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  • Better Understand the 'Strategy' Design Pattern

    - by Imran Omar Bukhsh
    Greetings Hope you all are doing great. I have been interested in design patterns for a while and started reading 'Head First Design Patterns'. I started with the first pattern called the 'Strategy' pattern. I went through the problem outlined in the images below and first tried to propose a solution myself so I could really grasp the importance of the pattern. So my question is that why is my solution ( below ) to the problem outlined in the images below not good enough. What are the good / bad points of my solution vs the pattern? What makes the pattern clearly the only viable solution ? Thanks for you input, hope it will help me better understand the pattern. MY SOLUTION Parent Class: DUCK <?php class Duck { public $swimmable; public $quackable; public $flyable; function display() { echo "A Duck Looks Like This<BR/>"; } function quack() { if($this->quackable==1) { echo("Quack<BR/>"); } } function swim() { if($this->swimmable==1) { echo("Swim<BR/>"); } } function fly() { if($this->flyable==1) { echo("Fly<BR/>"); } } } ?> INHERITING CLASS: MallardDuck <?php class MallardDuck extends Duck { function MallardDuck() { $this->quackable = 1; $this->swimmable = 1; } function display() { echo "A Mallard Duck Looks Like This<BR/>"; } } ?> INHERITING CLASS: WoddenDecoyDuck <?php class WoddenDecoyDuck extends Duck { function woddendecoyduck() { $this->quackable = 0; $this->swimmable = 0; } function display() { echo "A Wooden Decoy Duck Looks Like This<BR/>"; } } Thanking you for your input. Imran

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  • Fraud Detection with the SQL Server Suite Part 1

    - by Dejan Sarka
    While working on different fraud detection projects, I developed my own approach to the solution for this problem. In my PASS Summit 2013 session I am introducing this approach. I also wrote a whitepaper on the same topic, which was generously reviewed by my friend Matija Lah. In order to spread this knowledge faster, I am starting a series of blog posts which will at the end make the whole whitepaper. Abstract With the massive usage of credit cards and web applications for banking and payment processing, the number of fraudulent transactions is growing rapidly and on a global scale. Several fraud detection algorithms are available within a variety of different products. In this paper, we focus on using the Microsoft SQL Server suite for this purpose. In addition, we will explain our original approach to solving the problem by introducing a continuous learning procedure. Our preferred type of service is mentoring; it allows us to perform the work and consulting together with transferring the knowledge onto the customer, thus making it possible for a customer to continue to learn independently. This paper is based on practical experience with different projects covering online banking and credit card usage. Introduction A fraud is a criminal or deceptive activity with the intention of achieving financial or some other gain. Fraud can appear in multiple business areas. You can find a detailed overview of the business domains where fraud can take place in Sahin Y., & Duman E. (2011), Detecting Credit Card Fraud by Decision Trees and Support Vector Machines, Proceedings of the International MultiConference of Engineers and Computer Scientists 2011 Vol 1. Hong Kong: IMECS. Dealing with frauds includes fraud prevention and fraud detection. Fraud prevention is a proactive mechanism, which tries to disable frauds by using previous knowledge. Fraud detection is a reactive mechanism with the goal of detecting suspicious behavior when a fraudster surpasses the fraud prevention mechanism. A fraud detection mechanism checks every transaction and assigns a weight in terms of probability between 0 and 1 that represents a score for evaluating whether a transaction is fraudulent or not. A fraud detection mechanism cannot detect frauds with a probability of 100%; therefore, manual transaction checking must also be available. With fraud detection, this manual part can focus on the most suspicious transactions. This way, an unchanged number of supervisors can detect significantly more frauds than could be achieved with traditional methods of selecting which transactions to check, for example with random sampling. There are two principal data mining techniques available both in general data mining as well as in specific fraud detection techniques: supervised or directed and unsupervised or undirected. Supervised techniques or data mining models use previous knowledge. Typically, existing transactions are marked with a flag denoting whether a particular transaction is fraudulent or not. Customers at some point in time do report frauds, and the transactional system should be capable of accepting such a flag. Supervised data mining algorithms try to explain the value of this flag by using different input variables. When the patterns and rules that lead to frauds are learned through the model training process, they can be used for prediction of the fraud flag on new incoming transactions. Unsupervised techniques analyze data without prior knowledge, without the fraud flag; they try to find transactions which do not resemble other transactions, i.e. outliers. In both cases, there should be more frauds in the data set selected for checking by using the data mining knowledge compared to selecting the data set with simpler methods; this is known as the lift of a model. Typically, we compare the lift with random sampling. The supervised methods typically give a much better lift than the unsupervised ones. However, we must use the unsupervised ones when we do not have any previous knowledge. Furthermore, unsupervised methods are useful for controlling whether the supervised models are still efficient. Accuracy of the predictions drops over time. Patterns of credit card usage, for example, change over time. In addition, fraudsters continuously learn as well. Therefore, it is important to check the efficiency of the predictive models with the undirected ones. When the difference between the lift of the supervised models and the lift of the unsupervised models drops, it is time to refine the supervised models. However, the unsupervised models can become obsolete as well. It is also important to measure the overall efficiency of both, supervised and unsupervised models, over time. We can compare the number of predicted frauds with the total number of frauds that include predicted and reported occurrences. For measuring behavior across time, specific analytical databases called data warehouses (DW) and on-line analytical processing (OLAP) systems can be employed. By controlling the supervised models with unsupervised ones and by using an OLAP system or DW reports to control both, a continuous learning infrastructure can be established. There are many difficulties in developing a fraud detection system. As has already been mentioned, fraudsters continuously learn, and the patterns change. The exchange of experiences and ideas can be very limited due to privacy concerns. In addition, both data sets and results might be censored, as the companies generally do not want to publically expose actual fraudulent behaviors. Therefore it can be quite difficult if not impossible to cross-evaluate the models using data from different companies and different business areas. This fact stresses the importance of continuous learning even more. Finally, the number of frauds in the total number of transactions is small, typically much less than 1% of transactions is fraudulent. Some predictive data mining algorithms do not give good results when the target state is represented with a very low frequency. Data preparation techniques like oversampling and undersampling can help overcome the shortcomings of many algorithms. SQL Server suite includes all of the software required to create, deploy any maintain a fraud detection infrastructure. The Database Engine is the relational database management system (RDBMS), which supports all activity needed for data preparation and for data warehouses. SQL Server Analysis Services (SSAS) supports OLAP and data mining (in version 2012, you need to install SSAS in multidimensional and data mining mode; this was the only mode in previous versions of SSAS, while SSAS 2012 also supports the tabular mode, which does not include data mining). Additional products from the suite can be useful as well. SQL Server Integration Services (SSIS) is a tool for developing extract transform–load (ETL) applications. SSIS is typically used for loading a DW, and in addition, it can use SSAS data mining models for building intelligent data flows. SQL Server Reporting Services (SSRS) is useful for presenting the results in a variety of reports. Data Quality Services (DQS) mitigate the occasional data cleansing process by maintaining a knowledge base. Master Data Services is an application that helps companies maintaining a central, authoritative source of their master data, i.e. the most important data to any organization. For an overview of the SQL Server business intelligence (BI) part of the suite that includes Database Engine, SSAS and SSRS, please refer to Veerman E., Lachev T., & Sarka D. (2009). MCTS Self-Paced Training Kit (Exam 70-448): Microsoft® SQL Server® 2008 Business Intelligence Development and Maintenance. MS Press. For an overview of the enterprise information management (EIM) part that includes SSIS, DQS and MDS, please refer to Sarka D., Lah M., & Jerkic G. (2012). Training Kit (Exam 70-463): Implementing a Data Warehouse with Microsoft® SQL Server® 2012. O'Reilly. For details about SSAS data mining, please refer to MacLennan J., Tang Z., & Crivat B. (2009). Data Mining with Microsoft SQL Server 2008. Wiley. SQL Server Data Mining Add-ins for Office, a free download for Office versions 2007, 2010 and 2013, bring the power of data mining to Excel, enabling advanced analytics in Excel. Together with PowerPivot for Excel, which is also freely downloadable and can be used in Excel 2010, is already included in Excel 2013. It brings OLAP functionalities directly into Excel, making it possible for an advanced analyst to build a complete learning infrastructure using a familiar tool. This way, many more people, including employees in subsidiaries, can contribute to the learning process by examining local transactions and quickly identifying new patterns.

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  • DAO/Webservice Consumption in Web Application

    - by Gavin
    I am currently working on converting a "legacy" web-based (Coldfusion) application from single data source (MSSQL database) to multi-tier OOP. In my current system there is a read/write database with all the usual stuff and additional "read-only" databases that are exported daily/hourly from an Enterprise Resource Planning (ERP) system by SSIS jobs with business product/item and manufacturing/SCM planning data. The reason I have the opportunity and need to convert to multi-tier OOP is a newer more modern ERP system is being implemented business wide that will be a complete replacement. This newer ERP system offers several interfaces for third party applications like mine, from direct SQL access to either a dotNet web-service or a SOAP-like web-service. I have found several suitable frameworks I would be happy to use (Coldspring, FW/1) but I am not sure what design patterns apply to my data access object/component and how to manage the connection/session tokens, with this background, my question has the following three parts: Firstly I have concerns with moving from the relative safety of a SSIS job that protects me from downtime and speed of the ERP system to directly connecting with one of the web services which I note seem significantly slower than I expected (simple/small requests often take up to a whole second). Are there any design patterns I can investigate/use to cache/protect my data tier? It is my understanding data access objects (the component that connects directly with the web services and convert them into the data types I can then work with in my Domain Objects) should be singletons (and will act as an Adapter/Facade), am I correct? As part of the data access object I have to setup a connection by username/password (I could set up multiple users and/or connect multiple times with this) which responds with a session token that needs to be provided on every subsequent request. Do I do this once and share it across the whole application, do I setup a new "connection" for every user of my application and keep the token in their session scope (might quickly hit licensing limits), do I set the "connection" up per page request, or is there a design pattern I am missing that can manage multiple "connections" where a requests/access uses the first free "connection"? It is worth noting if the ERP system dies I will need to reset/invalidate all the connections and start from scratch, and depending on which web-service I use might need manually close the "connection/session"

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  • Delete file then run file at startup

    - by Henry Gibson
    I'm running the music player Foobar2000 through Wine at startup. For some reason when I shutdown Ubuntu the Foobar2000 process is ended abnormally in Wine and when it runs next time I get an annoying "start in safe mode?" message. Not a huge problem, but I'd like it fixed. The safe mode message only appears if a file called "running" is present when Foobar2000 starts (if it isn't deleted when closed properly). So by deleting "running" then starting Foobar2000, the message doesn't appear. I thought it would be easy enough to enter this as a startup command, however it doesn't want to work. The command I am using is rm '/home/henry/.wine/drive_c/users/henry/Application Data/foobar2000/running';'/home/henry/.wine/drive_c/Program Files (x86)/foobar2000/foobar2000.exe' which works fine if I just run it from terminal, the file is deleted then foobar2000 runs. Does anyone know why this isn't working at startup? Also, will this run with a terminal visible? How can I make just the gui appear? Thanks

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  • How to associate all file types within Wine with its corresponding native application?

    - by MestreLion
    This is easily done for a single file type, as answered in How to associate a file type within Wine with a native application?, by creating a .reg for the desired filetype. But this is for AVI only. I use some wine apps (uTorrent, Soulseek, Eudora, to name a few) that can launch a wide range of files. Email attachments, for example, can be JPG, DOC, PDF, PPS... its impossible (and not desirable) to track down all possible file types that one may receive in an email or download in a torrent. So I neeed a solution to be more generic and broad. I need the file association to honor whatever native app is currently configured. And I want this to be done for all file types configured in my system. I've already figured out how to make the solution generic. Simply replacing the launched app in .reg for winebrowser, like this: [HKEY_CLASSES_ROOT\.pdf] @="PDFfile" "Content Type"="application/pdf" [HKEY_CLASSES_ROOT\PDFfile\Shell\Open\command] @="C:\\windows\\system32\\winebrowser.exe \"%1\"" Ive tested this and it works correctly. Since winebrowser uses xdg-open as a backend, and converts my windows path to a Unix one, the correct (Linux) app is launched. So I need a "batch" updater to wine's registry, sort of a wine-update-associations script that I can run whenever a new app is installed. Maybe a tool that can: List all Mime Types types in my system that have a default, installed app associated Extract all the needed info (glob, mime type, etc) Generate the .REG file in the above format The tricky part is: i've searched a LOT to find info about how association is done in Ubuntu 10.10 onwards, and documentation is scarce and confusing, to say the least. Freedesktop.org has no complete spec, and even Gnome docs are obsolete. So far I've gathered 4 files that contain association info, but im clueless on which (or why) to use, or how to use them to generate the .reg file: ~/.local/share/applications/mimeapps.list ~/.local/share/applications/miminfo.cache /usr/share/applications/miminfo.cache /etc/gnome/defaults.list Any help, script or explanation would be greatly appreciated! Thanks!

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  • Distinguishing between UI command & domain commands

    - by SonOfPirate
    I am building a WPF client application using the MVVM pattern that provides an interface on top of an existing set of business logic residing in a library which is shared with other applications. The business library followed a domain-driven architecture using CQRS to separate the read and write models (no event sourcing). The combination of technologies and patterns has brought up an interesting conundrum: The MVVM pattern uses the command pattern for handling user-interaction with the view models. .NET provides an ICommand interface which is implemented by most MVVM frameworks, like MVVM Light's RelayCommand and Prism's DelegateCommand. For example, the view model would expose a number of command objects as properties that are bound to the UI and respond when the user performs actions like clicking buttons. Many implementations of the CQRS use the command pattern to isolate and encapsulate individual behaviors. In my business library, we have implemented the write model as command / command-handler pairs. As such, when we want to do some work, such as create a new order, we 'issue' a command (CreateOrderCommand) which is routed to the command-handler responsible for executing the command. This is great, clearly explained in many sources and I am good with it. However, take this scenario: I have a ToolbarViewModel which exposes a CreateNewOrderCommand property. This ICommand object is bound to a button in the UI. When clicked, the UI command creates and issues a new CreateOrderCommand object to the domain which is handled by the CreateOrderCommandHandler. This is difficult to explain to other developers and I am finding myself getting tongue-tied because everything is a command. I'm sure I'm not the first developer to have patterns overlap like this where the naming/terminology also overlap. How have you approached distinguishing your commands used in the UI from those used in the domain? (Edit: I should mention that the business library is UI-agnostic, i.e. no UI technology-specific code exists, or will exists, in this library.)

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  • What are some ways to separate game logic from animations and the draw loop?

    - by TMV
    I have only previously made flash games, using MovieClips and such to separate out my animations from my game logic. Now I am getting into trying my hand at making a game for Android, but the game programming theory around separating these things still confuses me. I come from a background of developing non game web applications so I am versed in more MVC like patterns and am stuck in that mindset as I approach game programming. I want to do things like abstract my game by having, for example, a game board class that contains the data for a grid of tiles with instances of a tile class that each contain properties. I can give my draw loop access to this and have it draw the game board based on the properties of each tile on the game board, but I don't understand where exactly animation should go. As far as I can tell, animation sort of sits between the abstracted game logic (model) and the draw loop (view). With my MVC mindset, it's frustrating trying to decide where animation is actually supposed to go. It would have quite a bit of data associated with it like a model, but seemingly needs to be very closely coupled with the draw loop in order to have things like frame independent animation. How can I break out of this mindset and start thinking about patterns that make more sense for games?

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  • How to implement Restricted access to application features

    - by DroidUser
    I'm currently developing a web application, that provides some 'service' to the user. The user will have to select a 'plan' according to which she/he will be allowed to perform application specific actions but up to a limit defined by the plan. A Plan will also limit access to certain features, which will not be available at all for some plans. As an example : say there are 3 plans, 2 actions throughout the application users in plan-1 can perform action-1 3 times, and they can't perform action-2 at all users in plan-2 can perform action-1 10 times, action-2 5 times users in plan-3 can perform action-1 20 times, action-2 10 times So i'm looking for the best way to get this done, and my main concerns besides implementing it, are the following(in no particular order) maintainability/changeability : the number of plans, and type of features/actions will change in the final product industry standard/best practice : for future readiness!! efficiency : ofcourse, i want fast code!! I have never done anything like this before, so i have no clue about how do i go about implementing these functionalities. Any tips/guides/patterns/resources/examples? I did read a little about ACL, RBAC, are they the patterns that i need to follow? Really any sort of feedback will help.

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  • RuntimeError: maximum recursion depth exceeded while calling a Python object

    - by Bilal Basharat
    this error arises when i try to run the following test case which is written in models.py of my django app named 'administration' : from django.test import Client, TestCase from django.core import mail class ClientTest( TestCase ): fixtures = [ 'testdata.json' ] def test_get_register( self ): response = self.client.get( '/accounts/register/', {} ) self.assertEqual( response.status_code, 200 ) the error arises at this line specifically: response = self.client.get( '/accounts/register/', {} ) my django version is 1.2.1 and python 2.6 and satchmo version is 0.9.2-pre hg-unknown. I code in windows platform(xp sp2). The command to run test case is: python manage.py test administration the complete error log is as follow: site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 121, in by_host site = by_host(host=host[4:], id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 124, in by_host site = by_host(host = 'www.%s' % host, id_only=id_only) File "build\bdist.win32\egg\threaded_multihost\sites.py", line 101, in by_host site = Site.objects.get(domain=host) File "C:\django\django\db\models\manager.py", line 132, in get return self.get_query_set().get(*args, **kwargs) File "C:\django\django\db\models\query.py", line 336, in get num = len(clone) File "C:\django\django\db\models\query.py", line 81, in __len__ self._result_cache = list(self.iterator()) File "C:\django\django\db\models\query.py", line 269, in iterator for row in compiler.results_iter(): File "C:\django\django\db\models\sql\compiler.py", line 672, in results_iter for rows in self.execute_sql(MULTI): File "C:\django\django\db\models\sql\compiler.py", line 717, in execute_sql sql, params = self.as_sql() File "C:\django\django\db\models\sql\compiler.py", line 65, in as_sql where, w_params = self.query.where.as_sql(qn=qn, connection=self.connection) File "C:\django\django\db\models\sql\where.py", line 91, in as_sql sql, params = child.as_sql(qn=qn, connection=connection) File "C:\django\django\db\models\sql\where.py", line 94, in as_sql sql, params = self.make_atom(child, qn, connection) File "C:\django\django\db\models\sql\where.py", line 141, in make_atom lvalue, params = lvalue.process(lookup_type, params_or_value, connection) File "C:\django\django\db\models\sql\where.py", line 312, in process connection=connection, prepared=True) File "C:\django\django\db\models\fields\subclassing.py", line 53, in inner return func(*args, **kwargs) File "C:\django\django\db\models\fields\subclassing.py", line 53, in inner return func(*args, **kwargs) File "C:\django\django\db\models\fields\__init__.py", line 323, in get_db_prep _lookup return [self.get_db_prep_value(value, connection=connection, prepared=prepar ed)] File "C:\django\django\db\models\fields\subclassing.py", line 53, in inner return func(*args, **kwargs) File "C:\django\django\db\models\fields\subclassing.py", line 53, in inner return func(*args, **kwargs) RuntimeError: maximum recursion depth exceeded while calling a Python object ---------------------------------------------------------------------- Ran 7 tests in 48.453s FAILED (errors=1) Destroying test database 'default'...

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  • Program for remove exact duplicate files while caching search results

    - by John Thomas
    We need a Windows 7 program to remove/check the duplicates but our situation is somewhat different than the standard one for which there are enough programs. We have a fairly large static archive (collection) of photos spread on several disks. Let's call them Disk A..M. We have also some disks (let's call them Disk 1..9) which contain some duplicates which are to be found on disks A..M. We want to add to our collection new disks (N, O, P... aso.) which will contain the photos from disks 1..9 but, of course, we don't want to have any photos two (or more) times. Of course, theoretically, the task can be solved with a regular file duplicate remover but the time needed will be very big. Ideally, AFAIS now, the real solution would be a program which will scan the disks A..M, store the file sizes/hashes of the photos in an indexed database/file(s) and will check the new disks (1..9) against this database. However I have hard time to find such a program (if exists). Other things to note: we consider that the Disks A..M (the collection) doesn't have any duplicates on them the file names might be changed we aren't interested in approximated (fuzzy) comparison which can be found in some photo comparing programs. We hunt for exact duplicate files. we aren't afraid of command line. :-) we need to work on Win7/XP we prefer (of course) to be freeware TIA for any suggestions, John Th.

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  • Create and Share a File (Also a mysterious error)

    - by Kirk
    My goal is to create a XML file and then send it through the share Intent. I'm able to create a XML file using this code FileOutputStream outputStream = context.openFileOutput(fileName, Context.MODE_WORLD_READABLE); PrintStream printStream = new PrintStream(outputStream); String xml = this.writeXml(); // get XML here printStream.println(xml); printStream.close(); I'm stuck trying to retrieve a Uri to the output file in order to share it. I first tried to access the file by converting the file to a Uri File outFile = context.getFileStreamPath(fileName); return Uri.fromFile(outFile); This returns file:///data/data/com.my.package/files/myfile.xml but I cannot appear to attach this to an email, upload, etc. If I manually check the file length, it's proper and shows there is a reasonable file size. Next I created a content provider and tried to reference the file and it isn't a valid handle to the file. The ContentProvider doesn't ever seem to be called a any point. Uri uri = Uri.parse("content://" + CachedFileProvider.AUTHORITY + "/" + fileName); return uri; This returns content://com.my.package.provider/myfile.xml but I check the file and it's zero length. How do I access files properly? Do I need to create the file with the content provider? If so, how? Update Here is the code I'm using to share. If I select Gmail, it does show as an attachment but when I send it gives an error Couldn't show attachment and the email that arrives has no attachment. public void onClick(View view) { Log.d(TAG, "onClick " + view.getId()); switch (view.getId()) { case R.id.share_cancel: setResult(RESULT_CANCELED, getIntent()); finish(); break; case R.id.share_share: MyXml xml = new MyXml(); Uri uri; try { uri = xml.writeXmlToFile(getApplicationContext(), "myfile.xml"); //uri is "file:///data/data/com.my.package/files/myfile.xml" Log.d(TAG, "Share URI: " + uri.toString() + " path: " + uri.getPath()); File f = new File(uri.getPath()); Log.d(TAG, "File length: " + f.length()); // shows a valid file size Intent shareIntent = new Intent(); shareIntent.setAction(Intent.ACTION_SEND); shareIntent.putExtra(Intent.EXTRA_STREAM, uri); shareIntent.setType("text/plain"); startActivity(Intent.createChooser(shareIntent, "Share")); } catch (FileNotFoundException e) { e.printStackTrace(); } break; } } I noticed that there is an Exception thrown here from inside createChooser(...), but I can't figure out why it's thrown. E/ActivityThread(572): Activity com.android.internal.app.ChooserActivity has leaked IntentReceiver com.android.internal.app.ResolverActivity$1@4148d658 that was originally registered here. Are you missing a call to unregisterReceiver()? I've researched this error and can't find anything obvious. Both of these links suggest that I need to unregister a receiver. Chooser Activity Leak - Android Why does Intent.createChooser() need a BroadcastReceiver and how to implement? I have a receiver setup, but it's for an AlarmManager that is set elsewhere and doesn't require the app to register / unregister. Code for openFile(...) In case it's needed, here is the content provider I've created. public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { String fileLocation = getContext().getCacheDir() + "/" + uri.getLastPathSegment(); ParcelFileDescriptor pfd = ParcelFileDescriptor.open(new File(fileLocation), ParcelFileDescriptor.MODE_READ_ONLY); return pfd; }

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  • SQL SERVER – Import CSV into Database – Transferring File Content into a Database Table using CSVexpress

    - by pinaldave
    One of the most common data integration tasks I run into is a desire to move data from a file into a database table.  Generally the user is familiar with his data, the structure of the file, and the database table, but is unfamiliar with data integration tools and therefore views this task as something that is difficult.  What these users really need is a point and click approach that minimizes the learning curve for the data integration tool.  This is what CSVexpress (www.CSVexpress.com) is all about!  It is based on expressor Studio, a data integration tool I’ve been reviewing over the last several months. With CSVexpress, moving data between data sources can be as simple as providing the database connection details, describing the structure of the incoming and outgoing data and then connecting two pre-programmed operators.   There’s no need to learn the intricacies of the data integration tool or to write code.  Let’s look at an example. Suppose I have a comma separated value data file with data similar to the following, which is a listing of terminated employees that includes their hiring and termination date, department, job description, and final salary. EMP_ID,STRT_DATE,END_DATE,JOB_ID,DEPT_ID,SALARY 102,13-JAN-93,24-JUL-98 17:00,Programmer,60,"$85,000" 101,21-SEP-89,27-OCT-93 17:00,Account Representative,110,"$65,000" 103,28-OCT-93,15-MAR-97 17:00,Account Manager,110,"$75,000" 304,17-FEB-96,19-DEC-99 17:00,Marketing,20,"$45,000" 333,24-MAR-98,31-DEC-99 17:00,Data Entry Clerk,50,"$35,000" 100,17-SEP-87,17-JUN-93 17:00,Administrative Assistant,90,"$40,000" 334,24-MAR-98,31-DEC-98 17:00,Sales Representative,80,"$40,000" 400,01-JAN-99,31-DEC-99 17:00,Sales Manager,80,"$55,000" Notice the concise format used for the date values, the fact that the termination date includes both date and time information, and that the salary is clearly identified as money by the dollar sign and digit grouping.  In moving this data to a database table I want to express the dates using a format that includes the century since it’s obvious that this listing could include employees who left the company in both the 20th and 21st centuries, and I want the salary to be stored as a decimal value without the currency symbol and grouping character.  Most data integration tools would require coding within a transformation operation to effect these changes, but not expressor Studio.  Directives for these modifications are included in the description of the incoming data. Besides starting the expressor Studio tool and opening a project, the first step is to create connection artifacts, which describe to expressor where data is stored.  For this example, two connection artifacts are required: a file connection, which encapsulates the file system location of my file; and a database connection, which encapsulates the database connection information.  With expressor Studio, I use wizards to create these artifacts. First click New Connection > File Connection in the Home tab of expressor Studio’s ribbon bar, which starts the File Connection wizard.  In the first window, I enter the path to the directory that contains the input file.  Note that the file connection artifact only specifies the file system location, not the name of the file. Then I click Next and enter a meaningful name for this connection artifact; clicking Finish closes the wizard and saves the artifact. To create the Database Connection artifact, I must know the location of, or instance name, of the target database and have the credentials of an account with sufficient privileges to write to the target table.  To use expressor Studio’s features to the fullest, this account should also have the authority to create a table. I click the New Connection > Database Connection in the Home tab of expressor Studio’s ribbon bar, which starts the Database Connection wizard.  expressor Studio includes high-performance drivers for many relational database management systems, so I can simply make a selection from the “Supplied database drivers” drop down control.  If my desired RDBMS isn’t listed, I can optionally use an existing ODBC DSN by selecting the “Existing DSN” radio button. In the following window, I enter the connection details.  With Microsoft SQL Server, I may choose to use Windows Authentication rather than rather than account credentials.  After clicking Next, I enter a meaningful name for this connection artifact and clicking Finish closes the wizard and saves the artifact. Now I create a schema artifact, which describes the structure of the file data.  When expressor reads a file, all data fields are typed as strings.  In some use cases this may be exactly what is needed and there is no need to edit the schema artifact.  But in this example, editing the schema artifact will be used to specify how the data should be transformed; that is, reformat the dates to include century designations, change the employee and job ID’s to integers, and convert the salary to a decimal value. Again a wizard is used to create the schema artifact.  I click New Schema > Delimited Schema in the Home tab of expressor Studio’s ribbon bar, which starts the Database Connection wizard.  In the first window, I click Get Data from File, which then displays a listing of the file connections in the project.  When I click on the file connection I previously created, a browse window opens to this file system location; I then select the file and click Open, which imports 10 lines from the file into the wizard. I now view the file’s content and confirm that the appropriate delimiter characters are selected in the “Field Delimiter” and “Record Delimiter” drop down controls; then I click Next. Since the input file includes a header row, I can easily indicate that fields in the file should be identified through the corresponding header value by clicking “Set All Names from Selected Row. “ Alternatively, I could enter a different identifier into the Field Details > Name text box.  I click Next and enter a meaningful name for this schema artifact; clicking Finish closes the wizard and saves the artifact. Now I open the schema artifact in the schema editor.  When I first view the schema’s content, I note that the types of all attributes in the Semantic Type (the right-hand panel) are strings and that the attribute names are the same as the field names in the data file.  To change an attribute’s name and type, I highlight the attribute and click Edit in the Attributes grouping on the Schema > Edit tab of the editor’s ribbon bar.  This opens the Edit Attribute window; I can change the attribute name and select the desired type from the “Data type” drop down control.  In this example, I change the name of each attribute to the name of the corresponding database table column (EmployeeID, StartingDate, TerminationDate, JobDescription, DepartmentID, and FinalSalary).  Then for the EmployeeID and DepartmentID attributes, I select Integer as the data type, for the StartingDate and TerminationDate attributes, I select Datetime as the data type, and for the FinalSalary attribute, I select the Decimal type. But I can do much more in the schema editor.  For the datetime attributes, I can set a constraint that ensures that the data adheres to some predetermined specifications; a starting date must be later than January 1, 1980 (the date on which the company began operations) and a termination date must be earlier than 11:59 PM on December 31, 1999.  I simply select the appropriate constraint and enter the value (1980-01-01 00:00 as the starting date and 1999-12-31 11:59 as the termination date). As a last step in setting up these datetime conversions, I edit the mapping, describing the format of each datetime type in the source file. I highlight the mapping line for the StartingDate attribute and click Edit Mapping in the Mappings grouping on the Schema > Edit tab of the editor’s ribbon bar.  This opens the Edit Mapping window in which I either enter, or select, a format that describes how the datetime values are represented in the file.  Note the use of Y01 as the syntax for the year.  This syntax is the indicator to expressor Studio to derive the century by setting any year later than 01 to the 20th century and any year before 01 to the 21st century.  As each datetime value is read from the file, the year values are transformed into century and year values. For the TerminationDate attribute, my format also indicates that the datetime value includes hours and minutes. And now to the Salary attribute. I open its mapping and in the Edit Mapping window select the Currency tab and the “Use currency” check box.  This indicates that the file data will include the dollar sign (or in Europe the Pound or Euro sign), which should be removed. And on the Grouping tab, I select the “Use grouping” checkbox and enter 3 into the “Group size” text box, a comma into the “Grouping character” text box, and a decimal point into the “Decimal separator” character text box. These entries allow the string to be properly converted into a decimal value. By making these entries into the schema that describes my input file, I’ve specified how I want the data transformed prior to writing to the database table and completely removed the requirement for coding within the data integration application itself. Assembling the data integration application is simple.  Onto the canvas I drag the Read File and Write Table operators, connecting the output of the Read File operator to the input of the Write Table operator. Next, I select the Read File operator and its Properties panel opens on the right-hand side of expressor Studio.  For each property, I can select an appropriate entry from the corresponding drop down control.  Clicking on the button to the right of the “File name” text box opens the file system location specified in the file connection artifact, allowing me to select the appropriate input file.  I indicate also that the first row in the file, the header row, should be skipped, and that any record that fails one of the datetime constraints should be skipped. I then select the Write Table operator and in its Properties panel specify the database connection, normal for the “Mode,” and the “Truncate” and “Create Missing Table” options.  If my target table does not yet exist, expressor will create the table using the information encapsulated in the schema artifact assigned to the operator. The last task needed to complete the application is to create the schema artifact used by the Write Table operator.  This is extremely easy as another wizard is capable of using the schema artifact assigned to the Read Table operator to create a schema artifact for the Write Table operator.  In the Write Table Properties panel, I click the drop down control to the right of the “Schema” property and select “New Table Schema from Upstream Output…” from the drop down menu. The wizard first displays the table description and in its second screen asks me to select the database connection artifact that specifies the RDBMS in which the target table will exist.  The wizard then connects to the RDBMS and retrieves a list of database schemas from which I make a selection.  The fourth screen gives me the opportunity to fine tune the table’s description.  In this example, I set the width of the JobDescription column to a maximum of 40 characters and select money as the type of the LastSalary column.  I also provide the name for the table. This completes development of the application.  The entire application was created through the use of wizards and the required data transformations specified through simple constraints and specifications rather than through coding.  To develop this application, I only needed a basic understanding of expressor Studio, a level of expertise that can be gained by working through a few introductory tutorials.  expressor Studio is as close to a point and click data integration tool as one could want and I urge you to try this product if you have a need to move data between files or from files to database tables. Check out CSVexpress in more detail.  It offers a few basic video tutorials and a preview of expressor Studio 3.5, which will support the reading and writing of data into Salesforce.com. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Download, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • How do I compare the md5sum of a file with the md5 file (that was available to download with the file)?

    - by user91583
    Images are available for a distro on http://livedistro.org/gnulinux/israel-remix-team-mint-12. I want to use the 32-bit version. I have downloaded the ISO file for the 32-bit version (customdist.iso). I have downloaded the md5 file for the ISO file (customdist.iso.md5). I want to calculate the md5sum of the ISO file and compare it to the md5 file. I can use the md5sum command to display within the terminal the calculated md5 for the ISO file. I have searched the web and can't find a way to compare the calculated md5 for the ISO file with the downloaded md5 file. So far, the closest I have come is the command md5sum -c customdist.iso.md5 from within the folder containing both the files, but this command gives the result: md5sum: customdist.iso.md5: no properly formatted MD5 checksum lines found Any ideas?

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  • Utility or technique for swapping files quickly in Windows

    - by foraidt
    I frequently need to swap one file with another, without overwriting the original. Let's say there are two files, foo_new.dll and foo.dll. I usually rename them the follwing way: foo.dll - foo_old.dll, foo_new.dll - foo.dll, [do something with replaced file], foo.dll - foo_new.dll, foo_old.dll - foo.dll. This is ok for a single file to swap but it becomes tedious when swapping multiple files at once. Is there a Windows (7 and preferrably XP) utility or a technique that simplifies this task and works well when swapping multiple files? I'd prefer to be able to use it from within FreeCommander but Windows Explorer would be ok, too.

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  • Java regex patterns - compile time constants or instance members?

    - by KepaniHaole
    Currently, I have a couple of singleton objects where I'm doing matching on regular expressions, and my Patterns are defined like so: class Foobar { private final Pattern firstPattern = Pattern.compile("some regex"); private final Pattern secondPattern = Pattern.compile("some other regex"); // more Patterns, etc. private Foobar() {} public static Foobar create() { /* singleton stuff */ } } But I was told by someone the other day that this is bad style, and Patterns should always be defined at the class level, and look something like this instead: class Foobar { private static final Pattern FIRST_PATTERN = Pattern.compile("some regex"); private static final Pattern SECOND_PATTERN = Pattern.compile("some other regex"); // more Patterns, etc. private Foobar() {} public static Foobar create() { /* singleton stuff */ } } The lifetime of this particular object isn't that long, and my main reason for using the first approach is because it doesn't make sense to me to hold on to the Patterns once the object gets GC'd. Any suggestions / thoughts?

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  • Patterns for non-layered applications

    - by Paul Stovell
    In Patterns of Enterprise Application Architecture, Martin Fowler writes: This book is thus about how you decompose an enterprise application into layers and how those layers work together. Most nontrivial enterprise applications use a layered architecture of some form, but in some situations other approaches, such as pipes and filters, are valuable. I don't go into those situations, focussing instead on the context of a layered architecture because it's the most widely useful. What patterns exist for building non-layered applications/parts of an application? Take a statistical modelling engine for a financial institution. There might be a layer for data access, but I expect that most of the code would be in a single layer. Would you still expect to see Gang of Four patterns in such a layer? How about a domain model? Would you use OO at all, or would it be purely functional? The quote mentions pipes and filters as alternate models to layers. I can easily imagine a such an engine using pipes as a way to break down the data processing. What other patterns exist? Are there common patterns for areas like task scheduling, results aggregation, or work distribution? What are some alternatives to MapReduce?

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  • elffile: ELF Specific File Identification Utility

    - by user9154181
    Solaris 11 has a new standard user level command, /usr/bin/elffile. elffile is a variant of the file utility that is focused exclusively on linker related files: ELF objects, archives, and runtime linker configuration files. All other files are simply identified as "non-ELF". The primary advantage of elffile over the existing file utility is in the area of archives — elffile examines the archive members and can produce a summary of the contents, or per-member details. The impetus to add elffile to Solaris came from the effort to extend the format of Solaris archives so that they could grow beyond their previous 32-bit file limits. That work introduced a new archive symbol table format. Now that there was more than one possible format, I thought it would be useful if the file utility could identify which format a given archive is using, leading me to extend the file utility: % cc -c ~/hello.c % ar r foo.a hello.o % file foo.a foo.a: current ar archive, 32-bit symbol table % ar r -S foo.a hello.o % file foo.a foo.a: current ar archive, 64-bit symbol table In turn, this caused me to think about all the things that I would like the file utility to be able to tell me about an archive. In particular, I'd like to be able to know what's inside without having to unpack it. The end result of that train of thought was elffile. Much of the discussion in this article is adapted from the PSARC case I filed for elffile in December 2010: PSARC 2010/432 elffile Why file Is No Good For Archives And Yet Should Not Be Fixed The standard /usr/bin/file utility is not very useful when applied to archives. When identifying an archive, a user typically wants to know 2 things: Is this an archive? Presupposing that the archive contains objects, which is by far the most common use for archives, what platform are the objects for? Are they for sparc or x86? 32 or 64-bit? Some confusing combination from varying platforms? The file utility provides a quick answer to question (1), as it identifies all archives as "current ar archive". It does nothing to answer the more interesting question (2). To answer that question, requires a multi-step process: Extract all archive members Use the file utility on the extracted files, examine the output for each file in turn, and compare the results to generate a suitable summary description. Remove the extracted files It should be easier and more efficient to answer such an obvious question. It would be reasonable to extend the file utility to examine archive contents in place and produce a description. However, there are several reasons why I decided not to do so: The correct design for this feature within the file utility would have file examine each archive member in turn, applying its full abilities to each member. This would be elegant, but also represents a rather dramatic redesign and re-implementation of file. Archives nearly always contain nothing but ELF objects for a single platform, so such generality in the file utility would be of little practical benefit. It is best to avoid adding new options to standard utilities for which other implementations of interest exist. In the case of the file utility, one concern is that we might add an option which later appears in the GNU version of file with a different and incompatible meaning. Indeed, there have been discussions about replacing the Solaris file with the GNU version in the past. This may or may not be desirable, and may or may not ever happen. Either way, I don't want to preclude it. Examining archive members is an O(n) operation, and can be relatively slow with large archives. The file utility is supposed to be a very fast operation. I decided that extending file in this way is overkill, and that an investment in the file utility for better archive support would not be worth the cost. A solution that is more narrowly focused on ELF and other linker related files is really all that we need. The necessary code for doing this already exists within libelf. All that is missing is a small user-level wrapper to make that functionality available at the command line. In that vein, I considered adding an option for this to the elfdump utility. I examined elfdump carefully, and even wrote a prototype implementation. The added code is small and simple, but the conceptual fit with the rest of elfdump is poor. The result complicates elfdump syntax and documentation, definite signs that this functionality does not belong there. And so, I added this functionality as a new user level command. The elffile Command The syntax for this new command is elffile [-s basic | detail | summary] filename... Please see the elffile(1) manpage for additional details. To demonstrate how output from elffile looks, I will use the following files: FileDescription configA runtime linker configuration file produced with crle dwarf.oAn ELF object /etc/passwdA text file mixed.aArchive containing a mixture of ELF and non-ELF members mixed_elf.aArchive containing ELF objects for different machines not_elf.aArchive containing no ELF objects same_elf.aArchive containing a collection of ELF objects for the same machine. This is the most common type of archive. The file utility identifies these files as follows: % file config dwarf.o /etc/passwd mixed.a mixed_elf.a not_elf.a same_elf.a config: Runtime Linking Configuration 64-bit MSB SPARCV9 dwarf.o: ELF 64-bit LSB relocatable AMD64 Version 1 /etc/passwd: ascii text mixed.a: current ar archive, 32-bit symbol table mixed_elf.a: current ar archive, 32-bit symbol table not_elf.a: current ar archive same_elf.a: current ar archive, 32-bit symbol table By default, elffile uses its "summary" output style. This output differs from the output from the file utility in 2 significant ways: Files that are not an ELF object, archive, or runtime linker configuration file are identified as "non-ELF", whereas the file utility attempts further identification for such files. When applied to an archive, the elffile output includes a description of the archive's contents, without requiring member extraction or other additional steps. Applying elffile to the above files: % elffile config dwarf.o /etc/passwd mixed.a mixed_elf.a not_elf.a same_elf.a config: Runtime Linking Configuration 64-bit MSB SPARCV9 dwarf.o: ELF 64-bit LSB relocatable AMD64 Version 1 /etc/passwd: non-ELF mixed.a: current ar archive, 32-bit symbol table, mixed ELF and non-ELF content mixed_elf.a: current ar archive, 32-bit symbol table, mixed ELF content not_elf.a: current ar archive, non-ELF content same_elf.a: current ar archive, 32-bit symbol table, ELF 64-bit LSB relocatable AMD64 Version 1 The output for same_elf.a is of particular interest: The vast majority of archives contain only ELF objects for a single platform, and in this case, the default output from elffile answers both of the questions about archives posed at the beginning of this discussion, in a single efficient step. This makes elffile considerably more useful than file, within the realm of linker-related files. elffile can produce output in two other styles, "basic", and "detail". The basic style produces output that is the same as that from 'file', for linker-related files. The detail style produces per-member identification of archive contents. This can be useful when the archive contents are not homogeneous ELF object, and more information is desired than the summary output provides: % elffile -s detail mixed.a mixed.a: current ar archive, 32-bit symbol table mixed.a(dwarf.o): ELF 32-bit LSB relocatable 80386 Version 1 mixed.a(main.c): non-ELF content mixed.a(main.o): ELF 64-bit LSB relocatable AMD64 Version 1 [SSE]

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  • VB.NET 2008, Windows 7 and saving files

    - by James Brauman
    Hello, We have to learn VB.NET for the semester, my experience lies mainly with C# - not that this should make a difference to this particular problem. I've used just about the most simple way to save a file using the .NET framework, but Windows 7 won't let me save the file anywhere (or anywhere that I have found yet). Here is the code I am using to save a text file. Dim dialog As FolderBrowserDialog = New FolderBrowserDialog() Dim saveLocation As String = dialog.SelectedPath ... Build up output string ... Try ' Try to write the file. My.Computer.FileSystem.WriteAllText(saveLocation, output, False) Catch PermissionEx As UnauthorizedAccessException ' We do not have permissions to save in this folder. MessageBox.Show("Do not have permissions to save file to the folder specified. Please try saving somewhere different.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) Catch Ex As Exception ' Catch any exceptions that occured when trying to write the file. MessageBox.Show("Writing the file was not successful.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try The problem is that this using this code throws an UnauthorizedAccessException no matter where I try to save the file. I've tried running the .exe file as administrator, and the IDE as administrator. Is this just Windows 7 being overprotective? And if so, what can I do to solve this problem? The requirements state that I be able to save a file! Thanks.

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  • compressed archive with quick access to individual file

    - by eric.frederich
    I need to come up with a file format for new application I am writing. This file will need to hold a bunch other text files which are mostly text but can be other formats as well. Naturally, a compressed tar file seems to fit the bill. The problem is that I want to be able to retrieve some data from the file very quickly and getting just a particular file from a tar.gz file seems to take longer than it should. I am assumeing that this is because it has to decompress the entire file even though I just want one. When I have just a regular uncompressed tar file I can get that data real quick. Lets say the file I need quickly is called data.dat For example the command... tar -x data.dat -zf myfile.tar.gz ... is what takes a lot longer than I'd like. MP3 files have id3 data and jpeg files have exif data that can be read in quickly without opening the entire file. I would like my data.dat file to be available in a similar way. I was thinking that I could leave it uncompressed and seperate from the rest of the files in myfile.tar.gz I could then create a tar file of data.dat and myfile.tar.gz and then hopefully that data would be able to be retrieved faster because it is at the head of outer tar file and is uncompressed. Does this sound right?... putting a compressed tar inside of a tar file? Basically, my need is to have an archive type of file with quick access to one particular file. Tar does this just fine, but I'd also like to have that data compressed and as soon as I do that, I no longer have quick access. Are there other archive formats that will give me that quick access I need? As a side note, this application will be written in Python. If the solution calls for a re-invention of the wheel with my own binary format I am familiar with C and would have no problem writing the Python module in C. Idealy I'd just use tar, dd, cat, gzip, etc though. Thanks, ~Eric

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