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• Is Domain Anaemia appropriate in a Service Oriented Architecture?

  - by Stimul8d

  I want to be clear on this. When I say domain anaemia, I mean intentional domain anaemia, not accidental. In a world where most of our business logic is hidden away behind a bunch of services, is a full domain model really necessary? This is the question I've had to ask myself recently since working on a project where the "domain" model is in reality a persistence model; none of the domain objects contain any methods and this is a very intentional decision. Initially, I shuddered when I saw a library full of what are essentially type-safe data containers but after some thought it struck me that this particular system doesn't do much but basic CRUD operations, so maybe in this case this is a good choice. My problem I guess is that my experience so far has been very much focussed on a rich domain model so it threw me a little. The remainder of the domain logic is hidden away in a group of helpers, facades and factories which live in a separate assembly. I'm keen to hear what people's thoughts are on this. Obviously, the considerations for reuse of these classes are much simpler but is really that great a benefit?

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• Working with Java using methods and arrays [closed]

  - by jordan

  Hi i'm a newb at java and for one of my labs I have to create a instant messenger client with these requirements: add buddyList instance variable add IMClient constructor to create ArrayList addBuddy method removeBuddy method findBuddy method printBuddyList method what's the best way to go about this? so far I have this: public class IMClient { private String userId; // User id private String password; // Password private int status; // Status code for user: 1 - Online, 2 - Off-line, 3 - Away public IMClient(String userId, String password, int status) { super(); this.userId = userId; this.password = password; this.status = status; } // Returns true if password as a parameter matches password instance variable. public boolean checkPassword(String password) { return this.password.equals(password); } public String toString() { StringBuffer buf = new StringBuffer(100); buf.append(" User id: "); buf.append(userId); buf.append(" Password: "); buf.append(password); buf.append(" Status: "); buf.append(status); return buf.toString(); } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public int getStatus() { return status; } public void setStatus(int status) { this.status = status; } public static void main(String[] args) { } }

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• Flex/Flash: Don't show 'bar' cursor when dragging over a TextField/TextArea?

  - by David Wolever

  As the title suggests, how can I prevent the "bar" cursor from appearing when I click-and-drag over a TextField? For example, consider this interaction: I'd like to prevent the cursor changing to the "bar" in step "2". How can I do that? I've tried fiddling with the selectable flag: protected static function fixMouseOverAfordance(field:TextField):void { var iOwnClick:Boolean = false; function handleMouseOver(event:MouseEvent):void { if (event.buttonDown) { field.selectable = iOwnClick; } else { field.selectable = true; iOwnClick = false; } } field.addEventListener(MouseEvent.MOUSE_OVER, handleMouseOver, false, EventPriority.CURSOR_MANAGEMENT+1); field.addEventListener(MouseEvent.ROLL_OVER, handleMouseOver, false, EventPriority.CURSOR_MANAGEMENT+1); field.addEventListener(MouseEvent.MOUSE_MOVE, handleMouseOver, false, EventPriority.CURSOR_MANAGEMENT+1); field.addEventListener(MouseEvent.MOUSE_DOWN, function(event:MouseEvent):void { iOwnClick = true; field.selectable = true; }); } But the "bar" cursor still appears the first time the mouse is moved over the text field (however, after it has been moved out then moved back in, it does the right thing).

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• Invalid Pointer Operation, advice requested with debugging

  - by Xanyx

  I appear to have created code that is trashing memory. Having never had such problems before, i am now settign an Invalid Pointer Operation. In the following the value of the const string sFilename gets trashed after my call to PromptForXYZPropertiesSettings. // Allow the user to quickly display the properties of XYZ without needing to display the full Editor function PromptForXYZProperties(const sFilename:string; var AXYZProperties: TXYZProperties): boolean; var PropEditor: TdlgEditor; begin PropEditor:= TdlgEditor.create(nil); try PropEditor.LoadFromFile(sFilename); Other Details: Delphi 2007, Windows 7 64 bit, but can reproduce when testing EXE on XP REMOVING CONST STOPS PROBLEM FROM EXHIBITING (but presumably the problem is thus just lurking) PropEditor.PromptForXYZPropertiesSettings creates and shows a form. If I disable the ShowModal call then the memory is not trashed. Even though i have REMOVED ALL CONTROLS AND CODE from the form So I would like some advice on how to debug the issue. I was thinking perhaps watching the memory pointer where the sFilename var exists to see where it gets trashed, but not sure how i would do that (obviously needs to be done within the app so is owned memory). Thanks

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• PHP variable equals true no matter what the value, even 0

  - by kaigoh

  This is the var_dump: object(stdClass)#27 (8) { ["SETTING_ID"]=> string(2) "25" ["SETTING_SOURCE"]=> string(2) "XV" ["SETTING_FLEET"]=> string(3) "313" ["SETTING_EXAM"]=> string(1) "A" ["SETTING_HIDE"]=> string(1) "0" ["SETTING_THRESHOLD"]=> string(1) "0" ["SETTING_COUNT"]=> string(8) "POSITIVE" ["SETTING_USAGE"]=> string(7) "MILEAGE" } The variable I am testing is SETTING_HIDE. This is being pulled from MySQL using the Code igniter framework. I don't know if it is just me being thick after a rather long day at work or what, but no matter what value the variable holds, any if statement made against it returns true, even when typecast as a boolean or a direct string comparison, ie. == "0" or == "1". Anyone with a fresh pair of eyes care to make me feel silly!?! :) Just to clarify: Have tried the following: if($examSetting->SETTING_HIDE == "1") { $showOnABC = "checked=\"checked\""; } if((bool)$examSetting->SETTING_HIDE) { $showOnABC = "checked=\"checked\""; } if($examSetting->SETTING_COUNT == "POSITIVE") further on in my code works perfectly.

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• Session variable gets updated automatically

  - by user1869914

  protected void btningAccept_Click(object sender, EventArgs e) { if(!(txtLOVCode.Text==" "||txtLOVvalue.Text==" ")) { rowid++; // DFDLOVlst.Visible=true; DataTable dt = createTemptable(); dt = (DataTable)Session["dfdtemptable"]; DataRow dr = dt.NewRow(); dr["prociLOV_Id"] = rowid; dr["prociLOV_Value"] = txtLOVvalue.Text; dr["prociLOV_Code"] = txtLOVCode.Text; Boolean isalreadyinLOVlst = false; foreach (DataRow chkrow in dt.Rows) { if (String.Equals(dr["prociLOV_Value"].ToString().Trim(), chkrow["prociLOV_Value"].ToString().Trim(),StringComparison.CurrentCultureIgnoreCase) && String.Equals(dr["prociLOV_Code"].ToString().Trim(), chkrow["prociLOV_Code"].ToString().Trim(), StringComparison.CurrentCultureIgnoreCase)) { isalreadyinLOVlst = true; break; } } if (isalreadyinLOVlst) { this.lblMessage.Text = "LOV value: " + dr["prociLOV_Value"].ToString() + ": " + dr["prociLOV_Code"].ToString() + " already exits"; } else { this.lblMessage.Text = " "; dt.Rows.Add(dr); DataTable addedLOV = createTemptable(); addedLOV = (DataTable)Session["addedLOV"]; addedLOV.ImportRow(dr); ; Session["addedLOV"] = addedLOV; } DFDLOVlst.DataSource = dt; DFDLOVlst.DataBind(); // dt.AcceptChanges(); Session["dfdtemptable"] = dt; txtLOVCode.Text = ""; txtLOVvalue.Text = ""; MDIngrdientsCode.Hide(); this.txtLOVvalue.ReadOnly = false; this.txtLOVCode.ReadOnly = false; } else this.lblMessage.Text="NO LOV VALUES ENTERED"; } Here the session varible Session["dfdtemptable"] and Session["addedLOV"] both gets updated twice and their row count becomes 2 for each session varible..But the row count sholud be 1 for each session varible.But the Session variable gets updated on the other Session varibles updation.. The Session["dfdtemptable"] gets updated when Session["addedLOV"] is assigned or updated..Can't figure out the problem..?

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• Interesting Scala typing solution, doesn't work in 2.7.7?

  - by djc

  I'm trying to build some image algebra code that can work with images (basically a linear pixel buffer + dimensions) that have different types for the pixel. To get this to work, I've defined a parametrized Pixel trait with a few methods that should be able to get used with any Pixel subclass. (For now, I'm only interested in operations that work on the same Pixel type.) Here it is: trait Pixel[T <: Pixel[T]] { def mul(v: Double): T def max(v: T): T def div(v: Double): T def div(v: T): T } Now I define a single Pixel type that has storage based on three doubles (basically RGB 0.0-1.0), I've called it TripleDoublePixel: class TripleDoublePixel(v: Array[Double]) extends Pixel[TripleDoublePixel] { var data: Array[Double] = v def this() = this(Array(0.0, 0.0, 0.0)) def toString(): String = { "(" + data(0) + ", " + data(1) + ", " + data(2) + ")" } def increment(v: TripleDoublePixel) { data(0) += v.data(0) data(1) += v.data(1) data(2) += v.data(2) } def mul(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x * v)) } def div(v: Double): TripleDoublePixel = { new TripleDoublePixel(data.map(x => x / v)) } def div(v: TripleDoublePixel): TripleDoublePixel = { var tmp = new Array[Double](3) tmp(0) = data(0) / v.data(0) tmp(1) = data(1) / v.data(1) tmp(2) = data(2) / v.data(2) new TripleDoublePixel(tmp) } def max(v: TripleDoublePixel): TripleDoublePixel = { val lv = data(0) * data(0) + data(1) * data(1) + data(2) * data(2) val vv = v.data(0) * v.data(0) + v.data(1) * v.data(1) + v.data(2) * v.data(2) if (lv > vv) (this) else v } } Now I want to write code to use this, that doesn't have to know what type the pixels are. For example: def idiv[T](a: Image[T], b: Image[T]) { for (i <- 0 until a.data.size) { a.data(i) = a.data(i).div(b.data(i)) } } Unfortunately, this doesn't compile: (fragment of lindet-gen.scala):145: error: value div is not a member of T a.data(i) = a.data(i).div(b.data(i)) I was told in #scala that this worked for someone else, but that was on 2.8. I've tried to get 2.8-rc1 going, but it doesn't compile for me. Is there any way to get this to work in 2.7.7?

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• MSI File/Registry failures on Windows Server 2008/Windows 7 (x64)

  - by Luca

  I'm trying to deploy an application on Windows Server 2008 (SP2 x64) and Windows 7 (x64), using VS2005 Installer Project. The MSI version (I think) it the 2.0. Everything works fine, except that some registry keys and some files are not copied on the install machine. The MSI system doesn't notify about nothing (and I don't know whether MSI logs its operations). Are there incompatibilities between my MSI installer project and these new OSes? It seems to me that the OS protect itself for being modified in some part. For example, I'm trying to set the registry keys: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\WinLogon\SpecialAccounts\UserList\User but it is not created. In the same installer there are many other keys, which are created like expected (as they always did before on Windows XP and Windows Server 2003). To provide another example, I'm trying to install the file %SystemFolder%\oobe\info\backgrounds\backgroundDefault.jpg (where %SystemFolder% is typically "C:\Windows\System32"), but the file is not copied at all!!! What's going on? I've found the backgroundDefault.jpg file is located in another directory: %SystemRoot%\SysWOW64\oobe\info. But I've not specified nothing about a System (64 bit) folder. How can I copy the file in the right place?

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• REST design: what verb and resource name to use for a filtering service

  - by kabaros

  I am developing a cleanup/filtering service that has a method that receives a list of objects serialized in xml, and apply some filtering rules to return a subset of those objects. In a REST-ful service, what verb shall I use for such a method? I thought that GET is a natural choice, but I have to put the serialized XML in the body of the request which works but feels incorrect. The other verbs don't seem to fit semantically. What is a good way to define that Service interface? Naming the resource /Cleanup or /Filter seems weird mainly because in the examples I see online, it is always a name rather than a verb being used for resource name. Am I right to feel that REST services are better suited for CRUD operations and you start bending the rules in situations like this service? If yes, am I then making a wrong architectural choice. I've pushed to develop this service in REST-ful style (as opposed to SOAP) for simplicity, but such awkward cases happen a lot and make me feel like I am missing something. Either choosing REST where it shouldn't be used or may be over-thinking some stuff that doesn't really matter? In that case, what really matters?

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• steam condenser java errors

  - by w0rm

  I've been working on a little project involving Steam Condenser, a Steam API written in Java, but I haven't been able to actually do anything with it. I'll explain. This is what the wiki tells me: SteamId id = new SteamId("demomenz"); GameStats stats = id.getGameStats("tf2"); List achievements = stats.getAchievements(); The problem is, eclipse doesn't like it apparently, as it spits out this error: The constructor SteamId(String) is undefined and it gives me the option to change it to: SteamId id = new SteamId("demomenz", false); But at this point a different error comes out: The constructor SteamId(Object, boolean) is not visible So, I'm assuming this function is internal to the API, and should not be called from the outside. If anyone is familiar with this, or has a clue on why I'm getting this error (I'm fairly new to Java development), an answer would be greatly appreciated. UPDATE: The constructor SteamId(String) is undefined This is if I use SteamId.create(ConvertedID); (ConvertedID is a String containing the Steam64 ID). At this point I believe this API is not that well written, at least for java. Any other idea?

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• How to implement iterator as an attribute of a class in Java

  - by de3

  Hi, let's say I have this simple MyArray class, with two simple methods: add, delete and an iterator. In the main method we can see how it is supposed to be used: public class MyArray { int start; int end; int[] arr; myIterator it; public MyArray(){ this.start=0; this.end=0; this.arr=new int[500]; it=new myIterator(); } public void add(int el){ this.arr[this.end]=el; this.end++; } public void delete(){ this.arr[this.start]=0; this.start++; } public static void main(String[] args){ MyArray m=new MyArray(); m.add(3); m.add(299); m.add(19); m.add(27); while(m.it.hasNext()){ System.out.println(m.it.next()); } } And then MyIterator should be implemented somehow: import java.util.Iterator; public class myIterator implements Iterator{ @Override public boolean hasNext() { // TODO Auto-generated method stub return false; } @Override public Object next() { // TODO Auto-generated method stub return null; } @Override public void remove() { // TODO Auto-generated method stub } } MyIterator should iterate arr from MyArray class, from start to end values; both are also attributes of MyArray. So, as MyIterator should use MyArray attributes, how should MyIterator be implemented? Perhaps I can send the current object in the initialization: it=new myIterator(this); But I guess it's not the best soultion. Or maybe MyArray itself should implement Iterator interface? How is this solved?

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• Tree iterator, can you optimize this any further?

  - by Ron

  As a follow up to my original question about a small piece of this code I decided to ask a follow up to see if you can do better then what we came up with so far. The code below iterates over a binary tree (left/right = child/next ). I do believe there is room for one less conditional in here (the down boolean). The fastest answer wins! The cnt statement can be multiple statements so lets make sure this appears only once The child() and next() member functions are about 30x as slow as the hasChild() and hasNext() operations. Keep it iterative <-- dropped this requirement as the recursive solution presented was faster. This is C++ code visit order of the nodes must stay as they are in the example below. ( hit parents first then the children then the 'next' nodes). BaseNodePtr is a boost::shared_ptr as thus assignments are slow, avoid any temporary BaseNodePtr variables. Currently this code takes 5897ms to visit 62200000 nodes in a test tree, calling this function 200,000 times. void processTree (BaseNodePtr current, unsigned int & cnt ) { bool down = true; while ( true ) { if ( down ) { while (true) { cnt++; // this can/will be multiple statesments if (!current->hasChild()) break; current = current->child(); } } if ( current->hasNext() ) { down = true; current = current->next(); } else { down = false; current = current->parent(); if (!current) return; // done. } } }

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• Accessing and manipulating lwpf listbox datatemplate elements

  - by black sensei

  Hello good people , i'm trying to achieve a functionality but i'm don't know how to start it. I'm using vs 2008 sp1 and i'm consuming a webservice which returns a collection (is contactInfo[]) that i bind to a ListBox with little datatemplate on it. <ListBox Margin="-146,-124,-143,-118.808" Name="contactListBox" MaxHeight="240" MaxWidth="300" MinHeight="240" MinWidth="300"> <ListBox.ItemTemplate> <DataTemplate> <TextBlock> <CheckBox Name="contactsCheck" Uid="{Binding fullName}" Checked="contacts_Checked" /><Label Content="{Binding fullName}" FontSize="15" FontWeight="Bold"/> <LineBreak/> <Label Content="{Binding mobile}" FontSize="10" FontStyle="Italic" Foreground="DimGray" /> <Label Content="{Binding email}" FontStyle="Italic" FontSize="10" Foreground="DimGray"/> </TextBlock> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Every works fine so far. so When a checkbox is checked i'll like to access the information of the labels (either the) belonging to the same row or attached to it and append the information to a global variable for example (for each checkbox checked). My problem right now is that i don't know how to do that. Can any one shed some light on how to do that? if you notice Checked="contacts_Checked" that's where i planned to perform the operations. thanks for reading and helping out

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• How to avoid the linebreak inside a word (Static Layout

  - by Addev

  I'm trying to make a text as big as I can making it fit a Rect. basically I use a StaticLayout for pre-calculate the text size and make it fit the Rect's height: // Since the width is fixed for the StaticLayout it should only fit the height while (currentHeight>Rect.getHeight()){ size-=2; } textPaint.setTextSize(size); The problem is that if the Rect is very high, the exit condition is reached but breaking the words (see the capture). Is there a way for avoid this? Goal: Actual: Current code: textSize=MAX_TEXT_SIZE do { if (textSize < mMinTextSize) { Log.i(TAG, "Min reached"); textSize = mMinTextSize; textPaint.setTextSize(textSize); fits = true; } else { textPaint.setTextSize(textSize); StaticLayout layout = new StaticLayout(text, textPaint, targetWidth, Alignment.ALIGN_NORMAL, 1.0, 0, true); layout.draw(canvas); float heightRatio= (float) layout.getHeight() / (float) targetHeight; boolean fitsHeight = heightRatio<= 1f; if (fitsHeight) { fits = true; } else { textSize -= 2; } } Log.i(TAG, "textSize=" + textSize + " fits=" + fits); } while (!fits); thanks

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• A specific data structure

  - by user550413

  Well, this question is a bit specific but I think there is some general idea in it that I can't get it. Lets say I got K servers (which is a constant that I know its size). I have a program that get requests and every request has an id and server id that will handle it. I have n requests - unknown size and can be any number. I need a data structure to support the next operations within the given complexity: GetServer - the function gets the request ID and returns the server id that is supposed to handle this request at the current situation and not necessarily the original server (see below). Complexity: O(log K) at average. KillServer - the function gets as input a server id that should be removed and another server id that all the requests of the removed server should be passed to. Complexity: O(1) at the worst case. -- Place complexity for all the structure is O(K+n) -- The KillServer function made me think using a Union-Find as I can do the union in O(1) as requested but my problem is the first operation. Why it's LogK? Actually, no matter how I "save" the requests if I want to access to any request (lets say it's an AVL tree) so the complexity will be O(log n) at the worst case and said that I can't assume Kn (and probably K Tried thinking about it a couple of hours but I can't find any solution. Known structures that can be used are: B+ tree, AVL tree, skip list, hash table, Union-Find, rank tree and of course all the basics like arrays and such.

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• localhost + staging + production environments?

  - by Kentor

  Hello, I have a website say www.livesite.com which is currently running. I have been developing a new version of the website on my local machine with http://localhost and then committing my changes with svn to www.testsite.com where I would test the site on the livesite.com server but under another domain (its the same environment as the live site but under a different domain). Now I am ready to release the new version to livesite.com. Doing it the first time is easy, I could just copy & paste everything from testsite.com to livesite.com (not sure its the best way to do it). I want to keep testsite.com as a testing site where I would push updates, test them and once satisfied move to livesite.com but I am not sure how to do that after the new site is launched.. I don't think copy pasting the whole directory is the right way of doing it and it will break the operations of current users on the livesite.com. I also want to keep my svn history on testsite.com. What is the correct way of doing this with SVN ? Thank you so much!

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• How to show alert in a jsp from a servlet and then redirect to another jsp?

  - by Xaul Omar Tobar

  I tried this but does not display the message only redirects login.jsp <form method="post" action="Login_Servlet" > <input name="idUsuario" type="text"/> <input name="password" type="password" /> <button type="submit">Entrar</button> </form> Login_Servlet response.setContentType("text/html;charset=UTF-8"); PrintWriter out = response.getWriter(); String userid= request.getParameter("idUser"); String password = request.getParameter("password"); Login_Service login_Service = new Login_Service(); boolean result = login_Servicio.aut(userid, password); Usuario user = login_Servicio.getUsuariosByUsuario(userid); if(result == true){ request.getSession().setAttribute("user", user); response.sendRedirect("vistas/Inicio.jsp"); } else{ out.println("<script type=\"text/javascript\">"); out.println("alert('User or password incorrect');"); out.println("</script>"); response.sendRedirect("index.jsp"); } Is it possible to display a message like this? if so I'm doing wrong?

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• Drawing line graphics leads Flash to spiral out of control!

  - by drpepper

  Hi, I'm having problems with some AS3 code that simply draws on a Sprite's Graphics object. The drawing happens as part of a larger procedure called on every ENTER_FRAME event of the stage. Flash neither crashes nor returns an error. Instead, it starts running at 100% CPU and grabs all the memory that it can, until I kill the process manually or my computer buckles under the pressure when it gets up to around 2-3 GB. This will happen at a random time, and without any noticiple slowdown beforehand. WTF? Has anyone seen anything like this? PS: I used to do the drawing within a MOUSE_MOVE event handler, which brought this problem on even faster. PPS: I'm developing on Linux, but reproduced the same problem on Windows. UPDATE: You asked for some code, so here we are. The drawing function looks like this: public static function drawDashedLine(i_graphics : Graphics, i_from : Point, i_to : Point, i_on : Number, i_off : Number) : void { const vecLength : Number = Point.distance(i_from, i_to); i_graphics.moveTo(i_from.x, i_from.y); var dist : Number = 0; var lineIsOn : Boolean = true; while(dist < vecLength) { dist = Math.min(vecLength, dist + (lineIsOn ? i_on : i_off)); const p : Point = Point.interpolate(i_from, i_to, 1 - dist / vecLength); if(lineIsOn) i_graphics.lineTo(p.x, p.y); else i_graphics.moveTo(p.x, p.y); lineIsOn = !lineIsOn; } } and is called like this (m_graphicsLayer is a Sprite): m_graphicsLayer.graphics.clear(); if (m_destinationPoint) { m_graphicsLayer.graphics.lineStyle(2, m_fixedAim ? 0xff0000 : 0x333333, 1); drawDashedLine(m_graphicsLayer.graphics, m_initialPos, m_destinationPoint, 10, 10); }

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• Calling a network State check from other activities

  - by Laurent

  I realize this question has been answered before but couldn't find an answer that deals with my specific case. I want to create a class called "InternetConnectionChecks" that will handle checking a network state and http timeouts. I'll call the methods twice in the app (once at the beginning to get data from a server, and once at the end to send user orders to the server). For good form I'd like to put all these methods in a single class rather than copy/paste at different points in my code. To check the network state, I'm using ConnectivityManager; thing is, getSystemService requires a class that extends Activity. package arbuckle.app; import android.app.Activity; import android.app.Service; import android.content.Context; import android.net.ConnectivityManager; import android.net.NetworkInfo; public class InternetConnectionChecks extends Activity { public boolean isNetworkAvailable(){ ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo(); if ((activeNetworkInfo != null)&&(activeNetworkInfo.isConnected())){ return true; }else{ return false; } } } QUESTION: if I call the method isNetworkAvailable from another activity, am I: - going to hit up serious errors. - violating good coding form? *If this isn't the right way to do things, can you point me in the right direction to set up a separate class I can call on to check internet connection? Thanks everyone!

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• Caching vector addition over changing collections

  - by DRMacIver

  I have the following setup: I have a largish number of uuids (currently about 10k but expected to grow unboundedly - they're user IDs) and a function f : id - sparse vector with 32-bit integer values (no need to worry about precision). The function is reasonably expensive (not outrageously so, but probably on the order of a few 100ms for a given id). The dimension of the sparse vectors should be assumed to be infinite, as new dimensions can appear over time, but in practice is unlikely to ever exceed about 20k (and individual results of f are unlikely to have more than a few hundred non-zero values). I want to support the following operations efficiently: add a new ID to the collection invalidate an existing ID retrieve sum f(id) in O(changes since last retrieval) i.e. I want to cache the sum of the vectors in a way that's reasonable to do incrementally. One option would be to support a remove ID operation and treat invalidation as a remove followed by an add. The problem with this is that it requires us to keep track of all the old values of f, which is expensive in space. I potentially need to use many instances of this sort of cached structure, so I would like to avoid that. The likely usage pattern is that new IDs are added at a fairly continuous rate and are frequently invalidated at first. Ids which have been invalidated recently are much more likely to be invalidated again than ones which have remained valid for a long time, but in principle an old Id can still be invalidated. Ideally I don't want to do this in memory (or at least I want a way that lets me save the result to disk efficiently), so an idea which lets me piggyback off an existing DB implementation of some sort would be especially appreciated.

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• How can I speed up a 1800-line PHP include? It's slowing my pageload down to 10sec/view

  - by somerandomguy

  I designed my code to put all important functions in a single PHP file that's now 1800 lines long. I call it in other PHP files--AJAX processors, for example--with a simple "require_once("codeBank.php")". I'm discovering that it takes about 10 seconds to load up all those functions, even though I have nothing more than a few global arrays and a bunch of other functions involved. The main AJAX processor code, for example, is taking 8 seconds just to do a simple syntax verification (whose operational function is stored in codeBank.php). When I comment out the require_once, my AJAX response time speeds up from 10sec to 40ms, so it's pretty clear that PHP's trying to do something with those 1800 lines of functions. That's even with APC installed, which is surprising. What should I do to get my code speed back to the sub-100ms level? Am I failing to get the cache's benefit somehow? Do I need to cut that single function bank file into different pieces? Are there other subtle things that I could be doing to screw up my response time? Or barring all that, what are some tools to dig further into which PHP operations are hitting speed bumps?

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• Is it possible to cache all the data in a SQL Server CE database using LinqToSql?

  - by DanM

  I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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• jquery: How to deal with 'this' in ajax callbacks

  - by Svish

  I currently have code similar to this for a form: $('#some-form') .submit(function() { // Make sure we are not already busy if($(this).data('busy')) return false; $(this).data('busy', true); // Do post $.post("some/url", $(this).serialize(), function(data) { if(data.success) // Success is a boolean I set in the result on the server { // Deal with data } else { // Display error } $('#some-form') .removeData('busy'); }); return false; }); My issue is that I would like to somehow remove the need for knowing the form id in the post callback. In the end where I remove the busy data from the form, I'd like to somehow not have that hard coded. Is there any way I can do this? Is there a way I can hand whatever is in this to the post callback function? Since I know the id right now, I can get around it by doing what I have done, but I'd like to know how to not be dependant on knowing the id, since often I don't have an id. (For example if I have a link in each row in a table and all the rows have the same click handler.

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• Matching Class arrays

  - by frinkz

  I'm writing a routine to invoke methods, found by a name and an array of parameter Class values Matching the Method by getName works, but when trying to match the given Class[] for parameters, and Method.getParameterTypes(), I'm having trouble. I assumed that this would work: Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); if(methodParams == searchParams) { m.invoke(this, paramValues); } But apparantly not - m.invoke is never reached. I've checked, and methodParams gives the same classes as searchParams. The code below works, and picks the right method, but it seems like a very dirty way of doing things, I'm sure I'm missing something obvious. Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); boolean isMatch = true; for(int i = 0; i < searchParams.length; i++) { if(!searchParams.getClass().equals(methodParams.getClass())) { isMatch = false; } } if(isMatch) { m.invoke(this, paramValues); }

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• What is a good "Error Checking" Pattern (Java)?

  - by Jack

  I'll explain what I mean by input error checking. Say you have a function doSomething(x). If the function completes successfully doSomething does something and returns nothing. However, if there are errors I'd like to be notified. That is what I mean by error checking. I'm looking for, in general, the best way to check for errors. I've thought of the following solutions, each with a potential problem. Flag error checking. If doSomething(x) completes successfully return null. Otherwise, it returns a boolean or an error string. Problem: Side effects. Throwing an exception. Throw an exception if doSomething(x) encounters an error. Problem: If you are performing error checking for parameters only, throwing an IllegalArgumentExceptionseems inappropriate. Validating input prior to function call. If the error checking is only meant for the parameters of the function, then you can call a validator function before calling the doSomething(x) function. Problem: What if a client of the class forgets to call the validator function before calling doSomething(x)? I often encounter this problem and any help or a point in the right direction would be much appreciated.

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