Cons: All sorting will be done by the application instead of the database. Will use lots of performance (memory?) when big datasets is processed by a large number of users. Our main questions: Which pattern/structure would you use, or maybe even a different solution? Is there better databases besides mySQL available nowadays to accomplish what we want? Thanks a lot! Reference: http://stackoverflow.com/questions/695752/product-table-many-kinds-of-product-each-product-has-many-parameters

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• Whats wrong with this HQL query?

  - by ManBugra

  did i encounter a hibernate bug or do i have an error i dont see: select enty.number from EntityAliasName enty where enty.myId in ( select cons.myId from Consens cons where cons.number in ( select ord.number from Orders ord where ord.customer = :customer and ord.creationDate < ( select max(ord.creationDate) from Orders ord where ord.customer = :customer ) ) ) what i do get is the following: org.hibernate.util.StringHelper.root(StringHelper.java:257) Caused by: java.lang.NullPointerException at org.hibernate.util.StringHelper.root(StringHelper.java:257) at org.hibernate.persister.entity.AbstractEntityPersister.getSubclassPropertyTableNumber(AbstractEntityPersister.java:1391) at org.hibernate.persister.entity.BasicEntityPropertyMapping.toColumns(BasicEntityPropertyMapping.java:54) at org.hibernate.persister.entity.AbstractEntityPersister.toColumns(AbstractEntityPersister.java:1367) at org.hibernate.hql.ast.tree.FromElement.getIdentityColumn(FromElement.java:320) at org.hibernate.hql.ast.tree.IdentNode.resolveAsAlias(IdentNode.java:154) at org.hibernate.hql.ast.tree.IdentNode.resolve(IdentNode.java:100) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:117) at org.hibernate.hql.ast.tree.FromReferenceNode.resolve(FromReferenceNode.java:113) at org.hibernate.hql.ast.HqlSqlWalker.resolve(HqlSqlWalker.java:854) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1172) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRefLhs(HqlSqlBaseWalker.java:5167) at org.hibernate.hql.antlr.HqlSqlBaseWalker.propertyRef(HqlSqlBaseWalker.java:1133) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExpr(HqlSqlBaseWalker.java:1993) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectExprList(HqlSqlBaseWalker.java:1932) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectClause(HqlSqlBaseWalker.java:1476) at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:580) at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:288) at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:231) at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:254) at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:185) at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:136) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101) at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80) at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:94) at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:484) at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:394) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341) using: Hibernate 3.3.2.GA / postgresql

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• Does isEmpty method in Stream evaluate the whole Stream?

  - by abhin4v

  In Scala, does calling isEmtpy method on an instance of Stream class cause the stream to be evaluated completely? My code is like this: import Stream.cons private val odds: Stream[Int] = cons(3, odds.map(_ + 2)) private val primes: Stream[Int] = cons(2, odds filter isPrime) private def isPrime(n: Int): Boolean = n match { case 1 => false case 2 => true case 3 => true case 5 => true case 7 => true case x if n % 3 == 0 => false case x if n % 5 == 0 => false case x if n % 7 == 0 => false case x if (x + 1) % 6 == 0 || (x - 1) % 6 == 0 => true case x => primeDivisors(x) isEmpty } import Math.{sqrt, ceil} private def primeDivisors(n: Int) = primes takeWhile { _ <= ceil(sqrt(n))} filter {n % _ == 0 } So, does the call to isEmpty on the line case x => primeDivisors(x) isEmpty cause all the prime divisors to be evaluated or only the first one?

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• Sharing a COM port over TCP

  - by guinness

  What would be a simple design pattern for sharing a COM port over TCP to multiple clients? For example, a local GPS device that could transmit co-ordinates to remote hosts in realtime. So I need a program that would open the serial port and accept multiple TCP connections like: class Program { public static void Main(string[] args) { SerialPort sp = new SerialPort("COM4", 19200, Parity.None, 8, StopBits.One); Socket srv = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); srv.Bind(new IPEndPoint(IPAddress.Any, 8000)); srv.Listen(20); while (true) { Socket soc = srv.Accept(); new Connection(soc); } } } I would then need a class to handle the communication between connected clients, allowing them all to see the data and keeping it synchronized so client commands are received in sequence: class Connection { static object lck = new object(); static List<Connection> cons = new List<Connection>(); public Socket socket; public StreamReader reader; public StreamWriter writer; public Connection(Socket soc) { this.socket = soc; this.reader = new StreamReader(new NetworkStream(soc, false)); this.writer = new StreamWriter(new NetworkStream(soc, true)); new Thread(ClientLoop).Start(); } void ClientLoop() { lock (lck) { connections.Add(this); } while (true) { lock (lck) { string line = reader.ReadLine(); if (String.IsNullOrEmpty(line)) break; foreach (Connection con in cons) con.writer.WriteLine(line); } } lock (lck) { cons.Remove(this); socket.Close(); } } } The problem I'm struggling to resolve is how to facilitate communication between the SerialPort instance and the threads. I'm not certain that the above code is the best way forward, so does anybody have another solution (the simpler the better)?

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• Groovy as a substitute for Java when using BigDecimal?

  - by geejay

  I have just completed an evaluation of Java, Groovy and Scala. The factors I considered were: readability, precision The factors I would like to know: performance, ease of integration I needed a BigDecimal level of precision. Here are my results: Java void someOp() { BigDecimal del_theta_1 = toDec(6); BigDecimal del_theta_2 = toDec(2); BigDecimal del_theta_m = toDec(0); del_theta_m = abs(del_theta_1.subtract(del_theta_2)) .divide(log(del_theta_1.divide(del_theta_2))); } Groovy void someOp() { def del_theta_1 = 6.0 def del_theta_2 = 2.0 def del_theta_m = 0.0 del_theta_m = Math.abs(del_theta_1 - del_theta_2) / Math.log(del_theta_1 / del_theta_2); } Scala def other(){ var del_theta_1 = toDec(6); var del_theta_2 = toDec(2); var del_theta_m = toDec(0); del_theta_m = ( abs(del_theta_1 - del_theta_2) / log(del_theta_1 / del_theta_2) ) } Note that in Java and Scala I used static imports. Java: Pros: it is Java Cons: no operator overloading (lots o methods), barely readable/codeable Groovy: Pros: default BigDecimal means no visible typing, least surprising BigDecimal support for all operations (division included) Cons: another language to learn Scala: Pros: has operator overloading for BigDecimal Cons: some surprising behaviour with division (fixed with Decimal128), another language to learn

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