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• Oracle VM RAC template - what it took

  - by wcoekaer

  In my previous posting I introduced the latest Oracle Real Application Cluster / Oracle VM template. I mentioned how easy it is to deploy a complete Oracle RAC cluster with Oracle VM. In fact, you don't need any prior knowledge at all to get a complete production-ready setup going. Here is an example... I built a 4 node RAC cluster, completely configured in just over 40 minutes - starting from import template into Oracle VM, create VMs to fully up and running Oracle RAC. And what was needed? 1 textfile with some hostnames and ip addresses and deploycluster.py. The setup is a 4 node cluster where each VM has 8GB of RAM and 4 vCPUs. The shared ASM storage in this case is 100GB, 5 x 20GB volumes. The VM names are racovm.0-racovm.3. The deploycluster script starts the VMs, verifies the configuration and sends the database cluster configuration info through Oracle VM Manager to the 4 node VMs. Once the VMs are up and running, the first VM starts the actual Oracle RAC setup inside and talks to the 3 other VMs. I did not log into any VM until after everything was completed. In fact, I connected to the database remotely before logging in at all. # ./deploycluster.py -u admin -H localhost --vms racovm.0,racovm.1,racovm.2,racovm.3 --netconfig ./netconfig.ini Oracle RAC OneCommand (v1.1.0) for Oracle VM - deploy cluster - (c) 2011-2012 Oracle Corporation (com: 26700:v1.1.0, lib: 126247:v1.1.0, var: 1100:v1.1.0) - v2.4.3 - wopr8.wimmekes.net (x86_64) Invoked as root at Sat Jun 2 17:31:29 2012 (size: 37500, mtime: Wed May 16 00:13:19 2012) Using: ./deploycluster.py -u admin -H localhost --vms racovm.0,racovm.1,racovm.2,racovm.3 --netconfig ./netconfig.ini INFO: Login password to Oracle VM Manager not supplied on command line or environment (DEPLOYCLUSTER_MGR_PASSWORD), prompting... Password: INFO: Attempting to connect to Oracle VM Manager... INFO: Oracle VM Client (3.1.1.305) protocol (1.8) CONNECTED (tcp) to Oracle VM Manager (3.1.1.336) protocol (1.8) IP (192.168.1.40) UUID (0004fb0000010000cbce8a3181569a3e) INFO: Inspecting /root/rac/deploycluster/netconfig.ini for number of nodes defined... INFO: Detected 4 nodes in: /root/rac/deploycluster/netconfig.ini INFO: Located a total of (4) VMs; 4 VMs with a simple name of: ['racovm.0', 'racovm.1', 'racovm.2', 'racovm.3'] INFO: Verifying all (4) VMs are in Running state INFO: VM with a simple name of "racovm.0" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.1" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.2" is in a Stopped state, attempting to start it...OK. INFO: VM with a simple name of "racovm.3" is in a Stopped state, attempting to start it...OK. INFO: Detected that all (4) VMs specified on command have (5) common shared disks between them (ASM_MIN_DISKS=5) INFO: The (4) VMs passed basic sanity checks and in Running state, sending cluster details as follows: netconfig.ini (Network setup): /root/rac/deploycluster/netconfig.ini buildcluster: yes INFO: Starting to send cluster details to all (4) VM(s)....... INFO: Sending to VM with a simple name of "racovm.0".... INFO: Sending to VM with a simple name of "racovm.1"..... INFO: Sending to VM with a simple name of "racovm.2"..... INFO: Sending to VM with a simple name of "racovm.3"...... INFO: Cluster details sent to (4) VMs... Check log (default location /u01/racovm/buildcluster.log) on build VM (racovm.0)... INFO: deploycluster.py completed successfully at 17:32:02 in 33.2 seconds (00m:33s) Logfile at: /root/rac/deploycluster/deploycluster2.log my netconfig.ini # Node specific information NODE1=db11rac1 NODE1VIP=db11rac1-vip NODE1PRIV=db11rac1-priv NODE1IP=192.168.1.56 NODE1VIPIP=192.168.1.65 NODE1PRIVIP=192.168.2.2 NODE2=db11rac2 NODE2VIP=db11rac2-vip NODE2PRIV=db11rac2-priv NODE2IP=192.168.1.58 NODE2VIPIP=192.168.1.66 NODE2PRIVIP=192.168.2.3 NODE3=db11rac3 NODE3VIP=db11rac3-vip NODE3PRIV=db11rac3-priv NODE3IP=192.168.1.173 NODE3VIPIP=192.168.1.174 NODE3PRIVIP=192.168.2.4 NODE4=db11rac4 NODE4VIP=db11rac4-vip NODE4PRIV=db11rac4-priv NODE4IP=192.168.1.175 NODE4VIPIP=192.168.1.176 NODE4PRIVIP=192.168.2.5 # Common data PUBADAP=eth0 PUBMASK=255.255.255.0 PUBGW=192.168.1.1 PRIVADAP=eth1 PRIVMASK=255.255.255.0 RACCLUSTERNAME=raccluster DOMAINNAME=wimmekes.net DNSIP= # Device used to transfer network information to second node # in interview mode NETCONFIG_DEV=/dev/xvdc # 11gR2 specific data SCANNAME=db11vip SCANIP=192.168.1.57 last few lines of the in-VM log file : 2012-06-02 14:01:40:[clusterstate:Time :db11rac1] Completed successfully in 2 seconds (0h:00m:02s) 2012-06-02 14:01:40:[buildcluster:Done :db11rac1] Build 11gR2 RAC Cluster 2012-06-02 14:01:40:[buildcluster:Time :db11rac1] Completed successfully in 1779 seconds (0h:29m:39s) From start_vm to completely configured : 29m:39s. The other 10m was the import template and create 4 VMs from template along with the shared storage configuration. This consists of a complete Oracle 11gR2 RAC database with ASM, CRS and the RDBMS up and running on all 4 nodes. Simply connect and use. Production ready. Oracle on Oracle.

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• ODI 12c - Aggregating Data

  - by David Allan

  This posting will look at the aggregation component that was introduced in ODI 12c. For many ETL tool users this shouldn't be a big surprise, its a little different than ODI 11g but for good reason. You can use this component for composing data with relational like operations such as sum, average and so forth. Also, Oracle SQL supports special functions called Analytic SQL functions, you can use a specially configured aggregation component or the expression component for these now in ODI 12c. In database systems an aggregate transformation is a transformation where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning - that's exactly the purpose of the aggregate component. In the image below you can see the aggregate component in action within a mapping, for how this and a few other examples are built look at the ODI 12c Aggregation Viewlet here - the viewlet illustrates a simple aggregation being built and then some Oracle analytic SQL such as AVG(EMP.SAL) OVER (PARTITION BY EMP.DEPTNO) built using both the aggregate component and the expression component. In 11g you used to just write the aggregate expression directly on the target, this made life easy for some cases, but it wan't a very obvious gesture plus had other drawbacks with ordering of transformations (agg before join/lookup. after set and so forth) and supporting analytic SQL for example - there are a lot of postings from creative folks working around this in 11g - anything from customizing KMs, to bypassing aggregation analysis in the ODI code generator. The aggregate component has a few interesting aspects. 1. Firstly and foremost it defines the attributes projected from it - ODI automatically will perform the grouping all you do is define the aggregation expressions for those columns aggregated. In 12c you can control this automatic grouping behavior so that you get the code you desire, so you can indicate that an attribute should not be included in the group by, that's what I did in the analytic SQL example using the aggregate component. 2. The component has a few other properties of interest; it has a HAVING clause and a manual group by clause. The HAVING clause includes a predicate used to filter rows resulting from the GROUP BY clause. Because it acts on the results of the GROUP BY clause, aggregation functions can be used in the HAVING clause predicate, in 11g the filter was overloaded and used for both having clause and filter clause, this is no longer the case. If a filter is after an aggregate, it is after the aggregate (not sometimes after, sometimes having).  3. The manual group by clause let's you use special database grouping grammar if you need to. For example Oracle has a wealth of highly specialized grouping capabilities for data warehousing such as the CUBE function. If you want to use specialized functions like that you can manually define the code here. The example below shows the use of a manual group from an example in the Oracle database data warehousing guide where the SUM aggregate function is used along with the CUBE function in the group by clause. The SQL I am trying to generate looks like the following from the data warehousing guide; SELECT channel_desc, calendar_month_desc, countries.country_iso_code,       TO_CHAR(SUM(amount_sold), '9,999,999,999') SALES$ FROM sales, customers, times, channels, countries WHERE sales.time_id=times.time_id AND sales.cust_id=customers.cust_id AND   sales.channel_id= channels.channel_id  AND customers.country_id = countries.country_id  AND channels.channel_desc IN   ('Direct Sales', 'Internet') AND times.calendar_month_desc IN   ('2000-09', '2000-10') AND countries.country_iso_code IN ('GB', 'US') GROUP BY CUBE(channel_desc, calendar_month_desc, countries.country_iso_code); I can capture the source datastores, the filters and joins using ODI's dataset (or as a traditional flow) which enables us to incrementally design the mapping and the aggregate component for the sum and group by as follows; In the above mapping you can see the joins and filters declared in ODI's dataset, allowing you to capture the relationships of the datastores required in an entity-relationship style just like ODI 11g. The mix of ODI's declarative design and the common flow design provides for a familiar design experience. The example below illustrates flow design (basic arbitrary ordering) - a table load where only the employees who have maximum commission are loaded into a target. The maximum commission is retrieved from the bonus datastore and there is a look using employees as the driving table and only those with maximum commission projected. Hopefully this has given you a taster for some of the new capabilities provided by the aggregate component in ODI 12c. In summary, the actions should be much more consistent in behavior and more easily discoverable for users, the use of the components in a flow graph also supports arbitrary designs and the tool (rather than the interface designer) takes care of the realization using ODI's knowledge modules. Interested to know if a deep dive into each component is interesting for folks. Any thoughts? 

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• Scripting custom drawing in Delphi application with IF/THEN/ELSE statements?

  - by Jerry Dodge

  I'm building a Delphi application which displays a blueprint of a building, including doors, windows, wiring, lighting, outlets, switches, etc. I have implemented a very lightweight script of my own to call drawing commands to the canvas, which is loaded from a database. For example, one command is ELP 1110,1110,1290,1290,3,8388608 which draws an ellipse, parameters are 1110x1110 to 1290x1290 with pen width of 3 and the color 8388608 converted from an integer to a TColor. What I'm now doing is implementing objects with common drawing routines, and I'd like to use my scripting engine, but this calls for IF/THEN/ELSE statements and such. For example, when I'm drawing a light, if the light is turned on, I'd like to draw it yellow, but if it's off, I'd like to draw it gray. My current scripting engine has no recognition of such statements. It just accepts simple drawing commands which correspond with TCanvas methods. Here's the procedure I've developed (incomplete) for executing a drawing command on a canvas: function DrawCommand(const Cmd: String; var Canvas: TCanvas): Boolean; type TSingleArray = array of Single; var Br: TBrush; Pn: TPen; X: Integer; P: Integer; L: String; Inst: String; T: String; Nums: TSingleArray; begin Result:= False; Br:= Canvas.Brush; Pn:= Canvas.Pen; if Assigned(Canvas) then begin if Length(Cmd) > 5 then begin L:= UpperCase(Cmd); if Pos(' ', L)> 0 then begin Inst:= Copy(L, 1, Pos(' ', L) - 1); Delete(L, 1, Pos(' ', L)); L:= L + ','; SetLength(Nums, 0); X:= 0; while Pos(',', L) > 0 do begin P:= Pos(',', L); T:= Copy(L, 1, P - 1); Delete(L, 1, P); SetLength(Nums, X + 1); Nums[X]:= StrToFloatDef(T, 0); Inc(X); end; Br.Style:= bsClear; Pn.Style:= psSolid; Pn.Color:= clBlack; if Inst = 'LIN' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.MoveTo(Trunc(Nums[0]), Trunc(Nums[1])); Canvas.LineTo(Trunc(Nums[2]), Trunc(Nums[3])); Result:= True; end else if Inst = 'ELP' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.Ellipse(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3])); Result:= True; end else if Inst = 'ARC' then begin Pn.Width:= Trunc(Nums[8]); Canvas.Arc(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3]), Trunc(Nums[4]),Trunc(Nums[5]),Trunc(Nums[6]),Trunc(Nums[7])); Result:= True; end else if Inst = 'TXT' then begin Canvas.Font.Size:= Trunc(Nums[2]); Br.Style:= bsClear; Pn.Style:= psSolid; T:= Cmd; Delete(T, 1, Pos(' ', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Canvas.TextOut(Trunc(Nums[0]), Trunc(Nums[1]), T); Result:= True; end; end else begin //No space found, not a valid command end; end; end; end; What I'd like to know is what's a good lightweight third-party scripting engine I could use to accomplish this? I would hate to implement parsing of IF, THEN, ELSE, END, IFELSE, IFEND, and all those necessary commands. I need simply the ability to tell the scripting engine if certain properties meet certain conditions, it needs to draw the object a certain way. The light example above is only one scenario, but the same solution needs to also be applicable to other scenarios, such as a door being open or closed, locked or unlocked, and draw it a different way accordingly. This needs to be implemented in the object script drawing level. I can't hard-code any of these scripting/drawing rules, the drawing needs to be controlled based on the current state of the object, and I may also wish to draw a light a certain shade or darkness depending on how dimmed the light is.

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• Master Page: Dynamically Adding Rows in ASP Table on Button Click event

  - by Vincent Maverick Durano

  In my previous post here, I wrote an example that demonstrates how are we going to generate table rows dynamically using ASP Table on click of the Button control. Now based on some comments in my previous example and in the forums they wanted to implement it within Masterpage. Unfortunately the code in my previous example doesn't work in Masterpage for the following main reasons: The Table is dynamically added within the Form tag and so the TextBox control will not be generated correcty in the page. The data will not be retained on each and every postbacks because the SetPreviousData() method is looking for the Table element within the Page and not on the MasterPage. The Request.Form key value should be set correctly since all controls within the master page are prefixed with the naming containter ID to prevent duplicate ids on the final rendered HTML. For example the TextBox control with the ID of TextBoxRow will turn to ID to this ctl00$MainBody$TextBoxRow. In order for the previous example to work within Masterpage then we will have to correct those three main reasons above and this post will guide you how to correct it. Suppose we have this content page declaration below:   <asp:Content ID="Content1" ContentPlaceHolderID="MainHead" Runat="Server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainBody" Runat="Server"> <asp:PlaceHolder ID="PlaceHolder1" runat="server"> <asp:Button ID="BTNAdd" runat="server" Text="Add New Row" OnClick="BTNAdd_Click" /> </asp:PlaceHolder> </asp:Content> As you notice I've added a PlaceHolder control within the MainBody ContentPlaceHolder. This is because we are going to generate the Table in the PlaceHolder instead of generating it within the Form element. Now since issue #1 is already corrected then let's proceed to the code beind part. Here are the full code blocks below:     using System; using System.Web.UI; using System.Web.UI.WebControls; public partial class DynamicControlDemo : System.Web.UI.Page { private int numOfRows = 1; protected void Page_Load(object sender, EventArgs e) { //Generate the Rows on Initial Load if (!Page.IsPostBack) { GenerateTable(numOfRows); } } protected void BTNAdd_Click(object sender, EventArgs e) { if (ViewState["RowsCount"] != null) { numOfRows = Convert.ToInt32(ViewState["RowsCount"].ToString()); GenerateTable(numOfRows); } } private void SetPreviousData(int rowsCount, int colsCount) { Table table = (Table)this.Page.Master.FindControl("MainBody").FindControl("Table1"); // **** if (table != null) { for (int i = 0; i < rowsCount; i++) { for (int j = 0; j < colsCount; j++) { //Extracting the Dynamic Controls from the Table TextBox tb = (TextBox)table.Rows[i].Cells[j].FindControl("TextBoxRow_" + i + "Col_" + j); //Use Request object for getting the previous data of the dynamic textbox tb.Text = Request.Form["ctl00$MainBody$TextBoxRow_" + i + "Col_" + j];//***** } } } } private void GenerateTable(int rowsCount) { //Creat the Table and Add it to the Page Table table = new Table(); table.ID = "Table1"; PlaceHolder1.Controls.Add(table);//****** //The number of Columns to be generated const int colsCount = 3;//You can changed the value of 3 based on you requirements // Now iterate through the table and add your controls for (int i = 0; i < rowsCount; i++) { TableRow row = new TableRow(); for (int j = 0; j < colsCount; j++) { TableCell cell = new TableCell(); TextBox tb = new TextBox(); // Set a unique ID for each TextBox added tb.ID = "TextBoxRow_" + i + "Col_" + j; // Add the control to the TableCell cell.Controls.Add(tb); // Add the TableCell to the TableRow row.Cells.Add(cell); } // And finally, add the TableRow to the Table table.Rows.Add(row); } //Set Previous Data on PostBacks SetPreviousData(rowsCount, colsCount); //Sore the current Rows Count in ViewState rowsCount++; ViewState["RowsCount"] = rowsCount; } }   As you observed the code is pretty much similar to the previous example except for the highlighted lines above. That's it! I hope someone find this post usefu! Technorati Tags: Dynamic Controls,ASP.NET,C#,Master Page

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• How do I resolve this exercise on C++? [closed]

  - by user40630

  (Card Shuffling and Dealing) Create a program to shuffle and deal a deck of cards. The program should consist of class Card, class DeckOfCards and a driver program. Class Card should provide: a) Data members face and suit of type int. b) A constructor that receives two ints representing the face and suit and uses them to initialize the data members. c) Two static arrays of strings representing the faces and suits. d) A toString function that returns the Card as a string in the form “face of suit.” You can use the + operator to concatenate strings. Class DeckOfCards should contain: a) A vector of Cards named deck to store the Cards. b) An integer currentCard representing the next card to deal. c) A default constructor that initializes the Cards in the deck. The constructor should use vector function push_back to add each Card to the end of the vector after the Card is created and initialized. This should be done for each of the 52 Cards in the deck. d) A shuffle function that shuffles the Cards in the deck. The shuffle algorithm should iterate through the vector of Cards. For each Card, randomly select another Card in the deck and swap the two Cards. e) A dealCard function that returns the next Card object from the deck. f) A moreCards function that returns a bool value indicating whether there are more Cards to deal. The driver program should create a DeckOfCards object, shuffle the cards, then deal the 52 cards. This above is the exercise I'm trying to solve. I'd be very much appreciated if someone could solve it and explain it to me. The main idea of the program is quite simple. What I don't get is how to build the constructor for the class DeckOfCards and how to generate the 52 cards of the deck with different suits and faces. Untill now I've managed to do this: #include <iostream> #include <vector> using namespace std; /* * */ /* a) Data members face and suit of type int. b) A constructor that receives two ints representing the face and suit and uses them to initialize the data members. c) Two static arrays of strings representing the faces and suits. d) A toString function that returns the Card as a string in the form “face of suit.” You can use the + operator to concatenate strings. */ class Card { public: Card(int, int); string toString(); private: int suit, face; static string faceNames[13]; static string suitNames[4]; }; string Card::faceNames[13] = {"Ace","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten","Queen","Jack","King"}; string Card::suitNames[4] = {"Diamonds","Clubs","Hearts","Spades"}; string Card::toString() { return faceNames[face]+" of "+suitNames[suit]; } Card::Card(int f, int s) :face(f), suit(s) { } /* Class DeckOfCards should contain: a) A vector of Cards named deck to store the Cards. b) An integer currentCard representing the next card to deal. c) A default constructor that initializes the Cards in the deck. The constructor should use vector function push_back to add each Card to the end of the vector after the Card is created and initialized. This should be done for each of the 52 Cards in the deck. d) A shuffle function that shuffles the Cards in the deck. The shuffle algorithm should iterate through the vector of Cards. For each Card, randomly select another Card in the deck and swap the two Cards. e) A dealCard function that returns the next Card object from the deck. f) A moreCards function that returns a bool value indicating whether there are more Cards to deal. */ class DeckOfCards { public: DeckOfCards(); void shuffleCards(); Card dealCard(); bool moreCards(); private: vector<Card> deck(52); int currentCard; }; int main(int argc, char** argv) { return 0; } DeckOfCards::DeckOfCards() { //I'm stuck here I have no idea of what to take out of here. //I still don't fully get the idea of class inside class and that's turning out as a problem. I try to find a way to set the suits and faces members of the class Card but I can't figure out how. for(int i=0; i<deck.size(); i++) { deck[i]//....There is no function to set them. They must be set when initialized. But how?? } } For easier reading: http://pastebin.com/pJeXMH0f

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• Composing Silverlight Applications With MEF

  - by PeterTweed

  Anyone who has written an application with complexity enough to warrant multiple controls on multiple pages/forms should understand the benefit of composite application development.  That is defining your application architecture that can be separated into separate pieces each with it’s own distinct purpose that can then be “composed” together into the solution. Composition can be useful in any layer of the application, from the presentation layer, the business layer, common services or data access.  Historically people have had different options to achieve composing applications from distinct well known pieces – their own version of dependency injection, containers to aid with composition like Unity, the composite application guidance for WPF and Silverlight and before that the composite application block. Microsoft has been working on another mechanism to aid composition and extension of applications for some time now – the Managed Extensibility Framework or MEF for short.  With Silverlight 4 it is part of the Silverlight environment.  MEF allows a much simplified mechanism for composition and extensibility compared to other mechanisms – which has always been the primary issue for adoption of the earlier mechanisms/frameworks. This post will guide you through the simple use of MEF for the scenario of composition of an application – using exports, imports and composition.  Steps: 1.     Create a new Silverlight 4 application. 2.     Add references to the following assemblies: System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll 3.     Add a new user control called LeftControl. 4.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Beige" Margin="40" >         <Button Content="Left Content" Margin="30"></Button>     </Grid> 5.     Add the following statement to the top of the LeftControl.xaml.cs file using System.ComponentModel.Composition; 6.     Add the following attribute to the LeftControl class     [Export(typeof(LeftControl))]   This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application. 7.     Add a new user control called RightControl. 8.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Green" Margin="40"  >         <TextBlock Margin="40" Foreground="White" Text="Right Control" FontSize="16" VerticalAlignment="Center" HorizontalAlignment="Center" ></TextBlock>     </Grid> 9.     Add the following statement to the top of the RightControl.xaml.cs file using System.ComponentModel.Composition; 10.   Add the following attribute to the RightControl class     [Export(typeof(RightControl))] 11.   Add the following xaml to the LayoutRoot Grid in MainPage.xaml:         <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">             <Border Name="LeftContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>             <Border Name="RightContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>         </StackPanel>   The borders will hold the controls that will be imported and composed via MEF. 12.   Add the following statement to the top of the MainPage.xaml.cs file using System.ComponentModel.Composition; 13.   Add the following properties to the MainPage class:         [Import(typeof(LeftControl))]         public LeftControl LeftUserControl { get; set; }         [Import(typeof(RightControl))]         public RightControl RightUserControl { get; set; }   This defines properties accepting LeftControl and RightControl types.  The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs. 14.   Replace the MainPage constructore with the following code:         public MainPage()         {             InitializeComponent();             CompositionInitializer.SatisfyImports(this);             LeftContent.Child = LeftUserControl;             RightContent.Child = RightUserControl;         }   The CompositionInitializer.SatisfyImports(this) function call tells MEF to discover types related to the declared imports for this object (the MainPage object).  At that point, types matching those specified in the import defintions are discovered in the executing assembly location of the application and instantiated and assigned to the matching properties of the current object. 15.   Run the application and you will see the left control and right control types displayed in the MainPage:   Congratulations!  You have used MEF to dynamically compose user controls into a parent control in a composite application model. In the next post we will build on this topic to cover using MEF to compose Silverlight applications dynamically in download on demand scenarios – so .xap packages can be downloaded only when needed, avoiding large initial download for the main application xap. Take the Slalom Challenge at www.slalomchallenge.com!

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• SQL ADO.NET shortcut extensions (old school!)

  - by Jeff

  As much as I love me some ORM's (I've used LINQ to SQL quite a bit, and for the MSDN/TechNet Profile and Forums we're using NHibernate more and more), there are times when it's appropriate, and in some ways more simple, to just throw up so old school ADO.NET connections, commands, readers and such. It still feels like a pain though to new up all the stuff, make sure it's closed, blah blah blah. It's pretty much the least favorite task of writing data access code. To minimize the pain, I have a set of extension methods that I like to use that drastically reduce the code you have to write. Here they are... public static void Using(this SqlConnection connection, Action<SqlConnection> action) {     connection.Open();     action(connection);     connection.Close(); } public static SqlCommand Command(this SqlConnection connection, string sql){    var command = new SqlCommand(sql, connection);    return command;}public static SqlCommand AddParameter(this SqlCommand command, string parameterName, object value){    command.Parameters.AddWithValue(parameterName, value);    return command;}public static object ExecuteAndReturnIdentity(this SqlCommand command){    if (command.Connection == null)        throw new Exception("SqlCommand has no connection.");    command.ExecuteNonQuery();    command.Parameters.Clear();    command.CommandText = "SELECT @@IDENTITY";    var result = command.ExecuteScalar();    return result;}public static SqlDataReader ReadOne(this SqlDataReader reader, Action<SqlDataReader> action){    if (reader.Read())        action(reader);    reader.Close();    return reader;}public static SqlDataReader ReadAll(this SqlDataReader reader, Action<SqlDataReader> action){    while (reader.Read())        action(reader);    reader.Close();    return reader;} It has been awhile since I've really revisited these, so you will likely find opportunity for further optimization. The bottom line here is that you can chain together a bunch of these methods to make a much more concise database call, in terms of the code on your screen, anyway. Here are some examples: public Dictionary<string, string> Get(){    var dictionary = new Dictionary<string, string>();    _sqlHelper.GetConnection().Using(connection =>        connection.Command("SELECT Setting, [Value] FROM Settings")            .ExecuteReader()            .ReadAll(r => dictionary.Add(r.GetString(0), r.GetString(1))));    return dictionary;} or... public void ChangeName(User user, string newName){    _sqlHelper.GetConnection().Using(connection =>         connection.Command("UPDATE Users SET Name = @Name WHERE UserID = @UserID")            .AddParameter("@Name", newName)            .AddParameter("@UserID", user.UserID)            .ExecuteNonQuery());} The _sqlHelper.GetConnection() is just some other code that gets a connection object for you. You might have an even cleaner way to take that step out entirely. This looks more fluent, and the real magic sauce for me is the reader bits where you can put any kind of arbitrary method in there to iterate over the results.

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• C#/.NET Little Wonders: Getting Caller Information

  - by James Michael Hare

  Originally posted on: http://geekswithblogs.net/BlackRabbitCoder/archive/2013/07/25/c.net-little-wonders-getting-caller-information.aspx Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. There are times when it is desirable to know who called the method or property you are currently executing.  Some applications of this could include logging libraries, or possibly even something more advanced that may server up different objects depending on who called the method. In the past, we mostly relied on the System.Diagnostics namespace and its classes such as StackTrace and StackFrame to see who our caller was, but now in C# 5, we can also get much of this data at compile-time. Determining the caller using the stack One of the ways of doing this is to examine the call stack.  The classes that allow you to examine the call stack have been around for a long time and can give you a very deep view of the calling chain all the way back to the beginning for the thread that has called you. You can get caller information by either instantiating the StackTrace class (which will give you the complete stack trace, much like you see when an exception is generated), or by using StackFrame which gets a single frame of the stack trace.  Both involve examining the call stack, which is a non-trivial task, so care should be done not to do this in a performance-intensive situation. For our simple example let's say we are going to recreate the wheel and construct our own logging framework.  Perhaps we wish to create a simple method Log which will log the string-ified form of an object and some information about the caller.  We could easily do this as follows: 1: static void Log(object message) 2: { 3: // frame 1, true for source info 4: StackFrame frame = new StackFrame(1, true); 5: var method = frame.GetMethod(); 6: var fileName = frame.GetFileName(); 7: var lineNumber = frame.GetFileLineNumber(); 8: 9: // we'll just use a simple Console write for now 10: Console.WriteLine("{0}({1}):{2} - {3}", 11: fileName, lineNumber, method.Name, message); 12: } So, what we are doing here is grabbing the 2nd stack frame (the 1st is our current method) using a 2nd argument of true to specify we want source information (if available) and then taking the information from the frame.  This works fine, and if we tested it out by calling from a file such as this: 1: // File c:\projects\test\CallerInfo\CallerInfo.cs 2:  3: public class CallerInfo 4: { 5: Log("Hello Logger!"); 6: } We'd see this: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! This works well, and in fact CallStack and StackFrame are still the best ways to examine deeper into the call stack.  But if you only want to get information on the caller of your method, there is another option… Determining the caller at compile-time In C# 5 (.NET 4.5) they added some attributes that can be supplied to optional parameters on a method to receive caller information.  These attributes can only be applied to methods with optional parameters with explicit defaults.  Then, as the compiler determines who is calling your method with these attributes, it will fill in the values at compile-time. These are the currently supported attributes available in the  System.Runtime.CompilerServices namespace": CallerFilePathAttribute – The path and name of the file that is calling your method. CallerLineNumberAttribute – The line number in the file where your method is being called. CallerMemberName – The member that is calling your method. So let’s take a look at how our Log method would look using these attributes instead: 1: static int Log(object message, 2: [CallerMemberName] string memberName = "", 3: [CallerFilePath] string fileName = "", 4: [CallerLineNumber] int lineNumber = 0) 5: { 6: // we'll just use a simple Console write for now 7: Console.WriteLine("{0}({1}):{2} - {3}", 8: fileName, lineNumber, memberName, message); 9: } Again, calling this from our sample Main would give us the same result: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! However, though this seems the same, there are a few key differences. First of all, there are only 3 supported attributes (at this time) that give you the file path, line number, and calling member.  Thus, it does not give you as rich of detail as a StackFrame (which can give you the calling type as well and deeper frames, for example).  Also, these are supported through optional parameters, which means we could call our new Log method like this: 1: // They're defaults, why not fill 'em in 2: Log("My message.", "Some member", "Some file", -13); In addition, since these attributes require optional parameters, they cannot be used in properties, only in methods. These caveats aside, they do let you get similar information inside of methods at a much greater speed!  How much greater?  Well lets crank through 1,000,000 iterations of each.  instead of logging to console, I’ll return the formatted string length of each.  Doing this, we get: 1: Time for 1,000,000 iterations with StackTrace: 5096 ms 2: Time for 1,000,000 iterations with Attributes: 196 ms So you see, using the attributes is much, much faster!  Nearly 25x faster in fact.  Summary There are a few ways to get caller information for a method.  The StackFrame allows you to get a comprehensive set of information spanning the whole call stack, but at a heavier cost.  On the other hand, the attributes allow you to quickly get at caller information baked in at compile-time, but to do so you need to create optional parameters in your methods to support it. Technorati Tags: Little Wonders,CSharp,C#,.NET,StackFrame,CallStack,CallerFilePathAttribute,CallerLineNumberAttribute,CallerMemberName

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• PhP Login/Register system [migrated]

  - by Marian

  I found this good tutorial on creating a login/register system using PhP and MySQL. The forum is around 5 years old (edited last year) but it can still be usefull. Beginner Simple Register-Login system There seems to be an issue with both login and register pages. <?php function register_form(){ $date = date('D, M, Y'); echo "<form action='?act=register' method='post'>" ."Username: <input type='text' name='username' size='30'><br>" ."Password: <input type='password' name='password' size='30'><br>" ."Confirm your password: <input type='password' name='password_conf' size='30'><br>" ."Email: <input type='text' name='email' size='30'><br>" ."<input type='hidden' name='date' value='$date'>" ."<input type='submit' value='Register'>" ."</form>"; } function register(){ $connect = mysql_connect("host", "username", "password"); if(!$connect){ die(mysql_error()); } $select_db = mysql_select_db("database", $connect); if(!$select_db){ die(mysql_error()); } $username = $_REQUEST['username']; $password = $_REQUEST['password']; $pass_conf = $_REQUEST['password_conf']; $email = $_REQUEST['email']; $date = $_REQUEST['date']; if(empty($username)){ die("Please enter your username!<br>"); } if(empty($password)){ die("Please enter your password!<br>"); } if(empty($pass_conf)){ die("Please confirm your password!<br>"); } if(empty($email)){ die("Please enter your email!"); } $user_check = mysql_query("SELECT username FROM users WHERE username='$username'"); $do_user_check = mysql_num_rows($user_check); $email_check = mysql_query("SELECT email FROM users WHERE email='$email'"); $do_email_check = mysql_num_rows($email_check); if($do_user_check > 0){ die("Username is already in use!<br>"); } if($do_email_check > 0){ die("Email is already in use!"); } if($password != $pass_conf){ die("Passwords don't match!"); } $insert = mysql_query("INSERT INTO users (username, password, email) VALUES ('$username', '$password', '$email')"); if(!$insert){ die("There's little problem: ".mysql_error()); } echo $username.", you are now registered. Thank you!<br><a href=login.php>Login</a> | <a href=index.php>Index</a>"; } switch($act){ default; register_form(); break; case "register"; register(); break; } ?> Once pressed the register button the page does nothing, fields are erased and no data is added inside the database or error given. I tought that the problem might be the switch($act){ part so I removed it and changed the page using a require require('connect.php'); where connect.php is <?php mysql_connect("localhost","host","password"); mysql_select_db("database"); ?> Removed the function register_form(){ and echo part turning it into an HTML code: <form action='register' method='post'> Username: <input type='text' name='username' size='30'><br> Password: <input type='password' name='password' size='30'><br> Confirm your password: <input type='password' name='password_conf' size='30'><br> Email: <input type='text' name='email' size='30'><br> <input type='hidden' name='date' value='$date'> <input type='submit' name="register" value='Register'> </form> And instead of having a function register(){ I replaced it with a if($register){ So when the Register button is pressed it runs the php code, but this edit doesn't seem to work either. So what can the problem be? If needed I can re-add this code on my Domain The login page has the same issue, nothing happens when the button is pressed beside emptying the fields.

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• How is the gimbal locked problem solved using accumulative matrix transformations

  - by Luke San Antonio

  I am reading the online "Learning Modern 3D Graphics Programming" book by Jason L. McKesson As of now, I am up to the gimbal lock problem and how to solve it using quaternions. However right here, at the Quaternions page. Part of the problem is that we are trying to store an orientation as a series of 3 accumulated axial rotations. Orientations are orientations, not rotations. And orientations are certainly not a series of rotations. So we need to treat the orientation of the ship as an orientation, as a specific quantity. I guess this is the first spot I start to get confused, the reason is because I don't see the dramatic difference between orientations and rotations. I also don't understand why an orientation cannot be represented by a series of rotations... Also: The first thought towards this end would be to keep the orientation as a matrix. When the time comes to modify the orientation, we simply apply a transformation to this matrix, storing the result as the new current orientation. This means that every yaw, pitch, and roll applied to the current orientation will be relative to that current orientation. Which is precisely what we need. If the user applies a positive yaw, you want that yaw to rotate them relative to where they are current pointing, not relative to some fixed coordinate system. The concept, I understand, however I don't understand how if accumulating matrix transformations is a solution to this problem, how the code given in the previous page isn't just that. Here's the code: void display() { glClearColor(0.0f, 0.0f, 0.0f, 0.0f); glClearDepth(1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glutil::MatrixStack currMatrix; currMatrix.Translate(glm::vec3(0.0f, 0.0f, -200.0f)); currMatrix.RotateX(g_angles.fAngleX); DrawGimbal(currMatrix, GIMBAL_X_AXIS, glm::vec4(0.4f, 0.4f, 1.0f, 1.0f)); currMatrix.RotateY(g_angles.fAngleY); DrawGimbal(currMatrix, GIMBAL_Y_AXIS, glm::vec4(0.0f, 1.0f, 0.0f, 1.0f)); currMatrix.RotateZ(g_angles.fAngleZ); DrawGimbal(currMatrix, GIMBAL_Z_AXIS, glm::vec4(1.0f, 0.3f, 0.3f, 1.0f)); glUseProgram(theProgram); currMatrix.Scale(3.0, 3.0, 3.0); currMatrix.RotateX(-90); //Set the base color for this object. glUniform4f(baseColorUnif, 1.0, 1.0, 1.0, 1.0); glUniformMatrix4fv(modelToCameraMatrixUnif, 1, GL_FALSE, glm::value_ptr(currMatrix.Top())); g_pObject->Render("tint"); glUseProgram(0); glutSwapBuffers(); } To my understanding, isn't what he is doing (modifying a matrix on a stack) considered accumulating matrices, since the author combined all the individual rotation transformations into one matrix which is being stored on the top of the stack. My understanding of a matrix is that they are used to take a point which is relative to an origin (let's say... the model), and make it relative to another origin (the camera). I'm pretty sure this is a safe definition, however I feel like there is something missing which is blocking me from understanding this gimbal lock problem. One thing that doesn't make sense to me is: If a matrix determines the difference relative between two "spaces," how come a rotation around the Y axis for, let's say, roll, doesn't put the point in "roll space" which can then be transformed once again in relation to this roll... In other words shouldn't any further transformations to this point be in relation to this new "roll space" and therefore not have the rotation be relative to the previous "model space" which is causing the gimbal lock. That's why gimbal lock occurs right? It's because we are rotating the object around set X, Y, and Z axes rather than rotating the object around it's own, relative axes. Or am I wrong? Since apparently this code I linked in isn't an accumulation of matrix transformations can you please give an example of a solution using this method. So in summary: What is the difference between a rotation and an orientation? Why is the code linked in not an example of accumulation of matrix transformations? What is the real, specific purpose of a matrix, if I had it wrong? How could a solution to the gimbal lock problem be implemented using accumulation of matrix transformations? Also, as a bonus: Why are the transformations after the rotation still relative to "model space?" Another bonus: Am I wrong in the assumption that after a transformation, further transformations will occur relative to the current? Also, if it wasn't implied, I am using OpenGL, GLSL, C++, and GLM, so examples and explanations in terms of these are greatly appreciated, if not necessary. The more the detail the better! Thanks in advance...

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• How-to populate different select list content per table row

  - by frank.nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt: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;} A frequent requirement posted on the OTN forum is to render cells of a table column using instances of af:selectOneChoices with each af:selectOneChoice instance showing different list values. To implement this use case, the select list of the table column is populated dynamically from a managed bean for each row. The table's current rendered row object is accessible in the managed bean using the #{row} expression, where "row" is the value added to the table's var property. <af:table var="row">   ...   <af:column ...>     <af:selectOneChoice ...>         <f:selectItems value="#{browseBean.items}"/>     </af:selectOneChoice>   </af:column </af:table> The browseBean managed bean referenced in the code snippet above has a setItems and getItems method defined that is accessible from EL using the #{browseBean.items} expression. When the table renders, then the var property variable - the #{row} reference - is filled with the data object displayed in the current rendered table row. The managed bean getItems method returns a List<SelectItem>, which is the model format expected by the f:selectItems tag to populate the af:selectOneChoice list. public void setItems(ArrayList<SelectItem> items) {} //this method is executed for each table row public ArrayList<SelectItem> getItems() {   FacesContext fctx = FacesContext.getCurrentInstance();   ELContext elctx = fctx.getELContext();   ExpressionFactory efactory =          fctx.getApplication().getExpressionFactory();          ValueExpression ve =          efactory.createValueExpression(elctx, "#{row}", Object.class);      Row rw = (Row) ve.getValue(elctx);         //use one of the row attributes to determine which list to query and   //show in the current af:selectOneChoice list  // ...  ArrayList<SelectItem> alsi = new ArrayList<SelectItem>();  for( ... ){      SelectItem item = new SelectItem();        item.setLabel(...);        item.setValue(...);        alsi.add(item);   }   return alsi;} For better performance, the ADF Faces table stamps it data rows. Stamping means that the cell renderer component - af:selectOneChoice in this example - is instantiated once for the column and then repeatedly used to display the cell data for individual table rows. This however means that you cannot refresh a single select one choice component in a table to change its list values. Instead the whole table needs to be refreshed, rerunning the managed bean list query. Be aware that having individual list values per table row is an expensive operation that should be used only on small tables for Business Services with low latency data fetching (e.g. ADF Business Components and EJB) and with server side caching strategies for the queried data (e.g. storing queried list data in a managed bean in session scope).

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• YouTube Scalability Lessons

  - by Bertrand Matthelié

  @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }h2 { margin: 12pt 0cm 3pt; page-break-after: avoid; font-size: 14pt; font-family: "Times New Roman"; font-style: italic; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }span.Heading2Char { font-family: Calibri; font-weight: bold; font-style: italic; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Very interesting blog post by Todd Hoff at highscalability.com presenting “7 Years of YouTube Scalability Lessons in 30 min” based on a presentation from Mike Solomon, one of the original engineers at YouTube: …. The key takeaway away of the talk for me was doing a lot with really simple tools. While many teams are moving on to more complex ecosystems, YouTube really does keep it simple. They program primarily in Python, use MySQL as their database, they’ve stuck with Apache, and even new features for such a massive site start as a very simple Python program. That doesn’t mean YouTube doesn’t do cool stuff, they do, but what makes everything work together is more a philosophy or a way of doing things than technological hocus pocus. What made YouTube into one of the world’s largest websites? Read on and see... Stats @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } 4 billion Views a day 60 hours of video is uploaded every minute 350+ million devices are YouTube enabled Revenue double in 2010 The number of videos has gone up 9 orders of magnitude and the number of developers has only gone up two orders of magnitude. 1 million lines of Python code Stack @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Python - most of the lines of code for YouTube are still in Python. Everytime you watch a YouTube video you are executing a bunch of Python code. Apache - when you think you need to get rid of it, you don’t. Apache is a real rockstar technology at YouTube because they keep it simple. Every request goes through Apache. Linux - the benefit of Linux is there’s always a way to get in and see how your system is behaving. No matter how bad your app is behaving, you can take a look at it with Linux tools like strace and tcpdump. MySQL - is used a lot. When you watch a video you are getting data from MySQL. Sometime it’s used a relational database or a blob store. It’s about tuning and making choices about how you organize your data. Vitess- a  new project released by YouTube, written in Go, it’s a frontend to MySQL. It does a lot of optimization on the fly, it rewrites queries and acts as a proxy. Currently it serves every YouTube database request. It’s RPC based. Zookeeper - a distributed lock server. It’s used for configuration. Really interesting piece of technology. Hard to use correctly so read the manual Wiseguy - a CGI servlet container. Spitfire - a templating system. It has an abstract syntax tree that let’s them do transformations to make things go faster. Serialization formats - no matter which one you use, they are all expensive. Measure. Don’t use pickle. Not a good choice. Found protocol buffers slow. They wrote their own BSON implementation, which is 10-15 time faster than the one you can download. ...Contiues. Read the blog Watch the video

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• Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

  - by MarkPearl

  After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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• Problem with deleting table rows using ctrl+a for row selection

  - by Frank Nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt: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;} The following code is commonly shown and documented for how to access the row key of selected table rows in an ADF Faces table configured for multi row selection. public void onRemoveSelectedTableRows(ActionEvent actionEvent) {    RichTable richTable = … get access to your table instance …    CollectionModel cm =(CollectionModel)richTable.getValue();    RowKeySet rowKeySet = (RowKeySet)richTable.getSelectedRowKeys();             for (Object key : rowKeySet) {       richTable.setRowKey(key);       JUCtrlHierNodeBinding rowData = (JUCtrlHierNodeBinding)cm.getRowData();       // do something with rowData e.g.update, print, copy   }    //optional, if you changed data, refresh the table         AdfFacesContext adfFacesContext = AdfFacesContext.getCurrentInstance(); adfFacesContext.addPartialTarget(richTable);   return null; } The code shown above works for 99.5 % of all use cases that deal with multi row selection enabled ADF Faces tables, except for when users use the ctrl+a key to mark all rows for delete. Just to make sure I am clear: if you use ctrl+a to mark rows to perform any other operation on them – like bulk updating all rows for a specific attribute – then this works with the code shown above. Even for bulk row delete, any other mean of row selection (shift+click and multiple ctrl+click) works like a charm and the rows are deleted. So apparently it is the use of ctrl+a that causes the problem when deleting multiple rows of an ADF Faces table. To implement code that works for all table selection use cases, including the one to delete all table rows in one go, you use the code shown below. public void onRemoveSelectedTableRows(ActionEvent actionEvent) {   RichTable richTable = … get access to your table instance …   CollectionModel cm = (CollectionModel)richTable.getValue();   RowKeySet rowKeySet = (RowKeySet)richTable.getSelectedRowKeys();   Object[] rowKeySetArray = rowKeySet.toArray();      for (Object key : rowKeySetArray){               richTable.setRowKey(key);     JUCtrlHierNodeBinding rowData = (JUCtrlHierNodeBinding)cm.getRowData();                              rowData.getRow().remove();   }   AdfFacesContext adfFacesContext = AdfFacesContext.getCurrentInstance();          adfFacesContext.addPartialTarget(richTable); }

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• SQLIO Writes

  - by Grant Fritchey

  SQLIO is a fantastic utility for testing the abilities of the disks in your system. It has a very unfortunate name though, since it's not really a SQL Server testing utility at all. It really is a disk utility. They ought to call it DiskIO because they'd get more people using I think. Anyway, branding is not the point of this blog post. Writes are the point of this blog post. SQLIO works by slamming your disk. It performs as mean reads as it can or it performs as many writes as it can depending on how you've configured your tests. There are much smarter people than me who will get into all the various types of tests you should run. I'd suggest reading a bit of what Jonathan Kehayias (blog|twitter) has to say or wade into Denny Cherry's (blog|twitter) work. They're going to do a better job than I can describing all the benefits and mechanisms around using this excellent piece of software. My concerns are very focused. I needed to set up a series of tests to see how well our product SQL Storage Compress worked. I wanted to know the effects it would have on a system, the disk for sure, but also memory and CPU. How to stress the system? SQLIO of course. But when I set it up and ran it, following the documentation that comes with it, I was seeing better than 99% compression on the files. Don't get me wrong. Our product is magnificent, wonderful, all things great and beautiful, gets you coffee in the morning and is made mostly from bacon. But 99% compression. No, it's not that good. So what's up? Well, it's the configuration. The default mechanism is to load up a file, something large that will overwhelm your disk cache. You're instructed to load the file with a character 0x0. I never got a computer science degree. I went to film school. Because of this, I didn't memorize ASCII tables so when I saw this, I thought it was zero's or something. Nope. It's NULL. That's right, you're making a very large file, but you're filling it with NULL values. That's actually ok when all you're testing is the disk sub-system. But, when you want to test a compression and decompression, that can be an issue. I got around this fairly quickly. Instead of generating a file filled with NULL values, I just copied a database file for my tests. And to test it with SQL Storage Compress, I used a database file that had already been run through compression (about 40% compression on that file if you're interested). Now the reads were taken care of. I am seeing very realistic performance from decompressing the information for reads through SQLIO. But what about writes? Well, the issue is, what does SQLIO write? I don't have access to the code. But I do have access to the results. I did two different tests, just to be sure of what I was seeing. First test, use the .DAT file as described in the documentation. I opened the .DAT file after I was done with SQLIO, using WordPad. Guess what? It's a giant file full of air. SQLIO writes NULL values. What does that do to compression? I did the test again on a copy of an uncompressed database file. Then I ran the original and the SQLIO modified copy through ZIP to see what happened. I got better than 99% compression out of the SQLIO modified file (original file of 624,896kb went to 275,871kb compressed, after SQLIO it went to 608kb compressed). So, what does SQLIO write? It writes air. If you're trying to test it with compression or maybe some other type of file storage mechanism like dedupe, you need to know this because your tests really won't be valid. Should I find some other mechanism for testing? Yeah, if all I'm interested in is establishing performance to my own satisfaction, yes. But, I want to be able to compare my results with other people's results and we all need to be using the same tool in order for that to happen. SQLIO is the common mechanism that most people I know use to establish disk performance behavior. It'd be better if we could get SQLIO to do writes in some other fashion. Oh, and before I go, I get to brag a bit. Measuring IOPS, SQL Storage Compress outperforms my disk alone by about 30%.

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• Rebuilding CoasterBuzz, Part II: Hot data objects

  - by Jeff

  This is the second post, originally from my personal blog, in a series about rebuilding one of my Web sites, which has been around for 12 years. More: Part I: Evolution, and death to WCF After the rush to get moving on stuff, I temporarily lost interest. I went almost two weeks without touching the project, in part because the next thing on my backlog was doing up a bunch of administrative pages. So boring. Unfortunately, because most of the site's content is user-generated, you need some facilities for editing data. CoasterBuzz has a database full of amusement parks and roller coasters. The entities enjoy the relationships that you would expect, though they're further defined by "instances" of a coaster, to define one that has moved between parks as one, with different names and operational dates. And of course, there are pictures and news items, too. It's not horribly complex, except when you have to account for a name change and display just the newest name. In all previous versions, data access was straight SQL. As so much of the old code was rooted in 2003, with some changes in 2008, there wasn't much in the way of ORM frameworks going on then. Let me rephrase that, I mostly wasn't interested in ORM's. Since that time, I used a little LINQ to SQL in some projects, and a whole bunch of nHibernate while at Microsoft. Through all of that experience, I have to admit that these frameworks are often a bigger pain in the ass than not. They're great for basic crud operations, but when you start having all kinds of exotic relationships, they get difficult, and generate all kinds of weird SQL under the covers. The black box can quickly turn into a black hole. Sometimes you end up having to build all kinds of new expertise to do things "right" with a framework. Still, despite my reservations, I used the newer version of Entity Framework, with the "code first" modeling, in a science project and I really liked it. Since it's just a right-click away with NuGet, I figured I'd give it a shot here. My initial effort was spent defining the context class, which requires a bit of work because I deviate quite a bit from the conventions that EF uses, starting with table names. Then throw some partial querying of certain tables (where you'll find image data), and you're splitting tables across several objects (navigation properties). I won't go into the details, because these are all things that are well documented around the Internet, but there was a minor learning curve there. The basics of reading data using EF are fantastic. For example, a roller coaster object has a park associated with it, as well as a number of instances (if it was ever relocated), and there also might be a big banner image for it. This is stupid easy to use because it takes one line of code in your repository class, and by the time you pass it to the view, you have a rich object graph that has everything you need to display stuff. Likewise, editing simple data is also, well, simple. For this goodness, thank the ASP.NET MVC framework. The UpdateModel() method on the controllers is very elegant. Remember the old days of assigning all kinds of properties to objects in your Webforms code-behind? What a time consuming mess that used to be. Even if you're not using an ORM tool, having hydrated objects come off the wire is such a time saver. Not everything is easy, though. When you have to persist a complex graph of objects, particularly if they were composed in the user interface with all kinds of AJAX elements and list boxes, it's not just a simple matter of submitting the form. There were a few instances where I ended up going back to "old-fashioned" SQL just in the interest of time. It's not that I couldn't do what I needed with EF, it's just that the efficiency, both my own and that of the generated SQL, wasn't good. Since EF context objects expose a database connection object, you can use that to do the old school ADO.NET stuff you've done for a decade. Using various extension methods from POP Forums' data project, it was a breeze. You just have to stick to your decision, in this case. When you start messing with SQL directly, you can't go back in the same code to messing with entities because EF doesn't know what you're changing. Not really a big deal. There are a number of take-aways from using EF. The first is that you write a lot less code, which has always been a desired outcome of ORM's. The other lesson, and I particularly learned this the hard way working on the MSDN forums back in the day, is that trying to retrofit an ORM framework into an existing schema isn't fun at all. The CoasterBuzz database isn't bad, but there are design decisions I'd make differently if I were starting from scratch. Now that I have some of this stuff done, I feel like I can start to move on to the more interesting things on the backlog. There's a lot to do, but at least it's fun stuff, and not more forms that will be used infrequently.

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• OIM 11g - Multi Valued attribute reconciliation of a child form

  - by user604275

  This topic gives a brief description on how we can do reconciliation of a child form attribute which is also multi valued from a flat file . The format of the flat file is (an example): ManagementDomain1|Entitlement1|DIRECTORY SERVER,EMAIL ManagementDomain2|Entitlement2|EMAIL PROVIDER INSTANCE - UMS,EMAIL VERIFICATION In OIM there will be a parent form for fields Management domain and Entitlement.Reconciliation will assign Servers ( which are multi valued) to corresponding Management  Domain and Entitlement .In the flat file , multi valued fields are seperated by comma(,). In the design console, Create a form with 'Server Name' as a field and make it a child form . Open the corresponding Resource Object and add this field for reconcilitaion.While adding , choose 'Multivalued' check box. (please find attached screen shot on how to add it , Child Table.docx) Open process definiton and add child form fields for recociliation. Please click on the 'Create Reconcilitaion Profile' buttton on the resource object tab. The API methods used for child form reconciliation are : 1.           reconEventKey =   reconOpsIntf.createReconciliationEvent(resObjName, reconData,                                                            false); ·                                    ‘False’  here tells that we are creating the recon for a child table . 2.               2.       reconOpsIntf.providingAllMultiAttributeData(reconEventKey, RECON_FIELD_IN_RO, true);                RECON_FIELD_IN_RO is the field that we added in the Resource Object while adding for reconciliation, please refer the screen shot) 3.    reconOpsIntf.addDirectBulkMultiAttributeData(reconEventKey,RECON_FIELD_IN_RO, bulkChildDataMapList);                 bulkChildDataMapList  is coded as below :                 List<Map> bulkChildDataMapList = new ArrayList<Map>();                   for (int i = 0; i < stokens.length; i++) {                            Map<String, String> attributeMap = new HashMap<String, String>();                           String serverName = stokens[i].toUpperCase();                           attributeMap.put("Server Name", stokens[i]);                           bulkChildDataMapList.add(attributeMap);                         } 4                  4.       reconOpsIntf.finishReconciliationEvent(reconEventKey); 5.       reconOpsIntf.processReconciliationEvent(reconEventKey); Now, we have to register the plug-in, import metadata into MDS and then create a scheduled job to execute which will run the reconciliation.

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• Developing Schema Compare for Oracle (Part 6): 9i Query Performance

  - by Simon Cooper

  All throughout the EAP and beta versions of Schema Compare for Oracle, our main request was support for Oracle 9i. After releasing version 1.0 with support for 10g and 11g, our next step was then to get version 1.1 of SCfO out with support for 9i. However, there were some significant problems that we had to overcome first. This post will concentrate on query execution time. When we first tested SCfO on a 9i server, after accounting for various changes to the data dictionary, we found that database registration was taking a long time. And I mean a looooooong time. The same database that on 10g or 11g would take a couple of minutes to register would be taking upwards of 30 mins on 9i. Obviously, this is not ideal, so a poke around the query execution plans was required. As an example, let's take the table population query - the one that reads ALL_TABLES and joins it with a few other dictionary views to get us back our list of tables. On 10g, this query takes 5.6 seconds. On 9i, it takes 89.47 seconds. The difference in execution plan is even more dramatic - here's the (edited) execution plan on 10g: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 108K| 939 || 1 | SORT ORDER BY | | 108K| 939 || 2 | NESTED LOOPS OUTER | | 108K| 938 ||* 3 | HASH JOIN RIGHT OUTER | | 103K| 762 || 4 | VIEW | ALL_EXTERNAL_LOCATIONS | 2058 | 3 ||* 20 | HASH JOIN RIGHT OUTER | | 73472 | 759 || 21 | VIEW | ALL_EXTERNAL_TABLES | 2097 | 3 ||* 34 | HASH JOIN RIGHT OUTER | | 39920 | 755 || 35 | VIEW | ALL_MVIEWS | 51 | 7 || 58 | NESTED LOOPS OUTER | | 39104 | 748 || 59 | VIEW | ALL_TABLES | 6704 | 668 || 89 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2025 | 5 || 106 | VIEW | ALL_PART_TABLES | 277 | 11 |------------------------------------------------------------------------------- And the same query on 9i: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 16P| 55G|| 1 | SORT ORDER BY | | 16P| 55G|| 2 | NESTED LOOPS OUTER | | 16P| 862M|| 3 | NESTED LOOPS OUTER | | 5251G| 992K|| 4 | NESTED LOOPS OUTER | | 4243M| 2578 || 5 | NESTED LOOPS OUTER | | 2669K| 1440 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 ||* 50 | VIEW PUSHED PREDICATE | ALL_TAB_COMMENTS | 2043 | ||* 66 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_TABLES | 1777K| ||* 80 | VIEW PUSHED PREDICATE | ALL_EXTERNAL_LOCATIONS | 1744K| ||* 96 | VIEW | ALL_PART_TABLES | 852K| |------------------------------------------------------------------------------- Have a look at the cost column. 10g's overall query cost is 939, and 9i is 55,000,000,000 (or more precisely, 55,496,472,769). It's also having to process far more data. What on earth could be causing this huge difference in query cost? After trawling through the '10g New Features' documentation, we found item 1.9.2.21. Before 10g, Oracle advised that you do not collect statistics on data dictionary objects. From 10g, it advised that you do collect statistics on the data dictionary; for our queries, Oracle therefore knows what sort of data is in the dictionary tables, and so can generate an efficient execution plan. On 9i, no statistics are present on the system tables, so Oracle has to use the Rule Based Optimizer, which turns most LEFT JOINs into nested loops. If we force 9i to use hash joins, like 10g, we get a much better plan: -------------------------------------------------------------------------------| Id | Operation | Name | Bytes | Cost |-------------------------------------------------------------------------------| 0 | SELECT STATEMENT | | 7587K| 3704 || 1 | SORT ORDER BY | | 7587K| 3704 ||* 2 | HASH JOIN OUTER | | 7587K| 822 ||* 3 | HASH JOIN OUTER | | 5262K| 616 ||* 4 | HASH JOIN OUTER | | 2980K| 465 ||* 5 | HASH JOIN OUTER | | 710K| 432 ||* 6 | HASH JOIN OUTER | | 398K| 302 || 7 | VIEW | ALL_TABLES | 342K| 276 || 29 | VIEW | ALL_MVIEWS | 51 | 20 || 50 | VIEW | ALL_PART_TABLES | 852K| 104 || 78 | VIEW | ALL_TAB_COMMENTS | 2043 | 14 || 93 | VIEW | ALL_EXTERNAL_LOCATIONS | 1744K| 31 || 106 | VIEW | ALL_EXTERNAL_TABLES | 1777K| 28 |------------------------------------------------------------------------------- That's much more like it. This drops the execution time down to 24 seconds. Not as good as 10g, but still an improvement. There are still several problems with this, however. 10g introduced a new join method - a right outer hash join (used in the first execution plan). The 9i query optimizer doesn't have this option available, so forcing a hash join means it has to hash the ALL_TABLES table, and furthermore re-hash it for every hash join in the execution plan; this could be thousands and thousands of rows. And although forcing hash joins somewhat alleviates this problem on our test systems, there's no guarantee that this will improve the execution time on customers' systems; it may even increase the time it takes (say, if all their tables are partitioned, or they've got a lot of materialized views). Ideally, we would want a solution that provides a speedup whatever the input. To try and get some ideas, we asked some oracle performance specialists to see if they had any ideas or tips. Their recommendation was to add a hidden hook into the product that allowed users to specify their own query hints, or even rewrite the queries entirely. However, we would prefer not to take that approach; as well as a lot of new infrastructure & a rewrite of the population code, it would have meant that any users of 9i would have to spend some time optimizing it to get it working on their system before they could use the product. Another approach was needed. All our population queries have a very specific pattern - a base table provides most of the information we need (ALL_TABLES for tables, or ALL_TAB_COLS for columns) and we do a left join to extra subsidiary tables that fill in gaps (for instance, ALL_PART_TABLES for partition information). All the left joins use the same set of columns to join on (typically the object owner & name), so we could re-use the hash information for each join, rather than re-hashing the same columns for every join. To allow us to do this, along with various other performance improvements that could be done for the specific query pattern we were using, we read all the tables individually and do a hash join on the client. Fortunately, this 'pure' algorithmic problem is the kind that can be very well optimized for expected real-world situations; as well as storing row data we're not using in the hash key on disk, we use very specific memory-efficient data structures to store all the information we need. This allows us to achieve a database population time that is as fast as on 10g, and even (in some situations) slightly faster, and a memory overhead of roughly 150 bytes per row of data in the result set (for schemas with 10,000 tables in that means an extra 1.4MB memory being used during population). Next: fun with the 9i dictionary views.

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• What Counts for A DBA: Observant

  - by drsql

  When walking up to the building where I work, I can see CCTV cameras placed here and there for monitoring access to the building. We are required to wear authorization badges which could be checked at any time. Do we have enemies?  Of course! No one is 100% safe; even if your life is a fairy tale, there is always a witch with an apple waiting to snack you into a thousand years of slumber (or at least so I recollect from elementary school.) Even Little Bo Peep had to keep a wary lookout.    We nerdy types (or maybe it was just me?) generally learned on the school playground to keep an eye open for unprovoked attack from simpler, but more muscular souls, and take steps to avoid messy confrontations well in advance. After we’d apprehensively negotiated adulthood with varying degrees of success, these skills of watching for danger, and avoiding it,  translated quite well to the technical careers so many of us were destined for. And nowhere else is this talent for watching out for irrational malevolence so appropriate as in a career as a production DBA.   It isn’t always active malevolence that the DBA needs to watch out for, but the even scarier quirks of common humanity.  A large number of the issues that occur in the enterprise happen just randomly or even just one time ever in a spurious manner, like in the case where a person decided to download the entire MSDN library of software, cross join every non-indexed billion row table together, and simultaneously stream the HD feed of 5 different sporting events, making the network access slow while the corporate online sales just started. The decent DBA team, like the going, gets tough under such circumstances. They spring into action, checking all of the sources of active information, observes the issue is no longer happening now, figures that either it wasn’t the database’s fault and that the reboot of the whatever device on the network fixed the problem.  This sort of reactive support is good, and will be the initial reaction of even excellent DBAs, but it is not the end of the story if you really want to know what happened and avoid getting called again when it isn’t even your fault.   When fires start raging within the corporate software forest, the DBA’s instinct is to actively find a way to douse the flames and get back to having no one in the company have any idea who they are.  Even better for them is to find a way of killing a potential problem while the fires are small, long before they can be classified as raging. The observant DBA will have already been monitoring the server environment for months in advance.  Most troubles, such as disk space and security intrusions, can be predicted and dealt with by alerting systems, whereas other trouble can come out of the blue and requires a skill of observing ongoing conditions and noticing inexplicable changes that could signal an emerging problem.  You can’t automate the DBA, because the bankable skill of a DBA is in detecting the early signs of unexpected problems, and working out how to deal with them before anyone else notices them.    To achieve this, the DBA will check the situation as it is currently happening,  and in many cases is likely to have been the person who submitted the problem to the level 1 support person in the first place, just to let the support team know of impending issues (always well received, I tell you what!). Database and host computer settings, configurations, and even critical data might be profiled and captured for later comparisons. He’ll use Monitoring tools, built-in, commercial (Not to be too crassly commercial or anything, but there is one such tool is SQL Monitor) and lots of homebrew monitoring tools to monitor for problems and changes in the server environment.   You will know that you have it right when a support call comes in and you can look at your monitoring tools and quickly respond that “response time is well within the normal range, the query that supports the failing interface works perfectly and has actually only been called 67% as often as normal, so I am more than willing to help diagnose the problem, but it isn’t the database server’s fault and is probably a client or networking slowdown causing the interface to be used less frequently than normal.” And that is the best thing for any DBA to observe…

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• Understanding implementation of glu.PickMatrix()

  - by stoney78us

  I am working on an OpenGL project which requires object selection feature. I use OpenTK framework to do this; however OpenTK doesn't support glu.PickMatrix() method to define the picking region. I ended up googling its implementation and here is what i got: void GluPickMatrix(double x, double y, double deltax, double deltay, int[] viewport) { if (deltax <= 0 || deltay <= 0) { return; } GL.Translate((viewport[2] - 2 * (x - viewport[0])) / deltax, (viewport[3] - 2 * (y - viewport[1])) / deltay, 0); GL.Scale(viewport[2] / deltax, viewport[3] / deltay, 1.0); } I totally fail to understand this piece of code. Moreover, this doesn't work with my following code sample: //selectbuffer private int[] _selectBuffer = new int[512]; private void Init() { float[] triangleVertices = new float[] { 0.0f, 1.0f, 0.0f, -1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f }; float[] _triangleColors = new float[] { 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f }; GL.GenBuffers(2, _vBO); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleVertices.Length), _triangleVertices, BufferUsageHint.StaticDraw); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[1]); GL.BufferData(BufferTarget.ArrayBuffer, new IntPtr(sizeof(float) * _triangleColors.Length), _triangleColors, BufferUsageHint.StaticDraw); GL.ColorPointer(3, ColorPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.ColorArray); //Selectbuffer set up GL.SelectBuffer(512, _selectBuffer); } private void glControlWindow_Paint(object sender, PaintEventArgs e) { GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); float[] eyes = { 0.0f, 0.0f, -10.0f }; float[] target = { 0.0f, 0.0f, 0.0f }; Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); //45 degree = 0.785398163 rads Matrix4 view = Matrix4.LookAt(eyes[0], eyes[1], eyes[2], target[0], target[1], target[2], 0, 1, 0); Matrix4 model = Matrix4.Identity; Matrix4 MV = view * model; //First Clear Buffers GL.Clear(ClearBufferMask.ColorBufferBit); GL.Clear(ClearBufferMask.DepthBufferBit); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); GL.LoadIdentity(); GL.LoadMatrix(ref MV); GL.Viewport(0, 0, glControlWindow.Width, glControlWindow.Height); GL.Enable(EnableCap.DepthTest); //Enable correct Z Drawings GL.DepthFunc(DepthFunction.Less); //Enable correct Z Drawings GL.MatrixMode(MatrixMode.Modelview); GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); DrawTriangle(); GL.PopMatrix(); //Finally... GraphicsContext.CurrentContext.VSync = true; //Caps frame rate as to not over run GPU glControlWindow.SwapBuffers(); //Takes from the 'GL' and puts into control } private void DrawTriangle() { GL.BindBuffer(BufferTarget.ArrayBuffer, _vBO[0]); GL.VertexPointer(3, VertexPointerType.Float, 0, 0); GL.EnableClientState(ArrayCap.VertexArray); GL.DrawArrays(BeginMode.Triangles, 0, 3); GL.DisableClientState(ArrayCap.VertexArray); } //mouse click event implementation private void glControlWindow_MouseClick(object sender, System.Windows.Forms.MouseEventArgs e) { //Enter Select mode. Pretend drawing. GL.RenderMode(RenderingMode.Select); int[] viewport = new int[4]; GL.GetInteger(GetPName.Viewport, viewport); GL.PushMatrix(); GL.MatrixMode(MatrixMode.Projection); GL.LoadIdentity(); GluPickMatrix(e.X, e.Y, 5, 5, viewport); Matrix4 projection = Matrix4.CreatePerspectiveFieldOfView(0.785398163f, 4.0f / 3.0f, 0.1f, 100f); // this projection matrix is the same as one in glControlWindow_Paint method. GL.LoadMatrix(ref projection); GL.MatrixMode(MatrixMode.Modelview); int i = 0; int hits; GL.PushMatrix(); GL.Translate(3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); i++; GL.PushMatrix(); GL.Translate(-3.0f, 0.0f, 0.0f); GL.PushName(i); DrawTriangle(); GL.PopName(); GL.PopMatrix(); hits = GL.RenderMode(RenderingMode.Render); .....hits processing code goes here... GL.PopMatrix(); glControlWindow.Invalidate(); } I expect to get only one hit everytime i click inside a triangle, but i always get 2 no matter where i click. I suspect there is something wrong with the implementation of the GluPickMatrix, I haven't figured out yet.

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• Copies of GameScene created when called additional times

  - by Orin MacGregor

  I have a game with a level select managed by a SceneManager, which basically just uses ReplaceScene. The first time I load a level everything works fine. On subsequent calls, for example: completing the level and continuing to the next, things blow up. The level loads fine, but when I try to pan the map or try to move the player the game crashes. Debugging through I found that there are multiple occurrences of self and related children like player and mapLayer. As a test, I put this code in my ccTouchesBegan: NSLog(@"test %i", [self retainCount]); The first time a level is loaded, it gives: test 2 The second time I load a level it gives: test 2 test 1 as in it spits out both values by looping through twice, not just appending an output to the last. It continues with this pattern for each subsequent load. So the third time will give 2 1 1. Particular code that causes the game to crash involve calling _tileMap.tileSize because there is a second GameScene with a tileMap that was supposedly destroyed, so it has tileSize and mapSize of 0. I noticed dealloc doesn't really ever get called, so I tried to manage some things with -(void) onExit -(void) onExit { [self unscheduleAllSelectors]; [_player stopAllActions]; //stop any animations just in case. normally handled in ccTouchesEnded [self removeAllChildrenWithCleanup:YES]; } I never replace the GameScene while I'm in a GameScene; if the level is completed it goes to a GameOver scene, or I use a back button that goes to the LevelSelect scene. This is [the relevant parts of] my init, in case something like the adding of children matters: -(id) init { _mapLayer = [CCLayer node]; //load data for level GameData *gameData = [GameDataParser loadData]; int selectedChapter = gameData.selectedChapter; int selectedLevel = gameData.selectedLevel; Levels *chapterLevels = [LevelParser loadLevelsForChapter:selectedChapter]; //loop until we get selected level, then do stuff for (Level *level in chapterLevels.levels) { if (level.number == selectedLevel) { //load the level map _tileMap = [CCTMXTiledMap tiledMapWithTMXFile:level.file]; } } _background = [_tileMap layerNamed:@"Background"]; _foreground = [_tileMap layerNamed:@"Foreground"]; _meta = [_tileMap layerNamed:@"Meta"]; _meta.visible = NO; //initialize Spawn Point object and place player there CCTMXObjectGroup *objects = [_tileMap objectGroupNamed:@"Objects"]; NSAssert(objects != nil, @"'Objects' object group not found"); NSMutableDictionary *spawnPoint = [objects objectNamed:@"SpawnPoint"]; NSAssert(spawnPoint != nil, @"SpawnPoint object not found"); int x = [[spawnPoint valueForKey:@"x"] intValue] / retinaScaling; int y = [[spawnPoint valueForKey:@"y"] intValue] / retinaScaling; //setup animations [[CCSpriteFrameCache sharedSpriteFrameCache] addSpriteFramesWithFile:@"MouseRightAnim_24x21.plist"]; CCSpriteBatchNode *spriteSheet = [CCSpriteBatchNode batchNodeWithFile:@"MouseRightAnim_24x21.png"]; [_mapLayer addChild:spriteSheet z:1]; NSMutableArray *rightAnimFrames = [NSMutableArray array]; for(int i = 1; i <= 3; ++i) { [rightAnimFrames addObject: [[CCSpriteFrameCache sharedSpriteFrameCache] spriteFrameByName: [NSString stringWithFormat:@"MouseRight%d_24x21.png", i]]]; } CCAnimation *rightAnim = [CCAnimation animationWithSpriteFrames:rightAnimFrames delay:0.1f]; self.player = [CCSprite spriteWithSpriteFrameName:@"MouseRight2_24x21.png"]; _player.position = ccp(x, y); self.rightAction = [CCRepeatForever actionWithAction:[CCAnimate actionWithAnimation:rightAnim]]; rightAnim.restoreOriginalFrame = NO; [spriteSheet addChild:_player]; //get map size in pixels mapHeight = _tileMap.contentSize.height; mapWidth = _tileMap.contentSize.width; //setup defaults //this value works well for the calculation later, trial and error really distance = 150; lastGoodDistance = 150; mapScale = 1; [self setViewpointCenter:_player.position]; [_mapLayer addChild:_tileMap]; [self addChild:_mapLayer z:-1]; self.isTouchEnabled = YES; } return self; } And here's the SceneManager code for replacing scenes: +(void) goGameScene { CCLayer *gameLayer = [GameScene node]; [SceneManager go:gameLayer:[GameHUD node]]; } //this is what every call looks like besides the GameScene one above +(void) goLevelSelect { [SceneManager go:[LevelSelect node]:nil]; } +(void) go:(CCLayer *)layer: (CCLayer *)hudLayer { CCDirector *director = [CCDirector sharedDirector]; CCScene *newScene = [SceneManager wrap:layer:hudLayer]; if ([director runningScene]) { [director replaceScene:newScene]; } else { [director runWithScene:newScene]; } } +(CCScene *) wrap:(CCLayer *)layer: (CCLayer *)hudLayer { CCScene *newScene = [CCScene node]; [newScene addChild: layer]; if (hudLayer != nil) { [newScene addChild: hudLayer z:1]; } return newScene; } Any ideas why I'm getting these fatal artifacts? I'm hoping this isn't considered too localized since it basically combines 3 tutorials that anyone could end up following. (Ray Wenderlich Animations, Tim Roadley Scene Manager, Pan and Zoom with Tiled Maps.

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• Adaptive Connections For ADFBC

  - by Duncan Mills

  Some time ago I wrote an article on Adaptive Bindings showing how the pageDef for a an ADF UI does not have to be wedded to a fixed data control or collection / View Object. This article has proved pretty popular, so as a follow up I wanted to cover another "Adaptive" feature of your ADF applications, the ability to make multiple different connections from an Application Module, at runtime. Now, I'm sure you'll be aware that if you define your application to use a data-source rather than a hard-coded JDBC connection string, then you have the ability to change the target of that data-source after deployment to point to a different database. So that's great, but the reality of that is that this single connection is effectively fixed within the application right?  Well no, this it turns out is a common misconception. To be clear, yes a single instance of an ADF Application Module is associated with a single connection but there is nothing to stop you from creating multiple instances of the same Application Module within the application, all pointing at different connections.  If fact this has been possible for a long time using a custom extension point with code that which extends oracle.jbo.http.HttpSessionCookieFactory. This approach, however, involves writing code and no-one likes to write any more code than they need to, so, is there an easier way? Yes indeed.  It is in fact  a little publicized feature that's available in all versions of 11g, the ELEnvInfoProvider. What Does it Do?  The ELEnvInfoProvider  is  a pre-existing class (the full path is  oracle.jbo.client.ELEnvInfoProvider) which you can plug into your ApplicationModule configuration using the jbo.envinfoprovider property. Visuallty you can set this in the editor, or you can also set it directly in the bc4j.xcfg (see below for an example) . Once you have plugged in this envinfoprovider, here's the fun bit, rather than defining the hard-coded name of a datasource instead you can plug in a EL expression for the connection to use.  So what's the benefit of that? Well it allows you to defer the selection of a connection until the point in time that you instantiate the AM. To define the expression itself you'll need to do a couple of things: First of all you'll need a managed bean of some sort – e.g. a sessionScoped bean defined in your ViewController project. This will need a getter method that returns the name of the connection. Now this connection itself needs to be defined in your Application Server, and can be managed through Enterprise Manager, WLST or through MBeans. (You may need to read the documentation [http://docs.oracle.com/cd/E28280_01/web.1111/b31974/deployment_topics.htm#CHDJGBDD] here on how to configure connections at runtime if you're not familiar with this)   The EL expression (e.g. ${connectionManager.connection} is then defined in the configuration by editing the bc4j.xcfg file (there is a hyperlink directly to this file on the configuration editing screen in the Application Module editor). You simply replace the hardcoded JDBCName value with the expression.  So your cfg file would end up looking something like this (notice the reference to the ELEnvInfoProvider that I talked about earlier) <BC4JConfig version="11.1" xmlns="http://xmlns.oracle.com/bc4j/configuration">   <AppModuleConfigBag ApplicationName="oracle.demo.model.TargetAppModule">   <AppModuleConfig DeployPlatform="LOCAL"  JDBCName="${connectionManager.connection}" jbo.project="oracle.demo.model.Model" name="TargetAppModuleLocal" ApplicationName="oracle.demo.model.TargetAppModule"> <AM-Pooling jbo.doconnectionpooling="true"/> <Database jbo.locking.mode="optimistic">       <Security AppModuleJndiName="oracle.demo.model.TargetAppModule"/>    <Custom jbo.envinfoprovider="oracle.jbo.client.ELEnvInfoProvider"/> </AppModuleConfig> </AppModuleConfigBag> </BC4JConfig> Still Don't Quite Get It? So far you might be thinking, well that's fine but what difference does it make if the connection is resolved "just in time" rather than up front and changed as required through Enterprise Manager? Well a trivial example would be where you have a single application deployed to your application server, but for different users you want to connect to different databases. Because, the evaluation of the connection is deferred until you first reference the AM you have a decision point that can take the user identity into account. However, think about it for a second.  Under what circumstances does a new AM get instantiated? Well at the first reference of the AM within the application yes, but also whenever a Task Flow is entered -  if the data control scope for the Task Flow is ISOLATED.  So the reality is, that on a single screen you can embed multiple Task Flows, all of which are pointing at different database connections concurrently. Hopefully you'll find this feature useful, let me know... 

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• Part 4 of 4 : Tips/Tricks for Silverlight Developers.

  - by mbcrump

  Part 1 | Part 2 | Part 3 | Part 4 I wanted to create a series of blog post that gets right to the point and is aimed specifically at Silverlight Developers. The most important things I want this series to answer is : What is it?  Why do I care? How do I do it? I hope that you enjoy this series. Let’s get started: Tip/Trick #16) What is it? Find out version information about Silverlight and which WebKit it is using by going to http://issilverlightinstalled.com/scriptverify/. Why do I care? I’ve had those users that its just easier to give them a site and say copy/paste the line that says User Agent in order to troubleshoot a Silverlight problem. I’ve also been debugging my own Silverlight applications and needed an easy way to determine if the plugin is disabled or not. How do I do it: Simply navigate to http://issilverlightinstalled.com/scriptverify/ and hit the Verify button. An example screenshot is located below: Results from Chrome 7 Results from Internet Explorer 8 (With Silverlight Disabled) Tip/Trick #17) What is it? Use Lambdas whenever you can. Why do I care?  It is my personal opinion that code is easier to read using Lambdas after you get past the syntax. How do I do it: For example: You may write code like the following: void MainPage_Loaded(object sender, RoutedEventArgs e) { //Check and see if we have a newer .XAP file on the server Application.Current.CheckAndDownloadUpdateAsync(); Application.Current.CheckAndDownloadUpdateCompleted += new CheckAndDownloadUpdateCompletedEventHandler(Current_CheckAndDownloadUpdateCompleted); } void Current_CheckAndDownloadUpdateCompleted(object sender, CheckAndDownloadUpdateCompletedEventArgs e) { if (e.UpdateAvailable) { MessageBox.Show( "An update has been installed. To see the updates please exit and restart the application"); } } To me this style forces me to look for the other Method to see what the code is actually doing. The style located below is much easier to read in my opinion and does the exact same thing. void MainPage_Loaded(object sender, RoutedEventArgs e) { //Check and see if we have a newer .XAP file on the server Application.Current.CheckAndDownloadUpdateAsync(); Application.Current.CheckAndDownloadUpdateCompleted += (s, e) => { if (e.UpdateAvailable) { MessageBox.Show( "An update has been installed. To see the updates please exit and restart the application"); } }; } Tip/Trick #18) What is it? Prevent development Web Service references from breaking when Visual Studio auto generates a new port number. Why do I care?  We have all been there, we are developing a Silverlight Application and all of a sudden our development web services break. We check and find out that the local port number that Visual Studio assigned has changed and now we need up to update all of our service references. We need a way to stop this. How do I do it: This can actually be prevented with just a few mouse click. Right click on your web solution and goto properties. Click the tab that says, Web. You just need to click the radio button and specify a port number. Now you won’t be bothered with that anymore. Tip/Trick #19) What is it? You can disable the Close Button a ChildWindow. Why do I care?  I wouldn’t blog about it if I hadn’t seen it. Devs trying to override keystrokes to prevent users from closing a Child Window. How do I do it: A property exist on the ChildWindow called “HasCloseButton”, you simply change that to false and your close button is gone. You can delete the “Cancel” button and add some logic to the OK button if you want the user to respond before proceeding. Tip/Trick #20) What is it? Cleanup your XAML. Why do I care?  By removing unneeded namespaces, not naming all of your controls and getting rid of designer markup you can improve code quality and readability. How do I do it: (This is a 3 in one tip) Remove unused Designer markup: 1) Have you ever wondered what the following code snippet does? xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480" This code is telling the designer to do something special with this page in “Design mode” Specifically the width and the height of the page. When its running in the browser it will not use this information and it is actually ignored by the XAML parser. In other words, if you don’t need it then delete it. 2) If you are not using a namespace then remove it. In the code sample below, I am using Resharper which will tell me the ones that I’m not using by the grayed out line below. If you don’t have resharper you can look in your XAML and manually remove the unneeded namespaces. 3) Don’t name an control unless you actually need to refer to it in procedural code. If you name a control you will take a slight performance hit that is totally unnecessary if its not being called. <TextBlock Height="23" Text="TextBlock" />   That is the end of the series. I hope that you enjoyed it and please check out Part 1 | Part 2 | Part 3 if your hungry for more.  Subscribe to my feed CodeProject

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• Plagued by multithreaded bugs

  - by koncurrency

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

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• Help with Boost Grammar

  - by Decmanc04

  I have been using the following win32 console code to try to parse a B Machine Grammar embedded within C++ using Boost Spirit grammar template. I am a relatively new Boost user. The code compiles, but when I run the .exe file produced by VC++2008, the program partially parses the input file. I believe the problem is with my grammar definition or the functions attached as semantic atctions. The code is given below: // BIFAnalyser.cpp : Defines the entry point for the console application. // // /*============================================================================= Copyright (c) Temitope Jos Onunkun 2010 http://www.dcs.kcl.ac.uk/pg/onun/ Use, modification and distribution is subject to the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) =============================================================================*/ //////////////////////////////////////////////////////////////////////////// // // // B Machine parser using the Boost "Grammar" and "Semantic Actions". // // // //////////////////////////////////////////////////////////////////////////// #include <boost/spirit/core.hpp> #include <boost/tokenizer.hpp> #include <iostream> #include <string> #include <fstream> #include <vector> #include <utility> /////////////////////////////////////////////////////////////////////////////////////////// using namespace std; using namespace boost::spirit; /////////////////////////////////////////////////////////////////////////////////////////// // // Semantic actions // //////////////////////////////////////////////////////////////////////////// vector<string> strVect; namespace { //semantic action function on individual lexeme void do_noint(char const* str, char const* end) { string s(str, end); if(atoi(str)) { ; } else { strVect.push_back(s); cout << "PUSH(" << s << ')' << endl; } } //semantic action function on addition of lexemes void do_add(char const*, char const*) { cout << "ADD" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on subtraction of lexemes void do_subt(char const*, char const*) { cout << "SUBTRACT" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on multiplication of lexemes void do_mult(char const*, char const*) { cout << "\nMULTIPLY" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; cout << "\n"; } //semantic action function on division of lexemes void do_div(char const*, char const*) { cout << "\nDIVIDE" << endl; for(vector<string>::iterator vi = strVect.begin(); vi < strVect.end(); ++vi) cout << *vi << " "; } //semantic action function on simple substitution void do_sSubst(char const* str, char const* end) { string s(str, end); //use boost tokenizer to break down tokens typedef boost::tokenizer<boost::char_separator<char> > Tokenizer; boost::char_separator<char> sep("-+/*:=()"); // default char separator Tokenizer tok(s, sep); Tokenizer::iterator tok_iter = tok.begin(); pair<string, string > dependency; //create a pair object for dependencies //save first variable token in simple substitution dependency.first = *tok.begin(); //create a vector object to store all tokens vector<string> dx; // for( ; tok_iter != tok.end(); ++tok_iter) //save all tokens in vector { dx.push_back(*tok_iter ); } vector<string> d_hat; //stores set of dependency pairs string dep; //pairs variables as string object for(int unsigned i=1; i < dx.size()-1; i++) { dependency.second = dx.at(i); dep = dependency.first + "|->" + dependency.second + " "; d_hat.push_back(dep); } cout << "PUSH(" << s << ')' << endl; for(int unsigned i=0; i < d_hat.size(); i++) cout <<"\n...\n" << d_hat.at(i) << " "; cout << "\nSIMPLE SUBSTITUTION\n"; } //semantic action function on multiple substitution void do_mSubst(char const* str, char const* end) { string s(str, end); //use boost tokenizer to break down tokens typedef boost::tokenizer<boost::char_separator<char> > Tok; boost::char_separator<char> sep("-+/*:=()"); // default char separator Tok tok(s, sep); Tok::iterator tok_iter = tok.begin(); // string start = *tok.begin(); vector<string> mx; for( ; tok_iter != tok.end(); ++tok_iter) //save all tokens in vector { mx.push_back(*tok_iter ); } mx.push_back("END\n"); //add a marker "end" for(unsigned int i=0; i<mx.size(); i++) { // if(mx.at(i) == "END" || mx.at(i) == "||" ) // break; // else if( mx.at(i) == "||") // do_sSubst(str, end); // else // { // do_sSubst(str, end); // } cout << "\nTokens ... " << mx.at(i) << " "; } cout << "PUSH(" << s << ')' << endl; cout << "MULTIPLE SUBSTITUTION\n"; } } //////////////////////////////////////////////////////////////////////////// // // Simple Substitution Grammar // //////////////////////////////////////////////////////////////////////////// // Simple substitution grammar parser with integer values removed struct Substitution : public grammar<Substitution> { template <typename ScannerT> struct definition { definition(Substitution const& ) { multi_subst = (simple_subst [&do_mSubst] >> +( str_p("||") >> simple_subst [&do_mSubst]) ) ; simple_subst = (Identifier >> str_p(":=") >> expression)[&do_sSubst] ; Identifier = alpha_p >> +alnum_p//[do_noint] ; expression = term >> *( ('+' >> term)[&do_add] | ('-' >> term)[&do_subt] ) ; term = factor >> *( ('*' >> factor)[&do_mult] | ('/' >> factor)[&do_div] ) ; factor = lexeme_d[( (alpha_p >> +alnum_p) | +digit_p)[&do_noint]] | '(' >> expression >> ')' | ('+' >> factor) ; } rule<ScannerT> expression, term, factor, Identifier, simple_subst, multi_subst ; rule<ScannerT> const& start() const { return multi_subst; } }; }; //////////////////////////////////////////////////////////////////////////// // // Main program // //////////////////////////////////////////////////////////////////////////// int main() { cout << "************************************************************\n\n"; cout << "\t\t...Machine Parser...\n\n"; cout << "************************************************************\n\n"; // cout << "Type an expression...or [q or Q] to quit\n\n"; //prompt for file name to be input cout << "Please enter a filename...or [q or Q] to quit:\n\n "; char strFilename[256]; //file name store as a string object cin >> strFilename; ifstream inFile(strFilename); // opens file object for reading //output file for truncated machine (operations only) Substitution elementary_subst; // Simple substitution parser object string str, next; // inFile.open(strFilename); while (inFile >> str) { getline(cin, next); str += next; if (str.empty() || str[0] == 'q' || str[0] == 'Q') break; parse_info<> info = parse(str.c_str(), elementary_subst, space_p); if (info.full) { cout << "\n-------------------------\n"; cout << "Parsing succeeded\n"; cout << "\n-------------------------\n"; } else { cout << "\n-------------------------\n"; cout << "Parsing failed\n"; cout << "stopped at: \": " << info.stop << "\"\n"; cout << "\n-------------------------\n"; } } cout << "Please enter a filename...or [q or Q] to quit\n"; cin >> strFilename; return 0; } The contents of the file I tried to parse, which I named "mf7.txt" is given below: debt:=(LoanRequest+outstandingLoan1)*20 || newDebt := loanammount-paidammount The output when I execute the program is: ************************************************************ ...Machine Parser... ************************************************************ Please enter a filename...or [q or Q] to quit: c:\tplat\mf7.txt PUSH(LoanRequest) PUSH(outstandingLoan1) ADD LoanRequest outstandingLoan1 MULTIPLY LoanRequest outstandingLoan1 PUSH(debt:=(LoanRequest+outstandingLoan1)*20) ... debt|->LoanRequest ... debt|->outstandingLoan1 SIMPLE SUBSTITUTION Tokens ... debt Tokens ... LoanRequest Tokens ... outstandingLoan1 Tokens ... 20 Tokens ... END PUSH(debt:=(LoanRequest+outstandingLoan1)*20) MULTIPLE SUBSTITUTION ------------------------- Parsing failedstopped at: ": " ------------------------- My intention is to capture only the variables in the file, which I managed to do up to the "||" string. Clearly, the program is not parsing beyond the "||" string in the input file. I will appreciate assistance to fix the grammar. SOS, please.

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