Search Results

Search found 67075 results on 2683 pages for 'data model'.

Page 980/2683 | < Previous Page | 976 977 978 979 980 981 982 983 984 985 986 987  | Next Page >

  • Storing multiple discarded datas in a single variable using a string accumulator

    - by dan
    For an assignment for my intro to python course, we are to write a program that generates 100 sets of x,y coordinates. X must be a float between -100.0 and 100.0 inclusive, but not 0. Y is Y = ((1/x) * 3070) but if the absolute value of Y is greater than 100, both numbers must be discarded (BUT STORED) and another set generated. The results must be displayed in a table, and then after the table, the discarded results must be shown. The teacher said we should use a "string accumulator" to store the discarded data. This is what I have so far, and I'm stuck at storing the discarded data. # import random.py import random # import math.py import math # define main def main(): x = random.uniform(-100.0, 100.0) while x == 0: x = random.uniform(-100.0, 100.0) y = ((1/x) * 3070) while math.fabs(y) > 100: xDiscarded = yDiscarded = y = ((1/x) * 3070) As you can see, I run into the problem of when abs(y) 100, I'm not too sure how to store the discarded data and let it accumulate every time abs(y) 100. I'm cool with the data being stored as "351.2, 231.1, 152.2" I just don't know how to turn the variable into a string and store it. We haven't learned arrays yet so I can't do that. Any help would be much appreciated. Thanks!

    Read the article

  • Is it possible to create multi-tiered WHERE statements in mySQL

    - by Brendan
    I'm currently developing a program that will generate reports based upon lead data. My issue is that I'm running 3 queries for something that I would like to only have to run one query for. For instance, I want to gather data for leads generated in the past day submission_date > (NOW() - INTERVAL 1 DAY) and I would like to find out how many total leads there were, and how many sold leads there were in that timeframe. (sold=1 / sold=0). The issue comes with the fact that this query is currently being done with 2 queries, one with WHEREsold= 1 and one with WHEREsold= 0. This is all well and good, but when I want to generate this data for the past day,week,month,year,and all time I will have to run 10 queries to obtain this data. I feel like there HAS to be a more efficient way of doing this. I know I can create a mySQL function for this, but I don't see how this could solve the problem. Thanks!!

    Read the article

  • Mapping element via joining table with NHibernate

    - by NhibernateIdiot
    This is stuff ive done lots of times before but my mind is just blanking at the moment, i will try and give a simple overview of my current situation. I currently have 3 tables as shown below: Office > id, name Person > id, name Office_Personnel > office_id, person_id I then have a model for Person (id, name) and Office, however the Office model contains personnel information: public class Office { int Id {get;set;} string Name {get;set;} ICollection<Person> Personnel {get;set;} } Mapping person is easy, but now im a bit stumped as to why office wont map properly. I chose to use a set when I was mapping the Personnel as there shouldn't be any duplicates, however it doesn't seem to work as I would expect... <set name="Personnel" table="office_personnel" cascade="all"> <key column="office_id" /> <one-to-many class="Person"/> </set> Now one thing that strikes me as odd is that there is no indication as to what person should be binding to (person_id). It keeps trying to find *office_id* column within the Person table. I'm sure this is just some simple problem and im being an idiot, but any help would be great! On a side note, I was weighing up if I should even bother having a middle man table, as I could directly put an Office_Id column within the Person table, but im not 100% sure if in my real project the Person class could be in multiple Offices further down the line...

    Read the article

  • jQuery/Ajax IE7 - Long requests fail

    - by iQ
    Hi guys, I have a problem with IE7 regarding an ajax call that is made by jQuery.load function. Basically the request works in cases where the URL string is not too long, but as soon as the URL gets very large it fails. Doing some debugging on the Ajax call I found this error: URL: <blanked out security reasons but it's very long> Content Type: Headers size (bytes): 0 Data size (bytes): 0 Total size (bytes): 0 Transferred data size (bytes): 0 Cached data: No Error result: 0x800c0005 Error constant: INET_E_RESOURCE_NOT_FOUND Error description: The server or proxy was not found Extended error result: 0x7a Extended error description: The data area passed to a system call is too small. As you can see, it looks like nothing is being sent. Now this only happens on IE7 but not other browsers, with IE8 there is a small delay but still works. The same request works fine when the URL string is relatively small. Now I need this working on IE7 for compatibility reasons and I cannot find workarounds for this so any help is greatly appreciated. The actual ajax call is like this: $("ID").load("url?lotsofparams",callbac func(){}); "lotsofparams" can vary, sometimes being small or very large. It's when the string is very large that I get the above error for IE7 only.

    Read the article

  • Why does my plist file exist even when I've uninstalled an app and wiped the simulator?

    - by just_another_coder
    I am trying to detect the existence of a plist file on application start. When my data class (descendant of NSObject) is initialized, it loads the plist file. Before it loads, it checks to see if the file exists, and if it doesn't, it sets the data = nil instead of trying to process the array of data in the plist file. However, every time it starts it indicates the file exists. Even when I uninstall the app in the organizer and when wiping the simulator directory (iPhone Simulator/3.0/Applications). I have the following static method in a library class named FileIO: +(BOOL) fileExists:(NSString *)fileName { NSString *path = [FileIO getPath:fileName]; // gets the path to the docs directory if ([[NSFileManager defaultManager] fileExistsAtPath:path]) return YES; else return NO; } In my data class: //if( [FileIO fileExists:kFavorites_Filename] ) [FileIO deleteFile:kFavorites_Filename]; if ([FileIO fileExists:kFavorites_Filename]) {NSLog(@"exists"); The "exists" is logged every time unless I un-comment the method to delete the file. How can the file exist if I've deleted the app? I've deleted the simulator directory and uninstalled on the device but both say it still exists. What gives???

    Read the article

  • Cannot serialize this List<T> extension

    - by Jaxidian
    I'm trying to push a subset of a collection of data through WCF to be consumed by WCF - think paged data. As such, I want this collection to have one page's worth of data as well as a total number of results. I figured this should be trivial by creating a custom object that extends List. However, everything I do results in my TotalNumber property coming across as 0. All of the data gets serialized/deserialized just fine but that single integer won't come across at all. Here's my first attempt that failed: [Serializable] public class PartialList<T> : List<T> { public PartialList() { } public PartialList(IEnumerable<T> collection) : base(collection) { } [DataMember] public int UnpartialTotalCount { get; set; } And here's my second attempt that failed in the exact same way: [Serializable] public class PartialList<T> : List<T>, ISerializable { public PartialList() { } public PartialList(IEnumerable<T> collection) : base(collection) { } [DataMember] public int UnpartialTotalCount { get; set; } protected PartialList(SerializationInfo info, StreamingContext context) { UnpartialTotalCount = info.GetInt32("UnpartialTotalCount"); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("UnpartialTotalCount", UnpartialTotalCount); } } What's the deal here??

    Read the article

  • jquery problem in IE working fine in FF

    - by Bharanikumar
    function populate_customer_details(){ $.ajax({ type : 'POST', url : 'populate_customer_details.php', data: { email : $('#txt_email_id').val() }, success : function(data){ if(data=="NOROWSFOUND"){ alert("Sorry, Email ID not exist in our database"); document.getElementById("txt_email_id").focus(); }else{ var val = explode_all_into_arr(data,"|=|"); document.getElementById("FirstName").value = val[0]; document.getElementById("LastName").value = val[1]; document.getElementById("mobilecountrycode").value = parseInt(val[2]); document.getElementById("MobileNo").value = val[3]; document.getElementById("homecountrycode").value = parseInt(val[4]); document.getElementById("HomeNo").value = val[5]; document.getElementById("PaxEmail").value = val[6]; document.getElementById("PaxEmailConf").value = val[6]; } }, }); } This is my snippet purpose is getting the customer details and populate into textfield and combo box , That is Firstname will append into Firstname text field , Secondname will append into Secondname text field , Same like mobilecountrycode (but this is dropdown combo), Some time combo selectedindex work fine, but some time not selecting the value , I am not sure what s problem in that... Nothing works in IE , Also showing object expected error in IE , i have ajax_common.js : in this i added above script , in the page top first i included the jquery.js , Then i include ajax_common.js file, But no idea why this problem. Regards (NOTE i included the jquery.js ) ,

    Read the article

  • Performance Problems with Django's F() Object

    - by JayhawksFan93
    Has anyone else noticed performance issues using Django's F() object? I am running Windows XP SP3 and developing against the Django trunk. A snippet of the models I'm using and the query I'm building are below. When I have the F() object in place, each call to a QuerySet method (e.g. filter, exclude, order_by, distinct, etc.) takes approximately 2 seconds, but when I comment out the F() clause the calls are sub-second. I had a co-worker test it on his Ubuntu machine, and he is not experiencing the same performance issues I am with the F() clause. Anyone else seeing this behavior? class Move (models.Model): state_meaning = models.CharField( max_length=16, db_index=True, blank=True, default='' ) drop = models.ForeignKey( Org, db_index=True, null=False, default=1, related_name='as_move_drop' ) class Split(models.Model): state_meaning = models.CharField( max_length=16, db_index=True, blank=True, default='' ) move = models.ForeignKey( Move, related_name='splits' ) pickup = models.ForeignKey( Org, db_index=True, null=False, default=1, related_name='as_split_pickup' ) pickup_date = models.DateField( null=True, default=None ) drop = models.ForeignKey( Org, db_index=True, null=False, default=1, related_name='as_split_drop' ) drop_date = models.DateField( null=True, default=None, db_index=True ) def get_splits(begin_date, end_date): qs = Split.objects \ .filter(state_meaning__in=['INPROGRESS','FULFILLED'], drop=F('move__drop'), # <<< the line in question pickup_date__lte=end_date) elapsed = timer.clock() - start print 'qs1 took %.3f' % elapsed start = timer.clock() qs = qs.filter(Q(drop_date__gte=begin_date) | Q(drop_date__isnull=True)) elapsed = timer.clock() - start print 'qs2 took %.3f' % elapsed start = timer.clock() qs = qs.exclude(move__state_meaning='UNFULFILLED') elapsed = timer.clock() - start print 'qs3 took %.3f' % elapsed start = timer.clock() qs = qs.order_by('pickup_date', 'drop_date') elapsed = timer.clock() - start print 'qs7 took %.3f' % elapsed start = timer.clock() qs = qs.distinct() elapsed = timer.clock() - start print 'qs8 took %.3f' % elapsed

    Read the article

  • Any workarounds for non-static member array initialization?

    - by TomiJ
    In C++, it's not possible to initialize array members in the initialization list, thus member objects should have default constructors and they should be properly initialized in the constructor. Is there any (reasonable) workaround for this apart from not using arrays? [Anything that can be initialized using only the initialization list is in our application far preferable to using the constructor, as that data can be allocated and initialized by the compiler and linker, and every CPU clock cycle counts, even before main. However, it is not always possible to have a default constructor for every class, and besides, reinitializing the data again in the constructor rather defeats the purpose anyway.] E.g. I'd like to have something like this (but this one doesn't work): class OtherClass { private: int data; public: OtherClass(int i) : data(i) {}; // No default constructor! }; class Foo { private: OtherClass inst[3]; // Array size fixed and known ahead of time. public: Foo(...) : inst[0](0), inst[1](1), inst[2](2) {}; }; The only workaround I'm aware of is the non-array one: class Foo { private: OtherClass inst0; OtherClass inst1; OtherClass inst2; OtherClass *inst[3]; public: Foo(...) : inst0(0), inst1(1), inst2(2) { inst[0]=&inst0; inst[1]=&inst1; inst[2]=&inst2; }; }; Edit: It should be stressed that OtherClass has no default constructor, and that it is very desirable to have the linker be able to allocate any memory needed (one or more static instances of Foo will be created), using the heap is essentially verboten. I've updated the examples above to highlight the first point.

    Read the article

  • Codeigniter: validation problem

    - by krike
    For some reason a user can login with any password, first I thought I forgot to check for the password but I didn't... and I just cant find the problem here is the model: /*#######################################################*/ function validate() /*#######################################################*/ { $this->db->where('username', $this->input->post('username')); $this->db->where('password', md5($this->input->post('password'))); $q = $this->db->get('user_extra'); if($q->num_rows() == 1): return true; else: return false; endif; }//end of function validate() The controller /*#######################################################*/ function validate_credentials() /*#######################################################*/ { $this->load->model('membership_model'); $this->load->library('form_validation'); $this->form_validation->set_rules('username', 'Name', 'trim|required'); $this->form_validation->set_rules('password', 'password', 'trim|required'); if(!$this->membership_model->validate()): $this->form_validation->set_message('check_login', 'Login not correct, please try again.'); endif; if($this->form_validation->run() == FALSE): $this->index(); else: $this->membership_model->userinfo($this->input->post('username')); //should redirect to last view redirect($this->session->flashdata('redirect_url')); endif; }// end of validate_credentials()

    Read the article

  • Rails - Create if record doesn't exist or else update.....Whats Best way to do this?

    - by ChrisWesAllen
    Hi, I have a create statement for some models but its creating a record within a join table regardless if the record exist. Here is what my code looks like. @user = User.find(current_user) @event = Event.find(params[:id]) for interest in @event.interests @user.choices.create(:interest => interest, :score => 4) end The problem is it creates records no matter what. I would like it to create a record if it doesnt exist, if a record does exist I would just to it to take the attribute of the found record and add or subtract 1. So, I've been looking around and I see something called find_or_create_by. My question is what happens if it finds? Preferably if it finds,I would like to take the current :score attribute and +1. SO is it possible to find or create by id? I'm not sure what attribute I would find by since the model I'm looking at is a join model which only had id foreign keys and the score attribute. I tried @user.choices.find_or_create_by_user(:user => @user.id, :interest => interest, :score => 4) but got "undefined method `find_by_user'".....ANy ideas or help?

    Read the article

  • JSF getter methods called BEFORE beforePhase fires

    - by Bill Leeper
    I got a recommendation to put all data lookups in the beforePhase for a given page, however, now that I am doing some deeper analysis it appears that some getter methods are being called before the beforePhase is fired. It became very obvious when I added support for a url parameter and I was getting NPEs on objects that are initialized in the beforePhase call. Any thoughts? Something I have set wrong. I have this in my JSP page: <f:view beforePhase="#{someController.beforePhaseSummary}"> That is only the 5th line in the JSP file and is right after the taglibs. Here is the code that is in the beforePhaseSummary method: public void beforePhaseSummary(PhaseEvent event) { logger.debug("Fired Before Phase Summary: " + event.getPhaseId()); if (event.getPhaseId() == PhaseId.RENDER_RESPONSE) { HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest(); if (request.getParameter("application_id") != null) { loadApplication(Long.parseLong(request.getParameter("application_id"))); } /* Do data fetches here */ } } The logging output above indicates that an event is fired. The servlet request is used to capture the url parameters. The data fetches gather data. However, the logging output is below: 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 107 - Getting UnsubmittedCount 2010-04-23 13:44:46,984 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:47,031 [http-8080-4] DEBUG ...SomeController 133 - Fired Before Phase Summary: RENDER_RESPONSE(6) The logs indicate 2 calls to the getPermit method and one to getUnsubmittedCount before the beforePhase is fired.

    Read the article

  • posting form with file upload

    - by Jan
    I am having trouble with uploading a file when using jquery. I have the following HTML in a form. <fieldset> <ul> <li> <div class="field"><input size="35" type="file" name="formFile" id="formFile"/></div> </li> <li> <div class="field"><input size="35" type="text" name="formFileName" id="formFileName" /></div> </li> </ul> </fieldset> To post the data I am using $('#myForm').ajaxForm( When I post the data and the recieved data contains some javascript, the javascript is not recognised. I expected the javscriptcode to run when the data is recieved, but it happens to early. The results indicates that $ or jquery could not be found. If I remove the name attribute from the input type=file element, there are no errors, but that is not the correct solution. How could this happen?

    Read the article

  • Using classes for the first time,help in debugging

    - by kaushik
    here is post my code:this is no the entire code but enough to explain my doubt.please discard any code line which u find irrelavent enter code here saving_tree={} isLeaf=False class tree: global saving_tree rootNode=None lispTree=None def __init__(self,x): file=x string=file.readlines() #print string self.lispTree=S_expression(string) self.rootNode=BinaryDecisionNode(0,'Root',self.lispTree) class BinaryDecisionNode: global saving_tree def __init__(self,ind,name,lispTree,parent=None): self.parent=parent nodes=lispTree.getNodes(ind) print nodes self.isLeaf=(nodes[0]==1) nodes=nodes[1]#Nodes are stored self.name=name self.children=[] if self.isLeaf: #Leaf Node print nodes #Set the leaf data self.attribute=nodes print "LeafNode is ",nodes else: #Set the question self.attribute=lispTree.getString(nodes[0]) self.attribute=self.attribute.split() print "Question: ",self.attribute,self.name tree={} tree={str(self.name):self.attribute} saving_tree=tree #Add the children for i in range(1,len(nodes)):#Since node 0 is a question # print "Adding child ",nodes[i]," who has ",len(nodes)-1," siblings" self.children.append(BinaryDecisionNode(nodes[i],self.name+str(i),lispTree,self)) print saving_tree i wanted to save some data in saving_tree{},which i have declared previously and want to use that saving tree in the another function outside the class.when i asked to print saving_tree it printing but,only for that instance.i want the saving_tree{} to have the data to store data of all instance and access it outside. when i asked for print saving_tree outside the class it prints empty{}.. please tell me the required modification to get my required output and use saving_tree{} outside the class..

    Read the article

  • CakePHP 2.0: how to access properties of the parent object?

    - by PaulJ
    I just started learning CakePHP 2.0 a few days ago, and there's one thing that is leaving me stumped: say I have an User model and a Posts model: class User extends AppModel { public $name = "User"; public $hasMany=array( 'Post' => array( 'className' => 'Post', 'foreignKey' => 'author_id' ) ); } class Post extends AppModel { public $name = 'Post'; public $belongsTo = array( 'className' = 'User', 'foreignKey' = 'author_id', ); } (Where "author_id" is the foreign key in the posts table that references the Users table's primary key). And now, in the PostsController, I want to access the properties of the user that owns the current post (to show his display name, for example). What would be the proper syntax? I tried: $this->Post->User->find('first', array('conditions' => array('User.id' => "$usuario"))) But it didn't work (I guess it's because the User is the parent of the Post object, not its child). Or should CakePHP load everything automatically, once you've declared the $hasMany and $belongsTo relationships?

    Read the article

  • Basic Application Organization + Publishing (.NET 4.0)

    - by keynesiancross
    Hi all, I'm trying to figure out the best way to keep my program organized. Currently I have many class files in one project file, but some of these classes do things that are very different, and some I would like to expose to other applications in the future. One thought I had to organizing my application was to create multiple project files, with one "Main" project, which would interact with all the other projects and their relevant classes as needed. Does this make sense? I was wondering if anyone had any suggestions in regards to using multiple project files in one solution (and how do you create something like this?), and if it makes sense to have multiple namespaces in one solution... Cheers ----Edit Below---- Sorry, my fault. Currently my program is all in one console project. Within this project I have several classes, some of which basically launch a BackgroundWorker and run an endless loop pulling data. The BackgroundWorker then passes this data back to the main business logic as needed. I'm hoping to seperate this data pull material (including the background worker material) into one project file, and the rest of the business logic into another project file. The projects will have to pass objects between eachother though (the data to the main business logic, and the business logic will pass startup parameteres to the dataPull project)... Hopefully this adds a bit more detail.

    Read the article

  • Beginner having difficulty with SQL query

    - by Vulcanizer
    Hi, I've been studying SQL for 2 weeks now and I'm preparing for an SQL test. Anyway I'm trying to do this question: For the table: 1 create table data { 2 id int, 3 n1 int not null, 4 n2 int not null, 5 n3 int not null, 6 n4 int not null, 7 primary key (id) 8 } I need to return the relation with tuples (n1, n2, n3) where all the corresponding values for n4 are 0. The problem asks me to solve it WITHOUT using subqueries(nested selects/views) It also gives me an example table and the expected output from my query: 01 insert into data (id, n1, n2, n3, n4) 02 values (1, 2,4,7,0), 03 (2, 2,4,7,0), 04 (3, 3,6,9,8), 05 (4, 1,1,2,1), 06 (5, 1,1,2,0), 07 (6, 1,1,2,0), 08 (7, 5,3,8,0), 09 (8, 5,3,8,0), 10 (9, 5,3,8,0); expects (2,4,7) (5,3,8) and not (1,1,2) since that has a 1 in n4 in one of the cases. The best I could come up with was: 1 SELECT DISTINCT n1, n2, n3 2 FROM data a, data b 3 WHERE a.ID <> b.ID 4 AND a.n1 = b.n1 5 AND a.n2 = b.n2 6 AND a.n3 = b.n3 7 AND a.n4 = b.n4 8 AND a.n4 = 0 but I found out that also prints (1,1,2) since in the example (1,1,2,0) happens twice from IDs 5 and 6. Any suggestions would be really appreciated.

    Read the article

  • Using multiple Qt (SQL) Models

    - by radix07
    I have a near real-time application that I am using Qt and an SQLite database to run. I am curious if it is safe to have two separate models access a database at once. I know 2 separate views can access a model just fine, but I can't find any document addressing this. I also realize that SQLite is thread safe for reading, so I don't see a real issue to doing this from the SQLite part of things... Basically I want to use a QSqlTableModel to do the real-time read and write in the background and at the same time use a QSqlQueryModel to give the user desired data. Since I may be doing lots of filtering in the background using the table model I can't use it as the main view as well. I have gotten this to work for the most part, but am not sure if this is the best way to do this. If the models act like multiple SQL queries I don't believe this should be an issue, but I would like to know from someone I bit more knowledgeable about this stuff since this is pretty new to me. Thanks

    Read the article

  • Database solution for 200million writes/day, monthly summarization queries

    - by sb
    Hello. I'm looking for help deciding on which database system to use. (I've been googling and reading for the past few hours; it now seems worthwhile to ask for help from someone with firsthand knowledge.) I need to log around 200 million rows (or more) per 8 hour workday to a database, then perform weekly/monthly/yearly summary queries on that data. The summary queries would be for collecting data for things like billing statements, eg. "How many transactions of type A did each user run this month?" (could be more complex, but that's the general idea). I can spread the database amongst several machines, as necessary, but I don't think I can take old data offline. I'll definitely need to be able to query a month's worth of data, maybe a year. These queries would be for my own use, and wouldn't need to be generated in real-time for an end-user (they could run overnight, if needed). Does anyone have any suggestions as to which databases would be a good fit? P.S. Cassandra looks like it would have no problem handling the writes, but what about the huge monthly table scans? Is anyone familiar with Cassandra/Hadoop MapReduce performance?

    Read the article

  • Rails dealing with blank params at controller level

    - by stephenmurdoch
    I have a User model: class User < ActiveRecord::Base has_secure_password # validation lets users update accounts without entering password validates :password, presence: { on: :create }, allow_blank: { on: :update } validates :password_confirmation, presence: { if: :password_digest_changed? } end I also have a password_reset_controller: def update # this is emailed to the user by the create action - not shown @user=User.find_by_password_reset_token!(params[:id]) if @user.update_attributes(params[:user]) # user is signed in if password and confirmation pass validations sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Can you see the problem here? A user can submit a blank a password/confirmation and rails will sign them in, because the User model allows blank on update. It's not a security concern, since an attacker would still need access to a user's email account before they could get anywhere near this action, but my problem is that a user submitting 6 blank chars would be signed in, and their password would not be changed for them, which could lead to confusion later on. So, I've come up with the following solution, and I'd like to check if there's a better way of doing it, before I push to production: def update @user=User.find_by_password_reset_token!(params[:id]) # if user submits blank password, add an error, and render edit action if params[:user][:password].blank? @user.errors.add(:password_digest, "can't be blank.") render :edit elsif @user.update_attributes(params[:user]) sign_in @user redirect_to root_url, :notice => "Password has been reset." else flash.now[:error] = "Something went wrong, please try again." render :edit end end Should I be checking for nil as well as blank? Are there any rails patterns or idiomatic ruby techniques for solving this? [Fwiw, I've got required: true on the html inputs, but want this handled server side too.]

    Read the article

  • Java: Cleaing up connection reset (but not by peer).

    - by Zombies
    There seems to be some confusion as well contradicting statements on various SO answers: http://stackoverflow.com/questions/585599/whats-causing-my-java-net-socketexception-connection-reset . You can see here that the accepted answer states that the connecteion was closed by other side. But this is not true, closing a connection doesn't cause a connection reset. It is cauesed by "an underlying TCP/IP error." What I want to know is if a SocketException: Connection reset means really besides "unerlying TCP/IP Error." What really causes this? As I doubt it has anything to do with the connection being closed (since closing a connection isn't an exception worthy flag, and reading from a closed connection is, but that isn't an "underlying TCP/IP error." My hypothesis is this Connection reset is caused from a server's failure to acknowledge an ACK packet (either wholly or just improperly as per TCP/IP). And that a SocketTimeoutException is generated only when no data is generated to be read (since this is thrown during a read after a certain duration, and read is waiting for data, but is not concerned with ACK packets). In other words, read() throws SocketTimeoutException if it didn't read any bytes of actual data (DATA LAYER) in its allotted time.

    Read the article

  • How to read/write from erlang to a named pipe ?

    - by cstar
    I need my erlang application to read and write through a named pipe. Opening the named pipe as a file will fail with eisdir. I wrote the following module, but it is fragile and feels wrong in many ways. Also it fails on reading after a while. Is there a way to make it more ... elegant ? -module(port_forwarder). -export([start/2, forwarder/2]). -include("logger.hrl"). start(From, To)-> spawn(fun() -> forwarder(From, To) end). forwarder(FromFile, ToFile) -> To = open_port({spawn,"/bin/cat > " ++ ToFifo}, [binary, out, eof,{packet, 4}]), From = open_port({spawn,"/bin/cat " ++ FromFifo}, [binary, in, eof, {packet, 4}]), forwarder(From, To, nil). forwarder(From, To, Pid) -> receive {Manager, {command, Bin}} -> ?ERROR("Sending : ~p", [Bin]), To ! {self(), {command, Bin}}, forwarder(From, To, Manager); {From ,{data,Data}} -> Pid ! {self(), {data, Data}}, forwarder(From, To, Pid); E -> ?ERROR("Quitting, first message not understood : ~p", [E]) end. As you may have noticed, it's mimicking the port format in what it accepts or returns. I want it to replace a C code that will be reading the other ends of the pipes and being launched from the debugger.

    Read the article

  • Confused about std::runtime_error vs. std::logic_error

    - by David Gladfelter
    I recently saw that the boost program_options library throws a logic_error if the command-line input was un-parsable. That challenged my assumptions about logic_error vs. runtime_error. I assumed that logic errors (logic_error and its derived classes) were problems that resulted from internal failures to adhere to program invariants, often in the form of illegal arguments to internal API's. In that sense they are largely equivalent to ASSERT's, but meant to be used in released code (unlike ASSERT's which are not usually compiled into released code.) They are useful in situations where it is infeasible to integrate separate software components in debug/test builds or the consequences of a failure are such that it is important to give runtime feedback about the invalid invariant condition to the user. Similarly, I thought that runtime_errors resulted exclusively from runtime conditions outside of the control of the programmer: I/O errors, invalid user input, etc. However, program_options is obviously heavily (primarily?) used as a means of parsing end-user input, so under my mental model it certainly should throw a runtime_error in the case of bad input. Where am I going wrong? Do you agree with the boost model of exception typing?

    Read the article

  • I have a slight confusion with setting up Mercurial on my webserver...

    - by littlejim84
    I'm starting to use Mercurial on my web server (in this case MediaTemple's Grid). I've used SVN previously, though I'm not an expert of version control systems. I'm just needing a little help with clearing up some confusion with getting it set up optimally. I have a 'data' folder which is outside the web server root and that the browser cannot access. It was recommended to me before to have my Mercurial repositories setup here, then I would clone from here locally on my computer. I would also have a 'domains' folder that is basically the web server root and inside there is my actual domains where my websites are actually served to the browser - these would need to be updated from the 'data' repositories too. But with this in mind, after setting it up, it seems inefficient... I'm cloning to my local (that makes sense), adding, committing, pushing. That's fine... But then I'm then updating in my data repository folder and then updating in my domains folder to actually update my websites. Surely, I don't actually need this 'data' folder for repositories? Wouldn't my actual live 'domains' folders be the main repositories themselves? So I'm cloning locally and updating from these? Please help me clear some confusions with all this (if you can).

    Read the article

  • How to calculate how many lines (or records) can fit in the given page size

    - by devcoder
    My problem is to calculate the data (string) that can fit into the given page size (in inches). I have an application which creates plain vanilla HTML report without using any reporting controls. Now I have to provide paging support in this report. the report is dynamic in nature i.e. columns are decided at run time. Depending upon the page width, I want to wrap columns in multiple lines. For example, if the page width is 8", i want to fit only first 'n' columns in first line and rest columns can be displayed in second line (or more lines if required). For this I need to calculate how much data can fit in a 8" wide line. Similarly, I want to calculate the height of data that can fit into the given height of page. To summarize, how can I calculate how much data can fit into the given page size in inches. Note: The calculation should also consider the font as it is decided at run time.

    Read the article

< Previous Page | 976 977 978 979 980 981 982 983 984 985 986 987  | Next Page >