Search Results

Search found 8467 results on 339 pages for 'map layers'.

Page 318/339 | < Previous Page | 314 315 316 317 318 319 320 321 322 323 324 325  | Next Page >

• launching mapview from main activity (button)

  - by arc

  Hi all. Going round in circles here i think. I have an activity called Locate; public class Locate extends Activity { public static String lat; public static String lon; public static String number; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.locate); final Button buttonMaps = (Button) findViewById(R.id.ButtonMaps); buttonMaps.setOnClickListener(new View.OnClickListener() { public void onClick(View v) { Toast.makeText(getBaseContext(), "Button Pressed", Toast.LENGTH_SHORT).show(); try { Intent i = new Intent(getBaseContext(), displayMap.class); i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); startActivity(i); } catch (ActivityNotFoundException e) { Toast.makeText(getBaseContext(), "Activity Not Found", Toast.LENGTH_SHORT).show(); } }}); // Toast.makeText(getBaseContext(), "lat: " + lat + " long: " + lon + " from: " + testname, Toast.LENGTH_LONG).show(); } If I make the displayMap class into a normal Activity, and just have display a toast message confirming it has loaded - then it works fine. If i do this though; public class displayMap extends MapActivity { /** Called when the activity is first created. */ public void onCreate() { setContentView(R.layout.displaymap); Toast.makeText(getBaseContext(), "Display Map", Toast.LENGTH_SHORT).show(); } @Override protected boolean isRouteDisplayed() { // TODO Auto-generated method stub return false; } } Then as soon as I click the Button, I get a force close. I have the correct 'uses-library' tag in my manifest; <application android:icon="@drawable/icon" android:label="@string/app_name"> <uses-library android:name="com.google.android.maps" /> I don't get what it just force closes everytime i try and load it. If I make this my onClick handler then it will fire up a working googlemaps/default mapview public void onClick(View v) { Toast.makeText(getBaseContext(), "Button Pressed", Toast.LENGTH_SHORT).show(); Uri uri=Uri.parse("geo:"+Locate.lat+","+Locate.lon); StartActivity(new Intent(Intent.ACTION_VIEW, uri)); } But that is not what I am trying to do, I want my own - so that I can add overlays etc to it. But it does prove that the permission are set correctly and that the lib is there. The logcat error when the app FCs is a Unexpected DEX error. Can anyone point in the right direction here?

  Read the article

• Network communication for a turn based board game

  - by randooom

  Hi all, my first question here, so please don't be to harsh if something went wrong :) I'm currently a CS student (from Germany, if this info is of any use ;) ) and we got a, free selectable, programming assignment, which we have to write in a C++/CLI Windows Forms Application. My team, two others and me, decided to go for a network-compatible port of the board game Risk. We divided the work in 3 Parts, namely UI, game logic and network. Now we're on the part where we have to get everything working together and the big question mark is, how to get the clients synchronized with each other? Our approach so far is, that each client has all information necessary to calculate and/or execute all possible actions. Actually the clients have all information available at all, aside from the game-initializing phase (add players, select map, etc.), which needs one "super-client" with some extra stuff to control things. This is the standard scenario of our approach: player performs action, the action is valid and got executed on the players client action is sent over the network action is executed on the other clients The design (i.e. no or code so far) we came up with so far, is something like the following pseudo sequence diagram. Gui, Controller and Network implement all possible actions (i.e. all actions which change data) as methods from an interface. So each part can implement the method in a way to get their job done. Example with Action(): On the player side's Client: Player-->Gui.Action() Gui-->Controller.Action() Controller-->Logic.Action (Logic.Action() == NoError)? Controller-->Network.Action() Network-->Parser.ParseAction() Network.Send(msg) On all other clients: Network.Recv(msg) Network-->Parser.Deparse(msg) Parser-->Logic.Action() Logic-->Gui.Action() The questions: Is this a viable approach to our task? Any better/easier way to this? Recommendations, critique? Our knowledge (so you can better target your answer): We are on the beginner side, in regards to programming on a somewhat larger projects with a small team. All of us have some general programming experience and basic understanding of the .Net Libraries and Windows Forms. If you need any further information, please feel free to ask.

  Read the article

• NoSQL DB for .Net document-based database (ECM)

  - by Dane

  I'm halfway through coding a basic multi-tenant SaaS ECM solution. Each client has it's own instance of the database / datastore, but the .Net app is single instance. The documents are pretty much read only (i.e. an image archive of tiffs or PDFs) I've used MSSQL so far, but then started thinking this might be viable in a NoSQL DB (e.g. MongoDB, CouchDB). The basic premise is that it stores documents, each with their own particular indexes. Each tenant can have multiple document types. e.g. One tenant might have an invoice type, which has Customer ID, Invoice Number and Invoice Date. Another tenant might have an application form, which has Member Number, Application Number, Member Name, and Application Date. So far I've used the old method which Sharepoint (used?) to use, and created a document table which has int_field_1, int_field_2, date_field_1, date_field_2, etc. Then, I've got a "mapping" table which stores the customer specific index name, and the database field that will map to. I've avoided the key-value pair model in the DB due to volume of documents. This way, we can support multiple document types in the one table, and get reasonably high performance out of it, and allow for custom document type searches (i.e. user selects a document type, then they're presented with a list of search fields). However, a NoSQL DB might make this a lot simpler, as I don't need to worry about denormalizing the document. However, I've just got concerns about the rest of the data around a document. We store an "action history" against the document. This tracks views, whether someone emails the document from within the system, and other "future" functionality (e.g. faxing). We have control over the document load process, so we can manipulate the data however it needs to be to get it in the document store (e.g. assign unique IDs). Users will not be adding in their own documents, so we shouldn't need to worry about ACID compliance, as the documents are relatively static. So, my questions I guess : Is a NoSQL DB a good fit Is MongoDB the best for Asp.Net (I saw Raven and Velocity, but they're still kinda beta) Can I store a key for each document, and then store the action history in a MSSQL DB with this key? I don't need to do joins, it would be if a person clicks "View History" against a document. How would performance compare between the two (NoSQL DB vs denormalized "document" table) Volumes would be up to 200,000 new documents per month for a single tenant. My current scaling plan with the SQL DB involves moving the SQL DB into a cluster when certain thresholds are reached, and then reviewing partitioning and indexing structures.

  Read the article

• Animated Ellipse

  - by user287798

  Hi, i need someone to help me. I need a xaml with animated ellipses like the ones shown here:http://www.telerik.com/products/silverlight/chart.aspx They are to act as hotspot indicators on my map. What i have below is a xaml that i was trying to do but the circles don't center and have no fed-in/fade-out effect. May somebody help me please. Thanks Sam 1 <UserControl 2 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 3 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 4 x:Class="SilverlightApplication3.MainPage" 5 Width="640" Height="480"> 6 7 8 <Canvas> 9 10 <Canvas.Triggers> 11 <EventTrigger RoutedEvent="Canvas.Loaded"> 12 <EventTrigger.Actions> 13 <BeginStoryboard> 14 <Storyboard > 15 <DoubleAnimation RepeatBehavior="Forever" 16 Storyboard.TargetName="Pt1" 17 Storyboard.TargetProperty="ScaleX" 18 From="1" 19 To="0.3" 20 Duration="0:0:5" /> 21 </Storyboard> 22 </BeginStoryboard> 23 24 <BeginStoryboard> 25 <Storyboard> 26 <DoubleAnimation RepeatBehavior="Forever" 27 Storyboard.TargetName="Pt1" 28 Storyboard.TargetProperty="ScaleY" 29 From="1" 30 To="0.3" 31 Duration="0:0:5" /> 32 </Storyboard> 33 </BeginStoryboard> 34 <!--<BeginStoryboard> 35 <Storyboard > 36 <DoubleAnimation RepeatBehavior="Forever" 37 Storyboard.TargetName="rect_Copy" 38 Storyboard.TargetProperty="Width" 39 From="30" 40 To="100" 41 Duration="0:0:5" /> 42 </Storyboard> 43 </BeginStoryboard> 44 45 <BeginStoryboard> 46 <Storyboard> 47 <DoubleAnimation RepeatBehavior="Forever" 48 Storyboard.TargetName="rect_Copy" 49 Storyboard.TargetProperty="Height" 50 From="30" 51 To="100" 52 Duration="0:0:5" /> 53 </Storyboard> 54 </BeginStoryboard>--> 55 </EventTrigger.Actions> 56 </EventTrigger> 57 </Canvas.Triggers> 58 59 60 <Ellipse x:Name="rect" Stroke="Green" Width="100" Height="100" Canvas.Left="30" 61 Canvas.Top="29"> 62 <Ellipse.RenderTransform> 63 <ScaleTransform x:Name="Pt1" ScaleX="1" ScaleY="1"/> 64 </Ellipse.RenderTransform> 65 66 </Ellipse> 67 <Ellipse x:Name="rect_Copy" 68 Stroke="Green" 69 Width="30" 70 Height="30" 71 Canvas.Left="65" 72 Canvas.Top="64"/> 73 74 </Canvas> 75 </UserControl>

  Read the article

• JQGrid and JQuery Autocomplete

  - by Neff

  When implementing JQGrid 4.3.0, Jquery 1.6.2, and JQuery UI 1.8.16 Ive come across an issue with the Inline edit. When the inline edit is activated, some of the elements get assigned an auto complete. When the inline edit is canceld or saved, the auto complete does not always go away (selecting text by double clicking it then hitting delete, then hitting escape to exit row edit). Leaving the auto complete controls in edit mode when the row is no longer considered in edit mode. Perhaps you can tell me if there is a problem with the initialization or if I you are aware of an event post-"afterrestorefunc" that the fields can be returned to their "original" state. Original state being displayed as data in the JQGrid row. I've tried removing the DOM after row close, .remove() and .empty(): ... "afterrestorefunc": function(){ $('.ui-autocomplete-input').remove(); } ... but that causes other issues, such as the jqgrid is not able to find the cell when serializing the row for data or edit, and requires a refresh of the page, not just jqgrid, to be able to once again see the data from that row. Auto complete functionality for the element is created on the double click of the row: function CreateCustomSearchElement(value, options, selectiontype) { ... var el; el = document.createElement("input"); ... $(el).autocomplete({ source: function (request, response) { $.ajax({ url: '<%=ResolveUrl("~/Services/AutoCompleteService.asmx/GetAutoCompleteResponse") %>', data: "{ 'prefixText': '" + request.term + "', 'contextKey': '" + options.name + "'}", dataType: "json", type: "POST", contentType: "application/json; charset=utf-8", success: function (data) { response($.map(data.d, function (item) { return { label: Trim(item), value: Trim(item), searchVal: Trim(item) } })) } }); }, select: function (e, item) { //Select is on the event of selection where the value and label have already been determined. }, minLength: 1, change: function (event, ui) { //if the active element was not the search button //... } }).keyup(function (e) { if (e.keyCode == 8 || e.keyCode == 46) { //If the user hits backspace or delete, check the value of the textbox before setting the searchValue //... } }).keydown(function (e) { //if keycode is enter key and there is a value, you need to validate the data through select or change(onblur) if (e.keyCode == '13' && ($(el).val())) { return false; } if (e.keyCode == '220') { return false } }); } Other Sources: http://www.trirand.com/jqgridwiki/doku.php?id=wiki:inline_editing http://api.jqueryui.com/autocomplete/ Update: I tried only creating the autocomplete when the element was focused, and removing it when onblur. That did not resolve the issue either. It seems to just need the autocomplete dropdown to be triggered.

  Read the article

• PC powers off at random times

  - by Timo Huovinen

  Short Version After experiencing some problems with Mobo batteries my PC started to power off at random times, the power off is instant and sudden and does not restart afterwards, need help figuring out the cause. Facts: Powers off when PC is playing games Powers off when PC is idle Powers off when PC is in safe mode Powers off when PC is in BIOS Powers off when PC is booted through a Windows installation USB Replaced the motherboard battery several times Replaced the 650W PSU with a 750W PSU Replaced the RAM Swapped the RAM between slots Re-applied thermal paste to the CPU Checked if the motherboard touches the case Nothing is overclocked PC Specs PC specs: OS: Windows 7 Ultimate SP1 RAM: klingston 1333MHz 4GB stick CPU: AMD Phenom II x4 955 Mobo: Gigabyte 88GMA-UD2H rev 2.2 Motherboard battery: CR2032 3v HDD: 500GB Seagate ST3500418AS ATA Device Graphics: ATI/AMD Radeon HD 6870 Very Long version Around 10 months ago I built a brand new gaming PC. Around 6 months ago it's time setting in windows started resetting to the year 2010. I swapped the Motherboard battery for a new one of the exact same size and shape and voltage, and the problems disappeared...for around 2 weeks. Then the same problem happened again, time gets reset, I swapped the battery again, and the problem was gone for good and everything was great for about 3 months.. then another problem started happening, the PC started to power off suddenly and without warning at completely random times, sometimes the PC works for and hour, sometimes 5 minutes. So I read on the forums that it might be either the PSU or the motherboard Battery or RAM or HDD or the Graphics card or the CPU or the motherboard or the drivers or a Virus or Grounding issues, or something short circuiting, basically it can be anything... I spent some days researching, and decided to remove the possibility of a virus. I reset the CMOS, cleared all BIOS settings and reinstalled windows 7 after a full format of the HDD, but the random power off kept happening. I then disabled the restart on error option in windows and looked at the event log for error events, but they did not help me figure out the problem. Network list service depends on network location awareness the dependency group failed to start Source Kernel Power Event 41 Task Category 63 Source Disk Event ID 11 Task Category None The driver detected a controller error on device disk I took apart the PC, every little piece, re-applied some expensive thermal paste to the CPU, and double checked that none of the pieces are touching the PC case. The problem was gone, the PC no longer powered off randomly I re-attached the graphics card and all was good for 4 months... then the power off problem appeared again, but was happening at high intervals, the PC would shutdown once in 2 days on average, at random points in time, sometimes when it's idle all day long, sometimes when it's running CRYSIS 2. I checked the CPU temperature, because I know that AMD CPU's have a built in protection mechanism that switches off the PC if the CPU gets too hot, and the Temp was 50C system temp, and 45C CPU after running the PC all day long (I did not do tests to see if there are any temperature spikes, don't know how to do them) Originally the PSU that powered the PC was 650Watts and had one 4 pin cable to power the CPU, I replaced it with a new 750Watts PSU which has two 4 pin cables for the CPU, but the problem remained. I removed the graphics card and let the motherboard use the built in one, but the PC kept suddenly powering off at random times. I took apart the PC completely again, and re-applied thermal paste to the CPU, added lots of insulation, and checked for any type of short-circuit possibility again and again, but the problem remained. The problem was like that for some months. I replaced the Battery a couple of times over the time, changed lots of options in windows, and tried everything I could, but it kept powering off, so I stopped using the PC as much as I used to, just living with the random power offs from time to time, until a couple of days ago, when the power off happens almost immediately after powering on the PC. I replaced the RAM with a brand new one, but that did not help. Took apart the PC again, checked for anything anywhere that might cause it, found some small scratches on the very edge of the motherboard to the left of the PCI express x16 slot. This might cause the problem, I thought, but the scratch looks very superficial, not deep at all, and if the scratch did harm the motherboard, wouldn't it cause it to not start at all? And why did it start to power off a while ago, and then suddenly stop powering off? The scratches could not have vanished??? did chkdsk \d but it powered off when it was at 75% I removed the hard disks, the graphics card, while I fiddled with the BIOS settings, and suddenly the PC shut down while I was looking at the BIOS version. This makes me realize, it is not caused by: HDD, Windows, Drivers or the Graphics card I cleared the CMOS again, updated the BIOS from F5 to F6f beta, but that did not help, it might even seem that the PC powers off even sooner. The shutdown even happened to me while I booted through a windows 7 installation USB and was in the repair console. I removed one of the cables powering the CPU, now only one 4pin cable powers it, and it worked for 30mins after doing that, which makes me think that it's the CPU overheating, and because it gets less power, it overheats slower? The things that I am still considering: CPU overheating (does not seem to overheat, maybe false readings?) Motherboard short circuiting (faulty motherboard?) I desperately need some advice in what is faulty, is it a faulty Motherboard or an overheating CPU? or maybe something else? I have been breaking my head over this problem over a span of 6 months. I'm not sure if this is a good place to ask this question, if it is not, then tell me where I can get some experienced help. More info I have also discovered a mysterious piece that seems to have fallen out of the motherboard i119.photobucket.com/albums/o126/yurikolovsky/strangepiece.jpg What is it? Looks like each time that it powers off the datetime gets reset I also found another forum post tomshardware.co.uk/forum/… except I don't have Integrated PeripheralsUSB Keyboard Function option in BIOS :S Comments summary (asked by Random moderator) Q. tell me, if the computer restarts, is it immediately? Does it take a second and then restarts? Do you see (BSOD) or hear (PSU, short circuit) any suspicious when it happens? After reading trough it, it remains the mainboard that is faulty. – JohannesM A. Immediate power off, all the fans stop instantly, all the light turn off instantly, no sound or anything, and it remains off until I turn it back on. Thanks for the feedback, faulty motherboard is what I fear. Q. Try stress-testing the system with Prime95 and see if errors or shutdowns occur when the CPU is under full load. – speakr A. Prime95 heat stress test peaked CPU heat at 60C after 5mins, it powered off after 30mins of testing in the middle of the test with no errors, Prime95 Heat test or the stress-testing with low RAM usage (small or in-place FFTs) do not report errors while testing for 10-60 mins. The power off does not seem like it is affected by Prime95 at all Makes me wonder if it's a CPU or Motherboard issue at all. Q. I had similar random/intermittent problems with my old board. It gave one of a few different symptoms: keyboard and/or mouse would die and/or the RAM wouldn't work and/or it would shut down. It was in bad shape. One problems was that my old PSU had literally burned the connector on it (browned around the pins), another was that a broken lead inside the layers of the PCB would work sometimes if it happened to be hot or if I bent the board—by jamming a hunk of wood behind it. I managed to keep the board alive for several years, but eventually nothing I did would make it work correctly anymore. – Synetech A. I will try that as the last resort, ok? ;) Q. Have you tried a different power cord, surge protector, outlet (on a different circuit). It's worth a shot just to ensure it's not subpar wiring or a week circuit (dips in power may cause shutdown if the PSU can't pull enough juice from the wall). – Kyle A. yes, I attached the PC to an entirely different outlet on a different circuit and the problem persists. After connecting it to a different outlet after starting the PC it gave me 3 long beeps and 1 short one, then the PC immediately proceeded to boot up normally. Q. Re-check your mainboard manual and all PSU connections to your mainboard to be sure that nothing is missing (e.g. 12V ATX 4-pin/6-pin connector). If you can provoke shutdowns with Prime95, then consider buying new hardware -- a stable system should run Prime95 for 24h without any errors. Prime95 mentions errors in the log when they occur and gives a summary after the stress test was stopped manually (e.g. "0 errors, 0 warnings", if all is fine) – speakr A. Re-checked, there are no more PSU connectors that I can physically connect, except the one ATX 4-pin (there are 2 that power the CPU) that I disconnected on purpose, I have reconnected it but the problem persists. Q. With one PC I had a short curcuit. The power button on the front plate had its cables soldered, but not isolated, and the contacts were very close to the metal case. A heavier touch was enough to cause a shutdown. The PC's vibration could be enough – ott-- A. yes, it seems to switch off with even the lightest touch, I switched on the PC, then pulled out the front panel power cable that connects to the motherboard so the power button does not work anymore, after 5 mins of working like that, with the power button completely disconnected, just sitting idle, the PC powered off again, I don't think it's the power button. Q. I wonder if you dare to operate components without the case, that is remove motherboard, power, disk ( just put the motherboard on a wooden desk). Don't bend the adapters when running like that. – ott-- A. yes, I do dare to do that, but only tomorrow, too tired/late right now.

  Read the article

• Putting update logic in your migrations

  - by Daniel Abrahamsson

  A couple of times I've been in the situation where I've wanted to refactor the design of some model and have ended up putting update logic in migrations. However, as far as I've understood, this is not good practice (especially since you are encouraged to use your schema file for deployment, and not your migrations). How do you deal with these kind of problems? To clearify what I mean, say I have a User model. Since I thought there would only be two kinds of users, namely a "normal" user and an administrator, I chose to use a simple boolean field telling whether the user was an adminstrator or not. However, after I while I figured I needed some third kind of user, perhaps a moderator or something similar. In this case I add a UserType model (and the corresponding migration), and a second migration for removing the "admin" flag from the user table. And here comes the problem. In the "add_user_type_to_users" migration I have to map the admin flag value to a user type. Additionally, in order to do this, the user types have to exist, meaning I can not use the seeds file, but rather create the user types in the migration (also considered bad practice). Here comes some fictional code representing the situation: class CreateUserTypes < ActiveRecord::Migration def self.up create_table :user_types do |t| t.string :name, :nil => false, :unique => true end #Create basic types (can not put in seed, because of future migration dependency) UserType.create!(:name => "BASIC") UserType.create!(:name => "MODERATOR") UserType.create!(:name => "ADMINISTRATOR") end def self.down drop_table :user_types end end class AddTypeIdToUsers < ActiveRecord::Migration def self.up add_column :users, :type_id, :integer #Determine type via the admin flag basic = UserType.find_by_name("BASIC") admin = UserType.find_by_name("ADMINISTRATOR") User.all.each {|u| u.update_attribute(:type_id, (u.admin?) ? admin.id : basic.id)} #Remove the admin flag remove_column :users, :admin #Add foreign key execute "alter table users add constraint fk_user_type_id foreign key (type_id) references user_types (id)" end def self.down #Re-add the admin flag add_column :users, :admin, :boolean, :default => false #Reset the admin flag (this is the problematic update code) admin = UserType.find_by_name("ADMINISTRATOR") execute "update users set admin=true where type_id=#{admin.id}" #Remove foreign key constraint execute "alter table users drop foreign key fk_user_type_id" #Drop the type_id column remove_column :users, :type_id end end As you can see there are two problematic parts. First the row creation part in the first model, which is necessary if I would like to run all migrations in a row, then the "update" part in the second migration that maps the "admin" column to the "type_id" column. Any advice?

  Read the article

• Spring AOP pointcut that matches annotation on interface

  - by seanizer

  Hello, this is my first post here, so I apologize in advance for any stupidity on my side. I have a service class implemented in Java 6 / Spring 3 that needs an annotation to restrict access by role. I have defined an annotation called RequiredPermission that has as its value attribute one or more values from an enum called OperationType: public @interface RequiredPermission { /** * One or more {@link OperationType}s that map to the permissions required * to execute this method. * * @return */ OperationType[] value();} public enum OperationType { TYPE1, TYPE2; } package com.mycompany.myservice; public interface MyService{ @RequiredPermission(OperationType.TYPE1) void myMethod( MyParameterObject obj ); } package com.mycompany.myserviceimpl; public class MyServiceImpl implements MyService{ public myMethod( MyParameterObject obj ){ // do stuff here } } I also have the following aspect definition: /** * Security advice around methods that are annotated with * {@link RequiredPermission}. * * @param pjp * @param param * @param requiredPermission * @return * @throws Throwable */ @Around(value = "execution(public *" + " com.mycompany.myserviceimpl.*(..))" + " && args(param)" + // parameter object " && @annotation( requiredPermission )" // permission annotation , argNames = "param,requiredPermission") public Object processRequest(final ProceedingJoinPoint pjp, final MyParameterObject param, final RequiredPermission requiredPermission) throws Throwable { if(userService.userHasRoles(param.getUsername(),requiredPermission.values()){ return pjp.proceed(); }else{ throw new SorryButYouAreNotAllowedToDoThatException( param.getUsername(),requiredPermission.value()); } } The parameter object contains a user name and I want to look up the required role for the user before allowing access to the method. When I put the annotation on the method in MyServiceImpl, everything works just fine, the pointcut is matched and the aspect kicks in. However, I believe the annotation is part of the service contract and should be published with the interface in a separate API package. And obviously, I would not like to put the annotation on both service definition and implementation (DRY). I know there are cases in Spring AOP where aspects are triggered by annotations one interface methods (e.g. Transactional). Is there a special syntax here or is it just plain impossible out of the box. PS: I have not posted my spring config, as it seems to be working just fine. And no, those are neither my original class nor method names. Thanks in advance, Sean PPS: Actually, here is the relevant part of my spring config: <aop:aspectj-autoproxy proxy-target-class="false" /> <bean class="com.mycompany.aspect.MyAspect"> <property name="userService" ref="userService" /> </bean>

  Read the article

• Insertions into Zipper trees on XML files in Clojure

  - by ivar

  I'm confused as how to idiomatically change a xml tree accessed through clojure.contrib's zip-filter.xml. Should be trying to do this at all, or is there a better way? Say that I have some dummy xml file "itemdb.xml" like this: <itemlist> <item id="1"> <name>John</name> <desc>Works near here.</desc> </item> <item id="2"> <name>Sally</name> <desc>Owner of pet store.</desc> </item> </itemlist> And I have some code: (require '[clojure.zip :as zip] '[clojure.contrib.duck-streams :as ds] '[clojure.contrib.lazy-xml :as lxml] '[clojure.contrib.zip-filter.xml :as zf]) (def db (ref (zip/xml-zip (lxml/parse-trim (java.io.File. "itemdb.xml"))))) ;; Test that we can traverse and parse. (doall (map #(print (format "%10s: %s\n" (apply str (zf/xml-> % :name zf/text)) (apply str (zf/xml-> % :desc zf/text)))) (zf/xml-> @db :item))) ;; I assume something like this is needed to make the xml tags (defn create-item [name desc] {:tag :item :attrs {:id "3"} :contents (list {:tag :name :attrs {} :contents (list name)} {:tag :desc :attrs {} :contents (list desc)})}) (def fred-item (create-item "Fred" "Green-haired astrophysicist.")) ;; This disturbs the structure somehow (defn append-item [xmldb item] (zip/insert-right (-> xmldb zip/down zip/rightmost) item)) ;; I want to do something more like this (defn append-item2 [xmldb item] (zip/insert-right (zip/rightmost (zf/xml-> xmldb :item)) item)) (dosync (alter db append-item2 fred-item)) ;; Save this simple xml file with some added stuff. (ds/spit "appended-itemdb.xml" (with-out-str (lxml/emit (zip/root @db) :pad true))) I am unclear about how to use the clojure.zip functions appropriately in this case, and how that interacts with zip-filter. If you spot anything particularly weird in this small example, please point it out.

  Read the article

• NHibernate - I have many, but I only want one!

  - by MartinF

  Hello, I have a User which can have many Emails. This is mapped through a List collection (exposed by IEnumerable Emails on the User). For each User one of the Emails will be the Primary one ("Boolean IsPrimary" property on Email). How can I get the primary Email from User without NHibernate loads every email for the User ? I have the following two entities, with a corresponding table for each public class User { public virtual int Id { get; set; } public virtual IEnumerable<Email> Emails { get; set; } // public virtual Email PrimaryEmail { get; set; } - Possible somehow ? } public class Email { public virtual int Id { get; set; } public virtual String Address { get; set; } public virtual Boolean IsPrimary { get; set; } public virtual User User { get; set; } } Can I map a "Email PrimaryEmail" property etc. on the User to the Email which have "IsPrimary=1" set somehow ? Maybe using a Sql Formula ? a View ? a One-To-One relationship ? or another way ? It should be possible to change the primary email to be one of the other emails, so i would like to keep them all in 1 table and just change the IsPrimary property. Using a Sql Formula, is it be possible to keep the "PrimaryEmail" property on the User up-to-date, if I set the IsPrimary property on the current primary email to false, and then afterwards set the PrimaryEmail property to the email which should be the new primary email and set IsPrimary to true ? Will NHibernate track changes on the "old/current" primary Email loaded by the Sql Formula ? What about the 1 level cache and the 2 level cache when using SqlFormula ? I dont know if it could work by using a View ? Then i guess the Email could be mapped like a Component ? Will it work when updating the Email data when loaded from the View ? Is there a better way ? As I have a bi-directional relationship between User and Email I could in many cases of course query the primary Email and then use the "User" property on the Email to get the User (instead of the other way around - going from User to the primary Email) Hope someone can help ?

  Read the article

• Xcache - No different after using it

  - by Charles Yeung

  Hi I have installed Xcache in my site(using xampp), I have tested more then 10 times on several page and the result is same as default(no any cache installed), is it something wrong with the configure? Updated [xcache-common] ;; install as zend extension (recommended), normally "$extension_dir/xcache.so" zend_extension = /usr/local/lib/php/extensions/non-debug-non-zts-xxx/xcache.so zend_extension_ts = /usr/local/lib/php/extensions/non-debug-zts-xxx/xcache.so ;; For windows users, replace xcache.so with php_xcache.dll zend_extension_ts = C:\xampp\php\ext\php_xcache.dll ;; or install as extension, make sure your extension_dir setting is correct ; extension = xcache.so ;; or win32: ; extension = php_xcache.dll [xcache.admin] xcache.admin.enable_auth = On xcache.admin.user = "mOo" ; xcache.admin.pass = md5($your_password) xcache.admin.pass = "" [xcache] ; ini only settings, all the values here is default unless explained ; select low level shm/allocator scheme implemenation xcache.shm_scheme = "mmap" ; to disable: xcache.size=0 ; to enable : xcache.size=64M etc (any size > 0) and your system mmap allows xcache.size = 60M ; set to cpu count (cat /proc/cpuinfo |grep -c processor) xcache.count = 1 ; just a hash hints, you can always store count(items) > slots xcache.slots = 8K ; ttl of the cache item, 0=forever xcache.ttl = 0 ; interval of gc scanning expired items, 0=no scan, other values is in seconds xcache.gc_interval = 0 ; same as aboves but for variable cache xcache.var_size = 4M xcache.var_count = 1 xcache.var_slots = 8K ; default ttl xcache.var_ttl = 0 xcache.var_maxttl = 0 xcache.var_gc_interval = 300 xcache.test = Off ; N/A for /dev/zero xcache.readonly_protection = Off ; for *nix, xcache.mmap_path is a file path, not directory. ; Use something like "/tmp/xcache" if you want to turn on ReadonlyProtection ; 2 group of php won't share the same /tmp/xcache ; for win32, xcache.mmap_path=anonymous map name, not file path xcache.mmap_path = "/dev/zero" ; leave it blank(disabled) or "/tmp/phpcore/" ; make sure it's writable by php (without checking open_basedir) xcache.coredump_directory = "" ; per request settings xcache.cacher = On xcache.stat = On xcache.optimizer = Off [xcache.coverager] ; per request settings ; enable coverage data collecting for xcache.coveragedump_directory and xcache_coverager_start/stop/get/clean() functions (will hurt executing performance) xcache.coverager = Off ; ini only settings ; make sure it's readable (care open_basedir) by coverage viewer script ; requires xcache.coverager=On xcache.coveragedump_directory = "" Thanks you

  Read the article

• Mapscript queryByPoint return no results

  - by lucian.jp

  I have a dynamically generated mapfile made with c# mapscript that is defined like: MAP EXTENT 5.91828 45.63552 5.92346 45.65051 IMAGECOLOR 192 192 192 IMAGETYPE png SIZE 256 256 STATUS ON TRANSPARENT TRUE UNITS METERS NAME "GMAP_TILE" OUTPUTFORMAT NAME "png" MIMETYPE "image/png" DRIVER "GD/PNG" EXTENSION "png" IMAGEMODE "PC256" TRANSPARENT TRUE END SYMBOL NAME "circle" TYPE ELLIPSE FILLED TRUE POINTS 1 1 END END SYMBOL NAME ">" TYPE TRUETYPE ANTIALIAS TRUE CHARACTER ">" GAP -20 FONT "arial" POSITION CC END PROJECTION "proj=merc" "a=6378137" "b=6378137" "lat_ts=0.0" "lon_0=0.0" "x_0=0.0" "y_0=0" "units=m" "k=1.0" "nadgrids=@null" END LEGEND IMAGECOLOR 255 255 255 KEYSIZE 20 10 KEYSPACING 5 5 LABEL SIZE MEDIUM TYPE BITMAP BUFFER 0 COLOR 0 0 0 FORCE FALSE MINDISTANCE -1 MINFEATURESIZE -1 OFFSET 0 0 PARTIALS TRUE END POSITION LL STATUS OFF END QUERYMAP COLOR 255 255 0 SIZE -1 -1 STATUS ON STYLE HILITE END SCALEBAR ALIGN CENTER COLOR 0 0 0 IMAGECOLOR 255 255 255 INTERVALS 4 LABEL SIZE MEDIUM TYPE BITMAP BUFFER 0 COLOR 0 0 0 FORCE FALSE MINDISTANCE -1 MINFEATURESIZE -1 OFFSET 0 0 PARTIALS TRUE END POSITION LL SIZE 200 3 STATUS OFF STYLE 0 UNITS MILES END WEB IMAGEPATH "" IMAGEURL "" QUERYFORMAT text/html LEGENDFORMAT text/html BROWSEFORMAT text/html END LAYER NAME "Troncons" PROJECTION "proj=longlat" "ellps=WGS84" "datum=WGS84" END STATUS DEFAULT TEMPLATE "nofile.html" TOLERANCE 100 TOLERANCEUNITS METERS TYPE LINE UNITS METERS CLASS NAME "Troncons" STYLE ANGLE 360 COLOR 0 0 255 SIZE 5 SYMBOL "circle" WIDTH 5 END STYLE ANGLE 360 COLOR 0 0 0 SIZE 12 SYMBOL ">" WIDTH 1 END END FEATURE POINTS 5.91828 45.63552 5.91876 45.63611 5.91898 45.6364 5.91936 45.63701 5.91952 45.63731 5.91968 45.63762 5.91993 45.63825 5.92003 45.63856 5.92018 45.63919 5.92028 45.63983 5.92031 45.64014 5.92033 45.64046 5.92034 45.64077 5.92034 45.64108 5.92034 45.64171 5.92035 45.64234 5.92035 45.6428 5.92037 45.6433 5.9204 45.64394 5.92046 45.64458 5.92056 45.64522 5.92062 45.64554 5.92069 45.64586 5.92077 45.64617 5.92097 45.64679 5.92122 45.64739 5.92136 45.64769 5.92169 45.64828 5.92207 45.64886 5.92228 45.64914 5.92272 45.64969 5.92321 45.65023 5.92346 45.65051 END END END END I try to queryByPoint to retreive the index of the shape clciked near. In the code below I made a specific test function with fixed point instead of points passed by parameter so I am sure the point I use is actually part of a feature. In my case I use the first point of the only feature contained in mapfile. public string GetTronconId() { //_map is my dynamically created mapObj if (_map != null) for (int i = 0; i < _map.numlayers; i++) { layerObj layer = _map.getLayer(i); // Code never pass this point if (layer.queryByPoint(_map, new pointObj(5.91898, 45.6364, 0, 0), (int) MS_QUERY_MODE.MS_QUERY_MULTIPLE, 100) == (int) MS_RETURN_VALUE.MS_SUCCESS) { int numresults = layer.getNumResults(); if (numresults != 0) { layer.open(); for (int j = 0; j < numresults; j++) { resultCacheMemberObj resultat = layer.getResult(j); shapeObj shape = null; if (layer.getShape(shape, resultat.tileindex, resultat.shapeindex) == (int) MS_RETURN_VALUE.MS_SUCCESS) return shape.getValue(0); } } } } return null; } I have a dummy TEMPLATE set, I do not eveen have to use the tolerance since the point is derectly in a shape, but the queryByPoint keep returning me MS_FAILURE. From my searches on the web everything seem to be OK. Any idea?

  Read the article

• How to do an fetch request with expressions like this on the iPhone?

  - by dontWatchMyProfile

  The documentation has an example on how to retrieve simple values only, rather than managed objects. This remembers a lot SQL using aliases and functions to only retrieve calculated values. So, actually pretty geeky stuff. To get the minimum date from a bunch of records, this is used on the mac: NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:context]; [request setEntity:entity]; // Specify that the request should return dictionaries. [request setResultType:NSDictionaryResultType]; // Create an expression for the key path. NSExpression *keyPathExpression = [NSExpression expressionForKeyPath:@"creationDate"]; // Create an expression to represent the minimum value at the key path 'creationDate' NSExpression *minExpression = [NSExpression expressionForFunction:@"min:" arguments:[NSArray arrayWithObject:keyPathExpression]]; // Create an expression description using the minExpression and returning a date. NSExpressionDescription *expressionDescription = [[NSExpressionDescription alloc] init]; // The name is the key that will be used in the dictionary for the return value. [expressionDescription setName:@"minDate"]; [expressionDescription setExpression:minExpression]; [expressionDescription setExpressionResultType:NSDateAttributeType]; // Set the request's properties to fetch just the property represented by the expressions. [request setPropertiesToFetch:[NSArray arrayWithObject:expressionDescription]]; // Execute the fetch. NSError *error; NSArray *objects = [managedObjectContext executeFetchRequest:request error:&error]; if (objects == nil) { // Handle the error. } else { if ([objects count] > 0) { NSLog(@"Minimum date: %@", [[objects objectAtIndex:0] valueForKey:@"minDate"]; } } [expressionDescription release]; [request release]; Nice, I though - but having a deep look into NSExpression -expressionForFunction:arguments: it turns out that iPhone OS does NOT support the min: function. Well, probably there's a nifty way to use an own function for this kind of stuff on the iPhone as well? Because on thing I'm already worrying about is, how I'm gonna sort a table based on the calculated distance of targets on a map (location-based stuff).

  Read the article

• Where to put default-servlet-handler in Spring MVC configuration

  - by gigadot

  In my web.xml, the default servlet mapping, i.e. /, is mapped to Spring dispatcher. In my Spring dispatcher configuration, I have DefaultAnnotationHandlerMapping, ControllerClassNameHandlerMapping and AnnotationMethodHandlerAdapter which allows me to map url to controllers either by its class name or its @Requestmapping annotation. However, there are some static resources under the web root which I also want spring dispatcher to serve using default servlet. According to Spring documentation, this can be done using <mvc:default-servlet-handler/> tag. In the configuration below, there are 4 candidate locations that I marked which are possible to insert this tag. Inserting the tag in different location causes the dispatcher to behave differently as following : Case 1 : If I insert it at location 1, the dispatcher will no longer be able to handle mapping by the @RequestMapping and controller class name but it will be serving the static content normally. Cas 2, 3 : It will be able to handle mapping by the @RequestMapping and controller class name as well as serving the static content if other mapping cannot be done successfully. Case 4 : It will not be able to serve the static contents. Therefore, Case 2 and 3 are desirable .According to Spring documentation, this tag configures a handler which precedence order is given to lowest so why the position matters? and Which is the best position to put this tag? <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <context:annotation-config/> <context:component-scan base-package="webapp.controller"/> <!-- Location 1 --> <!-- Enable annotation-based controllers using @Controller annotations --> <bean id="annotationUrlMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/> <!-- Location 2 --> <bean id="controllerClassNameHandlerMapping" class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"/> <!-- Location 3 --> <bean id="annotationMethodHandlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/> <!-- Location 4 --> <mvc:default-servlet-handler/> <!-- All views are JSPs loaded from /WEB-INF/jsp --> <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> </beans>

  Read the article

• Mapping two tables 0..n in Hibernate

  - by simon

  I have a table Users CREATE TABLE "USERS" ( "ID" NUMBER NOT NULL , "LOGINNAME" VARCHAR2 (150) NOT NULL ) and I have a second table SpecialUsers. No UserId can occur twice in the SpecialUsers table, and only a small subset of the ids of users in the Users table are contained in the SpecialUsers table. CREATE TABLE "SPECIALUSERS" ( "USERID" NUMBER NOT NULL, CONSTRAINT "PK_SPECIALUSERS" PRIMARY KEY ("USERID") ) ALTER TABLE "SPECIALUSERS" ADD CONSTRAINT "FK_SPECIALUSERS_USERID" FOREIGN KEY ("USERID") REFERENCES "USERS" ("ID") / Mapping the Users table in Hibernate works ok <hibernate-mapping package="com.initech.domain"> <class name="com.initech.User" table="USERS"> <id name="id" column="ID" type="java.lang.Long"> <meta attribute="use-in-tostring">true</meta> <generator class="sequence"> <param name="sequence">SEQ_USERS_ID</param> </generator> </id> <property name="loginName" column="LOGINNAME" type="java.lang.String" not-null="true"> <meta attribute="use-in-tostring">true</meta> </property> </class> </hibernate-mapping> But I'm struggling in creating the mapping for the SpecialUsers table. All the examples (e.g. in Hibernate documentation) in Internet I found don't have this type of self-reference. I tried a mapping like this: <hibernate-mapping package="com.initech.domain"> <class name="com.initech.User" table="SPECIALUSERS"> <id name="id" column="USERID"> <meta attribute="use-in-tostring">true</meta> <generator class="foreign"> <param name="property">user</param> </generator> </id> <one-to-one name="user" class="User"/> </class> </hibernate-mapping> but got the error Invocation of init method failed; nested exception is org.hibernate.DuplicateMappingException: Duplicate class/entity mapping com.initech.User How should I map the SpecialUsers table? What I need on the application level is a list of the User objects contained in the SpecialUsers table.

  Read the article

• FluentNhibernate many-to-many mapping - resolving record is not inserted

  - by Dmitriy Nagirnyak

  Hi, I have a many-to-many mapping defined (only relevant fields included): // MODEL: public class User : IPersistentObject { public User() { Permissions = new HashedSet<Permission>(); } public virtual int Id { get; protected set; } public virtual ISet<Permission> Permissions { get; set; } } public class Permission : IPersistentObject { public Permission() { } public virtual int Id { get; set; } } // MAPPING: public class UserMap : ClassMap<User> { public UserMap() { Id(x => x.Id); HasManyToMany(x => x.Permissions).Cascade.All().AsSet(); } } public class PermissionMap : ClassMap<Permission> { public PermissionMap() { Id(x => x.Id).GeneratedBy.Assigned(); Map(x => x.Description); } } The following test fails as there is no record inserted into User_Permission table: [Test] public void AddingANewUserPrivilegeShouldSaveIt() { var p1 = new Permission { Id = 123, Description = "p1" }; Session.Save(p1); var u = new User { Email = "[email protected]" }; u.Permissions.Add(p1); Session.Save(u); var userId = u.Id; Session.Evict(u); Session.Get<User>(userId).Permissions.Should().Not.Be.Empty(); } The SQL executed is (SQLite): INSERT INTO "Permission" (Description, Id) VALUES (@p0, @p1);@p0 = 'p1', @p1 = 1 INSERT INTO "User" (Email) VALUES (@p0); select last_insert_rowid();@p0 = '[email protected]' SELECT user0_.Id as Id2_0_, user0_.Email as Email2_0_ FROM "User" user0_ WHERE user0_.Id=@p0;@p0 = 1 SELECT permission0_.UserId as UserId1_, permission0_.PermissionId as Permissi2_1_, permission1_.Id as Id4_0_, permission1_.Description as Descript2_4_0_ FROM User_Permissions permission0_ left outer join "Permission" permission1_ on permission0_.PermissionId=permission1_.Id WHERE permission0_.UserId=@p0;@p0 = 1 We can clearly see that there is no record inserted into the User_Permissions table where it should be. Not sure what I am doing wrong and need an advice. So can you please help me to pass this test. Thanks, Dmitriy.

  Read the article

• Authoritative sources about Database vs. Flatfile decision

  - by FastAl

  <tldr>looking for a reference to a book or other undeniably authoritative source that gives reasons when you should choose a database vs. when you should choose other storage methods. I have provided an un-authoritative list of reasons about 2/3 of the way down this post.</tldr> I have a situation at my company where a database is being used where it would be better to use another solution (in this case, an auto-generated piece of source code that contains a static lookup table, searched by binary sort). Normally, a database would be an OK solution even though the problem does not require a database, e.g, none of the elements of ACID are needed, as it is read-only data, updated about every 3-5 years (also requiring other sourcecode changes), and fits in memory, and can be keyed into via binary search (a tad faster than db, but speed is not an issue). The problem is that this code runs on our enterprise server, but is shared with several PC platforms (some disconnected, some use a central DB, etc.), and parts of it are managed by multiple programming units, parts by the DBAs, parts even by mathematicians in another department, etc. These hit their own platform’s version of their databases (containing their own copy of the static data). What happens is that every implementation, every little change, something different goes wrong. There are many other issues as well. I can’t even use a flatfile, because one mode of running on our enterprise server does not have permission to read files (only databases, and of course, its own literal storage, e.g., in-source table). Of course, other parts of the system use databases in proper, less obscure manners; there is no problem with those parts. So why don’t we just change it? I don’t have administrative ability to force a change. But I’m affected because sometimes I have to help fix the problems, but mostly because it causes outages and tons of extra IT time by other programmers and d*mmit that makes me mad! The reason neither management, nor the designers of the system, can see the problem is that they propose a solution that won’t work: increase communication; implement more safeguards and standards; etc. But every time, in a different part of the already-pared-down but still multi-step processes, a few different diligent, hard-working, top performing IT personnel make a unique subtle error that causes it to fail, sometimes after the last round of testing! And in general these are not single-person failures, but understandable miscommunications. And communication at our company is actually better than most. People just don't think that's the case because they haven't dug into the matter. However, I have it on very good word from somebody with extensive formal study of sociology and psychology that the relatively small amount of less-than-proper database usage in this gigantic cross-platform multi-source, multi-language project is bureaucratically un-maintainable. Impossible. No chance. At least with Human Beings in the loop, and it can’t be automated. In addition, the management and developers who could change this, though intelligent and capable, don’t understand the rigidity of this ‘how humans are’ issue, and are not convincible on the matter. The reason putting the static data in sourcecode will solve the problem is, although the solution is less sexy than a database, it would function with no technical drawbacks; and since the sharing of sourcecode already works very well, you basically erase any database-related effort from this section of the project, along with all the drawbacks of it that are causing problems. OK, that’s the background, for the curious. I won’t be able to convince management that this is an unfixable sociological problem, and that the real solution is coding around these limits of human nature, just as you would code around a bug in a 3rd party component that you can’t change. So what I have to do is exploit the unsuitableness of the database solution, and not do it using logic, but rather authority. I am aware of many reasons, and posts on this site giving reasons for one over the other; I’m not looking for lists of reasons like these (although you can add a comment if I've miss a doozy): WHY USE A DATABASE? instead of flatfile/other DB vs. file: if you need... Random Read / Transparent search optimization Advanced / varied / customizable Searching and sorting capabilities Transaction/rollback Locks, semaphores Concurrency control / Shared users Security 1-many/m-m is easier Easy modification Scalability Load Balancing Random updates / inserts / deletes Advanced query Administrative control of design, etc. SQL / learning curve Debugging / Logging Centralized / Live Backup capabilities Cached queries / dvlp & cache execution plans Interleaved update/read Referential integrity, avoid redundant/missing/corrupt/out-of-sync data Reporting (from on olap or oltp db) / turnkey generation tools [Disadvantages:] Important to get right the first time - professional design - but only b/c it's meant to last s/w & h/w cost Usu. over a network, speed issue (best vs. best design vs. local=even then a separate process req's marshalling/netwk layers/inter-p comm) indicies and query processing can stand in the way of simple processing (vs. flatfile) WHY USE FLATFILE: If you only need... Sequential Row processing only Limited usage append only (no reading, no master key/update) Only Update the record you're reading (fixed length recs only) Too big to fit into memory If Local disk / read-ahead network connection Portability / small system Email / cut & Paste / store as document by novice - simple format Low design learning curve but high cost later WHY USE IN-MEMORY/TABLE (tables, arrays, etc.): if you need... Processing a single db/ff record that was imported Known size of data Static data if hardcoding the table Narrow, unchanging use (e.g., one program or proc) -includes a class that will be shared, but encapsulates its data manipulation Extreme speed needed / high transaction frequency Random access - but search is dependent on implementation Following are some other posts about the topic: http://stackoverflow.com/questions/1499239/database-vs-flat-text-file-what-are-some-technical-reasons-for-choosing-one-over http://stackoverflow.com/questions/332825/are-flat-file-databases-any-good http://stackoverflow.com/questions/2356851/database-vs-flat-files http://stackoverflow.com/questions/514455/databases-vs-plain-text/514530 What I’d like to know is if anybody could recommend a hard, authoritative source containing these reasons. I’m looking for a paper book I can buy, or a reputable website with whitepapers about the issue (e.g., Microsoft, IBM), not counting the user-generated content on those sites. This will have a greater change to elicit a change that I’m looking for: less wasted programmer time, and more reliable programs. Thanks very much for your help. You win a prize for reading such a large post!

  Read the article

• how to make the android app load faster?

  - by Tapan Desai

  I have designed an application for android, in which i am showing a splash screen before the main activity is started but the application takes 5-7 seconds to start on low-end devices. I want to reduce that time to as low as possible. I have been trying to reduce the things to be done in onCreate() but now i cannot remove any thing more from that. I am pasting the code that i have used to show the splash and the code from MainActivity. Please help me in reducing the startup time of the application. Splash.java @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_splash); txtLoad = (TextView) findViewById(R.id.txtLoading); txtLoad.setText("v1.0"); new Thread() { public void run() { try { sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } finally { finish(); Intent intent = new Intent(SplashActivity.this,MainActivity.class); startActivity(intent); } } }.start(); } MainActivity.java @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_main); editType1UserName = (EditText) findViewById(R.id.editTextType1UserName); editType1Password = (EditText) findViewById(R.id.editTextType1Password); editType2UserName = (EditText) findViewById(R.id.editTextType2UserName); editType2Password = (EditText) findViewById(R.id.editTextType2Password); editType3UserName = (EditText) findViewById(R.id.editTextType3UserName); editType3Password = (EditText) findViewById(R.id.editTextType3Password); editType4UserName = (EditText) findViewById(R.id.editTextType4UserName); editType4Password = (EditText) findViewById(R.id.editTextType4Password); mTxtPhoneNo = (AutoCompleteTextView) findViewById(R.id.mmWhoNo); mTxtPhoneNo.setThreshold(1); editText = (EditText) findViewById(R.id.editTextMessage); spinner1 = (Spinner) findViewById(R.id.spinnerGateway); btnsend = (Button) findViewById(R.id.btnSend); btnContact = (Button) findViewById(R.id.btnContact); btnsend.setOnClickListener((OnClickListener) this); btnContact.setOnClickListener((OnClickListener) this); mPeopleList = new ArrayList<Map<String, String>>(); PopulatePeopleList(); mAdapter = new SimpleAdapter(this, mPeopleList, R.layout.custcontview, new String[] { "Name", "Phone", "Type" }, new int[] { R.id.ccontName, R.id.ccontNo, R.id.ccontType }); mTxtPhoneNo.setAdapter(mAdapter); mTxtPhoneNo.setOnItemClickListener((OnItemClickListener) this); readPerson(); Panel panel; topPanel = panel = (Panel) findViewById(R.id.mytopPanel); panel.setOnPanelListener((OnPanelListener) this); panel.setInterpolator(new BounceInterpolator(Type.OUT)); getLoginDetails(); }

  Read the article

• I've got my 2D/3D conversion working perfectly, how to do perspective

  - by user346992

  Although the context of this question is about making a 2d/3d game, the problem i have boils down to some math. Although its a 2.5D world, lets pretend its just 2d for this question. // xa: x-accent, the x coordinate of the projection // mapP: a coordinate on a map which need to be projected // _Dist_ values are constants for the projection, choosing them correctly will result in i.e. an isometric projection xa = mapP.x * xDistX + mapP.y * xDistY; ya = mapP.x * yDistX + mapP.y * yDistY; xDistX and yDistX determine the angle of the x-axis, and xDistY and yDistY determine the angle of the y-axis on the projection (and also the size of the grid, but lets assume this is 1-pixel for simplicity). x-axis-angle = atan(yDistX/xDistX) y-axis-angle = atan(yDistY/yDistY) a "normal" coordinate system like this --------------- x | | | | | y has values like this: xDistX = 1; yDistX = 0; xDistY = 0; YDistY = 1; So every step in x direction will result on the projection to 1 pixel to the right end 0 pixels down. Every step in the y direction of the projection will result in 0 steps to the right and 1 pixel down. When choosing the correct xDistX, yDistX, xDistY, yDistY, you can project any trimetric or dimetric system (which is why i chose this). So far so good, when this is drawn everything turns out okay. If "my system" and mindset are clear, lets move on to perspective. I wanted to add some perspective to this grid so i added some extra's like this: camera = new MapPoint(60, 60); dx = mapP.x - camera.x; // delta x dy = mapP.y - camera.y; // delta y dist = Math.sqrt(dx * dx + dy * dy); // dist is the distance to the camera, Pythagoras etc.. all objects must be in front of the camera fac = 1 - dist / 100; // this formula determines the amount of perspective xa = fac * (mapP.x * xDistX + mapP.y * xDistY) ; ya = fac * (mapP.x * yDistX + mapP.y * yDistY ); Now the real hard part... what if you got a (xa,ya) point on the projection and want to calculate the original point (x,y). For the first case (without perspective) i did find the inverse function, but how can this be done for the formula with the perspective. May math skills are not quite up to the challenge to solve this. ( I vaguely remember from a long time ago mathematica could create inverse function for some special cases... could it solve this problem? Could someone maybe try?)

  Read the article

• c#: Clean way to fit a collection into a multidimensional array?

  - by Rosarch

  I have an ICollection<MapNode>. Each MapNode has a Position attribute, which is a Point. I want to sort these points first by Y value, then by X value, and put them in a multidimensional array (MapNode[,]). The collection would look something like this: (30, 20) (20, 20) (20, 30) (30, 10) (30, 30) (20, 10) And the final product: (20, 10) (20, 20) (20, 30) (30, 10) (30, 20) (30, 30) Here is the code I have come up with to do it. Is this hideously unreadable? I feel like it's more hacky than it needs to be. private Map createWorldPathNodes() { ICollection<MapNode> points = new HashSet<MapNode>(); Rectangle worldBounds = WorldQueryUtils.WorldBounds(); for (float x = worldBounds.Left; x < worldBounds.Right; x += PATH_NODE_CHUNK_SIZE) { for (float y = worldBounds.Y; y > worldBounds.Height; y -= PATH_NODE_CHUNK_SIZE) { // default is that everywhere is navigable; // a different function is responsible for determining the real value points.Add(new MapNode(true, new Point((int)x, (int)y))); } } int distinctXValues = points.Select(node => node.Position.X).Distinct().Count(); int distinctYValues = points.Select(node => node.Position.Y).Distinct().Count(); IList<MapNode[]> mapNodeRowsToAdd = new List<MapNode[]>(); while (points.Count > 0) // every iteration will take a row out of points { // get all the nodes with the greatest Y value currently in the collection int currentMaxY = points.Select(node => node.Position.Y).Max(); ICollection<MapNode> ythRow = points.Where(node => node.Position.Y == currentMaxY).ToList(); // remove these nodes from the pool we're picking from points = points.Where(node => ! ythRow.Contains(node)).ToList(); // ToList() is just so it is still a collection // put the nodes with max y value in the array, sorting by X value mapNodeRowsToAdd.Add(ythRow.OrderByDescending(node => node.Position.X).ToArray()); } MapNode[,] mapNodes = new MapNode[distinctXValues, distinctYValues]; int xValuesAdded = 0; int yValuesAdded = 0; foreach (MapNode[] mapNodeRow in mapNodeRowsToAdd) { xValuesAdded = 0; foreach (MapNode node in mapNodeRow) { // [y, x] may seem backwards, but mapNodes[y] == the yth row mapNodes[yValuesAdded, xValuesAdded] = node; xValuesAdded++; } yValuesAdded++; } return pathNodes; } The above function seems to work pretty well, but it hasn't been subjected to bulletproof testing yet.

  Read the article

• Help me please, javascript place problem or another thing??

  - by ilkdrl

  <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Urunler.aspx.cs" Inherits="Urunler" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <meta http-equiv="content-language" content="en" /> <link href="rss/example_ticker.css" rel="stylesheet" type="text/css" /> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script> <script src="rss/jquery.zrssfeed.min.js" type="text/javascript"></script> <script src="rss/jquery.vticker.js" type="text/javascript"></script> <title></title> <script type="text/javascript" src="lightbox/js/prototype.js"></script> <script type="text/javascript" src="lightbox/js/scriptaculous.js?load=effects,builder"></script> <script type="text/javascript" src="lightbox/js/lightbox.js"></script> <link rel="stylesheet" href="lightbox/css/lightbox.css" type="text/css" media="screen" /> <style type="text/css"> ........... ........... ........... <td style="background-color: #808080"> <script type="text/javascript"> $(document).ready(function () { $('#ticker1').rssfeed('http://www.xxxxxxx.com/map.asp').ajaxStop(function () { $('#ticker1 div.rssBody').vTicker({ showItems: 3 }); }); }); </script> <div id="ticker1" > </div> Hi, i have two scripts.lightbox and rss. lightbox script works very well in mywebform1 but rss feed dont work.I didnot solve that?Help me please. PS: on the other hand, my another webpage(mywebform2) in same website has only rss feed and works very well.

  Read the article

• how to debug "deep" crashes in Android?

  - by eerok512

  Hi All, I've been trying to debug an android crash that is occurring without a Java Stack Trace... Java Stack Trace bugs are very easy for me to fix... but this bug I'm getting seems to be crashing inside the "NDK" or whatever it is the deep internals of Android are called... I've made no modifications to the NDK btw... I just dunno what else to call that layer hehe. Anyway I'm mainly looking for advice on deep-debug methods, rather than help with this specific problem... because I doubt I can post all the source code involved... so really I just need to know how to set breakpoints at the deep layers or whatever other methods there are to trace deep-crashes to their source... so I will briefly describe the bug and then post a LogCat. I have an app with 7 Activities Activity_INTRO Activity_EULA Activity_MAIN Activity_Contact Activity_News Activity_Library Activity_More INTRO is the initiating one... it fades in some company logos... after displaying them for a set time it jumps to the EULA activity... after the user accepts the EULA, it jumps to MAIN... MAIN then creates a TabHost and populates it with the 4 remaining activities now heres the thing... when I click on say, the More tab of the TabHost, the app pauses for a few seconds and then hard-crashes... no java stack trace, but an actual ASM level trace with the registers and IP and stack... the same thing occurs no matter which tab I select, Contact, News, Library, More... all of them crash with the same hard-crash if however I set the manifest to start the app at Activity_MAIN, bypassing the INTRO and EULA, then these crashes do not occur... so something is lingering from those opening activities that is somehow hosing the TabHost'ed Activities... and I'm wondering what the hell that could be... because I'm using finish() on those activites when they need to jump... in fact here is how I'm doing it let me know if you see any bugs: when jumping from INTRO to EULA I do: //Display the EULA Intent newIntent = new Intent (avi, Activity_EULA.class); startActivity (newIntent); finish(); and EULA to MAIN: Intent newIntent = new Intent (this, Activity_Main.class); startActivity (newIntent); finish(); anyway, here is the hard crash log... please let me know if there is some way I can reverse engineer either /system/lib/libcutils.so or /system/lib/libandroid_runtime.so, because I think the crash is happening in one of them... i think its happening in the libandroid_runtime in fact.... anyway on to the log: 12-25 00:56:07.322: INFO/DEBUG(551): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** 12-25 00:56:07.332: INFO/DEBUG(551): Build fingerprint: 'generic/sdk/generic/:1.5/CUPCAKE/150240:eng/test-keys' 12-25 00:56:07.362: INFO/DEBUG(551): pid: 722, tid: 723 >>> com.killerapps.chokes <<< 12-25 00:56:07.362: INFO/DEBUG(551): signal 11 (SIGSEGV), fault addr 00000004 12-25 00:56:07.362: INFO/DEBUG(551): r0 00000004 r1 40021800 r2 00000004 r3 ad3296c5 12-25 00:56:07.372: INFO/DEBUG(551): r4 00000000 r5 00000000 r6 ad342da5 r7 41039fb8 12-25 00:56:07.372: INFO/DEBUG(551): r8 100ffcb0 r9 41039fb0 10 41e014a0 fp 00001071 12-25 00:56:07.382: INFO/DEBUG(551): ip ad35b874 sp 100ffc98 lr ad3296cf pc afb045a8 cpsr 00000010 12-25 00:56:07.552: INFO/DEBUG(551): #00 pc 000045a8 /system/lib/libcutils.so 12-25 00:56:07.572: INFO/DEBUG(551): #01 lr ad3296cf /system/lib/libandroid_runtime.so 12-25 00:56:07.582: INFO/DEBUG(551): stack: 12-25 00:56:07.582: INFO/DEBUG(551): 100ffc58 00000000 12-25 00:56:07.592: INFO/DEBUG(551): 100ffc5c 001c5278 [heap] 12-25 00:56:07.602: INFO/DEBUG(551): 100ffc60 000000da 12-25 00:56:07.602: INFO/DEBUG(551): 100ffc64 0016c778 [heap] 12-25 00:56:07.602: INFO/DEBUG(551): 100ffc68 100ffcc8 12-25 00:56:07.602: INFO/DEBUG(551): 100ffc6c 001c5278 [heap] 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc70 427d1ac0 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc74 000000c1 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc78 40021800 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc7c 000000c2 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc80 00000000 12-25 00:56:07.612: INFO/DEBUG(551): 100ffc84 00000000 12-25 00:56:07.622: INFO/DEBUG(551): 100ffc88 00000000 12-25 00:56:07.622: INFO/DEBUG(551): 100ffc8c 00000000 12-25 00:56:07.622: INFO/DEBUG(551): 100ffc90 df002777 12-25 00:56:07.632: INFO/DEBUG(551): 100ffc94 e3a070ad 12-25 00:56:07.632: INFO/DEBUG(551): #00 100ffc98 00000000 12-25 00:56:07.632: INFO/DEBUG(551): 100ffc9c ad3296cf /system/lib/libandroid_runtime.so 12-25 00:56:07.632: INFO/DEBUG(551): 100ffca0 100ffcd0 12-25 00:56:07.642: INFO/DEBUG(551): 100ffca4 ad342db5 /system/lib/libandroid_runtime.so 12-25 00:56:07.642: INFO/DEBUG(551): 100ffca8 410a79d0 12-25 00:56:07.642: INFO/DEBUG(551): 100ffcac ad00e3b8 /system/lib/libdvm.so 12-25 00:56:07.652: INFO/DEBUG(551): 100ffcb0 410a79d0 12-25 00:56:07.652: INFO/DEBUG(551): 100ffcb4 0016bac0 [heap] 12-25 00:56:07.662: INFO/DEBUG(551): 100ffcb8 ad342da5 /system/lib/libandroid_runtime.so 12-25 00:56:07.662: INFO/DEBUG(551): 100ffcbc 40021800 12-25 00:56:07.662: INFO/DEBUG(551): 100ffcc0 410a79d0 12-25 00:56:07.662: INFO/DEBUG(551): 100ffcc4 afe39dd0 12-25 00:56:07.662: INFO/DEBUG(551): 100ffcc8 100ffcd0 12-25 00:56:07.662: INFO/DEBUG(551): 100ffccc ad040a8d /system/lib/libdvm.so 12-25 00:56:07.672: INFO/DEBUG(551): 100ffcd0 41039fb0 12-25 00:56:07.672: INFO/DEBUG(551): 100ffcd4 420000f8 12-25 00:56:07.672: INFO/DEBUG(551): 100ffcd8 ad342da5 /system/lib/libandroid_runtime.so 12-25 00:56:07.672: INFO/DEBUG(551): 100ffcdc 100ffd48 12-25 00:56:07.852: DEBUG/dalvikvm(722): GC freed 367 objects / 15144 bytes in 210ms 12-25 00:56:08.081: DEBUG/InetAddress(722): www.akillerapp.com: 74.86.47.202 (family 2, proto 6) 12-25 00:56:08.242: DEBUG/dalvikvm(722): GC freed 62 objects / 2328 bytes in 122ms 12-25 00:56:08.771: DEBUG/dalvikvm(722): GC freed 245 objects / 11744 bytes in 179ms 12-25 00:56:09.131: INFO/ActivityManager(577): Process com.killerapps.chokes (pid 722) has died. 12-25 00:56:09.171: INFO/WindowManager(577): WIN DEATH: Window{43719320 com.killerapps.chokes/com.killerapps.chokes.Activity_Main paused=false} 12-25 00:56:09.251: INFO/DEBUG(551): debuggerd committing suicide to free the zombie! 12-25 00:56:09.291: DEBUG/Zygote(553): Process 722 terminated by signal (11) 12-25 00:56:09.311: INFO/DEBUG(781): debuggerd: Jun 30 2009 17:00:51 12-25 00:56:09.331: WARN/InputManagerService(577): Got RemoteException sending setActive(false) notification to pid 722 uid 10020

  Read the article

• Problem accessing updated variables within OnTouch

  - by Jay Smith

  I have an OnTouch and a setOnTouchListener that updates varibles which contain screen coord info. The problem is it doesnt seem to ever update them. On line 78, RGB.setText(test); it never changes from 0.0. If i were to move that line and the line above it into the onTouch it updates. any idea what is wrong? Thank you. package com.evankimia.huskybus; import com.test.huskybus.R; import android.app.Activity; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; import android.widget.TextView; public class HuskyBus extends Activity { TextView RGB; private CampusMap mCampusMap; private float startX = 0; //track x from one ACTION_MOVE to the next private float startY = 0; //track y from one ACTION_MOVE to the next float scrollByX = 0; //x amount to scroll by float scrollByY = 0; //y amount to scroll by /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); RGB = (TextView) findViewById(R.id.coordBox); mCampusMap = (CampusMap) findViewById(R.id.map); mCampusMap.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { // TODO Auto-generated method stub switch (event.getAction()) { case MotionEvent.ACTION_DOWN: // Remember our initial down event location. startX = event.getRawX(); startY = event.getRawY(); break; case MotionEvent.ACTION_MOVE: float x = event.getRawX(); float y = event.getRawY(); // Calculate move update. This will happen many times // during the course of a single movement gesture. scrollByX = x - startX; //move update x increment scrollByY = y - startY; //move update y increment startX = x; //reset initial values to latest startY = y; mCampusMap.invalidate(); break; }//end switch return false; } ; }); //end onDraw? String test = "" + scrollByX; RGB.setText(test); } }

  Read the article

• Is this scatter-brained workflow realizable in Git?

  - by Luke Maurer

  This is what I'd like my workflow to look like at a conceptual level: I hack on my new feature for a while I notice a typo in a comment I change it Since the typo is completely unrelated to anything else, I put that change in a pile of comment fixes I keep working on the code I realize I need to flesh out a few utility functions I do so I put that change in its own pile Steps 2, 3, and 4 each repeat throughout the day I finish the new feature and put the changes for that feature in a pile I push nice patches upstream: One with the new feature, a few for the other tweaks, and one with a bunch of comment fixes if enough have accumulated Since I'm both lazy and a perfectionist, I want to be able to do some things out of order: I might correct a typo but forget to put it in the comment fix pile; when I prepare the upstream patches (I'm using git-svn, so I need to be pretty deliberate about these), I'll then pull out the comment fixes at that point. I might forget to separate things altogether until the very end. But I might /also/ have committed some of the piles along the way (sorry, the metaphor is breaking down …). This is all rather like just using Eclipse changesets with SVN, only I can have different changes to the same file in different piles (having to disentangle changes into different commits is what motivated me to move to git-svn, in fact …), and with Git I can have my full discombobulated change history, experimental branches and all, but still make a nice, neat patch. I've just recently started with Git after having wanted to for a good while, and I'm quite happy so far. The biggest way in which the above workflow doesn't really map into Git, though, is that a “bin” can't really be just a local branch, since the working tree only ever reflects the state of a single branch. Or maybe the Git index is a “pile,” and what I want is to have more than one somehow (effectively). I can think of a few ways to approximate what I want (maybe creative use of stash? Intricate stash-checkout-merge dances?), but my grasp on Git isn't solid enough to be sure of how best to put all the pieces together. It's said that Git is more a toolkit than a VCS, so I guess the question comes down to: How do I build this thing with these tools?

  Read the article

• Dealing with external processes

  - by Jesse Aldridge

  I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

  Read the article

< Previous Page | 314 315 316 317 318 319 320 321 322 323 324 325  | Next Page >