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• Simple collision detection in Unity 2D

  - by N1ghtshade3

  I realise other posts exist with this topic yet none have gone into enough detail for me. I am attempting to create a 2D game in Unity using C# as my scripting language. Basically I have two objects, player and bomb. Both were created simply by dragging the respective PNG to the stage. I have set up touch controls to move player left and right; gravity of any kind is not needed as I only require it to move x units when I tap either the left or right side of the screen. This movement is stored in a script called playerController.cs and works just fine. I also have a variable health = 3 for player, which is stored in healthScript.cs. I am now at a point where I am stuck. I would like it so that when player collides with bomb, health decreases by one and the bomb object is destroyed. So what I tried doing is using a new script called playerPhysics.cs, I added the following: void OnCollisionEnter2D(Collision2D coll){ if(coll.gameObject.name=="bomb") GameObject.Destroy("bomb"); healthScript.health -= 1; } While I'm fairly sure I don't know the proper way to reference a variable in another script and that's why the health didn't decrease when I collided, bomb never disappeared from the stage so I'm thinking there's also a problem with my collision. Initially, I had simply attached playerPhysics.cs to player. After searching around though, it appeared as though player also needed a rigidBody attached to it, so I did that. Still no luck. I tried using a circleCollider (player is a circle), using a rigidBody2D, and using all manner of colliders on one and/or both of the objects. If you could please explain what colliders (if any) should be attached to which objects and whether I need to change my script(s), that would be much more helpful than pointing me to one of the generic documentation examples I've already read. Also, if it would be simple to fix the health thing not working that would be an added bonus but not exactly the focus of this question. Bear in mind that this game is 2D; I'm not sure if that changes anything. Thanks!

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• Why do camera's aspect ratio look good on computer but not on Android devices?

  - by Pooya Fayyaz

  I'm developing a game for Android devices and I have a script that solves the aspect-ratio problem for computer screens but not for my intended target platform. It looks perfect on computer, even when re-sizing the game screen, but not when running my game in landscape mode on mobile phones. This is my script using UnityEngine; using System.Collections; using System.Collections.Generic; public class reso : MonoBehaviour { void Update() { // set the desired aspect ratio (the values in this example are // hard-coded for 16:9, but you could make them into public // variables instead so you can set them at design time) float targetaspect = 16.0f / 9.0f; // determine the game window's current aspect ratio float windowaspect = (float)Screen.width / (float)Screen.height; // current viewport height should be scaled by this amount float scaleheight = windowaspect / targetaspect; // obtain camera component so we can modify its viewport Camera camera = GetComponent<Camera>(); // if scaled height is less than current height, add letterbox if (scaleheight < 1.0f && Screen.width <= 490 ) { Rect rect = camera.rect; rect.width = 1.0f; rect.height = scaleheight; rect.x = 0; rect.y = (1.0f - scaleheight) / 2.0f; camera.rect = rect; } else // add pillarbox { float scalewidth = 1.0f / scaleheight; Rect rect = camera.rect; rect.width = scalewidth; rect.height = 1.0f; rect.x = (1.0f - scalewidth) / 2.0f; rect.y = 0; camera.rect = rect; } } } I figured that my problem occurs in this part of the script: if (scaleheight < 1.0f) { Rect rect = camera.rect; rect.width = 1.0f; rect.height = scaleheight; rect.x = 0; rect.y = (1.0f - scaleheight) / 2.0f; camera.rect = rect; } Its look like this on my mobile phone (portrait): and on landscape mode:

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• Push-Based Events in a Services Oriented Architecture

  - by Colin Morelli

  I have come to a point, in building a services oriented architecture (on top of Thrift), that I need to expose events and allow listeners. My initial thought was, "create an EventService" to handle publishing and subscribing to events. That EventService can use whatever implementation it desires to actually distribute the events. My client automatically round-robins service requests to available service hosts which are determined using Zookeeper-based service discovery. So, I'd probably use JMS inside of EventService mainly for the purpose of persisting messages (in the event that a service host for EventService goes down before it can distribute the message to all of the available listeners). When I started considering this, I began looking into the differences between Queues and Topics. Topics unfortunately won't work for me, because (at least for now), all listeners must receive the message (even if they were down at the time the event was pushed, or hadn't made a subscription yet because they haven't completed startup (during deployment, for example) - messages should be queued until the service is available). However, I don't want EventService to be responsible for handling all of the events. I don't think it should have the code to react to events inside of it. Each of the services should do what it needs with a given event. This would indicate that each service would need a JMS connection, which questions the value of having EventService at all (as the services could individually publish and subscribe to JMS directly). However, it also couples all of the services to JMS (when I'd rather that there be a single service that's responsible for determining how to distribute events). What I had thought was to publish an event to EventService, which pulls a configuration of listeners from some configuration source (database, flat file, irrelevant for now). It replicates the message and pushes each one back into a queue with information specific to that listener (so, if there are 3 listeners, 1 event would become 3 events in JMS). Then, another thread in EventService (which is replicated, running on multiple hots) would be pulling from the queue, attempting to make the service call to the "listener", and returning the message to the queue (if the service is down), or discarding the message (if the listener completed successfully). tl;dr If I have an EventService that is responsible for receiving events and delegating service calls to "event listeners," (which are really just endpoints on other services), how should it know how to craft the service call? Should I create a generic "Event" object that is shared among all services? Then, the EventService can just construct this object and pass it to the service call. Or is there a better answer to this problem entirely?

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• Enterprise Service Bus (ESB): Important architectural piece to a SOA or is it just vendor hype?

  Is an Enterprise Service Bus (ESB) an important architectural piece to a Service-Oriented Architecture (SOA), or is it just vendor hype in order to sell a particular product such as SOA-in-a-box? According to IBM.com, an ESB is a flexible connectivity infrastructure for integrating applications and services; it offers a flexible and manageable approach to service-oriented architecture implementation. With this being said, it is my personal belief that ESBs are an important architectural piece to any SOA. Additionally, generic design patterns have been created around the integration of web services in to ESB regardless of any vendor. ESB design patterns, according to Philip Hartman, can be classified in to the following categories: Interaction Patterns: Enable service interaction points to send and/or receive messages from the bus Mediation Patterns: Enable the altering of message exchanges Deployment Patterns: Support solution deployment into a federated infrastructure Examples of Interaction Patterns: One-Way Message Synchronous Interaction Asynchronous Interaction Asynchronous Interaction with Timeout Asynchronous Interaction with a Notification Timer One Request, Multiple Responses One Request, One of Two Possible Responses One Request, a Mandatory Response, and an Optional Response Partial Processing Multiple Application Interactions Benefits of the Mediation Pattern: Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently Design an intermediary to decouple many peers Promote the many-to-many relationships between interacting peers to “full object status” Examples of Interaction Patterns: Global ESB: Services share a single namespace and all service providers are visible to every service requester across an entire network Directly Connected ESB: Global service registry that enables independent ESB installations to be visible Brokered ESB: Bridges services that are reluctant to expose requesters or providers to ESBs in other domains Federated ESB: Service consumers and providers connect to the master or to a dependent ESB to access services throughout the network References: Mediator Design Pattern. (2011). Retrieved 2011, from SourceMaking.com: http://sourcemaking.com/design_patterns/mediator Hartman, P. (2006, 24 1). ESB Patterns that "Click". Retrieved 2011, from The Art and Science of Being an IT Architect: http://artsciita.blogspot.com/2006/01/esb-patterns-that-click.html IBM. (2011). WebSphere DataPower XC10 Appliance Version 2.0. Retrieved 2011, from IBM.com: http://publib.boulder.ibm.com/infocenter/wdpxc/v2r0/index.jsp?topic=%2Fcom.ibm.websphere.help.glossary.doc%2Ftopics%2Fglossary.html Oracle. (2005). 12 Interaction Patterns. Retrieved 2011, from Oracle® BPEL Process Manager Developer's Guide: http://docs.oracle.com/cd/B31017_01/integrate.1013/b28981/interact.htm#BABHHEHD

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• Playing with F#

  - by mroberts

  Project Euler is a awesome site.   When working with a new language it can be tricky to find problems that need solving, that are more complex than "Hello World" and simpler than a full blown application. Project Euler gives use just that, cool and thought provoking problems that usually don't take days to solve.  I've solved a number of questions with C# and some with Java.  BTW, I used Java because it had BigInteger support before .Net. A couple weeks ago, back when winter had a firm grip on Columbus, OH, I began playing (researching) with F#.  I began with Problem #1 from Project Euler.  I started by looking at my solution in C#. Here is my solution in C#. 1: using System; 2: using System.Collections.Generic; 3:   4: namespace Problem001 5: { 6: class Program 7: { 8: static void Main(string[] args) 9: { 10: List<int> values = new List<int>(); 11:   12: for (int i = 1; i < 1000; i++) 13: { 14: if (i % 3 == 0 || i % 5 == 0) 15: values.Add(i); 16: } 17: int total = 0; 18:   19: values.ForEach(v => total += v); 20:   21: Console.WriteLine(total); 22: Console.ReadKey(); 23: } 24: } 25: }   Now, after much tweaking and learning, here is my solution in F#.   1: open System 2:   3: let calc n = 4: [1..n] 5: |> List.map (fun x -> if (x % 3 = 0 || x % 5 = 0) then x else 0) 6: |> List.sum 7:   8: let main() = 9: calc 999 10: |> printfn "result = %d" 11: Console.ReadKey(true) |> ignore 12:   13: main() Just this little example highlights some cool things about F#. Type inference. F# infers the type of a value.  In the C# code above we declare a number of variables, the list, and a couple ints.  F# does not require this, it infers the calc (a function) accepts a int and returns a int. Great built in functionality for Lists.  List.map for example. BTW, I don’t think I’m spilling the beans by giving away the code for Problem 1.  It by far is the easiest question, IMHO, solved by 92,000+ people. Next I’ll look into writing a class library with F#.

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• Universities 2030: Learning from the Past to Anticipate the Future

  - by Mohit Phogat

  What will the landscape of international higher education look like a generation from now? What challenges and opportunities lie ahead for universities, especially “global” research universities? And what can university leaders do to prepare for the major social, economic, and political changes—both foreseen and unforeseen—that may be on the horizon? The nine essays in this collection proceed on the premise that one way to envision “the global university” of the future is to explore how earlier generations of university leaders prepared for “global” change—or at least responded to change—in the past. As the essays in this collection attest, many of the patterns associated with contemporary “globalization” or “internationalization” are not new; similar processes have been underway for a long time (some would say for centuries).[1] A comparative-historical look at universities’ responses to global change can help today’s higher-education leaders prepare for the future. Written by leading historians of higher education from around the world, these nine essays identify “key moments” in the internationalization of higher education: moments when universities and university leaders responded to new historical circumstances by reorienting their relationship with the broader world. Covering more than a century of change—from the late nineteenth century to the early twenty-first—they explore different approaches to internationalization across Europe, Asia, Australia, North America, and South America. Notably, while the choice of historical eras was left entirely open, the essays converged around four periods: the 1880s and the international extension of the “modern research university” model; the 1930s and universities’ attempts to cope with international financial and political crises; the 1960s and universities’ role in an emerging postcolonial international development apparatus; and the 2000s and the rise of neoliberal efforts to reform universities in the name of international economic “competitiveness.” Each of these four periods saw universities adopt new approaches to internationalization in response to major historical-structural changes, and each has clear parallels to today. Among the most important historical-structural challenges that universities confronted were: (1) fluctuating enrollments and funding resources associated with global economic booms and busts; (2) new modes of transportation and communication that facilitated mobility (among students, scholars, and knowledge itself); (3) increasing demands for applied science, technical expertise, and commercial innovation; and (4) ideological reconfigurations accompanying regime changes (e.g., from one internal regime to another, from colonialism to postcolonialism, from the cold war to globalized capitalism, etc.). Like universities today, universities in the past responded to major historical-structural changes by internationalizing: by joining forces across space to meet new expectations and solve problems on an ever-widening scale. Approaches to internationalization have typically built on prior cultural or institutional ties. In general, only when the benefits of existing ties had been exhausted did universities reach out to foreign (or less familiar) partners. As one might expect, this process of “reaching out” has stretched universities’ traditional cultural, political, and/or intellectual bonds and has invariably presented challenges, particularly when national priorities have differed—for example, with respect to curricular programs, governance structures, norms of academic freedom, etc. Strategies of university internationalization that either ignore or downplay cultural, political, or intellectual differences often fail, especially when the pursuit of new international connections is perceived to weaken national ties. If the essays in this collection agree on anything, they agree that approaches to internationalization that seem to “de-nationalize” the university usually do not succeed (at least not for long). Please continue reading the other essays at http://globalhighered.wordpress.com/

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• Oracle Spatial and Graph – A year in review

  - by Mandy Ho

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} What a great year for Oracle Spatial! Or shall I now say, Oracle Spatial and Graph, with our official name change this summer. There were so many exciting events and updates we had this year, and this blog will review and link to some of the events you may have missed over the year. We kicked off 2012 with our webinar: Situational Analysis at OnStar with Oracle Spatial and Graph. We collaborated with OnStar’s Emergency Strategy and Outreach expert, Jeff Joyner ,on how Onstar uses Google Earth Visualization, NAVTEQ data and Oracle Database to deliver fast, accurate emergency services to its customers. In the next webinar in our 2012 series, Oracle partner TARGUSinfo showcased how to build a robust, scalable and secure customer relationship management systems – with built-in mapping and spatial analysis, and deployed in the cloud. This is a very cool system using all Oracle technologies including Oracle Database and Fusion Middleware MapViewer. Attendees learned how to gather market insight, score prospects and customers and perform location analysis. The replay is available here. Our final webinar of the year focused on using Oracle Business Intelligence tools, along with Oracle Spatial and Graph to perform location-aware predictive analysis. Watch the webcast here: In June, we joined up with the Location Intelligence conference in Washington, DC, and had a very successful 2012 Oracle Spatial User Conference. Customers and partners from the US, as well as from EMEA and Asia, flew in to share experiences and ideas, and get technical updates from Oracle experts. Users were excited to hear about spatial-Exadata performance, and advances in MapViewer and BI. Peter Doolan of Oracle Public Sector kicked off the event with a great keynote, and US Census, NOAA, and Ordnance Survey Great Britain were just a few of the presenters. Presentation archive here. We recognized some of the most exceptional partners and customers for their contributions to advancing mainstream solutions using geospatial technologies. Planning for 2013’s conference has already started. Please contribute your papers for consideration here. http://www.locationintelligence.net/ We also launched a new Oracle PartnerNetwork Spatial Specialization – to enable partners to get validated in the marketplace for their expertise in taking solutions to market. Individuals can also get individual certifications. Learn more here. Oracle Open World was not to disappoint, with news regarding our next Oracle Spatial and Graph release, as well as the announcement of our new Oracle Spatial and Graph SIG board! Join the SIG today. One more exciting event as we look to 2013. Spatial and location technologies have a dedicated track at the January BIWA SIG Summit – on January 9-10 in Redwood Shores, CA. View the agenda and register here: www.biwasummit.org. We thank you for all your support during the year of 2012 and look towards an even more exciting 2013! Wishing you and your family a prosperous New Year and Happy Holidays!

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• Design pattern to handle queries using multiple models

  - by coderkane

  I am presented with a dilemma while trying to re-designing the class structure for my PHP/MySQL application to make it more elegant and conform it to the SOLID principle. The problem goes like this: Let as assume, there is an abstract class called person which has certain properties to define a generic person, such as name, age, date of birth etc. There are two classes, student, and teacher, that implements this abstract class. They add their own unique properties to it. I have designed all the three classes to include all the operational logic (details of which are not relevant in context of the question). Now, I need to create views/reports/data grids which contain details from multiple classes, for example, say, a list of all students doing projects in Chemistry mentored by a teacher whose name is the parameter to the query. This is just one example of a view, there are many different views in the application, which uses data from 3-4 tables, and each of them have multiple input parameters to generate them. Considering this particular example, I have written the relevant query using JOIN and the results are as expected and proper, now here is the dilemma: Keeping in mind the single responsibility principle, where should I keep this query? It does not belong to either Student class, or Teacher class or any other classes currently present. a) Should I create a new class, say dataView class, and design it as a MVC pattern and keep the query there? What about the other views? how do they fit in this architecture? b) Should I not keep the query in code at all, and make it DB View ? c) Am I completely wrong in the approach? If so what is the right approach? My considerations are as follows: a) should be easy to add new views later on if requirement comes, without having to copy-paste-modify code b) would like to make it as loosely coupled as possible so that if minor db structure changes happen, it does not break I did google searches on report design and OOP report generators, but all the result seem to focus on the visual design of the report rather than fetching the data. I have already taken care of the visual aspect of the report using MVC with html templates. I am sure this is a very fundamental problem with known solution, but I am somehow not able to find it (maybe searching with wrong keyword). Edit1: Modified the title to make it more relevant Edit2: The accepted answer got me thinking in the right direction and identify my design flaws, which eventually led me to find this question and the solution in Stack Overflow which gave me the detailed answer to clear the confusion.

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• When row estimation goes wrong

  - by Dave Ballantyne

  Whilst working at a client site, I hit upon one of those issues that you are not sure if that this is something entirely new or a bug or a gap in your knowledge. The client had a large query that needed optimizing.  The query itself looked pretty good, no udfs, UNION ALL were used rather than UNION, most of the predicates were sargable other than one or two minor ones.  There were a few extra joins that could be eradicated and having fixed up the query I then started to dive into the plan. I could see all manor of spills in the hash joins and the sort operations,  these are caused when SQL Server has not reserved enough memory and has to write to tempdb.  A VERY expensive operation that is generally avoidable.  These, however, are a symptom of a bad row estimation somewhere else, and when that bad estimation is combined with other estimation errors, chaos can ensue. Working my way back down the plan, I found the cause, and the more I thought about it the more i came convinced that the optimizer could be making a much more intelligent choice. First step is to reproduce and I was able to simplify the query down a single join between two tables, Product and ProductStatus,  from a business point of view, quite fundamental, find the status of particular products to show if ‘active’ ,’inactive’ or whatever. The query itself couldn’t be any simpler The estimated plan looked like this: Ignore the “!” warning which is a missing index, but notice that Products has 27,984 rows and the join outputs 14,000. The actual plan shows how bad that estimation of 14,000 is : So every row in Products has a corresponding row in ProductStatus.  This is unsurprising, in fact it is guaranteed,  there is a trusted FK relationship between the two columns.  There is no way that the actual output of the join can be different from the input. The optimizer is already partly aware of the foreign key meta data, and that can be seen in the simplifiction stage. If we drop the Description column from the query: the join to ProductStatus is optimized out. It serves no purpose to the query, there is no data required from the table and the optimizer knows that the FK will guarantee that a matching row will exist so it has been removed. Surely the same should be applied to the row estimations in the initial example, right ?  If you think so, please upvote this connect item. So what are our options in fixing this error ? Simply changing the join to a left join will cause the optimizer to think that we could allow the rows not to exist. or a subselect would also work However, this is a client site, Im not able to change each and every query where this join takes place but there is a more global switch that will fix this error,  TraceFlag 2301. This is described as, perhaps loosely, “Enable advanced decision support optimizations”. We can test this on the original query in isolation by using the “QueryTraceOn” option and lo and behold our estimated plan now has the ‘correct’ estimation. Many thanks goes to Paul White (b|t) for his help and keeping me sane through this

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• JGridView (Part 2)

  - by Geertjan

  The second sample in the JGrid download is a picture viewer that needs to be seen to be believed. Here it is, integrated into a NetBeans Platform application (click to enlarge it): When you mouse over the images, they change, showing several different images instantaneously. Here's the explorer view above, mainly making use of code from the sample: public class JGridView extends JScrollPane { @Override public void addNotify() { super.addNotify(); final ExplorerManager em = ExplorerManager.find(this); if (em != null) { final JGrid grid = new JGrid(); Node root = em.getRootContext(); final Node[] nodes = root.getChildren().getNodes(); final PicViewerObject[] pics = new PicViewerObject[nodes.length]; for (int i = 0; i < nodes.length; i++) { Node node = nodes[i]; pics[i] = node.getLookup().lookup(PicViewerObject.class); } grid.getCellRendererManager().setDefaultRenderer(new PicViewerRenderer()); grid.setModel(new DefaultListModel() { @Override public int getSize() { return pics.length; } @Override public Object getElementAt(int i) { return pics[i]; } }); grid.setFixedCellDimension(160); grid.addMouseMotionListener(new MouseAdapter() { int lastIndex = -1; @Override public void mouseMoved(MouseEvent e) { if (lastIndex >= 0) { Object o = grid.getModel().getElementAt(lastIndex); if (o instanceof PicViewerObject) { Rectangle r = grid.getCellBounds(lastIndex); if (r != null && !r.contains(e.getPoint())) { ((PicViewerObject) o).setMarker(false); grid.repaint(r); } } } int index = grid.getCellAt(e.getPoint()); if (index >= 0) { Object o = grid.getModel().getElementAt(index); if (o instanceof PicViewerObject) { Rectangle r = grid.getCellBounds(index); if (r != null) { ((PicViewerObject) o).setFraction(((float) e.getPoint().x - (float) r.x) / (float) r.width); ((PicViewerObject) o).setMarker(true); lastIndex = index; grid.repaint(r); } } } } }); grid.getSelectionModel().addListSelectionListener(new ListSelectionListener() { @Override public void valueChanged(ListSelectionEvent e) { //Somehow compare the selected item //with the list of books and find a matching book: int selectedIndex = grid.getSelectedIndex(); for (int i = 0; i < nodes.length; i++) { int picId = pics[i].getId(); if (selectedIndex == picId) { try { em.setSelectedNodes(new Node[]{nodes[i]}); } catch (PropertyVetoException ex) { Exceptions.printStackTrace(ex); } } } } }); setViewportView(grid); } } } The next step is to create a generic JGridView that will handle any kind of object automatically.

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• the unity aspect ratio script looks good in computer but not in android phones

  - by Pooya Fayyaz

  I'm developing a game for android devices.and i have a script that solve the ratio problem but i have a problem in this code.and i dont know why.it looks perfect in computer even resize the game screen but in mobile phones have a problem.my game runs in landscape mode.this is the script : using UnityEngine; using System.Collections; using System.Collections.Generic; public class reso : MonoBehaviour { void Update() { // set the desired aspect ratio (the values in this example are // hard-coded for 16:9, but you could make them into public // variables instead so you can set them at design time) float targetaspect = 16.0f / 9.0f; // determine the game window's current aspect ratio float windowaspect = (float)Screen.width / (float)Screen.height; // current viewport height should be scaled by this amount float scaleheight = windowaspect / targetaspect; // obtain camera component so we can modify its viewport Camera camera = GetComponent<Camera>(); // if scaled height is less than current height, add letterbox if (scaleheight < 1.0f && Screen.width <= 490 ) { Rect rect = camera.rect; rect.width = 1.0f; rect.height = scaleheight; rect.x = 0; rect.y = (1.0f - scaleheight) / 2.0f; camera.rect = rect; } else // add pillarbox { float scalewidth = 1.0f / scaleheight; Rect rect = camera.rect; rect.width = scalewidth; rect.height = 1.0f; rect.x = (1.0f - scalewidth) / 2.0f; rect.y = 0; camera.rect = rect; } } } i figure that my problem occur in this part of the script: if (scaleheight < 1.0f) { Rect rect = camera.rect; rect.width = 1.0f; rect.height = scaleheight; rect.x = 0; rect.y = (1.0f - scaleheight) / 2.0f; camera.rect = rect; } and its look like this in my mobile phone in portrait: and in landscape mode:

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• .Net Application & Database Modularity/Reuse

  - by Martaver

  I'm looking for some guidance on how to architect an app with regards to modularity, separation of concerns and re-usability. I'm working on an application (ASP.Net, C#) that has distinctly generic chunks of functionality, that I'd love to be able to lift out, all layers, into re-usable components. This means the module handles the database schema, data access, API, everything so that the next time I want to use it I can just register the module and hook into it. Developing modules of re-usable functionality is a no-brainer, but what is really confusing me is what to do when it comes to handling a core re-usable database schema that serves the module's functionality. In an ideal world, I would register a module and it would ensure that the associated database schema exists in the DB. I would code on the assumption that the tables exist, calling the module's functionality through the DLL, agnostic of the database layer. Kind of like Enterprise Library's Caching/Logging Application Block, which can create a DB schema in the target DB to use as a data store. My Questions is: What do you think is the best way to achieve this, firstly, in terms design architecture, and secondly solution structure. What patterns/frameworks do you know that exist & support this kind of thing? My thoughts so far: I mostly use Entity Framework and SQL Server DB Projects. I thought about a 'black box' approach to modules of functionality. I could use use a code-first approach in EF4, and use the ObjectContext to create a database when the module is initialized. However this means that all of the entities that my module encapsulates would be disconnected from the rest of the application because they belonged to an abstracted ObjectContext. Further - Creating appropriate indexes and references between domain entities and the module's entities would be impossible to do practically. I've thought of adopting Enterprise Library and creating my own Application Blocks. I'm not sure how this would play nice with Entity Framework (if at all) though. I like the idea of building on proven patterns & practices to encapsulate established, reusable functionality. I thought of abandoning Entity Framework for the Module, and just creating a separate DB schema for the module with its own set of stored procedures & ADO.Net. Then deploying the script at run-time if interrogation shows that it doesn't exist. But once again, for application developing outside of the application, I would want to use Entity Framework and I would have to use the module separately, disconnected from the domain ObjectContext. Has anyone had experience developing these sorts of full-stack modules? What advice can you offer? Am I biting off more than I can chew?

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• Compiling for T4

  - by Darryl Gove

  I've recently had quite a few queries about compiling for T4 based systems. So it's probably a good time to review what I consider to be the best practices. Always use the latest compiler. Being in the compiler team, this is bound to be something I'd recommend But the serious points are that (a) Every release the tools get better and better, so you are going to be much more effective using the latest release (b) Every release we improve the generated code, so you will see things get better (c) Old releases cannot know about new hardware. Always use optimisation. You should use at least -O to get some amount of optimisation. -xO4 is typically even better as this will add within-file inlining. Always generate debug information, using -g. This allows the tools to attribute information to lines of source. This is particularly important when profiling an application. The default target of -xtarget=generic is often sufficient. This setting is designed to produce a binary that runs well across all supported platforms. If the binary is going to be deployed on only a subset of architectures, then it is possible to produce a binary that only uses the instructions supported on these architectures, which may lead to some performance gains. I've previously discussed which chips support which architectures, and I'd recommend that you take a look at the chart that goes with the discussion. Crossfile optimisation (-xipo) can be very useful - particularly when the hot source code is distributed across multiple source files. If you're allowed to have something as geeky as favourite compiler optimisations, then this is mine! Profile feedback (-xprofile=[collect: | use:]) will help the compiler make the best code layout decisions, and is particularly effective with crossfile optimisations. But what makes this optimisation really useful is that codes that are dominated by branch instructions don't typically improve much with "traditional" compiler optimisation, but often do respond well to being built with profile feedback. The macro flag -fast aims to provide a one-stop "give me a fast application" flag. This usually gives a best performing binary, but with a few caveats. It assumes the build platform is also the deployment platform, it enables floating point optimisations, and it makes some relatively weak assumptions about pointer aliasing. It's worth investigating. SPARC64 processor, T3, and T4 implement floating point multiply accumulate instructions. These can substantially improve floating point performance. To generate them the compiler needs the flag -fma=fused and also needs an architecture that supports the instruction (at least -xarch=sparcfmaf). The most critical advise is that anyone doing performance work should profile their application. I cannot overstate how important it is to look at where the time is going in order to determine what can be done to improve it. I also presented at Oracle OpenWorld on this topic, so it might be helpful to review those slides.

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• C++11 Tidbits: Decltype (Part 2, trailing return type)

  - by Paolo Carlini

  Following on from last tidbit showing how the decltype operator essentially queries the type of an expression, the second part of this overview discusses how decltype can be syntactically combined with auto (itself the subject of the March 2010 tidbit). This combination can be used to specify trailing return types, also known informally as "late specified return types". Leaving aside the technical jargon, a simple example from section 8.3.5 of the C++11 standard usefully introduces this month's topic. Let's consider a template function like: template <class T, class U> ??? foo(T t, U u) { return t + u; } The question is: what should replace the question marks? The problem is that we are dealing with a template, thus we don't know at the outset the types of T and U. Even if they were restricted to be arithmetic builtin types, non-trivial rules in C++ relate the type of the sum to the types of T and U. In the past - in the GNU C++ runtime library too - programmers used to address these situations by way of rather ugly tricks involving __typeof__ which now, with decltype, could be rewritten as: template <class T, class U> decltype((*(T*)0) + (*(U*)0)) foo(T t, U u) { return t + u; } Of course the latter is guaranteed to work only for builtin arithmetic types, eg, '0' must make sense. In short: it's a hack. On the other hand, in C++11 you can use auto: template <class T, class U> auto foo(T t, U u) -> decltype(t + u) { return t + u; } This is much better. It's generic and a construct fully supported by the language. Finally, let's see a real-life example directly taken from the C++11 runtime library as implemented in GCC: template<typename _IteratorL, typename _IteratorR> inline auto operator-(const reverse_iterator<_IteratorL>& __x, const reverse_iterator<_IteratorR>& __y) -> decltype(__y.base() - __x.base()) { return __y.base() - __x.base(); } By now it should appear be completely straightforward. The availability of trailing return types in C++11 allowed fixing a real bug in the C++98 implementation of this operator (and many similar ones). In GCC, C++98 mode, this operator is: template<typename _IteratorL, typename _IteratorR> inline typename reverse_iterator<_IteratorL>::difference_type operator-(const reverse_iterator<_IteratorL>& __x, const reverse_iterator<_IteratorR>& __y) { return __y.base() - __x.base(); } This was guaranteed to work well with heterogeneous reverse_iterator types only if difference_type was the same for both types.

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• Java: How to manage UDP client-server state

  - by user92947

  I am trying to write a Java application that works similar to MapReduce. There is a server and several workers. Workers may come and go as they please and the membership to the group has a soft-state. To become a part of the group, the worker must send a UDP datagram to the server, but to continue to be part of the group, the worker must send the UDP datagram to the server every 5 minutes. In order to accommodate temporary errors, a worker is allowed to miss as many as two consecutive periodic UDP datagrams. So, the server must keep track of the current set of workers as well as the last time each worker had sent a UDP datagram. I've implemented a class called WorkerListener that implements Runnable and listens to UDP datagrams on a particular UDP port. Now, to keep track of active workers, this class may maintain a HashSet (or HashMap). When a datagram is received, the server may query the HashSet to check if it is a new member. If so, it can add the new worker to the group by adding an entry into the HashSet. If not, it must reset a "timer" for the worker, noting that it has just heard from the corresponding worker. I'm using the word timer in a generic sense. It doesn't have to be a clock of sorts. Perhaps this could also be implemented using int or long variables. Also, the server must run a thread that continuously monitors the timers for the workers to see that a client that times out on two consecutive datagram intervals, it is removed from the HashSet. I don't want to do this in the WorkerListener thread because it would be blocking on the UDP datagram receive() function. If I create a separate thread to monitor the worker HashSet, it would need to be a different class, perhaps WorkerRegistrar. I must share the HashSet with that thread. Mutual exclusion must also be implemented, then. My question is, what is the best way to do this? Pointers to some sample implementation would be great. I want to use the barebones JDK implementation, and not some fancy state maintenance API that takes care of everything, because I want this to be a useful demonstration for a class that I am teaching. Thanks

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• How to handle encryption key conflicts when synchronizing data?

  - by Rafael

  Assume that there is data that gets synchronized between several devices. The data is protected with a symmetric encryption algorithm and a key. The key is stored on each device and encrypted with a password. When a user changes the password only the key gets re-encrypted. Under normal circumstances, when there is a good network connection to other peers, the current key gets synchronized and all data on the new device gets encrypted with the same key. But how to handle situations where a new device doesn’t have a network connection and e.g. creates its own new, but incompatible key? How to keep the usability as high as possible under such circumstances? The application could detect that there is no network and hence refuse to start. That’s very bad usability in my opinion, because the application isn’t functional at all in this case. I don’t consider this a solution. The application could ignore the missing network connection and create a new key. But what to do when the application gains a network connection? There will be several incompatible keys and some parts of the underlying data could only be encrypted with one key and other parts with another key. The situation would get worse if there would be more keys than just two and the application would’ve to ask every time for a password when another object that should get decrypted with another key would be needed. It is very messy and time consuming to try to re-encrypt all data that is encrypted with another key with a main key. What should be the main key at all in this case? The oldest key? The key with the most encrypted objects? What if the key got synchronized but not all objects that got encrypted with this particular key? How should the user know for which particular password the application asks and why it takes probably very long to re-encrypt the data? It’s very hard to describe encryption “issues” to users. So far I didn’t find an acceptable solution, nor some kind of generic strategy. Do you have some hints about a concrete strategy or some books / papers that describe synchronization of symmetrically encrypted data with keys that could cause conflicts?

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• Are there any concerns with using a static read-only unit of work so that it behaves like a cache?

  - by Rowan Freeman

  Related question: How do I cache data that rarely changes? I'm making an ASP.NET MVC4 application. On every request the security details about the user will need to be checked with the area/controller/action that they are accessing to see if they are allowed to view it. The security information is stored in the database. For example: User Permission UserPermission Action ActionPermission A "Permission" is a token that is applied to an MVC action to indicate that the token is required in order to access the action. Once a user is given the permission (via the UserPermission table) then they have the token and can therefore access the action. I've been looking in to how to cache this data (since it rarely changes) so that I'm only querying in-memory data and not hitting a database (which is a considerable performance hit at the moment). I've tried storing things in lists, using a caching provider but I either run in to problems or performance doesn't improve. One problem that I constantly run in to is that I'm using lazy loading and dynamic proxies with EntityFramework. This means that even if I ToList() everything and store them somewhere static, the relationships are never populated. For example, User.Permissions is an ICollection but it's always null. I don't want to Include() everything because I'm trying to keep things simple and generic (and easy to modify). One thing I know is that an EntityFramework DbContext is a unit of work that acts with 1st-level caching. That is, for the duration of the unit of work, everything that is accessed is cached in memory. I want to create a read-only DbContext that will exist indefinitely and will only be used to read about permission data. Upon testing this it worked perfectly; my page load times went from 200ms+ to 20ms. I can easily force the data to refresh at certain intervals or simply leave it to refresh when the application pool is recycled. Basically it will behave like a cache. Note that the rest of the application will interact with other contexts that exist per request as normal. Is there any disadvantage to this approach? Could I be doing something different?

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• OpenWorld: Our (Road) Maps are Looking Good!

  - by Tony Berk

  Wow, only one (or two) days down at Oracle OpenWorld! Are you on overload yet? I'm still trying to figure out how to be in 3 sessions at the same time... I guess everyone needs to prioritize! There was a lot to see in Monday's sessions, especially some great forward-looking roadmap sessions. In case you aren't here or you decided to go to other sessions, this is my quick summary of what I could capture from a couple of the roadmaps: In the Fusion CRM Strategy and Roadmap session, Anthony Lye provided an overview of the Fusion CRM strategy including the key design principles of 3 E's: Easy, Effective and Efficient. After an overview of how Oracle has deployed Fusion CRM internally to 25,000 users worldwide, Anthony discussed the features coming in the next release, the releases in the next 12 months and beyond. I can't detail too much since you haven't read Oracle's Safe Harbor statement, but check out Fusion Tap and look for new features and added functionality for sales prediction, marketing, social and integration with a number of the key Customer Experience products.  In the Oracle RightNow CX Cloud Service Vision and Roadmap session, Chris Hamilton presented the focus areas for the RightNow product. As a result of the large increase in development resources after the acquisition, the RightNow CX team is planning a lot of enhancements to the functionality, infrastructure and integrations. As a key piece of the Oracle Customer Experience (CX) strategy, RightNow will be integrated with Oracle Social Network, Oracle Commerce (ATG and Endeca), Oracle Knowledge, Oracle Policy Automation and, of course, further integration with Fusion Sales and Marketing. Look forward to seeing more on the Virtual Assistant, Smart Interaction Hub and Mobility. In addition to the roadmaps, I was looking forward to hearing from Oracle CRM customers. So, I sat in on two great Siebel customer panels: The Maximizing User Adoption Rates for Siebel Sales and Siebel Partner Relationship Management panel consisted of speakers from CSL Behring, McKesson and Intuit. It was great to get an overview of implementations for both B2B and B2C companies. It was great hearing that all of these companies have more than 1,000 sales users (Intuit has 4,000) and how the 360 degree view of the customer in Siebel is helping these customers improve their customers' experience (CX). They are all great examples of centralized implementations which have standardized processes across the globe and across business units.  Waste Management, Farmers Insurance and the US Citizenship & Immigration Services presented in the Driving Great Customer Experiences with Siebel Service Applications session. Talk about serving large customer bases! Is it possible that Farmers with only 10 million households is the smallest of these 3? All of them provided great examples of how they are improving the customer experience (CX) including 60-70% improvements in efficiency or reducing the number of applications the customer service reps (CSRs) need to use from 10 to 1 (Waste Management) and context aware call transfers to avoid the caller explaining their issue 3 times (USCIS). So that's my wrap up of only 4 sessions from Monday. In between sessions, I stopped by the Oracle DEMOgrounds and CRM Pavilion to visit with a group of great partners and see the products and partner integrations in action. Don't miss a recap of Mark Hurd's Keynote. I can't believe there were another 40+ sessions covering CRM, Fusion, Cloud, etc. that I missed today! Anyone else see any great sessions?

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• Resources to Help You Getting Up To Speed on ADF Mobile

  - by Joe Huang

  Hi, everyone: By now, I hope you would have a chance to review the sample applications and try to deploy it.  This is a great way to get started on learning ADF Mobile.  To help you getting started, here is a central list of "steps to get up to speed on ADF Mobile" and related resources that can help you developing your mobile application. Check out the ADF Mobile Landing Page on the Oracle Technology Network. View this introductory video. Read this Data Sheet and FAQ on ADF Mobile. JDeveloper 11.1.2.3 Download. Download the generic version of JDeveloper for installation on Mac. Note that there are workarounds required to install JDeveloper on a Mac. Download ADF Mobile Extension from JDeveloper Update Center or Here. Please note you will need to configure JDeveloper for Internet access (In HTTP Proxy preferences) in order the install the extension, as the installation process will prompt you for a license that's linked off Oracle's web site. View this end-to-end application creation video. View this end-to-end iOS deployment video if you are developing for iOS devices. Configure your development environment, including location of the SDK, etc in JDeveloper-Tools-Preferences-ADF Mobile dialog box.  The two videos above should cover some of these configuration steps. Check out the sample applications shipped with JDeveloper, and then deploy them to simulator/devices using the steps outlined in the video above.  This blog entry outlines all sample applications shipped with JDeveloper. Develop a simple mobile application by following this tutorial. Try out the Oracle Open World 2012 Hands on Lab to get a sense of how to programmatically access server data.  You will need these source files. Ask questions in the ADF/JDeveloper Forum. Search ADF Mobile Preview Forum for entries from ADF Mobile Beta Testing participants. For all other questions, check out this exhaustive and detailed ADF Mobile Developer Guide. If something does not seem right, check out the ADF Mobile Release Note. Thanks, Oracle ADF Mobile Product Management Team

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• Get Fanatical About Your Followers

  - by Mike Stiles

  In the fourth of our series of discussions with Aberdeen’s Trip Kucera, we touch on what fans of your brand have come to expect in exchange for their fandom. Spotlight: Around the Oracle Social office, we live for football. So when we think of a true “fan” of a brand, something on the level of a football fan is what comes to mind. But are brands trying to invest fans on that same level? Trip: Yeah, if you’re a football fan, this is definitely your time of year. And if you’ve been to any NFL games recently, especially if you hadn’t been for a few years previously, you may have noticed that from the cup holders to in-stadium Wi-Fi, there’s an increasing emphasis being placed on “fan-focused” accommodations. That’s what they’re known as in the stadium business. Spotlight: How are brands doing in that fan-focused arena? Trip: Remember fan is short for “fanatical.” Brands can definitely learn from the way teams have become fanatical about their fans, or in the social media world, their followers. Many companies consider a segment of their addressable social audience as true fans; I’ve even heard the term “super-fans” used. So just as fans know and can tell you nearly everything about their favorite team, our research shows that there’s a lot value from getting to know your social audience—your followers—at a deeper level. Spotlight: So did your research show there’s a lot to be gained by making fandom a two-way street? Trip: Aberdeen’s new social relationship management research suggests that companies should develop capabilities to better analyze their social audience at a more granular level. Countless “ripped from the headlines” examples, from “United Breaks Guitars” to the most recent British Airways social fiasco we talked about a few weeks ago show how social can magnify the impact of a single customer voice. Spotlight: So how do the companies who are executing social most successfully do that? Trip: Leaders, which are the top-performing companies in Aberdeen’s study, are showing the value of identifying and categorizing your social audience. You should certainly treat every customer as if they have 10,000 followers, because they just might, but you can also proactively engage with high-value customer and high-value influencers. Getting back to the football analogy, it’s like how teams strive to give every guest a great experience, but they really roll out the red carpet for those season ticket and luxury box holders. Spotlight: I’m not allowed in luxury boxes, so you’ll have to tell me what that’s like. But what is the brand equivalent of rolling out the red carpet? Trip: Leaders are nearly three times more likely than Followers to have a process in place that identifies key social influencers for engagement, and more than twice as likely to identify customer advocates for social outreach. This is the kind of knowledge that gives companies the ability to better target social messaging and promotions like we talked about in our last discussion, as well as a basis for understanding how to measure the impact of their social media programs. I’ll give you an example. I hosted an event at one of my favorite restaurants recently. I had mentioned them in a Tweet several weeks before the event, and on the day of the event, they Tweeted out that they were looking forward to seeing me that evening for the event. It’s a small thing, but it had a big impact and I’d certainly go back as a result. Spotlight: So what specifically can brands use and look at to determine where their potential super-fans are? Trip: Social graph analysis, which looks at both the demographic/psychographic trends as well as the behavioral connections, can surface important brand value. Aberdeen’s PR and Brand Management research indicated that top-performing companies are more than three times more likely than Followers to both determine demographic trends through social listening (44% vs. 13%), and to identify meaningful customer segments through social (44% vs. 12%). This kind of brand-level insight can complement and enrich traditional market research. But perhaps even more importantly, it can serve as an early warning system for customer experience failures. @mikestilesPhoto: freedigitalphotos.net

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• Support ARMv7 instruction set in Windows Embedded Compact applications

  - by Valter Minute

  On of the most interesting new features of Windows Embedded Compact 7 is support for the ARMv5, ARMv6 and ARMv7 instruction sets instead of the ARMv4 “generic” support provided by the previous releases. This means that code build for Windows Embedded Compact 7 can leverage features (like the FPU unit for ARMv6 and v7) and instructions of the recent ARM cores and improve their performances. Those improvements are noticeable in graphics, floating point calculation and data processing. The ARMv7 instruction set is supported by the latest Cortex-A8, A9 and A15 processor families. Those processor are currently used in tablets, smartphones, in-car navigation systems and provide a great amount of processing power and a low amount of electric power making them very interesting for portable device but also for any kind of device that requires a rich user interface, processing power, connectivity and has to keep its power consumption low. The bad news is that the compiler provided with Visual Studio 2008 does not provide support for ARMv7, building native applications using just the ARMv4 instruction set. Porting a Visual Studio “Smart Device” native C/C++ project to Platform Builder is not easy and you’ll lack many of the features that the VS2008 application development environment provides. You’ll also need access to the BSP and OSDesign configuration for your device to be able to build and debug your application inside Platform Builder and this may prevent independent software vendors from using the new compiler to improve their applications performances. Adeneo Embedded now provides a whitepaper and a Visual Studio plug-in that allows usage of the new ARMv7 enabled compiler to build applications inside Visual Studio 2008. I worked on the whitepaper and the tools, with the help of my colleagues and now the results can be downloaded from Adeneo Embedded’s website: http://www.adeneo-embedded.com/OS-Technologies/Windows-Embedded (Click on the “WEC7 ARMv7 Whitepaper tab to access the download links, free registration required) A very basic benchmark showed a very good performance improvement in integer and floating-point operations. Obviously your mileage may vary and we can’t promise the same amount of improvement on any application, but with a small effort on your side (even smaller if you use the plug-in) you can try on your own application. ARMv7 support is provided using Platform Builder’s compiler and VS2008 application debugger is not able to debut ARMv7 code, so you may need to put in place some workaround like keeping ARMv4 code for debugging etc.

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• Changing Silverlight application themes at runtime

  We have received a lot of questions how can the application theme be changed at run time. The most important thing here to mark is that each time the application theme is changed all the controls should be re-drawn. Without going into too much detail, we could explain the application themes as a mechanism to replace the content of the Generic.xaml file in every loaded Telerik assembly at runtime. This does not affect the controls that already have default style applied, hence the need to create new instances. Because in the Silverlight applications the RootVisual cannot be changed at run time, we need a way to reset the application UI. The following code is in App.xaml.cs. private void Application_Startup(object sender, StartupEventArgs e)     {           // Before:           // this.RootVisual = new MainPage();            this.RootVisual = new Grid();         this.ResetRootVisual();     }        public void ResetRootVisual()     {         var rootVisual = Application.Current.RootVisual as Grid;         rootVisual.Children.Clear();         rootVisual.Children.Add(new MainPage());     }   In Application_Startup() instead of creating new MainPage UserControl instance as RootVisual, we create a new Grid panel, that will contain the MainPage UserControl. In the ResetRootVisual() method we create the instance of MainPage and add it to the RootVisual panel. Then we have to create a method in the code behind which will set StyleManager.ApplicationTheme and then will call the ResetRootVisual() method: private void ChangeApplicationTheme(Theme theme) {     StyleManager.ApplicationTheme = theme;     (Application.Current as App).ResetRootVisual(); }   Here you can find an example which illustrates the described implementation of a Silverlight theme. For more information please refer to Teleriks online demos for Silverlight, the demos for WPF and help documentation for WPF and help documentation for Silverlight. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Mutable Records in F#

  - by MarkPearl

  I’m loving my expert F# book – today I thought I would give a post on using mutable records as covered in Chapter 4 of Expert F#. So as they explain the simplest mutable data structures in F# are mutable records. The whole concept of things by default being immutable is a new one for me from my C# background. Anyhow… lets look at some C# code first. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace MutableRecords { public class DiscreteEventCounter { public int Total { get; set; } public int Positive { get; set; } public string Name { get; private set; } public DiscreteEventCounter(string name) { Name = name; } } class Program { private static void recordEvent(DiscreteEventCounter s, bool isPositive) { s.Total += 1; if (isPositive) s.Positive += 1; } private static void reportStatus (DiscreteEventCounter s) { Console.WriteLine("We have {0} {1} out of {2}", s.Positive, s.Name, s.Total); } static void Main(string[] args) { var longCounter = new DiscreteEventCounter("My Discrete Counter"); recordEvent(longCounter, true); recordEvent(longCounter, true); reportStatus(longCounter); Console.ReadLine(); } } } Quite simple, we have a class that has a few values. We instantiate an instance of the class and perform increments etc on the instance. Now lets look at an equivalent F# sample. namespace EncapsulationNS module Module1 = open System type DiscreteEventCounter = { mutable Total : int mutable Positive : int Name : string } let recordEvent (s: DiscreteEventCounter) isPositive = s.Total <- s.Total+1 if isPositive then s.Positive <- s.Positive+1 let reportStatus (s: DiscreteEventCounter) = printfn "We have %d %s out of %d" s.Positive s.Name s.Total let newCounter nm = { Total = 0; Positive = 0; Name = nm } // // Using it... // let longCounter = newCounter "My Discrete Counter" recordEvent longCounter (true) recordEvent longCounter (true) reportStatus longCounter System.Console.ReadLine() Notice in the type declaration of the DiscreteEventCounter we had to explicitly declare that the total and positive value holders were mutable. And that’s it – a very simple example of mutable types.

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• Accessing SQL Server data from iOS apps

  - by RobertChipperfield

  Almost all mobile apps need access to external data to be valuable. With a huge amount of existing business data residing in Microsoft SQL Server databases, and an ever-increasing drive to make more and more available to mobile users, how do you marry the rather separate worlds of Microsoft's SQL Server and Apple's iOS devices? The classic answer: write a web service layer Look at any of the questions on this topic asked in Internet discussion forums, and you'll inevitably see the answer, "just write a web service and use that!". But what does this process gain? For a well-designed database with a solid security model, and business logic in the database, writing a custom web service on top of this just to access some of the data from a different platform seems inefficient and unnecessary. Desktop applications interact with the SQL Server directly - why should mobile apps be any different? The better answer: the iSql SDK Working along the lines of "if you do something more than once, make it shared," we set about coming up with a better solution for the general case. And so the iSql SDK was born: sitting between SQL Server and your iOS apps, it provides the simple API you're used to if you've been developing desktop apps using the Microsoft SQL Native Client. It turns out a web service remained a sensible idea: HTTP is much more suited to the Big Bad Internet than SQL Server's native TDS protocol, removing the need for complex configuration, firewall configuration, and the like. However, rather than writing a web service for every app that needs data access, we made the web service generic, serving only as a proxy between the SQL Server and a client library integrated into the iPhone or iPad app. This client library handles all the network communication, and provides a clean API. OSQL in 25 lines of code As an example of how to use the API, I put together a very simple app that allowed the user to enter one or more SQL statements, and displayed the results in a rather primitively formatted text field. The total amount of Objective-C code responsible for doing the work? About 25 lines. You can see this in action in the demo video. Beta out now - your chance to give us your suggestions! We've released the iSql SDK as a beta on the MobileFoo website: you're welcome to download a copy, have a play in your own apps, and let us know what we've missed using the Feedback button on the site. Software development should be fun and rewarding: no-one wants to spend their time writing boiler-plate code over and over again, so stop writing the same web service code, and start doing exciting things in the new world of mobile data!

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• Parallel Port Problem in 12.04

  - by Frank Oberle

  I have a “dumb” printer attached to a parallel port in my machine which works fine under the “other” resident operating system (from Redmond) on the same machine. I recently added Ubuntu 12.04 as a dual boot on the machine, but Ubuntu doesn't seem to recognize the parallel port at all. All I need to set up a printer is a really plain-vanilla fixed pitch text-only generic driver, which is present, but no parallel ports show up. (The other printers, all on USB ports, seem to work just fine). Following what appeared to me to be the most reasonable of the many conflicting pieces of advice on the web, here's what I did: I added the following lines to /etc/modules parport_pc ppdev parport Then, after rebooting, I checked to see that the lines were still present, and they were. I ran dmesg | grep par and got the following references in the output that seemed like they might have to do with the parallel port: [ 14.169511] parport_pc 0000:03:07.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 [ 14.169516] PCI parallel port detected: 9710:9805, I/O at 0xce00(0xcd00), IRQ 21 [ 14.169577] parport0: PC-style at 0xce00 (0xcd00), irq 21, using FIFO [PCSPP,TRISTATE,COMPAT,ECP] [ 14.354254] lp0: using parport0 (interrupt-driven). [ 14.571358] ppdev: user-space parallel port driver [ 16.588304] type=1400 audit(1347226670.386:5): apparmor="STATUS" operation="profile_load" name="/usr/lib/cups/backend/cups-pdf" pid=964 comm="apparmor_parser" [ 16.588756] type=1400 audit(1347226670.386:6): apparmor="STATUS" operation="profile_load" name="/usr/sbin/cupsd" pid=964 comm="apparmor_parser" [ 16.673679] type=1400 audit(1347226670.470:7): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper" pid=1010 comm="apparmor_parser" [ 16.675252] type=1400 audit(1347226670.470:8): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/mission-control-5" pid=1014 comm="apparmor_parser" [ 16.675716] type=1400 audit(1347226670.470:9): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/telepathy-*" pid=1014 comm="apparmor_parser" [ 16.676636] type=1400 audit(1347226670.474:10): apparmor="STATUS" operation="profile_replace" name="/usr/lib/cups/backend/cups-pdf" pid=1015 comm="apparmor_parser" [ 16.677124] type=1400 audit(1347226670.474:11): apparmor="STATUS" operation="profile_replace" name="/usr/sbin/cupsd" pid=1015 comm="apparmor_parser" [ 1545.725328] parport0: ppdev0 forgot to release port I have no idea what any of that means, but the line “parport0: ppdev0 forgot to release port ” seems unusual. I was still unable to add a printer for my old clunker, so I tried the direct approach, typing echo “Hello” > /dev/lp0 and received a Permission denied message. I then tried echo “Hello” > /dev/parport0 which didn't give me any message at all, but still didn't print anything. Running the command sudo /usr/lib/cups/backend/parallel gives the following: direct parallel:/dev/lp0 "unknown" "LPT #1" "" "" Checking the permissions for /dev/parport0, Owner, Group, and Other are all set to read and write. crw-rw---- 1 root lp 6, 0 Sep 9 16:37 /dev/lp0 crw-rw-rw- 1 root lp 99, 0 Sep 9 16:37 /dev/parport0 The output of the command lpinfo -v includes the following line: direct parallel:/dev/lp0 I've read several web postings that seem to suggest this has been a problem for several years, but the bug reports were closed because there wasn't enough information to address the issue (shades of Microsoft!). Any suggestions as to what I might be missing here?

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