Search Results

Search found 1112 results on 45 pages for 'constraints'.

Page 41/45 | < Previous Page | 37 38 39 40 41 42 43 44 45  | Next Page >

• ASP.Net Web Farm Monitoring

  - by cisellis

  I am looking for suggestions on doing some simple monitoring of an ASP.Net web farm as close to real-time as possible. The objectives of this question are to: Identify the best way to monitor several Windows Server production boxes during short (minutes long) period of ridiculous load Receive near-real-time feedback on a few key metrics about each box. These are simple metrics available via WMI such as CPU, Memory and Disk Paging. I am defining my time constraints as soon as possible with 120 seconds delayed being the absolute upper limit. Monitor whether any given box is up (with "up" being defined as responding web requests in a reasonable amount of time) Here are more details, things I've tried, etc. I am not interested in logging. We have logging solutions in place. I have looked at solutions such as ELMAH which don't provide much in the way of hardware monitoring and are not visible across an entire web farm. ASP.Net Health Monitoring is too broad, focuses too much on logging and is not acceptable for deep analysis. We are on Amazon Web Services and we have looked into CloudWatch. It looks great but messages in the forum indicate that the metrics are often a few minutes behind, with one thread citing 2 minutes as the absolute soonest you could expect to receive the feedback. This would be good to have for later analysis but does not help us real-time Stuff like JetBrains profiler is good for testing but again, not helpful during real-time monitoring. The closest out-of-box solution I've seen is Nagios which is free and appears to measure key indicators on any kind of box, including Windows. However, it appears to require a Linux box to run itself on and a good deal of manual configuration. I'd prefer to not spend my time mining config files and then be up a creek when it fails in production since Linux is not my main (or even secondary) environment. Are there any out-of-box solutions that I am missing? Obviously a windows-based solution that is easy to setup is ideal. I don't require many bells and whistles. In the absence of an out-of-box solution, it seems easy for me to write something simple to handle what I need. I've been thinking a simple client-server setup where the server requests a few WMI metrics from each client over http and sticks them in a database. We could then monitor the metrics via a query or a dashboard or something. If the client doesn't respond, it's effectively down. Any problems with this, best practices, or other ideas? Thanks for any help/feedback.

  Read the article

• Is there an algorithm for converting quaternion rotations to Euler angle rotations?

  - by Will Baker

  Is there an existing algorithm for converting a quaternion representation of a rotation to an Euler angle representation? The rotation order for the Euler representation is known and can be any of the six permutations (i.e. xyz, xzy, yxz, yzx, zxy, zyx). I've seen algorithms for a fixed rotation order (usually the NASA heading, bank, roll convention) but not for arbitrary rotation order. Furthermore, because there are multiple Euler angle representations of a single orientation, this result is going to be ambiguous. This is acceptable (because the orientation is still valid, it just may not be the one the user is expecting to see), however it would be even better if there was an algorithm which took rotation limits (i.e. the number of degrees of freedom and the limits on each degree of freedom) into account and yielded the 'most sensible' Euler representation given those constraints. I have a feeling this problem (or something similar) may exist in the IK or rigid body dynamics domains. Solved: I just realised that it might not be clear that I solved this problem by following Ken Shoemake's algorithms from Graphics Gems. I did answer my own question at the time, but it occurs to me it may not be clear that I did so. See the answer, below, for more detail. Just to clarify - I know how to convert from a quaternion to the so-called 'Tait-Bryan' representation - what I was calling the 'NASA' convention. This is a rotation order (assuming the convention that the 'Z' axis is up) of zxy. I need an algorithm for all rotation orders. Possibly the solution, then, is to take the zxy order conversion and derive from it five other conversions for the other rotation orders. I guess I was hoping there was a more 'overarching' solution. In any case, I am surprised that I haven't been able to find existing solutions out there. In addition, and this perhaps should be a separate question altogether, any conversion (assuming a known rotation order, of course) is going to select one Euler representation, but there are in fact many. For example, given a rotation order of yxz, the two representations (0,0,180) and (180,180,0) are equivalent (and would yield the same quaternion). Is there a way to constrain the solution using limits on the degrees of freedom? Like you do in IK and rigid body dynamics? i.e. in the example above if there were only one degree of freedom about the Z axis then the second representation can be disregarded. I have tracked down one paper which could be an algorithm in this pdf but I must confess I find the logic and math a little hard to follow. Surely there are other solutions out there? Is arbitrary rotation order really so rare? Surely every major 3D package that allows skeletal animation together with quaternion interpolation (i.e. Maya, Max, Blender, etc) must have solved exactly this problem?

  Read the article

• In Protobuf-net how can I pass an array of type object with objects of different types inside, knowi

  - by cloudraven

  I am trying to migrate existing code that uses XmlSerializer to protobuf-net due to the increased performance it offers, however I am having problems with this specific case. I have an object[] that includes parameters that are going to be sent to a remote host (sort of a custom mini rpc facility). I know the set of types from which these parameters can be, but I cannot tell in advance in which order they are going to be sent. I have three constraints. The first is that I am running in Compact Framework, so I need something that works there. Second, as I mentioned performance is a big concern (on the serializing side) so I would rather avoid using a lot of reflection there if possible. And the most important is that I care about the order in which this parameters were sent. Using XmlSerializer it was easy just adding XmlInclude, but for fields there is nothing equivalent as far as I know in Protobuf-net. So, is there a way to do this? Here is a simplified example. [Serializable] [XmlInclude(typeof(MyType1)), XmlInclude(typeof(MyType2)), XmlInclude(typeof(MyType3)) public class Message() { public object[] parameters; public Message(object[] parms) { parameters = parms; } } Message m = new Message(new object[] {MyType1(), 33, "test", new MyType3(), new MyType3()}); MemoryStream ms = new MemoryStream(); XmlSerializer xml = new XmlSerializer(typeof(Message)); xml.Serialize(ms,xml); That will just work with XmlSerializer, but if I try to convert it to protobuf-net I will get a "No default encoding for Object" message. The best I came up with is to use generics and [ProtoInclude] as seen in this example. Since I can have different object types within the array this doesn't quite make it. I added a generic List for each potential type and a property with [ProtoIgnore] with type object[] to add them and get them. I have to use reflection when adding them (to know in which array to put each item) which is not desirable and I still can't preserve the ordering as I just extract all the items on each list one by one and put them into a new object[] array on the property get. I wonder if there is a way to accomplish this?

  Read the article

• Finding minimum cut-sets between bounded subgraphs

  - by Tore

  If a game map is partitioned into subgraphs, how to minimize edges between subgraphs? I have a problem, Im trying to make A* searches through a grid based game like pacman or sokoban, but i need to find "enclosures". What do i mean by enclosures? subgraphs with as few cut edges as possible given a maximum size and minimum size for number of vertices for each subgraph that act as a soft constraints. Alternatively you could say i am looking to find bridges between subgraphs, but its generally the same problem. Given a game that looks like this, what i want to do is find enclosures so that i can properly find entrances to them and thus get a good heuristic for reaching vertices inside these enclosures. So what i want is to find these colored regions on any given map. My Motivation The reason for me bothering to do this and not just staying content with the performance of a simple manhattan distance heuristic is that an enclosure heuristic can give more optimal results and i would not have to actually do the A* to get some proper distance calculations and also for later adding competitive blocking of opponents within these enclosures when playing sokoban type games. Also the enclosure heuristic can be used for a minimax approach to finding goal vertices more properly. A possible solution to the problem is the Kernighan-Lin algorithm: function Kernighan-Lin(G(V,E)): determine a balanced initial partition of the nodes into sets A and B do A1 := A; B1 := B compute D values for all a in A1 and b in B1 for (i := 1 to |V|/2) find a[i] from A1 and b[i] from B1, such that g[i] = D[a[i]] + D[b[i]] - 2*c[a][b] is maximal move a[i] to B1 and b[i] to A1 remove a[i] and b[i] from further consideration in this pass update D values for the elements of A1 = A1 / a[i] and B1 = B1 / b[i] end for find k which maximizes g_max, the sum of g[1],...,g[k] if (g_max > 0) then Exchange a[1],a[2],...,a[k] with b[1],b[2],...,b[k] until (g_max <= 0) return G(V,E) My problem with this algorithm is its runtime at O(n^2 * lg(n)), i am thinking of limiting the nodes in A1 and B1 to the border of each subgraph to reduce the amount of work done. I also dont understand the c[a][b] cost in the algorithm, if a and b do not have an edge between them is the cost assumed to be 0 or infinity, or should i create an edge based on some heuristic. Do you know what c[a][b] is supposed to be when there is no edge between a and b? Do you think my problem is suitable to use a multi level problem? Why or why not? Do you have a good idea for how to reduce the work done with the kernighan-lin algorithm for my problem?

  Read the article

• Maven best practice for generating multiple jars with different/filtered classes ?

  - by jaguard

  I developed a Java utility library (similarly to Apache Commons) that I use in various projects. Additionally to fat clients I also use it for mobile clients (PDA with J9 Foundation profile). In time the library that started as a single project spread over multiple packages. As a result I end up with a lot of functionality but not really needed in all the projects. Since this library is also used inside some mobile/PDA projects I need a way to collect just the used classes and generate the actual specialized jars Currently in the projects that area using this library, I have Ant jar tasks that generate (from the utility project) the specialized jar files (ex: my-util-1.0-pda.jar, my-util-1.0-rcp.jar) using include/exclude jar task features. This is mostly needed due to the generated jar size constraints for the mobile projects. Migrating now to Maven I just wonder if there are any best practices to arrive to something similar so I consider the following scenarios: [1] - additionally to the main jar artifact (my-lib-1.0.jar) also generating inside my-lib project the separate/specialized artifacts using classifiers (ex: my-lib-1.0-pda.jar) using Maven Jar Plugin or Maven Assembly Plugin filtering/includes ... I'm not very comfortable with this approach since it pollute the library with library consumers demands (filters) [2] - Create additional Maven projects for all the specialized clients/projects, that will "wrap" the "my-lib" and generate the filtered jar artifacts (ex: my-lib-wrapper-pda-1.0 ...etc). As a result, these wrapper projects will include the filtering (to generate the filtered artifact) and will depend just on the "my-lib" project and the client projects will depend on my-lib-wrapper-xxx-1.0 instead of my-lib-1.0. This approach my look problematic since even that will let "my-lib" project intact (with no additional classifiers & artifacts), basically will double the number of projects since for every client project I'll have one just to collect the needed classes from the "my-util" library ("my-pda-app" project will need a "my-lib-wrapper-for-my-pda-app" project/dependency) [3] - Into the every client project that use the library (ex: my-pda-app) add some specialized Maven plugins to trim - out (when generating the final artifact/package) the un-needed classes (ex: maven-assembly-plugin, maven-jar-plugin, proguard-maven-plugin) What is the best practice for solving this kind of problems in the "Maven way" ?!

  Read the article

• Oracle sample data problems

  - by Jay

  So, I have this java based data trasformation / masking tool, which I wanted to test out on Oracle 10g. The good part with Oracle 10g is that you get a load of sample schemas with half a million records in some. The schemas are : SH, OE, HR, IX and etc. So, I installed 10g, found out that the installation scripts are under ORACLE_HOME/demo/scripts. I customized these scripts a bit to run in batch mode. That solves one half of my requirement - to create source data for my testing my data transformation software. The second half of the requirement is that I create the same schemas under different names (TR_HR, TR_OE and so on...) without any data. These schemas would represent my target schemas. So, in short, my software would pick up data from a table in a schema and load it up in to the same table in a different schema. Now, I have two issues in creating my target schema and emptying it. I would like this in a batch job. But the oracle scripts you get, the sample schema names are not configurable. So, I tried creating a script, replacing OE with TR_OE, HR with TR_HR and so on. However, this approach is kind of irritating coz the sample schemas are kind of complicated in the way they are created; Oracle creates synonyms, views, materialized views, data types and lot of weird stuff. I would like the target schemas (TR_HR, TR_OE,...) to be empty. But some of the schemas have circular references, which would not allow me to delete data. The only work around seems to be removing certain foreign keys, deleting data and then adding the constraints back. Is there any easy way to all this, without all this fuss? I would need a complicated data set for my testing (complicated as in tables with triggers, multiple hierarchies.. for instance.. a child table that has children up to 5 levels, a parent table that refers to an IOT table and an IOT table that refers to a non-IOT table etc..). The sample schemas are just about perfect from a data set perspective. The only challenge I see is in automating this whole process of loading up the source schemas, and then creating the target schemas and emptying them. Appreciate your help and suggestions.

  Read the article

• Castle ActiveRecord - schema generation without enforcing referential integrity?

  - by Simon

  Hi all, I've just started playing with Castle active record as it seems like a gentle way into NHibernate. I really like the idea of the database schema being generate from my classes during development. I want to do something similar to the following: [ActiveRecord] public class Camera : ActiveRecordBase<Camera> { [PrimaryKey] public int CameraId {get; set;} [Property] public int CamKitId {get; set;} [Property] public string serialNo {get; set;} } [ActiveRecord] public class Tripod : ActiveRecordBase<Tripod> { [PrimaryKey] public int TripodId {get; set;} [Property] public int CamKitId {get; set;} [Property] public string serialNo {get; set;} } [ActiveRecord] public class CameraKit : ActiveRecordBase<CameraKit> { [PrimaryKey] public int CamKitId {get; set;} [Property] public string description {get; set;} [HasMany(Inverse=true, Table="Cameras", ColumnKey="CamKitId")] public IList<Camera> Cameras {get; set;} [HasMany(Inverse=true, Table="Tripods", ColumnKey="CamKitId")] public IList<Camera> Tripods {get; set;} } A camerakit should contain any number of tripods and cameras. Camera kits exist independently of cameras and tripods, but are sometimes related. The problem is, if I use createschema, this will put foreign key constraints on the Camera and Tripod tables. I don't want this, I want to be able to to set CamKitId to null on the tripod and camera tables to indicate that it is not part of a CameraKit. Is there a way to tell activerecord/nhibernate to still see it as related, without enforcing the integrity? I was thinking I could have a cameraKit record in there to indicate "no camera kit", but it seems like oeverkill. Or is my schema wrong? Am I doing something I shouldn't with an ORM? (I've not really used ORMs much) Thanks!

  Read the article

• Grails validateable not work for non-persistent domain class

  - by Hoàng Long

  I followed the instruction here: http://www.grails.org/doc/latest/guide/7.%20Validation.html and added into config.groovy: grails.validateable.classes = [liningtest.Warm'] Then added in src/groovy/Warm.groovy (it's a non-persistent domain class): package liningtest import org.codehaus.groovy.grails.validation.Validateable class Warm { String name; int happyCite; Warm(String n, int h) { this.name = n; this.happyCite = h; } static constraints = { name(size: 1..50) happyCite(min: 100) } } But it just doesn't work (both "blank false" & "size: 0..25") for the "hasErrors" function. It always returns false, even when the name is 25. Is this a Grails bug, if yes, is there any work-around? I'm using Grails 1.3.3 UPDATE: I have updated the simplified code. And now I know that constraint "size" can't be used with "blank", but still does not work. My test class in test/unit/liningtest/WarmTests.groovy package liningtest import grails.test.* class WarmTests extends GrailsUnitTestCase { protected void setUp() { super.setUp() } protected void tearDown() { super.tearDown() } void testSomething() { def w = new Warm('Hihi', 3) assert (w.happyCite == 3) assert (w.hasErrors() == true) } } And the error I got: <?xml version="1.0" encoding="UTF-8" ?> <testsuite errors="1" failures="0" hostname="evolus-50b0002c" name="liningtest.WarmTests" tests="1" time="0.062" timestamp="2010-12-16T04:07:47"> <properties /> <testcase classname="liningtest.WarmTests" name="testSomething" time="0.062"> <error message="No signature of method: liningtest.Warm.hasErrors() is applicable for argument types: () values: [] Possible solutions: hashCode()" type="groovy.lang.MissingMethodException">groovy.lang.MissingMethodException: No signature of method: liningtest.Warm.hasErrors() is applicable for argument types: () values: [] Possible solutions: hashCode() at liningtest.WarmTests.testSomething(WarmTests.groovy:18) </error> </testcase> <system-out><![CDATA[--Output from testSomething-- ]]></system-out> <system-err><![CDATA[--Output from testSomething-- ]]></system-err> </testsuite> UPDATE 2: When I don't use Unit test, but try to call hasErrors in the controller, it runs but return false value. (hasErrors return false with Warm('Hihi', 3) ). Does anyone has a clue?

  Read the article

• Complex relationship between tables in NHibernate

  - by Ilya Kogan

  Hi all, I'm writing a Fluent NHibernate mapping for a legacy Oracle database. The challenge is that the tables have composite primary keys. If I were at total freedom, I would redesign the relationships and auto-generate primary keys, but other applications must write to the same database and read from it, so I cannot do it. These are the two tables I'll focus on: Example data Trips table: 1, 10:00, 11:00 ... 1, 12:00, 15:00 ... 1, 16:00, 19:00 ... 2, 12:00, 13:00 ... 3, 9:00, 18:00 ... Faults table: 1, 13:00 ... 1, 23:00 ... 2, 12:30 ... In this case, vehicle 1 made three trips and has two faults. The first fault happened during the second trip, and the second fault happened while the vehicle was resting. Vehicle 2 had one trip, during which a fault happened. Constraints Trips of the same vehicle never overlap. So the tables have an optional one-to-many relationship, because every fault either happens during a trip or it doesn't. If I wanted to join them in SQL, I would write: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime and then I'd get a dataset where every fault appears exactly once (one-to-many as I said). Note that there is no Vehicles table, and I don't need one. But I did create a view that contains all VehicleIds from both tables, so I can use it as a junction table. What am I actually looking for? The tables are huge because they cover years of data, and every time I only need to fetch a range of a few hours. So I need a mapping and a criteria that will run something like the following SQL underneath: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime where Faults.FaultTime between :p0 and :p1 Do you have any ideas how to achieve it? Note 1: Currently the application shouldn't write to the database, so persistence is not a must, although if the mapping supports persistence, it may help at some point in the future. Note 2: I know it's a tough one, so if you give me a great answer, you will be properly rewarded :) Thank you for reading this long question, and now I only hope for the best :)

  Read the article

• Optimize date query for large child tables: GiST or GIN?

  - by Dave Jarvis

  Problem 72 child tables, each having a year index and a station index, are defined as follows: CREATE TABLE climate.measurement_12_013 ( -- Inherited from table climate.measurement_12_013: id bigint NOT NULL DEFAULT nextval('climate.measurement_id_seq'::regclass), -- Inherited from table climate.measurement_12_013: station_id integer NOT NULL, -- Inherited from table climate.measurement_12_013: taken date NOT NULL, -- Inherited from table climate.measurement_12_013: amount numeric(8,2) NOT NULL, -- Inherited from table climate.measurement_12_013: category_id smallint NOT NULL, -- Inherited from table climate.measurement_12_013: flag character varying(1) NOT NULL DEFAULT ' '::character varying, CONSTRAINT measurement_12_013_category_id_check CHECK (category_id = 7), CONSTRAINT measurement_12_013_taken_check CHECK (date_part('month'::text, taken)::integer = 12) ) INHERITS (climate.measurement) CREATE INDEX measurement_12_013_s_idx ON climate.measurement_12_013 USING btree (station_id); CREATE INDEX measurement_12_013_y_idx ON climate.measurement_12_013 USING btree (date_part('year'::text, taken)); (Foreign key constraints to be added later.) The following query runs abysmally slow due to a full table scan: SELECT count(1) AS measurements, avg(m.amount) AS amount FROM climate.measurement m WHERE m.station_id IN ( SELECT s.id FROM climate.station s, climate.city c WHERE -- For one city ... -- c.id = 5182 AND -- Where stations are within an elevation range ... -- s.elevation BETWEEN 0 AND 3000 AND 6371.009 * SQRT( POW(RADIANS(c.latitude_decimal - s.latitude_decimal), 2) + (COS(RADIANS(c.latitude_decimal + s.latitude_decimal) / 2) * POW(RADIANS(c.longitude_decimal - s.longitude_decimal), 2)) ) <= 50 ) AND -- -- Begin extracting the data from the database. -- -- The data before 1900 is shaky; insufficient after 2009. -- extract( YEAR FROM m.taken ) BETWEEN 1900 AND 2009 AND -- Whittled down by category ... -- m.category_id = 1 AND m.taken BETWEEN -- Start date. (extract( YEAR FROM m.taken )||'-01-01')::date AND -- End date. Calculated by checking to see if the end date wraps -- into the next year. If it does, then add 1 to the current year. -- (cast(extract( YEAR FROM m.taken ) + greatest( -1 * sign( (extract( YEAR FROM m.taken )||'-12-31')::date - (extract( YEAR FROM m.taken )||'-01-01')::date ), 0 ) AS text)||'-12-31')::date GROUP BY extract( YEAR FROM m.taken ) The sluggishness comes from this part of the query: m.taken BETWEEN /* Start date. */ (extract( YEAR FROM m.taken )||'-01-01')::date AND /* End date. Calculated by checking to see if the end date wraps into the next year. If it does, then add 1 to the current year. */ (cast(extract( YEAR FROM m.taken ) + greatest( -1 * sign( (extract( YEAR FROM m.taken )||'-12-31')::date - (extract( YEAR FROM m.taken )||'-01-01')::date ), 0 ) AS text)||'-12-31')::date The HashAggregate from the plan shows a cost of 10006220141.11, which is, I suspect, on the astronomically huge side. There is a full table scan on the measurement table (itself having neither data nor indexes) being performed. The table aggregates 237 million rows from its child tables. Question What is the proper way to index the dates to avoid full table scans? Options I have considered: GIN GiST Rewrite the WHERE clause Separate year_taken, month_taken, and day_taken columns to the tables What are your thoughts? Thank you!

  Read the article

• A continued saga of C# interoprability with unmanaged C++

  - by Gilad

  After a day of banging my head against the wall both literally and metaphorically, I plead for help: I have an unmanaged C++ project, which is compiled as a DLL. Let's call it CPP Project. It currently works in an unmanaged environment. In addition, I have created a WPF project, that shall be called WPF Project. This project is a simple and currently almost empty project. It contains a single window and I want it to use code from Project 1. For that, I have created a CLR C++ project, which shall be called Interop Project and is also compiled as a DLL. For simplicity I will attach some basic testing code I have boiled down to the basics. CPP Project has the following two testing files: tester.h #pragma once extern "C" class __declspec(dllexport) NativeTester { public: void NativeTest(); }; tester.cpp #include "tester.h" void NativeTester::NativeTest() { int i = 0; } Interop Project has the following file: InteropLib.h #pragma once #include <tester.h> using namespace System; namespace InteropLib { public ref class InteropProject { public: static void Test() { NativeTester nativeTester; nativeTester.NativeTest(); } }; } Lastly, WPF Project has a single window refrencing Interop Project: MainWindow.xaml.cs using System; using System.Windows; using InteropLib; namespace AppGUI { public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); InteropProject.Test(); } } } And the XAML itself has an empty window (default created). Once I am trying to run the WPF project, I get the following error: System.Windows.Markup.XamlParseException: 'The invocation of the constructor on type 'AppGUI.MainWindow' that matches the specified binding constraints threw an exception.' Line number '3' and line position '9'. --- System.IO.FileNotFoundException: Could not load file or assembly 'InteropLib.dll' or one of its dependencies. The specified module could not be found. at AppGUI.MainWindow..ctor() Interestingly enough, if I do not export the class from CPP Project, I do not get this error. Say, if i change tester.h to: #pragma once class NativeTester { public: void NativeTest() { int i = 0; } }; However, in this case I cannot use my more complex classes. If I move my implementation to a cpp file like before, I get unresolved linkage errors due to my not exporting my code. The C++ code I want to actually use is large and has many classes and is object oriented, so I can't just move all my implementation to the h files. Please help me understand this horrific error I've been trying resolve without success. Thanks.

  Read the article

• Multiprogramming in Django, writing to the Database

  - by Marcus Whybrow

  Introduction I have the following code which checks to see if a similar model exists in the database, and if it does not it creates the new model: class BookProfile(): # ... def save(self, *args, **kwargs): uniqueConstraint = {'book_instance': self.book_instance, 'collection': self.collection} # Test for other objects with identical values profiles = BookProfile.objects.filter(Q(**uniqueConstraint) & ~Q(pk=self.pk)) # If none are found create the object, else fail. if len(profiles) == 0: super(BookProfile, self).save(*args, **kwargs) else: raise ValidationError('A Book Profile for that book instance in that collection already exists') I first build my constraints, then search for a model with those values which I am enforcing must be unique Q(**uniqueConstraint). In addition I ensure that if the save method is updating and not inserting, that we do not find this object when looking for other similar objects ~Q(pk=self.pk). I should mention that I ham implementing soft delete (with a modified objects manager which only shows non-deleted objects) which is why I must check for myself rather then relying on unique_together errors. Problem Right thats the introduction out of the way. My problem is that when multiple identical objects are saved in quick (or as near as simultaneous) succession, sometimes both get added even though the first being added should prevent the second. I have tested the code in the shell and it succeeds every time I run it. Thus my assumption is if say we have two objects being added Object A and Object B. Object A runs its check upon save() being called. Then the process saving Object B gets some time on the processor. Object B runs that same test, but Object A has not yet been added so Object B is added to the database. Then Object A regains control of the processor, and has allready run its test, even though identical Object B is in the database, it adds it regardless. My Thoughts The reason I fear multiprogramming could be involved is that each Object A and Object is being added through an API save view, so a request to the view is made for each save, thus not a single request with multiple sequential saves on objects. It might be the case that Apache is creating a process for each request, and thus causing the problems I think I am seeing. As you would expect, the problem only occurs sometimes, which is characteristic of multiprogramming or multiprocessing errors. If this is the case, is there a way to make the test and set parts of the save() method a critical section, so that a process switch cannot happen between the test and the set?

  Read the article

• Issues with LINQ (to Entity) [adding records]

  - by Mario

  I am using LINQ to Entity in a project, where I pull a bunch of data (from the database) and organize it into a bunch of objects and save those to the database. I have not had problems writing to the db before using LINQ to Entity, but I have run into a snag with this particular one. Here's the error I get (this is the "InnerException", the exception itself is useless!): New transaction is not allowed because there are other threads running in the session. I have seen that before, when I was trying to save my changes inside a loop. In this case, the loop finishes, and it tries to make that call, only to give me the exception. Here's the current code: try { //finalResult is a list of the keys to match on for the records being pulled foreach (int i in finalResult) { var queryEff = (from eff in dbMRI.MemberEligibility where eff.Member_Key == i && eff.EffDate >= DateTime.Now select eff.EffDate).Min(); if (queryEff != null) { //Add a record to the Process table Process prRecord = new Process(); prRecord.GroupData = qa; prRecord.Member_Key = i; prRecord.ProcessDate = DateTime.Now; prRecord.RecordType = "F"; prRecord.UsernameMarkedBy = "Autocard"; prRecord.GroupsId = qa.GroupsID; prRecord.Quantity = 2; prRecord.EffectiveDate = queryEff; dbMRI.AddObject("Process", prRecord); } } dbMRI.SaveChanges(); //<-- Crashes here foreach (int i in finalResult) { var queryProc = from pro in dbMRI.Process where pro.Member_Key == i && pro.UsernameMarkedBy == "Autocard" select pro; foreach (var qp in queryProc) { Audit aud = new Audit(); aud.Member_Key = i; aud.ProcessId = qp.ProcessId; aud.MarkDate = DateTime.Now; aud.MarkedByUsername = "Autocard"; aud.GroupData = qa; dbMRI.AddObject("Audit", aud); } } dbMRI.SaveChanges(); //<-- AND here (if the first one is commented out) } catch (Exception e) { //Do Something here } Basically, I need it to insert a record, get the identity for that inserted record and insert a record into another table with the identity from the first record. Given some other constraints, it is not possible to create a FK relationship between the two (I've tried, but some other parts of the app won't allow it, AND my DBA team for whatever reason hates FK's, but that's for a different topic :)) Any ideas what might be causing this? Thank!

  Read the article

• WPF: Order of stretch sizing

  - by RFBoilers

  I'm creating a modal dialog window which contains three essential parts: a TextBlock containing instructions, a ContentControl for the dialog panel, and a ContentControl for the dialog buttons. Each of these parts are contained in a separate Grid row. I have some specific constraints when it comes to how the dialog should be sized. The issue I'm having is with the instructions TextBlock. I want the instructions to be as wide as the ContentControl for the dialog panel. The instructions should then wrap and grow vertically as needed. Should the instructions not be able to grow vertically, then it should begin to grow horizontally. Getting the instructions to be the width of the ContentControl and grow vertically was simple. The part I can't seem to figure out is how to get it to grow horizontally when out of vertical space. My initial thought was to create a class that extends TextBlock and override MeasureOverride. However, that method is sealed. Currently, I'm playing with the idea of have the dialog Window override MeasureOverride to calculate the available size for the instructions block. Am I missing a much simpler way of accomplishing this? Does anyone have any better ideas than this? Messing with MeasureOverride seems like it will be a lot of work. Here is some sample code to give you a general idea of how the dialog is laid out: <Window x:Class="Dialogs.DialogWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Name="dialogWindow" ShowInTaskbar="False" WindowStyle="None" AllowsTransparency="True" Background="Transparent" ResizeMode="NoResize" SizeToContent="WidthAndHeight" WindowStartupLocation="CenterScreen"> <Border Style="{StaticResource WindowBorderStyle}" Margin="15"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> </Grid.RowDefinitions> <TextBlock Margin="25,5" VerticalAlignment="Top" HorizontalAlignment="Left" Text="{Binding Instructions}" TextWrapping="Wrap" Width="{Binding ElementName=panelContentControl, Path=ActualWidth, Mode=OneWay}"/> <ContentControl x:Name="panelContentControl" Grid.Row="1" Margin="25,5" Content="{Binding PanelContent}"/> <ContentControl x:Name="buttonsContentControl" Grid.Row="2" HorizontalAlignment="Right" VerticalAlignment="Center" Margin="25,5" Content="{Binding ButtonsContent}"/> </Grid> </Border> </Window>

  Read the article

• Release management with a distributed version control system

  - by See Sharp Cheddar

  We're considering a switch from SVN to a distributed VCS at my workplace. I'm familiar with all the reasons for wanting to using a DVCS for day-to-day development: local version control, easier branching and merging, etc., but I haven't seen that much that's compelling in terms of managing software releases. Here's our release process: Discover what changes are available for merging. Run a query to find the defects/tickets associated with these changes. Filter out changes associated with "open" tickets. In our environment, tickets must be in a closed state in order to merged with a release branch. Filter out changes we don't want in the release branch. We are very conservative when it comes to merging changes. If a change isn't absolutely necessary, it doesn't get merged. Merge available changes, preferably in chronological order. We group changes together if they're associated with the same ticket. Block unwanted changes from the release branch (svnmerge block) so we don't have to deal with them again. Sometimes we can be juggling 3-5 different milestones at a time. Some milestones have very different constraints, and the block list can get quite long. I've been messing around with git, mercurial and plastic, and as far as I can tell none of them address this model very well. It seems like they would work very well when you have only one product you're releasing, but I can't imagine using them for juggling multiple, very different products from the same codebase. For example, cherry-picking seems to be an afterthought in mercurial. (You have to use the 'transplant' command). After you cherry-pick a change into a branch it still shows up as an available integration. Cherry-picking breaks the mercurial way of working. DVCS seems to be better suited for feature branches. There's no need for cherry-picking if you merge directly from a feature branch to trunk and the release branch. But who wants to do all that merging all the time? And how do you query for what's available to merge? And how do you make sure all the changes in a feature branch belong together? It sounds like total chaos. I'm torn because the coder in me wants DVCS for day-to-day work. I really want it. But I fear the day when I have to put the release manager hat and sort out what needs to be merged and what doesn't. I want to write code, I don't want to be a merge monkey.

  Read the article

• How to manipulate file paths intelligently in .Net 3.0?

  - by Hamish Grubijan

  Scenario: I am maintaining a function which helps with an install - copies files from PathPart1/pending_install/PathPart2/fileName to PathPart1/PathPart2/fileName. It seems that String.Replace() and Path.Combine() do not play well together. The code is below. I added this section: // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); in order to take care of a bug (code is sensitive to a constant @"pending_install\" vs @"pending_install" which I did not like and changed (long story, but there was a good opportunity for constant reuse). Now the whole function: //You want to uncompress only the files downloaded. Not every file in the dest directory. private void UncompressFiles() { string strSrcDir = _application.Client.TempDir; ArrayList arrFiles = new ArrayList(); GetAllCompressedFiles(ref arrFiles, strSrcDir); IEnumerator enumer = arrFiles.GetEnumerator(); while (enumer.MoveNext()) { string strDestFile = enumer.Current.ToString().Replace(_application.Client.TempDir, String.Empty); // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); strDestFile = Path.Combine(_application.Client.BaseDir, strDestFile); strDestFile = strDestFile.Replace(Path.GetExtension(strDestFile), String.Empty); ZSharpLib.ZipExtractor.ExtractZip(enumer.Current.ToString(), strDestFile); FileUtility.DeleteFile(enumer.Current.ToString()); } } Please do not laugh at the use of ArrayList and the way it is being iterated - it was pioneered by a C++ coder during a .Net 1.1 era. I will change it. What I am interested in: what is a better way of replacing PathPart1/pending_install/PathPart2/fileName with PathPart1/PathPart2/fileName within the current code. Note that _application.Client.TempDir is just _application.Client.BaseDir + @"\pending_install". While there are many ways to improve the code, I am mainly concerned with the part which has to do with String.Replace(...) and Path.Combine(,). I do not want to make changes outside of this function. I wish Path.Combine(,) took an optional bool flag, but it does not. So ... given my constraints, how can I rework this so that it starts to sucks less? Thanks!

  Read the article

• Spring MVC, REST, and HATEOAS

  - by SingleShot

  I'm struggling with the correct way to implement Spring MVC 3.x RESTful services with HATEOAS. Consider the following constraints: I don't want my domain entities polluted with web/rest constructs. I don't want my controllers polluted with view constructs. I want to support multiple views. Currently I have a nicely put together MVC app without HATEOAS. Domain entities are pure POJOs without any view or web/rest concepts embedded. For example: class User { public String getName() {...} public String setName(String name) {...} ... } My controllers are also simple. They provide routing and status, and delegate to Spring's view resolution framework. Note my application supports JSON, XML, and HTML, yet no domain entities or controllers have embedded view information: @Controller @RequestMapping("/users") class UserController { @RequestMapping public ModelAndView getAllUsers() { List<User> users = userRepository.findAll(); return new ModelAndView("users/index", "users", users); } @RequestMapping("/{id}") public ModelAndView getUser(@PathVariable Long id) { User user = userRepository.findById(id); return new ModelAndView("users/show", "user", user); } } So, now my issue - I'm not sure of a clean way to support HATEOAS. Here's an example. Let's say when the client asks for a User in JSON format, it comes out like this: { firstName: "John", lastName: "Smith" } Let's also say that when I support HATEOAS, I want the JSON to contain a simple "self" link that the client can then use to refresh the object, delete it, or something else. It might also have a "friends" link indicating how to get the user's list of friends: { firstName: "John", lastName: "Smith", links: [ { rel: "self", ref: "http://myserver/users/1" }, { rel: "friends", ref: "http://myserver/users/1/friends" } ] } Somehow I want to attach links to my object. I feel the right place to do this is in the controller layer as the controllers all know the correct URLs. Additionally, since I support multiple views, I feel like the right thing to do is somehow decorate my domain entities in the controller before they are converted to JSON/XML/whatever in Spring's view resolution framework. One way to do this might be to wrap the POJO in question with a generic Resource class that contains a list of links. Some view tweaking would be required to crunch it into the format I want, but its doable. Unfortunately nested resources could not be wrapped in this way. Other things that come to mind include adding links to the ModelAndView, and then customizing each of Spring's out-of-the-box view resolvers to stuff links into the generated JSON/XML/etc. What I don't want is to be constantly hand-crafting JSON/XML/etc. to accommodate various links as they come and go during the course of development. Thoughts?

  Read the article

• web design PSD to html -> more direct ways?

  - by Assembler

  At work I see one colleague designing a site in Photoshop/Fireworks, I see another taking this data, slicing it up and using Dreamweaver to rebuild the same from scratch. It seems like too much mucking around! I know that Photoshop can output a tables based HTML, and Fireworks will create divs with absolute positioning; neither appear to be very helpful. Admittedly, I haven't tried much of (DW/FW) (CS4/CS3) since becoming a programmer, so I don't know if new versions are addressing this work flow issue, but are we still double handling things? Can we attach some sort of layout metadata (this is a rollover button, this will be a SWF, this will be text, this logo will hide "xyz" <h1> text etc) to slices to aid in layout generation? are there some secret tools which assist in this conversion process? Or are we still restricted to doing things by hand? The frustration continues when said hand built page needs to be reworked again to fit Smarty Templates/Wordpress/generic CMS. I acknowledge that designers need to be free of systems to be able to do whatever, but most conventional sites have: a header with navigation a sidebar with more links the main content part maybe another sidebar a footer Given the similarity of a lot of components, shouldn't there be a more systematic approach to going from sliced designs to functional HTML? Or am I over-simplifying things? -edit- Mmmmm.... I suppose I will accept an answer, but they weren't really what I was looking for. It just seems like designing the DOM is a bit of holy grail ("It's only a model!"), and maybe with all the "groovy" things you can do with HTML and Javascript, it would be mighty hard work, but with a set of constraints (that 960 stuff looks interesting), some well designed reset style sheets and a bit of... fairy dust? we should be able to improve the work flow. Photoshop's tables by themselves are pretty much useless, I agree, but surely we can take this data, and then select a group of cells and say "right, this is a text div, overflow:auto" or "these cells are an image block, style it with the same height/width as the selected area". Admittedly here at work there are other elephants in the room that need to make their formal introductions to management, but some parts of the designpage workflow seem... uneducated at best.

  Read the article

• How to manipulate file paths intelligently in .Net 3.5?

  - by Hamish Grubijan

  Scenario: I am maintaining a function which helps with an install - copies files from PathPart1/pending_install/PathPart2/fileName to PathPart1/PathPart2/fileName. It seems that String.Replace() and Path.Combine() do not play well together. The code is below. I added this section: // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); in order to take care of a bug (code is sensitive to a constant @"pending_install\" vs @"pending_install" which I did not like and changed (long story, but there was a good opportunity for constant reuse). Now the whole function: //You want to uncompress only the files downloaded. Not every file in the dest directory. private void UncompressFiles() { string strSrcDir = _application.Client.TempDir; ArrayList arrFiles = new ArrayList(); GetAllCompressedFiles(ref arrFiles, strSrcDir); IEnumerator enumer = arrFiles.GetEnumerator(); while (enumer.MoveNext()) { string strDestFile = enumer.Current.ToString().Replace(_application.Client.TempDir, String.Empty); // The behavior of Path.Combine is weird. See: // http://stackoverflow.com/questions/53102/why-does-path-combine-not-properly-concatenate-filenames-that-start-with-path-dir while (strDestFile.StartsWith(@"\"")) { strDestFile = strDestFile.Substring(1); // Remove any leading backslashes } Debug.Assert(!Path.IsPathRooted(strDestFile), "This will make the Path.Combine(,) fail)."); strDestFile = Path.Combine(_application.Client.BaseDir, strDestFile); strDestFile = strDestFile.Replace(Path.GetExtension(strDestFile), String.Empty); ZSharpLib.ZipExtractor.ExtractZip(enumer.Current.ToString(), strDestFile); FileUtility.DeleteFile(enumer.Current.ToString()); } } Please do not laugh at the use of ArrayList and the way it is being iterated - it was pioneered by a C++ coder during a .Net 1.1 era. I will change it. What I am interested in: what is a better way of replacing PathPart1/pending_install/PathPart2/fileName with PathPart1/PathPart2/fileName within the current code. Note that _application.Client.TempDir is just _application.Client.BaseDir + @"\pending_install". While there are many ways to improve the code, I am mainly concerned with the part which has to do with String.Replace(...) and Path.Combine(,). I do not want to make changes outside of this function. I wish Path.Combine(,) took an optional bool flag, but it does not. So ... given my constraints, how can I rework this so that it starts to suck less?

  Read the article

• How do I 'globally' catch exceptions thrown in object instances.

  - by SleepyBobos

  I am currently writing a winforms application (C#). I am making use of the Enterprise Library Exception Handling Block, following a fairly standard approach from what I can see. IE : In the Main method of Program.cs I have wired up event handler to Application.ThreadException event etc. This approach works well and handles the applications exceptional circumstances. In one of my business objects I throw various exceptions in the Set accessor of one of the objects properties set { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum trim..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message..."); _minimumTrim = value; } My logic for this approach (without turning this into a 'when to throw exceptions' discussion) is simply that the business objects are responsible for checking business rule constraints and throwing an exception that can bubble up and be caught as required. It should be noted that in the UI of my application I do explictly check the values that the public property is being set to (and take action there displaying friendly dialog etc) but with throwing the exception I am also covering the situation where my business object may not be used by a UI eg : the Property is being set by another business object for example. Anyway I think you all get the idea. My issue is that these exceptions are not being caught by the handler wired up to Application.ThreadException and I don't understand why. From other reading I have done the Application.ThreadException event and it handler "... catches any exception that occurs on the main GUI thread". Are the exceptions being raised in my business object not in this thread? I have not created any new threads. I can get the approach to work if I update the code as follows, explicity calling the event handler that is wired to Application.ThreadException. This is the approach outlined in Enterprise Library samples. However this approach requires me to wrap any exceptions thrown in a try catch, something I was trying to avoid by using a 'global' handler to start with. try { if (value > MaximumTrim) throw new CustomExceptions.InvalidTrimValue("The value of the minimum..."); if (!availableSubMasterWidthSatisfiesAllPatterns(value)) throw new CustomExceptions.InvalidTrimValue("Another message"); _minimumTrim = value; } catch (Exception ex) { Program.ThreadExceptionHandler.ProcessUnhandledException(ex); } I have also investigated using wiring a handler up to AppDomain.UnhandledException event but this does not catch the exceptions either. I would be good if someone could explain to me why my exceptions are not being caught by my global exception handler in the first code sample. Is there another approach I am missing or am I stuck with wrapping code in try catch, shown above, as required?

  Read the article

• What web platform is right for me?

  - by egervari

  I've been looking at web frameworks like Rails, Grails, etc. I'm used to doing applications in Spring Framework with Hibernate... and I want something more productive. One of the things I realized is that while some of the things in Grails is sexy, there are some serious problems with it. Grails' controllers: 1) are implemented awfully. They don't seem to be able to extend from super classes at runtime. I tried this to add base actions and helper methods, and this seems to cause grails to blow up. 2) are based on an obsolete request parameters model (rather than form backing objects, which are much nicer). 3) are hard to test. Command objects are treated totally differently... and it's actually MUCH harder to write the test than it is to write the controller code. 4) Command objects operate totally differently. They are pre-validated and bound, which causes a lot of inconsistencies than basic parameter model. 5) Command objects are not reusable, and it's a pain in the rear to reuse most of the stuff from the domain classes, like constraints and fields. This is TRIVIAL to do in basic Spring. Why the hell was it not trivial to do in Grails? 6) The scaffolding that is generated is pure crap. It doesn't generalize inserts and updates... and it actually copy/pastes a pile of code in two views: create.gsp and edit.gsp. The views themselves are gargantuan piles of doggie do-do. This is further compounded by the fact that it uses low-level parameters and not objects. Integration tests are 30x slower than a Spring integration test. It is disgusting. Some mocking tests are so hard to write and aren't guaranteed to work when it's deployed, that I think it discourages fast, tdd test cycles. Most things seem to screw up grails while it's running, like adding a taglib, or anything really. The server restart problem wasn't solved at all. I'm starting to think going with Spring/Hibernate/Java is the only way to go. While there is a pretty big cost at startup, I know it'll eventually smooth out. It sucks I can't use a language like Scala... because idiomatically, it is so incompatible with Hibernate. This app is also not a run-of-the-mill UI over a database. It's got some of that, but it's not going to be a slouch. I am deathly scared of Grails now because of how crap it is in the Controller layer. Suggestions on what I can do?

  Read the article

• Realtime MySQL search results on an advanced search page

  - by Andrew Heath

  I'm a hobbyist, and started learning PHP last September solely to build a hobby website that I had always wished and dreamed another more competent person might make. I enjoy programming, but I have little free time and enjoy a wide range of other interests and activities. I feel learning PHP alone can probably allow me to create 98% of the desired features for my site, but that last 2% is awfully appealing: The most powerful tool of the site is an advanced search page that picks through a 1000+ record game scenario database. Users can data-mine to tremendous depths - this advanced page has upwards of 50 different potential variables. It's designed to allow the hardcore user to search on almost any possible combination of data in our database and it works well. Those who aren't interested in wading through the sea of options may use the Basic Search, which is comprised of the most popular parts of the Advanced search. Because the advanced search is so comprehensive, and because the database is rather small (less than 1,200 potential hits maximum), with each variable you choose to include the likelihood of getting any qualifying results at all drops dramatically. In my fantasy land where I can wield AJAX as if it were Excalibur, my users would have a realtime Total Results counter in the corner of their screen as they used this page, which would automatically update its query structure and report how many results will be displayed with the addition of each variable. In this way it would be effortless to know just how many variables are enough, and when you've gone and added one that zeroes out the results set. A somewhat similar implementation, at least visually, would be the Subtotal sidebar when building a new custom computer on IBuyPower.com For those of you actually still reading this, my question is really rather simple: Given the time & ability constraints outlined above, would I be able to learn just enough AJAX (or whatever) needed to pull this one feature off without too much trouble? would I be able to more or less drop-in a pre-written code snippet and tweak to fit? or should I consider opening my code up to a trusted & capable individual in the future for this implementation? (assuming I can find one...) Thank you.

  Read the article

• Wake up thread blocked on accept() call

  - by selbie

  Sockets on Linux question I have a worker thread that is blocked on an accept() call. It simply waits for an incoming network connection, handles it, and then returns to listening for the next connection. When it is time for the program to exit, how do I signal this network worker thread (from the main thread) to return from the accept() call while still being able to gracefully exit its loop and handle it's cleanup code. Some things I tried: 1. pthread_kill to send a signal. Feels kludgy to do this, plus it doesn't reliably allow the thread to do it's shutdown logic. Also makes the program terminate as well. I'd like to avoid signals if at all possible. pthread_cancel. Same as above. It's a harsh kill on the thread. That, and the thread may be doing something else. Closing the listen socket from the main thread in order to make accept() abort. This doesn't reliably work. Some constraints: If the solution involves making the listen socket non-blocking, that is fine. But I don't want to accept a solution that involves the thread waking up via a select call every few seconds to check the exit condition. The thread condition to exit may not be tied to the process exiting. Essentially, the logic I am going for looks like this. void* WorkerThread(void* args) { DoSomeImportantInitialization(); // initialize listen socket and some thread specific stuff while (HasExitConditionBeenSet()==false) { listensize = sizeof(listenaddr); int sock = accept(listensocket, &listenaddr, &listensize); // check if exit condition has been set using thread safe semantics if (HasExitConditionBeenSet()) { break; } if (sock < 0) { printf("accept returned %d (errno==%d)\n", sock, errno); } else { HandleNewNetworkCondition(sock, &listenaddr); } } DoSomeImportantCleanup(); // close listen socket, close connections, cleanup etc.. return NULL; } void SignalHandler(int sig) { printf("Caught CTRL-C\n"); } void NotifyWorkerThreadToExit(pthread_t thread_handle) { // signal thread to exit } int main() { void* ptr_ret= NULL; pthread_t workerthread_handle = 0; pthread_create(&workerthread, NULL, WorkerThread, NULL); signal(SIGINT, SignalHandler); sleep((unsigned int)-1); // sleep until the user hits ctrl-c printf("Returned from sleep call...\n"); SetThreadExitCondition(); // sets global variable with barrier that worker thread checks on // this is the function I'm stalled on writing NotifyWorkerThreadToExit(workerthread_handle); // wait for thread to exit cleanly pthread_join(workerthread_handle, &ptr_ret); DoProcessCleanupStuff(); }

  Read the article

• Writing OpenGL enabled GUI

  - by Jaen

  I am exploring a possibility to write a kind of a notebook analogue that would reproduce the look and feel of using a traditional notebook, but with the added benefit of customizing the page in ways you can't do on paper - ask the program to lay ruled paper here, grid paper there, paste an image, insert a recording from the built-in camera, try to do handwriting recognition on the tablet input, insert some latex for neat formulas and so on. I'm pretty interested in developing it just to see if writing notes on computer can come anywhere close to the comfort plain paper + pencil offer (hard to do IMO) and can always turn it in as a university C++ project, so double gain there. Coming from the type of project there are certain requirements for the user interface: the user will be able to zoom, move and rotate the notebook as he wishes and I think it's pretty sensible delegate it to OpenGL, so the prospective GUI needs to work well with OGL (preferably being rendered in it) the interface should be navigable with as little of keyboard input as user wishes (incorporating some sort of gestures maybe) up to limiting the keyboard keys as modifiers to the pen movements and taps; this includes tablet and possible multitouch support the interface should keep out of the way where not needed and come up where needed and be easily layerable the notebook sheet itself will be a container for objects representing the notebook blurbs, so it would be nice if the GUI would be able to overlay some frames over the exact parts of the OpenGL-drawn sheet to signify what can be done with given part (like moving, rotating, deleting, copying, editing etc.) and it's extents In terms of interface it's probably going to end up similar to Alias' Sketch Book Pro: [picture][http://1.bp.blogspot.com/_GGxlzvZW-CY/SeKYA_oBdSI/AAAAAAAAErE/J6A0kyXiuqA/s400/Autodesk_Alias_SketchBook_Pro_2.jpg] As far as toolkits go I'm considering Qt and nui, but I'm not really aware how well would they match up the requirements and how well would they handle such an application. As far as I know you can somehow coerce Qt into doing widget drawing with OpenGL, but on the other hand I heard voices it's slot-signal framework isn't exactly optimal and requires it's own preprocessor and I don't know how hard would be to do all the custom widgets I would need (say color-wheel, ruler, blurb frames, blurb selection, tablet-targeted pop-up menu etc.) in the constraints of Qt. Also quite a few Qt programs I've had on my machine seemed really sluggish, but it may be attributed to me having old PC or programmers using Qt suboptimally rather to the framework itself. As for [nui][http://www.libnui.net/] I know it's also cross-platform and all of the basic things you would require of a GUI toolkit and what is the biggest plus it is OpenGL-enabled from the start, but I don't know how it is with custom widgets and other facets and it certainly has smaller userbase and less elaborate documentation than Qt. The question goes as this: Does any of these toolkits fulfill (preferably all of) the requirements or there is a well fitting toolkit I haven't come across or maybe I should just roll up my sleeves, get SFML (or maybe Clutter would be more suited to this?) and something like FastDelegates or libsigc++ and program the GUI framework from the ground up myself? I would be very glad if anyone had experience with a similar GUI project and can offer some comments on how well these toolkits hold up or is it worthwhile to pursue own GUI toolkit in this case. Sorry for longwindedness, duh.

  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

< Previous Page | 37 38 39 40 41 42 43 44 45  | Next Page >