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  • Java JNI leak in c++ process.

    - by user662056
    Hi all.. I am beginner in Java. My problem is: I am calling a Java class's method from c++. For this i am using JNI. Everythings works correct, but i have some memory LEAKS in the process of c++ program... So.. i did simple example.. 1) I create a java machine (jint res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);) 2) then i take a pointer on java class (jclass cls = env-FindClass("test_jni")); 3) after that i create a java class object object, by calling the constructor (testJavaObject = env-NewObject(cls, testConstruct);) AT THIS very moment in the process of c++ program is allocated 10 MB of memory 4) Next i delete the class , the object, and the Java Machine .. AT THIS very moment the 10 MB of memory are not free ................. So below i have a few lines of code c++ program void main() { { //Env JNIEnv *env; // java virtual machine JavaVM *jvm; JavaVMOption* options = new JavaVMOption[1]; //class paths options[0].optionString = "-Djava.class.path=C:/Sun/SDK/jdk/lib;D:/jms_test/java_jni_leak;"; // other options JavaVMInitArgs vm_args; vm_args.version = JNI_VERSION_1_6; vm_args.options = options; vm_args.nOptions = 1; vm_args.ignoreUnrecognized = false; // alloc part of memory (for test) before CreateJavaVM char* testMem0 = new char[1000]; for(int i = 0; i < 1000; ++i) testMem0[i] = 'a'; // create java VM jint res = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args); // alloc part of memory (for test) after CreateJavaVM char* testMem1 = new char[1000]; for(int i = 0; i < 1000; ++i) testMem1[i] = 'b'; //Creating java virtual machine jclass cls = env->FindClass("test_jni"); // Id of a class constructor jmethodID testConstruct = env->GetMethodID(cls, "<init>", "()V"); // The Java Object // Calling the constructor, is allocated 10 MB of memory in c++ process jobject testJavaObject = env->NewObject(cls, testConstruct); // function DeleteLocalRef, // In this very moment memory not free env->DeleteLocalRef(testJavaObject); env->DeleteLocalRef(cls); // 1!!!!!!!!!!!!! res = jvm->DestroyJavaVM(); delete[] testMem0; delete[] testMem1; // In this very moment memory not free. TO /// } int gg = 0; } java class (it just allocs some memory) import java.util.*; public class test_jni { ArrayList<String> testStringList; test_jni() { System.out.println("start constructor"); testStringList = new ArrayList<String>(); for(int i = 0; i < 1000000; ++i) { // ??????? ?????? testStringList.add("TEEEEEEEEEEEEEEEEST"); } } } process memory view, after crating javaVM and java object: testMem0 and testMem1 - test memory, that's allocated by c++. ************** testMem0 ************** JNI_CreateJavaVM ************** testMem1 ************** // create java object jobject testJavaObject = env->NewObject(cls, testConstruct); ************** process memory view, after destroy javaVM and delete ref on java object: testMem0 and testMem1 are deleted to; ************** JNI_CreateJavaVM ************** // create java object jobject testJavaObject = env->NewObject(cls, testConstruct); ************** So testMem0 and testMem1 is deleted, But JavaVM and Java object not.... Sow what i do wrong... and how i can free memory in the c++ process program.

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  • Java: how to avoid circual references when dumping object information with reflection?

    - by Tom
    I've modified an object dumping method to avoid circual references causing a StackOverflow error. This is what I ended up with: //returns all fields of the given object in a string public static String dumpFields(Object o, int callCount, ArrayList excludeList) { //add this object to the exclude list to avoid circual references in the future if (excludeList == null) excludeList = new ArrayList(); excludeList.add(o); callCount++; StringBuffer tabs = new StringBuffer(); for (int k = 0; k < callCount; k++) { tabs.append("\t"); } StringBuffer buffer = new StringBuffer(); Class oClass = o.getClass(); if (oClass.isArray()) { buffer.append("\n"); buffer.append(tabs.toString()); buffer.append("["); for (int i = 0; i < Array.getLength(o); i++) { if (i < 0) buffer.append(","); Object value = Array.get(o, i); if (value != null) { if (excludeList.contains(value)) { buffer.append("circular reference"); } else if (value.getClass().isPrimitive() || value.getClass() == java.lang.Long.class || value.getClass() == java.lang.String.class || value.getClass() == java.lang.Integer.class || value.getClass() == java.lang.Boolean.class) { buffer.append(value); } else { buffer.append(dumpFields(value, callCount, excludeList)); } } } buffer.append(tabs.toString()); buffer.append("]\n"); } else { buffer.append("\n"); buffer.append(tabs.toString()); buffer.append("{\n"); while (oClass != null) { Field[] fields = oClass.getDeclaredFields(); for (int i = 0; i < fields.length; i++) { if (fields[i] == null) continue; buffer.append(tabs.toString()); fields[i].setAccessible(true); buffer.append(fields[i].getName()); buffer.append("="); try { Object value = fields[i].get(o); if (value != null) { if (excludeList.contains(value)) { buffer.append("circular reference"); } else if ((value.getClass().isPrimitive()) || (value.getClass() == java.lang.Long.class) || (value.getClass() == java.lang.String.class) || (value.getClass() == java.lang.Integer.class) || (value.getClass() == java.lang.Boolean.class)) { buffer.append(value); } else { buffer.append(dumpFields(value, callCount, excludeList)); } } } catch (IllegalAccessException e) { System.out.println("IllegalAccessException: " + e.getMessage()); } buffer.append("\n"); } oClass = oClass.getSuperclass(); } buffer.append(tabs.toString()); buffer.append("}\n"); } return buffer.toString(); } The method is initially called like this: System.out.println(dumpFields(obj, 0, null); So, basically I added an excludeList which contains all the previousely checked objects. Now, if an object contains another object and that object links back to the original object, it should not follow that object further down the chain. However, my logic seems to have a flaw as I still get stuck in an infinite loop. Does anyone know why this is happening?

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  • Creating Key Flex Field (KFF) Bean in OAF

    - by Manoj Madhusoodanan
    This blog describes how to create KFF in OAF Page.Here I am going to demonstrate with standard Job KFF. I have created a new structure in Job KFF which I am going to use it in my custom OAF page.Please see the below pic. In the above created structure I have created following segments.You can see the valuesets also. In the custom page I have created an item with following properties. In the Segment List property you can give which segments are going to use in the KFF. The syntax for defining it is  KFF Code|Segment1|Segment2|Segment3|Segment4|Segment N In the table just create a field to hold the code combination.Please click here to see table script. Code combination will goes into JOB_ID field of the table. In the processRequest method of the page controller add following code snippet to attach the KFF structure and CCID column to the KFF bean. Deploy the files belonging to this solution to the server. Following is the output of the above solution. If you click on JobId you can see the KFF window.   Code Combination Id has created in the table.      

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  • Running ASP.NET Webforms and ASP.NET MVC side by side

    - by rajbk
    One of the nice things about ASP.NET MVC and its older brother ASP.NET WebForms is that they are both built on top of the ASP.NET runtime environment. The advantage of this is that, you can still run them side by side even though MVC and WebForms are different frameworks. Another point to note is that with the release of the ASP.NET routing in .NET 3.5 SP1, we are able to create SEO friendly URLs that do not map to specific files on disk. The routing is part of the core runtime environment and therefore can be used by both WebForms and MVC. To run both frameworks side by side, we could easily create a separate folder in your MVC project for all our WebForm files and be good to go. What this post shows you instead, is how to have an MVC application with WebForm pages  that both use a common master page and common routing for SEO friendly URLs.  A sample project that shows WebForms and MVC running side by side is attached at the bottom of this post. So why would we want to run WebForms and MVC in the same project?  WebForms come with a lot of nice server controls that provide a lot of functionality. One example is the ReportViewer control. Using this control and client report definition files (RDLC), we can create rich interactive reports (with charting controls). I show you how to use the ReportViewer control in a WebForm project here :  Creating an ASP.NET report using Visual Studio 2010. We can create even more advanced reports by using SQL reporting services that can also be rendered by the ReportViewer control. Now, consider the sample MVC application I blogged about called ASP.NET MVC Paging/Sorting/Filtering using the MVCContrib Grid and Pager. Assume you were given the requirement to add a UI to the MVC application where users could interact with a report and be given the option to export the report to Excel, PDF or Word. How do you go about doing it?   This is a perfect scenario to use the ReportViewer control and RDLCs. As you saw in the post on creating the ASP.NET report, the ReportViewer control is a Web Control and is designed to be run in a WebForm project with dependencies on, amongst others, a ScriptManager control and the beloved Viewstate.  Since MVC and WebForm both run under the same runtime, the easiest thing to is to add the WebForm application files (index.aspx, rdlc, related class files) into our MVC project. You can copy the files over from the WebForm project into the MVC project. Create a new folder in our MVC application called CommonReports. Add the index.aspx and rdlc file from the Webform project   Right click on the Index.aspx file and convert it to a web application. This will add the index.aspx.designer.cs file (this step is not required if you are manually adding a WebForm aspx file into the MVC project).    Verify that all the type names for the ObjectDataSources in code behind to point to the correct ProductRepository and fix any compiler errors. Right click on Index.aspx and select “View in browser”. You should see a screen like the one below:   There are two issues with our page. It does not use our site master page and the URL is not SEO friendly. Common Master Page The easiest way to use master pages with both MVC and WebForm pages is to have a common master page that each inherits from as shown below. The reason for this is most WebForm controls require them to be inside a Form control and require ControlState or ViewState. ViewMasterPages used in MVC, on the other hand, are designed to be used with content pages that derive from ViewPage with Viewstate turned off. By having a separate master page for MVC and WebForm that inherit from the Root master page,, we can set properties that are specific to each. For example, in the Webform master, we can turn on ViewState, add a form tag etc. Another point worth noting is that if you set a WebForm page to use a MVC site master page, you may run into errors like the following: A ViewMasterPage can be used only with content pages that derive from ViewPage or ViewPage<TViewItem> or Control 'MainContent_MyButton' of type 'Button' must be placed inside a form tag with runat=server. Since the ViewMasterPage inherits from MasterPage as seen below, we make our Root.master inherit from MasterPage, MVC.master inherit from ViewMasterPage and Webform.master inherits from MasterPage. We define the attributes on the master pages like so: Root.master <%@ Master Inherits="System.Web.UI.MasterPage"  … %> MVC.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="System.Web.Mvc.ViewMasterPage" … %> WebForm.master <%@ Master MasterPageFile="~/Views/Shared/Root.Master" Inherits="NorthwindSales.Views.Shared.Webform" %> Code behind: public partial class Webform : System.Web.UI.MasterPage {} We make changes to our reports aspx file to use the Webform.master. See the source of the master pages in the sample project for a better understanding of how they are connected. SEO friendly links We want to create SEO friendly links that point to our report. A request to /Reports/Products should render the report located in ~/CommonReports/Products.aspx. Simillarly to support future reports, a request to /Reports/Sales should render a report in ~/CommonReports/Sales.aspx. Lets start by renaming our index.aspx file to Products.aspx to be consistent with our routing criteria above. As mentioned earlier, since routing is part of the core runtime environment, we ca easily create a custom route for our reports by adding an entry in Global.asax. public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}");   //Custom route for reports routes.MapPageRoute( "ReportRoute", // Route name "Reports/{reportname}", // URL "~/CommonReports/{reportname}.aspx" // File );     routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } With our custom route in place, a request to Reports/Employees will render the page at ~/CommonReports/Employees.aspx. We make this custom route the first entry since the routing system walks the table from top to bottom, and the first route to match wins. Note that it is highly recommended that you write unit tests for your routes to ensure that the mappings you defined are correct. Common Menu Structure The master page in our original MVC project had a menu structure like so: <ul id="menu"> <li> <%=Html.ActionLink("Home", "Index", "Home") %></li> <li> <%=Html.ActionLink("Products", "Index", "Products") %></li> <li> <%=Html.ActionLink("Help", "Help", "Home") %></li> </ul> We want this menu structure to be common to all pages/views and hence should reside in Root.master. Unfortunately the Html.ActionLink helpers will not work since Root.master inherits from MasterPage which does not have the helper methods available. The quickest way to resolve this issue is to use RouteUrl expressions. Using  RouteUrl expressions, we can programmatically generate URLs that are based on route definitions. By specifying parameter values and a route name if required, we get back a URL string that corresponds to a matching route. We move our menu structure to Root.master and change it to use RouteUrl expressions: <ul id="menu"> <li> <asp:HyperLink ID="hypHome" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=index%>">Home</asp:HyperLink></li> <li> <asp:HyperLink ID="hypProducts" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=products,action=index%>">Products</asp:HyperLink></li> <li> <asp:HyperLink ID="hypReport" runat="server" NavigateUrl="<%$RouteUrl:routename=ReportRoute,reportname=products%>">Product Report</asp:HyperLink></li> <li> <asp:HyperLink ID="hypHelp" runat="server" NavigateUrl="<%$RouteUrl:routename=default,controller=home,action=help%>">Help</asp:HyperLink></li> </ul> We are done adding the common navigation to our application. The application now uses a common theme, routing and navigation structure. Conclusion We have seen how to do the following through this post Add a WebForm page from a WebForm project to an existing ASP.NET MVC application Use a common master page for both WebForm and MVC pages Use routing for SEO friendly links Use a common menu structure for both WebForm and MVC. The sample project is attached below. Version: VS 2010 RTM Remember to change your connection string to point to your Northwind database NorthwindSalesMVCWebform.zip

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  • Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

    - by Reed
    In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations.  Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects.  By introducing Parallelism to our declarative model, we add some extra complexity.  This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable.  The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>.  Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface.  This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Other LINQ variants work in a similar fashion.  For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable.  When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel().  This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ.  There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>.  Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type.  This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>.  The difference only arises at the beginning of our parallelization.  When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel().  There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>.  This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning.  This can be useful if you have an operation which will not parallelize well or is not thread safe.  For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects.  If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation.  PLINQ, by default, does not preserve the order of of source collection. This is by design.  In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time.  Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary.  Therefore, by default, the system is allowed to completely change the order of your sequence during processing.  If you are doing a standard query operation, this is usually not an issue.  However, there are times when keeping a specific ordering in place is important.  If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method.  This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements.  In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved.  To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially.  This will cause our query to run slower, since there is overhead involved in maintaining the ordering.  However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful.  It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously.  There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything.  When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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  • Anti-Forgery Request Recipes For ASP.NET MVC And AJAX

    - by Dixin
    Background To secure websites from cross-site request forgery (CSRF, or XSRF) attack, ASP.NET MVC provides an excellent mechanism: The server prints tokens to cookie and inside the form; When the form is submitted to server, token in cookie and token inside the form are sent in the HTTP request; Server validates the tokens. To print tokens to browser, just invoke HtmlHelper.AntiForgeryToken():<% using (Html.BeginForm()) { %> <%: this.Html.AntiForgeryToken(Constants.AntiForgeryTokenSalt)%> <%-- Other fields. --%> <input type="submit" value="Submit" /> <% } %> This invocation generates a token then writes inside the form:<form action="..." method="post"> <input name="__RequestVerificationToken" type="hidden" value="J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP" /> <!-- Other fields. --> <input type="submit" value="Submit" /> </form> and also writes into the cookie: __RequestVerificationToken_Lw__= J56khgCvbE3bVcsCSZkNVuH9Cclm9SSIT/ywruFsXEgmV8CL2eW5C/gGsQUf/YuP When the above form is submitted, they are both sent to server. In the server side, [ValidateAntiForgeryToken] attribute is used to specify the controllers or actions to validate them:[HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult Action(/* ... */) { // ... } This is very productive for form scenarios. But recently, when resolving security vulnerabilities for Web products, some problems are encountered. Specify validation on controller (not on each action) The server side problem is, It is expected to declare [ValidateAntiForgeryToken] on controller, but actually it has be to declared on each POST actions. Because POST actions are usually much more then controllers, the work would be a little crazy. Problem Usually a controller contains actions for HTTP GET and actions for HTTP POST requests, and usually validations are expected for HTTP POST requests. So, if the [ValidateAntiForgeryToken] is declared on the controller, the HTTP GET requests become invalid:[ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public class SomeController : Controller // One [ValidateAntiForgeryToken] attribute. { [HttpGet] public ActionResult Index() // Index() cannot work. { // ... } [HttpPost] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] public ActionResult PostAction2(/* ... */) { // ... } // ... } If browser sends an HTTP GET request by clicking a link: http://Site/Some/Index, validation definitely fails, because no token is provided. So the result is, [ValidateAntiForgeryToken] attribute must be distributed to each POST action:public class SomeController : Controller // Many [ValidateAntiForgeryToken] attributes. { [HttpGet] public ActionResult Index() // Works. { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction1(/* ... */) { // ... } [HttpPost] [ValidateAntiForgeryToken(Salt = Constants.AntiForgeryTokenSalt)] public ActionResult PostAction2(/* ... */) { // ... } // ... } This is a little bit crazy, because one application can have a lot of POST actions. Solution To avoid a large number of [ValidateAntiForgeryToken] attributes (one for each POST action), the following ValidateAntiForgeryTokenWrapperAttribute wrapper class can be helpful, where HTTP verbs can be specified:[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = true)] public class ValidateAntiForgeryTokenWrapperAttribute : FilterAttribute, IAuthorizationFilter { private readonly ValidateAntiForgeryTokenAttribute _validator; private readonly AcceptVerbsAttribute _verbs; public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs) : this(verbs, null) { } public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs, string salt) { this._verbs = new AcceptVerbsAttribute(verbs); this._validator = new ValidateAntiForgeryTokenAttribute() { Salt = salt }; } public void OnAuthorization(AuthorizationContext filterContext) { string httpMethodOverride = filterContext.HttpContext.Request.GetHttpMethodOverride(); if (this._verbs.Verbs.Contains(httpMethodOverride, StringComparer.OrdinalIgnoreCase)) { this._validator.OnAuthorization(filterContext); } } } When this attribute is declared on controller, only HTTP requests with the specified verbs are validated:[ValidateAntiForgeryTokenWrapper(HttpVerbs.Post, Constants.AntiForgeryTokenSalt)] public class SomeController : Controller { // GET actions are not affected. // Only HTTP POST requests are validated. } Now one single attribute on controller turns on validation for all POST actions. Maybe it would be nice if HTTP verbs can be specified on the built-in [ValidateAntiForgeryToken] attribute, which is easy to implemented. Specify Non-constant salt in runtime By default, the salt should be a compile time constant, so it can be used for the [ValidateAntiForgeryToken] or [ValidateAntiForgeryTokenWrapper] attribute. Problem One Web product might be sold to many clients. If a constant salt is evaluated in compile time, after the product is built and deployed to many clients, they all have the same salt. Of course, clients do not like this. Even some clients might want to specify a custom salt in configuration. In these scenarios, salt is required to be a runtime value. Solution In the above [ValidateAntiForgeryToken] and [ValidateAntiForgeryTokenWrapper] attribute, the salt is passed through constructor. So one solution is to remove this parameter:public class ValidateAntiForgeryTokenWrapperAttribute : FilterAttribute, IAuthorizationFilter { public ValidateAntiForgeryTokenWrapperAttribute(HttpVerbs verbs) { this._verbs = new AcceptVerbsAttribute(verbs); this._validator = new ValidateAntiForgeryTokenAttribute() { Salt = AntiForgeryToken.Value }; } // Other members. } But here the injected dependency becomes a hard dependency. So the other solution is moving validation code into controller to work around the limitation of attributes:public abstract class AntiForgeryControllerBase : Controller { private readonly ValidateAntiForgeryTokenAttribute _validator; private readonly AcceptVerbsAttribute _verbs; protected AntiForgeryControllerBase(HttpVerbs verbs, string salt) { this._verbs = new AcceptVerbsAttribute(verbs); this._validator = new ValidateAntiForgeryTokenAttribute() { Salt = salt }; } protected override void OnAuthorization(AuthorizationContext filterContext) { base.OnAuthorization(filterContext); string httpMethodOverride = filterContext.HttpContext.Request.GetHttpMethodOverride(); if (this._verbs.Verbs.Contains(httpMethodOverride, StringComparer.OrdinalIgnoreCase)) { this._validator.OnAuthorization(filterContext); } } } Then make controller classes inheriting from this AntiForgeryControllerBase class. Now the salt is no long required to be a compile time constant. Submit token via AJAX For browser side, once server side turns on anti-forgery validation for HTTP POST, all AJAX POST requests will fail by default. Problem In AJAX scenarios, the HTTP POST request is not sent by form. Take jQuery as an example:$.post(url, { productName: "Tofu", categoryId: 1 // Token is not posted. }, callback); This kind of AJAX POST requests will always be invalid, because server side code cannot see the token in the posted data. Solution Basically, the tokens must be printed to browser then sent back to server. So first of all, HtmlHelper.AntiForgeryToken() need to be called somewhere. Now the browser has token in both HTML and cookie. Then jQuery must find the printed token in the HTML, and append token to the data before sending:$.post(url, { productName: "Tofu", categoryId: 1, __RequestVerificationToken: getToken() // Token is posted. }, callback); To be reusable, this can be encapsulated into a tiny jQuery plugin:/// <reference path="jquery-1.4.2.js" /> (function ($) { $.getAntiForgeryToken = function (tokenWindow, appPath) { // HtmlHelper.AntiForgeryToken() must be invoked to print the token. tokenWindow = tokenWindow && typeof tokenWindow === typeof window ? tokenWindow : window; appPath = appPath && typeof appPath === "string" ? "_" + appPath.toString() : ""; // The name attribute is either __RequestVerificationToken, // or __RequestVerificationToken_{appPath}. tokenName = "__RequestVerificationToken" + appPath; // Finds the <input type="hidden" name={tokenName} value="..." /> from the specified. // var inputElements = $("input[type='hidden'][name='__RequestVerificationToken" + appPath + "']"); var inputElements = tokenWindow.document.getElementsByTagName("input"); for (var i = 0; i < inputElements.length; i++) { var inputElement = inputElements[i]; if (inputElement.type === "hidden" && inputElement.name === tokenName) { return { name: tokenName, value: inputElement.value }; } } return null; }; $.appendAntiForgeryToken = function (data, token) { // Converts data if not already a string. if (data && typeof data !== "string") { data = $.param(data); } // Gets token from current window by default. token = token ? token : $.getAntiForgeryToken(); // $.getAntiForgeryToken(window). data = data ? data + "&" : ""; // If token exists, appends {token.name}={token.value} to data. return token ? data + encodeURIComponent(token.name) + "=" + encodeURIComponent(token.value) : data; }; // Wraps $.post(url, data, callback, type). $.postAntiForgery = function (url, data, callback, type) { return $.post(url, $.appendAntiForgeryToken(data), callback, type); }; // Wraps $.ajax(settings). $.ajaxAntiForgery = function (settings) { settings.data = $.appendAntiForgeryToken(settings.data); return $.ajax(settings); }; })(jQuery); In most of the scenarios, it is Ok to just replace $.post() invocation with $.postAntiForgery(), and replace $.ajax() with $.ajaxAntiForgery():$.postAntiForgery(url, { productName: "Tofu", categoryId: 1 }, callback); // Token is posted. There might be some scenarios of custom token, where $.appendAntiForgeryToken() is useful:data = $.appendAntiForgeryToken(data, token); // Token is already in data. No need to invoke $.postAntiForgery(). $.post(url, data, callback); And there are scenarios that the token is not in the current window. For example, an HTTP POST request can be sent by an iframe, while the token is in the parent window. Here, token's container window can be specified for $.getAntiForgeryToken():data = $.appendAntiForgeryToken(data, $.getAntiForgeryToken(window.parent)); // Token is already in data. No need to invoke $.postAntiForgery(). $.post(url, data, callback); If you have better solution, please do tell me.

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  • MySQL – Beginning Temporary Tables in MySQL

    - by Pinal Dave
    MySQL supports Temporary tables to store the resultsets temporarily for a given connection. Temporary tables are created with the keyword TEMPORARY along with the CREATE TABLE statement. Let us create the temporary table named Temp CREATE TEMPORARY TABLE TEMP (id INT); Now you can find out the column names using DESC command DESC TEMP; The above returns the following result This table can be accessed only for the current connection and it can be used like a permanent table and automatically dropped when the connection is closed. However, you can not find temporary tables using INFORMATION_SCHEMA. TABLES system view. It will only list out the permanent tables. MySQL usually stores the data of temporary tables in memory and processed by Memory Storage engine. But if the data size is too large MySQL automatically converts this to the on – disk table and use MyISAM engine. You can also create a permanent table with the same name of a temporary table in the same connection. However the structure of permanent table is visible only if the temporary table with the same name is dropped. Let us create a permanent table with the same name Temp as below CREATE TABLE TEMP (id INT, names VARCHAR(100)); Now running the following command stills gives you the structure of the temporary table temp created earlier. DESC TEMP; You can drop the temporary table using DROP TEMPORARY TABLE command; DROP TEMPORARY TABLE TEMP; After you executed the temporary table, run the following command DESC TEMP; Now you will see the structure of the permanent table named temp In summary – If there is a Temporary Table in MySQL it gets first priority over the permanent table in the session. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Tips and Tricks, T SQL

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  • Adding objects to the environment at timed intervals

    - by david
    I am using an ArrayList to handle objects and at each interval of 120 frames, I am adding a new object of the same type at a random location along the z-axis of 60. The problem is, it doesn't add just 1. It depends on how many are in the list. If I kill the Fox before the time interval when one is supposed to spawn comes, then no Fox will be spawned. If I don't kill any foxes, it grows exponentially. I only want one Fox to be added every 120 frames. This problem never happened before when I created new ones and added them to the environment. Any insights? Here is my code: /**** FOX CLASS ****/ import env3d.EnvObject; import java.util.ArrayList; public class Fox extends Creature { private int frame = 0; public Fox(double x, double y, double z) { super(x, y, z); // Must use the mutator as the fields have private access // in the parent class setTexture("models/fox/fox.png"); setModel("models/fox/fox.obj"); setScale(1.4); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; setX(getX()-0.2); setRotateY(270); if (frame > 120) { Fox f = new Fox(60, 1, (int)(Math.random()*28)+1); new_creatures.add(f); frame = 0; } for (Creature c : creatures) { if (this.distance(c) < this.getScale()+c.getScale() && c instanceof Tux) { dead_creatures.add(c); } } for (Creature c : creatures) { if (c.getX() < 1 && c instanceof Fox) { dead_creatures.add(c); } } } } import env3d.Env; import java.util.ArrayList; import org.lwjgl.input.Keyboard; /** * A predator and prey simulation. Fox is the predator and Tux is the prey. */ public class Game { private Env env; private boolean finished; private ArrayList<Creature> creatures; private KingTux king; private Snowball ball; private int tuxcounter; private int kills; /** * Constructor for the Game class. It sets up the foxes and tuxes. */ public Game() { // we use a separate ArrayList to keep track of each animal. // our room is 50 x 50. creatures = new ArrayList<Creature>(); for (int i = 0; i < 10; i++) { creatures.add(new Tux((int)(Math.random()*10)+1, 1, (int)(Math.random()*28)+1)); } for (int i = 0; i < 1; i++) { creatures.add(new Fox(60, 1, (int)(Math.random()*28)+1)); } king = new KingTux(25, 1, 35); ball = new Snowball(-400, -400, -400); } /** * Play the game */ public void play() { finished = false; // Create the new environment. Must be done in the same // method as the game loop env = new Env(); // Make the room 50 x 50. env.setRoom(new Room()); // Add all the animals into to the environment for display for (Creature c : creatures) { env.addObject(c); } for (Creature c : creatures) { if (c instanceof Tux) { tuxcounter++; } } env.addObject(king); env.addObject(ball); // Sets up the camera env.setCameraXYZ(30, 50, 55); env.setCameraPitch(-63); // Turn off the default controls env.setDefaultControl(false); // A list to keep track of dead tuxes. ArrayList<Creature> dead_creatures = new ArrayList<Creature>(); ArrayList<Creature> new_creatures = new ArrayList<Creature>(); // The main game loop while (!finished) { if (env.getKey() == 1 || tuxcounter == 0) { finished = true; } env.setDisplayStr("Tuxes: " + tuxcounter, 15, 0); env.setDisplayStr("Kills: " + kills, 140, 0); processInput(); ball.move(); king.check(); // Move each fox and tux. for (Creature c : creatures) { c.move(creatures, dead_creatures, new_creatures); } for (Creature c : creatures) { if (c.distance(ball) < c.getScale()+ball.getScale() && c instanceof Fox) { dead_creatures.add(c); ball.setX(-400); ball.setY(-400); ball.setZ(-400); kills++; } } // Clean up of the dead tuxes. for (Creature c : dead_creatures) { if (c instanceof Tux) { tuxcounter--; } env.removeObject(c); creatures.remove(c); } for (Creature c : new_creatures) { creatures.add(c); env.addObject(c); } // we clear the ArrayList for the next loop. We could create a new one // every loop but that would be very inefficient. dead_creatures.clear(); new_creatures.clear(); // Update display env.advanceOneFrame(); } // Just a little clean up env.exit(); } private void processInput() { int keyDown = env.getKeyDown(); int key = env.getKey(); if (keyDown == 203) { king.setX(king.getX()-1); } else if (keyDown == 205) { king.setX(king.getX()+1); } if (ball.getX() <= -400 && key == Keyboard.KEY_S) { ball.setX(king.getX()); ball.setY(king.getY()); ball.setZ(king.getZ()); } } /** * Main method to launch the program. */ public static void main(String args[]) { (new Game()).play(); } } /**** CREATURE CLASS ****/ /* (Parent class to Tux, Fox, and KingTux) */ import env3d.EnvObject; import java.util.ArrayList; abstract public class Creature extends EnvObject { private int frame; private double rand; /** * Constructor for objects of class Creature */ public Creature(double x, double y, double z) { setX(x); setY(y); setZ(z); setScale(1); rand = Math.random(); } private void randomGenerator() { rand = Math.random(); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; if (frame > 12) { randomGenerator(); frame = 0; } // if (rand < 0.25) { // setX(getX()+0.3); // setRotateY(90); // } else if (rand < 0.5) { // setX(getX()-0.3); // setRotateY(270); // } else if (rand < 0.75) { // setZ(getZ()+0.3); // setRotateY(0); // } else if (rand < 1) { // setZ(getZ()-0.3); // setRotateY(180); // } if (rand < 0.5) { setRotateY(getRotateY()-7); } else if (rand < 1) { setRotateY(getRotateY()+7); } setX(getX()+Math.sin(Math.toRadians(getRotateY()))*0.5); setZ(getZ()+Math.cos(Math.toRadians(getRotateY()))*0.5); if (getX() < getScale()) setX(getScale()); if (getX() > 50-getScale()) setX(50 - getScale()); if (getZ() < getScale()) setZ(getScale()); if (getZ() > 50-getScale()) setZ(50 - getScale()); // The move method now handles collision detection if (this instanceof Fox) { for (Creature c : creatures) { if (c.distance(this) < c.getScale()+this.getScale() && c instanceof Tux) { dead_creatures.add(c); } } } } } The rest of the classes are a bit trivial to this specific problem.

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  • Structuring database for multi-object "activity" and "following" functionalities

    - by romaninsh
    I am working on a web application which operate with different types of objects such as user, profiles, pages etc. All objects have unique object_id. When objects interact it may produce "activity", such as user posting on the page or profile. Activity may be related to multiple objects through their object_id. Users may also follow "objects" and they need to be able to see stream of relevant activity. Could you provide me with some data structure suggestions which would be efficient and scalable? My goal is to show activity limited to the objects which user is following I am not limited by relational databases. Update As I'm getting advices on ORM and how index things, I'd like to again, stress my question. According to my current design model the database structure looks like this: As you can see - it's quite easy to implement database like that. Activity and Follower tables do contain much larger amount of records than the upper level but it's tolerable. But when it comes for me to create a "timeline" table, it becomes a nightmare. For every user I need to reference all the object activities which he follows. In terms of records it easily gets out of control. Please suggest me how to change this structure to avoid timeline creation and also be abel to quickly retrieve activity for any given user. Thanks.

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  • The UIManager Pattern

    - by Duncan Mills
    One of the most common mistakes that I see when reviewing ADF application code, is the sin of storing UI component references, most commonly things like table or tree components in Session or PageFlow scope. The reasons why this is bad are simple; firstly, these UI object references are not serializable so would not survive a session migration between servers and secondly there is no guarantee that the framework will re-use the same component tree from request to request, although in practice it generally does do so. So there danger here is, that at best you end up with an NPE after you session has migrated, and at worse, you end up pinning old generations of the component tree happily eating up your precious memory. So that's clear, we should never. ever, be storing references to components anywhere other than request scope (or maybe backing bean scope). So double check the scope of those binding attributes that map component references into a managed bean in your applications.  Why is it Such a Common Mistake?  At this point I want to examine why there is this urge to hold onto these references anyway? After all, JSF will obligingly populate your backing beans with the fresh and correct reference when needed.   In most cases, it seems that the rational is down to a lack of distinction within the application between what is data and what is presentation. I think perhaps, a cause of this is the logical separation between business data behind the ADF data binding (#{bindings}) façade and the UI components themselves. Developers tend to think, OK this is my data layer behind the bindings object and everything else is just UI.  Of course that's not the case.  The UI layer itself will have state which is intrinsically linked to the UI presentation rather than the business model, but at the same time should not be tighly bound to a specific instance of any single UI component. So here's the problem.  I think developers try and use the UI components as state-holders for this kind of data, rather than using them to represent that state. An example of this might be something like the selection state of a tabset (panelTabbed), you might be interested in knowing what the currently disclosed tab is. The temptation that leads to the component reference sin is to go and ask the tabset what the selection is.  That of course is fine in context - e.g. a handler within the same request scoped bean that's got the binding to the tabset. However, it leads to problems when you subsequently want the same information outside of the immediate scope.  The simple solution seems to be to chuck that component reference into session scope and then you can simply re-check in the same way, leading of course to this mistake. Turn it on its Head  So the correct solution to this is to turn the problem on its head. If you are going to be interested in the value or state of some component outside of the immediate request context then it becomes persistent state (persistent in the sense that it extends beyond the lifespan of a single request). So you need to externalize that state outside of the component and have the component reference and manipulate that state as needed rather than owning it. This is what I call the UIManager pattern.  Defining the Pattern The  UIManager pattern really is very simple. The premise is that every application should define a session scoped managed bean, appropriately named UIManger, which is specifically responsible for holding this persistent UI component related state.  The actual makeup of the UIManger class varies depending on a needs of the application and the amount of state that needs to be stored. Generally I'll start off with a Map in which individual flags can be created as required, although you could opt for a more formal set of typed member variables with getters and setters, or indeed a mix. This UIManager class is defined as a session scoped managed bean (#{uiManager}) in the faces-config.xml.  The pattern is to then inject this instance of the class into any other managed bean (usually request scope) that needs it using a managed property.  So typically you'll have something like this:   <managed-bean>     <managed-bean-name>uiManager</managed-bean-name>     <managed-bean-class>oracle.demo.view.state.UIManager</managed-bean-class>     <managed-bean-scope>session</managed-bean-scope>   </managed-bean>  When is then injected into any backing bean that needs it:    <managed-bean>     <managed-bean-name>mainPageBB</managed-bean-name>     <managed-bean-class>oracle.demo.view.MainBacking</managed-bean-class>     <managed-bean-scope>request</managed-bean-scope>     <managed-property>       <property-name>uiManager</property-name>       <property-class>oracle.demo.view.state.UIManager</property-class>       <value>#{uiManager}</value>     </managed-property>   </managed-bean> In this case the backing bean in question needs a member variable to hold and reference the UIManager: private UIManager _uiManager;  Which should be exposed via a getter and setter pair with names that match the managed property name (e.g. setUiManager(UIManager _uiManager), getUiManager()).  This will then give your code within the backing bean full access to the UI state. UI components in the page can, of course, directly reference the uiManager bean in their properties, for example, going back to the tab-set example you might have something like this: <af:paneltabbed>   <af:showDetailItem text="First"                disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['FIRST']}"> ...   </af:showDetailItem>   <af:showDetailItem text="Second"                      disclosed="#{uiManager.settings['MAIN_TABSET_STATE'].['SECOND']}">     ...   </af:showDetailItem>   ... </af:panelTabbed> Where in this case the settings member within the UI Manger is a Map which contains a Map of Booleans for each tab under the MAIN_TABSET_STATE key. (Just an example you could choose to store just an identifier for the selected tab or whatever, how you choose to store the state within UI Manger is up to you.) Get into the Habit So we can see that the UIManager pattern is not great strain to implement for an application and can even be retrofitted to an existing application with ease. The point is, however, that you should always take this approach rather than committing the sin of persistent component references which will bite you in the future or shotgun scattered UI flags on the session which are hard to maintain.  If you take the approach of always accessing all UI state via the uiManager, or perhaps a pageScope focused variant of it, you'll find your applications much easier to understand and maintain. Do it today!

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  • Dynamically changing DVT Graph at Runtime

    - by mona.rakibe(at)oracle.com
    I recently came across this requirement where the customer wanted to change the graph type at run-time based on some selection. After some internal discussions we realized this can be best achieved by using af:switcher to toggle between multiple graphs. In this blog I will be sharing the sample that I build to demonstrate this.[Note] : In the below sample, every-time user changes graph type there is a server trip, so please use this approach with performance implications in mind.This sample can be downloaded  from DynamicGraph.zipSet-up: Create a BAM data control using employees DO (sample)(Refer this entry)Steps:Create the View Create a new JSF page .From component palette drag and drop "Select One Radio" into this page Enter some Label and click "Finish"In Property Editor set the "AutoSubmit" property to trueNow drag and drop "Switcher" from components into this page.In the Structure pane select the af:switcher right click and surround with "PanelGroupLayout"In Property Editor set the "PartialTriggers"  property of PanelGroupLayout to the id of af:selectOneRadioAgain in the Structure pane select the af:switcher right click and select "Insert inside af:switcher->facet"Enter Facet name (ex: pie)Again in the Structure pane select the af:switcher right click and select "Insert inside af:switcher->facet" Enter  another Facet name (ex: bar)From "Data Controls" drag and drop "Employees->Query"  into the pie facet as "Graph->Pie" (Pie: Sales_Number and Slices: Salesperson)From "Data Controls" drag and drop "Employees->Query"  into the bar facet as "Graph->Bar" (Bars :Sales_Number and X-axis : Salesperson).Now wire the switcher to the af:selectOneRadio using their "facetName" and "value" property respectively.Now run the page, notice that graph renders as per the selection by user.

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  • Boost your infrastructure with Coherence into the Cloud

    - by Nino Guarnacci
    Authors: Nino Guarnacci & Francesco Scarano,  at this URL could be found the original article:  http://blogs.oracle.com/slc/coherence_into_the_cloud_boost. Thinking about the enterprise cloud, come to mind many possible configurations and new opportunities in enterprise environments. Various customers needs that serve as guides to this new trend are often very different, but almost always united by two main objectives: Elasticity of infrastructure both Hardware and Software Investments related to the progressive needs of the current infrastructure Characteristics of innovation and economy. A concrete use case that I worked on recently demanded the fulfillment of two basic requirements of economy and innovation.The client had the need to manage a variety of data cache, which can process complex queries and parallel computational operations, maintaining the caches in a consistent state on different server instances, on which the application was installed.In addition, the customer was looking for a solution that would allow him to manage the likely situations in load peak during certain times of the year.For this reason, the customer requires a replication site, on which convey part of the requests during periods of peak; the desire was, however, to prevent the immobilization of investments in owned hardware-software architectures; so, to respond to this need, it was requested to seek a solution based on Cloud technologies and architectures already offered by the market. Coherence can already now address the requirements of large cache between different nodes in the cluster, providing further technology to search and parallel computing, with the simultaneous use of all hardware infrastructure resources. Moreover, thanks to the functionality of "Push Replication", which can replicate and update the information contained in the cache, even to a site hosted in the cloud, it is satisfied the need to make resilient infrastructure that can be based also on nodes temporarily housed in the Cloud architectures. There are different types of configurations that can be realized using the functionality "Push-Replication" of Coherence. Configurations can be either: Active - Passive  Hub and Spoke Active - Active Multi Master Centralized Replication Whereas the architecture of this particular project consists of two sites (Site 1 and Site Cloud), between which only Site 1 is enabled to write into the cache, it was decided to adopt an Active-Passive Configuration type (Hub and Spoke). If, however, the requirement should change over time, it will be particularly easy to change this configuration in an Active-Active configuration type. Although very simple, the small sample in this post, inspired by the specific project is effective, to better understand the features and capabilities of Coherence and its configurations. Let's create two distinct coherence cluster, located at miles apart, on two different domain contexts, one of them "hosted" at home (on-premise) and the other one hosted by any cloud provider on the network (or just the same laptop to test it :)). These two clusters, which we call Site 1 and Site Cloud, will contain the necessary information, so a simple client can insert data only into the Site 1. On both sites will be subscribed a listener, who listens to the variations of specific objects within the various caches. To implement these features, you need 4 simple classes: CachedResponse.java Represents the POJO class that will be inserted into the cache, and fulfills the task of containing useful information about the hypothetical links navigation ResponseSimulatorHelper.java Represents a link simulator, which has the task of randomly creating objects of type CachedResponse that will be added into the caches CacheCommands.java Represents the model of our example, because it is responsible for receiving instructions from the controller and performing basic operations against the cache, such as insert, delete, update, listening, objects within the cache Shell.java It is our controller, which give commands to be executed within the cache of the two Sites So, summarily, we execute the java class "Shell", asking it to put into the cache 100 objects of type "CachedResponse" through the java class "CacheCommands", then the simulator "ResponseSimulatorHelper" will randomly create new instances of objects "CachedResponse ". Finally, the Shell class will listen to for events occurring within the cache on the Site Cloud, while insertions and deletions are performed on Site 1. Now, we realize the two configurations of two respective sites / cluster: Site 1 and Site Cloud.For the Site 1 we define a cache of type "distributed" with features of "read and write", using the cache class store for the "push replication", a functionality offered by the project "incubator" of Oracle Coherence.For the "Site Cloud" we expect even the definition of “distributed” cache type with tcp proxy feature enabled, so it can receive updates from Site 1.  Coherence Cache Config XML file for "storage node" on "Site 1" site1-prod-cache-config.xml Coherence Cache Config XML file for "storage node" on "Site Cloud" site2-prod-cache-config.xml For two clients "Shell" which will connect respectively to the two clusters we have provided two easy access configurations.  Coherence Cache Config XML file for Shell on "Site 1" site1-shell-prod-cache-config.xml Coherence Cache Config XML file for Shell on "Site Cloud" site2-shell-prod-cache-config.xml Now, we just have to get everything and run our tests. To start at least one "storage" node (which holds the data) for the "Cloud Site", we can run the standard class  provided OOTB by Oracle Coherence com.tangosol.net.DefaultCacheServer with the following parameters and values:-Xmx128m-Xms64m-Dcom.sun.management.jmxremote -Dtangosol.coherence.management=all -Dtangosol.coherence.management.remote=true -Dtangosol.coherence.distributed.localstorage=true -Dtangosol.coherence.cacheconfig=config/site2-prod-cache-config.xml-Dtangosol.coherence.clusterport=9002-Dtangosol.coherence.site=SiteCloud To start at least one "storage" node (which holds the data) for the "Site 1", we can perform again the standard class provided by Coherence  com.tangosol.net.DefaultCacheServer with the following parameters and values:-Xmx128m-Xms64m-Dcom.sun.management.jmxremote -Dtangosol.coherence.management=all -Dtangosol.coherence.management.remote=true -Dtangosol.coherence.distributed.localstorage=true -Dtangosol.coherence.cacheconfig=config/site1-prod-cache-config.xml-Dtangosol.coherence.clusterport=9001-Dtangosol.coherence.site=Site1 Then, we start the first client "Shell" for the "Cloud Site", launching the java class it.javac.Shell  using these parameters and values: -Xmx64m-Xms64m-Dcom.sun.management.jmxremote -Dtangosol.coherence.management=all -Dtangosol.coherence.management.remote=true -Dtangosol.coherence.distributed.localstorage=false -Dtangosol.coherence.cacheconfig=config/site2-shell-prod-cache-config.xml-Dtangosol.coherence.clusterport=9002-Dtangosol.coherence.site=SiteCloud Finally, we start the second client "Shell" for the "Site 1", re-launching a new instance of class  it.javac.Shell  using  the following parameters and values: -Xmx64m-Xms64m-Dcom.sun.management.jmxremote -Dtangosol.coherence.management=all -Dtangosol.coherence.management.remote=true -Dtangosol.coherence.distributed.localstorage=false -Dtangosol.coherence.cacheconfig=config/site1-shell-prod-cache-config.xml-Dtangosol.coherence.clusterport=9001-Dtangosol.coherence.site=Site1  And now, let’s execute some tests to validate and better understand our configuration. TEST 1The purpose of this test is to load the objects into the "Site 1" cache and seeing how many objects are cached on the "Site Cloud". Within the "Shell" launched with parameters to access the "Site 1", let’s write and run the command: load test/100 Within the "Shell" launched with parameters to access the "Site Cloud" let’s write and run the command: size passive-cache Expected result If all is OK, the first "Shell" has uploaded 100 objects into a cache named "test"; consequently the "push-replication" functionality has updated the "Site Cloud" by sending the 100 objects to the second cluster where they will have been posted into a respective cache, which we named "passive-cache". TEST 2The purpose of this test is to listen to deleting and adding events happening on the "Site 1" and that are replicated within the cache on "Cloud Site". In the "Shell" launched with parameters to access the "Site Cloud" let’s write and run the command: listen passive-cache/name like '%' or a "cohql" query, with your preferred parameters In the "Shell" launched with parameters to access the "Site 1" let’s write and run the following commands: load test/10 load test2/20 delete test/50 Expected result If all is OK, the "Shell" to Site Cloud let us to listen to all the add and delete events within the cache "cache-passive", whose objects satisfy the query condition "name like '%' " (ie, every objects in the cache; you could change the tests and create different queries).Through the Shell to "Site 1" we launched the commands to add and to delete objects on different caches (test and test2). With the "Shell" running on "Site Cloud" we got the evidence (displayed or printed, or in a log file) that its cache has been filled with events and related objects generated by commands executed from the" Shell "on" Site 1 ", thanks to "push-replication" feature.  Other tests can be performed, such as, for example, the subscription to the events on the "Site 1" too, using different "cohql" queries, changing the cache configuration,  to effectively demonstrate both the potentiality and  the versatility produced by these different configurations, even in the cloud, as in our case. More information on how to configure Coherence "Push Replication" can be found in the Oracle Coherence Incubator project documentation at the following link: http://coherence.oracle.com/display/INC10/Home More information on Oracle Coherence "In Memory Data Grid" can be found at the following link: http://www.oracle.com/technetwork/middleware/coherence/overview/index.html To download and execute the whole sources and configurations of the example explained in the above post,  click here to download them; After download the last available version of the Push-Replication Pattern library implementation from the Oracle Coherence Incubator site, and download also the related and required version of Oracle Coherence. For simplicity the required .jarS to execute the example (that can be found into the Push-Replication-Pattern  download and Coherence Distribution download) are: activemq-core-5.3.1.jar activemq-protobuf-1.0.jar aopalliance-1.0.jar coherence-commandpattern-2.8.4.32329.jar coherence-common-2.2.0.32329.jar coherence-eventdistributionpattern-1.2.0.32329.jar coherence-functorpattern-1.5.4.32329.jar coherence-messagingpattern-2.8.4.32329.jar coherence-processingpattern-1.4.4.32329.jar coherence-pushreplicationpattern-4.0.4.32329.jar coherence-rest.jar coherence.jar commons-logging-1.1.jar commons-logging-api-1.1.jar commons-net-2.0.jar geronimo-j2ee-management_1.0_spec-1.0.jar geronimo-jms_1.1_spec-1.1.1.jar http.jar jackson-all-1.8.1.jar je.jar jersey-core-1.8.jar jersey-json-1.8.jar jersey-server-1.8.jar jl1.0.jar kahadb-5.3.1.jar miglayout-3.6.3.jar org.osgi.core-4.1.0.jar spring-beans-2.5.6.jar spring-context-2.5.6.jar spring-core-2.5.6.jar spring-osgi-core-1.2.1.jar spring-osgi-io-1.2.1.jar At this URL could be found the original article: http://blogs.oracle.com/slc/coherence_into_the_cloud_boost Authors: Nino Guarnacci & Francesco Scarano

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  • Message Queue: Which one is the best scenario?

    - by pandaforme
    I write a web crawler. The crawler has 2 steps: get a html page then parse the page I want to use message queue to improve performance and throughput. I think 2 scenarios: scenario 1: structure: urlProducer -> queue1 -> urlConsumer -> queue2 -> parserConsumer urlProducer: get a target url and add it to queue1 urlConsumer: according to the job info, get the html page and add it to queue2 parserConsumer: according to the job info, parse the page scenario 2: structure: urlProducer -> queue1 -> urlConsumer parserProducer-> queue2 -> parserConsumer urlProducer : get a target url and add it to queue1 urlConsumer: according to the job info, get the html page and write it to db parserProducer: get the html page from db and add it to queue2 parserConsumer: according to the job info, parse the page There are multiple producers or consumers in each structure. scenario1 likes a chaining call. It's difficult to find the point of problem, when occurring errors. scenario2 decouples queue1 and queue2. It's easy to find the point of problem, when occurring errors. I'm not sure the notion is correct. Which one is the best scenario? Or other scenarios? Thanks~

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  • An ideal way to decode JSON documents in C?

    - by AzizAG
    Assuming I have an API to consume that uses JSON as a data transmission method, what is an ideal way to decode the JSON returned by each API resource? For example, in Java I'd create a class for each API resource then initiate an object of that class and consume data from it. for example: class UserJson extends JsonParser { public function UserJson(String document) { /*Initial document parsing goes here...*/ } //A bunch of getter methods . . . . } The probably do something like this: UserJson userJson = new UserJson(jsonString);//Initial parsing goes in the constructor String username = userJson.getName();//Parse JSON name property then return it as a String. Or when using a programming language with associative arrays(i.e., hash table) the decoding process doesn't require creating a class: (PHP) $userJson = json_decode($jsonString);//Decode JSON as key=>value $username = $userJson['name']; But, when I'm programming in procedural programming languages (C), I can't go with either method, since C is neither OOP nor supports associative arrays(by default, at least). What is the "correct" method of parsing pre-defined JSON strings(i.e., JSON documents specified by the API provider via examples or documentation)? The method I'm currently using is creating a file for each API resource to parse, the problem with this method is that it's basically a lousy version of the OOP method, as it looks exactly like the OOP method but doesn't provide any OOP benefits(e.g., can't pass an object of the parser, etc.). I've been thinking about encapsulating each API resource parser file in a publicly accessed structure(pointing all functions/publicly usable variables to the structure) then accessing the parser file code from within the structure(parser.parse(), parser.getName(), etc.). As this way looks a bit better than the my current method, it still just a rip off the OOP way, isn't it? Any suggestions for methods to parse JSON documents on procedural programming lanauges? Any comments on the methods I'm currently using(either 3 of them)?

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  • Crawling a Content Folio

    - by Kyle Hatlestad
    Content Folios in WebCenter Content allow you to assemble, track, and access a logical group of documents and/or links.  It allows you to manage them as just a list of items (simple folio) or organized as a hierarchy (advanced folio).  The built-in UI in content server allows you to work with these folios, but publishing them or consuming them externally can be a bit of a challenge.   The folios themselves are actually XML files that contain the structure, attributes, and pointers to the content items.  So to publish this somewhere, such as a Site Studio page, you could perhaps use an XML parser to traverse the structure and create your output.  But XML parsers are not always the easiest or most efficient to use.  In order to more easily crawl and consume a Content Folio, Ed Bryant - Principal Sales Consultant, wrote a component to do just that.  His component adds a service which does all the work for you and returns the folio structure as a simple resultset.  So consuming and publishing that folio on a Site Studio page or in your portal using RIDC is a breeze!  For example, let's take an advanced Content Folio example like this: If we look at the native file, the XML looks like this: But if we access the folio using the new service - http://server/cs/idcplg?IdcService=FOLIO_CRAWL&dDocName=ecm008003&IsPageDebug=1 - this is what the result set looks like (using the IsPageDebug parameter). Given this as the result set, it makes it very easy to consume and repurpose that folio. You can download a copy of the sample component here. Special thanks to Ed for letting me share this component!

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  • Why is a small fixed vocabulary seen as an advantage to RESTful services?

    - by Matt Esch
    So, a RESTful service has a fixed set of verbs in its vocabulary. A RESTful web service takes these from the HTTP methods. There are some supposed advantages to defining a fixed vocabulary, but I don't really grasp the point. Maybe someone can explain it. Why is a fixed vocabulary as outlined by REST better than dynamically defining a vocabulary for each state? For example, object oriented programming is a popular paradigm. RPC is described to define fixed interfaces, but I don't know why people assume that RPC is limited by these contraints. We could dynamically specify the interface just as a RESTful service dynamically describes its content structure. REST is supposed to be advantageous in that it can grow without extending the vocabulary. RESTful services grow dynamically by adding more resources. What's so wrong about extending a service by dynamically specifying a per-object vocabulary? Why don't we just use the methods that are defined on our objects as the vocabulary and have our services describe to the client what these methods are and whether or not they have side effects? Essentially I get the feeling that the description of a server side resource structure is equivalent to the definition of a vocabulary, but we are then forced to use the limited vocabulary in which to interact with these resources. Does a fixed vocabulary really decouple the concerns of the client from the concerns of the server? I surely have to be concerned with some configuration of the server, this is normally resource location in RESTful services. To complain at the use of a dynamic vocabulary seems unfair because we have to dynamically reason how to understand this configuration in some way anyway. A RESTful service describes the transitions you are able to make by identifying object structure through hypermedia. I just don't understand what makes a fixed vocabulary any better than any self-describing dynamic vocabulary, which could easily work very well in an RPC-like service. Is this just a poor reasoning for the limiting vocabulary of the HTTP protocol?

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  • Benefits of classic OOP over Go-like language

    - by tylerl
    I've been thinking a lot about language design and what elements would be necessary for an "ideal" programming language, and studying Google's Go has led me to question a lot of otherwise common knowledge. Specifically, Go seems to have all of the interesting benefits from object oriented programming without actually having any of the structure of an object oriented language. There are no classes, only structures; there is no class/structure inheritance -- only structure embedding. There aren't any hierarchies, no parent classes, no explicit interface implementations. Instead, type casting rules are based on a loose system similar to duck-typing, such that if a struct implements the necessary elements of a "Reader" or a "Request" or an "Encoding", then you can cast it and use it as one. Does such a system obsolete the concept of OOP? Or is there something about OOP as implemented in C++ and Java and C# that is inherently more capable, more maintainable, somehow more powerful that you have to give up when moving to a language like Go? What benefit do you have to give up to gain the simplicity that this new paradigm represents?

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  • Google analytics - drop in traffic

    - by Andy
    Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

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  • Google analytics - drop in traffic

    - by user1001421
    Bit of a general question here. We are in the process of converting a number of our clients from older web sites to new ones. The problem we are getting, and sorry for being so general here, is we are getting a sharp decline in traffic as reported on Google Analytics. It's not a gradual decline, it seems to hit almost as soon as the new site goes live. I've just got a few questions to see if there is something we are doing wrong: a) We are using the same analytics accounts going from old to new site. Is this a bad idea? b) The actual analytics code is integrated into the pages using a server-side include. IS this a bad idea? c) We structure our sites differently to our old site. IE. The old sites would pretty must have all the web pages in the root directory, and hyperlinks would be linked to the page files: EG. <a href="somepage.aspx">Link</a> Our new sites now have a directory structure that pretty much reflects the navigation structure, and hyper links link to the pages directory instead of the actual page: EG. <a href="/new-items/shoes/">New shoes</a> Is this a bad idea. I'm really searching for a needle in a haystack here. Would appriciate any help or advice as to why we are getting such a sharp and sudden drop in traffic. Again, so this is such a general question. Thanks in advance.

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  • New Book - Oracle ADF Enterprise Application Development Made Simple

    - by Shay Shmeltzer
    It's nice to see another ADF book out there, this one from Sten Vesteli titled "Oracle ADF Enterprise Application Development Made Simple" comes from Packet Publishing Unlike other ADF books out there, this one doesn't aim to teach you Oracle ADF, but rather focuses on the right way to structure and manage a project that leverages ADF. This is a welcomed addition to the bookshelf for people who are looking into ADF based development. One thing I find is that some organization just start developing an ADF application without first doing much planning, something that is understandable given that it is very easy to start building a prototype with ADF and then just grow it into a full blown application. However, as the book points out, doing a bit of planning before you delve into the actual project development can save you a lot of time in the future. For example it is much better to have the right breakdown and structure of your project to allow you to do efficient team development right out of the gate, then to find out 1 year down the road that you are dealing with one monolithic size project which is hard to manage. The book touches on such topics as project organization (workspaces, projects, packages), planning your infrastructure (templates, framework classes), coding standards, team structure, etc. It also covers various aspects of application lifecycle management such as versioning, build, testing, deployment and managing requirements and tasks and how all of those are done when using JDeveloper and Oracle ADF. It's nice to see that the book covers working with Oracle Team Productivity Center - a solution that might not be getting the exposure it deserves. The book also has some chapters about security, internalization and customization of applications both with MDS and with ADF Faces skins (and it even covers the brand new skin editor). Overall I think this is definitely a book you should read if you are about to start your way on a new enterprise scale ADF application. Taking into account the topics that the book discusses before you start your work will save you time and effort down the road. By the way, don't forget that as an OTN member you can get discount on this and other books.

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  • Why the clip space in OpenGL has 4 dimensions?

    - by user827992
    I will use this as a generic reference, but the more i browser online docs and books, the less i understand about this. const float vertexPositions[] = { 0.75f, 0.75f, 0.0f, 1.0f, 0.75f, -0.75f, 0.0f, 1.0f, -0.75f, -0.75f, 0.0f, 1.0f, }; in this online book there is an example about how to draw the first and classic hello world for OpenGL about making a triangle. The vertex structure for the triangle is declared as stated in the code above. The book, as all the other sources about this, stress the point that the Clip Space is a 4D structure that is used to basically decide what will be rasterized and rendered to the screen. Here I have my questions: i can't imagine something in 4D, i don't think that a human can do that, what is a 4D for this Clip space ? the most human-readable doc that i have read speaks about a camera, which is just an abstraction over the clipping concept, and i get that, the problem is, why not using the concept of a camera in the first place which is a more familiar 3D structure? The only problem with the concept of a camera is that you need to define the prospective in other way and so you basically have to add another statement about what kind of camera you wish to have. How i'm supposed to read this 0.75f, 0.75f, 0.0f, 1.0f ? All i get is that they are all float values and i get the meaning of the first 3 values, what does it mean the last one?

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

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

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  • Multiple URL's going to same page - Kosher for Google?

    - by Ashoka15
    I hear conflicting answers from people about this, and I'm a developer by trade, and my SEO knowledge is not what it should be. Here's my situation: I run a website that lists hotels, restaurants, bars, shops, etc for a small Asian beach town. Lots of establishments here are hotels with a restaurant and bar, as well as restaurants that are also bars. As en example, a Mexican restaurant that also functions as a full cocktail bar. I first set it up so each establishment has one page, but can create multiple pages based on their other areas of business. This forces people to create TWO listings under the same name, and most just add the exact same information onto each page, making things redundant. I am re-arranging the database so that a establishment has only ONE listing (one unique page referenced by the unique code '12345ABCDEF') that is accessible from browsing under "Restaurants" and "Bars", and has the URL structures: site.com/dining/mexican/12345ABCDEF/business-name.html site.com/bars/cocktail_bars/12345ABCDEF/business-name.html I could easily simplify the URL to just the unique code and name: site.com/12345ABCDEF/business-name.html But, I found that Google has parsed by URL structure and lists like this on their SERP: Home > Dining > Mexican With each pointing to the default page for homepage, restaurants and Mexican restaurants. If I simplify the URL structure, will I lose these associations? Could Google also be picking up this structure from my breadcrumb trail at the top of the page? What is the best way to set up URL's on these pages so I am not penalized by Google for having identical information on two URL's, while still being able to have places show up as they did with the old system?

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  • OOP Design: relationship between entity classes

    - by beginner_
    I have at first sight a simple issue but can't wrap my head around on how to solve. I have an abstract class Compound. A Compound is made up of Structures. Then there is also a Container which holds 1 Compound. A "special" implementation of Compound has Versions. For that type of Compound I want the Container to hold the Versionof the Compound and not the Compound itself. You could say "just create an interface Containable" and a Container holds 1 Containable. However that won't work. The reason is I'm creating a framework and the main part of that framework is to simplify storing and especially searching for special data type held by Structure objects. Hence to search for Containers which contain a Compound made up of a specific Structure requires that the "Path" from Containerto Structure is well defined (Number of relationships or joins). I hope this was understandable. My question is how to design the classes and relationships to be able to do what I outlined.

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  • Store scores for players and produce a high score list

    - by zrvan
    This question is derived from an interview question that I got for a job I was declined. I have asked for code review for my solution at the dedicated Stack Exchange site. But I hope this question is sufficiently rephrased and asked with a different motivation not to be a duplicate of the other question. Consider the following scenario: You should store player scores in the server back end of a game. The server is written in Java. Every score should be registered, that is, one player may have any number of scores for any number of levels. A high score list should be produced with the fifteen top scores for a given level, but only one score per user (to the effect that even if player X has the two highest scores for level Y, only the first position is counted and player Z has the second place). No information should be persisted and only Java 1.7+ standard libraries should be used. No third party libraries or frameworks are acceptable. With the number of players as the primary factor, what would be the best data structure in terms of scalability and concurrency? How would you access the structure to register a single score given a level and a player id? How would you access the structure to compile the high score list?

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