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  • How to create wifihotspot in ubuntu 10.04 LTS

    - by aspdeepak
    I am using ubuntu 10.04 LTS in my lenovo laptop and have a android ICS device. I want to create a wifi-hotspot in ubuntu, which I can later use for connecting android device. I need this setup for capturing the packets from android device and later analysing them using wireshark in my ubuntu. I tried to create a new hotspot using "Create a new wireless Network" wizard from network manager applet, but for some reason the following happens. It breaks the existing internet connection(either the WLAN, or ethernet) Its not visible in the list of available WIFI hotspots in the android device. My Chipset information 00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 07) 00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07) 00:03.0 Communication controller: Intel Corporation Mobile 4 Series Chipset MEI Controller (rev 07) 00:19.0 Ethernet controller: Intel Corporation 82567LF Gigabit Network Connection (rev 03) 00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) 00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) 00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) 00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) 00:1c.1 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 2 (rev 03) 00:1c.3 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 4 (rev 03) 00:1c.4 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 5 (rev 03) 00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) 00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) 00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) 00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) 00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation ICH9M/M-E SATA AHCI Controller (rev 03) 00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03) 03:00.0 Network controller: Intel Corporation PRO/Wireless 5100 AGN [Shiloh] Network Connection 15:00.0 CardBus bridge: Ricoh Co Ltd RL5c476 II (rev ba) 15:00.1 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller (rev 04) 15:00.2 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 21) 15:00.3 System peripheral: Ricoh Co Ltd R5C843 MMC Host Controller (rev ff) 15:00.4 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 11) 15:00.5 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 11) Supported interface modes: * IBSS * managed * monitor

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  • Reminder - Article about SharePoint localization

    - by panjkov
    I already wrote about SharePoint localization – in January I published blog post with links for downloads of Language Interface Packs for SharePoint 2010 for official languages in Bosnia and Herzegovina (BiH). Approximately at same time, I wrote detailed article for web portal www.hardwarebase.net , which is published in April 2012. Title of the article is “Localize your SharePoint servers for BiH languages”, and article explains process of installing SharePoint LIP and using it on Team Site. Full...(read more)

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  • RealTek RTL8188CE WiFi adapter doesn't connect reliably

    - by ken.ganong
    I recently bought a new system76 laptop which came pre-installed with Ubuntu 11.10. I've been having trouble with my wireless connectivity. It seems that my connection with my wireless network keeps going in and out. It is not my network--I have seen the same problem on multiple WiFi networks and at different distances and reported link qualities. OS version: Ubuntu 11.10 oneiric kernel version: 3.0.0-14-generic lspci: lspci -nnk | grep -iA2 net 04:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8188CE 802.11b/g/n WiFi Adapter [10ec:8176] (rev 01) Subsystem: Realtek Semiconductor Co., Ltd. Device [10ec:9196] Kernel driver in use: rtl8192ce -- 05:00.0 Ethernet controller [0200]: JMicron Technology Corp. JMC250 PCI Express Gigabit Ethernet Controller [197b:0250] (rev 05) Subsystem: CLEVO/KAPOK Computer Device [1558:2500] Kernel driver in use: jme iwconfig: iwconfig lo no wireless extensions. eth0 no wireless extensions. wlan0 IEEE 802.11bgn ESSID:"peppermintpatty" Mode:Managed Frequency:2.462 GHz Access Point: 98:FC:11:6C:E0:22 Bit Rate=72.2 Mb/s Tx-Power=20 dBm Retry long limit:7 RTS thr=2347 B Fragment thr:off Power Management:off Link Quality=49/70 Signal level=-61 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:1103 Missed beacon:0 lshw: sudo lshw -class network *-network description: Wireless interface product: RTL8188CE 802.11b/g/n WiFi Adapter vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:04:00.0 logical name: wlan0 version: 01 serial: 00:1c:7b:a1:95:04 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=rtl8192ce driverversion=3.0.0-14-generic firmware=N/A ip=192.168.1.106 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn resources: irq:18 ioport:e000(size=256) memory:f7d00000-f7d03fff *-network description: Ethernet interface product: JMC250 PCI Express Gigabit Ethernet Controller vendor: JMicron Technology Corp. physical id: 0 bus info: pci@0000:05:00.0 logical name: eth0 version: 05 serial: 00:90:f5:c0:42:b3 size: 10Mbit/s capacity: 1Gbit/s width: 32 bits clock: 33MHz capabilities: pm pciexpress msix msi bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=jme driverversion=1.0.8 duplex=half latency=0 link=no multicast=yes port=MII speed=10Mbit/s resources: irq:56 memory:f7c20000-f7c23fff ioport:d100(size=128) ioport:d000(size=256) memory:f7c10000-f7c1ffff memory:f7c00000-f7c0ffff Any help would be appreciated. The last time I've dealt with wireless issues, the most given solution was NDIS wrapper and I seem sorely out-of-date.

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  • Questions re: Eclipse Jobs API

    - by BenCole
    Similar to http://stackoverflow.com/questions/8738160/eclipse-jobs-api-for-a-stand-alone-swing-project This question mentions the Jobs API from the Eclipse IDE: ...The disadvantage of the pre-3.0 approach was that the user had to wait until an operation completed before the UI became responsive again. The UI still provided the user the ability to cancel the currently running operation but no other work could be done until the operation completed. Some operations were performed in the background (resource decoration and JDT file indexing are two such examples) but these operations were restricted in the sense that they could not modify the workspace. If a background operation did try to modify the workspace, the UI thread would be blocked if the user explicitly performed an operation that modified the workspace and, even worse, the user would not be able to cancel the operation. A further complication with concurrency was that the interaction between the independent locking mechanisms of different plug-ins often resulted in deadlock situations. Because of the independent nature of the locks, there was no way for Eclipse to recover from the deadlock, which forced users to kill the application... ...The functionality provided by the workspace locking mechanism can be broken down into the following three aspects: Resource locking to ensure multiple operations did not concurrently modify the same resource Resource change batching to ensure UI stability during an operation Identification of an appropriate time to perform incremental building With the introduction of the Jobs API, these areas have been divided into separate mechanisms and a few additional facilities have been added. The following list summarizes the facilities added. Job class: support for performing operations or other work in the background. ISchedulingRule interface: support for determining which jobs can run concurrently. WorkspaceJob and two IWorkspace#run() methods: support for batching of delta change notifications. Background auto-build: running of incremental build at a time when no other running operations are affecting resources. ILock interface: support for deadlock detection and recovery. Job properties for configuring user feedback for jobs run in the background. The rest of this article provides examples of how to use the above-mentioned facilities... In regards to above API, is this an implementation of a particular design pattern? Which one?

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  • Announcing: General Availability of Demantra 7.3.1.4!

    - by user702295
    Announcing: General Availability of Demantra 7.3.1.4! This new release brings important usability upgrades and key requested customer enhancements. Key features released in Demantra 7.3.1.4: - Improved user interface - Improved mobile support - Embed Demantra-Anywhere in Advanced Planning Command Center - Aggregate work orders for Asset Intensive Planning Additionally: - Demantra 7.3.1.4 is certified with VCP 12.1.3.8 only. Availability via patch 14405087.

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  • networking disabled

    - by Parimal
    hi i have internet working but the network manager applet in the ubuntu 10.10 says that it is disabled and i am not able to enable it however i have previously forced the ip address which i am still getting in ifconfig but in wired section of network connections there is no such interface as eth0 where can i see these settings and how can i enable the etwork manager applet in the title bar thanks in advance

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  • Linux Sysadmin: How To Manage LVMs With a GUI

    - by Aviad
    We’ve talked about how to use LVM before, but what if you wanted to accomplish the same tasks only with a comfortable graphical interface? HowTo Geek dives into how to manage LVM drives with a GUI. Image by marfis. How To Boot Your Android Phone or Tablet Into Safe Mode HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices

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  • Automaticaly add virtual hosts in ubuntu

    - by user208202
    I want to create a simple web interface with username, password and domain. Once the users gives the information, a script will be executed creating the host with the name that the user has given and give permissions to access phpmyadmin, upload a file with filezilla. I use ubuntu, with apache and mysql installed. I found many web based interfaces and tutorials how to manually create virtual hosts but I want an automated self made solution. Can anyone help me? Thanks in advance

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  • Windows Azure Recipe: High Performance Computing

    - by Clint Edmonson
    One of the most attractive ways to use a cloud platform is for parallel processing. Commonly known as high-performance computing (HPC), this approach relies on executing code on many machines at the same time. On Windows Azure, this means running many role instances simultaneously, all working in parallel to solve some problem. Doing this requires some way to schedule applications, which means distributing their work across these instances. To allow this, Windows Azure provides the HPC Scheduler. This service can work with HPC applications built to use the industry-standard Message Passing Interface (MPI). Software that does finite element analysis, such as car crash simulations, is one example of this type of application, and there are many others. The HPC Scheduler can also be used with so-called embarrassingly parallel applications, such as Monte Carlo simulations. Whatever problem is addressed, the value this component provides is the same: It handles the complex problem of scheduling parallel computing work across many Windows Azure worker role instances. Drivers Elastic compute and storage resources Cost avoidance Solution Here’s a sketch of a solution using our Windows Azure HPC SDK: Ingredients Web Role – this hosts a HPC scheduler web portal to allow web based job submission and management. It also exposes an HTTP web service API to allow other tools (including Visual Studio) to post jobs as well. Worker Role – typically multiple worker roles are enlisted, including at least one head node that schedules jobs to be run among the remaining compute nodes. Database – stores state information about the job queue and resource configuration for the solution. Blobs, Tables, Queues, Caching (optional) – many parallel algorithms persist intermediate and/or permanent data as a result of their processing. These fast, highly reliable, parallelizable storage options are all available to all the jobs being processed. Training Here is a link to online Windows Azure training labs where you can learn more about the individual ingredients described above. (Note: The entire Windows Azure Training Kit can also be downloaded for offline use.) Windows Azure HPC Scheduler (3 labs)  The Windows Azure HPC Scheduler includes modules and features that enable you to launch and manage high-performance computing (HPC) applications and other parallel workloads within a Windows Azure service. The scheduler supports parallel computational tasks such as parametric sweeps, Message Passing Interface (MPI) processes, and service-oriented architecture (SOA) requests across your computing resources in Windows Azure. With the Windows Azure HPC Scheduler SDK, developers can create Windows Azure deployments that support scalable, compute-intensive, parallel applications. See my Windows Azure Resource Guide for more guidance on how to get started, including links web portals, training kits, samples, and blogs related to Windows Azure.

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  • Can not connect to wireless on 12.04 with Intel WiFi Link 5100

    - by WiData
    I am having problem in connecting to wifi. I have dual boot (Windows 7 and Ubuntu 12.04) on my Dell Studio 15. I upgraded to 12.04 quite some time ago (at least one month) from 11.10. Everything was working fine till yesterday. Since yesterday I can see the list of available Wifi connection but does not connect to any or if connects (after hours of trying) then disconnects after few minutes. My wifi interface is Intel WiFi Link 5100 AGN. However the problem is on both Windows and Ubuntu. Here are outputs of some commands which may be useful for those interested in helping: ~$ ifconfig eth0 Link encap:Ethernet HWaddr 00:22:19:fa:65:bb UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:17 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:794 errors:0 dropped:0 overruns:0 frame:0 TX packets:794 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:56280 (56.2 KB) TX bytes:56280 (56.2 KB) wlan0 Link encap:Ethernet HWaddr 00:22:fb:d2:fc:ce UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:239 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:53603 (53.6 KB) Here is the output for the command sudo lshw -C network *-network description: Wireless interface product: WiFi Link 5100 vendor: Intel Corporation physical id: 0 bus info: pci@0000:04:00.0 logical name: wlan0 version: 00 serial: 00:22:fb:d2:fc:ce width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-48-generic-pae firmware=8.83.5.1 build 33692 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn resources: irq:47 memory:f8000000-f8001fff My kernel version is kernel version 3.2.0-48-generic-pae I also checked this post which was helpful. But I am not sure if what is the exact problem. Any suggestions will be helpful. Should I be changing the firmware/driver? Currently my /lib/firmware has following iwlwifi files /lib/firmware/iwlwifi-1000-5.ucode /lib/firmware/iwlwifi-5000-5.ucode /lib/firmware/iwlwifi-100-5.ucode /lib/firmware/iwlwifi-5150-2.ucode /lib/firmware/iwlwifi-105-6.ucode /lib/firmware/iwlwifi-6000-4.ucode /lib/firmware/iwlwifi-135-6.ucode /lib/firmware/iwlwifi-6000g2a-5.ucode /lib/firmware/iwlwifi-2000-6.ucode /lib/firmware/iwlwifi-6000g2a-6.ucode /lib/firmware/iwlwifi-2030-6.ucode /lib/firmware/iwlwifi-6000g2b-6.ucode /lib/firmware/iwlwifi-3945-2.ucode /lib/firmware/iwlwifi-6050-5.ucode /lib/firmware/iwlwifi-4965-2.ucode Thanks a lot for the help.

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  • "Well, Swing took a bit of a beating this week..."

    - by Geertjan
    One unique aspect of the NetBeans community presence at JavaOne 2012 was its usage of large panels to highlight and discuss various aspects (e.g., Java EE, JavaFX, etc) of NetBeans IDE usage and tools. For example, here's a pic of one of the panels, taken by Markus Eisele: Above you see me, Sean Comerford from ESPN.com, Gerrick Bivins from Halliburton, Angelo D'Agnano and Ioannis Kostaras from the NATO Programming Center, and Çagatay Çivici from PrimeFaces. (And Tinu Awopetu was also on the panel but not in the picture!) On one of those panels a remark was made which has kind of stuck with me. Henry Arousell, a member of the "NetBeans Platform Discussion Panel", who works on accounting software in Sweden, together with Thomas Boqvist, who was also at JavaOne, said, a bit despondently, I thought, the following words at the start of the demo of his very professional looking accounting software: "Well, Swing took a bit of a beating this week..." That remark comes in the light of several JavaFX sessions held at JavaOne, together with many sessions from the web and mobile worlds making the argument that the browser, tablet, and mobile platforms are the future of all applications everywhere. However, then I had another look at the list of Duke's Choice Award winners: http://www.oracle.com/us/corporate/press/1854931 OK, there are 10 winners of the Duke's Choice Award this year. Three of them (JDuchess, London Java Community, Student Nokia Developer Group) are not awards for software, but for people or groups. So, that leaves seven awards. Three of them (Hadoop, Jelastic, and Parleys) are, in one way or another, some kind of web-oriented solution, though both Hadoop and Jelastic are broader than that, but are service-oriented solutions, relating to cloud technologies. That leaves four others: NATO air defense software, Liquid Robotics software, AgroSense software, and UNHCR Refugee Registration software. All these are, on the software level, Java desktop solutions that, on the UI layer, make use of Java Swing, together with LuciadMaps (NATO), GeoToolkit (AgroSense), and WorldWind (Liquid Robotics). (And, it went even further than that, i.e., this is not passive usage of Swing but active and motivated: Timon Veenstra, during his AgroSense demo, said "There are far more Swing applications out there than we seem to think. Web developers just make more noise." And, during his Liquid Robotics demo, James Gosling said: "Not everything can be done in HTML.") Seems to me that Java Swing was the enabler of more Duke's Choice Award winners this year than any other UI-oriented Java technology. Now, I'm not going to interpret that one way or another, since I've noticed that interpretations of facts tend to validate some underlying agenda. Take any fact anywhere and you can interpret it to prove whatever opinion you're already holding to be true. Therefore, no interpretation from me. Simply stating the fact that Swing, far from taking a beating during JavaOne 2012, was a more significant user interface enabler of Duke's Choice Award winners than any other Java user interface technology. That's not an interpretation, but a fact.

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  • Is there an appropriate coding style for implementing an algorithm during an interview?

    - by GlenPeterson
    I failed an interview question in C years ago about converting hex to decimal by not exploiting the ASCII table if (inputDigitByte > 9) hex = inputDigitByte - 'a'. The rise of Unicode has made this question pretty silly, but the point was that the interviewer valued raw execution speed above readability and error handling. They tell you to review algorithms textbooks to prepare for these interviews, yet these same textbooks tend to favor the implementation with the fewest lines of code, even if it has to rely on magic numbers (like "infinity") and a slower, more memory-intensive implementation (like a linked list instead of an array) to do that. I don't know what is right. Coding an algorithm within the space of an interview has at least 3 constraints: time to code, elegance/readability, and efficiency of execution. What trade-offs are appropriate for interview code? How much do you follow the textbook definition of an algorithm? Is it better to eliminate recursion, unroll loops, and use arrays for efficiency? Or is it better to use recursion and special values like "infinity" or Integer.MAX_VALUE to reduce the number of lines of code needed to write the algorithm? Interface: Make a very self-contained, bullet-proof interface, or sloppy and fast? On the one extreme, the array to be sorted might be a public static variable. On the other extreme, it might need to be passed to each method, allowing methods to be called individually from different threads for different purposes. Is it appropriate to use a linked-list data structure for items that are traversed in one direction vs. using arrays and doubling the size when the array is full? Implementing a singly-linked list during the interview is often much faster to code and easier remember for recursive algorithms like MergeSort. Thread safety - just document that it's unsafe, or say so verbally? How much should the interviewee be looking for opportunities for parallel processing? Is bit shifting appropriate? x / 2 or x >> 1 Polymorphism, type safety, and generics? Comments? Variable and method names: qs(a, p, q, r) vs: quickSort(theArray, minIdx, partIdx, maxIdx) How much should you use existing APIs? Obviously you can't use a java.util.HashMap to implement a hash-table, but what about using a java.util.List to accumulate your sorted results? Are there any guiding principals that would answer these and other questions, or is the guiding principal to ask the interviewer? Or maybe this should be the basis of a discussion while writing the code? If an interviewer can't or won't answer one of these questions, are there any tips for coaxing the information out of them?

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  • What source code organization approach helps improve modularity and API/Implementation separation?

    - by Berin Loritsch
    Few languages are as restrictive as Java with file naming standards and project structure. In that language, the file name must match the public class declared in the file, and the file must live in a directory structure matching the class package. I have mixed feelings about that approach. While I never have to guess where a file lives, there's still a lot of empty directories and artificial constraints. There's several languages that define everything about a class in one file, at least by convention. C#, Python (I think), Ruby, Erlang, etc. The commonality in most these languages is that they are object oriented, although that statement can probably be rebuffed (there is one non-OO language in the list already). Finally, there's quite a few languages mostly in the C family that have a separate header and implementation file. For C I think this makes sense, because it is one of the few ways to separate the API interface from implementations. With C it seems that feature is used to promote modularity. Yet, with C++ the way header and implementation files are split seems rather forced. You don't get the same clean API separation that you do with C, and you are forced to include some private details in the header you would rather keep only in the implementation. There's quite a few languages that have a concept that overlaps with interfaces like Java, C#, Go, etc. Some languages use what feels like a hack to provide the same concept like C# using pure virtual abstract classes. Still others don't really have an interface concept and rely on "duck" typing--for example Ruby. Ruby has modules, but those are more along the lines of mixing in behaviors to a class than they are for defining how to interact with a class. In OO terms, interfaces are a powerful way to provide separation between an API client and an API implementation. So to hurry up and ask the question, from a personal experience point of view: Does separation of header and implementation help you write more modular code, or does it get in the way? (it helps to specify the language you are referring to) Does the strict file name to class name scheme of Java help maintainability, or is it unnecessary structure for structure's sake? What would you propose to promote good API/Implementation separation and project maintenance, how would you prefer to do it?

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  • How do I get wireless working on a Dell Inspiron 510m?

    - by user17449
    Why WiFi don't work in my Dell Inspiron 510m with Ubuntu 10.04? Is that usefull? inspiron@Inspiron:~$ rfkill list all inspiron@Inspiron:~$ sudo lshw -C network [sudo] password for inspiron: *-network:0 DISABLED description: Wireless interface product: PRO/Wireless LAN 2100 3B Mini PCI Adapter vendor: Intel Corporation physical id: 3 bus info: pci@0000:01:03.0 logical name: eth1 version: 04 serial: 00:0c:f1:5b:5d:40 width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ipw2100 driverversion=git-1.2.2 firmware=712.0.3:3:00000001 latency=32 link=no maxlatency=34 mingnt=2 multicast=yes wireless=unassociated resources: irq:5 memory:fcffe000-fcffefff *-network:1 description: Ethernet interface product: 82801DB PRO/100 VE (MOB) Ethernet Controller vendor: Intel Corporation physical id: 8 bus info: pci@0000:01:08.0 logical name: eth0 version: 81 serial: 00:11:43:41:d8:b8 size: 10MB/s capacity: 100MB/s width: 32 bits clock: 33MHz capabilities: pm bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=e100 driverversion=3.5.24-k2-NAPI duplex=half firmware=N/A ip=192.168.0.2 latency=32 link=no maxlatency=56 mingnt=8 multicast=yes port=MII speed=10MB/s resources: irq:11 memory:fcffd000-fcffdfff ioport:ecc0(size=64) inspiron@Inspiron:~$ iwconfig wlan0 wlan0 No such device inspiron@Inspiron:~$ ifconfig -a eth0 Link encap:Ethernet Endereço de HW 00:11:43:41:d8:b8 inet end.: 192.168.0.2 Bcast:192.168.0.255 Masc:255.255.255.0 UP BROADCAST MULTICAST MTU:1500 Métrica:1 pacotes RX:0 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:0 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet Endereço de HW 00:0c:f1:5b:5d:40 BROADCAST MULTICAST MTU:1500 Métrica:1 pacotes RX:0 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:0 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) IRQ:5 Endereço de E/S:0xe000 Memória:fcffe000-fcffefff lo Link encap:Loopback Local inet end.: 127.0.0.1 Masc:255.0.0.0 endereço inet6: ::1/128 Escopo:Máquina UP LOOPBACK RUNNING MTU:16436 Métrica:1 pacotes RX:628 erros:0 descartados:0 excesso:0 quadro:0 Pacotes TX:628 erros:0 descartados:0 excesso:0 portadora:0 colisões:0 txqueuelen:0 RX bytes:50104 (50.1 KB) TX bytes:50104 (50.1 KB) inspiron@Inspiron:~$ nm-tool NetworkManager Tool State: connected - Device: eth1 ----------------------------------------------------------------- Type: 802.11 WiFi Driver: ipw2100 State: unavailable Default: no HW Address: 00:0C:F1:5B:5D:40 Capabilities: Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: e100 State: unmanaged Default: no HW Address: 00:11:43:41:D8:B8 Capabilities: Carrier Detect: yes Speed: 10 Mb/s Wired Properties Carrier: off inspiron@Inspiron:~$

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  • Send raw data to USB parallel port after upgrading to 11.10

    - by zaphod
    I have a laser cutter connected via a generic USB to parallel adapter. The laser cutter speaks HPGL, as it happens, but since this is a laser cutter and not a plotter, I usually want to generate the HPGL myself, since I care about the ordering, speed, and direction of cuts and so on. In previous versions of Ubuntu, I was able to print to the cutter by copying an HPGL file directly to the corresponding USB "lp" device. For example: cp foo.plt /dev/usblp1 Well, I just upgraded to Ubuntu 11.10 oneiric, and I can't find any "lp" devices in /dev anymore. D'oh! What's the preferred way to send raw data to a parallel port in Ubuntu? I've tried System Settings Printing + Add, hoping that I might be able to associate my device with some kind of "raw printer" driver and print to it with a command like lp -d LaserCutter foo.plt But my USB to parallel adapter doesn't seem to show up in the list. What I do see are my HP Color LaserJet, two USB-to-serial adapters, "Enter URI", and "Network Printer". Meanwhile, over in /dev, I do see /dev/ttyUSB0 and /dev/ttyUSB1 devices for the 2 USB-to-serial adapters. I don't see anything obvious corresponding to the HP printer (which was /dev/usblp0 prior to the upgrade), except for generic USB stuff. For example, sudo find /dev | grep lp produces no output. I do seem to be able to print to the HP printer just fine, though. The printer setup GUI gives it a device URI starting with "hp:" which isn't much help for the parallel adapter. The CUPS administrator's guide makes it sound like I might need to feed it a device URI of the form parallel:/dev/SOMETHING, but of course if I had a /dev/SOMETHING I'd probably just go on writing to it directly. Here's what dmesg says after I disconnect and reconnect the device from the USB port: [ 924.722906] usb 1-1.1.4: USB disconnect, device number 7 [ 959.993002] usb 1-1.1.4: new full speed USB device number 8 using ehci_hcd And here's how it shows up in lsusb -v: Bus 001 Device 008: ID 1a86:7584 QinHeng Electronics CH340S Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.10 bDeviceClass 0 (Defined at Interface level) bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 idVendor 0x1a86 QinHeng Electronics idProduct 0x7584 CH340S bcdDevice 2.52 iManufacturer 0 iProduct 2 USB2.0-Print iSerial 0 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 32 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes 0x80 (Bus Powered) MaxPower 96mA Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 bNumEndpoints 2 bInterfaceClass 7 Printer bInterfaceSubClass 1 Printer bInterfaceProtocol 2 Bidirectional iInterface 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x82 EP 2 IN bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Endpoint Descriptor: bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2 Transfer Type Bulk Synch Type None Usage Type Data wMaxPacketSize 0x0020 1x 32 bytes bInterval 0 Device Status: 0x0000 (Bus Powered)

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  • Why I Love Microsoft Development

    - by Brian Lanham
    I've been writing software for a while and recently had an opportunity to broaden my horizons and start developing for iOS. We decided to leverage, as much as possible, our existing skills and use MonoTouch and MonoDevelop by Novell.    For those of you who do not know, Mono is a .NET port originally designed for Linux but adapted for other platforms as well. MonoTouch is a port specifically for building iOS applications using the .NET framework. MonoDroid is a port (in CTP-esque release) for Android.   A MISSING COMPONENT - VISUAL DESIGNER   MonoDevelop lacks one very significant component compared with other tools I am using: NO VISUAL DESIGNER. Instead of using an integrated visual designer, MonoDevelop shells to the Mac OS "Interface Builder".  Since MonoDevelop lets me have a "Visual Studio-esque" feel *and* I get to use C#, AND it's FREE, I am gladly willing to overlook this.  In fact, it's not even a question.  Free?  Sure, I'll take it with no Visual Designer.   In my experiences I've grown from UNIX and DOS to .NET development through many steps. Java/JSP/Servlets; Windows; Web; etc. I've been doing .NET for quite a few years and I guess I just got "comfortable" with the tools.   WHY AM I NOT GETTING IT?   Interface Builder (IB) is amazingly confusing for me. I had the opportunity to speak at the Northern VA Code Camp on 12/11/2010. My presentation was "Getting Started with iOS Development using MonoTouch and C#".    At the visual design part of the presentation, I asked one of the 3 or 4 Mac developers in the room about my confusion with the IB. I don't understand why the "Classes" list includes objects. I don't understand what "File's Owner" is. And, most importantly, WHAT THE HECK IS AN OUTLET AND WHY IS IT NECESSARY?!?!?"   His response to these question (especially Outlets): "They did it wrong."   I'm accustom to a visual designer that creates variables for graphical widgets for me. Not IB. Instead, I have to create "Outlets" manually. I still do not understand why and, the explanation from a seasoned Mac developer is that it's wrong. (He received nods of confirmation from the other Mac devs in the room.)   I LOVE MS DEV   I love development for Microsoft platforms using Microsoft development tools. I love Windows 7. I love Visual Studio 2010. I love SQL Server. Azure, Entity Framework, Active Directory, Office, WCF/WF/WPF, etc. are all designed with integration in mind. They are also all designed with developers in mind.   Steve Ballmer recently ranted "It's the developers!" That's why it is relatively quick to build apps using MS tools. Clearly, MS knows that while we usually enjoy building technology solutions, we are here to make money. And we need tools that accelerate our time to market without compromising the power and quality of our solutions.   So, yeah, I am sucking up I guess. But I love Microsoft Development. Thank you, Microsoft, for providing the plethora of great development tools.    P.S. (but please slow down a bit…I'm having trouble keeping up!)

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  • TypeScript first impressions

    - by Bertrand Le Roy
    Anders published a video of his new project today, which aims at creating a superset of JavaScript, that compiles down to regular current JavaScript. Anders is a tremendously clever guy, and it always shows in his work. There is much to like in the enterprise (good code completion, refactoring and adoption of the module pattern instead of namespaces to name three), but a few things made me rise an eyebrow. First, there is no mention of CoffeeScript or Dart, but he does talk briefly about Script# and GWT. This is probably because the target audience seems to be the same as the audience for the latter two, i.e. developers who are more comfortable with statically-typed languages such as C# and Java than dynamic languages such as JavaScript. I don’t think he’s aiming at JavaScript developers. Classes and interfaces, although well executed, are not especially appealing. Second, as any code generation tool (and this is true of CoffeeScript as well), you’d better like the generated code. I didn’t, unfortunately. The code that I saw is not the code I would have written. What’s more, I didn’t always find the TypeScript code especially more expressive than what it gets compiled to. I also have a few questions. Is it possible to duck-type interfaces? For example, if I have an IPoint2D interface with x and y coordinates, can I pass any object that has x and y into a function that expects IPoint2D or do I need to necessarily create a class that implements that interface, and new up an instance that explicitly declares its contract? The appeal of dynamic languages is the ability to make objects as you go. This needs to be kept intact. More technical: why are generated variables and functions prefixed with _ rather than the $ that the EcmaScript spec recommends for machine-generated variables? In conclusion, while this is a good contribution to the set of ideas around JavaScript evolution, I don’t expect a lot of adoption outside of the devoted Microsoft developers, but maybe some influence on the language itself. But I’m often wrong. I would certainly not use it because I disagree with the central motivation for doing this: Anders explicitly says he built this because “writing application-scale JavaScript is hard”. I would restate that “writing application-scale JavaScript is hard for people who are used to statically-typed languages”. The community has built a set of good practices over the last few years that do scale quite well, and many people are successfully developing and maintaining impressive applications directly in JavaScript. You can play with TypeScript here: http://www.typescriptlang.org

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  • Display Driver Issue on an hp TX2-1160ea Notebook

    - by Sam
    I'm new to Linux and recently switched to Ubuntu 11.04 due to my project requirement. My laptop has been freezing and going to black screen of death when I run anything related to display (Share desktop, stream video, etc). Today I went through the Ubuntu forum to install the appropriate graphic driver and, after doing it, I rebooted my PC. It gave an error before login saying "select the recovery mode" and after clicking OK, it didn't give the same error on reboot but I've lost the 11.04 graphical interface and all I see is the interface of Ubuntu v10 with slow visuals (even scrolling up/down on browser is really slow). For the reference, here's a desktop screenshot so that you can understand the situation. Also the laptop is overheating. How can I fix this problem? How can i get the Ubuntu 11.04 view back? I also tried Google, but couldn't find any issue like this. Some general Information: Laptop: HP TouchSmart TX2-1160ea Processor: AMD Turion TX2 Memory: 4GB OS: Ubuntu 11.04 Some debugging information:: $ report-hw | grep controller lspci -knn: 00:11.0 SATA controller [0106]: ATI Technologies Inc SB7x0/SB8x0/SB9x0 SATA Controller [AHCI mode] [1002:4391] lspci -knn: 00:14.3 ISA bridge [0601]: ATI Technologies Inc SB7x0/SB8x0/SB9x0 LPC host controller [1002:439d] lspci -knn: 01:05.0 VGA compatible controller [0300]: ATI Technologies Inc RS780M/RS780MN [Radeon HD 3200 Graphics] [1002:9612] lspci -knn: 08:00.0 Network controller [0280]: Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b] (rev 01) lspci -knn: 09:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller [10ec:8168] (rev 02) And: $ dpkg -l '*fglrx*' Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Description +++-==============-==============-============================================ ii fglrx 2:8.840-0ubunt Video driver for the ATI graphics accelerato ii fglrx-amdcccle 2:8.840-0ubunt Catalyst Control Center for the ATI graphics un fglrx-control <none> (no description available) un fglrx-control- <none> (no description available) ii fglrx-dev 2:8.840-0ubunt Video driver for the ATI graphics accelerato un fglrx-driver <none> (no description available) un fglrx-driver-d <none> (no description available) un fglrx-kernel-s <none> (no description available) un fglrx-modalias <none> (no description available) un xfree86-driver <none> (no description available) un xfree86-driver <none> (no description available) un xorg-driver-fg <none> (no description available) un xorg-driver-fg <none> (no description available) If you need any more information that could help, just ask.

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  • Thread travailleur avec Qt en utilisant les signaux et les slots, un article de Christophe Dumez traduit par Thibaut Cuvelier

    Qt fournit des classes de threads indépendantes de la plateforme, une manière thread-safe de poster des événements et des connexions entre signaux et slots entre les threads. La programmation multithreadée s'avantage des machines à plusieurs processeurs et est aussi utile pour effectuer les opérations chronophages sans geler l'interface utilisateur d'une application. Sans multithreading, tout est fait dans le thread principal.

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  • Building an Infrastructure Cloud with Oracle VM for x86 + Enterprise Manager 12c

    - by Richard Rotter
    Cloud Computing? Everyone is talking about Cloud these days. Everyone is explaining how the cloud will help you to bring your service up and running very fast, secure and with little effort. You can find these kinds of presentations at almost every event around the globe. But what is really behind all this stuff? Is it really so simple? And the answer is: Yes it is! With the Oracle SW Stack it is! In this post, I will try to bring this down to earth, demonstrating how easy it could be to build a cloud infrastructure with Oracle's solution for cloud computing.But let me cover some basics first: How fast can you build a cloud?How elastic is your cloud so you can provide new services on demand? How much effort does it take to monitor and operate your Cloud Infrastructure in order to meet your SLAs?How easy is it to chargeback for your services provided? These are the critical success factors of Cloud Computing. And Oracle has an answer to all those questions. By using Oracle VM for X86 in combination with Enterprise Manager 12c you can build and control your cloud environment very fast and easy. What are the fundamental building blocks for your cloud? Oracle Cloud Building Blocks #1 Hardware Surprise, surprise. Even the cloud needs to run somewhere, hence you will need hardware. This HW normally consists of servers, storage and networking. But Oracles goes beyond that. There are Optimized Solutions available for your cloud infrastructure. This is a cookbook to build your HW cloud platform. For example, building your cloud infrastructure with blades and our network infrastructure will reduce complexity in your datacenter (Blades with switch network modules, splitter cables to reduce the amount of cables, TOR (Top Of the Rack) switches which are building the interface to your infrastructure environment. Reducing complexity even in the cabling will help you to manage your environment more efficient and with less risk. Of course, our engineered systems fit into the cloud perfectly too. Although they are considered as a PaaS themselves, having the database SW (for Exadata) and the application development environment (for Exalogic) already deployed on them, in general they are ideal systems to enable you building your own cloud and PaaS infrastructure. #2 Virtualization The next missing link in the cloud setup is virtualization. For me personally, it's one of the most hidden "secret", that oracle can provide you with a complete virtualization stack in terms of a hypervisor on both architectures: X86 and Sparc CPUs. There is Oracle VM for X86 and Oracle VM for Sparc available at no additional  license costs if your are running this virtualization stack on top of Oracle HW (and with Oracle Premier Support for HW). This completes the virtualization portfolio together with Solaris Zones introduced already with Solaris 10 a few years ago. Let me explain how Oracle VM for X86 works: Oracle VM for x86 consists of two main parts: - The Oracle VM Server: Oracle VM Server is installed on bare metal and it is the hypervisor which is able to run virtual machines. It has a very small footprint. The ISO-Image of Oracle VM Server is only 200MB large. It is very small but efficient. You can install a OVM-Server in less than 5 mins by booting the Server with the ISO-Image assigned and providing the necessary configuration parameters (like installing an Linux distribution). After the installation, the OVM-Server is ready to use. That's all. - The Oracle VM-Manager: OVM-Manager is the central management tool where you can control your OVM-Servers. OVM-Manager provides the graphical user interface, which is an Application Development Framework (ADF) application, with a familiar web-browser based interface, to manage Oracle VM Servers, virtual machines, and resources. The Oracle VM Manager has the following capabilities: Create virtual machines Create server pools Power on and off virtual machines Manage networks and storage Import virtual machines, ISO files, and templates Manage high availability of Oracle VM Servers, server pools, and virtual machines Perform live migration of virtual machines I want to highlight one of the goodies which you can use if you are running Oracle VM for X86: Preconfigured, downloadable Virtual Machine Templates form edelivery With these templates, you can download completely preconfigured Virtual Machines in your environment, boot them up, configure them at first time boot and use it. There are templates for almost all Oracle SW and Applications (like Fusion Middleware, Database, Siebel, etc.) available. #3) Cloud Management The management of your cloud infrastructure is key. This is a day-to-day job. Acquiring HW, installing a virtualization layer on top of it is done just at the beginning and if you want to expand your infrastructure. But managing your cloud, keeping it up and running, deploying new services, changing your chargeback model, etc, these are the daily jobs. These jobs must be simple, secure and easy to manage. The Enterprise Manager 12c Cloud provides this functionality from one management cockpit. Enterprise Manager 12c uses Oracle VM Manager to control OVM Serverpools. Once you registered your OVM-Managers in Enterprise Manager, then you are able to setup your cloud infrastructure and manage everything from Enterprise Manager. What you need to do in EM12c is: ">Register your OVM Manager in Enterprise ManagerAfter Registering your OVM Manager, all the functionality of Oracle VM for X86 is also available in Enterprise Manager. Enterprise Manager works as a "Manger" of the Manager. You can register as many OVM-Managers you want and control your complete virtualization environment Create Roles and Users for your Self Service Portal in Enterprise ManagerWith this step you allow users to logon on the Enterprise Manager Self Service Portal. Users can request Virtual Machines in this portal. Setup the Cloud InfrastructureSetup the Quotas for your self service users. How many VMs can they request? How much of your resources ( cpu, memory, storage, network, etc. etc.)? Which SW components (templates, assemblys) can your self service users request? In this step, you basically set up the complete cloud infrastructure. Setup ChargebackOnce your cloud is set up, you need to configure your chargeback mechanism. The Enterprise Manager collects the resources metrics, which are used in a very deep level. Almost all collected Metrics could be used in the chargeback module. You can define chargeback plans based on configurations (charge for the amount of cpu, memory, storage is assigned to a machine, or for a specific OS which is installed) or chargeback on resource consumption (% of cpu used, storage used, etc). Or you can also define a combination of configuration and consumption chargeback plans. The chargeback module is very flexible. Here is a overview of the workflow how to handle infrastructure cloud in EM: Summary As you can see, setting up an Infrastructure Cloud Service with Oracle VM for X86 and Enterprise Manager 12c is really simple. I personally configured a complete cloud environment with three X86 servers and a small JBOD san box in less than 3 hours. There is no magic in it, it is all straightforward. Of course, you have to have some experience with Oracle VM and Enterprise Manager. Experience in setting up Linux environments helps as well. I plan to publish a technical cookbook in the next few weeks. I hope you found this post useful and will see you again here on our blog. Any hints, comments are welcome!

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  • Suggestions for connecting .NET WPF GUI with Java SE Server

    - by Sam Goldberg
    BACKGROUND We are building a Java (SE) trading application which will be monitoring market data and sending trade messages based on the market data, and also on user defined configuration parameters. We are planning to provide the user with a thin client, built in .NET (WPF) for managing the parameters, controlling the server behavior, and viewing the current state of the trading. The client doesn't need real-time updates; it will instead update the view once every few seconds (or whatever interval is configured by the user). The client has about 6 different operations it needs to perform with the server, for example: CRUD with configuration parameters query subset of the data receive updates of current positions from server It is possible that most of the different operations (except for receiving data) are just different flavors of managing the configuration parameters, but it's too early in our analysis for us to be sure. To connect the client with the server, we have been considering using: SOAP Web Service RESTful service building a custom TCP/IP based API (text or xml) (least preferred - but we use this approach with other applications we have) As best as I understand, pros and cons of the different web service flavors are: SOAP pro: totally automated in .NET (and Java), modifying server side interface require no code changes in communication layer, just running refresh on Web Service reference to regenerate the classes. con: more overhead in the communication layer sending more text, etc. We're not using J2EE container so maybe doesn't work so well with J2SE REST pro: lighter weight, less data. Has good .NET and Java support. (I don't have any real experience with this, so don't know what other benefits it has.) con: client will not be automatically aware if there are any new operations or properties added (?), so communication layer needs to be updated by developer if server interface changes. con: (both approaches) Server cannot really push updates to the client at regular intervals (?) (However, we won't mind if client polls the server to get updates.) QUESTION What are your opinions on the above options or suggestions for other ways to connect the 2 parts? (Ideally, we don't want to put much work into the communication layer, because it's not the significant part of the application so the more off-the-shelf and automated the better.)

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  • Is throwing an error in unpredictable subclass-specific circumstances a violation of LSP?

    - by Motti Strom
    Say, I wanted to create a Java List<String> (see spec) implementation that uses a complex subsystem, such as a database or file system, for its store so that it becomes a simple persistent collection rather than an basic in-memory one. (We're limiting it specifically to a List of Strings for the purposes of discussion, but it could extended to automatically de-/serialise any object, with some help. We can also provide persistent Sets, Maps and so on in this way too.) So here's a skeleton implementation: class DbBackedList implements List<String> { private DbBackedList() {} /** Returns a list, possibly non-empty */ public static getList() { return new DbBackedList(); } public String get(int index) { return Db.getTable().getRow(i).asString(); // may throw DbExceptions! } // add(String), add(int, String), etc. ... } My problem lies with the fact that the underlying DB API may encounter connection errors that are not specified in the List interface that it should throw. My problem is whether this violates Liskov's Substitution Principle (LSP). Bob Martin actually gives an example of a PersistentSet in his paper on LSP that violates LSP. The difference is that his newly-specified Exception there is determined by the inserted value and so is strengthening the precondition. In my case the connection/read error is unpredictable and due to external factors and so is not technically a new precondition, merely an error of circumstance, perhaps like OutOfMemoryError which can occur even when unspecified. In normal circumstances, the new Error/Exception might never be thrown. (The caller could catch if it is aware of the possibility, just as a memory-restricted Java program might specifically catch OOME.) Is this therefore a valid argument for throwing an extra error and can I still claim to be a valid java.util.List (or pick your SDK/language/collection in general) and not in violation of LSP? If this does indeed violate LSP and thus not practically usable, I have provided two less-palatable alternative solutions as answers that you can comment on, see below. Footnote: Use Cases In the simplest case, the goal is to provide a familiar interface for cases when (say) a database is just being used as a persistent list, and allow regular List operations such as search, subList and iteration. Another, more adventurous, use-case is as a slot-in replacement for libraries that work with basic Lists, e.g if we have a third-party task queue that usually works with a plain List: new TaskWorkQueue(new ArrayList<String>()).start() which is susceptible to losing all it's queue in event of a crash, if we just replace this with: new TaskWorkQueue(new DbBackedList()).start() we get a instant persistence and the ability to share the tasks amongst more than one machine. In either case, we could either handle connection/read exceptions that are thrown, perhaps retrying the connection/read first, or allow them to throw and crash the program (e.g. if we can't change the TaskWorkQueue code).

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  • C#/.NET Little Wonders: Comparer&lt;T&gt;.Default

    - by James Michael Hare
    I’ve been working with a wonderful team on a major release where I work, which has had the side-effect of occupying most of my spare time preparing, testing, and monitoring.  However, I do have this Little Wonder tidbit to offer today. Introduction The IComparable<T> interface is great for implementing a natural order for a data type.  It’s a very simple interface with a single method: 1: public interface IComparer<in T> 2: { 3: // Compare two instances of same type. 4: int Compare(T x, T y); 5: }  So what do we expect for the integer return value?  It’s a pseudo-relative measure of the ordering of x and y, which returns an integer value in much the same way C++ returns an integer result from the strcmp() c-style string comparison function: If x == y, returns 0. If x > y, returns > 0 (often +1, but not guaranteed) If x < y, returns < 0 (often –1, but not guaranteed) Notice that the comparison operator used to evaluate against zero should be the same comparison operator you’d use as the comparison operator between x and y.  That is, if you want to see if x > y you’d see if the result > 0. The Problem: Comparing With null Can Be Messy This gets tricky though when you have null arguments.  According to the MSDN, a null value should be considered equal to a null value, and a null value should be less than a non-null value.  So taking this into account we’d expect this instead: If x == y (or both null), return 0. If x > y (or y only is null), return > 0. If x < y (or x only is null), return < 0. But here’s the problem – if x is null, what happens when we attempt to call CompareTo() off of x? 1: // what happens if x is null? 2: x.CompareTo(y); It’s pretty obvious we’ll get a NullReferenceException here.  Now, we could guard against this before calling CompareTo(): 1: int result; 2:  3: // first check to see if lhs is null. 4: if (x == null) 5: { 6: // if lhs null, check rhs to decide on return value. 7: if (y == null) 8: { 9: result = 0; 10: } 11: else 12: { 13: result = -1; 14: } 15: } 16: else 17: { 18: // CompareTo() should handle a null y correctly and return > 0 if so. 19: result = x.CompareTo(y); 20: } Of course, we could shorten this with the ternary operator (?:), but even then it’s ugly repetitive code: 1: int result = (x == null) 2: ? ((y == null) ? 0 : -1) 3: : x.CompareTo(y); Fortunately, the null issues can be cleaned up by drafting in an external Comparer.  The Soltuion: Comparer<T>.Default You can always develop your own instance of IComparer<T> for the job of comparing two items of the same type.  The nice thing about a IComparer is its is independent of the things you are comparing, so this makes it great for comparing in an alternative order to the natural order of items, or when one or both of the items may be null. 1: public class NullableIntComparer : IComparer<int?> 2: { 3: public int Compare(int? x, int? y) 4: { 5: return (x == null) 6: ? ((y == null) ? 0 : -1) 7: : x.Value.CompareTo(y); 8: } 9: }  Now, if you want a custom sort -- especially on large-grained objects with different possible sort fields -- this is the best option you have.  But if you just want to take advantage of the natural ordering of the type, there is an easier way.  If the type you want to compare already implements IComparable<T> or if the type is System.Nullable<T> where T implements IComparable, there is a class in the System.Collections.Generic namespace called Comparer<T> which exposes a property called Default that will create a singleton that represents the default comparer for items of that type.  For example: 1: // compares integers 2: var intComparer = Comparer<int>.Default; 3:  4: // compares DateTime values 5: var dateTimeComparer = Comparer<DateTime>.Default; 6:  7: // compares nullable doubles using the null rules! 8: var nullableDoubleComparer = Comparer<double?>.Default;  This helps you avoid having to remember the messy null logic and makes it to compare objects where you don’t know if one or more of the values is null. This works especially well when creating say an IComparer<T> implementation for a large-grained class that may or may not contain a field.  For example, let’s say you want to create a sorting comparer for a stock open price, but if the market the stock is trading in hasn’t opened yet, the open price will be null.  We could handle this (assuming a reasonable Quote definition) like: 1: public class Quote 2: { 3: // the opening price of the symbol quoted 4: public double? Open { get; set; } 5:  6: // ticker symbol 7: public string Symbol { get; set; } 8:  9: // etc. 10: } 11:  12: public class OpenPriceQuoteComparer : IComparer<Quote> 13: { 14: // Compares two quotes by opening price 15: public int Compare(Quote x, Quote y) 16: { 17: return Comparer<double?>.Default.Compare(x.Open, y.Open); 18: } 19: } Summary Defining a custom comparer is often needed for non-natural ordering or defining alternative orderings, but when you just want to compare two items that are IComparable<T> and account for null behavior, you can use the Comparer<T>.Default comparer generator and you’ll never have to worry about correct null value sorting again.     Technorati Tags: C#,.NET,Little Wonders,BlackRabbitCoder,IComparable,Comparer

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  • Not attending the LUGM mini-meetup - 05. Oct 2013

    Not attending a meeting of the LUGM can be fun, too. It's getting a bit of a habit that Ish is organising small gatherings, aka mini-meetups, of the Linux User Group Mauritius/Meta (LUGM) almost every Saturday. There they mainly discuss and talk about various elements of using Linux as ones main operating systems and the possibilities you are going to have. On top of course, some tips & tricks about mastering the command line and initial steps in scripting or even writing HTML. In general, sounds like a good portion of fun and great spirit of community. Unfortunately, I'm usually quite busy with private and family matters during the weekend and so I already signalised that I wouldn't be around. Well, at least not physically... But this Saturday a couple of things worked out faster than expected and so I was hanging out on my machine. I made virtual contact with one of Pawan's messages over on Facebook... And somehow that kicked off some kind of an online game fun on basic configuration of Apache HTTPd 2.2.x, PHP 5.x and how to improve the overall performance of a newly installed blog based on WordPress. Default configuration files Nitin's website finally came alive and despite the dark theme and the hidden Apple 'fanboy' advertisement I was more interested in the technical situation. As with any new installation there is usually quite some adjustment to be done. And Nitin's page was no exception. Unfortunately, out of the box installations of Apache httpd and PHP are too verbose and expose too much information under the hood. You might think that this isn't really a problem at all, well, think about it again after completely reading this article. First, I checked the HTTP response headers - using either Chrome Developer Tools or Firefox Web Developer extension - of Nitin's page and based on that I advised him to lower the noise levels a little bit. It's not really necessary that detailed information about web server software and scripting language has to be published in every response made. Quite a number of script kiddies and exploits actually check for version specifics prior to an attack. So, removing at least version details hardens the system a little bit. In particular, I'm talking about these response values: Server X-Powered-By How to achieve that? By tweaking the configuration files... Namely, we are going to look into the following ones: apache2.conf httpd.conf .htaccess php.ini The above list contains some additional files, I'm talking about in the next paragraphs. Anyway, those are the ones involved. Tweaking Apache Open your favourite text editor and start to modify the apache2.conf. Eventually, you might like to have a quick peak at the file to see whether it is necessary to adjust it or not. Following is a handy combination of commands to get an overview of your active directives: # sudo grep -v '#' /etc/apache2/apache2.conf | grep -v '^$' | less There you keep an eye on those two Apache directives: ServerSignature Off ServerTokens Prod If that's not the case, change them as highlighted above. In order to activate your modifications you have to restart Apache httpd server. On Debian and Ubuntu you might use apache2ctl for that, on other distributions you might have to use service or run the init-scripts again: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Refresh your website and check the HTTP response header. Tweaking PHP5 (a little bit) Next, check your php.ini file with the following statement: # sudo grep -v ';' /etc/php5/apache2/php.ini | grep -v '^$' | less And check the value of expose_php = Off Again, if it's not as highlighted, change it... Some more Apache love Okay, back to Apache it might also be interesting to improve the situation about browser caching and removing more obsolete information. When you run your website against the usual performance checks like Google Page Speed and Yahoo YSlow you might see those check points with bad grades on a standard, default configuration. Well, this can be done easily. Configure entity tags (ETags) ETags are only interesting when you run your websites on a farm of multiple web servers. Removing this data for your static resources is very simple in Apache. As we are going to deal with the HTTP response header information you have to ensure that Apache is capable to manipulate them. First, check your enabled modules: # sudo ls -al /etc/apache2/mods-enabled/ | grep headers And in case that the 'headers' module is not listed, you have to enable it from the available ones: # sudo a2enmod headers Second, check your httpd.conf file (in case it exists): # sudo grep -v '#' /etc/apache2/httpd.conf | grep -v '^$' | less In newer (better said fresh) installations you might have to create a new configuration file below your conf.d folder with your favourite text editor like so: # sudo nano /etc/apache2/conf.d/headers.conf Then, in order to tweak your HTTP responses either check for those lines or add them: Header unset ETagFileETag None In case that your file doesn't exist or those lines are missing, feel free to create/add them. Afterwards, check your Apache configuration syntax and restart your running instances as already shown above: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Add Expires headers To improve the loading performance of your website, you should take some care into the proper configuration of how to leverage the browser's ability to cache certain resources and files. This is done by adding an Expires: value to the HTTP response header. Generally speaking it is advised that you specify a near-future, read: 1 week or a little bit more, for your static content like JavaScript files or Cascading Style Sheets. One solution to adjust this is to put some instructions into the .htaccess file in the root folder of your web site. Of course, this could also be placed into a more generic location of your Apache installation but honestly, I'd like to keep this at the web site level. Following some adjustments I'm currently using on this blog site: # Turn on Expires and set default to 0ExpiresActive OnExpiresDefault A0 # Set up caching on media files for 1 year (forever?)<FilesMatch "\.(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav)$">ExpiresDefault A29030400Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 1 week<FilesMatch "\.(js|css)$">ExpiresDefault A604800Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 31 days<FilesMatch "\.(gif|jpg|jpeg|png|swf)$">ExpiresDefault A2678400Header append Cache-Control "public"</FilesMatch> As we are editing the .htaccess files, it is not necessary to restart Apache. In case that your web site doesn't load anymore or you're experiencing an error while trying to restart your httpd, check that the 'expires' module is actually an enabled module: # ls -al /etc/apache2/mods-enabled/ | grep expires# sudo a2enmod expires Of course, the instructions above a re not feature complete but I hope that they might provide a better default configuration for your LAMP stack. Resume of the day Within a couple of hours, and while being occupied with an eLearning course on SQL Server 2012, I had some good fun in helping and assisting other LUGM members while they were some kilometers away at Bagatelle. According to other blog articles it seems that Nitin had quite some moments of desperation. Just for the records: At no time it was my intention to either kick his butt or pull a leg on him. Simply, providing some input based on the lessons I've learned over the last couple of years configuring Apache HTTPd and PHP. Check out the other blogs, too: LUGM mini-meetup... Epic! Superb Saturday Linux Meetup And last but not least, the man himself: The end of a new beginning Cheers, and happy community'ing! Updates Due to our weekly Code & Coffee sessions in the MSCC community, I had a chance to talk to Nitin directly and he showed me the problems directly on his machine. This led to update this article hence the paragraphs on enabling the modules 'headers' and 'expires'.

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  • ApiChange Corporate Edition

    - by Alois Kraus
    In my inital announcement I could only cover a small subset what ApiChange can do for you. Lets look at how ApiChange can help you to fix bugs due to wrong usage of an Api within a fraction of time than it would take normally. It happens that software is tested and some bugs show up. One bug could be …. : We get way too man log messages during our test run. Now you have the task to find the most frequent messages and eliminate the Log calls from the source code. But what about the myriads other log calls? How can we check that the distribution of log calls is nearly equal across all developers? And if not how can we contact the developer to check his code? ApiChange can help you too connect these loose ends. It combines several information silos into one cohesive view. The picture below shows how it is able to fill the gaps. The public version does currently “only” parse the binaries and pdbs to give you for a –whousesmethod query the following colums: If it happens that you have Rational ClearCase (a source control system) in your development shop and an Active Directory in place then ApiChange will try to determine from the source file which was determined from the pdb the last check in user which should be present in your Active Directory. From there it is only a small hop to an LDAP query to your AD domain or the GC (Global Catalog) to get from the user name his Full name Email Phone number Department …. ApiChange will append this additional data all of your query results which contain source files if you add the –fileinfo option. As I said this is currently not enabled by default since the AD domain needs to be configured which are currently only some hard coded values in the SiteConstants.cs source file of ApiChange.Api.dll. Once you got this data you can generate metrics based on source file, developer, assembly, … and add additional data by drag and drop directly into the pivot tables inside Excel. This allows you to e.g. to generate a report which lists the source files with most log calls in descending order along with the developer name and email in the pivot table. Armed with this knowledge you can take meaningful measures e.g. to ask the developer if the huge number of log calls in this source file can be optimized. I am aware that this is a very specific scenario but it is a huge time saver when you are able to fill the missing gaps of information. ApiChange does this in an extensible way. namespace ApiChange.ExternalData {     public interface IFileInformationProvider     {         UserInfo GetInformationFromFile(string fileName);     } } It defines an interface where you can implement your custom information provider to close the gap between source control system and the real person I have to send an email to ask if his code needs a closer inspection.

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