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  • Design pattern to keep track UITableView rows correspondance to underlying data in constant time.

    - by DenNukem
    When my model changes I want to animate changes in UITableView by inserting/deleting rows. For that I need to know the ordinal of the given row (so I can construct NSIndexPath), which I find hard to do in better-than-linear time. For example, consider that I have a list of addressbook entries which are manualy sorted by the user, i.e. there is no ordering "key" that represents the sort order. There is also a corresponding UITableView that shows one row per addressbook entry. When UITableView queries the datasource I query the NSMUtableArray populated with my entries and return required data in constant time for each row. However, if there is a change in underlying model I am getting a notification "Joe Smith, id#123 has been removed". Now I have a dilemma. A naive approach would be to scan the array, determine the index at which Joe Smith is and then ask UITableView to remove that precise row from the view, also removing it form the array. However, the scan will take linear time to finish. Now I could have an NSDictionary which allows me to find Joe Smith in constant time, but that doesn't do me a lot of good because I still need to find his ordinal index within the array in order to instruct UITableView to remove that row, which is again a linear search. I could further decide to store each object's ordinal inside the object itself to make it constant, but it will become outdated after first such update as all subsequent index values will have changed due to removal of an object. So what is the correct design pattern to accurately reflect model changes in the UITableView in costant (or at least logarithmic) time?

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  • RESTful design, how to name pages outside CRUD et al?

    - by sscirrus
    Hi all, I'm working on a site that has quite a few pages that fall outside my limited understanding of RESTful design, which is essentially: Create, Read, Update, Delete, Show, List Here's the question: what is a good system for labeling actions/routes when a page doesn't neatly fall into CRUD/show/list? Some of my pages have info about multiple tables at once. I am building a site that gives some customers a 'home base' after they log on. It does NOT give them any information about themselves so it shouldn't be, for example, /customers/show/1. It does have information about companies, but there are other pages on the site that do that differently. What do you do when you have these situations? This 'home-base' is shown to customers and it mainly has info about companies (but not uniquely so). Second case: I have a table called 'Matchings' in between customers and companies. These matchings are accessed in completely different ways on different parts of the site (different layouts, different CSS sheets, different types of users accessing them, etc. They can't ALL be matchings/show. What's the best way to label the others? Thanks very much. =)

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  • How to design Models the correct way: Object-oriented or "Package"-oriented?

    - by ajsie
    I know that in OOP you want every object (from a class) to be a "thing", eg. user, validator etc. I know the basics about MVC, how they different parts interact with each other. However, i wonder if the models in MVC should be designed according to the traditional OOP design, that is to say, should every model be a database/table/row (solution 2)? Or is the intention more like to collect methods that are affecting the same table or a bunch of related tables (solution 1). example for an Address book module in CodeIgniter, where i want be able to "CRUD" a Contact and add/remove it to/from a CRUD-able Contact Group. Models solution 1: bunching all related methods together (not real object, rather a "package") class Contacts extends Model { function create_contact() {) function read_contact() {} function update_contact() {} function delete_contact() {} function add_contact_to_group() {} function delete_contact_from_group() {} function create_group() {} function read_group() {} function update_group() {} function delete_group() {} } Models solution 2: the OOP way (one class per file) class Contact extends Model { private $name = ''; private $id = ''; function create_contact() {) function read_contact() {} function update_contact() {} function delete_contact() {} } class ContactGroup extends Model { private $name = ''; private $id = ''; function add_contact_to_group() {} function delete_contact_from_group() {} function create_group() {} function read_group() {} function update_group() {} function delete_group() {} } i dont know how to think when i want to create the models. and the above examples are my real tasks for creating an Address book. Should i just bunch all functions together in one class. then the class contains different logic (contact and group), so it can not hold properties that are specific for either one of them. the solution 2 works according to the OOP. but i dont know why i should make such a dividing. what would the benefits be to have a Contact object for example. Its surely not a User object, so why should a Contact "live" with its own state (properties and methods). you experienced guys with OOP/MVC, please shed a light on how one should think here in this very concrete task.

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  • Java OO design confusion: how to handle actions modified by states modified by actions...

    - by Arvanem
    Hi folks, Given an entity, whose action is potentially modified by states (of the entity and other entities) in turn potentially modified by other actions (of the entity and other entities) , what is the best way to code or design to handle the potential existence of the modifiers? Speaking metaphorically, I am coding a Java application representing a piano. As you know a piano has keys (which, when pressed, emit sound) and pedals (which, when pressed, modify the keys' sounds). My base class structure is as follows: Entity (for keys and pedals) State (this holds each entity's states, e.g. name such as "soft pedal", and boolean "Pressed"), Action (this holds each entity's actions, e.g. play sound when pressed, or modify others sounds). By composition, the Entity class has a copy of each of State and Action inside it. e.g.: public class Entity { State entityState = new State(); Action entityAction = new Action(); Thus I have coded a "C-Sharp" key Entity. When I "press" that entity (set its "Pressed" state to true), its action plays a "C-Sharp" sound and then sets its "Pressed" state to false. At the same time, if the "C-Sharp" key entity is not "tuned", its sound deviates from "C-Sharp". Meanwhile I have coded a "soft pedal" Entity. When that entity is "pressed", no sound plays but its action is to make softer the sound of the "C-Sharp" and other key entities. I have also coded a "sustain pedal" Entity. When that entity is "pressed", no sound plays but its action is to enable reverberation of the sound of the "C-Sharp" and other key entities. Both the "soft" and "sustain pedals" can be pressed at the same time with the result that keys entities become both softened and reverberating. In short, I do not understand how to make this simultaneous series of states and actions modify each other in a sensible OO way. I am wary of coding a massive series of "if" statements or "switches". Thanks in advance for any help or links you can offer.

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  • Design PDF template and populate data at runtime using java,xml etc..

    - by Samant
    well i have been looking for a java based PDF solutions...we dont have a clean way i guess-still.. all solutions are primitive and kind of workarounds... No easy solution for this requirement - 1. Designing a PDF template using a IDE (eg. Livecycle designer ..which is not free) 2. Then at runtime using java, populate data into this PDF template...either using xml or other datasources... such a simple requirement and NONE has a good "open-source and free" solution yet ! Is anyone aware of any ? I have been searching for since 3-4 years now..for a clean way out... Eclipse BIRT comes close.. but does not handle Barcode elements ..OOB. Jasper - ireport is also good but that tool does not have a table concept and is kind of annoying ! Also barcode support is not good. XSL-FO has not free IDE for design . Looking for a better answer .. got one ?

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  • How to simplify this code or a better design?

    - by Tattat
    I am developing a game, the game have different mode. Easy, Normal, and Difficult. So, I'm thinking about how to store the game mode. My first idea is using number to represent the difficulty. Easy = 0 Normal = 1 Difficult = 2 So, my code will have something like this: switch(gameMode){ case 0: //easy break; case 1: //normal break; case 3: //difficult break; } But I think it have some problems, if I add a new mode, for example, "Extreme", I need to add case 4... ... it seems not a gd design. So, I am thinking making a gameMode object, and different gameMode is sub class of the super class gameMode. The gameMode object is something like this: class GameMode{ int maxEnemyNumber; int maxWeaponNumber; public static GameMode init(){ GameMode gm = GameMode(); gm.maxEnemyNumber = 0; gm.maxWeaponNumber = 0; return gm; } } class EasyMode extends GameMode{ public static GameMode init(){ GameMode gm = super.init(); gm.maxEnemyNumber = 10; gm.maxWeaponNumber = 100; return gm; } } class NormalMode extends GameMode{ public static GameMode init(){ GameMode gm = super.init(); gm.maxEnemyNumber = 20; gm.maxWeaponNumber = 80; return gm; } } But I think it seems too "bulky" to create an object to store gameMode, my "gameMode" only store different variables for game settings.... Is that any simple way to store data only instead of making an Object? thz u.

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  • What Color is the Windows' System.Control? (Visual Studio Design View)

    - by jp2code
    In Visual Studio Design View, the selection of Form Colors in the Properties Pane are selectable from the "Custom", "Web", and "System" tabs. Of course, the color number can be used, too. When the "System" Tab is selected, the colors in the list depend on what type of Theme the Computer User has set on the PC. I'd like to stick with this, but I need to know how to "read in" the colors. I have controls that I create "on-the-fly" or often need to change a color back after getting the person's attention using a blink/flicker technique. How do I get the list of System Theme colors? Most forms have a BackColor that defaults to "Control", which looks like a very light gray under Windows 7, running the default Windows 7 Theme. I've managed to grab a color by physically reading the ARGB value in code, but I'd rather have a way to access the colors by their Theme Name, if that can be done. public Form1() { Color cControl = this.BackColor; Console.WriteLine(cControl.Name); // there is not always a name! } Does anyone know what I'm talking about?

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  • Mis-spelling in the .NET configuration system, a design flaw?

    - by smwikipedia
    I just wrote some .NET code to get connection string from the config file. The config file is as below: <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="key1" value="hello,world!"/> </appSettings> <connectionStrings> <add name="conn1" connectionString="abcd"/> </connectionStrings> </configuration> .NET Framework provide the following types to get the connection string: 1- ConnectionStringsSection : stands for the config section containing several connection strings 2- ConnectionStringSettingsCollection : stands for the connection string collection 3- ConnectionStringSettings : stands for a certain connection string. .NET Framework also provide the following types to get the App Settings: 4- AppSettingsSection 5- KeyValueConfigurationCollection 6- KeyValueConfigurationElement Compare 2 to 5, 3 to 6, why are there extra "s" in ConnectionStringSetting[s]Collection and ConnectionStringSetting[s]? This mis-spelling is really mis-leading. I think it's a design flaw. Has anyone noticed that?

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  • C#: at design time, how can I reliably determine the type of a variable that is declared using var?

    - by Cheeso
    I'm working on a completion (intellisense) facility for C# in emacs. The idea is, if a user types a fragment, then asks for completion via a particular keystroke combination, the completion facility will use .NET reflection to determine the possible completions. Doing this requires that the type of the thing being completed, be known. If it's a string, it has a set of known methods; if it's an Int32, it has a separate set of methods, and so on. Using semantic, a code lexer/parser package available in emacs, I can locate the variable declarations, and their types. Given that, it's straightforward to use reflection to get the methods and properties on the type, and then present the list of options to the user. The problem arrives when the code uses var in the declaration. How can I reliably determine the actual type used, when the variable is declared with the var keyword? Just to be clear, I don't need to determine it at runtime. I want to determine it at "Design time". So far the best idea I have is: extract the declaration statement, eg var foo = "a string value"; concatenate a statement foo.GetType(); dynamically compile the resulting C# fragment it into a new assembly load the assembly into a new AppDomain, run the framgment and get the return type. unload and discard the assembly This sounds awfully heavyweight, for each completion request in the editor. Any better ideas out there?

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  • How can i design a DB where the user can define the fields and types of a detail table in a M-D rela

    - by Simon
    My application has one table called 'events' and each event has approx 30 standard fields, but also user defined fields that could be any name or type, in an 'eventdata' table. Users can define these event data tables, by specifying x number of fields (either text/double/datetime/boolean) and the names of these fields. This 'eventdata' (table) can be different for each 'event'. My current approach is to create a lookup table for the definitions. So if i need to query all 'event' and 'eventdata' per record, i do so in a M-D relaitionship using two queries (i.e. select * from events, then for each record in 'events', select * from 'some table'). Is there a better approach to doing this? I have implemented this so far, but most of my queries require two distinct calls to the DB - i cannot simply join my master 'events' table with different 'eventdata' tables for each record in in 'events'. I guess my main question is: can i join my master table with different detail tables for each record? E.g. SELECT E.*, E.Tablename FROM events E LEFT JOIN 'E.tablename' T ON E._ID = T.ID If not, is there a better way to design my database considering i have no idea on how many user defined fields there may be and what type they will be.

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  • Need a design approach or suggestion for a simple structure using Servlet.

    - by akshay
    Hi I have to design such that whenever user pass a query I process it using servlet and then call the js page to draw the chart 1 user writes a query on a page 2 the page call the servelt class public class MyServlet extends Httpservlet implements DataSourceServlet {..... return data The user see a beautiful string like this.. google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); 3 when the user hits on different html page myhtml.js it draws the chart. I want the Myservlet class itself call the myhtml.js page and draw the chart directly. and want to eliminate the beautiful string google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); from coming on user's browser What should i do? I tried using functions to call another page like request dispatcher(), redirect() calling myhtml.js page directly after myservlet process the query results. But i get the result like this google.visualization.Query.setResponse......... /Tiger'},{v:80.0}, {v:false}]}]}}); and the entire myhtml.js code page below it on the browsers that to without the chart been draw. Is there anyway to element the beautiful string from coming on clients browser and only show them the chart been drawn ? :) This is the small tutorial i am following http://code.google.com/apis/visualization/documentation/dev/dsl_get_started.html

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  • What would be the Better db design for the old db structure?

    - by yawok
    i've a old database where i store the data of the holidays and dates in which they are celebrated.. id country hdate description link 1 Afghanistan 2008-01-19 Ashura ashura 2 Albania 2008-01-01 New Year Day new-year the flaws in the above structure is that, i repeat the data other than date for every festival and every year and every country.. For example, I store a new date for 2009 for ashura and afghanistan .. I tried to limit the redundancy and split the tables as countries (id,name) holidays (id, holiday, celebrated_by, link) // celebrated_by will store the id's of countries separated by ',' holiday_dates (holiday_id, date, year) // date will the full date and year will be as 2008 or 2009 Now i have some problems with the structure too.. consider that i store the holiday like Independence day , its common for more countries but will have different dates. so how to handle this and and the link will have to be different too.. And i need to list the countries which celebrates the same holiday and also when i describe about a single holiday i need to list all the other holidays that country would be celebrating.. And the most of all , i already have huge amount of data in the old tables and i need to split it to the new one once the new design is finalized... Any ideas?

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  • Puppet - Possible to use software design patterns in modules?

    - by Mike Purcell
    As I work with puppet, I find myself wanting to automate more complex setups, for example vhosts for X number of websites. As my puppet manifests get more complex I find it difficult to apply the DRY (don't repeat yourself) principle. Below is a simplified snippet of what I am after, but doesn't work because puppet throws various errors depending up whether I use classes or defines. I'd like to get some feed back from some seasoned puppetmasters on how they might approach this solution. # site.pp import 'nodes' # nodes.pp node nodes_dev { $service_env = 'dev' } node nodes_prod { $service_env = 'prod' } import 'nodes/dev' import 'nodes/prod' # nodes/dev.pp node 'service1.ownij.lan' inherits nodes_dev { httpd::vhost::package::site { 'foo': } httpd::vhost::package::site { 'bar': } } # modules/vhost/package.pp class httpd::vhost::package { class manage($port) { # More complex stuff goes here like ensuring that conf paths and uris exist # As well as log files, which is I why I want to do the work once and use many notify { $service_env: } notify { $port: } } define site { case $name { 'foo': { class 'httpd::vhost::package::manage': port => 20000 } } 'bar': { class 'httpd::vhost::package::manage': port => 20001 } } } } } That code snippet gives me a Duplicate declaration: Class[Httpd::Vhost::Package::Manage] error, and if I switch the manage class to a define, and attempt to access a global or pass in a variable common to both foo and bar, I get a Duplicate declaration: Notify[dev] error. Any suggestions how I can implement the DRY principle and still get puppet to work? -- UPDATE -- I'm still having a problem trying to ensure that some of my vhosts, which may share a parent directory, are setup correctly. Something like this: node 'service1.ownij.lan' inherits nodes_dev { httpd::vhost::package::site { 'foo_sitea': } httpd::vhost::package::site { 'foo_siteb': } httpd::vhost::package::site { 'bar': } } What I need to happen is that sitea and siteb have the same parent "foo" folder. The problem I am having is when I call a define to ensure the "foo" folder exists. Below is the site define as I have it, hopefully it will make sense what I am trying to accomplish. class httpd::vhost::package { File { owner => root, group => root, mode => 0660 } define site() { $app_parts = split($name, '[_]') $app_primary = $app_parts[0] if ($app_parts[1] == '') { $tpl_path_partial_app = "${app_primary}" $app_sub = '' } else { $tpl_path_partial_app = "${app_primary}/${app_parts[1]}" $app_sub = $app_parts[1] } include httpd::vhost::log::base httpd::vhost::log::app { $name: app_primary => $app_primary, app_sub => $app_sub } } } class httpd::vhost::log { class base { $paths = [ '/tmp', '/tmp/var', '/tmp/var/log', '/tmp/var/log/httpd', "/tmp/var/log/httpd/${service_env}" ] file { $paths: ensure => directory } } define app($app_primary, $app_sub) { $paths = [ "/tmp/var/log/httpd/${service_env}/${app_primary}", "/tmp/var/log/httpd/${service_env}/${app_primary}/${app_sub}" ] file { $paths: ensure => directory } } } The include httpd::vhost::log::base works fine, because it is "included", which means it is only implemented once, even though site is called multiple times. The error I am getting is: Duplicate declaration: File[/tmp/var/log/httpd/dev/foo]. I looked into using exec, but not sure this is the correct route, surely others have had to deal with this before and any insight is appreciated as I have been grappling with this for a few weeks. Thanks.

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  • split virtualization design based on environment or server role?

    - by Dan
    I'm setting up the server environment for a new software development group, which will include 4 test environments. These are web applications, so each environment will have an application server and a database server. I'm planning on buying two physical servers (e.g. 6-core CPU each with 12GB or so of RAM), and I'm thinking virtualization is appropriate here. With that in mind, I've thought of a couple ways that I could organize the virtualization strategy: - Separated by server role: Server 1 has all the application servers, each in their own guest VM. Server 2 has all the databases. OR - Separated by environment: Server 1 has a VM for two of the environments, with the VM containing both the app server and the database server. Server 2 would also contain two test environments, with the same style (app server and database in same VM). The advantages I see with all the app servers on one server and all the databases on another server is that I could probably be more efficient with the database server (one instance running multiple databases). But the other option seems easier to manage (archives/restorations would be contained in a single VM). Any recommendations? TIA.

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  • A design for watching IPTV anywhere in the house?

    - by Carlos
    I'm currently getting TV and internet via IP to my house. The service comes into an ISP-supplied Router (ST585) which is in turn connected to an IPTV box. I need to replace the router, as it's port forwarding seems to be broken, so I was thinking of getting a box with an IGMP proxy. I once mistakenly got a non-IGMP box, with the result that the internet worked, but the IPTV didn't. The trouble is, I have no idea how to set up the IPTV part of the installation. I do have a copy of the ST585 configuration, but it doesn't look anything like the Cisco stuff that I learned about at CCNA. What are the steps necessary to reproduce the IGMP setup? I was thinking of WireSharking the communications on the network, but I suppose I'd need a hub for that? As a bonus, since the packets are coming in with the TV signal, is it possible to mess with the IGMP setup so I can watch TV anywhere in the house?

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  • A design for watching IPTV anywhere in the house?

    - by Carlos
    I'm currently getting TV and internet via IP to my house. The service comes into an ISP-supplied Router (ST585) which is in turn connected to an IPTV box. I need to replace the router, as it's port forwarding seems to be broken, so I was thinking of getting a box with an IGMP proxy. I once mistakenly got a non-IGMP box, with the result that the internet worked, but the IPTV didn't. The trouble is, I have no idea how to set up the IPTV part of the installation. I do have a copy of the ST585 configuration, but it doesn't look anything like the Cisco stuff that I learned about at CCNA. What are the steps necessary to reproduce the IGMP setup? I was thinking of WireSharking the communications on the network, but I suppose I'd need a hub for that? As a bonus, since the packets are coming in with the TV signal, is it possible to mess with the IGMP setup so I can watch TV anywhere in the house?

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  • how to design network for connectivity between private and corporate LANs?

    - by maruti
    there is a bunch of servers connected to shared storage in a private LAN (10.x.x.x). this privateLAN is managed by a windows server (DHCP, DNS and directory services) these hosts need to be from outside of the datacenter Eg. Remote desktop. can the NIC2 on each of the hosts be connected to the other public LAN (compromising speed or security? what are improtant considerations: additional hardware? like switches? routing&DNS software? currently available hardware : Dell Powerconnect 6224 switch .... planning this for storage network. software: windows 2003 server for DHCP, DNS, A/D ? would it be more flexible to use Linux distributions like IPCOP, Untangle etc? all that I am looking for is good isolation between private and other networks, avoid DHCP, DNS, AD clashes.

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  • On Ubuntu, how to design a monitor to run a process when a file is written to a directory?

    - by J G
    I want to run a process when a file is written to a directory on Ubuntu. I understand I can write a monitor to do this. (ie not an event based trigger but a 'monitor'). To implement this - other than writing a for loop of infinite duration in C that polls the directory - what steps would you take to implement this? What steps would you take to implement a monitor on Ubuntu that runs a process (another application) when a file is written to a directory? (The reason that you'd do this is the that process writing the file is under a limited set of permissions (eg tomcat6) but the executed process (an existing software package) needs root (ie to run a process in a chroot jail))

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  • how to design LAN connectivity between private and corporate ?

    - by maruti
    there is a bunch of servers connected to shared storage in a private LAN (10.x.x.x). this privateLAN is managed by a windows server (DHCP, DNS and directory services). how can these hosts be accessed from outside of this privateLAN? Eg. Remote desktop. can the NIC2 on each of the hosts be connected to the other public LAN (compromising speed or security? what are improtant considerations: additional hardware? like switches? routing&DNS software?

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  • How to best design a date/geographic proximity query on GAE?

    - by Dane
    Hi all, I'm building a directory for finding athletic tournaments on GAE with web2py and a Flex front end. The user selects a location, a radius, and a maximum date from a set of choices. I have a basic version of this query implemented, but it's inefficient and slow. One way I know I can improve it is by condensing the many individual queries I'm using to assemble the objects into bulk queries. I just learned that was possible. But I'm also thinking about a more extensive redesign that utilizes memcache. The main problem is that I can't query the datastore by location because GAE won't allow multiple numerical comparison statements (<,<=,=,) in one query. I'm already using one for date, and I'd need TWO to check both latitude and longitude, so it's a no go. Currently, my algorithm looks like this: 1.) Query by date and select 2.) Use destination function from geopy's distance module to find the max and min latitude and longitudes for supplied distance 3.) Loop through results and remove all with lat/lng outside max/min 4.) Loop through again and use distance function to check exact distance, because step 2 will include some areas outside the radius. Remove results outside supplied distance (is this 2/3/4 combination inefficent?) 5.) Assemble many-to-many lists and attach to objects (this is where I need to switch to bulk operations) 6.) Return to client Here's my plan for using memcache.. let me know if I'm way out in left field on this as I have no prior experience with memcache or server caching in general. -Keep a list in the cache filled with "geo objects" that represent all my data. These have five properties: latitude, longitude, event_id, event_type (in anticipation of expanding beyond tournaments), and start_date. This list will be sorted by date. -Also keep a dict of pointers in the cache which represent the start and end indices in the cache for all the date ranges my app uses (next week, 2 weeks, month, 3 months, 6 months, year, 2 years). -Have a scheduled task that updates the pointers daily at 12am. -Add new inserts to the cache as well as the datastore; update pointers. Using this design, the algorithm would now look like: 1.) Use pointers to slice off appropriate chunk of list based on supplied date. 2-4.) Same as above algorithm, except with geo objects 5.) Use bulk operation to select full tournaments using remaining geo objects' event_ids 6.) Assemble many-to-manys 7.) Return to client Thoughts on this approach? Many thanks for reading and any advice you can give. -Dane

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  • xaml nested class path designer issue

    - by Vlad Bezden
    Hi, I have nested class public class Enums { public enum WindowModeEnum { Edit, New } } In my xaml I reference code: <Style.Triggers> <DataTrigger Binding="{Binding WindowMode}" Value="{x:Static Types1:Enums+WindowModeEnum.Edit}"> <Setter Property="Visibility" Value="Collapsed" /> </DataTrigger> </Style.Triggers> Code compiles and runs properly, however I can't open xaml code in design window. I am getting following error: Type 'Types1:Enums+WindowModeEnum' was not found. at MS.Internal.Metadata.ExposedTypes.ValueSerializers.StaticMemberDocumentValueSerializer.ConvertToDocumentValue(ITypeMetadata type, String value, IServiceProvider documentServices) at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlMarkupExtensionPropertyBase.get_Value() at MS.Internal.Design.DocumentModel.DocumentTrees.DocumentPropertyWrapper.get_Value() at MS.Internal.Design.DocumentModel.DocumentTrees.InMemory.InMemoryDocumentProperty..ctor(DocumentProperty property, InMemoryDocumentItem item) at MS.Internal.Design.DocumentModel.DocumentTrees.InMemory.InMemoryDocumentItem.SetUpItem(DocumentItem item) Same error exist in VS2008, VS2010. Does anybody has any idea, how to deal with it so I can open window in design mode. Thanks a lot. Sincerely, Vlad.

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  • How do I use Sketchflow sample data for a ListBoxItem Template at design time?

    - by Boris Nikolaevich
    I am using Expression Blend 4 and Visual Studio 2010 to create a Sketchflow prototype. I have a Sample Data collection and a ListBox that is bound to it. This displays as I would expect both at design time and at run time. However, the ListBoxItem template it just complex enough that I wanted to pull it out into its own XAML file. Even though the items still render as expected in the main ListBox where the template is used, when I open the template itself, all of the databound controls are empty. If I add a DataContext to the template, I can see and work with the populated objects while in the template, but then that local DataContext overrides the DataContext set on the listbox. A bit of code will illustrate. Start by creating a Sketchflow project (I am using Silverlight, but it should work the same for WPF), then add a project data source called SampleDataSource. Add a collection called ListData, with a single String property called Title. Here is the (scaled down) code for the main Sketchflow screen, which we'll call Main.xaml: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:DemoScreens" mc:Ignorable="d" x:Class="DemoScreens.Main" Width="800" Height="600"> <UserControl.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="ProjectDataSources.xaml"/> </ResourceDictionary.MergedDictionaries> <DataTemplate x:Key="ListBoxItemTemplate"> <local:DemoListBoxItemTemplate d:IsPrototypingComposition="True" Margin="0,0,5,0" Width="748"/> </DataTemplate> </ResourceDictionary> </UserControl.Resources> <Grid x:Name="LayoutRoot" Background="#5c87b2" DataContext="{Binding Source={StaticResource SampleDataSource}}"> <ListBox Background="White" x:Name="DemoList" Style="{StaticResource ListBox-Sketch}" Margin="20,100,20,20" ItemTemplate="{StaticResource ListBoxItemTemplate}" ItemsSource="{Binding ListData}" ScrollViewer.HorizontalScrollBarVisibility="Disabled"/> </Grid> </UserControl> You can see that it references the DemoListBoxItemTemplate, which is defined in its own DemoListBoxItemTemplate.xaml: <UserControl xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:DemoScreens" mc:Ignorable="d" x:Class="DemoScreens.DemoListBoxItemTemplate"> <Grid x:Name="LayoutRoot"> <TextBlock Text="{Binding Title}" Style="{StaticResource BasicTextBlock-Sketch}" Width="150"/> </Grid> </UserControl> Obviously, this is way simpler than my actual listbox, but it should be enough to illustrate my problem. When you open Main.xaml in the Expression designer, the list box is populated with sample data. But when you open DemoListBoxItemTemplate.xaml, there is no data context and therefore no data to display—which makes it more difficult to identify controls visually. How can I have sample data displayed when I am working with the template, while still allowing the larger set of sample data to be used for the ListBox itself?

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  • Tiered Design With Analytical Widgets - Is This Code Smell?

    - by Repo Man
    The idea I'm playing with right now is having a multi-leveled "tier" system of analytical objects which perform a certain computation on a common object and then create a new set of analytical objects depending on their outcome. The newly created analytical objects will then get their own turn to run and optionally create more analytical objects, and so on and so on. The point being that the child analytical objects will always execute after the objects that created them, which is relatively important. The whole apparatus will be called by a single thread so I'm not concerned with thread safety at the moment. As long as a certain base condition is met, I don't see this being an unstable design but I'm still a little bit queasy about it. Is this some serious code smell or should I go ahead and implement it this way? Is there a better way? Here is a sample implementation: namespace WidgetTier { public class Widget { private string _name; public string Name { get { return _name; } } private TierManager _tm; private static readonly Random random = new Random(); static Widget() { } public Widget(string name, TierManager tm) { _name = name; _tm = tm; } public void DoMyThing() { if (random.Next(1000) > 1) { _tm.Add(); } } } //NOT thread-safe! public class TierManager { private Dictionary<int, List<Widget>> _tiers; private int _tierCount = 0; private int _currentTier = -1; private int _childCount = 0; public TierManager() { _tiers = new Dictionary<int, List<Widget>>(); } public void Add() { if (_currentTier + 1 >= _tierCount) { _tierCount++; _tiers.Add(_currentTier + 1, new List<Widget>()); } _tiers[_currentTier + 1].Add(new Widget(string.Format("({0})", _childCount), this)); _childCount++; } //Dangerous? public void Sweep() { _currentTier = 0; while (_currentTier < _tierCount) //_tierCount will start at 1 but keep increasing because child objects will keep adding more tiers. { foreach (Widget w in _tiers[_currentTier]) { w.DoMyThing(); } _currentTier++; } } public void PrintAll() { for (int t = 0; t < _tierCount; t++) { Console.Write("Tier #{0}: ", t); foreach (Widget w in _tiers[t]) { Console.Write(w.Name + " "); } Console.WriteLine(); } } } class Program { static void Main(string[] args) { TierManager tm = new TierManager(); for (int c = 0; c < 10; c++) { tm.Add(); //create base widgets; } tm.Sweep(); tm.PrintAll(); Console.ReadLine(); } } }

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  • If 'Architect' is a dirty word - what's the alternative; when not everyone can actually design a goo

    - by Andras Zoltan
    Now - I'm a developer first and foremost; but whenever I sit down to work on a big project with lots of interlinking components and areas, I will forward-plan my interfaces, base classes etc as best I can - putting on my Architect hat. For a few weeks I've been doing this for a huge project - designing whole swathes of interfaces etc for a business-wide platform that we're developing. The basic structure is a couple of big projects that consists of service and data interfaces, with some basic implementations of all of these. On their own, these assemblies are useless though, as they are simply intended intended as a scaffold on which to build a business-specific implementation (we have a lot of businesses). Therefore, the design of the core platform is absolutely crucial, since consumers of the system are not intended to know which implementation they are actually using. In the past it's not worked so well, but after a few proof-of-concepts and R&D projects this new platform is now growing nicely and is already proving itself. Then somebody else gets involved in the project - he's a TDD man who sees code-level architecture as an irrelevance and is definitely from the camp that 'architect' is a dirty word - I should add that our working relationship is very good despite this :) He's open about the fact that he can't architect in advance and obviously TDD really helps him because it allows him to evolve his systems over time. That I get, and totally understand; but it means that his coding style, basically, doesn't seem to be able to honour the architecture that I've been putting in place. Now don't get me wrong - he's an awesome coder; but the other day he needed to extend one of his components (an implementation of a core interface) to bring in an extra implementation-specific dependency; and in doing so he extended the core interface as well as his implementation (he uses ReSharper), thus breaking the independence of the whole interface. When I pointed out his error to him, he was dismayed. Being test-first, all that mattered to him was that he'd made his tests pass, and just said 'well, I need that dependency, so can't we put it in?'. Of course we could put it in, but I was frustrated that he couldn't see that refactoring the generic interface to incorporate an implementation-specific feature was just wrong! But it is all very Charlie Brown to him (you know the sound the adults make when they're talking to the children) - as far as he's concerned we don't need to worry about it because we can always refactor. The problem is, the culture of test-write-refactor is all very well and good - but not when you're dealing with a platform that is going to be shared out among so many projects that you could never get them all in one place to make the refactorings work. In my opinion, sometimes you actually have to think about what you're doing, and not just let nature take its course. Am I simply fulfilling the role of Architect as a dirty word here? I believe that architecture is important and should be thought about before code gets written; unless it's a particularly small project. But when you're working in a team of people who don't think that way, or even can't think that way how can you actually get this across? Is it a case of simply making the architecture off-limits to changes by other people? I don't want to start having bloody committees just to be able to grow the system; but equally I don't want to be the only one responsible for it all. Do you think the architect role is a waste of time? Is it at odds with TDD and other practises? Can this mix of different practises be made to work, or should I just be a lot less precious (and in so doing allow a generic platform become useless!)? Or do I just lay down the law? Any ideas/experiences/views gratefully received.

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