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  • How do I add ROW_NUMBER to a LINQ query or Entity?

    - by Whozumommy
    I'm stumped by this easy data problem. I'm using the Entity framework and have a database of products. My results page returns a paginated list of these products. Right now my results are ordered by the number of sales of each product, so my code looks like this: return Products.OrderByDescending(u => u.Sales.Count()); This returns an IQueryable dataset of my entities, sorted by the number of sales. I want my results page to show the rank of each product (in the dataset). My results should look like this: Page #1 1. Bananas 2. Apples 3. Coffee Page #2 4. Cookies 5. Ice Cream 6. Lettuce I'm expecting that I just want to add a column in my results using the SQL ROW_NUMBER variable...but I don't know how to add this column to my results datatable. My resulting page does contain a foreach loop, but since I'm using a paginated set I'm guessing using that number to fake a ranking number would NOT be the best approach. So my question is, how do I add a ROW_NUMBER column to my query results in this case?

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  • vb.net documentation and exception question

    - by dcp
    Let's say I have this sub in vb.net: ''' <summary> ''' Validates that <paramref name="value"/> is not <c>null</c>. ''' </summary> ''' ''' <param name="value">The object to validate.</param> ''' ''' <param name="name">The variable name of the object.</param> ''' ''' <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c>.</exception> Sub ValidateNotNull(ByVal value As Object, ByVal name As String) If value Is Nothing Then Throw New ArgumentNullException(name, String.Format("{0} cannot be null.", name)) End If End Sub My question is, is it proper to call this ValidateNotNull (which is what I would call it in C#) or should I stick with VB terminology and call it ValidateNotNothing instead? Also, in my exception, is it proper to say "cannot be null", or would it be better to say "cannot be Nothing"? I sort of like the way I have it, but since this is VB, maybe I should use Nothing. But since the exception itself is called ArgumentNullException, it feels weird to make the message say "cannot be Nothing". Anyway, I guess it's pretty nitkpicky, just wondered what you folks thought.

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  • Accessing XML file using JavaScript And ASP.net |VB code

    - by Bubba
    Am trying to read in data from an xml file but using javascript which is embedded into my asp.net|vb code. I am new to asp.net but coming from a programming background. so I declared the xml objects for the appropriate browsers, as well as the name of the local xml to read data from, I then start by appending the create the table tag and then append it to the div tag in hack5.aspx I declare the variable that will represent/ hold the xml returned data object. I then run a for loop , before creating a row tag and then appending it to the div tag in hack5.aspx I then create the a row tag and then appending it to the div tag in hack5.aspx | then create a TextNode which is passed to variable, then create a td and append to div . then lastly append the textnode to td this format is the same for creating another 13 td tags that are to hold the data. The main problem is when I run the script - I see nothing display on my screen . no errors are shown, but with your sample code runs smoothly. So the first file hack5.aspx is as follows: <%@ Page Language="VB" AutoEventWireup="false" CodeFile="hack5.aspx.vb" Inherits="_Default" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server"> <title>Diplaying MessageBox from ASP.NET</title> </head> <body> <form id="form1" runat="server"> <div id="showtime" > </div> </form> </body> </html> The next file hack5.aspx.vb is as follows: Partial Class _Default Inherits System.Web.UI.Page Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim scriptString as String = "<script language=JavaScript> if (window.XMLHttpRequest) " scriptString += " { " scriptString += " xhttp=new XMLHttpRequest(); " scriptString += " } " scriptString += " else " scriptString += " { " scriptString += " xhttp=new ActiveXObject('Microsoft.XMLHTTP'); " scriptString += " } " scriptString += " xhttp.open('GET','yes.xml',false); " scriptString += " xhttp.send(null);" scriptString += " xmlDoc= xhttp.responseXML; " scriptString += " var table1 = document.createElement('table'); " scriptString += " document.getElementById('showtime').appendChild(table1); " scriptString += " var x=xmlDoc.getElementsByTagName('Table'); " scriptString += " for (i=0;i<x.length;i++) " scriptString += " { " scriptString += " var assessment = document.createTextNode(x[i].getElementsByTagName('Assessment')[0].childNodes[0].nodeValue);" scriptString += " var row1 = document.createElement('tr'); " scriptString += " document.getElementById('showtime').appendChild(row1); " scriptString += " var column1 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column1); " scriptString += " column1.appendChild(assessment); " scriptString += " var Issue_Date = document.createTextNode(x[i].getElementsByTagName('Issue_Date')[0].childNodes[0].nodeValue);" scriptString += " var column2 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column2); " scriptString += " column2.appendChild(Issue_Date); " scriptString += " var Due_Date = document.createTextNode(x[i].getElementsByTagName('Due_Date')[0].childNodes[0].nodeValue);" scriptString += " var column3 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column3); " scriptString += " column3.appendChild(Due_Date); " scriptString += " var Interest = document.createTextNode(x[i].getElementsByTagName('Interest')[0].childNodes[0].nodeValue);" scriptString += " var column4 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column4); " scriptString += " column4.appendChild(Interest); " scriptString += " var Summary = document.createTextNode(x[i].getElementsByTagName('Summary')[0].childNodes[0].nodeValue);" scriptString += " var column5 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column5); " scriptString += " column5.appendChild(Summary);" scriptString += " var Amount_Due= document.createTextNode(x[i].getElementsByTagName('Amount_Due')[0].childNodes[0].nodeValue);" scriptString += " var column6 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column6); " scriptString += " column6.appendChild(Amount_Due);" scriptString += " var IEduty = document.createTextNode(x[i].getElementsByTagName('IEduty')[0].childNodes[0].nodeValue);" scriptString += " var column7 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column7); " scriptString += " column7.appendChild(IEduty);" scriptString += " var LEsurtax = document.createTextNode(x[i].getElementsByTagName('LEsurtax')[0].childNodes[0].nodeValue);" scriptString += " var column8 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column8); " scriptString += " column8.appendChild(LEsurtax);" scriptString += " var CEsurtax = document.createTextNode(x[i].getElementsByTagName('CEsurtax')[0].childNodes[0].nodeValue);" scriptString += " var column9 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column9); " scriptString += " column9.appendChild(CEsurtax);" scriptString += " var EXduty = document.createTextNode(x[i].getElementsByTagName('EXduty')[0].childNodes[0].nodeValue);" scriptString += " var column10 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column10); " scriptString += " column10.appendChild(EXduty);" scriptString += " var IMvat = document.createTextNode(x[i].getElementsByTagName('IMvat')[0].childNodes[0].nodeValue);" scriptString += " var column11 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column11); " scriptString += " column11.appendChild(IMvat);" scriptString += " var SYSfee = document.createTextNode(x[i].getElementsByTagName('SYSfee')[0].childNodes[0].nodeValue);" scriptString += " var column12 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column12); " scriptString += " column12.appendChild(SYSfee);" scriptString += " var AItax = document.createTextNode(x[i].getElementsByTagName('AItax')[0].childNodes[0].nodeValue);" scriptString += " var column13 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column13); " scriptString += " column13.appendChild(AItax);" scriptString += " var Cduty = document.createTextNode(x[i].getElementsByTagName('Cduty')[0].childNodes[0].nodeValue);" scriptString += " var column14 = document.createElement('td'); " scriptString += " document.getElementById('showtime').appendChild(column14); " scriptString += " column14.appendChild(Cduty);" scriptString += " } " scriptString += " <" scriptString += "/" scriptString += "script>" If(Not ClientScript.IsStartupScriptRegistered("clientScript")) ClientScript.RegisterClientScriptBlock(Me.GetType(),"clientScript", scriptString) End If End Sub End Class And finally the xml file is as follows: <?xml version="1.0" encoding="utf-8" ?> <DataSet xmlns="http://tempuri.org/"> <xs:schema id="NewDataSet" xmlns="" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata"> <xs:element name="NewDataSet" msdata:IsDataSet="true" msdata:UseCurrentLocale="true"> <xs:complexType> <xs:choice minOccurs="0" maxOccurs="unbounded"> <xs:element name="Table"> <xs:complexType> <xs:sequence> <xs:element name="UserName" type="xs:string" minOccurs="0" /> <xs:element name="Password" type="xs:string" minOccurs="0" /> <xs:element name="UserLevel" type="xs:string" minOccurs="0" /> <xs:element name="FName" type="xs:string" minOccurs="0" /> <xs:element name="LName" type="xs:string" minOccurs="0" /> <xs:element name="Branch" type="xs:string" minOccurs="0" /> <xs:element name="Department" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> </xs:choice> </xs:complexType> </xs:element> </xs:schema> <diffgr:diffgram xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" xmlns:diffgr="urn:schemas-microsoft-com:xml-diffgram-v1"> <NewDataSet xmlns=""> <Table diffgr:id="Table1" msdata:rowOrder="0"> <Assessment>CHR/A157/2009</Assessment> <Issue_Date>20/10/2009</Issue_Date> <Due_Date>01/11/2009</Due_Date> <Interest>2.00</Interest> <Summary>BENTLEY 2009</Summary> <Amount_Due>28000000.00</Amount_Due> <IEduty>3000000.00</IEduty> <LEsurtax>4000000.00</LEsurtax> <CEsurtax>5000000.00</CEsurtax> <EXduty>0.00</EXduty> <IMvat>5000000.00</IMvat> <SYSfee>8000000.00</SYSfee> <AItax>2000000.00</AItax> <Cduty>1000000.00</Cduty> </Table> <Table diffgr:id="Table1" msdata:rowOrder="1"> <Assessment>CHR/A167/2009</Assessment> <Issue_Date>20/10/2009</Issue_Date> <Due_Date>01/11/2009</Due_Date> <Interest>2.00</Interest> <Summary>BENTLEY 2009</Summary> <Amount_Due>24000000.00</Amount_Due> <IEduty>3000000.00</IEduty> <LEsurtax>4000000.00</LEsurtax> <CEsurtax>5000000.00</CEsurtax> <EXduty>0.00</EXduty> <IMvat>1000000.00</IMvat> <SYSfee>8000000.00</SYSfee> <AItax>2000000.00</AItax> <Cduty>1000000.00</Cduty> </Table> <Table diffgr:id="Table1" msdata:rowOrder="2"> <Assessment>CHR/A196/2009</Assessment> <Issue_Date>11/11/2009</Issue_Date> <Due_Date>21/11/2009</Due_Date> <Interest>2.00</Interest> <Summary>BENTLEY 2009</Summary> <Amount_Due>20000000.00</Amount_Due> <IEduty>3000000.00</IEduty> <LEsurtax>4000000.00</LEsurtax> <CEsurtax>5000000.00</CEsurtax> <EXduty>0.00</EXduty> <IMvat>1000000.00</IMvat> <SYSfee>4000000.00</SYSfee> <AItax>2000000.00</AItax> <Cduty>1000000.00</Cduty> </Table> </NewDataSet> </diffgr:diffgram> </DataSet>

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  • Predefined column names in SQL Server pivot table

    - by Marcos Buarque
    Hi, the other day I opened a topic here in StackOverflow (stackoverflow.com/questions/4663698/how-can-i-display-a-consolidated-version-of-my-sql-server-table). At that time I needed help on how to show data on a pivot table. From the help I got here in the forum, my research led me to this page about dynamic SQL: www.sommarskog.se/dynamic_sql.html. And then it led me to this awesome SQL script by Itzik Ben-Gan that will create a stored procedure that outputs a pivot table exactly the way I want: sommarskog.se/pivot_sp.sp. Well, almost. I need one change in this stored procedure. Instead of having dynamic column names pulled from the @on_cols variable in the SPROC, I need the output table to hold generic column names in simple ASC order. Could be, for example, col1, col2, col3, col4 ... The dynamic column names are a problem for me. So I need them named by their index in the order they appear. I have tried all sorts of things changing this great SQL script, but it won't work. I did not paste the code from the author because it is too long, but the link above will get us there. Any help appreciated. Thank you very much

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  • Returning searched results in an array in Java without ArrayList

    - by Crystal
    I started down this path of implementing a simple search in an array for a hw assignment without knowing we could use ArrayList. I realized it had some bugs in it and figured I'd still try to know what my bug is before using ArrayList. I basically have a class where I can add, remove, or search from an array. public class AcmeLoanManager { public void addLoan(Loan h) { int loanId = h.getLoanId(); loanArray[loanId - 1] = h; } public Loan[] getAllLoans() { return loanArray; } public Loan[] findLoans(Person p) { //Loan[] searchedLoanArray = new Loan[10]; // create new array to hold searched values searchedLoanArray = this.getAllLoans(); // fill new array with all values // Looks through only valid array values, and if Person p does not match using Person.equals() // sets that value to null. for (int i = 0; i < searchedLoanArray.length; i++) { if (searchedLoanArray[i] != null) { if (!(searchedLoanArray[i].getClient().equals(p))) { searchedLoanArray[i] = null; } } } return searchedLoanArray; } public void removeLoan(int loanId) { loanArray[loanId - 1] = null; } private Loan[] loanArray = new Loan[10]; private Loan[] searchedLoanArray = new Loan[10]; // separate array to hold values returned from search } When testing this, I thought it worked, but I think I am overwriting my member variable after I do a search. I initially thought that I could create a new Loan[] in the method and return that, but that didn't seem to work. Then I thought I could have two arrays. One that would not change, and the other just for the searched values. But I think I am not understanding something, like shallow vs deep copying???....

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  • Allowing Google to bypass CAPTCHA verification - sensible or not?

    - by edanfalls
    My web site has a database lookup; filling out a CAPTCHA gives you 5 minutes of lookup time. There is also some custom code to detect any automated scripts. I do this as I don't want someone data mining my site. The problem is that Google does not see the lookup results when it crawls my site. If someone is searching for a string that is present in the result of a lookup, I would like them to find this page by Googling it. The obvious solution to me is to use the PHP variable $_SERVER['HTTP_USER_AGENT'] to bypass the CAPTCHA and custom security code for the Google bots. My question is whether this is sensible or not. People could then use Google's cache to view the lookup results without having to fill out the CAPTCHA, but would Google's own script detection methods prevent them from data mining these pages? Or would there be some way for people to make $_SERVER['HTTP_USER_AGENT'] appear as Google to bypass the security measures? Thanks in advance.

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  • How to convert struct to char array in C

    - by falcojr
    I'm trying to convert a struct to a char array to send over the network. However, I get some weird output from the char array when I do. #include <stdio.h> struct x { int x; } __attribute__((packed)); int main() { struct x a; a.x=127; char *b = (char *)&a; int i; for (i=0; i<4; i++) printf("%02x ", b[i]); printf("\n"); for (i=0; i<4; i++) printf("%d ", b[i]); printf("\n"); return 0; } Here is the output for various values of a.x (on an X86 using gcc): 127: 7f 00 00 00 127 0 0 0 128: ffffff80 00 00 00 -128 0 0 0 255: ffffffff 00 00 00 -1 0 0 0 256: 00 01 00 00 0 1 0 0 I understand the values for 127 and 256, but why do the numbers change when going to 128? Why wouldn't it just be: 80 00 00 00 128 0 0 0 Am I forgetting to do something in the conversion process or am I forgetting something about integer representation? *Note: This is just a small test program. In a real program I have more in the struct, better variable names, and I convert to little-endian. *Edit: formatting

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  • What does flushing thread local memory to global memory mean?

    - by Jack Griffith
    Hi, I am aware that the purpose of volatile variables in Java is that writes to such variables are immediately visible to other threads. I am also aware that one of the effects of a synchronized block is to flush thread-local memory to global memory. I have never fully understood the references to 'thread-local' memory in this context. I understand that data which only exists on the stack is thread-local, but when talking about objects on the heap my understanding becomes hazy. I was hoping that to get comments on the following points: When executing on a machine with multiple processors, does flushing thread-local memory simply refer to the flushing of the CPU cache into RAM? When executing on a uniprocessor machine, does this mean anything at all? If it is possible for the heap to have the same variable at two different memory locations (each accessed by a different thread), under what circumstances would this arise? What implications does this have to garbage collection? How aggressively do VMs do this kind of thing? Overall, I think am trying to understand whether thread-local means memory that is physically accessible by only one CPU or if there is logical thread-local heap partitioning done by the VM? Any links to presentations or documentation would be immensely helpful. I have spent time researching this, and although I have found lots of nice literature, I haven't been able to satisfy my curiosity regarding the different situations & definitions of thread-local memory. Thanks very much.

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  • How do I apply a "template" or "skeleton" of code in C# here?

    - by Scott Stafford
    In my business layer, I need many, many methods that follow the pattern: public BusinessClass PropertyName { get { if (this.m_LocallyCachedValue == null) { if (this.Record == null) { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.PropertyId); } else { this.m_LocallyCachedValue = new BusinessClass( this.Database, this.Record.ForeignKeyName); } } return this.m_LocallyCachedValue; } } I am still learning C#, and I'm trying to figure out the best way to write this pattern once and add methods to each business layer class that follow this pattern with the proper types and variable names substituted. BusinessClass is a typename that must be substituted, and PropertyName, PropertyId, ForeignKeyName, and m_LocallyCachedValue are all variables that should be substituted for. Are attributes usable here? Do I need reflection? How do I write the skeleton I provided in one place and then just write a line or two containing the substitution parameters and get the pattern to propagate itself? EDIT: Modified my misleading title -- I am hoping to find a solution that doesn't involve code generation or copy/paste techniques, and rather to be able to write the skeleton of the code once in a base class in some form and have it be "instantiated" into lots of subclasses as the accessor for various properties. EDIT: Here is my solution, as suggested but left unimplemented by the chosen answerer. // I'll write many of these... public BusinessClass PropertyName { get { return GetSingleRelation(ref this.m_LocallyCachedValue, this.PropertyId, "ForeignKeyName"); } } // That all call this. public TBusinessClass GetSingleRelation<TBusinessClass>( ref TBusinessClass cachedField, int fieldId, string contextFieldName) { if (cachedField == null) { if (this.Record == null) { ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), typeof(int) }); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, fieldId }); } else { var obj = this.Record.GetType().GetProperty(objName).GetValue( this.Record, null); ConstructorInfo ci = typeof(TBusinessClass).GetConstructor( new Type[] { this.Database.GetType(), obj.GetType()}); cachedField = (TBusinessClass)ci.Invoke( new object[] { this.Database, obj }); } } return cachedField; }

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  • Optional Member Objects

    - by David Relihan
    Okay, so you have a load of methods sprinkled around your systems main class. So you do the right thing and refactor by creating a new class and perform move method(s) into a new class. The new class has a single responsibility and all is right with the world again: class Feature { public: Feature(){}; void doSomething(); void doSomething1(); void doSomething2(); }; So now your original class has a member variable of type object: Feature _feature; Which you will call in the main class. Now if you do this many times, you will have many member-objects in your main class. Now these features may or not be required based on configuration so in a way it's costly having all these objects that may or not be needed. Can anyone suggest a way of improving this? At the moment I plan to test in the newly created class if the feature is enabled - so the when a call is made to method I will return if it is not enabled. I could have a pointer to the object and then only call new if feature is enabled - but this means I will have to test before I call a method on it which would be potentially dangerous and not very readable. Would having an auto_ptr to the object improve things: auto_ptr<Feature> feature; Or am I still paying the cost of object invokation even though the object may\or may not be required. BTW - I don't think this is premeature optimisation - I just want to consider the possibilites.

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  • Editing a .class file directly, playing around with opcodes

    - by echox
    Hi, today I just tried to play a little bit around with the opcodes in compiled java class file. After inserting iinc 1,1 the java virtual machine responds with: Exception in thread "main" java.lang.ClassFormatError: Truncated class file at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) at java.lang.ClassLoader.defineClass(ClassLoader.java:616) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) Could not find the main class: Test. Program will exit. This is my example source code: public class Test { public static void main(String[] args) { int i = 5; i++; i++; i++; System.out.println("Number: " + i + "\n"); } } The opcode for an increment is 0x84 + 2 bytes for operands. There's only one section in the resulting class file, which contains 0x84: [..] 8401 0184 0101 8401 01[..] So I would translate this as: iinc 1,1 iinc 1,1 iinc 1,1 corresponding to my i++; i++; i++; I then tried to append just 840101 to increment the variable once more, but that didn't work and resulted in the ClassFormatError. Is there anything like a checksum for the class file? I looked up the format of a classfile in http://java.sun.com/docs/books/jvms/second_edition/html/ClassFile.doc.html but could not find anything which points out to some kind of bytes_of_classfile or something. I also don't understand why the error is "Truncated Class File", because I did append something :-) I know its not a good idea to edit class files directly, but I'm just interested on the VM internals here.

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  • javascript - How to pass an argument in a function call?

    - by Fernando SBS
    function rp_marcadesmarcaFarm(valor) { FM_log(3, "marcadesmarcaFarm called = "+valor); for (i = 0; i < farmList.length; i++) { var arr = farmList[i].split("|"); var xy = arr[0].split(","); var fvillageId = xy2id(parseInt(xy[0]), parseInt(xy[1])); GM_setValue("farmAtivada_"+suffixLocal+fvillageId, valor); GM_setValue("farmAtivada_"+suffixLocal+i, valor); }; reloadFarmTable(); }; function createLinkButton(text, title, jsFunction, value) { var button = dom.cn("a"); button.href = "javascript:void(0)"; button.innerHTML = text; button.title = title; if (jsFunction != null) { button.addEventListener('click', jsFunction, false); } return button; } createLinkButton("X", T('CHECKFARM_M'), rp_marcadesmarcaFarm(true)); apparently the last argument (rp_marcadesmarcaFarm(true)) when invoking the createLinkButton is not working. If I change to: createLinkButton("X", T('CHECKFARM_M'), rp_marcadesmarcaFarm); it works. So how can I pass the (true) variable to the third argument of createLinkButton?

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  • error detection/correction/recovery in serial protocols

    - by Jason S
    I have some designing to do for a serial protocol and am running into some questions that I figure must have been considered elsewhere. So I'm wondering if there are some recommendations for best practices in designing serial protocols. (Please either state a fact that is easily verifiable, or cite a reputable source if you make a claim.) General recommendations for websites/books are also welcome. In particular I have to deal with issues like parsing a stream of bytes into packets verifying a packet is correct (easy with a CRC, for instance) identifying reasonable types of errors that can occur (e.g. in a point-to-point serial stream, sporadic single bit errors, and dropped series of bytes, are both likely, but extra phantom bytes are unlikely; whereas with a record stored in flash memory or on a disk drive the types of errors that predominate are different) error correction or recovery (if I detect an error in a packet, can I correct it? If not, can I resync to the boundary of the next packet?) how to make variable-length packets robust to error correction / recovery. Any suggestions?

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  • What is a data structure for quickly finding non-empty intersections of a list of sets?

    - by Andrey Fedorov
    I have a set of N items, which are sets of integers, let's assume it's ordered and call it I[1..N]. Given a candidate set, I need to find the subset of I which have non-empty intersections with the candidate. So, for example, if: I = [{1,2}, {2,3}, {4,5}] I'm looking to define valid_items(items, candidate), such that: valid_items(I, {1}) == {1} valid_items(I, {2}) == {1, 2} valid_items(I, {3,4}) == {2, 3} I'm trying to optimize for one given set I and a variable candidate sets. Currently I am doing this by caching items_containing[n] = {the sets which contain n}. In the above example, that would be: items_containing = [{}, {1}, {1,2}, {2}, {3}, {3}] That is, 0 is contained in no items, 1 is contained in item 1, 2 is contained in itmes 1 and 2, 2 is contained in item 2, 3 is contained in item 2, and 4 and 5 are contained in item 3. That way, I can define valid_items(I, candidate) = union(items_containing[n] for n in candidate). Is there any more efficient data structure (of a reasonable size) for caching the result of this union? The obvious example of space 2^N is not acceptable, but N or N*log(N) would be.

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  • MEF GetExports<T, TMetaDataView> returning nothing with AllowMultiple = True

    - by sohum
    I don't understand MEF very well, so hopefully this is a simple fix of how I think it works. I'm trying to use MEF to get some information about a class and how it should be used. I'm using the Metadata options to try to achieve this. My interfaces and attribute looks like this: public interface IMyInterface { } public interface IMyInterfaceInfo { Type SomeProperty1 { get; } double SomeProperty2 { get; } string SomeProperty3 { get; } } [MetadataAttribute] [AttributeUsage(AttributeTargets.Class, AllowMultiple = true)] public class ExportMyInterfaceAttribute : ExportAttribute, IMyInterfaceInfo { public ExportMyInterfaceAttribute(Type someProperty1, double someProperty2, string someProperty3) : base(typeof(IMyInterface)) { SomeProperty1 = someProperty1; SomeProperty2 = someProperty2; SomeProperty3 = someProperty3; } public Type SomeProperty1 { get; set; } public double SomeProperty2 { get; set; } public string SomeProperty3 { get; set; } } The class that is decorated with the attribute looks like this: [ExportMyInterface(typeof(string), 0.1, "whoo data!")] [ExportMyInterface(typeof(int), 0.4, "asdfasdf!!")] public class DecoratedClass : IMyInterface { } The method that is trying to use the import looks like this: private void SomeFunction() { // CompositionContainer is an instance of CompositionContainer var myExports = CompositionContainer.GetExports<IMyInterface, IMyInterfaceInfo>(); } In my case myExports is always empty. In my CompositionContainer, I have a Part in my catalog that has two ExportDefinitions, both with the following ContractName: "MyNamespace.IMyInterface". The Metadata is also loaded correctly per my exports. If I remove the AllowMultiple setter and only include one exported attribute, the myExports variable now has the single export with its loaded metadata. What am I doing wrong?

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  • How to output KML by GAE

    - by Niklas R
    Hi I use KML for a google map where entities have a geopt.db coordinate and soft memory limit was exceeded with 213.465 MB after servicing 1 requests total. The log says /list.kml 200 13130ms 10211cpu_ms 4238api_cpu_ms The file list.kml which outputs about 455,7 KB is a template as follows <?xml version="1.0" encoding="UTF-8"?><kml xmlns="http:// www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2" xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http:// www.w3.org/2005/Atom"> <Document>{% for a in list %} <Placemark> <name> </name> <description> <![CDATA[<a href="http://{{host}}/{{a.key.id}}"> {{ a.title }} </a> <br/>{{a.text}}]]> </description> <Style> <IconStyle> <Icon> <href> http://www.google.com/intl/en_us/mapfiles/ms/icons/green-dot.png </href> </Icon> </IconStyle> </Style> <Point> <coordinates> {{a.geopt.lon|floatformat:2}},{{a.geopt.lat|floatformat:2}} </coordinates> </Point> </Placemark> {% endfor %} </Document> </kml> Is there a memory leak in the template or the python that passes the list variable? Can I improve using other template engine or other framework than default? Is kmz compression a good idea in this case? Thanks in advance for any suggestion where or how to change the code.

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  • Is there any Java Decompiler that can correctly decompile calls to overloaded methods?

    - by mihi
    Consider this (IMHO simple) example: public class DecompilerTest { public static void main(String[] args) { Object s1 = "The", s2 = "answer"; doPrint((Object) "You should know:"); for (int i = 0; i < 2; i++) { doPrint(s1); doPrint(s2); s1 = "is"; s2 = new Integer(42); } System.out.println(); } private static void doPrint(String s1) { System.out.print("Wrong!"); } private static void doPrint(Object s1) { System.out.print(s1 + " "); } } Compile it with source/target level 1.1 without debug information (i.e. no local variable information should be present) and try to decompile it. I tried Jad, JD-GUI and Fernflower, and all of them got at least one of the call wrong (i. e. the program printed "Wrong!" at least once) Is there really no java decompiler that can infer the right casts so that it will not call the wrong overload?

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  • Reading Code - helpful visualizers and browser tools

    - by wishi_
    Hi! I find myself reading 10 times more code than writing. My IDEs all are optimized to make me edit code - with completion, code assist, outlines etc. However if I'm checking out a completely new project: getting into the application's logics isn't optimized with these IDE features. Because I cannot extend what I don't fully understand. If you for example check out a relatively new project, frama-c, you realize that it has got plugins that are helpful to gain insight into "unfamiliar code": http://frama-c.com/plugins.html - However of course the project has a different scope. What I'm fully aware of. I'm looking for something that does helpful things for code-reading. Like: providing a graph, - reverse engineering UML e g., showing variable scopes showing which parts are affected by attempted modifications visualizing data-flow semantics showing tag-lists of heavily utilized functions ... My hope is that something like that exists. - That there're some Eclipse plugins I don't know or that there's a code-browser that has some of these features?

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  • How to I pass parameters to Ruby/Python scripts from inside PHP?

    - by Roger
    Hi, everybody. I need to turn HTML into equivalent Markdown-structured text. From what I could discover, I have only two good choices: Python: Aaron Swartz's html2text.py Ruby: Singpolyma's html2markdown.rb As I am programming in PHP, I need to pass the HTML code, call the Ruby/Python Script and receive the output back. I started creating a simple test just to know if my server was configured to run both languages. PHP code: echo exec('./hi.rb'); Ruby code: #!/usr/bin/ruby puts "Hello World!" It worked fine and I am ready to go to the next step. Unfortunately, all I know is that the function is Ruby works like this: HTML2Markdown.new('<h1>HTMLcode</h1>').to_s I don't know how to make PHP pass the string (with the HTML code) to Ruby nor how to make the ruby script receive the variable and pass it back to PHP (after have parsed it into Markdown). Believe it or not: I know less of Python. A folk made a similar question here ("how to call ruby script from php?") but with no practical information to my case. Any help would be a joy - thanks. Rogério Madureira. atipico.com.br

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  • How to set up django-admin.py on windos vista?

    - by shin
    I manage to install Django after some struggles by using setup.py install on Windows Vista Now I tried to use django-admin.py but it is not working. According to this document, http://docs.djangoproject.com/en/dev/ref/django-admin/ The django-admin.py script should be on your system path if you installed Django via its setup.py utility. If it’s not on your path, ... For Windows users, who do not have symlinking functionality available, you can copy django-admin.py to a location on your existing path or edit the PATH settings (under Settings - Control Panel - System - Advanced - Environment...) to point to its installed location. I checked ComputerpropertiesEnvironment Variables, but path to django-admin.py is not in anywhere. So I added C:\Python25\Lib\site-packages\django\bin which is the folder of django-admin.py in User variables for shin Variable PATH, Value C:\Program Files\Google\google_appengine\;C:\Python25\Lib\site-packages\django\bin\ Am I supposed to add to System variables?? But it still does not work. Could anyone tell me how to add the Path in Environment Variables please? Thanks in advance.

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  • How do I DYNAMICALLY cast in C# and return for a property

    - by ken-forslund
    I've already read threads on the topic, but can't find a solution that fits. I'm working on a drop-down list that takes an enum and uses that to populate itself. i found a VB.NET one. During the porting process, I discovered that it uses DirectCast() to set the type as it returns the SelectedValue. See the original VB here: http://jeffhandley.com/archive/2008/01/27/enum-list-dropdown-control.aspx the gist is, the control has Type _enumType; //gets set when the datasource is set and is the type of the specific enum The SelectedValue property kind of looks like (remember, it doesn't work): public Enum SelectedValue //Shadows Property { get { // Get the value from the request to allow for disabled viewstate string RequestValue = this.Page.Request.Params[this.UniqueID]; return Enum.Parse(_enumType, RequestValue, true) as _enumType; } set { base.SelectedValue = value.ToString(); } } Now this touches on a core point that I think was missed in the other discussions. In darn near every example, folks argued that DirectCast wasn't needed, because in every example, they statically defined the type. That's not the case here. As the programmer of the control, I don't know the type. Therefore, I can't cast it. Additionally, the following examples of lines won't compile because c# casting doesn't accept a variable. Whereas VB's CType and DirectCast can accept Type T as a function parameter: return Enum.Parse(_enumType, RequestValue, true); or return Enum.Parse(_enumType, RequestValue, true) as _enumType; or return (_enumType)Enum.Parse(_enumType, RequestValue, true) ; or return Convert.ChangeType(Enum.Parse(_enumType, RequestValue, true), _enumType); or return CastTo<_enumType>(Enum.Parse(_enumType, RequestValue, true)); So, any ideas on a solution? What's the .NET 3.5 best way to resolve this?

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  • How to load JPG file into NSBitmapImageRep?

    - by Adam
    Objective-C / Cocoa: I need to load the image from a JPG file into a two dimensional array so that I can access each pixel. I am trying (unsuccessfully) to load the image into a NSBitmapImageRep. I have tried several variations on the following two lines of code: NSString *filePath = [NSString stringWithFormat: @"%@%@",@"/Users/adam/Documents/phoneimages/", [outLabel stringValue]]; //this coming from a window control NSImageRep *controlBitmap = [[NSImageRep alloc] imageRepWithContentsOfFile:filePath]; With the code shown, I get a runtime error: -[NSImageRep imageRepWithContentsOfFile:]: unrecognized selector sent to instance 0x100147070. I have tried replacing the second line of code with: NSImage *controlImage = [[NSImage alloc] initWithContentsOfFile:filePath]; NSBitmapImageRep *controlBitmap = [[NSBitmapImageRep alloc] initWithData:controlImage]; But this yields a compiler error 'incompatible type' saying that initWithData wants a NSData variable not an NSImage. I have also tried various other ways to get this done, but all are unsuccessful either due to compiler or runtime error. Can someone help me with this? I will eventually need to load some PNG files in the same way (so it would be nice to have a consistent technique for both). And if you know of an easier / simpler way to accomplish what I am trying to do (i.e., get the images into a two-dimensional array), rather than using NSBitmapImageRep, then please let me know! And by the way, I know the path is valid (confirmed with fileExistsAtPath) -- and the filename in outLabel is a file with .jpg extension. Thanks for any help!

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  • NSURLConnection and empty post variables

    - by SooDesuNe
    I'm at my wits end with this one, because I've used very similar code in the past, and it worked just fine. The following code results in empty $_POST variables on the server. I verified this with: file_put_contents('log_file_name', "log: ".$word, FILE_APPEND); the only contents of log_file_name was "log: " I then verified the PHP with a simple HTML form. It performed as expected. The Objective-C: NSString *word = "this_word_gets_lost"; NSString *myRequestString = [NSString stringWithFormat:@"word=%@", word]; [self postAsynchronousPHPRequest:myRequestString toPage:@"http://www.mysite.com/mypage.php" delegate:nil]; } -(void) postAsynchronousPHPRequest:(NSString*)request toPage:(NSString*)URL delegate:(id)delegate{ NSData *requestData = [ NSData dataWithBytes: [ request UTF8String ] length: [ request length ] ]; NSMutableURLRequest *URLrequest = [ [ NSMutableURLRequest alloc ] initWithURL: [ NSURL URLWithString: URL ] ]; [ URLrequest setHTTPMethod: @"POST" ]; [ URLrequest setHTTPBody: requestData ]; [ NSURLConnection connectionWithRequest:URLrequest delegate:delegate]; [URLrequest release]; } The PHP: $word = $_POST['word']; file_put_contents('log_file_name', "log: ".$word, FILE_APPEND); What am I doing wrong in the Objective-C that would cause the $_POST variable to be empty on the server?

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  • Help with java executors: wait for task termination.

    - by Raffo
    I need to submit a number of task and then wait for them until all results are available. Each of them adds a String to a Vector (that is synchronized by default). Then I need to start a new task for each result in the Vector but I need to do this only when all the previous tasks have stopped doing their job. I want to use Java Executor, in particular I tried using Executors.newFixedThreadPool(100) in order to use a fixed number of thread (I have a variable number of task that can be 10 or 500) but I'm new with executors and I don't know how to wait for task termination. This is something like a pseudocode of what my program needs to do: EecutorService e = Executors.newFixedThreadPool(100); while(true){ /*do something*/ for(...){ <start task> } <wait for all task termination> for each String in result{ <start task> } <wait for all task termination> } I can't do a e.shutdown because I'm in a while(true) and I need to reuse the executorService... Can you help me? Can you suggest me a guide/book about java executors??

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  • use php to parse json data posted from another php file

    - by akshay.is.gr8
    my web hosting has blocked the outward traffic so i am using a free web hosting to read data and post it to my server but the problem is that my php file receives data in the $_REQUEST variable but is not able to parse it. post.php function postCon($pCon){ //echo $pCon; $ch = curl_init('http://localhost/rss/recv.php'); curl_setopt ($ch, CURLOPT_POST, 1); curl_setopt ($ch, CURLOPT_POSTFIELDS, "data=$pCon"); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); $d=curl_exec ($ch); echo $d."<br />"; curl_close ($ch); } recv.php <?php if(!json_decode($_REQUEST['data'])) echo "json error"; echo "<pre>"; print_r($data); echo "</pre>"; ?> every time it gives json error. but echo $_REQUEST['data'] gives the correct json data. plz help.

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