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  • Get two records from PLSQL cursor

    - by Hany
    My question is short. I create a cursor to get some values from my table. I want to get the current record of cursor (the fetched record) and the next record from the cursor without fetching it, because I want to make a calculation over the current record and the next record. In traditional programming it's a simple operation; you can do it with a for index by increasing it by 1. Do you have any suggestions?

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  • selectOneMenu - java.lang.NullPointerException when adding record to the database (JSF2 and JPA2-OpenJPA)

    - by rogie
    Good day to all; I'm developing a program using JSF2 and JPA2 (OpenJPA). Im also using IBM Rapid App Dev't v8 with WebSphere App Server v8 test server. I have two simple entities, Employee and Department. Each Department has many Employees and each Employee belongs to a Department (using deptno and workdept). My problem occurs when i tried to add a new employee and selecting a department from a combo box (using selectOneMenu - populated from Department table): when i run the program, the following error messages appeared: An Error Occurred: java.lang.NullPointerException Caused by: java.lang.NullPointerException - java.lang.NullPointerException I also tried to make another program using Deptno and Workdept as String instead of integer, still doesn't work. Pls help. Im also a newbie. Tnx and God bless. Below are my codes, configurations and setup. Just tell me if there are some codes that I forgot to include. Im also using Derby v10.5 as my database: CREATE SCHEMA RTS; CREATE TABLE RTS.DEPARTMENT (DEPTNO INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), DEPTNAME VARCHAR(30)); ALTER TABLE RTS.DEPARTMENT ADD CONSTRAINT PK_DEPARTMNET PRIMARY KEY (DEPTNO); CREATE TABLE RTS.EMPLOYEE (EMPNO INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), NAME VARCHAR(50), WORKDEPT INTEGER); ALTER TABLE RTS.EMPLOYEE ADD CONSTRAINT PK_EMPLOYEE PRIMARY KEY (EMPNO); Employee and Department Entities package rts.entities; import java.io.Serializable; import javax.persistence.*; @Entity public class Employee implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int empno; private String name; //bi-directional many-to-one association to Department @ManyToOne @JoinColumn(name="WORKDEPT") private Department department; ....... getter and setter methods package rts.entities; import java.io.Serializable; import javax.persistence.*; import java.util.List; @Entity public class Department implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.IDENTITY) private int deptno; private String deptname; //bi-directional many-to-one association to Employee @OneToMany(mappedBy="department") private List<Employee> employees; ....... getter and setter methods JSF 2 snipet using combo box (populated from Department table) <tr> <td align="left">Department</td> <td style="width: 5px">&#160;</td> <td><h:selectOneMenu styleClass="selectOneMenu" id="department1" value="#{pc_EmployeeAdd.employee.department}"> <f:selectItems value="#{DepartmentManager.departmentSelectList}" id="selectItems1"></f:selectItems> </h:selectOneMenu></td> </tr> package rts.entities.controller; import com.ibm.jpa.web.JPAManager; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import com.ibm.jpa.web.NamedQueryTarget; import com.ibm.jpa.web.Action; import javax.persistence.PersistenceUnit; import javax.annotation.Resource; import javax.transaction.UserTransaction; import rts.entities.Department; import java.util.List; import javax.persistence.Query; import java.util.ArrayList; import java.text.MessageFormat; import javax.faces.model.SelectItem; @SuppressWarnings("unchecked") @JPAManager(targetEntity = rts.entities.Department.class) public class DepartmentManager { ....... public List<SelectItem> getDepartmentSelectList() { List<Department> departmentList = getDepartment(); List<SelectItem> selectList = new ArrayList<SelectItem>(); MessageFormat mf = new MessageFormat("{0}"); for (Department department : departmentList) { selectList.add(new SelectItem(department, mf.format( new Object[] { department.getDeptname() }, new StringBuffer(), null).toString())); } return selectList; } Converter: package rts.entities.converter; import javax.faces.component.UIComponent; import javax.faces.context.FacesContext; import javax.faces.convert.Converter; import rts.entities.Department; import rts.entities.controller.DepartmentManager; import com.ibm.jpa.web.TypeCoercionUtility; public class DepartmentConverter implements Converter { public Object getAsObject(FacesContext facesContext, UIComponent arg1, String entityId) { DepartmentManager departmentManager = (DepartmentManager) facesContext .getApplication().createValueBinding("#{DepartmentManager}") .getValue(facesContext); int deptno = (Integer) TypeCoercionUtility.coerceType("int", entityId); Department result = departmentManager.findDepartmentByDeptno(deptno); return result; } public String getAsString(FacesContext arg0, UIComponent arg1, Object object) { if (object instanceof Department) { return "" + ((Department) object).getDeptno(); } else { throw new IllegalArgumentException("Invalid object type:" + object.getClass().getName()); } } } Method for Add button: public String createEmployeeAction() { EmployeeManager employeeManager = (EmployeeManager) getManagedBean("EmployeeManager"); try { employeeManager.createEmployee(employee); } catch (Exception e) { logException(e); } return ""; } faces-conf.xml <converter> <converter-for-class>rts.entities.Department</converter-for-class> <converter-class>rts.entities.converter.DepartmentConverter</converter-class> </converter> Stack trace javax.faces.FacesException: java.lang.NullPointerException at org.apache.myfaces.shared_impl.context.ExceptionHandlerImpl.wrap(ExceptionHandlerImpl.java:241) at org.apache.myfaces.shared_impl.context.ExceptionHandlerImpl.handle(ExceptionHandlerImpl.java:156) at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:258) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:191) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1147) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:722) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:449) at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:178) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.invokeFilters(WebAppFilterManager.java:1020) at com.ibm.ws.webcontainer.servlet.CacheServletWrapper.handleRequest(CacheServletWrapper.java:87) at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:886) at com.ibm.ws.webcontainer.WSWebContainer.handleRequest(WSWebContainer.java:1655) at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:195) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:452) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewRequest(HttpInboundLink.java:511) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.processRequest(HttpInboundLink.java:305) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:276) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113) at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165) at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217) at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161) at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:138) at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:204) at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:775) at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:905) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1650) Caused by: java.lang.NullPointerException at rts.entities.converter.DepartmentConverter.getAsString(DepartmentConverter.java:29) at org.apache.myfaces.shared_impl.renderkit.RendererUtils.getConvertedStringValue(RendererUtils.java:656) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.getSubmittedOrSelectedValuesAsSet(HtmlRendererUtils.java:444) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.internalRenderSelect(HtmlRendererUtils.java:421) at org.apache.myfaces.shared_impl.renderkit.html.HtmlRendererUtils.renderMenu(HtmlRendererUtils.java:359) at org.apache.myfaces.shared_impl.renderkit.html.HtmlMenuRendererBase.encodeEnd(HtmlMenuRendererBase.java:76) at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:519) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:626) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at javax.faces.component.UIComponent.encodeAll(UIComponent.java:622) at org.apache.myfaces.view.facelets.FaceletViewDeclarationLanguage.renderView(FaceletViewDeclarationLanguage.java:1320) at org.apache.myfaces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:263) at org.apache.myfaces.lifecycle.RenderResponseExecutor.execute(RenderResponseExecutor.java:85) at org.apache.myfaces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:239) ... 24 more

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  • What are interesting ideas for experimenting with Artificial Neural Networks?

    - by Gerald Kaszuba
    I'm after a list of possible neural network implementations that one can do to learn how to use it. What other possibilities are there? Here's the list so far: Games tic-tac-toe Connect 4 Chess Go Visual recognition Character recognition (typefaces, letters, numbers, etc) Facial recognition Audio recognition Language detection Male vs female Word recognition Language detection (natural, programming)

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  • Looking for a good book on microprocessor internals

    - by David Holm
    I'm looking for a good book on how modern microprocessors are designed and work as I would like to increase my understanding of what makes them tick. Something that covers pipelines, superscalar architectures, caches etc. A book that is suitable for a programmer with several years of experience and has done and understands assembly programming and machine language, so basically not "CPUs for Dummies" or anything such. What books do people who design today's processors read for instance?

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  • Software tools for allowing end users to reprogram interfaces

    - by iceman
    What would be the examples of commercial software products (specially web-services) which allow the end user to reprogram their user-interface? I mean end users who do not know programming and they are allowed to add more functionality. One way of doing it is allowing XML gadgets like iGoogle does. What are the other approaches and also the technologies enabling them? This would be a futuristic application like collaborative software development for users.

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  • Open-stackoverflow installation/download info

    - by fmsf
    Hey, You probably already know about this I guess it's a programming question. I've been trying to find with google the info, but the amount of results using "open stackoverflow" pointing to questions here in stackoverflow is making the search a bit hard. So what better place to ask than here. Where can i find information/documentation on how to install/use/extend the SO q&a system? I want to create a clone for a local community from my city.

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  • Haskell newbie on types

    - by garulfo
    I'm completely new to Haskell (and more generally to functional programming), so forgive me if this is really basic stuff. To get more than a taste, I try to implement in Haskell some algorithmic stuff I'm working on. I have a simple module Interval that implements intervals on the line. It contains the type data Interval t = Interval t t the helper function makeInterval :: (Ord t) => t -> t -> Interval t makeInterval l r | l <= r = Interval l r | otherwise = error "bad interval" and some utility functions about intervals. Here, my interest lies in multidimensional intervals (d-intervals), those objects that are composed of d intervals. I want to separately consider d-intervals that are the union of d disjoint intervals on the line (multiple interval) from those that are the union of d interval on d separate lines (track interval). With distinct algorithmic treatments in mind, I think it would be nice to have two distinct types (even if both are lists of intervals here) such as import qualified Interval as I -- Multilple interval newtype MInterval t = MInterval [I.Interval t] -- Track interval newtype TInterval t = TInterval [I.Interval t] to allow for distinct sanity checks, e.g. makeMInterval :: (Ord t) => [I.Interval t] -> MInterval t makeMInterval is = if foldr (&&) True [I.precedes i i' | (i, i') <- zip is (tail is)] then (MInterval is) else error "bad multiple interval" makeTInterval :: (Ord t) => [I.Interval t] -> TInterval t makeTInterval = TInterval I now get to the point, at last! But some functions are naturally concerned with both multiple intervals and track intervals. For example, a function order would return the number of intervals in a multiple interval or a track interval. What can I do? Adding -- Dimensional interval data DInterval t = MIntervalStuff (MInterval t) | TIntervalStuff (TInterval t) does not help much, since, if I understand well (correct me if I'm wrong), I would have to write order :: DInterval t -> Int order (MIntervalStuff (MInterval is)) = length is order (TIntervalStuff (TInterval is)) = length is and call order as order (MIntervalStuff is) or order (TIntervalStuff is) when is is a MInterval or a TInterval. Not that great, it looks odd. Neither I want to duplicate the function (I have many functions that are concerned with both multiple and track intevals, and some other d-interval definitions such as equal length multiple and track intervals). I'm left with the feeling that I'm completely wrong and have missed some important point about types in Haskell (and/or can't forget enough here about OO programming). So, quite a newbie question, what would be the best way in Haskell to deal with such a situation? Do I have to forget about introducing MInterval and TInterval and go with one type only? Thanks a lot for your help, Garulfo

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  • What's your all-time creativity problem?

    - by furtelwart
    Sometimes, you stumble with programming. Sometimes, it's a lack of creativity, sometimes, you need a new solution. But there are a lot of situations, you stick in, every time they occur. For myself, it's when I have to create the interface between model and viewer. I designed my data structure very well and drew a GUI prototype, but the missing link won't be written. What are your personal barricades in developing projects?

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  • C++ OpenSource project for beginner programmer?

    - by VeminZ
    I`m a beginner C++ programmer. And I want to pursue my career in system- and driver-programming. Can you suggest me an opensource projects to I improve my skills in low-level development? I am looking for a project with the following characteristic: - on C\C++ language based - a small project with a small amount of code, yet - UNIX-based systems designed Do you know that something like this?

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  • Are there people using scheme out there?

    - by Nick
    Hey, I have just started to study computer sciences at the university where they teach us programming in scheme. Since i have learned c++ for the last 6 years, scheme appears a little odd to me. But they tell me you can write any program you can write in C or Java with it. Is anybody really using this language?

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  • scp via java

    - by Lloyd Meinholz
    What is the best method of performing an scp transfer via the Java programming language? It seems I may be able to perform this via JSSE, JSch or the bouncy castle java libraries. None of these solutions seem to have an easy answer.

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  • How can I explain to dspam that the user "brandon" is the same as "brandon@mydomain"

    - by Brandon Craig Rhodes
    I am using dspam for spam filtering by running the "dspamd" daemon under Ubuntu 9.10 and then setting up a Postfix rule that says: smtpd_recipient_restrictions = ... check_client_access pcre:/etc/postfix/dspam_everything ... where that PCRE map looks like this: /./ FILTER lmtp:[127.0.0.1]:11124 This works well, and means that all users on my system get all of their email, whether "dspam" thinks it is innocent or not, and have the option of filtering on its decisions or ignoring them. The problem comes when I want to train dspam using my email archives. After reading about the "dspam" command, I tried this on the files in my Inbox and spam boxes (which date from when I was using another filtering solution): for file in Mail/Inbox/*; do cat $file | dspam --class=innocent --source=corpus; done for file in Mail/spam/*; do cat $file | dspam --class=spam --source=corpus; done The symptom I noticed after doing all of this was that dspam was horrible at classifying spam — it couldn't find any! The problem, when I tracked it down, was that I was training the user "brandon" with the above commands, but the incoming email was instead compared against the username "brandon@mydomain", so it was running against a completely empty training database! So, what can I do to make the above commands actually train my fully-qualified email address rather than my bare username? I would like to avoid having to run "dspam" as root with a "--user" option. I would have expected that the "dspam" configuration files would have had an "append_domain" attribute or something with which to decorate local usernames with an appropriate email domain, but I can't find any such thing. When I used to use the Berkeley DB backend to "dspam", I solved this problem by creating a symlink from one of the databases to the other. :-) But that solution eventually died because the BDB backend is not thread-safe, so now I have moved to the PostgreSQL back-end and need a way to solve the problem there. And, no, the table where it keeps usernames has a UNIQUE constraint that prevents me from listing both usernames as mapping to the same ID. :-)

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  • Fixing LOD gaps, T-junctions

    - by Jaka Jancar
    I'm creating a heightmap renderer. One of the examples for solving gaps when doing LOD I found is this: (from Game Programming Gems 2 - Greg Snook - Simplified Terrain using Interlocking Tiles) Wouldn't this still produce a gap, if the three vertices encircled with red were not co-linear? Shouldn't the middle triangle be split into two, as I marked with the orange line? Am I misunderstanding the problem, or is there a mistake in the example?

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  • What was your most useful/inspiring computer science course?

    - by MPelletier
    I'm currently taking one course per semester, remotely, in a short 5 year program. My aim is to get better at my trade (programming and analysis, not surprisingly). However, I find that I'm not inspired by my choice of classes for next semester. Maybe I'm being too judgmental. I'd like to know what positive experience was gained from a course in particular. Have ou had a course that turned out to be an idea catalyst?

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  • .Net Library for parsing source code files?

    - by Jörg Battermann
    Does anyone know of a good .NET library that allows me to parse source code files, but not only .NET source code files (like java, perl, ruby, etc)? I need programmatic access to the contents of various source code files (e.g. class/method /parameter names, types, etc.). Has anyone come across something like this? I know within .NET it is reasonably possible and there are some libraries out there, but I need that to be abstracted to more types of programming languages.

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  • Error compiling Win32 API GUI code with MinGW

    - by Eric Larsen
    Hey guys, this is my first post. I'm just getting started with win32 API programming in C++ and I'm having trouble compiling the winnie tutorial (http://www.relisoft.com/win32/winnie.html) with MinGW. My input and output: C:\Users\Eric\Projects g++ winnie.cpp -o winnie.exe /mingw/lib/libmingw32.a(main.o):main.c:(.text+0xd2): undefined reference to 'WinMain@16' collect2: ld returned 1 exit status Any help would be very much appreciated.

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  • Receiving data with Winsock

    - by Tamir
    Right now, I'm programming the networking for my online game, and I'm not really sure what to do about receiving data. The problem is that I can't really guess the packet's size, so I thought of reading just 4 bytes from the packet and converting them to an int to know what's the packet's size. Then I'll just create a buffer in that size and receive the rest of the packet, is that a good idea? For your information, I'm using non-blocking i/o.

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  • Communicating with a MW-3170 magnetic card reader

    - by stukelly
    One of our customers has asked if we can interface with a serial magnetic card reader/encoder from a old EPOS system. The device has no make only the MW-3170 model number. Does anybody know how I can communicate with the device? I am currently looking for a programming manual on Google, without much success.

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  • C++ vs Matlab vs Python as a main language for Computer Vision Research

    - by Hough
    Hi all, Firstly, sorry for a somewhat long question but I think that many people are in the same situation as me and hopefully they can also gain some benefit from this. I'll be starting my PhD very soon which involves the fields of computer vision, pattern recognition and machine learning. Currently, I'm using opencv (2.1) C++ interface and I especially like its powerful Mat class and the overloaded operations available for matrix and image operations and seamless transformations. I've also tried (and implemented many small vision projects) using opencv python interface (new bindings; opencv 2.1) and I really enjoy python's ability to integrate opencv, numpy, scipy and matplotlib. But recently, I went back to opencv C++ interface because I felt that the official python new bindings were not stable enough and no overloaded operations are available for matrices and images, not to mention the lack of machine learning modules and slow speeds in certain operations. I've also used Matlab extensively in the past and although I've used mex files and other means to speed up the program, I just felt that Matlab's performance was inadequate for real-time vision tasks, be it for fast prototyping or not. When the project becomes larger and larger, many tasks have to be re-written in C and compiled into Mex files increasingly and Matlab becomes nothing more than a glue language. Here comes the sub-questions: For carrying out research in these fields (machine learning, vision, pattern recognition), what is your main or ideal programming language for rapid prototyping of ideas and testing algorithms contained in papers? For computer vision research work, can you list down the pros and cons of using the following languages? C++ (with opencv + gsl + svmlib + other libraries) vs Matlab (with all its toolboxes) vs python (with the imcomplete opencv bindings + numpy + scipy + matplotlib). Are there computer vision PhD/postgrad students here who are using only C++ (with all its availabe libraries including opencv) without even needing to resort to Matlab or python? In other words, given the current existing computer vision or machine learning libraries, is C++ alone sufficient for fast prototyping of ideas? If you're currently using Java or C# for your research, can you list down the reasons why they should be used and how they compare to other languages in terms of available libraries? What is the de facto vision/machine learning programming language and its associated libraries used in your research group? Thanks in advance. Edit: As suggested, I've opened the question to both academic and non-academic computer vision/machine learning/pattern recognition researchers and groups.

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  • HTTP Request from a PC to load the contents of a wap site

    - by cocoatoucher
    When I try to load a wap site with PHP HTTP request from my PC, host of the web site recognizes that I'm sending the request from a PC and redirects me to their actual web site and I can't load the wap site. Is there a way to behave like a mobile browser and prevent this redirection? Although an answer regarding any programming language is ok, a php specific answer will be better.

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