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• iTunes Home Sharing only works one way between 2 Windows XP PC's on the same LAN

  - by scunliffe

  Both PC's have the latest iTunes installed. PC (A) can "see" that there is a shared library "B library" but attempts to connect to it return this error message: The shared library "{Username}'s Library" is not responding (-3259) Check that any firewall software running on either the shared computer or this computer has been set to allow communication on port 3689. however the reverse works fine. e.g. PC (B) can "see" shared library "A library" and can access all content. Notes: Both PC's have Home Sharing enabled (turned off/on several times to verify). Both PC's have Windows Firewall turned on, but in the exceptions tab, iTunes is allowed, and Port 3689 is also added as a firewall exception (just in case) Both iTunes accounts have been "authorized" on both PC's Both PC's connect via LAN via D-Link DIR-615 router. In the advanced application rules, iTunes has also been added to allow traffic on port 3689 un-hindered. Is there any other magical setting/configuration option that I should be aware of and set in order to get this to work? I could care less about sharing apps etc. I just want the music sharing to work. Update: Solved! It turns out on PC (B) there were multiple accounts set up. 1 of the accounts had the checkbox checked under the Windows firewall "On" option which states "No exceptions" thus even though it was added to the exception list on the main user account, this other account was blocking access.

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• How do i play nicely with MS SQL/SQL Server 2008

  - by acidzombie24

  Big problem. I have nearly given up. I am trying to port my prototype to use MS SQL so it will work on a server once i get it (the server will be SQL Server 2008, shared, i dont know any more info). So i tried to connect to SQL Server via visual studios IDE and had no luck. I enabled TCP and named pipes and restarted the service (and computer) with still no luck. I remembered about mdf files so i made that after an obstacle of not being able to make the connect string require i figure out visual studio has it in its properties and successfully connected with that. Then i had a problem with nested transactions. After not being able to figure out how to check i wondered if i can configure it to allow it somehow. I always thought all of MS were the same except for limitations but sql server seems to support nested transactions so theres no point trying to work around the problem with .mdf files since i wont need them and really just used it to port the base of my sql code and to check if syntax is correct. I tried installing SQL Server Management Studio since people mentioned it several times (as a solution or at least help). When installing it on windows 7 it says it may not be compatible. After running it, it launched SQL Server Installation Center (64-bit) which doesnt seem to be the same thing as i dont see a way to modify any of my server (networking) configurations or edit user permissions, etc. I am clueless what to do next. Does anyone have any ideas? I'm posting here bc i think my problem is more configurations and sql server then programming.

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• How do you permanently disable the 'This Connection is Untrusted' page on Firefox

  - by TheIronChef9

  I'm going insane. Can someone please help me to COMPLETELY DISABLE the 'This Connection is Untrusted' page on Firefox. Facts: I am running Firefox 23.0 on an Ubuntu machine (downloaded and installed ubuntu today) It is a work computer and I have to use my employer's proxy While visiting Webpages/webapps like Gmail or Google brings up the 'This Connection is Untrusted' page and I have to go through the whole tedious task of selecting 'I understand the Risks' and add Exceptions, etc. etc. The fact is, I don't care about the risks. I would rather this computer melt into the ground than have to see that page ever again. I want to dance naked in untrusted pages and not give a damn about the consequences. I just never want to see that page again. Ever. For some sites (eg. wikipedia), the css doesn't load and I end up seeing them in plain text. As a result these sites are completely useless. Wasted hours trying to solve this for stackoverflow.com. These issues happen on the Firefox on my Windows XP machine as well (also using the same proxy). I don't want to export/import certificates or create exceptions for every site that shows this bloody page. I just want this page gone. I don't want Firefox to tell me what's safe and what's not. Also, my system time and date are correct. I've also tried the lies on this page too with no good results. Edit: I've also tried the whole going into the Advance-Certificates-validation setup page and unchecked 'Use the Online Certificate Status Protocol (OCSP) to confirm the current validity of certificates' checkbox. Nothing happened even after restarting firefox or rebooting. I need help. Thanks.

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• Using a "white list" for extracting terms for Text Mining, Part 2

  - by [email protected]

  In my last post, we set the groundwork for extracting specific tokens from a white list using a CTXRULE index. In this post, we will populate a table with the extracted tokens and produce a case table suitable for clustering with Oracle Data Mining. Our corpus of documents will be stored in a database table that is defined as create table documents(id NUMBER, text VARCHAR2(4000)); However, any suitable Oracle Text-accepted data type can be used for the text. We then create a table to contain the extracted tokens. The id column contains the unique identifier (or case id) of the document. The token column contains the extracted token. Note that a given document many have many tokens, so there will be one row per token for a given document. create table extracted_tokens (id NUMBER, token VARCHAR2(4000)); The next step is to iterate over the documents and extract the matching tokens using the index and insert them into our token table. We use the MATCHES function for matching the query_string from my_thesaurus_rules with the text. DECLARE     cursor c2 is       select id, text       from documents; BEGIN     for r_c2 in c2 loop        insert into extracted_tokens          select r_c2.id id, main_term token          from my_thesaurus_rules          where matches(query_string,                        r_c2.text)>0;     end loop; END; Now that we have the tokens, we can compute the term frequency - inverse document frequency (TF-IDF) for each token of each document. create table extracted_tokens_tfidf as   with num_docs as (select count(distinct id) doc_cnt                     from extracted_tokens),        tf       as (select a.id, a.token,                            a.token_cnt/b.num_tokens token_freq                     from                        (select id, token, count(*) token_cnt                        from extracted_tokens                        group by id, token) a,                       (select id, count(*) num_tokens                        from extracted_tokens                        group by id) b                     where a.id=b.id),        doc_freq as (select token, count(*) overall_token_cnt                     from extracted_tokens                     group by token)   select tf.id, tf.token,          token_freq * ln(doc_cnt/df.overall_token_cnt) tf_idf   from num_docs,        tf,        doc_freq df   where df.token=tf.token; From the WITH clause, the num_docs query simply counts the number of documents in the corpus. The tf query computes the term (token) frequency by computing the number of times each token appears in a document and divides that by the number of tokens found in the document. The doc_req query counts the number of times the token appears overall in the corpus. In the SELECT clause, we compute the tf_idf. Next, we create the nested table required to produce one record per case, where a case corresponds to an individual document. Here, we COLLECT all the tokens for a given document into the nested column extracted_tokens_tfidf_1. CREATE TABLE extracted_tokens_tfidf_nt              NESTED TABLE extracted_tokens_tfidf_1                  STORE AS extracted_tokens_tfidf_tab AS              select id,                     cast(collect(DM_NESTED_NUMERICAL(token,tf_idf)) as DM_NESTED_NUMERICALS) extracted_tokens_tfidf_1              from extracted_tokens_tfidf              group by id;   To build the clustering model, we create a settings table and then insert the various settings. Most notable are the number of clusters (20), using cosine distance which is better for text, turning off auto data preparation since the values are ready for mining, the number of iterations (20) to get a better model, and the split criterion of size for clusters that are roughly balanced in number of cases assigned. CREATE TABLE km_settings (setting_name  VARCHAR2(30), setting_value VARCHAR2(30)); BEGIN  INSERT INTO km_settings (setting_name, setting_value) VALUES     VALUES (dbms_data_mining.clus_num_clusters, 20);  INSERT INTO km_settings (setting_name, setting_value)     VALUES (dbms_data_mining.kmns_distance, dbms_data_mining.kmns_cosine);   INSERT INTO km_settings (setting_name, setting_value) VALUES     VALUES (dbms_data_mining.prep_auto,dbms_data_mining.prep_auto_off);   INSERT INTO km_settings (setting_name, setting_value) VALUES     VALUES (dbms_data_mining.kmns_iterations,20);   INSERT INTO km_settings (setting_name, setting_value) VALUES     VALUES (dbms_data_mining.kmns_split_criterion,dbms_data_mining.kmns_size);   COMMIT; END; With this in place, we can now build the clustering model. BEGIN     DBMS_DATA_MINING.CREATE_MODEL(     model_name          => 'TEXT_CLUSTERING_MODEL',     mining_function     => dbms_data_mining.clustering,     data_table_name     => 'extracted_tokens_tfidf_nt',     case_id_column_name => 'id',     settings_table_name => 'km_settings'); END;To generate cluster names from this model, check out my earlier post on that topic.

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• VLOOKUP in Excel, part 2: Using VLOOKUP without a database

  - by Mark Virtue

  In a recent article, we introduced the Excel function called VLOOKUP and explained how it could be used to retrieve information from a database into a cell in a local worksheet.  In that article we mentioned that there were two uses for VLOOKUP, and only one of them dealt with querying databases.  In this article, the second and final in the VLOOKUP series, we examine this other, lesser known use for the VLOOKUP function. If you haven’t already done so, please read the first VLOOKUP article – this article will assume that many of the concepts explained in that article are already known to the reader. When working with databases, VLOOKUP is passed a “unique identifier” that serves to identify which data record we wish to find in the database (e.g. a product code or customer ID).  This unique identifier must exist in the database, otherwise VLOOKUP returns us an error.  In this article, we will examine a way of using VLOOKUP where the identifier doesn’t need to exist in the database at all.  It’s almost as if VLOOKUP can adopt a “near enough is good enough” approach to returning the data we’re looking for.  In certain circumstances, this is exactly what we need. We will illustrate this article with a real-world example – that of calculating the commissions that are generated on a set of sales figures.  We will start with a very simple scenario, and then progressively make it more complex, until the only rational solution to the problem is to use VLOOKUP.  The initial scenario in our fictitious company works like this:  If a salesperson creates more than $30,000 worth of sales in a given year, the commission they earn on those sales is 30%.  Otherwise their commission is only 20%.  So far this is a pretty simple worksheet: To use this worksheet, the salesperson enters their sales figures in cell B1, and the formula in cell B2 calculates the correct commission rate they are entitled to receive, which is used in cell B3 to calculate the total commission that the salesperson is owed (which is a simple multiplication of B1 and B2). The cell B2 contains the only interesting part of this worksheet – the formula for deciding which commission rate to use: the one below the threshold of $30,000, or the one above the threshold.  This formula makes use of the Excel function called IF.  For those readers that are not familiar with IF, it works like this: IF(condition,value if true,value if false) Where the condition is an expression that evaluates to either true or false.  In the example above, the condition is the expression B1<B5, which can be read as “Is B1 less than B5?”, or, put another way, “Are the total sales less than the threshold”.  If the answer to this question is “yes” (true), then we use the value if true parameter of the function, namely B6 in this case – the commission rate if the sales total was below the threshold.  If the answer to the question is “no” (false), then we use the value if false parameter of the function, namely B7 in this case – the commission rate if the sales total was above the threshold. As you can see, using a sales total of $20,000 gives us a commission rate of 20% in cell B2.  If we enter a value of $40,000, we get a different commission rate: So our spreadsheet is working. Let’s make it more complex.  Let’s introduce a second threshold:  If the salesperson earns more than $40,000, then their commission rate increases to 40%: Easy enough to understand in the real world, but in cell B2 our formula is getting more complex.  If you look closely at the formula, you’ll see that the third parameter of the original IF function (the value if false) is now an entire IF function in its own right.  This is called a nested function (a function within a function).  It’s perfectly valid in Excel (it even works!), but it’s harder to read and understand. We’re not going to go into the nuts and bolts of how and why this works, nor will we examine the nuances of nested functions.  This is a tutorial on VLOOKUP, not on Excel in general. Anyway, it gets worse!  What about when we decide that if they earn more than $50,000 then they’re entitled to 50% commission, and if they earn more than $60,000 then they’re entitled to 60% commission? Now the formula in cell B2, while correct, has become virtually unreadable.  No-one should have to write formulae where the functions are nested four levels deep!  Surely there must be a simpler way? There certainly is.  VLOOKUP to the rescue! Let’s redesign the worksheet a bit.  We’ll keep all the same figures, but organize it in a new way, a more tabular way: Take a moment and verify for yourself that the new Rate Table works exactly the same as the series of thresholds above. Conceptually, what we’re about to do is use VLOOKUP to look up the salesperson’s sales total (from B1) in the rate table and return to us the corresponding commission rate.  Note that the salesperson may have indeed created sales that are not one of the five values in the rate table ($0, $30,000, $40,000, $50,000 or $60,000).  They may have created sales of $34,988.  It’s important to note that $34,988 does not appear in the rate table.  Let’s see if VLOOKUP can solve our problem anyway… We select cell B2 (the location we want to put our formula), and then insert the VLOOKUP function from the Formulas tab: The Function Arguments box for VLOOKUP appears.  We fill in the arguments (parameters) one by one, starting with the Lookup_value, which is, in this case, the sales total from cell B1.  We place the cursor in the Lookup_value field and then click once on cell B1: Next we need to specify to VLOOKUP what table to lookup this data in.  In this example, it’s the rate table, of course.  We place the cursor in the Table_array field, and then highlight the entire rate table – excluding the headings: Next we must specify which column in the table contains the information we want our formula to return to us.  In this case we want the commission rate, which is found in the second column in the table, so we therefore enter a 2 into the Col_index_num field: Finally we enter a value in the Range_lookup field. Important:  It is the use of this field that differentiates the two ways of using VLOOKUP.  To use VLOOKUP with a database, this final parameter, Range_lookup, must always be set to FALSE, but with this other use of VLOOKUP, we must either leave it blank or enter a value of TRUE.  When using VLOOKUP, it is vital that you make the correct choice for this final parameter. To be explicit, we will enter a value of true in the Range_lookup field.  It would also be fine to leave it blank, as this is the default value: We have completed all the parameters.  We now click the OK button, and Excel builds our VLOOKUP formula for us: If we experiment with a few different sales total amounts, we can satisfy ourselves that the formula is working. Conclusion In the “database” version of VLOOKUP, where the Range_lookup parameter is FALSE, the value passed in the first parameter (Lookup_value) must be present in the database.  In other words, we’re looking for an exact match. But in this other use of VLOOKUP, we are not necessarily looking for an exact match.  In this case, “near enough is good enough”.  But what do we mean by “near enough”?  Let’s use an example:  When searching for a commission rate on a sales total of $34,988, our VLOOKUP formula will return us a value of 30%, which is the correct answer.  Why did it choose the row in the table containing 30% ?  What, in fact, does “near enough” mean in this case?  Let’s be precise: When Range_lookup is set to TRUE (or omitted), VLOOKUP will look in column 1 and match the highest value that is not greater than the Lookup_value parameter. It’s also important to note that for this system to work, the table must be sorted in ascending order on column 1! If you would like to practice with VLOOKUP, the sample file illustrated in this article can be downloaded from here. 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• Operator of the week - Assert

  - by Fabiano Amorim

  Well my friends, I was wondering how to help you in a practical way to understand execution plans. So I think I'll talk about the Showplan Operators. Showplan Operators are used by the Query Optimizer (QO) to build the query plan in order to perform a specified operation. A query plan will consist of many physical operators. The Query Optimizer uses a simple language that represents each physical operation by an operator, and each operator is represented in the graphical execution plan by an icon. I'll try to talk about one operator every week, but so as to avoid having to continue to write about these operators for years, I'll mention only of those that are more common: The first being the Assert. The Assert is used to verify a certain condition, it validates a Constraint on every row to ensure that the condition was met. If, for example, our DDL includes a check constraint which specifies only two valid values for a column, the Assert will, for every row, validate the value passed to the column to ensure that input is consistent with the check constraint. Assert  and Check Constraints: Let's see where the SQL Server uses that information in practice. Take the following T-SQL: IF OBJECT_ID('Tab1') IS NOT NULL   DROP TABLE Tab1 GO CREATE TABLE Tab1(ID Integer, Gender CHAR(1))  GO  ALTER TABLE TAB1 ADD CONSTRAINT ck_Gender_M_F CHECK(Gender IN('M','F'))  GO INSERT INTO Tab1(ID, Gender) VALUES(1,'X') GO To the command above the SQL Server has generated the following execution plan: As we can see, the execution plan uses the Assert operator to check that the inserted value doesn't violate the Check Constraint. In this specific case, the Assert applies the rule, 'if the value is different to "F" and different to "M" than return 0 otherwise returns NULL'. The Assert operator is programmed to show an error if the returned value is not NULL; in other words, the returned value is not a "M" or "F". Assert checking Foreign Keys Now let's take a look at an example where the Assert is used to validate a foreign key constraint. Suppose we have this  query: ALTER TABLE Tab1 ADD ID_Genders INT GO  IF OBJECT_ID('Tab2') IS NOT NULL   DROP TABLE Tab2 GO CREATE TABLE Tab2(ID Integer PRIMARY KEY, Gender CHAR(1))  GO  INSERT INTO Tab2(ID, Gender) VALUES(1, 'F') INSERT INTO Tab2(ID, Gender) VALUES(2, 'M') INSERT INTO Tab2(ID, Gender) VALUES(3, 'N') GO  ALTER TABLE Tab1 ADD CONSTRAINT fk_Tab2 FOREIGN KEY (ID_Genders) REFERENCES Tab2(ID) GO  INSERT INTO Tab1(ID, ID_Genders, Gender) VALUES(1, 4, 'X') Let's look at the text execution plan to see what these Assert operators were doing. To see the text execution plan just execute SET SHOWPLAN_TEXT ON before run the insert command. |--Assert(WHERE:(CASE WHEN NOT [Pass1008] AND [Expr1007] IS NULL THEN (0) ELSE NULL END))      |--Nested Loops(Left Semi Join, PASSTHRU:([Tab1].[ID_Genders] IS NULL), OUTER REFERENCES:([Tab1].[ID_Genders]), DEFINE:([Expr1007] = [PROBE VALUE]))           |--Assert(WHERE:(CASE WHEN [Tab1].[Gender]<>'F' AND [Tab1].[Gender]<>'M' THEN (0) ELSE NULL END))           |    |--Clustered Index Insert(OBJECT:([Tab1].[PK]), SET:([Tab1].[ID] = RaiseIfNullInsert([@1]),[Tab1].[ID_Genders] = [@2],[Tab1].[Gender] = [Expr1003]), DEFINE:([Expr1003]=CONVERT_IMPLICIT(char(1),[@3],0)))           |--Clustered Index Seek(OBJECT:([Tab2].[PK]), SEEK:([Tab2].[ID]=[Tab1].[ID_Genders]) ORDERED FORWARD) Here we can see the Assert operator twice, first (looking down to up in the text plan and the right to left in the graphical plan) validating the Check Constraint. The same concept showed above is used, if the exit value is "0" than keep running the query, but if NULL is returned shows an exception. The second Assert is validating the result of the Tab1 and Tab2 join. It is interesting to see the "[Expr1007] IS NULL". To understand that you need to know what this Expr1007 is, look at the Probe Value (green text) in the text plan and you will see that it is the result of the join. If the value passed to the INSERT at the column ID_Gender exists in the table Tab2, then that probe will return the join value; otherwise it will return NULL. So the Assert is checking the value of the search at the Tab2; if the value that is passed to the INSERT is not found  then Assert will show one exception. If the value passed to the column ID_Genders is NULL than the SQL can't show a exception, in that case it returns "0" and keeps running the query. If you run the INSERT above, the SQL will show an exception because of the "X" value, but if you change the "X" to "F" and run again, it will show an exception because of the value "4". If you change the value "4" to NULL, 1, 2 or 3 the insert will be executed without any error. Assert checking a SubQuery: The Assert operator is also used to check one subquery. As we know, one scalar subquery can't validly return more than one value: Sometimes, however, a  mistake happens, and a subquery attempts to return more than one value . Here the Assert comes into play by validating the condition that a scalar subquery returns just one value. Take the following query: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1), 'F')    |--Assert(WHERE:(CASE WHEN NOT [Pass1016] AND [Expr1015] IS NULL THEN (0) ELSE NULL END))        |--Nested Loops(Left Semi Join, PASSTHRU:([tempdb].[dbo].[Tab1].[ID_TipoSexo] IS NULL), OUTER REFERENCES:([tempdb].[dbo].[Tab1].[ID_TipoSexo]), DEFINE:([Expr1015] = [PROBE VALUE]))              |--Assert(WHERE:([Expr1017]))             |    |--Compute Scalar(DEFINE:([Expr1017]=CASE WHEN [tempdb].[dbo].[Tab1].[Sexo]<>'F' AND [tempdb].[dbo].[Tab1].[Sexo]<>'M' THEN (0) ELSE NULL END))              |         |--Clustered Index Insert(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]), SET:([tempdb].[dbo].[Tab1].[ID_TipoSexo] = [Expr1008],[tempdb].[dbo].[Tab1].[Sexo] = [Expr1009],[tempdb].[dbo].[Tab1].[ID] = [Expr1003]))              |              |--Top(TOP EXPRESSION:((1)))              |                   |--Compute Scalar(DEFINE:([Expr1008]=[Expr1014], [Expr1009]='F'))              |                        |--Nested Loops(Left Outer Join)              |                             |--Compute Scalar(DEFINE:([Expr1003]=getidentity((1856985942),(2),NULL)))              |                             |    |--Constant Scan              |                             |--Assert(WHERE:(CASE WHEN [Expr1013]>(1) THEN (0) ELSE NULL END))              |                                  |--Stream Aggregate(DEFINE:([Expr1013]=Count(*), [Expr1014]=ANY([tempdb].[dbo].[Tab1].[ID_TipoSexo])))             |                                       |--Clustered Index Scan(OBJECT:([tempdb].[dbo].[Tab1].[PK__Tab1__3214EC277097A3C8]))              |--Clustered Index Seek(OBJECT:([tempdb].[dbo].[Tab2].[PK__Tab2__3214EC27755C58E5]), SEEK:([tempdb].[dbo].[Tab2].[ID]=[tempdb].[dbo].[Tab1].[ID_TipoSexo]) ORDERED FORWARD)  You can see from this text showplan that SQL Server as generated a Stream Aggregate to count how many rows the SubQuery will return, This value is then passed to the Assert which then does its job by checking its validity. Is very interesting to see that  the Query Optimizer is smart enough be able to avoid using assert operators when they are not necessary. For instance: INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT ID_TipoSexo FROM Tab1 WHERE ID = 1), 'F') INSERT INTO Tab1(ID_TipoSexo, Sexo) VALUES((SELECT TOP 1 ID_TipoSexo FROM Tab1), 'F')  For both these INSERTs, the Query Optimiser is smart enough to know that only one row will ever be returned, so there is no need to use the Assert. Well, that's all folks, I see you next week with more "Operators". Cheers, Fabiano

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• The Stub Proto: Not Just For Stub Objects Anymore

  - by user9154181

  One of the great pleasures of programming is to invent something for a narrow purpose, and then to realize that it is a general solution to a broader problem. In hindsight, these things seem perfectly natural and obvious. The stub proto area used to build the core Solaris consolidation has turned out to be one of those things. As discussed in an earlier article, the stub proto area was invented as part of the effort to use stub objects to build the core ON consolidation. Its purpose was merely as a place to hold stub objects. However, we keep finding other uses for it. It turns out that the stub proto should be more properly thought of as an auxiliary place to put things that we would like to put into the proto to help us build the product, but which we do not wish to package or deliver to the end user. Stub objects are one example, but private lint libraries, header files, archives, and relocatable objects, are all examples of things that might profitably go into the stub proto. Without a stub proto, these items were handled in a variety of ad hoc ways: If one part of the workspace needed private header files, libraries, or other such items, it might modify its Makefile to reach up and over to the place in the workspace where those things live and use them from there. There are several problems with this: Each component invents its own approach, meaning that programmers maintaining the system have to invest extra effort to understand what things mean. In the past, this has created makefile ghettos in which only the person who wrote the makefiles feels confident to modify them, while everyone else ignores them. This causes many difficulties and benefits no one. These interdependencies are not obvious to the make, utility, and can lead to races. They are not obvious to the human reader, who may therefore not realize that they exist, and break them. Our policy in ON is not to deliver files into the proto unless those files are intended to be packaged and delivered to the end user. However, sometimes non-shipping files were copied into the proto anyway, causing a different set of problems: It requires a long list of exceptions to silence our normal unused proto item error checking. In the past, we have accidentally shipped files that we did not intend to deliver to the end user. Mixing cruft with valuable items makes it hard to discern which is which. The stub proto area offers a convenient and robust solution. Files needed to build the workspace that are not delivered to the end user can instead be installed into the stub proto. No special exceptions or custom make rules are needed, and the intent is always clear. We are already accessing some private lint libraries and compilation symlinks in this manner. Ultimately, I'd like to see all of the files in the proto that have a packaging exception delivered to the stub proto instead, and for the elimination of all existing special case makefile rules. This would include shared objects, header files, and lint libraries. I don't expect this to happen overnight — it will be a long term case by case project, but the overall trend is clear. The Stub Proto, -z assert_deflib, And The End Of Accidental System Object Linking We recently used the stub proto to solve an annoying build issue that goes back to the earliest days of Solaris: How to ensure that we're linking to the OS bits we're building instead of to those from the running system. The Solaris product is made up of objects and files from a number of different consolidations, each of which is built separately from the others from an independent code base called a gate. The core Solaris OS consolidation is ON, which stands for "Operating System and Networking". You will frequently also see ON called the OSnet. There are consolidations for X11 graphics, the desktop environment, open source utilities, compilers and development tools, and many others. The collection of consolidations that make up Solaris is known as the "Wad Of Stuff", usually referred to simply as the WOS. None of these consolidations is self contained. Even the core ON consolidation has some dependencies on libraries that come from other consolidations. The build server used to build the OSnet must be running a relatively recent version of Solaris, which means that its objects will be very similar to the new ones being built. However, it is necessarily true that the build system objects will always be a little behind, and that incompatible differences may exist. The objects built by the OSnet link to other objects. Some of these dependencies come from the OSnet, while others come from other consolidations. The objects from other consolidations are provided by the standard library directories on the build system (/lib, /usr/lib). The objects from the OSnet itself are supposed to come from the proto areas in the workspace, and not from the build server. In order to achieve this, we make use of the -L command line option to the link-editor. The link-editor finds dependencies by looking in the directories specified by the caller using the -L command line option. If the desired dependency is not found in one of these locations, ld will then fall back to looking at the default locations (/lib, /usr/lib). In order to use OSnet objects from the workspace instead of the system, while still accessing non-OSnet objects from the system, our Makefiles set -L link-editor options that point at the workspace proto areas. In general, this works well and dependencies are found in the right places. However, there have always been failures: Building objects in the wrong order might mean that an OSnet dependency hasn't been built before an object that needs it. If so, the dependency will not be seen in the proto, and the link-editor will silently fall back to the one on the build server. Errors in the makefiles can wipe out the -L options that our top level makefiles establish to cause ld to look at the workspace proto first. In this case, all objects will be found on the build server. These failures were rarely if ever caught. As I mentioned earlier, the objects on the build server are generally quite close to the objects built in the workspace. If they offer compatible linking interfaces, then the objects that link to them will behave properly, and no issue will ever be seen. However, if they do not offer compatible linking interfaces, the failure modes can be puzzling and hard to pin down. Either way, there won't be a compile-time warning or error. The advent of the stub proto eliminated the first type of failure. With stub objects, there is no dependency ordering, and the necessary stub object dependency will always be in place for any OSnet object that needs it. However, makefile errors do still occur, and so, the second form of error was still possible. While working on the stub object project, we realized that the stub proto was also the key to solving the second form of failure caused by makefile errors: Due to the way we set the -L options to point at our workspace proto areas, any valid object from the OSnet should be found via a path specified by -L, and not from the default locations (/lib, /usr/lib). Any OSnet object found via the default locations means that we've linked to the build server, which is an error we'd like to catch. Non-OSnet objects don't exist in the proto areas, and so are found via the default paths. However, if we were to create a symlink in the stub proto pointing at each non-OSnet dependency that we require, then the non-OSnet objects would also be found via the paths specified by -L, and not from the link-editor defaults. Given the above, we should not find any dependency objects from the link-editor defaults. Any dependency found via the link-editor defaults means that we have a Makefile error, and that we are linking to the build server inappropriately. All we need to make use of this fact is a linker option to produce a warning when it happens. Although warnings are nice, we in the OSnet have a zero tolerance policy for build noise. The -z fatal-warnings option that was recently introduced with -z guidance can be used to turn the warnings into fatal build errors, forcing the programmer to fix them. This was too easy to resist. I integrated 7021198 ld option to warn when link accesses a library via default path PSARC/2011/068 ld -z assert-deflib option into snv_161 (February 2011), shortly after the stub proto was introduced into ON. This putback introduced the -z assert-deflib option to the link-editor: -z assert-deflib=[libname] Enables warning messages for libraries specified with the -l command line option that are found by examining the default search paths provided by the link-editor. If a libname value is provided, the default library warning feature is enabled, and the specified library is added to a list of libraries for which no warnings will be issued. Multiple -z assert-deflib options can be specified in order to specify multiple libraries for which warnings should not be issued. The libname value should be the name of the library file, as found by the link-editor, without any path components. For example, the following enables default library warnings, and excludes the standard C library. ld ... -z assert-deflib=libc.so ... -z assert-deflib is a specialized option, primarily of interest in build environments where multiple objects with the same name exist and tight control over the library used is required. If is not intended for general use. Note that the definition of -z assert-deflib allows for exceptions to be specified as arguments to the option. In general, the idea of using a symlink from the stub proto is superior because it does not clutter up the link command with a long list of objects. When building the OSnet, we usually use the plain from of -z deflib, and make symlinks for the non-OSnet dependencies. The exception to this are dependencies supplied by the compiler itself, which are usually found at whatever arbitrary location the compiler happens to be installed at. To handle these special cases, the command line version works better. Following the integration of the link-editor change, I made use of -z assert-deflib in OSnet builds with 7021896 Prevent OSnet from accidentally linking to build system which integrated into snv_162 (March 2011). Turning on -z assert-deflib exposed between 10 and 20 existing errors in our Makefiles, which were all fixed in the same putback. The errors we found in our Makefiles underscore how difficult they can be prevent without an automatic system in place to catch them. Conclusions The stub proto is proving to be a generally useful construct for ON builds that goes beyond serving as a place to hold stub objects. Although invented to hold stub objects, it has already allowed us to simplify a number of previously difficult situations in our makefiles and builds. I expect that we'll find uses for it beyond those described here as we go forward.

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• Unable to import Maven project into IntelliJ IDEA

  - by del

  I'm having problems importing any Maven projects into IntelliJ IDEA. I create an empty Maven project like this: $ mvn archetype:generate -DgroupId=com.mycompany.app -DartifactId=my-app -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false Then I try to open the project in IDEA (File Open Project, then choose the pom.xml). A progress box saying "Reading pom.xml" displays for a few minutes, and then just disappears without opening the project. Looking in the IDEA log, I see some connection timeout exceptions like this: 2012-10-03 11:55:55,483 [ 16981] INFO - ution.rmi.RemoteProcessSupport - Port/ID: 18011/Maven2ServerImpl9407569f 2012-10-03 11:56:58,898 [ 80396] WARN - ution.rmi.RemoteProcessSupport - The cook failed to start due to java.net.ConnectException: Connection timed out 2012-10-03 11:57:55,483 [ 136981] WARN - ution.rmi.RemoteProcessSupport - java.rmi.NotBoundException: _DEAD_HAND_ 2012-10-03 11:57:55,484 [ 136982] WARN - ution.rmi.RemoteProcessSupport - at sun.rmi.registry.RegistryImpl.lookup(RegistryImpl.java:106) 2012-10-03 11:57:55,484 [ 136982] WARN - ution.rmi.RemoteProcessSupport - at com.intellij.execution.rmi.RemoteServer.start(RemoteServer.java:73) 2012-10-03 11:57:55,484 [ 136982] WARN - ution.rmi.RemoteProcessSupport - at org.jetbrains.idea.maven.server.RemoteMavenServer.main(RemoteMavenServer.java:22) 2012-10-03 11:58:01,749 [ 143247] ERROR - com.intellij.ide.IdeEventQueue - Error during dispatching of java.awt.event.MouseEvent[MOUSE_RELEASED,(65,116),absolute(64,140),button=1,modifiers=Button1,clickCount=1] on frame0 java.lang.RuntimeException: Cannot reconnect. at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:82) at org.jetbrains.idea.maven.server.MavenServerManager.applyProfiles(MavenServerManager.java:311) at org.jetbrains.idea.maven.project.MavenProjectReader.applyProfiles(MavenProjectReader.java:369) at org.jetbrains.idea.maven.project.MavenProjectReader.doReadProjectModel(MavenProjectReader.java:98) at org.jetbrains.idea.maven.project.MavenProjectReader.readProject(MavenProjectReader.java:52) at org.jetbrains.idea.maven.project.MavenProject.read(MavenProject.java:405) at org.jetbrains.idea.maven.project.MavenProjectsTree.doUpdate(MavenProjectsTree.java:534) at org.jetbrains.idea.maven.project.MavenProjectsTree.doAdd(MavenProjectsTree.java:481) at org.jetbrains.idea.maven.project.MavenProjectsTree.update(MavenProjectsTree.java:442) at org.jetbrains.idea.maven.project.MavenProjectsTree.updateAll(MavenProjectsTree.java:413) at org.jetbrains.idea.maven.wizards.MavenProjectBuilder.readMavenProjectTree(MavenProjectBuilder.java:198) at org.jetbrains.idea.maven.wizards.MavenProjectBuilder.access$800(MavenProjectBuilder.java:44) at org.jetbrains.idea.maven.wizards.MavenProjectBuilder$3.run(MavenProjectBuilder.java:179) at org.jetbrains.idea.maven.utils.MavenUtil$8.run(MavenUtil.java:388) at com.intellij.openapi.progress.impl.ProgressManagerImpl$TaskRunnable.run(ProgressManagerImpl.java:469) at com.intellij.openapi.progress.impl.ProgressManagerImpl$6.run(ProgressManagerImpl.java:288) at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178) at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:218) at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:169) at com.intellij.openapi.application.impl.ApplicationImpl$8$1.run(ApplicationImpl.java:641) at com.intellij.openapi.application.impl.ApplicationImpl$6.run(ApplicationImpl.java:434) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) at com.intellij.openapi.application.impl.ApplicationImpl$1$1.run(ApplicationImpl.java:145) Caused by: java.rmi.RemoteException: Cannot start maven service; nested exception is: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection timed out at org.jetbrains.idea.maven.server.MavenServerManager.create(MavenServerManager.java:120) at org.jetbrains.idea.maven.server.MavenServerManager.create(MavenServerManager.java:71) at org.jetbrains.idea.maven.server.RemoteObjectWrapper.getOrCreateWrappee(RemoteObjectWrapper.java:41) at org.jetbrains.idea.maven.server.MavenServerManager$8.execute(MavenServerManager.java:314) at org.jetbrains.idea.maven.server.MavenServerManager$8.execute(MavenServerManager.java:311) at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:76) ... 27 more Caused by: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection timed out at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:601) at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:198) at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:184) at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:322) at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source) at com.intellij.execution.rmi.RemoteProcessSupport$2.compute(RemoteProcessSupport.java:215) at com.intellij.execution.rmi.RemoteUtil.executeWithClassLoader(RemoteUtil.java:122) at com.intellij.execution.rmi.RemoteProcessSupport.acquire(RemoteProcessSupport.java:212) at com.intellij.execution.rmi.RemoteProcessSupport.acquire(RemoteProcessSupport.java:133) at org.jetbrains.idea.maven.server.MavenServerManager.create(MavenServerManager.java:117) ... 32 more Caused by: java.net.ConnectException: Connection timed out at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at java.net.Socket.(Socket.java:375) at java.net.Socket.(Socket.java:189) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595) ... 41 more I'm using the latest versions of IDEA (11.1.3) and Maven (3.0.4). Any ideas what I am doing wrong?

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• JSF: Cannot catch ViewExpiredException

  - by ifischer

  I'm developing a JSF 2.0 application on Glassfish v3 and i'm trying to handle the ViewExpiredException. But whatever i do, i always get a Glassfish error report instead of my own error page. To simulate the occurrence of the VEE, i inserted the following function into my backing bean, which fires the VEE. I'm triggering this function from my JSF page through a commandLink. The Code: @Named public class PersonHome { (...) public void throwVEE() { throw new ViewExpiredException(); } } At first i tried it by simply adding an error-page to my web.xml: <error-page> <exception-type>javax.faces.application.ViewExpiredException</exception-type> <location>/error.xhtml</location> </error-page> But this doesn't work, i'm not redirected to error but i'm shown the Glassfish errorpage, which shows a HTTP Status 500 page with the following content: description:The server encountered an internal error () that prevented it from fulfilling this request. exception: javax.servlet.ServletException: javax.faces.application.ViewExpiredException root cause: javax.faces.el.EvaluationException:javax.faces.application.ViewExpiredException root cause:javax.faces.application.ViewExpiredException Next thing i tried was to write ExceptionHandlerFactory and a CustomExceptionHandler, as described in JavaServerFaces 2.0 - The Complete Reference. So i inserted the following tag into faces-config.xml: <factory> <exception-handler-factory> exceptions.ExceptionHandlerFactory </exception-handler-factory> </factory> And added these classes: The factory: package exceptions; import javax.faces.context.ExceptionHandler; public class ExceptionHandlerFactory extends javax.faces.context.ExceptionHandlerFactory { private javax.faces.context.ExceptionHandlerFactory parent; public ExceptionHandlerFactory(javax.faces.context.ExceptionHandlerFactory parent) { this.parent = parent; } @Override public ExceptionHandler getExceptionHandler() { ExceptionHandler result = parent.getExceptionHandler(); result = new CustomExceptionHandler(result); return result; } } The custom exception handler: package exceptions; import java.util.Iterator; import javax.faces.FacesException; import javax.faces.application.NavigationHandler; import javax.faces.application.ViewExpiredException; import javax.faces.context.ExceptionHandler; import javax.faces.context.ExceptionHandlerWrapper; import javax.faces.context.FacesContext; import javax.faces.event.ExceptionQueuedEvent; import javax.faces.event.ExceptionQueuedEventContext; class CustomExceptionHandler extends ExceptionHandlerWrapper { private ExceptionHandler parent; public CustomExceptionHandler(ExceptionHandler parent) { this.parent = parent; } @Override public ExceptionHandler getWrapped() { return this.parent; } @Override public void handle() throws FacesException { for (Iterator<ExceptionQueuedEvent> i = getUnhandledExceptionQueuedEvents().iterator(); i.hasNext();) { ExceptionQueuedEvent event = i.next(); System.out.println("Iterating over ExceptionQueuedEvents. Current:" + event.toString()); ExceptionQueuedEventContext context = (ExceptionQueuedEventContext) event.getSource(); Throwable t = context.getException(); if (t instanceof ViewExpiredException) { ViewExpiredException vee = (ViewExpiredException) t; FacesContext fc = FacesContext.getCurrentInstance(); NavigationHandler nav = fc.getApplication().getNavigationHandler(); try { // Push some useful stuff to the flash scope for // use in the page fc.getExternalContext().getFlash().put("expiredViewId", vee.getViewId()); nav.handleNavigation(fc, null, "/login?faces-redirect=true"); fc.renderResponse(); } finally { i.remove(); } } } // At this point, the queue will not contain any ViewExpiredEvents. // Therefore, let the parent handle them. getWrapped().handle(); } } But STILL i'm NOT redirected to my error page - i'm getting the same HTTP 500 error like above. What am i doing wrong, what could be missing in my implementation so that the exception is handled correctly?

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• Dynamically sized UIWebView in a UITableViewCell with auto layout - constraint violation

  - by Orion Edwards

  I've got a UITableViewCell which contains a UIWebView. The table view cell adjusts it's height depending on the web view contents. I've got it all working fine, however when the view loads, I get a constraint violation exception in the debugger (the app continues running and functionally works fine, but I'd like to resolve this exception if possible). How I've got it set up: The TableView sets the cell height like this: -(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath { if(indexPath.section == 0) { [_topCell layoutIfNeeded]; CGFloat finalHeight = [_topCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height; return finalHeight + 1; } The cell constraints are as follows: Arbitrary 7px offset from the cell's contentView (top) to the webView Web view has arbitrary fixed height constraint of 62px (will expand later once content loads) Arbitrary 8px offset from the webView to the cell's contentView (bottom) in my viewDidLoad, I tell the webView to go and load a URL, and in the webViewDidFinishLoad, I update the web view height constraint, like this -(void)webViewDidFinishLoad:(UIWebView *)webView { CGSize fittingSize = [webView sizeThatFits:CGSizeZero]; // fittingSize is approx 500 [self.tableView beginUpdates]; // Exceptions happen on the following line setting the constant _topCell.webViewHeightConstraint.constant = fittingSize.height; [_topCell layoutSubviews]; [self.tableView endUpdates]; } The exception looks like this: Unable to simultaneously satisfy constraints. Probably at least one of the constraints in the following list is one you don't want. Try this: (1) look at each constraint and try to figure out which you don't expect; (2) find the code that added the unwanted constraint or constraints and fix it. (Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) ( "<NSLayoutConstraint:0x10964b250 V:[webView(62)] (Names: webView:0x109664a00 )>", "<NSLayoutConstraint:0x109243d30 V:|-(7)-[webView] (Names: webView:0x109664a00, cellContent:0x1092436f0, '|':cellContent:0x1092436f0 )>", "<NSLayoutConstraint:0x109243f80 V:[webView]-(8)-| (Names: cellContent:0x1092436f0, webView:0x109664a00, '|':cellContent:0x1092436f0 )>", "<NSAutoresizingMaskLayoutConstraint:0x10967c210 h=--& v=--& V:[cellContent(78)] (Names: cellContent:0x1092436f0 )>" ) Will attempt to recover by breaking constraint <NSLayoutConstraint:0x10964b250 V:[webView(62)] (Names: webView:0x109664a00 )> This seems a bit weird. It's implied that the constraint which sets the height of the web view is going to be broken, however the web view does get it's height correctly set, and the tableview renders perfectly well. From my guesses, it looks like the newly increased web view height constraint (it's about 500px after the web view loads) is going to conflict with the <NSAutoresizingMaskLayoutConstraint:0x10967c210 h=--& v=--& V:[cellContent(78)] setting the cell height to 78 (put there by interface builder). This makes sense, however I don't want that cell content to have a fixed height of 78px, I want it to increase it's height, and functionally, it actually does this, just with these exceptions. I've tried setting _topCell.contentView.translatesAutoresizingMaskIntoConstraints = NO; to attempt to remove the NSAutoresizingMaskLayoutConstraint - this stops the exceptions, but then all the other layout is screwed up and the web view is about 10px high in the middle of the table view for no reason. I've also tried setting _topCell.contentView.autoresizingMask |= UIViewAutoresizingFlexibleHeight; in the viewDidLoad to hopefully affect the contentView 78px height constraint, but this has no effect Any help would be much appreciated

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• Isn't it better to use a single try catch instead of tons of TryParsing and other error handling sometimes?

  - by Ryan Peschel

  I know people say it's bad to use exceptions for flow control and to only use exceptions for exceptional situations, but sometimes isn't it just cleaner and more elegant to wrap the entire block in a try-catch? For example, let's say I have a dialog window with a TextBox where the user can type input in to be parsed in a key-value sort of manner. This situation is not as contrived as you might think because I've inherited code that has to handle this exact situation (albeit not with farm animals). Consider this wall of code: class Animals { public int catA, catB; public float dogA, dogB; public int mouseA, mouseB, mouseC; public double cow; } class Program { static void Main(string[] args) { string input = "Sets all the farm animals CAT 3 5 DOG 21.3 5.23 MOUSE 1 0 1 COW 12.25"; string[] splitInput = input.Split(' '); string[] animals = { "CAT", "DOG", "MOUSE", "COW", "CHICKEN", "GOOSE", "HEN", "BUNNY" }; Animals animal = new Animals(); for (int i = 0; i < splitInput.Length; i++) { string token = splitInput[i]; if (animals.Contains(token)) { switch (token) { case "CAT": animal.catA = int.Parse(splitInput[i + 1]); animal.catB = int.Parse(splitInput[i + 2]); break; case "DOG": animal.dogA = float.Parse(splitInput[i + 1]); animal.dogB = float.Parse(splitInput[i + 2]); break; case "MOUSE": animal.mouseA = int.Parse(splitInput[i + 1]); animal.mouseB = int.Parse(splitInput[i + 2]); animal.mouseC = int.Parse(splitInput[i + 3]); break; case "COW": animal.cow = double.Parse(splitInput[i + 1]); break; } } } } } In actuality there are a lot more farm animals and more handling than that. A lot of things can go wrong though. The user could enter in the wrong number of parameters. The user can enter the input in an incorrect format. The user could specify numbers too large or too small for the data type to handle. All these different errors could be handled without exceptions through the use of TryParse, checking how many parameters the user tried to use for a specific animal, checking if the parameter is too large or too small for the data type (because TryParse just returns 0), but every one should result in the same thing: A MessageBox appearing telling the user that the inputted data is invalid and to fix it. My boss doesn't want different message boxes for different errors. So instead of doing all that, why not just wrap the block in a try-catch and in the catch statement just display that error message box and let the user try again? Maybe this isn't the best example but think of any other scenario where there would otherwise be tons of error handling that could be substituted for a single try-catch. Is that not the better solution?

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• Self-updating collection concurrency issues

  - by DEHAAS

  I am trying to build a self-updating collection. Each item in the collection has a position (x,y). When the position is changed, an event is fired, and the collection will relocate the item. Internally the collection is using a “jagged dictionary”. The outer dictionary uses the x-coordinate a key, while the nested dictionary uses the y-coordinate a key. The nested dictionary then has a list of items as value. The collection also maintains a dictionary to store the items position as stored in the nested dictionaries – item to stored location lookup. I am having some trouble making the collection thread safe, which I really need. Source code for the collection: public class PositionCollection<TItem, TCoordinate> : ICollection<TItem> where TItem : IPositionable<TCoordinate> where TCoordinate : struct, IConvertible { private readonly object itemsLock = new object(); private readonly Dictionary<TCoordinate, Dictionary<TCoordinate, List<TItem>>> items; private readonly Dictionary<TItem, Vector<TCoordinate>> storedPositionLookup; public PositionCollection() { this.items = new Dictionary<TCoordinate, Dictionary<TCoordinate, List<TItem>>>(); this.storedPositionLookup = new Dictionary<TItem, Vector<TCoordinate>>(); } public void Add(TItem item) { if (item.Position == null) { throw new ArgumentException("Item must have a valid position."); } lock (this.itemsLock) { if (!this.items.ContainsKey(item.Position.X)) { this.items.Add(item.Position.X, new Dictionary<TCoordinate, List<TItem>>()); } Dictionary<TCoordinate, List<TItem>> xRow = this.items[item.Position.X]; if (!xRow.ContainsKey(item.Position.Y)) { xRow.Add(item.Position.Y, new List<TItem>()); } xRow[item.Position.Y].Add(item); if (this.storedPositionLookup.ContainsKey(item)) { this.storedPositionLookup[item] = new Vector<TCoordinate>(item.Position); } else { this.storedPositionLookup.Add(item, new Vector<TCoordinate>(item.Position)); // Store a copy of the original position } item.Position.PropertyChanged += (object sender, PropertyChangedEventArgs eventArgs) => this.UpdatePosition(item, eventArgs.PropertyName); } } private void UpdatePosition(TItem item, string propertyName) { lock (this.itemsLock) { Vector<TCoordinate> storedPosition = this.storedPositionLookup[item]; this.RemoveAt(storedPosition, item); this.storedPositionLookup.Remove(item); } } } I have written a simple unit test to check for concurrency issues: [TestMethod] public void TestThreadedPositionChange() { PositionCollection<Crate, int> collection = new PositionCollection<Crate, int>(); Crate crate = new Crate(new Vector<int>(5, 5)); collection.Add(crate); Parallel.For(0, 100, new Action<int>((i) => crate.Position.X += 1)); Crate same = collection[105, 5].First(); Assert.AreEqual(crate, same); } The actual stored position varies every time I run the test. I appreciate any feedback you may have.

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• Parallelism in .NET – Part 19, TaskContinuationOptions

  - by Reed

  My introduction to Task continuations demonstrates continuations on the Task class.  In addition, I’ve shown how continuations allow handling of multiple tasks in a clean, concise manner.  Continuations can also be used to handle exceptional situations using a clean, simple syntax. In addition to standard Task continuations , the Task class provides some options for filtering continuations automatically.  This is handled via the TaskContinationOptions enumeration, which provides hints to the TaskScheduler that it should only continue based on the operation of the antecedent task. This is especially useful when dealing with exceptions.  For example, we can extend the sample from our earlier continuation discussion to include support for handling exceptions thrown by the Factorize method: // Get a copy of the UI-thread task scheduler up front to use later var uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); // Start our task var factorize = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); // When we succeed, report the results to the UI factorize.ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), CancellationToken.None, TaskContinuationOptions.NotOnFaulted, uiScheduler); // When we have an exception, report it factorize.ContinueWith(task => textBox1.Text = string.Format("Error: {0}", task.Exception.Message), CancellationToken.None, TaskContinuationOptions.OnlyOnFaulted, uiScheduler); .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; } The above code works by using a combination of features.  First, we schedule our task, the same way as in the previous example.  However, in this case, we use a different overload of Task.ContinueWith which allows us to specify both a specific TaskScheduler (in order to have your continuation run on the UI’s synchronization context) as well as a TaskContinuationOption.  In the first continuation, we tell the continuation that we only want it to run when there was not an exception by specifying TaskContinuationOptions.NotOnFaulted.  When our factorize task completes successfully, this continuation will automatically run on the UI thread, and provide the appropriate feedback. However, if the factorize task has an exception – for example, if the Factorize method throws an exception due to an improper input value, the second continuation will run.  This occurs due to the specification of TaskContinuationOptions.OnlyOnFaulted in the options.  In this case, we’ll report the error received to the user. We can use TaskContinuationOptions to filter our continuations by whether or not an exception occurred and whether or not a task was cancelled.  This allows us to handle many situations, and is especially useful when trying to maintain a valid application state without ever blocking the user interface.  The same concepts can be extended even further, and allow you to chain together many tasks based on the success of the previous ones.  Continuations can even be used to create a state machine with full error handling, all without blocking the user interface thread.

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• Error Handling Examples(C#)

  “The purpose of reviewing the Error Handling code is to assure that the application fails safely under all possible error conditions, expected and unexpected. No sensitive information is presented to the user when an error occurs.” (OWASP, 2011) No Error Handling The absence of error handling is still a form of error handling. Based on the code in Figure 1, if an error occurred and was not handled within either the ReadXml or BuildRequest methods the error would bubble up to the Search method. Since this method does not handle any acceptations the error will then bubble up the stack trace. If this continues and the error is not handled within the application then the environment in which the application is running will notify the user running the application that an error occurred based on what type of application. Figure 1: No Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); dt.ReadXml(BuildRequest(searchTerm, resultCount)); return dt; } Generic Error Handling One simple way to add error handling is to catch all errors by default. If you examine the code in Figure 2, you will see a try-catch block. On April 6th 2010 Louis Lazaris clearly describes a Try Catch statement by defining both the Try and Catch aspects of the statement. “The try portion is where you would put any code that might throw an error. In other words, all significant code should go in the try section. The catch section will also hold code, but that section is not vital to the running of the application. So, if you removed the try-catch statement altogether, the section of code inside the try part would still be the same, but all the code inside the catch would be removed.” (Lazaris, 2010) He also states that all errors that occur in the try section cause it to stops the execution of the try section and redirects all execution to the catch section. The catch section receives an object containing information about the error that occurred so that they system can gracefully handle the error properly. When errors occur they commonly log them in some form. This form could be an email, database entry, web service call, log file, or just an error massage displayed to the user.  Depending on the error sometimes applications can recover, while others force an application to close. Figure 2: Generic Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); try { dt.ReadXml(BuildRequest(searchTerm, resultCount)); } catch (Exception ex) { // Handle all Exceptions } return dt; } Error Specific Error Handling Like the Generic Error Handling, Error Specific error handling allows for the catching of specific known errors that may occur. For example wrapping a try catch statement around a soap web service call would allow the application to handle any error that was generated by the soap web service. Now, if the systems wanted to send a message to the web service provider every time a soap error occurred but did not want to notify them if any other type of error occurred like a network time out issue. This would be varying tedious to accomplish using the General Error Handling methodology. This brings us to the use case for using the Error Specific error handling methodology.  The Error Specific Error handling methodology allows for the TryCatch statement to catch various types of errors depending on the type of error that occurred. In Figure 3, the code attempts to handle DataException differently compared to how it potentially handles all other errors. This allows for specific error handling for each type of known error, and still allows for error handling of any unknown error that my occur during the execution of the TryCatch statement. Figure 5: Error Specific Error Handling public DataSet Search(string searchTerm, int resultCount) { DataSet dt = new DataSet(); try { dt.ReadXml(BuildRequest(searchTerm, resultCount)); } catch (TimeoutException ex) { // Handle Timeout TimeoutException Only } catch (Exception) { // Handle all Exceptions } return dt; }

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• Tuple in C# 4.0

  - by Jalpesh P. Vadgama

  C# 4.0 language includes a new feature called Tuple. Tuple provides us a way of grouping elements of different data type. That enables us to use it a lots places at practical world like we can store a coordinates of graphs etc. In C# 4.0 we can create Tuple with Create method. This Create method offer 8 overload like following. So you can group maximum 8 data types with a Tuple. Followings are overloads of a data type. Create(T1)- Which represents a tuple of size 1 Create(T1,T2)- Which represents a tuple of size 2 Create(T1,T2,T3) – Which represents a tuple of size 3 Create(T1,T2,T3,T4) – Which represents a tuple of size 4 Create(T1,T2,T3,T4,T5) – Which represents a tuple of size 5 Create(T1,T2,T3,T4,T5,T6) – Which represents a tuple of size 6 Create(T1,T2,T3,T4,T5,T6,T7) – Which represents a tuple of size 7 Create(T1,T2,T3,T4,T5,T6,T7,T8) – Which represents a tuple of size 8 Following are some example code for tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple); var t = System.Tuple.Create<int, string>(1, "Jalpesh"); Console.WriteLine(t); } } } Following is a output of above as expected. You can also access values insides Tuple with ItemN property. Where N represents particular number of item in tuple. Following is an example of it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create<string, string, string>("Jalpesh", "P", "Vadgama"); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Here you can see I have printed items with Item1,Item2 and Item3 . Following is the output of above code.   Even we can create a nested tuple also following is code for nested tuple. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace TupleExample { class Program { static void Main(string[] args) { var tuple = System.Tuple.Create(1,"Jalpesh",new Tuple<string,string>("P","Vadgama")); Console.WriteLine(tuple.Item1); Console.WriteLine(tuple.Item2); Console.WriteLine(tuple.Item3); } } } Following is a output above code as expected. As you can see there are unlimited possibilities we can do lots of things with Tuple. Hope you liked it. Stay tuned for more. Till then Happy Programming!!

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• career in Mobile sw/Application Development [closed]

  - by pramod

  i m planning to do a course on Wireless & mobile computing.The syllabus are given below.Please check & let me know whether its worth to do.How is the job prospects after that.I m a fresher & from electronic Engg.The modules are- *Wireless and Mobile Computing (WiMC) – Modules* C, C++ Programming and Data Structures 100 Hours C Revision C, C++ programming tools on linux(Vi editor, gdb etc.) OOP concepts Programming constructs Functions Access Specifiers Classes and Objects Overloading Inheritance Polymorphism Templates Data Structures in C++ Arrays, stacks, Queues, Linked Lists( Singly, Doubly, Circular) Trees, Threaded trees, AVL Trees Graphs, Sorting (bubble, Quick, Heap , Merge) System Development Methodology 18 Hours Software life cycle and various life cycle models Project Management Software: A Process Various Phases in s/w Development Risk Analysis and Management Software Quality Assurance Introduction to Coding Standards Software Project Management Testing Strategies and Tactics Project Management and Introduction to Risk Management Java Programming 110 Hours Data Types, Operators and Language Constructs Classes and Objects, Inner Classes and Inheritance Inheritance Interface and Package Exceptions Threads Java.lang Java.util Java.awt Java.io Java.applet Java.swing XML, XSL, DTD Java n/w programming Introduction to servlet Mobile and Wireless Technologies 30 Hours Basics of Wireless Technologies Cellular Communication: Single cell systems, multi-cell systems, frequency reuse, analog cellular systems, digital cellular systems GSM standard: Mobile Station, BTS, BSC, MSC, SMS sever, call processing and protocols CDMA standard: spread spectrum technologies, 2.5G and 3G Systems: HSCSD, GPRS, W-CDMA/UMTS,3GPP and international roaming, Multimedia services CDMA based cellular mobile communication systems Wireless Personal Area Networks: Bluetooth, IEEE 802.11a/b/g standards Mobile Handset Device Interfacing: Data Cables, IrDA, Bluetooth, Touch- Screen Interfacing Wireless Security, Telemetry Java Wireless Programming and Applications Development(J2ME) 100 Hours J2ME Architecture The CLDC and the KVM Tools and Development Process Classification of CLDC Target Devices CLDC Collections API CLDC Streams Model MIDlets MIDlet Lifecycle MIDP Programming MIDP Event Architecture High-Level Event Handling Low-Level Event Handling The CLDC Streams Model The CLDC Networking Package The MIDP Implementation Introduction to WAP, WML Script and XHTML Introduction to Multimedia Messaging Services (MMS) Symbian Programming 60 Hours Symbian OS basics Symbian OS services Symbian OS organization GUI approaches ROM building Debugging Hardware abstraction Base porting Symbian OS reference design porting File systems Overview of Symbian OS Development – DevKits, CustKits and SDKs CodeWarrior Tool Application & UI Development Client Server Framework ECOM STDLIB in Symbian iPhone Programming 80 Hours Introducing iPhone core specifications Understanding iPhone input and output Designing web pages for the iPhone Capturing iPhone events Introducing the webkit CSS transforms transitions and animations Using iUI for web apps Using Canvas for web apps Building web apps with Dashcode Writing Dashcode programs Debugging iPhone web pages SDK programming for web developers An introduction to object-oriented programming Introducing the iPhone OS Using Xcode and Interface builder Programming with the SDK Toolkit OS Concepts & Linux Programming 60 Hours Operating System Concepts What is an OS? Processes Scheduling & Synchronization Memory management Virtual Memory and Paging Linux Architecture Programming in Linux Linux Shell Programming Writing Device Drivers Configuring and Building GNU Cross-tool chain Configuring and Compiling Linux Virtual File System Porting Linux on Target Hardware WinCE.NET and Database Technology 80 Hours Execution Process in .NET Environment Language Interoperability Assemblies Need of C# Operators Namespaces & Assemblies Arrays Preprocessors Delegates and Events Boxing and Unboxing Regular Expression Collections Multithreading Programming Memory Management Exceptions Handling Win Forms Working with database ASP .NET Server Controls and client-side scripts ASP .NET Web Server Controls Validation Controls Principles of database management Need of RDBMS etc Client/Server Computing RDBMS Technologies Codd’s Rules Data Models Normalization Techniques ER Diagrams Data Flow Diagrams Database recovery & backup SQL Android Application 80 Hours Introduction of android Why develop for android Android SDK features Creating android activities Fundamental android UI design Intents, adapters, dialogs Android Technique for saving data Data base in Androids Maps, Geocoding, Location based services Toast, using alarms, Instant messaging Using blue tooth Using Telephony Introducing sensor manager Managing network and wi-fi connection Advanced androids development Linux kernel security Implement AIDL Interface. Project 120 Hours

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• Flow-Design Cheat Sheet &ndash; Part II, Translation

  - by Ralf Westphal

  In my previous post I summarized the notation for Flow-Design (FD) diagrams. Now is the time to show you how to translate those diagrams into code. Hopefully you feel how different this is from UML. UML leaves you alone with your sequence diagram or component diagram or activity diagram. They leave it to you how to translate your elaborate design into code. Or maybe UML thinks it´s so easy no further explanations are needed? I don´t know. I just know that, as soon as people stop designing with UML and start coding, things end up to be very different from the design. And that´s bad. That degrades graphical designs to just time waste on paper (or some designer). I even believe that´s the reason why most programmers view textual source code as the only and single source of truth. Design and code usually do not match. FD is trying to change that. It wants to make true design a first class method in every developers toolchest. For that the first prerequisite is to be able to easily translate any design into code. Mechanically, without thinking. Even a compiler could do it :-) (More of that in some other article.) Translating to Methods The first translation I want to show you is for small designs. When you start using FD you should translate your diagrams like this. Functional units become methods. That´s it. An input-pin becomes a method parameter, an output-pin becomes a return value: The above is a part. But a board can be translated likewise and calls the nested FUs in order: In any case be sure to keep the board method clear of any and all business logic. It should not contain any control structures like if, switch, or a loop. Boards do just one thing: calling nested functional units in proper sequence. What about multiple input-pins? Try to avoid them. Replace them with a join returning a tuple: What about multiple output-pins? Try to avoid them. Or return a tuple. Or use out-parameters: But as I said, this simple translation is for simple designs only. Splits and joins are easily done with method translation: All pretty straightforward, isn´t it. But what about wires, named pins, entry points, explicit dependencies? I suggest you don´t use this kind of translation when your designs need these features. Translating to methods is for small scale designs like you might do once you´re working on the implementation of a part of a larger design. Or maybe for a code kata you´re doing in your local coding dojo. Instead of doing TDD try doing FD and translate your design into methods. You´ll see that way it´s much easier to work collaboratively on designs, remember them more easily, keep them clean, and lessen the need for refactoring. Translating to Events [coming soon]

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• How to Open Any Folder as a Project in the NetBeans Platform

  - by Geertjan

  Typically, as described in the NetBeans Project Type Tutorial, you'll define a project type based on the presence of a file (e.g., "project.xml" or "customer.txt" or something like that) in a folder. I.e., if the file is there, then its parent, i.e., the folder that contains the file, is a project and should be opened in your application. However, in some scenarios (as with the HTML5 project type introduced in NetBeans IDE 7.3), the user should be able to open absolutely any folder at all into the application. How to create a project type that is that liberal? Here you go, the only condition that needs to be true is that the selected item in the "Open Project" dialog is a folder, as defined in the "isProject" method below. Nothing else. That's it. If you select a folder, it will be opened in your application, displaying absolutely everything as-is (since below there's no ProjectLogicalView defined): import java.beans.PropertyChangeListener; import java.io.IOException; import javax.swing.Icon; import org.netbeans.api.project.Project; import org.netbeans.api.project.ProjectInformation; import org.netbeans.spi.project.ProjectFactory; import org.netbeans.spi.project.ProjectState; import org.openide.filesystems.FileObject; import org.openide.loaders.DataFolder; import org.openide.loaders.DataObjectNotFoundException; import org.openide.nodes.FilterNode; import org.openide.util.Exceptions; import org.openide.util.ImageUtilities; import org.openide.util.Lookup; import org.openide.util.lookup.Lookups; import org.openide.util.lookup.ServiceProvider; @ServiceProvider(service = ProjectFactory.class) public class FolderProjectFactory implements ProjectFactory { @Override public boolean isProject(FileObject projectDirectory) { return DataFolder.findFolder(projectDirectory) != null; } @Override public Project loadProject(FileObject dir, ProjectState state) throws IOException { return isProject(dir) ? new FolderProject(dir) : null; } @Override public void saveProject(Project prjct) throws IOException, ClassCastException { // leave unimplemented for the moment } private class FolderProject implements Project { private final FileObject projectDir; private Lookup lkp; private FolderProject(FileObject dir) { this.projectDir = dir; } @Override public FileObject getProjectDirectory() { return projectDir; } @Override public Lookup getLookup() { if (lkp == null) { lkp = Lookups.fixed(new Object[]{ new Info(), }); } return lkp; } private final class Info implements ProjectInformation { @Override public Icon getIcon() { Icon icon = null; try { icon = ImageUtilities.image2Icon( new FilterNode(DataFolder.find( getProjectDirectory()).getNodeDelegate()).getIcon(1)); } catch (DataObjectNotFoundException ex) { Exceptions.printStackTrace(ex); } return icon; } @Override public String getName() { return getProjectDirectory().getName(); } @Override public String getDisplayName() { return getName(); } @Override public void addPropertyChangeListener(PropertyChangeListener pcl) { //do nothing, won't change } @Override public void removePropertyChangeListener(PropertyChangeListener pcl) { //do nothing, won't change } @Override public Project getProject() { return FolderProject.this; } } } } Even the ProjectInformation implementation really isn't needed at all, since it provides nothing more than the icon in the "Open Project" dialog, the rest (i.e., the display name in the "Open Project" dialog) is provided by default regardless of whether you have a ProjectInformation implementation or not.

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• Oracle GoldenGate Active-Active Part 1

  - by Nick_W

  My name is Nick Wagner, and I'm a recent addition to the Oracle Maximum Availability Architecture (MAA) product management team.  I've spent the last 15+ years working on database replication products, and I've spent the last 10 years working on the Oracle GoldenGate product.  So most of my posting will probably be focused on OGG.  One question that comes up all the time is around active-active replication with Oracle GoldenGate.  How do I know if my application is a good fit for active-active replication with GoldenGate?   To answer that, it really comes down to how you plan on handling conflict resolution.  I will delve into topology and deployment in a later blog, but here is a simple architecture: The two most common resolution routines are host based resolution and timestamp based resolution. Host based resolution is used less often, but works with the fewest application changes.  Think of it like this: any transactions from SystemA always take precedence over any transactions from SystemB.  If there is a conflict on SystemB, then the record from SystemA will overwrite it.  If there is a conflict on SystemA, then it will be ignored.  It is quite a bit less restrictive, and in most cases, as long as all the tables have primary keys, host based resolution will work just fine.  Timestamp based resolution, on the other hand, is a little trickier. In this case, you can decide which record is overwritten based on timestamps. For example, does the older record get overwritten with the newer record?  Or vice-versa?  This method not only requires primary keys on every table, but it also requires every table to have a timestamp/date column that is updated each time a record is inserted or updated on the table.  Most homegrown applications can always be customized to include these requirements, but it's a little more difficult with 3rd party applications, and might even be impossible for large ERP type applications.  If your database has these features - whether it’s primary keys for host based resolution, or primary keys and timestamp columns for timestamp based resolution - then your application could be a great candidate for active-active replication.  But table structure is not the only requirement.  The other consideration applies when there is a conflict; i.e., do I need to perform any notification or track down the user that had their data overwritten?  In most cases, I don't think it's necessary, but if it is required, OGG can always create an exceptions table that contains all of the overwritten transactions so that people can be notified. It's a bit of extra work to implement this type of option, but if the business requires it, then it can be done. Unless someone is constantly monitoring this exception table or has an automated process in dealing with exceptions, there will be a delay in getting a response back to the end user. Ideally, when setting up active-active resolution we can include some simple procedural steps or configuration options that can reduce, or in some cases eliminate the potential for conflicts.  This makes the whole implementation that much easier and foolproof.  And I'll cover these in my next blog. 

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• Activation Error while testing Exception Handling Application Block

  - by CletusLoomis

  I'm getting the following error while testing my EHAB implementation: {"Activation error occured while trying to get instance of type ExceptionPolicyImpl, key "LogPolicy""} System.Exception Stack Trace: StackTrace " at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance(Type serviceType, String key) in c:\Home\Chris\Projects\CommonServiceLocator\main\Microsoft.Practices.ServiceLocation\ServiceLocatorImplBase.cs:line 53 at Microsoft.Practices.ServiceLocation.ServiceLocatorImplBase.GetInstance[TService](String key) in c:\Home\Chris\Projects\CommonServiceLocator\main\Microsoft.Practices.ServiceLocation\ServiceLocatorImplBase.cs:line 103 at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.GetExceptionPolicy(Exception exception, String policyName) in e:\Builds\EntLib\Latest\Source\Blocks\ExceptionHandling\Src\ExceptionHandling\ExceptionPolicy.cs:line 131 at Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException(Exception exceptionToHandle, String policyName) in e:\Builds\EntLib\Latest\Source\Blocks\ExceptionHandling\Src\ExceptionHandling\ExceptionPolicy.cs:line 55 at Blackbox.Exception.ExceptionMain.LogException(Exception pException) in C:_Work_Black Box\Blackbox.Exception\ExceptionMain.vb:line 14 at BlackBox.Business.BusinessMain.TestExceptionHandling() in C:_Work_Black Box\BlackBox.Business\BusinessMain.vb:line 16 at Blackbox.Service.Service1.TestExceptionHandling() in C:_Work_Black Box\Blackbox.Service\Service.svc.vb:line 43" String Inner Exception: InnerException {"Resolution of the dependency failed, type = "Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl", name = "LogPolicy". Exception occurred while: Calling constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener(System.String source, System.String log, System.String machineName, Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.ILogFormatter formatter). Exception is: ArgumentException - Event log names must consist of printable characters and cannot contain \, *, ?, or spaces At the time of the exception, the container was: Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl,LogPolicy Resolving parameter "policyEntries" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyImpl(System.String policyName, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] policyEntries) Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry,LogPolicy.All Exceptions Resolving parameter "handlers" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicyEntry(System.Type exceptionType, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.PostHandlingAction postHandlingAction, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.IExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] handlers, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Instrumentation.IExceptionHandlingInstrumentationProvider instrumentationProvider) Resolving Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler,LogPolicy.All Exceptions.Logging Exception Handler (mapped from Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.IExceptionHandler, LogPolicy.All Exceptions.Logging Exception Handler) Resolving parameter "writer" of constructor Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler(System.String logCategory, System.Int32 eventId, System.Diagnostics.TraceEventType severity, System.String title, System.Int32 priority, System.Type formatterType, Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter writer) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterImpl,LogWriter.default (mapped from Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter, (none)) Resolving parameter "structureHolder" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterImpl(Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder structureHolder, Microsoft.Practices.EnterpriseLibrary.Logging.Instrumentation.ILoggingInstrumentationProvider instrumentationProvider, Microsoft.Practices.EnterpriseLibrary.Logging.ILoggingUpdateCoordinator updateCoordinator) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder,LogWriterStructureHolder.default (mapped from Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder, (none)) Resolving parameter "traceSources" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogWriterStructureHolder(System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.Logging.Filters.ILogFilter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] filters, System.Collections.Generic.IEnumerable1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] traceSourceNames, System.Collections.Generic.IEnumerable1[[Microsoft.Practices.EnterpriseLibrary.Logging.LogSource, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]] traceSources, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource allEventsTraceSource, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource notProcessedTraceSource, Microsoft.Practices.EnterpriseLibrary.Logging.LogSource errorsTraceSource, System.String defaultCategory, System.Boolean tracingEnabled, System.Boolean logWarningsWhenNoCategoriesMatch, System.Boolean revertImpersonation) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogSource,General Resolving parameter "traceListeners" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.LogSource(System.String name, System.Collections.Generic.IEnumerable1[[System.Diagnostics.TraceListener, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] traceListeners, System.Diagnostics.SourceLevels level, System.Boolean autoFlush, Microsoft.Practices.EnterpriseLibrary.Logging.Instrumentation.ILoggingInstrumentationProvider instrumentationProvider) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.ReconfigurableTraceListenerWrapper,Event Log Listener (mapped from System.Diagnostics.TraceListener, Event Log Listener) Resolving parameter "wrappedTraceListener" of constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.ReconfigurableTraceListenerWrapper(System.Diagnostics.TraceListener wrappedTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging.ILoggingUpdateCoordinator coordinator) Resolving Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener,Event Log Listener?implementation (mapped from System.Diagnostics.TraceListener, Event Log Listener?implementation) Calling constructor Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener(System.String source, System.String log, System.String machineName, Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.ILogFormatter formatter) "} System.Exception My web.config is as follows: <?xml version="1.0"?> <configuration> <configSections> <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> <section name="exceptionHandling" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Configuration.ExceptionHandlingSettings, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" /> </configSections> <loggingConfiguration name="" tracingEnabled="true" defaultCategory="General"> <listeners> <add name="Event Log Listener" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FormattedEventLogTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" source="Enterprise Library Logging" formatter="Text Formatter" log="C:\Blackbox.log" machineName="." traceOutputOptions="LogicalOperationStack, DateTime, Timestamp, Callstack" /> </listeners> <formatters> <add type="Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.TextFormatter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" template="Timestamp: {timestamp}{newline}&#xA;Message: {message}{newline}&#xA;Category: {category}{newline}&#xA;Priority: {priority}{newline}&#xA;EventId: {eventid}{newline}&#xA;Severity: {severity}{newline}&#xA;Title:{title}{newline}&#xA;Machine: {localMachine}{newline}&#xA;App Domain: {localAppDomain}{newline}&#xA;ProcessId: {localProcessId}{newline}&#xA;Process Name: {localProcessName}{newline}&#xA;Thread Name: {threadName}{newline}&#xA;Win32 ThreadId:{win32ThreadId}{newline}&#xA;Extended Properties: {dictionary({key} - {value}{newline})}" name="Text Formatter" /> </formatters> <categorySources> <add switchValue="All" name="General"> <listeners> <add name="Event Log Listener" /> </listeners> </add> </categorySources> <specialSources> <allEvents switchValue="All" name="All Events" /> <notProcessed switchValue="All" name="Unprocessed Category" /> <errors switchValue="All" name="Logging Errors &amp; Warnings"> <listeners> <add name="Event Log Listener" /> </listeners> </errors> </specialSources> </loggingConfiguration> <exceptionHandling> <exceptionPolicies> <add name="LogPolicy"> <exceptionTypes> <add name="All Exceptions" type="System.Exception, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="NotifyRethrow"> <exceptionHandlers> <add name="Logging Exception Handler" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging.LoggingExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" logCategory="General" eventId="100" severity="Error" title="Enterprise Library Exception Handling" formatterType="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.TextExceptionFormatter, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling" priority="0" /> </exceptionHandlers> </add> </exceptionTypes> </add> <add name="WcfExceptionShielding"> <exceptionTypes> <add name="InvalidOperationException" type="System.InvalidOperationException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" postHandlingAction="ThrowNewException"> <exceptionHandlers> <add type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.WCF.FaultContractExceptionHandler, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.WCF, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" exceptionMessageResourceType="" exceptionMessageResourceName="This is the message" exceptionMessage="This is the exception" faultContractType="Blackbox.Service.WCFFault, Blackbox.Service, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" name="Fault Contract Exception Handler"> <mappings> <add source="{Guid}" name="Id" /> <add source="{Message}" name="MessageText" /> </mappings> </add> </exceptionHandlers> </add> </exceptionTypes> </add> </exceptionPolicies> </exceptionHandling> <connectionStrings> <add name="CompassEntities" connectionString="metadata=~\bin\CompassModel.csdl|~\bin\CompassModel.ssdl|~\bin\CompassModel.msl;provider=Devart.Data.Oracle;provider connection string=&quot;User Id=foo;Password=foo;Server=foo64mo;Home=OraClient11g_home1;Persist Security Info=True&quot;" providerName="System.Data.EntityClient" /> <add name="BlackboxEntities" connectionString="metadata=~\bin\BlackboxModel.csdl|~\bin\BlackboxModel.ssdl|~\bin\BlackboxModel.msl;provider=System.Data.SqlClient;provider connection string=&quot;Data Source=sqldev1\cps;Initial Catalog=FundServ;Integrated Security=True;MultipleActiveResultSets=True&quot;" providerName="System.Data.EntityClient" /> </connectionStrings> <system.web> <compilation debug="true" strict="false" explicit="true" targetFramework="4.0" /> </system.web> <system.serviceModel> <behaviors> <serviceBehaviors> <behavior> <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment --> <serviceMetadata httpGetEnabled="true"/> <!-- To receive exception details in faults for debugging purposes, set the value below to true. Set to false before deployment to avoid disclosing exception information --> <serviceDebug includeExceptionDetailInFaults="false"/> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment multipleSiteBindingsEnabled="true" /> </system.serviceModel> <system.webServer> <modules runAllManagedModulesForAllRequests="true"/> </system.webServer> </configuration> My code is as follows: Public Shared Function LogException(ByVal pException As System.Exception) As Boolean Return ExceptionPolicy.HandleException(pException, "LogPolicy") End Function Any assistance is appreciated.

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• Very slow performance deserializing using datacontractserializer in a Silverlight Application.

  - by caryden

  Here is the situation: Silverlight 3 Application hits an asp.net hosted WCF service to get a list of items to display in a grid. Once the list is brought down to the client it is cached in IsolatedStorage. This is done by using the DataContractSerializer to serialize all of these objects to a stream which is then zipped and then encrypted. When the application is relaunched, it first loads from the cache (reversing the process above) and the deserializes the objects using the DataContractSerializer.ReadObject() method. All of this was working wonderfully under all scenarios until recently with the entire "load from cache" path (decrypt/unzip/deserialize) taking hundreds of milliseconds at most. On some development machines but not all (all machines Windows 7) the deserialize process - that is the call to ReadObject(stream) takes several minutes an seems to lock up the entire machine BUT ONLY WHEN RUNNING IN THE DEBUGGER in VS2008. Running the Debug configuration code outside the debugger has no problem. One thing that seems to look suspicious is that when you turn on stop on Exceptions, you can see that the ReadObject() throws many, many System.FormatException's indicating that a number was not in the correct format. When I turn off "Just My Code" thousands of these get dumped to the screen. None go unhandled. These occur both on the read back from the cache AND on a deserialization at the conclusion of a web service call to get the data from the WCF Service. HOWEVER, these same exceptions occur on my laptop development machine that does not experience the slowness at all. And FWIW, my laptop is really old and my desktop is a 4 core, 6GB RAM beast. Again, no problems unless running under the debugger in VS2008. Anyone else seem this? Any thoughts? Here is the bug report link: https://connect.microsoft.com/VisualStudio/feedback/details/539609/very-slow-performance-deserializing-using-datacontractserializer-in-a-silverlight-application-only-in-debugger

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• Spring AOP AfterThrowing vs. Around Advice

  - by whiskerz

  Hey there, when trying to implement an Aspect, that is responsible for catching and logging a certain type of error, I initially thought this would be possible using the AfterThrowing advice. However it seems that his advice doesn't catch the exception, but just provides an additional entry point to do something with the exception. The only advice which would also catch the exception in question would then be an AroundAdvice - either that or I did something wrong. Can anyone assert that indeed if I want to catch the exception I have to use an AroundAdvice? The configuration I used follows: @Pointcut("execution(* test.simple.OtherService.print*(..))") public void printOperation() {} @AfterThrowing(pointcut="printOperation()", throwing="exception") public void logException(Throwable exception) { System.out.println(exception.getMessage()); } @Around("printOperation()") public void swallowException(ProceedingJoinPoint pjp) throws Throwable { try { pjp.proceed(); } catch (Throwable exception) { System.out.println(exception.getMessage()); } } Note that in this example I caught all Exceptions, because it just is an example. I know its bad practice to just swallow all exceptions, but for my current use case I want one special type of exception to be just logged while avoiding duplicate logging logic.

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• java.lang.ClassCastException: org.apache.xerces.jaxp.DocumentBuilderFactoryImpl while starting the w

  - by venkat

  Hi, As part of our application we are using apache's xerces jaxp parser. When we deploy the application on weblogic9.2, we are getting the following error. org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.apache.cxf.wsdl.WSDLManager' defined in class path resource [META-INF/cxf/cxf.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.apache.cxf.wsdl11.WSDLManagerImpl]: Constructor threw exception; nested exception is java.lang.ClassCastException: org.apache.xerces.jaxp.DocumentBuilderFactoryImpl As per our analysis, i)The weblogic is trying to to load its own DocumentBuilderFactoryImpl which is present in weblogic.jar instead of apache's xerces. We tried the following to force the weblogic to load DocumentBuilderFactoryImpl from xerces i)we have added the following tag into weblogic.xml true ii)we have put latest versions of xalan in jre/lib/endorced folder. this didnt resolve our problem. ii) we have added entries in weblogic-application.xml webapp.encoding.default UTF-8 javax.jws. org.apache.xerces. org.apache.xerces.jaxp.* ii)Added the following entry in weblogic-application.xml <parser-factory> <saxparser-factory>org.apache.xerces.jaxp.SAXParserFactoryImpl</saxparser-factory> <document-builder-factory>org.apache.xerces.jaxp.DocumentBuilderFactoryImpl </document-builder-factory> org.apache.xalan.processor.TransformerFactoryImpl iii)Added jaxp.properties to load DocumentBuilderFactoryImpl from xerces to the jre/lib and started the server.In this case, the weblogic didnt start. iv)Then we started the server first and then copied the jaxp.properties file during the run time when server starts.But no success None of the above worked for us. Any help is highly appreciated. Thanks in advance, Venkat.

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• Creating a session scoped bean in Google App Engine using Spring 2.5

  - by zfranciscus

  Hi, I am trying to create a session bean in spring mvc. I am having the following error message when I run my google app engine server in my local box: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'siteController' defined in ServletContext resource [/WEB-INF/springapp-servlet.xml]: Cannot resolve reference to bean 'oAuth' while setting bean property 'oAuth'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'oAuth' defined in BeanDefinition defined in ServletContext resource [/WEB-INF/springapp-servlet.xml]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: **Cannot proxy target class because CGLIB2 is not available. Add CGLIB to the class path or specify proxy interfaces.** This is my spring mvc configuration: <bean name="oAuth" class="org.locate.server.FoursquareMgr" scope="session"> <aop:scoped-proxy/> </bean> <bean name="siteController" class="org.locate.server.SiteController" > <property name="oAuth" ref="oAuth"></property> </bean> I have enabled session in my google app engine appengine-web.xml file <sessions-enabled>true</sessions-enabled> I have included CGLIB2: cglib-2.1_3.jar and cglib-nodep-2.1_3.jar in my eclipse project build path. Has any one encountered this problem before ?

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• codingBat repeatEnd using regex

  - by polygenelubricants

  I'm trying to understand regex as much as I can, so I came up with this regex-based solution to codingbat.com repeatEnd: Given a string and an int N, return a string made of N repetitions of the last N characters of the string. You may assume that N is between 0 and the length of the string, inclusive. public String repeatEnd(String str, int N) { return str.replaceAll( ".(?!.{N})(?=.*(?<=(.{N})))|." .replace("N", Integer.toString(N)), "$1" ); } Explanation on its parts: .(?!.{N}): asserts that the matched character is one of the last N characters, by making sure that there aren't N characters following it. (?=.*(?<=(.{N}))): in which case, use lookforward to first go all the way to the end of the string, then a nested lookbehind to capture the last N characters into \1. Note that this assertion will always be true. |.: if the first assertion failed (i.e. there are at least N characters ahead) then match the character anyway; \1 would be empty. In either case, a character is always matched; replace it with \1. My questions are: Is this technique of nested assertions valid? (i.e. looking behind during a lookahead?) Is there a simpler regex-based solution?

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