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• Enterprise Service Bus (ESB): Important architectural piece to a SOA or is it just vendor hype?

  Is an Enterprise Service Bus (ESB) an important architectural piece to a Service-Oriented Architecture (SOA), or is it just vendor hype in order to sell a particular product such as SOA-in-a-box? According to IBM.com, an ESB is a flexible connectivity infrastructure for integrating applications and services; it offers a flexible and manageable approach to service-oriented architecture implementation. With this being said, it is my personal belief that ESBs are an important architectural piece to any SOA. Additionally, generic design patterns have been created around the integration of web services in to ESB regardless of any vendor. ESB design patterns, according to Philip Hartman, can be classified in to the following categories: Interaction Patterns: Enable service interaction points to send and/or receive messages from the bus Mediation Patterns: Enable the altering of message exchanges Deployment Patterns: Support solution deployment into a federated infrastructure Examples of Interaction Patterns: One-Way Message Synchronous Interaction Asynchronous Interaction Asynchronous Interaction with Timeout Asynchronous Interaction with a Notification Timer One Request, Multiple Responses One Request, One of Two Possible Responses One Request, a Mandatory Response, and an Optional Response Partial Processing Multiple Application Interactions Benefits of the Mediation Pattern: Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently Design an intermediary to decouple many peers Promote the many-to-many relationships between interacting peers to “full object status” Examples of Interaction Patterns: Global ESB: Services share a single namespace and all service providers are visible to every service requester across an entire network Directly Connected ESB: Global service registry that enables independent ESB installations to be visible Brokered ESB: Bridges services that are reluctant to expose requesters or providers to ESBs in other domains Federated ESB: Service consumers and providers connect to the master or to a dependent ESB to access services throughout the network References: Mediator Design Pattern. (2011). Retrieved 2011, from SourceMaking.com: http://sourcemaking.com/design_patterns/mediator Hartman, P. (2006, 24 1). ESB Patterns that "Click". Retrieved 2011, from The Art and Science of Being an IT Architect: http://artsciita.blogspot.com/2006/01/esb-patterns-that-click.html IBM. (2011). WebSphere DataPower XC10 Appliance Version 2.0. Retrieved 2011, from IBM.com: http://publib.boulder.ibm.com/infocenter/wdpxc/v2r0/index.jsp?topic=%2Fcom.ibm.websphere.help.glossary.doc%2Ftopics%2Fglossary.html Oracle. (2005). 12 Interaction Patterns. Retrieved 2011, from Oracle® BPEL Process Manager Developer's Guide: http://docs.oracle.com/cd/B31017_01/integrate.1013/b28981/interact.htm#BABHHEHD

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• Memory read/write access efficiency

  - by wolfPack88

  I've heard conflicting information from different sources, and I'm not really sure which one to believe. As such, I'll post what I understand and ask for corrections. Let's say I want to use a 2D matrix. There are three ways that I can do this (at least that I know of). 1: int i; char **matrix; matrix = malloc(50 * sizeof(char *)); for(i = 0; i < 50; i++) matrix[i] = malloc(50); 2: int i; int rowSize = 50; int pointerSize = 50 * sizeof(char *); int dataSize = 50 * 50; char **matrix; matrix = malloc(dataSize + pointerSize); char *pData = matrix + pointerSize - rowSize; for(i = 0; i < 50; i++) { pData += rowSize; matrix[i] = pData; } 3: //instead of accessing matrix[i][j] here, we would access matrix[i * 50 + j] char *matrix = malloc(50 * 50); In terms of memory usage, my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient, for the reasons below: 3: There is only one pointer and one allocation, and therefore, minimal overhead. 2: Once again, there is only one allocation, but there are now 51 pointers. This means there is 50 * sizeof(char *) more overhead. 1: There are 51 allocations and 51 pointers, causing the most overhead of all options. In terms of performance, once again my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient. Reasons being: 3: Only one memory access is needed. We will have to do a multiplication and an addition as opposed to two additions (as in the case of a pointer to a pointer), but memory access is slow enough that this doesn't matter. 2: We need two memory accesses; once to get a char *, and then to the appropriate char. Only two additions are performed here (once to get to the correct char * pointer from the original memory location, and once to get to the correct char variable from wherever the char * points to), so multiplication (which is slower than addition) is not required. However, on modern CPUs, multiplication is faster than memory access, so this point is moot. 1: Same issues as 2, but now the memory isn't contiguous. This causes cache misses and extra page table lookups, making it the least efficient of the lot. First and foremost: Is this correct? Second: Is there an option 4 that I am missing that would be even more efficient?

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• Cloud Computing: Start with the problem

  - by BuckWoody

  At one point in my life I would build my own computing system for home use. I wanted a particular video card, a certain set of drives, and a lot of memory. Not only could I not find those things in a vendor’s pre-built computer, but those were more expensive – by a lot. As time moved on and the computing industry matured, I actually find that I can buy a vendor’s system as cheaply – and in some cases far more cheaply – than I can build it myself.   This paradigm holds true for almost any product, even clothing and furniture. And it’s also held true for software… Mostly. If you need an office productivity package, you simply buy one or use open-sourced software for that. There’s really no need to write your own Word Processor – it’s kind of been done a thousand times over. Even if you need a full system for customer relationship management or other needs, you simply buy one. But there is no “cloud solution in a box”.  Sure, if you’re after “Software as a Service” – type solutions, like being able to process video (Windows Azure Media Services) or running a Pig or Hive job in Hadoop (Hadoop on Windows Azure) you can simply use one of those, or if you just want to deploy a Virtual Machine (Windows Azure Virtual Machines) you can get that, but if you’re looking for a solution to a problem your organization has, you may need to mix Software, Infrastructure, and perhaps even Platforms (such as Windows Azure Computing) to solve the issue. It’s all about starting from the problem-end first. We’ve become so accustomed to looking for a box of software that will solve the problem, that we often start with the solution and try to fit it to the problem, rather than the other way around.  When I talk with my fellow architects at other companies, one of the hardest things to get them to do is to ignore the technology for a moment and describe what the issues are. It’s interesting to monitor the conversation and watch how many times we deviate from the problem into the solution. So, in your work today, try a little experiment: watch how many times you go after a problem by starting with the solution. Tomorrow, make a conscious effort to reverse that. You might be surprised at the results.

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• How to discriminate from two nodes with identical frequencies in a Huffman's tree?

  - by Omega

  Still on my quest to compress/decompress files with a Java implementation of Huffman's coding (http://en.wikipedia.org/wiki/Huffman_coding) for a school assignment. From the Wikipedia page, I quote: Create a leaf node for each symbol and add it to the priority queue. While there is more than one node in the queue: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. Add the new node to the queue. The remaining node is the root node and the tree is complete. Now, emphasis: Remove the two nodes of highest priority (lowest probability) from the queue Create a new internal node with these two nodes as children and with probability equal to the sum of the two nodes' probabilities. So I have to take two nodes with the lowest frequency. What if there are multiple nodes with the same low frequency? How do I discriminate which one to use? The reason I ask this is because Wikipedia has this image: And I wanted to see if my Huffman's tree was the same. I created a file with the following content: aaaaeeee nnttmmiihhssfffouxprl And this was the result: Doesn't look so bad. But there clearly are some differences when multiple nodes have the same frequency. My questions are the following: What is Wikipedia's image doing to discriminate the nodes with the same frequency? Is my tree wrong? (Is Wikipedia's image method the one and only answer?) I guess there is one specific and strict way to do this, because for our school assignment, files that have been compressed by my program should be able to be decompressed by other classmate's programs - so there must be a "standard" or "unique" way to do it. But I'm a bit lost with that. My code is rather straightforward. It literally just follows Wikipedia's listed steps. The way my code extracts the two nodes with the lowest frequency from the queue is to iterate all nodes and if the current node has a lower frequency than any of the two "smallest" known nodes so far, then it replaces the highest one. Just like that.

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• Blender to 3ds max to cal3d format

  - by Kaliber64

  There are quite a few questions on cal3d but they are old and don't apply anymore. In Blender(must be 2.49a for python script to work!!!): I have a scene with 7 meshes, 1 armature, 10 bones. I tried going to one mesh to simplify it but doesn't change anything. I found a small blend file that was used for cal3d and it exported just fine. So I tried to copy it's setup with no success. EDIT*8/13/2012 In the last week here is what I have found so far. I made the mesh in the newest blender(2.62?) and exported it to import it in the old one(2.49a). Did an animation in the old one because importing new blend files to old blenders, its just said it would lose keyframe data and all was good. And then you get the last problem of it not exporting meshes. BUT I found that meshes made in the old one export regardless. I can't find any that won't export. So if I used the old blender to remake my model I could get it to export :) At this point I found a modified release of cal3d (because the most core model variable would not initiate as I made a really small test subject in old blender instead of remaking my big one which took 4 hours.) which fixes the morph objects and adds what cal3d left off with. Under their license they have to release the modification but it has no documentation so I have to figure it out on my own. Its mostly the same. But with this lib it came with a 3ds max exporter. My question now is how do I transfer armature and mesh information from blender to 3ds max in order to export into cal3d format. Every time I try the models are see through and small and there are no bones. The formats I have tried to import are .3ds .obj(mesh only) and COLLADA. In all of them the mesh is invisible and no bones. It says the default texture is on so I should be able to see it. All the vertices are present I found a vertex highlighter so I can see those. If any of this is confusing let me know so I can clear it up. Its late .<=sleep.

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• Several New Hints

  - by Ondrej Brejla

  Hi all! Today we would like to introduce you some of our new experimental hints for NetBeans 7.2. They are called: Unused Use Statement and Immutable Variables. Unused Use Statement This hint is quite simple. It highlights (underlines) your use statements, which are not used. Typical use case is after some refactoring, when you forgot to remove some obsolete use statements. This hint warns you on them and allows you to remove them easily. Just click on the hint bulb in the gutter and select Remove Unused Use Statement. And of course, it works in multiple use statements combined too. Immutable Variables The next one is the hint which checks too many assignments into a variable. And why? That's simple. Mostly you should use just one assignment into one variable. But sometimes you are lazy and you do something like: But it's quite wrong, because what you really do is: And that's exactly the case, when our new hint warns you, that Too many assignments (2) into variable $foo occured. Nothing more. Yes, we know that there are some cases, where could be more assignments and no warning should occur, e.g.: Because maybe one likes longer increment syntax more than the short one. So we tried to handle these cases to don't bother you if it's not a need. Note: We are almost sure that this hint doesn't cover all your use cases, because there are a lot of them. So if you find something strange, write it into our bugzilla so we can handle it better for you. Thanks for your patience! And the last thing is, that you can set the number of allowed assignments in Tools -> Options -> Editor -> Hints -> PHP: Immutable Variables. Note: This hint works just for a common variables, not for fields. We have an enhancement request for that and it should be implemented in next version of NetBeans (probably 7.3). And that's all for today and as usual, please test it and if you find something strange, don't hesitate to file a new issue (product php, component Editor). Thanks.

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• Indefinite loops where the first time is different

  - by George T

  This isn't a serious problem or anything someone has asked me to do, just a seemingly simple thing that I came up with as a mental exercise but has stumped me and which I feel that I should know the answer to already. There may be a duplicate but I didn't manage to find one. Suppose that someone asked you to write a piece of code that asks the user to enter a number and, every time the number they entered is not zero, says "Error" and asks again. When they enter zero it stops. In other words, the code keeps asking for a number and repeats until zero is entered. In each iteration except the first one it also prints "Error". The simplest way I can think of to do that would be something like the folloing pseudocode: int number = 0; do { if(number != 0) { print("Error"); } print("Enter number"); number = getInput(); }while(number != 0); While that does what it's supposed to, I personally don't like that there's repeating code (you test number != 0 twice) -something that should generally be avoided. One way to avoid this would be something like this: int number = 0; while(true) { print("Enter number"); number = getInput(); if(number == 0) { break; } else { print("Error"); } } But what I don't like in this one is "while(true)", another thing to avoid. The only other way I can think of includes one more thing to avoid: labels and gotos: int number = 0; goto question; error: print("Error"); question: print("Enter number"); number = getInput(); if(number != 0) { goto error; } Another solution would be to have an extra variable to test whether you should say "Error" or not but this is wasted memory. Is there a way to do this without doing something that's generally thought of as a bad practice (repeating code, a theoretically endless loop or the use of goto)? I understand that something like this would never be complex enough that the first way would be a problem (you'd generally call a function to validate input) but I'm curious to know if there's a way I haven't thought of.

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• Cone of Uncertainty in classic and agile projects

  - by DigiMortal

  David Starr from Scrum.org made interesting session in TechEd Europe 2012 - Implementing Scrum Using Team Foundation Server 2012. One of interesting things for me was how Cone of Uncertainty looks like in agile projects (or how agile methodologies distort the cone we know from waterfall projects). This posting illustrates two cones – one for waterfall and one for agile world. Cone of Uncertainty Cone of Uncertainty was introduced to software development community by Steve McConnell and it visualizes how accurate are our estimates over project timeline. Here is the Cone of Uncertainty when we deal with waterfall and Big Design Up-Front (BDUF). Cone of Uncertainty. Taken from MSDN Library page Estimating. The closer we are to project end the more accurate are our estimates. When project ends we know exactly how much every task took time. As we can see then cone is wide when we usually have to give our estimates – it happens somewhere between Initial Project Concept and Requirements Complete. Don’t ask me why Initial Project Concept is the stage where some companies give their best estimates – they just do it every time and doesn’t learn a thing later. This cone is inevitable for software development and agile methodologies that try to make software world better are also able to change the cone. Cone of Uncertainty in agile projects Agile methodologies usually try to avoid BDUF, waterfalls and other things that make all our mistakes highly expensive. Of course, we are not the only ones who make mistakes – don’t also forget our dear customers. Agile methodologies take development as creational work and focus on making it better. One main trick is to focus on small and short iterations. What it means? We are estimating functionalities that are easier for us to understand and implement. Therefore our estimates are more accurate. As we move from few big iterations to many small iterations we also distort and slice Cone of Uncertainty. This is how cone looks when agile methodologies are used. Cone of Uncertainty in agile projects. We have more cones to live with but they are way smaller. I don’t have any numbers to put here because I found any but still this “chart” should give you the point: more smaller iterations cause more but way smaller cones of uncertainty. We can handle these small uncertainties because steps we take to complete small tasks are more predictable and doesn’t grow very often above our heads. One more note. Consider that both of charts given in this posting describe exactly the same phase of same project – just uncertainties are different.

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• Finding "Stuff" In OUM

  - by Dave Burke

  One of the first questions people asked when they start using the Oracle Unified Method (OUM) is “how do I find X ?” Well of course no one is really looking for “X”!! but typically an OUM user might know the Task ID, or part of the Task Name, or maybe they just want to find out if there is any content within OUM that is related to a couple of keys words they have in their mind. Here are three quick tips I give people: 1. Open up one of the OUM Views, then click “Expand All”, and then use your Browser’s search function to locate a key Word. For example, Google Chrome or Internet Explorer: <CTRL> F, then type in a key Word, i.e. Architecture This is fast and easy option to use, but it only searches the current OUM page 2. Use the PDF view of OUM Open up one of the OUM Views, and then click the PDF View button located at the top of the View. Depending on your Browser’s settings, the PDF file will either open up in a new Window, or be saved to your local machine. In either case, once the PDF file is open, you can use the built in PDF search commands to search for key words across a large portion of the OUM Method Pack. This is great option for searching the entire Full Method View of OUM, including linked HTML pages, however the search will not included linked Documents, i.e. Word, Excel. 3. Use your operating systems file index to search for key words This is my favorite option, and one I use virtually every day. I happen to use Windows Search, but you could also use Google Desktop Search, of Finder on a MAC. All you need to do (on a Windows machine) is to make sure your local OUM folder structure is included in the Windows Index. Go to Control Panel, select Indexing Options, and ensure your OUM folder is included in the Index, i.e. C:/METHOD/OM40/OUM_5.6 Once your OUM folders are indexed, just open up Windows Search (or Google Desktop Search) and type in your key worlds, i.e. Unit Testing The reason I use this option the most is because the Search will take place across the entire content of the Indexed folders, included linked files. Happy searching!

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• Is it unusual for a small company (15 developers) not to use managed source/version control?

  - by LordScree

  It's not really a technical question, but there are several other questions here about source control and best practice. The company I work for (which will remain anonymous) uses a network share to host its source code and released code. It's the responsibility of the developer or manager to manually move source code to the correct folder depending on whether it's been released and what version it is and stuff. We have various spreadsheets dotted around where we record file names and versions and what's changed, and some teams also put details of different versions at the top of each file. Each team (2-3 teams) seems to do this differently within the company. As you can imagine, it's an organised mess - organised, because the "right people" know where their stuff is, but a mess because it's all different and it relies on people remembering what to do at any one time. One good thing is that everything is backed up on a nightly basis and kept indefinitely, so if mistakes are made, snapshots can be recovered. I've been trying to push for some kind of managed source control for a while, but I can't seem to get enough support for it within the company. My main arguments are: We're currently vulnerable; at any point someone could forget to do one of the many release actions we have to do, which could mean whole versions are not stored correctly. It could take hours or even days to piece a version back together if necessary We're developing new features along with bug fixes, and often have to delay the release of one or the other because some work has not been completed yet. We also have to force customers to take versions that include new features even if they just want a bug fix, because there's only really one version we're all working on We're experiencing problems with Visual Studio because multiple developers are using the same projects at the same time (not the same files, but it's still causing problems) There are only 15 developers, but we all do stuff differently; wouldn't it be better to have a standard company-wide approach we all have to follow? My questions are: Is it normal for a group of this size not to have source control? I have so far been given only vague reasons for not having source control - what reasons would you suggest could be valid for not implementing source control, given the information above? Are there any more reasons for source control that I could add to my arsenal? I'm asking mainly to get a feel for why I have had so much resistance, so please answer honestly. I'll give the answer to the person I believe has taken the most balanced approach and has answered all three questions. Thanks in advance

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• MVC - Cocoa interface - Cocoa Design pattern book

  - by Idan

  So I started reading this book: http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022 On chapter 2 it explains about the MVC design pattern and gives and example which I need some clarification to. The simple example shows a view with the following fields: hourlyRate, WorkHours, Standarthours , salary. The example is devided into 3 parts : View - contains some text fiels and a table (the table contains a list of employees' data). Controller - comprised of NSArrayController class (contains an array of MyEmployee) Model - MyEmployee class which describes an employee. MyEmployee class has one method which return the salary according to the calculation logic, and attributes in accordance with the view UI controls. MyEmployee inherits from NSManagedObject. Few things i'm not sure of : 1. Inside the MyEmplpyee class implemenation file, the calculation method gets the class attributes using sentence like " [[self valueForKey:@"hourlyRate"] floatValue];" Howevern, inside the header there is no data member named hourlyRate or any of the view fields. I'm not quite sure how does it work, and how it gets the value from the right view field. (does it have to be the same name as the field name in the view). maybe the conncetion is made somehow using the Interface builder and was not shown in the book ? and more important: 2. how does it seperate the view from the model ? let's say ,as the book implies might happen, I decide one day to remove one of the fields in the view. as far as I understand, that means changing the way the salary method works in MyEmplpyee (cause we have one field less) , and removing one attribute from the same calss. So how is that separate the View from the Model if changing one reflect on the other ? I guess I get something wrong... Any comments ? Thanks

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• Asp.net MVC Route class that supports catch-all parameter anywhere in the URL

  - by Robert Koritnik

  the more I think about it the more I believe it's possible to write a custom route that would consume these URL definitions: {var1}/{var2}/{var3} Const/{var1}/{var2} Const1/{var1}/Const2/{var2} {var1}/{var2}/Const as well as having at most one greedy parameter on any position within any of the upper URLs like {*var1}/{var2}/{var3} {var1}/{*var2}/{var3} {var1}/{var2}/{*var3} There is one important constraint. Routes with greedy segment can't have any optional parts. All of them are mandatory. Example This is an exemplary request http://localhost/Show/Topic/SubTopic/SubSubTopic/123/This-is-an-example This is URL route definition {action}/{*topicTree}/{id}/{title} Algorithm Parsing request route inside GetRouteData() should work like this: Split request into segments: Show Topic SubTopic SubSubTopic 123 This-is-an-example Process route URL definition starting from the left and assigning single segment values to parameters (or matching request segment values to static route constant segments). When route segment is defined as greedy, reverse parsing and go to the last segment. Parse route segments one by one backwards (assigning them request values) until you get to the greedy catch-all one again. When you reach the greedy one again, join all remaining request segments (in original order) and assign them to the greedy catch-all route parameter. Questions As far as I can think of this, it could work. But I would like to know: Has anyone already written this so I don't have to (because there are other aspects to parsing as well that I didn't mention (constraints, defaults etc.) Do you see any flaws in this algorithm, because I'm going to have to write it myself if noone has done it so far. I haven't thought about GetVirtuaPath() method at all.

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• Creating a Sharepoint Development Environment from an Existing Production Environment

  - by Starky

  I have very little experience using Sharepoint but a good amount using Visual Studio 2008, SQL Server 2005, Windows Server 2003 and IIS6. I need to create a development environment for a SharePoint 2007 system that will be used internally. The system is already deployed over two servers - one of the servers simply holds the database and everything else is on the other server. We are also using WSS 3.0. I have created a Virtual Machine with all the required software including a clean installation of SharePoint Server 2007 and I wish to use this single Virtual Machine as the development environment. Right now there are no custom assemblies being used on the production server as far as I am aware. There are 3 websites, one over port 80 for user accesss, one over a custom port for central administration, and one over another custom port. Not sure what the last one is for but my blank instance of Sharepoint on my Virtual Machine also has something similar. I attempted to use the STSADM tool to backup and restore these 3 sites from my production environment to my development environment and while the operations completed succesfully, the central administration site in my development environment acted strangely and I could not access port 80 - I did not seem to have correct credentials for it. I suspected that it would not have been so simple so could I please have advice on how to create my development environment so that I can use it to deploy updates to the production one.

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• LINQ to SQL: filter nested objects with soft deletes

  - by Alex

  Hello everyone, I'm using soft deleting in my database (IsDeleted field). I'm actively using LoadWith and AssociateWith methods to retrieve and filter nested records. The thing is AssociateWith only works with properties that represents a one-to-many relationship. DataLoadOptions loadOptions = new DataLoadOptions(); loadOption.LoadWith<User>(u = > u.Roles); loadOption.AssociateWith<User>(u = > u.Roles.Where(r = > !r.IsDeleted)); In the example above I just say: I want to retrieve users with related (undeleted) roles. But when I have one-to-one relationship, e.g. Document - File (the only one file is related to the document) I'm unable to filter soft deleted object: DataLoadOptions loadOptions = new DataLoadOptions(); loadOption.LoadWith<Document>(d = > d.File); // the next certainly won't work loadOption.AssociateWith<File>(f = > !f.IsDeleted); So, is there any idea how to filter records within the one-to-one relationship? Thanks!

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• NHibernate - joining on a subquery using ICriteria

  - by owensymes.mp

  I have a SQL query that I need to represent using NHibernate's ICriteria API. SELECT u.Id as Id, u.Login as Login, u.FirstName as FirstName, u.LastName as LastName, gm.UserGroupId_FK as UserGroupId, inner.Data1, inner.Data2, inner.Data3 FROM dbo.User u inner join dbo.GroupMember gm on u.Id = gm.UserAnchorId_FK left join ( SELECT di.UserAnchorId_FK, sum(di.Data1) as Data1, sum(di.Data2) as Data2, sum(di.Data3) as Data3 FROM dbo.DailyInfo di WHERE di.Date between '2009-04-01' and '2009-06-01' GROUP BY di.UserAnchorId_FK ) inner ON inner.UserAnchorId_FK = u.Id WHERE gm.UserGroupId_FK = 195 Attempts so far have included mapping 'User' and 'DailyInfo' classes (my entities) and making a DailyInfo object a property of the User object. However, how to map the foreign key relationship between them is still a mystery, ie <one-to-one></one-to-one> <one-to-many></one-to-many> <generator class="foreign"><param name="property">Id</param></generator> (!) Solutions on the web are generally to do with subqueries within a WHERE clause, however I need to left join on this subquery instead to ensure NULL values are returned for rows that do not join. I have the feeling that I should be using a Criteria for the outer query, then forming a 'join' with a DetachedCriteria to represent the subquery?

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• JAVA Regular Expression Errors

  - by Berkay

  I'm working on a simply password strength checker and i can not success applying regular expressions. In different resources different kinds of regular expressions are defined. i also find javascript regular expressions but had some problems to adapt. First, these are the regular expressions i need for JAVA: at least one lower case letter at least one upper case letter at least one number at least three numbers at least one special character at least two special characters both letters and numbers both upper and lower case letters, numbers, and special characters My goal is not being a regular expression expert i just want to use the parts i need.If you direct me good tutorials which discusses above for java, will be appreciated. Second, in this link some of them are mentioned but i'm getting problems to apply them. here does not catch the lower case letter (my pass: A5677a) if (passwd.matches("(?=.*[a-z])")) // [verified] at least one lower case letter {Score = Score+5;} Also here i'm getting error : illegal escape character. if (passwd.matches("(?=.*\d)")) // [verified] at least one number Finally, are these expressions all different in different kind of programming or script languages?

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• Static method , Abstract method , Interface method comparision ?

  - by programmerist

  When i choose these methods? i can not decide which one i must prefer or when will i use one of them?which one give best performance? First Type Usage public abstract class _AccessorForSQL { public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType); public virtual bool Update(); public virtual bool Delete(); public virtual DataSet Select(); } class GenAccessor : _AccessorForSQL { DataSet ds; DataTable dt; public override bool Save(string sp, ListDictionary ld, CommandType cmdType) { } public override bool Update() { return true; } public override bool Delete() { return true; } public override DataSet Select() { DataSet dst = new DataSet(); return dst; } Second Type Usage Also i can write it below codes: public class GenAccessor { public Static bool Save() { } public Static bool Update() { } public Static bool Delete() { } } Third Type Usage Also i can write it below codes: public interface IAccessorForSQL { bool Delete(); bool Save(string sp, ListDictionary ld, CommandType cmdType); DataSet Select(); bool Update(); } public class _AccessorForSQL : IAccessorForSQL { private DataSet ds; private DataTable dt; public virtual bool Save(string sp, ListDictionary ld, CommandType cmdType) { } } } I can use first one below usage: GenAccessor gen = New GenAccessor(); gen.Save(); I can use second one below usage: GenAccessor.Save(); Which one do you prefer? When will i use them? which time i need override method ? which time i need static method?

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• ACL architechture for a Software As a service in Spring 3.0

  - by geoaxis

  I am making a software as a service using Spring 3.0 (Spring MVC, Spring Security, Spring Roo, Hibernate) I have to come up with a flexible access control list mechanism.I have three different kinds of users System (who can do any thing to the system, includes admin and internal daemons) Operations (who can add and delete users, organizations, and do maintenance work on behalf of users and organizations) End Users (they belong to one or more organization, for each organization, the user can have one or more roles, like being organization admin, or organization read-only member) (role like orgadmin can also add users for that organization) Now my question is, how should i model the entity of User? If I just take the End User, it can belong to one or more organizations, so each user can contain a set of references to its organizations. But how do we model the users role for each organization, So for example User UX belongs to organizations og1, og2 and og3, and for og1 he is both orgadmin, and org-read-only-user, where as for og2 he is only orgadmin and for og3 he is only org-read-only-user I have the possibility of making each user belong to one organization alone, but that's making the system bounded and I don't like that idea (although i would still satisfy the requirement) If you have a better extensible ACL architecture, please suggest it. Since its a software as a service, one would expect that alot of different organizations would be part if the same system. I had one concern that it is not a good idea to keep og1 and og2 data on the same DB (if og1 decides to spawn a 100 reports on the system, og2 should not suffer) But that is some thing advanced for now and is not directly related to ACL but to the physical distribution of data and setup of services based on those ACLs This is a community Wiki question, please correct any thing which you wish to do so. Thanks

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• Easy way to observe user activity - how improve my database structure.

  - by Thomas

  Welcome, I need some advise to improve perfomence my web application. In the begin I had this structure of database: USER -id (Primary Key) -name -password -email .... PROFILE -user Primary Key, Foreign Key (USER) -birthday -region -photoFile ... PAGES -id (Primary Key) -user Foreign Key(USER) -page -date COMMENTS -id (Primary Key) -user Foreign Key(USER) -page Foreign Key(PAGE) -comment -date FAVOURITES_PAGES -id (Primary Key) -user Foreign Key(USER) -favourite_page Foreign Key(PAGE) -date but now one of the most important page of website is observatory, when everyone can observe activity others users. So I need select all pages, comments and favourites pages some users and display it in one list, sorted by date. For better perfomance (I think) I changed my structure to this: table USER and PROFILE without changes ACTIVITY (additional table- have common fields: user,date) -id (Primary Key) -user Foreign Key(USER) -date -page Foreign Key(PAGE) -comment Foreign Key(COMMENTS) -favourite_page Foreign Key(FAVOURITES_PAGES) PAGES -id (Primary Key) -page COMMENTS -id (Primary Key) -page Foreign Key(PAGE) -comment FAVOURITES_PAGES -id (Primary Key) -favourite_page Foreign Key(PAGE) So now it is very easy get sorted records from all tables. But I have no only foreign key to PAGES, COMMENTS and FAVOURITES_PAGES in ACTIVITY table - there is about ten Foreign Key fields and in one record only one have value, others have None: ACTIVITY id user date page comment ... 1 2 2010-02-23 None 1 2 1 2010-02-21 1 None .... It is corect solution. When I display about 40 records in one page (pagination) I must wait about one secound, but database is almost emty (a few users and about 100 records in others tables). It is depends on amount records per page - I have checked it, but why it takes too long time, becouse of relationships? The website is built in Python/Django. Any advices/opinion?

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• WCF 3.5 Service and multiple http bindings

  - by mortenvpdk

  Hi I can't get my WCF service to work with more than one http binding. In IIS 7 I have to bindings http:/service and http:/service.test both at port 80 In my web.config I have added the baseAddressPrefixFilters but I can't add more than one <serviceHostingEnvironment> <baseAddressPrefixFilters> <add prefix="http://service"/> <add prefix="http://service.test"/> </baseAddressPrefixFilters> </serviceHostingEnvironment> This gives almost the same error "This collection already contains an address with scheme http. There can be at most one address per scheme in this collection. " as if no filers were specified at all (This collection already contains an address with scheme http. There can be at most one address per scheme in this collection. Parameter name: item) If I add only one filter then the service works but only responds on the added filter address. I've also tried with specifing multiple endpoints like (and only one filter): <endpoint address="http://service.test" binding="basicHttpBinding" bindingConfiguration="" contract="IService" /> <endpoint address="http://service" binding="basicHttpBinding" bindingConfiguration="" contract="IService" /> Then still only the address also specified in the filter works and the other returns this error: Server Error in Application "ISPSERVICE" HTTP Error 400.0 - Bad Request Regards Morten

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• Running Magento for multiple clients - single Installaton vs. multiple installations

  - by Chris Hopkins

  Hi There I am looking to set-up a Magento (Community Edition) installation for multiple clients and have researched the matter for a few days now. I can see that the Enterprise Edition has what I need in it, but surprisingly I am not willing to shell out the $12,000 odd yearly subscription. It seems there are a few options available to be but I am worried about the performance I will get out of the various options. Option 1) Single install using AITOC advanced permissions module So this is really what I am after; one installation so that I can update my core files all at the same time and also manage all my store users from one place. The problems here are that I don't know anything about the reliability of this extra product and that I have to pay a bit extra. I am also worried that if I have 10 stores running off this one installation it might all slow down so much and keel over as I have heard allot about Magento's slowness. Module Link: http://www.aitoc.com/en/magentomods_advanced_permissions.html Option 2) Multiple installations of Magento on one server for each shop So here I have 10 Magento installations on one server all running happily away not using any extra money, but I now have 10 separate stores to update and maintain which could be annoying. Also I haven't been able to find a whole lot of other people using this method and when I have they are usually asking how to stop their servers from dying. So this route seems like it could be even worse on my server as I will have more going on on my server but if my server could take it each Magento installation would be simpler and less likely to slow down due to each one having to run 10 shops on its own? Option 3) Use lots of servers and lots of Magento installations I just so do not want to do this. Option 4) Buy Magento Enterprise I do not have the money to do this. So which route is less likely to blow up my server? And does anyone have experience with this holy grail of a module? Thanks for reading and thanks in advance for any help - Chris Hopkins

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• Can you force a crash if a write occurs to a given memory location with finer than page granularity?

  - by Joseph Garvin

  I'm writing a program that for performance reasons uses shared memory (alternatives have been evaluated, and they are not fast enough for my task, so suggestions to not use it will be downvoted). In the shared memory region I am writing many structs of a fixed size. There is one program responsible for writing the structs into shared memory, and many clients that read from it. However, there is one member of each struct that clients need to write to (a reference count, which they will update atomically). All of the other members should be read only to the clients. Because clients need to change that one member, they can't map the shared memory region as read only. But they shouldn't be tinkering with the other members either, and since these programs are written in C++, memory corruption is possible. Ideally, it should be as difficult as possible for one client to crash another. I'm only worried about buggy clients, not malicious ones, so imperfect solutions are allowed. I can try to stop clients from overwriting by declaring the members in the header they use as const, but that won't prevent memory corruption (buffer overflows, bad casts, etc.) from overwriting. I can insert canaries, but then I have to constantly pay the cost of checking them. Instead of storing the reference count member directly, I could store a pointer to the actual data in a separate mapped write only page, while keeping the structs in read only mapped pages. This will work, the OS will force my application to crash if I try to write to the pointed to data, but indirect storage can be undesirable when trying to write lock free algorithms, because needing to follow another level of indirection can change whether something can be done atomically. Is there any way to mark smaller areas of memory such that writing them will cause your app to blow up? Some platforms have hardware watchpoints, and maybe I could activate one of those with inline assembly, but I'd be limited to only 4 at a time on 32-bit x86 and each one could only cover part of the struct because they're limited to 4 bytes. It'd also make my program painful to debug ;)

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• Best and easiest algorithm to search for a vertex on a Graph?

  - by Nazgulled

  Hi, After implementing most of the common and needed functions for my Graph implementation, I realized that a couple of functions (remove vertex, search vertex and get vertex) don't have the "best" implementation. I'm using adjacency lists with linked lists for my Graph implementation and I was searching one vertex after the other until it finds the one I want. Like I said, I realized I was not using the "best" implementation. I can have 10000 vertices and need to search for the last one, but that vertex could have a link to the first one, which would speed up things considerably. But that's just an hypothetical case, it may or may not happen. So, what algorithm do you recommend for search lookup? Our teachers talked about Breadth-first and Depth-first mostly (and Dikjstra' algorithm, but that's a completely different subject). Between those two, which one do you recommend? It would be perfect if I could implement both but I don't have time for that, I need to pick up one and implement it has the first phase deadline is approaching... My guess, is to go with Depth-first, seems easier to implement and looking at the way they work, it seems a best bet. But that really depends on the input. But what do you guys suggest?

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• How can I filter these Django records?

  - by mipadi

  I have a set of Django models as shown in the following diagram (the names of the reverse relationships are shown in the yellow bubbles): In each relationship, a Person may have 0 or more of the items. Additionally, the slug field is (unfortunately) not unique; multiple Person records may have the same slug fields. Essentially these records are duplicates. I want to obtain a list of all records that meet the following criteria: All duplicate records (that is, having the same slug) with at least one Entry OR at least one Audio OR at least one Episode OR at least one Article. So far, I have the following query: Person.objects.values('slug').annotate(num_records=Count('slug')).filter(num_records__gt=1) This groups all records by slug, then adds a num_records attribute that says how many records have that slug, but the additional filtering is not performed (and I don't even know if this would work right anyway, since, given a set of duplicate records, one may have, e.g., and Entry and the other may have an Article). In a nutshell, I want to find all duplicate records and collapse them, along with their associated models, into one record. What's the best way to do this with Django?

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• Building a many-to-many db schema using only an unpredictable number of foreign keys

  - by user1449855

  Good afternoon (at least around here), I have a many-to-many relationship schema that I'm having trouble building. The main problem is that I'm only working with primary and foreign keys (no varchars or enums to simplify things) and the number of many-to-many relationships is not predictable and can increase at any time. I looked around at various questions and couldn't find something that directly addressed this issue. I split the problem in half, so I now have two one-to-many schemas. One is solved but the other is giving me fits. Let's assume table FOO is a standard, boring table that has a simple primary key. It's the one in the one-to-many relationship. Table BAR can relate to multiple keys of FOO. The number of related keys is not known beforehand. An example: From a query FOO returns ids 3, 4, 5. BAR needs a unique key that relates to 3, 4, 5 (though there could be any number of ids returned) The usual join table does not work: Table FOO_BAR primary_key | foo_id | bar_id | Since FOO returns 3 unique keys and here bar_id has a one-to-one relationship with foo_id. Having two join tables does not seem to work either, as it still can't map foo_ids 3, 4, 5 to a single bar_id. Table FOO_TO_BAR primary_key | foo_id | bar_to_foo_id | Table BAR_TO_FOO primary_key | foo_to_bar_id | bar_id | What am I doing wrong? Am I making things more complicated than they are? How should I approach the problem? Thanks a lot for the help.

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