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Plan Caching and Query Memory Part I – When not to use stored procedure or other plan caching mechanisms like sp_executesql or prepared statement

- by sqlworkshops

The most common performance mistake SQL Server developers make: SQL Server estimates memory requirement for queries at compilation time. This mechanism is fine for dynamic queries that need memory, but not for queries that cache the plan. With dynamic queries the plan is not reused for different set of parameters values / predicates and hence different amount of memory can be estimated based on different set of parameter values / predicates. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union. This article covers Sort with examples. It is recommended to read Plan Caching and Query Memory Part II after this article which covers Hash Match operations. When the plan is cached by using stored procedure or other plan caching mechanisms like sp_executesql or prepared statement, SQL Server estimates memory requirement based on first set of execution parameters. Later when the same stored procedure is called with different set of parameter values, the same amount of memory is used to execute the stored procedure. This might lead to underestimation / overestimation of memory on plan reuse, overestimation of memory might not be a noticeable issue for Sort operations, but underestimation of memory will lead to spill over tempdb resulting in poor performance. This article covers underestimation / overestimation of memory for Sort. Plan Caching and Query Memory Part II covers underestimation / overestimation for Hash Match operation. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance. To read additional articles I wrote click here. In most cases it is cheaper to pay for the compilation cost of dynamic queries than huge cost for spill over tempdb, unless memory requirement for a stored procedure does not change significantly based on predicates. The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script. Most of these concepts are also covered in our webcasts: www.sqlworkshops.com/webcasts Enough theory, let’s see an example where we sort initially 1 month of data and then use the stored procedure to sort 6 months of data. Let’s create a stored procedure that sorts customers by name within certain date range. --Example provided by www.sqlworkshops.com create proc CustomersByCreationDate @CreationDateFrom datetime, @CreationDateTo datetime as begin declare @CustomerID int, @CustomerName varchar(48), @CreationDate datetime select @CustomerName = c.CustomerName, @CreationDate = c.CreationDate from Customers c where c.CreationDate between @CreationDateFrom and @CreationDateTo order by c.CustomerName option (maxdop 1) end go Let’s execute the stored procedure initially with 1 month date range. set statistics time on go --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-01-31' go The stored procedure took 48 ms to complete. The stored procedure was granted 6656 KB based on 43199.9 rows being estimated. The estimated number of rows, 43199.9 is similar to actual number of rows 43200 and hence the memory estimation should be ok. There was no Sort Warnings in SQL Profiler. Now let’s execute the stored procedure with 6 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-06-30' go The stored procedure took 679 ms to complete. The stored procedure was granted 6656 KB based on 43199.9 rows being estimated. The estimated number of rows, 43199.9 is way different from the actual number of rows 259200 because the estimation is based on the first set of parameter value supplied to the stored procedure which is 1 month in our case. This underestimation will lead to sort spill over tempdb, resulting in poor performance. There was Sort Warnings in SQL Profiler. To monitor the amount of data written and read from tempdb, one can execute select num_of_bytes_written, num_of_bytes_read from sys.dm_io_virtual_file_stats(2, NULL) before and after the stored procedure execution, for additional information refer to the webcast: www.sqlworkshops.com/webcasts. Let’s recompile the stored procedure and then let’s first execute the stored procedure with 6 month date range. In a production instance it is not advisable to use sp_recompile instead one should use DBCC FREEPROCCACHE (plan_handle). This is due to locking issues involved with sp_recompile, refer to our webcasts for further details. exec sp_recompile CustomersByCreationDate go --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-06-30' go Now the stored procedure took only 294 ms instead of 679 ms. The stored procedure was granted 26832 KB of memory. The estimated number of rows, 259200 is similar to actual number of rows of 259200. Better performance of this stored procedure is due to better estimation of memory and avoiding sort spill over tempdb. There was no Sort Warnings in SQL Profiler. Now let’s execute the stored procedure with 1 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-01-31' go The stored procedure took 49 ms to complete, similar to our very first stored procedure execution. This stored procedure was granted more memory (26832 KB) than necessary memory (6656 KB) based on 6 months of data estimation (259200 rows) instead of 1 month of data estimation (43199.9 rows). This is because the estimation is based on the first set of parameter value supplied to the stored procedure which is 6 months in this case. This overestimation did not affect performance, but it might affect performance of other concurrent queries requiring memory and hence overestimation is not recommended. This overestimation might affect performance Hash Match operations, refer to article Plan Caching and Query Memory Part II for further details. Let’s recompile the stored procedure and then let’s first execute the stored procedure with 2 day date range. exec sp_recompile CustomersByCreationDate go --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-01-02' go The stored procedure took 1 ms. The stored procedure was granted 1024 KB based on 1440 rows being estimated. There was no Sort Warnings in SQL Profiler. Now let’s execute the stored procedure with 6 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-06-30' go The stored procedure took 955 ms to complete, way higher than 679 ms or 294ms we noticed before. The stored procedure was granted 1024 KB based on 1440 rows being estimated. But we noticed in the past this stored procedure with 6 month date range needed 26832 KB of memory to execute optimally without spill over tempdb. This is clear underestimation of memory and the reason for the very poor performance. There was Sort Warnings in SQL Profiler. Unlike before this was a Multiple pass sort instead of Single pass sort. This occurs when granted memory is too low. Intermediate Summary: This issue can be avoided by not caching the plan for memory allocating queries. Other possibility is to use recompile hint or optimize for hint to allocate memory for predefined date range. Let’s recreate the stored procedure with recompile hint. --Example provided by www.sqlworkshops.com drop proc CustomersByCreationDate go create proc CustomersByCreationDate @CreationDateFrom datetime, @CreationDateTo datetime as begin declare @CustomerID int, @CustomerName varchar(48), @CreationDate datetime select @CustomerName = c.CustomerName, @CreationDate = c.CreationDate from Customers c where c.CreationDate between @CreationDateFrom and @CreationDateTo order by c.CustomerName option (maxdop 1, recompile) end go Let’s execute the stored procedure initially with 1 month date range and then with 6 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-01-30' exec CustomersByCreationDate '2001-01-01', '2001-06-30' go The stored procedure took 48ms and 291 ms in line with previous optimal execution times. The stored procedure with 1 month date range has good estimation like before. The stored procedure with 6 month date range also has good estimation and memory grant like before because the query was recompiled with current set of parameter values. The compilation time and compilation CPU of 1 ms is not expensive in this case compared to the performance benefit. Let’s recreate the stored procedure with optimize for hint of 6 month date range. --Example provided by www.sqlworkshops.com drop proc CustomersByCreationDate go create proc CustomersByCreationDate @CreationDateFrom datetime, @CreationDateTo datetime as begin declare @CustomerID int, @CustomerName varchar(48), @CreationDate datetime select @CustomerName = c.CustomerName, @CreationDate = c.CreationDate from Customers c where c.CreationDate between @CreationDateFrom and @CreationDateTo order by c.CustomerName option (maxdop 1, optimize for (@CreationDateFrom = '2001-01-01', @CreationDateTo ='2001-06-30')) end go Let’s execute the stored procedure initially with 1 month date range and then with 6 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-01-30' exec CustomersByCreationDate '2001-01-01', '2001-06-30' go The stored procedure took 48ms and 291 ms in line with previous optimal execution times. The stored procedure with 1 month date range has overestimation of rows and memory. This is because we provided hint to optimize for 6 months of data. The stored procedure with 6 month date range has good estimation and memory grant because we provided hint to optimize for 6 months of data. Let’s execute the stored procedure with 12 month date range using the currently cashed plan for 6 month date range. --Example provided by www.sqlworkshops.com exec CustomersByCreationDate '2001-01-01', '2001-12-31' go The stored procedure took 1138 ms to complete. 2592000 rows were estimated based on optimize for hint value for 6 month date range. Actual number of rows is 524160 due to 12 month date range. The stored procedure was granted enough memory to sort 6 month date range and not 12 month date range, so there will be spill over tempdb. There was Sort Warnings in SQL Profiler. As we see above, optimize for hint cannot guarantee enough memory and optimal performance compared to recompile hint. This article covers underestimation / overestimation of memory for Sort. Plan Caching and Query Memory Part II covers underestimation / overestimation for Hash Match operation. It is important to note that underestimation of memory for Sort and Hash Match operations lead to spill over tempdb and hence negatively impact performance. Overestimation of memory affects the memory needs of other concurrently executing queries. In addition, it is important to note, with Hash Match operations, overestimation of memory can actually lead to poor performance. Summary: Cached plan might lead to underestimation or overestimation of memory because the memory is estimated based on first set of execution parameters. It is recommended not to cache the plan if the amount of memory required to execute the stored procedure has a wide range of possibilities. One can mitigate this by using recompile hint, but that will lead to compilation overhead. However, in most cases it might be ok to pay for compilation rather than spilling sort over tempdb which could be very expensive compared to compilation cost. The other possibility is to use optimize for hint, but in case one sorts more data than hinted by optimize for hint, this will still lead to spill. On the other side there is also the possibility of overestimation leading to unnecessary memory issues for other concurrently executing queries. In case of Hash Match operations, this overestimation of memory might lead to poor performance. When the values used in optimize for hint are archived from the database, the estimation will be wrong leading to worst performance, so one has to exercise caution before using optimize for hint, recompile hint is better in this case. I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts. Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here. Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk. R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan

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PTLQueue : a scalable bounded-capacity MPMC queue

- by Dave

Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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Informed TDD – Kata “To Roman Numerals”

- 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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iPhone SDK vs. Windows Phone 7 Series SDK Challenge, Part 2: MoveMe

In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series. My goal is to do as much of an apples-to-apples comparison as I can. This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. If youre seeing this series for the first time, check out Part 1: Hello World. A note on methodologyin the prior post there was some feedback about lines of code not being a very good metric for this exercise. I dont really disagree, theres a lot more to this than lines of code but I believe that is a relevant metric, even if its not the ultimate one. And theres no perfect answer here. So I am going to continue to report the number of lines of code that I, as a developer would need to write in these apps as a data point, and Ill leave it up to the reader to determine how that fits in with overall complexity, etc. The first example was so basic that I think it was difficult to talk about in real terms. I think that as these apps get more complex, the subjective differences in concept count and will be more important. MoveMe The MoveMe app is the main end-to-end app writing example in the iPhone SDK, called Creating an iPhone Application. This application demonstrates a few concepts, including handling touch input, how to do animations, and how to do some basic transforms. The behavior of the application is pretty simple. User touches the button: The button does a throb type animation where it scales up and then back down briefly. User drags the button: After a touch begins, moving the touch point will drag the button around with the touch. User lets go of the button: The button animates back to its original position, but does a few small bounces as it reaches its original point, which makes the app fun and gives it an extra bit of interactivity. Now, how would I write an app that meets this spec for Windows Phone 7 Series, and how hard would it be? Lets find out! Implementing the UI Okay, lets build the UI for this application. In the HelloWorld example, we did all the UI design in Visual Studio and/or by hand in XAML. In this example, were going to use the Expression Blend 4 Beta. You might be wondering when to use Visual Studio, when to use Blend, and when to do XAML by hand. Different people will have different takes on this, but heres mine: XAML by hand simple UI that doesnt contain animations, gradients, etc., and or UI that I want to really optimize and craft when I know exactly what I want to do. Visual Studio Basic UI layout, property setting, data binding, etc. Blend Any serious design work needs to be done in Blend, including animations, handling states and transitions, styling and templating, editing resources. As in Part 1, go ahead and fire up Visual Studio 2010 Express for Windows Phone (yes, soon it will take longer to say the name of our products than to start them up!), and create a new Windows Phone Application. As in Part 1, clear out the XAML from the designer. An easy way to do this is to just: Click on the design surface Hit Control+A Hit Delete Theres a little bit left over (the Grid.RowDefinitions element), just go ahead and delete that element so were starting with a clean state of only one outer Grid element. To use Blend, we need to save this project. See, when you create a project with Visual Studio Express, it doesnt commit it to the disk (well, in a place where you can find it, at least) until you actually save the project. This is handy if youre doing some fooling around, because it doesnt clutter your disk with WindowsPhoneApplication23-like directories. But its also kind of dangerous, since when you close VS, if you dont save the projectits all gone. Yes, this has bitten me since I was saving files and didnt remember that, so be careful to save the project/solution via Save All, at least once. So, save and note the location on disk. Start Expression Blend 4 Beta, and chose File > Open Project/Solution, and load your project. You should see just about the same thing you saw over in VS: a blank, black designer surface. Now, thinking about this application, we dont really need a button, even though it looks like one. We never click it. So were just going to create a visual and use that. This is also true in the iPhone example above, where the visual is actually not a button either but a jpg image with a nice gradient and round edges. Well do something simple here that looks pretty good. In Blend, look in the tool pane on the left for the icon that looks like the below (the highlighted one on the left), and hold it down to get the popout menu, and choose Border: Okay, now draw out a box in the middle of the design surface of about 300x100. The Properties Pane to the left should show the properties for this item. First, lets make it more visible by giving it a border brush. Set the BorderBrush to white by clicking BorderBrush and dragging the color selector all the way to the upper right in the palette. Then, down a bit farther, make the BorderThickness 4 all the way around, and the CornerRadius set to 6. In the Layout section, do the following to Width, Height, Horizontal and Vertical Alignment, and Margin (all 4 margin values): Youll see the outline now is in the middle of the design surface. Now lets give it a background color. Above BorderBrush select Background, and click the third tab over: Gradient Brush. Youll see a gradient slider at the bottom, and if you click the markers, you can edit the gradient stops individually (or add more). In this case, you can select something you like, but wheres what I chose: Left stop: #BFACCFE2 (I just picked a spot on the palette and set opacity to 75%, no magic here, feel free to fiddle these or just enter these numbers into the hex area and be done with it) Right stop: #FF3E738F Okay, looks pretty good. Finally set the name of the element in the Name field at the top of the Properties pane to welcome. Now lets add some text. Just hit T and itll select the TextBlock tool automatically: Now draw out some are inside our welcome visual and type Welcome!, then click on the design surface (to exit text entry mode) and hit V to go back into selection mode (or the top item in the tool pane that looks like a mouse pointer). Click on the text again to select it in the tool pane. Just like the border, we want to center this. So set HorizontalAlignment and VerticalAlignment to Center, and clear the Margins: Thats it for the UI. Heres how it looks, on the design surface: Not bad! Okay, now the fun part Adding Animations Using Blend to build animations is a lot of fun, and its easy. In XAML, I can not only declare elements and visuals, but also I can declare animations that will affect those visuals. These are called Storyboards. To recap, well be doing two animations: The throb animation when the element is touched The center animation when the element is released after being dragged. The throb animation is just a scale transform, so well do that first. In the Objects and Timeline Pane (left side, bottom half), click the little + icon to add a new Storyboard called touchStoryboard: The timeline view will appear. In there, click a bit to the right of 0 to create a keyframe at .2 seconds: Now, click on our welcome element (the Border, not the TextBlock in it), and scroll to the bottom of the Properties Pane. Open up Transform, click the third tab ("Scale), and set X and Y to 1.2: This all of this says that, at .2 seconds, I want the X and Y size of this element to scale to 1.2. In fact you can see this happen. Push the Play arrow in the timeline view, and youll see the animation run! Lets make two tweaks. First, we want the animation to automatically reverse so it scales up then back down nicely. Click in the dropdown that says touchStoryboard in Objects and Timeline, then in the Properties pane check Auto Reverse: Now run it again, and youll see it go both ways. Lets even make it nicer by adding an easing function. First, click on the Render Transform item in the Objects tree, then, in the Property Pane, youll see a bunch of easing functions to choose from. Feel free to play with this, then seeing how each runs. I chose Circle In, but some other ones are fun. Try them out! Elastic In is kind of fun, but well stick with Circle In. Thats it for that animation. Now, we also want an animation to move the Border back to its original position when the user ends the touch gesture. This is exactly the same process as above, but just targeting a different transform property. Create a new animation called releaseStoryboard Select a timeline point at 1.2 seconds. Click on the welcome Border element again Scroll to the Transforms panel at the bottom of the Properties Pane Choose the first tab (Translate), which may already be selected Set both X and Y values to 0.0 (we do this just to make the values stick, because the value is already 0 and we need Blend to know we want to save that value) Click on RenderTransform in the Objects tree In the properties pane, choose Bounce Out Set Bounces to 6, and Bounciness to 4 (feel free to play with these as well) Okay, were done. Note, if you want to test this Storyboard, you have to do something a little tricky because the final value is the same as the initial value, so playing it does nothing. If you want to play with it, do the following: Next to the selection dropdown, hit the little "x (Close Storyboard) Go to the Translate Transform value for welcome Set X,Y to 50, 200, respectively (or whatever) Select releaseStoryboard again from the dropdown Hit play, see it run Go into the object tree and select RenderTransform to change the easing function. When youre done, hit the Close Storyboard x again and set the values in Transform/Translate back to 0 Wiring Up the Animations Okay, now go back to Visual Studio. Youll get a prompt due to the modification of MainPage.xaml. Hit Yes. In the designer, click on the welcome Border element. In the Property Browser, hit the Events button, then double click each of ManipulationStarted, ManipulationDelta, ManipulationCompleted. Youll need to flip back to the designer from code, after each double click. Its code time. Here we go. Here, three event handlers have been created for us: welcome_ManipulationStarted: This will execute when a manipulation begins. Think of it as MouseDown. welcome_ManipulationDelta: This executes each time a manipulation changes. Think MouseMove. welcome_ManipulationCompleted: This will execute when the manipulation ends. Think MouseUp. Now, in ManipuliationStarted, we want to kick off the throb animation that we called touchAnimation. Thats easy: 1: private void welcome_ManipulationStarted(object sender, ManipulationStartedEventArgs e) 2: { 3: touchStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Likewise, when the manipulation completes, we want to re-center the welcome visual with our bounce animation: 1: private void welcome_ManipulationCompleted(object sender, ManipulationCompletedEventArgs e) 2: { 3: releaseStoryboard.Begin(); 4: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Note there is actually a way to kick off these animations from Blend directly via something called Triggers, but I think its clearer to show whats going on like this. A Trigger basically allows you to say When this event fires, trigger this Storyboard, so its the exact same logical process as above, but without the code. But how do we get the object to move? Well, for that we really dont want an animation because we want it to respond immediately to user input. We do this by directly modifying the transform to match the offset for the manipulation, and then well let the animation bring it back to zero when the manipulation completes. The manipulation events do a great job of keeping track of all the stuff that you usually had to do yourself when doing drags: where you started from, how far youve moved, etc. So we can easily modify the position as below: 1: private void welcome_ManipulationDelta(object sender, ManipulationDeltaEventArgs e) 2: { 3: CompositeTransform transform = (CompositeTransform)welcome.RenderTransform; 4: 5: transform.TranslateX = e.CumulativeManipulation.Translation.X; 6: transform.TranslateY = e.CumulativeManipulation.Translation.Y; 7: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Thats it! Go ahead and run the app in the emulator. I suggest running without the debugger, its a little faster (CTRL+F5). If youve got a machine that supports DirectX 10, youll see nice smooth GPU accelerated graphics, which also what it looks like on the phone, running at about 60 frames per second. If your machine does not support DX10 (like the laptop Im writing this on!), it wont be quite a smooth so youll have to take my word for it! Comparing Against the iPhone This is an example where the flexibility and power of XAML meets the tooling of Visual Studio and Blend, and the whole experience really shines. So, for several things that are declarative and 100% toolable with the Windows Phone 7 Series, this example does them with code on the iPhone. In parens is the lines of code that I count to do these operations. PlacardView.m: 19 total LOC Creating the view that hosts the button-like image and the text Drawing the image that is the background of the button Drawing the Welcome text over the image (I think you could technically do this step and/or the prior one using Interface Builder) MoveMeView.m: 63 total LOC Constructing and running the scale (throb) animation (25) Constructing the path describing the animation back to center plus bounce effect (38) Beyond the code count, yy experience with doing this kind of thing in code is that its VERY time intensive. When I was a developer back on Windows Forms, doing GDI+ drawing, we did this stuff a lot, and it took forever! You write some code and even once you get it basically working, you see its not quite right, you go back, tweak the interval, or the math a bit, run it again, etc. You can take a look at the iPhone code here to judge for yourself. Scroll down to animatePlacardViewToCenter toward the bottom. I dont think this code is terribly complicated, but its not what Id call simple and its not at all simple to get right. And then theres a few other lines of code running around for setting up the ViewController and the Views, about 15 lines between MoveMeAppDelegate, PlacardView, and MoveMeView, plus the assorted decls in the h files. Adding those up, I conservatively get something like 100 lines of code (19+63+15+decls) on iPhone that I have to write, by hand, to make this project work. The lines of code that I wrote in the examples above is 5 lines of code on Windows Phone 7 Series. In terms of incremental concept counts beyond the HelloWorld app, heres a shot at that: iPhone: Drawing Images Drawing Text Handling touch events Creating animations Scaling animations Building a path and animating along that Windows Phone 7 Series: Laying out UI in Blend Creating & testing basic animations in Blend Handling touch events Invoking animations from code This was actually the first example I tried converting, even before I did the HelloWorld, and I was pretty surprised. Some of this is luck that this app happens to match up with the Windows Phone 7 Series platform just perfectly. In terms of time, I wrote the above application, from scratch, in about 10 minutes. I dont know how long it would take a very skilled iPhone developer to write MoveMe on that iPhone from scratch, but if I was to write it on Silverlight in the same way (e.g. all via code), I think it would likely take me at least an hour or two to get it all working right, maybe more if I ended up picking the wrong strategy or couldnt get the math right, etc. Making Some Tweaks Silverlight contains a feature called Projections to do a variety of 3D-like effects with a 2D surface. So lets play with that a bit. Go back to Blend and select the welcome Border in the object tree. In its properties, scroll down to the bottom, open Transform, and see Projection at the bottom. Set X,Y,Z to 90. Youll see the element kind of disappear, replaced by a thin blue line. Now Create a new animation called startupStoryboard. Set its key time to .5 seconds in the timeline view Set the projection values above to 0 for X, Y, and Z. Save Go back to Visual Studio, and in the constructor, add the following bold code (lines 7-9 to the constructor: 1: public MainPage() 2: { 3: InitializeComponent(); 4: 5: SupportedOrientations = SupportedPageOrientation.Portrait; 6: 7: this.Loaded += (s, e) => 8: { 9: startupStoryboard.Begin(); 10: }; 11: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If the code above looks funny, its using something called a lambda in C#, which is an inline anonymous method. Its just a handy shorthand for creating a handler like the manipulation ones above. So with this youll get a nice 3D looking fly in effect when the app starts up. Here it is, in flight: Pretty cool!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Partner Blog Series: PwC Perspectives - The Gotchas, The Do's and Don'ts for IDM Implementations

- by Tanu Sood

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mso-tstyle-border-bottom-themecolor:accent6; font-family:"Arial Narrow","sans-serif"; mso-ascii-font-family:Georgia; mso-ascii-theme-font:major-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:major-fareast; mso-hansi-font-family:Georgia; mso-hansi-theme-font:major-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:major-bidi;} table.MsoTableMediumList1Accent6LastRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; color:#968C6D; mso-themecolor:text2; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6FirstCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-column; mso-style-priority:65; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6LastCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6OddColumn {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} table.MsoTableMediumList1Accent6OddRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} It is generally accepted among business communities that technology by itself is not a silver bullet to all problems, but when it is combined with leading practices, strategy, careful planning and execution, it can create a recipe for success. This post attempts to highlight some of the best practices along with dos & don’ts that our practice has accumulated over the years in the identity & access management space in general, and also in the context of R2, in particular. Best Practices The following section illustrates the leading practices in “How” to plan, implement and sustain a successful OIM deployment, based on our collective experience. Planning is critical, but often overlooked A common approach to planning an IAM program that we identify with our clients is the three step process involving a current state assessment, a future state roadmap and an executable strategy to get there. It is extremely beneficial for clients to assess their current IAM state, perform gap analysis, document the recommended controls to address the gaps, align future state roadmap to business initiatives and get buy in from all stakeholders involved to improve the chances of success. When designing an enterprise-wide solution, the scalability of the technology must accommodate the future growth of the enterprise and the projected identity transactions over several years. Aligning the implementation schedule of OIM to related information technology projects increases the chances of success. As a baseline, it is recommended to match hardware specifications to the sizing guide for R2 published by Oracle. Adherence to this will help ensure that the hardware used to support OIM will not become a bottleneck as the adoption of new services increases. If your Organization has numerous connected applications that rely on reconciliation to synchronize the access data into OIM, consider hosting dedicated instances to handle reconciliation. Finally, ensure the use of clustered environment for development and have at least three total environments to help facilitate a controlled migration to production. If your Organization is planning to implement role based access control, we recommend performing a role mining exercise and consolidate your enterprise roles to keep them manageable. In addition, many Organizations have multiple approval flows to control access to critical roles, applications and entitlements. If your Organization falls into this category, we highly recommend that you limit the number of approval workflows to a small set. Most Organizations have operations managed across data centers with backend database synchronization, if your Organization falls into this category, ensure that the overall latency between the datacenters when replicating the databases is less than ten milliseconds to ensure that there are no front office performance impacts. Ingredients for a successful implementation During the development phase of your project, there are a number of guidelines that can be followed to help increase the chances for success. Most implementations cannot be completed without the use of customizations. If your implementation requires this, it’s a good practice to perform code reviews to help ensure quality and reduce code bottlenecks related to performance. We have observed at our clients that the development process works best when team members adhere to coding leading practices. Plan for time to correct coding defects and ensure developers are empowered to report their own bugs for maximum transparency. Many organizations struggle with defining a consistent approach to managing logs. This is particularly important due to the amount of information that can be logged by OIM. We recommend Oracle Diagnostics Logging (ODL) as an alternative to be used for logging. ODL allows log files to be formatted in XML for easy parsing and does not require a server restart when the log levels are changed during troubleshooting. Testing is a vital part of any large project, and an OIM R2 implementation is no exception. We suggest that at least one lower environment should use production-like data and connectors. Configurations should match as closely as possible. For example, use secure channels between OIM and target platforms in pre-production environments to test the configurations, the migration processes of certificates, and the additional overhead that encryption could impose. Finally, we ask our clients to perform database backups regularly and before any major change event, such as a patch or migration between environments. In the lowest environments, we recommend to have at least a weekly backup in order to prevent significant loss of time and effort. Similarly, if your organization is using virtual machines for one or more of the environments, it is recommended to take frequent snapshots so that rollbacks can occur in the event of improper configuration. Operate & sustain the solution to derive maximum benefits When migrating OIM R2 to production, it is important to perform certain activities that will help achieve a smoother transition. At our clients, we have seen that splitting the OIM tables into their own tablespaces by categories (physical tables, indexes, etc.) can help manage database growth effectively. If we notice that a client hasn’t enabled the Oracle-recommended indexing in the applicable database, we strongly suggest doing so to improve performance. Additionally, we work with our clients to make sure that the audit level is set to fit the organization’s auditing needs and sometimes even allocate UPA tables and indexes into their own table-space for better maintenance. Finally, many of our clients have set up schedules for reconciliation tables to be archived at regular intervals in order to keep the size of the database(s) reasonable and result in optimal database performance. For our clients that anticipate availability issues with target applications, we strongly encourage the use of the offline provisioning capabilities of OIM R2. This reduces the provisioning process for a given target application dependency on target availability and help avoid broken workflows. To account for this and other abnormalities, we also advocate that OIM’s monitoring controls be configured to alert administrators on any abnormal situations. Within OIM R2, we have begun advising our clients to utilize the ‘profile’ feature to encapsulate multiple commonly requested accounts, roles, and/or entitlements into a single item. By setting up a number of profiles that can be searched for and used, users will spend less time performing the same exact steps for common tasks. We advise our clients to follow the Oracle recommended guides for database and application server tuning which provides a good baseline configuration. It offers guidance on database connection pools, connection timeouts, user interface threads and proper handling of adapters/plug-ins. All of these can be important configurations that will allow faster provisioning and web page response times. Many of our clients have begun to recognize the value of data mining and a remediation process during the initial phases of an implementation (to help ensure high quality data gets loaded) and beyond (to support ongoing maintenance and business-as-usual processes). A successful program always begins with identifying the data elements and assigning a classification level based on criticality, risk, and availability. It should finish by following through with a remediation process. Dos & Don’ts Here are the most common dos and don'ts that we socialize with our clients, derived from our experience implementing the solution. Dos Don’ts Scope the project into phases with realistic goals. Look for quick wins to show success and value to the stake holders. Avoid “boiling the ocean” and trying to integrate all enterprise applications in the first phase. Establish an enterprise ID (universal unique ID across the enterprise) earlier in the program. Avoid major UI customizations that require code changes. Have a plan in place to patch during the project, which helps alleviate any major issues or roadblocks (product and database). Avoid publishing all the target entitlements if you don't anticipate their usage during access request. Assess your current state and prepare a roadmap to address your operations, tactical and strategic goals, align it with your business priorities. Avoid integrating non-production environments with your production target systems. Defer complex integrations to the later phases and take advantage of lessons learned from previous phases Avoid creating multiple accounts for the same user on the same system, if there is an opportunity to do so. Have an identity and access data quality initiative built into your plan to identify and remediate data related issues early on. Avoid creating complex approval workflows that would negative impact productivity and SLAs. Identify the owner of the identity systems with fair IdM knowledge and empower them with authority to make product related decisions. This will help ensure overcome any design hurdles. Avoid creating complex designs that are not sustainable long term and would need major overhaul during upgrades. Shadow your internal or external consulting resources during the implementation to build the necessary product skills needed to operate and sustain the solution. Avoid treating IAM as a point solution and have appropriate level of communication and training plan for the IT and business users alike. Conclusion In our experience, Identity programs will struggle with scope, proper resourcing, and more. We suggest that companies consider the suggestions discussed in this post and leverage them to help enable their identity and access program. This concludes PwC blog series on R2 for the month and we sincerely hope that the information we have shared thus far has been beneficial. For more information or if you have questions, you can reach out to Rex Thexton, Senior Managing Director, PwC and or Dharma Padala, Director, PwC. We look forward to hearing from you. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:12.0pt; mso-para-margin-left:0in; line-height:12.0pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Arial","sans-serif"; mso-ascii-font-family:Arial; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Meet the Writers: Dharma Padala is a Director in the Advisory Security practice within PwC. He has been implementing medium to large scale Identity Management solutions across multiple industries including utility, health care, entertainment, retail and financial sectors. Dharma has 14 years of experience in delivering IT solutions out of which he has been implementing Identity Management solutions for the past 8 years. Praveen Krishna is a Manager in the Advisory Security practice within PwC. Over the last decade Praveen has helped clients plan, architect and implement Oracle identity solutions across diverse industries. His experience includes delivering security across diverse topics like network, infrastructure, application and data where he brings a holistic point of view to problem solving. Scott MacDonald is a Director in the Advisory Security practice within PwC. He has consulted for several clients across multiple industries including financial services, health care, automotive and retail. Scott has 10 years of experience in delivering Identity Management solutions. John Misczak is a member of the Advisory Security practice within PwC. He has experience implementing multiple Identity and Access Management solutions, specializing in Oracle Identity Manager and Business Process Engineering Language (BPEL).

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Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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Why can't I assign a scalar value to a class using shorthand, but instead declare it first, then set

- by ~delan-azabani

I am writing a UTF-8 library for C++ as an exercise as this is my first real-world C++ code. So far, I've implemented concatenation, character indexing, parsing and encoding UTF-8 in a class called "ustring". It looks like it's working, but two (seemingly equivalent) ways of declaring a new ustring behave differently. The first way: ustring a; a = "test"; works, and the overloaded "=" operator parses the string into the class (which stores the Unicode strings as an dynamically allocated int pointer). However, the following does not work: ustring a = "test"; because I get the following error: test.cpp:4: error: conversion from ‘const char [5]’ to non-scalar type ‘ustring’ requested Is there a way to workaround this error? It probably is a problem with my code, though. The following is what I've written so far for the library: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring * operator=(ustring input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; return this; } ustring * operator=(char input[]) { len = sizeof(input); values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; i < sizeof(input); i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } return this; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

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Problem with java and conditional (game of life)

- by Muad'Dib

Hello everybody, I'm trying to implement The Game of Life in java, as an exercise to learn this language. Unfortunately I have a problem, as I don't seem able to make this program run correctly. I implemented a torodial sum (the plane is a donut) with no problem: int SumNeighbours (int i, int j) { int value = 0; value = world[( i - 1 + row ) % row][( j - 1 + column ) % column]+world[( i - 1 + row ) % row][j]+world[( i - 1 + row ) % row][( j + 1 ) % column]; value = value + world[i][( j - 1 + column ) % column] + world[i][( j + 1 ) % column]; value = value + world[( i + 1 ) % row][( j - 1 + column ) % column] + world[( i + 1 ) % row][j]+world[ ( i+1 ) % row ][( j + 1 ) % column]; return value; } And it sums correctly when I test it: void NextWorldTest () { int count; int [][] nextWorld = new int[row][row]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); } System.out.println(); } world=nextWorld; } Unfortunately when I add the conditions of game of life (born/death) the program stop working correctly, as it seems not able anymore to count correctly the alive cells in the neighborhood. It counts where there are none, and it doesn't count when there are some. E.g.: it doesn't count the one below some living cells. It's a very odd behaviour, and it's been giving me a headache for 3 days now... maybe I'm missing something basic about variables? Here you can find the class. void NextWorld () { int count; int [][] nextWorld = new int[row][column]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); if ( ( world[i][j] == 0) && ( count == 3 ) ) { nextWorld[i][j] = 1; } else if ( ( world[i][j] == 1 ) && ( (count == 3) || (count == 2) )) { nextWorld[i][j] = 1; } else { nextWorld[i][j]=0; } } System.out.println(); } world=nextWorld; } } Am I doing something wrong? Below you can find the full package. package com.GaOL; public class GameWorld { int [][] world; int row; int column; public int GetRow() { return row; } public int GetColumn() { return column; } public int GetWorld (int i, int j) { return world[i][j]; } void RandomGen (int size, double p1) { double randomCell; row = size; column = size; world = new int[row][column]; for (int i = 0; i<row; i++ ) { for (int j = 0; j<column; j++ ) { randomCell=Math.random(); if (randomCell < 1-p1) { world[i][j] = 0; } else { world[i][j] = 1; } } } } void printToConsole() { double test = 0; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { if ( world[i][j] == 0 ) { System.out.print(" "); } else { System.out.print(" * "); test++; } } System.out.println(""); } System.out.println("ratio is " + test/(row*column)); } int SumNeighbours (int i, int j) { int value = 0; value = world[( i - 1 + row ) % row][( j - 1 + column ) % column]+world[( i - 1 + row ) % row][j]+world[( i - 1 + row ) % row][( j + 1 ) % column]; value = value + world[i][( j - 1 + column ) % column] + world[i][( j + 1 ) % column]; value = value + world[( i + 1 ) % row][( j - 1 + column ) % column] + world[( i + 1 ) % row][j]+world[ ( i+1 ) % row ][( j + 1 ) % column]; return value; } void NextWorldTest () { int count; int [][] nextWorld = new int[row][row]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); } System.out.println(); } world=nextWorld; } void NextWorld () { int count; int [][] nextWorld = new int[row][column]; nextWorld = world; for (int i=0; i<row; i++) { for (int j=0; j<column; j++) { count = SumNeighbours(i,j); System.out.print(" " + count + " "); if ( ( world[i][j] == 0) && ( count == 3 ) ) { nextWorld[i][j] = 1; } else if ( ( world[i][j] == 1 ) && ( (count == 3) || (count == 2) )) { nextWorld[i][j] = 1; } else { nextWorld[i][j]=0; } } System.out.println(); } world=nextWorld; } } and here the test class: package com.GaOL; public class GameTestClass { public static void main(String[] args) { GameWorld prova = new GameWorld(); prova.RandomGen(10, 0.02); for (int i=0; i<3; i++) { prova.printToConsole(); prova.NextWorld(); } } }

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Returning a list from a function in Python

- by Jasper

Hi, I'm creating a game for my sister, and I want a function to return a list variable, so I can pass it to another variable. The relevant code is as follows: def startNewGame(): while 1: #Introduction: print print """Hello, You will now be guided through the setup process. There are 7 steps to this. You can cancel setup at any time by typing 'cancelSetup' Thankyou""" #Step 1 (Name): print print """Step 1 of 7: Type in a name for your PotatoHead: """ inputPHName = raw_input('|Enter Name:|') if inputPHName == 'cancelSetup': sys.exit() #Step 2 (Gender): print print """Step 2 of 7: Choose the gender of your PotatoHead: input either 'm' or 'f' """ inputPHGender = raw_input('|Enter Gender:|') if inputPHGender == 'cancelSetup': sys.exit() #Step 3 (Colour): print print """Step 3 of 7: Choose the colour your PotatoHead will be: Only Red, Blue, Green and Yellow are currently supported """ inputPHColour = raw_input('|Enter Colour:|') if inputPHColour == 'cancelSetup': sys.exit() #Step 4 (Favourite Thing): print print """Step 4 of 7: Type your PotatoHead's favourite thing: """ inputPHFavThing = raw_input('|Enter Favourite Thing:|') if inputPHFavThing == 'cancelSetup': sys.exit() # Step 5 (First Toy): print print """Step 5 of 7: Choose a first toy for your PotatoHead: """ inputPHFirstToy = raw_input('|Enter First Toy:|') if inputPHFirstToy == 'cancelSetup': sys.exit() #Step 6 (Check stats): while 1: print print """Step 6 of 7: Check the following details to make sure that they are correct: """ print print """Name:\t\t\t""" + inputPHName + """ Gender:\t\t\t""" + inputPHGender + """ Colour:\t\t\t""" + inputPHColour + """ Favourite Thing:\t""" + inputPHFavThing + """ First Toy:\t\t""" + inputPHFirstToy + """ """ print print "Enter 'y' or 'n'" inputMCheckStats = raw_input('|Is this information correct?|') if inputMCheckStats == 'cancelSetup': sys.exit() elif inputMCheckStats == 'y': break elif inputMCheckStats == 'n': print "Re-enter info: ..." print break else: "The value you entered was incorrect, please re-enter your choice" if inputMCheckStats == 'y': break #Step 7 (Define variables for the creation of the PotatoHead): MFCreatePH = [] print print """Step 7 of 7: Your PotatoHead will now be created... Creating variables... """ MFCreatePH = [inputPHName, inputPHGender, inputPHColour, inputPHFavThing, inputPHFirstToy] time.sleep(1) print "inputPHName" print time.sleep(1) print "inputPHFirstToy" print return MFCreatePH print "Your PotatoHead varibles have been successfully created!" Then it is passed to another function that was imported from another module from potatohead import * ... welcomeMessage() MCreatePH = startGame() myPotatoHead = PotatoHead(MCreatePH) the code for the PotatoHead object is in the potatohead.py module which was imported above, and is as follows: class PotatoHead: #Initialise the PotatoHead object: def __init__(self, data): self.data = data #Takes the data from the start new game function - see main.py #Defines the PotatoHead starting attributes: self.name = data[0] self.gender = data[1] self.colour = data[2] self.favouriteThing = data[3] self.firstToy = data[4] self.age = '0.0' self.education = [self.eduScience, self.eduEnglish, self.eduMaths] = '0.0', '0.0', '0.0' self.fitness = '0.0' self.happiness = '10.0' self.health = '10.0' self.hunger = '0.0' self.tiredness = 'Not in this version' self.toys = [] self.toys.append(self.firstToy) self.time = '0' #Sets data lists for saving, loading and general use: self.phData = (self.name, self.gender, self.colour, self.favouriteThing, self.firstToy) self.phAdvData = (self.name, self.gender, self.colour, self.favouriteThing, self.firstToy, self.age, self.education, self.fitness, self.happiness, self.health, self.hunger, self.tiredness, self.toys) However, when I run the program this error appears: Traceback (most recent call last): File "/Users/Jasper/Documents/Programming/Potato Head Game/Current/main.py", line 158, in <module> myPotatoHead = PotatoHead(MCreatePH) File "/Users/Jasper/Documents/Programming/Potato Head Game/Current/potatohead.py", line 15, in __init__ self.name = data[0] TypeError: 'NoneType' object is unsubscriptable What am i doing wrong? -----EDIT----- The program finishes as so: Step 7 of 7: Your PotatoHead will now be created... Creating variables... inputPHName inputPHFirstToy Then it goes to the Tracback -----EDIT2----- This is the EXACT code I'm running in its entirety: #+--------------------------------------+# #| main.py |# #| A main module for the Potato Head |# #| Game to pull the other modules |# #| together and control through user |# #| input |# #| Author: |# #| Date Created / Modified: |# #| 3/2/10 | 20/2/10 |# #+--------------------------------------+# Tested: No #Import the required modules: import time import random import sys from potatohead import * from toy import * #Start the Game: def welcomeMessage(): print "----- START NEW GAME -----------------------" print "==Print Welcome Message==" print "loading... \t loading... \t loading..." time.sleep(1) print "loading..." time.sleep(1) print "LOADED..." print; print; print; print """Hello, Welcome to the Potato Head Game. In this game you can create a Potato Head, and look after it, like a Virtual Pet. This game is constantly being updated and expanded. Please look out for updates. """ #Choose whether to start a new game or load a previously saved game: def startGame(): while 1: print "--------------------" print """ Choose an option: New_Game or Load_Game """ startGameInput = raw_input('>>> >') if startGameInput == 'New_Game': startNewGame() break elif startGameInput == 'Load_Game': print "This function is not yet supported" print "Try Again" print else: print "You must have mistyped the command: Type either 'New_Game' or 'Load_Game'" print #Set the new game up: def startNewGame(): while 1: #Introduction: print print """Hello, You will now be guided through the setup process. There are 7 steps to this. You can cancel setup at any time by typing 'cancelSetup' Thankyou""" #Step 1 (Name): print print """Step 1 of 7: Type in a name for your PotatoHead: """ inputPHName = raw_input('|Enter Name:|') if inputPHName == 'cancelSetup': sys.exit() #Step 2 (Gender): print print """Step 2 of 7: Choose the gender of your PotatoHead: input either 'm' or 'f' """ inputPHGender = raw_input('|Enter Gender:|') if inputPHGender == 'cancelSetup': sys.exit() #Step 3 (Colour): print print """Step 3 of 7: Choose the colour your PotatoHead will be: Only Red, Blue, Green and Yellow are currently supported """ inputPHColour = raw_input('|Enter Colour:|') if inputPHColour == 'cancelSetup': sys.exit() #Step 4 (Favourite Thing): print print """Step 4 of 7: Type your PotatoHead's favourite thing: """ inputPHFavThing = raw_input('|Enter Favourite Thing:|') if inputPHFavThing == 'cancelSetup': sys.exit() # Step 5 (First Toy): print print """Step 5 of 7: Choose a first toy for your PotatoHead: """ inputPHFirstToy = raw_input('|Enter First Toy:|') if inputPHFirstToy == 'cancelSetup': sys.exit() #Step 6 (Check stats): while 1: print print """Step 6 of 7: Check the following details to make sure that they are correct: """ print print """Name:\t\t\t""" + inputPHName + """ Gender:\t\t\t""" + inputPHGender + """ Colour:\t\t\t""" + inputPHColour + """ Favourite Thing:\t""" + inputPHFavThing + """ First Toy:\t\t""" + inputPHFirstToy + """ """ print print "Enter 'y' or 'n'" inputMCheckStats = raw_input('|Is this information correct?|') if inputMCheckStats == 'cancelSetup': sys.exit() elif inputMCheckStats == 'y': break elif inputMCheckStats == 'n': print "Re-enter info: ..." print break else: "The value you entered was incorrect, please re-enter your choice" if inputMCheckStats == 'y': break #Step 7 (Define variables for the creation of the PotatoHead): MFCreatePH = [] print print """Step 7 of 7: Your PotatoHead will now be created... Creating variables... """ MFCreatePH = [inputPHName, inputPHGender, inputPHColour, inputPHFavThing, inputPHFirstToy] time.sleep(1) print "inputPHName" print time.sleep(1) print "inputPHFirstToy" print return MFCreatePH print "Your PotatoHead varibles have been successfully created!" #Run Program: welcomeMessage() MCreatePH = startGame() myPotatoHead = PotatoHead(MCreatePH) The potatohead.py module is as follows: #+--------------------------------------+# #| potatohead.py |# #| A module for the Potato Head Game |# #| Author: |# #| Date Created / Modified: |# #| 24/1/10 | 24/1/10 |# #+--------------------------------------+# Tested: Yes (24/1/10) #Create the PotatoHead class: class PotatoHead: #Initialise the PotatoHead object: def __init__(self, data): self.data = data #Takes the data from the start new game function - see main.py #Defines the PotatoHead starting attributes: self.name = data[0] self.gender = data[1] self.colour = data[2] self.favouriteThing = data[3] self.firstToy = data[4] self.age = '0.0' self.education = [self.eduScience, self.eduEnglish, self.eduMaths] = '0.0', '0.0', '0.0' self.fitness = '0.0' self.happiness = '10.0' self.health = '10.0' self.hunger = '0.0' self.tiredness = 'Not in this version' self.toys = [] self.toys.append(self.firstToy) self.time = '0' #Sets data lists for saving, loading and general use: self.phData = (self.name, self.gender, self.colour, self.favouriteThing, self.firstToy) self.phAdvData = (self.name, self.gender, self.colour, self.favouriteThing, self.firstToy, self.age, self.education, self.fitness, self.happiness, self.health, self.hunger, self.tiredness, self.toys) #Define the phStats variable, enabling easy display of PotatoHead attributes: def phDefStats(self): self.phStats = """Your Potato Head's Stats are as follows: ---------------------------------------- Name: \t\t""" + self.name + """ Gender: \t\t""" + self.gender + """ Colour: \t\t""" + self.colour + """ Favourite Thing: \t""" + self.favouriteThing + """ First Toy: \t""" + self.firstToy + """ Age: \t\t""" + self.age + """ Education: \t""" + str(float(self.eduScience) + float(self.eduEnglish) + float(self.eduMaths)) + """ -> Science: \t""" + self.eduScience + """ -> English: \t""" + self.eduEnglish + """ -> Maths: \t""" + self.eduMaths + """ Fitness: \t""" + self.fitness + """ Happiness: \t""" + self.happiness + """ Health: \t""" + self.health + """ Hunger: \t""" + self.hunger + """ Tiredness: \t""" + self.tiredness + """ Toys: \t\t""" + str(self.toys) + """ Time: \t\t""" + self.time + """ """ #Change the PotatoHead's favourite thing: def phChangeFavouriteThing(self, newFavouriteThing): self.favouriteThing = newFavouriteThing phChangeFavouriteThingMsg = "Your Potato Head's favourite thing is " + self.favouriteThing + "." #"Feed" the Potato Head i.e. Reduce the 'self.hunger' attribute's value: def phFeed(self): if float(self.hunger) >=3.0: self.hunger = str(float(self.hunger) - 3.0) elif float(self.hunger) < 3.0: self.hunger = '0.0' self.time = str(int(self.time) + 1) #Pass time #"Exercise" the Potato Head if between the ages of 5 and 25: def phExercise(self): if float(self.age) < 5.1 or float(self.age) > 25.1: print "This Potato Head is either too young or too old for this activity!" else: if float(self.fitness) <= 8.0: self.fitness = str(float(self.fitness) + 2.0) elif float(self.fitness) > 8.0: self.fitness = '10.0' self.time = str(int(self.time) + 1) #Pass time #"Teach" the Potato Head: def phTeach(self, subject): if subject == 'Science': if float(self.eduScience) <= 9.0: self.eduScience = str(float(self.eduScience) + 1.0) elif float(self.eduScience) > 9.0 and float(self.eduScience) < 10.0: self.eduScience = '10.0' elif float(self.eduScience) == 10.0: print "Your Potato Head has gained the highest level of qualifications in this subject! It cannot learn any more!" elif subject == 'English': if float(self.eduEnglish) <= 9.0: self.eduEnglish = str(float(self.eduEnglish) + 1.0) elif float(self.eduEnglish) > 9.0 and float(self.eduEnglish) < 10.0: self.eduEnglish = '10.0' elif float(self.eduEnglish) == 10.0: print "Your Potato Head has gained the highest level of qualifications in this subject! It cannot learn any more!" elif subject == 'Maths': if float(self.eduMaths) <= 9.0: self.eduMaths = str(float(self.eduMaths) + 1.0) elif float(self.eduMaths) > 9.0 and float(self.eduMaths) < 10.0: self.eduMaths = '10.0' elif float(self.eduMaths) == 10.0: print "Your Potato Head has gained the highest level of qualifications in this subject! It cannot learn any more!" else: print "That subject is not an option..." print "Please choose either Science, English or Maths" self.time = str(int(self.time) + 1) #Pass time #Increase Health: def phGoToDoctor(self): self.health = '10.0' self.time = str(int(self.time) + 1) #Pass time #Sleep: Age, change stats: #(Time Passes) def phSleep(self): self.time = '0' #Resets time for next 'day' (can do more things next day) #Increase hunger: if float(self.hunger) <= 5.0: self.hunger = str(float(self.hunger) + 5.0) elif float(self.hunger) > 5.0: self.hunger = '10.0' #Lower Fitness: if float(self.fitness) >= 0.5: self.fitness = str(float(self.fitness) - 0.5) elif float(self.fitness) < 0.5: self.fitness = '0.0' #Lower Health: if float(self.health) >= 0.5: self.health = str(float(self.health) - 0.5) elif float(self.health) < 0.5: self.health = '0.0' #Lower Happiness: if float(self.happiness) >= 2.0: self.happiness = str(float(self.happiness) - 2.0) elif float(self.happiness) < 2.0: self.happiness = '0.0' #Increase the Potato Head's age: self.age = str(float(self.age) + 0.1) The game is still under development - There may be parts of modules that aren't complete, but I don't think they're causing the problem

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testing Clojure in Maven

- by Ralph

I am new at Maven and even newer at Clojure. As an exercise to learn the language, I am writing a spider solitaire player program. I also plan on writing a similar program in Scala to compare the implementations (see my post http://stackoverflow.com/questions/2571267/modern-java-alternatives-closed). I have configured a Maven directory structure containing the usual src/main/clojure and src/test/clojure directories. My pom.xml file includes the clojure-maven-plugin. When I run "mvn test", it displays "No tests to run", despite my having test code in the src/test/clojure directory. As I misnaming something? Here is my pom.xml file: <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>SpiderPlayer</groupId> <artifactId>SpiderPlayer</artifactId> <version>1.0.0-SNAPSHOT</version> <inceptionYear>2010</inceptionYear> <packaging>jar</packaging> <properties> <maven.build.timestamp.format>yyMMdd.HHmm</maven.build.timestamp.format> <main.dir>org/dogdaze/spider_player</main.dir> <main.package>org.dogdaze.spider_player</main.package> <main.class>${main.package}.Main</main.class> </properties> <build> <sourceDirectory>src/main/clojure</sourceDirectory> <testSourceDirectory>src/main/clojure</testSourceDirectory> <plugins> <plugin> <groupId>com.theoryinpractise</groupId> <artifactId>clojure-maven-plugin</artifactId> <version>1.3.1</version> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-antrun-plugin</artifactId> <version>1.3</version> <executions> <execution> <goals> <goal>run</goal> </goals> <phase>generate-sources</phase> <configuration> <tasks> <echo file="${project.build.sourceDirectory}/${main.dir}/Version.clj" message="(ns ${main.package})${line.separator}"/> <echo file="${project.build.sourceDirectory}/${main.dir}/Version.clj" append="true" message="(def version "${maven.build.timestamp}")${line.separator}"/> </tasks> </configuration> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-assembly-plugin</artifactId> <version>2.1</version> <executions> <execution> <goals> <goal>single</goal> </goals> <phase>package</phase> <configuration> <descriptorRefs> <descriptorRef>jar-with-dependencies</descriptorRef> </descriptorRefs> <archive> <manifest> <mainClass>${main.class}</mainClass> </manifest> </archive> </configuration> </execution> </executions> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <configuration> <redirectTestOutputToFile>true</redirectTestOutputToFile> <skipTests>false</skipTests> <skip>false</skip> </configuration> <executions> <execution> <id>surefire-it</id> <phase>integration-test</phase> <goals> <goal>test</goal> </goals> <configuration> <skip>false</skip> </configuration> </execution> </executions> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>commons-cli</groupId> <artifactId>commons-cli</artifactId> <version>1.2</version> <scope>compile</scope> </dependency> </dependencies> </project> Here is my Clojure source file (src/main/clojure/org/dogdaze/spider_player/Deck.clj): ; Copyright 2010 Dogdaze (ns org.dogdaze.spider_player.Deck (:use [clojure.contrib.seq-utils :only (shuffle)])) (def suits [:clubs :diamonds :hearts :spades]) (def ranks [:ace :two :three :four :five :six :seven :eight :nine :ten :jack :queen :king]) (defn suit-seq "Return 4 suits: if number-of-suits == 1: :clubs :clubs :clubs :clubs if number-of-suits == 2: :clubs :diamonds :clubs :diamonds if number-of-suits == 4: :clubs :diamonds :hearts :spades." [number-of-suits] (take 4 (cycle (take number-of-suits suits)))) (defstruct card :rank :suit) (defn unshuffled-deck "Create an unshuffled deck containing all cards from the number of suits specified." [number-of-suits] (for [rank ranks suit (suit-seq number-of-suits)] (struct card rank suit))) (defn deck "Create a shuffled deck containing all cards from the number of suits specified." [number-of-suits] (shuffle (unshuffled-deck number-of-suits))) Here is my test case (src/test/clojure/org/dogdaze/spider_player/TestDeck.clj): ; Copyright 2010 Dogdaze (ns org.dogdaze.spider_player (:use clojure.set clojure.test org.dogdaze.spider_player.Deck)) (deftest test-suit-seq (is (= (suit-seq 1) [:clubs :clubs :clubs :clubs])) (is (= (suit-seq 2) [:clubs :diamonds :clubs :diamonds])) (is (= (suit-seq 4) [:clubs :diamonds :hearts :spades]))) (def one-suit-deck [{:rank :ace, :suit :clubs} {:rank :ace, :suit :clubs} {:rank :ace, :suit :clubs} {:rank :ace, :suit :clubs} {:rank :two, :suit :clubs} {:rank :two, :suit :clubs} {:rank :two, :suit :clubs} {:rank :two, :suit :clubs} {:rank :three, :suit :clubs} {:rank :three, :suit :clubs} {:rank :three, :suit :clubs} {:rank :three, :suit :clubs} {:rank :four, :suit :clubs} {:rank :four, :suit :clubs} {:rank :four, :suit :clubs} {:rank :four, :suit :clubs} {:rank :five, :suit :clubs} {:rank :five, :suit :clubs} {:rank :five, :suit :clubs} {:rank :five, :suit :clubs} {:rank :six, :suit :clubs} {:rank :six, :suit :clubs} {:rank :six, :suit :clubs} {:rank :six, :suit :clubs} {:rank :seven, :suit :clubs} {:rank :seven, :suit :clubs} {:rank :seven, :suit :clubs} {:rank :seven, :suit :clubs} {:rank :eight, :suit :clubs} {:rank :eight, :suit :clubs} {:rank :eight, :suit :clubs} {:rank :eight, :suit :clubs} {:rank :nine, :suit :clubs} {:rank :nine, :suit :clubs} {:rank :nine, :suit :clubs} {:rank :nine, :suit :clubs} {:rank :ten, :suit :clubs} {:rank :ten, :suit :clubs} {:rank :ten, :suit :clubs} {:rank :ten, :suit :clubs} {:rank :jack, :suit :clubs} {:rank :jack, :suit :clubs} {:rank :jack, :suit :clubs} {:rank :jack, :suit :clubs} {:rank :queen, :suit :clubs} {:rank :queen, :suit :clubs} {:rank :queen, :suit :clubs} {:rank :queen, :suit :clubs} {:rank :king, :suit :clubs} {:rank :king, :suit :clubs} {:rank :king, :suit :clubs} {:rank :king, :suit :clubs}]) (def two-suits-deck [{:rank :ace, :suit :clubs} {:rank :ace, :suit :diamonds} {:rank :ace, :suit :clubs} {:rank :ace, :suit :diamonds} {:rank :two, :suit :clubs} {:rank :two, :suit :diamonds} {:rank :two, :suit :clubs} {:rank :two, :suit :diamonds} {:rank :three, :suit :clubs} {:rank :three, :suit :diamonds} {:rank :three, :suit :clubs} {:rank :three, :suit :diamonds} {:rank :four, :suit :clubs} {:rank :four, :suit :diamonds} {:rank :four, :suit :clubs} {:rank :four, :suit :diamonds} {:rank :five, :suit :clubs} {:rank :five, :suit :diamonds} {:rank :five, :suit :clubs} {:rank :five, :suit :diamonds} {:rank :six, :suit :clubs} {:rank :six, :suit :diamonds} {:rank :six, :suit :clubs} {:rank :six, :suit :diamonds} {:rank :seven, :suit :clubs} {:rank :seven, :suit :diamonds} {:rank :seven, :suit :clubs} {:rank :seven, :suit :diamonds} {:rank :eight, :suit :clubs} {:rank :eight, :suit :diamonds} {:rank :eight, :suit :clubs} {:rank :eight, :suit :diamonds} {:rank :nine, :suit :clubs} {:rank :nine, :suit :diamonds} {:rank :nine, :suit :clubs} {:rank :nine, :suit :diamonds} {:rank :ten, :suit :clubs} {:rank :ten, :suit :diamonds} {:rank :ten, :suit :clubs} {:rank :ten, :suit :diamonds} {:rank :jack, :suit :clubs} {:rank :jack, :suit :diamonds} {:rank :jack, :suit :clubs} {:rank :jack, :suit :diamonds} {:rank :queen, :suit :clubs} {:rank :queen, :suit :diamonds} {:rank :queen, :suit :clubs} {:rank :queen, :suit :diamonds} {:rank :king, :suit :clubs} {:rank :king, :suit :diamonds} {:rank :king, :suit :clubs} {:rank :king, :suit :diamonds}]) (def four-suits-deck [{:rank :ace, :suit :clubs} {:rank :ace, :suit :diamonds} {:rank :ace, :suit :hearts} {:rank :ace, :suit :spades} {:rank :two, :suit :clubs} {:rank :two, :suit :diamonds} {:rank :two, :suit :hearts} {:rank :two, :suit :spades} {:rank :three, :suit :clubs} {:rank :three, :suit :diamonds} {:rank :three, :suit :hearts} {:rank :three, :suit :spades} {:rank :four, :suit :clubs} {:rank :four, :suit :diamonds} {:rank :four, :suit :hearts} {:rank :four, :suit :spades} {:rank :five, :suit :clubs} {:rank :five, :suit :diamonds} {:rank :five, :suit :hearts} {:rank :five, :suit :spades} {:rank :six, :suit :clubs} {:rank :six, :suit :diamonds} {:rank :six, :suit :hearts} {:rank :six, :suit :spades} {:rank :seven, :suit :clubs} {:rank :seven, :suit :diamonds} {:rank :seven, :suit :hearts} {:rank :seven, :suit :spades} {:rank :eight, :suit :clubs} {:rank :eight, :suit :diamonds} {:rank :eight, :suit :hearts} {:rank :eight, :suit :spades} {:rank :nine, :suit :clubs} {:rank :nine, :suit :diamonds} {:rank :nine, :suit :hearts} {:rank :nine, :suit :spades} {:rank :ten, :suit :clubs} {:rank :ten, :suit :diamonds} {:rank :ten, :suit :hearts} {:rank :ten, :suit :spades} {:rank :jack, :suit :clubs} {:rank :jack, :suit :diamonds} {:rank :jack, :suit :hearts} {:rank :jack, :suit :spades} {:rank :queen, :suit :clubs} {:rank :queen, :suit :diamonds} {:rank :queen, :suit :hearts} {:rank :queen, :suit :spades} {:rank :king, :suit :clubs} {:rank :king, :suit :diamonds} {:rank :king, :suit :hearts} {:rank :king, :suit :spades}]) (deftest test-unshuffled-deck (is (= (unshuffled-deck 1) one-suit-deck)) (is (= (unshuffled-deck 2) two-suits-deck)) (is (= (unshuffled-deck 4) four-suits-deck))) (deftest test-shuffled-deck (is (= (set (deck 1)) (set one-suit-deck))) (is (= (set (deck 2)) (set two-suits-deck))) (is (= (set (deck 4)) (set four-suits-deck)))) (run-tests) Any idea why the test is not running? BTW, feel free to suggest improvements to the Clojure code. Thanks, Ralph

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Error "Input length must be multiple of 8 when decrypting with padded cipher"

- by Ross Peoples

I am trying to move a project from C# to Java for a learning exercise. I am still very new to Java, but I have a TripleDES class in C# that encrypts strings and returns a string value of the encrypted byte array. Here is my C# code: using System; using System.IO; using System.Collections.Generic; using System.Security.Cryptography; using System.Text; namespace tDocc.Classes { /// <summary> /// Triple DES encryption class /// </summary> public static class TripleDES { private static byte[] key = { 110, 32, 73, 24, 125, 66, 75, 18, 79, 150, 211, 122, 213, 14, 156, 136, 171, 218, 119, 240, 81, 142, 23, 4 }; private static byte[] iv = { 25, 117, 68, 23, 99, 78, 231, 219 }; /// <summary> /// Encrypt a string to an encrypted byte array /// </summary> /// <param name="plainText">Text to encrypt</param> /// <returns>Encrypted byte array</returns> public static byte[] Encrypt(string plainText) { UTF8Encoding utf8encoder = new UTF8Encoding(); byte[] inputInBytes = utf8encoder.GetBytes(plainText); TripleDESCryptoServiceProvider tdesProvider = new TripleDESCryptoServiceProvider(); ICryptoTransform cryptoTransform = tdesProvider.CreateEncryptor(key, iv); MemoryStream encryptedStream = new MemoryStream(); CryptoStream cryptStream = new CryptoStream(encryptedStream, cryptoTransform, CryptoStreamMode.Write); cryptStream.Write(inputInBytes, 0, inputInBytes.Length); cryptStream.FlushFinalBlock(); encryptedStream.Position = 0; byte[] result = new byte[encryptedStream.Length]; encryptedStream.Read(result, 0, (int)encryptedStream.Length); cryptStream.Close(); return result; } /// <summary> /// Decrypt a byte array to a string /// </summary> /// <param name="inputInBytes">Encrypted byte array</param> /// <returns>Decrypted string</returns> public static string Decrypt(byte[] inputInBytes) { UTF8Encoding utf8encoder = new UTF8Encoding(); TripleDESCryptoServiceProvider tdesProvider = new TripleDESCryptoServiceProvider(); ICryptoTransform cryptoTransform = tdesProvider.CreateDecryptor(key, iv); MemoryStream decryptedStream = new MemoryStream(); CryptoStream cryptStream = new CryptoStream(decryptedStream, cryptoTransform, CryptoStreamMode.Write); cryptStream.Write(inputInBytes, 0, inputInBytes.Length); cryptStream.FlushFinalBlock(); decryptedStream.Position = 0; byte[] result = new byte[decryptedStream.Length]; decryptedStream.Read(result, 0, (int)decryptedStream.Length); cryptStream.Close(); UTF8Encoding myutf = new UTF8Encoding(); return myutf.GetString(result); } /// <summary> /// Decrypt an encrypted string /// </summary> /// <param name="text">Encrypted text</param> /// <returns>Decrypted string</returns> public static string DecryptText(string text) { if (text == "") { return text; } return Decrypt(Convert.FromBase64String(text)); } /// <summary> /// Encrypt a string /// </summary> /// <param name="text">Unencrypted text</param> /// <returns>Encrypted string</returns> public static string EncryptText(string text) { if (text == "") { return text; } return Convert.ToBase64String(Encrypt(text)); } } /// <summary> /// Random number generator /// </summary> public static class RandomGenerator { /// <summary> /// Generate random number /// </summary> /// <param name="length">Number of randomizations</param> /// <returns>Random number</returns> public static int GenerateNumber(int length) { byte[] randomSeq = new byte[length]; new RNGCryptoServiceProvider().GetBytes(randomSeq); int code = Environment.TickCount; foreach (byte b in randomSeq) { code += (int)b; } return code; } } /// <summary> /// Hash generator class /// </summary> public static class Hasher { /// <summary> /// Hash type /// </summary> public enum eHashType { /// <summary> /// MD5 hash. Quick but collisions are more likely. This should not be used for anything important /// </summary> MD5 = 0, /// <summary> /// SHA1 hash. Quick and secure. This is a popular method for hashing passwords /// </summary> SHA1 = 1, /// <summary> /// SHA256 hash. Slower than SHA1, but more secure. Used for encryption keys /// </summary> SHA256 = 2, /// <summary> /// SHA348 hash. Even slower than SHA256, but offers more security /// </summary> SHA348 = 3, /// <summary> /// SHA512 hash. Slowest but most secure. Probably overkill for most applications /// </summary> SHA512 = 4, /// <summary> /// Derrived from MD5, but only returns 12 digits /// </summary> Digit12 = 5 } /// <summary> /// Hashes text using a specific hashing method /// </summary> /// <param name="text">Input text</param> /// <param name="hash">Hash method</param> /// <returns>Hashed text</returns> public static string GetHash(string text, eHashType hash) { if (text == "") { return text; } if (hash == eHashType.MD5) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA1) { SHA1Managed hasher = new SHA1Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA256) { SHA256Managed hasher = new SHA256Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA348) { SHA384Managed hasher = new SHA384Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.SHA512) { SHA512Managed hasher = new SHA512Managed(); return ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); } else if (hash == eHashType.Digit12) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); string newHash = ByteToHex(hasher.ComputeHash(Encoding.ASCII.GetBytes(text))); return newHash.Substring(0, 12); } return ""; } /// <summary> /// Generates a hash based on a file's contents. Used for detecting changes to a file and testing for duplicate files /// </summary> /// <param name="info">FileInfo object for the file to be hashed</param> /// <param name="hash">Hash method</param> /// <returns>Hash string representing the contents of the file</returns> public static string GetHash(FileInfo info, eHashType hash) { FileStream hashStream = new FileStream(info.FullName, FileMode.Open, FileAccess.Read); string hashString = ""; if (hash == eHashType.MD5) { MD5CryptoServiceProvider hasher = new MD5CryptoServiceProvider(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA1) { SHA1Managed hasher = new SHA1Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA256) { SHA256Managed hasher = new SHA256Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA348) { SHA384Managed hasher = new SHA384Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } else if (hash == eHashType.SHA512) { SHA512Managed hasher = new SHA512Managed(); hashString = ByteToHex(hasher.ComputeHash(hashStream)); } hashStream.Close(); hashStream.Dispose(); hashStream = null; return hashString; } /// <summary> /// Converts a byte array to a hex string /// </summary> /// <param name="data">Byte array</param> /// <returns>Hex string</returns> public static string ByteToHex(byte[] data) { StringBuilder builder = new StringBuilder(); foreach (byte hashByte in data) { builder.Append(string.Format("{0:X1}", hashByte)); } return builder.ToString(); } /// <summary> /// Converts a hex string to a byte array /// </summary> /// <param name="hexString">Hex string</param> /// <returns>Byte array</returns> public static byte[] HexToByte(string hexString) { byte[] returnBytes = new byte[hexString.Length / 2]; for (int i = 0; i <= returnBytes.Length - 1; i++) { returnBytes[i] = byte.Parse(hexString.Substring(i * 2, 2), System.Globalization.NumberStyles.HexNumber); } return returnBytes; } } } And her is what I've got for Java code so far, but I'm getting the error "Input length must be multiple of 8 when decrypting with padded cipher" when I run the test on this: import java.security.InvalidAlgorithmParameterException; import java.security.InvalidKeyException; import javax.crypto.Cipher; import javax.crypto.NoSuchPaddingException; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import com.tdocc.utils.Base64; public class TripleDES { private static byte[] keyBytes = { 110, 32, 73, 24, 125, 66, 75, 18, 79, (byte)150, (byte)211, 122, (byte)213, 14, (byte)156, (byte)136, (byte)171, (byte)218, 119, (byte)240, 81, (byte)142, 23, 4 }; private static byte[] ivBytes = { 25, 117, 68, 23, 99, 78, (byte)231, (byte)219 }; public static String encryptText(String plainText) { try { if (plainText.isEmpty()) return plainText; return Base64.decode(TripleDES.encrypt(plainText)).toString(); } catch (Exception e) { e.printStackTrace(); } return null; } public static byte[] encrypt(String plainText) throws InvalidKeyException, InvalidAlgorithmParameterException, NoSuchPaddingException { try { final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(ivBytes); final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, key, iv); final byte[] plainTextBytes = plainText.getBytes("utf-8"); final byte[] cipherText = cipher.doFinal(plainTextBytes); return cipherText; } catch (Exception e) { e.printStackTrace(); } return null; } public static String decryptText(String message) { try { if (message.isEmpty()) return message; else return TripleDES.decrypt(message.getBytes()); } catch (Exception e) { e.printStackTrace(); } return null; } public static String decrypt(byte[] message) { try { final SecretKey key = new SecretKeySpec(keyBytes, "DESede"); final IvParameterSpec iv = new IvParameterSpec(ivBytes); final Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, key, iv); final byte[] plainText = cipher.doFinal(message); return plainText.toString(); } catch (Exception e) { e.printStackTrace(); } return null; } }

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