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Articles indexed Wednesday April 14 2010

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  • Is the Cloud ready for an Enterprise Java web application? Seeking a JEE hosting advice.

    - by Jakub Holý
    Greetings to all the smart people around here! I'd like to ask whether it is feasible or a good idea at all to deploy a Java enterprise web application to a Cloud such as Amazon EC2. More exactly, I'm looking for infrastructure options for an application that shall handle few hundred users with long but neither CPU nor memory intensive sessions. I'm considering dedicated servers, virtual private servers (VPSs) and EC2. I've noticed that there is a project called JBoss Cloud so people are working on enabling such a deployment, on the other hand it doesn't seem to be mature yet and I'm not sure that the cloud is ready for this kind of applications, which differs from the typical cloud-based applications like Twitter. Would you recommend to deploy it to the cloud? What are the pros and cons? The application is a Java EE 5 web application whose main function is to enable users to compose their own customized Product by combining the available Parts. It uses stateless and stateful session beans and JPA for persistence of entities to a RDBMS and fetches information about Parts from the company's inventory system via a web service. Aside of external users it's used also by few internal ones, who are authenticated against the company's LDAP. The application should handle around 300-400 concurrent users building their product and should be reasonably scalable and available though these qualities are only of a medium importance at this stage. I've proposed an architecture consisting of a firewall (FW) and load balancer supporting sticky sessions and https (in the Cloud this would be replaced with EC2's Elastic Load Balancing service and FW on the app. servers, in a physical architecture the load-balancer would be a HW), then two physical clustered application servers combined with web servers (so that if one fails, a user doesn't loose his/her long built product) and finally a database server. The DB server would need a slave backup instance that can replace the master instance if it fails. This should provide reasonable availability and fault tolerance and provide good scalability as long as a single RDBMS can keep with the load, which should be OK for quite a while because most of the operations are done in the memory using a stateful bean and only occasionally stored or retrieved from the DB and the amount of data is low too. A problematic part could be the dependency on the remote inventory system webservice but with good caching of its outputs in the application it should be OK too. Unfortunately I've only vague idea of the system resources (memory size, number and speed of CPUs/cores) that such an "average Java EE application" for few hundred users needs. My rough and mostly unfounded estimate based on actual Amazon offerings is that 1.7GB and a single, 2-core "modern CPU" with speed around 2.5GHz (the High-CPU Medium Instance) should be sufficient for any of the two application servers (since we can handle higher load by provisioning more of them). Alternatively I would consider using the Large instance (64b, 7.5GB RAM, 2 cores at 1GHz) So my question is whether such a deployment to the cloud is technically and financially feasible or whether dedicated/VPS servers would be a better option and whether there are some real-world experiences with something similar. Thank you very much! /Jakub Holy PS: I've found the JBoss EAP in a Cloud Case Study that shows that it is possible to deploy a real-world Java EE application to the EC2 cloud but unfortunately there're no details regarding topology, instance types, or anything :-(

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  • How Does Microsoft Office 2010 Compare?

    The release of the new Microsoft Office suite isn';t the most exciting thing in the world, the fact that it is used nearly every day on my work computer doesn';t help matters. Nevertheless, I thought i... [Author: Chris Holgate - Computers and Internet - April 14, 2010]

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  • When Using Social Networking Sites Exercise Caution

    With more people using social networking sites there is also an increase in the various threats people may encounter online. Unfortunately population masses tend to attract people with less than nobl... [Author: TJ Philpott - Computers and Internet - April 14, 2010]

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  • can't add a custom marker to Google maps ( JS )

    - by user296516
    Hi, Was wondering, how do I add a custom marker to google maps, JavaScript, integrated into my site. This code adds a regular marker: var marker = new GMarker(center); map.addOverlay(marker); but where do I insert an image tag (say, "marker.png" ) for it to appear instead of the regular google marker? Thanks!

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  • is there a 'git find'?

    - by Martin DeMello
    Is there a git find analogue of git grep, i.e., something that will find a filename by pattern in the tree? I've gone through a lot of git documentation and not found this, but I'm having a hard time believing it doesn't exist somewhere.

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  • Trouble compiling C/C++ project in NetBeans 6.8 with MinGW on Windows

    - by dontoo
    I am learning C and because VC++ 2008 doesn't support C99 features I have just installed NetBeans and configure it to work with MinGW. I can compile single file project ( main.c) and use debugger but when I add new file to project I get error "undefined reference to ... function(code) in that file..". Obviously MinGW does't link my files or I don't know how properly add them to my project (c standard library files work fine). /bin/make -f nbproject/Makefile-Debug.mk SUBPROJECTS= .build-conf make[1]: Entering directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' /bin/make -f nbproject/Makefile-Debug.mk dist/Debug/MinGW-Windows/cppapplication_7.exe make[2]: Entering directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' mkdir -p dist/Debug/MinGW-Windows gcc.exe -o dist/Debug/MinGW-Windows/cppapplication_7 build/Debug/MinGW-Windows/main.o build/Debug/MinGW-Windows/main.o: In function `main': C:/Users/don/Documents/NetBeansProjects/CppApplication_7/main.c:5: undefined reference to `X' collect2: ld returned 1 exit status make[2]: *** [dist/Debug/MinGW-Windows/cppapplication_7.exe] Error 1 make[2]: Leaving directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' make[1]: *** [.build-conf] Error 2 make[1]: Leaving directory `/c/Users/don/Documents/NetBeansProjects/CppApplication_7' make: *** [.build-impl] Error 2 BUILD FAILED (exit value 2, total time: 1s) main.c #include "header.h" int main(int argc, char** argv) { X(); return (EXIT_SUCCESS); } header.h #ifndef _HEADER_H #define _HEADER_H #include <stdio.h> #include <stdlib.h> void X(void); #endif source.c #include "header.h" void X(void) { printf("dsfdas"); }

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  • After travelling back in Firefox history, javascript won't run.

    - by Patonza
    When I use the back button on Firefox to reach a previously visited page, scripts on that page won't run again. Is there any fix/workaround to have the scripts execute again when viewing the page the second time? Please note that I have tested the same pages on Google Chrome and Internet Explorer and they work as intended. Here are the files and the steps I used to test the problem: (navigate to 0.html, click to get to 1.html, back button) 0.html <html><body> <script type="text/javascript"> window.onload = function() { alert('window.onload alert'); }; alert('inline alert'); </script> <a href="1.html">Click Me!</a> </body></html> 1.html <html><body> <p>Go BACK!</p> </body></html>

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  • Jquery Event onChange for Div

    - by David
    I have a page with the following two divs: <div id="searchResults"> </div> <div class="postSearchOptions" style="display: none;"> </div> Is there any way that I can make the "postSearchOptions" div appear when the "searchResults" div is updated by an AJAX call? I don't control the AJAX calls and I want to detect any change in the "searchResults" div. I tried writing the following JQuery code, but then realized that it requires Jquery 1.4 and I only have 1.3: $("#searchResults").live("change", function() { $(".postSearchOptions").css("display", "inline"); }); Is there any way to catch the event of the searchResults div changing using either standard JavaScript or Jquery 1.3? Thanks!

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  • Indexing large DB's with Lucene/PHP

    - by thebluefox
    Afternoon chaps, Trying to index a 1.7million row table with the Zend port of Lucene. On small tests of a few thousand rows its worked perfectly, but as soon as I try and up the rows to a few tens of thousands, it times out. Obviously, I could increase the time php allows the script to run, but seeing as 360 seconds gets me ~10,000 rows, I'd hate to think how many seconds it'd take to do 1.7million. I've also tried making the script run a few thousand, refresh, and then run the next few thousand, but doing this clears the index each time. Any ideas guys? Thanks :)

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  • Ways to save enums in database

    - by corgrath
    Hey guys. I am wondering what the best ways to save enums into a database is. I know there are name() and valueOf() methods to make it into a String back. But are there any other (flexible) options to store these values? Is there a smart way to make them into unique numbers (ordinal() is not safe to use)? Any comments and suggestions would be helpful :) Update: Thanks for all awesome and fast answers! It was as I suspected. However a note to 'toolkit'; That is one way. The problem is that I would have to add the same methods with each enum type i create. Thats a lot of duplicated code and, at the moment, Java does not support any solutions to this (You cannot let enum extend other classes). However, thanks for all answers!

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  • Is the REST support in Spring 3's MVC Framework production quality yet?

    - by glenjohnson
    Hi all, Since Spring 3 was released in December last year, I have been trying out the new REST features in the MVC framework for a small commercial project involving implementing a few RESTful Web Services which consume XML and return XML views using JiBX. I plan to use either Hibernate or JDBC Templates for the data persistence. As a Spring 2.0 developer, I have found Spring 3's (and 2.5's) new annotations way of doing things quite a paradigm shift and have personally found some of the new MVC annotation features difficult to get up to speed with for non-trivial applications - as such, I am often having to dig for information in forums and blogs that is not apparent from going through the reference guide or from the various Spring 3 REST examples on the web. For deadline-driven production quality and mission critical applications implementing a RESTful architecture, should I be holding off from Spring 3 and rather be using mature JSR 311 (JAX-RS) compliant frameworks like RESTlet or Jersey for the REST layer of my code (together with Spring 2 / 2.5 to tie things together)? I had no problems using RESTlet 1.x in a previous project and it was quite easy to get up to speed with (no magic tricks behind the scenes), but when starting my current project it initially looked like the new REST stuff in Spring 3's MVC Framework would make life easier. Do any of you out there have any advice to give on this? Does anyone know of any commercial / production-quality projects using, or having successfully delivered with, the new REST stuff in Spring 3's MVC Framework. Many thanks Glen

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  • Google Maps API not working (help!)

    - by janoChen
    When I click to the embedded Google Maps API of the following Web Page: http://ada.kiexpro.com/html/list.html (click ?? at the top-right corner). It displays: This web site needs a different Google Map API key. A new key can be generted at http://code.google.com/apis/maps/. Sorry but I've never used this application before. Do I have to just generate a new code in order to solve the problem? Or there are another problems?

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  • NSString potential leak

    - by VansFannel
    Hello. When I build and analyze my project on XCode, I obtain a 'warning' on the following line: NSString *contactEmail = (NSString *)ABMultiValueCopyValueAtIndex(emailInfo, 0); The message is: Potential leak on object allocated on line ... and stored into contactEmail. Is there any error on that line? UPDATE I get the same 'warning' with this line of code: ABMultiValueRef emailInfo = ABRecordCopyValue(person, kABPersonEmailProperty); But here, I can't do this: [emailInfo release]; I'm developing for iPhone.

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  • php: geting ip addres

    - by Syom
    i want to get an ip addres of visitors. could you tell me what element of $_SERVER[] i should use? $_SERVER['HTTP_CLIENT_IP']; $_SERVER['HTTP_X_FORWARDED_FOR']; or $_SERVER['REMOTE_ADDR']; thanks

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  • Ruby Methods: return an usage string when insufficient arguments are given

    - by Shyam
    Hi, After creating a serious bunch of classes, with initialize methods, loading them in IRb requires to look back at the code. However, I think it should be easy enough to return a usage message, instead of: ArgumentError: wrong number of arguments (0 for 9) So I prefer to return a string with the human readable arguments, by example using "puts" or just a return of a string. Now I have seen the rescue keyword inside begin-end code, but I wonder how I could catch the ArgumentError when the initialize method is called. Thank you for your answers, feedback and comments!

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  • Store an image in a SQL Server CE database

    - by Vaccano
    Does any one know of an example on how to store an image in a SQL Server CE database? What data type should the column be? (I am guessing binary.) I use Linq-To-Datasets. Is it possible using that to put the image into the database and pull it out again later? Thanks for any advice.

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  • Console.Write Not Working In Win Forms App

    - by Steven
    I created a VB.NET Windows Forms Application in Visual Studio 2008. When I run my program from the command-line, I get no output (only the next prompt). What am I doing wrong? Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Debug.Write("Foo") Debug.Flush() Console.WriteLine("foo") Console.Beep(800, 100) 'confirm this function is called' Me.Close() End Sub EDIT: Can a program have a form and a console? EDIT2: Ho's answer works. However, the output appears on the next command-line prompt. Can a Winforms application tell the command-line to wait until it's finished instead of immediately returning?

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  • How do I Emit Escaped XML representation of a Node in my XSLT's HTML Output

    - by Emmanuel
    I'm transforming XML to an HTML document. In this document I want to embed XML markup for a node that was just transformed (the HTML document is a technical spec). For example, if my XML was this: <transform-me> <node id="1"> <stuff type="floatsam"> <details>Various bits</details> </stuff> </node> </transform-me> I'd want my XSLT output to look something like this: <h1>Node 1</h1> <h2>Stuff (floatsam)</h2> Various bits <h2>The XML</h2> &lt;stuff type=&quot;floatsam&quot;&gt; &lt;details&gt;Various bits&lt;/details&gt; &lt;/stuff&gt; I'm hoping there is an XSLT function that I can call in my <stuff> template to which I can pass the current node (.) and get back escaped XML markup for <stuff> and all its descendants. I have a feeling unparsed-text() might be the way to go but can't get it to work.

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  • What type of objects can be sent back to an action Method using HTML.HIDDEN()

    - by Richard77
    Hello, 1)Let's say I've this form: <%Using(Html.BeginForm()){%> <% = Html.Hidden("myObject", (cast to the appropriate type)ViewData["KeyForMyObject"]%> <input type = "submit" "Submit Object"> <%}%> 2) Here's the Action which's supposed to intercept the value of the object public ActionResult MyAction(Type myObject) { //Do Something with the object } Here's my question: What type of objects the Hidden field can support? In fact, when ViewData["KeyForMyObject"] contains a string, int, or bool, myAction is able to retrieve the value. But, when it comes to objects, such as List, and dictionary, nothing happens. When I debug to check the local values, I see null for Type myObject in the MyMethod. So what are the rules in MVC when it comes to a List or Dictionary? ================================= EDIT To make things simpler, can I write something like this <% = Html.Hidden("contactDic", (Dictionary<string, string>) ViewData["contacts"])%> and expect to retrieve the dictionary in the action Method like this public ActionResult myMethod(Dictionary<string, string> contactDic) { //Do something with the dictionary } Thanks for Helping

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