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Search found 190 results on 8 pages for 'producer'.

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  • Check if an object is facing another based on angles

    - by Isaiah
    I already have something that calculates the bearing angle to get one object to face another. You give it the positions and it returns the angle to get one to face the other. Now I need to figure out how tell if on object is facing toward another object within a specified field and I can't find any information about how to do this. The objects are obj1 and obj2. Their angles are at obj1.angle and obj2.angle. Their vectors are at obj1.pos and obj2.pos. It's in the format [x,y]. The angle to have one face directly at another is found with direction(obj1.pos,obj2.pos). I want to set the function up like this: isfacing(obj1,obj2,area){...} and return true/false depending if it's in the specified field area to the angle to directly see it. I've got a base like this: var isfacing = function (obj1,obj2,area){ var toface = direction(obj1.pos,obj2.pos); if(toface+area >= obj1.angle && ob1.angle >= toface-area){ return true; } return false; } But my problem is that the angles are in 360 degrees, never above 360 and never below 0. How can I account for that in this? If the first object's angle is say at 0 and say I subtract a field area of 20 or so. It'll check if it's less than -20! If I fix the -20 it becomes 340 but x < 340 isn't what I want, I'd have to x 340 in that case. Is there someone out there with more sleep than I that can help a new dev pulling an all-nighter just to get enemies to know if they're attacking in the right direction? I hope I'm making this harder than it seems. I'd just make them always face the main char if the producer didn't want attacks from behind to work while blocking. In which case I'll need the function above anyways. I've tried to give as much info as I can think would help. Also this is in 2d.

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  • Asynchronously returning a hierarchal data using .NET TPL... what should my return object "look" like?

    - by makerofthings7
    I want to use the .NET TPL to asynchronously do a DIR /S and search each subdirectory on a hard drive, and want to search for a word in each file... what should my API look like? In this scenario I know that each sub directory will have 0..10000 files or 0...10000 directories. I know the tree is unbalanced and want to return data (in relation to its position in the hierarchy) as soon as it's available. I am interested in getting data as quickly as possible, but also want to update that result if "better" data is found (better means closer to the root of c:) I may also be interested in finding all matches in relation to its position in the hierarchy. (akin to a report) Question: How should I return data to my caller? My first guess is that I think I need a shared object that will maintain the current "status" of the traversal (started | notstarted | complete ) , and might base it on the System.Collections.Concurrent. Another idea that I'm considering is the consumer/producer pattern (which ConcurrentCollections can handle) however I'm not sure what the objects "look" like. Optional Logical Constraint: The API doesn't have to address this, but in my "real world" design, if a directory has files, then only one file will ever contain the word I'm looking for.  If someone were to literally do a DIR /S as described above then they would need to account for more than one matching file per subdirectory. More information : I'm using Azure Tables to store a hierarchy of data using these TPL extension methods. A "node" is a table. Not only does each node in the hierarchy have a relation to any number of nodes, but it's possible for each node to have a reciprocal link back to any other node. This may have issues with recursion but I'm addressing that with a shared object in my recursion loop. Note that each "node" also has the ability to store local data unique to that node. It is this information that I'm searching for. In other words, I'm searching for a specific fixed RowKey in a hierarchy of nodes. When I search for the fixed RowKey in the hierarchy I'm interested in getting the results FAST (first node found) but prefer data that is "closer" to the starting point of the hierarchy. Since many nodes may have the particular RowKey I'm interested in, sometimes I may want to get a report of ALL the nodes that contain this RowKey.

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  • Portable USB drives hidden pertition - New request

    - by ZXC
    This question was made by Francesco on Jul 29 '11 at 17:14. and the replies were not satisfactory due they not point to an important problem that´s: Why could anyone want to make certain data only accesible for a program but not to the users?. For example: If I want to do a safe distribution of original music for demostration purposes I will need several requisites: 1) The music should be heard using a simple procedure like selecting the name of each song on a playlist of a mediaplayer. 2) The portable media, ussually a portable USB drive, must hide for complete and should make unaccesible the files that contain the audio data to anything but the mediaplayer, that must be in the first partition, the one that is visible. 3) Considering that´s impossible to really hide files in a non-hidden partition, a second hidden partition should be created in the USB drive and the audio data will be stored there. 4) The trick is to read the audio data files stored in the hidden partition with a mediaplayer stored in the visible partition, the media player also should be a complete standalone program and independent from any library of the operating system except of the OS audio system. 5) The hidden partition should have a copy protection scheme that could impede to do copies of the data or create working ISO images of it. I know that this description could not be technically accurate but it has a complete logic from the needs of a music producer against the problem of piracy. The philosophy that surrounds the concept is to transform a virtual object like a digital string of audio in a solid object like the analog vinyl discs are.

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  • RabbitMQ message consumers stop consuming messages

    - by Bruno Thomas
    Hi server fault, Our team is in a spike sprint to choose between ActiveMQ or RabbitMQ. We made 2 little producer/consumer spikes sending an object message with an array of 16 strings, a timestamp, and 2 integers. The spikes are ok on our devs machines (messages are well consumed). Then came the benchs. We first noticed that somtimes, on our machines, when we were sending a lot of messages the consumer was sometimes hanging. It was there, but the messsages were accumulating in the queue. When we went on the bench plateform : cluster of 2 rabbitmq machines 4 cores/3.2Ghz, 4Gb RAM, load balanced by a VIP one to 6 consumers running on the rabbitmq machines, saving the messages in a mysql DB (same type of machine for the DB) 12 producers running on 12 AS machines (tomcat), attacked with jmeter running on another machine. The load is about 600 to 700 http request per second, on the servlets that produces the same load of RabbitMQ messages. We noticed that sometimes, consumers hang (well, they are not blocked, but they dont consume messages anymore). We can see that because each consumer save around 100 msg/sec in database, so when one is stopping consumming, the overall messages saved per seconds in DB fall down with the same ratio (if let say 3 consumers stop, we fall around 600 msg/sec to 300 msg/sec). During that time, the producers are ok, and still produce at the jmeter rate (around 600 msg/sec). The messages are in the queues and taken by the consumers still "alive". We load all the servlets with the producers first, then launch all the consumers one by one, checking if the connexions are ok, then run jmeter. We are sending messages to one direct exchange. All consumers are listening to one persistent queue bounded to the exchange. That point is major for our choice. Have you seen this with rabbitmq, do you have an idea of what is going on ? Thank you for your answers.

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  • Bluescreen Stop 0x00000027 RDR_FILE_SYSTEM after cloning system on new HDD

    - by Daniel
    A couple of months ago I got a new 500GB HDD for my no-name-brand Laptop PC and I cloned the complete Win 7 Pro 32bit system with clonezilla from the old 70GB drive to the new one. At first everything was great, the new driver was immediately updated. But since then I get on a more and more frequent level (used to be every 2-3 days, but now it's more like 2-3 times a day) a BSOD Stop error. From the eventlog in Windows I know that there are two different error codes sppoking aroung: 0x00000027 (0xbaad0073, 0x9954f80c, 0x9954f3f0, 0x8ecd7c82) RDR_FILE_SYSTEM 0x00000044 (0x85443230, 0x00000eae, 0x00000000, 0x00000000) MULTIPLE_IRP_COMPLETE_REQUESTS I checked for viruses and did a complete HDD check using the Windows tool and WesternDigital tool (which is the producer of the new HDD) without results. I also looked for driver updates but couldn't find any. The name of the HDD as shown in the device manager is: WDC WD5000BPVT-00HXZT1 ATA Device. I'm really a noob regarding those kind of problems, so if you have any idea what I can try without losing all my data, let me know. Also, if any additional information are required.

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  • How to debug modsecurity_audit_log

    - by max87
    I was accessing www.example.com/RestAPI/index.php/tweets.json in my server. The modsec_audit.log showed the following error, but there is no related errors/warnings in modsec_debug.log. I could see the Internal Server error is logged in example-error_log. How can I debug this Internal Server error? --8560e90b-A-- [21/Mar/2012:07:01:52 +0000] T2l84H8AAAEAAGxPZ@QAAAAG x.x.x.x 33101 x.x.x.x 80 --8560e90b-B-- GET /RestAPI/index.php/tweets.json HTTP/1.1 Host: www.example.com User-Agent: Mozilla/5.0 (X11; Linux i686; rv:11.0) Gecko/20100101 Firefox/11.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8 Accept-Language: en-us,en;q=0.5 Accept-Encoding: gzip, deflate DNT: 1 Cookie: __utma=159129855.1463065063.1331789485.1331789485.1331789485.1; __utmz=159129855.1331789485.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); 8cb6a414cf5ec1919864de0e80bea4da=0es7dcu0p10cocfpferb2lddi0; 8926e4f3c475bb6fcacb409299f1bd27=53cf8c5e6bf78ea45096945377e6d609 Connection: keep-alive Cache-Control: max-age=0 --8560e90b-F-- HTTP/1.0 500 Internal Server Error X-Powered-By: PHP/5.3.5 Content-Length: 0 Connection: close Content-Type: text/html; charset=UTF-8 --8560e90b-H-- Apache-Handler: php5-script Stopwatch: 1332313312358005 130428 (- - -) Producer: ModSecurity for Apache/2.5.12 (http://www.modsecurity.org/); core ruleset/2.0.5. Server: Apache --8560e90b-Z--

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  • OTN ArchBeat Top 10 for September 2012

    - by Bob Rhubart
    The results are in... Listed below are the Top 10 most popular items shared via the OTN ArchBeat Facebook Page for the month of September 2012. The Real Architects of Los Angeles - OTN Architect Day - Oct 25 No gossip. No drama. No hair pulling. Just a full day of technical sessions and peer interaction focused on using Oracle technologies in today's cloud and SOA architectures. The event is free, but seating is limited, so register now. Thursday October 25, 2012. 8:00 a.m. – 5:00 p.m. Sofitel Los Angeles, 8555 Beverly Boulevard, Los Angeles, CA 90048. Oracle Fusion Middleware Security: Attaching OWSM policies to JRF-based web services clients "OWSM (Oracle Web Services Manager) is Oracle's recommended method for securing SOAP web services," says Oracle Fusion Middleware A-Team member Andre Correa. "It provides agents that encapsulate the necessary logic to interact with the underlying software stack on both service and client sides. Such agents have their behavior driven by policies. OWSM ships with a bunch of policies that are adequate to most common real world scenarios." His detailed post shows how to make it happen. Oracle 11gR2 RAC on Software Defined Network (SDN) (OpenvSwitch, Floodlight, Beacon) | Gilbert Stan "The SDN [software defined network] idea is to separate the control plane and the data plane in networking and to virtualize networking the same way we have virtualized servers," explains Gil Standen. "This is an idea whose time has come because VMs and vmotion have created all kinds of problems with how to tell networking equipment that a VM has moved and to preserve connectivity to VPN end points, preserve IP, etc." H/T to Oracle ACE Director Tim Hall for the recommendation. Process Oracle OER Events using a simple Web Service | Bob Webster Bob Webster's post "provides an example of a simple web service that processes Oracle Enterprise Repository (OER) Events. The service receives events from OER and utilizes the OER REX API to implement simple OER automations for selected event types." Understanding Oracle BI 11g Security vs Legacy Oracle BI 10g | Christian Screen "After conducting a large amount of Oracle BI 10g to Oracle BI 11g upgrades and after writing the Oracle BI 11g book,"says Oracle ACE Christian Screen, "I still continually get asked one of the most basic questions regarding security in Oracle BI 11g; How does it compare to Oracle BI 10g? The trail of questions typically goes on to what are the differences? And, how do we leverage our current Oracle BI 10g security table schema in Oracle BI 11g?" OIM-OAM-OAAM integration using TAP – Request Flow you must understand!! | Atul Kumar Atul Kumar's post addresses "key points and request flow that you must understand" when integrating three Oracle Identity Management product Oracle Identity Management, Oracle Access Management, and Oracle Adaptive Access Manager. Adding a runtime LOV for a taskflow parameter in WebCenter | Yannick Ongena Oracle ACE Yannick Ongena illustrates how to customize the parameters tab for a taskflow in WebCenter. Tips on Migrating from AquaLogic .NET Accelerator to WebCenter WSRP Producer for .NET | Scott Nelson "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," says Scott Nelson. "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." 15 Lessons from 15 Years as a Software Architect | Ingo Rammer In this presentation from the GOTO Conference in Copenhagen, Ingo Rammer shares 15 tips regarding people, complexity and technology that he learned doing software architecture for 15 years. WebCenter Content (WCC) Trace Sections | ECM Architect ECM Architect Kevin Smith shares a detailed technical post covering WebCenter Content (WCC) Trace Sections. Thought for the Day "Eventually everything connects - people, ideas, objects. The quality of the connections is the key to quality per se." — Charles Eames (June 17, 1907 – August 21, 1978) Source: SoftwareQuotes.com

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  • ArchBeat Link-o-Rama Top 10 for September 2-8, 2012

    - by Bob Rhubart
    The Top 10 items shared on the OTN Facebook Page for the week of September 2-8, 2012. Adding a runtime LOV for a taskflow parameter in WebCenter | Yannick Ongena Oracle ACE Yannick Ongena illustrates how to customize the parameters tab for a taskflow in WebCenter. Tips on Migrating from AquaLogic .NET Accelerator to WebCenter WSRP Producer for .NET | Scott Nelson "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," says Scott Nelson. "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." Free Event: Oracle Technology Network Architect Day – Boston, MA – 9/12/2012 Sure, you could ask a voodoo priestess for help in improving your solution architecture skills. But there's the whole snake thing, and the zombie thing, and other complications. So why not keep it simple and register for Oracle Technology Network Architect Day in Boston, MA. There's no magic, just a full day of technical sessions covering Cloud, SOA, Engineered Systems, and more. Registration is free, but seating is limited. You'll curse yourself if you miss this one. Starting and Stopping Fusion Applications the Right Way | Ronaldo Viscuso While the fastartstop tool that ships with Oracle Fusion Applications does most of the work to start/stop/bounce the Fusion Apps environment, it does not do it all. Oracle Fusion Applications A-Team blogger Ronaldo Viscuso's post "aims to explain all tasks involved in starting and stopping a Fusion Apps environment completely." Article Index: Architect Community Column in Oracle Magazine Did you know that Oracle Magazine features a regular column devoted specifically to the architect community? Every issue includes insight and expertise from architects who regularly work with Oracle Technologies. Click here to see a complete list of these articles. Using FMAP and AnalyticsRes in a Oracle BI High Availability Implementation | Art of Business Intelligence "The fmap syntax has been used for a long time in Oracle BI / Siebel Analytics when referencing images inherent in the application as well as custom images," says Oracle ACE Christian Screen. "This syntax is used on Analysis requests an dashboards." Dodeca Customer Feedback - The Rosewood Company | Tim Tow Oracle ACE Director Tim Tow shares anecdotal comments from one of his clients, a company that is deploying Dodeca to replace an aging VBA/Essbase application. Configuring UCM cache to check for external Content Server changes | Martin Deh Oracle WebCenter and ADF A-Team blogger shares the background information and the solution to a recently encountered customer scenario. Attend OTN Architect Day in Los Angeles – by Architects, for Architects – October 25 The OTN Architect Day roadshow stops in Boston next week, then it's on to Los Angeles for another all architecture, all day event on Thursday October 25, 2012 at the Sofitel Los Angeles, 555 Beverly Boulevard, Los Angeles, CA 90048. Like all Architect Day events, this one is absolutley free, so register now. The Role of Oracle VM Server for SPARC In a Virtualization Strategy New OTN article from Matthias Pfutzner. Thought for the Day "Practicing architects, through eduction, experience and examples, accumulate a considerable body of contextual sense by the time they're entrusted with solving a system-level problem…" — Eberhardt Rechtin (January 16, 1926 – April 14, 2006) Source: SoftwareQuotes.com

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  • Missing Edit Option on Silverlight 4 DataForm

    - by rip
    I’m trying out the Silverlight 4 beta DataForm control. I don’t seem to be able to get the edit and paging options at the top of the control like I’ve seen in Silverlight 3 examples. Has something changed or am I doing something wrong? Here’s my code: <UserControl x:Class="SilverlightApplication7.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" xmlns:dataFormToolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm.Toolkit"> <Grid x:Name="LayoutRoot" Background="White"> <dataFormToolkit:DataForm HorizontalAlignment="Left" Margin="10" Name="myDataForm" VerticalAlignment="Top" /> </Grid> </UserControl> public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); this.Loaded += new RoutedEventHandler(MainPage_Loaded); } void MainPage_Loaded(object sender, RoutedEventArgs e) { Movie movie = new Movie(); myDataForm.CurrentItem = movie; } public enum Genres { Comedy, Fantasy, Drama, Thriller } public class Movie { public int MovieID { get; set; } public string Name { get; set; } public int Year { get; set; } public DateTime AddedOn { get; set; } public string Producer { get; set; } public Genres Genre { get; set; } } }

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  • javax.ejb.NoSuchEJBException after redeploying EJBs

    - by vetler
    Using Glassfish 3.0.1 ... If I have a web application accessing EJBs in another application remotely, and the remote application containing the EJBs is redeployed, I get a javax.ejb.NoSuchEJBException (see stacktrace below). Shouldn't this work? I can see that the EJB in question was successfully deployed, using the exact same JNDI name. Is there any other way to fix this than to restart the web application? It should be noted that in this particular example that the stacktrace is from, I'm accessing a servlet that injects the bean with CDI: public class StatusServlet extends HttpServlet { @Inject private StatusService statusService; @Override public void doGet(final HttpServletRequest req, final HttpServletResponse res) throws IOException { res.getWriter().write(statusService.getStatus()); } } The injection is done with the following producer to get the right EJB: public class StatusServiceProducer extends AbstractServiceProducer { @EJB(name = "StatusService") private StatusService service; @Produces public StatusService getService(final InjectionPoint ip) { return service; } } A producer is used to make it easier to wrap the service in a proxy, and to make it easier to change how the EJBs are looked up. The StatusService interface and implementation is as follows: @Stateless(name = "StatusService") public class StatusServiceImpl implements StatusService { private static final String OK = "OK"; public String getStatus() { // Some code return OK; } } public interface StatusService { String getStatus(); } Full stacktrace: [#|2011-01-12T10:45:28.273+0100|WARNING|glassfish3.0.1|javax.enterprise.system.container.web.com.sun.enterprise.web|_ThreadID=50;_ThreadName=http-thread-pool-8080-(1);|StandardWrapperValve[Load Balancer status servlet]: PWC1406: Servlet.service() for servlet Load Balancer status servlet threw exception javax.ejb.NoSuchEJBException at org.example.service._StatusService_Wrapper.getStatus(org/example/service/_StatusService_Wrapper.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at no.evote.service.cache.ServiceInvocationHandler.invoke(ServiceInvocationHandler.java:34) at $Proxy760.getStatus(Unknown Source) at no.evote.presentation.StatusServlet.doGet(StatusServlet.java:25) at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at net.balusc.http.multipart.MultipartFilter.doFilter(MultipartFilter.java:78) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:277) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:662) Caused by: java.rmi.NoSuchObjectException: CORBA OBJECT_NOT_EXIST 1330446338 No; nested exception is: org.omg.CORBA.OBJECT_NOT_EXIST: ----------BEGIN server-side stack trace---------- org.omg.CORBA.OBJECT_NOT_EXIST: vmcid: OMG minor code: 2 completed: No at com.sun.corba.ee.impl.logging.OMGSystemException.noObjectAdaptor(OMGSystemException.java:3457) at com.sun.corba.ee.impl.logging.OMGSystemException.noObjectAdaptor(OMGSystemException.java:3475) at com.sun.corba.ee.impl.oa.poa.POAFactory.find(POAFactory.java:222) at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.findObjectAdapter(CorbaServerRequestDispatcherImpl.java:450) at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(CorbaServerRequestDispatcherImpl.java:209) at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(CorbaMessageMediatorImpl.java:1841) at com.sun.corba.ee.impl.protocol.SharedCDRClientRequestDispatcherImpl.marshalingComplete(SharedCDRClientRequestDispatcherImpl.java:119) at com.sun.corba.ee.impl.protocol.CorbaClientDelegateImpl.invoke(CorbaClientDelegateImpl.java:235) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:187) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:147) at com.sun.corba.ee.impl.presentation.rmi.codegen.CodegenStubBase.invoke(CodegenStubBase.java:225) at no.evote.service.__StatusService_Remote_DynamicStub.getStatus(no/evote/service/__StatusService_Remote_DynamicStub.java) at no.evote.service._StatusService_Wrapper.getStatus(no/evote/service/_StatusService_Wrapper.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at no.evote.service.cache.ServiceInvocationHandler.invoke(ServiceInvocationHandler.java:34) at $Proxy760.getStatus(Unknown Source) at no.evote.presentation.StatusServlet.doGet(StatusServlet.java:25) at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at net.balusc.http.multipart.MultipartFilter.doFilter(MultipartFilter.java:78) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:277) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:662) Caused by: org.omg.PortableServer.POAPackage.AdapterNonExistent: IDL:omg.org/PortableServer/POA/AdapterNonExistent:1.0 at com.sun.corba.ee.impl.oa.poa.POAImpl.find_POA(POAImpl.java:1057) at com.sun.corba.ee.impl.oa.poa.POAFactory.find(POAFactory.java:218) ... 48 more ----------END server-side stack trace---------- vmcid: OMG minor code: 2 completed: No at com.sun.corba.ee.impl.javax.rmi.CORBA.Util.mapSystemException(Util.java:280) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:200) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:147) at com.sun.corba.ee.impl.presentation.rmi.codegen.CodegenStubBase.invoke(CodegenStubBase.java:225) at no.evote.service.__StatusService_Remote_DynamicStub.getStatus(no/evote/service/__StatusService_Remote_DynamicStub.java) ... 39 more Caused by: org.omg.CORBA.OBJECT_NOT_EXIST: ----------BEGIN server-side stack trace---------- org.omg.CORBA.OBJECT_NOT_EXIST: vmcid: OMG minor code: 2 completed: No at com.sun.corba.ee.impl.logging.OMGSystemException.noObjectAdaptor(OMGSystemException.java:3457) at com.sun.corba.ee.impl.logging.OMGSystemException.noObjectAdaptor(OMGSystemException.java:3475) at com.sun.corba.ee.impl.oa.poa.POAFactory.find(POAFactory.java:222) at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.findObjectAdapter(CorbaServerRequestDispatcherImpl.java:450) at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(CorbaServerRequestDispatcherImpl.java:209) at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(CorbaMessageMediatorImpl.java:1841) at com.sun.corba.ee.impl.protocol.SharedCDRClientRequestDispatcherImpl.marshalingComplete(SharedCDRClientRequestDispatcherImpl.java:119) at com.sun.corba.ee.impl.protocol.CorbaClientDelegateImpl.invoke(CorbaClientDelegateImpl.java:235) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:187) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.invoke(StubInvocationHandlerImpl.java:147) at com.sun.corba.ee.impl.presentation.rmi.codegen.CodegenStubBase.invoke(CodegenStubBase.java:225) at no.evote.service.__StatusService_Remote_DynamicStub.getStatus(no/evote/service/__StatusService_Remote_DynamicStub.java) at no.evote.service._StatusService_Wrapper.getStatus(no/evote/service/_StatusService_Wrapper.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at no.evote.service.cache.ServiceInvocationHandler.invoke(ServiceInvocationHandler.java:34) at $Proxy760.getStatus(Unknown Source) at no.evote.presentation.StatusServlet.doGet(StatusServlet.java:25) at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:343) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at net.balusc.http.multipart.MultipartFilter.doFilter(MultipartFilter.java:78) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:256) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:215) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:277) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:662) Caused by: org.omg.PortableServer.POAPackage.AdapterNonExistent: IDL:omg.org/PortableServer/POA/AdapterNonExistent:1.0 at com.sun.corba.ee.impl.oa.poa.POAImpl.find_POA(POAImpl.java:1057) at com.sun.corba.ee.impl.oa.poa.POAFactory.find(POAFactory.java:218) ... 48 more ----------END server-side stack trace---------- vmcid: OMG minor code: 2 completed: No at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.sun.corba.ee.impl.protocol.giopmsgheaders.MessageBase.getSystemException(MessageBase.java:913) at com.sun.corba.ee.impl.protocol.giopmsgheaders.ReplyMessage_1_2.getSystemException(ReplyMessage_1_2.java:129) at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.getSystemExceptionReply(CorbaMessageMediatorImpl.java:681) at com.sun.corba.ee.impl.protocol.CorbaClientRequestDispatcherImpl.processResponse(CorbaClientRequestDispatcherImpl.java:510) at com.sun.corba.ee.impl.protocol.SharedCDRClientRequestDispatcherImpl.marshalingComplete(SharedCDRClientRequestDispatcherImpl.java:153) at com.sun.corba.ee.impl.protocol.CorbaClientDelegateImpl.invoke(CorbaClientDelegateImpl.java:235) at com.sun.corba.ee.impl.presentation.rmi.StubInvocationHandlerImpl.privateInvoke(StubInvocationHandlerImpl.java:187) ... 42 more |#]

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  • Databinding between UserControls?

    - by Dave
    I've got a situation where one of my UserControls would like to display a list of strings in a droplist, and the ItemsSource is set to another UserControl's ObservableCollection. The consumer of this data has its droplist defined in XAML like this: <ComboBox Grid.Column="1" SelectedItem="{Binding MyItem, Mode=TwoWay}" ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.MyItems}" Margin="3"></ComboBox> MyItems is defined as an ObservableCollection<string> in the producer UserControl. Now everything works fine when the controls are loaded. As long as MyItems is populated first, and then the consumer UserControl is displayed, all of the items are there. I obviously don't get any errors in the Output Window or anything like that. The issue I have is that when the ObservableCollection is modified, those changes are not reflected in the consumer UserControl! I've never had this problem before, but all of my previous uses of ObservableCollection with updating the collection are within a single control, and databinding is not inter-UserControl. Is there something I did wrong? Is there a good way to actually debug this? Reed Copsey indicates here that inter-UserControl databinding is possible. Unfortunately, my favorite Bea Stollnitz article on WPF databinding debugging doesn't suggest anything that I could use for this particular problem.

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  • C++ thread safety - exchange data between worker and controller

    - by peterchen
    I still feel a bit unsafe about the topic and hope you folks can help me - For passing data (configuration or results) between a worker thread polling something and a controlling thread interested in the most recent data, I've ended up using more or less the following pattern repeatedly: Mutex m; tData * stage; // temporary, accessed concurrently // send data, gives up ownership, receives old stage if any tData * Send(tData * newData) { ScopedLock lock(m); swap(newData, stage); return newData; } // receiving thread fetches latest data here tData * Fetch(tData * prev) { ScopedLock lock(m); if (stage != 0) { // ... release prev prev = stage; stage = 0; } return prev; // now current } Note: This is not supposed to be a full producer-consumer queue, only the msot recent data is relevant. Also, I've skimmed ressource management somewhat here. When necessary I'm using two such stages: one to send config changes to the worker, and for sending back results. Now, my questions assuming that ScopedLock implements a full memory barrier: do stage and/or workerData need to be volatile? is volatile necessary for tData members? can I use smart pointers instead of the raw pointers - say boost::shared_ptr? Anything else that can go wrong? I am basically trying to avoid "volatile infection" spreading into tData, and minimize lock contention (a lock free implementation seems possible, too). However, I'm not sure if this is the easiest solution. ScopedLock acts as a full memory barrier. Since all this is more or less platform dependent, let's say Visual C++ x86 or x64, though differences/notes for other platforms are welcome, too. (a prelimenary "thanks but" for recommending libraries such as Intel TBB - I am trying to understand the platform issues here)

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  • IRequest / IResponse Pattern

    - by traderde
    I am trying to create an Interface-based Request/Response pattern for Web API requests to allow for asynchronous consumer/producer processing, but not sure how I would know what the underlying IResponse class is. public void Run() { List<IRequest> requests = new List<IRequest>(); List<IResponse> responses = new List<IResponse(); requests.Add(AmazonWebRequest); //should be object, trying to keep it simple requests.Add(EBayWebRequest); //should be object, trying to keep it simple foreach (IRequest req in requests) { responses.Add(req.GetResponse()); } foreach (IResponse resp in response) { typeof resp???? } } interface IRequest { IResponse GetResponse(); } interface IResponse { } public class AmazonWebServiceRequest : IRequest { public AmazonWebServiceRequest() { //get data; } public IResponse GetResponse() { AmazonWebServiceRequest request = new AmazonWebServiceRequest(); return (IResponse)request; } } public class AmazonWebServiceResponse : IResponse { XmlDocument _xml; public AmazonWebServiceResponse(XmlDocument xml) { _xml = xml; _parseXml(); } private void _parseXml() { //parse Xml into object; } } public class EBayWebRequest : IRequest { public EBayWebRequest () { //get data; } public IResponse GetResponse() { EBayWebRequest request = new EBayWebRequest(); return (IResponse)request; } } public class EBayWebResponse : IResponse { XmlDocument _xml; public EBayWebResponse(XmlDocument xml) { _xml = xml; _parseXml(); } private void _parseXml() { //parse Xml into object; } }

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  • How to make Stack.Pop threadsafe

    - by user260197
    I am using the BlockingQueue code posted in this question, but realized I needed to use a Stack instead of a Queue given how my program runs. I converted it to use a Stack and renamed the class as needed. For performance I removed locking in Push, since my producer code is single threaded. My problem is how can thread working on the (now) thread safe Stack know when it is empty. Even if I add another thread safe wrapper around Count that locks on the underlying collection like Push and Pop do, I still run into the race condition that access Count and then Pop are not atomic. Possible solutions as I see them (which is preferred and am I missing any that would work better?): Consumer threads catch the InvalidOperationException thrown by Pop(). Pop() return a nullptr when _stack-Count == 0, however C++-CLI does not have the default() operator ala C#. Pop() returns a boolean and uses an output parameter to return the popped element. Here is the code I am using right now: generic <typename T> public ref class ThreadSafeStack { public: ThreadSafeStack() { _stack = gcnew Collections::Generic::Stack<T>(); } public: void Push(T element) { _stack->Push(element); } T Pop(void) { System::Threading::Monitor::Enter(_stack); try { return _stack->Pop(); } finally { System::Threading::Monitor::Exit(_stack); } } public: property int Count { int get(void) { System::Threading::Monitor::Enter(_stack); try { return _stack->Count; } finally { System::Threading::Monitor::Exit(_stack); } } } private: Collections::Generic::Stack<T> ^_stack; };

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  • Surprising results with .NET multi-theading algorithm

    - by Myles J
    Hi, I've recently wrote a C# console time tabling algorithm that is based on a combination of a genetic algorithm with a few brute force routines thrown in. The initial results were promising but I figured I could improve the performance by splitting the brute force routines up to run in parallel on multi processor architectures. To do this I used the well documented Producer/Consumer model (as documented in this fantastic article http://www.albahari.com/threading/part2.aspx#_ProducerConsumerQWaitHandle). I changed my code to create one thread per logical processor during the brute force routines. The performance gains on my work station were very pleasing. I am running Windows XP on the following hardware: Intel Core 2 Quad CPU 2.33 GHz 3.49 GB RAM Initial tests indicated average performance gains of approx 40% when using 4 threads. The next step was to deploy the new multi-threading version of the algorithm to our higher spec UAT server. Here is the spec of our UAT server: Windows 2003 Server R2 Enterprise x64 8 cpu (Quad-Core) AMD Opteron 2.70 GHz 255 GB RAM After running the first round of tests we were all extremely surprised to find that the algorithm actually runs slower on the high spec W2003 server than on my local XP work station! In fact the tests seem to indicate that it doesn't matter how many threads are generated (tests were ran with the app spawning between 2 to 32 threads). The algorithm always runs significantly slower on the UAT W2003 server? How could this be? Surely the app should run faster on a 8 cpu (Quad-Core) than my 2 Quad work station? Why are we seeing no performance gains with the multi-threading on the W2003 server whilst the XP workstation tests show gains of up to 40%? Any help or pointers would be appreciated. Regards Myles

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  • Niewbie OutOfMemory problem

    - by Nick
    So I am trying to create a producer/consumer type scala app. The LoopControl just sends a message to the MessageReceiver continoually. The MessageReceiver then delegates work to the MessageCreatorActor (whose work is to check a map for an object, and if not found create one and start it up). Each MessageActor created by this MessageCreatorActor is associated with an Id. Eventually this is where I want to do business logic. But I run out of memory after 15 minutes. Any help is appreciated import scala.actors.Actor import java.util.HashMap; import scala.actors.Actor._ case object LoopControl case object MessageReceiver case object MessageActor case object MessageActorCreator class MessageReceiver(msg: String) extends Actor { var messageActorMap = new HashMap[String, MessageActor] val messageCreatorActor = new MessageActorCreator(null, null) def act() { messageCreatorActor.start loop { react { case MessageActor(messageId) = if (msg.length() 0) { var messageActor = messageActorMap.get(messageId); if(messageActor == null) { messageCreatorActor ! MessageActorCreator(messageId, messageActorMap) }else { messageActor ! MessageActor } } } } } } case class MessageActorCreator(msg:String, messageActorMap: HashMap[String, MessageActor]) extends Actor { def act() { loop { react { case MessageActorCreator(messageId, messageActorMap) = if(messageId != null ) { var messageActor = new MessageActor(messageId); messageActorMap.put(messageId, messageActor) println(messageActorMap) messageActor.start messageActor ! MessageActor } } } } } class LoopControl(messageReceiver:MessageReceiver) extends Actor { var count : Int = 0; def act() { while (true) { messageReceiver ! MessageActor ("00-122-0X95-FEC0" + count) //Thread.sleep(100) count = count +1; if(count 5) { count = 0; } } } } case class MessageActor(msg: String) extends Actor { def act() { loop { react { case MessageActor = println() println("MessageActor: Got something- " + msg) } } } } object messages extends Application { val messageReceiver = new MessageReceiver("bootstrap") val loopControl = new LoopControl(messageReceiver) messageReceiver.start loopControl.start }

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  • How to use SQLAlchemy to dump an SQL file from query expressions to bulk-insert into a DBMS?

    - by Mahmoud Abdelkader
    Please bear with me as I explain the problem, how I tried to solve it, and my question on how to improve it is at the end. I have a 100,000 line csv file from an offline batch job and I needed to insert it into the database as its proper models. Ordinarily, if this is a fairly straight-forward load, this can be trivially loaded by just munging the CSV file to fit a schema, but I had to do some external processing that requires querying and it's just much more convenient to use SQLAlchemy to generate the data I want. The data I want here is 3 models that represent 3 pre-exiting tables in the database and each subsequent model depends on the previous model. For example: Model C --> Foreign Key --> Model B --> Foreign Key --> Model A So, the models must be inserted in the order A, B, and C. I came up with a producer/consumer approach: - instantiate a multiprocessing.Process which contains a threadpool of 50 persister threads that have a threadlocal connection to a database - read a line from the file using the csv DictReader - enqueue the dictionary to the process, where each thread creates the appropriate models by querying the right values and each thread persists the models in the appropriate order This was faster than a non-threaded read/persist but it is way slower than bulk-loading a file into the database. The job finished persisting after about 45 minutes. For fun, I decided to write it in SQL statements, it took 5 minutes. Writing the SQL statements took me a couple of hours, though. So my question is, could I have used a faster method to insert rows using SQLAlchemy? As I understand it, SQLAlchemy is not designed for bulk insert operations, so this is less than ideal. This follows to my question, is there a way to generate the SQL statements using SQLAlchemy, throw them in a file, and then just use a bulk-load into the database? I know about str(model_object) but it does not show the interpolated values. I would appreciate any guidance for how to do this faster. Thanks!

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  • Using the Queue class in Python 2.6

    - by voipme
    Let's assume I'm stuck using Python 2.6, and can't upgrade (even if that would help). I've written a program that uses the Queue class. My producer is a simple directory listing. My consumer threads pull a file from the queue, and do stuff with it. If the file has already been processed, I skip it. The processed list is generated before all of the threads are started, so it isn't empty. Here's some pseudo-code. import Queue, sys, threading processed = [] def consumer(): while True: file = dirlist.get(block=True) if file in processed: print "Ignoring %s" % file else: # do stuff here dirlist.task_done() dirlist = Queue.Queue() for f in os.listdir("/some/dir"): dirlist.put(f) max_threads = 8 for i in range(max_threads): thr = Thread(target=consumer) thr.start() dirlist.join() The strange behavior I'm getting is that if a thread encounters a file that's already been processed, the thread stalls out and waits until the entire program ends. I've done a little bit of testing, and the first 7 threads (assuming 8 is the max) stop, while the 8th thread keeps processing, one file at a time. But, by doing that, I'm losing the entire reason for threading the application. Am I doing something wrong, or is this the expected behavior of the Queue/threading classes in Python 2.6?

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  • Communication between lexer and parser

    - by FredOverflow
    Every time I write a simple lexer and parser, I stumble upon the same question: how should the lexer and the parser communicate? I see four different approaches: The lexer eagerly converts the entire input string into a vector of tokens. Once this is done, the vector is fed to the parser which converts it into a tree. This is by far the simplest solution to implement, but since all tokens are stored in memory, it wastes a lot of space. Each time the lexer finds a token, it invokes a function on the parser, passing the current token. In my experience, this only works if the parser can naturally be implemented as a state machine like LALR parsers. By contrast, I don't think it would work at all for recursive descent parsers. Each time the parser needs a token, it asks the lexer for the next one. This is very easy to implement in C# due to the yield keyword, but quite hard in C++ which doesn't have it. The lexer and parser communicate through an asynchronous queue. This is commonly known under the title "producer/consumer", and it should simplify the communication between the lexer and the parser a lot. Does it also outperform the other solutions on multicores? Or is lexing too trivial? Is my analysis sound? Are there other approaches I haven't thought of? What is used in real-world compilers? It would be really cool if compiler writers like Eric Lippert could shed some light on this issue.

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  • Updating a C# 2.0 events example to be idiomatic with C# 3.5?

    - by Damien Wildfire
    I have a short events example from .NET 2.0 that I've been using as a reference point for a while. We're now upgrading to 3.5, though, and I'm not clear on the most idiomatic way to do things. How would this simple events example get updated to reflect idioms that are now available in .NET 3.5? // Args class. public class TickArgs : EventArgs { private DateTime TimeNow; public DateTime Time { set { TimeNow = value; } get { return this.TimeNow; } } } // Producer class that generates events. public class Metronome { public event TickHandler Tick; public delegate void TickHandler(Metronome m, TickArgs e); public void Start() { while (true) { System.Threading.Thread.Sleep(3000); if (Tick != null) { TickArgs t = new TickArgs(); t.Time = DateTime.Now; Tick(this, t); } } } } // Consumer class that listens for events. public class Listener { public void Subscribe(Metronome m) { m.Tick += new Metronome.TickHandler(HeardIt); } private void HeardIt(Metronome m, TickArgs e) { System.Console.WriteLine("HEARD IT AT {0}",e.Time); } } // Example. public class Test { static void Main() { Metronome m = new Metronome(); Listener l = new Listener(); l.Subscribe(m); m.Start(); } }

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  • When to use a foreign key in MySQL

    - by Mel
    Is there official guidance or a threshold to indicate when it is best practice to use a foreign key in a MySQL database? Suppose you created a table for movies. One way to do it is to integrate the producer and director data into the same table. (movieID, movieName, directorName, producerName). However, suppose most directors and producers have worked on many movies. Would it be best to create two other tables for producers and directors, and use a foreign key in the movie table? When does it become best practice to do this? When many of the directors and producers are appearing several times in the column? Or is it best practice to employ a foreign key approach at the start? While it seems more efficient to use a foreign key, it also raises the complexity of the database. So when does the trade off between complexity and normalization become worth it? I'm not sure if there is a threshold or a certain number of cell repetitions that makes it more sensible to use a foreign key. I'm thinking about a database that will be used by hundreds of users, many concurrently. Many thanks!

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  • Turn based synchronization between threads

    - by Amarus
    I'm trying to find a way to synchronize multiple threads having the following conditions: * There are two types of threads: 1. A single "cyclic" thread executing an infinite loop to do cyclic calculations 2. Multiple short-lived threads not started by the main thread * The cyclic thread has a sleep duration between each cycle/loop iteration * The other threads are allowed execute during the inter-cycle sleep of the cyclic thread: - Any other thread that attempts to execute during an active cycle should be blocked - The cyclic thread will wait until all other threads that are already executing to be finished Here's a basic example of what I was thinking of doing: // Somewhere in the code: ManualResetEvent manualResetEvent = new ManualResetEvent(true); // Allow Externally call CountdownEvent countdownEvent = new CountdownEvent(1); // Can't AddCount a CountdownEvent with CurrentCount = 0 void ExternallyCalled() { manualResetEvent.WaitOne(); // Wait until CyclicCalculations is having its beauty sleep countdownEvent.AddCount(); // Notify CyclicCalculations that it should wait for this method call to finish before starting the next cycle Thread.Sleep(1000); // TODO: Replace with actual method logic countdownEvent.Signal(); // Notify CyclicCalculations that this call is finished } void CyclicCalculations() { while (!stopCyclicCalculations) { manualResetEvent.Reset(); // Block all incoming calls to ExternallyCalled from this point forward countdownEvent.Signal(); // Dirty workaround for the issue with AddCount and CurrentCount = 0 countdownEvent.Wait(); // Wait until all of the already executing calls to ExternallyCalled are finished countdownEvent.Reset(); // Reset the CountdownEvent for next cycle. Thread.Sleep(2000); // TODO: Replace with actual method logic manualResetEvent.Set(); // Unblock all threads executing ExternallyCalled Thread.Sleep(1000); // Inter-cycles delay } } Obviously, this doesn't work. There's no guarantee that there won't be any threads executing ExternallyCalled that are in between manualResetEvent.WaitOne(); and countdownEvent.AddCount(); at the time the main thread gets released by the CountdownEvent. I can't figure out a simple way of doing what I'm after, and almost everything that I've found after a lengthy search is related to producer/consumer synchronization which I can't apply here.

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  • Cannot locate record in delphi ADO query

    - by Danatela
    I can't locate any record in TADOQuery using PK. First, I was trying to use standard Locate method: PPUQuery.Locate('ID', SpPlansQuery['PPONREC'], []); It always returns False, but manual search (passing the whole query matching ID with given PPONREC which is really slow) finds the desired row. I tried using loPartialKey and switched CursorLocation of query to clUseServer, but it didn't help. Next, I tried to filter my PPUQuery: PPUQuery.Filter := 'ID = ' + VarToStr(SpPlansQuery['PPONREC']); PPUQuery.Filtered := True; PPUQuery.First; But after that the PPUQuery.Eof is True and PPUQuery.RecordCount equals 0. Underlying database is Oracle 9 and the ID is of type INTEGER and is PK of table TPORDER_CMK. PPUQuery.SQL is: SELECT tp.*, la.*, lm.*, ld.*, ld1.*, to_cmk.* FROM ppu_plan.tporder_cmk tp JOIN PPU_PLAN.LARTICLES la ON TP.ARTICLE = LA.ID JOIN PPU_PLAN.LMATERIAL lm ON TP.MATERIAL = lm.id JOIN PPU_PLAN.LCADEP ld ON TP.CADEP = LD.ID JOIN PPU_PLAN.LCADEP ld1 ON TP.PRODUCER = LD1.ID JOIN PPU_PLAN.TORDER_CMK to_cmk ON TP.order_id=TO_cmk.ID WHERE TP.PLAN_ID = :pplan_id What should I try next and how to solve this problem?

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  • How (and if) to write a single-consumer queue using the task parallel library?

    - by Eric
    I've heard a bunch of podcasts recently about the TPL in .NET 4.0. Most of them describe background activities like downloading images or doing a computation, using tasks so that the work doesn't interfere with a GUI thread. Most of the code I work on has more of a multiple-producer / single-consumer flavor, where work items from multiple sources must be queued and then processed in order. One example would be logging, where log lines from multiple threads are sequentialized into a single queue for eventual writing to a file or database. All the records from any single source must remain in order, and records from the same moment in time should be "close" to each other in the eventual output. So multiple threads or tasks or whatever are all invoking a queuer: lock( _queue ) // or use a lock-free queue! { _queue.enqueue( some_work ); _queueSemaphore.Release(); } And a dedicated worker thread processes the queue: while( _queueSemaphore.WaitOne() ) { lock( _queue ) { some_work = _queue.dequeue(); } deal_with( some_work ); } It's always seemed reasonable to dedicate a worker thread for the consumer side of these tasks. Should I write future programs using some construct from the TPL instead? Which one? Why?

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  • Seriously, It’s Time to Get Your Content Act Together

    - by Mike Stiles
    Branded content, content marketing, social content, brand journalism, we’re seeing those terms more and more. Why? The technology tools are coming together. We should know. We can gather big data, crunch it, listen to the public, moderate, respond, get to know the customer intimately, know what they like, know what they want, we can target, distribute, amplify, measure engagement and reaction, modify strategy and even automate a great deal of all that. An amazing machine, a sleek, smooth-running engine has been built such that all the parts can interact and work together to deliver peak performance and maximum output. But that engine isn’t going anywhere without any gas. Content is the gas. Yes, we curate other people’s content. We can siphon their gas. There’s tech to help with that too. But as for the creation of original, worthwhile content made for a specific audience, our audience, machines can’t do that…at least not yet. Curated content is great. But somebody has to originate the content for it to be curated and shared. And since the need for good, curated content is obviously large and the desire to share is there, it’s a winning proposition for a brand to be a consistent producer of original content. And yet, it feels like content is an issue we’re avoiding. There’s a reluctance to build a massive pipeline if you have no idea what you’re going to run through it. The C-suite often doesn’t know what content is, that it’s different from ads, where to get it, who makes it, how long it should be, what the point of it is if there’s no hard sell of the product, what it costs, how to use it, how to measure it, how to make sure it’s good, or how to make sure it will keep flowing. It could be the reason many brands aren’t pulling the trigger on socially enabling the enterprise. And that’s a shame, because there are a lot of creative, daring, experimental, uniquely talented entertainers and journalists chomping at the bit to execute content for brands. But for many corporate executives, content is “weird,” and the people who make it are even weirder. The content side of the equation is human. It’s art, but art that can be informed by data. The natural inclination is for brands to turn to their agencies for such creative endeavors. But agencies are falling into one of two categories. They’re failing to transition from ads to content. In “Content Era, What’s the Role of Agencies?” Alexander Jutkowitz says agencies were made for one-hit campaigns, not ongoing content. Or, they’re ready and capable but can’t get clients to do the right things. Agencies have to make money, even if it means continuing to do the wrong things because that’s all the client will agree to. So what we wind up with in the pipeline is advertising, marketing-heavy content, content that was obviously created or spearheaded by non-creative executives, random & inconsistent content, copy written for SEO bots, and other completely uninteresting nightmares. Frank Rose, author of “The Art of Immersion,” writes, “Content without story and excitement is noise pollution.” In the old days, you made an ad and inserted it into shows made by people who knew what they were doing. You could bask in that show’s success and leverage their audience. Now, you are tasked with attracting, amassing and holding your own audience. You may just want to make, advertise and sell your widgets. But now there’s a war on for a precious commodity, attention. People are busy. They have filters to keep uninteresting and irrelevant things out. They value their time and expect value back when they give it up. Joe Pulizzi, founder of the Content Marketing Institute, says, "Your customers don't care about you, your products, your services…they care about themselves, their wants and their needs." Is it worth getting serious about content and doing it right? 61% of consumers feel better about a company that delivers custom content (Custom Content Council). Interesting content is one of the top 3 reasons people follow brands on social (Content+). 78% of consumers think organizations that provide custom content want to build good relationships with them (TMG Custom Media). On the B2B side, 80% of business decision makers prefer to get company info in a series of articles vs. an ad. So what’s the hang-up? Cited barriers to content marketing are lack of human resources (42%) and lack of budget (35%). 54% of brands don’t have a single on-site, dedicated content creator. And only 38% of brands have a content marketing strategy. Tech has built the biggest, most incredible stage for brands that’s ever been built. Putting something on that stage is your responsibility. Do a bad show, or no show at all, and you’ll be the beautiful, talented actress that never got discovered. @mikestilesPhoto: Gabriella Fabbri, stock.xchng

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