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  • Is it customary to write Java domain objects / data transfer objects with public member variables on mobile platforms?

    - by Sean Mickey
    We performed a code review recently of mobile application Java code that was developed by an outside contractor and noticed that all of the domain objects / data transfer objects are written in this style: public class Category { public String name; public int id; public String description; public int parentId; } public class EmergencyContact { public long id; public RelationshipType relationshipType; public String medicalProviderType; public Contact contact; public String otherPhone; public String notes; public PersonName personName; } Of course, these members are then accessed directly everywhere else in the code. When we asked about this, the developers told us that this is a customary performance enhancement design pattern that is used on mobile platforms, because mobile devices are resource-limited environments. It doesn't seem to make sense; accessing private members via public getters/setters doesn't seem like it could add much overhead. And the added benefits of encapsulation seem to outweigh the benefits of this coding style. Is this generally true? Is this something that is normally done on mobile platforms for the reasons given above? All feedback welcome and appreciated -

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  • Symfony 1.4/ Doctrine; n-m relation data cannot be accessed in template (indexSuccess)

    - by chandimak
    I have a database with 3 tables. It's a simple n-m relationship. Student, Course and StudentHasCourse to handle n-m relationship. I post the schema.yml for reference, but it would not be really necessary. Course: connection: doctrine tableName: course columns: id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false name: type: string(45) fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: StudentHasCourse: local: id foreign: course_id type: many Student: connection: doctrine tableName: student columns: id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false registration_details: type: string(45) fixed: false unsigned: false primary: false notnull: false autoincrement: false name: type: string(30) fixed: false unsigned: false primary: false notnull: false autoincrement: false relations: StudentHasCourse: local: id foreign: student_id type: many StudentHasCourse: connection: doctrine tableName: student_has_course columns: student_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false course_id: type: integer(4) fixed: false unsigned: false primary: true autoincrement: false result: type: string(1) fixed: true unsigned: false primary: false notnull: false autoincrement: false relations: Course: local: course_id foreign: id type: one Student: local: student_id foreign: id type: one Then, I get data from tables in executeIndex() from the following query. $q_info = Doctrine_Query::create() ->select('s.*, shc.*, c.*') ->from('Student s') ->leftJoin('s.StudentHasCourse shc') ->leftJoin('shc.Course c') ->where('c.id = 1'); $this->infos = $q_info->execute(); Then I access data by looping through in indexSuccess.php. But, in indexSuccess I can only access data from the table Student. <?php foreach ($infos as $info): ?> <?php echo $info->getId(); ?> <?php echo $info->getName(); ?> <?php endforeach; ?> I expected, that I could access StudentHasCourse data and Course data like the following. But, it generates an error. <?php echo $info->getStudentHasCourse()->getResult()?> <?php echo $info->getStudentHasCourse()->getCourse()->getName()?> The first statement gives a warning; Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'Doctrine_Collection' does not have a method 'getCourse' in D:\wamp\bin\php\php5.3.5\PEAR\pear\symfony\escaper\sfOutputEscaperObjectDecorator.class.php on line 64 And the second statement gives the above warning and the following error; Fatal error: Call to a member function getName() on a non-object in D:\wamp\www\sam\test_doc_1\apps\frontend\modules\registration\templates\indexSuccess.php on line 5 When I check the query from the Debug toolbar it appears as following and it gives all data I want. SELECT s.id AS s__id, s.registration_details AS s__registration_details, s.name AS s__name, s2.student_id AS s2__student_id, s2.course_id AS s2__course_id, s2.result AS s2__result, c.id AS c__id, c.name AS c__name FROM student s LEFT JOIN student_has_course s2 ON s.id = s2.student_id LEFT JOIN course c ON s2.course_id = c.id WHERE (c.id = 1) Though the question is short, as all the information mentioned it became so long. It's highly appreciated if someone can help me out to solve this. What I require is to access the data from StudentHasCourse and Course. If those data cannot be accessed by this design and this query, any other methodology is also appreciated.

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  • In an Entity/Component system, can component data be implemented as a simple array of key-value pairs? [on hold]

    - by 010110110101
    I'm trying to wrap my head around how to organize components in an Entity Component Systems once everything in the current scene/level is loaded in memory. (I'm a hobbyist BTW) Some people seem to implement the Entity as an object that contains a list of of "Component" objects. Components contain data organized as an array of key-value pairs. Where the value is serialized "somehow". (pseudocode is loosely in C# for brevity) class Entity { Guid _id; List<Component> _components; } class Component { List<ComponentAttributeValue> _attributes; } class ComponentAttributeValue { string AttributeName; object AttributeValue; } Others describe Components as an in-memory "table". An entity acquires the component by having its key placed in a table. The attributes of the component-entity instance are like the columns in a table class Renderable_Component { List<RenderableComponentAttributeValue> _entities; } class RenderableComponentAttributeValue { Guid entityId; matrix4 transformation; // other stuff for rendering // everything is strongly typed } Others describe this actually as a table. (and such tables sound like an EAV database schema BTW) (and the value is serialized "somehow") Render_Component_Table ---------------- Entity Id Attribute Name Attribute Value and when brought into running code: class Entity { Guid _id; Dictionary<string, object> _attributes; } My specific question is: Given various components, (Renderable, Positionable, Explodeable, Hideable, etc) and given that each component has an attribute with a particular name, (TRANSLATION_MATRIX, PARTICLE_EMISSION_VELOCITY, CAN_HIDE, FAVORITE_COLOR, etc) should: an entity contain a list of components where each component, in turn, has their own array of named attributes with values serialized somehow or should components exist as in-memory tables of entity references and associated with each "row" there are "columns" representing the attribute with values that are specific to each entity instance and are strongly typed or all attributes be stored in an entity as a singular array of named attributes with values serialized somehow (could have name collisions) or something else???

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  • What partition to use to keep data files in Ubuntu?

    - by Martin Lee
    I have been using Ubuntu for a few years and usually my partition set up was the following: Ext3 or Ext4 partition for the system itself (20 GB); A 10 GB swap partition; a big FAT32 partition to store movies, photos, work stuff, etc. (depends on the capacity of the disk, but usually it is what is left from Ext3+Swap, currently it is more than 200 GB). Does this setup sound right? I am considering to switching to one big Ext3 partition now, because the problem with Fat32 in Ubuntu has not gone anywhere: for example, right now I can access my 'big' partition with a 'Data' label only through /media/_themes?END. Pretty strange name for a partition, isn't it? some Linux software fail to read/write on this partition. For example, if I want to play around with rebar and build/make/compile things on this FAT32 partition, it will always complain about permissions and won't work (the same goes for many other kinds of software); it is not stable, I can not refer to some files on this FAT32 partition, because after the next reboot it will be called not '_themes?END', but something else. On the other side I usually begin to run out of space on the Ext3 partition after a few months of usage. So, the question is - what is the best setup of partitions for an Ubuntu system? Should a FAT32 partition be used at all?

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  • What scenarios are implementations of Object Management Group (OMG) Data Distribution Service best suited for?

    - by mindcrime
    I've always been a big fan of asynchronous messaging and pub/sub implementations, but coming from a Java background, I'm most familiar with using JMS based messaging systems, such as JBoss MQ, HornetQ, ActiveMQ, OpenMQ, etc. I've also loosely followed the discussion of AMQP. But I recently became aware of the Data Distribution Service Specification from the Object Management Group, and found there are a couple of open-source implementations: OpenSplice OpenDDS It sounds like this stuff is focused on the kind of high-volume scenarios one tends to associate with financial trading exchanges and what-not. My current interest is more along the lines of notifications related to activity stream processing (think Twitter / Facebook) and am wondering if the DDS servers are worth looking into further. Could anyone who has practical experience with this technology, and/or a deep understanding of it, comment on how useful it is, and what scenarios it is best suited for? How does it stack up against more "traditional" JMS servers, and/or AMQP (or even STOMP or OpenWire, etc?) Edit: FWIW, I found some information at this StackOverflow thread. Not a complete answer, but anybody else finding this question might also find that thread useful, hence the added link.

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  • How can I set up FakeRAID/SoftRAID using mdadm without losing data?

    - by Danatela
    There is RAID0 of 2 drives connected through Silicon Image 3132 SATA SoftRAID controller. Under Windows it was partitioned as one dynamic GPT-disk having 4 TB NTFS volume. There is a lot of music and movies on the drive. I'm trying to get him to be seen under Ubuntu as a single disk, not as 2 by 2 terabytes. I tried to read it through dmraid, had no success, it is not displayed in /dev/mapper. Also tried to configure the kernel, but did not find anything suspicious, the driver for my controller was on. There is also a driver from the manufacturer, but it is only available for RHEL and SLES. Here it's reported that SoftRAID is supported by the kernel, but apparently not completely. If I thrust drives in the AMD controller, built into the motherboard, the drive is seen as a single, but the data is lost. I know about mdadm that it is able to ditch all the information on the disks. So, is it possible to somehow create an array without actually recording information on used drives and to make the system correctly identify sections on it later? Information about the array: /dev/sdf - Disk 0 /dev/sdg - Disk 1 Array type: Stripe Block Size: 64KB Also, a device /dev/md1 is created using command mknod /dev/md1 b 9 1

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  • What data should be cached in a multiplayer server, relative to AI and players?

    - by DevilWithin
    In a virtual place, fully network driven, with an arbitrary number of players and an arbitrary number of enemies, what data should be cached in the server memory, in order to optimize smooth AI simulation? Trying to explain, lets say player A sees player B to E, and enemy A to G. Each of those players, see player A, but not necessarily each other. Same applies to enemies. Think of this question from a topdown perspective please. In many cases, for example, when a player shoots his gun, the server handles the sound as a radial "signal" that every other entity within reach "hear" and react upon. Doing these searches all the time for a whole area, containing possibly a lot of unrelated players and enemies, seems to be an issue, when the budget for each AI agent is so small. Should every entity cache whatever enters and exits from its radius of awareness? Is there a great way to trace the entities close by without flooding the memory with such caches? What about other AI related problems that may arise, after assuming the previous one works well? We're talking about environments with possibly hundreds of enemies, a swarm.

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  • What is an effective way to convert a shared memory-mapped system to another data access model?

    - by Rob Jones
    I have a code base that is designed around shared memory. Each process that needs to access the memory maps it into its own address space. The data structures in the shared memory are directly accessed, that is, there is no API. For example: Assume the following: typedef struct { int x; int y; struct { int a; int b; } z; } myStruct; myStruct s; Then a process might access this structure as: myStruct *s = mapGlobalMem(); And use it as: int tmpX = s->x; The majority of the information in the global structure is configuration information that is set once and read many times. I would like to store this information in a database and develop an API to access the database. The problem is, these references are sprinkled throughout the code. I need a way to parse the code and identify global structure references that will need to be refactored. I've looked into using ANTLR to create a parser that will identify references to a small set of structures and enter them into a custom symbol table. I could then use this symbol table to identify which source files need to be refactored. It looks like a promising approach. What other approaches are there? Of course, I'm looking for a programmatic approach. There are far too many source files to examine each one visually. This is all ordinary ANSI C. Nothing else.

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  • webhost4life, please give me, my data back. My website will not work without the database.

    - by Shervin Shakibi
    I have about 4 or 5 accounts with WebHost4life.com, these are all my customers that based on my recommendation have been hosting with webhost4life.com. A few days ago for some reason they decided to migrate one of these accounts to a new server. They moved everything created a new database on the new server but the new database is empty. after spending hours with Tech support they acknowledged the problem and assured me it will take up to an hour or two and my database will be populated with the data. this was about 7 hours ago. Oh by the way I pay extra for the backup plan and yes you guessed it, none of my backups are there. Needless to say I’m very scared and disappointed. No one is responding to my emails  or phone calls. After searching the web, I found out, this has happened before, in some cases it took them days to fix the problem and many never got it resolved and switched hosting companies, I would love to do that but I need my 2 GB database before I start shopping around for a new hosting company. Stay away from Webhost4life.

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  • I need an approach to the problem of preventing inserting duplicate records into the database

    - by Maurice
    Apologies is this question is asked on the incorrect "stack" A webservice that I call returns a list of data. The data from the webservice is updated periodically, so a call to the webservice done in one hour could return the same data as a call done in an hour. Also, the data is returned based on a start and end date. We have multiple users that can run the webservice search, and duplicate data is most likely to be returned (especially for historical data). However I don't want to insert this duplicate data in the database. I've created a db table in which the data is stored (most important columns are) Id int autoincrement PK Date date not null --The date to which the data set belongs. LastUpdate date not null --The date the data set was last updated. UserName varchar(50) --The name of the user doing the search. I use sql server 2008 express with c# 4.0 and visual studio 2010. Entity Framework is used as the ORM. If stored procedures could be avoided in the proposed solution, then that will be a plus. Another way of looking interpreting what I'm asking a solution for is as follows: I have a million unique records in my table. A user does a new search. The search results from the user contains around 300k of the data that is already in the db. An efficient solution to finding an inserting only the unique records is needed.

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  • OpenGL - Rendering from part of an index and vertex array depending on an element count

    - by user1423893
    I'm currently drawing my shapes as lines by using a VAO and then assigning the dynamic vertices and indices each frame. // Bind VAO glBindVertexArray(m_vao); // Update the vertex buffer with the new data (Copy data into the vertex buffer object) glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(VertexPosition), m_vertices.data(), GL_DYNAMIC_DRAW); // Update the index buffer with the new data (Copy data into the index buffer object) glBufferData(GL_ELEMENT_ARRAY_BUFFER, numIndices * sizeof(unsigned short), indices.data(), GL_DYNAMIC_DRAW); glDrawElements(GL_LINES, numIndices, GL_UNSIGNED_SHORT, BUFFER_OFFSET(0)); // Unbind VAO glBindVertexArray(0); What I would like to do is draw the lines using only part of the data stored in the index and vertex buffer objects. The vertex buffer has its vertices set from an array of defined maximum size: std::array<VertexPosition, maxVertices> m_vertices; The index buffer has its elements set from an array of defined maximum size: std::array<unsigned short, maxIndices> indices = { 0 }; A running total is kept of the number of vertices and indices needed for each draw call numVertices numIndices Can I not specify that the buffer data contain the entire array and only read from part of it when drawing? For example using the vertex buffer object glBufferData(GL_ARRAY_BUFFER, numVertices * sizeof(VertexPosition), m_vertices.data(), GL_DYNAMIC_DRAW); m_vertices.data() = Entire array is stored numVertices * sizeof(VertexPosition) = Amount of data to read from the entire array Is this not the correct way to approach this? I do not wish to use std::vector if possible.

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  • Stumbling Through: Visual Studio 2010 (Part IV)

    So finally we get to the fun part the fruits of all of our middle-tier/back end labors of generating classes to interface with an XML data source that the previous posts were about can now be presented quickly and easily to an end user.  I think.  Well see.  Well be using a WPF window to display all of our various MFL information that weve collected in the two XML files, and well provide a means of adding, updating and deleting each of these entities using as little code as possible.  Additionally, I would like to dig into the performance of this solution as well as the flexibility of it if were were to modify the underlying XML schema.  So first things first, lets create a WPF project and include our xml data in a data folder within.  On the main window, well drag out the following controls: A combo box to contain all of the teams A list box to show the players of the selected team, along with add/delete player buttons A text box tied to the selected players name, with a save button to save any changes made to the player name A combo box of all the available positions, tied to the currently selected players position A data grid tied to the statistics of the currently selected player, with add/delete statistic buttons This monstrosity of a form and its associated project will look like this (dont forget to reference the DataFoundation project from the Presentation project): To get to the visual data binding, as we learned in a previous post, you have to first make sure the project containing your bindable classes is compiled.  Do so, and then open the Data Sources pane to add a reference to the Teams and Positions classes in the DataFoundation project: Why only Team and Position?  Well, we will get to Players from Teams, and Statistics from Players so no need to make an interface for them as well see in a second.  As for Positions, well need a way to bind the dropdown to ALL positions they dont appear underneath any of the other classes so we need to reference it directly.  After adding these guys, expand every node in your Data Sources pane and see how the Team node allows you to drill into Players and then Statistics.  This is why there was no need to bring in a reference to those classes for the UI we are designing: Now for the seriously hard work of binding all of our controls to the correct data sources.  Drag the following items from the Data Sources pane to the specified control on the window design canvas: Team.Name > Teams combo box Team.Players.Name > Players list box Team.Players.Name > Player name text box Team.Players.Statistics > Statistics data grid Position.Name > Positions combo box That is it!  Really?  Well, no, not really there is one caveat here in that the Positions combo box is not bound the selected players position.  To do so, we will apply a binding to the position combo boxs SelectedValue to point to the current players PositionId value: That should do the trick now, all we need to worry about is loading the actual data.  Sadly, it appears as if we will need to drop to code in order to invoke our IO methods to load all teams and positions.  At least Visual Studio kindly created the stubs for us to do so, ultimately the code should look like this: Note the weirdness with the InitializeDataFiles call that is my current means of telling an IO where to load the data for each of the entities.  I havent thought of a more intuitive way than that yet, but do note that all data is loaded from Teams.xml besides for positions, which is loaded from Lookups.xml.   I think that may be all we need to do to at least load all of the data, lets run it and see: Yay!  All of our glorious data is being displayed!  Er, wait, whats up with the position dropdown?  Why is it red?  Lets select the RB and see if everything updates: Crap, the position didnt update to reflect the selected player, but everything else did.  Where did we go wrong in binding the position to the selected player?  Thinking about it a bit and comparing it to how traditional data binding works, I realize that we never set the value member (or some similar property) to tell the control to join the Id of the source (positions) to the position Id of the player.  I dont see a similar property to that on the combo box control, but I do see a property named SelectedValuePath that might be it, so I set it to Id and run the app again: Hey, all right!  No red box around the positions combo box.  Unfortunately, selecting the RB does not update the dropdown to point to Runningback.  Hmmm.  Now what could it be?  Maybe the problem is that we are loading teams before we are loading positions, so when it binds position Id, all of the positions arent loaded yet.  I went to the code behind and switched things so position loads first and no dice.  Same result when I run.  Why?  WHY?  Ok, ok, calm down, take a deep breath.  Get something with caffeine or sugar (preferably both) and think rationally. Ok, gigantic chocolate chip cookie and a mountain dew chaser have never let me down in the past, so dont fail me now!  Ah ha!  of course!  I didnt even have to finish the mountain dew and I think Ive got it:  Data Context.  By default, when setting on the selected value binding for the dropdown, the data context was list_team.  I dont even know what the heck list_team is, we want it to be bound to our team players view source resource instead, like this: Running it now and selecting the various players: Done and done.  Everything read and bound, thank you caffeine and sugar!  Oh, and thank you Visual Studio 2010.  Lets wire up some of those buttons now There has got to be a better way to do this, but it works for now.  What the add player button does is add a new player object to the currently selected team.  Unfortunately, I couldnt get the new object to automatically show up in the players list (something about not using an observable collection gotta look into this) so I just save the change immediately and reload the screen.  Terrible, but it works: Lets go after something easier:  The save button.  By default, as we type in new text for the players name, it is showing up in the list box as updated.  Cool!  Why couldnt my add new player logic do that?  Anyway, the save button should be as simple as invoking MFL.IO.Save for the selected player, like this: MFL.IO.Save((MFL.Player)lbTeamPlayers.SelectedItem, true); Surprisingly, that worked on the first try.  Lets see if we get as lucky with the Delete player button: MFL.IO.Delete((MFL.Player)lbTeamPlayers.SelectedItem); Refresh(); Note the use of the Refresh method again I cant seem to figure out why updates to the underlying data source are immediately reflected, but adds and deletes are not.  That is a problem for another day, and again my hunch is that I should be binding to something more complex than IEnumerable (like observable collection). Now that an example of the basic CRUD methods are wired up, I want to quickly investigate the performance of this beast.  Im going to make a special button to add 30 teams, each with 50 players and 10 seasons worth of stats.  If my math is right, that will end up with 15000 rows of data, a pretty hefty amount for an XML file.  The save of all this new data took a little over a minute, but that is acceptable because we wouldnt typically be saving batches of 15k records, and the resulting XML file size is a little over a megabyte.  Not huge, but big enough to see some read performance numbers or so I thought.  It reads this file and renders the first team in under a second.  That is unbelievable, but we are lazy loading and the file really wasnt that big.  I will increase it to 50 teams with 100 players and 20 seasons each - 100,000 rows.  It took a year and a half to save all of that data, and resulted in an 8 megabyte file.  Seriously, if you are loading XML files this large, get a freaking database!  Despite this, it STILL takes under a second to load and render the first team, which is interesting mostly because I thought that it was loading that entire 8 MB XML file behind the scenes.  I have to say that I am quite impressed with the performance of the LINQ to XML approach, particularly since I took no efforts to optimize any of this code and was fairly new to the concept from the start.  There might be some merit to this little project after all Look out SQL Server and Oracle, use XML files instead!  Next up, I am going to completely pull the rug out from under the UI and change a number of entities in our model.  How well will the code be regenerated?  How much effort will be required to tie things back together in the UI?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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  • Who should have full visibility of all (non-data) requirements information?

    - by ebyrob
    I work at a smallish mid-size company where requirements are sometimes nothing more than an email or brief meeting with a subject matter manager requiring some new feature. Should a programmer working on a feature reasonably expect to have access to such "request emails" and other requirements information? Is it more appropriate for a "program manager" (PGM) to rewrite all requirements before sharing with programmers? The company is not technology-centric and has between 50 and 250 employees. (fewer than 10 programmers in sum) Our project management "software" consists of a "TODO.txt" checked into source control in "/doc/". Note: This is nothing to do with "sensitive data access". Unless a particular subject matter manager's style of email correspondence is top secret. Given the suggested duplicate, perhaps this could be a turf war, as the PGM would like to specify HOW. Whereas WHY is absent and WHAT is muddled by the time it gets through to the programmer(s)... Basically. Should specification be transparent to programmers? Perhaps a history of requirements might exist. Shouldn't a programmer be able to see that history of reqs if/when they can tell something is hinky in the spec? This isn't a question about organizing requirements. It is a question about WHO should have full VISIBILITY of requirements. I'd propose it should be ALL STAKEHOLDERS. Please point out where I'm wrong here.

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  • Would this data requirement suit a Document -Oriented database?

    - by codecowboy
    I have a requirement to allow users to fill in journal/diary entries per day. I want to provide a handful of known journal templates with x columns to fill in. An example might be a thought diary; a user has to record a thought in one column, describe the situation, rate how they felt etc. The other requirement is that a user should be able to create their own diary templates. They might have a need for a 10 column diary entry per day and might need to rate some aspect out of 50 instead of 10. In an RDBMS, I can see this getting quite complicated. I could have individual tables for my known templates as the fields will be fixed. But for custom diary templates I imagine I would would need a table storing custom_field_types (the diary columns), a table storing entries referencing their field types (custom_entries) and then a third custom_diary table which would store rows matching custom_entries to diaries. Leaving performance / scaling aside, would it be any simpler or make more sense to use a document oriented database like MongoDB to store this data? This is for a web application which might later need an API for mobile devices.

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  • Entity Framework Code-First, OData & Windows Phone Client

    - by Jon Galloway
    Entity Framework Code-First is the coolest thing since sliced bread, Windows  Phone is the hottest thing since Tickle-Me-Elmo and OData is just too great to ignore. As part of the Full Stack project, we wanted to put them together, which turns out to be pretty easy… once you know how.   EF Code-First CTP5 is available now and there should be very few breaking changes in the release edition, which is due early in 2011.  Note: EF Code-First evolved rapidly and many of the existing documents and blog posts which were written with earlier versions, may now be obsolete or at least misleading.   Code-First? With traditional Entity Framework you start with a database and from that you generate “entities” – classes that bridge between the relational database and your object oriented program. With Code-First (Magic-Unicorn) (see Hanselman’s write up and this later write up by Scott Guthrie) the Entity Framework looks at classes you created and says “if I had created these classes, the database would have to have looked like this…” and creates the database for you! By deriving your entity collections from DbSet and exposing them via a class that derives from DbContext, you "turn on" database backing for your POCO with a minimum of code and no hidden designer or configuration files. POCO == Plain Old CLR Objects Your entity objects can be used throughout your applications - in web applications, console applications, Silverlight and Windows Phone applications, etc. In our case, we'll want to read and update data from a Windows Phone client application, so we'll expose the entities through a DataService and hook the Windows Phone client application to that data via proxies.  Piece of Pie.  Easy as cake. The Demo Architecture To see this at work, we’ll create an ASP.NET/MVC application which will act as the host for our Data Service.  We’ll create an incredibly simple data layer using EF Code-First on top of SQLCE4 and we’ll expose the data in a WCF Data Service using the oData protocol.  Our Windows Phone 7 client will instantiate  the data context via a URI and load the data asynchronously. Setting up the Server project with MVC 3, EF Code First, and SQL CE 4 Create a new application of type ASP.NET MVC 3 and name it DeadSimpleServer.  We need to add the latest SQLCE4 and Entity Framework Code First CTP's to our project. Fortunately, NuGet makes that really easy. Open the Package Manager Console (View / Other Windows / Package Manager Console) and type in "Install-Package EFCodeFirst.SqlServerCompact" at the PM> command prompt. Since NuGet handles dependencies for you, you'll see that it installs everything you need to use Entity Framework Code First in your project. PM> install-package EFCodeFirst.SqlServerCompact 'SQLCE (= 4.0.8435.1)' not installed. Attempting to retrieve dependency from source... Done 'EFCodeFirst (= 0.8)' not installed. Attempting to retrieve dependency from source... Done 'WebActivator (= 1.0.0.0)' not installed. Attempting to retrieve dependency from source... Done You are downloading SQLCE from Microsoft, the license agreement to which is available at http://173.203.67.148/licenses/SQLCE/EULA_ENU.rtf. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'SQLCE 4.0.8435.1' You are downloading EFCodeFirst from Microsoft, the license agreement to which is available at http://go.microsoft.com/fwlink/?LinkID=206497. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'EFCodeFirst 0.8' Successfully installed 'WebActivator 1.0.0.0' You are downloading EFCodeFirst.SqlServerCompact from Microsoft, the license agreement to which is available at http://173.203.67.148/licenses/SQLCE/EULA_ENU.rtf. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'EFCodeFirst.SqlServerCompact 0.8' Successfully added 'SQLCE 4.0.8435.1' to EfCodeFirst-CTP5 Successfully added 'EFCodeFirst 0.8' to EfCodeFirst-CTP5 Successfully added 'WebActivator 1.0.0.0' to EfCodeFirst-CTP5 Successfully added 'EFCodeFirst.SqlServerCompact 0.8' to EfCodeFirst-CTP5 Note: We're using SQLCE 4 with Entity Framework here because they work really well together from a development scenario, but you can of course use Entity Framework Code First with other databases supported by Entity framework. Creating The Model using EF Code First Now we can create our model class. Right-click the Models folder and select Add/Class. Name the Class Person.cs and add the following code: using System.Data.Entity; namespace DeadSimpleServer.Models { public class Person { public int ID { get; set; } public string Name { get; set; } } public class PersonContext : DbContext { public DbSet<Person> People { get; set; } } } Notice that the entity class Person has no special interfaces or base class. There's nothing special needed to make it work - it's just a POCO. The context we'll use to access the entities in the application is called PersonContext, but you could name it anything you wanted. The important thing is that it inherits DbContext and contains one or more DbSet which holds our entity collections. Adding Seed Data We need some testing data to expose from our service. The simplest way to get that into our database is to modify the CreateCeDatabaseIfNotExists class in AppStart_SQLCEEntityFramework.cs by adding some seed data to the Seed method: protected virtual void Seed( TContext context ) { var personContext = context as PersonContext; personContext.People.Add( new Person { ID = 1, Name = "George Washington" } ); personContext.People.Add( new Person { ID = 2, Name = "John Adams" } ); personContext.People.Add( new Person { ID = 3, Name = "Thomas Jefferson" } ); personContext.SaveChanges(); } The CreateCeDatabaseIfNotExists class name is pretty self-explanatory - when our DbContext is accessed and the database isn't found, a new one will be created and populated with the data in the Seed method. There's one more step to make that work - we need to uncomment a line in the Start method at the top of of the AppStart_SQLCEEntityFramework class and set the context name, as shown here, public static class AppStart_SQLCEEntityFramework { public static void Start() { DbDatabase.DefaultConnectionFactory = new SqlCeConnectionFactory("System.Data.SqlServerCe.4.0"); // Sets the default database initialization code for working with Sql Server Compact databases // Uncomment this line and replace CONTEXT_NAME with the name of your DbContext if you are // using your DbContext to create and manage your database DbDatabase.SetInitializer(new CreateCeDatabaseIfNotExists<PersonContext>()); } } Now our database and entity framework are set up, so we can expose data via WCF Data Services. Note: This is a bare-bones implementation with no administration screens. If you'd like to see how those are added, check out The Full Stack screencast series. Creating the oData Service using WCF Data Services Add a new WCF Data Service to the project (right-click the project / Add New Item / Web / WCF Data Service). We’ll be exposing all the data as read/write.  Remember to reconfigure to control and minimize access as appropriate for your own application. Open the code behind for your service. In our case, the service was called PersonTestDataService.svc so the code behind class file is PersonTestDataService.svc.cs. using System.Data.Services; using System.Data.Services.Common; using System.ServiceModel; using DeadSimpleServer.Models; namespace DeadSimpleServer { [ServiceBehavior( IncludeExceptionDetailInFaults = true )] public class PersonTestDataService : DataService<PersonContext> { // This method is called only once to initialize service-wide policies. public static void InitializeService( DataServiceConfiguration config ) { config.SetEntitySetAccessRule( "*", EntitySetRights.All ); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; config.UseVerboseErrors = true; } } } We're enabling a few additional settings to make it easier to debug if you run into trouble. The ServiceBehavior attribute is set to include exception details in faults, and we're using verbose errors. You can remove both of these when your service is working, as your public production service shouldn't be revealing exception information. You can view the output of the service by running the application and browsing to http://localhost:[portnumber]/PersonTestDataService.svc/: <service xml:base="http://localhost:49786/PersonTestDataService.svc/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:app="http://www.w3.org/2007/app" xmlns="http://www.w3.org/2007/app"> <workspace> <atom:title>Default</atom:title> <collection href="People"> <atom:title>People</atom:title> </collection> </workspace> </service> This indicates that the service exposes one collection, which is accessible by browsing to http://localhost:[portnumber]/PersonTestDataService.svc/People <?xml version="1.0" encoding="iso-8859-1" standalone="yes"?> <feed xml:base=http://localhost:49786/PersonTestDataService.svc/ xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <title type="text">People</title> <id>http://localhost:49786/PersonTestDataService.svc/People</id> <updated>2010-12-29T01:01:50Z</updated> <link rel="self" title="People" href="People" /> <entry> <id>http://localhost:49786/PersonTestDataService.svc/People(1)</id> <title type="text"></title> <updated>2010-12-29T01:01:50Z</updated> <author> <name /> </author> <link rel="edit" title="Person" href="People(1)" /> <category term="DeadSimpleServer.Models.Person" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:ID m:type="Edm.Int32">1</d:ID> <d:Name>George Washington</d:Name> </m:properties> </content> </entry> <entry> ... </entry> </feed> Let's recap what we've done so far. But enough with services and XML - let's get this into our Windows Phone client application. Creating the DataServiceContext for the Client Use the latest DataSvcUtil.exe from http://odata.codeplex.com. As of today, that's in this download: http://odata.codeplex.com/releases/view/54698 You need to run it with a few options: /uri - This will point to the service URI. In this case, it's http://localhost:59342/PersonTestDataService.svc  Pick up the port number from your running server (e.g., the server formerly known as Cassini). /out - This is the DataServiceContext class that will be generated. You can name it whatever you'd like. /Version - should be set to 2.0 /DataServiceCollection - Include this flag to generate collections derived from the DataServiceCollection base, which brings in all the ObservableCollection goodness that handles your INotifyPropertyChanged events for you. Here's the console session from when we ran it: <ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding}" SelectionChanged="MainListBox_SelectionChanged"> Next, to keep things simple, change the Binding on the two TextBlocks within the DataTemplate to Name and ID, <ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding}" SelectionChanged="MainListBox_SelectionChanged"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Margin="0,0,0,17" Width="432"> <TextBlock Text="{Binding Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" /> <TextBlock Text="{Binding ID}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Getting The Context In the code-behind you’ll first declare a member variable to hold the context from the Entity Framework. This is named using convention over configuration. The db type is Person and the context is of type PersonContext, You initialize it by providing the URI, in this case using the URL obtained from the Cassini web server, PersonContext context = new PersonContext( new Uri( "http://localhost:49786/PersonTestDataService.svc/" ) ); Create a second member variable of type DataServiceCollection<Person> but do not initialize it, DataServiceCollection<Person> people; In the constructor you’ll initialize the DataServiceCollection using the PersonContext, public MainPage() { InitializeComponent(); people = new DataServiceCollection<Person>( context ); Finally, you’ll load the people collection using the LoadAsync method, passing in the fully specified URI for the People collection in the web service, people.LoadAsync( new Uri( "http://localhost:49786/PersonTestDataService.svc/People" ) ); Note that this method runs asynchronously and when it is finished the people  collection is already populated. Thus, since we didn’t need or want to override any of the behavior we don’t implement the LoadCompleted. You can use the LoadCompleted event if you need to do any other UI updates, but you don't need to. The final code is as shown below: using System; using System.Data.Services.Client; using System.Windows; using System.Windows.Controls; using DeadSimpleServer.Models; using Microsoft.Phone.Controls; namespace WindowsPhoneODataTest { public partial class MainPage : PhoneApplicationPage { PersonContext context = new PersonContext( new Uri( "http://localhost:49786/PersonTestDataService.svc/" ) ); DataServiceCollection<Person> people; // Constructor public MainPage() { InitializeComponent(); // Set the data context of the listbox control to the sample data // DataContext = App.ViewModel; people = new DataServiceCollection<Person>( context ); people.LoadAsync( new Uri( "http://localhost:49786/PersonTestDataService.svc/People" ) ); DataContext = people; this.Loaded += new RoutedEventHandler( MainPage_Loaded ); } // Handle selection changed on ListBox private void MainListBox_SelectionChanged( object sender, SelectionChangedEventArgs e ) { // If selected index is -1 (no selection) do nothing if ( MainListBox.SelectedIndex == -1 ) return; // Navigate to the new page NavigationService.Navigate( new Uri( "/DetailsPage.xaml?selectedItem=" + MainListBox.SelectedIndex, UriKind.Relative ) ); // Reset selected index to -1 (no selection) MainListBox.SelectedIndex = -1; } // Load data for the ViewModel Items private void MainPage_Loaded( object sender, RoutedEventArgs e ) { if ( !App.ViewModel.IsDataLoaded ) { App.ViewModel.LoadData(); } } } } With people populated we can set it as the DataContext and run the application; you’ll find that the Name and ID are displayed in the list on the Mainpage. Here's how the pieces in the client fit together: Complete source code available here

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  • Old operational master still thinks it is the "one"

    - by Doug
    Hi there, I have a domain with 3 AD servers for now i'll just call them: AD01 (Win 2008 GC, Operations master) AD02 (Win 2008 GC) AD03 (Win 2003 GC) A couple of months there was some hardware issues with AD01 so the operations master, PDC and Infrastructure Master was moved to AD02. All machines where on while this was happening. AD01 (Win 2008 GC) AD02 (Win 2008 GC, Operations master) AD03 (Win 2003 GC) AD01 was then shutdown for a month. Upon starting this machine up with replaced hardware (NIC and RAID card) i now have a weird problem. AD01 Thinks it is operations master still in AD on the local box AD02 & AD03 Thinks AD02 is operations master in AD on both boxes When running DCDIAG on AD01 i get a number of issues (listed below) When running "dcdiag /test:advertising" on AD01: Doing primary tests Testing server: Default-First-Site-Name\AD01 Starting test: Advertising Warning: DsGetDcName returned information for \\ad02.domain.local, when we were trying to reach AD01. SERVER IS NOT RESPONDING or IS NOT CONSIDERED SUITABLE. ......................... AD01 failed test Advertising Running partition tests on : ForestDnsZones Running partition tests on : DomainDnsZones Running partition tests on : Schema Running partition tests on : Configuration Running partition tests on : domain Running enterprise tests on : domain.local When running "dcdiag" on AD01 i get the following errors (excerpt of the Final output): Testing server: Default-First-Site-Name\AD01 Starting test: Advertising Warning: DsGetDcName returned information for \\ad02.domain.local, when we were trying to reach AD01. SERVER IS NOT RESPONDING or IS NOT CONSIDERED SUITABLE. ......................... AD01 failed test Advertising Starting test: FrsEvent There are warning or error events within the last 24 hours after the SYSVOL has been shared. Failing SYSVOL replication problems may cause Group Policy problems. Starting test: NCSecDesc Error NT AUTHORITY\ENTERPRISE DOMAIN CONTROLLERS doesn't have Replicating Directory Changes In Filtered Set access rights for the naming context: DC=ForestDnsZones,DC=domain,DC=local Error NT AUTHORITY\ENTERPRISE DOMAIN CONTROLLERS doesn't have Replicating Directory Changes In Filtered Set access rights for the naming context: DC=DomainDnsZones,DC=domain,DC=local Starting test: Replications [Replications Check,Replications Check] Inbound replication is disabled. To correct, run "repadmin /options AD01 -DISABLE_INBOUND_REPL" [Replications Check,AD01] Outbound replication is disabled. To correct, run "repadmin /options AD01 -DISABLE_OUTBOUND_REPL" So the problem appeasr to be that when i moved the operations master, AD01 never got the memo, and now that it's started up, all the other AD servers don't think its the boss anymore when it trys to replicate etc. So i really need to manually update AD01 so that it knows who the operations master, instrastructure and PDC is - but i'm not having any luck I've been googling for nearly a day and all solutions lead to "the cake is a lie" Your ninja skills will be greatly appreciated

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  • Partner Webcast – Oracle Coherence Applications on WebLogic 12c Grid - 21st Nov 2013

    - by Thanos Terentes Printzios
    Oracle Coherence is the industry leading in-memory data grid solution that enables organizations to predictably scale mission-critical applications by providing fast access to frequently used data. As data volumes and customer expectations increase, driven by the “internet of things”, social, mobile, cloud and always-connected devices, so does the need to handle more data in real-time, offload over-burdened shared data services and provide availability guarantees. The latest release of Oracle Coherence 12c comes with great improvements in ease of use, integration and RASP (Reliability, Availability, Scalability, and Performance) areas. In addition it features an innovating approach to build and deploy Coherence Application as an integral part of typical JEE Enterprise Application. Coherence GAR archives and Coherence Managed Servers are now first-class citizens of all JEE applications and Oracle WebLogic domains respectively. That enables even easier development, deployment and management of complex multi-tier enterprise applications powered by data grid rich features. Oracle Coherence 12c makes your solution ready for the future of big data and always-on-line world. This webcast is focused on demonstrating How to create a Coherence Application using Oracle Enterprise Pack for Eclipse 12.1.2.1.1 (Kepler release). How to package the application in form of GAR archive inside the EAR deployable application. How to deploy the application to multi-tier WebLogic clusters. How to define and configure the WebLogic domain for the tiered clusters hosting both data grid and client JEE applications.  Finally we will expose the data in grid to external systems using REST services and create a simple web interface to the underlying data using Oracle ADF Faces components. Join us on this technology webcast, to find out more about how Oracle Cloud Application Frameworks brings together the key industry leading technologies of Oracle Coherence and Weblogic 12c, delivering next-generation applications. Agenda: Introduction to Oracle Coherence What's new in 12c release POF annotations Live Events Elastic Data (Flash storage support) Managed Coherence Servers for Oracle WebLogic Coherence Applications (Grid Archive) Live Demonstration Creating and configuring Coherence Servers forming the data tier cluster Creating a simple Coherence Grid Application in Eclipse Adding REST support and creating simple ADF Faces client application Deploying the grid and client applications to separate tiers in WebLogic topology HA capabilities of the data tier Summary - Q&A Delivery Format This FREE online LIVE eSeminar will be delivered over the Web. Registrations received less than 24hours prior to start time may not receive confirmation to attend. Duration: 1 hour REGISTER NOW For any questions please contact us at partner.imc-AT-beehiveonline.oracle-DOT-com Stay Connected Oracle Newsletters

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  • Calculating the Size (in Bytes and MB) of a Oracle Coherence Cache

    - by Ricardo Ferreira
    The concept and usage of data grids are becoming very popular in this days since this type of technology are evolving very fast with some cool lead products like Oracle Coherence. Once for a while, developers need an programmatic way to calculate the total size of a specific cache that are residing in the data grid. In this post, I will show how to accomplish this using Oracle Coherence API. This example has been tested with 3.6, 3.7 and 3.7.1 versions of Oracle Coherence. To start the development of this example, you need to create a POJO ("Plain Old Java Object") that represents a data structure that will hold user data. This data structure will also create an internal fat so I call that should increase considerably the size of each instance in the heap memory. Create a Java class named "Person" as shown in the listing below. package com.oracle.coherence.domain; import java.io.Serializable; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Random; @SuppressWarnings("serial") public class Person implements Serializable { private String firstName; private String lastName; private List<Object> fat; private String email; public Person() { generateFat(); } public Person(String firstName, String lastName, String email) { setFirstName(firstName); setLastName(lastName); setEmail(email); generateFat(); } private void generateFat() { fat = new ArrayList<Object>(); Random random = new Random(); for (int i = 0; i < random.nextInt(18000); i++) { HashMap<Long, Double> internalFat = new HashMap<Long, Double>(); for (int j = 0; j < random.nextInt(10000); j++) { internalFat.put(random.nextLong(), random.nextDouble()); } fat.add(internalFat); } } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } } Now let's create a Java program that will start a data grid into Coherence and will create a cache named "People", that will hold people instances with sequential integer keys. Each person created in this program will trigger the execution of a custom constructor created in the People class that instantiates an internal fat (the random amount of data generated to increase the size of the object) for each person. Create a Java class named "CreatePeopleCacheAndPopulateWithData" as shown in the listing below. package com.oracle.coherence.demo; import com.oracle.coherence.domain.Person; import com.tangosol.net.CacheFactory; import com.tangosol.net.NamedCache; public class CreatePeopleCacheAndPopulateWithData { public static void main(String[] args) { // Asks Coherence for a new cache named "People"... NamedCache people = CacheFactory.getCache("People"); // Creates three people that will be putted into the data grid. Each person // generates an internal fat that should increase its size in terms of bytes... Person pessoa1 = new Person("Ricardo", "Ferreira", "[email protected]"); Person pessoa2 = new Person("Vitor", "Ferreira", "[email protected]"); Person pessoa3 = new Person("Vivian", "Ferreira", "[email protected]"); // Insert three people at the data grid... people.put(1, pessoa1); people.put(2, pessoa2); people.put(3, pessoa3); // Waits for 5 minutes until the user runs the Java program // that calculates the total size of the people cache... try { System.out.println("---> Waiting for 5 minutes for the cache size calculation..."); Thread.sleep(300000); } catch (InterruptedException ie) { ie.printStackTrace(); } } } Finally, let's create a Java program that, using the Coherence API and JMX, will calculate the total size of each cache that the data grid is currently managing. The approach used in this example was retrieve every cache that the data grid are currently managing, but if you are interested on an specific cache, the same approach can be used, you should only filter witch cache will be looked for. Create a Java class named "CalculateTheSizeOfPeopleCache" as shown in the listing below. package com.oracle.coherence.demo; import java.text.DecimalFormat; import java.util.Map; import java.util.Set; import java.util.TreeMap; import javax.management.MBeanServer; import javax.management.MBeanServerFactory; import javax.management.ObjectName; import com.tangosol.net.CacheFactory; public class CalculateTheSizeOfPeopleCache { @SuppressWarnings({ "unchecked", "rawtypes" }) private void run() throws Exception { // Enable JMX support in this Coherence data grid session... System.setProperty("tangosol.coherence.management", "all"); // Create a sample cache just to access the data grid... CacheFactory.getCache(MBeanServerFactory.class.getName()); // Gets the JMX server from Coherence data grid... MBeanServer jmxServer = getJMXServer(); // Creates a internal data structure that would maintain // the statistics from each cache in the data grid... Map cacheList = new TreeMap(); Set jmxObjectList = jmxServer.queryNames(new ObjectName("Coherence:type=Cache,*"), null); for (Object jmxObject : jmxObjectList) { ObjectName jmxObjectName = (ObjectName) jmxObject; String cacheName = jmxObjectName.getKeyProperty("name"); if (cacheName.equals(MBeanServerFactory.class.getName())) { continue; } else { cacheList.put(cacheName, new Statistics(cacheName)); } } // Updates the internal data structure with statistic data // retrieved from caches inside the in-memory data grid... Set<String> cacheNames = cacheList.keySet(); for (String cacheName : cacheNames) { Set resultSet = jmxServer.queryNames( new ObjectName("Coherence:type=Cache,name=" + cacheName + ",*"), null); for (Object resultSetRef : resultSet) { ObjectName objectName = (ObjectName) resultSetRef; if (objectName.getKeyProperty("tier").equals("back")) { int unit = (Integer) jmxServer.getAttribute(objectName, "Units"); int size = (Integer) jmxServer.getAttribute(objectName, "Size"); Statistics statistics = (Statistics) cacheList.get(cacheName); statistics.incrementUnit(unit); statistics.incrementSize(size); cacheList.put(cacheName, statistics); } } } // Finally... print the objects from the internal data // structure that represents the statistics from caches... cacheNames = cacheList.keySet(); for (String cacheName : cacheNames) { Statistics estatisticas = (Statistics) cacheList.get(cacheName); System.out.println(estatisticas); } } public MBeanServer getJMXServer() { MBeanServer jmxServer = null; for (Object jmxServerRef : MBeanServerFactory.findMBeanServer(null)) { jmxServer = (MBeanServer) jmxServerRef; if (jmxServer.getDefaultDomain().equals(DEFAULT_DOMAIN) || DEFAULT_DOMAIN.length() == 0) { break; } jmxServer = null; } if (jmxServer == null) { jmxServer = MBeanServerFactory.createMBeanServer(DEFAULT_DOMAIN); } return jmxServer; } private class Statistics { private long unit; private long size; private String cacheName; public Statistics(String cacheName) { this.cacheName = cacheName; } public void incrementUnit(long unit) { this.unit += unit; } public void incrementSize(long size) { this.size += size; } public long getUnit() { return unit; } public long getSize() { return size; } public double getUnitInMB() { return unit / (1024.0 * 1024.0); } public double getAverageSize() { return size == 0 ? 0 : unit / size; } public String toString() { StringBuffer sb = new StringBuffer(); sb.append("\nCache Statistics of '").append(cacheName).append("':\n"); sb.append(" - Total Entries of Cache -----> " + getSize()).append("\n"); sb.append(" - Used Memory (Bytes) --------> " + getUnit()).append("\n"); sb.append(" - Used Memory (MB) -----------> " + FORMAT.format(getUnitInMB())).append("\n"); sb.append(" - Object Average Size --------> " + FORMAT.format(getAverageSize())).append("\n"); return sb.toString(); } } public static void main(String[] args) throws Exception { new CalculateTheSizeOfPeopleCache().run(); } public static final DecimalFormat FORMAT = new DecimalFormat("###.###"); public static final String DEFAULT_DOMAIN = ""; public static final String DOMAIN_NAME = "Coherence"; } I've commented the overall example so, I don't think that you should get into trouble to understand it. Basically we are dealing with JMX. The first thing to do is enable JMX support for the Coherence client (ie, an JVM that will only retrieve values from the data grid and will not integrate the cluster) application. This can be done very easily using the runtime "tangosol.coherence.management" system property. Consult the Coherence documentation for JMX to understand the possible values that could be applied. The program creates an in memory data structure that holds a custom class created called "Statistics". This class represents the information that we are interested to see, which in this case are the size in bytes and in MB of the caches. An instance of this class is created for each cache that are currently managed by the data grid. Using JMX specific methods, we retrieve the information that are relevant for calculate the total size of the caches. To test this example, you should execute first the CreatePeopleCacheAndPopulateWithData.java program and after the CreatePeopleCacheAndPopulateWithData.java program. The results in the console should be something like this: 2012-06-23 13:29:31.188/4.970 Oracle Coherence 3.6.0.4 <Info> (thread=Main Thread, member=n/a): Loaded operational configuration from "jar:file:/E:/Oracle/Middleware/oepe_11gR1PS4/workspace/calcular-tamanho-cache-coherence/lib/coherence.jar!/tangosol-coherence.xml" 2012-06-23 13:29:31.219/5.001 Oracle Coherence 3.6.0.4 <Info> (thread=Main Thread, member=n/a): Loaded operational overrides from "jar:file:/E:/Oracle/Middleware/oepe_11gR1PS4/workspace/calcular-tamanho-cache-coherence/lib/coherence.jar!/tangosol-coherence-override-dev.xml" 2012-06-23 13:29:31.219/5.001 Oracle Coherence 3.6.0.4 <D5> (thread=Main Thread, member=n/a): Optional configuration override "/tangosol-coherence-override.xml" is not specified 2012-06-23 13:29:31.266/5.048 Oracle Coherence 3.6.0.4 <D5> (thread=Main Thread, member=n/a): Optional configuration override "/custom-mbeans.xml" is not specified Oracle Coherence Version 3.6.0.4 Build 19111 Grid Edition: Development mode Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. 2012-06-23 13:29:33.156/6.938 Oracle Coherence GE 3.6.0.4 <Info> (thread=Main Thread, member=n/a): Loaded Reporter configuration from "jar:file:/E:/Oracle/Middleware/oepe_11gR1PS4/workspace/calcular-tamanho-cache-coherence/lib/coherence.jar!/reports/report-group.xml" 2012-06-23 13:29:33.500/7.282 Oracle Coherence GE 3.6.0.4 <Info> (thread=Main Thread, member=n/a): Loaded cache configuration from "jar:file:/E:/Oracle/Middleware/oepe_11gR1PS4/workspace/calcular-tamanho-cache-coherence/lib/coherence.jar!/coherence-cache-config.xml" 2012-06-23 13:29:35.391/9.173 Oracle Coherence GE 3.6.0.4 <D4> (thread=Main Thread, member=n/a): TCMP bound to /192.168.177.133:8090 using SystemSocketProvider 2012-06-23 13:29:37.062/10.844 Oracle Coherence GE 3.6.0.4 <Info> (thread=Cluster, member=n/a): This Member(Id=2, Timestamp=2012-06-23 13:29:36.899, Address=192.168.177.133:8090, MachineId=55685, Location=process:244, Role=Oracle, Edition=Grid Edition, Mode=Development, CpuCount=2, SocketCount=2) joined cluster "cluster:0xC4DB" with senior Member(Id=1, Timestamp=2012-06-23 13:29:14.031, Address=192.168.177.133:8088, MachineId=55685, Location=process:1128, Role=CreatePeopleCacheAndPopulateWith, Edition=Grid Edition, Mode=Development, CpuCount=2, SocketCount=2) 2012-06-23 13:29:37.172/10.954 Oracle Coherence GE 3.6.0.4 <D5> (thread=Cluster, member=n/a): Member 1 joined Service Cluster with senior member 1 2012-06-23 13:29:37.188/10.970 Oracle Coherence GE 3.6.0.4 <D5> (thread=Cluster, member=n/a): Member 1 joined Service Management with senior member 1 2012-06-23 13:29:37.188/10.970 Oracle Coherence GE 3.6.0.4 <D5> (thread=Cluster, member=n/a): Member 1 joined Service DistributedCache with senior member 1 2012-06-23 13:29:37.188/10.970 Oracle Coherence GE 3.6.0.4 <Info> (thread=Main Thread, member=n/a): Started cluster Name=cluster:0xC4DB Group{Address=224.3.6.0, Port=36000, TTL=4} MasterMemberSet ( ThisMember=Member(Id=2, Timestamp=2012-06-23 13:29:36.899, Address=192.168.177.133:8090, MachineId=55685, Location=process:244, Role=Oracle) OldestMember=Member(Id=1, Timestamp=2012-06-23 13:29:14.031, Address=192.168.177.133:8088, MachineId=55685, Location=process:1128, Role=CreatePeopleCacheAndPopulateWith) ActualMemberSet=MemberSet(Size=2, BitSetCount=2 Member(Id=1, Timestamp=2012-06-23 13:29:14.031, Address=192.168.177.133:8088, MachineId=55685, Location=process:1128, Role=CreatePeopleCacheAndPopulateWith) Member(Id=2, Timestamp=2012-06-23 13:29:36.899, Address=192.168.177.133:8090, MachineId=55685, Location=process:244, Role=Oracle) ) RecycleMillis=1200000 RecycleSet=MemberSet(Size=0, BitSetCount=0 ) ) TcpRing{Connections=[1]} IpMonitor{AddressListSize=0} 2012-06-23 13:29:37.891/11.673 Oracle Coherence GE 3.6.0.4 <D5> (thread=Invocation:Management, member=2): Service Management joined the cluster with senior service member 1 2012-06-23 13:29:39.203/12.985 Oracle Coherence GE 3.6.0.4 <D5> (thread=DistributedCache, member=2): Service DistributedCache joined the cluster with senior service member 1 2012-06-23 13:29:39.297/13.079 Oracle Coherence GE 3.6.0.4 <D4> (thread=DistributedCache, member=2): Asking member 1 for 128 primary partitions Cache Statistics of 'People': - Total Entries of Cache -----> 3 - Used Memory (Bytes) --------> 883920 - Used Memory (MB) -----------> 0.843 - Object Average Size --------> 294640 I hope that this post could save you some time when calculate the total size of Coherence cache became a requirement for your high scalable system using data grids. See you!

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  • Per-vertex position/normal and per-index texture coordinate

    - by Boreal
    In my game, I have a mesh with a vertex buffer and index buffer up and running. The vertex buffer stores a Vector3 for the position and a Vector2 for the UV coordinate for each vertex. The index buffer is a list of ushorts. It works well, but I want to be able to use 3 discrete texture coordinates per triangle. I assume I have to create another vertex buffer, but how do I even use it? Here is my vertex/index buffer creation code: // vertices is a Vertex[] // indices is a ushort[] // VertexDefs stores the vertex size (sizeof(float) * 5) // vertex data numVertices = vertices.Length; DataStream data = new DataStream(VertexDefs.size * numVertices, true, true); data.WriteRange<Vertex>(vertices); data.Position = 0; // vertex buffer parameters BufferDescription vbDesc = new BufferDescription() { BindFlags = BindFlags.VertexBuffer, CpuAccessFlags = CpuAccessFlags.None, OptionFlags = ResourceOptionFlags.None, SizeInBytes = VertexDefs.size * numVertices, StructureByteStride = VertexDefs.size, Usage = ResourceUsage.Default }; // create vertex buffer vertexBuffer = new Buffer(Graphics.device, data, vbDesc); vertexBufferBinding = new VertexBufferBinding(vertexBuffer, VertexDefs.size, 0); data.Dispose(); // index data numIndices = indices.Length; data = new DataStream(sizeof(ushort) * numIndices, true, true); data.WriteRange<ushort>(indices); data.Position = 0; // index buffer parameters BufferDescription ibDesc = new BufferDescription() { BindFlags = BindFlags.IndexBuffer, CpuAccessFlags = CpuAccessFlags.None, OptionFlags = ResourceOptionFlags.None, SizeInBytes = sizeof(ushort) * numIndices, StructureByteStride = sizeof(ushort), Usage = ResourceUsage.Default }; // create index buffer indexBuffer = new Buffer(Graphics.device, data, ibDesc); data.Dispose(); Engine.Log(MessageType.Success, string.Format("Mesh created with {0} vertices and {1} indices", numVertices, numIndices)); And my drawing code: // ShaderEffect, ShaderTechnique, and ShaderPass all store effect data // e is of type ShaderEffect // get the technique ShaderTechnique t; if(!e.techniques.TryGetValue(techniqueName, out t)) return; // effect variables e.SetMatrix("worldView", worldView); e.SetMatrix("projection", projection); e.SetResource("diffuseMap", texture); e.SetSampler("textureSampler", sampler); // set per-mesh/technique settings Graphics.context.InputAssembler.SetVertexBuffers(0, vertexBufferBinding); Graphics.context.InputAssembler.SetIndexBuffer(indexBuffer, SlimDX.DXGI.Format.R16_UInt, 0); Graphics.context.PixelShader.SetSampler(sampler, 0); // render for each pass foreach(ShaderPass p in t.passes) { Graphics.context.InputAssembler.InputLayout = p.layout; p.pass.Apply(Graphics.context); Graphics.context.DrawIndexed(numIndices, 0, 0); } How can I do this?

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  • Stumbling Through: Visual Studio 2010 (Part I)

    Ive spent the better part of the last two years doing nothing but K2 workflow development, which until very recently could only be done in Visual Studio 2005 so I am a bit behind the times. I seem to have skipped over using Visual Studio 2008 entirely, and I am now ready to stumble through all that Ive missed. Not that I will abandon my K2 ramblings, but I need to get back to some of the other technologies I am passionate about but havent had the option of working with them on a day-to-day basis as I have with K2 blackpearl. Specifically, I am going to be focusing my efforts on what is new in the Entity Framework and WPF in Visual Studio 2010, though you have to keep in mind that since I have skipped VS 2008, I may be giving VS 2010 credit for things that really have been around for a while (hey, if I havent seen it, it is new to me!). I have the following simple goals in mind for this exercise: Entity Framework Model an inherited class Entity Framework Model a lookup entity WPF Bind a list of entities WPF - on selection of an entity in the bound list, display values of the selected entity WPF For the lookup field, provide a dropdown of potential values to lookup All of these goals must be accomplished using as little code as possible, relying on the features we get out of the box in Visual Studio 2010. This isnt going to be rocket science here, Im not even looking to get or save this data from/to a data source, but I gotta start somewhere and hopefully it will grow into something more interesting. For this exercise, I am going to try to model some fictional data about football players and personnel (maybe turning this into some sort of NFL simulation game if I lose my job and can play with this all day), so Ill start with a Person class that has a name property, and extend that with a Player class to include a Position lookup property. The idea is that a Person can be a Player, Coach or whatever other personnel type may be associated with a football team but well only flesh out the Player aspect of a person for this. So to get started, I fired up Visual Studio 2010 and created a new WPF Application: To this project, I added a new ADO.NET Entity Data Model named PlayerModel (for now, not sure what will be an appropriate name so this may be revisited): I chose for it to be an empty model, as I dont have a database designed for this yet: Using the toolbox, I dragged out an entity for each of the items we identified earlier: Person, Player and Position, and gave them some simple properties (note that I kept the default Id property for each of them): Now to figure out how to link these things together the way I want to first, lets try to tell it that Player extends Person. I see that Inheritance is one of the items in the toolbox, but I cant seem to drag it out anywhere onto the canvas. However, when I right-click an element, I get the option to Add Inheritance to it, which gives us exactly what we want: Ok, now that we have that, how do we tell it that each player has a position? Well, despite association being in the toolbox, I have learned that you cant just drag and drop those elements so I right click Player and select Add -> Association to get the following dialog: I see the option here to Add foreign key properties to my entities Ive read somewhere this this is a new and highly-sought after feature so Ill see what it does. Selecting it includes a PositionId on the Player element for me, which seems pretty database-centric and I would like to see if I can live without it for now given that we also got the Position property out of this association. Ill bring it back into the fold if it ends up being useful later. Here is what we end up with now: Trying to compile this resulted in an error stating that the Player entity cannot have an Id, because the Person element it extends already has a property named Id. Makes sense, so I remove it and compile again. Success, but with a warning but success is a good thing so Ill pretend I didnt see that warning for now. It probably has to do with the fact that my Player entity is now pretty useless as it doesnt have any non-navigation properties. So things seem to match what we are going for, great now what the heck do we do with this? Lets switch gears and see what we get for free dealing with this model from the UI. Lets open up the MainWindow.xaml and see if we can connect to our entities as a data source. Hey, whats this? Have you read my mind, Visual Studio? Our entities are already listed in the Data Sources panel: I do notice, however, that our Player entity is missing. Is this due to that compilation warning? Ill add a bogus property to our player entity just to see if that is the case no, still no love. The warning reads: Error 2062: No mapping specified for instances of the EntitySet and AssociationSet in the EntityContainer PlayerModelContainer. Well if everything worked without any issues, then I wouldnt be stumbling through at all, so lets get to the bottom of this. My good friend google indicates that the warning is due to the model not being tied up to a database. Hmmm, so why dont Players show up in my data sources? A little bit of drill-down shows that they are, in fact, exposed under Positions: Well now that isnt quite what I want. While you could get to players through a position, it shouldnt be that way exclusively. Oh well, I can ignore that for now lets drag Players out onto the canvas after selecting List from the dropdown: Hey, what the heck? I wanted a list not a listview. Get rid of that list view that was just dropped, drop in a listbox and then drop the Players entity into it. That will bind it for us. Of course, there isnt any data to show, which brings us to the really hacky part of all this and that is to stuff some test data into our view source without actually getting it from any data source. To do this through code, we need to grab a reference to the positionsPlayersViewSource resource that was created for us when we dragged out our Players entity. We then set the source of that reference equal to a populated list of Players.  Well add a couple of players that way as well as a few positions via the positionsViewSource resource, and Ill ensure that each player has a position specified.  Ultimately, the code looks like this: System.Windows.Data.CollectionViewSource positionViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("positionsViewSource")));             List<Position> positions = new List<Position>();             Position newPosition = new Position();             newPosition.Id = 0;             newPosition.Name = "WR";             positions.Add(newPosition);             newPosition = new Position();             newPosition.Id = 1;             newPosition.Name = "RB";             positions.Add(newPosition);             newPosition = new Position();             newPosition.Id = 2;             newPosition.Name = "QB";             positions.Add(newPosition);             positionViewSource.Source = positions;             System.Windows.Data.CollectionViewSource playerViewSource = ((System.Windows.Data.CollectionViewSource)(this.FindResource("positionsPlayersViewSource")));             List<Player> players = new List<Player>();             Player newPlayer = new Player();             newPlayer.Id = 0;             newPlayer.Name = "Test Dude";             newPlayer.Position = positions[0];             players.Add(newPlayer);             newPlayer = new Player();             newPlayer.Id = 1;             newPlayer.Name = "Test Dude II";             newPlayer.Position = positions[1];             players.Add(newPlayer);             newPlayer = new Player();             newPlayer.Id = 2;             newPlayer.Name = "Test Dude III";             newPlayer.Position = positions[2];             players.Add(newPlayer);             playerViewSource.Source = players; Now that our views are being loaded with data, we can go about tying things together visually. Drop a text box (to show the selected players name) and a combo box (to show the selected players position). Drag the Positions entity from the data sources panel to the combo box to wire it up to the positions view source. Click the text box that was dragged, and find its Text property in the properties pane. There is a little glyph next to it that displays Advanced Properties when hovered over click this and then select Apply Data Binding. In the dialog that appears, we can select the current players name as the value to bind to: Similarly, we can wire up the combo boxs SelectedItem value to the current players position: When the application is executed and we navigate through the various players, we automatically get their name and position bound to the appropriate fields: All of this was accomplished with no code save for loading the test data, and I might add, it was pretty intuitive to do so via the drag and drop of entities straight from the data sources panel. So maybe all of this was old hat to you, but I was very impressed with this experience and I look forward to stumbling through the caveats of doing more complex data modeling and binding in this fashion. Next up, I suppose, will be figuring out how to get the entities to get real data from a data source instead of stuffing it with test data as well as trying to figure out why Players ended up being under Positions in the data sources panel.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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  • How to keep a data structure synchronized over a network?

    - by David Gouveia
    Context In the game I'm working on (a sort of a point and click graphic adventure), pretty much everything that happens in the game world is controlled by an action manager that is structured a bit like: So for instance if the result of examining an object should make the character say hello, walk a bit and then sit down, I simply spawn the following code: var actionGroup = actionManager.CreateGroup(); actionGroup.Add(new TalkAction("Guybrush", "Hello there!"); actionGroup.Add(new WalkAction("Guybrush", new Vector2(300, 300)); actionGroup.Add(new SetAnimationAction("Guybrush", "Sit")); This creates a new action group (an entire line in the image above) and adds it to the manager. All of the groups are executed in parallel, but actions within each group are chained together so that the second one only starts after the first one finishes. When the last action in a group finishes, the group is destroyed. Problem Now I need to replicate this information across a network, so that in a multiplayer session, all players see the same thing. Serializing the individual actions is not the problem. But I'm an absolute beginner when it comes to networking and I have a few questions. I think for the sake of simplicity in this discussion we can abstract the action manager component to being simply: var actionManager = new List<List<string>>(); How should I proceed to keep the contents of the above data structure syncronized between all players? Besides the core question, I'm also having a few other concerns related to it (i.e. all possible implications of the same problem above): If I use a server/client architecture (with one of the players acting as both a server and a client), and one of the clients has spawned a group of actions, should he add them directly to the manager, or only send a request to the server, which in turn will order every client to add that group? What about packet losses and the like? The game is deterministic, but I'm thinking that any discrepancy in the sequence of actions executed in a client could lead to inconsistent states of the world. How do I safeguard against that sort of problem? What if I add too many actions at once, won't that cause problems for the connection? Any way to alleviate that?

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  • How can you tell whether to use Composite Pattern or a Tree Structure, or a third implementation?

    - by Aske B.
    I have two client types, an "Observer"-type and a "Subject"-type. They're both associated with a hierarchy of groups. The Observer will receive (calendar) data from the groups it is associated with throughout the different hierarchies. This data is calculated by combining data from 'parent' groups of the group trying to collect data (each group can have only one parent). The Subject will be able to create the data (that the Observers will receive) in the groups they're associated with. When data is created in a group, all 'children' of the group will have the data as well, and they will be able to make their own version of a specific area of the data, but still linked to the original data created (in my specific implementation, the original data will contain time-period(s) and headline, while the subgroups specify the rest of the data for the receivers directly linked to their respective groups). However, when the Subject creates data, it has to check if all affected Observers have any data that conflicts with this, which means a huge recursive function, as far as I can understand. So I think this can be summed up to the fact that I need to be able to have a hierarchy that you can go up and down in, and some places be able to treat them as a whole (recursion, basically). Also, I'm not just aiming at a solution that works. I'm hoping to find a solution that is relatively easy to understand (architecture-wise at least) and also flexible enough to be able to easily receive additional functionality in the future. Is there a design pattern, or a good practice to go by, to solve this problem or similar hierarchy problems? EDIT: Here's the design I have: The "Phoenix"-class is named that way because I didn't think of an appropriate name yet. But besides this I need to be able to hide specific activities for specific observers, even though they are attached to them through the groups. A little Off-topic: Personally, I feel that I should be able to chop this problem down to smaller problems, but it escapes me how. I think it's because it involves multiple recursive functionalities that aren't associated with each other and different client types that needs to get information in different ways. I can't really wrap my head around it. If anyone can guide me in a direction of how to become better at encapsulating hierarchy problems, I'd be very glad to receive that as well.

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  • Entities used to serialize data have changed. How can the serialized data be upgraded for the new entities?

    - by i8abug
    Hi, I have a bunch of simple entity instances that I have serialized to a file. In the future, I know that the structure of these entities (ie, maybe I will rename Name to Header or something). The thing is, I don't want to lose the data that I have saved in all these old files. What is the proper way to either load the data from the old entities into new entities upgrade the old files so that they can be used with new entities Note: I think I am stuck with binary serialization, not xml serialization. Thanks in advance! Edit: So I have an answer for the case I have described. I can use a dataContractSerializer and do something like [DataMember("bar")] private string foo; and change the name in the code and keep the same name that was used for serialization. But what about the following additional cases: The original entity has new members which can be serialized Some serialized members that were in the original entity are removed Some members have actually changed in function (suppose that the original class had a FirstName and LastName member and it has been refactored to have only a FullName member which combines the two) To handle these, I need some sort of interpreter/translator deserialization class but I have no idea what I should use

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  • byte and short data types in Java can accept the value outside the range by explicit cast. The higher data types however can not. Why?

    - by Lion
    Let's consider the following expressions in Java. byte a = 32; byte b = (byte) 250; int i = a + b; This is valid in Java even though the expression byte b = (byte) 250; is forced to assign the value 250 to b which is outside the range of the type byte. Therefore, b is assigned -6 and consequently i is assigned the value 26 through the statement int i = a + b;. The same thing is possible with short as follows. short s1=(short) 567889999; Although the specified value is outside the range of short, this statement is legal. The same thing is however wrong with higher data types such int, double, folat etc and hence, the following case is invalid and causes a compile-time error. int z=2147483648; This is illegal, since the range of int in Java is from -2,147,483,648 to 2147483647 which the above statement exceeds and issues a compile-time error. Why is such not wrong with byte and short data types in Java?

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  • wondering how much data bandwidth can a 3G gsm cell tower can support?

    - by Karim
    i was always wondering how many simaltinues users can a 3G tower supports with its data rates? i mean they advertize 28.8Mb/Sec for the 3G Data but in reallity if a lot of people use it say 10 , it wont give 288Mb/Sec bandwidth. i didnt find anywhere where such information is published so i thought to ask here. dont know why the cell operators keep it such a secret :)

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