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  • How to access string[] in xhtml page

    - by Kalpana
    I am having a simple string array in my bean as public String[] colors = new String[]{"red", "blue", "green"}; and trying to display these colors from my xhtml as but I am getting a java.lang.NumberFormatException: For input string: "colors" java.lang.NumberFormatException: For input string: "colors" at java.lang.NumberFormatException.forInputString(NumberFormatException. java:48) at java.lang.Integer.parseInt(Integer.java:447) at java.lang.Integer.parseInt(Integer.java:497) at javax.el.ListELResolver.coerce(ListELResolver.java:166) at javax.el.ListELResolver.getValue(ListELResolver.java:51) at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:54)

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  • Like query ing LINQ to Object

    - by Pankaj
    Hello All i have a US states list List<string> state // contain all 51 US states Now i have a string which contain some text like okl (it means Oklahoma for me). what i want i want 'like' query in List state and get Oklahoma state.

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  • Rails 3 Atom Feed

    - by scud bomb
    Trying to create an atom feed in Rails 3. When i refresh my browser i see basic XML, not the Atom feed im looking for. class PostsController < ApplicationController # GET /posts # GET /posts.xml def index @posts = Post.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @posts } format.atom end end index.atom.builder atom_feed do |feed| feed.title "twoconsortium feed" @posts.each do |post| feed.entry(post) do |entry| entry.title post.title entry.content post.text end end end localhost:3000/posts.atom looks like this: <?xml version="1.0" encoding="UTF-8"?> <feed xml:lang="en-US" xmlns="http://www.w3.org/2005/Atom"> <id>tag:localhost,2005:/posts</id> <link rel="alternate" type="text/html" href="http://localhost:3000"/> <link rel="self" type="application/atom+xml" href="http://localhost:3000/posts.atom"/> <title>my feed</title> <entry> <id>tag:localhost,2005:Post/1</id> <published>2012-03-27T18:26:13Z</published> <updated>2012-03-27T18:26:13Z</updated> <link rel="alternate" type="text/html" href="http://localhost:3000/posts/1"/> <title>First post</title> <content>good stuff</content> </entry> <entry> <id>tag:localhost,2005:Post/2</id> <published>2012-03-27T19:51:18Z</published> <updated>2012-03-27T19:51:18Z</updated> <link rel="alternate" type="text/html" href="http://localhost:3000/posts/2"/> <title>Second post</title> <content>its that second post type stuff</content> </entry> </feed>

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  • Deserialization error in a new environment

    - by cerhart
    I have a web application that calls a third-party web service. When I run it locally, I have no problems, but when I move it to my production environment, I get the following error: There is an error in XML document (2, 428). Stack: at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events) at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle) at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at RMXClasses.RMXContactService.ContactService.getActiveSessions(String user, String pass) in C:\Users\hp\Documents\Visual Studio 2008\Projects\ReklamStore\RMXClasses\Web References\RMXContactService\Reference.cs:line 257 at I have used the same web config file from the production environment but it still works locally. My local machine is a running vista home edition and the production environment is windows server 2003. The application is written in asp.net 3.5, wierdly under the asp.net config tab in iis, 3.5 doesn't show up in the drop down list, although that version of the framework is installed. The error is not being thrown in my code, it happens during serialization. I called the method on the proxy, I have checked the arguments and they are OK. I have also logged the SOAP request and response, and they both look OK as well. I am really at a loss here. Any ideas? SOAP log: This is the soap response that the program seems to have trouble parsing only on server 2003. On my machine the soap is identical, and yet it parses with no problems. SoapResponse BeforeDeserialize; <?xml version="1.0" encoding="UTF-8"?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="urn:ContactService" xmlns:ns2="http://api.yieldmanager.com/types" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><ns1:getActiveSessionsResponse> <sessions SOAP-ENC:arrayType="ns2:session[1]" xsi:type="ns2:array_of_session"> <item xsi:type="ns2:session"> <token xsi:type="xsd:string">xxxxxxxxxxxxxxxxxxxx1ae12517584b</token> <creation_time xsi:type="xsd:dateTime">2009-09-25T05:51:19Z</creation_time> <modification_time xsi:type="xsd:dateTime">2009-09-25T05:51:19Z</modification_time> <ip_address xsi:type="xsd:string">xxxxxxxxxx</ip_address> <contact_id xsi:type="xsd:long">xxxxxx</contact_id></item></sessions> </ns1:getActiveSessionsResponse></SOAP-ENV:Body></SOAP-ENV:Envelope>

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  • how to increase the limit of exceptions in oracle

    - by Arunachalam
    how to increase the limit of exceptions in oracle ? i have a excel sheet in which their are about 900 records to be appended .so i converted the excel to dat file and wrote a batch file that read from the dat file and appends it to the concern table but the batch file stop execution once the exceptions reach 51(all integrity constrain parent key not found) so the remaining valid files are not updated .its very difficult to find which record has integrity constrain is there a way to increase this exception limit ?

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  • no such file to load -- rails (MissingSourceFile)... say what?!!

    - by Julian
    Hello, I'm having an obnoxious and weird problem while trying to include the ThinkingTank gem into my rails project. When I include gem 'thinkingtank' in my project's Gemfile I get the following error: ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require': no such file to load -- rails (MissingSourceFile) from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:521:in `new_constants_in' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/activesupport-2.3.5/lib/active_support/dependencies.rb:156:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/thinkingtank-0.0.5/lib/thinkingtank.rb:1 from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `each' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `each' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in `require' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/bundler-1.0.7/lib/bundler.rb:112:in `require' from ~/git/myproject/config/boot.rb:121:in `load_environment' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:137:in `process' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:113:in `send' from ~/.rvm/gems/ree-1.8.7-2010.01/gems/rails-2.3.5/lib/initializer.rb:113:in `run' from ~/git/myproject/config/environment.rb:9 from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:254:in `require' from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:254:in `load_modules' from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:252:in `each' from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:252:in `load_modules' from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb/init.rb:21:in `setup' from ~/.rvm/rubies/ree-1.8.7-2010.01/lib/ruby/1.8/irb.rb:54:in `start' from ~/.rvm/rubies/ree-1.8.7-2010.01/bin/irb:17 The output from ruby -v is: ruby 1.8.7 (2009-12-24 patchlevel 248) [i686-darwin10.6.0], MBARI 0x6770, Ruby Enterprise Edition 2010.01 And the output from rails -v is: Rails 2.3.5 I've followed the basic guidelines from their documentation and from similar SA questions. But none of issues have the rails gem going missing.. And yes, we are including rails in our Gemfile =) Thank you in advance.

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  • Parsing returned array in javascript

    - by Dan
    I'm making a call to PayPal's credit card processor, and after a successful/unsuccessful transaction it returns me a string that looks like this: DoDirectPayment failed: Array ( [TIMESTAMP] = 2010%2d05%2d02T23%3a33%3a28Z [CORRELATIONID] = 8c503f5c6c861 [ACK] = Failure [VERSION] = 51%2e0 [BUILD] = 1268624 [L_ERRORCODE0] = 10527 [L_SHORTMESSAGE0] = Invalid%20Data [L_LONGMESSAGE0] = This%20transaction%20cannot%20be%20processed%2e%20Please%20enter%20a%20valid%20credit%20card%20number%20and%20type%2e [L_SEVERITYCODE0] = Error [AMT] = 90%2e00 [CURRENCYCODE] = USD ) I'm not a javascript pro, but how exactly can I turn that into a parseable array? Thank you!

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  • Issues accessing an object's array values - returns null or 0s

    - by PhatNinja
    The function below should return an array of objects with this structure: TopicFrequency = { name: "Chemistry", //This is dependent on topic data: [1,2,3,4,5,6,7,8,9,10,11,12] //This would be real data }; so when I do this: myData = this.getChartData("line"); it should return two objects: {name : "Chemistry", data : [1,2,3,4,51,12,0,0, 2,1,41, 31]} {name : "Math", data : [0,0,41,4,51,12,0,0, 2,1,41, 90]} so when I do console.log(myData); it's perfect, returns exactly this. However when I do console.log(myData[0].data) it returns all 0s, not the values. I'm not sure what this issues is known as, and my question is simple what is this problem known as? Here is the full function. Somethings were hardcoded and other variables (notable server and queryContent) removed. Those parts worked fine, it is only when manipulated/retreiving the returned array's values that I run into problems. Note this is async. so not sure if that is also part of the problem. getChartData: function (chartType) { var TopicsFrequencyArray = new Array(); timePairs = this.newIntervalSet("Month"); topicList = new Array("Chemistry", "Math");//Hard coded for now var queryCopy = { //sensitive information }; for (i = 0; i < topicList.length; i++) { var TopicFrequency = { name: null, data: this.newFilledArray(12, 0) }; j = 0; TopicFrequency.name = topicList[i]; while (j < timePairs.length) { queryCopy.filter = TopicFrequency.name; //additional queryCopy parameter changes made here var request = esri.request({ url: server, content: queryCopy, handleAs: "json", load: sucess, error: fail }); j = j + 1; function sucess(response, io) { var topicCountData = 0; query = esri.urlToObject(io.url); var dateString = query.query.fromDate.replace("%", " "); dateString = dateString.replace(/-/g, "/"); dateString = dateString.split("."); date = new Date(dateString[0]); dojo.forEach(response.features, function (feature) { if (feature.properties.count > 0) { topicCountData = feature.properties.count; } TopicFrequency.data[date.getMonth()] = topicCountData; }); } function fail(error) { j = j + 1; alert("There was an unspecified error with this request"); console.log(error); } } TopicsFrequencyArray.push(TopicFrequency); } },

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  • Website with an iframe inside

    - by user1328929
    Does anyone have any ideas how to design a website with an iframe inside , like a gallery , to browse inside urls , but still remain on the basic site ? Something like this : http://ru.trovit.com/nedvizhimost/index.php/cod.frame/url.http%253A%252F%252Fwww.mesto.ru%252Fhouse-sale%252F1165477/id_ad.123131lZaNE/type.1/what.%D0%B4%D0%BE%D0%BC%20%D0%BB%D0%B5%D0%BD%D0%B8%D0%BD%D0%B3%D1%80%D0%B0%D0%B4%D1%81%D0%BA%D0%B0%D1%8F%20%D0%BE%D0%B1%D0%BB%D0%B0%D1%81%D1%82%D1%8C/pos.2/org.1/frame_pos.2/publisher_id./referer_id.51/t.1

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  • EBCDIC to ASCII conversion. Out of bound error. In C#.

    - by mekrizzy
    I tried creating a EBCDIC to ASCII convector in C# using this general conversion order(given below). Basically the program converted from ASCII to the equivalent integer and from there into EDCDIC using the order below. Now when I try compiling this in C# and try giving a EBCDIC string(got this from another file from another computer) it is showing 'Out of Bound' exception for some of the EBCDIC character. Why is this like this?? Is it about formating?? or C# ?? or windows? Extra: I tried just printing out all the ASCII and EBCDIC characters using a loop from 0..255 numbers but still its not showing many of the EBCDIC characters. Am I missing any standards? int[] eb2as = new int[256]{ 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15, 16, 17, 18, 19,157,133, 8,135, 24, 25,146,143, 28, 29, 30, 31, 128,129,130,131,132, 10, 23, 27,136,137,138,139,140, 5, 6, 7, 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26, 32,160,161,162,163,164,165,166,167,168, 91, 46, 60, 40, 43, 33, 38,169,170,171,172,173,174,175,176,177, 93, 36, 42, 41, 59, 94, 45, 47,178,179,180,181,182,183,184,185,124, 44, 37, 95, 62, 63, 186,187,188,189,190,191,192,193,194, 96, 58, 35, 64, 39, 61, 34, 195, 97, 98, 99,100,101,102,103,104,105,196,197,198,199,200,201, 202,106,107,108,109,110,111,112,113,114,203,204,205,206,207,208, 209,126,115,116,117,118,119,120,121,122,210,211,212,213,214,215, 216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,232,233,234,235,236,237, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,238,239,240,241,242,243, 92,159, 83, 84, 85, 86, 87, 88, 89, 90,244,245,246,247,248,249, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,250,251,252,253,254,255 }; The whole code is as follows: public string convertFromEBCDICtoASCII(string inputEBCDICString, int initialPos, int endPos) { string inputSubString = inputEBCDICString.Substring(initialPos, endPos); int[] e2a = new int[256]{ 0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15, 16, 17, 18, 19,157,133, 8,135, 24, 25,146,143, 28, 29, 30, 31, 128,129,130,131,132, 10, 23, 27,136,137,138,139,140, 5, 6, 7, 144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26, 32,160,161,162,163,164,165,166,167,168, 91, 46, 60, 40, 43, 33, 38,169,170,171,172,173,174,175,176,177, 93, 36, 42, 41, 59, 94, 45, 47,178,179,180,181,182,183,184,185,124, 44, 37, 95, 62, 63, 186,187,188,189,190,191,192,193,194, 96, 58, 35, 64, 39, 61, 34, 195, 97, 98, 99,100,101,102,103,104,105,196,197,198,199,200,201, 202,106,107,108,109,110,111,112,113,114,203,204,205,206,207,208, 209,126,115,116,117,118,119,120,121,122,210,211,212,213,214,215, 216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231, 123, 65, 66, 67, 68, 69, 70, 71, 72, 73,232,233,234,235,236,237, 125, 74, 75, 76, 77, 78, 79, 80, 81, 82,238,239,240,241,242,243, 92,159, 83, 84, 85, 86, 87, 88, 89, 90,244,245,246,247,248,249, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,250,251,252,253,254,255 }; char chrItem = Convert.ToChar("0"); StringBuilder sb = new StringBuilder(); for (int i = 0; i < inputSubString.Length; i++) { try { chrItem = Convert.ToChar(inputSubString.Substring(i, 1)); sb.Append(Convert.ToChar(e2a[(int)chrItem])); sb.Append((int)chrItem); sb.Append((int)00); } catch (Exception ex) { Console.WriteLine("//" + ex.Message); return string.Empty; } } string result = sb.ToString(); sb = null; return result; }

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  • reading and extracting data from file using python

    - by parijat24
    hello , i am new to python , and I want to extract the data from this format FBpp0143497 5 151 5 157 PF00339.22 Arrestin_N Domain 1 135 149 83.4 1.1e-23 1 CL0135 FBpp0143497 183 323 183 324 PF02752.15 Arrestin_C Domain 1 137 138 58.5 6e-16 1 CL0135 FBpp0131987 60 280 51 280 PF00089.19 Trypsin Domain 14 219 219 127.7 3.7e-37 1 CL0124 to this format FBpp0143497 5 151 Arrestin_N 1.1e-23 FBpp0143497 183 323 Arrestin_C 6e-16

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  • Are 'const' variables precomputed by default in C++?

    - by Gunnar
    Suppose I have variables for positions like const float latitude = 51.+11./60.+33.0461/3600.; const float longitude = 12.+50./60.+31.9369/3600.; and use them frequently in the program. Does the compiler precompute that? (This example should not produce much overhead, but you get the point.) Bonus point for pointing out location. ;) TIA

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  • Service Discovery in WCF 4.0 &ndash; Part 1

    - by Shaun
    When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • How LINQ to Object statements work

    - by rajbk
    This post goes into detail as to now LINQ statements work when querying a collection of objects. This topic assumes you have an understanding of how generics, delegates, implicitly typed variables, lambda expressions, object/collection initializers, extension methods and the yield statement work. I would also recommend you read my previous two posts: Using Delegates in C# Part 1 Using Delegates in C# Part 2 We will start by writing some methods to filter a collection of data. Assume we have an Employee class like so: 1: public class Employee { 2: public int ID { get; set;} 3: public string FirstName { get; set;} 4: public string LastName {get; set;} 5: public string Country { get; set; } 6: } and a collection of employees like so: 1: var employees = new List<Employee> { 2: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 3: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 4: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 5: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 6: }; Filtering We wish to  find all employees that have an even ID. We could start off by writing a method that takes in a list of employees and returns a filtered list of employees with an even ID. 1: static List<Employee> GetEmployeesWithEvenID(List<Employee> employees) { 2: var filteredEmployees = new List<Employee>(); 3: foreach (Employee emp in employees) { 4: if (emp.ID % 2 == 0) { 5: filteredEmployees.Add(emp); 6: } 7: } 8: return filteredEmployees; 9: } The method can be rewritten to return an IEnumerable<Employee> using the yield return keyword. 1: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 2: foreach (Employee emp in employees) { 3: if (emp.ID % 2 == 0) { 4: yield return emp; 5: } 6: } 7: } We put these together in a console application. 1: using System; 2: using System.Collections.Generic; 3: //No System.Linq 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" }, 15: }; 16: var filteredEmployees = GetEmployeesWithEvenID(employees); 17:  18: foreach (Employee emp in filteredEmployees) { 19: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 20: emp.ID, emp.FirstName, emp.LastName, emp.Country); 21: } 22:  23: Console.ReadLine(); 24: } 25: 26: static IEnumerable<Employee> GetEmployeesWithEvenID(IEnumerable<Employee> employees) { 27: foreach (Employee emp in employees) { 28: if (emp.ID % 2 == 0) { 29: yield return emp; 30: } 31: } 32: } 33: } 34:  35: public class Employee { 36: public int ID { get; set;} 37: public string FirstName { get; set;} 38: public string LastName {get; set;} 39: public string Country { get; set; } 40: } Output: ID 2 First_Name Jim Last_Name Ashlock Country UK ID 4 First_Name Jill Last_Name Anderson Country AUS Our filtering method is too specific. Let us change it so that it is capable of doing different types of filtering and lets give our method the name Where ;-) We will add another parameter to our Where method. This additional parameter will be a delegate with the following declaration. public delegate bool Filter(Employee emp); The idea is that the delegate parameter in our Where method will point to a method that contains the logic to do our filtering thereby freeing our Where method from any dependency. The method is shown below: 1: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 2: foreach (Employee emp in employees) { 3: if (filter(emp)) { 4: yield return emp; 5: } 6: } 7: } Making the change to our app, we create a new instance of the Filter delegate on line 14 with a target set to the method EmployeeHasEvenId. Running the code will produce the same output. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, filterDelegate); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  37: public class Employee { 38: public int ID { get; set;} 39: public string FirstName { get; set;} 40: public string LastName {get; set;} 41: public string Country { get; set; } 42: } Lets use lambda expressions to inline the contents of the EmployeeHasEvenId method in place of the method. The next code snippet shows this change (see line 15).  For brevity, the Employee class declaration has been skipped. 1: public delegate bool Filter(Employee emp); 2:  3: public class Program 4: { 5: [STAThread] 6: static void Main(string[] args) 7: { 8: var employees = new List<Employee> { 9: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 10: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 11: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 12: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 13: }; 14: var filterDelegate = new Filter(EmployeeHasEvenId); 15: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 16:  17: foreach (Employee emp in filteredEmployees) { 18: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 19: emp.ID, emp.FirstName, emp.LastName, emp.Country); 20: } 21: Console.ReadLine(); 22: } 23: 24: static bool EmployeeHasEvenId(Employee emp) { 25: return emp.ID % 2 == 0; 26: } 27: 28: static IEnumerable<Employee> Where(IEnumerable<Employee> employees, Filter filter) { 29: foreach (Employee emp in employees) { 30: if (filter(emp)) { 31: yield return emp; 32: } 33: } 34: } 35: } 36:  The output displays the same two employees.  Our Where method is too restricted since it works with a collection of Employees only. Lets change it so that it works with any IEnumerable<T>. In addition, you may recall from my previous post,  that .NET 3.5 comes with a lot of predefined delegates including public delegate TResult Func<T, TResult>(T arg); We will get rid of our Filter delegate and use the one above instead. We apply these two changes to our code. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14:  15: foreach (Employee emp in filteredEmployees) { 16: Console.WriteLine("ID {0} First_Name {1} Last_Name {2} Country {3}", 17: emp.ID, emp.FirstName, emp.LastName, emp.Country); 18: } 19: Console.ReadLine(); 20: } 21: 22: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 23: foreach (var x in source) { 24: if (filter(x)) { 25: yield return x; 26: } 27: } 28: } 29: } We have successfully implemented a way to filter any IEnumerable<T> based on a  filter criteria. Projection Now lets enumerate on the items in the IEnumerable<Employee> we got from the Where method and copy them into a new IEnumerable<EmployeeFormatted>. The EmployeeFormatted class will only have a FullName and ID property. 1: public class EmployeeFormatted { 2: public int ID { get; set; } 3: public string FullName {get; set;} 4: } We could “project” our existing IEnumerable<Employee> into a new collection of IEnumerable<EmployeeFormatted> with the help of a new method. We will call this method Select ;-) 1: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 2: foreach (var emp in employees) { 3: yield return new EmployeeFormatted { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; 7: } 8: } The changes are applied to our app. 1: public class Program 2: { 3: [STAThread] 4: static void Main(string[] args) 5: { 6: var employees = new List<Employee> { 7: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 8: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 9: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 10: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 11: }; 12:  13: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 14: var formattedEmployees = Select(filteredEmployees); 15:  16: foreach (EmployeeFormatted emp in formattedEmployees) { 17: Console.WriteLine("ID {0} Full_Name {1}", 18: emp.ID, emp.FullName); 19: } 20: Console.ReadLine(); 21: } 22:  23: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 24: foreach (var x in source) { 25: if (filter(x)) { 26: yield return x; 27: } 28: } 29: } 30: 31: static IEnumerable<EmployeeFormatted> Select(IEnumerable<Employee> employees) { 32: foreach (var emp in employees) { 33: yield return new EmployeeFormatted { 34: ID = emp.ID, 35: FullName = emp.LastName + ", " + emp.FirstName 36: }; 37: } 38: } 39: } 40:  41: public class Employee { 42: public int ID { get; set;} 43: public string FirstName { get; set;} 44: public string LastName {get; set;} 45: public string Country { get; set; } 46: } 47:  48: public class EmployeeFormatted { 49: public int ID { get; set; } 50: public string FullName {get; set;} 51: } Output: ID 2 Full_Name Ashlock, Jim ID 4 Full_Name Anderson, Jill We have successfully selected employees who have an even ID and then shaped our data with the help of the Select method so that the final result is an IEnumerable<EmployeeFormatted>.  Lets make our Select method more generic so that the user is given the freedom to shape what the output would look like. We can do this, like before, with lambda expressions. Our Select method is changed to accept a delegate as shown below. TSource will be the type of data that comes in and TResult will be the type the user chooses (shape of data) as returned from the selector delegate. 1:  2: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 3: foreach (var x in source) { 4: yield return selector(x); 5: } 6: } We see the new changes to our app. On line 15, we use lambda expression to specify the shape of the data. In this case the shape will be of type EmployeeFormatted. 1:  2: public class Program 3: { 4: [STAThread] 5: static void Main(string[] args) 6: { 7: var employees = new List<Employee> { 8: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 9: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 10: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 11: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 12: }; 13:  14: var filteredEmployees = Where(employees, emp => emp.ID % 2 == 0); 15: var formattedEmployees = Select(filteredEmployees, (emp) => 16: new EmployeeFormatted { 17: ID = emp.ID, 18: FullName = emp.LastName + ", " + emp.FirstName 19: }); 20:  21: foreach (EmployeeFormatted emp in formattedEmployees) { 22: Console.WriteLine("ID {0} Full_Name {1}", 23: emp.ID, emp.FullName); 24: } 25: Console.ReadLine(); 26: } 27: 28: static IEnumerable<T> Where<T>(IEnumerable<T> source, Func<T, bool> filter) { 29: foreach (var x in source) { 30: if (filter(x)) { 31: yield return x; 32: } 33: } 34: } 35: 36: static IEnumerable<TResult> Select<TSource, TResult>(IEnumerable<TSource> source, Func<TSource, TResult> selector) { 37: foreach (var x in source) { 38: yield return selector(x); 39: } 40: } 41: } The code outputs the same result as before. On line 14 we filter our data and on line 15 we project our data. What if we wanted to be more expressive and concise? We could combine both line 14 and 15 into one line as shown below. Assuming you had to perform several operations like this on our collection, you would end up with some very unreadable code! 1: var formattedEmployees = Select(Where(employees, emp => emp.ID % 2 == 0), (emp) => 2: new EmployeeFormatted { 3: ID = emp.ID, 4: FullName = emp.LastName + ", " + emp.FirstName 5: }); A cleaner way to write this would be to give the appearance that the Select and Where methods were part of the IEnumerable<T>. This is exactly what extension methods give us. Extension methods have to be defined in a static class. Let us make the Select and Where extension methods on IEnumerable<T> 1: public static class MyExtensionMethods { 2: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 3: foreach (var x in source) { 4: if (filter(x)) { 5: yield return x; 6: } 7: } 8: } 9: 10: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 11: foreach (var x in source) { 12: yield return selector(x); 13: } 14: } 15: } The creation of the extension method makes the syntax much cleaner as shown below. We can write as many extension methods as we want and keep on chaining them using this technique. 1: var formattedEmployees = employees 2: .Where(emp => emp.ID % 2 == 0) 3: .Select (emp => new EmployeeFormatted { ID = emp.ID, FullName = emp.LastName + ", " + emp.FirstName }); Making these changes and running our code produces the same result. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new EmployeeFormatted { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (EmployeeFormatted emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } 55:  56: public class EmployeeFormatted { 57: public int ID { get; set; } 58: public string FullName {get; set;} 59: } Let’s change our code to return a collection of anonymous types and get rid of the EmployeeFormatted type. We see that the code produces the same output. 1: using System; 2: using System.Collections.Generic; 3:  4: public class Program 5: { 6: [STAThread] 7: static void Main(string[] args) 8: { 9: var employees = new List<Employee> { 10: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 11: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 12: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 13: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 14: }; 15:  16: var formattedEmployees = employees 17: .Where(emp => emp.ID % 2 == 0) 18: .Select (emp => 19: new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: } 23: ); 24:  25: foreach (var emp in formattedEmployees) { 26: Console.WriteLine("ID {0} Full_Name {1}", 27: emp.ID, emp.FullName); 28: } 29: Console.ReadLine(); 30: } 31: } 32:  33: public static class MyExtensionMethods { 34: public static IEnumerable<T> Where<T>(this IEnumerable<T> source, Func<T, bool> filter) { 35: foreach (var x in source) { 36: if (filter(x)) { 37: yield return x; 38: } 39: } 40: } 41: 42: public static IEnumerable<TResult> Select<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector) { 43: foreach (var x in source) { 44: yield return selector(x); 45: } 46: } 47: } 48:  49: public class Employee { 50: public int ID { get; set;} 51: public string FirstName { get; set;} 52: public string LastName {get; set;} 53: public string Country { get; set; } 54: } To be more expressive, C# allows us to write our extension method calls as a query expression. Line 16 can be rewritten a query expression like so: 1: var formattedEmployees = from emp in employees 2: where emp.ID % 2 == 0 3: select new { 4: ID = emp.ID, 5: FullName = emp.LastName + ", " + emp.FirstName 6: }; When the compiler encounters an expression like the above, it simply rewrites it as calls to our extension methods.  So far we have been using our extension methods. The System.Linq namespace contains several extension methods for objects that implement the IEnumerable<T>. You can see a listing of these methods in the Enumerable class in the System.Linq namespace. Let’s get rid of our extension methods (which I purposefully wrote to be of the same signature as the ones in the Enumerable class) and use the ones provided in the Enumerable class. Our final code is shown below: 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; //Added 4:  5: public class Program 6: { 7: [STAThread] 8: static void Main(string[] args) 9: { 10: var employees = new List<Employee> { 11: new Employee { ID = 1, FirstName = "John", LastName = "Wright", Country = "USA" }, 12: new Employee { ID = 2, FirstName = "Jim", LastName = "Ashlock", Country = "UK" }, 13: new Employee { ID = 3, FirstName = "Jane", LastName = "Jackson", Country = "CHE" }, 14: new Employee { ID = 4, FirstName = "Jill", LastName = "Anderson", Country = "AUS" } 15: }; 16:  17: var formattedEmployees = from emp in employees 18: where emp.ID % 2 == 0 19: select new { 20: ID = emp.ID, 21: FullName = emp.LastName + ", " + emp.FirstName 22: }; 23:  24: foreach (var emp in formattedEmployees) { 25: Console.WriteLine("ID {0} Full_Name {1}", 26: emp.ID, emp.FullName); 27: } 28: Console.ReadLine(); 29: } 30: } 31:  32: public class Employee { 33: public int ID { get; set;} 34: public string FirstName { get; set;} 35: public string LastName {get; set;} 36: public string Country { get; set; } 37: } 38:  39: public class EmployeeFormatted { 40: public int ID { get; set; } 41: public string FullName {get; set;} 42: } This post has shown you a basic overview of LINQ to Objects work by showning you how an expression is converted to a sequence of calls to extension methods when working directly with objects. It gets more interesting when working with LINQ to SQL where an expression tree is constructed – an in memory data representation of the expression. The C# compiler compiles these expressions into code that builds an expression tree at runtime. The provider can then traverse the expression tree and generate the appropriate SQL query. You can read more about expression trees in this MSDN article.

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  • Node.js Adventure - Storage Services and Service Runtime

    - by Shaun
    When I described on how to host a Node.js application on Windows Azure, one of questions might be raised about how to consume the vary Windows Azure services, such as the storage, service bus, access control, etc.. Interact with windows azure services is available in Node.js through the Windows Azure Node.js SDK, which is a module available in NPM. In this post I would like to describe on how to use Windows Azure Storage (a.k.a. WAS) as well as the service runtime.   Consume Windows Azure Storage Let’s firstly have a look on how to consume WAS through Node.js. As we know in the previous post we can host Node.js application on Windows Azure Web Site (a.k.a. WAWS) as well as Windows Azure Cloud Service (a.k.a. WACS). In theory, WAWS is also built on top of WACS worker roles with some more features. Hence in this post I will only demonstrate for hosting in WACS worker role. The Node.js code can be used when consuming WAS when hosted on WAWS. But since there’s no roles in WAWS, the code for consuming service runtime mentioned in the next section cannot be used for WAWS node application. We can use the solution that I created in my last post. Alternatively we can create a new windows azure project in Visual Studio with a worker role, add the “node.exe” and “index.js” and install “express” and “node-sqlserver” modules, make all files as “Copy always”. In order to use windows azure services we need to have Windows Azure Node.js SDK, as knows as a module named “azure” which can be installed through NPM. Once we downloaded and installed, we need to include them in our worker role project and make them as “Copy always”. You can use my “Copy all always” tool mentioned in my last post to update the currently worker role project file. You can also find the source code of this tool here. The source code of Windows Azure SDK for Node.js can be found in its GitHub page. It contains two parts. One is a CLI tool which provides a cross platform command line package for Mac and Linux to manage WAWS and Windows Azure Virtual Machines (a.k.a. WAVM). The other is a library for managing and consuming vary windows azure services includes tables, blobs, queues, service bus and the service runtime. I will not cover all of them but will only demonstrate on how to use tables and service runtime information in this post. You can find the full document of this SDK here. Back to Visual Studio and open the “index.js”, let’s continue our application from the last post, which was working against Windows Azure SQL Database (a.k.a. WASD). The code should looks like this. 1: var express = require("express"); 2: var sql = require("node-sqlserver"); 3:  4: var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd={PASSWORD};Encrypt=yes;Connection Timeout=30;"; 5: var port = 80; 6:  7: var app = express(); 8:  9: app.configure(function () { 10: app.use(express.bodyParser()); 11: }); 12:  13: app.get("/", function (req, res) { 14: sql.open(connectionString, function (err, conn) { 15: if (err) { 16: console.log(err); 17: res.send(500, "Cannot open connection."); 18: } 19: else { 20: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 21: if (err) { 22: console.log(err); 23: res.send(500, "Cannot retrieve records."); 24: } 25: else { 26: res.json(results); 27: } 28: }); 29: } 30: }); 31: }); 32:  33: app.get("/text/:key/:culture", function (req, res) { 34: sql.open(connectionString, function (err, conn) { 35: if (err) { 36: console.log(err); 37: res.send(500, "Cannot open connection."); 38: } 39: else { 40: var key = req.params.key; 41: var culture = req.params.culture; 42: var command = "SELECT * FROM [Resource] WHERE [Key] = '" + key + "' AND [Culture] = '" + culture + "'"; 43: conn.queryRaw(command, function (err, results) { 44: if (err) { 45: console.log(err); 46: res.send(500, "Cannot retrieve records."); 47: } 48: else { 49: res.json(results); 50: } 51: }); 52: } 53: }); 54: }); 55:  56: app.get("/sproc/:key/:culture", function (req, res) { 57: sql.open(connectionString, function (err, conn) { 58: if (err) { 59: console.log(err); 60: res.send(500, "Cannot open connection."); 61: } 62: else { 63: var key = req.params.key; 64: var culture = req.params.culture; 65: var command = "EXEC GetItem '" + key + "', '" + culture + "'"; 66: conn.queryRaw(command, function (err, results) { 67: if (err) { 68: console.log(err); 69: res.send(500, "Cannot retrieve records."); 70: } 71: else { 72: res.json(results); 73: } 74: }); 75: } 76: }); 77: }); 78:  79: app.post("/new", function (req, res) { 80: var key = req.body.key; 81: var culture = req.body.culture; 82: var val = req.body.val; 83:  84: sql.open(connectionString, function (err, conn) { 85: if (err) { 86: console.log(err); 87: res.send(500, "Cannot open connection."); 88: } 89: else { 90: var command = "INSERT INTO [Resource] VALUES ('" + key + "', '" + culture + "', N'" + val + "')"; 91: conn.queryRaw(command, function (err, results) { 92: if (err) { 93: console.log(err); 94: res.send(500, "Cannot retrieve records."); 95: } 96: else { 97: res.send(200, "Inserted Successful"); 98: } 99: }); 100: } 101: }); 102: }); 103:  104: app.listen(port); Now let’s create a new function, copy the records from WASD to table service. 1. Delete the table named “resource”. 2. Create a new table named “resource”. These 2 steps ensures that we have an empty table. 3. Load all records from the “resource” table in WASD. 4. For each records loaded from WASD, insert them into the table one by one. 5. Prompt to user when finished. In order to use table service we need the storage account and key, which can be found from the developer portal. Just select the storage account and click the Manage Keys button. Then create two local variants in our Node.js application for the storage account name and key. Since we need to use WAS we need to import the azure module. Also I created another variant stored the table name. In order to work with table service I need to create the storage client for table service. This is very similar as the Windows Azure SDK for .NET. As the code below I created a new variant named “client” and use “createTableService”, specified my storage account name and key. 1: var azure = require("azure"); 2: var storageAccountName = "synctile"; 3: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 4: var tableName = "resource"; 5: var client = azure.createTableService(storageAccountName, storageAccountKey); Now create a new function for URL “/was/init” so that we can trigger it through browser. Then in this function we will firstly load all records from WASD. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: } 18: } 19: }); 20: } 21: }); 22: }); When we succeed loaded all records we can start to transform them into table service. First I need to recreate the table in table service. This can be done by deleting and creating the table through table client I had just created previously. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: } 27: }); 28: }); 29: } 30: } 31: }); 32: } 33: }); 34: }); As you can see, the azure SDK provide its methods in callback pattern. In fact, almost all modules in Node.js use the callback pattern. For example, when I deleted a table I invoked “deleteTable” method, provided the name of the table and a callback function which will be performed when the table had been deleted or failed. Underlying, the azure module will perform the table deletion operation in POSIX async threads pool asynchronously. And once it’s done the callback function will be performed. This is the reason we need to nest the table creation code inside the deletion function. If we perform the table creation code after the deletion code then they will be invoked in parallel. Next, for each records in WASD I created an entity and then insert into the table service. Finally I send the response to the browser. Can you find a bug in the code below? I will describe it later in this post. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: for (var i = 0; i < results.rows.length; i++) { 27: var entity = { 28: "PartitionKey": results.rows[i][1], 29: "RowKey": results.rows[i][0], 30: "Value": results.rows[i][2] 31: }; 32: client.insertEntity(tableName, entity, function (error) { 33: if (error) { 34: error["target"] = "insertEntity"; 35: res.send(500, error); 36: } 37: else { 38: console.log("entity inserted"); 39: } 40: }); 41: } 42: // send the 43: console.log("all done"); 44: res.send(200, "All done!"); 45: } 46: }); 47: }); 48: } 49: } 50: }); 51: } 52: }); 53: }); Now we can publish it to the cloud and have a try. But normally we’d better test it at the local emulator first. In Node.js SDK there are three build-in properties which provides the account name, key and host address for local storage emulator. We can use them to initialize our table service client. We also need to change the SQL connection string to let it use my local database. The code will be changed as below. 1: // windows azure sql database 2: //var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd=eszqu94XZY;Encrypt=yes;Connection Timeout=30;"; 3: // sql server 4: var connectionString = "Driver={SQL Server Native Client 11.0};Server={.};Database={Caspar};Trusted_Connection={Yes};"; 5:  6: var azure = require("azure"); 7: var storageAccountName = "synctile"; 8: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 9: var tableName = "resource"; 10: // windows azure storage 11: //var client = azure.createTableService(storageAccountName, storageAccountKey); 12: // local storage emulator 13: var client = azure.createTableService(azure.ServiceClient.DEVSTORE_STORAGE_ACCOUNT, azure.ServiceClient.DEVSTORE_STORAGE_ACCESS_KEY, azure.ServiceClient.DEVSTORE_TABLE_HOST); Now let’s run the application and navigate to “localhost:12345/was/init” as I hosted it on port 12345. We can find it transformed the data from my local database to local table service. Everything looks fine. But there is a bug in my code. If we have a look on the Node.js command window we will find that it sent response before all records had been inserted, which is not what I expected. The reason is that, as I mentioned before, Node.js perform all IO operations in non-blocking model. When we inserted the records we executed the table service insert method in parallel, and the operation of sending response was also executed in parallel, even though I wrote it at the end of my logic. The correct logic should be, when all entities had been copied to table service with no error, then I will send response to the browser, otherwise I should send error message to the browser. To do so I need to import another module named “async”, which helps us to coordinate our asynchronous code. Install the module and import it at the beginning of the code. Then we can use its “forEach” method for the asynchronous code of inserting table entities. The first argument of “forEach” is the array that will be performed. The second argument is the operation for each items in the array. And the third argument will be invoked then all items had been performed or any errors occurred. Here we can send our response to browser. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: async.forEach(results.rows, 26: // transform the records 27: function (row, callback) { 28: var entity = { 29: "PartitionKey": row[1], 30: "RowKey": row[0], 31: "Value": row[2] 32: }; 33: client.insertEntity(tableName, entity, function (error) { 34: if (error) { 35: callback(error); 36: } 37: else { 38: console.log("entity inserted."); 39: callback(null); 40: } 41: }); 42: }, 43: // send reponse 44: function (error) { 45: if (error) { 46: error["target"] = "insertEntity"; 47: res.send(500, error); 48: } 49: else { 50: console.log("all done"); 51: res.send(200, "All done!"); 52: } 53: } 54: ); 55: } 56: }); 57: }); 58: } 59: } 60: }); 61: } 62: }); 63: }); Run it locally and now we can find the response was sent after all entities had been inserted. Query entities against table service is simple as well. Just use the “queryEntity” method from the table service client and providing the partition key and row key. We can also provide a complex query criteria as well, for example the code here. In the code below I queried an entity by the partition key and row key, and return the proper localization value in response. 1: app.get("/was/:key/:culture", function (req, res) { 2: var key = req.params.key; 3: var culture = req.params.culture; 4: client.queryEntity(tableName, culture, key, function (error, entity) { 5: if (error) { 6: res.send(500, error); 7: } 8: else { 9: res.json(entity); 10: } 11: }); 12: }); And then tested it on local emulator. Finally if we want to publish this application to the cloud we should change the database connection string and storage account. For more information about how to consume blob and queue service, as well as the service bus please refer to the MSDN page.   Consume Service Runtime As I mentioned above, before we published our application to the cloud we need to change the connection string and account information in our code. But if you had played with WACS you should have known that the service runtime provides the ability to retrieve configuration settings, endpoints and local resource information at runtime. Which means we can have these values defined in CSCFG and CSDEF files and then the runtime should be able to retrieve the proper values. For example we can add some role settings though the property window of the role, specify the connection string and storage account for cloud and local. And the can also use the endpoint which defined in role environment to our Node.js application. In Node.js SDK we can get an object from “azure.RoleEnvironment”, which provides the functionalities to retrieve the configuration settings and endpoints, etc.. In the code below I defined the connection string variants and then use the SDK to retrieve and initialize the table client. 1: var connectionString = ""; 2: var storageAccountName = ""; 3: var storageAccountKey = ""; 4: var tableName = ""; 5: var client; 6:  7: azure.RoleEnvironment.getConfigurationSettings(function (error, settings) { 8: if (error) { 9: console.log("ERROR: getConfigurationSettings"); 10: console.log(JSON.stringify(error)); 11: } 12: else { 13: console.log(JSON.stringify(settings)); 14: connectionString = settings["SqlConnectionString"]; 15: storageAccountName = settings["StorageAccountName"]; 16: storageAccountKey = settings["StorageAccountKey"]; 17: tableName = settings["TableName"]; 18:  19: console.log("connectionString = %s", connectionString); 20: console.log("storageAccountName = %s", storageAccountName); 21: console.log("storageAccountKey = %s", storageAccountKey); 22: console.log("tableName = %s", tableName); 23:  24: client = azure.createTableService(storageAccountName, storageAccountKey); 25: } 26: }); In this way we don’t need to amend the code for the configurations between local and cloud environment since the service runtime will take care of it. At the end of the code we will listen the application on the port retrieved from SDK as well. 1: azure.RoleEnvironment.getCurrentRoleInstance(function (error, instance) { 2: if (error) { 3: console.log("ERROR: getCurrentRoleInstance"); 4: console.log(JSON.stringify(error)); 5: } 6: else { 7: console.log(JSON.stringify(instance)); 8: if (instance["endpoints"] && instance["endpoints"]["nodejs"]) { 9: var endpoint = instance["endpoints"]["nodejs"]; 10: app.listen(endpoint["port"]); 11: } 12: else { 13: app.listen(8080); 14: } 15: } 16: }); But if we tested the application right now we will find that it cannot retrieve any values from service runtime. This is because by default, the entry point of this role was defined to the worker role class. In windows azure environment the service runtime will open a named pipeline to the entry point instance, so that it can connect to the runtime and retrieve values. But in this case, since the entry point was worker role and the Node.js was opened inside the role, the named pipeline was established between our worker role class and service runtime, so our Node.js application cannot use it. To fix this problem we need to open the CSDEF file under the azure project, add a new element named Runtime. Then add an element named EntryPoint which specify the Node.js command line. So that the Node.js application will have the connection to service runtime, then it’s able to read the configurations. Start the Node.js at local emulator we can find it retrieved the connections, storage account for local. And if we publish our application to azure then it works with WASD and storage service through the configurations for cloud.   Summary In this post I demonstrated how to use Windows Azure SDK for Node.js to interact with storage service, especially the table service. I also demonstrated on how to use WACS service runtime, how to retrieve the configuration settings and the endpoint information. And in order to make the service runtime available to my Node.js application I need to create an entry point element in CSDEF file and set “node.exe” as the entry point. I used five posts to introduce and demonstrate on how to run a Node.js application on Windows platform, how to use Windows Azure Web Site and Windows Azure Cloud Service worker role to host our Node.js application. I also described how to work with other services provided by Windows Azure platform through Windows Azure SDK for Node.js. Node.js is a very new and young network application platform. But since it’s very simple and easy to learn and deploy, as well as, it utilizes single thread non-blocking IO model, Node.js became more and more popular on web application and web service development especially for those IO sensitive projects. And as Node.js is very good at scaling-out, it’s more useful on cloud computing platform. Use Node.js on Windows platform is new, too. The modules for SQL database and Windows Azure SDK are still under development and enhancement. It doesn’t support SQL parameter in “node-sqlserver”. It does support using storage connection string to create the storage client in “azure”. But Microsoft is working on make them easier to use, working on add more features and functionalities.   PS, you can download the source code here. You can download the source code of my “Copy all always” tool here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • Jframe using multiple classes?

    - by user2945880
    and im trying to make it so it can show multiple classes at once Jframe: import javax.swing.JFrame; import java.awt.BorderLayout; public class Concert { public static void main(String[] args) { JFrame frame = new JFrame(); frame.setSize(1000, 800); frame.setTitle("Concert!"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); Concertbackground component = new Concertbackground(); BandComponent component1 = new BandComponent(); frame.add(component, BorderLayout.NORTH); frame.add(component1, BorderLayout.CENTER); frame.setVisible(true); } } These are the two classes mentioned in the Jframe: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Rectangle; import java.awt.geom.Ellipse2D; import java.awt.geom.Line2D; import javax.swing.JComponent; import java.awt.Polygon; /* BandComponent.java Justin Walker 10/27/13 */ public class BandComponent extends JComponent { public void paintComponent(Graphics g) { // Recover Graphics2D Graphics2D g2 = (Graphics2D) g; int xScale = 250; int yScale = 100; int x = 343; int y = 343; //singer Polygon sing = new Polygon(); sing.addPoint(667 ,208 + xScale); sing.addPoint(676,213 + xScale); sing.addPoint(678,217 + xScale); sing.addPoint(682,221 + xScale); sing.addPoint(681,224 + xScale); sing.addPoint(680,231 + xScale); sing.addPoint(676,242 + xScale); sing.addPoint(672,244 + xScale); sing.addPoint(672,250 + xScale); sing.addPoint(682,248 + xScale); sing.addPoint(713,244 + xScale); sing.addPoint(734,247 + xScale); sing.addPoint(750,247 + xScale); sing.addPoint(794,232 + xScale); sing.addPoint(800,231 + xScale); sing.addPoint(801,223 + xScale); sing.addPoint(807,219 + xScale); sing.addPoint(806,221 + xScale); sing.addPoint(806,229 + xScale); sing.addPoint(818,222 + xScale); sing.addPoint(820,223 + xScale); sing.addPoint(825,227 + xScale); sing.addPoint(825,240 + xScale); sing.addPoint(817,243 + xScale); sing.addPoint(807,245 + xScale); sing.addPoint(803,247 + xScale); sing.addPoint(801,252 + xScale); sing.addPoint(781,257 + xScale); sing.addPoint(762,264 + xScale); sing.addPoint(734,271 + xScale); sing.addPoint(701,286 + xScale); sing.addPoint(691,296 + xScale); sing.addPoint(693,311 + xScale); sing.addPoint(690,317 + xScale); sing.addPoint(690,335 + xScale); sing.addPoint(691,339 + xScale); sing.addPoint(689,343 + xScale); sing.addPoint(712,382 + xScale); sing.addPoint(725,400 + xScale); sing.addPoint(731,418 + xScale); sing.addPoint(731,428 + xScale); sing.addPoint(738,454 + xScale); sing.addPoint(741,460 + xScale); sing.addPoint(746,468 + xScale); sing.addPoint(766,468 + xScale); sing.addPoint(771,481 + xScale);// sing.addPoint(723,482 + xScale); sing.addPoint(720,462 + xScale); sing.addPoint(718,454 + xScale); sing.addPoint(709,436 + xScale); sing.addPoint(703,436 + xScale); sing.addPoint(699,417 + xScale); sing.addPoint(686,396 + xScale); sing.addPoint(678,395 + xScale); sing.addPoint(676,437 + xScale); sing.addPoint(673,439 + xScale); sing.addPoint(638,435 + xScale); sing.addPoint(640,398 + xScale); sing.addPoint(634,410 + xScale); sing.addPoint(625,416 + xScale); sing.addPoint(622,436 + xScale); sing.addPoint(622,443 + xScale); sing.addPoint(615,447 + xScale); sing.addPoint(609,456 + xScale); sing.addPoint(606,481 + xScale);// sing.addPoint(557,481 + xScale); sing.addPoint(560,467 + xScale); sing.addPoint(579,467 + xScale); sing.addPoint(587,464 + xScale); sing.addPoint(593,452 + xScale); sing.addPoint(594,441 + xScale); sing.addPoint(592,434 + xScale); sing.addPoint(600,416 + xScale); sing.addPoint(608,405 + xScale); sing.addPoint(609,394 + xScale); sing.addPoint(617,376 + xScale); sing.addPoint(619,363 + xScale); sing.addPoint(632,334 + xScale); sing.addPoint(637,324 + xScale); sing.addPoint(635,314 + xScale); sing.addPoint(639,296 + xScale); sing.addPoint(627,285 + xScale); sing.addPoint(600,279 + xScale); sing.addPoint(582,278 + xScale); sing.addPoint(575,275 + xScale); sing.addPoint(546,256 + xScale); sing.addPoint(536,252 + xScale); sing.addPoint(533,350 + xScale); sing.addPoint(534,361 + xScale); sing.addPoint(532,367 + xScale); sing.addPoint(529,369 + xScale); sing.addPoint(524,363 + xScale); sing.addPoint(525,355 + xScale); sing.addPoint(531,254 + xScale); sing.addPoint(527,249 + xScale); sing.addPoint(527,242 + xScale); sing.addPoint(529,237 + xScale); sing.addPoint(532,237 + xScale); sing.addPoint(536,178 + xScale); sing.addPoint(534,129 + xScale); sing.addPoint(535,123 + xScale); sing.addPoint(541,120 + xScale); sing.addPoint(545,123 + xScale); sing.addPoint(547,131 + xScale); sing.addPoint(545,173 + xScale); sing.addPoint(538,233 + xScale); sing.addPoint(549,239 + xScale); sing.addPoint(558,241 + xScale); sing.addPoint(585,257 + xScale); sing.addPoint(599,257 + xScale); sing.addPoint(627,254 + xScale); sing.addPoint(647,251 + xScale); sing.addPoint(653,248 + xScale); sing.addPoint(652,235 + xScale); sing.addPoint(648,226 + xScale); sing.addPoint(652,218 + xScale); sing.addPoint(661,212 + xScale); g2.setColor(Color.black); g2.fill(sing); g2.draw(sing); //guitar Polygon guitar = new Polygon(); guitar.addPoint(148,28); guitar.addPoint(158,32); guitar.addPoint(164,38); guitar.addPoint(168,46); guitar.addPoint(169,52); guitar.addPoint(167,60); guitar.addPoint(164,65); guitar.addPoint(165,70); guitar.addPoint(161,76); guitar.addPoint(158,92); guitar.addPoint(162,97); guitar.addPoint(161,102); guitar.addPoint(158,106); guitar.addPoint(155,108); guitar.addPoint(151,127); guitar.addPoint(152,133); guitar.addPoint(155,137); guitar.addPoint(151,146); guitar.addPoint(153,147); guitar.addPoint(160,142); guitar.addPoint(162,133); guitar.addPoint(162,123); guitar.addPoint(161,113); guitar.addPoint(162,110); guitar.addPoint(164,117); guitar.addPoint(169,131); guitar.addPoint(171,144); guitar.addPoint(170,159); guitar.addPoint(166,167); guitar.addPoint(166,171); guitar.addPoint(174,174); guitar.addPoint(183,184); guitar.addPoint(191,195); guitar.addPoint(196,198); guitar.addPoint(198,200); guitar.addPoint(199,210); guitar.addPoint(211,225); guitar.addPoint(212,233); guitar.addPoint(220,248); guitar.addPoint(233,260); guitar.addPoint(245,266); guitar.addPoint(248,268); guitar.addPoint(249,277); guitar.addPoint(205,275); guitar.addPoint(204,262); guitar.addPoint(187,238); guitar.addPoint(178,224); guitar.addPoint(177,216); guitar.addPoint(156,201); guitar.addPoint(146,197); guitar.addPoint(134,211); guitar.addPoint(128,229); guitar.addPoint(125,244);// guitar.addPoint(121,246); guitar.addPoint(107,248); guitar.addPoint(100,252); guitar.addPoint(97,258); guitar.addPoint(96,253); guitar.addPoint(89,258); guitar.addPoint(65,267); guitar.addPoint(63,274); guitar.addPoint(64,283); guitar.addPoint(41,282); guitar.addPoint(44,270); guitar.addPoint(47,264); guitar.addPoint(51,255); guitar.addPoint(73,238); guitar.addPoint(79,228); guitar.addPoint(97,222); guitar.addPoint(101,204); guitar.addPoint(102,181); guitar.addPoint(100,170); guitar.addPoint(95,161); guitar.addPoint(97,154); guitar.addPoint(91,152); guitar.addPoint(77,131); guitar.addPoint(65,123); guitar.addPoint(61,105); guitar.addPoint(64,94); guitar.addPoint(72,91); guitar.addPoint(78,82); guitar.addPoint(78,76); guitar.addPoint(70,73); guitar.addPoint(70,67); guitar.addPoint(93,51); guitar.addPoint(101,48); guitar.addPoint(111,52); guitar.addPoint(118,59); guitar.addPoint(119,70); guitar.addPoint(117,78); guitar.addPoint(113,79); guitar.addPoint(112,86); guitar.addPoint(111,88); guitar.addPoint(109,89); guitar.addPoint(109,92); guitar.addPoint(122,99);// guitar.addPoint(124,99); guitar.addPoint(133,96); guitar.addPoint(145,93); //guitar.addPoint(138,124); guitar.addPoint(150,69); guitar.addPoint(150,62); guitar.addPoint(155,58); guitar.addPoint(154,53); guitar.addPoint(149,50); guitar.addPoint(154,46); guitar.addPoint(153,38); guitar.addPoint(147,28); g2.setColor(Color.black); g2.fill(guitar); g2.draw(guitar); Polygon guitar2 = new Polygon (); guitar2.addPoint(141,108); guitar2.addPoint(139,126); guitar2.addPoint(135,122); guitar2.addPoint(128,122); guitar2.addPoint(129,116); guitar2.addPoint(143,108); g2.setColor(Color.white); g2.fill(guitar2); g2.draw(guitar2); //bass guitar Polygon bassgt = new Polygon (); bassgt.addPoint(871,21); bassgt.addPoint(879,24); bassgt.addPoint(885,32); bassgt.addPoint(886,42); bassgt.addPoint(895,47); bassgt.addPoint(904,56); bassgt.addPoint(907,69); bassgt.addPoint(909,83); bassgt.addPoint(910,91); bassgt.addPoint(941,81); bassgt.addPoint(946,75); bassgt.addPoint(945,67); bassgt.addPoint(950,67); bassgt.addPoint(955,75); bassgt.addPoint(960,68); bassgt.addPoint(963,74); bassgt.addPoint(967,72); bassgt.addPoint(971,66); bassgt.addPoint(973,70); bassgt.addPoint(981,67); bassgt.addPoint(984,71); bassgt.addPoint(982,76); bassgt.addPoint(987,80); bassgt.addPoint(986,82); bassgt.addPoint(980,83); bassgt.addPoint(979,90); bassgt.addPoint(974,85); bassgt.addPoint(970,86); bassgt.addPoint(973,91); bassgt.addPoint(965,86); bassgt.addPoint(960,90); bassgt.addPoint(961,100); bassgt.addPoint(955,92); bassgt.addPoint(944,91); bassgt.addPoint(907,103); bassgt.addPoint(906,109); bassgt.addPoint(893,114); bassgt.addPoint(895,123); bassgt.addPoint(900,131); bassgt.addPoint(904,134); bassgt.addPoint(908,145); bassgt.addPoint(911,159); bassgt.addPoint(918,171); bassgt.addPoint(919,190); bassgt.addPoint(923,198); bassgt.addPoint(919,201); bassgt.addPoint(919,210); bassgt.addPoint(927,220); bassgt.addPoint(942,226); bassgt.addPoint(944,234); bassgt.addPoint(909,230); bassgt.addPoint(905,214); bassgt.addPoint(899,204); bassgt.addPoint(893,203); bassgt.addPoint(889,171); bassgt.addPoint(877,151); bassgt.addPoint(861,152); bassgt.addPoint(852,169); bassgt.addPoint(849,203); bassgt.addPoint(841,210); bassgt.addPoint(840,228); bassgt.addPoint(828,233); bassgt.addPoint(806,235); bassgt.addPoint(805,228); bassgt.addPoint(822,219); bassgt.addPoint(824,204); bassgt.addPoint(817,201); bassgt.addPoint(822,196); bassgt.addPoint(822,184); bassgt.addPoint(828,162); bassgt.addPoint(829,152); bassgt.addPoint(820,149); bassgt.addPoint(811,144); bassgt.addPoint(806,134); bassgt.addPoint(805,117); bassgt.addPoint(820,107); bassgt.addPoint(819,89); bassgt.addPoint(811,83); bassgt.addPoint(811,77); bassgt.addPoint(824,66); bassgt.addPoint(825,61); bassgt.addPoint(842,53); bassgt.addPoint(852,43); bassgt.addPoint(853,29); bassgt.addPoint(870,20); g2.setColor(Color.black); g2.fill(bassgt); g2.draw(bassgt); Polygon bassgt2 = new Polygon(); bassgt2.addPoint(845,78); bassgt2.addPoint(845,98); bassgt2.addPoint(843,98); bassgt2.addPoint(842,105); bassgt2.addPoint(839,109); bassgt2.addPoint(834,103); bassgt2.addPoint(832,85); bassgt2.addPoint(845,78); g2.setColor(Color.white); g2.fill(bassgt2); g2.draw(bassgt2); Polygon drums = new Polygon (); drums.addPoint(713,104); drums.addPoint(706,121); drums.addPoint(721,377); drums.addPoint(248,380); drums.addPoint(253,228); drums.addPoint(250,206); drums.addPoint(237,178); drums.addPoint(206,166); drums.addPoint(201,154); drums.addPoint(198,152); drums.addPoint(208,148); drums.addPoint(236,150); drums.addPoint(247,130); drums.addPoint(227,119); drums.addPoint(219,105); drums.addPoint(222,96); drums.addPoint(233,88); drums.addPoint(251,84); drums.addPoint(272,83); drums.addPoint(300,91); drums.addPoint(285,72); drums.addPoint(294,57); drums.addPoint(319,46); drums.addPoint(372,45); drums.addPoint(406,50); drums.addPoint(428,65); drums.addPoint(433,74); drums.addPoint(450,58); drums.addPoint(478,48); drums.addPoint(514,48); drums.addPoint(544,51); drums.addPoint(566,52); drums.addPoint(577,67); drums.addPoint(575,79); drums.addPoint(561,95); drums.addPoint(545,98); drums.addPoint(525,105); drums.addPoint(524,147); drums.addPoint(524,183); drums.addPoint(645,175); drums.addPoint(662,143); drums.addPoint(617,152); drums.addPoint(608,148); drums.addPoint(614,139); drums.addPoint(633,128); drums.addPoint(661,116); drums.addPoint(659,107); drums.addPoint(625,114); drums.addPoint(592,113); drums.addPoint(571,111); drums.addPoint(565,102); drums.addPoint(576,86); drums.addPoint(616,70); drums.addPoint(647,66); drums.addPoint(679,67); drums.addPoint(695,72); drums.addPoint(699,90); drums.addPoint(678,100); drums.addPoint(667,103); drums.addPoint(672,113); drums.addPoint(689,105); drums.addPoint(709,106); g2.setColor(Color.black); g2.fill(drums); g2.draw(drums); } } The second class: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Rectangle; import java.awt.geom.Ellipse2D; import java.awt.geom.Line2D; import javax.swing.JComponent; import java.awt.GradientPaint; /* component that draws the concert background */ public class Concertbackground extends JComponent { public void paintComponent(Graphics g) { super.paintComponent(g); // Recover Graphics2D Graphics2D g2 = (Graphics2D) g; //Background Top g2.setColor(Color.BLUE); Rectangle backgroundTop = new Rectangle (0, 0, getWidth(), getHeight() / 4); g2.fill(backgroundTop); // Background bottom g2.setColor(Color.GREEN); Rectangle backgroundBottom = new Rectangle (0, getHeight() / 2, getWidth(), getHeight() / 2); g2.fill(backgroundBottom); // Speaker base g2.setColor(Color.BLACK); Rectangle base = new Rectangle (0, 0, 50, 100); g2.fill(base); // Speakers circles gray top g2.setColor(Color.DARK_GRAY); Ellipse2D.Double speakerTop = new Ellipse2D.Double(10, 10, 30, 30); g2.fill(speakerTop); //speakers circles black top g2.setColor(Color.BLACK); Ellipse2D.Double speakerTop1 = new Ellipse2D.Double(15, 15, 20, 20); g2.fill(speakerTop1); // Speakers circles gray bottom g2.setColor(Color.DARK_GRAY); Ellipse2D.Double speakerBottom = new Ellipse2D.Double(10, 50, 30, 30); g2.fill(speakerBottom); //speakers circles black bottom g2.setColor(Color.BLACK); Ellipse2D.Double speakerBottom1 = new Ellipse2D.Double(15, 55, 20, 20); g2.fill(speakerBottom1); } } My main question is how do I change my Jframe so it can use as many classes as I want, It cant be the size of my classes because they were used with the same 1000, 800 Jframe to make the classes. I also need to be able to add more than just these two classes to my Jframe.

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  • Rails, Capistrano, Nginx, Unicorn - Application has been already initialized (RuntimeError)

    - by Andy Copley
    Can anyone shed some light on what exactly this error refers to? I'm having trouble deploying new versions of the site. I, INFO -- : reloading config_file=[snip]/current/config/unicorn.rb I, INFO -- : Refreshing Gem list E, ERROR -- : error reloading config_file=[snip]/current/config/unicorn.rb: Application has been already initialized. (RuntimeError) E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/application.rb:135:in `initialize!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/railties-3.2.3/lib/rails/railtie/configurable.rb:30:in `method_missing' E, ERROR -- : [snip]/releases/20120907085937/config/environment.rb:5:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `block in require' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:236:in `load_dependency' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:251:in `require' E, ERROR -- : config.ru:4:in `block in <main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize' E, ERROR -- : config.ru:1:in `new' E, ERROR -- : config.ru:1:in `<main>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `eval' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn.rb:44:in `block in builder' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `call' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:696:in `build_app!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:677:in `load_config!' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/lib/unicorn/http_server.rb:303:in `join' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/gems/unicorn-4.3.1/bin/unicorn:121:in `<top (required)>' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `load' E, ERROR -- : [snip]/shared/bundle/ruby/1.9.1/bin/unicorn:23:in `<main>' I, INFO -- : reaped #<Process::Status: pid 3182 exit 0> worker=0 I, INFO -- : reaped #<Process::Status: pid 3185 exit 0> worker=1 I, INFO -- : reaped #<Process::Status: pid 3188 exit 0> worker=2 I, INFO -- : reaped #<Process::Status: pid 3191 exit 0> worker=3 I, INFO -- : worker=0 ready I, INFO -- : worker=3 ready I, INFO -- : worker=1 ready I, INFO -- : worker=2 ready Unicorn.rb root = "/home/[user]/apps/[site]/current" working_directory root pid "#{root}/tmp/pids/unicorn.pid" stderr_path "#{root}/log/unicorn.log" stdout_path "#{root}/log/unicorn.log" listen "/tmp/unicorn.[site].sock", :backlog => 2048 worker_processes 4 preload_app true timeout 30 before_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.connection.disconnect! end after_fork do |server, worker| defined?(ActiveRecord::Base) and ActiveRecord::Base.establish_connection end Any help appreciated - I can pull more config files if required.

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  • Crash in audio resampler with some audio rates - FFMPEG PHP ( Solved! )

    - by Olaf Erlandsen
    i have a problem with this command( FFMPEG PHP ): Command: ffmpeg -i 62f76f050494f0ed6a5997967c00c0c0.wmv -ss 0 -t 99 -y -ar 44100 -async 44100 -r 29.970 -ac 2 -qscale 5 -f flv 62f76f050494f0ed6a5997967c00c0c0.flv Output: FFmpeg version 0.6.5, Copyright (c) 2000-2010 the FFmpeg developers built on Jan 29 2012 17:52:15 with gcc 4.4.5 20110214 (Red Hat 4.4.5-6) configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 --mandir=/usr/share/man --incdir=/usr/include --disable-avisynth --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC' --enable-avfilter --enable-avfilter-lavf --enable-libdc1394 --enable-libdirac --enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libgsm --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libx264 --enable-gpl --enable-nonfree --enable-postproc --enable-pthreads --enable-shared --enable-swscale --enable-vdpau --enable-version3 --enable-x11grab libavutil 50.15. 1 / 50.15. 1 libavcodec 52.72. 2 / 52.72. 2 libavformat 52.64. 2 / 52.64. 2 libavdevice 52. 2. 0 / 52. 2. 0 libavfilter 1.19. 0 / 1.19. 0 libswscale 0.11. 0 / 0.11. 0 libpostproc 51. 2. 0 / 51. 2. 0 [asf @ 0xe81670]max_analyze_duration reached Input #0, asf, from '/var/www/resources/tmp/62f76f050494f0ed6a5997967c00c0c0.wmv': Metadata: WMFSDKVersion : 12.0.7601.17514 WMFSDKNeeded : 0.0.0.0000 IsVBR : 0 Duration: 00:00:50.87, bitrate: 2467 kb/s Stream #0.0: Audio: wmapro, 44100 Hz, stereo, flt, 256 kb/s Stream #0.1: Video: vc1, yuv420p, 950x460 [PAR 1:1 DAR 95:46], 25 fps, 25 tbr, 1k tbn, 25 tbc Output #0, flv, to '/var/www/resources/media/62f76f050494f0ed6a5997967c00c0c0.flv': Metadata: encoder : Lavf52.64.2 Stream #0.0: Video: flv, yuv420p, 950x460 [PAR 1:1 DAR 95:46], q=2-31, 200 kb/s, 1k tbn, 29.97 tbc Stream #0.1: Audio: libmp3lame, 11025 Hz, stereo, s16, 64 kb/s Stream mapping: Stream #0.1 -> #0.0 Stream #0.0 -> #0.1 Press [q] to stop encoding frame= 72 fps= 0 q=5.0 size= 0kB time=10.91 bitrate= 0.0kbits/s Multiple frames in a packet from stream 0 Warning, using s16 intermediate sample format for resampling frame= 141 fps=139 q=5.0 size= 103kB time=8.15 bitrate= 103.2kbits/s frame= 220 fps=144 q=5.0 size= 875kB time=10.92 bitrate= 656.6kbits/s frame= 290 fps=143 q=5.0 size= 1525kB time=13.74 bitrate= 909.1kbits/s frame= 356 fps=141 q=5.0 size= 2153kB time=15.99 bitrate=1103.1kbits/s frame= 427 fps=141 q=5.0 size= 2847kB time=18.70 bitrate=1247.0kbits/s frame= 497 fps=141 q=5.0 size= 3771kB time=21.16 bitrate=1460.0kbits/s frame= 575 fps=142 q=5.0 size= 4695kB time=24.61 bitrate=1563.0kbits/s frame= 639 fps=141 q=5.0 size= 5301kB time=26.80 bitrate=1620.2kbits/s frame= 703 fps=139 q=5.0 size= 5829kB time=29.36 bitrate=1626.2kbits/s frame= 774 fps=139 q=5.0 size= 6659kB time=32.39 bitrate=1684.0kbits/s frame= 842 fps=139 q=5.0 size= 7915kB time=35.27 bitrate=1838.6kbits/s frame= 911 fps=139 q=5.0 size= 9011kB time=37.98 bitrate=1943.4kbits/s frame= 975 fps=138 q=5.0 size= 9788kB time=40.59 bitrate=1975.3kbits/s frame= 1041 fps=138 q=5.0 size= 10904kB time=43.83 bitrate=2037.9kbits/s frame= 1115 fps=138 q=5.0 size= 11795kB time=46.24 bitrate=2089.8kbits/s frame= 1183 fps=138 q=5.0 size= 12678kB time=48.74 bitrate=2130.7kbits/s frame= 1247 fps=137 q=5.0 size= 13964kB time=51.36 bitrate=2227.5kbits/s frame= 1271 fps=136 q=5.0 Lsize= 15865kB time=58.86 bitrate=2208.1kbits/s video:15366kB audio:462kB global headers:0kB muxing overhead 0.238956% Problem: Warning, using s16 intermediate sample format for resampling I've also tried changing the parameter From -ar 44100 to -ar 11025 Thanks! Solution: Read this link: http://en.wikipedia.org/wiki/MP3#Bit_rate

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  • Cisco VPNClient from Mac won't connect using iPhone Tethering

    - by Dan Short
    I just set up iPhone tethering from my Snow Leopard Macbook Pro to my iPhone 3GS with the Datapro 4GB plan from AT&T. When attempting to connect to my corporate VPN from the MacBook Pro with Cisco VPNClient 4.9.01 (0100) I get the following log information: Cisco Systems VPN Client Version 4.9.01 (0100) Copyright (C) 1998-2006 Cisco Systems, Inc. All Rights Reserved. Client Type(s): Mac OS X Running on: Darwin 10.6.0 Darwin Kernel Version 10.6.0: Wed Nov 10 18:13:17 PST 2010; root:xnu-1504.9.26~3/RELEASE_I386 i386 Config file directory: /etc/opt/cisco-vpnclient 1 13:02:50.791 02/22/2011 Sev=Info/4 CM/0x43100002 Begin connection process 2 13:02:50.791 02/22/2011 Sev=Warning/2 CVPND/0x83400011 Error -28 sending packet. Dst Addr: 0x0AD337FF, Src Addr: 0x0AD33702 (DRVIFACE:1158). 3 13:02:50.791 02/22/2011 Sev=Warning/2 CVPND/0x83400011 Error -28 sending packet. Dst Addr: 0x0A2581FF, Src Addr: 0x0A258102 (DRVIFACE:1158). 4 13:02:50.792 02/22/2011 Sev=Info/4 CM/0x43100004 Establish secure connection using Ethernet 5 13:02:50.792 02/22/2011 Sev=Info/4 CM/0x43100024 Attempt connection with server "209.235.253.115" 6 13:02:50.792 02/22/2011 Sev=Info/4 CVPND/0x43400019 Privilege Separation: binding to port: (500). 7 13:02:50.793 02/22/2011 Sev=Info/4 CVPND/0x43400019 Privilege Separation: binding to port: (4500). 8 13:02:50.793 02/22/2011 Sev=Info/6 IKE/0x4300003B Attempting to establish a connection with 209.235.253.115. 9 13:02:51.293 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 10 13:02:51.894 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 11 13:02:52.495 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 12 13:02:53.096 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 13 13:02:53.698 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 14 13:02:54.299 02/22/2011 Sev=Warning/2 CVPND/0x83400018 Output size mismatch. Actual: 0, Expected: 237. (DRVIFACE:1319) 15 13:02:54.299 02/22/2011 Sev=Info/4 IKE/0x43000075 Unable to acquire local IP address after 5 attempts (over 5 seconds), probably due to network socket failure. 16 13:02:54.299 02/22/2011 Sev=Warning/2 IKE/0xC300009A Failed to set up connection data 17 13:02:54.299 02/22/2011 Sev=Info/4 CM/0x4310001C Unable to contact server "209.235.253.115" 18 13:02:54.299 02/22/2011 Sev=Info/5 CM/0x43100025 Initializing CVPNDrv 19 13:02:54.300 02/22/2011 Sev=Info/4 CVPND/0x4340001F Privilege Separation: restoring MTU on primary interface. 20 13:02:54.300 02/22/2011 Sev=Info/4 IKE/0x43000001 IKE received signal to terminate VPN connection 21 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x43700008 IPSec driver successfully started 22 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x43700014 Deleted all keys 23 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x4370000D Key(s) deleted by Interface (192.168.0.171) 24 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x43700014 Deleted all keys 25 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x43700014 Deleted all keys 26 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x43700014 Deleted all keys 27 13:02:54.300 02/22/2011 Sev=Info/4 IPSEC/0x4370000A IPSec driver successfully stopped The key line is 15: 15 13:02:54.299 02/22/2011 Sev=Info/4 IKE/0x43000075 Unable to acquire local IP address after 5 attempts (over 5 seconds), probably due to network socket failure. I can't find anything online about this. I found a single entry for the error message in Google, and it was a swedish (or some other nordic language site) that didn't have an answer to the question. I've tried connecting through both USB and Bluetooth tethering to the iPhone, and they both return the exact same results. I don't have direct control over the firewall, but if changes are necessary to make it work, I may be able to get the powers-that-be to make adjustments. A solution that doesn't require reconfiguring the firewall would be far better of course... Does anyone know what I can do to make this behave? Thanks, Dan

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  • http request via iptables --to-destination ip redirect results in no response

    - by Wouter Vegter
    I have two Ubuntu servers with each having their own ip addresses. Let's call them server1 and server2, having respectively ip 1.1.1.1 and 2.2.2.2 I have a nginx running on server2. The sole purpose I want server1 to have is to redirect all incoming http (so port 80) requests to server2 without clients noticing that their request is being redirected. I tried the following command on server1: iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 2.2.2.2 But when I enter 1.1.1.1 in my browser I get no respond: the page keeps trying to load without giving any message or error message (I get a time-out after 2-3 mins). But when I do remove the above iptables rule I immediately do get a "page not found error" when I enter 1.1.1.1 in my browser; so something is working but not as it should: when I enter 1.1.1.1 I want the html page to load that is hosted on 2.2.2.2 Because when i enter 2.2.2.2 in my browser I do see the webpage loaded. Could anyone please help me with this? I am searching quite some time (on severfault & Google) on this now so that's why I ask. Many thanks for reading my question! Update: Thank you all for you information. Unfortunately I still get no response I have the following iptables configuration: root@ip-10-48-238-216:/home/ubuntu# sudo iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination root@ip-10-48-238-216:/home/ubuntu# sudo iptables -t nat -L Chain PREROUTING (policy ACCEPT) target prot opt source destination DNAT tcp -- anywhere anywhere tcp dpt:www to:2.2.2.2 Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain POSTROUTING (policy ACCEPT) target prot opt source destination When i run tcpdump and do request via chrome to 1.1.1.1 i get the following root@ip-10-48-238-216:/home/ubuntu# sudo tcpdump -i eth0 port 80 -vv tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes 13:56:18.346625 IP (tos 0x0, ttl 52, id 12055, offset 0, flags [DF], proto TCP (6), length 60) 212-123-161-112.ip.telfort.nl.16386 ip-10-48-238-216.eu-west-1.compute.internal.www: Flags [S], cksum 0xb398 (correct), seq 2639758575, win 5840, options [mss 1460,sackOK,TS val 1223672 ecr 0,nop,wscale 6], length 0 13:56:18.346662 IP (tos 0x0, ttl 51, id 12055, offset 0, flags [DF], proto TCP (6), length 60) 212-123-161-112.ip.telfort.nl.16386 ww1dc1.shopreme.com.www: Flags [S], cksum 0x9ee0 (correct), seq 2639758575, win 5840, options [mss 1460,sackOK,TS val 1223672 ecr 0,nop,wscale 6], length 0 13:56:18.598747 IP (tos 0x0, ttl 52, id 10138, offset 0, flags [DF], proto TCP (6), length 60) 212-123-161-112.ip.telfort.nl.16387 ip-10-48-238-216.eu-west-1.compute.internal.www: Flags [S], cksum 0xac40 (correct), seq 2645658541, win 5840, options [mss 1460,sackOK,TS val 1223735 ecr 0,nop,wscale 6], length 0 13:56:18.598777 IP (tos 0x0, ttl 51, id 10138, offset 0, flags [DF], proto TCP (6), length 60) 212-123-161-112.ip.telfort.nl.16387 ww1dc1.shopreme.com.www: Flags [S], cksum 0x9788 (correct), seq 2645658541, win 5840, options [mss 1460,sackOK,TS val 1223735 ecr 0,nop,wscale 6], length 0 ^C 4 packets captured 4 packets received by filter 0 packets dropped by kernel the mentioned address relate to the following 212-123-161-112.ip.telfort.nl.16386 : my personal computer ww1dc1.shopreme.com.www : dns of server2 (2.2.2.2) ip-10-48-238-216.eu-west-1.compute.internal.www : amazon web services ec2 internal address of server1 (1.1.1.1) However, the tcpdump log on server2 (2.2.2.2) stays empty and I get no response back in my browser. I am able to ping from server1 to server2. And net.ipv4.ip_forward is set to 1 and so is /proc/sys/net/ipv4/ip_forward Could there be anything else that is missing?

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