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  • How to return model state from child action handler in ASP.NET MVC

    - by Joe Future
    In my blog engine, I have one controller action that displays blog content, and in that view, I call Html.RenderAction(...) to render the "CreateComment" form. When a user posts a comment, the post is handled by the comment controller (not the blog controller). If the comment data is valid, I simply return a Redirect back to the blog page's URL. If the comment data is invalid (e.g. comment body is empty), I want to return the ViewData with the error information back to the blog controller and through the blog view to the CreateComment action/view so I can display which fields are bad. I have this working fine via AJAX when Javascript is enabled, but now I'm working on the case where Javascript might be disabled. If I return a RedirecToAction or Redirect from the comment controller, the model state information is lost. Any ideas?

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  • Fluent nHibernate and mapping IDictionary<DaysOfWeek,IDictionay<int, decimal>> how to?

    - by JS Future Software
    Hello, I have problem with making mapping of classes with propert of type Dictionary and value in it of type Dictionary too, like this: public class Class1 { public virtual int Id { get; set; } public virtual IDictionary<DayOfWeek, IDictionary<int, decimal>> Class1Dictionary { get; set; } } My mapping looks like this: Id(i => i.Id); HasMany(m => m.Class1Dictionary); This doesn't work. The important thing I want have everything in one table not in two. WHet I had maked class from this second IDictionary I heve bigger problem. But first I can try like it is now.

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  • ASP.NET MVC application architecture "guidelines"

    - by Joe Future
    I'm looking for some feedback on my ASP.NET MVC based CMS application architecture. Domain Model - depends on nothing but the System classes to define types. For now, mostly anemic. Repository Layer - abstracted data access, only called by the services layer Services Layer - performs business logic on domain models. Exposes view models to the controllers. ViewModelMapper - service that translates back and forth between view models and domain models Controllers - super thin "traffic cop" style functionality that interacts with the service layer and only talks in terms of view models, never domain models My domain model is mostly used as data transfer (DTO) objects and has minimal logic at the moment. I'm finding this is nice because it depends on nothing (not even classes in the services layer). The services layer is a bit tricky... I only want the controllers to have access to viewmodels for ease of GUI programming. However, some of the services need to talk to each other. For example, I have an eventing service that notifies other listener services when content is tagged, when blog posts are created, etc. Currently, the methods that take domain models as inputs or return them are marked internal so they can't be used by the controllers. Sounds like overkill? Not enough abstraction? I'm mainly doing this as a learning exercise in being strict about architecture, not for an actual product, so please no feedback along the lines of "right depends on what you want to do". thanks! Jason

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  • Castle Dynamic Proxy is it possible to intercept value types?

    - by JS Future Software
    Hi, I have a problem and can not find answer and any tip if it is possible to intercept value types in C# by Castle dynamic proxy? I want to intercept IDictionary with INotifyChanged interface. I need this to update view when presenter is changing model. Boxing decimal in object only for making interface is not good idea... maybe somebody have idea how to intrcept value types? Thanks to all answers

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  • Opinion on "loop invariants", and are these frequently used in the industry?

    - by Michael Aaron Safyan
    I was thinking back to my freshman year at college (five years ago) when I took an exam to place-out of intro-level computer science. There was a question about loop invariants, and I was wondering if loop invariants are really necessary in this case or if the question was simply a bad example... the question was to write an iterative definition for a factorial function, and then to prove that the function was correct. The code that I provided for the factorial function was as follows: public static int factorial(int x) { if ( x < 0 ){ throw new IllegalArgumentException("Parameter must be = 0"); }else if ( x == 0 ){ return 1; }else{ int result = 1; for ( int i = 1; i <= x; i++ ){ result*=i; } return result; } } My own proof of correctness was a proof by cases, and in each I asserted that it was correct by definition (x! is undefined for negative values, 0! is 1, and x! is 1*2*3...*x for a positive value of x). The professor wanted me to prove the loop using a loop invariant; however, my argument was that it was correct "by definition", because the definition of "x!" for a positive integer x is "the product of the integers from 1... x", and the for-loop in the else clause is simply a literal translation of this definition. Is a loop invariant really needed as a proof of correctness in this case? How complicated must a loop be before a loop invariant (and proper initialization and termination conditions) become necessary for a proof of correctness? Additionally, I was wondering... how often are such formal proofs used in the industry? I have found that about half of my courses are very theoretical and proof-heavy and about half are very implementation and coding-heavy, without any formal or theoretical material. How much do these overlap in practice? If you do use proofs in the industry, when do you apply them (always, only if it's complicated, rarely, never)?

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  • The Importance of a Security Assessment - by Michael Terra, Oracle

    - by Darin Pendergraft
    Today's Blog was written by Michael Terra, who was the Subject Matter Expert for the recently announced Oracle Online Security Assessment. You can take the Online Assessment here: Take the Online Assessment Over the past decade, IT Security has become a recognized and respected Business discipline.  Several factors have contributed to IT Security becoming a core business and organizational enabler including, but not limited to, increased external threats and increased regulatory pressure. Security is also viewed as a key enabler for strategic corporate activities such as mergers and acquisitions.Now, the challenge for senior security professionals is to develop an ongoing dialogue within their organizations about the importance of information security and how it can impact their organization's strategic objectives/mission. The importance of conducting regular “Security Assessments” across the IT and physical infrastructure has become increasingly important. Security standards and frameworks, such as the international standard ISO 27001, are increasingly being adopted by organizations and their business partners as proof of their security posture and “Security Assessments” are a great way to ensure a continued alignment to these frameworks.Oracle offers a number of different security assessment covering a broad range of technologies. Some of these are short engagements conducted for free with our strategic customers and partners. Others are longer term paid engagements delivered by Oracle Consulting Services or one of our partners. The goal of a security assessment, (also known as a security audit or security review), is to ensure that necessary security controls are integrated into the design and implementation of a project, application or technology.  A properly completed security assessment should provide documentation outlining any security gaps that exist in an infrastructure and the associated risks for those gaps. With that knowledge, an organization can choose to either mitigate, transfer, avoid or accept the risk. One example of an Oracle offering is a Security Readiness Assessment:The Oracle Security Readiness Assessment is a practical security architecture review focused on aligning an organization’s enterprise security architecture to their business principals and strategic objectives. The service will establish a multi-phase security architecture roadmap focused on supporting new and existing business initiatives.Offering OverviewThe Security Readiness Assessment will: Define an organization’s current security posture and provide a roadmap to a desired future state architecture by mapping  security solutions to business goals Incorporate commonly accepted security architecture concepts to streamline an organization’s security vision from strategy to implementation Define the people, process and technology implications of the desired future state architecture The objective is to deliver cohesive, best practice security architectures spanning multiple domains that are unique and specific to the context of your organization. Offering DetailsThe Oracle Security Readiness Assessment is a multi-stage process with a dedicated Oracle Security team supporting your organization.  During the course of this free engagement, the team will focus on the following: Review your current business operating model and supporting IT security structures and processes Partner with your organization to establish a future state security architecture leveraging Oracle’s reference architectures, capability maps, and best practices Provide guidance and recommendations on governance practices for the rollout and adoption of your future state security architecture Create an initial business case for the adoption of the future state security architecture If you are interested in finding out more, ask your Sales Consultant or Account Manager for details.

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  • SOA Summit - Oracle Session Replay

    - by Bruce Tierney
    If you think you missed the most recent Integration Developer News (IDN) "SOA Summit" 2013...good news, you didn't.  At least not the replay of the Oracle session titled: Three Solutionsfor Simplifying Cloud/On-Premises Integration As you will see in the reply below, this session introduces Three common reasons for integration complexity: Disparate Toolkits Lack of API Management Rigid, Brittle Infrastructure and then the Three solutions to these challenges: Unify Cloud On-premises Integration Enable Multi-channel Development with API Management Plan for the Unexpected - Future Readiness The last solution on future readiness describes how you can transition from being reactive to new trends, such as the Internet of Things (IoT), by modifying your integration strategy to enable business agility and how to recognize trends through Fast Data event processing ahead of your competition. Oracle SOA Suite customer SFpark's (San Francisco Metropolitan Transit Authority) implementation with API Management is covered as shown in the screenshot to the right This case study covers the core areas of API Management for partners to build their own applications by leveraging parking availability and real-time pricing as well as mobile enablement of data integrated by SOA Suite underneath.  Download the free SFpark app from the Apple and Android app stores to check it out. When looking into the future, the discussion starts with a historical look to better prepare for what comes next.   As shown in the image below, one of the next frontiers after mobile and cloud integration is a deeper level of direct "enterprise to customer" interaction.  Much of this relates to the Internet of Things.  Examples of IoT from the perspective of SOA and integration is also covered in the session. For example, early adopter Turkcell and their tracking of mobile phone users as they move from point A to B to C is shown in the image the right.   As you look into more "smart services" such as Location-Based Services, how "future ready" is your application infrastructure?  . . . Check out the replay by clicking the video image below to learn about these three challenges and solution including how to "future ready" your application infrastructure:

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  • Advice needed: stay with Java team or move to C++ team?

    - by user68759
    Some background - I have been programming in Java as a professional for the last few years. This is mainly using Java SE. I have also touched bits and pieces of other various Java technologies and have some basic knowledge about them. I consider my self as an intermediate Java programmer. I like Java very much. I think it is only going to get bigger. Recently, my manager asked my opinion on whether I would like to be transferred to another team within the company that is developing a product in C++. This is mainly because my current Java team simply didn't make enough money due to poor sales and the economic downturn. Now, I have never had any experience with C++ nor have I ever coded a single line of code in C++. I have always wanted to learn it and now is my chance. But I really want to make sure I get benefit out of it in the future, in the sense that I will have the skills that will still be on-demand in the future. So, what do you experts think? Is C++ still the language to learn these days to secure yourself for the future? What will I learn more in C++ but not in Java? And are they worthy to learn considering the current and possible future demands in IT industry? (Apart from the obvious more control over memory management and something along that line.) What is a good excuse to refuse the offer in order to stay with the Java team? I don't want to blatantly refuse it because you can never predict the future and I could possibly come back to my manager in the future and ask him to transfer me to the C++ team. How do I say it nicely that I am taking the offer but I would like to still be involved with Java one way or another, such as when there is a new Java project I would like to be considered. I have to admit that I am kind of 50-50 at the moment. I want to learn C++ for the sake of improving my skills and also helping my company to reduce the fund required for the Java team. But it is also hard for me to leave Java because I know Java is going to get bigger, so I am afraid of getting behind when I start concentrating on C++. I could, of course, decide to just join the C++ team, and then spend my free time reading about Java to keep in touch with it, but I thought I would ask anyway in case some people can point out the strong points of either over the other given the current and possibly future circumstances.

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  • Summary of the Solaris 11 webcast's livechat QnA session

    - by Karoly Vegh
    This is a followup post to the previous summary on the "What's new with Solaris 11 since the launch" webcast. That webcast has had a chatroom for a live Questions and Answers session running. I went through the archive of those and compiled a list of some of the (IMHO) most relevant and most frequently asked questions, I'd like to share. This is the first part, covering the QnA of Session I and II of the webcast, in a followup post we can have a look of the rest of the sessions if required - let me know in the comments. Also, should you have questions, as usual, feel free to ask those there, too.  ...and here come the answered questions:  When will Exadata be based on Solaris in place of Oracle Enterprise Linux?Exadata offers both Solaris 11 or Oracle Enterprise Linux.  The choice can be made at deployment time based on your OS needs.What are all other benefits and futures avilable in solaris 11 (cloud O.S.) compared to cloud based Red Hat Linux and Windows?suggest you check out our cloud white paper for a view of this. Also the OTN Solaris 11 page has some good articles. Here are the links:  http://www.oracle.com/technetwork/server-storage/solaris11/documentation/o11-106-sol11-cloud-501066.pdf http://www.oracle.com/technetwork/server-storage/solaris11/overview/index.htmlWill 11.1 have a more complete IPS respository for Oracle and FOSS software?Yes, we are adding additional packages to the various package repositories. Since Solaris 11 was launched, both the Oracle Solaris Studio tools as well as Oracle Solaris Cluster have been made available along with numerous new FOSS packages. We will continue to be adding additional Oracle products and open source packages in the future. Will Exadata be based on Sparc in place of intel-amd x86 in next future ?We can't publically discuss futures, but we actually have a SPARC version of Exadata today, it's called SuperCluster, this is such a powerfull multipurpose system that it actually have multiple personalities built into one system: Exadata, Exalogic, and it can be a general purpose platform if you want. Have I understood this right? Livepatching KSplice-style is coming to Solaris 11 too?We're looking at that for certain types of Solaris patches in the future.Will there be a security framework like SST/JASS for Solaris 11?We can't talk about the future projects on a public forum, but we recognize the need for SST/JASS and want to address this as soon as possible. On the other side there are a whole bunch of "best practices" that are now embedded into Solaris 11 by default, so out of the box Solaris 11 should already address part of what SST/JASS gave you. (For example we did a lot of work on improving the auditing performance so that we can now have it turned on by default). On x86 can install VirtualBox in a Zone and use that to host other OSes.Yes, this was one of the first things we made sure would work when we acquired VirtualBox when we were still Sun Microsystems. If I have a Solaris 11 Control Domain on a T-series, can I run a Solaris 10 Ldom with Solaris 8 branded containers?Yes, you can.Is Oracle Solaris free or do we need to purchase?Solaris is free, the entitlement to run it comes either with a Sun system (new or historical) or for 3rd party systems the entitlement comes with a support contract. Note that for production use you will be expected to get a support contract. If you don't want to use the Solaris system (Sun or 3rd party) for production use (i.e. development) you can get an OTN license on the Oracle Technical Network website. Will encryption and deduplication both work on a share?This should work at the same time. What approaches does Solaris use to monitor usage?There are many different tools in Solaris to monitor usage. The main ones are the "stats" (vmstat, mpstat, prstat, ...), the kstat interface, and DTrace (to get details you couldn't see before). And then there are layered tools that can interface with these tools (Ops Center, BMC, CA, Tivoli, ...) Apart little-endian, big-endian how is it easy to port Solaris applications on Sparc to x86 and vice-versa ?Very easy. Except for certain hardware specific applications (those that utilize hardware specific drivers), all of the same Oracle Solaris APIs exist for all architectures. Is IPS based patching aware of the fact that zones can reside on ZFS and move from one physical server to another ?IPS is definitely aware of zones and uses ZFS to support boot environments for non-global zones in the same way that's used for the global zone. With respect to moving a zone from one physical server to another, Solaris 11 supports to the same zone attach/deattach method that was introduced in Solaris 10. Is vnic support in Ldoms planned?This is currently being investigated for a future LDOM release. Is it possible with the new patching system to build a system later with the same patch level as a system built a few months earlier?Yes, you can choose/define exactly which version should go to the system and it will always put the same bits in place. The technical answer is that you choose the version of the "entire" package you want on the system and the rest flows from there. Is it in the plans to allow zones to add/remove zpools to running zones dynamically in future updates?Work in this area is currently under investigation. Any plans to realese Solaris 11 source code? i.e. opensolaris?We currently can't comment on publicly releasing the source code. If you need/want this access please let your Oracle account team know. What about VirtualBox and Solaris11 for virtualization?Solaris 11 works great with VirtualBox, as both a client and a host system. Will Oracle DB software eventually be supplied as IPS packages? When?We don't have a date yet but this is actively being worked on. What are the new artifacts in Oracle Solaris 11 than the previous versions?There are quite a few actually. The best start is to look at our "Evaluate Solaris 11" page, and there you also can find a Transition Guide. http://www.oracle.com/technetwork/server-storage/solaris11/overview/evaluate-1530234.html So, this seems just like RedHat's YUM environment?IPS offers certain features beyond those in YUM or other packaging systems. For example, IPS works with ZFS and Solaris Boot Environments to provide a safe environment for software lifecycle management so that changes can be reverted by switching to an older boot environment. With Zones on solaris 11, can I do paravirtualitation?The great thing about zones is you don't *need* paravirtualization. You're making the same direct kernel calls that you would outside of a zone.  It's an incredibly significant performance win over hypervisor-based virtualization. Are zones/containers officially supported to run Oracle Databases?  EBIZ?Hi Calvin, the answer is yes, here is the support matrix for DB:  http://www.oracle.com/technetwork/database/virtualizationmatrix-172995.html I've found some nasty bugs in Solaris 11 (one of which today) that have been fixed in community forks (i.e., Illumos). Will Oracle ever restart collaboration with the community?We continue to work with the community, just not as open on all projects as we did before (For example IPS is an open project) and the source of more than half of the Solaris packages is posted on our opensource websites. I can't comment on what we will do in the future. And with regards to bugs please file them through the support organization and we will get them resolved. Is zpool vdev removal on-the fly now possible ?This issue is actively being investigated although we don't have a date for when this feature will be available. Is pgstat now the official replacement for corestat ?It's intended to provide similar functionality Where are the opensource website?For Oracle Solaris, visit http://www.oracle.com/technetwork/opensource/systems-solaris-1562786.html As a cloud-scale virtualization, is it going to be easier to move zones between machines? maybe even automatic in case of a hardware failure?Hi Gashaw, we already have customers that have implemented what they refer to as "flying zones" that they can move around very easily. They use Solaris Cluster to do this. What about VMware vMotion like feature?We have secure live migration with both Logical Domains on SPARC T series systems, and with Oracle VM on x86 systems. When running Solaris 10/11 on an enterprise server with a lot of zones, what are best practises commands to show the system is running fine? (has enough hardware resources). For example CPU / Memory / I/O / system load. What are the recommended values?For Solaris 11, look into the new zonestat(1M) command that provides a great deal of information about zone utilization. In addition, there is new work underway in providing additional observability in areas such as per-zone file system I/O. Java optimizations done with Solaris 11? For X86 platforms too? Where can I find more detail about this?There is lots of work that go into optimizing Java for Oracle Solaris 10 & 11 on both SPARC and x86. See http://www.oracle.com/technetwork/articles/servers-storage-dev/solarisforjavadevelop-168642.pdf What is meant by "ZFS Shadow Migration"?It's a way to migrate data from another file system to ZFS: http://docs.oracle.com/cd/E23824_01/html/E24456/filesystem-3.html Is flash archive available with S11?Flash archive is not.  There is a procedure for disaster recovery, and we're working on a modern archive-based deployment tool for a future update.  The disaster recovery tool is here: http://www.oracle.com/technetwork/articles/servers-storage-admin/o11-091-sol-dis-recovery-489183.html  You can also use Distribution Constructor to build common golden images. Will solaris 11 be available on the ODA soon?The idea's under evaluation -- we'll share your interest with the team. What steps can be taken to ensure that breaches of security are identified quickly?There are a number of tools, including the "bart" tool and "pkg verify" to ensure that software has not been compromised.  Solaris Audit can also be used to detect unauthorized access.  You can also use Immutable Zones to protect against compromise.  There are a wide variety of security tools, and I've covered only a few. What is the relation from solaris to java 7 speed optimization?There is constant work done between the Oracle Solaris and Java teams on performance optimizations. See http://docs.oracle.com/javase/7/docs/technotes/guides/vm/performance-enhancements-7.html for examples. What is the difference in the Solaris 11 installation compared to solaris 10 ? where i can find the document describing basic repository concepts ?The best place to start is: http://www.oracle.com/technetwork/server-storage/solaris11/index.html Hope you found the post useful. For questions, input, requests for the second half of the QnA, please find the comment section below.  -- charlie  

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  • What I saw at TechEd North America 2014

    - by Brian Schroer
    Originally posted on: http://geekswithblogs.net/brians/archive/2014/05/19/teched-north-america-2014.aspxI was thrilled to be able to attend TechEd North America 2014 in Houston last week. I got to go to Orlando in 2008, and since then I’ve had to settle for watching the sessions online (which ain’t bad – They’re all available on Channel 9 for streaming or downloading. Here are links to the Developer Track sessions and to the sessions from all tracks.) The sessions I attended (with my favorites bolded) were: Shiny new stuff The Microsoft Application Platform for Developers: Create Applications That Span Devices and Services INTRODUCING: The Future of .NET on the Server DEEP DIVE: The Future of .NET on the Server ASP.NET: Building Web Application Using ASP.NET and Visual Studio The Next Generation of .NET for Building Applications The Future of Visual Basic and C# Stuff you can use now Building Rich Apps with AngularJS on ASP.NET Get the Most Out of Your Code Maps SignalR: Building Real-Time Applications with ASP.NET SignalR Performance Optimize Your ASP.NET Web App Modern Web and Visual Studio Visual Studio Power User: Tips and Tricks Debugging Tips and Tricks in Visual Studio 2013 In a world where the whole company uses TFS… Using Functional, Exploratory and Acceptance Testing to Release with Confidence A Practical View of Release Management for Visual Studio 2013 From Vanity to Value, Metrics That Matter: Improving Lean and Agile, Kanban, and Scrum Ain’t Nobody Got Time for That As usual, there were some time slots with nothing of interest and others with 5 things I wanted to see at the same time. Here are the sessions I’m still planning to watch… Getting Started with TypeScript Building a Large Scale JavaScript Application in TypeScript Modern Application Lifecycle Management Why a Hacker Can Own Your Web Servers in a Day! Async Best Practices for C# and Visual Basic Building Multi-Device Apps with the New Visual Studio Tooling for Apache Cordova Applying S.O.L.I.D. Principles in .NET/C# Native Mobile Application Development for iOS, Android, and Windows in C# and Visual Studio Using Xamarin Latest Innovations in Developing ASP.NET MVC Web Applications Zero to Hero: Untested to Tested with Microsoft Fakes Using Visual Studio Cool and Elegant ASP.NET Web Forms with HTML 5 for the Modern Web The Present and Future of .NET in a World of Devices and Services

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  • Is Master Data Management CRM's Secret Sauce?

    - by divya.malik
    This was the title of a recent blog entry by our colleagues in EMEA. Having a good master data management system enables organizations to get a unified, accurate and complete understanding of their customers. Gartner Group's John Radcliffe explains why MDM is destined to be at the heart of future CRM and social CRM projects. Experts are predicting big things for master data management (MDM) in the immediate future. While far from being a new kid on the block, its potential benefits at a time when organisations are drowning in data mean that it is in the right place at the right time. "MDM is not 'nice to have'," explains John Radcliffe, research vice president at Gartner. "If tackled in the right way it can provide near term business value that plays into an organisation's new focus on cost efficiencies, risk management and regulatory compliance, while supporting growth and future transformative strategies." The complete article can be found here.

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  • What's the best practice for async APIs that return futures on Scala?

    - by Maurício Linhares
    I have started a project to write an async PostgreSQL driver on Scala and to be async, I need to accept callbacks and use futures, but then accepting a callback and a future makes the code cumbersome because you always have to send a callback even if it is useless. Here's a test: "insert a row in the database" in { withHandler { (handler, future) => future.get(5, TimeUnit.SECONDS) handler.sendQuery( this.create ){ query => }.get( 5, TimeUnit.SECONDS ) handler.sendQuery( this.insert ){ query => }.get( 5, TimeUnit.SECONDS ).rowsAffected === 1 } } Sending the empty callback is horrible but I couldn't find a way to make it optional or anything like that, so right now I don't have a lot of ideas on how this external API should look like. It could be something like: handler.sendQuery( this.create ).addListener { query => println(query) } But then again, I'm not sure how people are organizing API's in this regard. Providing examples in other projects would also be great.

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  • using an already proved lema/theorem/corollary in coq

    - by André Hincu
    I am trying to make a proof in Coq, and I would like to use a lemma already definded and proved by me. Is it possible for the following code? Lemma conj_comm: forall A B : Prop, A /\ B -> B /\ A. Proof. intros. destruct H. split. exact H0. exact H. Qed. Lemma not_conj_comm: forall A B : Prop, ~(A /\ B) -> ~(B /\ A). Proof. intros. intro. unfold not in H. apply H. use H0. In the above I want to use the fact that A /\B is the same as B /\ A in order to prove that ~(A /\ B) is the same as ~(B /\ A). Is it possible to use my proved lemma?

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  • Formal Languages, Inductive Proofs &amp; Regular Expressions

    - by MarkPearl
    So I am slogging away at my UNISA stuff. I have just finished doing the initial once non stop read through the first 11 chapters of my COS 201 Textbook - “Introduction to Computer Theory 2nd Edition” by Daniel Cohen. It has been an interesting couple of days, with familiar concepts coming up as well as some new territory. In this posting I am going to cover the first couple of chapters of the book. Let start with Formal Languages… What exactly is a formal language? Pretty much a no duh question for me but still a good one to ask – a formal language is a language that is defined in a precise mathematical way. Does that mean that the English language is a formal language? I would say no – and my main motivation for this is that one can have an English sentence that is correct grammatically that is also ambiguous. For example the ambiguous sentence: "I once shot an elephant in my pyjamas.” For this and possibly many other reasons that I am unaware of, English is termed a “Natural Language”. So why the importance of formal languages in computer science? Again a no duh question in my mind… If we want computers to be effective and useful tools then we need them to be able to evaluate a series of commands in some form of language that when interpreted by the device no confusion will exist as to what we were requesting. Imagine the mayhem that would exist if a computer misinterpreted a command to print a document and instead decided to delete it. So what is a Formal Language made up of… For my study purposes a language is made up of a finite alphabet. For a formal language to exist there needs to be a specification on the language that will describe whether a string of characters has membership in the language or not. There are two basic ways to do this: By a “machine” that will recognize strings of the language (e.g. Finite Automata). By a rule that describes how strings of a language can be formed (e.g. Regular Expressions). When we use the phrase “string of characters”, we can also be referring to a “word”. What is an Inductive Proof? So I am not to far into my textbook and of course it starts referring to proofs and different types. I have had to go through several different approaches of proofs in the past, but I can never remember their formal names , so when I saw “inductive proof” I thought to myself – what the heck is that? Google to the rescue… An inductive proof is like a normal proof but it employs a neat trick which allows you to prove a statement about an arbitrary number n by first proving it is true when n is 1 and then assuming it is true for n=k and showing it is true for n=k+1. The idea is that if you want to show that someone can climb to the nth floor of a fire escape, you need only show that you can climb the ladder up to the fire escape (n=1) and then show that you know how to climb the stairs from any level of the fire escape (n=k) to the next level (n=k+1). Does this sound like a form of recursion? No surprise then that in the same chapter they deal with recursive definitions. An example of a recursive definition for the language EVEN would the 3 rules below: 2 is in EVEN If x is in EVEN then so is x+2 The only elements in the set EVEN are those that be produced by the rules above. Nothing to exciting… So if a definition for a language is done recursively, then it makes sense that the language can be proved using induction. Regular Expressions So I am wondering to myself what use is this all – in fact – I find this the biggest challenge to any university material is that it is quite hard to find the immediate practical applications of some theory in real life stuff. How great was my joy when I suddenly saw the word regular expression being introduced. I had been introduced to regular expressions on Stack Overflow where I was trying to recognize if some text measurement put in by a user was in a valid form or not. For instance, the imperial system of measurement where you have feet and inches can be represented in so many different ways. I had eventually turned to regular expressions as an easy way to check if my parser could correctly parse the text or not and convert it to a normalize measurement. So some rules about languages and regular expressions… Any finite language can be represented by at least one if not more regular expressions A regular expressions is almost a rule syntax for expressing how regular languages can be formed regular expressions are cool For a regular expression to be valid for a language it must be able to generate all the words in the language and no other words. This is important. It doesn’t help me if my regular expression parses 100% of my measurement texts but also lets one or two invalid texts to pass as well. Okay, so this posting jumps around a bit – but introduces some very basic fundamentals for the subject which will be built on in later postings… Time to go and do some practical examples now…

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  • Interviews Gone Bad.....Now What Do I Do?

    - by david.talamelli
    We have all done it at some stage of our working careers - you know those times when you leave an interview and then you think to yourself "why didn't I ask that question" or "I can't believe I said that" or "how could I have forgotten to say that". It happens to everyone but how you handle things moving forwards could be critical in helping you land that dream job. There is nothing better than seeing that dream job with the dream company that you are looking to work for advertised (or in some cases getting called by the Recruiter to let you know about that job). The role may seem perfect and it could be just what you are looking for and it is with the right company as well. You have sent in your resume and have subsequently had one, two or maybe three interviews for the role. After each step of the process you get a little bit more excited about the role as you start to think about your work day in your new role/company. Then it happens, you get it: you get The Phone Call to inform you that you have not been successful in securing the position that you have invested so much time and effort into. It can be disappointing to hear this news but what you do next is important in potentially keeping that door open for future opportunities with that company. How you handle yourself in this situation is important: if any of you remember the Choose Your Own Adventure Books do you: Tell the Recruiter (maybe get aggressive) they are wrong in their assessment and that you are the right candidate for the role Switch off and say ok thanks and hang up without engaging in any further dialogue Thank the company for their time and enquire if there may be any other opportunities in the future to explore If you chose the first option - the company in question may consider whether or not to look at you for other opportunities. How you handle yourself in the recruitment process could be an indication of how you would deal with clients/colleagues in your role and the impression that you leave a potential employer may be what sticks in their mind when they think of you (eg: isn't that the person who couldn't handle it when we told him he wasn't right for our role). The second option potentially produces a similar outcome. If you rush to get off the phone, the company may come back to you to talk about other roles when they come up, but you also leave open the potential thought with the company you were only interested in that role and therefore not interested in any other opportunities. Why take the risk of the company thinking that and potentially not getting back to you in the future. By picking the third option, you actively engage with the company and keep the dialogue open for future discussions. Ok, so you didn't get the role you interviewed for - you don't know who else the company may have been interviewing - maybe they found someone who was a better fit, or maybe there were too many boxes you didn't tick to step straight into that specific role. Take a deep breath and keep the company engaged. You are fresh in their mind - take advantage of that fact and let them know that while you respect their decision, that you are still interested in the company and would like to be kept in mind for future roles. Ask if it is ok to keep in touch and when they would like to keep in touch, as long as you are interested let them know you are still interested. You do need to balance that though if you come across as too keen or start stalking people - it could equally damage your brand. Companies normally have more than one open role. New roles are created all the time, circumstances change and hiring people is not a static business, it changes course from everyone's best laid initial plans. If you didn't get that initial role you wanted, keep the door open with that company so that when those new roles do come up or when circumstances do change you have already laid the ground to step into those new positions.

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  • Adobe publie deux méthodes pour contrer l'exploitation de PDF malicieux mise à jour la semaine derni

    Mise à jour du 08/04/10 Adobe publie deux méthodes pour contrer l'exploitation de PDF malicieux Mise à jour la semaine dernière dans un "proof of concept" Suite au "proof of concept" (POC) de Didier Stevens qui montrait comment réaliser une attaque en utilisant un PDF malicieux (une méthode qui, en ce qui concerne Adobe, impliquait une forte part d'"ingénierie sociale", autrement dit de manipulation de l'utilisateur par l'affichage d'un message modifiée) , Adobe a décidé d'apporter des modifications à ses applications (Acrobat et Reader). En attendant que celles-ci soient effectives, la société vient d'éd...

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  • Website content copied - How can I prove that I wrote it?

    - by Remy
    One of our competitors constantly copies all our website content. Now, I assume the trouble is to proof that we wrote the content first and that it is not the other way round. I checked on http://www.archive.org, but there is nothing. Any other way to proof that? FYI: We are a swiss company, so different laws will apply. Solution: [Found later] You can upload your content to this service and that they basically timestamp it. https://myows.com/ Another way we found, is to just print out your copy/design, etc. put it into an envelop and send it to ourself (without actually opening it later of course).

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  • Should I pay for my training? [closed]

    - by user65883
    I work at a company that made me sign a contract to pay for my training should I decide to leave within my 3 months probation. I never went on a formal course and didn't get any proof of undergoing the course. They stated if I don't sign the contract then I wouldn't receive training and I won't be able to do my job. If their training is to watch what other employees do then I took the course. I'm wondering if it's allowed for them to ask me for money when I didn't receive any proof of training?

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  • Restrict dates in 'datetimepicker' in C#

    - by Jordan-C
    A feature of a forms based application I am developing allows the user to search through a history of records. The user can search by name, by number, and between dates, and populate the results in a datagridview control. However, as the form will be used to search for previous records. The ability for the user to select future dates is not required. Is there a way to prevent the user from selecting future dates, or even grey the future dates out?

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  • Java Performance measurement

    - by portoalet
    Hi, I am doing some Java performance comparison between my classes, and wondering if there is some sort of Java Performance Framework to make writing performance measurement code easier? I.e, what I am doing now is trying to measure what effect does it have having a method as "synchronized" as in PseudoRandomUsingSynch.nextInt() compared to using an AtomicInteger as my "synchronizer". So I am trying to measure how long it takes to generate random integers using 3 threads accessing a synchronized method looping for say 10000 times. I am sure there is a much better way doing this. Can you please enlighten me? :) public static void main( String [] args ) throws InterruptedException, ExecutionException { PseudoRandomUsingSynch rand1 = new PseudoRandomUsingSynch((int)System.currentTimeMillis()); int n = 3; ExecutorService execService = Executors.newFixedThreadPool(n); long timeBefore = System.currentTimeMillis(); for(int idx=0; idx<100000; ++idx) { Future<Integer> future = execService.submit(rand1); Future<Integer> future1 = execService.submit(rand1); Future<Integer> future2 = execService.submit(rand1); int random1 = future.get(); int random2 = future1.get(); int random3 = future2.get(); } long timeAfter = System.currentTimeMillis(); long elapsed = timeAfter - timeBefore; out.println("elapsed:" + elapsed); } the class public class PseudoRandomUsingSynch implements Callable<Integer> { private int seed; public PseudoRandomUsingSynch(int s) { seed = s; } public synchronized int nextInt(int n) { byte [] s = DonsUtil.intToByteArray(seed); SecureRandom secureRandom = new SecureRandom(s); return ( secureRandom.nextInt() % n ); } @Override public Integer call() throws Exception { return nextInt((int)System.currentTimeMillis()); } } Regards

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  • How extensible should code actually be?

    - by griegs
    I've just started a new job and one of the things my new boss talked to me about was code longevity. I've always coded to make my code infinently extensible and adaptable. I figured that if someone was going to change my code in the future then it should be easy to do. But I never really had a clear idea on how far into the future that should be. So my new boss told me not to bother coding for anything more that 3 years into the future and his reasoning was that technology changes, programs expire etc. At first I was kinda taken aback and thought he was a whack job but the longer I think about it the more I'm warming to the concept. Does anyone else have an opinion on how far into the future you should code to?

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