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  • Informed TDD &ndash; Kata &ldquo;To Roman Numerals&rdquo;

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/05/28/informed-tdd-ndash-kata-ldquoto-roman-numeralsrdquo.aspxIn a comment on my article on what I call Informed TDD (ITDD) reader gustav asked how this approach would apply to the kata “To Roman Numerals”. And whether ITDD wasn´t a violation of TDD´s principle of leaving out “advanced topics like mocks”. I like to respond with this article to his questions. There´s more to say than fits into a commentary. Mocks and TDD I don´t see in how far TDD is avoiding or opposed to mocks. TDD and mocks are orthogonal. TDD is about pocess, mocks are about structure and costs. Maybe by moving forward in tiny red+green+refactor steps less need arises for mocks. But then… if the functionality you need to implement requires “expensive” resource access you can´t avoid using mocks. Because you don´t want to constantly run all your tests against the real resource. True, in ITDD mocks seem to be in almost inflationary use. That´s not what you usually see in TDD demonstrations. However, there´s a reason for that as I tried to explain. I don´t use mocks as proxies for “expensive” resource. Rather they are stand-ins for functionality not yet implemented. They allow me to get a test green on a high level of abstraction. That way I can move forward in a top-down fashion. But if you think of mocks as “advanced” or if you don´t want to use a tool like JustMock, then you don´t need to use mocks. You just need to stand the sight of red tests for a little longer ;-) Let me show you what I mean by that by doing a kata. ITDD for “To Roman Numerals” gustav asked for the kata “To Roman Numerals”. I won´t explain the requirements again. You can find descriptions and TDD demonstrations all over the internet, like this one from Corey Haines. Now here is, how I would do this kata differently. 1. Analyse A demonstration of TDD should never skip the analysis phase. It should be made explicit. The requirements should be formalized and acceptance test cases should be compiled. “Formalization” in this case to me means describing the API of the required functionality. “[D]esign a program to work with Roman numerals” like written in this “requirement document” is not enough to start software development. Coding should only begin, if the interface between the “system under development” and its context is clear. If this interface is not readily recognizable from the requirements, it has to be developed first. Exploration of interface alternatives might be in order. It might be necessary to show several interface mock-ups to the customer – even if that´s you fellow developer. Designing the interface is a task of it´s own. It should not be mixed with implementing the required functionality behind the interface. Unfortunately, though, this happens quite often in TDD demonstrations. TDD is used to explore the API and implement it at the same time. To me that´s a violation of the Single Responsibility Principle (SRP) which not only should hold for software functional units but also for tasks or activities. In the case of this kata the API fortunately is obvious. Just one function is needed: string ToRoman(int arabic). And it lives in a class ArabicRomanConversions. Now what about acceptance test cases? There are hardly any stated in the kata descriptions. Roman numerals are explained, but no specific test cases from the point of view of a customer. So I just “invent” some acceptance test cases by picking roman numerals from a wikipedia article. They are supposed to be just “typical examples” without special meaning. Given the acceptance test cases I then try to develop an understanding of the problem domain. I´ll spare you that. The domain is trivial and is explain in almost all kata descriptions. How roman numerals are built is not difficult to understand. What´s more difficult, though, might be to find an efficient solution to convert into them automatically. 2. Solve The usual TDD demonstration skips a solution finding phase. Like the interface exploration it´s mixed in with the implementation. But I don´t think this is how it should be done. I even think this is not how it really works for the people demonstrating TDD. They´re simplifying their true software development process because they want to show a streamlined TDD process. I doubt this is helping anybody. Before you code you better have a plan what to code. This does not mean you have to do “Big Design Up-Front”. It just means: Have a clear picture of the logical solution in your head before you start to build a physical solution (code). Evidently such a solution can only be as good as your understanding of the problem. If that´s limited your solution will be limited, too. Fortunately, in the case of this kata your understanding does not need to be limited. Thus the logical solution does not need to be limited or preliminary or tentative. That does not mean you need to know every line of code in advance. It just means you know the rough structure of your implementation beforehand. Because it should mirror the process described by the logical or conceptual solution. Here´s my solution approach: The arabic “encoding” of numbers represents them as an ordered set of powers of 10. Each digit is a factor to multiply a power of ten with. The “encoding” 123 is the short form for a set like this: {1*10^2, 2*10^1, 3*10^0}. And the number is the sum of the set members. The roman “encoding” is different. There is no base (like 10 for arabic numbers), there are just digits of different value, and they have to be written in descending order. The “encoding” XVI is short for [10, 5, 1]. And the number is still the sum of the members of this list. The roman “encoding” thus is simpler than the arabic. Each “digit” can be taken at face value. No multiplication with a base required. But what about IV which looks like a contradiction to the above rule? It is not – if you accept roman “digits” not to be limited to be single characters only. Usually I, V, X, L, C, D, M are viewed as “digits”, and IV, IX etc. are viewed as nuisances preventing a simple solution. All looks different, though, once IV, IX etc. are taken as “digits”. Then MCMLIV is just a sum: M+CM+L+IV which is 1000+900+50+4. Whereas before it would have been understood as M-C+M+L-I+V – which is more difficult because here some “digits” get subtracted. Here´s the list of roman “digits” with their values: {1, I}, {4, IV}, {5, V}, {9, IX}, {10, X}, {40, XL}, {50, L}, {90, XC}, {100, C}, {400, CD}, {500, D}, {900, CM}, {1000, M} Since I take IV, IX etc. as “digits” translating an arabic number becomes trivial. I just need to find the values of the roman “digits” making up the number, e.g. 1954 is made up of 1000, 900, 50, and 4. I call those “digits” factors. If I move from the highest factor (M=1000) to the lowest (I=1) then translation is a two phase process: Find all the factors Translate the factors found Compile the roman representation Translation is just a look-up. Finding, though, needs some calculation: Find the highest remaining factor fitting in the value Remember and subtract it from the value Repeat with remaining value and remaining factors Please note: This is just an algorithm. It´s not code, even though it might be close. Being so close to code in my solution approach is due to the triviality of the problem. In more realistic examples the conceptual solution would be on a higher level of abstraction. With this solution in hand I finally can do what TDD advocates: find and prioritize test cases. As I can see from the small process description above, there are two aspects to test: Test the translation Test the compilation Test finding the factors Testing the translation primarily means to check if the map of factors and digits is comprehensive. That´s simple, even though it might be tedious. Testing the compilation is trivial. Testing factor finding, though, is a tad more complicated. I can think of several steps: First check, if an arabic number equal to a factor is processed correctly (e.g. 1000=M). Then check if an arabic number consisting of two consecutive factors (e.g. 1900=[M,CM]) is processed correctly. Then check, if a number consisting of the same factor twice is processed correctly (e.g. 2000=[M,M]). Finally check, if an arabic number consisting of non-consecutive factors (e.g. 1400=[M,CD]) is processed correctly. I feel I can start an implementation now. If something becomes more complicated than expected I can slow down and repeat this process. 3. Implement First I write a test for the acceptance test cases. It´s red because there´s no implementation even of the API. That´s in conformance with “TDD lore”, I´d say: Next I implement the API: The acceptance test now is formally correct, but still red of course. This will not change even now that I zoom in. Because my goal is not to most quickly satisfy these tests, but to implement my solution in a stepwise manner. That I do by “faking” it: I just “assume” three functions to represent the transformation process of my solution: My hypothesis is that those three functions in conjunction produce correct results on the API-level. I just have to implement them correctly. That´s what I´m trying now – one by one. I start with a simple “detail function”: Translate(). And I start with all the test cases in the obvious equivalence partition: As you can see I dare to test a private method. Yes. That´s a white box test. But as you´ll see it won´t make my tests brittle. It serves a purpose right here and now: it lets me focus on getting one aspect of my solution right. Here´s the implementation to satisfy the test: It´s as simple as possible. Right how TDD wants me to do it: KISS. Now for the second equivalence partition: translating multiple factors. (It´a pattern: if you need to do something repeatedly separate the tests for doing it once and doing it multiple times.) In this partition I just need a single test case, I guess. Stepping up from a single translation to multiple translations is no rocket science: Usually I would have implemented the final code right away. Splitting it in two steps is just for “educational purposes” here. How small your implementation steps are is a matter of your programming competency. Some “see” the final code right away before their mental eye – others need to work their way towards it. Having two tests I find more important. Now for the next low hanging fruit: compilation. It´s even simpler than translation. A single test is enough, I guess. And normally I would not even have bothered to write that one, because the implementation is so simple. I don´t need to test .NET framework functionality. But again: if it serves the educational purpose… Finally the most complicated part of the solution: finding the factors. There are several equivalence partitions. But still I decide to write just a single test, since the structure of the test data is the same for all partitions: Again, I´m faking the implementation first: I focus on just the first test case. No looping yet. Faking lets me stay on a high level of abstraction. I can write down the implementation of the solution without bothering myself with details of how to actually accomplish the feat. That´s left for a drill down with a test of the fake function: There are two main equivalence partitions, I guess: either the first factor is appropriate or some next. The implementation seems easy. Both test cases are green. (Of course this only works on the premise that there´s always a matching factor. Which is the case since the smallest factor is 1.) And the first of the equivalence partitions on the higher level also is satisfied: Great, I can move on. Now for more than a single factor: Interestingly not just one test becomes green now, but all of them. Great! You might say, then I must have done not the simplest thing possible. And I would reply: I don´t care. I did the most obvious thing. But I also find this loop very simple. Even simpler than a recursion of which I had thought briefly during the problem solving phase. And by the way: Also the acceptance tests went green: Mission accomplished. At least functionality wise. Now I´ve to tidy up things a bit. TDD calls for refactoring. Not uch refactoring is needed, because I wrote the code in top-down fashion. I faked it until I made it. I endured red tests on higher levels while lower levels weren´t perfected yet. But this way I saved myself from refactoring tediousness. At the end, though, some refactoring is required. But maybe in a different way than you would expect. That´s why I rather call it “cleanup”. First I remove duplication. There are two places where factors are defined: in Translate() and in Find_factors(). So I factor the map out into a class constant. Which leads to a small conversion in Find_factors(): And now for the big cleanup: I remove all tests of private methods. They are scaffolding tests to me. They only have temporary value. They are brittle. Only acceptance tests need to remain. However, I carry over the single “digit” tests from Translate() to the acceptance test. I find them valuable to keep, since the other acceptance tests only exercise a subset of all roman “digits”. This then is my final test class: And this is the final production code: Test coverage as reported by NCrunch is 100%: Reflexion Is this the smallest possible code base for this kata? Sure not. You´ll find more concise solutions on the internet. But LOC are of relatively little concern – as long as I can understand the code quickly. So called “elegant” code, however, often is not easy to understand. The same goes for KISS code – especially if left unrefactored, as it is often the case. That´s why I progressed from requirements to final code the way I did. I first understood and solved the problem on a conceptual level. Then I implemented it top down according to my design. I also could have implemented it bottom-up, since I knew some bottom of the solution. That´s the leaves of the functional decomposition tree. Where things became fuzzy, since the design did not cover any more details as with Find_factors(), I repeated the process in the small, so to speak: fake some top level, endure red high level tests, while first solving a simpler problem. Using scaffolding tests (to be thrown away at the end) brought two advantages: Encapsulation of the implementation details was not compromised. Naturally private methods could stay private. I did not need to make them internal or public just to be able to test them. I was able to write focused tests for small aspects of the solution. No need to test everything through the solution root, the API. The bottom line thus for me is: Informed TDD produces cleaner code in a systematic way. It conforms to core principles of programming: Single Responsibility Principle and/or Separation of Concerns. Distinct roles in development – being a researcher, being an engineer, being a craftsman – are represented as different phases. First find what, what there is. Then devise a solution. Then code the solution, manifest the solution in code. Writing tests first is a good practice. But it should not be taken dogmatic. And above all it should not be overloaded with purposes. And finally: moving from top to bottom through a design produces refactored code right away. Clean code thus almost is inevitable – and not left to a refactoring step at the end which is skipped often for different reasons.   PS: Yes, I have done this kata several times. But that has only an impact on the time needed for phases 1 and 2. I won´t skip them because of that. And there are no shortcuts during implementation because of that.

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  • High Load mysql on Debian server stops every day. Why?

    - by Oleg Abrazhaev
    I have Debian server with 32 gb memory. And there is apache2, memcached and nginx on this server. Memory load always on maximum. Only 500m free. Most memory leak do MySql. Apache only 70 clients configured, other services small memory usage. When mysql use all memory it stops. And nothing works, need mysql reboot. Mysql configured use maximum 24 gb memory. I have hight weight InnoDB bases. (400000 rows, 30 gb). And on server multithread daemon, that makes many inserts in this tables, thats why InnoDB. There is my mysql config. [mysqld] # # * Basic Settings # default-time-zone = "+04:00" user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp language = /usr/share/mysql/english skip-external-locking default-time-zone='Europe/Moscow' # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. # # * Fine Tuning # #low_priority_updates = 1 concurrent_insert = ALWAYS wait_timeout = 600 interactive_timeout = 600 #normal key_buffer_size = 2024M #key_buffer_size = 1512M #70% hot cache key_cache_division_limit= 70 #16-32 max_allowed_packet = 32M #1-16M thread_stack = 8M #40-50 thread_cache_size = 50 #orderby groupby sort sort_buffer_size = 64M #same myisam_sort_buffer_size = 400M #temp table creates when group_by tmp_table_size = 3000M #tables in memory max_heap_table_size = 3000M #on disk open_files_limit = 10000 table_cache = 10000 join_buffer_size = 5M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP #myisam_use_mmap = 1 max_connections = 200 thread_concurrency = 8 # # * Query Cache Configuration # #more ignored query_cache_limit = 50M query_cache_size = 210M #on query cache query_cache_type = 1 # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. #log = /var/log/mysql/mysql.log # # Error logging goes to syslog. This is a Debian improvement :) # # Here you can see queries with especially long duration log_slow_queries = /var/log/mysql/mysql-slow.log long_query_time = 1 log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log server-id = 1 log-bin = /var/lib/mysql/mysql-bin #replicate-do-db = gate log-bin-index = /var/lib/mysql/mysql-bin.index log-error = /var/lib/mysql/mysql-bin.err relay-log = /var/lib/mysql/relay-bin relay-log-info-file = /var/lib/mysql/relay-bin.info relay-log-index = /var/lib/mysql/relay-bin.index binlog_do_db = 24avia expire_logs_days = 10 max_binlog_size = 100M read_buffer_size = 4024288 innodb_buffer_pool_size = 5000M innodb_flush_log_at_trx_commit = 2 innodb_thread_concurrency = 8 table_definition_cache = 2000 group_concat_max_len = 16M #binlog_do_db = gate #binlog_ignore_db = include_database_name # # * BerkeleyDB # # Using BerkeleyDB is now discouraged as its support will cease in 5.1.12. #skip-bdb # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # You might want to disable InnoDB to shrink the mysqld process by circa 100MB. #skip-innodb # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 500M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 32M key_buffer_size = 512M # # * NDB Cluster # # See /usr/share/doc/mysql-server-*/README.Debian for more information. # # The following configuration is read by the NDB Data Nodes (ndbd processes) # not from the NDB Management Nodes (ndb_mgmd processes). # # [MYSQL_CLUSTER] # ndb-connectstring=127.0.0.1 # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ Please, help me make it stable. Memory used /etc/mysql # free total used free shared buffers cached Mem: 32930800 32766424 164376 0 139208 23829196 -/+ buffers/cache: 8798020 24132780 Swap: 33553328 44660 33508668 Maybe my problem not in memory, but MySQL stops every day. As you can see, cache memory free 24 gb. Thank to Michael Hampton? for correction. Load overage on server 3.5. Maybe hdd or another problem? Maybe my config not optimal for 30gb InnoDB ? I'm already try mysqltuner and tunung-primer.sh , but they marked all green. Mysqltuner output mysqltuner >> MySQLTuner 1.0.1 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.5.24-9-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 112G (Tables: 1528) [--] Data in InnoDB tables: 39G (Tables: 340) [--] Data in PERFORMANCE_SCHEMA tables: 0B (Tables: 17) [!!] Total fragmented tables: 344 -------- Performance Metrics ------------------------------------------------- [--] Up for: 8h 18m 33s (14M q [478.333 qps], 259K conn, TX: 9B, RX: 5B) [--] Reads / Writes: 84% / 16% [--] Total buffers: 10.5G global + 81.1M per thread (200 max threads) [OK] Maximum possible memory usage: 26.3G (83% of installed RAM) [OK] Slow queries: 1% (259K/14M) [!!] Highest connection usage: 100% (201/200) [OK] Key buffer size / total MyISAM indexes: 1.5G/5.6G [OK] Key buffer hit rate: 100.0% (6B cached / 1M reads) [OK] Query cache efficiency: 74.3% (8M cached / 11M selects) [OK] Query cache prunes per day: 0 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 247K sorts) [!!] Joins performed without indexes: 106025 [!!] Temporary tables created on disk: 49% (351K on disk / 715K total) [OK] Thread cache hit rate: 99% (249 created / 259K connections) [!!] Table cache hit rate: 15% (2K open / 13K opened) [OK] Open file limit used: 15% (3K/20K) [OK] Table locks acquired immediately: 99% (4M immediate / 4M locks) [!!] InnoDB data size / buffer pool: 39.4G/5.9G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce or eliminate persistent connections to reduce connection usage Adjust your join queries to always utilize indexes Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Increase table_cache gradually to avoid file descriptor limits Variables to adjust: max_connections (> 200) wait_timeout (< 600) interactive_timeout (< 600) join_buffer_size (> 5.0M, or always use indexes with joins) table_cache (> 10000) innodb_buffer_pool_size (>= 39G) Mysql primer output -- MYSQL PERFORMANCE TUNING PRIMER -- - By: Matthew Montgomery - MySQL Version 5.5.24-9-log x86_64 Uptime = 0 days 8 hrs 20 min 50 sec Avg. qps = 478 Total Questions = 14369568 Threads Connected = 16 Warning: Server has not been running for at least 48hrs. It may not be safe to use these recommendations To find out more information on how each of these runtime variables effects performance visit: http://dev.mysql.com/doc/refman/5.5/en/server-system-variables.html Visit http://www.mysql.com/products/enterprise/advisors.html for info about MySQL's Enterprise Monitoring and Advisory Service SLOW QUERIES The slow query log is enabled. Current long_query_time = 1.000000 sec. You have 260626 out of 14369701 that take longer than 1.000000 sec. to complete Your long_query_time seems to be fine BINARY UPDATE LOG The binary update log is enabled Binlog sync is not enabled, you could loose binlog records during a server crash WORKER THREADS Current thread_cache_size = 50 Current threads_cached = 45 Current threads_per_sec = 0 Historic threads_per_sec = 0 Your thread_cache_size is fine MAX CONNECTIONS Current max_connections = 200 Current threads_connected = 11 Historic max_used_connections = 201 The number of used connections is 100% of the configured maximum. You should raise max_connections INNODB STATUS Current InnoDB index space = 214 M Current InnoDB data space = 39.40 G Current InnoDB buffer pool free = 0 % Current innodb_buffer_pool_size = 5.85 G Depending on how much space your innodb indexes take up it may be safe to increase this value to up to 2 / 3 of total system memory MEMORY USAGE Max Memory Ever Allocated : 23.46 G Configured Max Per-thread Buffers : 15.84 G Configured Max Global Buffers : 7.54 G Configured Max Memory Limit : 23.39 G Physical Memory : 31.40 G Max memory limit seem to be within acceptable norms KEY BUFFER Current MyISAM index space = 5.61 G Current key_buffer_size = 1.47 G Key cache miss rate is 1 : 5578 Key buffer free ratio = 77 % Your key_buffer_size seems to be fine QUERY CACHE Query cache is enabled Current query_cache_size = 200 M Current query_cache_used = 101 M Current query_cache_limit = 50 M Current Query cache Memory fill ratio = 50.59 % Current query_cache_min_res_unit = 4 K MySQL won't cache query results that are larger than query_cache_limit in size SORT OPERATIONS Current sort_buffer_size = 64 M Current read_rnd_buffer_size = 256 K Sort buffer seems to be fine JOINS Current join_buffer_size = 5.00 M You have had 106606 queries where a join could not use an index properly You have had 8 joins without keys that check for key usage after each row join_buffer_size >= 4 M This is not advised You should enable "log-queries-not-using-indexes" Then look for non indexed joins in the slow query log. OPEN FILES LIMIT Current open_files_limit = 20210 files The open_files_limit should typically be set to at least 2x-3x that of table_cache if you have heavy MyISAM usage. Your open_files_limit value seems to be fine TABLE CACHE Current table_open_cache = 10000 tables Current table_definition_cache = 2000 tables You have a total of 1910 tables You have 2151 open tables. The table_cache value seems to be fine TEMP TABLES Current max_heap_table_size = 2.92 G Current tmp_table_size = 2.92 G Of 366426 temp tables, 49% were created on disk Perhaps you should increase your tmp_table_size and/or max_heap_table_size to reduce the number of disk-based temporary tables Note! BLOB and TEXT columns are not allow in memory tables. If you are using these columns raising these values might not impact your ratio of on disk temp tables. TABLE SCANS Current read_buffer_size = 3 M Current table scan ratio = 2846 : 1 read_buffer_size seems to be fine TABLE LOCKING Current Lock Wait ratio = 1 : 185 You may benefit from selective use of InnoDB. If you have long running SELECT's against MyISAM tables and perform frequent updates consider setting 'low_priority_updates=1'

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  • Class Mapping Error: 'T' must be a non-abstract type with a public parameterless constructor

    - by Amit Ranjan
    Hi, While mapping class i am getting error 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. Below is my SqlReaderBase Class public abstract class SqlReaderBase<T> : ConnectionProvider { #region Abstract Methods protected abstract string commandText { get; } protected abstract CommandType commandType { get; } protected abstract Collection<IDataParameter> GetParameters(IDbCommand command); **protected abstract MapperBase<T> GetMapper();** #endregion #region Non Abstract Methods /// <summary> /// Method to Execute Select Queries for Retrieveing List of Result /// </summary> /// <returns></returns> public Collection<T> ExecuteReader() { //Collection of Type on which Template is applied Collection<T> collection = new Collection<T>(); // initializing connection using (IDbConnection connection = GetConnection()) { try { // creates command for sql operations IDbCommand command = connection.CreateCommand(); // assign connection to command command.Connection = connection; // assign query command.CommandText = commandText; //state what type of query is used, text, table or Sp command.CommandType = commandType; // retrieves parameter from IDataParameter Collection and assigns it to command object foreach (IDataParameter param in GetParameters(command)) command.Parameters.Add(param); // Establishes connection with database server connection.Open(); // Since it is designed for executing Select statements that will return a list of results // so we will call command's execute reader method that return a Forward Only reader with // list of results inside. using (IDataReader reader = command.ExecuteReader()) { try { // Call to Mapper Class of the template to map the data to its // respective fields MapperBase<T> mapper = GetMapper(); collection = mapper.MapAll(reader); } catch (Exception ex) // catch exception { throw ex; // log errr } finally { reader.Close(); reader.Dispose(); } } } catch (Exception ex) { throw ex; } finally { connection.Close(); connection.Dispose(); } } return collection; } #endregion } What I am trying to do is , I am executine some command and filling my class dynamically. The class is given below: namespace FooZo.Core { public class Restaurant { #region Private Member Variables private int _restaurantId = 0; private string _email = string.Empty; private string _website = string.Empty; private string _name = string.Empty; private string _address = string.Empty; private string _phone = string.Empty; private bool _hasMenu = false; private string _menuImagePath = string.Empty; private int _cuisine = 0; private bool _hasBar = false; private bool _hasHomeDelivery = false; private bool _hasDineIn = false; private int _type = 0; private string _restaurantImagePath = string.Empty; private string _serviceAvailableTill = string.Empty; private string _serviceAvailableFrom = string.Empty; public string Name { get { return _name; } set { _name = value; } } public string Address { get { return _address; } set { _address = value; } } public int RestaurantId { get { return _restaurantId; } set { _restaurantId = value; } } public string Website { get { return _website; } set { _website = value; } } public string Email { get { return _email; } set { _email = value; } } public string Phone { get { return _phone; } set { _phone = value; } } public bool HasMenu { get { return _hasMenu; } set { _hasMenu = value; } } public string MenuImagePath { get { return _menuImagePath; } set { _menuImagePath = value; } } public string RestaurantImagePath { get { return _restaurantImagePath; } set { _restaurantImagePath = value; } } public int Type { get { return _type; } set { _type = value; } } public int Cuisine { get { return _cuisine; } set { _cuisine = value; } } public bool HasBar { get { return _hasBar; } set { _hasBar = value; } } public bool HasHomeDelivery { get { return _hasHomeDelivery; } set { _hasHomeDelivery = value; } } public bool HasDineIn { get { return _hasDineIn; } set { _hasDineIn = value; } } public string ServiceAvailableFrom { get { return _serviceAvailableFrom; } set { _serviceAvailableFrom = value; } } public string ServiceAvailableTill { get { return _serviceAvailableTill; } set { _serviceAvailableTill = value; } } #endregion public Restaurant() { } } } For filling my class properties dynamically i have another class called MapperBase Class with following methods: public abstract class MapperBase<T> where T : new() { protected T Map(IDataRecord record) { T instance = new T(); string fieldName; PropertyInfo[] properties = typeof(T).GetProperties(); for (int i = 0; i < record.FieldCount; i++) { fieldName = record.GetName(i); foreach (PropertyInfo property in properties) { if (property.Name == fieldName) { property.SetValue(instance, record[i], null); } } } return instance; } public Collection<T> MapAll(IDataReader reader) { Collection<T> collection = new Collection<T>(); while (reader.Read()) { collection.Add(Map(reader)); } return collection; } } There is another class which inherits the SqlreaderBaseClass called DefaultSearch. Code is below public class DefaultSearch: SqlReaderBase<Restaurant> { protected override string commandText { get { return "Select Name from vw_Restaurants"; } } protected override CommandType commandType { get { return CommandType.Text; } } protected override Collection<IDataParameter> GetParameters(IDbCommand command) { Collection<IDataParameter> parameters = new Collection<IDataParameter>(); parameters.Clear(); return parameters; } protected override MapperBase<Restaurant> GetMapper() { MapperBase<Restaurant> mapper = new RMapper(); return mapper; } } But whenever I tried to build , I am getting error 'T' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method. Even T here is Restaurant has a Parameterless Public constructor.

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  • Ruby on Rails: url_for :back leads to NoMethodError for back_url

    - by Platinum Azure
    Hi all, I'm trying to use url_for(:back) to create a redirect leading back to a previous page upon a user's logging in. I've had it working successfully for when the user just goes to the login page on his or her own. However, when the user is redirected to the login page due to accessing a page requiring that the user be authenticated, the redirect sends the user back to the page before the one s/he had tried to access with insufficient permissions. I'm trying to modify my login controller action to deal with the redirect properly. My plan is to have a query string parameter "redirect" that is used when a forced redirect occurs. In the controller, if that parameter exists that URL is used; otherwise, url_for(:back) is used, or if that doesn't work (due to lack of HTTP_REFERER), then the user is redirected to the site's home page. Here is the code snippet which is supposed to implement this logic: if params[:redirect] @url = params[:redirect] else @url = url_for :back @url ||= url_for :controller => "home", :action => "index" end The error I get is: NoMethodError in UsersController#login undefined method `back_url' for # RAILS_ROOT: [obscured] Application Trace | Framework Trace | Full Trace vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `__send__' vendor/rails/actionpack/lib/action_controller/polymorphic_routes.rb:112:in `polymorphic_url' vendor/rails/actionpack/lib/action_controller/base.rb:628:in `url_for' app/controllers/users_controller.rb:16:in `login' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:1256:in `perform_action_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:617:in `call_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' /usr/lib/ruby/1.8/benchmark.rb:293:in `measure' vendor/rails/actionpack/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue' vendor/rails/actionpack/lib/action_controller/rescue.rb:136:in `perform_action_without_caching' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:13:in `perform_action' vendor/rails/activerecord/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache' vendor/rails/activerecord/lib/active_record/query_cache.rb:8:in `cache' vendor/rails/actionpack/lib/action_controller/caching/sql_cache.rb:12:in `perform_action' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `send' vendor/rails/actionpack/lib/action_controller/base.rb:524:in `process_without_filters' vendor/rails/actionpack/lib/action_controller/filters.rb:606:in `process_without_session_management_support' vendor/rails/actionpack/lib/action_controller/session_management.rb:134:in `process' vendor/rails/actionpack/lib/action_controller/base.rb:392:in `process' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:184:in `handle_request' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:112:in `dispatch_unlocked' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:125:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `synchronize' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:124:in `dispatch' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:134:in `dispatch_cgi' vendor/rails/actionpack/lib/action_controller/dispatcher.rb:41:in `dispatch' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:76:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `synchronize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/rails.rb:74:in `process' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:159:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:158:in `process_client' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:285:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `initialize' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `new' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel.rb:268:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:282:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `each' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/configurator.rb:281:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:128:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/lib/mongrel/command.rb:212:in `run' /var/lib/gems/1.8/gems/mongrel-1.1.5/bin/mongrel_rails:281 vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load_without_new_constant_marking' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:142:in `load' vendor/rails/railties/lib/commands/servers/mongrel.rb:64 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in' vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require' vendor/rails/railties/lib/commands/server.rb:49 /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require' /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require' script/server:3 Request Parameters: None Show session dump --- :user: :csrf_id: 2927cca61bbbe97218362b5bcdb74c0f flash: !map:ActionController::Flash::FlashHash {} Response Headers: {"Content-Type"="", "cookie"=[], "Cache-Control"="no-cache"} Bear in mind that I had it working earlier-- url_for(:back) knew how to operate properly before I added this logic. Thanks in advance for any ideas!

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  • How to use Koala Facebook Graph API?

    - by reko
    I am a Rails newbie. I want to use Koala's Graph API. In my controller @graph = Koala::Facebook::API.new('myFacebookAccessToken') @hello = @graph.get_object("my.Name") When I do this, I get something like this { "id"=>"123456", "name"=>"First Middle Last", "first_name"=>"First", "middle_name"=>"Middle", "last_name"=>"Last", "link"=>"http://www.facebook.com/MyName", "username"=>"my.name", "birthday"=>"12/12/1212", "hometown"=>{"id"=>"115200305133358163", "name"=>"City, State"}, "location"=>{"id"=>"1054648928202133335", "name"=>"City, State"}, "bio"=>"This is my awesome Bio.", "quotes"=>"I am the master of my fate; I am the captain of my soul. - William Ernest Henley\r\n\r\n"Don't go around saying the world owes you a living. The world owes you nothing. It was here first.\" - Mark Twain", "work"=>[{"employer"=>{"id"=>"100751133333", "name"=>"Company1"}, "position"=>{"id"=>"105763693332790962", "name"=>"Position1"}, "start_date"=>"2010-08", "end_date"=>"2011-07"}], "sports"=>[{"id"=>"104019549633137", "name"=>"Sport1"}, {"id"=>"103992339636529", "name"=>"Sport2"}], "favorite_teams"=>[{"id"=>"105467226133353743", "name"=>"Fav1"}, {"id"=>"19031343444432369133", "name"=>"Fav2"}, {"id"=>"98027790139333", "name"=>"Fav3"}, {"id"=>"104055132963393331", "name"=>"Fav4"}, {"id"=>"191744431437533310", "name"=>"Fav5"}], "favorite_athletes"=>[{"id"=>"10836600585799922", "name"=>"Fava1"}, {"id"=>"18995689436787722", "name"=>"Fava2"}, {"id"=>"11156342219404022", "name"=>"Fava4"}, {"id"=>"11169998212279347", "name"=>"Fava5"}, {"id"=>"122326564475039", "name"=>"Fava6"}], "inspirational_people"=>[{"id"=>"16383141733798", "name"=>"Fava7"}, {"id"=>"113529011990793335", "name"=>"fava8"}, {"id"=>"112032333138809855566", "name"=>"Fava9"}, {"id"=>"10810367588423324", "name"=>"Fava10"}], "education"=>[{"school"=>{"id"=>"13478880321332322233663", "name"=>"School1"}, "type"=>"High School", "with"=>[{"id"=>"1401052755", "name"=>"Friend1"}]}, {"school"=>{"id"=>"11482777188037224", "name"=>"School2"}, "year"=>{"id"=>"138383069535219", "name"=>"2005"}, "type"=>"High School"}, {"school"=>{"id"=>"10604484633093514", "name"=>"School3"}, "year"=>{"id"=>"142963519060927", "name"=>"2010"}, "concentration"=>[{"id"=>"10407695629335773", "name"=>"c1"}], "type"=>"College"}, {"school"=>{"id"=>"22030497466330708", "name"=>"School4"}, "degree"=>{"id"=>"19233130157477979", "name"=>"c3"}, "year"=>{"id"=>"201638419856163", "name"=>"2011"}, "type"=>"Graduate School"}], "gender"=>"male", "interested_in"=>["female"], "relationship_status"=>"Single", "religion"=>"Religion1", "political"=>"Political1", "email"=>"[email protected]", "timezone"=>-8, "locale"=>"en_US", "languages"=>[{"id"=>"10605952233759137", "name"=>"English"}, {"id"=>"10337617475934611", "name"=>"L2"}, {"id"=>"11296944428713061", "name"=>"L3"}], "verified"=>true, "updated_time"=>"2012-02-24T04:18:05+0000" } How do I show this entire hash in the view in a good format? This is what I did from what ever I learnt.. In my view <% @hello.each do |key, value| %> <li><%=h "#{key.to_s} : #{value.to_s}" %></li> <% end %> This will get the entire thing converted to a list... It works awesome if its just one key.. but how to work with multiple keys and show only the information... something like when it outputs hometown : City, State rather than something like hometown : {"id"=>"115200305133358163", "name"=>"City, State"} Also for education if I just say education[school][name] to display list of schools attended? The error i get is can't convert String into Integer I also tried to do this in my controller, but I get the same error.. @fav_teams = @hello["favorite_teams"]["name"] Also, how can I save all these to the database.. something like just the list of all schools.. not their id no's? Update: The way I plan to save to my database is.. lets say for a user model, i want to save to database as :facebook_id, :facebook_name, :facebook_firstname, ...., :facebook_hometown .. here I only want to save name... when it comes to education.. I want to save.. school, concentration and type.. I have no idea on how to achieve this.. Looking forward for help! thanks!

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  • Why is my WCF Rest Service on IIS7 Authenticating TWICE!?!?

    - by TheAggie
    Ok, if someone could shed some light on this for me, I would greatly appreciate it. So here we go. I had a rest service running fine the other day but after I accidentally overwrote the web.config all hell broke loose. I've spent the past day and a half trying to sort things out but I can't seem to figure out what is missing or misplaced. So, I've designed this service around WCF Rest Contrib (http://wcfrestcontrib.codeplex.com)'s authentication process. Now, I can get this working fine on my localhost w/ the current web.config (minus the endpoint entry) but once I upload it to discountasp and select "basic authorization" in the ISS7 Manager, it appears that I'm getting authenticated twice! Once using my discount asp.net user/pass and then the next time using the application user/pass. Unfortunately I only provide one set of credentials and don't want to hard code my discountasp account info into the app. Like I said before, this worked fine a few days ago. Anyway. here is my web.config as it is now: <?xml version="1.0"?> <configuration> <connectionStrings> <add name="SQL2008_ConnectionString" connectionString="Data Source=sql2k8xx.discountasp.net;Initial Catalog=SQL2008_xx;Persist Security Info=True;User ID=SQL2008_xx_user;Password=myPass" providerName="System.Data.SqlClient" /> </connectionStrings> <system.web> <httpRuntime maxRequestLength="204800" executionTimeout="3600"/> <compilation debug="true"> <assemblies> <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/> <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/> </assemblies> </compilation> <httpModules> <add name="ServiceAnonymityModule" type="WcfRestContrib.Web.ServiceAnonymityModule, WcfRestContrib"/> </httpModules> </system.web> <system.codedom> <compilers> <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"> <providerOption name="CompilerVersion" value="v3.5"/> <providerOption name="WarnAsError" value="false"/> </compiler> </compilers> </system.codedom> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <modules> <remove name="ServiceAnonymityModule"/> <add name="ServiceAnonymityModule" type="WcfRestContrib.Web.ServiceAnonymityModule, WcfRestContrib"/> </modules> <handlers> <remove name="WebServiceHandlerFactory-Integrated"/> </handlers> </system.webServer> <system.diagnostics> <trace autoflush="true" /> </system.diagnostics> <system.serviceModel> <serviceHostingEnvironment aspNetCompatibilityEnabled="false"> <baseAddressPrefixFilters> <add prefix="http://www.mydomain.com/myServiceBaseAddress"/> </baseAddressPrefixFilters> </serviceHostingEnvironment> <extensions> <behaviorExtensions> <add name="webAuthentication" type="WcfRestContrib.ServiceModel.Configuration.WebAuthentication.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="errorHandler" type="WcfRestContrib.ServiceModel.Configuration.ErrorHandler.BehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="webFormatter" type="WcfRestContrib.ServiceModel.Configuration.WebDispatchFormatter.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> <add name="webErrorHandler" type="WcfRestContrib.ServiceModel.Configuration.WebErrorHandler.ConfigurationBehaviorElement, WcfRestContrib, Version=1.0.5.0, Culture=neutral, PublicKeyToken=89183999a8dc93b5"/> </behaviorExtensions> </extensions> <bindings> <customBinding> <binding name="HttpStreamedRest"> <httpTransport maxReceivedMessageSize="209715200" manualAddressing="true" /> </binding> <binding name="HttpsStreamedRest"> <httpsTransport maxReceivedMessageSize="209715200" manualAddressing="true" /> </binding> </customBinding> </bindings> <behaviors> <serviceBehaviors> <behavior name="Rest"> <webAuthentication requireSecureTransport="false" authenticationHandlerType="WcfRestContrib.ServiceModel.Dispatcher.WebBasicAuthenticationHandler, WcfRestContrib" usernamePasswordValidatorType="MyLibrary.Runtime.SecurityValidator, MyLibrary" source="MyRESTServiceRealm"/> <webFormatter> <formatters defaultMimeType="application/xml"> <formatter mimeTypes="application/xml,text/xml" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.PoxDataContract, WcfRestContrib"/> <formatter mimeTypes="application/json" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.DataContractJson, WcfRestContrib"/> <formatter mimeTypes="application/x-www-form-urlencoded" type="WcfRestContrib.ServiceModel.Dispatcher.Formatters.FormUrlEncoded, WcfRestContrib"/> </formatters> </webFormatter> <errorHandler errorHandlerType="WcfRestContrib.ServiceModel.Web.WebErrorHandler, WcfRestContrib"/> <webErrorHandler returnRawException="true" logHandlerType="MyLibrary.Runtime.LogHandler, MyLibrary" unhandledErrorMessage="An error has occured processing your request. Please contact technical support for further assistance."/> </behavior> </serviceBehaviors> </behaviors> </system.serviceModel> </configuration> So, whenever I upload this and change the ISS setting to Basic Authentication, it looks like it is trying to use the default handler for authentication as if I try to enter my web app user/pass, I get an error screen which has the following detailed information about the moduel/handler Detailed Error Information Module: IIS Web Core Notification: AuthenticateRequest Handler: svc-ISAPI-2.0 Error Code: 0x80070005 Requested URL: http://www.mydomain.com:80/MyService.../MyService.svc Physical Path: E:\web\xxxxxx\htdocs\MyServiceBaseAddress\MyService.svc Logon Method: Not yet determined Logon User: Not yet determined Now for the fun stuff... i tried providing my discountasp.net account username/password for kicks and sure enough it responded properly for any [OperationContract] which doesn't have [OperationAuthentication] defined (which is only one or two of the operations I have). I thought this was strange, so I looked at fiddler and saw something interesting. Whenever I try request a procedure with [OperationAuthentication] defined and provide my discountasp.net username/pass I get two different "WWW-Authenticate" headers back in Fiddler: WWW-Authenticate: Basic realm="MyRESTServiceRealm" WWW-Authenticate: Basic realm="www.mydomain.com" On the other hand, if I try to access the same procedures with only my application's user/pass, I only get the site's header: WWW-Authenticate: Basic realm="www.mydomain.com" My hypothesis is that for some reason I'm having to pass through the default "Basic Authorization" layer set by IIS before I can get to the application's "Custom Basic Authorization" layer. After verifying this by created an identical user/pass for my service that I use for my discountasp.net account, I was able to successfully pass both layers of authentication without any issues... so I think I can conclude that this is indeed the issue. Now how do I disable the default one? Do I need to do this in the IIS Manager, or in the web.config? Anyway, I have absolutely no idea how this is possible or what I need to do to resolve the issue, but I know that something is seriously out of whack. Any suggestions would be greatly appreciated! Thanks.

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  • Generating moderately interesting images

    - by Williham Totland
    Abstract: Can you propose a mathematical-ish algorithm over a plane of pixels that will generate a moderately interesting image, preferably one that on the whole resembles something? The story thus far: Once upon a time I decided in an effort to reduce cycle waste on my (admittedly too) numerous computers, and set out to generate images in a moderately interesting fashion; using a PRNG and some clever math to create images that would, on the whole, resemble something. Or at least, that was the plan. As it turns out, clever math requires being a clever mathematician; this I am not. At some length I arrived at a method that preferred straight lines (as these are generally the components of which our world is made), perhaps too strongly. The result is mildly interesting; resembling, perhaps, city grids as such: Now for the question proper: Given the source code of this little program; can you improve upon it and propose a method that gives somewhat more interesting results? (e.g. not city grids, but perhaps faces, animals, geography, what have you) This is also meant as a sort of challenge; I suppose and as such I've set down some completely arbitrary and equally optional rules: The comments in the code says it all really. Suggestions and "solutions" should edit the algorithm itself, not the surrounding framework, except as for to fix errors that prevents the sample from compiling. The code should compile cleanly with a standard issue C compiler. (If the example provided doesn't, oops! Tell me, and I'll fix. :) The method should, though again, this is optional, not need to elicit help from your friendly neighborhood math library. Solutions should probably be deliverable by simply yanking out whatever is between the snip lines (the ones that say you should not edit above and below, respectively), with a statement to the effect of what you need to add to the preamble in particular. The code requires a C compiler and libpng to build; I'm not entirely confident that the MinGW compiler provides the necessities, but I would be surprised if it didn't. For Debian you'll want the libpng-dev package, and for Mac OS X you'll want the XCode tools.. The source code can be downloaded here. Warning: Massive code splurge incoming! // compile with gcc -o imggen -lpng imggen.c // optionally with -DITERATIONS=x, where x is an appropriate integer // If you're on a Mac or using MinGW, you may have to fiddle with the linker flags to find the library and includes. #include <stdio.h> #include <stdlib.h> #include <png.h> #ifdef ITERATIONS #define REPEAT #endif // ITERATIONS // YOU MAY CHANGE THE FOLLOWING DEFINES #define WIDTH 320 #define HEIGHT 240 // YOU MAY REPLACE THE FOLLOWING DEFINES AS APPROPRIATE #define INK 16384 void writePNG (png_bytepp imageBuffer, png_uint_32 width, png_uint_32 height, int iteration) { char *fname; asprintf(&fname, "out.%d.png", iteration); FILE *fp = fopen(fname, "wb"); if (!fp) return; png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); png_infop info_ptr = png_create_info_struct(png_ptr); png_init_io(png_ptr, fp); png_set_filter(png_ptr, PNG_FILTER_TYPE_DEFAULT, PNG_FILTER_NONE); png_set_compression_level(png_ptr, Z_BEST_COMPRESSION); png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); png_set_rows(png_ptr, info_ptr, imageBuffer); png_set_invert_mono(png_ptr); /// YOU MAY COMMENT OUT THIS LINE png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL); png_destroy_write_struct(&png_ptr, &info_ptr); fclose(fp); free(fname); } int main (int argc, const char * argv[]) { png_uint_32 height = HEIGHT, width = WIDTH; int iteration = 1; #ifdef REPEAT for (iteration = 1; iteration <= ITERATIONS; iteration++) { #endif // REPEAT png_bytepp imageBuffer = malloc(sizeof(png_bytep) * height); for (png_uint_32 i = 0; i < height; i++) { imageBuffer[i] = malloc(sizeof(png_byte) * width); for (png_uint_32 j = 0; j < width; j++) { imageBuffer[i][j] = 0; } } /// CUT ACROSS THE DASHED LINES /// ------------------------------------------- /// NO EDITING ABOVE THIS LINE; EXCEPT AS NOTED int ink = INK; int x = rand() % width, y = rand() % height; int xdir = (rand() % 2)?1:-1; int ydir = (rand() % 2)?1:-1; while (ink) { imageBuffer[y][x] = 255; --ink; xdir += (rand() % 2)?(1):(-1); ydir += (rand() % 2)?(1):(-1); if (ydir > 0) { ++y; } else if (ydir < 0) { --y; } if (xdir > 0) { ++x; } else if (xdir < 0) { --x; } if (x == -1 || y == -1 || x == width || y == height || x == y && x == 0) { x = rand() % width; y = rand() % height; xdir = (rand() % 2)?1:-1; ydir = (rand() % 2)?1:-1; } } /// NO EDITING BELOW THIS LINE /// ------------------------------------------- writePNG(imageBuffer, width, height, iteration); for (png_uint_32 i = 0; i < height; i++) { free(imageBuffer[i]); } free(imageBuffer); #ifdef REPEAT } #endif // REPEAT return 0; } Note: While this question doesn't strictly speaking seem "answerable" as such; I still believe that it can give rise to some manner of "right" answer. Maybe. Happy hunting.

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  • Solving embarassingly parallel problems using Python multiprocessing

    - by gotgenes
    How does one use multiprocessing to tackle embarrassingly parallel problems? Embarassingly parallel problems typically consist of three basic parts: Read input data (from a file, database, tcp connection, etc.). Run calculations on the input data, where each calculation is independent of any other calculation. Write results of calculations (to a file, database, tcp connection, etc.). We can parallelize the program in two dimensions: Part 2 can run on multiple cores, since each calculation is independent; order of processing doesn't matter. Each part can run independently. Part 1 can place data on an input queue, part 2 can pull data off the input queue and put results onto an output queue, and part 3 can pull results off the output queue and write them out. This seems a most basic pattern in concurrent programming, but I am still lost in trying to solve it, so let's write a canonical example to illustrate how this is done using multiprocessing. Here is the example problem: Given a CSV file with rows of integers as input, compute their sums. Separate the problem into three parts, which can all run in parallel: Process the input file into raw data (lists/iterables of integers) Calculate the sums of the data, in parallel Output the sums Below is traditional, single-process bound Python program which solves these three tasks: #!/usr/bin/env python # -*- coding: UTF-8 -*- # basicsums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file. """ import csv import optparse import sys def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) return cli_parser def parse_input_csv(csvfile): """Parses the input CSV and yields tuples with the index of the row as the first element, and the integers of the row as the second element. The index is zero-index based. :Parameters: - `csvfile`: a `csv.reader` instance """ for i, row in enumerate(csvfile): row = [int(entry) for entry in row] yield i, row def sum_rows(rows): """Yields a tuple with the index of each input list of integers as the first element, and the sum of the list of integers as the second element. The index is zero-index based. :Parameters: - `rows`: an iterable of tuples, with the index of the original row as the first element, and a list of integers as the second element """ for i, row in rows: yield i, sum(row) def write_results(csvfile, results): """Writes a series of results to an outfile, where the first column is the index of the original row of data, and the second column is the result of the calculation. The index is zero-index based. :Parameters: - `csvfile`: a `csv.writer` instance to which to write results - `results`: an iterable of tuples, with the index (zero-based) of the original row as the first element, and the calculated result from that row as the second element """ for result_row in results: csvfile.writerow(result_row) def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # gets an iterable of rows that's not yet evaluated input_rows = parse_input_csv(in_csvfile) # sends the rows iterable to sum_rows() for results iterable, but # still not evaluated result_rows = sum_rows(input_rows) # finally evaluation takes place as a chain in write_results() write_results(out_csvfile, result_rows) infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) Let's take this program and rewrite it to use multiprocessing to parallelize the three parts outlined above. Below is a skeleton of this new, parallelized program, that needs to be fleshed out to address the parts in the comments: #!/usr/bin/env python # -*- coding: UTF-8 -*- # multiproc_sums.py """A program that reads integer values from a CSV file and writes out their sums to another CSV file, using multiple processes if desired. """ import csv import multiprocessing import optparse import sys NUM_PROCS = multiprocessing.cpu_count() def make_cli_parser(): """Make the command line interface parser.""" usage = "\n\n".join(["python %prog INPUT_CSV OUTPUT_CSV", __doc__, """ ARGUMENTS: INPUT_CSV: an input CSV file with rows of numbers OUTPUT_CSV: an output file that will contain the sums\ """]) cli_parser = optparse.OptionParser(usage) cli_parser.add_option('-n', '--numprocs', type='int', default=NUM_PROCS, help="Number of processes to launch [DEFAULT: %default]") return cli_parser def main(argv): cli_parser = make_cli_parser() opts, args = cli_parser.parse_args(argv) if len(args) != 2: cli_parser.error("Please provide an input file and output file.") infile = open(args[0]) in_csvfile = csv.reader(infile) outfile = open(args[1], 'w') out_csvfile = csv.writer(outfile) # Parse the input file and add the parsed data to a queue for # processing, possibly chunking to decrease communication between # processes. # Process the parsed data as soon as any (chunks) appear on the # queue, using as many processes as allotted by the user # (opts.numprocs); place results on a queue for output. # # Terminate processes when the parser stops putting data in the # input queue. # Write the results to disk as soon as they appear on the output # queue. # Ensure all child processes have terminated. # Clean up files. infile.close() outfile.close() if __name__ == '__main__': main(sys.argv[1:]) These pieces of code, as well as another piece of code that can generate example CSV files for testing purposes, can be found on github. I would appreciate any insight here as to how you concurrency gurus would approach this problem. Here are some questions I had when thinking about this problem. Bonus points for addressing any/all: Should I have child processes for reading in the data and placing it into the queue, or can the main process do this without blocking until all input is read? Likewise, should I have a child process for writing the results out from the processed queue, or can the main process do this without having to wait for all the results? Should I use a processes pool for the sum operations? If yes, what method do I call on the pool to get it to start processing the results coming into the input queue, without blocking the input and output processes, too? apply_async()? map_async()? imap()? imap_unordered()? Suppose we didn't need to siphon off the input and output queues as data entered them, but could wait until all input was parsed and all results were calculated (e.g., because we know all the input and output will fit in system memory). Should we change the algorithm in any way (e.g., not run any processes concurrently with I/O)?

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  • XSLT 1.0 recursion

    - by DashaLuna
    I'm stuck with recursion, was wondering if anyone can help me out with it. I have <Receipts> and <Deposits> elements, that are not verbose, i.e. that a <Receipts> element doesn't have an attribute to show what <Deposit> it is towards. I need to figure out <Deposits> "still amount due" and when a last receipt towards it was paid if any. I'm trying to do it with the following code: The idea was to take 1st deposit and see if there are receipts. If the deposit isn't fully paid and there are more receipts - call that recorsive function with all the same params except now count in following receipt. If there aren't any more receipts or deposit is payed - process it correctly (add required attributes). Otherwise proceed with 2nd deposit. And so on. However, the XSLT crashes with error message that "a processor stack has overflowed - possible cause is infinite template recursion" I would really appreciate any help/teps... I'm not that great with recursion and can't understand why mine here doesn't work. Thanks! :) <!-- Accumulate all the deposits with @DueAmount attribute --> <xsl:variable name="depositsClassified"> <xsl:call-template name="classifyDeposits"> <!-- a node-list of all Deposits elements ordered by DueDate Acs --> <xsl:with-param name="depositsAll" select="$deposits"/> <xsl:with-param name="depositPrevAmount" select="'0'"/> <!-- a node-list of all Receipts elements ordered by ReceivedDate Acs --> <xsl:with-param name="receiptsAll" select="$receiptsAsc"/> <xsl:with-param name="receiptCount" select="'1'"/> </xsl:call-template> </xsl:variable> <xsl:template name="classifyDeposits"> <xsl:param name="depositsAll"/> <xsl:param name="depositPrevAmount" select="'0'"/> <xsl:param name="receiptsAll"/> <xsl:param name="receiptCount"/> <xsl:if test="$deposits"> <!-- Do required operations for the 1st deposit --> <xsl:variable name="depositFirst" select="$depositsAll[1]"/> <xsl:variable name="receiptSum"> <xsl:choose> <xsl:when test="$receiptsAll"> <xsl:value-of select="sum($receiptsAll[position() &lt;= $receiptCount]/@ActionAmount)"/> </xsl:when> <xsl:otherwise>0</xsl:otherwise> </xsl:choose> </xsl:variable> <xsl:variable name="diff" select="$depositPrevAmount + $depositFirst/@DepositTotalAmount - $receiptSum"/> <xsl:choose> <xsl:when test="$diff &gt; 0 and $receiptCount &lt; $receiptsQuantityOf"> <xsl:call-template name="classifyDeposits"> <xsl:with-param name="depositsAll" select="$depositsAll"/> <xsl:with-param name="depositPrevAmount" select="$depositPrevAmount"/> <xsl:with-param name="receiptsAll" select="$receiptsAll"/> <xsl:with-param name="receiptCount" select="$receiptCount + 1"/> </xsl:call-template> </xsl:when> <xsl:otherwise> <!-- Record changes to the deposit (@DueAmount and receipt ReceivedDate) --> <xsl:apply-templates select="$depositFirst" mode="defineDeposit"> <xsl:with-param name="diff" select="$diff"/> <xsl:with-param name="latestReceiptForDeposit" select="$receiptsAll[position() = $receiptCount]"/> </xsl:apply-templates> <!-- Recursive call to the next deposit --> <xsl:call-template name="classifyDeposits"> <xsl:with-param name="depositsAll" select="$depositsAll[position() &gt; 1]"/> <xsl:with-param name="depositPrevAmount" select="$depositPrevAmount + $depositFirst/@DepositTotalAmount"/> <xsl:with-param name="receiptsAll" select="$receiptsAll"/> <xsl:with-param name="receiptCount" select="'1'"/> </xsl:call-template> </xsl:otherwise> </xsl:choose> </xsl:if> </xsl:template> <!-- Determine deposit's status, due amount and payment received date if any --> <xsl:template match="Deposits" mode="defineDeposit"> <xsl:param name="diff"/> <xsl:param name="latestReceiptForDeposit"/> <xsl:choose> <xsl:when test="$diff &lt;= 0"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'paid'"/> <xsl:with-param name="dueAmount" select="'0'"/> <xsl:with-param name="receipt" select="$latestReceiptForDeposit"/> </xsl:apply-templates> </xsl:when> <xsl:when test="$diff = ./@DepositTotalAmount"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'due'"/> <xsl:with-param name="dueAmount" select="$diff"/> </xsl:apply-templates> </xsl:when> <xsl:when test="$diff &lt; ./@DepositTotalAmount"> <xsl:apply-templates select="." mode="addAttrs"> <xsl:with-param name="status" select="'outstanding'"/> <xsl:with-param name="dueAmount" select="$diff"/> <xsl:with-param name="receipt" select="$latestReceiptForDeposit"/> </xsl:apply-templates> </xsl:when> <xsl:otherwise/> </xsl:choose> </xsl:template> <xsl:template match="Deposits" mode="addAttrs"> <xsl:param name="status"/> <xsl:param name="dueAmount"/> <xsl:param name="receipt" select="''"/> <!-- Constract a new MultiDeposits element with required info --> <xsl:copy> <xsl:copy-of select="./@*"/> <xsl:attribute name="Status"><xsl:value-of select="$status"/></xsl:attribute> <xsl:attribute name="DueAmount"><xsl:value-of select="$dueAmount"/></xsl:attribute> <xsl:if test="$receipt"> <xsl:attribute name="latestReceiptDate"> <xsl:value-of select="$receipt/@ActionDate"/> </xsl:attribute> </xsl:if> <xsl:copy-of select="./*"/> </xsl:copy> </xsl:template>

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  • Scala parser combinator runs out of memory

    - by user3217013
    I wrote the following parser in Scala using the parser combinators: import scala.util.parsing.combinator._ import scala.collection.Map import scala.io.StdIn object Keywords { val Define = "define" val True = "true" val False = "false" val If = "if" val Then = "then" val Else = "else" val Return = "return" val Pass = "pass" val Conj = ";" val OpenParen = "(" val CloseParen = ")" val OpenBrack = "{" val CloseBrack = "}" val Comma = "," val Plus = "+" val Minus = "-" val Times = "*" val Divide = "/" val Pow = "**" val And = "&&" val Or = "||" val Xor = "^^" val Not = "!" val Equals = "==" val NotEquals = "!=" val Assignment = "=" } //--------------------------------------------------------------------------------- sealed abstract class Op case object Plus extends Op case object Minus extends Op case object Times extends Op case object Divide extends Op case object Pow extends Op case object And extends Op case object Or extends Op case object Xor extends Op case object Not extends Op case object Equals extends Op case object NotEquals extends Op case object Assignment extends Op //--------------------------------------------------------------------------------- sealed abstract class Term case object TrueTerm extends Term case object FalseTerm extends Term case class FloatTerm(value : Float) extends Term case class StringTerm(value : String) extends Term case class Identifier(name : String) extends Term //--------------------------------------------------------------------------------- sealed abstract class Expression case class TermExp(term : Term) extends Expression case class UnaryOp(op : Op, exp : Expression) extends Expression case class BinaryOp(op : Op, left : Expression, right : Expression) extends Expression case class FuncApp(funcName : Term, args : List[Expression]) extends Expression //--------------------------------------------------------------------------------- sealed abstract class Statement case class ExpressionStatement(exp : Expression) extends Statement case class Pass() extends Statement case class Return(value : Expression) extends Statement case class AssignmentVar(variable : Term, exp : Expression) extends Statement case class IfThenElse(testBody : Expression, thenBody : Statement, elseBody : Statement) extends Statement case class Conjunction(left : Statement, right : Statement) extends Statement case class AssignmentFunc(functionName : Term, args : List[Term], body : Statement) extends Statement //--------------------------------------------------------------------------------- class myParser extends JavaTokenParsers { val keywordMap : Map[String, Op] = Map( Keywords.Plus -> Plus, Keywords.Minus -> Minus, Keywords.Times -> Times, Keywords.Divide -> Divide, Keywords.Pow -> Pow, Keywords.And -> And, Keywords.Or -> Or, Keywords.Xor -> Xor, Keywords.Not -> Not, Keywords.Equals -> Equals, Keywords.NotEquals -> NotEquals, Keywords.Assignment -> Assignment ) def floatTerm : Parser[Term] = decimalNumber ^^ { case x => FloatTerm( x.toFloat ) } def stringTerm : Parser[Term] = stringLiteral ^^ { case str => StringTerm(str) } def identifier : Parser[Term] = ident ^^ { case value => Identifier(value) } def boolTerm : Parser[Term] = (Keywords.True | Keywords.False) ^^ { case Keywords.True => TrueTerm case Keywords.False => FalseTerm } def simpleTerm : Parser[Expression] = (boolTerm | floatTerm | stringTerm) ^^ { case term => TermExp(term) } def argument = expression def arguments_aux : Parser[List[Expression]] = (argument <~ Keywords.Comma) ~ arguments ^^ { case arg ~ argList => arg :: argList } def arguments = arguments_aux | { argument ^^ { case arg => List(arg) } } def funcAppArgs : Parser[List[Expression]] = funcEmptyArgs | ( Keywords.OpenParen ~> arguments <~ Keywords.CloseParen ^^ { case args => args.foldRight(List[Expression]()) ( (a,b) => a :: b ) } ) def funcApp = identifier ~ funcAppArgs ^^ { case funcName ~ argList => FuncApp(funcName, argList) } def variableTerm : Parser[Expression] = identifier ^^ { case name => TermExp(name) } def atomic_expression = simpleTerm | funcApp | variableTerm def paren_expression : Parser[Expression] = Keywords.OpenParen ~> expression <~ Keywords.CloseParen def unary_operation : Parser[String] = Keywords.Not def unary_expression : Parser[Expression] = operation(0) ~ expression(0) ^^ { case op ~ exp => UnaryOp(keywordMap(op), exp) } def operation(precedence : Int) : Parser[String] = precedence match { case 0 => Keywords.Not case 1 => Keywords.Pow case 2 => Keywords.Times | Keywords.Divide | Keywords.And case 3 => Keywords.Plus | Keywords.Minus | Keywords.Or | Keywords.Xor case 4 => Keywords.Equals | Keywords.NotEquals case _ => throw new Exception("No operations with this precedence.") } def binary_expression(precedence : Int) : Parser[Expression] = precedence match { case 0 => throw new Exception("No operation with zero precedence.") case n => (expression (n-1)) ~ operation(n) ~ (expression (n)) ^^ { case left ~ op ~ right => BinaryOp(keywordMap(op), left, right) } } def expression(precedence : Int) : Parser[Expression] = precedence match { case 0 => unary_expression | paren_expression | atomic_expression case n => binary_expression(n) | expression(n-1) } def expression : Parser[Expression] = expression(4) def expressionStmt : Parser[Statement] = expression ^^ { case exp => ExpressionStatement(exp) } def assignment : Parser[Statement] = (identifier <~ Keywords.Assignment) ~ expression ^^ { case varName ~ exp => AssignmentVar(varName, exp) } def ifthen : Parser[Statement] = ((Keywords.If ~ Keywords.OpenParen) ~> expression <~ Keywords.CloseParen) ~ ((Keywords.Then ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ^^ { case ifBody ~ thenBody => IfThenElse(ifBody, thenBody, Pass()) } def ifthenelse : Parser[Statement] = ((Keywords.If ~ Keywords.OpenParen) ~> expression <~ Keywords.CloseParen) ~ ((Keywords.Then ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ~ ((Keywords.Else ~ Keywords.OpenBrack) ~> statements <~ Keywords.CloseBrack) ^^ { case ifBody ~ thenBody ~ elseBody => IfThenElse(ifBody, thenBody, elseBody) } def pass : Parser[Statement] = Keywords.Pass ^^^ { Pass() } def returnStmt : Parser[Statement] = Keywords.Return ~> expression ^^ { case exp => Return(exp) } def statement : Parser[Statement] = ((pass | returnStmt | assignment | expressionStmt) <~ Keywords.Conj) | ifthenelse | ifthen def statements_aux : Parser[Statement] = statement ~ statements ^^ { case st ~ sts => Conjunction(st, sts) } def statements : Parser[Statement] = statements_aux | statement def funcDefBody : Parser[Statement] = Keywords.OpenBrack ~> statements <~ Keywords.CloseBrack def funcEmptyArgs = Keywords.OpenParen ~ Keywords.CloseParen ^^^ { List() } def funcDefArgs : Parser[List[Term]] = funcEmptyArgs | Keywords.OpenParen ~> repsep(identifier, Keywords.Comma) <~ Keywords.CloseParen ^^ { case args => args.foldRight(List[Term]()) ( (a,b) => a :: b ) } def funcDef : Parser[Statement] = (Keywords.Define ~> identifier) ~ funcDefArgs ~ funcDefBody ^^ { case funcName ~ funcArgs ~ body => AssignmentFunc(funcName, funcArgs, body) } def funcDefAndStatement : Parser[Statement] = funcDef | statement def funcDefAndStatements_aux : Parser[Statement] = funcDefAndStatement ~ funcDefAndStatements ^^ { case stmt ~ stmts => Conjunction(stmt, stmts) } def funcDefAndStatements : Parser[Statement] = funcDefAndStatements_aux | funcDefAndStatement def parseProgram : Parser[Statement] = funcDefAndStatements def eval(input : String) = { parseAll(parseProgram, input) match { case Success(result, _) => result case Failure(m, _) => println(m) case _ => println("") } } } object Parser { def main(args : Array[String]) { val x : myParser = new myParser() println(args(0)) val lines = scala.io.Source.fromFile(args(0)).mkString println(x.eval(lines)) } } The problem is, when I run the parser on the following example it works fine: define foo(a) { if (!h(IM) && a) then { return 0; } if (a() && !h()) then { return 0; } } But when I add threes characters in the first if statement, it runs out of memory. This is absolutely blowing my mind. Can anyone help? (I suspect it has to do with repsep, but I am not sure.) define foo(a) { if (!h(IM) && a(1)) then { return 0; } if (a() && !h()) then { return 0; } } EDIT: Any constructive comments about my Scala style is also appreciated.

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  • Connection drop problem with Hibernate-mysql-c3p0

    - by user344788
    hi all, This is an issue which I have seen all across the web. I will bring it up again as till now I don't have a fix for the same. I am using hibernate 3. mysql 5 and latest c3p0 jar. I am getting a broken pipe exception. Following is my hibernate.cfg file. com.mysql.jdbc.Driver org.hibernate.dialect.MySQLDialect <property name="hibernate.show_sql">true</property> <property name="hibernate.use_sql_comments">true</property> <property name="hibernate.current_session_context_class">thread</property> <property name="connection.autoReconnect">true</property> <property name="connection.autoReconnectForPools">true</property> <property name="connection.is-connection-validation-required">true</property> <!--<property name="c3p0.min_size">5</property> <property name="c3p0.max_size">20</property> <property name="c3p0.timeout">1800</property> <property name="c3p0.max_statements">50</property> --><property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider </property> <property name="hibernate.c3p0.acquireRetryAttempts">30</property> <property name="hibernate.c3p0.acquireIncrement">5</property> <property name="hibernate.c3p0.automaticTestTable">C3P0TestTable</property> <property name="hibernate.c3p0.idleConnectionTestPeriod">36000</property> <property name="hibernate.c3p0.initialPoolSize">20</property> <property name="hibernate.c3p0.maxPoolSize">100</property> <property name="hibernate.c3p0.maxIdleTime">1200</property> <property name="hibernate.c3p0.maxStatements">50</property> <property name="hibernate.c3p0.minPoolSize">10</property>--> My connection pooling is occurring fine. During the day it is fine , but once i keep it idle over the night ,next day I find it giving me broken connection error. public class HibernateUtil { private static Logger log = Logger.getLogger(HibernateUtil.class); //private static Log log = LogFactory.getLog(HibernateUtil.class); private static Configuration configuration; private static SessionFactory sessionFactory; static { // Create the initial SessionFactory from the default configuration files try { log.debug("Initializing Hibernate"); // Read hibernate.properties, if present configuration = new Configuration(); // Use annotations: configuration = new AnnotationConfiguration(); // Read hibernate.cfg.xml (has to be present) configuration.configure(); // Build and store (either in JNDI or static variable) rebuildSessionFactory(configuration); log.debug("Hibernate initialized, call HibernateUtil.getSessionFactory()"); } catch (Throwable ex) { // We have to catch Throwable, otherwise we will miss // NoClassDefFoundError and other subclasses of Error log.error("Building SessionFactory failed.", ex); throw new ExceptionInInitializerError(ex); } } /** * Returns the Hibernate configuration that was used to build the SessionFactory. * * @return Configuration */ public static Configuration getConfiguration() { return configuration; } /** * Returns the global SessionFactory either from a static variable or a JNDI lookup. * * @return SessionFactory */ public static SessionFactory getSessionFactory() { String sfName = configuration.getProperty(Environment.SESSION_FACTORY_NAME); System.out.println("Current s name is "+sfName); if ( sfName != null) { System.out.println("Looking up SessionFactory in JNDI"); log.debug("Looking up SessionFactory in JNDI"); try { System.out.println("Returning new sssion factory"); return (SessionFactory) new InitialContext().lookup(sfName); } catch (NamingException ex) { throw new RuntimeException(ex); } } else if (sessionFactory == null) { System.out.println("calling rebuild session factory now"); rebuildSessionFactory(); } return sessionFactory; } /** * Closes the current SessionFactory and releases all resources. * <p> * The only other method that can be called on HibernateUtil * after this one is rebuildSessionFactory(Configuration). */ public static void shutdown() { log.debug("Shutting down Hibernate"); // Close caches and connection pools getSessionFactory().close(); // Clear static variables sessionFactory = null; } /** * Rebuild the SessionFactory with the static Configuration. * <p> * Note that this method should only be used with static SessionFactory * management, not with JNDI or any other external registry. This method also closes * the old static variable SessionFactory before, if it is still open. */ public static void rebuildSessionFactory() { log.debug("Using current Configuration to rebuild SessionFactory"); rebuildSessionFactory(configuration); } /** * Rebuild the SessionFactory with the given Hibernate Configuration. * <p> * HibernateUtil does not configure() the given Configuration object, * it directly calls buildSessionFactory(). This method also closes * the old static variable SessionFactory before, if it is still open. * * @param cfg */ public static void rebuildSessionFactory(Configuration cfg) { log.debug("Rebuilding the SessionFactory from given Configuration"); if (sessionFactory != null && !sessionFactory.isClosed()) sessionFactory.close(); if (cfg.getProperty(Environment.SESSION_FACTORY_NAME) != null) { log.debug("Managing SessionFactory in JNDI"); cfg.buildSessionFactory(); } else { log.debug("Holding SessionFactory in static variable"); sessionFactory = cfg.buildSessionFactory(); } configuration = cfg; } } Above is my code for the session factory. And I have only select operations . And below is the method which is used most often to execute my select queries. One tricky thing which I am not understanding is in my findById method i am using this line of code getSession().beginTransaction(); without which it gives me an error saying that this cannot happpen without a transaction. But nowhere I am closing this transaction. And thers no method to close a transaction apart from commit or rollback (as far as i know) which are not applicable for select statements. public T findById(ID id, boolean lock) throws HibernateException, DAOException { log.debug("findNyId invoked with ID ="+id+"and lock ="+lock); T entity; getSession().beginTransaction(); if (lock) entity = (T) getSession().load(getPersistentClass(), id, LockMode.UPGRADE); else entity = (T) getSession().load(getPersistentClass(), id); return entity; } Can anyone please suggest what can I do ? I have tried out almost every solution available via googling, on stackoverlow or on hibernate forums with no avail. (And increasing wait_timeout on mysql is not a valid option in my case).

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  • WCF timeout exception detailed investigation

    - by Jason Kealey
    We have an application that has a WCF service (*.svc) running on IIS7 and various clients querying the service. The server is running Win 2008 Server. The clients are running either Windows 2008 Server or Windows 2003 server. I am getting the following exception, which I have seen can in fact be related to a large number of potential WCF issues. System.TimeoutException: The request channel timed out while waiting for a reply after 00:00:59.9320000. Increase the timeout value passed to the call to Request or increase the SendTimeout value on the Binding. The time allotted to this operation may have been a portion of a longer timeout. ---> System.TimeoutException: The HTTP request to 'http://www.domain.com/WebServices/myservice.svc/gzip' has exceeded the allotted timeout of 00:01:00. The time allotted to this operation may have been a portion of a longer timeout. I have increased the timeout to 30min and the error still occurred. This tells me that something else is at play, because the quantity of data could never take 30min to upload or download. The error comes and goes. At the moment, it is more frequent. It does not seem to matter if I have 3 clients running simultaneously or 100, it still occurs once in a while. Most of the time, there are no timeouts but I still get a few per hour. The error comes from any of the methods that are invoked. One of these methods does not have parameters and returns a bit of data. Another takes in lots of data as a parameter but executes asynchronously. The errors always originate from the client and never reference any code on the server in the stack trace. It always ends with: at System.Net.HttpWebRequest.GetResponse() at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelRequest.WaitForReply(TimeSpan timeout) On the server: I've tried (and currently have) the following binding settings: maxBufferSize="2147483647" maxReceivedMessageSize="2147483647" maxBufferPoolSize="2147483647" It does not seem to have an impact. I've tried (and currently have) the following throttling settings: <serviceThrottling maxConcurrentCalls="1500" maxConcurrentInstances="1500" maxConcurrentSessions="1500"/> It does not seem to have an impact. I currently have the following settings for the WCF service. [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Single)] I ran with ConcurrencyMode.Multiple for a while, and the error still occurred. I've tried restarting IIS, restarting my underlying SQL Server, restarting the machine. All of these don't seem to have an impact. I've tried disabling the Windows firewall. It does not seem to have an impact. On the client, I have these settings: maxReceivedMessageSize="2147483647" <system.net> <connectionManagement> <add address="*" maxconnection="16"/> </connectionManagement> </system.net> My client closes its connections: var client = new MyClient(); try { return client.GetConfigurationOptions(); } finally { client.Close(); } I have changed the registry settings to allow more outgoing connections: MaxConnectionsPerServer=24, MaxConnectionsPer1_0Server=32. I have now just recently tried SvcTraceViewer.exe. I managed to catch one exception on the client end. I see that its duration is 1 minute. Looking at the server side trace, I can see that the server is not aware of this exception. The maximum duration I can see is 10 seconds. I have looked at active database connections using exec sp_who on the server. I only have a few (2-3). I have looked at TCP connections from one client using TCPview. It usually is around 2-3 and I have seen up to 5 or 6. Simply put, I am stumped. I have tried everything I could find, and must be missing something very simple that a WCF expert would be able to see. It is my gut feeling that something is blocking my clients at the low-level (TCP), before the server actually receives the message and/or that something is queuing the messages at the server level and never letting them process. If you have any performance counters I should look at, please let me know. (please indicate what values are bad, as some of these counters are hard to decypher). Also, how could I log the WCF message size? Finally, are there any tools our there that would allow me to test how many connections I can establish between my client and server (independently from my application) Thanks for your time! Extra information added June 20th: My WCF application does something similar to the following. while (true) { Step1GetConfigurationSettingsFromServerViaWCF(); // can change between calls Step2GetWorkUnitFromServerViaWCF(); DoWorkLocally(); // takes 5-15minutes. Step3SendBackResultsToServerViaWCF(); } Using WireShark, I did see that when the error occurs, I have a five TCP retransmissions followed by a TCP reset later on. My guess is the RST is coming from WCF killing the connection. The exception report I get is from Step3 timing out. I discovered this by looking at the tcp stream "tcp.stream eq 192". I then expanded my filter to "tcp.stream eq 192 and http and http.request.method eq POST" and saw 6 POSTs during this stream. This seemed odd, so I checked with another stream such as tcp.stream eq 100. I had three POSTs, which seems a bit more normal because I am doing three calls. However, I do close my connection after every WCF call, so I would have expected one call per stream (but I don't know much about TCP). Investigating a bit more, I dumped the http packet load to disk to look at what these six calls where. 1) Step3 2) Step1 3) Step2 4) Step3 - corrupted 5) Step1 6) Step2 My guess is two concurrent clients are using the same connection, that is why I saw duplicates. However, I still have a few more issues that I can't comprehend: a) Why is the packet corrupted? Random network fluke - maybe? The load is gzipped using this sample code: http://msdn.microsoft.com/en-us/library/ms751458.aspx - Could the code be buggy once in a while when used concurrently? I should test without the gzip library. b) Why would I see step 1 & step 2 running AFTER the corrupted operation timed out? It seems to me as if these operations should not have occurred. Maybe I am not looking at the right stream because my understanding of TCP is flawed. I have other streams that occur at the same time. I should investigate other streams - a quick glance at streams 190-194 show that the Step3 POST have proper payload data (not corrupted). Pushing me to look at the gzip library again.

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  • Ideas for multiplatform encrypted java mobile storage system

    - by Fernando Miguélez
    Objective I am currently designing the API for a multiplatform storage system that would offer same interface and capabilities accross following supported mobile Java Platforms: J2ME. Minimum configuration/profile CLDC 1.1/MIDP 2.0 with support for some necessary JSRs (JSR-75 for file storage). Android. No minimum platform version decided yet, but rather likely could be API level 7. Blackberry. It would use the same base source of J2ME but taking advantage of some advaced capabilities of the platform. No minimum configuration decided yet (maybe 4.6 because of 64 KB limitation for RMS on 4.5). Basically the API would sport three kind of stores: Files. These would allow standard directory/file manipulation (read/write through streams, create, mkdir, etc.). Preferences. It is a special store that handles properties accessed through keys (Similar to plain old java properties file but supporting some improvements such as different value data types such as SharedPreferences on Android platform) Local Message Queues. This store would offer basic message queue functionality. Considerations Inspired on JSR-75, all types of stores would be accessed in an uniform way by means of an URL following RFC 1738 conventions, but with custom defined prefixes (i.e. "file://" for files, "prefs://" for preferences or "queue://" for message queues). The address would refer to a virtual location that would be mapped to a physical storage object by each mobile platform implementation. Only files would allow hierarchical storage (folders) and access to external extorage memory cards (by means of a unit name, the same way as in JSR-75, but that would not change regardless of underlying platform). The other types would only support flat storage. The system should also support a secure version of all basic types. The user would indicate it by prefixing "s" to the URL (i.e. "sfile://" instead of "file://"). The API would only require one PIN (introduced only once) to access any kind of secure object types. Implementation issues For the implementation of both plaintext and encrypted stores, I would use the functionality available on the underlying platforms: Files. These are available on all platforms (J2ME only with JSR-75, but it is mandatory for our needs). The abstract File to actual File mapping is straight except for addressing issues. RMS. This type of store available on J2ME (and Blackberry) platforms is convenient for Preferences and maybe Message Queues (though depending on performance or size requirements these could be implemented by means of normal files). SharedPreferences. This type of storage, only available on Android, would match Preferences needs. SQLite databases. This could be used for message queues on Android (and maybe Blackberry). When it comes to encryption some requirements should be met: To ease the implementation it will be carried out on read/write operations basis on streams (for files), RMS Records, SharedPreferences key-value pairs, SQLite database columns. Every underlying storage object should use the same encryption key. Handling of encrypted stores should be the same as the unencrypted counterpart. The only difference (from the user point of view) accessing an encrypted store would be the addressing. The user PIN provides access to any secure storage object, but the change of it would not require to decrypt/re-encrypt all the encrypted data. Cryptographic capabilities of underlying platform should be used whenever it is possible, so we would use: J2ME: SATSA-CRYPTO if it is available (not mandatory) or lightweight BoncyCastle cryptographic framework for J2ME. Blackberry: RIM Cryptographic API or BouncyCastle Android: JCE with integraced cryptographic provider (BouncyCastle?) Doubts Having reached this point I was struck by some doubts about what solution would be more convenient, taking into account the limitation of the plataforms. These are some of my doubts: Encryption Algorithm for data. Would AES-128 be strong and fast enough? What alternatives for such scenario would you suggest? Encryption Mode. I have read about the weakness of ECB encryption versus CBC, but in this case the first would have the advantage of random access to blocks, which is interesting for seek functionality on files. What type of encryption mode would you choose instead? Is stream encryption suitable for this case? Key generation. There could be one key generated for each storage object (file, RMS RecordStore, etc.) or just use one for all the objects of the same type. The first seems "safer", though it would require some extra space on device. In your opinion what would the trade-offs of each? Key storage. For this case using a standard JKS (or PKCS#12) KeyStore file could be suited to store encryption keys, but I could also define a smaller structure (encryption-transformation / key data / checksum) that could be attached to each storage store (i.e. using addition files with the same name and special extension for plain files or embedded inside other types of objects such as RMS Record Stores). What approach would you prefer? And when it comes to using a standard KeyStore with multiple-key generation (given this is your preference), would it be better to use a record-store per storage object or just a global KeyStore keeping all keys (i.e. using the URL identifier of abstract storage object as alias)? Master key. The use of a master key seems obvious. This key should be protected by user PIN (introduced only once) and would allow access to the rest of encryption keys (they would be encrypted by means of this master key). Changing the PIN would only require to reencrypt this key and not all the encrypted data. Where would you keep it taking into account that if this got lost all data would be no further accesible? What further considerations should I take into account? Platform cryptography support. Do SATSA-CRYPTO-enabled J2ME phones really take advantage of some dedicated hardware acceleration (or other advantage I have not foreseen) and would this approach be prefered (whenever possible) over just BouncyCastle implementation? For the same reason is RIM Cryptographic API worth the license cost over BouncyCastle? Any comments, critics, further considerations or different approaches are welcome.

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  • C++ cin keeps skipping.....

    - by user69514
    I am having problems with my program. WHen I run it, it asks the user for the album, the title, but then it just exits the loop without asking for the price and the sale tax. Any ideas what's going on? This is a sample run Discounts effective for September 15, 2010 Classical 8% Country 4% International 17% Jazz 0% Rock 16% Show 12% Are there more transactions? Y/N y Enter Artist of CD: Sevendust Enter Title of CD: Self titled Enter Genre of CD: Rock enter price Are there more transactions? Y/N Thank you for shopping with us! Program code: #include <iostream> #include <string> using namespace std; int counter = 0; string discount_tiles[] = {"Classical", "Country", "International", "Jazz", "Rock", "Show"}; int discount_amounts[] = {8, 4, 17, 0, 16, 12, 14}; string date = "September 15, 2010"; // Array Declerations //Artist array char** artist = new char *[100]; //Title array char** title = new char *[100]; //Genres array char** genres = new char *[100]; //Price array double* price[100]; //Discount array double* tax[100]; // sale price array double* sale_price[100]; //sale tax array double* sale_tax[100]; //cash price array double* cash_price[100]; //Begin Prototypes char* getArtist(); char* getTitle(); char* getGenre(); double* getPrice(); double* getTax(); unsigned int* AssignDiscounts(); void ReadTransaction (char ** artist, char ** title, char ** genre, float ** cash, float & taxrate, int albumcount); void computesaleprice(); bool AreThereMore (); //End Prototypes bool areThereMore () { char answer; cout << "Are there more transactions? Y/N" << endl; cin >> answer; if (answer =='y' || answer =='Y') return true; else return false; } char* getArtist() { char * artist= new char [100]; cout << "Enter Artist of CD: " << endl; cin.getline(artist,100); cin.ignore(); return artist; } char* getTitle() { char * title= new char [100]; cout << "Enter Title of CD: " << endl; cin.getline(title,100); cin.ignore(); return title; } char* getGenre() { char * genre= new char [100]; cout << "Enter Genre of CD: " << endl; cin.getline(genre,100); cin.ignore(); return genre; } double* getPrice() { //double* price = new double(); //cout << "Enter Price of CD: " << endl; //cin >> *price; //return price; double p = 0.0; cout<< "enter price" << endl; cin >> p; cin.ignore(); double* pp = &p; return pp; } double* getTax() { double* tax= new double(); cout << "Enter local sales tax: " << endl; cin >> *tax; return tax; } int findDiscount(string str){ if(str.compare(discount_tiles[0]) == 0) return discount_amounts[0]; else if(str.compare(discount_tiles[0]) == 0) return discount_amounts[1]; else if(str.compare(discount_tiles[0]) == 0) return discount_amounts[2]; else if(str.compare(discount_tiles[0]) == 0) return discount_amounts[3]; else if(str.compare(discount_tiles[0]) == 0) return discount_amounts[4]; else if(str.compare(discount_tiles[0]) == 0) return discount_amounts[5]; else{ cout << "Error in findDiscount function" << endl; return 0; } } void computesaleprice() { /** fill in array for all purchases **/ for( int i=0; i<=counter; i++){ double temp = *price[i]; temp -= findDiscount(genres[i]); double* tmpPntr = new double(); tmpPntr = &temp; sale_price[i] = tmpPntr; delete(&temp); delete(tmpPntr); } } void printDailyDiscounts(){ cout << "Discounts effective for " << date << endl; for(int i=0; i < 6; i++){ cout << discount_tiles[i] << "\t" << discount_amounts[i] << "%" << endl; } } //Begin Main int main () { for( int i=0; i<100; i++){ artist[i]=new char [100]; title[i]=new char [100]; genres[i]=new char [100]; price[i] = new double(0.0); tax[i] = new double(0.0); } // End Array Decleration printDailyDiscounts(); bool flag = true; while(flag == true){ if(areThereMore() == true){ artist[counter] = getArtist(); title[counter] = getTitle(); genres[counter] = getGenre(); price[counter] = getPrice(); //tax[counter] = getTax(); //counter++; flag = true; } else { flag = false; } } //compute sale prices //computesaleprice(); cout << "Thank you for shopping with us!" << endl; return 0; } //End Main /** void ReadTransaction (char ** artist, char ** title, char ** genre, float ** cash, float & taxrate, int albumcount) { strcpy(artist[albumcount],getArtist()); strcpy(title[albumcount],getTitle()); strcpy(genre[albumcount],getGenre()); //cash[albumcount][0]=computesaleprice();??????? //taxrate=getTax;?????????????? } * * */ unsigned int * AssignDiscounts() { unsigned int * discount = new unsigned int [7]; cout << "Enter Classical Discount: " << endl; cin >> discount[0]; cout << "Enter Country Discount: " << endl; cin >> discount[1]; cout << "Enter International Discount: " << endl; cin >> discount[2]; cout << "Enter Jazz Discount: " << endl; cin >> discount[3]; cout << "Enter Pop Discount: " << endl; cin >> discount[4]; cout << "Enter Rock Discount: " << endl; cin >> discount[5]; cout << "Enter Show Discount: " << endl; cin >> discount[6]; return discount; } /** char ** AssignGenres () { char ** genres = new char * [7]; for (int x=0;x<7;x++) genres[x] = new char [20]; strcpy(genres [0], "Classical"); strcpy(genres [1], "Country"); strcpy(genres [2], "International"); strcpy(genres [3], "Jazz"); strcpy(genres [4], "Pop"); strcpy(genres [5], "Rock"); strcpy(genres [6], "Show"); return genres; } **/ float getTax(float taxrate) { cout << "Please enter store tax rate: " << endl; cin >> taxrate; return taxrate; }

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  • g++ SSE intrinsics dilemma - value from intrinsic "saturates"

    - by Sriram
    Hi, I wrote a simple program to implement SSE intrinsics for computing the inner product of two large (100000 or more elements) vectors. The program compares the execution time for both, inner product computed the conventional way and using intrinsics. Everything works out fine, until I insert (just for the fun of it) an inner loop before the statement that computes the inner product. Before I go further, here is the code: //this is a sample Intrinsics program to compute inner product of two vectors and compare Intrinsics with traditional method of doing things. #include <iostream> #include <iomanip> #include <xmmintrin.h> #include <stdio.h> #include <time.h> #include <stdlib.h> using namespace std; typedef float v4sf __attribute__ ((vector_size(16))); double innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume len1 = len2. float result = 0.0; for(int i = 0; i < len1; i++) { for(int j = 0; j < len1; j++) { result += (arr1[i] * arr2[i]); } } //float y = 1.23e+09; //cout << "y = " << y << endl; return result; } double sse_v4sf_innerProduct(float* arr1, int len1, float* arr2, int len2) { //assume that len1 = len2. if(len1 != len2) { cout << "Lengths not equal." << endl; exit(1); } /*steps: * 1. load a long-type (4 float) into a v4sf type data from both arrays. * 2. multiply the two. * 3. multiply the same and store result. * 4. add this to previous results. */ v4sf arr1Data, arr2Data, prevSums, multVal, xyz; //__builtin_ia32_xorps(prevSums, prevSums); //making it equal zero. //can explicitly load 0 into prevSums using loadps or storeps (Check). float temp[4] = {0.0, 0.0, 0.0, 0.0}; prevSums = __builtin_ia32_loadups(temp); float result = 0.0; for(int i = 0; i < (len1 - 3); i += 4) { for(int j = 0; j < len1; j++) { arr1Data = __builtin_ia32_loadups(&arr1[i]); arr2Data = __builtin_ia32_loadups(&arr2[i]); //store the contents of two arrays. multVal = __builtin_ia32_mulps(arr1Data, arr2Data); //multiply. xyz = __builtin_ia32_addps(multVal, prevSums); prevSums = xyz; } } //prevSums will hold the sums of 4 32-bit floating point values taken at a time. Individual entries in prevSums also need to be added. __builtin_ia32_storeups(temp, prevSums); //store prevSums into temp. cout << "Values of temp:" << endl; for(int i = 0; i < 4; i++) cout << temp[i] << endl; result += temp[0] + temp[1] + temp[2] + temp[3]; return result; } int main() { clock_t begin, end; int length = 100000; float *arr1, *arr2; double result_Conventional, result_Intrinsic; // printStats("Allocating memory."); arr1 = new float[length]; arr2 = new float[length]; // printStats("End allocation."); srand(time(NULL)); //init random seed. // printStats("Initializing array1 and array2"); begin = clock(); for(int i = 0; i < length; i++) { // for(int j = 0; j < length; j++) { // arr1[i] = rand() % 10 + 1; arr1[i] = 2.5; // arr2[i] = rand() % 10 - 1; arr2[i] = 2.5; // } } end = clock(); cout << "Time to initialize array1 and array2 = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("Finished initialization."); // printStats("Begin inner product conventionally."); begin = clock(); result_Conventional = innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product conventionally = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; // printStats("End inner product conventionally."); // printStats("Begin inner product using Intrinsics."); begin = clock(); result_Intrinsic = sse_v4sf_innerProduct(arr1, length, arr2, length); end = clock(); cout << "Time to compute inner product with intrinsics = " << ((double) (end - begin)) / CLOCKS_PER_SEC << endl; //printStats("End inner product using Intrinsics."); cout << "Results: " << endl; cout << " result_Conventional = " << result_Conventional << endl; cout << " result_Intrinsics = " << result_Intrinsic << endl; return 0; } I use the following g++ invocation to build this: g++ -W -Wall -O2 -pedantic -march=i386 -msse intrinsics_SSE_innerProduct.C -o innerProduct Each of the loops above, in both the functions, runs a total of N^2 times. However, given that arr1 and arr2 (the two floating point vectors) are loaded with a value 2.5, the length of the array is 100,000, the result in both cases should be 6.25e+10. The results I get are: Results: result_Conventional = 6.25e+10 result_Intrinsics = 5.36871e+08 This is not all. It seems that the value returned from the function that uses intrinsics "saturates" at the value above. I tried putting other values for the elements of the array and different sizes too. But it seems that any value above 1.0 for the array contents and any size above 1000 meets with the same value we see above. Initially, I thought it might be because all operations within SSE are in floating point, but floating point should be able to store a number that is of the order of e+08. I am trying to see where I could be going wrong but cannot seem to figure it out. I am using g++ version: g++ (GCC) 4.4.1 20090725 (Red Hat 4.4.1-2). Any help on this is most welcome. Thanks, Sriram.

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  • Form File Upload with other TextBox Inputs + Creating Custom Form Action attribute

    - by Jonathan Stowell
    Hi All, I am attempting to create a form where a user is able to enter your typical form values textboxes etc, but also upload a file as part of the form submission. This is my View code it can be seen that the File upload is identified by the MCF id: <% using (Html.BeginForm("Create", "Problem", FormMethod.Post, new { id = "ProblemForm", enctype = "multipart/form-data" })) {%> <p> <label for="StudentEmail">Student Email (*)</label> <br /> <%= Html.TextBox("StudentEmail", Model.Problem.StudentEmail, new { size = "30", maxlength=26 })%> <%= Html.ValidationMessage("StudentEmail", "*") %> </p> <p> <label for="Type">Communication Type (*)</label> <br /> <%= Html.DropDownList("Type") %> <%= Html.ValidationMessage("Type", "*") %> </p> <p> <label for="ProblemDateTime">Problem Date (*)</label> <br /> <%= Html.TextBox("ProblemDateTime", String.Format("{0:d}", Model.Problem.ProblemDateTime), new { maxlength = 10 })%> <%= Html.ValidationMessage("ProblemDateTime", "*") %> </p> <p> <label for="ProblemCategory">Problem Category (* OR Problem Outline)</label> <br /> <%= Html.DropDownList("ProblemCategory", null, "Please Select...")%> <%= Html.ValidationMessage("ProblemCategory", "*")%> </p> <p> <label for="ProblemOutline">Problem Outline (* OR Problem Category)</label> <br /> <%= Html.TextArea("ProblemOutline", Model.Problem.ProblemOutline, 6, 75, new { maxlength = 255 })%> <%= Html.ValidationMessage("ProblemOutline", "*") %> </p> <p> <label for="MCF">Mitigating Circumstance Form</label> <br /> <input id="MCF" type="file" /> <%= Html.ValidationMessage("MCF", "*") %> </p> <p> <label for="MCL">Mitigating Circumstance Level</label> <br /> <%= Html.DropDownList("MCL") %> <%= Html.ValidationMessage("MCL", "*") %> </p> <p> <label for="AbsentFrom">Date Absent From</label> <br /> <%= Html.TextBox("AbsentFrom", String.Format("{0:d}", Model.Problem.AbsentFrom), new { maxlength = 10 })%> <%= Html.ValidationMessage("AbsentFrom", "*") %> </p> <p> <label for="AbsentUntil">Date Absent Until</label> <br /> <%= Html.TextBox("AbsentUntil", String.Format("{0:d}", Model.Problem.AbsentUntil), new { maxlength = 10 })%> <%= Html.ValidationMessage("AbsentUntil", "*") %> </p> <p> <label for="AssessmentID">Assessment Extension</label> <br /> <%= Html.DropDownList("AssessmentID") %> <%= Html.ValidationMessage("AssessmentID", "*") %> <%= Html.TextBox("DateUntil", String.Format("{0:d}", Model.AssessmentExtension.DateUntil), new { maxlength = 16 })%> <%= Html.ValidationMessage("DateUntil", "*") %> </p> <p> <label for="Details">Assessment Extension Details</label> <br /> <%= Html.TextArea("Details", Model.AssessmentExtension.Details, 6, 75, new { maxlength = 255 })%> <%= Html.ValidationMessage("Details", "*") %> </p> <p> <label for="RequestedFollowUp">Requested Follow Up</label> <br /> <%= Html.TextBox("RequestedFollowUp", String.Format("{0:d}", Model.Problem.RequestedFollowUp), new { maxlength = 16 })%> <%= Html.ValidationMessage("RequestedFollowUp", "*") %> </p> <p> <label for="StaffEmail">Staff</label> <br /> <%= Html.ListBox("StaffEmail", Model.StaffEmail, new { @class = "multiselect" })%> <%= Html.ValidationMessage("StaffEmail", "*")%> </p> <p> <input class="button" type="submit" value="Create Problem" /> </p> This is my controller code: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Create(Problem problem, AssessmentExtension assessmentExtension, Staff staffMember, HttpPostedFileBase file, string[] StaffEmail) { if (ModelState.IsValid) { try { Student student = studentRepository.GetStudent(problem.StudentEmail); Staff currentUserStaffMember = staffRepository.GetStaffWindowsLogon(User.Identity.Name); var fileName = Path.Combine(Request.MapPath("~/App_Data"), Path.GetFileName(file.FileName)); file.SaveAs(@"C:\Temp\" + fileName); if (problem.RequestedFollowUp.HasValue) { String meetingName = student.FirstName + " " + student.LastName + " " + "Mitigating Circumstance Meeting"; OutlookAppointment outlookAppointment = new OutlookAppointment(currentUserStaffMember.Email, meetingName, (DateTime)problem.RequestedFollowUp, (DateTime)problem.RequestedFollowUp.Value.AddMinutes(30)); } problemRepository.Add(problem); problemRepository.Save(); if (assessmentExtension.DateUntil != null) { assessmentExtension.ProblemID = problem.ProblemID; assessmentExtensionRepository.Add(assessmentExtension); assessmentExtensionRepository.Save(); } ProblemPrivacy problemPrivacy = new ProblemPrivacy(); problemPrivacy.ProblemID = problem.ProblemID; problemPrivacy.StaffEmail = currentUserStaffMember.Email; problemPrivacyRepository.Add(problemPrivacy); if (StaffEmail != null) { for (int i = 0; i < StaffEmail.Length; i++) { ProblemPrivacy probPrivacy = new ProblemPrivacy(); probPrivacy.ProblemID = problem.ProblemID; probPrivacy.StaffEmail = StaffEmail[i]; problemPrivacyRepository.Add(probPrivacy); } } problemPrivacyRepository.Save(); return RedirectToAction("Details", "Student", new { id = student.Email }); } catch { ModelState.AddRuleViolations(problem.GetRuleViolations()); } } return View(new ProblemFormViewModel(problem, assessmentExtension, staffMember)); } This form was working correctly before I had to switch to using a non-AJAX file upload, this was due to an issue with Flash when enabling Windows Authentication which I need to use. It appears that when I submit the form the file is not sent and I am unsure as to why? I have also been unsuccessful in finding an example online where a file upload is used in conjunction with other input types. Another query I have is that for Create, and Edit operations I have used a PartialView for my forms to make my application have higher code reuse. The form action is normally generated by just using: Html.BeginForm() And this populates the action depending on which Url is being used Edit or Create. However when populating HTML attributes you have to provide a action and controller value to pass HTML attributes. using (Html.BeginForm("Create", "Problem", FormMethod.Post, new { id = "ProblemForm", enctype = "multipart/form-data" })) Is it possible to somehow populate the action and controller value depending on the URL to maintain code reuse? Thinking about it whilst typing this I could set two values in the original controller action request view data and then just populate the value using the viewdata values? Any help on these two issues would be appreciated, I'm new to asp.net mvc :-) Thanks, Jon

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  • Why does C qicksort function implementation works much slower (tape comparations, tape swapping) than bobble sort function?

    - by Artur Mustafin
    I'm going to implement a toy tape "mainframe" for a students, showing the quickness of "quicksort" class functions (recursive or not, does not really matters, due to the slow hardware, and well known stack reversal techniques) comparatively to the "bubblesort" function class, so, while I'm clear about the hardware implementation ans controllers, i guessed that quicksort function is much faster that other ones in terms of sequence, order and comparation distance (it is much faster to rewind the tape from the middle than from the very end, because of different speed of rewind). Unfortunately, this is not the true, this simple "bubble" code shows great improvements comparatively to the "quicksort" functions in terms of comparison distances, direction and number of comparisons and writes. So I have 3 questions: Does I have mistaken in my implememtation of quicksort function? Does I have mistaken in my implememtation of bubblesoft function? If not, why the "bubblesort" function is works much faster in (comparison and write operations) than "quicksort" function? I already have a "quicksort" function: void quicksort(float *a, long l, long r, const compare_function& compare) { long i=l, j=r, temp, m=(l+r)/2; if (l == r) return; if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while (1) { i = l; j = r; while (i < m && !compare(a, i, m)) i++; while (m < j && !compare(a, m, j)) j--; if (i >= j) { break; } swap(a, i, j); } if (l < m) quicksort(a, l, m, compare); if (m < r) quicksort(a, m, r, compare); return; } } and the kind of my own implememtation of the "bubblesort" function: void bubblesort(float *a, long l, long r, const compare_function& compare) { long i, j, k; if (l == r) { return; } if (l == r-1) { if (compare(a, l, r)) { swap(a, l, r); } return; } if (l < r-1) { while(l < r) { i = l; j = l; while (i < r) { i++; if (!compare(a, j, i)) { continue; } j = i; } if (l < j) { swap(a, l, j); } l++; i = r; k = r; while(l < i) { i--; if (!compare(a, i, k)) { continue; } k = i; } if (k < r) { swap(a, k, r); } r--; } return; } } I have used this sort functions in a test sample code, like this: #include <stdio.h> #include <stdlib.h> #include <math.h> #include <conio.h> long swap_count; long compare_count; typedef long (*compare_function)(float *, long, long ); typedef void (*sort_function)(float *, long , long , const compare_function& ); void init(float *, long ); void print(float *, long ); void sort(float *, long, const sort_function& ); void swap(float *a, long l, long r); long less(float *a, long l, long r); long greater(float *a, long l, long r); void bubblesort(float *, long , long , const compare_function& ); void quicksort(float *, long , long , const compare_function& ); void main() { int n; printf("n="); scanf("%d",&n); printf("\r\n"); long i; float *a = (float *)malloc(n*n*sizeof(float)); sort(a, n, &bubblesort); print(a, n); sort(a, n, &quicksort); print(a, n); free(a); } long less(float *a, long l, long r) { compare_count++; return *(a+l) < *(a+r) ? 1 : 0; } long greater(float *a, long l, long r) { compare_count++; return *(a+l) > *(a+r) ? 1 : 0; } void swap(float *a, long l, long r) { swap_count++; float temp; temp = *(a+l); *(a+l) = *(a+r); *(a+r) = temp; } float tg(float x) { return tan(x); } float ctg(float x) { return 1.0/tan(x); } void init(float *m,long n) { long i,j; for (i = 0; i < n; i++) { for (j=0; j< n; j++) { m[i + j*n] = tg(0.2*(i+1)) + ctg(0.3*(j+1)); } } } void print(float *m, long n) { long i, j; for(i = 0; i < n; i++) { for(j = 0; j < n; j++) { printf(" %5.1f", m[i + j*n]); } printf("\r\n"); } printf("\r\n"); } void sort(float *a, long n, const sort_function& sort) { long i, sort_compare = 0, sort_swap = 0; init(a,n); for(i = 0; i < n*n; i+=n) { if (fmod (i / n, 2) == 0) { compare_count = 0; swap_count = 0; sort(a, i, i+n-1, &less); if (swap_count == 0) { compare_count = 0; sort(a, i, i+n-1, &greater); } sort_compare += compare_count; sort_swap += swap_count; } } printf("compare=%ld\r\n", sort_compare); printf("swap=%ld\r\n", sort_swap); printf("\r\n"); }

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  • Help with java GUI- has error in main thread

    - by jan
    Hello guys, Basically im trying to do a Insurance Application form in java. And it uses multiple JPanels in a JFrame. -adding of JPanel into main program frame was done like this: //jpCenterArea to hold jp1-jp7 jpCenterArea.add(jp1); jpCenterArea.add(jp2); jpCenterArea.add(jp3); jpCenterArea.add(jp4); ...etc ********Add Jpanels to JFrame*****/ add(jpTitle, BorderLayout.NORTH); add(jpCenterArea, BorderLayout.CENTER); add(jpBottom, BorderLayout.SOUTH); However, even though program can compile, it cannot be run. error as mentioned below: Exception in thread "main" java.lang.NullPointerException at java.awt.Container.addImpl<Container.java:1045> at java.awt.Container.add<Container.java:365> at TravelInsuranceApplication.<init>TravelInsuranceApplication.java:120> at TravelInsuranceApplication.main<TravelInsuranceApplication.java:154> 1 import javax.swing.*; 2 import java.awt.*; 3 public class TravelInsuranceApplication extends JFrame 4 { 5 //declare private variables 6 private JLabel jlblTitle, jlblName, jlblNRIC, jlblAdd, jlblPostal, jlblContact, jlblDOB, 7 jlblEmail, jlblPeriod; 8 private JLabel jlblDeparture, jlblDays, jlblZone, jlblPlan; 9 private JTextField jtfName, jtfIC, jtfAdd, jtfPostal, jtfContact, jtfEmail, jtfZone; 10 private JRadioButton jrbResident, jrbOffice, jrbDeluxe, jrbClassic, jrbAsia, jrbWorldwide; 11 private ButtonGroup bgContact, bgZone, bgPlan; 12 private JComboBox jcDay, jcMonth, jcYear; 13 private JButton jbtnSubmit, jbtnCalculate, jbtnClear; 14 private JPanel jpTitle,jp1, jp2, jp3, jp4, jp5, jp6, jp7, jpBottom, jpCenterArea; 15 String[] day = {"1", "2", "3"}; 16 String[] month = {"january", "february"}; 17 String[] year = {"1981", "1985", "1990", "1995"}; 18 19 //constructor and GUI development 20 public TravelInsuranceApplication() 21 { 22 setSize(500,200); 23 setTitle("Travel Insurance Application"); 24 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 25 setLayout(new BorderLayout()); 26 27 //create ALL component objects/ 28 jlblTitle = new JLabel("Travel Insurance Application: "); 29 jlblName = new JLabel("Name of Insured: "); 30 jlblNRIC = new JLabel("NRIC: "); 31 jlblAdd = new JLabel("Address: "); 32 jlblPostal = new JLabel("Postal Code: "); 33 jlblContact = new JLabel("Telephone: "); 34 jlblDOB = new JLabel("Date Of Birth: "); 35 jlblEmail = new JLabel("Email Address: "); 36 jlblPeriod = new JLabel("Period Of Insurance "); 37 jlblDeparture = new JLabel("Departure Date "); 38 jlblDays = new JLabel("How Many Days To Insure "); 39 jlblZone = new JLabel("Zone: "); 40 jlblPlan = new JLabel("Plan: "); 41 42 jtfName = new JTextField(50); 43 jtfIC = new JTextField(15); 44 jtfAdd = new JTextField(50); 45 jtfPostal = new JTextField(15); 46 jtfContact = new JTextField(15); 47 jtfEmail = new JTextField(50); 48 jtfZone = new JTextField(100); 49 50 jrbResident = new JRadioButton("Rseident/Pgr"); 51 jrbOffice = new JRadioButton("Office/HP"); 52 jrbAsia = new JRadioButton("Asia"); 53 jrbAsia = new JRadioButton("Worldwide"); 54 jrbDeluxe = new JRadioButton("Deluxe"); 55 jrbClassic = new JRadioButton("Classic"); 56 57 jcDay = new JComboBox(day); 58 jcMonth = new JComboBox(month); 59 jcYear = new JComboBox(year); 60 61 jbtnSubmit = new JButton("Submit"); 62 jbtnCalculate = new JButton("Calculate"); 63 jbtnClear = new JButton("Clear"); 64 65 /****create JPanels - jpTitle, JpCenterArea & jp2-jp8 , jpBottom + setLayout 66 for ALL JPanels******/ 67 jpTitle = new JPanel(new FlowLayout(FlowLayout.CENTER)); 68 jpCenterArea = new JPanel(new FlowLayout()); 69 jp1 = new JPanel(new FlowLayout()); 70 jp2 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 71 jp3 = new JPanel(new FlowLayout()); 72 jp4 = new JPanel(new FlowLayout()); 73 jp5 = new JPanel(new FlowLayout()); 74 jp6 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 75 jp7 = new JPanel(new FlowLayout(FlowLayout.CENTER)); 76 jpBottom = new JPanel(new FlowLayout(FlowLayout.CENTER)); 77 78 79 80 81 //add components to JPanels 82 jpTitle.add(jlblTitle); 83 84 //jp1 85 jp1.add(jlblName); 86 jp1.add(jtfName); 87 jp1.add(jlblNRIC); 88 jp1.add(jtfIC); 89 90 //jp2 91 jp2.add(jlblAdd); 92 jp2.add(jtfAdd); 93 jp2.add(jlblPostal); 94 jp2.add(jtfPostal); 95 96 //jp3 97 jp3.add(jlblContact); 98 jp3.add(jtfContact); 99 jp3.add(jrbResident); 100 jp3.add(jrbOffice); 101 jp3.add(jlblDOB); 102 jp3.add(jcDay); 103 jp3.add(jcMonth); 104 jp3.add(jcYear); 105 106 //jp4 107 jp4.add(jlblEmail); 108 jp4.add(jtfEmail); 109 110 //jp5 111 jp5.add(jlblPeriod); 112 jp5.add(jlblDeparture); 113 jp5.add(jcDay); 114 jp5.add(jcMonth); 115 jp5.add(jcYear); 116 jp5.add(jlblDays); 117 jp5.add(jcDay); 118 119 //jp6 120 jp6.add(jlblZone); 121 jp6.add(jrbAsia); 122 jp6.add(jrbWorldwide); 123 jp6.add(jlblPlan); 124 jp6.add(jrbDeluxe); 125 jp6.add(jrbClassic); 126 127 //jp7 128 jp7.add(jtfZone); 129 130 //jpCenterArea to hold jp1-jp7 131 jpCenterArea.add(jp1); 132 jpCenterArea.add(jp2); 133 jpCenterArea.add(jp3); 134 jpCenterArea.add(jp4); 135 jpCenterArea.add(jp5); 136 jpCenterArea.add(jp6); 137 jpCenterArea.add(jp7); 138 139 //jpBottom 140 jpBottom.add(jbtnSubmit); 141 jpBottom.add(jbtnCalculate); 142 jpBottom.add(jbtnClear); 143 144 /********Add Jpanels to JFrame*****/ 145 add(jpTitle, BorderLayout.NORTH); 146 add(jpCenterArea, BorderLayout.CENTER); 147 add(jpBottom, BorderLayout.SOUTH); 148 149 setVisible(true); 150 151 152 153 }//end null constructor 154 public static void main(String[] args) 155 { 156 TravelInsuranceApplication travel = new TravelInsuranceApplication(); 157 158 }//end main 159 160 }//end class

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  • Using Handlebars.js issue

    - by Roland
    I'm having a small issue when I'm compiling a template with Handlebars.js . I have a JSON text file which contains an big array with objects : Source ; and I'm using XMLHTTPRequest to get it and then parse it so I can use it when compiling the template. So far the template has the following structure : <div class="product-listing-wrapper"> <div class="product-listing"> <div class="left-side-content"> <div class="thumb-wrapper"> <img src="{{ThumbnailUrl}}"> </div> <div class="google-maps-wrapper"> <div class="google-coordonates-wrapper"> <div class="google-coordonates"> <p>{{LatLon.Lat}}</p> <p>{{LatLon.Lon}}</p> </div> </div> <div class="google-maps-button"> <a class="google-maps" href="#" data-latitude="{{LatLon.Lat}}" data-longitude="{{LatLon.Lon}}">Google Maps</a> </div> </div> </div> <div class="right-side-content"></div> </div> And the following block of code would be the way I'm handling the JS part : $(document).ready(function() { /* Default Javascript Options ~a javascript object which contains all the variables that will be passed to the cluster class */ var default_cluster_options = { animations : ['flash', 'bounce', 'shake', 'tada', 'swing', 'wobble', 'wiggle', 'pulse', 'flip', 'flipInX', 'flipOutX', 'flipInY', 'flipOutY', 'fadeIn', 'fadeInUp', 'fadeInDown', 'fadeInLeft', 'fadeInRight', 'fadeInUpBig', 'fadeInDownBig', 'fadeInLeftBig', 'fadeInRightBig', 'fadeOut', 'fadeOutUp', 'fadeOutDown', 'fadeOutLeft', 'fadeOutRight', 'fadeOutUpBig', 'fadeOutDownBig', 'fadeOutLeftBig', 'fadeOutRightBig', 'bounceIn', 'bounceInUp', 'bounceInDown', 'bounceInLeft', 'bounceInRight', 'bounceOut', 'bounceOutUp', 'bounceOutDown', 'bounceOutLeft', 'bounceOutRight', 'rotateIn', 'rotateInDownLeft', 'rotateInDownRight', 'rotateInUpLeft', 'rotateInUpRight', 'rotateOut', 'rotateOutDownLeft', 'rotateOutDownRight', 'rotateOutUpLeft', 'rotateOutUpRight', 'lightSpeedIn', 'lightSpeedOut', 'hinge', 'rollIn', 'rollOut'], json_data_url : 'data.json', template_data_url : 'template.php', base_maps_api_url : 'https://maps.googleapis.com/maps/api/js?sensor=false', cluser_wrapper_id : '#content-wrapper', maps_wrapper_class : '.google-maps', }; /* Cluster ~main class, handles all javascript operations */ var Cluster = function(environment, cluster_options) { var self = this; this.options = $.extend({}, default_cluster_options, cluster_options); this.environment = environment; this.animations = this.options.animations; this.json_data_url = this.options.json_data_url; this.template_data_url = this.options.template_data_url; this.base_maps_api_url = this.options.base_maps_api_url; this.cluser_wrapper_id = this.options.cluser_wrapper_id; this.maps_wrapper_class = this.options.maps_wrapper_class; this.test_environment_mode(this.environment); this.initiate_environment(); this.test_xmlhttprequest_availability(); this.initiate_gmaps_lib_load(self.base_maps_api_url); this.initiate_data_processing(); }; /* Test Environment Mode ~adds a modernizr test which looks wheater the cluster class is initiated in development or not */ Cluster.prototype.test_environment_mode = function(environment) { var self = this; return Modernizr.addTest('test_environment', function() { return (typeof environment !== 'undefined' && environment !== null && environment === "Development") ? true : false; }); }; /* Test XMLHTTPRequest Availability ~adds a modernizr test which looks wheater the xmlhttprequest class is available or not in the browser, exception makes IE */ Cluster.prototype.test_xmlhttprequest_availability = function() { return Modernizr.addTest('test_xmlhttprequest', function() { return (typeof window.XMLHttpRequest === 'undefined' || window.XMLHttpRequest === null) ? true : false; }); }; /* Initiate Environment ~depending on what the modernizr test returns it puts LESS in the development mode or not */ Cluster.prototype.initiate_environment = function() { return (Modernizr.test_environment) ? (less.env = "development", less.watch()) : true; }; Cluster.prototype.initiate_gmaps_lib_load = function(lib_url) { return Modernizr.load(lib_url); }; /* Initiate XHR Request ~prototype function that creates an xmlhttprequest for processing json data from an separate json text file */ Cluster.prototype.initiate_xhr_request = function(url, mime_type) { var request, data; var self = this; (Modernizr.test_xmlhttprequest) ? request = new ActiveXObject('Microsoft.XMLHTTP') : request = new XMLHttpRequest(); request.onreadystatechange = function() { if(request.readyState == 4 && request.status == 200) { data = request.responseText; } }; request.open("GET", url, false); request.overrideMimeType(mime_type); request.send(); return data; }; Cluster.prototype.initiate_google_maps_action = function() { var self = this; return $(this.maps_wrapper_class).each(function(index, element) { return $(element).on('click', function(ev) { var html = $('<div id="map-canvas" class="map-canvas"></div>'); var latitude = $(element).attr('data-latitude'); var longitude = $(element).attr('data-longitude'); log("LAT : " + latitude); log("LON : " + longitude); $.lightbox(html, { "width": 900, "height": 250, "onOpen" : function() { } }); ev.preventDefault(); }); }); }; Cluster.prototype.initiate_data_processing = function() { var self = this; var json_data = JSON.parse(self.initiate_xhr_request(self.json_data_url, 'application/json; charset=ISO-8859-1')); var source_data = self.initiate_xhr_request(self.template_data_url, 'text/html'); var template = Handlebars.compile(source_data); for(var i = 0; i < json_data.length; i++ ) { var result = template(json_data[i]); $(result).appendTo(self.cluser_wrapper_id); } self.initiate_google_maps_action(); }; /* Cluster ~initiate the cluster class */ var cluster = new Cluster("Development"); }); My problem would be that I don't think I'm iterating the JSON object right or I'm using the template the wrong way because if you check this link : http://rolandgroza.com/labs/valtech/ ; you will see that there are some numbers there ( which represents latitude and longitude ) but they are all the same and if you take only a brief look at the JSON object each number is different. So what am I doing wrong that it makes the same number repeat ? Or what should I do to fix it ? I must notice that I've just started working with templates so I have little knowledge it.

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  • c# Unable to open file for reading

    - by Maks
    I'm writing a program that uses FileSystemWatcher to monitor changes to a given directory, and when it recieves OnCreated or OnChanged event, it copies those created/changed files to a specified directorie(s). At first I had problems with the fact that OnChanged/OnCreated events can be sent twice (not acceptable in case it needed to process 500MB file) but I made a way around this and with what I'm REALLY STUCKED with is getting the following IOException: The process cannot access the file 'C:\Where are Photos\bookmarks (11).html' because it is being used by another process. Thus, preventing the program from copying all the files it should. So as I mentioned, when user uses this program he/she specifes monitored directory, when user copies/creates/changes file in that directory, program should get OnCreated/OnChanged event and then copy that file to few other directories. Above error happens in all casess, if user copies few files that needs to owerwrite other ones in folder being monitored or when copying bulk of several files or even sometimes when copying one file in a monitored directory. Whole program is quite big so I'm sending the most important parts. OnCreated: private void OnCreated(object source, FileSystemEventArgs e) { AddLogEntry(e.FullPath, "created", ""); // Update last access data if it's file so the same file doesn't // get processed twice because of sending another event. if (fileType(e.FullPath) == 2) { lastPath = e.FullPath; lastTime = DateTime.Now; } // serves no purpose now, it will be remove soon string fileName = GetFileName(e.FullPath); // copies file from source to few other directories Copy(e.FullPath, fileName); Console.WriteLine("OnCreated: " + e.FullPath); } OnChanged: private void OnChanged(object source, FileSystemEventArgs e) { // is it directory if (fileType(e.FullPath) == 1) return; // don't mind directory changes itself // Only if enough time has passed or if it's some other file // because two events can be generated int timeDiff = ((TimeSpan)(DateTime.Now - lastTime)).Seconds; if ((timeDiff < minSecsDiff) && (e.FullPath.Equals(lastPath))) { Console.WriteLine("-- skipped -- {0}, timediff: {1}", e.FullPath, timeDiff); return; } // Update last access data for above to work lastPath = e.FullPath; lastTime = DateTime.Now; // Only if size is changed, the rest will handle other handlers if (e.ChangeType == WatcherChangeTypes.Changed) { AddLogEntry(e.FullPath, "changed", ""); string fileName = GetFileName(e.FullPath); Copy(e.FullPath, fileName); Console.WriteLine("OnChanged: " + e.FullPath); } } fileType: private int fileType(string path) { if (Directory.Exists(path)) return 1; // directory else if (File.Exists(path)) return 2; // file else return 0; } Copy: private void Copy(string srcPath, string fileName) { foreach (string dstDirectoy in paths) { string eventType = "copied"; string error = "noerror"; string path = ""; string dirPortion = ""; // in case directory needs to be made if (srcPath.Length > fsw.Path.Length) { path = srcPath.Substring(fsw.Path.Length, srcPath.Length - fsw.Path.Length); int pos = path.LastIndexOf('\\'); if (pos != -1) dirPortion = path.Substring(0, pos); } if (fileType(srcPath) == 1) { try { Directory.CreateDirectory(dstDirectoy + path); //Directory.CreateDirectory(dstDirectoy + fileName); eventType = "created"; } catch (IOException e) { eventType = "error"; error = e.Message; } } else { try { if (!overwriteFile && File.Exists(dstDirectoy + path)) continue; // create new dir anyway even if it exists just to be sure Directory.CreateDirectory(dstDirectoy + dirPortion); // copy file from where event occured to all specified directories using (FileStream fsin = new FileStream(srcPath, FileMode.Open, FileAccess.Read, FileShare.Read)) { using (FileStream fsout = new FileStream(dstDirectoy + path, FileMode.Create, FileAccess.Write)) { byte[] buffer = new byte[32768]; int bytesRead = -1; while ((bytesRead = fsin.Read(buffer, 0, buffer.Length)) > 0) fsout.Write(buffer, 0, bytesRead); } } } catch (Exception e) { if ((e is IOException) && (overwriteFile == false)) { eventType = "skipped"; } else { eventType = "error"; error = e.Message; // attempt to find and kill the process locking the file. // failed, miserably System.Diagnostics.Process tool = new System.Diagnostics.Process(); tool.StartInfo.FileName = "handle.exe"; tool.StartInfo.Arguments = "\"" + srcPath + "\""; tool.StartInfo.UseShellExecute = false; tool.StartInfo.RedirectStandardOutput = true; tool.Start(); tool.WaitForExit(); string outputTool = tool.StandardOutput.ReadToEnd(); string matchPattern = @"(?<=\s+pid:\s+)\b(\d+)\b(?=\s+)"; foreach (Match match in Regex.Matches(outputTool, matchPattern)) { System.Diagnostics.Process.GetProcessById(int.Parse(match.Value)).Kill(); } Console.WriteLine("ERROR: {0}: [ {1} ]", e.Message, srcPath); } } } AddLogEntry(dstDirectoy + path, eventType, error); } } I checked everywhere in my program and whenever I use some file I use it in using block so even writing event to log (class for what I ommited since there is probably too much code already in post) wont lock the file, that is it shouldn't since all operations are using using statement block. I simply have no clue who's locking the file if not my program "copy" process from user through Windows or something else. Right now I have two possible "solutions" (I can't say they are clean solutions since they are hacks and as such not desireable). Since probably the problem is with fileType method (what else could lock the file?) I tried changing it to this, to simulate "blocking-until-ready-to-open" operation: fileType: private int fileType(string path) { FileStream fs = null; int ret = 0; bool run = true; if (Directory.Exists(path)) ret = 1; else { while (run) { try { fs = new FileStream(path, FileMode.Open); ret = 2; run = false; } catch (IOException) { } finally { if (fs != null) { fs.Close(); fs.Dispose(); } } } } return ret; } This is working as much as I could tell (test), but... it's hack, not to mention other deficients. The other "solution" I could try (I didn't test it yet) is using GC.Collect() somewhere at the end of fileType() method. Maybe even worse "solution" than previous one. Can someone pleas tell me, what on earth is locking the file, preventing it from opening and how can I fix that? What am I missing to see? Thanks in advance.

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  • Linked List manipulation, issues retrieving data c++

    - by floatfil
    I'm trying to implement some functions to manipulate a linked list. The implementation is a template typename T and the class is 'List' which includes a 'head' pointer and also a struct: struct Node { // the node in a linked list T* data; // pointer to actual data, operations in T Node* next; // pointer to a Node }; Since it is a template, and 'T' can be any data, how do I go about checking the data of a list to see if it matches the data input into the function? The function is called 'retrieve' and takes two parameters, the data and a pointer: bool retrieve(T target, T*& ptr); // This is the prototype we need to use for the project "bool retrieve : similar to remove, but not removed from list. If there are duplicates in the list, the first one encountered is retrieved. Second parameter is unreliable if return value is false. E.g., " Employee target("duck", "donald"); success = company1.retrieve(target, oneEmployee); if (success) { cout << "Found in list: " << *oneEmployee << endl; } And the function is called like this: company4.retrieve(emp3, oneEmployee) So that when you cout *oneEmployee, you'll get the data of that pointer (in this case the data is of type Employee). (Also, this is assuming all data types have the apropriate overloaded operators) I hope this makes sense so far, but my issue is in comparing the data in the parameter and the data while going through the list. (The data types that we use all include overloads for equality operators, so oneData == twoData is valid) This is what I have so far: template <typename T> bool List<T>::retrieve(T target , T*& ptr) { List<T>::Node* dummyPtr = head; // point dummy pointer to what the list's head points to for(;;) { if (*dummyPtr->data == target) { // EDIT: it now compiles, but it breaks here and I get an Access Violation error. ptr = dummyPtr->data; // set the parameter pointer to the dummy pointer return true; // return true } else { dummyPtr = dummyPtr->next; // else, move to the next data node } } return false; } Here is the implementation for the Employee class: //-------------------------- constructor ----------------------------------- Employee::Employee(string last, string first, int id, int sal) { idNumber = (id >= 0 && id <= MAXID? id : -1); salary = (sal >= 0 ? sal : -1); lastName = last; firstName = first; } //-------------------------- destructor ------------------------------------ // Needed so that memory for strings is properly deallocated Employee::~Employee() { } //---------------------- copy constructor ----------------------------------- Employee::Employee(const Employee& E) { lastName = E.lastName; firstName = E.firstName; idNumber = E.idNumber; salary = E.salary; } //-------------------------- operator= --------------------------------------- Employee& Employee::operator=(const Employee& E) { if (&E != this) { idNumber = E.idNumber; salary = E.salary; lastName = E.lastName; firstName = E.firstName; } return *this; } //----------------------------- setData ------------------------------------ // set data from file bool Employee::setData(ifstream& inFile) { inFile >> lastName >> firstName >> idNumber >> salary; return idNumber >= 0 && idNumber <= MAXID && salary >= 0; } //------------------------------- < ---------------------------------------- // < defined by value of name bool Employee::operator<(const Employee& E) const { return lastName < E.lastName || (lastName == E.lastName && firstName < E.firstName); } //------------------------------- <= ---------------------------------------- // < defined by value of inamedNumber bool Employee::operator<=(const Employee& E) const { return *this < E || *this == E; } //------------------------------- > ---------------------------------------- // > defined by value of name bool Employee::operator>(const Employee& E) const { return lastName > E.lastName || (lastName == E.lastName && firstName > E.firstName); } //------------------------------- >= ---------------------------------------- // < defined by value of name bool Employee::operator>=(const Employee& E) const { return *this > E || *this == E; } //----------------- operator == (equality) ---------------- // if name of calling and passed object are equal, // return true, otherwise false // bool Employee::operator==(const Employee& E) const { return lastName == E.lastName && firstName == E.firstName; } //----------------- operator != (inequality) ---------------- // return opposite value of operator== bool Employee::operator!=(const Employee& E) const { return !(*this == E); } //------------------------------- << --------------------------------------- // display Employee object ostream& operator<<(ostream& output, const Employee& E) { output << setw(4) << E.idNumber << setw(7) << E.salary << " " << E.lastName << " " << E.firstName << endl; return output; } I will include a check for NULL pointer but I just want to get this working and will test it on a list that includes the data I am checking. Thanks to whoever can help and as usual, this is for a course so I don't expect or want the answer, but any tips as to what might be going wrong will help immensely!

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  • An Introduction to jQuery Templates

    - by Stephen Walther
    The goal of this blog entry is to provide you with enough information to start working with jQuery Templates. jQuery Templates enable you to display and manipulate data in the browser. For example, you can use jQuery Templates to format and display a set of database records that you have retrieved with an Ajax call. jQuery Templates supports a number of powerful features such as template tags, template composition, and wrapped templates. I’ll concentrate on the features that I think that you will find most useful. In order to focus on the jQuery Templates feature itself, this blog entry is server technology agnostic. All the samples use HTML pages instead of ASP.NET pages. In a future blog entry, I’ll focus on using jQuery Templates with ASP.NET Web Forms and ASP.NET MVC (You can do some pretty powerful things when jQuery Templates are used on the client and ASP.NET is used on the server). Introduction to jQuery Templates The jQuery Templates plugin was developed by the Microsoft ASP.NET team in collaboration with the open-source jQuery team. While working at Microsoft, I wrote the original proposal for jQuery Templates, Dave Reed wrote the original code, and Boris Moore wrote the final code. The jQuery team – especially John Resig – was very involved in each step of the process. Both the jQuery community and ASP.NET communities were very active in providing feedback. jQuery Templates will be included in the jQuery core library (the jQuery.js library) when jQuery 1.5 is released. Until jQuery 1.5 is released, you can download the jQuery Templates plugin from the jQuery Source Code Repository or you can use jQuery Templates directly from the ASP.NET CDN. The documentation for jQuery Templates is already included with the official jQuery documentation at http://api.jQuery.com. The main entry for jQuery templates is located under the topic plugins/templates. A Basic Sample of jQuery Templates Let’s start with a really simple sample of using jQuery Templates. We’ll use the plugin to display a list of books stored in a JavaScript array. Here’s the complete code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head> <title>Intro</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html> When you open this page in a browser, a list of books is displayed: There are several things going on in this page which require explanation. First, notice that the page uses both the jQuery 1.4.4 and jQuery Templates libraries. Both libraries are retrieved from the ASP.NET CDN: <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> You can use the ASP.NET CDN for free (even for production websites). You can learn more about the files included on the ASP.NET CDN by visiting the ASP.NET CDN documentation page. Second, you should notice that the actual template is included in a script tag with a special MIME type: <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> This template is displayed for each of the books rendered by the template. The template displays a book picture, title, and price. Notice that the SCRIPT tag which wraps the template has a MIME type of text/x-jQuery-tmpl. Why is the template wrapped in a SCRIPT tag and why the strange MIME type? When a browser encounters a SCRIPT tag with an unknown MIME type, it ignores the content of the tag. This is the behavior that you want with a template. You don’t want a browser to attempt to parse the contents of a template because this might cause side effects. For example, the template above includes an <img> tag with a src attribute that points at “BookPictures/${picture}”. You don’t want the browser to attempt to load an image at the URL “BookPictures/${picture}”. Instead, you want to prevent the browser from processing the IMG tag until the ${picture} expression is replaced by with the actual name of an image by the jQuery Templates plugin. If you are not worried about browser side-effects then you can wrap a template inside any HTML tag that you please. For example, the following DIV tag would also work with the jQuery Templates plugin: <div id="bookTemplate" style="display:none"> <div> <h2>${title}</h2> price: ${formatPrice(price)} </div> </div> Notice that the DIV tag includes a style=”display:none” attribute to prevent the template from being displayed until the template is parsed by the jQuery Templates plugin. Third, notice that the expression ${…} is used to display the value of a JavaScript expression within a template. For example, the expression ${title} is used to display the value of the book title property. You can use any JavaScript function that you please within the ${…} expression. For example, in the template above, the book price is formatted with the help of the custom JavaScript formatPrice() function which is defined lower in the page. Fourth, and finally, the template is rendered with the help of the tmpl() method. The following statement selects the bookTemplate and renders an array of books using the bookTemplate. The results are appended to a DIV element named bookContainer by using the standard jQuery appendTo() method. $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); Using Template Tags Within a template, you can use any of the following template tags. {{tmpl}} – Used for template composition. See the section below. {{wrap}} – Used for wrapped templates. See the section below. {{each}} – Used to iterate through a collection. {{if}} – Used to conditionally display template content. {{else}} – Used with {{if}} to conditionally display template content. {{html}} – Used to display the value of an HTML expression without encoding the value. Using ${…} or {{= }} performs HTML encoding automatically. {{= }}-- Used in exactly the same way as ${…}. {{! }} – Used for displaying comments. The contents of a {{!...}} tag are ignored. For example, imagine that you want to display a list of blog entries. Each blog entry could, possibly, have an associated list of categories. The following page illustrates how you can use the { if}} and {{each}} template tags to conditionally display categories for each blog entry:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>each</title> <link href="1_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="blogPostContainer"></div> <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var blogPosts = [ { postTitle: "How to fix a sink plunger in 5 minutes", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Sinks", "Plumbing"] }, { postTitle: "How to remove a broken lightbulb", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Lightbulbs", "Electricity"] }, { postTitle: "New associate website", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna." } ]; // Render the blog posts $("#blogPostTemplate").tmpl(blogPosts).appendTo("#blogPostContainer"); </script> </body> </html> When this page is opened in a web browser, the following list of blog posts and categories is displayed: Notice that the first and second blog entries have associated categories but the third blog entry does not. The third blog entry is “Uncategorized”. The template used to render the blog entries and categories looks like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> Notice the special expression $value used within the {{each}} template tag. You can use $value to display the value of the current template item. In this case, $value is used to display the value of each category in the collection of categories. Template Composition When building a fancy page, you might want to build a template out of multiple templates. In other words, you might want to take advantage of template composition. For example, imagine that you want to display a list of products. Some of the products are being sold at their normal price and some of the products are on sale. In that case, you might want to use two different templates for displaying a product: a productTemplate and a productOnSaleTemplate. The following page illustrates how you can use the {{tmpl}} tag to build a template from multiple templates:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Composition</title> <link href="2_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContainer"> <h1>Products</h1> <div id="productListContainer"></div> <!-- Show list of products using composition --> <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script> <!-- Show product --> <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script> <!-- Show product on sale --> <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var products = [ { name: "Laptop", onSale: false }, { name: "Apples", onSale: true }, { name: "Comb", onSale: false } ]; $("#productListTemplate").tmpl(products).appendTo("#productListContainer"); </script> </div> </body> </html>   In the page above, the main template used to display the list of products looks like this: <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script>   If a product is on sale then the product is displayed with the productOnSaleTemplate (which includes an on sale image): <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script>   Otherwise, the product is displayed with the normal productTemplate (which does not include the on sale image): <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script>   You can pass a parameter to the {{tmpl}} tag. The parameter becomes the data passed to the template rendered by the {{tmpl}} tag. For example, in the previous section, we used the {{each}} template tag to display a list of categories for each blog entry like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script>   Another way to create this template is to use template composition like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{tmpl(categories) "#categoryTemplate"}} {{else}} Uncategorized {{/if}} </script> <script id="categoryTemplate" type="text/x-jQuery-tmpl"> <i>${$data}</i> &nbsp; </script>   Using the {{each}} tag or {{tmpl}} tag is largely a matter of personal preference. Wrapped Templates The {{wrap}} template tag enables you to take a chunk of HTML and transform the HTML into another chunk of HTML (think easy XSLT). When you use the {{wrap}} tag, you work with two templates. The first template contains the HTML being transformed and the second template includes the filter expressions for transforming the HTML. For example, you can use the {{wrap}} template tag to transform a chunk of HTML into an interactive tab strip: When you click any of the tabs, you see the corresponding content. This tab strip was created with the following page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Wrapped Templates</title> <style type="text/css"> body { font-family: Arial; background-color:black; } .tabs div { display:inline-block; border-bottom: 1px solid black; padding:4px; background-color:gray; cursor:pointer; } .tabs div.tabState_true { background-color:white; border-bottom:1px solid white; } .tabBody { border-top:1px solid white; padding:10px; background-color:white; min-height:400px; width:400px; } </style> </head> <body> <div id="tabsView"></div> <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script> <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Global for tracking selected tab var selectedTabIndex = 0; // Render the tab strip $("#tabsContent").tmpl().appendTo("#tabsView"); // When a tab is clicked, update the tab strip $("#tabsView") .delegate(".tabState_false", "click", function () { var templateItem = $.tmplItem(this); selectedTabIndex = $(this).index(); templateItem.update(); }); </script> </body> </html>   The “source” for the tab strip is contained in the following template: <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script>   The tab strip is created with a list of H3 elements (which represent each tab) and DIV elements (which represent the body of each tab). Notice that the HTML content is wrapped in the {{wrap}} template tag. This template tag points at the following tabsWrap template: <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> The tabs DIV contains all of the tabs. The {{each}} template tag is used to loop through each of the H3 elements from the source template and render a DIV tag that represents a particular tab. The template item html() method is used to filter content from the “source” HTML template. The html() method accepts a jQuery selector for its first parameter. The tabs are retrieved from the source template by using an h3 filter. The second parameter passed to the html() method – the textOnly parameter -- causes the filter to return the inner text of each h3 element. You can learn more about the html() method at the jQuery website (see the section on $item.html()). The tabBody DIV renders the body of the selected tab. Notice that the {{html}} template tag is used to display the tab body so that HTML content in the body won’t be HTML encoded. The html() method is used, once again, to grab all of the DIV elements from the source HTML template. The selectedTabIndex global variable is used to display the contents of the selected tab. Remote Templates A common feature request for jQuery templates is support for remote templates. Developers want to be able to separate templates into different files. Adding support for remote templates requires only a few lines of extra code (Dave Ward has a nice blog entry on this). For example, the following page uses a remote template from a file named BookTemplate.htm: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Remote Templates</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The remote template is retrieved (and rendered) with the following code: // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); });   This code uses the standard jQuery $.get() method to get the BookTemplate.htm file from the server with an Ajax request. After the BookTemplate.htm file is successfully retrieved, the $.tmpl() method is used to render an array of books with the template. Here’s what the BookTemplate.htm file looks like: <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> Notice that the template in the BooksTemplate.htm file is not wrapped by a SCRIPT element. There is no need to wrap the template in this case because there is no possibility that the template will get interpreted before you want it to be interpreted. If you plan to use the bookTemplate multiple times – for example, you are paging or sorting the books -- then you should compile the template into a function and cache the compiled template function. For example, the following page can be used to page through a list of 100 products (using iPhone style More paging). <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Caching</title> <link href="6_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <h1>Products</h1> <div id="productContainer"></div> <button id="more">More</button> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Globals var pageIndex = 0; // Create an array of products var products = []; for (var i = 0; i < 100; i++) { products.push({ name: "Product " + (i + 1) }); } // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); }); $("#more").click(function () { pageIndex++; renderProducts(); }); function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The ProductTemplate is retrieved from an external file named ProductTemplate.htm. This template is retrieved only once. Furthermore, it is compiled and cached with the help of the $.template() method: // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); });   The $.template() method compiles the HTML representation of the template into a JavaScript function and caches the template function with the name productTemplate. The cached template can be used by calling the $.tmp() method. The productTemplate is used in the renderProducts() method: function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } In the code above, the first parameter passed to the $.tmpl() method is the name of a cached template. Working with Template Items In this final section, I want to devote some space to discussing Template Items. A new Template Item is created for each rendered instance of a template. For example, if you are displaying a list of 100 products with a template, then 100 Template Items are created. A Template Item has the following properties and methods: data – The data associated with the Template Instance. For example, a product. tmpl – The template associated with the Template Instance. parent – The parent template item if the template is nested. nodes – The HTML content of the template. calls – Used by {{wrap}} template tag. nest – Used by {{tmpl}} template tag. wrap – Used to imperatively enable wrapped templates. html – Used to filter content from a wrapped template. See the above section on wrapped templates. update – Used to re-render a template item. The last method – the update() method -- is especially interesting because it enables you to re-render a template item with new data or even a new template. For example, the following page displays a list of books. When you hover your mouse over any of the books, additional book details are displayed. In the following screenshot, details for ASP.NET Kick Start are displayed. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Item</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script id="bookDetailsTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} <p> ${description} </p> </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg", description: "The most comprehensive book on Microsoft’s new ASP.NET 4.. " }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg", description: "Writing for professional programmers, Walther explains the crucial concepts that make the Model-View-Controller (MVC) development paradigm work…" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg", description: "Visual Studio .NET is the premier development environment for creating .NET applications…." }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg", description: "ASP.NET MVC Unleashed for the iPhone…" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   There are two templates used to display a book: bookTemplate and bookDetailsTemplate. When you hover your mouse over a template item, the standard bookTemplate is swapped out for the bookDetailsTemplate. The bookDetailsTemplate displays a book description. The books are rendered with the bookTemplate with the following line of code: // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer");   The following code is used to swap the bookTemplate and the bookDetailsTemplate to show details for a book: // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); });   When you hover your mouse over a DIV element rendered by the bookTemplate, the mouseenter handler executes. First, this handler retrieves the Template Item associated with the DIV element by calling the tmplItem() method. The tmplItem() method returns a Template Item. Next, a new template is assigned to the Template Item. Notice that a compiled version of the bookDetailsTemplate is assigned to the Template Item’s tmpl property. The template is compiled earlier in the code by calling the template() method. Finally, the Template Item update() method is called to re-render the Template Item with the bookDetailsTemplate instead of the original bookTemplate. Summary This is a long blog entry and I still have not managed to cover all of the features of jQuery Templates J However, I’ve tried to cover the most important features of jQuery Templates such as template composition, template wrapping, and template items. To learn more about jQuery Templates, I recommend that you look at the documentation for jQuery Templates at the official jQuery website. Another great way to learn more about jQuery Templates is to look at the (unminified) source code.

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  • Building applications with WPF, MVVM and Prism(aka CAG)

    - by skjagini
    In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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  • Agile Development

    - by James Oloo Onyango
    Alot of literature has and is being written about agile developement and its surrounding philosophies. In my quest to find the best way to express the importance of agile methodologies, i have found Robert C. Martin's "A Satire Of Two Companies" to be both the most concise and thorough! Enjoy the read! Rufus Inc Project Kick Off Your name is Bob. The date is January 3, 2001, and your head still aches from the recent millennial revelry. You are sitting in a conference room with several managers and a group of your peers. You are a project team leader. Your boss is there, and he has brought along all of his team leaders. His boss called the meeting. "We have a new project to develop," says your boss's boss. Call him BB. The points in his hair are so long that they scrape the ceiling. Your boss's points are just starting to grow, but he eagerly awaits the day when he can leave Brylcream stains on the acoustic tiles. BB describes the essence of the new market they have identified and the product they want to develop to exploit this market. "We must have this new project up and working by fourth quarter October 1," BB demands. "Nothing is of higher priority, so we are cancelling your current project." The reaction in the room is stunned silence. Months of work are simply going to be thrown away. Slowly, a murmur of objection begins to circulate around the conference table.   His points give off an evil green glow as BB meets the eyes of everyone in the room. One by one, that insidious stare reduces each attendee to quivering lumps of protoplasm. It is clear that he will brook no discussion on this matter. Once silence has been restored, BB says, "We need to begin immediately. How long will it take you to do the analysis?" You raise your hand. Your boss tries to stop you, but his spitwad misses you and you are unaware of his efforts.   "Sir, we can't tell you how long the analysis will take until we have some requirements." "The requirements document won't be ready for 3 or 4 weeks," BB says, his points vibrating with frustration. "So, pretend that you have the requirements in front of you now. How long will you require for analysis?" No one breathes. Everyone looks around to see whether anyone has some idea. "If analysis goes beyond April 1, we have a problem. Can you finish the analysis by then?" Your boss visibly gathers his courage: "We'll find a way, sir!" His points grow 3 mm, and your headache increases by two Tylenol. "Good." BB smiles. "Now, how long will it take to do the design?" "Sir," you say. Your boss visibly pales. He is clearly worried that his 3 mms are at risk. "Without an analysis, it will not be possible to tell you how long design will take." BB's expression shifts beyond austere.   "PRETEND you have the analysis already!" he says, while fixing you with his vacant, beady little eyes. "How long will it take you to do the design?" Two Tylenol are not going to cut it. Your boss, in a desperate attempt to save his new growth, babbles: "Well, sir, with only six months left to complete the project, design had better take no longer than 3 months."   "I'm glad you agree, Smithers!" BB says, beaming. Your boss relaxes. He knows his points are secure. After a while, he starts lightly humming the Brylcream jingle. BB continues, "So, analysis will be complete by April 1, design will be complete by July 1, and that gives you 3 months to implement the project. This meeting is an example of how well our new consensus and empowerment policies are working. Now, get out there and start working. I'll expect to see TQM plans and QIT assignments on my desk by next week. Oh, and don't forget that your crossfunctional team meetings and reports will be needed for next month's quality audit." "Forget the Tylenol," you think to yourself as you return to your cubicle. "I need bourbon."   Visibly excited, your boss comes over to you and says, "Gosh, what a great meeting. I think we're really going to do some world shaking with this project." You nod in agreement, too disgusted to do anything else. "Oh," your boss continues, "I almost forgot." He hands you a 30-page document. "Remember that the SEI is coming to do an evaluation next week. This is the evaluation guide. You need to read through it, memorize it, and then shred it. It tells you how to answer any questions that the SEI auditors ask you. It also tells you what parts of the building you are allowed to take them to and what parts to avoid. We are determined to be a CMM level 3 organization by June!"   You and your peers start working on the analysis of the new project. This is difficult because you have no requirements. But from the 10-minute introduction given by BB on that fateful morning, you have some idea of what the product is supposed to do.   Corporate process demands that you begin by creating a use case document. You and your team begin enumerating use cases and drawing oval and stick diagrams. Philosophical debates break out among the team members. There is disagreement as to whether certain use cases should be connected with <<extends>> or <<includes>> relationships. Competing models are created, but nobody knows how to evaluate them. The debate continues, effectively paralyzing progress.   After a week, somebody finds the iceberg.com Web site, which recommends disposing entirely of <<extends>> and <<includes>> and replacing them with <<precedes>> and <<uses>>. The documents on this Web site, authored by Don Sengroiux, describes a method known as stalwart-analysis, which claims to be a step-by-step method for translating use cases into design diagrams. More competing use case models are created using this new scheme, but again, people can't agree on how to evaluate them. The thrashing continues. More and more, the use case meetings are driven by emotion rather than by reason. If it weren't for the fact that you don't have requirements, you'd be pretty upset by the lack of progress you are making. The requirements document arrives on February 15. And then again on February 20, 25, and every week thereafter. Each new version contradicts the previous one. Clearly, the marketing folks who are writing the requirements, empowered though they might be, are not finding consensus.   At the same time, several new competing use case templates have been proposed by the various team members. Each template presents its own particularly creative way of delaying progress. The debates rage on. On March 1, Prudence Putrigence, the process proctor, succeeds in integrating all the competing use case forms and templates into a single, all-encompassing form. Just the blank form is 15 pages long. She has managed to include every field that appeared on all the competing templates. She also presents a 159- page document describing how to fill out the use case form. All current use cases must be rewritten according to the new standard.   You marvel to yourself that it now requires 15 pages of fill-in-the-blank and essay questions to answer the question: What should the system do when the user presses Return? The corporate process (authored by L. E. Ott, famed author of "Holistic Analysis: A Progressive Dialectic for Software Engineers") insists that you discover all primary use cases, 87 percent of all secondary use cases, and 36.274 percent of all tertiary use cases before you can complete analysis and enter the design phase. You have no idea what a tertiary use case is. So in an attempt to meet this requirement, you try to get your use case document reviewed by the marketing department, which you hope will know what a tertiary use case is.   Unfortunately, the marketing folks are too busy with sales support to talk to you. Indeed, since the project started, you have not been able to get a single meeting with marketing, which has provided a never-ending stream of changing and contradictory requirements documents.   While one team has been spinning endlessly on the use case document, another team has been working out the domain model. Endless variations of UML documents are pouring out of this team. Every week, the model is reworked.   The team members can't decide whether to use <<interfaces>> or <<types>> in the model. A huge disagreement has been raging on the proper syntax and application of OCL. Others on the team just got back from a 5-day class on catabolism, and have been producing incredibly detailed and arcane diagrams that nobody else can fathom.   On March 27, with one week to go before analysis is to be complete, you have produced a sea of documents and diagrams but are no closer to a cogent analysis of the problem than you were on January 3. **** And then, a miracle happens.   **** On Saturday, April 1, you check your e-mail from home. You see a memo from your boss to BB. It states unequivocally that you are done with the analysis! You phone your boss and complain. "How could you have told BB that we were done with the analysis?" "Have you looked at a calendar lately?" he responds. "It's April 1!" The irony of that date does not escape you. "But we have so much more to think about. So much more to analyze! We haven't even decided whether to use <<extends>> or <<precedes>>!" "Where is your evidence that you are not done?" inquires your boss, impatiently. "Whaaa . . . ." But he cuts you off. "Analysis can go on forever; it has to be stopped at some point. And since this is the date it was scheduled to stop, it has been stopped. Now, on Monday, I want you to gather up all existing analysis materials and put them into a public folder. Release that folder to Prudence so that she can log it in the CM system by Monday afternoon. Then get busy and start designing."   As you hang up the phone, you begin to consider the benefits of keeping a bottle of bourbon in your bottom desk drawer. They threw a party to celebrate the on-time completion of the analysis phase. BB gave a colon-stirring speech on empowerment. And your boss, another 3 mm taller, congratulated his team on the incredible show of unity and teamwork. Finally, the CIO takes the stage to tell everyone that the SEI audit went very well and to thank everyone for studying and shredding the evaluation guides that were passed out. Level 3 now seems assured and will be awarded by June. (Scuttlebutt has it that managers at the level of BB and above are to receive significant bonuses once the SEI awards level 3.)   As the weeks flow by, you and your team work on the design of the system. Of course, you find that the analysis that the design is supposedly based on is flawedno, useless; no, worse than useless. But when you tell your boss that you need to go back and work some more on the analysis to shore up its weaker sections, he simply states, "The analysis phase is over. The only allowable activity is design. Now get back to it."   So, you and your team hack the design as best you can, unsure of whether the requirements have been properly analyzed. Of course, it really doesn't matter much, since the requirements document is still thrashing with weekly revisions, and the marketing department still refuses to meet with you.     The design is a nightmare. Your boss recently misread a book named The Finish Line in which the author, Mark DeThomaso, blithely suggested that design documents should be taken down to code-level detail. "If we are going to be working at that level of detail," you ask, "why don't we simply write the code instead?" "Because then you wouldn't be designing, of course. And the only allowable activity in the design phase is design!" "Besides," he continues, "we have just purchased a companywide license for Dandelion! This tool enables 'Round the Horn Engineering!' You are to transfer all design diagrams into this tool. It will automatically generate our code for us! It will also keep the design diagrams in sync with the code!" Your boss hands you a brightly colored shrinkwrapped box containing the Dandelion distribution. You accept it numbly and shuffle off to your cubicle. Twelve hours, eight crashes, one disk reformatting, and eight shots of 151 later, you finally have the tool installed on your server. You consider the week your team will lose while attending Dandelion training. Then you smile and think, "Any week I'm not here is a good week." Design diagram after design diagram is created by your team. Dandelion makes it very difficult to draw these diagrams. There are dozens and dozens of deeply nested dialog boxes with funny text fields and check boxes that must all be filled in correctly. And then there's the problem of moving classes between packages. At first, these diagram are driven from the use cases. But the requirements are changing so often that the use cases rapidly become meaningless. Debates rage about whether VISITOR or DECORATOR design patterns should be used. One developer refuses to use VISITOR in any form, claiming that it's not a properly object-oriented construct. Someone refuses to use multiple inheritance, since it is the spawn of the devil. Review meetings rapidly degenerate into debates about the meaning of object orientation, the definition of analysis versus design, or when to use aggregation versus association. Midway through the design cycle, the marketing folks announce that they have rethought the focus of the system. Their new requirements document is completely restructured. They have eliminated several major feature areas and replaced them with feature areas that they anticipate customer surveys will show to be more appropriate. You tell your boss that these changes mean that you need to reanalyze and redesign much of the system. But he says, "The analysis phase is system. But he says, "The analysis phase is over. The only allowable activity is design. Now get back to it."   You suggest that it might be better to create a simple prototype to show to the marketing folks and even some potential customers. But your boss says, "The analysis phase is over. The only allowable activity is design. Now get back to it." Hack, hack, hack, hack. You try to create some kind of a design document that might reflect the new requirements documents. However, the revolution of the requirements has not caused them to stop thrashing. Indeed, if anything, the wild oscillations of the requirements document have only increased in frequency and amplitude.   You slog your way through them.   On June 15, the Dandelion database gets corrupted. Apparently, the corruption has been progressive. Small errors in the DB accumulated over the months into bigger and bigger errors. Eventually, the CASE tool just stopped working. Of course, the slowly encroaching corruption is present on all the backups. Calls to the Dandelion technical support line go unanswered for several days. Finally, you receive a brief e-mail from Dandelion, informing you that this is a known problem and that the solution is to purchase the new version, which they promise will be ready some time next quarter, and then reenter all the diagrams by hand.   ****   Then, on July 1 another miracle happens! You are done with the design!   Rather than go to your boss and complain, you stock your middle desk drawer with some vodka.   **** They threw a party to celebrate the on-time completion of the design phase and their graduation to CMM level 3. This time, you find BB's speech so stirring that you have to use the restroom before it begins. New banners and plaques are all over your workplace. They show pictures of eagles and mountain climbers, and they talk about teamwork and empowerment. They read better after a few scotches. That reminds you that you need to clear out your file cabinet to make room for the brandy. You and your team begin to code. But you rapidly discover that the design is lacking in some significant areas. Actually, it's lacking any significance at all. You convene a design session in one of the conference rooms to try to work through some of the nastier problems. But your boss catches you at it and disbands the meeting, saying, "The design phase is over. The only allowable activity is coding. Now get back to it."   ****   The code generated by Dandelion is really hideous. It turns out that you and your team were using association and aggregation the wrong way, after all. All the generated code has to be edited to correct these flaws. Editing this code is extremely difficult because it has been instrumented with ugly comment blocks that have special syntax that Dandelion needs in order to keep the diagrams in sync with the code. If you accidentally alter one of these comments, the diagrams will be regenerated incorrectly. It turns out that "Round the Horn Engineering" requires an awful lot of effort. The more you try to keep the code compatible with Dandelion, the more errors Dandelion generates. In the end, you give up and decide to keep the diagrams up to date manually. A second later, you decide that there's no point in keeping the diagrams up to date at all. Besides, who has time?   Your boss hires a consultant to build tools to count the number of lines of code that are being produced. He puts a big thermometer graph on the wall with the number 1,000,000 on the top. Every day, he extends the red line to show how many lines have been added. Three days after the thermometer appears on the wall, your boss stops you in the hall. "That graph isn't growing quickly enough. We need to have a million lines done by October 1." "We aren't even sh-sh-sure that the proshect will require a m-million linezh," you blather. "We have to have a million lines done by October 1," your boss reiterates. His points have grown again, and the Grecian formula he uses on them creates an aura of authority and competence. "Are you sure your comment blocks are big enough?" Then, in a flash of managerial insight, he says, "I have it! I want you to institute a new policy among the engineers. No line of code is to be longer than 20 characters. Any such line must be split into two or more preferably more. All existing code needs to be reworked to this standard. That'll get our line count up!"   You decide not to tell him that this will require two unscheduled work months. You decide not to tell him anything at all. You decide that intravenous injections of pure ethanol are the only solution. You make the appropriate arrangements. Hack, hack, hack, and hack. You and your team madly code away. By August 1, your boss, frowning at the thermometer on the wall, institutes a mandatory 50-hour workweek.   Hack, hack, hack, and hack. By September 1st, the thermometer is at 1.2 million lines and your boss asks you to write a report describing why you exceeded the coding budget by 20 percent. He institutes mandatory Saturdays and demands that the project be brought back down to a million lines. You start a campaign of remerging lines. Hack, hack, hack, and hack. Tempers are flaring; people are quitting; QA is raining trouble reports down on you. Customers are demanding installation and user manuals; salespeople are demanding advance demonstrations for special customers; the requirements document is still thrashing, the marketing folks are complaining that the product isn't anything like they specified, and the liquor store won't accept your credit card anymore. Something has to give.    On September 15, BB calls a meeting. As he enters the room, his points are emitting clouds of steam. When he speaks, the bass overtones of his carefully manicured voice cause the pit of your stomach to roll over. "The QA manager has told me that this project has less than 50 percent of the required features implemented. He has also informed me that the system crashes all the time, yields wrong results, and is hideously slow. He has also complained that he cannot keep up with the continuous train of daily releases, each more buggy than the last!" He stops for a few seconds, visibly trying to compose himself. "The QA manager estimates that, at this rate of development, we won't be able to ship the product until December!" Actually, you think it's more like March, but you don't say anything. "December!" BB roars with such derision that people duck their heads as though he were pointing an assault rifle at them. "December is absolutely out of the question. Team leaders, I want new estimates on my desk in the morning. I am hereby mandating 65-hour work weeks until this project is complete. And it better be complete by November 1."   As he leaves the conference room, he is heard to mutter: "Empowermentbah!" * * * Your boss is bald; his points are mounted on BB's wall. The fluorescent lights reflecting off his pate momentarily dazzle you. "Do you have anything to drink?" he asks. Having just finished your last bottle of Boone's Farm, you pull a bottle of Thunderbird from your bookshelf and pour it into his coffee mug. "What's it going to take to get this project done? " he asks. "We need to freeze the requirements, analyze them, design them, and then implement them," you say callously. "By November 1?" your boss exclaims incredulously. "No way! Just get back to coding the damned thing." He storms out, scratching his vacant head.   A few days later, you find that your boss has been transferred to the corporate research division. Turnover has skyrocketed. Customers, informed at the last minute that their orders cannot be fulfilled on time, have begun to cancel their orders. Marketing is re-evaluating whether this product aligns with the overall goals of the company. Memos fly, heads roll, policies change, and things are, overall, pretty grim. Finally, by March, after far too many sixty-five hour weeks, a very shaky version of the software is ready. In the field, bug-discovery rates are high, and the technical support staff are at their wits' end, trying to cope with the complaints and demands of the irate customers. Nobody is happy.   In April, BB decides to buy his way out of the problem by licensing a product produced by Rupert Industries and redistributing it. The customers are mollified, the marketing folks are smug, and you are laid off.     Rupert Industries: Project Alpha   Your name is Robert. The date is January 3, 2001. The quiet hours spent with your family this holiday have left you refreshed and ready for work. You are sitting in a conference room with your team of professionals. The manager of the division called the meeting. "We have some ideas for a new project," says the division manager. Call him Russ. He is a high-strung British chap with more energy than a fusion reactor. He is ambitious and driven but understands the value of a team. Russ describes the essence of the new market opportunity the company has identified and introduces you to Jane, the marketing manager, who is responsible for defining the products that will address it. Addressing you, Jane says, "We'd like to start defining our first product offering as soon as possible. When can you and your team meet with me?" You reply, "We'll be done with the current iteration of our project this Friday. We can spare a few hours for you between now and then. After that, we'll take a few people from the team and dedicate them to you. We'll begin hiring their replacements and the new people for your team immediately." "Great," says Russ, "but I want you to understand that it is critical that we have something to exhibit at the trade show coming up this July. If we can't be there with something significant, we'll lose the opportunity."   "I understand," you reply. "I don't yet know what it is that you have in mind, but I'm sure we can have something by July. I just can't tell you what that something will be right now. In any case, you and Jane are going to have complete control over what we developers do, so you can rest assured that by July, you'll have the most important things that can be accomplished in that time ready to exhibit."   Russ nods in satisfaction. He knows how this works. Your team has always kept him advised and allowed him to steer their development. He has the utmost confidence that your team will work on the most important things first and will produce a high-quality product.   * * *   "So, Robert," says Jane at their first meeting, "How does your team feel about being split up?" "We'll miss working with each other," you answer, "but some of us were getting pretty tired of that last project and are looking forward to a change. So, what are you people cooking up?" Jane beams. "You know how much trouble our customers currently have . . ." And she spends a half hour or so describing the problem and possible solution. "OK, wait a second" you respond. "I need to be clear about this." And so you and Jane talk about how this system might work. Some of her ideas aren't fully formed. You suggest possible solutions. She likes some of them. You continue discussing.   During the discussion, as each new topic is addressed, Jane writes user story cards. Each card represents something that the new system has to do. The cards accumulate on the table and are spread out in front of you. Both you and Jane point at them, pick them up, and make notes on them as you discuss the stories. The cards are powerful mnemonic devices that you can use to represent complex ideas that are barely formed.   At the end of the meeting, you say, "OK, I've got a general idea of what you want. I'm going to talk to the team about it. I imagine they'll want to run some experiments with various database structures and presentation formats. Next time we meet, it'll be as a group, and we'll start identifying the most important features of the system."   A week later, your nascent team meets with Jane. They spread the existing user story cards out on the table and begin to get into some of the details of the system. The meeting is very dynamic. Jane presents the stories in the order of their importance. There is much discussion about each one. The developers are concerned about keeping the stories small enough to estimate and test. So they continually ask Jane to split one story into several smaller stories. Jane is concerned that each story have a clear business value and priority, so as she splits them, she makes sure that this stays true.   The stories accumulate on the table. Jane writes them, but the developers make notes on them as needed. Nobody tries to capture everything that is said; the cards are not meant to capture everything but are simply reminders of the conversation.   As the developers become more comfortable with the stories, they begin writing estimates on them. These estimates are crude and budgetary, but they give Jane an idea of what the story will cost.   At the end of the meeting, it is clear that many more stories could be discussed. It is also clear that the most important stories have been addressed and that they represent several months worth of work. Jane closes the meeting by taking the cards with her and promising to have a proposal for the first release in the morning.   * * *   The next morning, you reconvene the meeting. Jane chooses five cards and places them on the table. "According to your estimates, these cards represent about one perfect team-week's worth of work. The last iteration of the previous project managed to get one perfect team-week done in 3 real weeks. If we can get these five stories done in 3 weeks, we'll be able to demonstrate them to Russ. That will make him feel very comfortable about our progress." Jane is pushing it. The sheepish look on her face lets you know that she knows it too. You reply, "Jane, this is a new team, working on a new project. It's a bit presumptuous to expect that our velocity will be the same as the previous team's. However, I met with the team yesterday afternoon, and we all agreed that our initial velocity should, in fact, be set to one perfectweek for every 3 real-weeks. So you've lucked out on this one." "Just remember," you continue, "that the story estimates and the story velocity are very tentative at this point. We'll learn more when we plan the iteration and even more when we implement it."   Jane looks over her glasses at you as if to say "Who's the boss around here, anyway?" and then smiles and says, "Yeah, don't worry. I know the drill by now."Jane then puts 15 more cards on the table. She says, "If we can get all these cards done by the end of March, we can turn the system over to our beta test customers. And we'll get good feedback from them."   You reply, "OK, so we've got our first iteration defined, and we have the stories for the next three iterations after that. These four iterations will make our first release."   "So," says Jane, can you really do these five stories in the next 3 weeks?" "I don't know for sure, Jane," you reply. "Let's break them down into tasks and see what we get."   So Jane, you, and your team spend the next several hours taking each of the five stories that Jane chose for the first iteration and breaking them down into small tasks. The developers quickly realize that some of the tasks can be shared between stories and that other tasks have commonalities that can probably be taken advantage of. It is clear that potential designs are popping into the developers' heads. From time to time, they form little discussion knots and scribble UML diagrams on some cards.   Soon, the whiteboard is filled with the tasks that, once completed, will implement the five stories for this iteration. You start the sign-up process by saying, "OK, let's sign up for these tasks." "I'll take the initial database generation." Says Pete. "That's what I did on the last project, and this doesn't look very different. I estimate it at two of my perfect workdays." "OK, well, then, I'll take the login screen," says Joe. "Aw, darn," says Elaine, the junior member of the team, "I've never done a GUI, and kinda wanted to try that one."   "Ah, the impatience of youth," Joe says sagely, with a wink in your direction. "You can assist me with it, young Jedi." To Jane: "I think it'll take me about three of my perfect workdays."   One by one, the developers sign up for tasks and estimate them in terms of their own perfect workdays. Both you and Jane know that it is best to let the developers volunteer for tasks than to assign the tasks to them. You also know full well that you daren't challenge any of the developers' estimates. You know these people, and you trust them. You know that they are going to do the very best they can.   The developers know that they can't sign up for more perfect workdays than they finished in the last iteration they worked on. Once each developer has filled his or her schedule for the iteration, they stop signing up for tasks.   Eventually, all the developers have stopped signing up for tasks. But, of course, tasks are still left on the board.   "I was worried that that might happen," you say, "OK, there's only one thing to do, Jane. We've got too much to do in this iteration. What stories or tasks can we remove?" Jane sighs. She knows that this is the only option. Working overtime at the beginning of a project is insane, and projects where she's tried it have not fared well.   So Jane starts to remove the least-important functionality. "Well, we really don't need the login screen just yet. We can simply start the system in the logged-in state." "Rats!" cries Elaine. "I really wanted to do that." "Patience, grasshopper." says Joe. "Those who wait for the bees to leave the hive will not have lips too swollen to relish the honey." Elaine looks confused. Everyone looks confused. "So . . .," Jane continues, "I think we can also do away with . . ." And so, bit by bit, the list of tasks shrinks. Developers who lose a task sign up for one of the remaining ones.   The negotiation is not painless. Several times, Jane exhibits obvious frustration and impatience. Once, when tensions are especially high, Elaine volunteers, "I'll work extra hard to make up some of the missing time." You are about to correct her when, fortunately, Joe looks her in the eye and says, "When once you proceed down the dark path, forever will it dominate your destiny."   In the end, an iteration acceptable to Jane is reached. It's not what Jane wanted. Indeed, it is significantly less. But it's something the team feels that can be achieved in the next 3 weeks.   And, after all, it still addresses the most important things that Jane wanted in the iteration. "So, Jane," you say when things had quieted down a bit, "when can we expect acceptance tests from you?" Jane sighs. This is the other side of the coin. For every story the development team implements,   Jane must supply a suite of acceptance tests that prove that it works. And the team needs these long before the end of the iteration, since they will certainly point out differences in the way Jane and the developers imagine the system's behaviour.   "I'll get you some example test scripts today," Jane promises. "I'll add to them every day after that. You'll have the entire suite by the middle of the iteration."   * * *   The iteration begins on Monday morning with a flurry of Class, Responsibilities, Collaborators sessions. By midmorning, all the developers have assembled into pairs and are rapidly coding away. "And now, my young apprentice," Joe says to Elaine, "you shall learn the mysteries of test-first design!"   "Wow, that sounds pretty rad," Elaine replies. "How do you do it?" Joe beams. It's clear that he has been anticipating this moment. "OK, what does the code do right now?" "Huh?" replied Elaine, "It doesn't do anything at all; there is no code."   "So, consider our task; can you think of something the code should do?" "Sure," Elaine said with youthful assurance, "First, it should connect to the database." "And thereupon, what must needs be required to connecteth the database?" "You sure talk weird," laughed Elaine. "I think we'd have to get the database object from some registry and call the Connect() method. "Ah, astute young wizard. Thou perceives correctly that we requireth an object within which we can cacheth the database object." "Is 'cacheth' really a word?" "It is when I say it! So, what test can we write that we know the database registry should pass?" Elaine sighs. She knows she'll just have to play along. "We should be able to create a database object and pass it to the registry in a Store() method. And then we should be able to pull it out of the registry with a Get() method and make sure it's the same object." "Oh, well said, my prepubescent sprite!" "Hay!" "So, now, let's write a test function that proves your case." "But shouldn't we write the database object and registry object first?" "Ah, you've much to learn, my young impatient one. Just write the test first." "But it won't even compile!" "Are you sure? What if it did?" "Uh . . ." "Just write the test, Elaine. Trust me." And so Joe, Elaine, and all the other developers began to code their tasks, one test case at a time. The room in which they worked was abuzz with the conversations between the pairs. The murmur was punctuated by an occasional high five when a pair managed to finish a task or a difficult test case.   As development proceeded, the developers changed partners once or twice a day. Each developer got to see what all the others were doing, and so knowledge of the code spread generally throughout the team.   Whenever a pair finished something significant whether a whole task or simply an important part of a task they integrated what they had with the rest of the system. Thus, the code base grew daily, and integration difficulties were minimized.   The developers communicated with Jane on a daily basis. They'd go to her whenever they had a question about the functionality of the system or the interpretation of an acceptance test case.   Jane, good as her word, supplied the team with a steady stream of acceptance test scripts. The team read these carefully and thereby gained a much better understanding of what Jane expected the system to do. By the beginning of the second week, there was enough functionality to demonstrate to Jane. She watched eagerly as the demonstration passed test case after test case. "This is really cool," Jane said as the demonstration finally ended. "But this doesn't seem like one-third of the tasks. Is your velocity slower than anticipated?"   You grimace. You'd been waiting for a good time to mention this to Jane but now she was forcing the issue. "Yes, unfortunately, we are going more slowly than we had expected. The new application server we are using is turning out to be a pain to configure. Also, it takes forever to reboot, and we have to reboot it whenever we make even the slightest change to its configuration."   Jane eyes you with suspicion. The stress of last Monday's negotiations had still not entirely dissipated. She says, "And what does this mean to our schedule? We can't slip it again, we just can't. Russ will have a fit! He'll haul us all into the woodshed and ream us some new ones."   You look Jane right in the eyes. There's no pleasant way to give someone news like this. So you just blurt out, "Look, if things keep going like they're going, we're not going to be done with everything by next Friday. Now it's possible that we'll figure out a way to go faster. But, frankly, I wouldn't depend on that. You should start thinking about one or two tasks that could be removed from the iteration without ruining the demonstration for Russ. Come hell or high water, we are going to give that demonstration on Friday, and I don't think you want us to choose which tasks to omit."   "Aw forchrisakes!" Jane barely manages to stifle yelling that last word as she stalks away, shaking her head. Not for the first time, you say to yourself, "Nobody ever promised me project management would be easy." You are pretty sure it won't be the last time, either.   Actually, things went a bit better than you had hoped. The team did, in fact, have to drop one task from the iteration, but Jane had chosen wisely, and the demonstration for Russ went without a hitch. Russ was not impressed with the progress, but neither was he dismayed. He simply said, "This is pretty good. But remember, we have to be able to demonstrate this system at the trade show in July, and at this rate, it doesn't look like you'll have all that much to show." Jane, whose attitude had improved dramatically with the completion of the iteration, responded to Russ by saying, "Russ, this team is working hard, and well. When July comes around, I am confident that we'll have something significant to demonstrate. It won't be everything, and some of it may be smoke and mirrors, but we'll have something."   Painful though the last iteration was, it had calibrated your velocity numbers. The next iteration went much better. Not because your team got more done than in the last iteration but simply because the team didn't have to remove any tasks or stories in the middle of the iteration.   By the start of the fourth iteration, a natural rhythm has been established. Jane, you, and the team know exactly what to expect from one another. The team is running hard, but the pace is sustainable. You are confident that the team can keep up this pace for a year or more.   The number of surprises in the schedule diminishes to near zero; however, the number of surprises in the requirements does not. Jane and Russ frequently look over the growing system and make recommendations or changes to the existing functionality. But all parties realize that these changes take time and must be scheduled. So the changes do not cause anyone's expectations to be violated. In March, there is a major demonstration of the system to the board of directors. The system is very limited and is not yet in a form good enough to take to the trade show, but progress is steady, and the board is reasonably impressed.   The second release goes even more smoothly than the first. By now, the team has figured out a way to automate Jane's acceptance test scripts. The team has also refactored the design of the system to the point that it is really easy to add new features and change old ones. The second release was done by the end of June and was taken to the trade show. It had less in it than Jane and Russ would have liked, but it did demonstrate the most important features of the system. Although customers at the trade show noticed that certain features were missing, they were very impressed overall. You, Russ, and Jane all returned from the trade show with smiles on your faces. You all felt as though this project was a winner.   Indeed, many months later, you are contacted by Rufus Inc. That company had been working on a system like this for its internal operations. Rufus has canceled the development of that system after a death-march project and is negotiating to license your technology for its environment.   Indeed, things are looking up!

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  • Using the West Wind Web Toolkit to set up AJAX and REST Services

    - by Rick Strahl
    I frequently get questions about which option to use for creating AJAX and REST backends for ASP.NET applications. There are many solutions out there to do this actually, but when I have a choice - not surprisingly - I fall back to my own tools in the West Wind West Wind Web Toolkit. I've talked a bunch about the 'in-the-box' solutions in the past so for a change in this post I'll talk about the tools that I use in my own and customer applications to handle AJAX and REST based access to service resources using the West Wind West Wind Web Toolkit. Let me preface this by saying that I like things to be easy. Yes flexible is very important as well but not at the expense of over-complexity. The goal I've had with my tools is make it drop dead easy, with good performance while providing the core features that I'm after, which are: Easy AJAX/JSON Callbacks Ability to return any kind of non JSON content (string, stream, byte[], images) Ability to work with both XML and JSON interchangeably for input/output Access endpoints via POST data, RPC JSON calls, GET QueryString values or Routing interface Easy to use generic JavaScript client to make RPC calls (same syntax, just what you need) Ability to create clean URLS with Routing Ability to use standard ASP.NET HTTP Stack for HTTP semantics It's all about options! In this post I'll demonstrate most of these features (except XML) in a few simple and short samples which you can download. So let's take a look and see how you can build an AJAX callback solution with the West Wind Web Toolkit. Installing the Toolkit Assemblies The easiest and leanest way of using the Toolkit in your Web project is to grab it via NuGet: West Wind Web and AJAX Utilities (Westwind.Web) and drop it into the project by right clicking in your Project and choosing Manage NuGet Packages from anywhere in the Project.   When done you end up with your project looking like this: What just happened? Nuget added two assemblies - Westwind.Web and Westwind.Utilities and the client ww.jquery.js library. It also added a couple of references into web.config: The default namespaces so they can be accessed in pages/views and a ScriptCompressionModule that the toolkit optionally uses to compress script resources served from within the assembly (namely ww.jquery.js and optionally jquery.js). Creating a new Service The West Wind Web Toolkit supports several ways of creating and accessing AJAX services, but for this post I'll stick to the lower level approach that works from any plain HTML page or of course MVC, WebForms, WebPages. There's also a WebForms specific control that makes this even easier but I'll leave that for another post. So, to create a new standalone AJAX/REST service we can create a new HttpHandler in the new project either as a pure class based handler or as a generic .ASHX handler. Both work equally well, but generic handlers don't require any web.config configuration so I'll use that here. In the root of the project add a Generic Handler. I'm going to call this one StockService.ashx. Once the handler has been created, edit the code and remove all of the handler body code. Then change the base class to CallbackHandler and add methods that have a [CallbackMethod] attribute. Here's the modified base handler implementation now looks like with an added HelloWorld method: using System; using Westwind.Web; namespace WestWindWebAjax { /// <summary> /// Handler implements CallbackHandler to provide REST/AJAX services /// </summary> public class SampleService : CallbackHandler { [CallbackMethod] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } } } Notice that the class inherits from CallbackHandler and that the HelloWorld service method is marked up with [CallbackMethod]. We're done here. Services Urlbased Syntax Once you compile, the 'service' is live can respond to requests. All CallbackHandlers support input in GET and POST formats, and can return results as JSON or XML. To check our fancy HelloWorld method we can now access the service like this: http://localhost/WestWindWebAjax/StockService.ashx?Method=HelloWorld&name=Rick which produces a default JSON response - in this case a string (wrapped in quotes as it's JSON): (note by default JSON will be downloaded by most browsers not displayed - various options are available to view JSON right in the browser) If I want to return the same data as XML I can tack on a &format=xml at the end of the querystring which produces: <string>Hello Rick. Time is: 11/1/2011 12:11:13 PM</string> Cleaner URLs with Routing Syntax If you want cleaner URLs for each operation you can also configure custom routes on a per URL basis similar to the way that WCF REST does. To do this you need to add a new RouteHandler to your application's startup code in global.asax.cs one for each CallbackHandler based service you create: protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); } With this code in place you can now add RouteUrl properties to any of your service methods. For the HelloWorld method that doesn't make a ton of sense but here is what a routed clean URL might look like in definition: [CallbackMethod(RouteUrl="stocks/HelloWorld/{name}")] public string HelloWorld(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } The same URL I previously used now becomes a bit shorter and more readable with: http://localhost/WestWindWebAjax/HelloWorld/Rick It's an easy way to create cleaner URLs and still get the same functionality. Calling the Service with $.getJSON() Since the result produced is JSON you can now easily consume this data using jQuery's getJSON method. First we need a couple of scripts - jquery.js and ww.jquery.js in the page: <!DOCTYPE html> <html> <head> <link href="Css/Westwind.css" rel="stylesheet" type="text/css" /> <script src="scripts/jquery.min.js" type="text/javascript"></script> <script src="scripts/ww.jquery.min.js" type="text/javascript"></script> </head> <body> Next let's add a small HelloWorld example form (what else) that has a single textbox to type a name, a button and a div tag to receive the result: <fieldset> <legend>Hello World</legend> Please enter a name: <input type="text" name="txtHello" id="txtHello" value="" /> <input type="button" id="btnSayHello" value="Say Hello (POST)" /> <input type="button" id="btnSayHelloGet" value="Say Hello (GET)" /> <div id="divHelloMessage" class="errordisplay" style="display:none;width: 450px;" > </div> </fieldset> Then to call the HelloWorld method a little jQuery is used to hook the document startup and the button click followed by the $.getJSON call to retrieve the data from the server. <script type="text/javascript"> $(document).ready(function () { $("#btnSayHelloGet").click(function () { $.getJSON("SampleService.ashx", { Method: "HelloWorld", name: $("#txtHello").val() }, function (result) { $("#divHelloMessage") .text(result) .fadeIn(1000); }); });</script> .getJSON() expects a full URL to the endpoint of our service, which is the ASHX file. We can either provide a full URL (SampleService.ashx?Method=HelloWorld&name=Rick) or we can just provide the base URL and an object that encodes the query string parameters for us using an object map that has a property that matches each parameter for the server method. We can also use the clean URL routing syntax, but using the object parameter encoding actually is safer as the parameters will get properly encoded by jQuery. The result returned is whatever the result on the server method is - in this case a string. The string is applied to the divHelloMessage element and we're done. Obviously this is a trivial example, but it demonstrates the basics of getting a JSON response back to the browser. AJAX Post Syntax - using ajaxCallMethod() The previous example allows you basic control over the data that you send to the server via querystring parameters. This works OK for simple values like short strings, numbers and boolean values, but doesn't really work if you need to pass something more complex like an object or an array back up to the server. To handle traditional RPC type messaging where the idea is to map server side functions and results to a client side invokation, POST operations can be used. The easiest way to use this functionality is to use ww.jquery.js and the ajaxCallMethod() function. ww.jquery wraps jQuery's AJAX functions and knows implicitly how to call a CallbackServer method with parameters and parse the result. Let's look at another simple example that posts a simple value but returns something more interesting. Let's start with the service method: [CallbackMethod(RouteUrl="stocks/{symbol}")] public StockQuote GetStockQuote(string symbol) { Response.Cache.SetExpires(DateTime.UtcNow.Add(new TimeSpan(0, 2, 0))); StockServer server = new StockServer(); var quote = server.GetStockQuote(symbol); if (quote == null) throw new ApplicationException("Invalid Symbol passed."); return quote; } This sample utilizes a small StockServer helper class (included in the sample) that downloads a stock quote from Yahoo's financial site via plain HTTP GET requests and formats it into a StockQuote object. Lets create a small HTML block that lets us query for the quote and display it: <fieldset> <legend>Single Stock Quote</legend> Please enter a stock symbol: <input type="text" name="txtSymbol" id="txtSymbol" value="msft" /> <input type="button" id="btnStockQuote" value="Get Quote" /> <div id="divStockDisplay" class="errordisplay" style="display:none; width: 450px;"> <div class="label-left">Company:</div> <div id="stockCompany"></div> <div class="label-left">Last Price:</div> <div id="stockLastPrice"></div> <div class="label-left">Quote Time:</div> <div id="stockQuoteTime"></div> </div> </fieldset> The final result looks something like this:   Let's hook up the button handler to fire the request and fill in the data as shown: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").show().fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, HH:mm EST")); }, onPageError); }); So we point at SampleService.ashx and the GetStockQuote method, passing a single parameter of the input symbol value. Then there are two handlers for success and failure callbacks.  The success handler is the interesting part - it receives the stock quote as a result and assigns its values to various 'holes' in the stock display elements. The data that comes back over the wire is JSON and it looks like this: { "Symbol":"MSFT", "Company":"Microsoft Corpora", "OpenPrice":26.11, "LastPrice":26.01, "NetChange":0.02, "LastQuoteTime":"2011-11-03T02:00:00Z", "LastQuoteTimeString":"Nov. 11, 2011 4:20pm" } which is an object representation of the data. JavaScript can evaluate this JSON string back into an object easily and that's the reslut that gets passed to the success function. The quote data is then applied to existing page content by manually selecting items and applying them. There are other ways to do this more elegantly like using templates, but here we're only interested in seeing how the data is returned. The data in the object is typed - LastPrice is a number and QuoteTime is a date. Note about the date value: JavaScript doesn't have a date literal although the JSON embedded ISO string format used above  ("2011-11-03T02:00:00Z") is becoming fairly standard for JSON serializers. However, JSON parsers don't deserialize dates by default and return them by string. This is why the StockQuote actually returns a string value of LastQuoteTimeString for the same date. ajaxMethodCallback always converts dates properly into 'real' dates and the example above uses the real date value along with a .formatDate() data extension (also in ww.jquery.js) to display the raw date properly. Errors and Exceptions So what happens if your code fails? For example if I pass an invalid stock symbol to the GetStockQuote() method you notice that the code does this: if (quote == null) throw new ApplicationException("Invalid Symbol passed."); CallbackHandler automatically pushes the exception message back to the client so it's easy to pick up the error message. Regardless of what kind of error occurs: Server side, client side, protocol errors - any error will fire the failure handler with an error object parameter. The error is returned to the client via a JSON response in the error callback. In the previous examples I called onPageError which is a generic routine in ww.jquery that displays a status message on the bottom of the screen. But of course you can also take over the error handling yourself: $("#btnStockQuote").click(function () { ajaxCallMethod("SampleService.ashx", "GetStockQuote", [$("#txtSymbol").val()], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); }, function (error, xhr) { $("#divErrorDisplay").text(error.message).fadeIn(1000); }); }); The error object has a isCallbackError, message and  stackTrace properties, the latter of which is only populated when running in Debug mode, and this object is returned for all errors: Client side, transport and server side errors. Regardless of which type of error you get the same object passed (as well as the XHR instance optionally) which makes for a consistent error retrieval mechanism. Specifying HttpVerbs You can also specify HTTP Verbs that are allowed using the AllowedHttpVerbs option on the CallbackMethod attribute: [CallbackMethod(AllowedHttpVerbs=HttpVerbs.GET | HttpVerbs.POST)] public string HelloWorld(string name) { … } If you're building REST style API's this might be useful to force certain request semantics onto the client calling. For the above if call with a non-allowed HttpVerb the request returns a 405 error response along with a JSON (or XML) error object result. The default behavior is to allow all verbs access (HttpVerbs.All). Passing in object Parameters Up to now the parameters I passed were very simple. But what if you need to send something more complex like an object or an array? Let's look at another example now that passes an object from the client to the server. Keeping with the Stock theme here lets add a method called BuyOrder that lets us buy some shares for a stock. Consider the following service method that receives an StockBuyOrder object as a parameter: [CallbackMethod] public string BuyStock(StockBuyOrder buyOrder) { var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } public class StockBuyOrder { public string Symbol { get; set; } public int Quantity { get; set; } public DateTime BuyOn { get; set; } public StockBuyOrder() { BuyOn = DateTime.Now; } } This is a contrived do-nothing example that simply echoes back what was passed in, but it demonstrates how you can pass complex data to a callback method. On the client side we now have a very simple form that captures the three values on a form: <fieldset> <legend>Post a Stock Buy Order</legend> Enter a symbol: <input type="text" name="txtBuySymbol" id="txtBuySymbol" value="GLD" />&nbsp;&nbsp; Qty: <input type="text" name="txtBuyQty" id="txtBuyQty" value="10" style="width: 50px" />&nbsp;&nbsp; Buy on: <input type="text" name="txtBuyOn" id="txtBuyOn" value="<%= DateTime.Now.ToString("d") %>" style="width: 70px;" /> <input type="button" id="btnBuyStock" value="Buy Stock" /> <div id="divStockBuyMessage" class="errordisplay" style="display:none"></div> </fieldset> The completed form and demo then looks something like this:   The client side code that picks up the input values and assigns them to object properties and sends the AJAX request looks like this: $("#btnBuyStock").click(function () { // create an object map that matches StockBuyOrder signature var buyOrder = { Symbol: $("#txtBuySymbol").val(), Quantity: $("#txtBuyQty").val() * 1, // number Entered: new Date() } ajaxCallMethod("SampleService.ashx", "BuyStock", [buyOrder], function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError); }); The code creates an object and attaches the properties that match the server side object passed to the BuyStock method. Each property that you want to update needs to be included and the type must match (ie. string, number, date in this case). Any missing properties will not be set but also not cause any errors. Pass POST data instead of Objects In the last example I collected a bunch of values from form variables and stuffed them into object variables in JavaScript code. While that works, often times this isn't really helping - I end up converting my types on the client and then doing another conversion on the server. If lots of input controls are on a page and you just want to pick up the values on the server via plain POST variables - that can be done too - and it makes sense especially if you're creating and filling the client side object only to push data to the server. Let's add another method to the server that once again lets us buy a stock. But this time let's not accept a parameter but rather send POST data to the server. Here's the server method receiving POST data: [CallbackMethod] public string BuyStockPost() { StockBuyOrder buyOrder = new StockBuyOrder(); buyOrder.Symbol = Request.Form["txtBuySymbol"]; ; int qty; int.TryParse(Request.Form["txtBuyQuantity"], out qty); buyOrder.Quantity = qty; DateTime time; DateTime.TryParse(Request.Form["txtBuyBuyOn"], out time); buyOrder.BuyOn = time; // Or easier way yet //FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); var server = new StockServer(); var quote = server.GetStockQuote(buyOrder.Symbol); if (quote == null) throw new ApplicationException("Invalid or missing stock symbol."); return string.Format("You're buying {0} shares of {1} ({2}) stock at {3} for a total of {4} on {5}.", buyOrder.Quantity, quote.Company, quote.Symbol, quote.LastPrice.ToString("c"), (quote.LastPrice * buyOrder.Quantity).ToString("c"), buyOrder.BuyOn.ToString("MMM d")); } Clearly we've made this server method take more code than it did with the object parameter. We've basically moved the parameter assignment logic from the client to the server. As a result the client code to call this method is now a bit shorter since there's no client side shuffling of values from the controls to an object. $("#btnBuyStockPost").click(function () { ajaxCallMethod("SampleService.ashx", "BuyStockPost", [], // Note: No parameters - function (result) { $("#divStockBuyMessage").text(result).fadeIn(1000); }, onPageError, // Force all page Form Variables to be posted { postbackMode: "Post" }); }); The client simply calls the BuyStockQuote method and pushes all the form variables from the page up to the server which parses them instead. The feature that makes this work is one of the options you can pass to the ajaxCallMethod() function: { postbackMode: "Post" }); which directs the function to include form variable POST data when making the service call. Other options include PostNoViewState (for WebForms to strip out WebForms crap vars), PostParametersOnly (default), None. If you pass parameters those are always posted to the server except when None is set. The above code can be simplified a bit by using the FormVariableBinder helper, which can unbind form variables directly into an object: FormVariableBinder.Unbind(buyOrder,null,"txtBuy"); which replaces the manual Request.Form[] reading code. It receives the object to unbind into, a string of properties to skip, and an optional prefix which is stripped off form variables to match property names. The component is similar to the MVC model binder but it's independent of MVC. Returning non-JSON Data CallbackHandler also supports returning non-JSON/XML data via special return types. You can return raw non-JSON encoded strings like this: [CallbackMethod(ReturnAsRawString=true,ContentType="text/plain")] public string HelloWorldNoJSON(string name) { return "Hello " + name + ". Time is: " + DateTime.Now.ToString(); } Calling this method results in just a plain string - no JSON encoding with quotes around the result. This can be useful if your server handling code needs to return a string or HTML result that doesn't fit well for a page or other UI component. Any string output can be returned. You can also return binary data. Stream, byte[] and Bitmap/Image results are automatically streamed back to the client. Notice that you should set the ContentType of the request either on the CallbackMethod attribute or using Response.ContentType. This ensures the Web Server knows how to display your binary response. Using a stream response makes it possible to return any of data. Streamed data can be pretty handy to return bitmap data from a method. The following is a method that returns a stock history graph for a particular stock over a provided number of years: [CallbackMethod(ContentType="image/png",RouteUrl="stocks/history/graph/{symbol}/{years}")] public Stream GetStockHistoryGraph(string symbol, int years = 2,int width = 500, int height=350) { if (width == 0) width = 500; if (height == 0) height = 350; StockServer server = new StockServer(); return server.GetStockHistoryGraph(symbol,"Stock History for " + symbol,width,height,years); } I can now hook this up into the JavaScript code when I get a stock quote. At the end of the process I can assign the URL to the service that returns the image into the src property and so force the image to display. Here's the changed code: $("#btnStockQuote").click(function () { var symbol = $("#txtSymbol").val(); ajaxCallMethod("SampleService.ashx", "GetStockQuote", [symbol], function (quote) { $("#divStockDisplay").fadeIn(1000); $("#stockCompany").text(quote.Company + " (" + quote.Symbol + ")"); $("#stockLastPrice").text(quote.LastPrice); $("#stockQuoteTime").text(quote.LastQuoteTime.formatDate("MMM dd, hh:mmt")); // display a stock chart $("#imgStockHistory").attr("src", "stocks/history/graph/" + symbol + "/2"); },onPageError); }); The resulting output then looks like this: The charting code uses the new ASP.NET 4.0 Chart components via code to display a bar chart of the 2 year stock data as part of the StockServer class which you can find in the sample download. The ability to return arbitrary data from a service is useful as you can see - in this case the chart is clearly associated with the service and it's nice that the graph generation can happen off a handler rather than through a page. Images are common resources, but output can also be PDF reports, zip files for downloads etc. which is becoming increasingly more common to be returned from REST endpoints and other applications. Why reinvent? Obviously the examples I've shown here are pretty basic in terms of functionality. But I hope they demonstrate the core features of AJAX callbacks that you need to work through in most applications which is simple: return data, send back data and potentially retrieve data in various formats. While there are other solutions when it comes down to making AJAX callbacks and servicing REST like requests, I like the flexibility my home grown solution provides. Simply put it's still the easiest solution that I've found that addresses my common use cases: AJAX JSON RPC style callbacks Url based access XML and JSON Output from single method endpoint XML and JSON POST support, querystring input, routing parameter mapping UrlEncoded POST data support on callbacks Ability to return stream/raw string data Essentially ability to return ANYTHING from Service and pass anything All these features are available in various solutions but not together in one place. I've been using this code base for over 4 years now in a number of projects both for myself and commercial work and it's served me extremely well. Besides the AJAX functionality CallbackHandler provides, it's also an easy way to create any kind of output endpoint I need to create. Need to create a few simple routines that spit back some data, but don't want to create a Page or View or full blown handler for it? Create a CallbackHandler and add a method or multiple methods and you have your generic endpoints.  It's a quick and easy way to add small code pieces that are pretty efficient as they're running through a pretty small handler implementation. I can have this up and running in a couple of minutes literally without any setup and returning just about any kind of data. Resources Download the Sample NuGet: Westwind Web and AJAX Utilities (Westwind.Web) ajaxCallMethod() Documentation Using the AjaxMethodCallback WebForms Control West Wind Web Toolkit Home Page West Wind Web Toolkit Source Code © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  jQuery  AJAX   Tweet (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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