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• JAVA - Strange problem (probably thread problem) with JTable & Model

  - by Stefanos Kargas

  I am using 2 Tables (JTable) with their DefaultTableModels. The first table is already populated. The second table is populated for each row of the first table (using an SQL Query). My purpose is to export every line of the first table with it's respective lines of the second in an Excel File. I am doing it with a for (for each line of 1st table), in which I write a line of the 1st table in the Excel File, then I populate the 2nd table (for this line of 1st Table), I get every line from the Table (from it's Model actually) and put it in the Excel File under the current line of 1st table. This means that if I have n lines in first table I will clear and populate again the second table n times. All this code is called in a seperate thread. THE PROBLEM IS: Everything works perfectly fine ecxept that I am getting some exceptions. The strange thing is that I'm not getting anything false in my result. The Excel file is perfect. Some of the lines of the exceptions are: Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0 = 0 at java.util.Vector.elementAt(Vector.java:427) at javax.swing.table.DefaultTableModel.getValueAt(DefaultTableModel.java:632) at javax.swing.JComponent.paint(JComponent.java:1017) at javax.swing.RepaintManager.paint(RepaintManager.java:1220) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:803) I am assuming that the problem lies in the fact that the second table needs some more time to be populated before I try to get any data from it. That's why I see RepaintManager and paintDirtyRegions in my exceptions. Another thing I did is that I ran my program in debug mode and I put a breakpoint after each population of the 2nd table. Then I pressed F5 to continue for each population of 2nd table and no exception appeared. The program came to it's end without any exceptions. This is another important fact that tells me that maybe in this case I gave the table enough time to be populated. Of course you will ask me: If your program works fine, why do you care about the exceptions? I care for avoiding any future problems and I care to have a better understanding of Java and Java GUI and threads. Why do you depend on a GUI component (and it's model) to get your information and why don't you recreate the resultset that populates your tables using an SQL Query and get your info from the resultset? That would be the best and the right way. The fact is that I have the tables code ready and it was easier for me to just get the info from them. But the right way would be to get everything direct from database. Anyway what I did brought out my question, and answering it would help me understand more things about java. So I posted it.

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• Why is javac 1.5 running so slowly compared with the Eclipse compiler?

  - by Simon Nickerson

  I have a Java Maven project with about 800 source files (some generated by javacc/JTB) which is taking a good 25 minutes to compile with javac. When I changed my pom.xml over to use the Eclipse compiler, it takes about 30 seconds to compile. Any suggestions as to why javac (1.5) is running so slowly? (I don't want to switch over to the Eclipse compiler permanently, as the plugin for Maven seems more than a little buggy.) I have a test case which easily reproduces the problem. The following code generates a number of source files in the default package. If you try to compile ImplementingClass.java with javac, it will seem to pause for an inordinately long time. import java.io.File; import java.io.FileNotFoundException; import java.io.PrintStream; public class CodeGenerator { private final static String PATH = System.getProperty("java.io.tmpdir"); private final static int NUM_TYPES = 1000; public static void main(String[] args) throws FileNotFoundException { PrintStream interfacePs = new PrintStream(PATH + File.separator + "Interface.java"); PrintStream abstractClassPs = new PrintStream(PATH + File.separator + "AbstractClass.java"); PrintStream implementingClassPs = new PrintStream(PATH + File.separator + "ImplementingClass.java"); interfacePs.println("public interface Interface<T> {"); abstractClassPs.println("public abstract class AbstractClass<T> implements Interface<T> {"); implementingClassPs.println("public class ImplementingClass extends AbstractClass<Object> {"); for (int i=0; i<NUM_TYPES; i++) { String nodeName = "Node" + i; PrintStream nodePs = new PrintStream(PATH + File.separator + nodeName + ".java"); nodePs.printf("public class %s { }\n", nodeName); nodePs.close(); interfacePs.printf("void visit(%s node, T obj);%n", nodeName); abstractClassPs.printf("public void visit(%s node, T obj) { System.out.println(obj.toString()); }%n", nodeName); } interfacePs.println("}"); abstractClassPs.println("}"); implementingClassPs.println("}"); interfacePs.close(); abstractClassPs.close(); implementingClassPs.close(); } }

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• Specializating a template function that takes a universal reference parameter

  - by David Stone

  How do I specialize a template function that takes a universal reference parameter? foo.hpp: template<typename T> void foo(T && t) // universal reference parameter foo.cpp template<> void foo<Class>(Class && class) { // do something complicated } Here, Class is no longer a deduced type and thus is Class exactly; it cannot possibly be Class &, so reference collapsing rules will not help me here. I could perhaps create another specialization that takes a Class & parameter (I'm not sure), but that implies duplicating all of the code contained within foo for every possible combination of rvalue / lvalue references for all parameters, which is what universal references are supposed to avoid. Is there some way to accomplish this? To be more specific about my problem in case there is a better way to solve it: I have a program that can connect to multiple game servers, and each server, for the most part, calls everything by the same name. However, they have slightly different versions for a few things. There are a few different categories that these things can be: a move, an item, etc. I have written a generic sort of "move string to move enum" set of functions for internal code to call, and my server interface code has similar functions. However, some servers have their own internal ID that they communicate with, some use strings, and some use both in different situations. Now what I want to do is make this a little more generic. I want to be able to call something like ServerNamespace::server_cast<Destination>(source). This would allow me to cast from a Move to a std::string or ServerMoveID. Internally, I may need to make a copy (or move from) because some servers require that I keep a history of messages sent. Universal references seem to be the obvious solution to this problem. The header file I'm thinking of right now would expose simply this: namespace ServerNamespace { template<typename Destination, typename Source> Destination server_cast(Source && source); } And the implementation file would define all legal conversions as template specializations.

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• Why does my Spring Controller direct me to the wrong page?

  - by kc2001

  I am writing my first Spring 3.0.5 MVC app and am confused about why my controller mappings aren't doing what I expect. I have a VerifyPasswordController that is called after a user tries to log in by entering his name and password. // Called upon clicking "submit" from /login @RequestMapping(value = "/verifyPassword", method = RequestMethod.POST) @ModelAttribute("user") public String verifyPassword(User user, BindingResult result) { String email = user.getEmail(); String nextPage = CHOOSE_OPERATION_PAGE; // success case if (result.hasErrors()) { nextPage = LOGIN_PAGE; } else if (!passwordMatches(email, user.getPassword())) { nextPage = LOGIN_FAILURE_PAGE; } else { // success } return nextPage; } I can verify in the debugger that this method is being called, but afterwards, the verifyPassword page is displayed rather than the chooseOperation page. The console output of WebLogic seems to show that my mapping are correct: INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation.*] onto handler 'chooseOperationController' INFO : org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping - Mapped URL path [/chooseOperation/] onto handler 'chooseOperationController' Here is the ChooseOperationController: @Controller @SessionAttributes("leaveRequestForm") public class ChooseOperationController implements PageIfc, AttributeIfc { @RequestMapping(value = "/chooseOperation") @ModelAttribute("leaveRequestForm") public LeaveRequest setUpLeaveRequestForm( @RequestParam(NAME_ATTRIBUTE) String name) { LeaveRequest form = populateFormFromDatabase(name); return form; } // helper methods omited } I welcome any advice, particularly "generic" techniques for debugging such mapping problems. BTW, I've also tried to "redirect" to the desired page, but got the same result. servlet-context.xml: <?xml version="1.0" encoding="UTF-8"?> <beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation=" http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"> <!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure --> <!-- Enables the Spring MVC @Controller programming model --> <annotation-driven /> <!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory --> <resources mapping="/resources/**" location="/resources/" /> <!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory --> <beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <beans:property name="prefix" value="/WEB-INF/views/" /> <beans:property name="suffix" value=".jsp" /> </beans:bean> <context:component-scan base-package="com.engilitycorp.leavetracker" /> <beans:bean id="leaveRequestForm" class="com.engilitycorp.leavetracker.model.LeaveRequest" /> </beans:beans> The constants: String LOGIN_FAILURE_PAGE = "loginFailure"; String LOGIN_PAGE = "login"; String CHOOSE_OPERATION_PAGE = "chooseOperation";

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• Emulating Button Press Using Kinect/SimpleOpenNI + Processing Depth

  - by Alex Lu

  I am using Kinect with Simple OpenNI and Processing, and I was trying to use the Z position of a hand to emulate a button press. So far when I try it using one hand it works really well, however, when I try to get it to work with a second hand, only one of the hands work. (I know it can be more efficient by moving everything except the fill out of the if statements, but I kept those in there just in case I want to change the sizes or something.) irz and ilz are the initial Z positions of the hands when they are first recognized by onCreateHands and rz and lz are the current Z positions. As of now, the code works fine with one hand, but the other hand will either stay pressed or unpressed. If i comment one of the sections out, it works fine as well. if (rz - irz > 0) { pushStyle(); fill(60); ellipse(rx, ry, 10, 10); popStyle(); rpressed = true; } else { pushStyle(); noFill(); ellipse(rx, ry, 10, 10); popStyle(); rpressed = false; } if (lz - ilz > 0) { pushStyle(); fill(60); ellipse(lx, ly, 10, 10); popStyle(); lpressed = true; } else { pushStyle(); noFill(); ellipse(lx, ly, 10, 10); popStyle(); lpressed = false; } I tried outputting the values of rz - irz and lz - ilz and the numbers range from small negative values to small positive values (around -8 to 8) for lz - ilz. But rz - irz outputs numbers from around 8-30 depending on each time I run it and is never consistent. Also, when I comment out the code for the lz-ilz, the values for rz-irz look just fine and it operates as intended. Is there a reason tracking both Z positions throws off one hand? And is there a way to get it to work? Thanks!

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• asp.net mvc & jquery dialog: What approach do I take to add items to a dropdownlist/select list with

  - by Mark Redman

  Hi, I am new to MVC and have a grasp of the basic model, but still doing everything with postbacks etc. One aspect of the UI I want to build is to have a drop-down-list of items with a button to add an item to the database and refresh the list. Achieving this with WebForms was straight forward as everything was wrapped in UpdatePanels, but what is the best approach to achieve this using MVC? Part of the markup for the list and button look like this: <table> <tr> <td><%=Html.DropDownList("JobTitleSelectList", Model.JobTitleSelectList, "(select job title)", new { @class = "data-entry-field" })%></td> <td>&nbsp;</td> <td><a id="AddJobTitleDialogLink" href="javascript: addJobTitleDialog();" title="Add Job Title"><img id="AddJobTitleButtonImage" src="/Content/Images/Icons/16x16/PlusGrey.png" border="0" /></a></td> </tr> </table> The Dialog is a standard jquery Ui dialog, looks like this: <div id="SingleTextEntryDialog" style="display:none"> <table> <tr> <td>Name:</td> <td><input id="SingleTextEntryDialogText" type="text" size="25" /></td> </tr> </table> </div> I am guessing I need to put this into a UserControl / PartialView (are they the same thing?) Also with the strongly typed View how do I pass the Model or just the SelectList Property to the UserControl or is this not the case? Nor sure if there should be form in the dialog div? or how that is going to postback via ajax. Some examples show a lot of ajax code in the page something like: $.ajax({...}); I assume doing this using jquery is more code than asp.net webforms, but there is just more code to see doing a "View Source" on a page? Your comments appreciated.

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• log4bash: Cannot find a way to add MaxBackupIndex to this logger implementation

  - by Syffys

  I have been trying to modify this log4bash implementation but I cannot manage to make it work. Here's a sample: #!/bin/bash TRUE=1 FALSE=0 ############### Added for testing log4bash_LOG_ENABLED=$TRUE log4bash_rootLogger=$TRACE,f,s log4bash_appender_f=file log4bash_appender_f_dir=$(pwd) log4bash_appender_f_file=test.log log4bash_appender_f_roll_format=%Y%m log4bash_appender_f_roll=$TRUE log4bash_appender_f_maxBackupIndex=10 #################################### log4bash_abs(){ if [ "${1:0:1}" == "." ]; then builtin echo ${rootDir}/${1} else builtin echo ${1} fi } log4bash_check_app_dir(){ if [ "$log4bash_LOG_ENABLED" -eq $TRUE ]; then dir=$(log4bash_abs $1) if [ ! -d ${dir} ]; then #log a seperation line mkdir $dir fi fi } # Delete old log files # $1 Log directory # $2 Log filename # $3 Log filename suffix # $4 Max backup index log4bash_delete_old_files(){ ##### Added for testing builtin echo "Running log4bash_delete_old_files $@" &2 ##### if [ "$log4bash_LOG_ENABLED" -eq $TRUE ] && [ -n "$3" ] && [ "$4" -gt 0 ]; then local directory=$(log4bash_abs $1) local filename=$2 local maxBackupIndex=$4 local suffix=$(echo "${3}" | sed -re 's/[^.]/?/g') local logFileList=$(find "${directory}" -mindepth 1 -maxdepth 1 -name "${filename}${suffix}" -type f | xargs ls -1rt) local fileCnt=$(builtin echo -e "${logFileList}" | wc -l) local fileToDeleteCnt=$(($fileCnt-$maxBackupIndex)) local fileToDelete=($(builtin echo -e "${logFileList}" | head -n "${fileToDeleteCnt}" | sed ':a;N;$!ba;s/\n/ /g')) ##### Added for testing builtin echo "log4bash_delete_old_files About to start deletion ${fileToDelete[@]}" &2 ##### if [ ${fileToDeleteCnt} -gt 0 ]; then for f in "${fileToDelete[@]}"; do #### Added for testing builtin echo "Removing file ${f}" &2 #### builtin eval rm -f ${f} done fi fi } #Appender # $1 Log directory # $2 Log file # $3 Log file roll ? # $4 Appender Name log4bash_filename(){ builtin echo "Running log4bash_filename $@" &2 local format local filename log4bash_check_app_dir "${1}" if [ ${3} -eq 1 ];then local formatProp=${4}_roll_format format=${!formatProp} if [ -z ${format} ]; then format=$log4bash_appender_file_format fi local suffix=.`date "+${format}"` filename=${1}/${2}${suffix} # Old log files deletion local previousFilenameVar=int_${4}_file_previous local maxBackupIndexVar=${4}_maxBackupIndex if [ -n "${!maxBackupIndexVar}" ] && [ "${!previousFilenameVar}" != "${filename}" ]; then builtin eval export $previousFilenameVar=$filename log4bash_delete_old_files "${1}" "${2}" "${suffix}" "${!maxBackupIndexVar}" else builtin echo "log4bash_filename $previousFilenameVar = ${!previousFilenameVar}" fi else filename=${1}/${2} fi builtin echo $filename } ######################## Added for testing filename_caller(){ builtin echo "filename_caller Call $1" output=$(log4bash_abs $(log4bash_filename "${log4bash_appender_f_dir}" "${log4bash_appender_f_file}" "1" "log4bash_appender_f" )) builtin echo ${output} } #### Previous logs generation for i in {1101..1120}; do file="${log4bash_appender_f_file}.2012${i:2:3}" builtin echo "${file} $i" touch -m -t "2012${i}0000" ${log4bash_appender_f_dir}/$file done for i in {1..4}; do filename_caller $i done I expect log4bash_filename function to step into the following if only when the calculated log filename is different from the previous one: if [ -n "${!maxBackupIndexVar}" ] && [ "${!previousFilenameVar}" != "${filename}" ]; then For this scenario to apply, I'd need ${!previousFilenameVar} to be correctly set, but it's not the case, so log4bash_filename steps into this if all the time which is really not necessary... It looks like the issue is due to the following line not working properly: builtin eval export $previousFilenameVar=$filename I have a some theories to explain why: in the original code, functions are declared and exported as readonly which makes them unable to modify global variable. I removed readonly declarations in the above sample, but probleme persists. Function calls are performed in $() which should make them run into seperated shell instances so variable modified are not exported to the main shell But I cannot manage to find a workaround to this issue... Any help is appreciated, thanks in advance!

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• Using PHP session_id() to Make Sure iframe is Generated by Our Server Dynamically

  - by Michael Robinson

  We use iframes to show ads on our site. Iframes are used to allow us to keep the ad generation code and other site modules separate. As we track ad views on our site, and need to be able to keep an accurate count of which pagetype gets what views, I must ensure that users can't simply copy-paste the iframe in which the ad is loaded onto another site. This would cause ad count to become inflated for this page, and the count would not match the view count of the page the iframe "should" be displayed in. Before anyone says so: no I can't simply compare the page view count with the ad view count, or use the page view count * number of ads per page, as # of ads per page will not necessarily be static. I need to come up with a solution that will allow ads to be shown only for iframes that are generated dynamically and are shown on our pages. I am not familiar with PHP sessions, but from what little reading I have had time to do, the following seems to be to be an acceptable solution: Add "s = session_id()" to the src of the ad's iframe. In the code that receives and processes ad requests, only return (and count) and ad if s == session_id(). Please correct me if I'm wrong, but this would ensure: Ads would only be returned to iframes whose src was generated alongside the rest of the page's content, as is the case during normal use. We can return our logo to ad calls with an invalid session_id. So a simple example would be: One of our pages: <?php session_start(); ?> <div id="someElement"> <!-- EVERYONE LOVES ADS --> <iframe src="http//awesomesite.com/ad/can_has_ad.php?s=<?php echo session_id(); ?>></iframe> </div> ad/can_has_ad.php: <?php session_start(); ?> if($_GET['s'] == session_id()){ echo 'can has ad'; } else{ echo '<img src="http://awesomesite.com/images/canhaslogo.jpg"/>'; } And finally, copied code with static 's' parameter: <!-- HAHA LULZ I WILL SCREW WITH YOUR AD VIEW COUNTS LULZ HAHA --> <iframe src="http//awesomesite.com/ad/can_has_ad.php?s=77f2b5fcdab52f52607888746969b0ad></iframe> Which would give them an iframe showing our awesome site's logo, and not screw with our view counts. I made some basic test cases: two files, one that generates the iframe and echos it, and one that the iframe's src is pointed to, that checks the 's' parameter and shows an appropriate message depending on the result. I copied the iframe into a file and hosted it on a different server, and the correct message was displayed (cannot has ad). So, my question is: Would this work or am I being a PHP session noob, with the above test being a total fluke? Thanks for your time! Edit: I'm trying to solve this without touching the SQL server

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• Asp.net MVC jquery-ajax dont render html

  - by Troublesum

  Hi, Im trying to use jqeury ajax with MVC i can get it to post back to the action i want and it returns the ViewData objects with updated Data but never renders the HTML. I have i View which contains some MVC User Controls and i want them to update on a timer. Here is my View Markup <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/PageWithSummaryViewAndTabs.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="FullCaseTitle" ContentPlaceHolderID="TitleContent" runat="server"> </asp:Content> <asp:Content ID="FullCaseContent" ContentPlaceHolderID="MainContent" runat="server"> <script type="text/javascript"> window.setInterval(test, 5000); function test() { jQuery.get("/PatientCase/RefreshEPRF", function(response) { }); } </script> <div id="loadingDiv" style="display:none">Updating</div> <input id="refreshPatientCaseIndexButton" type="submit" visible="true" title="refresh" value="Refresh" /> <h2>Full Case</h2> <div id="EPRFContent"> <%Html.RenderPartial(@"~/Views/PatientCase/SectionEPRF.ascx"); %> <%Html.RenderPartial(@"~/Views/PatientCase/SectionDrugs.ascx"); %> </div> <div id="ImageContent"> <%Html.RenderPartial(@"~/Views/PatientCase/SectionImagery.ascx"); % On postback i call a Action Called RefreshEPRF which loads just the required user controls again <%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <%Html.RenderPartial(@"~/Views/PatientCase/SectionEPRF.ascx"); %> <%Html.RenderPartial(@"~/Views/PatientCase/SectionDrugs.ascx"); %> And finaly the marpup in the control <table id="detailstable"> <tr><td id="detailslablecolumn">Patient Name : </td><td> <% foreach (var item in (List<STS_Lite.Models.PatinetCase.EPRFItem>)ViewData["EPRF"]) { if (item.datumItemId == 46) { if (item.Stroke) { %> <img src="/PatientCaseIndex/InkImageData/GetInkImage/<%=ViewData["PatientCaseId"]%>/<%=ViewData["TemplateInstanceId"]%>/<%=item.TemplateItemId %>" /> <% } else {%> <%=item.Value.ToString()%> <%} break; } } %></td></tr><table> When i step through this code the ViewData in the user control has the new updated values but the page comes back with no new values. I have tried the jquery.get and ajax but with no luck. Any help would be great thanks

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• How to navigate to another html page?

  - by newbie

  In my application there's a usual login page sending username and password to the server script, where it needs to be authenticated, and in case of an authentic user, the server should redirect to a page student.html. This is my code var ports = 3000; var portt = 3001; var express = require('express'); var student = require('express')(); var teacher = require('express')(); var server_s = require('http').createServer(student); var server_t = require('http').createServer(teacher); var ios = require('socket.io').listen(server_s); var iot = require('socket.io').listen(server_t); var path = require('path'); server_s.listen(ports); server_t.listen(portt); student.use(express.static(path.join(__dirname, 'public'))); student.get('/', function(req,res){ res.sendfile(__dirname + '/login.html'); }); teacher.use(express.static(path.join(__dirname, 'public'))); teacher.get('/', function(req,res){ res.sendfile(__dirname + '/mytry.html'); }); ios.sockets.on('connection', function(socket){ var username, password; socket.on('check',function(data){ username = data[0]; password = data[1]; //************* Database connection and query ************* var mysql = require('mysql'); var connection = mysql.createConnection({ host : 'localhost', user : 'user', password: '*******', database: 'my_db' }); connection.connect(); var qstring = 'SELECT s_id FROM login_student WHERE username='+username+'AND password='+password; connection.query(qstring, function(err, rows, fields) { if (err) { console.log('ERROR: ' + err); socket.emit('login_failure','DB error'); return; } console.log('The solution is: ', rows[0].solution); if (rows>0) //***** Here i want redirection to another page ****** else socket.emit('login_failure','Invalid Username or password'); }); connection.end(); }); }); iot.sockets.on('connection', function(socket){ ; }); }); Can anyone suggest what should I do?

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• Normalizing Item Names & Synonyms

  - by RabidFire

  Consider an e-commerce application with multiple stores. Each store owner can edit the item catalog of his store. My current database schema is as follows: item_names: id | name | description | picture | common(BOOL) items: id | item_name_id | picture | price | description | picture item_synonyms: id | item_name_id | name | error(BOOL) Notes: error indicates a wrong spelling (eg. "Ericson"). description and picture of the item_names table are "globals" that can optionally be overridden by "local" description and picture fields of the items table (in case the store owner wants to supply a different picture for an item). common helps separate unique item names ("Jimmy Joe's Cheese Pizza" from "Cheese Pizza") I think the bright side of this schema is: Optimized searching & Handling Synonyms: I can query the item_names & item_synonyms tables using name LIKE %QUERY% and obtain the list of item_name_ids that need to be joined with the items table. (Examples of synonyms: "Sony Ericsson", "Sony Ericson", "X10", "X 10") Autocompletion: Again, a simple query to the item_names table. I can avoid the usage of DISTINCT and it minimizes number of variations ("Sony Ericsson Xperia™ X10", "Sony Ericsson - Xperia X10", "Xperia X10, Sony Ericsson") The down side would be: Overhead: When inserting an item, I query item_names to see if this name already exists. If not, I create a new entry. When deleting an item, I count the number of entries with the same name. If this is the only item with that name, I delete the entry from the item_names table (just to keep things clean; accounts for possible erroneous submissions). And updating is the combination of both. Weird Item Names: Store owners sometimes use sentences like "Harry Potter 1, 2 Books + CDs + Magic Hat". There's something off about having so much overhead to accommodate cases like this. This would perhaps be the prime reason I'm tempted to go for a schema like this: items: id | name | picture | price | description | picture (... with item_names and item_synonyms as utility tables that I could query) Is there a better schema you would suggested? Should item names be normalized for autocomplete? Is this probably what Facebook does for "School", "City" entries? Is the first schema or the second better/optimal for search? Thanks in advance! References: (1) Is normalizing a person's name going too far?, (2) Avoiding DISTINCT

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• XY-Scatter Chart In SSRS Won't Display Points

  - by Dalin Seivewright

  I'm a bit confused with this one. I have a Dataset with a BackupDate and a BackupTime as well as a BackupType. The BackupDate is comprised of 12 characters from the left of a datetime string within a table. The BackupTime is comprised of 8 characters from the right of that same datetime string. So for example: BackupDate would be 'December 12 2008' and the BackupTime would be '12:53PM.' I have added an XY-scatter chart to the report. I've added a 'series' value for the BackupType (so one can distinguish between a Full/Incr/Log backup). I've added a category value of BackupDate and set the Scale for the X-axis from the Min of BackupDate to the Max of BackupDate. I've then added an item to the Values with the Y variable set to BackupTime and the X variable set to BackupDate. The interval for the Y-axis is 12:00AM to 11:59PM and the formatting for the labels is 'hh:mmtt'. The BackupTime matches the format of the Y-axis. The BackupDate matches the format of the X-axis. 10 entries are retrieved by my Dataset and the Legend is properly populated by the BackupType field. No points are being plotted on the graph and no markers/pointers are shown if they are enabled. There should be a point on the graph for every point in time of each day there is a backup of a specific type. Am I missing something? Does anyone know of a good tutorial dealing specifically with XY-scatter graphs and using them in a way I intend? I am using the 2005 version of SSRS rather than the 2008 version. Screenshot of what my chart currently looks like: In case it could be dataset related: SELECT TOP (10) backup_type, LTRIM(RTRIM(LEFT(backup_finish_date, 12))) AS BackupDate, LTRIM(RTRIM(RIGHT(backup_finish_date, 8))) AS BackupTime FROM DBARepository.Backup_History As requested, here are the results of this query. There is a Where clause to constrain the results to a specific database of a specific server that was not included in the above SQL Query. Log Dec 26 2008 12:00PM Log Dec 27 2008 4:00AM Log Dec 27 2008 8:00AM Log Dec 27 2008 12:00PM Log Dec 27 2008 4:00PM Log Dec 27 2008 8:00PM Database Dec 27 2008 10:01PM Log Dec 28 2008 12:00AM Log Dec 28 2008 4:00AM Log Dec 28 2008 8:00AM

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• Smoke testing a .NET web application

  - by pdr

  I cannot believe I'm the first person to go through this thought process, so I'm wondering if anyone can help me out with it. Current situation: developers write a web site, operations deploy it. Once deployed, a developer Smoke Tests it, to make sure the deployment went smoothly. To me this feels wrong, it essentially means it takes two people to deploy an application; in our case those two people are on opposite sides of the planet and timezones come into play, causing havoc. But the fact remains that developers know what the minimum set of tests is and that may change over time (particularly for the web service portion of our app). Operations, with all due respect to them (and they would say this themselves), are button-pushers who need a set of instructions to follow. The manual solution is that we document the test cases and operations follow that document each time they deploy. That sounds painful, plus they may be deploying different versions to different environments (specifically UAT and Production) and may need a different set of instructions for each. On top of this, one of our near-future plans is to have an automated daily deploy environment, so then we'll have to instruct a computer as to how to deploy a given version of our app. I would dearly like to add to that instructions for how to smoke test the app. Now developers are better at documenting instructions for computers than they are for people, so the obvious solution seems to be to use a combination of nUnit (I know these aren't unit tests per se, but it is a built-for-purpose test runner) and either the Watin or Selenium APIs to run through the obvious browser steps and call to the web service and explain to the Operations guys how to run those unit tests. I can do that; I have mostly done it already. But wouldn't it be nice if I could make that process simpler still? At this point, the Operations guys and the computer are going to have to know which set of tests relate to which version of the app and tell the nUnit runner which base URL it should point to (say, www.example.com = v3.2 or test.example.com = v3.3). Wouldn't it be nicer if the test runner itself had a way of giving it a base URL and letting it download say a zip file, unpack it and edit a configuration file automatically before running any test fixtures it found in there? Is there an open source app that would do that? Is there a need for one? Is there a solution using something other than nUnit, maybe Fitnesse? For the record, I'm looking at .NET-based tools first because most of the developers are primarily .NET developers, but we're not married to it. If such a tool exists using other languages to write the tests, we'll happily adapt, as long as there is a test runner that works on Windows.

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• UIButtons creating a native-like keyboard behavior.

  - by camilo

  Greets. A somehow detailed explanation on my problem, and what I have already done, and what I cannot do. I want to create a behavior resembling the one in the iPhone's keyboard. Basically, I want a view to appear when the user taps a button and WHILE the user taps that button. This, I accomplished. When the user lets go of the button WHILE his finger is on that button's area, I want to trigger an action "doing stuff". This, I was also able to do. Since all the buttons are near (like in the keyboard) and I don't want the user to select other button than the one he pressed, I reduced the hit area for the button using the -(BOOL)pointInside:(CGPoint)point withEvent:(UIEvent )event function. When the user presses the button, not lifting its finger, and dragging outside the button area, I want another action to trigger. This is the first problem... This function only triggers when the user's finger is far from the buttons' area, and this time the pointInside function is not being my friend. How can I detect the user finger "left" the button area the moment it exits its bounds? This, in case you didn't realize... was problem 1. The second problem is related with the drag enter. Again, I need to limit the area like in the drag exit. But I suppose that when I solve one of these, the other is the same. The problem is that in order to have a behavior like in the keyboard, I may need to detect the user started the touch in another button, never lifted his finger, and changed to another button. I can detect drag enter and drag exit IN THIS ORDER while on the same button. I cannot detect drag enter when the user first touched anywhere else other than the button where I want to detect the drag enter event. Basically what I need is to detect touch on any button (and not anywhere else in the view), and while the user is changing buttons without lifting the finger, I want to detect the new button being touched. This gigantic paragraph was problem #2. Any help, as you might guess, is highly appreciated. Best Regards. Thanks a lot!

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• itertools.product eliminating repeated reversed tuples

  - by genclik27

  I asked a question yesterday and thanks to Tim Peters, it is solved. The question is here; itertools.product eliminating repeated elements The new question is further version of this. This time I will generate tuples inside of tuples. Here is an example; lis = [[(1,2), (3,4)], [(5,2), (1,2)], [(2,1), (1,2)]] When I use it in itertools.product function this is what I get, ((1, 2), (5, 2), (2, 1)) ((1, 2), (5, 2), (1, 2)) ((1, 2), (1, 2), (2, 1)) ((1, 2), (1, 2), (1, 2)) ((3, 4), (5, 2), (2, 1)) ((3, 4), (5, 2), (1, 2)) ((3, 4), (1, 2), (2, 1)) ((3, 4), (1, 2), (1, 2)) I want to change it in a way that if a sequence has (a,b) inside of it, then it can not have (b,a). In this example if you look at this sequence ((3, 4), (1, 2), (2, 1)) it has (1,2) and (2,1) inside of it. So, this sequence ((3, 4), (1, 2), (2, 1)) should not be considered in the results. As I said, I asked similar question before, in that case it was not considering duplicate elements. I try to adapt it to my problem. Here is modified code. Changed parts in old version are taken in comments. def reverse_seq(seq): s = [] for i in range(len(seq)): s.append(seq[-i-1]) return tuple(s) def uprod(*seqs): def inner(i): if i == n: yield tuple(result) return for elt in sets[i] - reverse: #seen.add(elt) rvrs = reverse_seq(elt) reverse.add(rvrs) result[i] = elt for t in inner(i+1): yield t #seen.remove(elt) reverse.remove(rvrs) sets = [set(seq) for seq in seqs] n = len(sets) #seen = set() reverse = set() result = [None] * n for t in inner(0): yield t In my opinion this code should work but I am getting error for the input lis = [[(1,2), (3,4)], [(5,2), (1,2)], [(2,1), (1,2)]]. I could not understand where I am wrong. for i in uprod(*lis): print i Output is, ((1, 2), (1, 2), (1, 2)) Traceback (most recent call last): File "D:\Users\SUUSER\workspace tree\sequence_covering _array\denemeler_buraya.py", line 39, in <module> for i in uprod(*lis): File "D:\Users\SUUSER\workspace tree\sequence_covering _array\denemeler_buraya.py", line 32, in uprod for t in inner(0): File "D:\Users\SUUSER\workspace tree\sequence_covering _array\denemeler_buraya.py", line 22, in inner for t in inner(i+1): File "D:\Users\SUUSER\workspace tree\sequence_covering _array\denemeler_buraya.py", line 25, in inner reverse.remove(rvrs) KeyError: (2, 1) Thanks,

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• log4net initialisation

  - by Ruben Bartelink

  I've looked hard for duplicates but have to ask the following, no matter how basic it may seem, to get it clear once and for all! In a fresh Console app using log4net version 1.2.10.0 on VS28KSP1 on 64 bit W7, I have the following code:- using log4net; using log4net.Config; namespace ConsoleApplication1 { class Program { static readonly ILog _log = LogManager.GetLogger(typeof(Program)); static void Main(string[] args) { _log.Info("Ran"); } } } In my app.config, I have: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" /> </configSections> <log4net> <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender"> <file value="Program.log" /> <lockingModel type="log4net.Appender.FileAppender+MinimalLock" /> <appendToFile value="true" /> <rollingStyle value="Size" /> <maxSizeRollBackups value="10" /> <maximumFileSize value="1MB" /> <staticLogFileName value="true" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="[%username] %date [%thread] %-5level %logger [%property{NDC}] - %message%newline" /> </layout> </appender> <root> <level value="DEBUG" /> <appender-ref ref="RollingFileAppender" /> </root> </log4net> </configuration> This doesnt write anything, unless I either add an attribute: [ assembly:XmlConfigurator ] Or explicitly initialise it in Main(): _log.Info("This will not go to the log"); XmlConfigurator.Configure(); _log.Info("Ran"); This raises the following questions: I'm almost certain I've seen it working somewhere on some version of log4net without the addition of the assembly attribute or call in Main. Can someone assure me I'm not imagining that? Can someone please point me to where in the doc it explicitly states that both the config section and the initialisation hook are required - hopefully with an explanation of when this changed, if it did? I can easily imagine why this might be the policy -- having the initialisation step explicit to avoid surprises etc., it's just that I seem to recall this not always being the case... (And normally I have the config in a separate file, which generally takes configsections out of the picture)

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• .NET: Is there a way to finagle a default namespace in an XPath 1.0 query?

  - by Cheeso

  I'm building a tool that performs xpath 1.0 queries on XHTML documents. The requirement to use a namespace prefix in the query is killing me. The query looks like this: html/body/div[@class='contents']/div[@class='body']/ div[@class='pgdbbyauthor']/h2[a[@name][starts-with(.,'Quick')]]/ following-sibling::ul[1]/li/a (all on one line) ...which is bad enough, except because it's xpath 1.0, I need to use an explicit namespace prefix on each QName, so it looks like this: ns1:html/ns1:body/ns1:div[@class='contents']/ns1:div[@class='body']/ ns1:div[@class='pgdbbyauthor']/ns1:h2[ns1:a[@name][starts-with(.,'Quick')]]/ following-sibling::ns1:ul[1]/ns1:li/ns1:a To set up the query, I do something like this: var xpathDoc = new XPathDocument(new StringReader(theText)); var nav = xpathDoc.CreateNavigator(); var xmlns = new XmlNamespaceManager(nav.NameTable); foreach (string prefix in xmlNamespaces.Keys) xmlns.AddNamespace(prefix, xmlNamespaces[prefix]); XPathNodeIterator selection = nav.Select(xpathExpression, xmlns); But what I want is for the xpathExpression to use the implicit default namespace. Is there a way for me to transform the unadorned xpath expression, after it's been written, to inject a namespace prefix for each element name in the query? I'm thinking, anything between two slashes, I could inject a prefix there. Excepting of course axis names like "parent::" and "preceding-sibling::" . And wildcards. That's what I mean by "finagle a default namespace". Is this hack gonna work? Addendum Here's what I mean. suppose I have an xpath expression, and before passing it to nav.Select(), I transform it. Something like this: string FixupWithDefaultNamespace(string expr) { string s = expr; s = Regex.Replace(s, "^(?!::)([^/:]+)(?=/)", "ns1:$1"); // beginning s = Regex.Replace(s, "/([^/:]+)(?=/)", "/ns1:$1"); // stanza s = Regex.Replace(s, "::([A-Za-z][^/:*]*)(?=/)", "::ns1:$1"); // axis specifier s = Regex.Replace(s, "\\[([A-Za-z][^/:*\\(]*)(?=[\\[\\]])", "[ns1:$1"); // predicate s = Regex.Replace(s, "/([A-Za-z][^/:]*)(?!<::)$", "/ns1:$1"); // end s = Regex.Replace(s, "^([A-Za-z][^/:]*)$", "ns1:$1"); // edge case s = Regex.Replace(s, "([-A-Za-z]+)\\(([^/:\\.,\\)]+)(?=[,\\)])", "$1(ns1:$2"); // xpath functions return s; } This actually works for simple cases I tried. To use the example from above - if the input is the first xpath expression, the output I get is the 2nd one, with all the ns1 prefixes. The real question is, is it hopeless to expect this Regex.Replace approach to work, as the xpath expressions get more complicated?

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• How to update NSMutableDictionary. My code doesn't work.

  - by dawatson833

  I've populated an array using. arrSettings = [[NSMutableArray alloc] initWithContentsOfFile:[self settingsPath]]; The file is a plist with the root as an array and then a dictionary with three three keys defined as number. I've also tried setting the keys to string. I display the values in the plist file on a view using. diaper = [[arrSettings objectAtIndex:0] objectForKey:@"Diaper Expenses"]; oil = [[arrSettings objectAtIndex:0] objectForKey:@"Oil Used"]; tree = [[arrSettings objectAtIndex:0] objectForKey:@"Wood Used"]; This code works fine, the values in the dictionary are assigned to the variables and they are displayed. The user can make changes and then press a save button. I use this code to extract the dictionary part of the array so I can update it. The assignment to editDictionary works. I've double checked the key names including case and that is correct. editDictionary = [[NSMutableDictionary alloc] init]; editDictionary = [arrSettings objectAtIndex:0]; NSNumber *myNumber = [NSNumber numberWithFloat:diaperAmount]; [editDictionary setValue:myNumber forKey:@"Diaper Expenses"]; myNumber = [NSNumber numberWithFloat:oilAmount]; [editDictionary setValue:myNumber forKey:@"Oil Used"]; myNumber = [NSNumber numberWithFloat:treeAmount]; [editDictionary setValue:myNumber forKey:@"Wood Used"]; In this example I've used a nsnumber. But I've also tried the xxxAmount field as part of SetValue instead of creating a NSNumber. Neither implementation works. Several strange things happen. Sometimes the first two setvalue statements work, but the last setvalue fails with a EXC_BAD_ACCESS failure. Other times the first setValue fails with the same error. I have no idea why the first two sometimes work. I'm at a loss of what to do next. I've tried several implentations and none of them work. Also, in the debugger how can I display the editDictionary elements. I can see editDictionary, but I don't know how to display the individual elements.

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• Problem to focus JTextField

  - by Tom Brito

  I have used the approach of the ComponentListener to call focus in JTextField within a dialog, but for this case is just not working, I don't know why. It shows the focus in the text field and fast change to the button. Run and see: import java.awt.Component; import java.awt.GridLayout; import java.awt.event.ComponentEvent; import java.awt.event.ComponentListener; import javax.swing.JDialog; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; import javax.swing.JPasswordField; import javax.swing.JTextField; public class User { private String username = ""; private String password = ""; public User() { // default constructor } public User(String username, String password) { this.username = username; this.password = password; } /** Create a panel containing the componet and tha label. */ public JPanel createLabeledComponent(JLabel label, Component comp) { GridLayout layout = new GridLayout(2, 1); JPanel panel = new JPanel(layout); panel.add(label); panel.add(comp); label.setLabelFor(comp); return panel; } public void showEditDialog() { JLabel usernameLbl = new JLabel(username); final JTextField usernameField = new JTextField(); usernameField.setText(username); JPanel usernamePnl = createLabeledComponent(usernameLbl, usernameField); JLabel passwordLbl = new JLabel(password); JPasswordField passwordField = new JPasswordField(password); JPanel passwordPnl = createLabeledComponent(passwordLbl, passwordField); Object[] fields = { "User:", usernamePnl, "Password:", passwordPnl }; JOptionPane optionPane = new JOptionPane(fields, JOptionPane.PLAIN_MESSAGE, JOptionPane.OK_CANCEL_OPTION, null, null); JDialog dialog = optionPane.createDialog("User Data"); dialog.addComponentListener(new ComponentListener() { public void componentShown(ComponentEvent e) { usernameField.requestFocusInWindow(); } public void componentResized(ComponentEvent e) {} public void componentMoved(ComponentEvent e) {} public void componentHidden(ComponentEvent e) {} }); dialog.setVisible(true); } public static void main(String[] args) { new User().showEditDialog(); } } Any idea how to solve this?

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• Memory corruption in System.Move due to changed 8087CW mode (png + stretchblt)

  - by André Mussche

  I have strange a memory corruption problem. After many hours debugging and trying I think I found something. For example: I do a simple string assignment: sTest := 'SET LOCK_TIMEOUT '; However, the result sometimes becomes: sTest = 'SET LOCK'#0'TIMEOUT ' So, the _ gets replaced by an 0 byte. I have seen this happening once (reproducing is tricky, dependent on timing) in the System.Move function, when it uses the FPU stack (fild, fistp) for fast memory copy (in case of 9 till 32 bytes to move): ... @@SmallMove: {9..32 Byte Move} fild qword ptr [eax+ecx] {Load Last 8} fild qword ptr [eax] {Load First 8} cmp ecx, 8 jle @@Small16 fild qword ptr [eax+8] {Load Second 8} cmp ecx, 16 jle @@Small24 fild qword ptr [eax+16] {Load Third 8} fistp qword ptr [edx+16] {Save Third 8} ... Using the FPU view and 2 memory debug views (Delphi - View - Debug - CPU - Memory) I saw it going wrong... once... could not reproduce however... This morning I read something about the 8087CW mode, and yes, if this is changed into $27F I get memory corruption! Normally it is $133F: The difference between $133F and $027F is that $027F sets up the FPU for doing less precise calculations (limiting to Double in stead of Extended) and different infiniti handling (which was used for older FPU’s, but is not used any more). Okay, now I found why but not when! I changed the working of my AsmProfiler with a simple check (so all functions are checked at enter and leave): if Get8087CW = $27F then //normally $1372? if MainThreadID = GetCurrentThreadId then //only check mainthread DebugBreak; I "profiled" some units and dll's and bingo (see stack): Windows.StretchBlt(3372289943,0,0,514,345,4211154027,0,0,514,345,13369376) pngimage.TPNGObject.DrawPartialTrans(4211154027,(0, 0, 514, 345, (0, 0), (514, 345))) pngimage.TPNGObject.Draw($7FF62450,(0, 0, 514, 345, (0, 0), (514, 345))) Graphics.TCanvas.StretchDraw((0, 0, 514, 345, (0, 0), (514, 345)),$7FECF3D0) ExtCtrls.TImage.Paint Controls.TGraphicControl.WMPaint((15, 4211154027, 0, 0)) So it is happening in StretchBlt... What to do now? Is it a fault of Windows, or a bug in PNG (included in D2007)? Or is the System.Move function not failsafe?

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• How do we simplify this kind of code in Java? Something like macros in C?

  - by Terry Li

  public static boolean diagonals(char[][] b, int row, int col, int l) { int counter = 1; // because we start from the current position char charAtPosition = b[row][col]; int numRows = b.length; int numCols = b[0].length; int topleft = 0; int topright = 0; int bottomleft = 0; int bottomright = 0; for (int i=row-1,j=col-1;i>=0 && j>=0;i--,j--) { if (b[i][j]==charAtPosition) { topleft++; } else { break; } } for (int i=row-1,j=col+1;i>=0 && j<=numCols;i--,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } for (int i=row+1,j=col-1;i<=numRows && j>=0;i++,j--) { if (b[i][j]==charAtPosition) { bottomleft++; } else { break; } } for (int i=row+1,j=col+1;i<=numRows && j<=numCols;i++,j++) { if (b[i][j]==charAtPosition) { bottomright++; } else { break; } } return topleft + bottomright + 1 >= l || topright + bottomleft + 1 >= l; //in this case l is 5 } After I was done posting the code above here, I couldn't help but wanted to simplify the code by merging the four pretty much the same loops into one method. Here's the kind of method I want to have: public int countSteps(char horizontal, char vertical) { } Two parameters horizontal and vertical can be either + or - to indicate the four directions to walk in. What I want to see if possible at all is i++; is generalized to i horizontal horizontal; when horizontal taking the value of +. What I don't want to see is if or switch statements, for example: public int countSteps(char horizontal, char vertical) { if (horizontal == '+' && vertical == '-') { for (int i=row-1,j=col+1;i>=0 && j<=numCols;i--,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } } else if (horizontal == '+' && vertical == '+') { for (int i=row+1,j=col+1;i>=0 && j<=numCols;i++,j++) { if (b[i][j]==charAtPosition) { topright++; } else { break; } } } else if () { } else { } } Since it is as tedious as the original one. Note also that the comparing signs for the loop condition i>=0 && j<=numCols; for example, >= && <= have correspondence with the value combination of horizontal and vertical. Sorry for my bad wording, please let me know if anything is not clear.

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• Backtracking infinite loop

  - by Greenhorn

  This is Exercise 28.1.2 from HtDP. I've successfully implemented the neighbors function and all test cases pass. (define Graph (list (list 'A (list 'B 'E)) (list 'B (list 'E 'F)) (list 'C (list 'D)) (list 'D empty) (list 'E (list 'C 'F)) (list 'F (list 'D 'G)) (list 'G empty))) (define (first-line n alist) (cond [(symbol=? (first alist) n) alist] [else empty])) ;; returns empty if node is not in graph (define (neighbors n g) (cond [(empty? g) empty] [(cons? (first g)) (cond [(symbol=? (first (first g)) n) (first-line n (first g))] [else (neighbors n (rest g))])])) ; test cases (equal? (neighbors 'A Graph) (list 'A (list 'B 'E))) (equal? (neighbors 'B Graph) (list 'B (list 'E 'F))) (equal? (neighbors 'C Graph) (list 'C (list 'D))) (equal? (neighbors 'D Graph) (list 'D empty)) (equal? (neighbors 'E Graph) (list 'E (list 'C 'F))) (equal? (neighbors 'F Graph) (list 'F (list 'D 'G))) (equal? (neighbors 'G Graph) (list 'G empty)) (equal? (neighbors 'H Graph) empty) The problem comes when I copy-paste the code from Figure 77 of the text. It is supposed to determine whether a destination node is reachable from an origin node. However it appears that the code goes into an infinite loop except for the most trivial case where the origin and destination nodes are the same. ;; find-route : node node graph -> (listof node) or false ;; to create a path from origination to destination in G ;; if there is no path, the function produces false (define (find-route origination destination G) (cond [(symbol=? origination destination) (list destination)] [else (local ((define possible-route (find-route/list (neighbors origination G) destination G))) (cond [(boolean? possible-route) false] [else (cons origination possible-route)]))])) ;; find-route/list : (listof node) node graph -> (listof node) or false ;; to create a path from some node on lo-Os to D ;; if there is no path, the function produces false (define (find-route/list lo-Os D G) (cond [(empty? lo-Os) false] [else (local ((define possible-route (find-route (first lo-Os) D G))) (cond [(boolean? possible-route) (find-route/list (rest lo-Os) D G)] [else possible-route]))])) Does the problem lie in my code? Thank you.

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• Monitoring UDP socket in glib(mm) eats up CPU time

  - by Gyorgy Szekely

  Hi, I have a GTKmm Windows application (built with MinGW) that receives UDP packets (no sending). The socket is native winsock and I use glibmm IOChannel to connect it to the application main loop. The socket is read with recvfrom. My problem is: this setup eats 25% percent CPU time on a 3GHz workstation. Can somebody tell me why? The application is idle in this case, and if I remove the UDP code, CPU usage drops down to almost zero. As the application has to perform some CPU intensive tasks, I could image better ways to spend that 25% Here are some code excerpts: (sorry for the printf's ;) ) /* bind */ void UDPInterface::bindToPort(unsigned short port) { struct sockaddr_in target; WSADATA wsaData; target.sin_family = AF_INET; target.sin_port = htons(port); target.sin_addr.s_addr = 0; if ( WSAStartup ( 0x0202, &wsaData ) ) { printf("WSAStartup failed!\n"); exit(0); // :) WSACleanup(); } sock = socket( AF_INET, SOCK_DGRAM, 0 ); if (sock == INVALID_SOCKET) { printf("invalid socket!\n"); exit(0); } if (bind(sock,(struct sockaddr*) &target, sizeof(struct sockaddr_in) ) == SOCKET_ERROR) { printf("failed to bind to port!\n"); exit(0); } printf("[UDPInterface::bindToPort] listening on port %i\n", port); } /* read */ bool UDPInterface::UDPEvent(Glib::IOCondition io_condition) { recvfrom(sock, (char*)buf, BUF_SIZE*4, 0, NULL, NULL); /* process packet... */ } /* glibmm connect */ Glib::RefPtr channel = Glib::IOChannel::create_from_win32_socket(udp.sock); Glib::signal_io().connect( sigc::mem_fun(udp, &UDPInterface::UDPEvent), channel, Glib::IO_IN ); I've read here in some other question, and also in glib docs (g_io_channel_win32_new_socket()) that the socket is put into nonblocking mode, and it's "a side-effect of the implementation and unavoidable". Does this explain the CPU effect, it's not clear to me? Whether or not I use glib to access the socket or call recvfrom() directly doesn't seem to make much difference, since CPU is used up before any packet arrives and the read handler gets invoked. Also glibmm docs state that it's ok to call recvfrom() even if the socket is polled (Glib::IOChannel::create_from_win32_socket()) I've tried compiling the program with -pg and created a per function cpu usage report with gprof. This wasn't usefull because the time is not spent in my program, but in some external glib/glibmm dll.

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• Nested Transaction issues within custom Windows Service

  - by pdwetz

  I have a custom Windows Service I recently upgraded to use TransactionScope for nested transactions. It worked fine locally on my old dev machine (XP sp3) and on a test server (Server 2003). However, it fails on my new Windows 7 machine as well as on 2008 Server. It was targeting 2.0 framework; I tried targeting 3.5 instead, but it still fails. The strange part is really in how it fails; no exception is thrown. The service itself merely times out. I added tracing code, and it fails when opening the connection for Database lookup #2 below. I also enabled tracing for System.Transactions; it literally cuts out partway while writing the block for the failed connection. We ran a SQL trace, but only the first lookup shows up. I put in code traces, and it gets to the trace the line before the second lookup, but nothing after. I've had the same experience hitting two different SQL servers (both are SQL 2005 running on Server 2003). The connection string is utilizing a SQL account (not Windows integration). All connections are against the same database in this case, but given the nature of the code it is being escalated to MSDTC. Here's the basic code structure: TransactionOptions options = new TransactionOptions(); options.IsolationLevel = System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.RequiresNew, options)) { // Database lookup #1 TransactionOptions options = new TransactionOptions(); options.IsolationLevel = Transaction.Current != null ? Transaction.Current.IsolationLevel : System.Transactions.IsolationLevel.ReadCommitted; using (TransactionScope scope = new TransactionScope(TransactionScopeOption.Required, options)) { // Database lookup #2; fails on connection.Open() // Database save (never reached) scope.Complete();<br/> } scope.Complete();<br/> } My local firewall is disabled. The service normally runs using Network Service, but I also tried my user account (same results). The short of it is that I use the same general technique widely in my web applications and haven't had any issues. I pulled out the code and ran it fine within a local Windows Form application. If anyone has any additional debugging ideas (or, even better, solutions) I'd love to hear them.

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• Android Bluetooth Fails to Pair

  - by CaseyB

  I am having a problem getting my devices to pair in Android. If I go into the settings and pair them manually I can get them to connect using the following code: Server // Make sure the device it discoverable mServerSocket = mAdapter.listenUsingRfcommWithServiceRecord("Moo Productions Bluetooth Server", mUUID); mState = State.ACCEPTING; BluetoothSocket socket = mServerSocket.accept(); mServerSocket.close(); connected(socket); Client Set<BluetoothDevice> pairedDevices = mAdapter.getBondedDevices(); BluetoothSocket socket = null; // Search the list of paired devices for the right one for(BluetoothDevice device : pairedDevices) { try { mState = State.SEARCHING; socket = device.createRfcommSocketToServiceRecord(mUUID); mState = State.CONNECTING; socket.connect(); connected(socket); break; } catch (IOException e) { socket = null; continue; } } But if the devices hadn't already been paired it gets out of the foreach without connecting to a valid socket. In that case I start discovering. // If that didn't work, discover if(socket == null) { mState = State.SEARCHING; mReceiver = new SocketReceiver(); mContext.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND)); mAdapter.startDiscovery(); } // ... Later ... private class SocketReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent intent) { if(BluetoothDevice.ACTION_FOUND.equals(intent.getAction())) { try { // Get the device and try to open a socket BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); BluetoothSocket socket = device.createRfcommSocketToServiceRecord(mUUID); mState = State.CONNECTING; socket.connect(); // This is our boy, so stop looking mAdapter.cancelDiscovery(); mContext.unregisterReceiver(mReceiver); connected(socket); } catch (IOException ioe) { ioe.printStackTrace(); } } } } But it will never find the other device. I never get a pairing dialog and when I step through I see that it discovers the correct device, but it fails to connect with this exception java.io.IOException: Service discovery failed. Any ideas as to what I'm missing?

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