Search Results

Search found 47896 results on 1916 pages for 'google go'.

Page 341/1916 | < Previous Page | 337 338 339 340 341 342 343 344 345 346 347 348  | Next Page >

  • SEO and Ad Networks Go Hand in Hand - How?

    Managing the presence of companies on the web is a challenging task. It is important to make use of experts who have hands on experience in the field of web marketing. You can't build a successful business with out employing wise strategies.

    Read the article

  • Should I go with Android or Try Windows Phone 7?

    - by Omnion
    I already know C# and am familiar with XNA. So it would make sense to develop for the Windows Phone 7, but would it be worth while to learn Java, get familiar with Android, and instead develop for Android devices? Android has been around longer so it would probably have a larger user base. Is it really worth it to try to develop for one of the more popular mobile platforms. (Windows Phone 7 has been out for like a month?) I haven't tried either one yet though. I'm also going to buy a phone, so this decision would probably influence the phone that I buy. (to develop/test on)

    Read the article

  • Which is a better design pattern for a database wrapper: Save as you go or Save when your done?

    - by izuriel
    I know this is probably a bad way to ask this question. I was unable to find another question that addressed this. The full question is this: We're producing a wrapper for a database and have two different viewpoints on managing data with the wrapper. The first is that all changes made to a data object in code must be persisted in the database by calling a "save" method to actually save the changes. The other side is that these changes should be save as they are made, so if I change a property it's saved, I change another it's save as well. What are the pros/cons of either choice and which is the "proper" way to manage the data?

    Read the article

  • If you had to go back and re-learn your skill set, how would you do it?

    - by vorbb
    My younger brother is looking to start programming. He's 14, and technically-inclined, but no real experience programming. He's looking to me for guidance, and I don't feel as if my experience is enough, so I figured I'd ask here. He's more interested in web programming, but also has an interest in desktop/mobile/server applications. What would be a good learning path for him to take? I'm going to buy him a bunch of books for Christmas to get him started; the question is, what should he learn, and in which order? The way I see it, he needs to learn theory and code. I'd like to start him off with Python or Ruby or PHP. If he wants to get in to web, he's also going to need to learn HTML, CSS, Javascript, etc. Out of those three domains (Languages, Theory, Markup/Etc.), what is the best order do you think to learn in? Also, am I missing anything? Thanks!

    Read the article

  • How many LOC/day "top" (google, MS, FB) engeneers produce? [closed]

    - by NoSenseEtAl
    I know that 25 lines of lock free code is harder to do than 1000 lines of On_Click()... code but I wonder does anybody know in general what is the productivity of the average programmer in top tech companies. Motivation: I often go ??? mode when I see how low LoC/ day i produce(Im new to the my current language and Im part of the big project, but still..) and I would like to know how bad I am. :) If you are gonna warn me that LoC is a terrible measure I agree, but it is most exact one in a sense that I cant go and write 0.01% of Chrome or IE and say it took me this long so....

    Read the article

  • Disk drive won't let go of password prompt at bootup?

    - by user54003
    I had a hacker intrude into my system, at the time it was obvious, so I reinstalled. However, I am left with what appears to be a fatal problem as far as one of my disk drives goes. When I install that drive in my system, a prompt comes up for the disk password, and what it is asking for is a root password. The disk works otherwise normally but despite all my efforts, I have not been able to fix this disk. I have gotten the operating system parted magic and done the most extreme clean up available, the internal one which sends a signal to the disk electronics which runs a built in clean up program. Darik's boot and nuke, I've tried them all but I can't seem to remove this with anything in the Linux line. Does anyone have any suggestions? I've run gparted, created a Sun, an Apple and various other schemes to partition the disk, all to no avail. Can anyone help?

    Read the article

  • How would I go about updating my electronic circuit simulator's 'electricity'?

    - by liqwidice
    I have made an application which allows the user to place down wires, power sources, and inverters on a virtual circuit board. All connections between tiles are automatic, as shown here: As you can see in the last image, the updating of power throughout this grid is not yet functioning. I think I understand how to do this updating conceptually, but getting it to work in my program is appearing to be much more difficult than I first imagined. My source code can be found here. If you have any tips as to how to I might approach this monstrous task, please let me know. EDIT The goal here is to simply get a working application. Getting tiles to pass on power to their neighbors is quite easy, but the tricky part is getting wires to "unpower" after the removal of a power source. The size of the grid is just 18x18, so efficiency really isn't a factor, for those wondering.

    Read the article

  • Spring Security - Persistent Remember Me Issue

    - by Taylor L
    I've been trying to track down why Spring Security isn't creating the Spring Security remember me cookie (SPRING_SECURITY_REMEMBER_ME_COOKIE). At first glance, the logs make it seem like the login is failing, but the login is actually successful in the sense that if I navigate to a page that requires authentication I am not redirected back to the login page. However, the logs appear to be saying the login credentials are invalid. I'm using Spring 3.0.1, Spring Security 3.0.1, and Google App Engine 1.3.1. Any ideas as to what is going on? Mar 16, 2010 10:05:56 AM org.springframework.security.web.authentication.rememberme.PersistentTokenBasedRememberMeServices onLoginSuccess FINE: Creating new persistent login for user [email protected] Mar 16, 2010 10:10:07 AM org.springframework.security.web.authentication.rememberme.AbstractRememberMeServices loginFail FINE: Interactive login attempt was unsuccessful. Mar 16, 2010 10:10:07 AM org.springframework.security.web.authentication.rememberme.AbstractRememberMeServices cancelCookie FINE: Cancelling cookie Below is the relevant portion of the applicationContext-security.xml. <http auto-config="false"> <intercept-url pattern="/css/**" filters="none" /> <intercept-url pattern="/img/**" filters="none" /> <intercept-url pattern="/js/**" filters="none" /> <intercept-url pattern="/app/admin/**" filters="none" /> <intercept-url pattern="/app/login/**" filters="none" /> <intercept-url pattern="/app/register/**" filters="none" /> <intercept-url pattern="/app/error/**" filters="none" /> <intercept-url pattern="/" filters="none" /> <intercept-url pattern="/**" access="ROLE_USER" /> <logout logout-success-url="/" /> <form-login login-page="/app/login" default-target-url="/" authentication-failure-url="/app/login?login_error=1" /> <session-management invalid-session-url="/app/login" /> <remember-me services-ref="rememberMeServices" key="myKey" /> </http> <authentication-manager alias="authenticationManager"> <authentication-provider user-service-ref="userDetailsService"> <password-encoder hash="sha-256" base64="true"> <salt-source user-property="username" /> </password-encoder> </authentication-provider> </authentication-manager> <beans:bean id="userDetailsService" class="com.my.service.auth.UserDetailsServiceImpl" /> <beans:bean id="rememberMeServices" class="org.springframework.security.web.authentication.rememberme.PersistentTokenBasedRememberMeServices"> <beans:property name="userDetailsService" ref="userDetailsService" /> <beans:property name="tokenRepository" ref="persistentTokenRepository" /> <beans:property name="key" value="myKey" /> </beans:bean> <beans:bean id="persistentTokenRepository" class="com.my.service.auth.PersistentTokenRepositoryImpl" />

    Read the article

  • iGoogle Stack Overflow Gadget [closed]

    - by Charango
    Since SO's question database is becoming an excellent first point of call for finding answers to coding problems, some people (like me) might like to be able to fire up searches from their iGoogle home page, among the other searches you might launch from there. I've created a very simple gadget to do this, and put the source below. My hope is that this might provide a foundation on which community members with better ideas for performing this function, or ideas for enhancing it, can update it. Perhaps we could make it configurable to search via a site scope search from Google and / or a question search, for instance. I've hosted and registered this first version but if anyone makes changes and can host a new version / new pics elsewhere, please feel free. <?xml version="1.0" encoding="UTF-8"?> <Module> <ModulePrefs title="Stack Overflow Search" author="Community Wiki" author_email="[email protected]" author_affiliation="Stack Overflow" author_location="The Internet" author_aboutme="All sorts" author_link="http://stackoverflow.com" author_quote="Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law." description="Stack Overflow is rapidly becoming one of the best resources for finding answers to your programming questions. This gadget adds a question search box to your iGoogle homepage" screenshot="http://arkios-solutions.com/misc/sogadget/SOGadget.png" thumbnail="http://arkios-solutions.com/misc/sogadget/SOGadget_Thumbnail.png" singleton="true" title_url="http://stackoverflow.com" /> <Content type="html"><![CDATA[ <img src="http://i.stackoverflow.com/Content/Img/stackoverflow-logo-250.png" alt="Stackoverflow Logo"/> <div style="font-family:arial;font-size:0.8em;"> This gadget allows you to search the Stack Overflow question database. </div> <form name='SOQueryForm' action="http://stackoverflow.com/search" method="get" target="new"> <p>Your question: <input type='text' size='34' name='q' /></p> <p><input type='submit' value='Go' /></p> </form> ]]> </Content> </Module> The source / installable gadget xml are also hosted here.

    Read the article

  • iPhone SDK / Core Data usage scenario, similar to GAE data store?

    - by boliva
    Hi all, I am currently rewriting a map based App which I wrote in the past, specifically for 2.2.1 devices. Originally I wrote it to make use of SQLite databases but I would like to try and migrate it over Core Data, now that it's available on 3.X (for which I am rewriting to). I am fairly experienced in iPhone/Obj-C development, SQL and server backend technologies, but I have never had the chance to work with Core Data so IDK really if it's the appropiate tool for what I am trying to accomplish. The App works on a limited area in a map over which there are about 4000 placemarks, with different kinds of icons and sizes. Of course not all 4000 placemarks are shown at once but only those currently visible in the map viewport, and depending on the zoom level. What I am doing right now is, after the user moves the map in any way (panning or zooming) I am requesting from the backend server the required information for the placemarks that would be visible given the viewport coordinates boundaries and zoom level, however the process isn't as smooth as I'd like (the backend is sending its response in XML and I am compressing it using gzip), it takes anywhere from 1 to 3 seconds to update the display of the placemarks after the user ends moving the map. What I would like to do is to prefetch all the placemarks data at the App launch and use it all through the app life time - I don't mind storing it for later use because the data should be dynamic. The way I would do it right now is, after retrieving all the data, to store it on an SQLite db which I would query later, whenever the user moves the map, to return only the placemarks inside the viewport coordinate boundaries and specific to a given zoom level. Now, the question itself is, if is it possible to use some more 'native', object driven way to carry this queries process, which got me thinking about Core Data and if it is in any way similar to what Google App Engine offers through its datastore where you can fetch a number of objects from the backend given a certain query or criteria, without resorting to an SQL query itself. Like I said before I don't have any experience on Core Data but I have a pretty deep understanding of Obj-C and iPhone development, as well as SQL databases. Any guides on how to achieve what I'm trying (if possible at all) would be greatly appreciated.

    Read the article

  • Cross-site request forgery protections: Where do I put all these lines?

    - by brilliant
    Hello, I was looking for a python code that would be able to log in from "Google App Engine" to some of my accounts on some websites (like yahoo or eBay) and was given this code: import urllib, urllib2, cookielib url = "https://login.yahoo.com/config/login?" form_data = {'login' : 'my-login-here', 'passwd' : 'my-password-here'} jar = cookielib.CookieJar() opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar)) form_data = urllib.urlencode(form_data) # data returned from this pages contains redirection resp = opener.open(url, form_data) # yahoo redirects to http://my.yahoo.com, so lets go there instead resp = opener.open('http://mail.yahoo.com') print resp.read() Unfortunately, this code didn't work, so I asked another question here and one supporter among other things said this: "You send MD5 hash and not plain password. Also you'd have to play along with all kinds of CSRF protections etc. that they're implementing. Look: <input type="hidden" name=".tries" value="1"> <input type="hidden" name=".src" value="ym"> <input type="hidden" name=".md5" value=""> <input type="hidden" name=".hash" value=""> <input type="hidden" name=".js" value=""> <input type="hidden" name=".last" value=""> <input type="hidden" name="promo" value=""> <input type="hidden" name=".intl" value="us"> <input type="hidden" name=".bypass" value=""> <input type="hidden" name=".partner" value=""> <input type="hidden" name=".u" value="bd5tdpd5rf2pg"> <input type="hidden" name=".v" value="0"> <input type="hidden" name=".challenge" value="5qUiIPGVFzRZ2BHhvtdGXoehfiOj"> <input type="hidden" name=".yplus" value=""> <input type="hidden" name=".emailCode" value=""> <input type="hidden" name="pkg" value=""> <input type="hidden" name="stepid" value=""> <input type="hidden" name=".ev" value=""> <input type="hidden" name="hasMsgr" value="0"> <input type="hidden" name=".chkP" value="Y"> <input type="hidden" name=".done" value="http://mail.yahoo.com"> <input type="hidden" name=".pd" value="ym_ver=0&c=&ivt=&sg="> I am not quite sure where he got all these lines from and where in my code I am supposed to add them. Do You have any idea? I know I was supposed to ask him this question first, and I did, but he never returned, so I decided to ask a separate question here.

    Read the article

  • Sessions not persisting between requests

    - by klonq
    My session objects are only stored within the request scope on google app engine and I can't figure out how to persist objects between requests. The docs are next to useless on this matter and I can't find anyone who's experienced a similar problem. Please help. When I store session objects in the servlet and forward the request to a JSP using: getServletContext().getRequestDispatcher("/example.jsp").forward(request,response); Everything works like it should. But when I store objects to the session and redirect the request using: response.sendRedirect("/example/url"); The session objects are lost to the ether. In fact when I dump session key/value pairs on new requests there is absolutely nothing, session objects only appear within the request scope of servlets which create session objects. It appears to me that the objects are not being written to Memcache or Datastore. In terms of configuring sessions for my application I have set <sessions-enabled>true</sessions-enabled> In appengine-web.xml. Is there anything else I am missing? The single paragraph of documentation on sessions also notes that only objects which implement Serializable can be stored in the session between requests. I have included an example of the code which is not working below. The obvious solution is to not use redirects, and this might be ok for the example given below but some application data does need to be stored in the session between requests so I need to find a solution to this problem. EXAMPLE: The class FlashMessage gives feedback to the user from server-side operations. if (email.send()) { FlashMessage flash = new FlashMessage(FlashMessage.SUCCESS, "Your message has been sent."); session.setAttribute(FlashMessage.SESSION_KEY, flash); // The flash message will not be available in the session object in the next request response.sendRedirect(URL.HOME); } else { FlashMessage flash = new FlashMessage(FlashMessage.ERROR, FlashMessage.INVALID_FORM_DATA); session.setAttribute(FlashMessage.SESSION_KEY, flash); // The flash message is displayed without problem getServletContext().getRequestDispatcher(Templates.CONTACT_FORM).forward(request,response); } FlashMessage.java import java.io.Serializable; public class FlashMessage implements Serializable { private static final long serialVersionUID = 8109520737272565760L; // I have tried using different, default and no serialVersionUID public static final String SESSION_KEY = "flashMessage"; public static final String ERROR = "error"; public static final String SUCCESS = "success"; public static final String INVALID_FORM_DATA = "Your request failed to validate."; private String message; private String type; public FlashMessage (String type, String message) { this.type = type; this.message = message; } public String display(){ return "<div id='flash' class='" + type + "'>" + message + "</div>"; } }

    Read the article

  • What is the proper way to wrap this php loop around the javascript

    - by zac
    Hi, I am mashing together the Google Maps 2 script with a Wordpress loop so there is a CMS platform for the map data. I have this working fine : var point = new GLatLng(48.5139,-123.150531); var marker = createMarker(point,"Lime Kiln State Park", '<?php $post_id = 182; $my_post = get_post($post_id); $mapTitle = $my_post->post_title; $mapIMG = get_post_meta($post_id, 'mapImage', true); $snip = get_post_meta($post_id, 'mapExcerpt', true); echo "<div class=\"span-12\">"; echo "<div class=\"mapTitle\">"; echo $mapTitle; echo "</div>"; echo "<img class=\"mapImage\" src=\""; echo bloginfo('url'); echo "/wp-content/files_mf/"; echo $mapIMG; echo "\" /> "; echo "<div class=\"mapContent\">"; echo $snip; echo "</div>"; echo "<div class=\"moreLink\">"; echo "<a href=\""; echo $permalink = get_permalink( $post_id ); echo "\">Find out more &raquo; </a>"; echo "</div>"; echo "</div>"; ?>') map.addOverlay(marker); However I am hoping to also be able to include the two variables at the start within the php loop so that both of those can also be generated by custom fields. Can someone please show me that the proper way to write this would be so that all of the data can be pulled in from fields within that post id? So the lat/long and title could also be set from within the post 182 fields.

    Read the article

  • How dangerous is e.preventDefault();, and can it be replaced by keydown/mousedown tracking?

    - by yc
    I'm working on a tracking script for a fairly sophisticated CRM for tracking form actions in Google Analytics. I'm trying to balance the desire to track form actions accurately with the need to never prevent a form from not working. Now, I know that doing something like this doesn't work. $('form').submit(function(){ _gaq.push('_trackEvent', 'Form', 'Submit', $(this).attr('action')) }); The DOM unloads before this has a chance to process. So, a lot of sample code recommends something like this: $('form').submit(function(e){ e.preventDefault(); var form = this; _gaq.push('_trackEvent', 'Form', 'Submit', $(this).attr('action')); //...do some other tracking stuff... setTimeout(function(){ form.submit(); }, 400); }); This is reliable in most cases, but it makes me nervous. What if something happens between e.preventDefault();and when I get around to triggering the DOM based submit? I've totally broken the form. I've been poking around some other analytics implementations, and I've noticed something like this: $('form').mousedown(function(){ _gaq.push('_trackEvent', 'Form', 'Submit', $(this).attr('action')); }); $('form').keydown(function(e){ if(e.which===13) //if the keydown is the enter key _gaq.push('_trackEvent', 'Form', 'Submit', $(this).attr('action')); }); Basically, instead of interrupting the form submit, preempting it by assuming that if someone is mousing down or keying down on Enter, than that form is submitted. Obviously, this will result in a certain amount of false positives, but it completely eliminates use of e.preventDefault();, which in my mind eliminates the risk that I might ever prevent a form from successfully submitting. So, my question: Is it possible to take the standard form tracking snippet and prevent it from ever fully preventing the form from submitting? Is the mousedown/keydown alternative viable? Are there any submission cases it may miss? Specifically, are there other ways to end up submitting besides the mouse and the keyboard enter? And will the browser always have time to process javascript before beginning to unload the page?

    Read the article

  • How to read & write contents of a div from localstorage in chrome extensions?

    - by Minas Abovyan
    I am trying to build an extension that will allow users to put some parameters into a text box in the popup, generate a link using that information and add it to the said popup. I have all that working, but needless to say, it gets flushed every time the user opens the extension anew. I'd like the info that has been put in there to stay, but can't seem to get it to work. Here's what I have thus far: manifest.json { "manifest_version": 2, "name": "Test", "description": "Test Extension", "version": "1.0", "permissions": [ "http://*/*", "https://*/*" ], "browser_action": { "default_title": "This is a test", "default_popup": "popup.html" } } popup.html <!DOCTYPE html> <html> <head> </head> <body> <div id="linkContainer"/> <input type="text" id="catsList"/> <button type="button" id="addToList">Add</button> <script src="popup.js"></script> </body> </html> popup.js function addCats() { var a = document.createElement('a'); a.appendChild(document.createTextNode(document.getElementById('catsList').value)); a.setAttribute('href', 'http://google.com'); var p = document.createElement('p'); p.appendChild(a) document.getElementById('linkContainer').appendChild(p); indexLinks() } function indexLinks() { var links = document.getElementsByTagName("a"); for (var i = 0; i < links.length; i++) { (function () { var ln = links[i]; var location = ln.href; ln.onclick = function () { chrome.tabs.create({active: true, url: location}); }; })(); } }; document.getElementById('addToList').onclick = addCats; My guess is that I need something along the lines of localStorage['cointainer'] = document.getElementById('linkContainer'); at the end of addCats() and a call to something like function loadLocalStorage() { var container = document.getElementById('linkContainer'); container.innerHTML = localStorage['container']; } at the beginning, but doing that didn't work. Not sure what's going wrong. Also,if there is a different way to save users' additions, I'd be open to them.

    Read the article

  • Users and roles in context

    - by Eric W.
    I'm trying to get a sense of how to implement the user/role relationships for an application I'm writing. The persistence layer is Google App Engine's datastore, which places some interesting (but generally beneficial) constraints on what can be done. Any thoughts are appreciated. It might be helpful to keep things very concrete. I would like there to be organizations, users, test content and test administrations (records of tests that have been taken). A user can have the role of participant (test-taker), contributor of test material or both. A user can also be a member of zero or more organizations. In the role of participant, the user can see the previous administrations of tests he or she has taken. The user can also see a test administration of another participant if that participant has given the user authorization. The user can see test material that has been made public, and he or she can see restricted content as a participant during a specific administration of a test for which that user has been authorized by an organization. As a member of an organization, the user can see restricted content in the role of contributor, and he or she might or might not also be able to edit the content. Each organization should have one or more administrators that can determine whether a member can see and edit content and determine who has admin privileges. There should also be one or more application-wide superusers that can troubleshoot and solve problems. Members of organizations can see the administrations of tests that the participants concerned have authorized them to see, and they can see anonymous data if no authorization has been given. A user cannot see the test results of another user in any other circumstances. Since there are no joins in the App Engine datastore, it might be necessary to have things less normalized than usual for the typical SQL database in order to ensure that queries that check permissions are fast (e.g., ones that determine whether a link is to be displayed). My questions are: How do I move forward on this? Should I spend a lot of time up front in order to get the model right, or can I iterate several times and gradually roll in additional complexity? Does anyone have some general ideas about how to break things up in this instance? Are there any GAE libraries that handle roles in a way that is compatible with this arrangement?

    Read the article

  • Saving twice don't update my object in JDO

    - by Javi
    Hello I have an object persisted in the GAE datastore using JDO. The object looks like this: public class MyObject implements Serializable, StoreCallback { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) @Extension(vendorName="datanucleus", key="gae.encoded-pk", value="true") private String id; @Persistent private String firstId; ... } As usually when the object is stored for the first time a new id value is generated for the identifier. I need that if I don't provide a value for firstId it sets the same value as the id. I don't want to solve it with a special getter which checks for null value in firstId and then return the id value because I want to make queries relating on firstId. I can do it in this way by saving the object twice (Probably there's a better way to do this, but I'll do it in this way until I find a better one). But it is not working. when I debug it I can see that result.firstId is set with the id value and it seems to be persisted, but when I go into the datastore I see that firstId is null (as it was saved the first time). This save method is in my DAO and it is called in another save method in the service annotated with @Transactional. Does anyone have any idea why the second object in not persisted properly? @Override public MyObject save(MyObject obj) { PersistenceManager pm = JDOHelper.getPersistenceManagerFactory("transactions-optional"); MyObject result = pm.makePersistent(obj); if(result.getFirstId() == null){ result.setFirstId(result.getId()); result = pm.makePersistent(result); } return result; } Thanks.

    Read the article

  • Passing an ActionScript JPG Byte Array to Javscript (and eventually to PHP)

    - by Gus
    Our web application has a feature which uses Flash (AS3) to take photos using the user's web cam, then passes the resulting byte array to PHP where it is reconstructed and saved on the server. However, we need to be able to take this web application offline, and we have chosen Gears to do so. The user takes the app offline, performs his tasks, then when he's reconnected to the server, we "sync" the data back with our central database. We don't have PHP to interact with Flash anymore, but we still need to allow users to take and save photos. We don't know how to save a JPG that Flash creates in a local database. Our hope was that we could save the byte array, a serialized string, or somehow actually persist the object itself, then pass it back to either PHP or Flash (and then PHP) to recreate the JPG. We have tried: - passing the byte array to Javascript instead of PHP, but javascript doesn't seem to be able to do anything with it (the object seems to be stripped of its methods) - stringifying the byte array in Flash, and then passing it to Javascript, but we always get the same string: ÿØÿà Now we are thinking of serializing the string in Flash, passing it to Javascript, then on the return route, passing that string back to Flash which will then pass it to PHP to be reconstructed as a JPG. (whew). Since no one on our team has extensive Flash background, we're a bit lost. Is serialization the way to go? Is there a more realistic way to do this? Does anyone have any experience with this sort of thing? Perhaps we can build a javascript class that is the same as the byte array class in AS?

    Read the article

  • Unable to persist objects in GAE JDO

    - by Basil Dsouza
    Hello Guys, I am completely fresh to both JDO and GAE, and have been struggling to get my data layer to persist any code at all! The issues I am facing may be very simple, but I just cant seem to find any a way no matter what solution I try. Firstly the problem: (Slightly simplified, but still contains all the info necessary) My data model is as such: User: (primary key) String emailID String firstName Car: (primary key) User user (primary key) String registration String model This was the initial datamodel. I implemented a CarPK object to get a composite primary key of the User and the registration. However that ran into a variety of issues. (Which i will save for another time/question) I then changed the design as such: User: (Unchanged) Car: (primary key) String fauxPK (here fauxPK = user.getEmailID() + SEP + registration) User user String registration String model This works fine for the user, and it can insert and retrieve user objects. However when i try to insert a Car Object, i get the following error: "Cannot have a java.lang.String primary key and be a child object" Found the following helpful link about it: http://stackoverflow.com/questions/2063467/persist-list-of-objects Went to the link suggested there, that explains how to create Keys, however they keep talking about "Entity Groups" and "Entity Group Parents". But I cant seem to find any articles or sites that explain what are "Entity Group"s or an "Entity Group Parents" I could try fiddling around some more to figure out if i can store an object somehow, But I am running sort on patience and also would rather understand and implement than vice versa. So i would appreciate any docs (even if its huge) that covers all these points, and preferably has some examples that go beyond the very basic data modeling. And thanks for reading such a long post :)

    Read the article

  • Many users, many cpus, no delays. Good for cloud?

    - by Eric
    I wish to set up a CPU-intensive time-important query service for users on the internet. A usage scenario is described below. Is cloud computing the right way to go for such an implementation? If so, what cloud vendor(s) cater to this type of application? I ask specifically, in terms of: 1) pricing 2) latency resulting from: - slow CPUs, instance creations, JIT compiles, etc.. - internal management and communication of processes inside the cloud (e.g. a queuing process and a calculation process) - communication between cloud and end user 3) ease of deployment A usage scenario I am expecting is: - A typical user sends a query (XML of size around 1K) once every 30 seconds on average. - Each query requires a numerical computation of average time 0.2 sec and max time 1 sec on a 1 GHz Pentium. The computation requires no data other than the query itself and is performed by the same piece of code each time. - The delay a user experiences between sending a query and receiving a response should be on average no more than 2 seconds and in general no more than 5 seconds. - A background save to a DB of the response should occur (not time critical) - There can be up to 30000 simultaneous users - i.e., on average 1000 queries a second, each requiring an average 0.2 sec calculation, so that would necessitate around 200 CPUs. Currently I'm look at GAE Java (for quicker deployment and less IT hassle) and EC2 (Speed and price optimization) as options. Where can I learn more about the right way to set ups such a system? past threads, different blogs, books, etc.. BTW, if my terminology is wrong or confusing, please let me know. I'd greatly appreciate any help.

    Read the article

  • Doing a global count of an object type (like Users), best practice?

    - by user246114
    Hi, I know keeping global counters is frowned upon in app engine. I am interested in getting some stats though, like once every 24 hours. For example, I'd like to count the number of User objects in the system once every 24 hours. So how do we do this? Do we simply keep a set of admin tool functions which do something like: SELECT FROM com.me.project.server.User; and just see what the size of the returned List is? This is kind of a bummer because the datastore would have to deserialize every single User instance to create the returned list, right? I could optimize this possibly by asking for only the keys to be returned, so the whole User object doesn't have to be deserialized. Then again, a global counter for # of users probably would create too much contention, because there probably won't be hundreds of signups a minute for the service I'm creating. How should we go about doing this? Getting my total number of users once a day is probably a pretty typical operation? Thank you

    Read the article

  • "Content is not allowed in prolog" when parsing perfectly valid XML on GAE

    - by Adrian Petrescu
    Hey guys, I've been beating my head against this absolutely infuriating bug for the last 48 hours, so I thought I'd finally throw in the towel and try asking here before I throw my laptop out the window. I'm trying to parse the response XML from a call I made to AWS SimpleDB. The response is coming back on the wire just fine; for example, it may look like: <?xml version="1.0" encoding="utf-8"?> <ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/"> <ListDomainsResult> <DomainName>Audio</DomainName> <DomainName>Course</DomainName> <DomainName>DocumentContents</DomainName> <DomainName>LectureSet</DomainName> <DomainName>MetaData</DomainName> <DomainName>Professors</DomainName> <DomainName>Tag</DomainName> </ListDomainsResult> <ResponseMetadata> <RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId> <BoxUsage>0.0000071759</BoxUsage> </ResponseMetadata> </ListDomainsResponse> I pass in this XML to a parser with XMLEventReader eventReader = xmlInputFactory.createXMLEventReader(response.getContent()); and call eventReader.nextEvent(); a bunch of times to get the data I want. Here's the bizarre part -- it works great inside the local server. The response comes in, I parse it, everyone's happy. The problem is that when I deploy the code to Google App Engine, the outgoing request still works, and the response XML seems 100% identical and correct to me, but the response fails to parse with the following exception: com.amazonaws.http.HttpClient handleResponse: Unable to unmarshall response (ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog.): <?xml version="1.0" encoding="utf-8"?> <ListDomainsResponse xmlns="http://sdb.amazonaws.com/doc/2009-04-15/"><ListDomainsResult><DomainName>Audio</DomainName><DomainName>Course</DomainName><DomainName>DocumentContents</DomainName><DomainName>LectureSet</DomainName><DomainName>MetaData</DomainName><DomainName>Professors</DomainName><DomainName>Tag</DomainName></ListDomainsResult><ResponseMetadata><RequestId>42330b4a-e134-6aec-e62a-5869ac2b4575</RequestId><BoxUsage>0.0000071759</BoxUsage></ResponseMetadata></ListDomainsResponse> javax.xml.stream.XMLStreamException: ParseError at [row,col]:[1,1] Message: Content is not allowed in prolog. at com.sun.org.apache.xerces.internal.impl.XMLStreamReaderImpl.next(Unknown Source) at com.sun.xml.internal.stream.XMLEventReaderImpl.nextEvent(Unknown Source) at com.amazonaws.transform.StaxUnmarshallerContext.nextEvent(StaxUnmarshallerContext.java:153) ... (rest of lines omitted) I have double, triple, quadruple checked this XML for 'invisible characters' or non-UTF8 encoded characters, etc. I looked at it byte-by-byte in an array for byte-order-marks or something of that nature. Nothing; it passes every validation test I could throw at it. Even stranger, it happens if I use a Saxon-based parser as well -- but ONLY on GAE, it always works fine in my local environment. It makes it very hard to trace the code for problems when I can only run the debugger on an environment that works perfectly (I haven't found any good way to remotely debug on GAE). Nevertheless, using the primitive means I have, I've tried a million approaches including: XML with and without the prolog With and without newlines With and without the "encoding=" attribute in the prolog Both newline styles With and without the chunking information present in the HTTP stream And I've tried most of these in multiple combinations where it made sense they would interact -- nothing! I'm at my wit's end. Has anyone seen an issue like this before that can hopefully shed some light on it? Thanks!

    Read the article

  • Persistance JDO - How to query a property of a collection with JDOQL?

    - by Sergio del Amo
    I want to build an application where a user identified by an email address can have several application accounts. Each account can have one o more users. I am trying to use the JDO Storage capabilities with Google App Engine Java. Here is my attempt: @PersistenceCapable @Inheritance(strategy = InheritanceStrategy.NEW_TABLE) public class AppAccount { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) private Long id; @Persistent private String companyName; @Persistent List<Invoices> invoices = new ArrayList<Invoices>(); @Persistent List<AppUser> users = new ArrayList<AppUser>(); // Getter Setters and Other Fields } @PersistenceCapable @EmbeddedOnly public class AppUser { @Persistent private String username; @Persistent private String firstName; @Persistent private String lastName; // Getter Setters and Other Fields } When a user logs in, I want to check how many accounts does he belongs to. If he belongs to more than one he will be presented with a dashboard where he can click which account he wants to load. This is my code to retrieve a list of app accounts where he is registered. public static List<AppAccount> getUserAppAccounts(String username) { PersistenceManager pm = JdoUtil.getPm(); Query q = pm.newQuery(AppAccount.class); q.setFilter("users.username == usernameParam"); q.declareParameters("String usernameParam"); return (List<AppAccount>) q.execute(username); } But I get the next error: SELECT FROM invoices.server.AppAccount WHERE users.username == usernameParam PARAMETERS String usernameParam: Encountered a variable expression that isn't part of a join. Maybe you're referencing a non-existent field of an embedded class. org.datanucleus.store.appengine.FatalNucleusUserException: SELECT FROM com.softamo.pelicamo.invoices.server.AppAccount WHERE users.username == usernameParam PARAMETERS String usernameParam: Encountered a variable expression that isn't part of a join. Maybe you're referencing a non-existent field of an embedded class. at org.datanucleus.store.appengine.query.DatastoreQuery.getJoinClassMetaData(DatastoreQuery.java:1154) at org.datanucleus.store.appengine.query.DatastoreQuery.addLeftPrimaryExpression(DatastoreQuery.java:1066) at org.datanucleus.store.appengine.query.DatastoreQuery.addExpression(DatastoreQuery.java:846) at org.datanucleus.store.appengine.query.DatastoreQuery.addFilters(DatastoreQuery.java:807) at org.datanucleus.store.appengine.query.DatastoreQuery.performExecute(DatastoreQuery.java:226) at org.datanucleus.store.appengine.query.JDOQLQuery.performExecute(JDOQLQuery.java:85) at org.datanucleus.store.query.Query.executeQuery(Query.java:1489) at org.datanucleus.store.query.Query.executeWithArray(Query.java:1371) at org.datanucleus.jdo.JDOQuery.execute(JDOQuery.java:243) at com.softamo.pelicamo.invoices.server.Store.getUserAppAccounts(Store.java:82) at com.softamo.pelicamo.invoices.test.server.StoreTest.testgetUserAppAccounts(StoreTest.java:39) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28) at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184) at org.junit.runners.ParentRunner.run(ParentRunner.java:236) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Any idea? I am getting JDO persistance totally wrong?

    Read the article

< Previous Page | 337 338 339 340 341 342 343 344 345 346 347 348  | Next Page >