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  • Key Windows Phone Development Concepts

    - by Tim Murphy
    As I am doing more development in and out of the enterprise arena for Windows Phone I decide I would study for the 70-599 test.  I generally take certification tests as a way to force me to dig deeper into a technology.  Between the development and studying I decided it would be good to put a post together of key development features in Windows Phone 7 environment.  Contrary to popular belief the launch of Windows Phone 8 will not obsolete Windows Phone 7 development.  With the launch of 7.8 coming shortly and people who will remain on 7.X for the foreseeable future there are still consumers needing these apps so don’t throw out the baby with the bath water. PhoneApplicationService This is a class that every Windows Phone developer needs to become familiar with.  When it comes to application state this is your go to repository.  It also contains events that help with management of your application’s lifecycle.  You can access it like the following code sample. 1: PhoneApplicationService.Current.State["ValidUser"] = userResult; DeviceNetworkInformation This class allows you to determine the connectivity of the device and be notified when something changes with that connectivity.  If you are making web service calls you will want to check here before firing off. I have found that this class doesn’t actually work very well for determining if you have internet access.  You are better of using the following code where IsConnectedToInternet is an App level property. private void Application_Launching(object sender, LaunchingEventArgs e){ // Validate user access if (Microsoft.Phone.Net.NetworkInformation.NetworkInterface.NetworkInterfaceType != Microsoft.Phone.Net.NetworkInformation.NetworkInterfaceType.None) { IsConnectedToInternet = true; } else { IsConnectedToInternet = false; } NetworkChange.NetworkAddressChanged += new NetworkAddressChangedEventHandler(NetworkChange_NetworkAddressChanged);}void NetworkChange_NetworkAddressChanged(object sender, EventArgs e){ IsConnectedToInternet = (Microsoft.Phone.Net.NetworkInformation.NetworkInterface.NetworkInterfaceType != Microsoft.Phone.Net.NetworkInformation.NetworkInterfaceType.None);} Push Notification Push notification allows your application to receive notifications in a way that reduces the application’s power needs. This MSDN article is a good place to get the basics of push notification, but you can see the essential concept in the diagram below.  There are three types of push notification: toast, Tile and raw.  The first two work regardless of the state of the application where as raw messages are discarded if your application is not running.   Live Tiles Live tiles are one of the main differentiators of the Windows Phone platform.  They allow users to find information at a glance from their start screen without navigating into individual apps.  Knowing how to implement them can be a great boost to the attractiveness of your application. The simplest step-by-step explanation for creating live tiles is here. Local Database While your application really only has Isolated Storage as a data store there are some ways of giving you database functionality to develop against.  There are a number of open source ORM style solutions.  Probably the best and most native way I have found is to use LINQ to SQL.  It does take a significant amount of setup, but the ease of use once it is configured is worth the cost.  Rather than repeat the full concepts here I will point you to a post that I wrote previously. Tasks (Bing, Email) Leveraging built in features of the Windows Phone platform is an easy way to add functionality that would be expensive to develop on your own.  The classes that you need to make yourself familiar with are BingMapsDirectionsTask and EmailComposeTask.  This will allow your application to supply directions and give the user an email path to relay information to friends and associates. Event model Because of the ability for users to switch quickly to switch to other apps or the home screen is just one reason why knowing the Windows Phone event model is important.  You need to be able to save data so that if a user gets a phone call they can come back to exactly where they were in your application.  This means that you will need to handle such events as Launching, Activated, Deactivated and Closing at an application level.  You will probably also want to get familiar with the OnNavigatedTo and OnNavigatedFrom events at the page level.  These will give you an opportunity to save data as a user navigates through your app. Summary This is just a small portion of the concepts that you will use while building Windows Phone apps, but these are some of the most critical.  With the launch of Windows Phone 8 this list will probably expand.  Take the time to investigate these topics further and try them out in your apps. del.icio.us Tags: Windows Phone 7,Windows Phone,WP7,Software Development,70-599

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  • Building Enterprise Smartphone App &ndash; Part 2: Platforms and Features

    - by Tim Murphy
    This is part 2 in a series of posts based on a talk I gave recently at the Chicago Information Technology Architects Group.  Feel free to leave feedback. In the previous post I discussed what reasons a company might have for creating a smartphone application.  In this installment I will cover some of history and state of the different platforms as well as features that can be leveraged for building enterprise smartphone applications. Platforms Before you start choosing a platform to develop your solutions on it is good to understand how we got here and what features you can leverage. History To my memory we owe all of this to a product called the Apple Newton that came out in 1987. It was the first PDA and back then I was much more of an Apple fan.  I was very impressed with this device even though it never really went anywhere.  The Palm Pilot by US Robotics was the next major advancement in PDA. It had a simple short hand window that allowed for quick stylus entry.. Later, Windows CE came out and started the broadening of the PDA market. After that it was the Palm and CE operating systems that started showing up on cell phones and for some time these were the two dominant operating systems that were distributed with devices from multiple hardware vendors. Current The iPhone was the first smartphone to take away the stylus and give us a multi-touch interface.  It was a revolution in usability and really changed the attractiveness of smartphones for the general public.  This brought us to the beginning of the current state of the market with the concept of an online store that makes it easy for customers to get new features and functionality on demand. With Android, Google made this more than a one horse race.  Not only did they come to compete, their low cost actually made them the leading OS.  Of course what made Android so attractive also is its major fault.  It is so open that it has been a target for malware which leaves consumers exposed.  Fortunately for Google though, most consumers aren’t aware of the threat that they are under. Although Microsoft had put out one of the first smart phone operating systems with CE it had to play catch up and finally came out with the Windows Phone.  They have gone for a market approach between those of iOS and Android.  They support multiple hardware vendors like Google, but they kept a certification process for applications that is similar to Apple.  They also created a user interface that was different enough to give it a clear separation from the other two platforms. The result of all this is hundreds of millions of smartphones being sold monthly across all three platforms giving us a wide range of choices and challenges when it comes to developing solutions. Features So what are the features that make these devices flexible enough be considered for use in the enterprise? The biggest advantage of today's devices is network connectivity.  The ability to access information from multiple sources at a moment’s notice is critical for businesses.  Add to that the ability to communicate over a variety of text, voice and video modes and we have a powerful starting point. Every smartphone has a cameras and they are not just useful for posting to Instagram. We are seeing more applications such as Bing vision that allow us to scan just about any printed code or text to find information.  These capabilities have been made available to developers in the form of standard libraries for reading barcodes of just about an flavor and optical character recognition (OCR) interpretation. Bluetooth give us the ability to communicate with multiple devices. Whether these are headsets, keyboard or printers the wireless communication capabilities are just starting to evolve.  The more these wireless communication protocols grow, the more opportunities we will see to transfer data between users and a variety of devices. Local storage of information that can be called up even when the device cannot reach the network is the other big capability.  This give users the ability to work offline as well and transmit information when connections are restored. These are the tools that we have to work with to build applications that can be leveraged to gain a competitive advantage for companies that implement them. Coming Up In the third installment I will cover key concerns that you face when building enterprise smartphone apps. del.icio.us Tags: smartphones,enterprise smartphone Apps,architecture,iOS,Android,Windows Phone

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  • With Its MySQL Database-as-a-Service CERN Empowers Scientists

    - by Bertrand Matthelié
    The European Organization for Nuclear Research (CERN) is one of the world’s largest and most respected centers for scientific research. Founded in 1954 and located near Geneva on the Franco-Swiss border, CERN was one of Europe’s first joint ventures. Today, it has 20 member states. The organization uses the world’s largest and most complex scientific instruments to study fundamental particles and the origin of the universe. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Cambria","serif"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Cambria","serif"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Challenges Better support the scientists associated with a CERN research program who selected MySQL as their database. Empower users, enabling them to be as self-reliant as possible. Minimize complexity and costs for the CERN IT department to support the growing number of MySQL deployments. Solution Delivered a MySQL Database-as-a-Service offering to the CERN employees and the scientists associated with the organization. Allowed researchers selecting MySQL for their project to get access to a database instance hosted by the CERN IT department, either from the start or once their application has become critical. Implemented the service using Oracle’s server virtualization software, Oracle VM, for increased flexibility and reduced costs. Empowered users with a self-service approach, providing them with tools to manage MySQL themselves while handling backups and other basic database administration tasks for them. Enabled scientists to rely on MySQL with increased reliability, security and manageability while reducing complexity and minimizing costs. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Cambria","serif"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} "The Cloud model has allowed us to deliver a self-service platform to our MySQL users, empowering them while minimizing costs for CERN." Tony Cass, Database Services Group Leader, IT department, CERN.

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  • R12.0 Cash Management Consolidated Patch Collection (CPC) And R12.1 Cash Management Recommended Patch Collection (RPC)

    - by user793553
    If you have Oracle E-Business Suite's Cash Management (CE) application installed, you'll want to be sure to install the latest CPC (Consolidated Patch Collection) if you are using a R12.0 version of the apps, or the latest RPC (Recommended Patch Collection) for the R12.1 version of the apps. These collections give you all the fixes currently available for known issues in the specified versions of the application, including all of the latest Root Cause Analysis Fixes (RCAs)! What is an "RPC" (for R12.1 users)? Since the release of 12.1, a number of recommended patches for Oracle Cash Management have been made available as standalone patches to help address important business process issues. Adoption of these patches was highly recommended at the time, but not always implemented, so to further facilitate adoption of these patches, Oracle consolidated them into product-specific Recommended Patch Collections (RPCs) - a collection of recommended patches. They were created by Oracle Development with the following goals in mind: Stability: To address data integrity issues that have been identified by Oracle Development and Oracle Software Support as having the potential to interfere with the normal completion of important business processes (such as, period close, etc.). Root Cause Fixes (RCAs): To make available root cause fixes for known data integrity issues. Compact: To keep the file footprint as small as possible to help facilitate the install process and minimize testing. Granular: To compile the collection of patches based on functional areas, allowing a customer to apply multiple RPCs at once, or in phases (based on individual needs and goals). Where to start ALL R12 Cash Management users (R12.0 and R12.1 users) should start with the following Note on My Oracle Support (MOS): Doc ID 1367845.1: R12: Cash Management Recommended Patch Collections It's a great place for important implementation information about both sets of critical patch collections! For R12.1x users R12.1 users should also take a look at the documents below for even more information about the RPC for the R12.1.x versions of the Cash Management application, and other related available RPCs: Note Number  Title                                                                                                      1489997.1 Master Troubleshooting Guide for CE: Reconciliation & Clearing [VIDEO] 954704.1 EBS: R12.1 Oracle Financials Recommended Patch Collections (RPCs) 1316506.1 R12: Oracle CE: Upgrading from R11i to R12.1: Latest Recommended Patches Patch Wizard Utility While a patch may contain several hundred files, the impact on your system may actually be minimal. Patches contain hard prerequisites that are intended to make a patch work on a very low code baseline. The Patch Wizard Utility will give you a detailed analysis of the patch’s impact on your instance BEFORE it’s applied, so you’ll know exactly what to expect from the application. Please refer to Doc ID 976188.1 for more information on this important utility

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  • Different fan behaviour in my laptop after upgrade, what to do now?

    - by student
    After upgrading from lubuntu 13.10 to 14.04 the fan of my laptop seems to run much more often than in 13.10. When it runs, it doesn't run continously but starts and stops every second. fwts fan results in Results generated by fwts: Version V14.03.01 (2014-03-27 02:14:17). Some of this work - Copyright (c) 1999 - 2014, Intel Corp. All rights reserved. Some of this work - Copyright (c) 2010 - 2014, Canonical. This test run on 12/05/14 at 21:40:13 on host Linux einstein 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64. Command: "fwts fan". Running tests: fan. fan: Simple fan tests. -------------------------------------------------------------------------------- Test 1 of 2: Test fan status. Test how many fans there are in the system. Check for the current status of the fan(s). PASSED: Test 1, Fan cooling_device0 of type Processor has max cooling state 10 and current cooling state 0. PASSED: Test 1, Fan cooling_device1 of type Processor has max cooling state 10 and current cooling state 0. PASSED: Test 1, Fan cooling_device2 of type LCD has max cooling state 15 and current cooling state 10. Test 2 of 2: Load system, check CPU fan status. Test how many fans there are in the system. Check for the current status of the fan(s). Loading CPUs for 20 seconds to try and get fan speeds to change. Fan cooling_device0 current state did not change from value 0 while CPUs were busy. Fan cooling_device1 current state did not change from value 0 while CPUs were busy. ADVICE: Did not detect any change in the CPU related thermal cooling device states. It could be that the devices are returning static information back to the driver and/or the fan speed is automatically being controlled by firmware using System Management Mode in which case the kernel interfaces being examined may not work anyway. ================================================================================ 3 passed, 0 failed, 0 warning, 0 aborted, 0 skipped, 0 info only. ================================================================================ 3 passed, 0 failed, 0 warning, 0 aborted, 0 skipped, 0 info only. Test Failure Summary ================================================================================ Critical failures: NONE High failures: NONE Medium failures: NONE Low failures: NONE Other failures: NONE Test |Pass |Fail |Abort|Warn |Skip |Info | ---------------+-----+-----+-----+-----+-----+-----+ fan | 3| | | | | | ---------------+-----+-----+-----+-----+-----+-----+ Total: | 3| 0| 0| 0| 0| 0| ---------------+-----+-----+-----+-----+-----+-----+ Here is the output of lsmod lsmod Module Size Used by i8k 14421 0 zram 18478 2 dm_crypt 23177 0 gpio_ich 13476 0 dell_wmi 12761 0 sparse_keymap 13948 1 dell_wmi snd_hda_codec_hdmi 46207 1 snd_hda_codec_idt 54645 1 rfcomm 69160 0 arc4 12608 2 dell_laptop 18168 0 bnep 19624 2 dcdbas 14928 1 dell_laptop bluetooth 395423 10 bnep,rfcomm iwldvm 232285 0 mac80211 626511 1 iwldvm snd_hda_intel 52355 3 snd_hda_codec 192906 3 snd_hda_codec_hdmi,snd_hda_codec_idt,snd_hda_intel snd_hwdep 13602 1 snd_hda_codec snd_pcm 102099 3 snd_hda_codec_hdmi,snd_hda_codec,snd_hda_intel snd_page_alloc 18710 2 snd_pcm,snd_hda_intel snd_seq_midi 13324 0 snd_seq_midi_event 14899 1 snd_seq_midi snd_rawmidi 30144 1 snd_seq_midi coretemp 13435 0 kvm_intel 143060 0 kvm 451511 1 kvm_intel snd_seq 61560 2 snd_seq_midi_event,snd_seq_midi joydev 17381 0 serio_raw 13462 0 iwlwifi 169932 1 iwldvm pcmcia 62299 0 snd_seq_device 14497 3 snd_seq,snd_rawmidi,snd_seq_midi snd_timer 29482 2 snd_pcm,snd_seq lpc_ich 21080 0 cfg80211 484040 3 iwlwifi,mac80211,iwldvm yenta_socket 41027 0 pcmcia_rsrc 18407 1 yenta_socket pcmcia_core 23592 3 pcmcia,pcmcia_rsrc,yenta_socket binfmt_misc 17468 1 snd 69238 17 snd_hwdep,snd_timer,snd_hda_codec_hdmi,snd_hda_codec_idt,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec,snd_hda_intel,snd_seq_device,snd_seq_midi soundcore 12680 1 snd parport_pc 32701 0 mac_hid 13205 0 ppdev 17671 0 lp 17759 0 parport 42348 3 lp,ppdev,parport_pc firewire_ohci 40409 0 psmouse 102222 0 sdhci_pci 23172 0 sdhci 43015 1 sdhci_pci firewire_core 68769 1 firewire_ohci crc_itu_t 12707 1 firewire_core ahci 25819 2 libahci 32168 1 ahci i915 783485 2 wmi 19177 1 dell_wmi i2c_algo_bit 13413 1 i915 drm_kms_helper 52758 1 i915 e1000e 254433 0 drm 302817 3 i915,drm_kms_helper ptp 18933 1 e1000e pps_core 19382 1 ptp video 19476 1 i915 I tried one answer to the similar question: loud fan on Ubuntu 14.04 and created a /etc/i8kmon.conf like the following: # Run as daemon, override with --daemon option set config(daemon) 1 # Automatic fan control, override with --auto option set config(auto) 1 # Status check timeout (seconds), override with --timeout option set config(timeout) 2 # Report status on stdout, override with --verbose option set config(verbose) 1 # Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt} set config(0) {{0 0} -1 55 -1 55} set config(1) {{0 1} 50 60 55 65} set config(2) {{1 1} 55 80 60 85} set config(3) {{2 2} 70 128 75 128} With this setup the fan goes on even if the temperature is below 50 degree celsius (I don't see a pattern). However I get the impression that the CPU got's hotter in average than without this file. What changes from 13.10 to 14.04 may be responsible for this? If this is a bug, for which package I should report the bug?

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  • Plagued by multithreaded bugs

    - by koncurrency
    On my new team that I manage, the majority of our code is platform, TCP socket, and http networking code. All C++. Most of it originated from other developers that have left the team. The current developers on the team are very smart, but mostly junior in terms of experience. Our biggest problem: multi-threaded concurrency bugs. Most of our class libraries are written to be asynchronous by use of some thread pool classes. Methods on the class libraries often enqueue long running taks onto the thread pool from one thread and then the callback methods of that class get invoked on a different thread. As a result, we have a lot of edge case bugs involving incorrect threading assumptions. This results in subtle bugs that go beyond just having critical sections and locks to guard against concurrency issues. What makes these problems even harder is that the attempts to fix are often incorrect. Some mistakes I've observed the team attempting (or within the legacy code itself) includes something like the following: Common mistake #1 - Fixing concurrency issue by just put a lock around the shared data, but forgetting about what happens when methods don't get called in an expected order. Here's a very simple example: void Foo::OnHttpRequestComplete(statuscode status) { m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } So now we have a bug in which Shutdown could get called while OnHttpNetworkRequestComplete is occuring on. A tester finds the bug, captures the crash dump, and assigns the bug to a developer. He in turn fixes the bug like this. void Foo::OnHttpRequestComplete(statuscode status) { AutoLock lock(m_cs); m_pBar->DoSomethingImportant(status); } void Foo::Shutdown() { AutoLock lock(m_cs); m_pBar->Cleanup(); delete m_pBar; m_pBar=nullptr; } The above fix looks good until you realize there's an even more subtle edge case. What happens if Shutdown gets called before OnHttpRequestComplete gets called back? The real world examples my team has are even more complex, and the edge cases are even harder to spot during the code review process. Common Mistake #2 - fixing deadlock issues by blindly exiting the lock, wait for the other thread to finish, then re-enter the lock - but without handling the case that the object just got updated by the other thread! Common Mistake #3 - Even though the objects are reference counted, the shutdown sequence "releases" it's pointer. But forgets to wait for the thread that is still running to release it's instance. As such, components are shutdown cleanly, then spurious or late callbacks are invoked on an object in an state not expecting any more calls. There are other edge cases, but the bottom line is this: Multithreaded programming is just plain hard, even for smart people. As I catch these mistakes, I spend time discussing the errors with each developer on developing a more appropriate fix. But I suspect they are often confused on how to solve each issue because of the enormous amount of legacy code that the "right" fix will involve touching. We're going to be shipping soon, and I'm sure the patches we're applying will hold for the upcoming release. Afterwards, we're going to have some time to improve the code base and refactor where needed. We won't have time to just re-write everything. And the majority of the code isn't all that bad. But I'm looking to refactor code such that threading issues can be avoided altogether. One approach I am considering is this. For each significant platform feature, have a dedicated single thread where all events and network callbacks get marshalled onto. Similar to COM apartment threading in Windows with use of a message loop. Long blocking operations could still get dispatched to a work pool thread, but the completion callback is invoked on on the component's thread. Components could possibly even share the same thread. Then all the class libraries running inside the thread can be written under the assumption of a single threaded world. Before I go down that path, I am also very interested if there are other standard techniques or design patterns for dealing with multithreaded issues. And I have to emphasize - something beyond a book that describes the basics of mutexes and semaphores. What do you think? I am also interested in any other approaches to take towards a refactoring process. Including any of the following: Literature or papers on design patterns around threads. Something beyond an introduction to mutexes and semaphores. We don't need massive parallelism either, just ways to design an object model so as to handle asynchronous events from other threads correctly. Ways to diagram the threading of various components, so that it will be easy to study and evolve solutions for. (That is, a UML equivalent for discussing threads across objects and classes) Educating your development team on the issues with multithreaded code. What would you do?

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  • How to use a nested form for multiple models in one form?

    - by Magicked
    I'm struggling to come up with the proper way to design a form that will allow me to input data for two different models. The form is for an 'Incident', which has the following relationships: belongs_to :customer belongs_to :user has_one :incident_status has_many :incident_notes accepts_nested_attributes_for :incident_notes, :allow_destroy => false So an incident is assigned to a 'Customer' and a 'User', and the user is able to add 'Notes' to the incident. I'm having trouble with the notes part of the form. Here how the form is being submitted: {"commit"=>"Create", "authenticity_token"=>"ECH5Ziv7JAuzs53kt5m/njT9w39UJhfJEs2x0Ms2NA0=", "customer_id"=>"4", "incident"=>{"title"=>"Something bad", "incident_status_id"=>"2", "user_id"=>"2", "other_id"=>"AAA01-042310-001", "incident_note"=>{"note"=>"This is a note"}}} It appears to be attempting to add the incident_note as a field under 'Incident', rather than creating a new entry in the incident_note table with an incident_id foreign key linking back to the incident. Here is the 'IncidentNote' model: belongs_to :incident belongs_to :user Here is the form for 'Incident': <% form_for([@customer,@incident]) do |f| %> <%= f.error_messages %> <p> <%= f.label :other_id, "ID" %><br /> <%= f.text_field :capc_id %> </p> <p> <%= f.label :title %><br /> <%= f.text_field :title %> </p> <p> <%= label_tag 'user', 'Assign to user?' %> <%= f.select :user_id, @users.collect {|u| [u.name, u.id]} %> </p> <p> <%= f.label :incident_status, 'Status?' %> <%= f.select :incident_status_id, @statuses.collect {|s| [s.name, s.id]} %> </p> <p> <% f.fields_for :incident_note do |inote_form| %> <%= inote_form.label :note, 'Add a Note' %> <%= inote_form.text_area :note, :cols => 40, :rows => 20 %> <% end %> </p> <p> <%= f.submit "Create" %> </p> <% end %> And finally, here are the incident_controller entries for New and Create. New: def new @customer = current_user.customer @incident = Incident.new @users = @customer.users @statuses = IncidentStatus.find(:all) @incident_note = IncidentNote.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @incident } end end Create: def create @users = @customer.users @statuses = IncidentStatus.find(:all) @incident = Incident.new(params[:incident]) @incident.customer = @customer @incident_note = @incident.incident_note.build(params[:incident_note]) @incident_note.user = current_user respond_to do |format| if @incident.save flash[:notice] = 'Incident was successfully created.' format.html { redirect_to(@incident) } format.xml { render :xml => @incident, :status => :created, :location => @incident } else format.html { render :action => "new" } format.xml { render :xml => @incident.errors, :status => :unprocessable_entity } end end end I'm not really sure where to look at this point. I'm sure it's just a limitation of my current Rails skill (I don't know much). So if anyone can point me in the right direction I would be very appreciative. Please let me know if more information is needed! Thanks!

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  • WCF Endpoints & Binding Configuration Issues

    - by CodeAbundance
    I am running into a very strange issue here folks. For simplicity I created a project for the sole purpose of testing the issue outside the framework of a larger application and still encountered what is either a bug in WCF within Visual Studio 2010 or something related to my WCF newbie skill set : ) Here is the issue: I have a WCF endpoint I created running inside of an MVC3 project called "SimpleMethod". The method runs inside of a .svc file on the root of the application and it returns a bool. Using the "WCF Service Configuration Editor" I have added the endpoint to my Web.Config along with a called "LargeImageBinding". Here is the service: [OperationContract] public bool SimpleMethod() { return true; } And the Web.Config generated by the Config Tool: <system.serviceModel> <bindings> <wsHttpBinding> <binding name="LargeImageBinding" closeTimeout="00:10:00" /> </wsHttpBinding> </bindings> <services> <service name="WCFEndpoints.ServiceTestOne"> <endpoint address="/ServiceTestOne.svc" binding="wsHttpBinding" bindingConfiguration="LargeImageBinding" contract="WCFEndpoints.IServiceTestOne" /> </service> </services> <behaviors> <serviceBehaviors> <behavior name=""> <serviceMetadata httpGetEnabled="true" /> <serviceDebug includeExceptionDetailInFaults="false" /> </behavior> </serviceBehaviors> </behaviors> <serviceHostingEnvironment multipleSiteBindingsEnabled="true" /> The service renders fine and you can see the endpoint when you navigate to: http://localhost:57364/ServiceTestOne.svc - Now the issue occurs when I create a separate project to consume the service. I add a service reference to a running instance of the above project, point it to: http://localhost:57364/ServiceTestOne.svc Here is the weird part. The service automatically generates just fine but In the Web.Config the endpoint that is generated looks like this: <client> <endpoint address="http://localhost:57364/ServiceTestOne.svc/ServiceTestOne.svc" binding="wsHttpBinding" bindingConfiguration="WSHttpBinding_IServiceTestOne" contract="ServiceTestOne.IServiceTestOne" name="WSHttpBinding_IServiceTestOne"> As you can see it lists the "ServiceTestOne.svc" portion of the address twice! When I make a call to the the service I get the following error: The remote server returned an error: (404) Not Found. I tried removing the extra "/ServiceTestOne.svc" at the end of the endpoint address in the above config, and I get the same exact error. Now what DOES work is if I go back to the WCF application and remove the custom endpoint and binding references in the Web.Config (everything in the "services" and "bindings" tags) then go back to the consumer application, update the reference to the service and make the call to SimpleMethod()....BOOM works like a charm and I get back a bool set to true. The thing is, I need to make custom binding configurations in order to allow for access to the service outside of the defaults, and from what I can tell, any attempt to create custom bindings makes the endpoints seem to run fine, but fail when an actual method call is made. Can anyone see any flaw in how I am putting this together? Thank you for your time - I have been running in circles with this for about a week!

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  • What am I doing wrong?, linking in C++

    - by Facon
    I'm trying to code a simple base64 encoder/decoder (to test my programming skill). I can compile it, but it doesn't link, I've this message error: C:\Documents and Settings\Facon\Escritoriog++ base64.o main.o -o prueba.exe main.o:main.cpp:(.text+0x24a): undefined reference to `Base64Encode(std::vector const&)' collect2: ld returned 1 exit status Compiler & Linker: Mingw32 3.4.5 SO: Windows XP This is my source code: base64.h: #ifndef BASE64_H #define BASE64_H #include <iostream> #include <vector> typedef unsigned char byte; std::string Base64Encode(const std::vector<byte> &array); std::vector<byte> Base64Decode(const std::string &array); #endif base64.cpp: #include "base64.h" std::string Base64Encode(std::vector<byte> &array) { const char *base64_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; const unsigned int size = array.size(); std::string output; for (unsigned int i = 0; (i < size); i++) { if ((size - i) > 3) { output.push_back(static_cast<char>(base64_table[array[i] >> 2])); output.push_back(static_cast<char>(base64_table[((array[i++] & 0x03) << 4) | ((array[i] & 0xF0) >> 4)])); output.push_back(static_cast<char>(base64_table[((array[i++] & 0x0F) << 2) | ((array[i] & 0xC0) >> 4)])); output.push_back(static_cast<char>(base64_table[array[i] & 0x3F])); } else if ((size - i) == 3) { output.push_back(static_cast<char>(base64_table[array[i] >> 2])); output.push_back(static_cast<char>(base64_table[((array[i++] & 0x03) << 4) | ((array[i] & 0xF0) >> 4)])); output.push_back(static_cast<char>(base64_table[(array[i] & 0x0F) << 2])); output.push_back(static_cast<char>('=')); } else if ((size - i) == 2) { output.push_back(static_cast<char>(base64_table[array[i] >> 2])); output.push_back(static_cast<char>(base64_table[(array[i] & 0x03) << 4])); output.push_back('='); output.push_back('='); } } return output; } std::vector<byte> Base64Decode(const std::string &array) // TODO { const char *base64_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; } main.cpp: #include <iostream> #include <vector> #include "base64.h" using namespace std; int main(int argc, char *argv[]) { const char* prueba = "sure."; vector<byte> texto; string codificado; for (unsigned int i = 0; (prueba[i] != 0); i++) { texto.push_back(prueba[i]); } codificado = Base64Encode(texto); cout << codificado; return 0; } PD: Sorry for my bad knowledge of English :P

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  • Very slow compile times on Visual Studio

    - by johnc
    We are getting very slow compile times, which can take upwards of 20+ minutes on dual core 2GHz, 2G Ram machines. A lot of this is due to the size of our solution which has grown to 70+ projects, as well as VSS which is a bottle neck in itself when you have a lot of files. (swapping out VSS is not an option unfortunately, so I don't want this to descend into a VSS bash) We are looking at combing projects (not nice, as we like the separation of concerns, but is a good opportunity to refactor away some dead wood). We are also looking at having multiple solutions to achieve greater separation of concerns and quicker compile times for each element of the application. This I can see will become a dll hell as we try to keep things in synch. I am interested to know how other teams have dealt with this scaling issue, what do you do when your code base reaches a critical mass that you are wasting half the day watching the status bar deliver compile messages UPDATE Apologies, I neglected to mention this is a C# solution. Thanks for all the cpp suggestions, but it's been a few years since I've had to worry about headers. At a distance I say I miss C++, but I'm not sure I want to go back EDIT: Nice suggestions that have helped so far (not saying there aren't other nice suggestions below, just what has helped) New 3GHz laptop - the power of lost utilization works wonders when whinging to management Disable Anti Virus during compile 'Disconnecting' from VSS (actually the network) during compile - I may get us to remove VS-VSS integration altogether and stick to using the VSS UI Still not rip-snorting through a compile, but every bit helps. Orion did mention in a comment that generics may have a play also. From my tests there does appear to be a minimal performance hit, but not high enough to sure - compile times can be inconsistent due to disc activity. Due to time limitations, my tests didn't include as many Generics, or as much code, as would appear in live system, so that may accumulate. I wouldn't avoid using generics where they are supposed to be used, just for compile time performance WORKAROUND We are testing the practice of building new areas of the application in new solutions, importing in the latest dlls as required, them integrating them into the larger solution when we are happy with them. We may also do them same to existing code by creating temporary solutions that just encapsulate the areas we need to work on, and throwing them away after reintegrating the code. We need to weigh up the time it will take to reintegrate this code against the time we gain by not having Rip Van Winkle like experiences with rapid recompiling during development.

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  • Java ReentrantReadWriteLocks - how to safely acquire write lock?

    - by Andrzej Doyle
    I am using in my code at the moment a ReentrantReadWriteLock to synchronize access over a tree-like structure. This structure is large, and read by many threads at once with occasional modifications to small parts of it - so it seems to fit the read-write idiom well. I understand that with this particular class, one cannot elevate a read lock to a write lock, so as per the Javadocs one must release the read lock before obtaining the write lock. I've used this pattern successfully in non-reentrant contexts before. What I'm finding however is that I cannot reliably acquire the write lock without blocking forever. Since the read lock is reentrant and I am actually using it as such, the simple code lock.getReadLock().unlock(); lock.getWriteLock().lock() can block if I have acquired the readlock reentrantly. Each call to unlock just reduces the hold count, and the lock is only actually released when the hold count hits zero. EDIT to clarify this, as I don't think I explained it too well initially - I am aware that there is no built-in lock escalation in this class, and that I have to simply release the read lock and obtain the write lock. My problem is/was that regardless of what other threads are doing, calling getReadLock().unlock() may not actually release this thread's hold on the lock if it acquired it reentrantly, in which case the call to getWriteLock().lock() will block forever as this thread still has a hold on the read lock and thus blocks itself. For example, this code snippet will never reach the println statement, even when run singlethreaded with no other threads accessing the lock: final ReadWriteLock lock = new ReentrantReadWriteLock(); lock.getReadLock().lock(); // In real code we would go call other methods that end up calling back and // thus locking again lock.getReadLock().lock(); // Now we do some stuff and realise we need to write so try to escalate the // lock as per the Javadocs and the above description lock.getReadLock().unlock(); // Does not actually release the lock lock.getWriteLock().lock(); // Blocks as some thread (this one!) holds read lock System.out.println("Will never get here"); So I ask, is there a nice idiom to handle this situation? Specifically, when a thread that holds a read lock (possibly reentrantly) discovers that it needs to do some writing, and thus wants to "suspend" its own read lock in order to pick up the write lock (blocking as required on other threads to release their holds on the read lock), and then "pick up" its hold on the read lock in the same state afterwards? Since this ReadWriteLock implementation was specifically designed to be reentrant, surely there is some sensible way to elevate a read lock to a write lock when the locks may be acquired reentrantly? This is the critical part that means the naive approach does not work.

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  • What is in your Mathematica tool bag?

    - by Timo
    We all know that Mathematica is great, but it also often lacks critical functionality. What kind of external packages / tools / resources do you use with Mathematica? I'll edit (and invite anyone else to do so too) this main post to include resources which are focused on general applicability in scientific research and which as many people as possible will find useful. Feel free to contribute anything, even small code snippets (as I did below for a timing routine). Also, undocumented and useful features in Mathematica 7 and beyond you found yourself, or dug up from some paper/site are most welcome. Please include a short description or comment on why something is great or what utility it provides. If you link to books on Amazon with affiliate links please mention it, e.g., by putting your name after the link. Packages: LevelScheme is a package that greatly expands Mathematica's capability to produce good looking plots. I use it if not for anything else then for the much, much improved control over frame/axes ticks. David Park's Presentation Package ($50 - no charge for updates) Tools: MASH is Daniel Reeves's excellent perl script essentially providing scripting support for Mathematica 7. (This is finally built in as of Mathematica 8 with the -script option.) Resources: Wolfram's own repository MathSource has a lot of useful if narrow notebooks for various applications. Also check out the other sections such as Current Documentation, Courseware for lectures, and Demos for, well, demos. Books: Mathematica programming: an advanced introduction by Leonid Shifrin (web, pdf) is a must read if you want to do anything more than For loops in Mathematica. Quantum Methods with Mathematica by James F. Feagin (amazon) The Mathematica Book by Stephen Wolfram (amazon) (web) Schaum's Outline (amazon) Mathematica in Action by Stan Wagon (amazon) - 600 pages of neat examples and goes up to Mathematica version 7. Visualization techniques are especially good, you can see some of them on the author's Demonstrations Page. Mathematica Programming Fundamentals by Richard Gaylord (pdf) - A good concise introduction to most of what you need to know about Mathematica programming. Undocumented (or scarcely documented) Features: How to customize Mathematica keyboard shortcuts. See this question. How to inspect patterns and functions used by Mathematica's own functions. See this answer How to achieve Consistent size for GraphPlots in Mathematica? See this question.

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  • Using 32bit COM object from C# or VBS on Vista 64bit and getting error 80004005

    - by alexandroid
    I need some mind reading here, since I am trying to do what I do not completely understand. There is a 32-bit application (electronic trading application called CQG) which provides a COM API for external access. I have sample programs and scripts which access this API from Excel, .NET (C++, VB and C#) and shell VBScript. I have these .NET applications as source code and as compiled executables (32-bit, compiled on Windows XP). Now I have Windows Vista Home 64-bit which makes my head to spin. Excel examples work just fine (in Excel 2003). Compiled .NET sample executables work as well. But when I am trying to run .NET C# sample converted to and compiled by Visual Studio C# Expression, or run the VBScript script, I am getting error 80004005 when trying to create an object. Initially the .NET application also gave me 80040154 but then I figured how to make it produce 32-bit code and not 64-bit, so now the errors in C# and VBScript applications are the same. That's all the progress I got for now. And yes, I tried running 32-bit versions of cscript.exe/WScript from SysWOW64 folder on my VBS, but still the result is the same (80004005). How to solve this problem? I am almost ready to believe it is practically impossible, but the fact that Excel VBA works and .NET executables compiled on Windows XP run just fine just makes me angry. There should be a way to beat this thing (some secret which probably only Windows Vista developers know)! I will appreciate any help! PS: I believe code samples do not make much sense here, but this is the line of VBScript which fails: Set CEL = WScript.CreateObject("CQG.CQGCEL.4.0", "CEL_") And this is C#: CQGCEL CEL = new CQGCEL(); Update: Forgot to say UAC is off, of course. And I am working from account with administrator priviledges. I also tried watching which registry keys are read using Process Monitor but everything looks OK for GUIDs of this object. I could not recognize some other GUIDs so I am not sure whether they were critical or not. Is there a chance that this COM object uses Internet Explorer and gets the wrong one (like Internet Explorer 7 instead of Internet Explorer 6 engine or something)?

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  • Why is code quality not popular?

    - by Peter Kofler
    I like my code being in order, i.e. properly formatted, readable, designed, tested, checked for bugs, etc. In fact I am fanatic about it. (Maybe even more than fanatic...) But in my experience actions helping code quality are hardly implemented. (By code quality I mean the quality of the code you produce day to day. The whole topic of software quality with development processes and such is much broader and not the scope of this question.) Code quality does not seem popular. Some examples from my experience include Probably every Java developer knows JUnit, almost all languages implement xUnit frameworks, but in all companies I know, only very few proper unit tests existed (if at all). I know that it's not always possible to write unit tests due to technical limitations or pressing deadlines, but in the cases I saw, unit testing would have been an option. If a developer wanted to write some tests for his/her new code, he/she could do so. My conclusion is that developers do not want to write tests. Static code analysis is often played around in small projects, but not really used to enforce coding conventions or find possible errors in enterprise projects. Usually even compiler warnings like potential null pointer access are ignored. Conference speakers and magazines would talk a lot about EJB3.1, OSGI, Cloud and other new technologies, but hardly about new testing technologies or tools, new static code analysis approaches (e.g. SAT solving), development processes helping to maintain higher quality, how some nasty beast of legacy code was brought under test, ... (I did not attend many conferences and it propably looks different for conferences on agile topics, as unit testing and CI and such has a higer value there.) So why is code quality so unpopular/considered boring? EDIT: Thank your for your answers. Most of them concern unit testing (and has been discussed in a related question). But there are lots of other things that can be used to keep code quality high (see related question). Even if you are not able to use unit tests, you could use a daily build, add some static code analysis to your IDE or development process, try pair programming or enforce reviews of critical code.

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  • Flash Builder missing fundamental things

    - by Bart van Heukelom
    All of a sudden Flash Builder 4 is missing all kinds of fundamental things and is generating incorrect errors. I've had the same issue yesterday, where I fixed it by downloading a new Flex SDK and importing that into FB. I did this again, but this time it fixed nothing. I don't think it's something I did, like removing critical references from the build path. The errors also appeared on projects I was not working on at the time. It occurs for ActionScript, Flex and Flex Library projects alike. Update: I find this stack trace in the Flash Builder error log: !ENTRY com.adobe.flexbuilder.project 4 43 2010-05-11 11:55:47.495 !MESSAGE Uncaught exception in compiler !STACK 0 java.lang.NullPointerException at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2592) at macromedia.asc.parser.VariableBindingNode.evaluate(VariableBindingNode.java:64) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2233) at macromedia.asc.parser.ListNode.evaluate(ListNode.java:44) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2578) at macromedia.asc.parser.VariableDefinitionNode.evaluate(VariableDefinitionNode.java:48) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2310) at macromedia.asc.parser.StatementListNode.evaluate(StatementListNode.java:60) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2503) at macromedia.asc.parser.WithStatementNode.evaluate(WithStatementNode.java:44) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2310) at macromedia.asc.parser.StatementListNode.evaluate(StatementListNode.java:60) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2891) at macromedia.asc.parser.FunctionCommonNode.evaluate(FunctionCommonNode.java:106) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:2905) at macromedia.asc.parser.FunctionCommonNode.evaluate(FunctionCommonNode.java:106) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:3643) at macromedia.asc.parser.ClassDefinitionNode.evaluate(ClassDefinitionNode.java:106) at macromedia.asc.semantics.ConstantEvaluator.evaluate(ConstantEvaluator.java:3371) at macromedia.asc.parser.ProgramNode.evaluate(ProgramNode.java:80) at flex2.compiler.as3.As3Compiler.analyze4(As3Compiler.java:709) at flex2.compiler.CompilerAPI.analyze(CompilerAPI.java:3089) at flex2.compiler.CompilerAPI.analyze(CompilerAPI.java:2977) at flex2.compiler.CompilerAPI.batch2(CompilerAPI.java:528) at flex2.compiler.CompilerAPI.batch(CompilerAPI.java:1274) at flex2.compiler.CompilerAPI.compile(CompilerAPI.java:1496) at flex2.tools.oem.Application.compile(Application.java:1188) at flex2.tools.oem.Application.recompile(Application.java:1133) at flex2.tools.oem.Application.compile(Application.java:819) at flex2.tools.flexbuilder.BuilderApplication.compile(BuilderApplication.java:344) at com.adobe.flexbuilder.multisdk.compiler.internal.ASApplicationBuilder$MyBuilder.mybuild(ASApplicationBuilder.java:276) at com.adobe.flexbuilder.multisdk.compiler.internal.ASApplicationBuilder.build(ASApplicationBuilder.java:127) at com.adobe.flexbuilder.multisdk.compiler.internal.ASBuilder.build(ASBuilder.java:190) at com.adobe.flexbuilder.multisdk.compiler.internal.ASItemBuilder.build(ASItemBuilder.java:74) at com.adobe.flexbuilder.project.compiler.internal.FlexProjectBuilder.buildItem(FlexProjectBuilder.java:480) at com.adobe.flexbuilder.project.compiler.internal.FlexProjectBuilder.build(FlexProjectBuilder.java:306) at com.adobe.flexbuilder.project.compiler.internal.FlexIncrementalBuilder.build(FlexIncrementalBuilder.java:157) at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:627) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:170) at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:201) at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:253) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:256) at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:309) at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:341) at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:140) at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:238) at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

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  • Which OAuth library do you find works best for Objective-C/iPhone?

    - by Brennan
    I have been looking to switch to OAuth for my Twitter integration code and now that there is a deadline in less than 7 weeks (see countdown link) it is even more important to make the jump to OAuth. I have been doing Basic Authentication which is extremely easy. Unfortunately OAuth does not appear to be something that I would whip together in a couple of hours. http://www.countdowntooauth.com/ So I am looking to use a library. I have put together the following list. MPOAuth MGTwitterEngine OAuthConsumer I see that MPOAuth has some great features with a good deal of testing code in place but there is one big problem. It does not work. The sample iPhone project that is supposed to authenticate with Twitter causes an error which others have identified and logged as a bug. http://code.google.com/p/mpoauthconnection/issues/detail?id=29 The last code change was March 11 and this bug was filed on March 30. It has been over a month and this critical bug has not been fixed yet. So I have moved on to MGTwitterEngine. I pulled down the source code and loaded it up in Xcode. Immediately I find that there are a few dependencies and the README file does not have a clear list of steps to fetch those dependencies and integrate them with the project so that it builds successfully. I see this as a sign that the project is not mature enough for prime time. I see also that the project references 2 libraries for JSON when one should be enough. One is TouchJSON which has worked well for me so I am again discouraged from relying on this project for my applications. I did find that MGTwitterEngine makes use of OAuthConsumer which is one of many OAuth projects hosted by an OAuth project on Google Code. http://code.google.com/p/oauth/ http://code.google.com/p/oauthconsumer/wiki/UsingOAuthConsumer It looks like OAuthConsumer is a good choice at first glance. It is hosted with other OAuth libraries and has some nice documentation with it. I pulled down the code and it builds without errors but it does have many warnings. And when I run the new Build and Analyze feature in Xcode 3.2 I see 50 analyzer results. Many are marked as potential memory leaks which would likely lead to instability in any app which uses this library. It seems there is no clear winner and I have to go with something before the big Twitter OAuth deadline. Any suggestions?

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  • XML: Process large data

    - by Atmocreations
    Hello What XML-parser do you recommend for the following purpose: The XML-file (formatted, containing whitespaces) is around 800 MB. It mostly contains three types of tag (let's call them n, w and r). They have an attribute called id which i'd have to search for, as fast as possible. Removing attributes I don't need could save around 30%, maybe a bit more. First part for optimizing the second part: Is there any good tool (command line linux and windows if possible) to easily remove unused attributes in certain tags? I know that XSLT could be used. Or are there any easy alternatives? Also, I could split it into three files, one for each tag to gain speed for later parsing... Speed is not too important for this preparation of the data, of course it would be nice when it took rather minutes than hours. Second part: Once I have the data prepared, be it shortened or not, I should be able to search for the ID-attribute I was mentioning, this being time-critical. Estimations using wc -l tell me that there are around 3M N-tags and around 418K W-tags. The latter ones can contain up to approximately 20 subtags each. W-Tags also contain some, but they would be stripped away. "All I have to do" is navigating between tags containing certain id-attributes. Some tags have references to other id's, therefore giving me a tree, maybe even a graph. The original data is big (as mentioned), but the resultset shouldn't be too big as I only have to pick out certain elements. Now the question: What XML parsing library should I use for this kind of processing? I would use Java 6 in a first instance, with having in mind to be porting it to BlackBerry. Might it be useful to just create a flat file indexing the id's and pointing to an offset in the file? Is it even necessary to do the optimizations mentioned in the upper part? Or are there parser known to be quite as fast with the original data? Little note: To test, I took the id being on the very last line on the file and searching for the id using grep. This took around a minute on a Core 2 Duo. What happens if the file grows even bigger, let's say 5 GB? I appreciate any notice or recommendation. Thank you all very much in advance and regards

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  • Contract developer trying to get outsourcing contract with current client.

    - by Mike
    I work for a major bank as a contract software developer. I've been there a few months, and without exception this place has the worst software practices I've ever seen. The software my team makes has no formal testing, terrible code (not reusable, hard to read, etc), minimal documentation, no defined development process and an absolutely sickening amount of waste due to bureaucratic overhead. Part of my contract is to maintain a group of thousands of very poorly written batch jobs. When one of the jobs fails (read: crashes), it's a developers job to look at the source, figure out what's wrong, fix it, and check it in. There is no quality assurance process or auditing of the results whatsoever. Once the developer says "it works" a manager signs off and it goes into production. What's disturbing is that these jobs essentially grab market data and put it into a third-party risk management system, which provides the bank with critical intelligence. I've discovered the disturbing truth that this has been happening since the 90s and nobody really has evidence the system is getting the correct data! Without going into details, an issue arose on Friday that was so horrible I actually stormed out of the place. I was ready to quit, but I decided to just get out to calm my nerves and possibly go back Monday. I've been reflecting today on how to handle this. I have realized that, in probably less than 6 months, I could (with 2 other developers) remake a large component of this system. The new system would provide them with, as primary benefits, a maintainable codebase less prone to error and a solid QA framework. To do it properly I would have to be outside the bank, the internal bureaucracy is just too much. And moreover, I think a bank is fundamentally not a place that can make good software. This is my plan. Write a report explaining in depth all the problems with their current system Explain why their software practices fail and generate a tremendous amount of error and waste. Use this as the basis for claiming the project must be developed externally. Write a high level development plan, including what resources I will require Hand 1,2,3 to my manager, hopefully he passes it up the chain. Worst case he fires me, but this isn't so bad. Convinced Executive decides to award my company a contract for the new system I have 8 years experience as a software contractor and have delivered my share of successful software products, but all working in-house for small/medium sized companies. When I read this over, I think I have a dynamite plan. But since this is the first time doing something this bold so I have my doubts. My question is, is this a good idea? If you think not, please spare no detail.

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  • Java: error handling with try-catch, empty-try-catch, dummy-return

    - by HH
    A searh uses recursively defined function that easily throws exceptions. I have tried 3 ways to handle exeptions: to ignore with an empty-try-catch() add-dummy-return stop err-propagation due to exeption throw a specific except. (this part I don't really understand. If I throw except, can I force it to continue elsewhere, not continuing the old except-thrown-path?) Some exceptions I do not realy care like during execution removed files -exception (NullPointer) but some I really do like unknown things. Possible exceptions: // 1. if a temp-file or some other file removed during execution -> except. // 2. if no permiss. -> except. // 3. ? --> except. The code is Very import for the whole program. I earlier added clittered-checks, try-catches, avoided-empty-try-catches but it really blurred the logic. Some stoned result here would make the code later much easier to maintain. It was annoying to track random exeptions due to some random temp-file removal! How would you handle exceptions for the critical part? Code public class Find { private Stack<File> fs=new Stack<File>(); private Stack<File> ds=new Stack<File>(); public Stack<File> getD(){ return ds;} public Stack<File> getF(){ return fs;} public Find(String path) { // setting this type of special checks due to errs // propagation makes the code clittered if(path==null) { System.out.println("NULL in Find(path)"); System.exit(9); } this.walk(path); } private void walk( String path ) { File root = new File( path ); File[] list = root.listFiles(); //TODO: dangerous with empty try-catch?! try{ for ( File f : list ) { if ( f.isDirectory() ) { walk( f.getAbsolutePath() ); ds.push(f); } else { fs.push(f); } } }catch(Exception e){e.printStackTrace();} } } Code refactored from here.

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  • In MySQL, what is the most effective query design for joining large tables with many to many relatio

    - by lighthouse65
    In our application, we collect data on automotive engine performance -- basically source data on engine performance based on the engine type, the vehicle running it and the engine design. Currently, the basis for new row inserts is an engine on-off period; we monitor performance variables based on a change in engine state from active to inactive and vice versa. The related engineState table looks like this: +---------+-----------+---------------+---------------------+---------------------+-----------------+ | vehicle | engine | engine_state | state_start_time | state_end_time | engine_variable | +---------+-----------+---------------+---------------------+---------------------+-----------------+ | 080025 | E01 | active | 2008-01-24 16:19:15 | 2008-01-24 16:24:45 | 720 | | 080028 | E02 | inactive | 2008-01-24 16:19:25 | 2008-01-24 16:22:17 | 304 | +---------+-----------+---------------+---------------------+---------------------+-----------------+ For a specific analysis, we would like to analyze table content based on a row granularity of minutes, rather than the current basis of active / inactive engine state. For this, we are thinking of creating a simple productionMinute table with a row for each minute in the period we are analyzing and joining the productionMinute and engineEvent tables on the date-time columns in each table. So if our period of analysis is from 2009-12-01 to 2010-02-28, we would create a new table with 129,600 rows, one for each minute of each day for that three-month period. The first few rows of the productionMinute table: +---------------------+ | production_minute | +---------------------+ | 2009-12-01 00:00 | | 2009-12-01 00:01 | | 2009-12-01 00:02 | | 2009-12-01 00:03 | +---------------------+ The join between the tables would be engineState AS es LEFT JOIN productionMinute AS pm ON es.state_start_time <= pm.production_minute AND pm.production_minute <= es.event_end_time. This join, however, brings up multiple environmental issues: The engineState table has 5 million rows and the productionMinute table has 130,000 rows When an engineState row spans more than one minute (i.e. the difference between es.state_start_time and es.state_end_time is greater than one minute), as is the case in the example above, there are multiple productionMinute table rows that join to a single engineState table row When there is more than one engine in operation during any given minute, also as per the example above, multiple engineState table rows join to a single productionMinute row In testing our logic and using only a small table extract (one day rather than 3 months, for the productionMinute table) the query takes over an hour to generate. In researching this item in order to improve performance so that it would be feasible to query three months of data, our thoughts were to create a temporary table from the engineEvent one, eliminating any table data that is not critical for the analysis, and joining the temporary table to the productionMinute table. We are also planning on experimenting with different joins -- specifically an inner join -- to see if that would improve performance. What is the best query design for joining tables with the many:many relationship between the join predicates as outlined above? What is the best join type (left / right, inner)?

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  • CSS selectors : should I make my CSS easier to read or optimise the speed

    - by Laurent Bourgault-Roy
    As I was working on a small website, I decided to use the PageSpeed extension to check if their was some improvement I could do to make the site load faster. However I was quite surprise when it told me that my use of CSS selector was "inefficient". I was always told that you should keep the usage of the class attribute in the HTML to a minimum, but if I understand correctly what PageSpeed tell me, it's much more efficient for the browser to match directly against a class name. It make sense to me, but it also mean that I need to put more CSS classes in my HTML. It make my .css file harder to read. I usually tend to mark my CSS like this : #mainContent p.productDescription em.priceTag { ... } Which make it easy to read : I know this will affect the main content and that it affect something in a paragraph tag (so I wont start to put all sort of layout code in it) that describe a product and its something that need emphasis. However it seem I should rewrite it as .priceTag { ... } Which remove all context information about the style. And if I want to use differently formatted price tag (for example, one in a list on the sidebar and one in a paragraph), I need to use something like that .paragraphPriceTag { ... } .listPriceTag { ... } Which really annoy me since I seem to duplicate the semantic of the HTML in my classes. And that mean I can't put common style in an unqualified .priceTag { ... } and thus I need to replicate the style in both CSS rule, making it harder to make change. (Altough for that I could use multiple class selector, but IE6 dont support them) I believe making code harder to read for the sake of speed has never been really considered a very good practice . Except where it is critical, of course. This is why people use PHP/Ruby/C# etc. instead of C/assembly to code their site. It's easier to write and debug. So I was wondering if I should stick with few CSS classes and complex selector or if I should go the optimisation route and remove my fancy CSS selectors for the sake of speed? Does PageSpeed make over the top recommandation? On most modern computer, will it even make a difference?

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  • Release Process Improvements

    - by wallismark
    The process of creating a new build and releasing it to production is a critical step in the SDLC but it is often left as an afterthought and varies greatly from one company to the next. I'm hoping people will share improvements they have made to this process in their organisation so we can all takes steps to 'reduce the pain'. So the question is, specify one painful/time consuming part of your release process and what did you do to improve it? My example: at a previous employer all developers made database changes on one common development database. Then when it came to release time, we used Redgate's SQL Compare to generate a huge script from the differences between the Dev and QA databases. This works reasonably well but the problems with this approach are:- ALL changes in the Dev database are included, some of which may still be 'works in progress'. Sometimes developers made conflicting changes (that were not noticed until the release was in production) It was a time consuming and manual process to create and validate the script (by validate I mean, try to weed out issues like problem 1 and 2). When there were problems with the script (eg the order in which things were run such as creating a record which relies on a foreign key record which is in the script but not yet run) it took time to 'tweak' it so it ran smoothly. It's not an ideal scenario for Continuous Integration. So the solution was:- Enforce a policy of all changes to the database must be scripted. A naming convention was important for ensuring the correct running order of the scripts. Create/Use a tool to run the scripts at release time. Developers had their own copy of the database do develop against (so there was no more 'stepping on each others toes') The next release after we started this process was much faster with fewer problems, indeed the only problems found were due to people 'breaking the rules', eg not creating a script. Once the issues with releasing to QA were fixed, when it came time to release to production it was very smooth. We applied a few other changes (like introducing CI) but this was the most significant, overall we reduced release time from around 3 hours down to a max of 10-15 minutes.

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  • Floating point vs integer calculations on modern hardware

    - by maxpenguin
    I am doing some performance critical work in C++, and we are currently using integer calculations for problems that are inherently floating point because "its faster". This causes a whole lot of annoying problems and adds a lot of annoying code. Now, I remember reading about how floating point calculations were so slow approximately circa the 386 days, where I believe (IIRC) that there was an optional co-proccessor. But surely nowadays with exponentially more complex and powerful CPUs it makes no difference in "speed" if doing floating point or integer calculation? Especially since the actual calculation time is tiny compared to something like causing a pipeline stall or fetching something from main memory? I know the correct answer is to benchmark on the target hardware, what would be a good way to test this? I wrote two tiny C++ programs and compared their run time with "time" on Linux, but the actual run time is too variable (doesn't help I am running on a virtual server). Short of spending my entire day running hundreds of benchmarks, making graphs etc. is there something I can do to get a reasonable test of the relative speed? Any ideas or thoughts? Am I completely wrong? The programs I used as follows, they are not identical by any means: #include <iostream> #include <cmath> #include <cstdlib> #include <time.h> int main( int argc, char** argv ) { int accum = 0; srand( time( NULL ) ); for( unsigned int i = 0; i < 100000000; ++i ) { accum += rand( ) % 365; } std::cout << accum << std::endl; return 0; } Program 2: #include <iostream> #include <cmath> #include <cstdlib> #include <time.h> int main( int argc, char** argv ) { float accum = 0; srand( time( NULL ) ); for( unsigned int i = 0; i < 100000000; ++i ) { accum += (float)( rand( ) % 365 ); } std::cout << accum << std::endl; return 0; } Thanks in advance!

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  • Experienced developer trying to get outsourcing contract with current client.

    - by Mike
    I work for a major bank as a contract software developer. I've been there a few months, and without exception this place has the worst software practices I've ever seen. The software my team makes has no formal testing, terrible code (not reusable, hard to read, etc), minimal documentation, no defined development process and an absolutely sickening amount of waste due to bureaucratic overhead. Part of my contract is to maintain a group of thousands of very poorly written batch jobs. When one of the jobs fails (read: crashes), it's a developers job to look at the source, figure out what's wrong, fix it, and check it in. There is no quality assurance process or auditing of the results whatsoever. Once the developer says "it works" a manager signs off and it goes into production. What's disturbing is that these jobs essentially grab market data and put it into a third-party risk management system, which provides the bank with critical intelligence. I've discovered the disturbing truth that this has been happening since the 90s and nobody really has evidence the system is getting the correct data! Without going into details, an issue arose on Friday that was so horrible I actually stormed out of the place. I was ready to quit, but I decided to just get out to calm my nerves and possibly go back Monday. I've been reflecting today on how to handle this. I have realized that, in probably less than 6 months, I could (with 2 other developers) remake a large component of this system. The new system would provide them with, as primary benefits, a maintainable codebase less prone to error and a solid QA framework. To do it properly I would have to be outside the bank, the internal bureaucracy is just too much. And moreover, I think a bank is fundamentally not a place that can make good software. This is my plan. Write a report explaining in depth all the problems with their current system Explain why their software practices fail and generate a tremendous amount of error and waste. Use this as the basis for claiming the project must be developed externally. Write a high level development plan, including what resources I will require Hand 1,2,3 to my manager, hopefully he passes it up the chain. Worst case he fires me, but this isn't so bad. Convinced Executive decides to award my company a contract for the new system I have 8 years experience as a software contractor and have delivered my share of successful software products, but all working in-house for small/medium sized companies. When I read this over, I think I have a dynamite plan. But since this is the first time doing something this bold so I have my doubts. My question is, is this a good idea? If you think not, please spare no detail.

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  • IIS doing unexpected redirect

    - by user2967489
    I have website abc.com and abc.co.in.I have two webservers also. The following issue happens only in abc.co.in with same application deployed on same. We have written a custom IHttpModule and do a rewrite to abc.co.in?some=data. Expected behavior: When user enters some.abc.co.in the expected behavior is browser still display some.abc.co.in but internally call abc.co.in?some=data Actual behavior: The page is rendered properly but in browser the URL changes to some.abc.co.in?some=data I checked what is happening 1.First the server receives the request and does a 301 redirect. 2.The redirect location is some.abc.co.in?some=data I am stuck in this for a day and critical to fix to make our site up and running. How to debug this issue further ?.Any one can think of possible cause? ETW Trace shows <ApplicationData> <TraceData> <DataItem> <OldUrl>/</OldUrl> <NewUrl>/fp?&id=hazzel&params=</NewUrl> </DataItem> </TraceData> </ApplicationData> <ApplicationData> <TraceData> <DataItem> <ModuleName>DefaultDocumentModule</ModuleName> <Notification>128</Notification> <HttpStatus>301</HttpStatus> <HttpReason>Moved Permanently</HttpReason> </DataItem> </TraceData> </ApplicationData> <ApplicationData> <TraceData> <DataItem> <Headers>Content-Type: text/html; charset=UTF-8 Location: http://some.abc.co.in/fp/?id=data Server: Microsoft-IIS/7.5 X-Powered-By: ASP.NET </Headers> </DataItem> </TraceData> </ApplicationData>

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