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  • Pagination links broken - php/jquery

    - by ClarkSKent
    Hey, I'm still trying to get my pagination links to load properly dynamically. But I can't seem to find a solution to this one problem. vote down star Hi everyone, I am still trying to figure out how to fix my pagination script to work properly. the problem I am having is when I click any of the pagination number links to go the next page, the new content does not load. literally nothing happens and when looking at the console in Firebug, nothing is sent or loaded. I have on the main page 3 links to filter the content and display it. When any of these links are clicked the results are loaded and displayed along with the associated pagination numbers for that specific content. I believe the problem is coming from the sql query in generate_pagination.php (seen below). When I hard code the sql category part it works, but is not dynamic at all. This is why I'm calling $ids=$_GET['ids']; and trying to put that into the category section but then the numbers don't display at all. If I echo out the $ids variable and click on a filter it does display the correct name/id, so I don't know why this doesn't work Here is the main page so you can see how I am including and starting the function(I'm new to php): <?php include_once('generate_pagination.php'); ?> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.1/jquery.min.js"></script> <script type="text/javascript" src="jquery_pagination.js"></script> <div id="loading" ></div> <div id="content" data-page="1"></div> <ul id="pagination"> <?php //Pagination Numbers for($i=1; $i<=$pages; $i++) { echo '<li class="page_numbers" id="page'.$i.'">'.$i.'</li>'; } ?> </ul> <br /> <br /> <a href="#" class="category" id="marketing">Marketing</a> <a href="#" class="category" id="automotive">Automotive</a> <a href="#" class="category" id="sports">Sports</a> Here is the generate pagination where the problem seems to occur: <?php $ids=$_GET['ids']; include_once('config.php'); $per_page = 3; //Calculating no of pages $sql = "SELECT COUNT(*) FROM explore WHERE category='$ids'"; $result = mysql_query($sql); $count = mysql_fetch_row($result); $pages = ceil($count[0]/$per_page); ?> I thought I might as well post the jquery script if someone wants to see: $(document).ready(function(){ //Display Loading Image function Display_Load() { $("#loading").fadeIn(900,0); $("#loading").html("<img src='bigLoader.gif' />"); } //Hide Loading Image function Hide_Load() { $("#loading").fadeOut('slow'); }; //Default Starting Page Results $("#pagination li:first").css({'color' : '#FF0084'}).css({'border' : 'none'}); Display_Load(); $("#content").load("pagination_data.php?page=1", Hide_Load()); // Editing below. // Sort content Marketing $("a.category").click(function() { Display_Load(); var this_id = $(this).attr('id'); $.get("pagination.php", { category: this.id }, function(data){ //Load your results into the page var pageNum = $('#content').attr('data-page'); $("#pagination").load('generate_pagination.php?category=' + pageNum +'&ids='+ this_id ); $("#content").load("filter_marketing.php?page=" + pageNum +'&id='+ this_id, Hide_Load()); }); }); //Pagination Click $("#pagination li").click(function(){ Display_Load(); //CSS Styles $("#pagination li") .css({'border' : 'solid #dddddd 1px'}) .css({'color' : '#0063DC'}); $(this) .css({'color' : '#FF0084'}) .css({'border' : 'none'}); //Loading Data var pageNum = $(this).attr("id").replace("page",""); $("#content").load("pagination_data.php?page=" + pageNum, function(){ $(this).attr('data-page', pageNum); Hide_Load(); }); }); }); If any could assist me on solving this problem that would be great, thanks.

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  • Authlogic Facebook Connect and cucumber

    - by jspooner
    I added the authlogic_facebook_connect plugin to my project and I'm now having problem running my cucumber test because of a NoMethodError. undefined method `set_facebook_session' for nil:NilClass (NoMethodError) In authlogic_facebook_connect/Session.rb the method "authenticating_with_facebook_connect?" is called as some sort of callback and the controller is defined but is missing the 'set_facebook_session' method. def authenticating_with_facebook_connect? controller.set_facebook_session attempted_record.nil? && errors.empty? && controller.facebook_session end I don't understand why the cucumber test is not loading the controller with this method. I also test the app in development and cucumber environments and everything works perfect. Here is the full cucumber output. Feature: Authentication In order to keep security a user should only be able to edit their own profile Background: # features/authorization.feature:4 Given a valid user record for joe_runner # features/step_definitions/user_steps.rb:4 undefined method `set_facebook_session' for nil:NilClass (NoMethodError) ./vendor/plugins/authlogic/lib/authlogic/controller_adapters/abstract_adapter.rb:63:in `send' ./vendor/plugins/authlogic/lib/authlogic/controller_adapters/abstract_adapter.rb:63:in `method_missing' ./vendor/plugins/authlogic_facebook_connect/lib/authlogic_facebook_connect/session.rb:132:in `authenticating_with_facebook_connect?' ./vendor/plugins/authlogic/lib/authlogic/session/callbacks.rb:83:in `validate' ./vendor/plugins/authlogic/lib/authlogic/session/validation.rb:64:in `valid?' ./vendor/plugins/authlogic/lib/authlogic/session/existence.rb:65:in `save' ./vendor/plugins/authlogic/lib/authlogic/session/existence.rb:30:in `create' ./vendor/plugins/authlogic/lib/authlogic/acts_as_authentic/session_maintenance.rb:113:in `create_session' ./vendor/plugins/authlogic/lib/authlogic/acts_as_authentic/session_maintenance.rb:103:in `maintain_sessions' ./features/step_definitions/user_steps.rb:5:in `/^a valid user record for ([\w]*)$/' features/authorization.feature:5:in `Given a valid user record for joe_runner' Scenario: Jonathan can edit his profile but not other users profiles # features/authorization.feature:7 Given jonathan is logged in as an user # features/step_definitions/user_steps.rb:13 When I go to my user edit page # features/step_definitions/web_steps.rb:18 And I press "Update" # features/step_definitions/web_steps.rb:22 Then I should see "Account updated!" # features/step_definitions/web_steps.rb:142 When I go to joe_runner's user edit page # features/step_definitions/web_steps.rb:18 Then I should see "You do not allowed to access to view that page" # features/step_definitions/web_steps.rb:142 Failing Scenarios: cucumber features/authentication.feature:9 # Scenario: Signup cucumber features/authorization.feature:7 # Scenario: Jonathan can edit his profile but not other users profiles 2 scenarios (2 failed) 15 steps (2 failed, 13 skipped) 0m0.173s rake aborted! Command failed with status (1): [/System/Library/Frameworks/Ruby.framework/...] /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:995:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:in `call' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1010:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1094:in `sh' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1029:in `ruby' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1094:in `ruby' /Library/Ruby/Gems/1.8/gems/cucumber-0.6.4/lib/cucumber/rake/task.rb:68:in `run' /Library/Ruby/Gems/1.8/gems/cucumber-0.6.4/lib/cucumber/rake/task.rb:138:in `define_task' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' /Library/Ruby/Gems/1.8/gems/rake-0.8.7/bin/rake:31 /usr/bin/rake:19:in `load' /usr/bin/rake:19 activespoon:base_project jspooner$ There are a couple of blogs that give examples on how to test facebook apps with cucumber but they didn't help because my error comes before these. http://opensoul.org/2009/3/6/testing-facebook-with-cucumber http://ryanbigg.com/2010/03/testing-facebook/

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  • How to refresh DataGrid and DropDown on main page after hiding modal popup

    - by James
    Hi, I am adding records to a database from a modal popup. After hiding the modal popup, the page has not been refreshed even though I have Rebound the controls. I have reviewed a few postings on the web about this but the solution still evades me. I have attached my code after removing some of the extra detail... It seems I need to cause a postback but I don't know what needs to be changed. Some posts have talked about the extender being misplaced. Anyway, thank you James <asp:Content ID="Content1" ContentPlaceHolderID="Head" Runat="Server"> <div class="divBorder"> <asp:DataGrid id="dgrSessionFolders" runat="server" BorderWidth="2px" BorderStyle="Solid" BorderColor="#C0C0FF" Font-Names="Arial" Font-Bold="True" Font-Size="8pt" GridLines="Horizontal" AutoGenerateColumns="False" PageSize="9999" AllowPaging="False" OnItemCommand="dgrSessionFolders_Command" OnItemDataBound="CheckSessionFolderStatus" HorizontalAlign="Left" ForeColor="Blue" ShowFooter="True" CellPadding="2" OnSortCommand="dgrSessionFolders_Sort" AllowSorting="True"> </asp:DataGrid> </div> &nbsp;&nbsp;&nbsp; <asp:Label ID="Errormsg" runat="server" ForeColor="#CC0000"></asp:Label> <asp:UpdatePanel ID="UpdatePanel1" runat="server" RenderMode="Inline" ChildrenAsTriggers="false" UpdateMode="Conditional"> <Triggers> <asp:AsyncPostBackTrigger ControlID="btnEditTopic" /> <asp:AsyncPostBackTrigger ControlID="btnAdd" /> <asp:AsyncPostBackTrigger ControlID="btnUpdate" /> <asp:AsyncPostBackTrigger ControlID="btnDelete" /> <asp:AsyncPostBackTrigger ControlID="btnClear" /> <asp:AsyncPostBackTrigger ControlID="btnAddTopic" /> <asp:AsyncPostBackTrigger ControlID="btnUpdateTopic" /> <asp:AsyncPostBackTrigger ControlID="btnDeleteTopic" /> </Triggers> <ContentTemplate> <asp:panel id="pnl" runat="server" HorizontalAlign="Center" Height="48px" Width="100%" > &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <asp:ImageButton ID="btnEditTopic" runat="server" AlternateText="Edit Topic" ImageUrl="~/App_Themes/Common/images/BtnEditTopic.jpg" Height="28px"> </asp:ImageButton> <cc1:ModalPopupExtender ID="btnEditTopic_ModalPopupExtender" runat="server" BackgroundCssClass="modalBackground" DropShadow="true" Enabled="true" PopupControlID="pnlEditTopic" TargetControlID="btnEditTopicHidden" CancelControlID="btnEditTopicClose"> </cc1:ModalPopupExtender> <asp:ImageButton ID="btnAdd" runat="server" AlternateText="Add Folder" ImageUrl="~/App_Themes/Common/images/BtnAddFolder.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="btnUpdate" runat="server" AlternateText="Update Folder" ImageUrl="~/App_Themes/Common/images/BtnUpdateFolder.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="btnDelete" runat="server" AlternateText="Delete Folder" ImageUrl="~/App_Themes/Common/images/BtnDeleteFolder.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="BtnClear" runat="server" AlternateText="Clear Screen Input Fields" ImageUrl="~/App_Themes/Common/images/BtnAddMode.jpg" Height="28px"> </asp:ImageButton> <asp:Button ID="btnEditTopicHidden" runat="server" Enabled="false" Text="" Style="visibility: hidden" /> </asp:panel> <asp:Panel ID="pnlEditTopic" runat="server" CssClass="modalPopupEditTopic" Style="display: none;" > <table cellspacing="0" class="borderTable0" width="100%" style=""> <tr> <td colspan="10" class="Subhdr" align="center" style="width:100%"> <asp:label id="lblTopicScreenHdr" Cssclass="ScreenHdr" runat="server">Topic Maintenance</asp:label> </td> </tr> <tr> <td colspan="6"> <asp:Label ID="TopicPopErrorMsg" runat="server" ForeColor="#CC0000">&nbsp;</asp:Label> </td> </tr> <tr style="height:4px"> <td colspan="6" align="center"> <asp:ImageButton ID="btnAddTopic" runat="server" AlternateText="Add Topic" ImageUrl="~/App_Themes/Common/images/BtnApply.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="btnUpdateTopic" runat="server" AlternateText="Update Topic" ImageUrl="~/App_Themes/Common/images/BtnApply.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="btnDeleteTopic" runat="server" AlternateText="Delete Topic" ImageUrl="~/App_Themes/Common/images/BtnDelete.jpg" Height="28px"> </asp:ImageButton> <asp:ImageButton ID="btnEditTopicClose" runat="server" AlternateText="Close Edit Topic Popup" ImageUrl="~/App_Themes/Common/images/BtnCancel.jpg" Height="28px"> </asp:ImageButton> </td> </tr> </table> </asp:Panel> </ContentTemplate> </asp:UpdatePanel> Private Sub btnAddTopic_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAddTopic.Click 'Add the Topic table entry AddTopic() 'Display an informational message Errormsg.Text = "The Topic has been successfully added, thank you! " Errormsg.ForeColor = Drawing.Color.Blue 'Rebind the Topic Drop Down and set to added Topic ddlSessionTopic.DataBind() ddlSessionTopic.SelectedValue = drTopic("TOPC_ID") 'Rebind the Session Folders grid RebindGrid() 'Hide the Topic Popup btnEditTopic_ModalPopupExtender.Hide() End Sub Private Sub RebindGrid() cnnSQL = New SqlConnection(strConnection) cmdSQL = New SqlCommand("GetSessionFoldersForGrid", cnnSQL) cmdSQL.CommandType = CommandType.StoredProcedure cmdSQL.Parameters.Clear() cnnSQL.Open() dadSQL = New SqlDataAdapter(cmdSQL) dadSQL.SelectCommand = cmdSQL dadSQL.Fill(dtSessionFolderGrid) cnnSQL.Close() dvSessionFolderGrid = dtSessionFolderGrid.DefaultView dvSessionFolderGrid.Sort = String.Format("{0} {1}{2}", so.Sortfield, so.SortDirection, so.SortSuffix) dgrSessionFolders.DataSource = dvSessionFolderGrid dgrSessionFolders.DataBind() End Sub

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  • need to print 5 column list in alpha order, vertically

    - by Brad
    Have a webpage that will be viewed by mainly IE users, so CSS3 is out of the question. I want it to list like: A D G B E H C F I Here is the function that currently lists like: A B C D E F G H I function listPhoneExtensions($group,$group_title) { $adldap = new adLDAP(); $group_membership = $adldap->group_members(strtoupper($group),FALSE); sort($group_membership); print " <a name=\"".strtolower($group_title)."\"></a> <h2>".$group_title."</h2> <ul class=\"phone-extensions\">"; foreach ($group_membership as $i => $username) { $userinfo = $adldap->user_info($username, array("givenname","sn","telephonenumber")); $displayname = "<span class=\"name\">".substr($userinfo[0]["sn"][0],0,9).", ".substr($userinfo[0]["givenname"][0],0,9)."</span><span class=\"ext\">".$userinfo[0]["telephonenumber"][0]."</span>"; if($userinfo[0]["sn"][0] != "" && $userinfo[0]["givenname"][0] != "" && $userinfo[0]["telephonenumber"][0] != "") { print "<li>".$displayname."</li>"; } } print "</ul><p class=\"clear-both\"><a href=\"#top\" class=\"link-to-top\">&uarr; top</a></p>"; } Example rendered html: <ul class="phone-extensions"> <li><span class="name">Barry Bonds</span><span class="ext">8281</span></li> <li><span class="name">Gerald Clark</span><span class="ext">8211</span></li> <li><span class="name">Juan Dixon</span><span class="ext">8282</span></li> <li><span class="name">Omar Ebbs</span><span class="ext">8252</span></li> <li><span class="name">Freddie Flank</span><span class="ext">2281</span></li> <li><span class="name">Jerry Gilmore</span><span class="ext">4231</span></li> <li><span class="name">Kim Moore</span><span class="ext">5767</span></li> <li><span class="name">Barry Bonds</span><span class="ext">8281</span></li> <li><span class="name">Gerald Clark</span><span class="ext">8211</span></li> <li><span class="name">Juan Dixon</span><span class="ext">8282</span></li> <li><span class="name">Omar Ebbs</span><span class="ext">8252</span></li> <li><span class="name">Freddie Flank</span><span class="ext">2281</span></li> <li><span class="name">Jerry Gilmore</span><span class="ext">4231</span></li> <li><span class="name">Kim Moore</span><span class="ext">5767</span></li> <li><span class="name">Barry Bonds</span><span class="ext">8281</span></li> <li><span class="name">Gerald Clark</span><span class="ext">8211</span></li> <li><span class="name">Juan Dixon</span><span class="ext">8282</span></li> <li><span class="name">Omar Ebbs</span><span class="ext">8252</span></li> <li><span class="name">Freddie Flank</span><span class="ext">2281</span></li> <li><span class="name">Jerry Gilmore</span><span class="ext">4231</span></li> <li><span class="name">Kim Moore</span><span class="ext">5767</span></li> </ul> Any help is appreciated to getting it to list alpha vertically.

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  • Displaytag export option is not working

    - by Nirmal
    Hello All, I am using Displaytag framework for pagination & exporting purpose. In that i am also using Strut2Tiles Integration. Whenever i am calling any action class it will returning me a list & through Displaytag i am successfully displaying record on my page. For that my jsp page's code looks like : <s:set name="selectedPageSize" value="selectedPageSize" scope="request"/> <s:set value="accountList" scope="request" name="accountList"/> <display:table name="accountList" export="true" class="table" requestURI="" id="accountList" pagesize="${selectedPageSize}" > <display:setProperty name="export.pdf" value="true" /> <display:column property="id" sortable="true" class="sort-title"/> <display:column property="name" sortable="true"/> <display:column property="contactPerson" sortable="true"/> <display:column property="phone1" sortable="true"/> <display:column property="phone2" sortable="true"/> <display:column property="fax" sortable="true"/> <display:column property="email" sortable="true"/> <display:column property="webSite" sortable="true"/> <display:column property="address1" sortable="true"/> <display:column property="address2" sortable="true"/> <display:column property="countryId.name" title="Country" sortable="true"/> <display:column property="stateId.name" title="State" sortable="true"/> <display:column property="countryId.name" title="City" sortable="true"/> <display:column property="isDeleted" sortable="true"/> <display:column title="Delete"> <s:url id="removeUrl" action="finance/deleteAccount.action"> <s:param name="id" value="#attr.accountList.id" /> </s:url> <s:a href="%{removeUrl}" theme="ajax" targets="accountList">Remove</s:a> </display:column> <display:column title="Update"> <s:url id="updateUrl" action="finance/updateAccount.action"> <s:param value="#attr.accountList.id" name="id"/> </s:url> <s:a href="%{updateUrl}&action=update" targets="accountlist">Update</s:a> </display:column> Actually this page is displaying through tiles configuration. Here i have enabled the export option, so it is showing me the exporting options like CSV, EXCEL, XML. But whenver i am clicking on that CSV link, my web browser hanged, means nothing is displayed on it For that exporting solution i have also added filter in my web.xml. My web.xml looks like: <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter> <filter-name>ResponseOverrideFilter</filter-name> <filter-class>org.displaytag.filter.ResponseOverrideFilter</filter-class> </filter> <filter-mapping> <filter-name>ResponseOverrideFilter</filter-name> <url-pattern>*.action</url-pattern> </filter-mapping> <filter-mapping> <filter-name>ResponseOverrideFilter</filter-name> <url-pattern>*.jsp</url-pattern> </filter-mapping> <listener> <listener-class>org.apache.struts2.tiles.StrutsTilesListener</listener-class> </listener> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/classes/webApplicationContext.xml</param-value> </context-param> <welcome-file-list> <welcome-file>jsp/welcome.jsp</welcome-file> </welcome-file-list> I have also included following list of libraries of displaytag : 1) displaytag-1.2.jar 2) displaytag-export-poi-1.2.jar 3) displaytag-portlet-1.2.jar The exception that i am getting is : 2009-05-09 12:02:38,234 DEBUG (org.displaytag.tags.TableTag:1524) - Exportfilter NOT enabled 2009-05-09 12:02:38,312 WARN (org.displaytag.tags.TableTag:63) - Exception: [.TableTag] Unable to reset response before returning exported data. You are not using an export filter. Be sure that no other jsp tags are used before display:table or refer to the displaytag documentation on how to configure the export filter (requires j2ee 1.3). ApplicationDispatcher[/PaginationTry2] PWC1231: Servlet.service() for servlet jsp threw exception Exception: [.TableTag] Unable to reset response before returning exported data. You are not using an export filter. Be sure that no other jsp tags are used before display:table or refer to the displaytag documentation on how to configure the export filter (requires j2ee 1.3). Plz reply, i am stuck with this problem.

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  • Problem deploying servlets in JBoss 5.1 on eclipse.

    - by Jeremy Goodell
    Yesterday I created a simple image servlet and attempted to deploy it. I am getting an error on JBoss startup, and then further errors on trying to invoke the servlet. I spent about 8 hours yesterday searching the web for answers and trying different scenarios. I ended up making my JBoss problems worse and then fixing them, but I never did get the servlet to work. The servlet is com.controller.MyImageServlet, and looks like this: package com.controller; import javax.servlet.http.*; /** * Servlet implementation class MyImageServlet */ public class MyImageServlet extends HttpServlet { private static final long serialVersionUID = 1L; public MyImageServlet() { super(); } // Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* ... */ } } The tags I've added to web.xml looks like this: <servlet> <servlet-name>ImageServlet</servlet-name> <servlet-class>com.controller.MyImageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ImageServlet</servlet-name> <url-pattern>/CERTIMAGE/*</url-pattern> </servlet-mapping> On server startup, this is the only indication in the log that something is amiss: 01:59:25,328 WARN [JAXWSDeployerHookPreJSE] Cannot load servlet class: com.controller.MyImageServlet When I try the URL pattern (http://localhost:9980/CERTIMAGE/1), I get the following stack trace in the log (and in the Browser): 01:59:39,640 INFO [[/]] Marking servlet ImageServlet as unavailable 01:59:39,640 ERROR [[ImageServlet]] Allocate exception for servlet ImageServlet java.lang.ClassNotFoundException: com.controller.MyImageServlet at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:262) at org.jboss.web.tomcat.service.TomcatInjectionContainer.newInstance(TomcatInjectionContainer.java:256) at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1006) at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:777) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:619) If I try the URL pattern again, I get the following message in the log: 09:33:32,390 INFO [[ImageServlet]] Servlet ImageServlet is currently unavailable I have verified that MyImageServlet.class is in the WAR at WEB-INF/classes/com/controller/images. As a matter of fact, I even added some code to one of my JSPs to attempt to instantiate the Servlet and call the doGet method. This actually works and outputs the correct debug sequences to the log indicating that the Servlet constructor and doGet methods were called. I also tried following some instructions for creating/deploying a very simple HelloWorld servlet, and that has exactly the same problem. Note that web.xml already contained a servlet put there by JBoss: org.jboss.web.tomcat.service.StatusServlet -- that Servlet does not give any errors in the log. As an experiment, I removed ".web" from that path and ended up getting exactly the same error as I'm getting on my Servlet. So it would appear that JBoss is not able to locate my Servlet given the specified path. Just for kicks, I've tried all sorts of other paths, like just plain MyImageServlet, controller.MyImageServlet, and more. Also, the servlet was originally named ImageServlet, but I attempted the name change thinking maybe there was some conflict with an existing ImageServlet. In all cases, the behavior is the same. After all of my research yesterday, I would say that this appears to be a problem with the JBoss servlet container, and I also learned that JBoss 5.1.0.GA should come bundled with a tomcat servlet container. I installed JBoss on my PC (Windows XP) myself less than 2 months ago (from jboss.org) and used it pretty much as is. Note that I am running on JDK 1.6, so I did use the jboss-jdk6 installation version. I am running on Windows, but I also deploy to a Linux virtual dedicated server. I deployed the current version of my program, including the servlet to the Linux box, but I get the exact same errors. I'm reluctant to just try reinstalling JBoss, since it's hard to place the blame on the JBoss installation when I get the same errors on two completely different installations. I am a bit suspicious of the bundled tomcat servlet container, because using eclipse, I haven't been able to locate any indication that there is a tomcat bundled into JBoss. I did locate servlet-api.jar in the JBoss common/lib directory. This is on the eclipse build path. One possibly useful note: I had previously used a standalone tomcat server for other projects using the same eclipse, so maybe it's some sort of eclipse issue? But, as I said, I do get the same errors when I deploy to the Linux server, and that deployment process just involves ftping files to the server and then putting them into the deployed war package and restarting JBoss. Thanks for any help you can provide.

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  • What add-in/workbench framework is the best .NET alternative to Eclipse RCP?

    - by Winston Fassett
    I'm looking for a plugin-based application framework that is comparable to the Eclipse Plugin Framework, which to my simple mind consists of: a core plugin management framework (Equinox / OSGI), which provides the ability to declare extension endpoints and then discover and load plugins that service those endpoints. (this is different than Dependency Injection, but admittedly the difference is subtle - configuration is highly de-centralized, there are versioning concerns, it might involve an online plugin repository, and most importantly to me, it should be easy for the user to add plugins without needing to know anything about the underlying architecture / config files) many layers of plugins that provide a basic workbench shell with concurrency support, commands, preference sheets, menus, toolbars, key bindings, etc. That is just scratching the surface of the RCP, which itself is meant to serve as the foundation of your application, which you build by writing / assembling even more plugins. Here's what I've gleaned from the internet in the past couple of days... As far as I can tell, there is nothing in the .NET world that remotely approaches the robustness and maturity of the Eclipse RCP for Java but there are several contenders that do either #1 or #2 pretty well. (I should also mention that I have not made a final decision on WinForms vs WPF, so I'm also trying to understand the level of UI coupling in any candidate framework. I'm also wondering about platform coupling and source code licensing) I must say that the open-source stuff is generally less-documented but easier to understand, while the MS stuff typically has more documentation but is less accessible, so that with many of the MS technologies, I'm left wondering what they actually do, in a practical sense. These are the libraries I have found: SharpDevelop The first thing I looked at was SharpDevelop, which does both #1 and also #2 in a basic way (no insult to SharpDevelop, which is admirable - I just mean more basic than Eclipse RCP). However, SharpDevelop is an application more than a framework, and there are basic assumptions and limitations there (i.e. being somewhat coupled to WinForms). Still, there are some articles on CodeProject explaining how to use it as the foundation for an application. System.Addins It appears that System.Addins is meant to provide a robust add-in loading framework, with some sophisticated options for loading assemblies with varying levels of trusts and even running the out of process. It appears to be primarily code-based, and pretty code-heavy, with lots of assemblies that serve to insulate against versioning issues., using Guidance Automation to generate a good deal of code. So far I haven't found many System.AddIns articles that illustrate how it could be used to build something like an Eclipse RCP, and many people seem to be wringing their hands about its complexity. Mono.Addins It appears that Mono.Addins was influenced by System.Addins, SharpDevelop, and MonoDevelop. It seems to provide the basics from System.Addins, with less sophisticated options for plugin loading, but more simplicity, with attribute-based registration, XML manifests, and the infrastructure for online plugin repositories. It has a pretty good FAQ and documentation, as well as a fairly robust set of examples that really help paint a picture of how to develop an architecture like that of SharpDevelop or Eclipse. The examples use GTK for UI, but the framework itself is not coupled to GTK. So it appears to do #1 (add-in loading) pretty well and points the way to #2 (workbench framework). It appears that Mono.Addins was derived from MonoDevelop, but I haven't actually looked at whether MonoDevelop provides a good core workbench framework. Managed Extensibility Framework This is what everyone's talking about at the moment, and it's slowly getting clearer what it does, but I'm still pretty fuzzy, even after reading several posts on SO. The official word is that it "can live side-by-side" with System.Addins. However, it doesn't reference it and it appears to reproduce some of its functionality. It seems to me, then, that it is a simpler, more accessible alternative to System.Addins. It appears to be more like Mono.Addins in that it provides attribute-based wiring. It provides "catalogs" that can be attribute-based or directory-based. It does not seem to provide any XML or manifest-based wiring. So far I haven't found much documentation and the examples seem to be kind of "magical" and more reminiscent of attribute-based DI, despite the clarifications that MEF is not a DI container. Its license just got opened up, but it does reference WindowsBase -- not sure if that means it's coupled to Windows. Acropolis I'm not sure what this is. Is it MEF, or something that is still coming? Composite Application Blocks There are WPF and Winforms Composite Application blocks that seem to provide much more of a workbench framework. I have very little experience with these but they appear to rely on Guidance Automation quite a bit are obviously coupled with the UI layers. There are a few examples of combining MEF with these application blocks. I've done the best I could to answer my own question here, but I'm really only scratching the surface, and I don't have experience with any of these frameworks. Hopefully some of you can add more detail about the frameworks you have experience with. It would be great if we could end up with some sort of comparison matrix.

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  • I don't get prices with Amazon Product Advertising API

    - by Xarem
    I try to get prices of an ASIN number with the Amazon Product Advertising API. Code: $artNr = "B003TKSD8E"; $base_url = "http://ecs.amazonaws.de/onca/xml"; $params = array( 'AWSAccessKeyId' => self::API_KEY, 'AssociateTag' => self::API_ASSOCIATE_TAG, 'Version' => "2010-11-01", 'Operation' => "ItemLookup", 'Service' => "AWSECommerceService", 'Condition' => "All", 'IdType' => 'ASIN', 'ItemId' => $artNr); $params['Timestamp'] = gmdate("Y-m-d\TH:i:s.\\0\\0\\0\\Z", time()); $url_parts = array(); foreach(array_keys($params) as $key) $url_parts[] = $key . "=" . str_replace('%7E', '~', rawurlencode($params[$key])); sort($url_parts); $url_string = implode("&", $url_parts); $string_to_sign = "GET\necs.amazonaws.de\n/onca/xml\n" . $url_string; $signature = hash_hmac("sha256", $string_to_sign, self::API_SECRET, TRUE); $signature = urlencode(base64_encode($signature)); $url = $base_url . '?' . $url_string . "&Signature=" . $signature; $response = file_get_contents($url); $parsed_xml = simplexml_load_string($response); I think this should be correct - but I don't get offers in the response: SimpleXMLElement Object ( [OperationRequest] => SimpleXMLElement Object ( [RequestId] => ************************* [Arguments] => SimpleXMLElement Object ( [Argument] => Array ( [0] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Condition [Value] => All ) ) [1] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Operation [Value] => ItemLookup ) ) [2] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Service [Value] => AWSECommerceService ) ) [3] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => ItemId [Value] => B003TKSD8E ) ) [4] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => IdType [Value] => ASIN ) ) [5] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => AWSAccessKeyId [Value] => ************************* ) ) [6] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Timestamp [Value] => 2011-11-29T01:32:12.000Z ) ) [7] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Signature [Value] => ************************* ) ) [8] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => AssociateTag [Value] => ************************* ) ) [9] => SimpleXMLElement Object ( [@attributes] => Array ( [Name] => Version [Value] => 2010-11-01 ) ) ) ) [RequestProcessingTime] => 0.0091540000000000 ) [Items] => SimpleXMLElement Object ( [Request] => SimpleXMLElement Object ( [IsValid] => True [ItemLookupRequest] => SimpleXMLElement Object ( [Condition] => All [IdType] => ASIN [ItemId] => B003TKSD8E [ResponseGroup] => Small [VariationPage] => All ) ) [Item] => SimpleXMLElement Object ( [ASIN] => B003TKSD8E [DetailPageURL] => http://www.amazon.de/Apple-iPhone-4-32GB-schwarz/dp/B003TKSD8E%3FSubscriptionId%3DAKIAI6NFQHK2DQIPRUEQ%26tag%3Dbanholzerme-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB003TKSD8E [ItemLinks] => SimpleXMLElement Object ( [ItemLink] => Array ( [0] => SimpleXMLElement Object ( [Description] => Add To Wishlist [URL] => http://www.amazon.de/gp/registry/wishlist/add-item.html%3Fasin.0%3DB003TKSD8E%26SubscriptionId%3DAKIAI6NFQHK2DQIPRUEQ%26tag%3Dbanholzerme-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D12738%26creativeASIN%3DB003TKSD8E ) [1] => SimpleXMLElement Object ( [Description] => Tell A Friend [URL] => http://www.amazon.de/gp/pdp/taf/B003TKSD8E%3FSubscriptionId%3DAKIAI6NFQHK2DQIPRUEQ%26tag%3Dbanholzerme-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D12738%26creativeASIN%3DB003TKSD8E ) [2] => SimpleXMLElement Object ( [Description] => All Customer Reviews [URL] => http://www.amazon.de/review/product/B003TKSD8E%3FSubscriptionId%3DAKIAI6NFQHK2DQIPRUEQ%26tag%3Dbanholzerme-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D12738%26creativeASIN%3DB003TKSD8E ) [3] => SimpleXMLElement Object ( [Description] => All Offers [URL] => http://www.amazon.de/gp/offer-listing/B003TKSD8E%3FSubscriptionId%3DAKIAI6NFQHK2DQIPRUEQ%26tag%3Dbanholzerme-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D12738%26creativeASIN%3DB003TKSD8E ) ) ) [ItemAttributes] => SimpleXMLElement Object ( [Manufacturer] => Apple Computer [ProductGroup] => CE [Title] => Apple iPhone 4 32GB schwarz ) ) ) ) Can someone please explain me why I don't get any price-information? Thank you very much

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  • Asp.Net MVC and ajax async callback execution order

    - by lrb
    I have been sorting through this issue all day and hope someone can help pinpoint my problem. I have created a "asynchronous progress callback" type functionality in my app using ajax. When I strip the functionality out into a test application I get the desired results. See image below: Desired Functionality When I tie the functionality into my single page application using the same code I get a sort of blocking issue where all requests are responded to only after the last task has completed. In the test app above all request are responded to in order. The server reports a ("pending") state for all requests until the controller method has completed. Can anyone give me a hint as to what could cause the change in behavior? Not Desired Desired Fiddler Request/Response GET http://localhost:12028/task/status?_=1383333945335 HTTP/1.1 X-ProgressBar-TaskId: 892183768 Accept: */* X-Requested-With: XMLHttpRequest Referer: http://localhost:12028/ Accept-Language: en-US Accept-Encoding: gzip, deflate User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0) Connection: Keep-Alive DNT: 1 Host: localhost:12028 HTTP/1.1 200 OK Cache-Control: private Content-Type: text/html; charset=utf-8 Vary: Accept-Encoding Server: Microsoft-IIS/8.0 X-AspNetMvc-Version: 3.0 X-AspNet-Version: 4.0.30319 X-SourceFiles: =?UTF-8?B?QzpcUHJvamVjdHNcVEVNUFxQcm9ncmVzc0Jhclx0YXNrXHN0YXR1cw==?= X-Powered-By: ASP.NET Date: Fri, 01 Nov 2013 21:39:08 GMT Content-Length: 25 Iteration completed... Not Desired Fiddler Request/Response GET http://localhost:60171/_Test/status?_=1383341766884 HTTP/1.1 X-ProgressBar-TaskId: 838217998 Accept: */* X-Requested-With: XMLHttpRequest Referer: http://localhost:60171/Report/Index Accept-Language: en-US Accept-Encoding: gzip, deflate User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0) Connection: Keep-Alive DNT: 1 Host: localhost:60171 Pragma: no-cache Cookie: ASP.NET_SessionId=rjli2jb0wyjrgxjqjsicdhdi; AspxAutoDetectCookieSupport=1; TTREPORTS_1_0=CC2A501EF499F9F...; __RequestVerificationToken=6klOoK6lSXR51zCVaDNhuaF6Blual0l8_JH1QTW9W6L-3LroNbyi6WvN6qiqv-PjqpCy7oEmNnAd9s0UONASmBQhUu8aechFYq7EXKzu7WSybObivq46djrE1lvkm6hNXgeLNLYmV0ORmGJeLWDyvA2 HTTP/1.1 200 OK Cache-Control: private Content-Type: text/html; charset=utf-8 Vary: Accept-Encoding Server: Microsoft-IIS/8.0 X-AspNetMvc-Version: 4.0 X-AspNet-Version: 4.0.30319 X-SourceFiles: =?UTF-8?B?QzpcUHJvamVjdHNcSUxlYXJuLlJlcG9ydHMuV2ViXHRydW5rXElMZWFybi5SZXBvcnRzLldlYlxfVGVzdFxzdGF0dXM=?= X-Powered-By: ASP.NET Date: Fri, 01 Nov 2013 21:37:48 GMT Content-Length: 25 Iteration completed... The only difference in the two requests headers besides the auth tokens is "Pragma: no-cache" in the request and the asp.net version in the response. Thanks Update - Code posted (I probably need to indicate this code originated from an article by Dino Esposito ) var ilProgressWorker = function () { var that = {}; that._xhr = null; that._taskId = 0; that._timerId = 0; that._progressUrl = ""; that._abortUrl = ""; that._interval = 500; that._userDefinedProgressCallback = null; that._taskCompletedCallback = null; that._taskAbortedCallback = null; that.createTaskId = function () { var _minNumber = 100, _maxNumber = 1000000000; return _minNumber + Math.floor(Math.random() * _maxNumber); }; // Set progress callback that.callback = function (userCallback, completedCallback, abortedCallback) { that._userDefinedProgressCallback = userCallback; that._taskCompletedCallback = completedCallback; that._taskAbortedCallback = abortedCallback; return this; }; // Set frequency of refresh that.setInterval = function (interval) { that._interval = interval; return this; }; // Abort the operation that.abort = function () { // if (_xhr !== null) // _xhr.abort(); if (that._abortUrl != null && that._abortUrl != "") { $.ajax({ url: that._abortUrl, cache: false, headers: { 'X-ProgressBar-TaskId': that._taskId } }); } }; // INTERNAL FUNCTION that._internalProgressCallback = function () { that._timerId = window.setTimeout(that._internalProgressCallback, that._interval); $.ajax({ url: that._progressUrl, cache: false, headers: { 'X-ProgressBar-TaskId': that._taskId }, success: function (status) { if (that._userDefinedProgressCallback != null) that._userDefinedProgressCallback(status); }, complete: function (data) { var i=0; }, }); }; // Invoke the URL and monitor its progress that.start = function (url, progressUrl, abortUrl) { that._taskId = that.createTaskId(); that._progressUrl = progressUrl; that._abortUrl = abortUrl; // Place the Ajax call _xhr = $.ajax({ url: url, cache: false, headers: { 'X-ProgressBar-TaskId': that._taskId }, complete: function () { if (_xhr.status != 0) return; if (that._taskAbortedCallback != null) that._taskAbortedCallback(); that.end(); }, success: function (data) { if (that._taskCompletedCallback != null) that._taskCompletedCallback(data); that.end(); } }); // Start the progress callback (if any) if (that._userDefinedProgressCallback == null || that._progressUrl === "") return this; that._timerId = window.setTimeout(that._internalProgressCallback, that._interval); }; // Finalize the task that.end = function () { that._taskId = 0; window.clearTimeout(that._timerId); } return that; };

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  • Overly accessible and incredibly resource hungry relationships between business objects. How can I f

    - by Mike
    Hi, Firstly, This might seem like a long question. I don't think it is... The code is just an overview of what im currently doing. It doesn't feel right, so I am looking for constructive criticism and warnings for pitfalls and suggestions of what I can do. I have a database with business objects. I need to access properties of parent objects. I need to maintain some sort of state through business objects. If you look at the classes, I don't think that the access modifiers are right. I don't think its structured very well. Most of the relationships are modelled with public properties. SubAccount.Account.User.ID <-- all of those are public.. Is there a better way to model a relationship between classes than this so its not so "public"? The other part of this question is about resources: If I was to make a User.GetUserList() function that returns a List, and I had 9000 users, when I call the GetUsers method, it will make 9000 User objects and inside that it will make 9000 new AccountCollection objects. What can I do to make this project not so resource hungry? Please find the code below and rip it to shreds. public class User { public string ID {get;set;} public string FirstName {get; set;} public string LastName {get; set;} public string PhoneNo {get; set;} public AccountCollection accounts {get; set;} public User { accounts = new AccountCollection(this); } public static List<Users> GetUsers() { return Data.GetUsers(); } } public AccountCollection : IEnumerable<Account> { private User user; public AccountCollection(User user) { this.user = user; } public IEnumerable<Account> GetEnumerator() { return Data.GetAccounts(user); } } public class Account { public User User {get; set;} //This is public so that the subaccount can access its Account's User's ID public int ID; public string Name; public Account(User user) { this.user = user; } } public SubAccountCollection : IEnumerable<SubAccount> { public Account account {get; set;} public SubAccountCollection(Account account) { this.account = account; } public IEnumerable<SubAccount> GetEnumerator() { return Data.GetSubAccounts(account); } } public class SubAccount { public Account account {get; set;} //this is public so that my Data class can access the account, to get the account's user's ID. public SubAccount(Account account) { this.account = account; } public Report GenerateReport() { Data.GetReport(this); } } public static class Data { public static List<Account> GetSubAccounts(Account account) { using (var dc = new databaseDataContext()) { List<SubAccount> query = (from a in dc.Accounts where a.UserID == account.User.ID //this is getting the account's user's ID select new SubAccount(account) { ID = a.ID, Name = a.Name, }).ToList(); } } public static List<Account> GetAccounts(User user) { using (var dc = new databaseDataContext()) { List<Account> query = (from a in dc.Accounts where a.UserID == User.ID //this is getting the user's ID select new Account(user) { ID = a.ID, Name = a.Name, }).ToList(); } } public static Report GetReport(SubAccount subAccount) { Report report = new Report(); //database access code here //need to get the user id of the subaccount's account for data querying. //i've got the subaccount, but how should i get the user id. //i would imagine something like this: int accountID = subAccount.Account.User.ID; //but this would require the subaccount's Account property to be public. //i do not want this to be accessible from my other project (UI). //reading up on internal seems to do the trick, but within my code it still feels //public. I could restrict the property to read, and only private set. return report; } public static List<User> GetUsers() { using (var dc = new databaseDataContext()) { var query = (from u in dc.Users select new User { ID = u.ID, FirstName = u.FirstName, LastName = u.LastName, PhoneNo = u.PhoneNo }).ToList(); return query; } } }

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  • Accessing py2exe program over network in Windows 98 throws ImportErrors

    - by darvids0n
    I'm running a py2exe-compiled python program from one server machine on a number of client machines (mapped to a network drive on every machine, say W:). For Windows XP and later machines, have so far had zero problems with Python picking up W:\python23.dll (yes, I'm using Python 2.3.5 for W98 compatibility and all that). It will then use W:\zlib.pyd to decompress W:\library.zip containing all the .pyc files like os and such, which are then imported and the program runs no problems. The issue I'm getting is on some Windows 98 SE machines (note: SOME Windows 98 SE machines, others seem to work with no apparent issues). What happens is, the program runs from W:, the W:\python23.dll is, I assume, found (since I'm getting Python ImportErrors, we'd need to be able to execute a Python import statement), but a couple of things don't work: 1) If W:\library.zip contains the only copy of the .pyc files, I get ZipImportError: can't decompress data; zlib not available (nonsense, considering W:\zlib.pyd IS available and works fine with the XP and higher machines on the same network). 2) If the .pyc files are actually bundled INSIDE the python exe by py2exe, OR put in the same directory as the .exe, OR put into a named subdirectory which is then set as part of the PYTHONPATH variable (e.g W:\pylib), I get ImportError: no module named os (os is the first module imported, before sys and anything else). Come to think of it, sys.path wouldn't be available to search if os was imported before it maybe? I'll try switching the order of those imports but my question still stands: Why is this a sporadic issue, working on some networks but not on others? And how would I force Python to find the files that are bundled inside the very executable I run? I have immediate access to the working Windows 98 SE machine, but I only get access to the non-working one (a customer of mine) every morning before their store opens. Thanks in advance! EDIT: Okay, big step forward. After debugging with PY2EXE_VERBOSE, the problem occurring on the specific W98SE machine is that it's not using the right path syntax when looking for imports. Firstly, it doesn't seem to read the PYTHONPATH environment variable (there may be a py2exe-specific one I'm not aware of, like PY2EXE_VERBOSE). Secondly, it only looks in one place before giving up (if the files are bundled inside the EXE, it looks there. If not, it looks in library.zip). EDIT 2: In fact, according to this, there is a difference between the sys.path in the Python interpreter and that of Py2exe executables. Specifically, sys.path contains only a single entry: the full pathname of the shared code archive. Blah. No fallbacks? Not even the current working directory? I'd try adding W:\ to PATH, but py2exe doesn't conform to any sort of standards for locating system libraries, so it won't work. Now for the interesting bit. The path it tries to load atexit, os, etc. from is: W:\\library.zip\<module>.<ext> Note the single slash after library.zip, but the double slash after the drive letter (someone correct me if this is intended and should work). It looks like if this is a string literal, then since the slash isn't doubled, it's read as an (invalid) escape sequence and the raw character is printed (giving W:\library.zipos.pyd, W:\library.zipos.dll, ... instead of with a slash); if it is NOT a string literal, the double slash might not be normpath'd automatically (as it should be) and so the double slash confuses the module loader. Like I said, I can't just set PYTHONPATH=W:\\library.zip\\ because it ignores that variable. It may be worth using sys.path.append at the start of my program but hard-coding module paths is an absolute LAST resort, especially since the problem occurs in ONE configuration of an outdated OS. Any ideas? I have one, which is to normpath the sys.path.. pity I need os for that. Another is to just append os.getenv('PATH') or os.getenv('PYTHONPATH') to sys.path... again, needing the os module. The site module also fails to initialise, so I can't use a .pth file. I also recently tried the following code at the start of the program: for pth in sys.path: fErr.write(pth) fErr.write(' to ') pth.replace('\\\\','\\') # Fix Windows 98 pathing issues fErr.write(pth) fErr.write('\n') But it can't load linecache.pyc, or anything else for that matter; it can't actually execute those commands from the looks of things. Is there any way to use built-in functionality which doesn't need linecache to modify the sys.path dynamically? Or am I reduced to hard-coding the correct sys.path?

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  • Listview selects mutliple items when clicked

    - by xlph
    I'm trying to make a task manager, and I only have one problem. I have a listview that gets inflated. All the elements in the listview are correct. The problem is that when I select an item, the listview will select another item away. I've heard listviews repopulate the list as it scrolls down to save memory. I think this may be some sort of problem. Here is a picture of the problem. If i had more apps loaded, then it would continue to select multiple at once. Here is the code of my adapter and activity and XML associated public class TaskAdapter extends BaseAdapter{ private Context mContext; private List<TaskInfo> mListAppInfo; private PackageManager mPack; public TaskAdapter(Context c, List<TaskInfo> list, PackageManager pack) { mContext = c; mListAppInfo = list; mPack = pack; } @Override public int getCount() { return mListAppInfo.size(); } @Override public Object getItem(int position) { return mListAppInfo.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(final int position, View convertView, ViewGroup parent) { TaskInfo entry = mListAppInfo.get(position); if (convertView == null) { LayoutInflater inflater = LayoutInflater.from(mContext); //System.out.println("Setting LayoutInflater in TaskAdapter " +mContext +" " +R.layout.taskinfo +" " +R.id.tmbox); convertView = inflater.inflate(R.layout.taskinfo,null); } ImageView ivIcon = (ImageView)convertView.findViewById(R.id.tmImage); ivIcon.setImageDrawable(entry.getIcon()); TextView tvName = (TextView)convertView.findViewById(R.id.tmbox); tvName.setText(entry.getName()); convertView.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { final CheckBox checkBox = (CheckBox)v.findViewById(R.id.tmbox); if(v.isSelected()) { System.out.println("Listview not selected "); //CK.get(arg2).setChecked(false); checkBox.setChecked(false); v.setSelected(false); } else { System.out.println("Listview selected "); //CK.get(arg2).setChecked(true); checkBox.setChecked(true); v.setSelected(true); } } }); return convertView; public class TaskManager extends Activity implements Runnable { private ProgressDialog pd; private TextView ram; private String s; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.taskpage); setTitleColor(Color.YELLOW); Thread thread = new Thread(this); thread.start(); } @Override public void run() { //System.out.println("In Taskmanager Run() Thread"); final PackageManager pm = getPackageManager(); final ListView box = (ListView) findViewById(R.id.cBoxSpace); final List<TaskInfo> CK = populate(box, pm); runOnUiThread(new Runnable() { @Override public void run() { ram.setText(s); box.setAdapter(new TaskAdapter(TaskManager.this, CK, pm)); //System.out.println("In Taskmanager runnable Run()"); endChecked(CK); } }); handler.sendEmptyMessage(0); } Taskinfo.xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal" android:gravity="center_horizontal"> <ImageView android:id="@+id/tmImage" android:layout_width="48dp" android:layout_height="48dp" android:scaleType="centerCrop" android:adjustViewBounds="false" android:focusable="false" /> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/tmbox" android:lines="2"/> </LinearLayout> Taskpage.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical"> <ListView android:id="@+id/cBoxSpace" android:layout_width="wrap_content" android:layout_height="400dp" android:orientation="vertical"/> <TextView android:id="@+id/RAM" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="18sp" /> <Button android:id="@+id/endButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="End Selected Tasks" /> </LinearLayout> Any ideas for what reason mutliple items are selected with a single click would be GREATLY appreciated. I've been messing around with different implementations and listeners and listadapters but to no avail.

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  • Implementation question involving implementing an interface

    - by Vivin Paliath
    I'm writing a set of collection classes for different types of Trees. I'm doing this as a learning exercise and I'm also hoping it turns out to be something useful. I really want to do this the right way and so I've been reading Effective Java and I've also been looking at the way Joshua Bloch implemented the collection classes by looking at the source. I seem to have a fair idea of what is being done, but I still have a few things to sort out. I have a Node<T> interface and an AbstractNode<T> class that implements the Node interface. I then created a GenericNode<T> (a node that can have 0 to n children, and that is part of an n-ary tree) class that extends AbstractNode<T> and implements Node<T>. This part was easy. Next, I created a Tree<T> interface and an AbstractTree<T> class that implements the Tree<T> interface. After that, I started writing a GenericTree<T> class that extends AbstractTree<T> and implements Tree<T>. This is where I started having problems. As far as the design is concerned, a GenericTree<T> can only consist of nodes of type GenericTreeNode<T>. This includes the root. In my Tree<T> interface I have: public interface Tree<T> { void setRoot(Node<T> root); Node<T> getRoot(); List<Node<T>> postOrder(); ... rest omitted ... } And, AbstractTree<T> implements this interface: public abstract class AbstractTree<T> implements Tree<T> { protected Node<T> root; protected AbstractTree() { } protected AbstractTree(Node<T> root) { this.root = root; } public void setRoot(Node<T> root) { this.root = root; } public Node<T> getRoot() { return this.root; } ... rest omitted ... } In GenericTree<T>, I can have: public GenericTree(Node<T> root) { super(root); } But what this means is that you can create a generic tree using any subtype of Node<T>. You can also set the root of a tree to any subtype of Node<T>. I want to be able to restrict the type of the node to the type of the tree that it can represent. To fix this, I can do this: public GenericTree(GenericNode<T> root) { super(root); } However, setRoot still accepts a parameter of type Node<T>. Which means a user can still create a tree with the wrong type of root node. How do I enforce this constraint? The only way I can think of doing is either: Do an instanceof which limits the check to runtime. I'm not a huge fan of this. Remove setRoot from the interface and have the base class implement this method. This means that it is not part of the contract and anyone who wants to make a new type of tree needs to remember to implement this method. Is there a better way? The second question I have concerns the return type of postOrder which is List<Node<T>>. This means that if a user is operating on a GenericTree<T> object and calls postOrder, he or she receives a list that consists of Node<T> objects. This means when iterating through (using a foreach construct) they would have perform an explicit cast to GenericNode<T> if they want to use methods that are only defined in that class. I don't like having to place this burden on the user. What are my options in this case? I can only think of removing the method from the interface and have the subclass implement this method making sure that it returns a list of appropriate subtype of Node<T>. However, this once again removes it from the contract and it's anyone who wants to create a new type of tree has to remember to implement this method. Is there a better way?

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  • Merging elements inside a xml.etree.ElementTree

    - by theAlse
    I have a huge test data like the one provided below (and yes I have no control over this data). Each line is actually 6 parts and I need to generate an XML based on this data. Nav;Basic;Dest;Smoke;No;Yes; Nav;Dest;Recent;Regg;No;Yes; Nav;Dest;Favourites;Regg;No;Yes; ... Nav;Dest using on board;By POI;Smoke;No;Yes; Nav;Dest using on board;Other;Regg;No;Yes; The first 3 elements on each line denotes "test suites"-XML element and the last 3 element should create a "test case"-XML element. I have successfully converted it into a XML using the following code: # testsuite (root) testsuite = ET.Element('testsuite') testsuite.set("name", "Tests") def _create_testcase_tag(elem): global testsuite level1, level2, level3, elem4, elem5, elem6 = elem # -- testsuite (level1) testsuite_level1 = ET.SubElement(testsuite, "testsuite") testsuite_level1.set("name", level1) # -- testsuite (level2) testsuite_level2 = ET.SubElement(testsuite_level1, "testsuite") testsuite_level2.set("name", level2) # -- testsuite (level3) testsuite_level2 = ET.SubElement(testsuite_level2, "testsuite") testsuite_level2.set("name", level3) # -- testcase testcase = ET.SubElement(testsuite_level2, "testcase") testcase.set("name", "TBD") summary = ET.SubElement(testcase, "summary") summary.text = "Test Type= %s, Automated= %s, Available=%s" %(elem4, elem5, elem6) with open(input_file) as in_file: for line_number, a_line in enumerate(in_file): try: parameters = a_line.split(';') if len(parameters) >= 6: level1 = parameters[0].strip() level2 = parameters[1].strip() level3 = parameters[2].strip() elem4 = parameters[3].strip() elem5 = parameters[4].strip() elem6 = parameters[5].strip() lines_as_list.append((level1, level2, level3, elem4, elem5, elem6)) except ValueError: pass lines_as_list.sort() for elem in lines_as_list: _create_testcase_tag(elem) output_xml = ET.ElementTree(testsuite) ET.ElementTree.write(output_xml, output_file, xml_declaration=True, encoding="UTF-8") The above code generates an XML like this: <testsuite name="Tests"> <testsuite name="Nav"> <testsuite name="Basic navigation"> <testsuite name="Set destination"> <testcase name="TBD"> <summary>Test Type= Smoke test Automated= No, Available=Yes</summary> </testcase> </testsuite> </testsuite> </testsuite> <testsuite name="Nav"> <testsuite name="Set destination"> <testsuite name="Recent"> <testcase name="TBD"> <summary> Test Type= Reggression test Automated= No, Available=Yes </summary> </testcase> </testsuite> </testsuite> </testsuite> </testsuite> ... This is all correct, but as you can see I have created a whole tree for each line and that is not what I need. I need to combine e.g. all testsuite with the same name into one testsuite and also perform that recursively. So the XML looks like this instead: <testsuite name="Tests"> <testsuite name="Nav"> <testsuite name="Basic navigation"> <testsuite name="Set destination"> <testcase name="TBD"> <summary>Test Type= Smoke test Automated= No, Available=Yes</summary> </testcase> </testsuite> <testsuite name="Recent"> <testcase name="TBD"> <summary> Test Type= Reggression test Automated= No, Available=Yes </summary> </testcase> </testsuite> </testsuite> </testsuite> </testsuite> I hope you can understand what I mean, but level1, level2 and level3 should be unique with testcases inside. How should I do this? Please do not suggest the use of any external libraries! I can not install new libraries in customer site. xml.etree.ElementTree is all I have. Thanks

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  • How should I model the database for this problem? And which ORM can handle it?

    - by Kristof Claes
    I need to build some sort of a custom CMS for a client of ours. These are some of the functional requirements: Must be able to manage the list of Pages in the site Each Page can contain a number of ColumnGroups A ColumnGroup is nothing more than a list of Columns in a certain ColumnGroupLayout. For example: "one column taking up the entire width of the page", "two columns each taking up half of the width", ... Each Column can contain a number ContentBlocks Examples of a ContentBlock are: TextBlock, NewsBlock, PictureBlock, ... ContentBlocks can be given a certain sorting within a Column A ContentBlock can be put in different Columns so that content can be reused without having to be duplicated. My first quick draft of how this could look like in C# code (we're using ASP.NET 4.0 to develop the CMS) can be found at the bottom of my question. One of the technical requirements is that it must be as easy as possible to add new types of ContentBlocks to the CMS. So I would like model everything as flexible as possible. Unfortunately, I'm already stuck at trying to figure out how the database should look like. One of the problems I'm having has to do with sorting different types of ContentBlocks in a Column. I guess each type of ContentBlock (like TextBlock, NewsBlock, PictureBlock, ...) should have it's own table in the database because each has it's own different fields. A TextBlock might only have a field called Text whereas a NewsBlock might have fields for the Text, the Summary, the PublicationDate, ... Since one Column can have ContentBlocks located in different tables, I guess I'll have to create a many-to-many association for each type of ContentBlock. For example: ColumnTextBlocks, ColumnNewsBlocks and ColumnPictureBlocks. The problem I have with this setup is the sorting of the different ContentBlocks in a column. This could be something like this: TextBlock NewsBlock TextBlock TextBlock PictureBlock Where do I store the sorting number? If I store them in the associaton tables, I'll have to update a lot of tables when changing the sorting order of ContentBlocks in a Column. Is this a good approach to the problem? Basically, my question is: What is the best way to model this keeping in mind that it should be easy to add new types of ContentBlocks? My next question is: What ORM can deal with that kind of modeling? To be honest, we are ORM-virgins at work. I have been reading a bit about Linq-to-SQL and NHibernate, but we have no experience with them. Because of the IList in the Column class (see code below) I think we can rule out Linq-to-SQL, right? Can NHibernate handle the mapping of data from many different tables to one IList? Also keep in mind that this is just a very small portion of the domain. Other parts are Users belonging to a certain UserGroup having certain Permissions on Pages, ColumnGroups, Columns and ContentBlocks. The code (just a quick first draft): public class Page { public int PageID { get; set; } public string Title { get; set; } public string Description { get; set; } public string Keywords { get; set; } public IList<ColumnGroup> ColumnGroups { get; set; } } public class ColumnGroup { public enum ColumnGroupLayout { OneColumn, HalfHalf, NarrowWide, WideNarrow } public int ColumnGroupID { get; set; } public ColumnGroupLayout Layout { get; set; } public IList<Column> Columns { get; set; } } public class Column { public int ColumnID { get; set; } public IList<IContentBlock> ContentBlocks { get; set; } } public interface IContentBlock { string GetSummary(); } public class TextBlock : IContentBlock { public string GetSummary() { return "I am a piece of text."; } } public class NewsBlock : IContentBlock { public string GetSummary() { return "I am a news item."; } }

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  • Reverse engineering windows mobile live search CellID location awareness protocol (yikes)...

    - by Jean-Charles
    I wasn't sure of how to form the question so I apologize if the title is misleading. Additionally, you may want to get some coffee and take a seat for this one ... It's long. Basically, I'm trying to reverse engineer the protocol used by the Windows Mobile Live Search application to get location based on cellID. Before I go on, I am aware of other open source services (such as OpenCellID) but this is more for the sake of education and a bit for redundancy. According to the packets I captured, a POST request is made to ... mobile.search.live.com/positionlookupservice_1/service.aspx ... with a few specific headers (agent, content-length, etc) and no body. Once this goes through, the server sends back a 100-Continue response. At this point, the application submits this data (I chopped off the packet header): 00 00 00 01 00 00 00 05 55 54 ........UT 46 2d 38 05 65 6e 2d 55 53 05 65 6e 2d 55 53 01 F-8.en-US.en-US. 06 44 65 76 69 63 65 05 64 75 6d 6d 79 01 06 02 .Device.dummy... 50 4c 08 0e 52 65 76 65 72 73 65 47 65 6f 63 6f PL..ReverseGeoco 64 65 01 07 0b 47 50 53 43 68 69 70 49 6e 66 6f de...GPSChipInfo 01 20 06 09 43 65 6c 6c 54 6f 77 65 72 06 03 43 . ..CellTower..C 47 49 08 03 4d 43 43 b6 02 07 03 4d 4e 43 03 34 GI..MCC....MNC.4 31 30 08 03 4c 41 43 cf 36 08 02 43 49 fd 01 00 10..LAC.6..CI... 00 00 00 ... And receives this in response (packet and HTTP response headers chopped): 00 00 00 01 00 00 00 00 01 06 02 50 4c ...........PL 06 08 4c 6f 63 61 6c 69 74 79 06 08 4c 6f 63 61 ..Locality..Loca 74 69 6f 6e 07 03 4c 61 74 09 34 32 2e 33 37 35 tion..Lat.42.375 36 32 31 07 04 4c 6f 6e 67 0a 2d 37 31 2e 31 35 621..Long.-71.15 38 39 33 38 00 07 06 52 61 64 69 75 73 09 32 30 8938...Radius.20 30 30 2e 30 30 30 30 00 42 07 0c 4c 6f 63 61 6c 00.0000.B..Local 69 74 79 4e 61 6d 65 09 57 61 74 65 72 74 6f 77 ityName.Watertow 6e 07 16 41 64 6d 69 6e 69 73 74 72 61 74 69 76 n..Administrativ 65 41 72 65 61 4e 61 6d 65 0d 4d 61 73 73 61 63 eAreaName.Massac 68 75 73 65 74 74 73 07 10 50 6f 73 74 61 6c 43 husetts..PostalC 6f 64 65 4e 75 6d 62 65 72 05 30 32 34 37 32 07 odeNumber.02472. 0b 43 6f 75 6e 74 72 79 4e 61 6d 65 0d 55 6e 69 .CountryName.Uni 74 65 64 20 53 74 61 74 65 73 00 00 00 ted States... Now, here is what I've determined so far: All strings are prepended with one byte that is the decimal equivalent of their length. There seem to be three different casts that are used throughout the request and response. They show up as one byte before the length byte. I've concluded that the three types map out as follows: 0x06 - parent element (subsequent values are children, closed with 0x00) 0x07 - string 0x08 - int? Based on these determinations, here is what the request and response look like in a more readable manner (values surrounded by brackets denote length and values surrounded by parenthesis denote a cast): \0x00\0x00\0x00\0x01\0x00\0x00\0x00 [5]UTF-8 [5]en-US [5]en-US \0x01 [6]Device [5]dummy \0x01 (6)[2]PL (8)[14]ReverseGeocode\0x01 (7)[11]GPSChipInfo[1]\0x20 (6)[9]CellTower (6)[3]CGI (8)[3]MCC\0xB6\0x02 //310 (7)[3]MNC[3]410 //410 (8)[3]LAC\0xCF\0x36 //6991 (8)[2]CI\0xFD\0x01 //259 \0x00 \0x00 \0x00 \0x00 and.. \0x00\0x00\0x00\0x01\0x00\0x00\0x00 \0x00\0x01 (6)[2]PL (6)[8]Locality (6)[8]Location (7)[3]Lat[9]42.375621 (7)[4]Long[10]-71.158938 \0x00 (7)[6]Radius[9]2000.0000 \0x00 \0x42 //"B" ... Has to do with GSM (7)[12]LocalityName[9]Watertown (7)[22]AdministrativeAreaName[13]Massachusetts (7)[16]PostalCodeNumber[5]02472 (7)[11]CountryName[13]United States \0x00 \0x00\0x00 My analysis seems to work out pretty well except for a few things: The 0x01s throughout confuse me ... At first I thought they were some sort of base level element terminators but I'm not certain. I'm not sure the 7-byte header is, in fact, a seven byte header. I wonder if it's maybe 4 bytes and that the three remaining 0x00s are of some other significance. The trailing 0x00s. Why is it that there is only one on the request but two on the response? The type 8 cast mentioned above ... I can't seem to figure out how those values are being encoded. I added comments to those lines with what the values should correspond to. Any advice on these four points will be greatly appreciated. And yes, these packets were captured in Watertown, MA. :)

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  • What does Ruby have that Python doesn't, and vice versa?

    - by Lennart Regebro
    There is a lot of discussions of Python vs Ruby, and I all find them completely unhelpful, because they all turn around why feature X sucks in language Y, or that claim language Y doesn't have X, although in fact it does. I also know exactly why I prefer Python, but that's also subjective, and wouldn't help anybody choosing, as they might not have the same tastes in development as I do. It would therefore be interesting to list the differences, objectively. So no "Python's lambdas sucks". Instead explain what Ruby's lambdas can do that Python's can't. No subjectivity. Example code is good! Don't have several differences in one answer, please. And vote up the ones you know are correct, and down those you know are incorrect (or are subjective). Also, differences in syntax is not interesting. We know Python does with indentation what Ruby does with brackets and ends, and that @ is called self in Python. UPDATE: This is now a community wiki, so we can add the big differences here. Ruby has a class reference in the class body In Ruby you have a reference to the class (self) already in the class body. In Python you don't have a reference to the class until after the class construction is finished. An example: class Kaka puts self end self in this case is the class, and this code would print out "Kaka". There is no way to print out the class name or in other ways access the class from the class definition body in Python. All classes are mutable in Ruby This lets you develop extensions to core classes. Here's an example of a rails extension: class String def starts_with?(other) head = self[0, other.length] head == other end end Ruby has Perl-like scripting features Ruby has first class regexps, $-variables, the awk/perl line by line input loop and other features that make it more suited to writing small shell scripts that munge text files or act as glue code for other programs. Ruby has first class continuations Thanks to the callcc statement. In Python you can create continuations by various techniques, but there is no support built in to the language. Ruby has blocks With the "do" statement you can create a multi-line anonymous function in Ruby, which will be passed in as an argument into the method in front of do, and called from there. In Python you would instead do this either by passing a method or with generators. Ruby: amethod { |here| many=lines+of+code goes(here) } Python: def function(here): many=lines+of+code goes(here) amethod(function) Interestingly, the convenience statement in Ruby for calling a block is called "yield", which in Python will create a generator. Ruby: def themethod yield 5 end themethod do |foo| puts foo end Python: def themethod(): yield 5 for foo in themethod: print foo Although the principles are different, the result is strikingly similar. Python has built-in generators (which are used like Ruby blocks, as noted above) Python has support for generators in the language. In Ruby you could use the generator module that uses continuations to create a generator from a block. Or, you could just use a block/proc/lambda! Moreover, in Ruby 1.9 Fibers are, and can be used as, generators. docs.python.org has this generator example: def reverse(data): for index in range(len(data)-1, -1, -1): yield data[index] Contrast this with the above block examples. Python has flexible name space handling In Ruby, when you import a file with require, all the things defined in that file will end up in your global namespace. This causes namespace pollution. The solution to that is Rubys modules. But if you create a namespace with a module, then you have to use that namespace to access the contained classes. In Python, the file is a module, and you can import its contained names with from themodule import *, thereby polluting the namespace if you want. But you can also import just selected names with from themodule import aname, another or you can simply import themodule and then access the names with themodule.aname. If you want more levels in your namespace you can have packages, which are directories with modules and an __init__.py file. Python has docstrings Docstrings are strings that are attached to modules, functions and methods and can be introspected at runtime. This helps for creating such things as the help command and automatic documentation. def frobnicate(bar): """frobnicate takes a bar and frobnicates it >>> bar = Bar() >>> bar.is_frobnicated() False >>> frobnicate(bar) >>> bar.is_frobnicated() True """ Python has more libraries Python has a vast amount of available modules and bindings for libraries. Python has multiple inheritance Ruby does not ("on purpose" -- see Ruby's website, see here how it's done in Ruby). It does reuse the module concept as a sort of abstract classes. Python has list/dict comprehensions Python: res = [x*x for x in range(1, 10)] Ruby: res = (0..9).map { |x| x * x } Python: >>> (x*x for x in range(10)) <generator object <genexpr> at 0xb7c1ccd4> >>> list(_) [0, 1, 4, 9, 16, 25, 36, 49, 64, 81] Ruby: p = proc { |x| x * x } (0..9).map(&p) Python: >>> {x:str(y*y) for x,y in {1:2, 3:4}.items()} {1: '4', 3: '16'} Ruby: >> Hash[{1=>2, 3=>4}.map{|x,y| [x,(y*y).to_s]}] => {1=>"4", 3=>"16"} Python has decorators Things similar to decorators can be created in Ruby, and it can also be argued that they aren't as necessary as in Python.

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  • What statistics can be maintained for a set of numerical data without iterating?

    - by Dan Tao
    Update Just for future reference, I'm going to list all of the statistics that I'm aware of that can be maintained in a rolling collection, recalculated as an O(1) operation on every addition/removal (this is really how I should've worded the question from the beginning): Obvious Count Sum Mean Max* Min* Median** Less Obvious Variance Standard Deviation Skewness Kurtosis Mode*** Weighted Average Weighted Moving Average**** OK, so to put it more accurately: these are not "all" of the statistics I'm aware of. They're just the ones that I can remember off the top of my head right now. *Can be recalculated in O(1) for additions only, or for additions and removals if the collection is sorted (but in this case, insertion is not O(1)). Removals potentially incur an O(n) recalculation for non-sorted collections. **Recalculated in O(1) for a sorted, indexed collection only. ***Requires a fairly complex data structure to recalculate in O(1). ****This can certainly be achieved in O(1) for additions and removals when the weights are assigned in a linearly descending fashion. In other scenarios, I'm not sure. Original Question Say I maintain a collection of numerical data -- let's say, just a bunch of numbers. For this data, there are loads of calculated values that might be of interest; one example would be the sum. To get the sum of all this data, I could... Option 1: Iterate through the collection, adding all the values: double sum = 0.0; for (int i = 0; i < values.Count; i++) sum += values[i]; Option 2: Maintain the sum, eliminating the need to ever iterate over the collection just to find the sum: void Add(double value) { values.Add(value); sum += value; } void Remove(double value) { values.Remove(value); sum -= value; } EDIT: To put this question in more relatable terms, let's compare the two options above to a (sort of) real-world situation: Suppose I start listing numbers out loud and ask you to keep them in your head. I start by saying, "11, 16, 13, 12." If you've just been remembering the numbers themselves and nothing more, and then I say, "What's the sum?", you'd have to think to yourself, "OK, what's 11 + 16 + 13 + 12?" before responding, "52." If, on the other hand, you had been keeping track of the sum yourself while I was listing the numbers (i.e., when I said, "11" you thought "11", when I said "16", you thought, "27," and so on), you could answer "52" right away. Then if I say, "OK, now forget the number 16," if you've been keeping track of the sum inside your head you can simply take 16 away from 52 and know that the new sum is 36, rather than taking 16 off the list and them summing up 11 + 13 + 12. So my question is, what other calculations, other than the obvious ones like sum and average, are like this? SECOND EDIT: As an arbitrary example of a statistic that (I'm almost certain) does require iteration -- and therefore cannot be maintained as simply as a sum or average -- consider if I asked you, "how many numbers in this collection are divisible by the min?" Let's say the numbers are 5, 15, 19, 20, 21, 25, and 30. The min of this set is 5, which divides into 5, 15, 20, 25, and 30 (but not 19 or 21), so the answer is 5. Now if I remove 5 from the collection and ask the same question, the answer is now 2, since only 15 and 30 are divisible by the new min of 15; but, as far as I can tell, you cannot know this without going through the collection again. So I think this gets to the heart of my question: if we can divide kinds of statistics into these categories, those that are maintainable (my own term, maybe there's a more official one somewhere) versus those that require iteration to compute any time a collection is changed, what are all the maintainable ones? What I am asking about is not strictly the same as an online algorithm (though I sincerely thank those of you who introduced me to that concept). An online algorithm can begin its work without having even seen all of the input data; the maintainable statistics I am seeking will certainly have seen all the data, they just don't need to reiterate through it over and over again whenever it changes.

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  • Copying one form's values to another form using JQuery

    - by rsturim
    I have a "shipping" form that I want to offer users the ability to copy their input values over to their "billing" form by simply checking a checkbox. I've coded up a solution that works -- but, I'm sort of new to jQuery and wanted some criticism on how I went about achieving this. Is this well done -- any refactorings you'd recommend? Any advice would be much appreciated! The Script <script type="text/javascript"> $(function() { $("#copy").click(function() { if($(this).is(":checked")){ var $allShippingInputs = $(":input:not(input[type=submit])", "form#shipping"); $allShippingInputs.each(function() { var billingInput = "#" + this.name.replace("ship", "bill"); $(billingInput).val($(this).val()); }) //console.log("checked"); } else { $(':input','#billing') .not(':button, :submit, :reset, :hidden') .val('') .removeAttr('checked') .removeAttr('selected'); //console.log("not checked") } }); }); </script> The Form <div> <form action="" method="get" name="shipping" id="shipping"> <fieldset> <legend>Shipping</legend> <ul> <li> <label for="ship_first_name">First Name:</label> <input type="text" name="ship_first_name" id="ship_first_name" value="John" size="" /> </li> <li> <label for="ship_last_name">Last Name:</label> <input type="text" name="ship_last_name" id="ship_last_name" value="Smith" size="" /> </li> <li> <label for="ship_state">State:</label> <select name="ship_state" id="ship_state"> <option value="RI">Rhode Island</option> <option value="VT" selected="selected">Vermont</option> <option value="CT">Connecticut</option> </select> </li> <li> <label for="ship_zip_code">Zip Code</label> <input type="text" name="ship_zip_code" id="ship_zip_code" value="05401" size="8" /> </li> <li> <input type="submit" name="" /> </li> </ul> </fieldset> </form> </div> <div> <form action="" method="get" name="billing" id="billing"> <fieldset> <legend>Billing</legend> <ul> <li> <input type="checkbox" name="copy" id="copy" /> <label for="copy">Same of my shipping</label> </li> <li> <label for="bill_first_name">First Name:</label> <input type="text" name="bill_first_name" id="bill_first_name" value="" size="" /> </li> <li> <label for="bill_last_name">Last Name:</label> <input type="text" name="bill_last_name" id="bill_last_name" value="" size="" /> </li> <li> <label for="bill_state">State:</label> <select name="bill_state" id="bill_state"> <option>-- Choose State --</option> <option value="RI">Rhode Island</option> <option value="VT">Vermont</option> <option value="CT">Connecticut</option> </select> </li> <li> <label for="bill_zip_code">Zip Code</label> <input type="text" name="bill_zip_code" id="bill_zip_code" value="" size="8" /> </li> <li> <input type="submit" name="" /> </li> </ul> </fieldset> </form> </div>

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  • How to associate Wi-Fi beacon info with a virtual "location"?

    - by leander
    We have a piece of embedded hardware that will sense 802.11 beacons, and we're using this to make a map of currently visible bssid -> signalStrength. Given this map, we would like to make a determination: Is this likely to be a location I have been to before? If so, what is its ID? If not, I should remember this location: generate a new ID. Now what should I store (and how should I store it) to make future determinations easier? This is for an augmented-reality app/game. We will be using it to associate particular characters and events with "locations". The device does not have internet or cellular access, so using a geolocation service is out of consideration for the time being. (We don't really need to know where we are in reality, just be able to determine if we return there.) It isn't crucial that it be extremely accurate, but it would be nice if it was tolerant to signal strength changes or the occasional missing beacon. It should be usable in relatively low numbers of access points (e.g. rural house with one wireless router) or many (wandering around a dense metropolis). In the case of a city, it should change location every few minutes of walking (continuously-overlapping signals make this a bit more tricky in naive code). A reasonable number of false positives (match a location when we aren't actually there) is acceptable. The wrong character/event showing up just adds a bit of variety. False negatives (no location match) are a bit more troublesome: this will tend to add a better-matching new location to the saved locations, masking the old one. While we will have additional logic to ensure locations that the device hasn't seen in a while will "orphan" any associated characters or events (if e.g. you move to a different country), we'd prefer not to mask and eventually orphan locations you do visit regularly. Some technical complications: signalStrength is returned as 1-4; presumably it's related to dB, but we are not sure exactly how; in my experiments it tends to stick to either 1 or 4, but occasionally we see numbers in between. (Tech docs on the hardware are sparse.) The device completes a scan of one-quarter of the channel space every second; so it takes about 4-5 seconds to get a complete picture of what's around. The list isn't always complete. (We are making strides to fix this using some slight sampling period randomization, as recommended by the library docs. We're also investigating ways to increase the number of scans without killing our performance; the hardware/libs are poorly behaved when it comes to saturating the bus.) We have only kilobytes to store our history. We have a "working" impl now, but it is relatively naive, and flaky in the face of real-world Wi-Fi behavior. Rough pseudocode: // recordLocation() -- only store strength 4 locations m_savedLocations[g_nextId++] = filterForStrengthGE( m_currentAPs, 4 ); // determineLocation() bestPoints = -inf; foreach ( oldLoc in m_savedLocations ) { points = 0.0; foreach ( ap in m_currentAPs ) { if ( oldLoc.has( ap ) ) { switch ( ap.signalStrength ) { case 3: points += 1.0; break; case 4: points += 2.0; break; } } } points /= oldLoc.numAPs; if ( points > bestPoints ) { bestLoc = oldLoc; bestPoints = points; } } if ( bestLoc && bestPoints > 1.0 ) { if ( bestPoints >= (2.0 - epsilon) ) { // near-perfect match. // update location with any new high-strength APs that have appeared bestLoc.addAPs( filterForStrengthGE( m_currentAPs, 4 ) ); } return bestLoc; } else { return NO_MATCH; } We record a location currently only when we have NO_MATCH and the app determines it's time for a new event. (The "near-perfect match" code above would appear to make it harder to match in the future... It's mostly to keep new powerful APs from being associated with other locations, but you'd think we'd need something to counter this if e.g. an AP doesn't show up in the next 10 times I match a location.) I have a feeling that we're missing some things from set theory or graph theory that would assist in grouping/classification of this data, and perhaps providing a better "confidence level" on matches, and better robustness against missed beacons, signal strength changes, and the like. Also it would be useful to have a good method for mutating locations over time. Any useful resources out there for this sort of thing? Simple and/or robust approaches we're missing?

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  • Monotouch UITableView image "flashing" while background requests are fetched

    - by Themos Piperakis
    I am in need of some help from you guys. I have a Monotouch UITableView which contains some web images. I have implemented a Task to fetch them asynchronously so the UI is responsive, an even added some animations to fade them in when they are fetched from the web. My problems start when the user scrolls down very fast down the UITableView, so since the cells are resusable, several background tasks are queued for images. When he is at the bottom of the list, he might see the thumbnail displaying an image for another cell, then another, then another, then another, as the tasks are completed and each image replaces the other one. I am in need of some sort of checking whether the currently displayed cell corresponds to the correct image url, but not sure how to do that. Here is the code for my TableSource class. using System; using MonoTouch.UIKit; using MonoTouch.Foundation; using System.Collections.Generic; using System.Threading; using System.Threading.Tasks; using System.Diagnostics; { public class ListDelegate:UITableViewDelegate { private UINavigationController nav; public override float GetHeightForRow (UITableView tableView, NSIndexPath indexPath) { return 128; } public override void RowSelected (UITableView tableView, NSIndexPath indexPath) { DealViewController c = new DealViewController(((ListDataSource)tableView.DataSource).deals[indexPath.Row].Id,nav); nav.PushViewController(c,true); tableView.DeselectRow(indexPath,true); } public ListDelegate(UINavigationController nav) { this.nav = nav; } } public class ListDataSource:UITableViewDataSource { bool toggle=true; Dictionary<string,UIImage> images = new Dictionary<string, UIImage>(); public List<MyDeal> deals = new List<MyDeal>(); Dictionary<int,ListCellViewController> controllers = new Dictionary<int, ListCellViewController>(); public ListDataSource(List<MyDeal> deals) { this.deals = deals; } public override int RowsInSection (UITableView tableview, int section) { return deals.Count; } public override UITableViewCell GetCell (UITableView tableView, MonoTouch.Foundation.NSIndexPath indexPath) { UITableViewCell cell = tableView.DequeueReusableCell("cell"); ListCellViewController cellController = null; if (cell == null || !controllers.ContainsKey(cell.Tag)) { cellController = new ListCellViewController(); NSBundle.MainBundle.LoadNib("ListCellViewController", cellController, null); cell = cellController.Cell; cell.Tag = Environment.TickCount; controllers.Add(cell.Tag, cellController); } else { cellController = controllers[cell.Tag]; } if (toggle) { cell.BackgroundView = new UIImageView(UIImage.FromFile("images/bg1.jpg")); } else { cell.BackgroundView = new UIImageView(UIImage.FromFile("images/bg2.jpg")); } toggle = !toggle; MyDeal d = deals[indexPath.Row]; cellController.SetValues(d.Title,d.Price,d.Value,d.DiscountPercent); GetImage(cellController.Thumbnail,d.Thumbnail); return cell; } private void GetImage(UIImageView img, string url) { img.Alpha = 0; if (url != string.Empty) { if (images.ContainsKey(url)) { img.Image = images[url]; img.Alpha = 1; } else { var context = TaskScheduler.FromCurrentSynchronizationContext (); Task.Factory.StartNew (() => { NSData imageData = NSData.FromUrl(new NSUrl(url)); var uimg = UIImage.LoadFromData(imageData); images.Add(url,uimg); return uimg; }).ContinueWith (t => { InvokeOnMainThread(()=>{ img.Image = t.Result; RefreshImage(img); }); }, context); } } } private void RefreshImage(UIImageView img) { UIView.BeginAnimations("imageThumbnailTransitionIn"); UIView.SetAnimationDuration(0.5f); img.Alpha = 1.0f; UIView.CommitAnimations(); } } } Here is the ListCellViewController, that contains a custom cell using System; using System.Collections.Generic; using System.Linq; using MonoTouch.Foundation; using MonoTouch.UIKit; { public partial class ListCellViewController : UIViewController { #region Constructors // The IntPtr and initWithCoder constructors are required for items that need // to be able to be created from a xib rather than from managed code public ListCellViewController (IntPtr handle) : base(handle) { Initialize (); } [Export("initWithCoder:")] public ListCellViewController (NSCoder coder) : base(coder) { Initialize (); } public ListCellViewController () : base("ListCellViewController", null) { Initialize (); } void Initialize () { } public UIImageView Thumbnail { get{return thumbnailView;} } public UITableViewCell Cell { get {return cell;} } public void SetValues(string title,decimal price,decimal valuex,decimal discount,int purchases) { } #endregion } } All help is greatly appreciated

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  • Anyone succeeded at injecting Interfaces into Entity Framework 4 Entities, using T4?

    - by Ciel
    Hello: POCO sort of leaves me wanting: (how can I say I use DI/IoC, if the Repository is not the only place that is creating the entities?)...hence my desire to lock it down, get rid of the temptation of newing up POCOs or EntityObjects anywhere in the code, and just allowing entity interfaces above the Repository/Factory layer. For a second there, I nearly thought I had it...was editing EF4's T4 in order to inject in an Interface def. Was going swimmingly, compiled and worked, until I got to the Associations... I wrapped them with a ICollection, and renamed the underlying original collection with a prefix of Wrapped. Unfortunately, when run, throws an error: //The Member 'WrappedSubExamples' in the CLR type 'XAct.App.Data.Model.EF4.Example' is not present in the conceptual model type 'XAct.App.Data.Model.Entity.Example'. var examples = context2.CreateObjectSet(); My T4 segment I used was (this may not work, as it's the longest code snippet I've ever posted here...sorry): #region Generic Property Abstraction <# if (navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many) {#> //XAct.App Generic Wrapper: <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> ICollection<I<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> <#=code.Escape(navProperty)#> { get { if (_X<#=code.Escape(navProperty)# == null){ _X<#=code.Escape(navProperty)# = new WrappedCollection,<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#(this.<#=(navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many)?"Wrapped":""#<#=code.Escape(navProperty)#); } return _X<#=code.Escape(navProperty)#; } } private ICollection _X<#=code.Escape(navProperty)#; <# } else { # <#=code.SpaceAfter(NewModifier(navProperty))#<#=Accessibility.ForProperty(navProperty)# I<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)# <#=code.Escape(navProperty)# { get { return (I<#=code.Escape(navProperty)#)this.Wrapped<#=code.Escape(navProperty)#; } set { this.Wrapped<#=code.Escape(navProperty)# = value as <#=code.Escape(navProperty)#; } } <# } # #endregion which then wraps the original collection, renamed with the prefix 'Wrapped': /// <summary> /// <#=SummaryComment(navProperty)#> /// </summary><#=LongDescriptionCommentElement(navProperty, region.CurrentIndentLevel) #> [XmlIgnoreAttribute()] [SoapIgnoreAttribute()] [DataMemberAttribute()] [EdmRelationshipNavigationPropertyAttribute("<#=navProperty.RelationshipType.NamespaceName#>", "<#=navProperty.RelationshipType.Name#>", "<#=navProperty.ToEndMember.Name#>")] <# if (navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many) { #> <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> EntityCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> Wrapped<#=code.Escape(navProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>"); } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { if ((value != null)) { ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>", value); } } } <# } else { #> <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> <#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#> Wrapped<#=code.Escape(navProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>").Value; } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>").Value = value; } } <# string refPropertyName = navProperty.Name + "Reference"; if (entity.Members.Any(m => m.Name == refPropertyName)) { // 6017 is the same error number that EntityClassGenerator uses. Errors.Add(new System.CodeDom.Compiler.CompilerError(SourceCsdlPath, -1, -1, "6017", String.Format(CultureInfo.CurrentCulture, GetResourceString("Template_ConflictingGeneratedNavPropName"), navProperty.Name, entity.FullName, refPropertyName))); } #> /// <summary> /// <#=SummaryComment(navProperty)#> /// </summary><#=LongDescriptionCommentElement(navProperty, region.CurrentIndentLevel)#> [BrowsableAttribute(false)] [DataMemberAttribute()] <#=Accessibility.ForProperty(navProperty)#> EntityReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> <#=refPropertyName#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>"); } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { if ((value != null)) { ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>", value); } } } <# } The point is...it bugs out. I've tried various solutions...none worked. Any ideas -- or is this just a wild goose chase, and time to give it up?

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  • How should I change my Graph structure (very slow insertion)?

    - by Nazgulled
    Hi, This program I'm doing is about a social network, which means there are users and their profiles. The profiles structure is UserProfile. Now, there are various possible Graph implementations and I don't think I'm using the best one. I have a Graph structure and inside, there's a pointer to a linked list of type Vertex. Each Vertex element has a value, a pointer to the next Vertex and a pointer to a linked list of type Edge. Each Edge element has a value (so I can define weights and whatever it's needed), a pointer to the next Edge and a pointer to the Vertex owner. I have a 2 sample files with data to process (in CSV style) and insert into the Graph. The first one is the user data (one user per line); the second one is the user relations (for the graph). The first file is quickly inserted into the graph cause I always insert at the head and there's like ~18000 users. The second file takes ages but I still insert the edges at the head. The file has about ~520000 lines of user relations and takes between 13-15mins to insert into the Graph. I made a quick test and reading the data is pretty quickly, instantaneously really. The problem is in the insertion. This problem exists because I have a Graph implemented with linked lists for the vertices. Every time I need to insert a relation, I need to lookup for 2 vertices, so I can link them together. This is the problem... Doing this for ~520000 relations, takes a while. How should I solve this? Solution 1) Some people recommended me to implement the Graph (the vertices part) as an array instead of a linked list. This way I have direct access to every vertex and the insertion is probably going to drop considerably. But, I don't like the idea of allocating an array with [18000] elements. How practically is this? My sample data has ~18000, but what if I need much less or much more? The linked list approach has that flexibility, I can have whatever size I want as long as there's memory for it. But the array doesn't, how am I going to handle such situation? What are your suggestions? Using linked lists is good for space complexity but bad for time complexity. And using an array is good for time complexity but bad for space complexity. Any thoughts about this solution? Solution 2) This project also demands that I have some sort of data structures that allows quick lookup based on a name index and an ID index. For this I decided to use Hash Tables. My tables are implemented with separate chaining as collision resolution and when a load factor of 0.70 is reach, I normally recreate the table. I base the next table size on this http://planetmath.org/encyclopedia/GoodHashTablePrimes.html. Currently, both Hash Tables hold a pointer to the UserProfile instead of duplication the user profile itself. That would be stupid, changing data would require 3 changes and it's really dumb to do it that way. So I just save the pointer to the UserProfile. The same user profile pointer is also saved as value in each Graph Vertex. So, I have 3 data structures, one Graph and two Hash Tables and every single one of them point to the same exact UserProfile. The Graph structure will serve the purpose of finding the shortest path and stuff like that while the Hash Tables serve as quick index by name and ID. What I'm thinking to solve my Graph problem is to, instead of having the Hash Tables value point to the UserProfile, I point it to the corresponding Vertex. It's still a pointer, no more and no less space is used, I just change what I point to. Like this, I can easily and quickly lookup for each Vertex I need and link them together. This will insert the ~520000 relations pretty quickly. I thought of this solution because I already have the Hash Tables and I need to have them, then, why not take advantage of them for indexing the Graph vertices instead of the user profile? It's basically the same thing, I can still access the UserProfile pretty quickly, just go to the Vertex and then to the UserProfile. But, do you see any cons on this second solution against the first one? Or only pros that overpower the pros and cons on the first solution? Other Solution) If you have any other solution, I'm all ears. But please explain the pros and cons of that solution over the previous 2. I really don't have much time to be wasting with this right now, I need to move on with this project, so, if I'm doing to do such a change, I need to understand exactly what to change and if that's really the way to go. Hopefully no one fell asleep reading this and closed the browser, sorry for the big testament. But I really need to decide what to do about this and I really need to make a change. P.S: When answering my proposed solutions, please enumerate them as I did so I know exactly what are you talking about and don't confuse my self more than I already am.

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  • A new method of supporting FOSS?

    - by James
    I have been kicking an idea around for sometime and wondered if something of it's nature hadn't already been invented. The premise is a website that integrates code management, project/team management, and micro-transactions. Donations, in and of themselves, are a sporadic, and unreliable method of supporting developers. Furthermore most free software that accepts donations is started by programmers ,be it to learn, because of a hobby, or because they saw a niche that needed to be filled. There is no method in place of of saying "hay, the FOSS community needs this kind of software, will someone develop it, and accept donations!?" Programmers should be programming, not busy begging for money. Basically the idea is people can go to the site in question, and start a project or make a request. Anyone signed up with the site can start a request. Each member account is free to support or "upvote" a project request. Requests and the associated number of votes let programmers in the community know the needs of the community. When a project is started a request for developers can be put forth. Developers have a ranking based on commits to other projects. The project founder can send invites to known Developers, or accept invites from members based on developer ranking. Once the project has at least one team-member, an objectives sheet or "draft" can be put out, listing design, goals, and features. The founding member and each team-member may contribute to this sheet. Each "milestone", or "Feature" is represented by an article. An article is any unit of a draft that can be voted on by The Project Founder, Team-members, and contributors...which brings me to the next half of this idea. --Microtransactions-- People signed up with this hypothetical website can purchase credits which then can be transfered to projects they would like to support. Anyone who transfers credits to a project is known as a contributor to that project. At anytime a Founder, or the lead team-member may submit an article, or a design (multiple articles) for consideration. All team-members, as well as the Founder, can vote once for each article freely. Contributors may vote yes or no on a number of articles (independent of any given meeting where a particular design or article is considered) equal to the number of credits they have placed into a contributors fund for that particular project. A contributors fund is a proxy between a sites credit account, and a projects credit account. It is sort of like a promise to contribute, instead of an actual contribution. Contributers may place constraints on particular articles such that if those constraints (a yes or no vote) are satisfied then a manually specified amount of credits is automatically transfered to the project account. This allows a project to develop based on the needs of those who may (in the future) financially rely on the project. --- Code commits & milestones --- When a team-member makes a commit, they may specify if it's a minor commit, a bug fix, a compatibility patch (i.e. for a new platform), or a milestone (an article voted on previously). People signed up with the website, may download the updated project and test it to see if the programmer's assertion is true about the commit. A report may then be filed on a small form, giving a one or two paragraphs, and a positive or negative confirmation of the programmer's goal for that particular commit. After all milestones for a particular draft are complete, a new draft is submitted for voting. Also funds may withdrawn by each team-member based on the proportion of commits and milestones confirmed (fulfilled the stated purpose) for each programmer. --- voting --- Members, contributor, and non-contributor, may make priority requests for particular articles of a draft. The project founder may or may not opt to fill those requests based on the volume of upvotes. A fulfilled priority request means that any team-member that makes a community-confirmed commit for an article is, when all articles for the draft are fulfilled, granted a portion of project credits in proportion to the average priority of all the articles he committed. ---- Notes --- While this is horribly prone to design-by-committee the one saving grace is that the lead team-member may place constraints on a draft such that some, or ALL articles must be voted yes. Commits may not begin until a draft satisfying said constraints is approved. What does SO think, is this idea feasible? Does anyone see major problems with this? Is there any insights, or improvements that could be made?

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  • Arraylist is null; I cannot access books in the arraylist

    - by user3701380
    I am a beginner-intermediate java programmer and I am getting a null pointer exception from my arraylist. I am writing a bookstore program for APCS and when i add the book, it is supposed to add to the arraylist in the inventory class. But when i call a method to search for a book (e.g. by title), it shows that there isn't anything in the arraylist. //Here is my inventory class -- it has all methods for adding the book or searching for one The searching methods are in getBookByTitle, getBookByAuthor, and getBookByISBN and the method for adding a book is addBook package webbazonab; //Inventory Class //Bharath Senthil //Ansh Sikka import java.util.ArrayList; public class Inventory{ private ArrayList<Book> allBooks = new ArrayList<Book>(); private String bookTitles; private String bookAuthors; private String bookPrices; private String bookCopies; private String ISBNs; public Inventory() { } //@param double price, int copies, String bookTitle, String Author, String isbnNumber public void addBooks(Book addedBook){ allBooks.add(addedBook); } public boolean isAvailable(){ for(Book myBook : allBooks){ if(myBook.copiesLeft() == 0) return false; } return true; } public String populateTitle(){ for (Book titleBooks : allBooks){ bookTitles = titleBooks.getTitle() + "\n"; return bookTitles; } return bookTitles; } public String populateAuthor(){ for(Book authorBooks : allBooks){ bookAuthors = authorBooks.getAuthor() + "\n"; return bookAuthors; } return bookAuthors; } public String populatePrice(){ for (Book pricedBooks : allBooks){ bookPrices = String.valueOf(pricedBooks.getPrice()) + "\n"; } return "$" + bookPrices; } /** * * @return */ public String populateCopies(){ for (Book amtBooks : allBooks){ bookCopies = String.valueOf(amtBooks.copiesLeft()) + "\n"; return bookCopies; } return bookCopies; } public String populateISBN(){ for (Book isbnNums : allBooks){ ISBNs = isbnNums.getIsbn() + "\n"; return ISBNs; } return ISBNs; } @SuppressWarnings("empty-statement") public Book getBookByTitle(String titleSearch) { for(Book titleBook : allBooks) { if (titleBook.getTitle().equals(titleSearch)) { return titleBook; } } return null; } public Book getBookByISBN(String isbnSearch){ for(Book isbnBookSearches : allBooks){ if(isbnBookSearches.getIsbn().equals(isbnSearch)){ return isbnBookSearches; } } return null; } public Book getBookByAuthor(String authorSearch){ for(Book authorBookSearches : allBooks){ if(authorBookSearches.getAuthor().equals(authorSearch)){ return authorBookSearches; } } return null; } public void sort(){ for(int i = 0; i < allBooks.size(); i++) { for(int k = 0; k < allBooks.size(); k++) { if(((Book) allBooks.get(i)).getIsbn().compareTo(((Book) allBooks.get(k)).getIsbn()) < 1) { Book temp = (Book) allBooks.get(k); allBooks.set(k, allBooks.get(i)); allBooks.set(i, temp); } else if(((Book) allBooks.get(i)).getIsbn().compareTo(((Book) allBooks.get(k)).getIsbn()) > 1) { Book temp = (Book) allBooks.get(i); allBooks.set(i, allBooks.get(k)); allBooks.set(k, temp); } } } } public ArrayList<Book> getBooks(){ return allBooks; } } //The exception occurs when i call the method here (in another class): Inventory lib = new Inventory(); jTextField12.setText(lib.getBookByAuthor(authorSearch).getTitle()); Here is my book class if you need it package webbazonab; //Webbazon AB //Project By: Ansh Sikka and Bharath Senthil public class Book { private double myPrice; private String myTitle; private String bookAuthor; private String isbn; private int myCopies; public Book(double price, int copies, String bookTitle, String Author, String isbnNumber) { myPrice = price; myCopies = copies; myTitle = bookTitle; bookAuthor = Author; isbn = isbnNumber; } public double getPrice() { return myPrice; } public String getIsbn() { return isbn; } public String getTitle() { return myTitle; } public String getAuthor() { return bookAuthor; } public int copiesLeft(){ return myCopies; } public String notFound(){ return "The book you searched for could not be found!"; } public String toString() { return "Title: " + getTitle() + "\nAuthor: " + getAuthor() + "\nNumber of Available Books: " + copiesLeft() + "\nPrice: $" + getPrice(); } } Thanks!

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