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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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  • Customized Web Development Services

    Choosing between a web development company and a professional web development company is like choosing a rose from a bunch of thorns. In generic sense, every web development company offers elementary... [Author: Adam Mills - Web Design and Development - April 02, 2010]

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  • When to use SOAP over REST

    So, how does REST based services differ from SOAP based services, and when should you use SOAP? Representational State Transfer (REST) implements the standard HTTP/HTTPS as an interface allowing clients to obtain access to resources based on requested URIs. An example of a URI may look like this http://mydomain.com/service/method?parameter=var1&parameter=var2. It is important to note that REST based services are stateless because http/https is natively stateless. One of the many benefits for implementing HTTP/HTTPS as an interface is can be found in caching. Caching can be done on a web service much like caching is done on requested web pages. Caching allows for reduced web server processing and increased response times because content is already processed and stored for immediate access. Typical actions performed by REST based services include generic CRUD (Create, Read, Update, and Delete) operations and operations that do not require state. Simple Object Access Protocol (SOAP) on the other hand uses a generic interface in order to transport messages. Unlike REST, SOAP can use HTTP/HTTPS, SMTP, JMS, or any other standard transport protocols. Furthermore, SOAP utilizes XML in the following ways: Define a message Defines how a message is to be processed Defines the encoding of a message Lays out procedure calls and responses As REST aligns more with a Resource View, SOAP aligns more with a Method View in that business logic is exposed as methods typically through SOAP web service because they can retain state. In addition, SOAP requests are not cached therefore every request will be processed by the server. As stated before Soap does retain state and this gives it a special advantage over REST for services that need to preform transactions where multiple calls to a service are need in order to complete a task. Additionally, SOAP is more ideal for enterprise level services that implement standard exchange formats in the form of contracts due to the fact that REST does not currently support this. A real world example of where SOAP is preferred over REST can be seen in the banking industry where money is transferred from one account to another. SOAP would allow a bank to perform a transaction on an account and if the transaction failed, SOAP would automatically retry the transaction ensuring that the request was completed. Unfortunately, with REST, failed service calls must be handled manually by the requesting application. References: Francia, S. (2010). SOAP vs. REST. Retrieved 11 20, 2011, from spf13: http://spf13.com/post/soap-vs-rest Rozlog, M. (2010). REST and SOAP: When Should I Use Each (or Both)? Retrieved 11 20, 2011, from Infoq.com: http://www.infoq.com/articles/rest-soap-when-to-use-each

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  • Unable to boot post upgade to 12.10 from 12.04 on a dial boot PC

    - by Prateek
    I have a dual boot PC with Win7 and Ubuntu. Last night I upgraded from 12.04 to 12.10 and since then I have not been able to boot and PC goes into grub rescue with error "File not found" I have tried the below steps set prefix=(hd0,msdos5)/boot/grub/i386-pc/ set root=(hd0,msdos5) insmod normal ( i get error symbol not found : 'grub_disk_dev_list'. when I try linux /boot/vmlinuz-3.2.0-32-generic root=/dev/sda5 ro (i get error - command not found 'linux' ) same for initrd I am not able to find out what sdXX to set also.

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  • Securing WebSocket applications on Glassfish

    - by Pavel Bucek
    Today we are going to cover deploying secured WebSocket applications on Glassfish and access to these services using WebSocket Client API. WebSocket server application setup Our server endpoint might look as simple as this: @ServerEndpoint("/echo") public class EchoEndpoint { @OnMessage   public String echo(String message) {     return message + " (from your server)";   } } Everything else must be configured on container level. We can start with enabling SSL, which will require web.xml to be added to your project. For starters, it might look as following: <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee">   <security-constraint>     <web-resource-collection>       <web-resource-name>Protected resource</web-resource-name>       <url-pattern>/*</url-pattern>       <http-method>GET</http-method>     </web-resource-collection>     <!-- https -->     <user-data-constraint>       <transport-guarantee>CONFIDENTIAL</transport-guarantee>     </user-data-constraint>   </security-constraint> </web-app> This is minimal web.xml for this task - web-resource-collection just defines URL pattern and HTTP method(s) we want to put a constraint on and user-data-constraint defines that constraint, which is in our case transport-guarantee. More information about these properties and security settings for web application can be found in Oracle Java EE 7 Tutorial. I have some simple webpage attached as well, so I can test my endpoint right away. You can find it (along with complete project) in Tyrus workspace: [webpage] [whole project]. After deploying this application to Glassfish Application Server, you should be able to hit it using your favorite browser. URL where my application resides is https://localhost:8181/sample-echo-https/ (may be different, depends on other configuration). My browser warns me about untrusted certificate (I use what freshly built Glassfish provides - self signed certificates) and after adding an exception for this site, I can see my webpage and I am able to securely connect to wss://localhost:8181/sample-echo-https/echo. WebSocket client Already mentioned demo application also contains test client, but execution of this is skipped for normal build. Reason for this is that Glassfish uses these self-signed "random" untrusted certificates and you are (in most cases) not able to connect to these services without any additional settings. Creating test WebSocket client is actually quite similar to server side, only difference is that you have to somewhere create client container and invoke connect with some additional info. Java API for WebSocket allows you to use annotated and programmatic way to construct endpoints. Server side shows the annotated case, so let's see how the programmatic approach will look. final WebSocketContainer client = ContainerProvider.getWebSocketContainer(); client.connectToServer(new Endpoint() {   @Override   public void onOpen(Session session, EndpointConfig EndpointConfig) {     try {       // register message handler - will just print out the       // received message on standard output.       session.addMessageHandler(new MessageHandler.Whole<String>() {       @Override         public void onMessage(String message) {          System.out.println("### Received: " + message);         }       });       // send a message       session.getBasicRemote().sendText("Do or do not, there is no try.");     } catch (IOException e) {       // do nothing     }   } }, ClientEndpointConfig.Builder.create().build(),    URI.create("wss://localhost:8181/sample-echo-https/echo")); This client should work with some secured endpoint with valid certificated signed by some trusted certificate authority (you can try that with wss://echo.websocket.org). Accessing our Glassfish instance will require some additional settings. You can tell Java which certificated you trust by adding -Djavax.net.ssl.trustStore property (and few others in case you are using linked sample). Complete command line when you are testing your service might need to look somewhat like: mvn clean test -Djavax.net.ssl.trustStore=$AS_MAIN/domains/domain1/config/cacerts.jks\ -Djavax.net.ssl.trustStorePassword=changeit -Dtyrus.test.host=localhost\ -DskipTests=false Where AS_MAIN points to your Glassfish instance. Note: you might need to setup keyStore and trustStore per client instead of per JVM; there is a way how to do it, but it is Tyrus proprietary feature: http://tyrus.java.net/documentation/1.2.1/user-guide.html#d0e1128. And that's it! Now nobody is able to "hear" what you are sending to or receiving from your WebSocket endpoint. There is always room for improvement, so the next step you might want to take is introduce some authentication mechanism (like HTTP Basic or Digest). This topic is more about container configuration so I'm not going to go into details, but there is one thing worth mentioning: to access services which require authorization, you might need to put this additional information to HTTP headers of first (Upgrade) request (there is not (yet) any direct support even for these fundamental mechanisms, user need to register Configurator and add headers in beforeRequest method invocation). I filed related feature request as TYRUS-228; feel free to comment/vote if you need this functionality.

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  • The Sensemaking Spectrum for Business Analytics: Translating from Data to Business Through Analysis

    - by Joe Lamantia
    One of the most compelling outcomes of our strategic research efforts over the past several years is a growing vocabulary that articulates our cumulative understanding of the deep structure of the domains of discovery and business analytics. Modes are one example of the deep structure we’ve found.  After looking at discovery activities across a very wide range of industries, question types, business needs, and problem solving approaches, we've identified distinct and recurring kinds of sensemaking activity, independent of context.  We label these activities Modes: Explore, compare, and comprehend are three of the nine recognizable modes.  Modes describe *how* people go about realizing insights.  (Read more about the programmatic research and formal academic grounding and discussion of the modes here: https://www.researchgate.net/publication/235971352_A_Taxonomy_of_Enterprise_Search_and_Discovery) By analogy to languages, modes are the 'verbs' of discovery activity.  When applied to the practical questions of product strategy and development, the modes of discovery allow one to identify what kinds of analytical activity a product, platform, or solution needs to support across a spread of usage scenarios, and then make concrete and well-informed decisions about every aspect of the solution, from high-level capabilities, to which specific types of information visualizations better enable these scenarios for the types of data users will analyze. The modes are a powerful generative tool for product making, but if you've spent time with young children, or had a really bad hangover (or both at the same time...), you understand the difficult of communicating using only verbs.  So I'm happy to share that we've found traction on another facet of the deep structure of discovery and business analytics.  Continuing the language analogy, we've identified some of the ‘nouns’ in the language of discovery: specifically, the consistently recurring aspects of a business that people are looking for insight into.  We call these discovery Subjects, since they identify *what* people focus on during discovery efforts, rather than *how* they go about discovery as with the Modes. Defining the collection of Subjects people repeatedly focus on allows us to understand and articulate sense making needs and activity in more specific, consistent, and complete fashion.  In combination with the Modes, we can use Subjects to concretely identify and define scenarios that describe people’s analytical needs and goals.  For example, a scenario such as ‘Explore [a Mode] the attrition rates [a Measure, one type of Subject] of our largest customers [Entities, another type of Subject] clearly captures the nature of the activity — exploration of trends vs. deep analysis of underlying factors — and the central focus — attrition rates for customers above a certain set of size criteria — from which follow many of the specifics needed to address this scenario in terms of data, analytical tools, and methods. We can also use Subjects to translate effectively between the different perspectives that shape discovery efforts, reducing ambiguity and increasing impact on both sides the perspective divide.  For example, from the language of business, which often motivates analytical work by asking questions in business terms, to the perspective of analysis.  The question posed to a Data Scientist or analyst may be something like “Why are sales of our new kinds of potato chips to our largest customers fluctuating unexpectedly this year?” or “Where can innovate, by expanding our product portfolio to meet unmet needs?”.  Analysts translate questions and beliefs like these into one or more empirical discovery efforts that more formally and granularly indicate the plan, methods, tools, and desired outcomes of analysis.  From the perspective of analysis this second question might become, “Which customer needs of type ‘A', identified and measured in terms of ‘B’, that are not directly or indirectly addressed by any of our current products, offer 'X' potential for ‘Y' positive return on the investment ‘Z' required to launch a new offering, in time frame ‘W’?  And how do these compare to each other?”.  Translation also happens from the perspective of analysis to the perspective of data; in terms of availability, quality, completeness, format, volume, etc. By implication, we are proposing that most working organizations — small and large, for profit and non-profit, domestic and international, and in the majority of industries — can be described for analytical purposes using this collection of Subjects.  This is a bold claim, but simplified articulation of complexity is one of the primary goals of sensemaking frameworks such as this one.  (And, yes, this is in fact a framework for making sense of sensemaking as a category of activity - but we’re not considering the recursive aspects of this exercise at the moment.) Compellingly, we can place the collection of subjects on a single continuum — we call it the Sensemaking Spectrum — that simply and coherently illustrates some of the most important relationships between the different types of Subjects, and also illuminates several of the fundamental dynamics shaping business analytics as a domain.  As a corollary, the Sensemaking Spectrum also suggests innovation opportunities for products and services related to business analytics. The first illustration below shows Subjects arrayed along the Sensemaking Spectrum; the second illustration presents examples of each kind of Subject.  Subjects appear in colors ranging from blue to reddish-orange, reflecting their place along the Spectrum, which indicates whether a Subject addresses more the viewpoint of systems and data (Data centric and blue), or people (User centric and orange).  This axis is shown explicitly above the Spectrum.  Annotations suggest how Subjects align with the three significant perspectives of Data, Analysis, and Business that shape business analytics activity.  This rendering makes explicit the translation and bridging function of Analysts as a role, and analysis as an activity. Subjects are best understood as fuzzy categories [http://georgelakoff.files.wordpress.com/2011/01/hedges-a-study-in-meaning-criteria-and-the-logic-of-fuzzy-concepts-journal-of-philosophical-logic-2-lakoff-19731.pdf], rather than tightly defined buckets.  For each Subject, we suggest some of the most common examples: Entities may be physical things such as named products, or locations (a building, or a city); they could be Concepts, such as satisfaction; or they could be Relationships between entities, such as the variety of possible connections that define linkage in social networks.  Likewise, Events may indicate a time and place in the dictionary sense; or they may be Transactions involving named entities; or take the form of Signals, such as ‘some Measure had some value at some time’ - what many enterprises understand as alerts.   The central story of the Spectrum is that though consumers of analytical insights (represented here by the Business perspective) need to work in terms of Subjects that are directly meaningful to their perspective — such as Themes, Plans, and Goals — the working realities of data (condition, structure, availability, completeness, cost) and the changing nature of most discovery efforts make direct engagement with source data in this fashion impossible.  Accordingly, business analytics as a domain is structured around the fundamental assumption that sense making depends on analytical transformation of data.  Analytical activity incrementally synthesizes more complex and larger scope Subjects from data in its starting condition, accumulating insight (and value) by moving through a progression of stages in which increasingly meaningful Subjects are iteratively synthesized from the data, and recombined with other Subjects.  The end goal of  ‘laddering’ successive transformations is to enable sense making from the business perspective, rather than the analytical perspective.Synthesis through laddering is typically accomplished by specialized Analysts using dedicated tools and methods. Beginning with some motivating question such as seeking opportunities to increase the efficiency (a Theme) of fulfillment processes to reach some level of profitability by the end of the year (Plan), Analysts will iteratively wrangle and transform source data Records, Values and Attributes into recognizable Entities, such as Products, that can be combined with Measures or other data into the Events (shipment of orders) that indicate the workings of the business.  More complex Subjects (to the right of the Spectrum) are composed of or make reference to less complex Subjects: a business Process such as Fulfillment will include Activities such as confirming, packing, and then shipping orders.  These Activities occur within or are conducted by organizational units such as teams of staff or partner firms (Networks), composed of Entities which are structured via Relationships, such as supplier and buyer.  The fulfillment process will involve other types of Entities, such as the products or services the business provides.  The success of the fulfillment process overall may be judged according to a sophisticated operating efficiency Model, which includes tiered Measures of business activity and health for the transactions and activities included.  All of this may be interpreted through an understanding of the operational domain of the businesses supply chain (a Domain).   We'll discuss the Spectrum in more depth in succeeding posts.

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  • There is no driver for Ralink chip 5360

    - by Dmitrix
    I bought DWA-525 and it does not work Google did not help. No one on the Internet could not get the device to work =( lspci 01:06.0 Network controller: Ralink corp. Device 5360 I do not know what to do uname -a Linux pc 3.0.0-19-generic #33-Ubuntu SMP Thu Apr 19 19:05:57 UTC 2012 i686 athlon i386 GNU/Linux cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=11.10 DISTRIB_CODENAME=oneiric DISTRIB_DESCRIPTION="Ubuntu 11.10" I am sure that the problem is DWA-525 and chip 5360. I found many similar problems on the Internet without solving =(

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  • HighPoint RocketRAID 62x Controller

    - by TeXnewbie
    I have the subject card recently installed in Ubuntu 12.04.1 LTS (GNU/Linux 3.2.0-31-generic x86_64). See partial lspci -vv listing below (complete listing played havoc with pre tags): 03:00.0 RAID bus controller: HighPoint Technologies, Inc. Device 0622 (rev 01) Subsystem: HighPoint Technologies, Inc. Device 0001 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Latency: 0, Cache Line Size: 32 bytes Interrupt: pin A routed to IRQ 11 Region 0: I/O ports at 9c00 [size=8] Region 1: I/O ports at 9800 [size=4] Region 2: I/O ports at 9400 [size=8] Region 3: I/O ports at 9000 [size=4] Region 4: I/O ports at 8c00 [size=16] Region 5: Memory at fdbff000 (32-bit, non-prefetchable) [size=2K] Expansion ROM at fdbe0000 [disabled] [size=64K] Capabilities: I followed instructions I found at https://help.ubuntu.com/community/RocketRaid to compile the drivers for it, and although performing the process described there seemed to work fine with no noticeable errors, when I rebooted after performing that procedure I could not boot. During dkms steps, I noticed messages indicating that (If next boot fails, revert to initrd.img-3.2.0-31-generic.old-dkms image) update-initramfs................ so I booted using a Ubuntu 12.10 LiveDVD and reverted to the old-dkms initrd.img as suggested above, but this failed to repair the boot problem. Ultimately, I used https://help.ubuntu.com/community/Boot-Repair in Ubuntu-Secure-Remix to fix the boot problem and was able to boot normally again, but now with the newly generated initrd.img in place again (which now boots normally), when I modprobe the rr62x kernel module, I immediately get a hard crash with messages to console about a kernel paging request that seems to have caused the problem. I've tried on multiple occasions now to use the newly built kernel module so as to allow me to use an eSATA port multiplier plugged into the card, but to no avail. Any suggestions on fixes or workarounds (I've read that some of the HighPoint cards (2720SGL) seem to work as a host bus adapter and thus may not need a custom driver, but that seems not to be the case for mine) would be most appreciated. My goal is to use the card as described here and with software RAID mdadm utilities. If necessary, I can hand-copy the console messages after the hard crash into a follow-up message, but I obviously can't do a cut/paste. I'll gladly provide any other details that are needed, but not sure what those would be at this point, so I'll refrain from adding other details for now. Thanks in advance for any help.

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  • Customizing / overriding ComboBox (2 replies)

    Hi, I would override a Windows.Forms.Combobox to have a MyObjectCollection instead of a ObjectCollection as Items property. I've try writing this code, but it seems that items are stored somewhere else (not in Items property). I can add items to collection but when I try to select an item from the combobox (at runtime) an exception tells me that there is no such element in Items (litterally it tel...

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  • New Slides - and a discussion about Dictionary Statistics

    - by Mike Dietrich
    First of all we have just upoaded a new version of the Upgrade and Migration Workshop slides with some added information. So please feel free to download them from here.The slides have one new interesting information which lead to a discussion I've had in the past days with a very large customer regarding their upgrades - and internally on the mailing list targeting an EBS database upgrade from Oracle 10.2 to Oracle 11.2. Why are we creating dictionary statistics during upgrade? I'd believe this forced dictionary statistics creation got introduced with the desupport of the Rule Based Optimizer in Oracle 10g. The goal: as RBO is not supported anymore we have to make sure that the data dictionary has fresh and non-stale statistics. Actually that would have led in Oracle 9i to strange behaviour in some databases - so in Oracle 9i this was strongly disrecommended. The upgrade scripts got hardcoded to create these stats. But during tests we had the following findings: It's important to create dictionary statistics the night before the upgrade. Not two weeks before, not 60 minutes before your downtime begins. But very close to the upgrade. From Oracle 10g onwards you'd just say: $ execute DBMS_STATS.GATHER_DICTIONARY_STATS; This is important to make sure you have fresh dictionary statistics during upgrade for performance reasons. Tests have shown that running an upgrade without valid dictionary statistics might slow down the whole upgrade by factors of 2x-3x. And it would be also a great idea post upgrade to create again fresh dictionary statistics when you've did suppress the stats creation during the upgrade process. Suppress? Yes, you could set this underscore parameter in the init.ora: _optim_dict_stats_at_db_cr_upg=FALSE to suppress the forced dictionary statistics collection during an upgrade. We believe strongly that (a) people using the default statistics creation process which will create dictionary statistics by default and (b) create fresh stats before upgrade on the dictionary. Therefore we find it save once you have followed our advice to use the underscore during upgrade. And we've taken out that forced statistics collection during upgrade in the next release of the database. Please note: If you are using the DBUA for the upgrade it will remove underscore parameters for the upgrade run to improve performance - which is generally a good idea. So you'll have to start the DBUA with that call: $ dbua -initParam "_optim_dict_stats_at_cb_cr_upg"=FALSE -Mike

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  • Oracle ADF PMs are UKOUG Conference 2012

    - by Grant Ronald
    Next week we'll have a (what is a collection of PM's called, flock? gaggle?) of ADF Product Managers attending the UKOUG conference in Birmingham.  Myself, Frank Nimphius, Chris Muir, Susan Duncan, Frederic Desbiens and Duncan Mills will all be attending.  We'll be covering a range of sessions and if you have any questions you'd like to ask about Oracle tools development, technical questions, migration, Forms to ADF, futures, mobile, anything!, then come up and say hi.

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  • Adding complexity to remove duplicate code

    - by Phil
    I have several classes that all inherit from a generic base class. The base class contains a collection of several objects of type T. Each child class needs to be able to calculate interpolated values from the collection of objects, but since the child classes use different types, the calculation varies a tiny bit from class to class. So far I have copy/pasted my code from class to class and made minor modifications to each. But now I am trying to remove the duplicated code and replace it with one generic interpolation method in my base class. However that is proving to be very difficult, and all the solutions I have thought of seem way too complex. I am starting to think the DRY principle does not apply as much in this kind of situation, but that sounds like blasphemy. How much complexity is too much when trying to remove code duplication? EDIT: The best solution I can come up with goes something like this: Base Class: protected T GetInterpolated(int frame) { var index = SortedFrames.BinarySearch(frame); if (index >= 0) return Data[index]; index = ~index; if (index == 0) return Data[index]; if (index >= Data.Count) return Data[Data.Count - 1]; return GetInterpolatedItem(frame, Data[index - 1], Data[index]); } protected abstract T GetInterpolatedItem(int frame, T lower, T upper); Child class A: public IGpsCoordinate GetInterpolatedCoord(int frame) { ReadData(); return GetInterpolated(frame); } protected override IGpsCoordinate GetInterpolatedItem(int frame, IGpsCoordinate lower, IGpsCoordinate upper) { double ratio = GetInterpolationRatio(frame, lower.Frame, upper.Frame); var x = GetInterpolatedValue(lower.X, upper.X, ratio); var y = GetInterpolatedValue(lower.Y, upper.Y, ratio); var z = GetInterpolatedValue(lower.Z, upper.Z, ratio); return new GpsCoordinate(frame, x, y, z); } Child class B: public double GetMph(int frame) { ReadData(); return GetInterpolated(frame).MilesPerHour; } protected override ISpeed GetInterpolatedItem(int frame, ISpeed lower, ISpeed upper) { var ratio = GetInterpolationRatio(frame, lower.Frame, upper.Frame); var mph = GetInterpolatedValue(lower.MilesPerHour, upper.MilesPerHour, ratio); return new Speed(frame, mph); }

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  • Oracle Enterprise Manager Ops Center : Using Operational Profiles to Install Packages and other Content

    - by LeonShaner
    Oracle Enterprise Manager Ops Center provides numerous ways to deploy content, such as through OS Update Profiles, or as part of an OS Provisioning plan or combinations of those and other "Install Software" capabilities of Deployment Plans.  This short "how-to" blog will highlight an alternative way to deploy content using Operational Profiles. Usually we think of Operational Profiles as a way to execute a simple "one-time" script to perform a basic system administration function, which can optionally be based on user input; however, Operational Profiles can be much more powerful than that.  There is often more to performing an action than merely running a script -- sometimes configuration files, packages, binaries, and other scripts, etc. are needed to perform the action, and sometimes the user would like to leave such content on the system for later use. For shell scripts and other content written to be generic enough to work on any flavor of UNIX, converting the same scripts and configuration files into Solaris 10 SVR4 package, Solaris 11 IPS package, and/or a Linux RPM's might be seen as three times the work, for little appreciable gain.   That is where using an Operational Profile to deploy simple scripts and other generic content can be very helpful.  The approach is so powerful, that pretty much any kind of content can be deployed using an Operational Profile, provided the files involved are not overly large, and it is not necessary to convert the content into UNIX variant-specific formats. The basic formula for deploying content with an Operational Profile is as follows: Begin with a traditional script header, which is a UNIX shell script that will be responsible for decoding and extracting content, copying files into the right places, and executing any other scripts and commands needed to install and configure that content. Include steps to make the script platform-aware, to do the right thing for a given UNIX variant, or a "sorry" message if the operator has somehow tried to run the Operational Profile on a system where the script is not designed to run.  Ops Center can constrain execution by target type, so such checks at this level are an added safeguard, but also useful with the generic target type of "Operating System" where the admin wants the script to "do the right thing," whatever the UNIX variant. Include helpful output to show script progress, and any other informational messages that can help the admin determine what has gone wrong in the case of a problem in script execution.  Such messages will be shown in the job execution log. Include necessary "clean up" steps for normal and error exit conditions Set non-zero exit codes when appropriate -- a non-zero exit code will cause an Operational Profile job to be marked failed, which is the admin's cue to look into the job details for diagnostic messages in the output from the script. That first bullet deserves some explanation.  If Operational Profiles are usually simple "one-time" scripts and binary content is not allowed, then how does the actual content, packages, binaries, and other scripts get delivered along with the script?  More specifically, how does one include such content without needing to first create some kind of traditional package?   All that is required is to simply encode the content and append it to the end of the Operational Profile.  The header portion of the Operational Profile will need to contain the commands to decode the embedded content that has been appended to the bottom of the script.  The header code can do whatever else is needed, and finally clean up any intermediate files that were created during the decoding and extraction of the content. One way to encode binary and other content for inclusion in a script is to use the "uuencode" utility to convert the content into simple base64 ASCII text -- a form that is suitable to be appended to an Operational Profile.   The behavior of the "uudecode" utility is such that it will skip over any parts of the input that do not fit the uuencoded "begin" and "end" clauses.  For that reason, your header script will be skipped over, and uudecode will find your embedded content, that you will uuencode and paste at the end of the Operational Profile.  You can have as many "begin" / "end" clauses as you need -- just separate each embedded file by an empty line between "begin" and "end" clauses. Example:  Install SUNWsneep and set the system serial number Script:  deploySUNWsneep.sh ( <- right-click / save to download) Highlights: #!/bin/sh # Required variables: OC_SERIAL="$OC_SERIAL" # The user-supplied serial number for the asset ... Above is a good practice, showing right up front what kind of input the Operational Profile will require.   The right-hand side where $OC_SERIAL appears in this example will be filled in by Ops Center based on the user input at deployment time. The script goes on to restrict the use of the program to the intended OS type (Solaris 10 or older, in this example, but other content might be suitable for Solaris 11, or Linux -- it depends on the content and the script that will handle it). A temporary working directory is created, and then we have the command that decodes the embedded content from "self" which in scripting terms is $0 (a variable that expands to the name of the currently executing script): # Pass myself through uudecode, which will extract content to the current dir uudecode $0 At that point, whatever content was appended in uuencoded form at the end of the script has been written out to the current directory.  In this example that yields a file, SUNWsneep.7.0.zip, which the rest of the script proceeds to unzip, and pkgadd, followed by running "/opt/SUNWsneep/bin/sneep -s $OC_SERIAL" which is the command that stores the system serial for future use by other programs such as Explorer.   Don't get hung up on the example having used a pkgadd command.  The content started as a zip file and it could have been a tar.gz, or any other file.  This approach simply decodes the file.  The header portion of the script has to make sense of the file and do the right thing (e.g. it's up to you). The script goes on to clean up after itself, whether or not the above was successful.  Errors are echo'd by the script and a non-zero exit code is set where appropriate. Second to last, we have: # just in case, exit explicitly, so that uuencoded content will not cause error OPCleanUP exit # The rest of the script is ignored, except by uudecode # # UUencoded content follows # # e.g. for each file needed, #  $ uuencode -m {source} {source} > {target}.uu5 # then paste the {target}.uu5 files below # they will be extracted into the workding dir at $TDIR # The commentary above also describes how to encode the content. Finally we have the uuencoded content: begin-base64 444 SUNWsneep.7.0.zip UEsDBBQAAAAIAPsRy0Di3vnukAAAAMcAAAAKABUAcmVhZG1lLnR4dFVUCQADOqnVT7up ... VXgAAFBLBQYAAAAAAgACAJEAAADTNwEAAAA= ==== That last line of "====" is the base64 uuencode equivalent of a blank line, followed by "end" and as mentioned you can have as many begin/end clauses as you need.  Just separate each embedded file by a blank line after each ==== and before each begin-base64. Deploying the example Operational Profile looks like this (where I have pasted the system serial number into the required field): The job succeeded, but here is an example of the kind of diagnostic messages that the example script produces, and how Ops Center displays them in the job details: This same general approach could be used to deploy Explorer, and other useful utilities and scripts. Please let us know what you think?  Until next time...\Leon-- Leon Shaner | Senior IT/Product ArchitectSystems Management | Ops Center Engineering @ Oracle The views expressed on this [blog; Web site] are my own and do not necessarily reflect the views of Oracle. For more information, please go to Oracle Enterprise Manager  web page or  follow us at :  Twitter | Facebook | YouTube | Linkedin | Newsletter

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  • How to generate xorg.conf? (X -configure segfaults)

    - by Nicolas Raoul
    My video card is working fine, I have no screen problem. I am trying to generate an xorg.conf so I did: [ Logout ] sudo service gdm stop [ Move away xorg.conf.back and xorg.conf.fglrx-0 that were in /etc/X11 ] sudo dpkg-reconfigure xserver-xorg sudo X -configure But this last command segfaults: X.Org X Server 1.7.6 Release Date: 2010-03-17 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.6.24-27-server i686 Ubuntu Current Operating System: Linux nico 2.6.32-25-generic #44-Ubuntu SMP Fri Sep 17 20:26:08 UTC 2010 i686 Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.32-25-generic root=UUID=7447ab16-3406-442d-81e5-bb6a2d795205 ro quiet splash Build Date: 21 July 2010 12:47:34PM xorg-server 2:1.7.6-2ubuntu7.3 (For technical support please see http://www.ubuntu.com/support) Current version of pixman: 0.16.4 Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Fri Oct 15 16:06:11 2010 List of video drivers: i740 ark geode siliconmotion mach64 s3 r128 apm intel neomagic vesa trident chips s3virge fglrx sis savage rendition i128 tseng ztv mga openchrome radeon ati nv v4l vmware cirrus tdfx nouveau sisusb voodoo fbdev (EE) Can't load FireGL DRM library (libfglrxdrm.so). Backtrace: 0: X (xorg_backtrace+0x3b) [0x80e938b] 1: X (0x8048000+0x61c8d) [0x80a9c8d] 2: (vdso) (__kernel_rt_sigreturn+0x0) [0x34d410] 3: X (xf86CallDriverProbe+0x182) [0x80b82d2] 4: X (DoConfigure+0x1c8) [0x816b898] 5: X (InitOutput+0x1da) [0x80b98aa] 6: X (0x8048000+0x1ebbb) [0x8066bbb] 7: /lib/tls/i686/cmov/libc.so.6 (__libc_start_main+0xe6) [0x467bd6] 8: X (0x8048000+0x1e961) [0x8066961] Segmentation fault at address (nil) Caught signal 11 (Segmentation fault). Server aborting Please consult the The X.Org Foundation support at http://wiki.x.org for help. Please also check the log file at "/var/log/Xorg.0.log" for additional information. ddxSigGiveUp: Closing log Note the line Can't load FireGL DRM library (libfglrxdrm.so) Note: I do have file /usr/lib/fglrx/xorg/modules/linux/libfglrxdrm.so It is strange that it segfaults whereas I can use Gnome with no problem but well... Might be related: I tried to install the driver from ATI's website recently, and from then glxgears crashes at start. How can I generate xorg.conf in those conditions? It might or might not involve solving the segfault problem.

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  • What are these errors when I try to "make" the driver of my wireless adapter?

    - by Tom Brito
    I got got a wireless to usb adapter, and I'm having some trouble to install the drivers on Ubuntu. First of all, the readme says to use the make command, and I already got errors: $ make make[1]: Entering directory `/usr/src/linux-headers-2.6.35-22-generic' CC [M] /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.o /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c: In function ‘rtl8192_usb_probe’: /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12325: error: ‘struct net_device’ has no member named ‘open’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12326: error: ‘struct net_device’ has no member named ‘stop’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12327: error: ‘struct net_device’ has no member named ‘tx_timeout’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12328: error: ‘struct net_device’ has no member named ‘do_ioctl’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12329: error: ‘struct net_device’ has no member named ‘set_multicast_list’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12330: error: ‘struct net_device’ has no member named ‘set_mac_address’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12331: error: ‘struct net_device’ has no member named ‘get_stats’ /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.c:12332: error: ‘struct net_device’ has no member named ‘hard_start_xmit’ make[2]: *** [/home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u/r8192U_core.o] Error 1 make[1]: *** [_module_/home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/HAL/rtl8192u] Error 2 make[1]: Leaving directory `/usr/src/linux-headers-2.6.35-22-generic' make: *** [all] Error 2 /home/wellington/Desktop/rtl8192su_linux_2.4_2.6.0003.0301.2010/ is the path where I copied the drivers on my computer. Any idea how to solve this? (I don't even know what the error is...) update: sudo lshw -class network *-network description: Ethernet interface product: RTL8111/8168B PCI Express Gigabit Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:01:00.0 logical name: eth0 version: 03 serial: 78:e3:b5:e7:5f:6e size: 10MB/s capacity: 1GB/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd 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=r8169 driverversion=2.3LK-NAPI duplex=half latency=0 link=no multicast=yes port=MII speed=10MB/s resources: irq:42 ioport:d800(size=256) memory:fbeff000-fbefffff memory:faffc000-faffffff memory:fbec0000-fbedffff *-network DISABLED description: Wireless interface physical id: 2 logical name: wlan0 serial: 00:26:18:a1:ae:64 capabilities: ethernet physical wireless configuration: broadcast=yes multicast=yes wireless=802.11b/g

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  • The Many-to-Many Revolution 2.0 #ssas #mdx #dax #m2m

    - by Marco Russo (SQLBI)
    In September 2006 I had announced in this blog the release of the first version of The Many-to-Many Revolution, a whitepaper that describes how to leverage the many-to-many dimension relationships feature that had being available since Analysis Services 2005. The paper contains many generic patterns that can be applied in many common data analysis’ scenarios. More than 5 years later and more then 20.000 unique people that downloaded the 1.0 paper, I am proud to announce that we released The Many-to-Many...(read more)

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  • TFS Hosting: discountasp.net TFS

    - by Enrique Lima
    In the last month or so I have been able to test and experience first hand the offering from discountasp.net for hosted TFS 2010. This first part is a description of the setup process for the account itself and getting some additional information on what you will find through the portal on their site. Not long ago, I posted a little tidbit on hosting TFS.  Through it I also did a shameless plug to my employer, our services and the type of hosting we recommend.  So, wouldn’t me running on discountasp.net be an issue?  Actually? NO. Ok, enough rambling.  Let’s get some details here. It is a Software as a Service model.  Through it we get Source Control, Version Control, Work Item Tracking and such.  What about Build?  If your need includes Build Management and such, you may need to look at some other options.  But, still this is a great offering for those that are moving from SourceSafe.  Or organizations who have 3 to 5 developers on staff, and do not foresee getting larger anytime soon.  Can it support more than 5 developers?  Yes, but then we need to get into how are you using TFS.  Do you need more than just Basic?  For example, SharePoint and Reporting Services integration. The signup process was seamless! Very easy to follow, complete and transition to Visual Studio to start working. An email followed the signup process, it contained details on how to get to the Team Foundation Server Control Panel login.  Once there, here is what I saw after the initial setup process of naming my Team Project Collection: So, moving on … once I clicked the area to get my server info, I got the following: Then it was a matter of getting the first user in there: Then on to connecting Visual Studio to my hosted TFS. Getting the server information, and the user account created I will configure those options in Visual Studio. Using Team Explorer, I am adding a new server configuration. Once this is provided, click OK, I will be challenged for a username and password, provide them and you will land on the following screen. Then Click Close. You will now be connected to your server and Team Project Collection. Since this will likely be the first time connecting, you will have no Projects (I already have 2 going). Click Connect, and you will be back in Team Explorer. My next post in the topic will be on Creating your First Team Project and uploading a Project Template to the server.

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  • Custom Java Web Development vs Spreadsheet

    - by jacktrades
    Need some arguments why a small business should prefer a custom web developed solution using relational database (e.g. Java Servlet + MySQL) over standard Spreadsheet user programs like Excel. Specially now in these days that Office 365 is available in the cloud. As a Java programmer need good arguments to convince clients that this approach is better (if it really is) This is a generic situation, I understand that each case is different. Nevertheless answers so far has pinpointed right answers.

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  • Difference between the terms Material & Effect

    - by codey
    I'm making an effect system right now (I think, because it may be a material system... or both!). The effects system follows the common (e.g. COLLADA, DirectX) effect framework abstraction of Effects have Techniques, Techniques have Passes, Passes have States & Shader Programs. An effect, according to COLLADA, defines the equations necessary for the visual appearance of geometry and screen-space image processing. Keeping with the abstraction, effects contain techniques. Each effect can contain one or many techniques (i.e. ways to generate the effect), each of which describes a different method for rendering that effect. The technique could be relate to quality (e.g. high precision, high LOD, etc.), or in-game-situation (e.g. night/day, power-up-mode, etc.). Techniques hold a description of the textures, samplers, shaders, parameters, & passes necessary for rendering this effect using one method. Some algorithms require several passes to render the effect. Pipeline descriptions are broken into an ordered collection of Pass objects. A pass provides a static declaration of all the render states, shaders, & settings for "one rendering pipeline" (i.e. one pass). Meshes usually contain a series of materials that define the model. According to the COLLADA spec (again), a material instantiates an effect, fills its parameters with values, & selects a technique. But I see material defined differently in other places, such as just the Lambert, Blinn, Phong "material types/shaded surfaces", or as Metal, Plastic, Wood, etc. In game dev forums, people often talk about implementing a "material/effect system". Is the material not an instance of an effect? Ergo, if I had effect objects, stored in a collection, & each effect instance object with there own parameter setting, then there is no need for the concept of a material... Or am I interpreting it wrong? Please help by contributing your interpretations as I want to be clear on a distinction (if any), & don't want to miss out on the concept of a material if it should be implemented to follow the abstraction of the DirectX FX framework & COLLADA definitions closely.

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  • Alternative of SortedDictionary in Silverlight

    - by Rajneesh Verma
    Hi, As we know SortedDictionary is not not present in Silverlightso to find alternative of this i am using Dictionary as System.Collections.Generic . Dictionary (Of TKey, TValue ) . KeyCollection and for sorting i am using LINQ query. see the full code below. Dim sortedLists As New Dictionary(Of String, Object) Dim query = From sortedList In sortedLists Order By sortedList.Key Ascending Select sortedList.Key, sortedList.Value For Each que In query 'get the key value using que.Key 'get the value using...(read more)

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  • Why does Ubuntu crash/freeze so much?

    - by user204609
    I've been trying to watch a certain anime and it's taking me so long because I have to reboot 2-3 times per episode. It crashes very randomly, I can get through an episode without crashing, but if it does, everything stops moving, and I have to restart my computer. I've been having that problem in Lubuntu 13.04, Ubuntu 12.10, Ubuntu 13.04, Ubuntu 13.10 (the one I'm currently using), my kernel version 3.11.0-12-generic . Please help, this is really getting on my nerves. Thank you.

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  • Ubuntu won't save my settings for thinkpad trackpoint

    - by serve.chilled
    I'm using Ubuntu 12.04 on a Thinkpad X200. To configure the trackpoint, I use "configure TrackPoint". Unfortunately I can't make Ubuntu saving my settings (concerning the sensitivity etc.). Whenever I reboot the computer, it's set to generic settings again. I already tried htorque's answer to a similar question and created a new udev-rule for the trackpoint-settings but it didn't helped. So, how can I make theses settings permanent?

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  • If the net is required to install an Atheros 8161 driver,how do I connect to the net without the driver?

    - by Paul
    If Ubuntu does not recognize hardware to connect to the net, and a net connection is necessary in order to install drivers for hardware that connects to the net, then how is such a system ever going to connect to the net? You can see the situation in this thread: How do I install drivers for the Atheros AR8161 Ethernet controller? and in this thread: build-essential and linux-headers-generic gives abort message Surely, surely, there is a way out of this catch-22.

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