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• Oracle WebCenter Portal: Pagelet Producer – What’s New in 11.1.1.6.0 Release

  - by kellsey.ruppel

  Igor Plyakov, Sr. Principal Product Marketing Manager is back to share what's new in Oracle WebCenter Portal: Pagelet Producer. In February 2012 Oracle released 11g Release 1 (11.1.1.6.0) for WebCenter Portal. Pagelet Producer (aka Ensemble) that came out with this release added support for several new capabilities that are described in this post. As of 11.1.1.5.0 release the Pagelet Producer can expose WSRP and JPDK portlets as pagelets that can then be consumed in any portal or any third-party application that does not have a WSRP consumer. Now Pagelet Producer team is working on simplifying use of pagelets in WebCenter Sites. To expose WSRP portlets a new Producer should be registered with Pagelet Producer which can be done using Enterprise Manager, WLST or the Pagelet Producer Administration Console (for details see Section 25.9 of Administrator’s Guide for Oracle WebCenter Portal). If the producer requires authentication, Pagelet Producer allows you to select and use one of standard WSS token profiles.  After registration is finished a new resource is created and automatically populated with pagelets that represent the portlets associated with the WSRP endpoint.  For 11.1.1.6.0 release we completed extensive testing of consuming all WebCenter Services that are exposed as WSRP portlets by E2.0 Producer and delivery them as pagelets to WebCenter Interaction portal. In Pagelet Producer 11.1.1.6.0 release we added OpenSocial container that allows consuming gadgets from other OpenSocial containers, e.g. iGoogle, and expose them as pagelets. You can also use Pagelet Producer to host OpenSocial gadgets that could leverage OpenSocial APIs that it supports – People, Activities, Appdata and Pub-Sub features. Note that People and Activities expose the People Connections and Activity Stream from WebCenter Portal, i.e. to use these features Pagelet Producer requires connection to WebCenter Portal schema. Pub-Sub allows leveraging OpenAJAX Hub API for inter-gadget communication. In addition to these major new additions in Pagelet Producer 11.1.1.6.0 release we also extended several functional modules: The Clipping module was extended to support clipping of multiple regions on web resource page and then re-assembly of these separately clipped regions into a single pagelet. The auto-login feature can now be applied to web resources protected with Kerberos authentication; you would find this new functionality handy for consuming SharePoint web parts The logging module now supports full HTTP traffic between the Pagelet Producer and proxied web resource. At last, as the rest of WebCenter Portal stack the Pagelet Producer 11.1.1.6.0 can run on IBM WebSphere Application Server.

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• Tips on Migrating from AquaLogic .NET Accelerator to WebCenter WSRP Producer for .NET

  - by user647124

  This year I embarked on a journey to migrate a group of ASP.NET web applications developed to integrate with WebLogic Portal 9.2 via the AquaLogic® Interaction .NET Application Accelerator 1.0 to instead use the Oracle WebCenter WSRP Producer for .NET and integrated with WebLogic Portal 10.3.4. It has been a very winding path and this blog entry is intended to share both the lessons learned and relevant approaches that led to those learnings. Like most journeys of discovery, it was not a direct path, and there are notes to let you know when it is practical to skip a section if you are in a hurry to get from here to there. For the Curious From the perspective of necessity, this section would be better at the end. If it were there, though, it would probably be read by far fewer people, including those that are actually interested in these types of sections. Those in a hurry may skip past and be none the worst for it in dealing with the hands-on bits of performing a migration from .NET Accelerator to WSRP Producer. For others who want to talk about why they did what they did after they did it, or just want to know for themselves, enjoy. A Brief (and edited) History of the WSRP for .NET Technologies (as Relevant to the this Post) Note: This section is for those who are curious about why the migration path is not as simple as many other Oracle technologies. You can skip this section in its entirety and still be just as competent in performing a migration as if you had read it. The currently deployed architecture that was to be migrated and upgraded achieved initial integration between .NET and J2EE over the WSRP protocol through the use of The AquaLogic Interaction .NET Application Accelerator. The .NET Accelerator allowed the applications that were written in ASP.NET and deployed on a Microsoft Internet Information Server (IIS) to interact with a WebLogic Portal application deployed on a WebLogic (J2EE application) Server (both version 9.2, the state of the art at the time of its creation). At the time this architectural decision for the application was made, both the AquaLogic and WebLogic brands were owned by BEA Systems. The AquaLogic brand included products acquired by BEA through the acquisition of Plumtree, whose flagship product was a portal platform available in both J2EE and .NET versions. As part of this dual technology support an adaptor was created to facilitate the use of WSRP as a communication protocol where customers wished to integrate components from both versions of the Plumtree portal. The adapter evolved over several product generations to include a broad array of both standard and proprietary WSRP integration capabilities. Later, BEA Systems was acquired by Oracle. Over the course of several years Oracle has acquired a large number of portal applications and has taken the strategic direction to migrate users of these myriad (and formerly competitive) products to the Oracle WebCenter technology stack. As part of Oracle’s strategic technology roadmap, older portal products are being schedule for end of life, including the portal products that were part of the BEA acquisition. The .NET Accelerator has been modified over a very long period of time with features driven by users of that product and developed under three different vendors (each a direct competitor in the same solution space prior to merger). The Oracle WebCenter WSRP Producer for .NET was introduced much more recently with the key objective to specifically address the needs of the WebCenter customers developing solutions accessible through both J2EE and .NET platforms utilizing the WSRP specifications. The Oracle Product Development Team also provides these insights on the drivers for developing the WSRP Producer: ***************************************** Support for ASP.NET AJAX. Controls using the ASP.NET AJAX script manager do not function properly in the Application Accelerator for .NET. Support 2 way SSL in WLP. This was not possible with the proxy/bridge set up in the existing Application Accelerator for .NET. Allow developers to code portlets (Web Parts) using the .NET framework rather than a proprietary framework. Developers had to use the Application Accelerator for .NET plug-ins to Visual Studio to manage preferences and profile data. This is now replaced with the .NET Framework Personalization (for preferences) and Profile providers. The WSRP Producer for .NET was created as a new way of developing .NET portlets. It was never designed to be an upgrade path for the Application Accelerator for .NET. .NET developers would create new .NET portlets with the WSRP Producer for .NET and leave any existing .NET portlets running in the Application Accelerator for .NET. ***************************************** The advantage to creating a new solution for WSRP is a product that is far easier for Oracle to maintain and support which in turn improves quality, reliability and maintainability for their customers. No changes to J2EE applications consuming the WSRP portlets previously rendered by the.NET Accelerator is required to migrate from the Aqualogic WSRP solution. For some customers using the .NET Accelerator the challenge is adapting their current .NET applications to work with the WSRP Producer (or any other WSRP adapter as they are proprietary by nature). Part of this adaptation is the need to deploy the .NET applications as a child to the WSRP producer web application as root. Differences between .NET Accelerator and WSRP Producer Note: This section is for those who are curious about why the migration is not as pluggable as something such as changing security providers in WebLogic Server. You can skip this section in its entirety and still be just as competent in performing a migration as if you had read it. The basic terminology used to describe the participating applications in a WSRP environment are the same when applied to either the .NET Accelerator or the WSRP Producer: Producer and Consumer. In both cases the .NET application serves as what is referred to as a WSRP environment as the Producer. The difference lies in how the two adapters create the WSRP translation of the .NET application. The .NET Accelerator, as the name implies, is meant to serve as a quick way of adding WSRP capability to a .NET application. As such, at a high level, the .NET Accelerator behaves as a proxy for requests between the .NET application and the WSRP Consumer. A WSRP request is sent from the consumer to the .NET Accelerator, the.NET Accelerator transforms this request into an ASP.NET request, receives the response, then transforms the response into a WSRP response. The .NET Accelerator is deployed as a stand-alone application on IIS. The WSRP Producer is deployed as a parent application on IIS and all ASP.NET modules that will be made available over WSRP are deployed as children of the WSRP Producer application. In this manner, the WSRP Producer acts more as a Request Filter than a proxy in the WSRP transactions between Producer and Consumer. Highly Recommended Enabling Logging Note: You can skip this section now, but you will most likely want to come back to it later, so why not just read it now? Logging is very helpful in tracking down the causes of any anomalies during testing of migrated portlets. To enable the WSRP Producer logging, update the Application_Start method in the Global.asax.cs for your .NET application by adding log4net.Config.XmlConfigurator.Configure(); IIS logs will usually (in a standard configuration) be in a sub folder under C:\WINDOWS\system32\LogFiles\W3SVC. WSRP Producer logs will be found at C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault\Logs\WSRPProducer.log InputTrace.webinfo and OutputTrace.webinfo are located under C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault and can be useful in debugging issues related to markup transformations. Things You Must Do Merge Web.Config Note: If you have been skipping all the sections that you can, now is the time to stop and pay attention J Because the existing .NET application will become a sub-application to the WSRP Producer, you will want to merge required settings from the existing Web.Config to the one in the WSRP Producer. Use the WSRP Producer Master Page The Master Page installed for the WSRP Producer provides common, hiddenform fields and JavaScripts to facilitate portlet instance management and display configuration when the child page is being rendered over WSRP. You add the Master Page by including it in the <@ Page declaration with MasterPageFile="~/portlets/Resources/MasterPages/WSRP.Master" . You then replace: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" > <HTML> <HEAD> With <asp:Content ID="ContentHead1" ContentPlaceHolderID="wsrphead" Runat="Server"> And </HEAD> <body> <form id="theForm" method="post" runat="server"> With </asp:Content> <asp:Content ID="ContentBody1" ContentPlaceHolderID="Main" Runat="Server"> And finally </form> </body> </HTML> With </asp:Content> In the event you already use Master Pages, adapt your existing Master Pages to be sub masters. See Nested ASP.NET Master Pages for a detailed reference of how to do this. It Happened to Me, It Might Happen to You…Or Not Watch for Use of Session or Request in OnInit In the event the .NET application being modified has pages developed to assume the user has been authenticated in an earlier page request there may be direct or indirect references in the OnInit method to request or session objects that may not have been created yet. This will vary from application to application, so the recommended approach is to test first. If there is an issue with a page running as a WSRP portlet then check for potential references in the OnInit method (including references by methods called within OnInit) to session or request objects. If there are, the simplest solution is to create a new method and then call that method once the necessary object(s) is fully available. I find doing this at the start of the Page_Load method to be the simplest solution. Case Sensitivity .NET languages are not case sensitive, but Java is. This means it is possible to have many variations of SRC= and src= or .JPG and .jpg. The preferred solution is to make these mark up instances all lower case in your .NET application. This will allow the default Rewriter rules in wsrp-producer.xml to work as is. If this is not practical, then make duplicates of any rules where an issue is occurring due to upper or mixed case usage in the .NET application markup and match the case in use with the duplicate rule. For example: <RewriterRule> <LookFor>(href=\"([^\"]+)</LookFor> <ChangeToAbsolute>true</ChangeToAbsolute> <ApplyTo>.axd,.css</ApplyTo> <MakeResource>true</MakeResource> </RewriterRule> May need to be duplicated as: <RewriterRule> <LookFor>(HREF=\"([^\"]+)</LookFor> <ChangeToAbsolute>true</ChangeToAbsolute> <ApplyTo>.axd,.css</ApplyTo> <MakeResource>true</MakeResource> </RewriterRule> While it is possible to write a regular expression that will handle mixed case usage, it would be long and strenous to test and maintain, so the recommendation is to use duplicate rules. Is it Still Relative? Some .NET applications base relative paths with a fixed root location. With the introduction of the WSRP Producer, the root has moved up one level. References to ~/ will need to be updated to ~/portlets and many ../ paths will need another ../ in front. I Can See You But I Can’t Find You This issue was first discovered while debugging modules with code that referenced the form on a page from the code-behind by name and/or id. The initial error presented itself as run-time error that was difficult to interpret over WSRP but seemed clear when run as straight ASP.NET as it indicated that the object with the form name did not exist. Since the form name was no longer valid after implementing the WSRP Master Page, the likely fix seemed to simply update the references in the code. However, as the WSRP Master Page is external to the code, a compile time error resulted: Error      155         The name 'form1' does not exist in the current context                C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault\portlets\legacywebsite\module\Screens \Reporting.aspx.cs                51           52           legacywebsite.module Much hair-pulling research later it was discovered that it was the use of the FindControl method causing the issue. FindControl doesn’t work quite as expected once a Master Page has been introduced as the controls become embedded in controls, require a recursion to find them that is not part of the FindControl method. In code where the page form is referenced by name, there are two steps to the solution. First, the form needs to be referenced in code generically with Page.Form. For example, this: ToggleControl ctrl = new ToggleControl(frmManualEntry, FunctionLibrary.ParseArrayLst(userObj.Roles)); Becomes this: ToggleControl ctrl = new ToggleControl(Page.Form, FunctionLibrary.ParseArrayLst(userObj.Roles)); Generally the form id is referenced in most ASP.NET applications as a path to a control on the form. To reach the control once a MasterPage has been added requires an additional method to recurse through the controls collections within the form and find the control ID. The following method (found at Rick Strahl's Web Log) corrects this very nicely: public static Control FindControlRecursive(Control Root, string Id) { if (Root.ID == Id) return Root; foreach (Control Ctl in Root.Controls) { Control FoundCtl = FindControlRecursive(Ctl, Id); if (FoundCtl != null) return FoundCtl; } return null; } Where the form name is not referenced, simply using the FindControlRecursive method in place of FindControl will be all that is necessary. Following the second part of the example referenced earlier, the method called with Page.Form changes its value extraction code block from this: Label lblErrMsg = (Label)frmRef.FindControl("lblBRMsg" To this: Label lblErrMsg = (Label) FunctionLibrary.FindControlRecursive(frmRef, "lblBRMsg" The Master That Won’t Step Aside In most migrations it is preferable to make as few changes as possible. In one case I ran across an existing Master Page that would not function as a sub-Master Page. While it would probably have been educational to trace down why, the expedient process of updating it to take the place of the WSRP Master Page is the route I took. The changes are highlighted below: … <asp:ContentPlaceHolder ID="wsrphead" runat="server"></asp:ContentPlaceHolder> </head> <body leftMargin="0" topMargin="0"> <form id="TheForm" runat="server"> <input type="hidden" name="key" id="key" value="" /> <input type="hidden" name="formactionurl" id="formactionurl" value="" /> <input type="hidden" name="handle" id="handle" value="" /> <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" > </asp:ScriptManager> This approach did not work for all existing Master Pages, but fortunately all of the other existing Master Pages I have run across worked fine as a sub-Master to the WSRP Master Page. Moving On In Enterprise Portals, even after you get everything working, the work is not finished. Next you need to get it where everyone will work with it. Migration Planning Providing that the server where IIS is running is adequately sized, it is possible to run both the .NET Accelerator and the WSRP Producer on the same server during the upgrade process. The upgrade can be performed incrementally, i.e., one portlet at a time, if server administration processes support it. Those processes would include the ability to manage a second producer in the consuming portal and to change over individual portlet instances from one provider to the other. If processes or requirements demand that all portlets be cut over at the same time, it needs to be determined if this cut over should include a new producer, updating all of the portlets in the consumer, or if the WSRP Producer portlet configuration must maintain the naming conventions used by the .NET Accelerator and simply change the WSRP end point configured in the consumer. In some enterprises it may even be necessary to maintain the same WSDL end point, at which point the IIS configuration will be where the updates occur. The downside to such a requirement is that it makes rolling back very difficult, should the need arise. Location, Location, Location Not everyone wants the web application to have the descriptively obvious wsrpdefault location, or needs to create a second WSRP site on the same server. The instructions below are from the product team and, while targeted towards making a second site, will work for creating a site with a different name and then remove the old site. You can also change just the name in IIS. Manually Creating a WSRP Producer Site Instructions (NOTE: all executables used are the same ones used by the installer and “wsrpdev” will be the name of the new instance): 1. Copy C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdefault to C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev. 2. Bring up a command window as an administrator 3. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\IISAppAccelSiteCreator.exe install WSRPProducers wsrpdev "C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev" 8678 2.0.50727 4. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\PermManage.exe add FileSystem C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev "NETWORK SERVICE" 3 1 5. Run C:\Oracle\Middleware\WSRPProducerForDotNet\uninstall_resources\PermManage.exe add FileSystem C:\Oracle\Middleware\WSRPProducerForDotNet\wsrpdev EVERYONE 1 1 6. Open up C:\Oracle\Middleware\WSRPProducerForDotNet\wsdl\1.0\WSRPService.wsdl and replace wsrpdefault with wsrpdev 7. Open up C:\Oracle\Middleware\WSRPProducerForDotNet\wsdl\2.0\WSRPService.wsdl and replace wsrpdefault with wsrpdev Tests: 1. Bring up a browser on the host itself and go to http://localhost:8678/wsrpdev/wsdl/1.0/WSRPService.wsdl and make sure that the URLs in the XML returned include the wsrpdev changes you made in step 6. 2. Bring up a browser on the host itself and see if the default sample comes up: http://localhost:8678/wsrpdev/portlets/ASPNET_AJAX_sample/default.aspx 3. Register the producer in WLP and test the portlet. Changing the Port used by WSRP Producer The pre-configured port for the WSRP Producer is 8678. You can change this port by updating both the IIS configuration and C:\Oracle\Middleware\WSRPProducerForDotNet\[WSRP_APP_NAME]\wsdl\1.0\WSRPService.wsdl. Do You Need to Migrate? Oracle Premier Support ended in November of 2010 for AquaLogic Interaction .NET Application Accelerator 1.x and Extended Support ends in November 2012 (see http://www.oracle.com/us/support/lifetime-support/lifetime-support-software-342730.html for other related dates). This means that integration with products released after November of 2010 is not supported. If having such support is the policy within your enterprise, you do indeed need to migrate. If changes in your enterprise cause your current solution with the .NET Accelerator to no longer function properly, you may need to migrate. Migration is a choice, and if the goals of your enterprise are to take full advantage of newer technologies then migration is certainly one activity you should be planning for.

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• Producer and Consumer Threads Hang

  - by user972425

  So this is my first foray into threads and thus far it is driving me insane. My problem seems to be some kind of synchronization error that causes my consumer thread to hang. I've looked at other code and just about everything I could find and I can't find what my error is. There also seems to be a discrepancy between the code being executed in Eclipse and via javac in the command line. Intention - Using a bounded buffer (with 1000 slots) create and consume 1,000,000 doubles. Use only notify and wait. Problem - In Eclipse the consumer thread will occasionally hang around 940,000 iterations, but other times completes. In the command line the consumer thread always hangs. Output - Eclipse - Successful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. Consumer has consumed 1000000 doubles. Consumer has consumed all items. Exitting Output - Command Line/Eclipse - Unsuccessful Producer has produced 100000 doubles. Consumer has consumed 100000 doubles. Producer has produced 200000 doubles. Consumer has consumed 200000 doubles. Producer has produced 300000 doubles. Consumer has consumed 300000 doubles. Producer has produced 400000 doubles. Consumer has consumed 400000 doubles. Producer has produced 500000 doubles. Consumer has consumed 500000 doubles. Producer has produced 600000 doubles. Consumer has consumed 600000 doubles. Producer has produced 700000 doubles. Consumer has consumed 700000 doubles. Producer has produced 800000 doubles. Consumer has consumed 800000 doubles. Producer has produced 900000 doubles. Consumer has consumed 900000 doubles. Producer has produced 1000000 doubles. Producer has produced all items. At this point it just sits and hangs. Any help you can provide about where I might have misstepped is greatly appreciated. Code - Producer thread import java.text.DecimalFormat;+ " doubles. Cumulative value of generated items= " + temp) import java.util.*; import java.io.*; public class producer implements Runnable{ private buffer produceBuff; public producer (buffer buff){ produceBuff = buff; } public void run(){ Random random = new Random(); double temp = 0, randomElem; DecimalFormat df = new DecimalFormat("#.###"); for(int i = 1; i<=1000000; i++) { randomElem = (Double.parseDouble( df.format(random.nextDouble() * 100.0))); try { produceBuff.add(randomElem); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } temp+= randomElem; if(i%100000 == 0) {produceBuff.print("Producer has produced "+ i ); } } produceBuff.print("Producer has produced all items."); } } Consumer thread import java.util.*; import java.io.*; public class consumer implements Runnable{ private buffer consumBuff; public consumer (buffer buff){ consumBuff = buff; } public void run(){ double temp = 0; for(int i = 1; i<=1000000; i++) { try { temp += consumBuff.get(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } if(i%100000 == 0) {consumBuff.print("Consumer has consumed "+ i ); //if(i>999000) //{System.out.println("Consuming item " + i);} } consumBuff.print("Consumer has consumed all items."); } } Buffer/Main import java.util.*; import java.io.*; public class buffer { private double buff[]; private int addPlace; private int getPlace; public buffer(){ buff = new double[1000]; addPlace = 0; getPlace = 0; } public synchronized void add(double add) throws InterruptedException{ if((addPlace+1 == getPlace) ) { try { wait(); } catch (InterruptedException e) {throw e;} } buff[addPlace] = add; addPlace = (addPlace+1)%1000; notify(); } public synchronized double get()throws InterruptedException{ if(getPlace == addPlace) { try { wait(); } catch (InterruptedException e) {throw e;} } double temp = buff[getPlace]; getPlace = (getPlace+1)%1000; notify(); return temp; } public synchronized void print(String view) { System.out.println(view); } public static void main(String args[]){ buffer buf = new buffer(); Thread produce = new Thread(new producer(buf)); Thread consume = new Thread(new consumer(buf)); produce.start(); consume.start(); try { produce.join(); consume.join(); } catch (InterruptedException e) {return;} System.out.println("Exitting"); } }

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• Producer-consumer pattern with consumer restrictions

  - by Dan

  I have a processing problem that I am thinking is a classic producer-consumer problem with the two added wrinkles that there may be a variable number of producers and there is the restriction that no more than one item per producer may be consumed at any one time. I will generally have 50-100 producers and as many consumers as CPU cores on the server. I want to maximize the throughput of the consumers while ensuring that there are never more than one work item in process from any single producer. This is more complicated than the classic producer-consumer problem which I think assumes a single producer and no restriction on which work items may be in progress at any one time. I think the problem of multiple producers is relatively easily solved by enqueuing all work items on a single work queue protected by a critical section. I think the restriction on simultaneously processing work items from any single producer is harder because I cannot think of any solution that does not require each consumer to notify some kind of work dispatcher that a particular work item has been completed so as to lift the restriction on work items from that producer. In other words, if Consumer2 has just completed WorkItem42 from Producer53, there needs to be some kind of callback or notification from Consumer2 to a work dispatcher to allow the work dispatcher to release the next work item from Producer53 to the next available consumer (whether Consumer2 or otherwise). Am I overlooking something simple here? Is there a known pattern for this problem? I would appreciate any pointers.

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• Producer/consumer in Grails?

  - by Mulone

  Hi all, I'm trying to implement a Consumer/Producer app in Grails, after several unsuccessful attempts at implementing concurrent threads. Basically I want to store all the events coming from a clients (through separate AJAX calls) in a single queue and then process such a queue in a linear way as soon as new events are added. This looks like a Producer/Consumer problem: http://en.wikipedia.org/wiki/Producer-consumer_problem How can I implement this in Grails (maybe with a timer or even better by generating an event 'process queue')? Basically I'd like to a have a singleton service waiting for new events in the queue and processing them linearly (even if the queue is loaded by several concurrent processes). Any hints? Cheers!

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• Producer Consumer Problem

  Different ways of doing the Producer Consumer Problem

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• [C++] Producer/Consumer Implementation -- Feedback Wanted

  - by bobber205

  I'm preparing for an interview in a few weeks and I thougth I would give threads in boost a go, as well as do the simple producer/consumer problem I learned in school. Haven't done it quite awhile so I was curious what you guys think of this? What should I add to make it a better example etc. Thanks for the feedback! :) ////////////////////////////////////////////////////////////////////////// boost::mutex bufferMutex; deque<int> buffer; const int maxBufferSize = 5; ////////////////////////////////////////////////////////////////////////// bool AddToBuffer(int i) { if (buffer.size() < maxBufferSize) { buffer.push_back(i); return true; } else { return false; } } bool GetFromBuffer(int& toReturn) { if (buffer.size() == 0) { return false; } else { toReturn = buffer[buffer.size()-1]; buffer.pop_back(); return true; } } struct Producer { int ID; void operator()() { while (true) { boost::mutex::scoped_lock lock(bufferMutex); int num = dice(); bool result = AddToBuffer(num); lock.unlock(); //safe area done if (result) { cout << "Producer " << this->ID << " Added " << num << endl; } else { cout << "!!Buffer was Full!!" << endl; } //Added //Now wait boost::xtime xt; xtime_get( &xt, boost::TIME_UTC); xt.nsec += 1000000 + 100000 * (rand() % 1000); boost::thread::sleep(xt); } } }; struct Consumer { int ID; void operator()() { while (true) { int returnedInt = 0; boost::mutex::scoped_lock lock(bufferMutex); bool result = GetFromBuffer(returnedInt); lock.unlock(); //safe area done if (result) { cout << "\tConsumer " << this->ID << " Took Out " << returnedInt << endl; } else { cout << "!!Buffer was Empty!!" << endl; } //Added //Now wait boost::xtime xt; xtime_get( &xt, boost::TIME_UTC); xt.nsec += 1000000 + 100000 * (rand() % 1000); boost::thread::sleep(xt); } } }; void main() { Producer p, p2; Consumer c, c2; p.ID = 1; p2.ID = 2; c.ID = 1; c2.ID = 2; boost::thread thread1(boost::ref(p)); boost::thread thread2(boost::ref(c)); boost::thread thread3(boost::ref(p2)); boost::thread thread4(boost::ref(c2)); int x; cin >> x; }

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• Hello World Pagelet

  - by astemkov

  Introduction The goal of this exercise is to give you a basic feel of how you can use Pagelet Producer to proxy a web page We will proxy a simple static Hello World web page, cut one section out of that page and present it as a pagelet that you can later insert on your own application page or to your portal page such as WebCenter Portal space or WebCenter Interaction community page. Hello World sample app This is the static web page we will work with: Let's assume the following: The Hello World web page is running on server http://appserver.company.com:1234/ The Hello World web page path is: http://appserver.company.com:1234/helloworld/ Initial Pagelet Producer setup Let's assume that the Pagelet Producer server is running on http://pageletserver.company.com:8889/pagelets/ First let's check that Pagelet Producer is up and running. In order to do that we just need to access the following URL: http://pageletserver.company.com:8889/pagelets/ And this is what should be returned: Now you can access Pagelet Producer administration screens using this URL: http://pageletserver.company.com:8889/pagelets/admin This is how the UI looks: Now if you connect to the internet via proxy server, you need to configure proxy in Pagelet Producer settings. In the Navigator pane: Jump To - Settings Click on "Proxy" Enter your proxy server configuration: Creating a resource First thing that you need to do is to create a resource for your web page. This will tell Pagelet Producer that all sub-paths of the web page should be proxied. It also will allow you to setup common rules of how your web page should be proxied and will serve as a container for your pagelets. In the Navigator pane: Jump To - Resources Click on any existing resource (ex. welcome_resource) Click on "Create selected type" toolbar button at the top of the Navigator pane Select "Web" in the "Select Producer Type" dialog box and click "OK" Now after the resource is created let's click on "General" sub-item a specify the following values Name = AppServer Source URL = http://appserver.company.com:1234/ Destination URL = /appserver/ Click on "Save" toolbar button at the top of the Navigator pane After the resource is created our web page becomes accessible by the URL: http://pageletserver.company.com:8889/pagelets/appserver/helloworld/ So in original web page address Source URL is replaced with Pagelet Producer URL (http://pageletserver.company.com:8889/pagelets) + Destination URL Creating a pagelet Now let's create "Hello World" pagelet. Under the resource node activate Pagelets subnode Click on "Create selected type" toolbar button at the top of the Navigator pane Click on "General" sub-node of newly created pagelet and specify the following values Name = Hello_World Library = MyLib Library is used for logical grouping. The portals use the "Library" value to group pagelets in their respective UI's. For example, when adding pagelets to a WebCenter Portal space you would see the individual pagelets listed under the "Library" name. URL Suffix = helloworld/index.html this is where the Hello World page html is served from Click on "Save" toolbar button at the top of the Navigator pane The Library name can be anything you want, it doesn't have to match the resource name at all. It is used as a logical grouping of pagelets, and you can include pagelets from multiple resources into the same library or create a new library for each pagelet. After you save the pagelet you can access it here: http://pageletserver.company.com:8889/pagelets/inject/v2/pagelet/MyLib/Hello_World which is : http://pageletserver.company.com:8889/pagelets/inject/v2/pagelet/ + [Library] + [Name] Or to test the injection of a pagelet into iframe you can click on the pagelets "Documentation" sub-node and use "Access Pagelet using REST" URL: This is what we will see: Clipping The pagelet that we just created covers the whole web page, but we want just the "Hello World" segment of it. So let's clip it. Under the Hello_World pagelet node activate Clipper sub-node Click on "Create selected type" toolbar button at the top of the Navigator pane Specify a Name for newly created clipper. For example: "c1" Click on "Content" sub-node of the clipper Click on "Launch Clipper" button New browser window will open By moving a mouse pointer over the web page select the area you want to clip: Click left mouse button - the browser window will disappear and you will see that Clipping Path was automatically generated Now let's save and access the link from the "Documentation" page again Here's our pagelet nicely clipped and ready for being used on your Web Center Space

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• Why is my producer-consumer blocking?

  - by User007

  My code is here: http://pastebin.com/Fi3h0E0P Here is the output 0 Should we take order today (y or n): y Enter order number: 100 More customers (y or n): n Stop serving customers right now. Passing orders to cooker: There are total of 1 order(s) 1 Roger, waiter. I am processing order #100 The goal is waiter must take orders and then give them to the cook. The waiter has to wait cook finishes all pizza, deliver the pizza, and then take new orders. I asked how P-V work in my previous post here. I don't think it has anything to do with \n consuming? I tried all kinds of combination of wait(), but none work. Where did I make a mistake? The main part is here: //Producer process if(pid > 0) { while(1) { printf("0"); P(emptyShelf); // waiter as P finds no items on shelf; P(mutex); // has permission to use the shelf waiter_as_producer(); V(mutex); // cooker now can use the shelf V(orderOnShelf); // cooker now can pickup orders wait(); printf("2"); P(pizzaOnShelf); P(mutex); waiter_as_consumer(); V(mutex); V(emptyShelf); printf("3 "); } } if(pid == 0) { while(1) { printf("1"); P(orderOnShelf); // make sure there is an order on shelf P(mutex); //permission to work cooker_as_consumer(); // take order and put pizza on shelf printf("return from cooker"); V(mutex); //release permission printf("just released perm"); V(pizzaOnShelf); // pizza is now on shelf printf("after"); wait(); printf("4"); } } So I imagine this is the execution path: enter waiter_as_producer, then go to child process (cooker), then transfer the control back to parent, finish waiter_as_consumer, switch back to child. The two waits switch back to parent (like I said I tried all possible wait() combination...).

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• Consuming Hello World pagelet in WebCenter Spaces

  - by astemkov

  Introduction The goal of this exercise is to show you how can you use Hello World pagelet that you just created from your web space. Assumptions Let's assume the following: Pagelet Producer is running on http://pageletserver.company.com:8889/pagelets/ WebCenter is running on http://webcenter.company.com:8888/webcenter/ You created Hello_World pagelet as described here. For our exercise we will need a space created. So let's login into WebCenter Portal and create a space called "myspace" using "Portal Site" template: Registering Pagelet Producer with WebCenter portal In order to use our newly created pagelet from WebCenter Spaces, we first need to register Pagelet Producer: Click "Administraion" link on WebCenter toolbar Open the "Configuration" tab Click on "Services" link on the upper-left corner of the page Click on "Portlet Producers" link on the right hand pane of the screen Click on "Register" button Select "Pagelet Producer" radio button and type Producer Name = "MyPageletProducer" Server URL = http://pageletserver.company.com:8889/pagelets/ Click "Test" button If everything is succesful you will see the following screen: Now click "OK'. Pagelet producer is registered: Inserting Hello World pagelet to WebCenter Space Now let's insert Hello World pagelet into "myspace" page: Let's go back to "myspace", click on the icon in a upper-right corner of the page and select "Edit Page" Click on one of the "Add Content" buttons: Select "Mash-Ups": Select "Pagelet Producers: You will see the MyPageletProducer that we just registered: Click on it. You will see the library "MyLib" that contains our "Hello_World" pagelet. Click on "MyLib" and you will see "Hello_World" pagelet. Click on "Add" button, and then "Close" button. Click "Save" button, and then "Close". Now we see that our "Hello World" pagelet is inserted into "myspace" page:

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• Java threads, wait time always 00:00:00-Producer/Consumer

  - by user3742254

  I am currently doing a producer consumer problem with a number of threads and have had to set priorities and waits to them to ensure that one thread, the security thread, runs last. I have managed to do this and I have managed to get the buffer working. The last thing that I am required to do is to show the wait time of threads that are too large for the buffer and to calculate the average wait time. I have included code to do so, but everything I run the program, the wait time is always returned as 00:00:00, and by extension, the average is returned as the same. I was speaking to one of my colleagues who said that it is not a matter of the code but rather a matter of the computer needing to work off of one processor, which can be adjusted in the task manager settings. He has an HP like myself but his program prints the wait time 180 times, whereas mine prints usually about 3-7 times and is only 00:00:01 on one instance before finishing when I have made the processor adjustments. My other colleague has an iMac and hers puts out an average of 42:00:34(42 minutes??) I am very confused about this because I can see no difference between our codes and like my colleague said, I was wondering is it a computer issue. I am obviously concerned as I wanted to make sure that my code correctly calculated an average wait time, but that is impossible to tell when the wait times always show as 00:00:00. To calculate the thread duration, including the time it entered and exited the buffer was done by using a timestamp import, and then subtracting start time from end time. Is my code correct for this issue or is there something which is missing? I would be very grateful for any solutions. Below is my code: My buffer class package com.Com813cw; import java.text.DateFormat; import java.text.SimpleDateFormat; /** * Created by Rory on 10/08/2014. */ class Buffer { private int contents, count = 0, process = 200; private int totalRam = 1000; private boolean available = false; private long start, end, wait, request = 0; private DateFormat time = new SimpleDateFormat("ss:SSS"); public int avWaitTime =0; public void average(){ System.out.println("Average Application Request wait time: "+ time.format(request/count)); } public synchronized int get() { while (process <= 500) { try { wait(); } catch (InterruptedException e) { } } process -= 200; System.out.println("CPU After Process " + process); notifyAll(); return contents; } public synchronized void put(int value) { if (process <= 500) { process += value; } else { start = System.currentTimeMillis(); try { wait(); } catch (InterruptedException e) { } end = System.currentTimeMillis(); wait = end - start; count++; request += wait; System.out.println("Application Request Wait Time: " + time.format(wait)); process += value; contents = value; calcWait(wait, count); } notifyAll(); } public void calcWait(long wait, int count){ this.avWaitTime = (int) (wait/count); } public void printWait(){ System.out.println("Wait time is " + time.format(this.avWaitTime)); } } My spotify class package com.Com813cw; import java.sql.Timestamp; /** * Created by Rory on 11/08/2014. */ class Spotify extends Thread { private Buffer buffer; private int number; private int bytes = 250; public Spotify(Buffer c, int number) { buffer = c; this.number = number; } long startTime = System.currentTimeMillis(); public void run() { for (int i = 0; i < 20; i++) { buffer.put(bytes); System.out.println(getName() + this.number + " put: " + bytes + " bytes "); try { sleep(1000); } catch (InterruptedException e) { } } long endTime = System.currentTimeMillis(); long timeTaken = endTime - startTime; java.util.Date date = new java.util.Date(); System.out.println("-----------------------------"); System.out.println("Spotify has finished executing."); System.out.println("Time taken to execute was " + timeTaken + " milliseconds"); System.out.println("Time that Spotify thread exited Buffer was " + new Timestamp(date.getTime())); System.out.println("-----------------------------"); } } My BubbleWitch class package com.Com813cw; import java.lang.*; import java.lang.System; import java.sql.Timestamp; /** * Created by Rory on 10/08/2014. */ class BubbleWitch2 extends Thread { private Buffer buffer; private int number; private int bytes = 100; public BubbleWitch2(Buffer c, int number) { buffer = c; this.number=number ; } long startTime = System.currentTimeMillis(); public void run() { for (int i = 0; i < 10; i++) { buffer.put(bytes); System.out.println(getName() + this.number + " put: " + bytes + " bytes "); try { sleep(1000); } catch (InterruptedException e) { } } long endTime = System.currentTimeMillis(); long timeTaken = endTime - startTime; java.util.Date date = new java.util.Date(); System.out.println("-----------------------------"); System.out.println("BubbleWitch2 has finished executing."); System.out.println("Time taken to execute was " +timeTaken+ " milliseconds"); System.out.println("Time Bubblewitch2 thread exited Buffer was " + new Timestamp(date.getTime())); System.out.println("-----------------------------"); } } My Test class package com.Com813cw; /** * Created by Rory on 10/08/2014. */ public class ProducerConsumerTest { public static void main(String[] args) throws InterruptedException { Buffer c = new Buffer(); BubbleWitch2 p1 = new BubbleWitch2(c,1); Processor c1 = new Processor(c, 1); Spotify p2 = new Spotify(c, 2); SystemManagement p3 = new SystemManagement(c, 3); SecurityUpdate p4 = new SecurityUpdate(c, 4, p1, p2, p3); p1.setName("BubbleWitch2 "); p2.setName("Spotify "); p3.setName("System Management "); p4.setName("Security Update "); p1.setPriority(10); p2.setPriority(10); p3.setPriority(10); p4.setPriority(5); c1.start(); p1.start(); p2.start(); p3.start(); p4.start(); p2.join(); p3.join(); p4.join(); c.average(); System.exit(0); } } My security update package com.Com813cw; import java.lang.*; import java.lang.System; import java.sql.Timestamp; /** * Created by Rory on 11/08/2014. */ class SecurityUpdate extends Thread { private Buffer buffer; private int number; private int bytes = 150; private int process = 0; public SecurityUpdate(Buffer c, int number, BubbleWitch2 bubbleWitch2, Spotify spotify, SystemManagement systemManagement) throws InterruptedException { buffer = c; this.number = number; bubbleWitch2.join(); spotify.join(); systemManagement.join(); } long startTime = System.currentTimeMillis(); public void run() { for (int i = 0; i < 15; i++) { buffer.put(bytes); System.out.println(getName() + this.number + " put: " + bytes + " bytes"); try { sleep(1500); } catch (InterruptedException e) { } } long endTime = System.currentTimeMillis(); long timeTaken = endTime - startTime; java.util.Date date = new java.util.Date(); System.out.println("-----------------------------"); System.out.println("Security Update has finished executing."); System.out.println("Time taken to execute was " + timeTaken + " milliseconds"); System.out.println("Time that SecurityUpdate thread exited Buffer was " + new Timestamp(date.getTime())); System.out.println("------------------------------"); } } I'd be grateful as I said for any help as this is the last and most frustrating obstacle.

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• what's wrong with my producer-consumer queue design?

  - by toasteroven

  I'm starting with the C# code example here. I'm trying to adapt it for a couple reasons: 1) in my scenario, all tasks will be put in the queue up-front before consumers will start, and 2) I wanted to abstract the worker into a separate class instead of having raw Thread members within the WorkerQueue class. My queue doesn't seem to dispose of itself though, it just hangs, and when I break in Visual Studio it's stuck on the _th.Join() line for WorkerThread #1. Also, is there a better way to organize this? Something about exposing the WaitOne() and Join() methods seems wrong, but I couldn't think of an appropriate way to let the WorkerThread interact with the queue. Also, an aside - if I call q.Start(#) at the top of the using block, only some of the threads every kick in (e.g. threads 1, 2, and 8 process every task). Why is this? Is it a race condition of some sort, or am I doing something wrong? using System; using System.Collections.Generic; using System.Text; using System.Messaging; using System.Threading; using System.Linq; namespace QueueTest { class Program { static void Main(string[] args) { using (WorkQueue q = new WorkQueue()) { q.Finished += new Action(delegate { Console.WriteLine("All jobs finished"); }); Random r = new Random(); foreach (int i in Enumerable.Range(1, 10)) q.Enqueue(r.Next(100, 500)); Console.WriteLine("All jobs queued"); q.Start(8); } } } class WorkQueue : IDisposable { private Queue _jobs = new Queue(); private int _job_count; private EventWaitHandle _wh = new AutoResetEvent(false); private object _lock = new object(); private List _th; public event Action Finished; public WorkQueue() { } public void Start(int num_threads) { _job_count = _jobs.Count; _th = new List(num_threads); foreach (int i in Enumerable.Range(1, num_threads)) { _th.Add(new WorkerThread(i, this)); _th[_th.Count - 1].JobFinished += new Action(WorkQueue_JobFinished); } } void WorkQueue_JobFinished(int obj) { lock (_lock) { _job_count--; if (_job_count == 0 && Finished != null) Finished(); } } public void Enqueue(int job) { lock (_lock) _jobs.Enqueue(job); _wh.Set(); } public void Dispose() { Enqueue(Int32.MinValue); _th.ForEach(th = th.Join()); _wh.Close(); } public int GetNextJob() { lock (_lock) { if (_jobs.Count 0) return _jobs.Dequeue(); else return Int32.MinValue; } } public void WaitOne() { _wh.WaitOne(); } } class WorkerThread { private Thread _th; private WorkQueue _q; private int _i; public event Action JobFinished; public WorkerThread(int i, WorkQueue q) { _i = i; _q = q; _th = new Thread(DoWork); _th.Start(); } public void Join() { _th.Join(); } private void DoWork() { while (true) { int job = _q.GetNextJob(); if (job != Int32.MinValue) { Console.WriteLine("Thread {0} Got job {1}", _i, job); Thread.Sleep(job * 10); // in reality would to actual work here if (JobFinished != null) JobFinished(job); } else { Console.WriteLine("Thread {0} no job available", _i); _q.WaitOne(); } } } } }

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• Multimedia How-To: Producer for PowerPoint 2007

  Need a creative boost to your small business marketing materials? Helen Bradley shows how to add multimedia to your presentations with Producer for PowerPoint 2007.

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• Multimedia How-To: Producer for PowerPoint 2007

  Need a creative boost to your small business marketing materials? Helen Bradley shows how to add multimedia to your presentations with Producer for PowerPoint 2007.

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• Unknown error in Producer/Consumer program, believe it to be an infinite loop.

  - by ray2k

  Hello, I am writing a program that is solving the producer/consumer problem, specifically the bounded-buffer version(i believe they mean the same thing). The producer will be generating x number of random numbers, where x is a command line parameter to my program. At the current moment, I believe my program is entering an infinite loop, but I'm not sure why it is occurring. I believe I am executing the semaphores correctly. You compile it like this: gcc -o prodcon prodcon.cpp -lpthread -lrt Then to run, ./prodcon 100(the number of randum nums to produce) This is my code. typedef int buffer_item; #include <stdlib.h> #include <stdio.h> #include <pthread.h> #include <semaphore.h> #include <unistd.h> #define BUFF_SIZE 10 #define RAND_DIVISOR 100000000 #define TRUE 1 //two threads void *Producer(void *param); void *Consumer(void *param); int insert_item(buffer_item item); int remove_item(buffer_item *item); int returnRandom(); //the global semaphores sem_t empty, full, mutex; //the buffer buffer_item buf[BUFF_SIZE]; //buffer counter int counter; //number of random numbers to produce int numRand; int main(int argc, char** argv) { /* thread ids and attributes */ pthread_t pid, cid; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM); numRand = atoi(argv[1]); sem_init(&empty,0,BUFF_SIZE); sem_init(&full,0,0); sem_init(&mutex,0,0); printf("main started\n"); pthread_create(&pid, &attr, Producer, NULL); pthread_create(&cid, &attr, Consumer, NULL); printf("main gets here"); pthread_join(pid, NULL); pthread_join(cid, NULL); printf("main done\n"); return 0; } //generates a randum number between 1 and 100 int returnRandom() { int num; srand(time(NULL)); num = rand() % 100 + 1; return num; } //begin producing items void *Producer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { //sleep for a random period of time int rNum = rand() / RAND_DIVISOR; sleep(rNum); //generate a random number item = returnRandom(); //acquire the empty lock sem_wait(&empty); //acquire the mutex lock sem_wait(&mutex); if(insert_item(item)) { fprintf(stderr, " Producer report error condition\n"); } else { printf("producer produced %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal full */ sem_post(&full); } return NULL; } /* Consumer Thread */ void *Consumer(void *param) { buffer_item item; int i; for(i = 0; i < numRand; i++) { /* sleep for a random period of time */ int rNum = rand() / RAND_DIVISOR; sleep(rNum); /* aquire the full lock */ sem_wait(&full); /* aquire the mutex lock */ sem_wait(&mutex); if(remove_item(&item)) { fprintf(stderr, "Consumer report error condition\n"); } else { printf("consumer consumed %d\n", item); } /* release the mutex lock */ sem_post(&mutex); /* signal empty */ sem_post(&empty); } return NULL; } /* Add an item to the buffer */ int insert_item(buffer_item item) { /* When the buffer is not full add the item and increment the counter*/ if(counter < BUFF_SIZE) { buf[counter] = item; counter++; return 0; } else { /* Error the buffer is full */ return -1; } } /* Remove an item from the buffer */ int remove_item(buffer_item *item) { /* When the buffer is not empty remove the item and decrement the counter */ if(counter > 0) { *item = buf[(counter-1)]; counter--; return 0; } else { /* Error buffer empty */ return -1; } }

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• Clarification about Event Producer in StreamInsight

  - by sandy

  I need a small clarification about streamInsight, I know by doc's that StreamInsight can handle multiple concurrent Events. But will the event producer be a separate function, for ex: I need to watch a folder for new Files becoz all my sensors il write readings every day in a new file in particular drive. Method 1: FileSystemWatcher: These is the traditional approach where we write a service using FileSystemWatcher to watch a folder for new files,etc.. Upon receiving event from FileSystemWatcher il perform some operations on these files. How to do these using streamInsight??? I came know that using IObservable i can push events to StreamInsight. But is there anything to watch folder is sreamInsight like FileSystemWatcher. OR In order to raise events to streamInsight do we need to use FileSystemWacther? Any suggestion regarding these is highly appreciated. Thank in Advance

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• Automating Form Login

  - by Greg_Gutkin

  Introduction A common task in configuring a web application for proxying in Pagelet Producer is setting up form autologin. PP provides a wizard-like tool for detecting the login form fields, but this is usually only the first step in configuring this feature. If the generated configuration doesn't seem to work, some additional manual modifications will be needed to complete the setup. This article will try to guide you through this process while steering you away from common pitfalls. For the purposes of this article, let's assume the following characteristics about your environment: Web Application Base URL: http://host/app (configured as Resource Source URL in PP) Pagelet Producer Base URL: http://pp/pagelets Form Field Auto-Detection Form Autologin is configured in the PP Admin UI under resource_name/Autologin/Form Login. First, you'll enter the URL to the login form under "Login Form Identification". This will enable the admin wizard to connect to and display the login page. Caution: RedirectsMake sure the entered URL matches what you see in the browser's address bar, when the application login page is displayed. For example, even though you may be able to reach the login page by simply typing http://host/app, the URL you end up on may change to http://host/app/login via browser redirect(s).The second URL is the one you will want to use. Caution: External Login ServersThe login page may actually come from a different server than the application you are trying to proxy. For example, you may notice that the login page URL changes to http://hostB/appB. This is common when external SSO products are involved. There are two ways of dealing with this situation. One is to configure Pagelet Producer to participate in SSO. This approach is out of scope of this article and is discussed in a separate whitepaper (TODO add link). The second approach is to use the autologin feature to provide stored credentials to the SSO login form. Since the login form URL is not an extension of the application base URL (PP resource URL), you will need to add a new PP resource for the SSO server and configure the login form on that resource instead of the original application resource. One side benefit of this additional resource is that it can reused for other applications relying on the same SSO server for login. After entering the login page URL (make sure dropdown says "URL"), click "Automatically Detect Form Fields". This will bring up the web app's login page in a new browser window. Fill it out and submit it as you would normally. If everything goes right, Pagelet Producer will intercept the submitted values and fill out all the needed configuration data in the Admin UI. If the login form window doesn't close or configuration data doesn't get filled in, you may have not entered the login page URL correctly. Review the two cautionary notes above and make any necessary changes. If the form fields got filled automatically, it's time to save the configuration and test it out. If you can access a protected area of the backend application via a proxied PP URL without filling out its login form, then you are pretty much done with login form configuration. The only other step you will need to complete before declaring this aspect of configuration production ready is configuring form field source. You may skip to that section below. Manual Login Form Identification Let's take a closer look at Login Form Identification. This determines how Pagelet Producer recognizes login forms as such. URL The most efficient way of detecting login forms is by looking at the page URL. This method can only be used under the following conditions: Login page URL must be different from the post login application URLs. Login page URL must stay constant regardless of the path it takes to reach the page. For example, reaching the login page by going to the application base URL or to a specific protected URL must result in a redirect to the same login page URL (query string excluded). If only the query string parameters change, just leave out the query string from the configured login page URL. If either of these conditions is not fullfilled, you must switch to the RegEx approach below. RegEx If the login page URL is not uniform enough across all scenarios or is indistinguishable from other page locations, PP can be configured to recognize it by looking at the page markup itself. This is accomplished by changing the dropdown to "RegEx". If regular expressions scare you, take comfort from the fact that in most cases you won't need to enter any special regex characters. Let's look at an example: Say you have a login form that looks like <form id='loginForm' action='login?from=pageA' > <input id='user'> <input id='pass'> </form> Since this form has an id attribute, you can be reasonably sure that this login form can be uniquely identified across the web application by this snippet: "id='loginForm'". (Unless, of course your backend web application contains login forms to other apps). Since no wildcards are needed to find this snippet, you can just enter it as is into the RegEx field - no special regular expression characters needed! If the web developer who created the form wasn't kind enough to provide a unique id, you will need to look for other snippets of the page to uniquely identify it. It could be the action URL, an input field id, or some other markup fragment. You should abstain from using UI text as an identifier it may change in translated versions of the page and prevent the login page logic from working for international users. You may need to turn to regular expression wildcard syntax if no simple matches work. For more information on regular expression, refer to the Resources section. Form Submit Location Now we'll look at the form submit location. If the captured URL contains query string parameters that will likely change from one form submission to the next, you will need to change its type to RegEx. This type will tell Pagelet Producer to parse the login page for the action URL and submit to the value found. The regular expression needs to point at the actual action URL with its first grouping expression. Taking the example form definition above, the form submit location regex would be: action='(.*?)' The parentheses are used to identify the actual action URL, while the rest of the expression provides the context for finding it. Expression .*? is a so-called reluctant wildcard that matches any character excluding the single quote that follows. See Resources section below for further information on regular expressions. Manual Form Field Detection If the Admin UI form field detection wizard fails to populate login form configuration page, you will have to enter the fields by hand. Use a built-in browser developer tool or addon (e.g. Firebug) to inspect the form element and its children input elements. For each input element (including hidden elements), create an entry under Form Fields. Change its Source according to the next section. Form Field Source Change the source of any of the fields not exposed to the users of the login form (i.e. hidden fields) to "Generated". This means Pagelet Producer will just use the values returned by the web app rather than supplying values it stored. For fields that contain sensitive data or vary from user to user (e.g. username & password), change the source to User (Credential) Vault. Logging Support To help you troubleshoot you autologin configuration, PP provides some useful logging support. To turn on detailed logging for the autologin feature, navigate to Settings in Admin UI. Under Logging, change the log level for AutoLogin to Finest. Known Limitations Autologin feature may not work as expected if login form fields (not just the values, but the DOM elements themselves) are generated dynamically by client side JavaScript. Resources RegEx RegEx Reference from Java RegEx Test Tool

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• How to avoid the Portlet Skin mismatch

  - by Martin Deh

  here are probably many on going debates whether to use portlets or taskflows in a WebCenter custom portal application.  Usually the main battle on which side to take in these debates are centered around which technology enables better performance.  The good news is that both of my colleagues, Maiko Rocha and George Maggessy have posted their respective views on this topic so I will not have to further the discussion.  However, if you do plan to use portlets in a WebCenter custom portal application, this post will help you not have the "portlet skin mismatch" issue.   An example of the presence of the mismatch can be view from the applications log: The skin customsharedskin.desktop specified on the requestMap will be used even though the consumer's skin's styleSheetDocumentId on the requestMap does not match the local skin's styleSheetDocument's id. This will impact performance since the consumer and producer stylesheets cannot be shared. The producer styleclasses will not be compressed to avoid conflicts. A reason the ids do not match may be the jars are not identical on the producer and the consumer. For example, one might have trinidad-skins.xml's skin-additions in a jar file on the class path that the other does not have. Notice that due to the mismatch the portlet's CSS will not be able to be compressed, which will most like impact performance in the portlet's consuming portal. The first part of the blog will define the portlet mismatch and cover some debugging tips that can help you solve the portlet mismatch issue.  Following that I will give a complete example of the creating, using and sharing a shared skin in both a portlet producer and the consumer application. Portlet Mismatch Defined  In general, when you consume/render an ADF page (or task flow) using the ADF Portlet bridge, the portlet (producer) would try to use the skin of the consumer page - this is called skin-sharing. When the producer cannot match the consumer skin, the portlet would generate its own stylesheet and reference it from its markup - this is called mismatched-skin. This can happen because: The consumer and producer use different versions of ADF Faces, or The consumer has additional skin-additions that the producer doesn't have or vice-versa, or The producer does not have the consumer skin For case (1) & (2) above, the producer still uses the consumer skin ID to render its markup. For case (3), the producer would default to using portlet skin. If there is a skin mis-match then there may be a performance hit because: The browser needs to fetch this extra stylesheet (though it should be cached unless expires caching is turned off) The generated portlet markup uses uncompressed styles resulting in a larger markup It is often not obvious when a skin mismatch occurs, unless you look for either of these indicators: The log messages in the producer log, for example: The skin blafplus-rich.desktop specified on the requestMap will not be used because the styleSheetDocument id on the requestMap does not match the local skin's styleSheetDocument's id. It could mean the jars are not identical. For example, one might have trinidad-skins.xml's skin-additions in a jar file on the class path that the other does not have. View the portlet markup inside the iframe, there should be a <link> tag to the portlet stylesheet resource like this (note the CSS is proxied through consumer's resourceproxy): <link rel=\"stylesheet\" charset=\"UTF-8\" type=\"text/css\" href=\"http:.../resourceproxy/portletId...252525252Fadf%252525252Fstyles%252525252Fcache%252525252Fblafplus-rich-portlet-d1062g-en-ltr-gecko.css... Using HTTP monitoring tool (eg, firebug, httpwatch), you can see a request is made to the portlet stylesheet resource (see URL above) There are a number of reasons for mismatched-skin. For skin to match the producer and consumer must match the following configurations: The ADF Faces version (different versions may have different style selectors) Style Compression, this is defined in the web.xml (default value is false, i.e. compression is ON) Tonal styles or themes, also defined in the web.xml via context-params The same skin additions (jars with skin) are available for both producer and consumer.  Skin additions are defined in the trinidad-skins.xml, using the <skin-addition> tags. These are then aggregated from all the jar files in the classpath. If there's any jar that exists on the producer but not the consumer, or vice veras, you get a mismatch. Debugging Tips  Ensure the style compression and tonal styles/themes match on the consumer and producer, by looking at the web.xml documents for the consumer & producer applications It is bit more involved to determine if the jars match.  However, you can enable the Trinidad logging to show which skin-addition it is processing.  To enable this feature, update the logging.xml log level of both the producer and consumer WLS to FINEST.  For example, in the case of the WebLogic server used by JDeveloper: $JDEV_USER_DIR/system<version number>/DefaultDomain/config/fmwconfig/servers/DefaultServer/logging.xml Add a new entry: <logger name="org.apache.myfaces.trinidadinternal.skin.SkinUtils" level="FINEST"/> Restart WebLogic.  Run the consumer page, you should see the following logging in both the consumer and producer log files. Any entries that don't match is the cause of the mismatch.  The following is an example of what the log will produce with this setting: [SRC_CLASS: org.apache.myfaces.trinidadinternal.skin.SkinUtils] [APP: WebCenter] [SRC_METHOD: _getMetaInfSkinsNodeList] Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/announcement-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/calendar-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/custComps-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/forum-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/page-service-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/peopleconnections-kudos-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/peopleconnections-wall-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/portlet-client-adf-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/rtc-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/serviceframework-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/smarttag-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.skin/in1ar8/APP-INF/lib/spaces-service-skins.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/oracle.webcenter.composer/3yo7j/WEB-INF/lib/custComps-skin.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/adf.oracle.domain.webapp/q433f9/WEB-INF/lib/adf-richclient-impl-11.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/adf.oracle.domain.webapp/q433f9/WEB-INF/lib/dvt-faces.jar!/META-INF/trinidad-skins.xml Processing skin URL:zip:/tmp/_WL_user/adf.oracle.domain.webapp/q433f9/WEB-INF/lib/dvt-trinidad.jar!/META-INF/trinidad-skins.xml   The Complete Example The first step is to create the shared library.  The WebCenter documentation covering this is located here in section 15.7.  In addition, our ADF guru Frank Nimphius also covers this in hes blog.  Here are my steps (in JDeveloper) to create the skin that will be used as the shared library for both the portlet producer and consumer. Create a new Generic Application Give application name (i.e. MySharedSkin) Give a project name (i.e. MySkinProject) Leave Project Technologies blank (none selected), and click Finish Create the trinidad-skins.xml Right-click on the MySkinProject node in the Application Navigator and select "New" In the New Galley, click on "General", select "File" from the Items, and click OK In the Create File dialog, name the file trinidad-skins.xml, and (IMPORTANT) give the directory path to MySkinProject\src\META-INF In the trinidad-skins.xml, complete the skin entry.  for example: <?xml version="1.0" encoding="windows-1252" ?> <skins xmlns="http://myfaces.apache.org/trinidad/skin">   <skin>     <id>mysharedskin.desktop</id>     <family>mysharedskin</family>     <extends>fusionFx-v1.desktop</extends>     <style-sheet-name>css/mysharedskin.css</style-sheet-name>   </skin> </skins> Create CSS file In the Application Navigator, right click on the META-INF folder (where the trinidad-skins.xml is located), and select "New" In the New Gallery, select Web-Tier-> HTML, CSS File from the the Items and click OK In the Create Cascading Style Sheet dialog, give the name (i.e. mysharedskin.css) Ensure that the Directory path is the under the META-INF (i.e. MySkinProject\src\META-INF\css) Once the new CSS opens in the editor, add in a style selector.  For example, this selector will style the background of a particular panelGroupLayout: af|panelGroupLayout.customPGL{     background-color:Fuchsia; } Create the MANIFEST.MF (used for deployment JAR) In the Application Navigator, right click on the META-INF folder (where the trinidad-skins.xml is located), and select "New" In the New Galley, click on "General", select "File" from the Items, and click OK In the Create File dialog, name the file MANIFEST.MF, and (IMPORTANT) ensure that the directory path is to MySkinProject\src\META-INF Complete the MANIFEST.MF, where the extension name is the shared library name Manifest-Version: 1.1 Created-By: Martin Deh Implementation-Title: mysharedskin Extension-Name: mysharedskin.lib.def Specification-Version: 1.0.1 Implementation-Version: 1.0.1 Implementation-Vendor: MartinDeh Create new Deployment Profile Right click on the MySkinProject node, and select New From the New Gallery, select General->Deployment Profiles, Shared Library JAR File from Items, and click OK In the Create Deployment Profile dialog, give name (i.e.mysharedskinlib) and click OK In the Edit JAR Deployment dialog, un-check Include Manifest File option  Select Project Output->Contributors, and check Project Source Path Select Project Output->Filters, ensure that all items under the META-INF folder are selected Click OK to exit the Project Properties dialog Deploy the shared lib to WebLogic (start server before steps) Right click on MySkin Project and select Deploy For this example, I will deploy to JDeverloper WLS In the Deploy dialog, select Deploy to Weblogic Application Server and click Next Choose IntegratedWebLogicServer and click Next Select Deploy to selected instances in the domain radio, select Default Server (note: server must be already started), and ensure Deploy as a shared Library radio is selected Click Finish Open the WebLogic console to see the deployed shared library The following are the steps to create a simple test Portlet Create a new WebCenter Portal - Portlet Producer Application In the Create Portlet Producer dialog, select default settings and click Finish Right click on the Portlets node and select New IIn the New Gallery, select Web-Tier->Portlets, Standards-based Java Portlet (JSR 286) and click OK In the General Portlet information dialog, give portlet name (i.e. MyPortlet) and click Next 2 times, stopping at Step 3 In the Content Types, select the "view" node, in the Implementation Method, select the Generate ADF-Faces JSPX radio and click Finish Once the portlet code is generated, open the view.jspx in the source editor Based on the simple CSS entry, which sets the background color of a panelGroupLayout, replace the <af:form/> tag with the example code <af:form>         <af:panelGroupLayout id="pgl1" styleClass="customPGL">           <af:outputText value="background from shared lib skin" id="ot1"/>         </af:panelGroupLayout>  </af:form> Since this portlet is to use the shared library skin, in the generated trinidad-config.xml, remove both the skin-family tag and the skin-version tag In the Application Resources view, under Descriptors->META-INF, double-click to open the weblogic-application.xml Add a library reference to the shared skin library (note: the library-name must match the extension-name declared in the MANIFEST.MF):  <library-ref>     <library-name>mysharedskin.lib.def</library-name>  </library-ref> Notice that a reference to oracle.webcenter.skin exists.  This is important if this portlet is going to be consumed by a WebCenter Portal application.  If this tag is not present, the portlet skin mismatch will happen.  Configure the portlet for deployment Create Portlet deployment WAR Right click on the Portlets node and select New In the New Gallery, select Deployment Profiles, WAR file from Items and click OK In the Create Deployment Profile dialog, give name (i.e. myportletwar), click OK Keep all of the defaults, however, remember the Context Root entry (i.e. MyPortlet4SharedLib-Portlets-context-root, this will be needed to obtain the producer WSDL URL) Click OK, then OK again to exit from the Properties dialog Since the weblogic-application.xml has to be included in the deployment, the portlet must be deployed as a WAR, within an EAR In the Application dropdown, select Deploy->New Deployment Profile... By default EAR File has been selected, click OK Give Deployment Profile (EAR) a name (i.e. MyPortletProducer) and click OK In the Properties dialog, select Application Assembly and ensure that the myportletwar is checked Keep all of the other defaults and click OK For this demo, un-check the Auto Generate ..., and all of the Security Deployment Options, click OK Save All In the Application dropdown, select Deploy->MyPortletProducer In the Deployment Action, select Deploy to Application Server, click Next Choose IntegratedWebLogicServer and click Next Select Deploy to selected instances in the domain radio, select Default Server (note: server must be already started), and ensure Deploy as a standalone Application radio is selected The select deployment type (identifying the deployment as a JSR 286 portlet) dialog appears.  Keep default radio "Yes" selection and click OK Open the WebLogic console to see the deployed Portlet The last step is to create the test portlet consuming application.  This will be done using the OOTB WebCenter Portal - Framework Application.  Create the Portlet Producer Connection In the JDeveloper Deployment log, copy the URL of the portlet deployment (i.e. http://localhost:7101/MyPortlet4SharedLib-Portlets-context-root Open a browser and paste in the URL.  The Portlet information page should appear.  Click on the WSRP v2 WSDL link Copy the URL from the browser (i.e. http://localhost:7101/MyPortlet4SharedLib-Portlets-context-root/portlets/wsrp2?WSDL) In the Application Resources view, right click on the Connections folder and select New Connection->WSRP Connection Give the producer a name or accept the default, click Next Enter (paste in) the WSDL URL, click Next If connection to Portlet is succesful, Step 3 (Specify Additional ...) should appear.  Accept defaults and click Finish Add the portlet to a test page Open the home.jspx.  Note in the visual editor, the orange dashed border, which identifies the panelCustomizable tag. From the Application Resources. select the MyPortlet portlet node, and drag and drop the node into the panelCustomizable section.  A Confirm Portlet Type dialog appears, keep default ADF Rich Portlet and click OK Configure the portlet to use the shared skin library Open the weblogic-application.xml and add the library-ref entry (mysharedskin.lib.def) for the shared skin library.  See create portlet example above for the steps Since by default, the custom portal using a managed bean to (dynamically) determine the skin family, the default trinidad-config.xml will need to be altered Open the trinidad-config.xml in the editor and replace the EL (preferenceBean) for the skin-family tag, with mysharedskin (this is the skin-family named defined in the trinidad-skins.xml) Remove the skin-version tag Right click on the index.html to test the application   Notice that the JDeveloper log view does not have any reporting of a skin mismatch.  In addition, since I have configured the extra logging outlined in debugging section above, I can see the processed skin jar in both the producer and consumer logs: <SkinUtils> <_getMetaInfSkinsNodeList> Processing skin URL:zip:/JDeveloper/system11.1.1.6.38.61.92/DefaultDomain/servers/DefaultServer/upload/mysharedskin.lib.def/[email protected]/app/mysharedskinlib.jar!/META-INF/trinidad-skins.xml 

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• Zeta Producer Command Routing

  Introducing a small UI command routing (event bubbling) library for Windows Forms .NET

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• Is LinkedBlockingQueue a correct choice for a producer-consumer like scenario?

  - by sunnyj

  I have a producer-consumer like scenario. Class A produces objects of type E. I have to hold it in a static data structure in class A, because the consumer logic should be handled in a class B, which has no reference to object of A. Is LinkedBlockingQueue the correct data type for the queue? Or are there any better selection for this?

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• Producer consumer with qualifications

  - by tgguy

  I am new to clojure and am trying to understand how to properly use its concurrency features, so any critique/suggestions is appreciated. So I am trying to write a small test program in clojure that works as follows: there 5 producers and 2 consumers a producer waits for a random time and then pushes a number onto a shared queue. a consumer should pull a number off the queue as soon as the queue is nonempty and then sleep for a short time to simulate doing work the consumers should block when the queue is empty producers should block when the queue has more than 4 items in it to prevent it from growing huge Here is my plan for each step above: the producers and consumers will be agents that don't really care for their state (just nil values or something); i just use the agents to send-off a "consumer" or "producer" function to do at some time. Then the shared queue will be (def queue (ref [])). Perhaps this should be an atom though? in the "producer" agent function, simply (Thread/sleep (rand-int 1000)) and then (dosync (alter queue conj (rand-int 100))) to push onto the queue. I am thinking to make the consumer agents watch the queue for changes with add-watcher. Not sure about this though..it will wake up the consumers on any change, even if the change came from a consumer pulling something off (possibly making it empty) . Perhaps checking for this in the watcher function is sufficient. Another problem I see is that if all consumers are busy, then what happens when a producer adds something new to the queue? Does the watched event get queued up on some consumer agent or does it disappear? see above I really don't know how to do this. I heard that clojure's seque may be useful, but I couldn't find enough doc on how to use it and my initial testing didn't seem to work (sorry don't have the code on me anymore)

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• How solve consumer/producer task using semaphores

  - by user1074896

  I have SimpleProducerConsumer class that illustrate consumer/producer problem (I am not sure that it's correct). public class SimpleProducerConsumer { private Stack<Object> stack = new Stack<Object>(); private static final int STACK_MAX_SIZE = 10; public static void main(String[] args) { SimpleProducerConsumer pc = new SimpleProducerConsumer(); new Thread(pc.new Producer(), "p1").start(); new Thread(pc.new Producer(), "p2").start(); new Thread(pc.new Consumer(), "c1").start(); new Thread(pc.new Consumer(), "c2").start(); new Thread(pc.new Consumer(), "c3").start(); } public synchronized void push(Object d) { while (stack.size() >= STACK_MAX_SIZE) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } stack.push(new Object()); System.out.println("push " + Thread.currentThread().getName() + " " + stack.size()); notify(); } public synchronized Object pop() { while (stack.size() == 0) try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } try { Thread.sleep(50); } catch (InterruptedException e) { e.printStackTrace(); } stack.pop(); System.out.println("pop " + Thread.currentThread().getName() + " " + stack.size()); notify(); return null; } class Consumer implements Runnable { @Override public void run() { while (true) { pop(); } } } class Producer implements Runnable { @Override public void run() { while (true) { push(new Object()); } } } } I found simple realization of semaphore(here:http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html I know that there is concurrency package) How I need to change code to exchange java objects monitors to my custom semaphore. (To illustrate C/P problem using semaphores) Semaphore: class Semaphore { private int counter; public Semaphore() { this(0); } public Semaphore(int i) { if (i < 0) throw new IllegalArgumentException(i + " < 0"); counter = i; } public synchronized void release() { if (counter == 0) { notify(); } counter++; } public synchronized void acquire() throws InterruptedException { while (counter == 0) { wait(); } counter--; } }

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• Producer/consumer system using database (MySql), is this feasible?

  - by johnrl

  Hi all. I need to use something to coordinate my system with several consumers/producers each running on different machines with different operating systems. I have been researching on using MySql to do this, but it seems ridiculously difficult. My requirements are simple: I want to be able to add or remove consumers/producers at any time and thus they should not depend on each other at all. Naturally a database would separate the two nicely. I have been looking at Q4M message queuing plugin for MySql but it seems complicated to use: I have to recompile it every time I upgrade MySql (can this really be true?) because when I try to install it on Ubuntu 9.10 with MySql 5.1.37 it says "Can't open shared library 'libqueue_engine.so' (errno: 0 API version for STORAGE ENGINE plugin is too different)". There is no precompiled version for MySql 5.1.37 apparently. Also what if I want to run MySql on my windows machine, then I can't rely on this plugin as it only seems to run on Linux and OSX?? I really need some input on how to construct my system best possible.

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• Producer Consumer Issue with Core Data

  - by Mugunth Kumar

  I've a Core Data application. In the producer thread, I pull data from a web service and store it in my object and call save. My consumer object is a table view controller that displays the same. However, the app crashes and I get NSFetchedResultsController Error: expected to find object (entity: FeedEntry; id: 0xf46f40 ; data: ) in section (null) for deletion on the console. When I debug it, everything works fine. So I understood that it's like a race issue. How is these kind of problem solved? What's the best way to design a producer-consumer app with core-data?

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• Optimizing a shared buffer in a producer/consumer multithreaded environment

  - by Etan

  I have some project where I have a single producer thread which writes events into a buffer, and an additional single consumer thread which takes events from the buffer. My goal is to optimize this thing for a single machine to achieve maximum throughput. Currently, I am using some simple lock-free ring buffer (lock-free is possible since I have only one consumer and one producer thread and therefore the pointers are only updated by a single thread). #define BUF_SIZE 32768 struct buf_t { volatile int writepos; volatile void * buffer[BUF_SIZE]; volatile int readpos;) }; void produce (buf_t *b, void * e) { int next = (b->writepos+1) % BUF_SIZE; while (b->readpos == next); // queue is full. wait b->buffer[b->writepos] = e; b->writepos = next; } void * consume (buf_t *b) { while (b->readpos == b->writepos); // nothing to consume. wait int next = (b->readpos+1) % BUF_SIZE; void * res = b->buffer[b->readpos]; b->readpos = next; return res; } buf_t *alloc () { buf_t *b = (buf_t *)malloc(sizeof(buf_t)); b->writepos = 0; b->readpos = 0; return b; } However, this implementation is not yet fast enough and should be optimized further. I've tried with different BUF_SIZE values and got some speed-up. Additionaly, I've moved writepos before the buffer and readpos after the buffer to ensure that both variables are on different cache lines which resulted also in some speed. What I need is a speedup of about 400 %. Do you have any ideas how I could achieve this using things like padding etc?

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