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  • java.lang.ExceptionInInitializerError Exception when creating Application Context in Spring

    - by cyotee
    I am practicing with Spring, and am getting a java.lang.ExceptionInInitializerError exception when I try to instantiate the context. The Exception appears below, with my code following it. I have simplified my experiment from before. The Exception Oct 17, 2012 5:54:22 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@570c16b7: startup date [Wed Oct 17 17:54:22 CDT 2012]; root of context hierarchy Exception in thread "main" java.lang.ExceptionInInitializerError at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:195) at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:128) at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:535) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:449) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83) at helloworld.HelloWorldTest.main(HelloWorldTest.java:13) Caused by: java.lang.NullPointerException at org.springframework.beans.factory.support.DefaultListableBeanFactory.<clinit>(DefaultListableBeanFactory.java:105) ... 7 more My configuration XML <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:c="http://www.springframework.org/schema/c" xmlns:p="http://www.springframework.org/schema/p" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd"> <bean id="messageContainer" class="helloworld.MessageContainer"> <property name="message" value="Hello World"> </property> </bean> <bean id="messageOutputService" class="helloworld.MessageOutputService"> </bean> My test class. package helloworld; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; public class HelloWorldTest { /** * @param args */ public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("HelloWorldTest-context.xml"); MessageContainer message = context.getBean(MessageContainer.class); MessageOutputService service = context.getBean(MessageOutputService.class); service.outputMessageToConsole(message); } }

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  • Big Data – Buzz Words: What is Hadoop – Day 6 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned what is NoSQL. In this article we will take a quick look at one of the four most important buzz words which goes around Big Data – Hadoop. What is Hadoop? Apache Hadoop is an open-source, free and Java based software framework offers a powerful distributed platform to store and manage Big Data. It is licensed under an Apache V2 license. It runs applications on large clusters of commodity hardware and it processes thousands of terabytes of data on thousands of the nodes. Hadoop is inspired from Google’s MapReduce and Google File System (GFS) papers. The major advantage of Hadoop framework is that it provides reliability and high availability. What are the core components of Hadoop? There are two major components of the Hadoop framework and both fo them does two of the important task for it. Hadoop MapReduce is the method to split a larger data problem into smaller chunk and distribute it to many different commodity servers. Each server have their own set of resources and they have processed them locally. Once the commodity server has processed the data they send it back collectively to main server. This is effectively a process where we process large data effectively and efficiently. (We will understand this in tomorrow’s blog post). Hadoop Distributed File System (HDFS) is a virtual file system. There is a big difference between any other file system and Hadoop. When we move a file on HDFS, it is automatically split into many small pieces. These small chunks of the file are replicated and stored on other servers (usually 3) for the fault tolerance or high availability. (We will understand this in the day after tomorrow’s blog post). Besides above two core components Hadoop project also contains following modules as well. Hadoop Common: Common utilities for the other Hadoop modules Hadoop Yarn: A framework for job scheduling and cluster resource management There are a few other projects (like Pig, Hive) related to above Hadoop as well which we will gradually explore in later blog posts. A Multi-node Hadoop Cluster Architecture Now let us quickly see the architecture of the a multi-node Hadoop cluster. A small Hadoop cluster includes a single master node and multiple worker or slave node. As discussed earlier, the entire cluster contains two layers. One of the layer of MapReduce Layer and another is of HDFC Layer. Each of these layer have its own relevant component. The master node consists of a JobTracker, TaskTracker, NameNode and DataNode. A slave or worker node consists of a DataNode and TaskTracker. It is also possible that slave node or worker node is only data or compute node. The matter of the fact that is the key feature of the Hadoop. In this introductory blog post we will stop here while describing the architecture of Hadoop. In a future blog post of this 31 day series we will explore various components of Hadoop Architecture in Detail. Why Use Hadoop? There are many advantages of using Hadoop. Let me quickly list them over here: Robust and Scalable – We can add new nodes as needed as well modify them. Affordable and Cost Effective – We do not need any special hardware for running Hadoop. We can just use commodity server. Adaptive and Flexible – Hadoop is built keeping in mind that it will handle structured and unstructured data. Highly Available and Fault Tolerant – When a node fails, the Hadoop framework automatically fails over to another node. Why Hadoop is named as Hadoop? In year 2005 Hadoop was created by Doug Cutting and Mike Cafarella while working at Yahoo. Doug Cutting named Hadoop after his son’s toy elephant. Tomorrow In tomorrow’s blog post we will discuss Buzz Word – MapReduce. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • Master Data Management for Location Data - Oracle Site Hub

    - by david.butler(at)oracle.com
    Most MDM discussions cover key domains such as customer, supplier, product, service, and reference data. It is usually understood that these domains have complex structures and hundreds if not thousands of attributes that need governing. Location, on the other hand, strikes most people as address data. How hard can that be? But for many industries, locations are complex, and site information is critical to efficient operations and relevant analytics. Retail stores and malls, bank branches, construction sites come to mind. But one of the best industries for illustrating the power of a site mastering application is Oil & Gas.   Oracle's Master Data Management solution for location data is the Oracle Site Hub. It is a location mastering solution that enables organizations to centralize site and location specific information from heterogeneous systems, creating a single view of site information that can be leveraged across all functional departments and analytical systems.   Let's take a look at the location entities the Oracle Site Hub can manage for the Oil & Gas industry: organizations, property, land, buildings, roads, oilfield, service center, inventory site, real estate, facilities, refineries, storage tanks, vendor locations, businesses, assets; project site, area, well, basin, pipelines, critical infrastructure, offshore platform, compressor station, gas station, etc. Any site can be classified into multiple hierarchies, like organizational hierarchy, operational hierarchy, geographic hierarchy, divisional hierarchies and so on. Any site can also be associated to multiple clusters, i.e. collections of sites, and these can be used as a foundation for driving reporting, analysis, organize daily work, etc. Hierarchies can also be used to model entities which are structured or non-structured collections of nodes, like for example routes, pipelines and more. The User Defined Attribute Framework provides the needed infrastructure to add single row attributes groups like well base attributes (well IDs, well type, well structure and key characterizing measures, and more) and well geometry, and multi row attribute groups like well applications, permits, production data, activities, operations, logs, treatments, tests, drills, treatments, and KPIs. Site Hub can also model areas, lands, fields, basins, pools, platforms, eco-zones, and stratigraphic layers as specific sites, tracking their base attributes, aliases, descriptions, subcomponents and more. Midstream entities (pipelines, logistic sites, pump stations) and downstream entities (cylinders, tanks, inventories, meters, partner's sites, routes, facilities, gas stations, and competitor sites) can also be easily modeled, together with their specific attributes and relationships. Site Hub can store any type of unstructured data associated to a site. This could be stored directly or on an external content management solution, like Oracle Universal Content Management. Considering a well, for example, Site Hub can store any relevant associated multimedia file such as: CAD drawings of the well profile, structure and/or parts, engineering documents, contracts, applications, permits, logs, pictures, photos, videos and more. For any site entity, Site Hub can associate all the related assets and equipments at the site, as well as all relationships between sites, between a site and multiple parties, and between a site and any purchasable or sellable item, over time. Items can be equipment, instruments, facilities, services, products, production entities, production facilities (pipelines, batteries, compressor stations, gas plants, meters, separators, etc.), support facilities (rigs, roads, transmission or radio towers, airstrips, etc.), supplier products and services, catalogs, and more. Items can just be associated to sites using standard Site Hub features, or they can be fully mastered by implementing Oracle Product Hub. Site locations (addresses or geographical coordinates) are also managed with out-of-the-box address geo-coding capabilities coupled with Google Maps integration to deliver powerful mapping capabilities and spatial data analysis. Locations can be shared between different sites. Centered on the site location, any site can also have associated areas. Site Hub can master any site location specific information, like for example cadastral, ownership, jurisdictional, geological, seismic and more, and any site-centric area specific information, like for example economical, political, risk, weather, logistic, traffic information and more. Now if anyone ever asks you why locations need MDM, think about how all these Oil & Gas entities and attributes would translate into your business locations. To learn more about Oracle's full MDM solution for the digital oil field, here is a link to Roberto Negro's outstanding whitepaper: Oracle Site Master Data Management for mastering wells and other PPDM entities in a digital oilfield context  

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  • Optimal Data Structure for our own API

    - by vermiculus
    I'm in the early stages of writing an Emacs major mode for the Stack Exchange network; if you use Emacs regularly, this will benefit you in the end. In order to minimize the number of calls made to Stack Exchange's API (capped at 10000 per IP per day) and to just be a generally responsible citizen, I want to cache the information I receive from the network and store it in memory, waiting to be accessed again. I'm really stuck as to what data structure to store this information in. Obviously, it is going to be a list. However, as with any data structure, the choice must be determined by what data is being stored and what how it will be accessed. What, I would like to be able to store all of this information in a single symbol such as stack-api/cache. So, without further ado, stack-api/cache is a list of conses keyed by last update: `(<csite> <csite> <csite>) where <csite> would be (1362501715 . <site>) At this point, all we've done is define a simple association list. Of course, we must go deeper. Each <site> is a list of the API parameter (unique) followed by a list questions: `("codereview" <cquestion> <cquestion> <cquestion>) Each <cquestion> is, you guessed it, a cons of questions with their last update time: `(1362501715 <question>) (1362501720 . <question>) <question> is a cons of a question structure and a list of answers (again, consed with their last update time): `(<question-structure> <canswer> <canswer> <canswer> and ` `(1362501715 . <answer-structure>) This data structure is likely most accurately described as a tree, but I don't know if there's a better way to do this considering the language, Emacs Lisp (which isn't all that different from the Lisp you know and love at all). The explicit conses are likely unnecessary, but it helps my brain wrap around it better. I'm pretty sure a <csite>, for example, would just turn into (<epoch-time> <api-param> <cquestion> <cquestion> ...) Concerns: Does storing data in a potentially huge structure like this have any performance trade-offs for the system? I would like to avoid storing extraneous data, but I've done what I could and I don't think the dataset is that large in the first place (for normal use) since it's all just human-readable text in reasonable proportion. (I'm planning on culling old data using the times at the head of the list; each inherits its last-update time from its children and so-on down the tree. To what extent this cull should take place: I'm not sure.) Does storing data like this have any performance trade-offs for that which must use it? That is, will set and retrieve operations suffer from the size of the list? Do you have any other suggestions as to what a better structure might look like?

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  • Set Context User Principal for Customized Authentication in SignalR

    - by Shaun
    Originally posted on: http://geekswithblogs.net/shaunxu/archive/2014/05/27/set-context-user-principal-for-customized-authentication-in-signalr.aspxCurrently I'm working on a single page application project which is built on AngularJS and ASP.NET WebAPI. When I need to implement some features that needs real-time communication and push notifications from server side I decided to use SignalR. SignalR is a project currently developed by Microsoft to build web-based, read-time communication application. You can find it here. With a lot of introductions and guides it's not a difficult task to use SignalR with ASP.NET WebAPI and AngularJS. I followed this and this even though it's based on SignalR 1. But when I tried to implement the authentication for my SignalR I was struggled 2 days and finally I got a solution by myself. This might not be the best one but it actually solved all my problem.   In many articles it's said that you don't need to worry about the authentication of SignalR since it uses the web application authentication. For example if your web application utilizes form authentication, SignalR will use the user principal your web application authentication module resolved, check if the principal exist and authenticated. But in my solution my ASP.NET WebAPI, which is hosting SignalR as well, utilizes OAuth Bearer authentication. So when the SignalR connection was established the context user principal was empty. So I need to authentication and pass the principal by myself.   Firstly I need to create a class which delivered from "AuthorizeAttribute", that will takes the responsible for authenticate when SignalR connection established and any method was invoked. 1: public class QueryStringBearerAuthorizeAttribute : AuthorizeAttribute 2: { 3: public override bool AuthorizeHubConnection(HubDescriptor hubDescriptor, IRequest request) 4: { 5: } 6:  7: public override bool AuthorizeHubMethodInvocation(IHubIncomingInvokerContext hubIncomingInvokerContext, bool appliesToMethod) 8: { 9: } 10: } The method "AuthorizeHubConnection" will be invoked when any SignalR connection was established. And here I'm going to retrieve the Bearer token from query string, try to decrypt and recover the login user's claims. 1: public override bool AuthorizeHubConnection(HubDescriptor hubDescriptor, IRequest request) 2: { 3: var dataProtectionProvider = new DpapiDataProtectionProvider(); 4: var secureDataFormat = new TicketDataFormat(dataProtectionProvider.Create()); 5: // authenticate by using bearer token in query string 6: var token = request.QueryString.Get(WebApiConfig.AuthenticationType); 7: var ticket = secureDataFormat.Unprotect(token); 8: if (ticket != null && ticket.Identity != null && ticket.Identity.IsAuthenticated) 9: { 10: // set the authenticated user principal into environment so that it can be used in the future 11: request.Environment["server.User"] = new ClaimsPrincipal(ticket.Identity); 12: return true; 13: } 14: else 15: { 16: return false; 17: } 18: } In the code above I created "TicketDataFormat" instance, which must be same as the one I used to generate the Bearer token when user logged in. Then I retrieve the token from request query string and unprotect it. If I got a valid ticket with identity and it's authenticated this means it's a valid token. Then I pass the user principal into request's environment property which can be used in nearly future. Since my website was built in AngularJS so the SignalR client was in pure JavaScript, and it's not support to set customized HTTP headers in SignalR JavaScript client, I have to pass the Bearer token through request query string. This is not a restriction of SignalR, but a restriction of WebSocket. For security reason WebSocket doesn't allow client to set customized HTTP headers from browser. Next, I need to implement the authentication logic in method "AuthorizeHubMethodInvocation" which will be invoked when any SignalR method was invoked. 1: public override bool AuthorizeHubMethodInvocation(IHubIncomingInvokerContext hubIncomingInvokerContext, bool appliesToMethod) 2: { 3: var connectionId = hubIncomingInvokerContext.Hub.Context.ConnectionId; 4: // check the authenticated user principal from environment 5: var environment = hubIncomingInvokerContext.Hub.Context.Request.Environment; 6: var principal = environment["server.User"] as ClaimsPrincipal; 7: if (principal != null && principal.Identity != null && principal.Identity.IsAuthenticated) 8: { 9: // create a new HubCallerContext instance with the principal generated from token 10: // and replace the current context so that in hubs we can retrieve current user identity 11: hubIncomingInvokerContext.Hub.Context = new HubCallerContext(new ServerRequest(environment), connectionId); 12: return true; 13: } 14: else 15: { 16: return false; 17: } 18: } Since I had passed the user principal into request environment in previous method, I can simply check if it exists and valid. If so, what I need is to pass the principal into context so that SignalR hub can use. Since the "User" property is all read-only in "hubIncomingInvokerContext", I have to create a new "ServerRequest" instance with principal assigned, and set to "hubIncomingInvokerContext.Hub.Context". After that, we can retrieve the principal in my Hubs through "Context.User" as below. 1: public class DefaultHub : Hub 2: { 3: public object Initialize(string host, string service, JObject payload) 4: { 5: var connectionId = Context.ConnectionId; 6: ... ... 7: var domain = string.Empty; 8: var identity = Context.User.Identity as ClaimsIdentity; 9: if (identity != null) 10: { 11: var claim = identity.FindFirst("Domain"); 12: if (claim != null) 13: { 14: domain = claim.Value; 15: } 16: } 17: ... ... 18: } 19: } Finally I just need to add my "QueryStringBearerAuthorizeAttribute" into the SignalR pipeline. 1: app.Map("/signalr", map => 2: { 3: // Setup the CORS middleware to run before SignalR. 4: // By default this will allow all origins. You can 5: // configure the set of origins and/or http verbs by 6: // providing a cors options with a different policy. 7: map.UseCors(CorsOptions.AllowAll); 8: var hubConfiguration = new HubConfiguration 9: { 10: // You can enable JSONP by uncommenting line below. 11: // JSONP requests are insecure but some older browsers (and some 12: // versions of IE) require JSONP to work cross domain 13: // EnableJSONP = true 14: EnableJavaScriptProxies = false 15: }; 16: // Require authentication for all hubs 17: var authorizer = new QueryStringBearerAuthorizeAttribute(); 18: var module = new AuthorizeModule(authorizer, authorizer); 19: GlobalHost.HubPipeline.AddModule(module); 20: // Run the SignalR pipeline. We're not using MapSignalR 21: // since this branch already runs under the "/signalr" path. 22: map.RunSignalR(hubConfiguration); 23: }); On the client side should pass the Bearer token through query string before I started the connection as below. 1: self.connection = $.hubConnection(signalrEndpoint); 2: self.proxy = self.connection.createHubProxy(hubName); 3: self.proxy.on(notifyEventName, function (event, payload) { 4: options.handler(event, payload); 5: }); 6: // add the authentication token to query string 7: // we cannot use http headers since web socket protocol doesn't support 8: self.connection.qs = { Bearer: AuthService.getToken() }; 9: // connection to hub 10: self.connection.start(); 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 do you handle the fetchxml result data?

    - by Luke Baulch
    I have avoided working with fetchxml as I have been unsure the best way to handle the result data after calling crmService.Fetch(fetchXml). In a couple of situations, I have used an XDocument with LINQ to retrieve the data from this data structure, such as: XDocument resultset = XDocument.Parse(_service.Fetch(fetchXml)); if (resultset.Root == null || !resultset.Root.Elements("result").Any()) { return; } foreach (var displayItem in resultset.Root.Elements("result").Select(item => item.Element(displayAttributeName)).Distinct()) { if (displayItem!= null && displayItem.Value != null) { dropDownList.Items.Add(displayItem.Value); } } What is the best way to handle fetchxml result data, so that it can be easily used. Applications such as passing these records into an ASP.NET datagrid would be quite useful.

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  • Generate Entity Data Model from Data Contract

    - by CSmooth.net
    I would like to find a fast way to convert a Data Contract to a Entity Data Model. Consider the following Data Contract: [DataContract] class PigeonHouse { [DataMember] public string housename; [DataMember] public List<Pigeon> pigeons; } [DataContract] class Pigeon { [DataMember] public string name; [DataMember] public int numberOfWings; [DataMember] public int age; } Is there an easy way to create an ADO.NET Entity Data Model from this code?

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  • Insert new relationship data in core data

    - by michael
    Hoping someone can shed some light on what I might be doing wrong here. Trying to add an "event" to a list of events, represented by a one to many (inverse) relationship: MyEvents <--- Event This is the code: MyEvents *myEvents = (MyEvents *)[NSEntityDescription insertNewObjectForEntityForName:@"MyEvents" inManagedObjectContext:context]; NSLog(@"MYEVENTS: %@", myEvents); NSLog(@"EVENT: %@", event); [myEvents addEventObject:event]; My context is fine, and both the myEvents and event print perfectly valid information. When I try to add the event that I have (which is passed into this view controller, having been retrieved from core data previously) with this code [myEvents addEventObject:event]; It falls over with *** -[NSComparisonPredicate evaluateWithObject:]: message sent to deallocated instance MyEvents and Event are just the default generated code. MyEvents contains only the relationship to event. Thanks.

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  • Detecting a Lightweight Core Data Migration

    - by hadronzoo
    I'm using Core Data's automatic lightweight migration successfully. However, when a particular entity gets created during a migration, I'd like to populate it with some data. Of course I could check if the entity is empty every time the application starts, but this seems inefficient when Core Data has a migration framework. Is it possible to detect when a lightweight migration occurs (possibly using KVO or notifications), or does this require implementing standard migrations? I've tried using the NSPersistentStoreCoordinatorStoresDidChangeNotification, but it doesn't fire when migrations occur.

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  • Getting started with massive data

    - by Max
    I'm a math guy and occasionally do some statistics/machine learning analysis consulting projects on the side. The data I have access to are usually on the smaller side, at most a couple hundred of megabytes (and almost always far less), but I want to learn more about handling and analyzing data on the gigabyte/terabyte scale. What do I need to know and what are some good resources to learn from? Hadoop/MapReduce is one obvious start. Is there a particular programming language I should pick up? (I primarily work now in Python, Ruby, R, and occasionally Java, but it seems like C and Clojure are often used for large-scale data analysis?) I'm not really familiar with the whole NoSQL movement, except that it's associated with big data. What's a good place to learn about it, and is there a particular implementation (Cassandra, CouchDB, etc.) I should get familiar with? Where can I learn about applying machine learning algorithms to huge amounts of data? My math background is mostly on the theory side, definitely not on the numerical or approximation side, and I'm guessing most of the standard ML algorithms don't really scale. Any other suggestions on things to learn would be great!

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  • Update tableview instantly as data pushed in core data iphone

    - by user336685
    I need to update the tableview as soon as the content is pushed in core data database. for this AppDelegate.m contains following code NSManagedObjectContext *moc = [self managedObjectContext]; NSFetchRequest *request = [[NSFetchRequest alloc] init]; [request setEntity:[NSEntityDescription entityForName:@"FeedItem" inManagedObjectContext:moc]]; //for loop // push data in code data & then save context [moc save:&error]; ZAssert(error == nil, @"Error saving context: %@", [error localizedDescription]); //for loop ends This code triggers following code from RootviewController.m - (void)controllerWillChangeContent:(NSFetchedResultsController*)controller { [[self tableView] beginUpdates]; } But this updates the tableview only at the end of the for loop ,the table does not get updated after immediate push in db. I tried following code but that didn't work - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller { // In the simplest, most efficient, case, reload the table view. [self.tableView reloadData]; } I have been stuck with this problem for several days.Please help.Thanks in advance for solution.

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  • what is best way to store long term data in iphone Core Data or SQLLite?

    - by AmitSri
    Hi all, I am working on i-Phone app targeting 3.1.3 and later SDK. I want to know the best way to store user's long term data on i-phone without losing performance, consistency and security. I know, that i can use Core Data, PList and SQL-Lite for storing user specific data in custom formats.But, want to know which one is good to use without compromising app performance and scalability in near future. Thanks

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  • How to view existing data in Core Data?

    - by mshsayem
    Well, may be this question is silly, but I couldn't find a way (except programmatically). I built a project (for iPhone OS 3.0) which uses Core Data. The xcdatamodel file shows the schema description, but I want to see the data in tabular form (like the management studio for mssql server or phpmyadmin for mysql). Is there any way (except coding)? What is that? Also, which file (in disk/device) those data are stored into? [ I built the tutorial (from apple) on Core Data, named Locations. They used this line somewhere in the code: NSURL *storeUrl = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"Locations.sqlite"]]; But, I did not see any "xxxxx.sqlite" file in project location (nor in the disk).]

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  • Efficient alternatives to merge for larger data.frames R

    - by Etienne Low-Décarie
    I am looking for an efficient (both computer resource wise and learning/implementation wise) method to merge two larger (size1 million / 300 KB RData file) data frames. "merge" in base R and "join" in plyr appear to use up all my memory effectively crashing my system. Example load test data frame and try test.merged<-merge(test, test) or test.merged<-join(test, test, type="all") - The following post provides a list of merge and alternatives: How to join data frames in R (inner, outer, left, right)? The following allows object size inspection: https://heuristically.wordpress.com/2010/01/04/r-memory-usage-statistics-variable/ Data produced by anonym

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  • find the top K most frequent numbers in a data stream

    - by Jin
    This is more of a data structure question rather than a coding question. If I am fetching a data stream, i.e, I keep receiving float numbers once at a time, how should I keep track of the top K frequent numbers? Here my memory is 4G and I prefer to have less communication with hard drive unless necessary. I think heap is good for updating the max and min. How should I design the data structure? Thanks

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  • Android change context for findViewById to super from inline class

    - by wuntee
    I am trying to get the value of a EditText in a dialog box. A the "*"'ed line in the following code, the safeNameEditText is null; i am assuming because the 'findVeiwById' is searching on the context of the 'AlertDialog.OnClickListener'; How can I get/change the context of that 'findViewById' call? protected Dialog onCreateDialog(int id) { AlertDialog.Builder builder = new AlertDialog.Builder(this); switch(id){ case DIALOG_NEW_SAFE: builder.setTitle(R.string.news_safe); builder.setIcon(android.R.drawable.ic_menu_add); LayoutInflater factory = LayoutInflater.from(this); View newSafeView = factory.inflate(R.layout.newsafe, null); builder.setView(newSafeView); builder.setPositiveButton(R.string.ok, new AlertDialog.OnClickListener(){ public void onClick(DialogInterface dialog, int which) { * EditText safeNameEditText = (EditText) findViewById(R.id.new_safe_name); String safeName = safeNameEditText.getText().toString(); Log.i(LOG, safeName); setSafeDao(safeName); } }); builder.setNegativeButton(R.string.cancel, new AlertDialog.OnClickListener(){ public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); return(builder.create()); default: return(null); } }

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  • How to obtain a random sub-datatable from another data table

    - by developerit
    Introduction In this article, I’ll show how to get a random subset of data from a DataTable. This is useful when you already have queries that are filtered correctly but returns all the rows. Analysis I came across this situation when I wanted to display a random tag cloud. I already had the query to get the keywords ordered by number of clicks and I wanted to created a tag cloud. Tags that are the most popular should have more chance to get picked and should be displayed larger than less popular ones. Implementation In this code snippet, there is everything you need. ' Min size, in pixel for the tag Private Const MIN_FONT_SIZE As Integer = 9 ' Max size, in pixel for the tag Private Const MAX_FONT_SIZE As Integer = 14 ' Basic function that retreives Tags from a DataBase Public Shared Function GetTags() As MediasTagsDataTable ' Simple call to the TableAdapter, to get the Tags ordered by number of clicks Dim dt As MediasTagsDataTable = taMediasTags.GetDataValide ' If the query returned no result, return an empty DataTable If dt Is Nothing OrElse dt.Rows.Count < 1 Then Return New MediasTagsDataTable End If ' Set the font-size of the group of data ' We are dividing our results into sub set, according to their number of clicks ' Example: 10 results -> [0,2] will get font size 9, [3,5] will get font size 10, [6,8] wil get 11, ... ' This is the number of elements in one group Dim groupLenth As Integer = CType(Math.Floor(dt.Rows.Count / (MAX_FONT_SIZE - MIN_FONT_SIZE)), Integer) ' Counter of elements in the same group Dim counter As Integer = 0 ' Counter of groups Dim groupCounter As Integer = 0 ' Loop througt the list For Each row As MediasTagsRow In dt ' Set the font-size in a custom column row.c_FontSize = MIN_FONT_SIZE + groupCounter ' Increment the counter counter += 1 ' If the group counter is less than the counter If groupLenth <= counter Then ' Start a new group counter = 0 groupCounter += 1 End If Next ' Return the new DataTable with font-size Return dt End Function ' Function that generate the random sub set Public Shared Function GetRandomSampleTags(ByVal KeyCount As Integer) As MediasTagsDataTable ' Get the data Dim dt As MediasTagsDataTable = GetTags() ' Create a new DataTable that will contains the random set Dim rep As MediasTagsDataTable = New MediasTagsDataTable ' Count the number of row in the new DataTable Dim count As Integer = 0 ' Random number generator Dim rand As New Random() While count < KeyCount Randomize() ' Pick a random row Dim r As Integer = rand.Next(0, dt.Rows.Count - 1) Dim tmpRow As MediasTagsRow = dt(r) ' Import it into the new DataTable rep.ImportRow(tmpRow) ' Remove it from the old one, to be sure not to pick it again dt.Rows.RemoveAt(r) ' Increment the counter count += 1 End While ' Return the new sub set Return rep End Function Pro’s This method is good because it doesn’t require much work to get it work fast. It is a good concept when you are working with small tables, let says less than 100 records. Con’s If you have more than 100 records, out of memory exception may occur since we are coping and duplicating rows. I would consider using a stored procedure instead.

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  • Integrating Data Mining into your BI Solution (Presentation)

    I recently gave a live meeting presentation to the UK User Group on Integrating Data Mining into your BI Solution.  In it I talk about and demo ways of using your data mining models inside Integration Services, Analysis Services and Reporting Services.  This is the first in a series of presentations I will be doing for the UG as I try to get the word out that Data Mining can be for the masses. You can download my deck and my line meeting recording from here.

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  • Inside Sweden’s Nuclear Bunker Turned Data Center

    - by Jason Fitzpatrick
    A data center inside a decommissioned nuclear bunker is interesting enough, but one that looks as futuristic and awesome as the center under Stockholm begs to be seen. A hundred feet under the city of Stockholm is a decommissioned nuclear bunker that the government had previously leased out intermittently for various events, but it was never put to serious or extended use. Not until, that is,  Jon Karlung discovered the location and brought his vision of an ultra-modern, stylish, and secure data center to life. The passage from Wired’s write up of their photo tour that best encapsulates the feel of the bunker is: Most often data centers are built in boxy warehouses, so Bahnhof stands out as perhaps the world’s most stylish. In fact, it inspired Cisco IT Architect Douglas Alger to write a book on the world’s best-looking data centers. ”The idea that people were sitting in a design meeting and said, ‘what we need for our data center is waterfalls,’ that must have been a very fascinating discussion,” Alger says. Hit up the link below for the full photo tour. Deep Inside the James Bond Villain Lair That Actually Exists [Wired] Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder? Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It How To Delete, Move, or Rename Locked Files in Windows

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  • Is there a way to track data structure dependencies from the database, through the tiers, all the way out to a web page?

    - by Sean Mickey
    When we design applications, we generally end up with the same tiered sets of data structures: A persistent data structure that is described using DDL and implemented as RDBMS tables and columns. A set of domain objects that consist primarily of data structures, usually combined with business-rule level logic, that are implemented in a programming language such as Java. A set of service layer interfaces that directly support use case implementations (which use the domain data structures as parameters), implemented as EJBs or something equivalent in another programming language. UI screens that allow users to C reate, R etrieve, U pdate, and (maybe) D elete all manner of data structures and graphs of data structures, with numerous screens and with multiple UI widgets, all structured to support the same data structures. But if you want to change the data structures in any of these tiers, it always seems extremely difficult to assess the impact(s) the change will have across the application. UML can help, but tracing through diagram after diagram is not a real solution to this problem. The best I have ever seen was a homespun data tracking spreadsheet document that listed all of the data structures and walked the relationships from tier-to-tier. Is there a tool or accepted approach that makes it easy to identify a data structure in any tier and easily obtain a list of all dependent: database table and column data structures domain object data structures service layer interface methods and parameter data structures screen & UI component data structures

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  • Dokuwiki: Moving Just the data directory on other server

    - by amit
    I have installed dokuwiki on IIS7. As per my teams requirement we have to move just the Data directory to other server location. e.g - IIS7 installed Dokuwiki location: C:\inetpub\wwwroot\dokuwiki\conf - data location on the other server we want: U:\Archive\LP_Archive\SH_Systems\DEV01\dokuwiki So for doing that I followed pointers on dokuwiki install iis7 As per the above link, I tried adding IUSR to data folder permissions but its failing due to my insufficient privileges. And without that IUSR permission set on data folder I am getting an error as "The datadir ('pages') at is not found, isn't accessible or writable". Is there any other way to make it work? Is there any other account than IUSR I can use?

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  • Big Data Accelerator

    - by Jean-Pierre Dijcks
    For everyone who does not regularly listen to earnings calls, Oracle's Q4 call was interesting (as it mostly is). One of the announcements in the call was the Big Data Accelerator from Oracle (Seeking Alpha link here - slightly tweaked for correctness shown below):  "The big data accelerator includes some of the standard open source software, HDFS, the file system and a number of other pieces, but also some Oracle components that we think can dramatically speed up the entire map-reduce process. And will be particularly attractive to Java programmers [...]. There are some interesting applications they do, ETL is one. Log processing is another. We're going to have a lot of those features, functions and pre-built applications in our big data accelerator."  Not much else we can say right now, more on this (and Big Data in general) at Openworld!

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  • Willy Rotstein on Analytics and Social Media in Retail

    - by sarah.taylor(at)oracle.com
    Recently I came across a presentation from Dan Zarrella on "The Science of Retweets. (http://www.slideshare.net/HubSpot/the-science-of-retweets-with-dan-zarrella). It is an insightful, fact-based analysis of how tweets propagate and what makes them successful. The analysis is of course very interesting for those of us interested Tweeting. However, what really caught my attention is how well it illustrates, form a very different angle, some of the issues I am discussing with retailers these days. In particular the opportunities that e-commerce and social media open to those retailers with the appetite and vision to tackle the associated analytical challenges. And these challenges are of course not straightforward.   In his presentation Dan introduces the concept of Observability, I haven't had the opportunity to discuss with Dan his specific definition for the term. However, in practical retail terms, I would say that it means that through social media (and other web channels such as search) we can analyze and track processes by measuring Indicators that were not measurable before. The focus is in identifying patterns across a large number of consumers rather than what a particular individual "Likes".   The potential impact for retailers is huge. It opens the opportunity to monitor changes in consumer preference  and plan the business accordingly. And you can do this almost "real time" rather than through infrequent surveys that provide a "rear view" picture of your consumer behaviour. For instance, you could envision identifying when a particular set of fashion styles are breaking out from the pack, and commit a re-buy. Or you could monitor when the preference for a specific mobile device has declined and hence markdowns should be considered; or how demand for a specific ready-made food typically flows across regions and manage the inventory accordingly. Search, blogging, website and store data may need to be considered in identifying these trends. The data volumes involved are huge (check Andrea Morgan's recent post on "Big Data" in retail) but so are the benefits. As Andrea says, for the first time we can start getting insight into "Why" the business is performing in a certain way rather than just reporting on what is happening. And it is not just about the data volumes. Tackling the challenge also calls for integrated planning systems that can bring data and insight into the context of the Decision Making process Buyers, Merchandisers and Supply Chain managers are following. I strongly believe that only when data and process come together you can move from the anecdotal to systematically improving business performance.   I would love to hear your opinions on these trends and where you think Retail is heading to exploit these topics - please email me: [email protected]

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  • Extracting data from internet

    - by Ankiov Spetsnaz
    I would like to extract data from internet like www.mozenda.com does but I want to write my own program to do that. Specific data I'm looking for is various event data. Based on my research, I think custom web crawler is my answer but I Would like to confirm the answer and see if there are any suggestion to make custom web crawlers if web crawler indeed is an answer. Personally, I would prefer Java and I'm planning on using Glassfish technology if that matters...

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