Search Results

Search found 16643 results on 666 pages for 'stackoverflow answer'.

Page 555/666 | < Previous Page | 551 552 553 554 555 556 557 558 559 560 561 562 | Next Page >

Business Objects - Containers or functional?

- by Walter

Where I work, we've gone back and forth on this subject a number of times and are looking for a sanity check. Here's the question: Should Business Objects be data containers (more like DTOs) or should they also contain logic that can perform some functionality on that object. Example - Take a customer object, it probably contains some common properties (Name, Id, etc), should that customer object also include functions (Save, Calc, etc.)? One line of reasoning says separate the object from the functionality (single responsibility principal) and put the functionality in a Business Logic layer or object. The other line of reasoning says, no, if I have a customer object I just want to call Customer.Save and be done with it. Why do I need to know about how to save a customer if I'm consuming the object? Our last two projects have had the objects separated from the functionality, but the debate has been raised again on a new project. Which makes more sense? EDIT These results are very similar to our debates. One vote to one side or another completely changes the direction. Does anyone else want to add their 2 cents? EDIT Eventhough the answer sampling is small, it appears that the majority believe that functionality in a business object is acceptable as long as it is simple but persistence is best placed in a separate class/layer. We'll give this a try. Thanks for everyone's input...

Read the article
What programming hack from your past are you most ashamed of?

- by LeopardSkinPillBoxHat

We've all been there (usually when we are young and inexperienced). Fixing it properly is too difficult, too risky or too time-consuming. So you go down the hack path. Which hack from your past are you most ashamed of, and why? I'm talking about the ones where you would be really embarrassed if someone could attribute the hack to you (quite easily if you are using revision control software). One hack per answer please. Mine was shortly after I started in my first job. I was working on a legacy C system, and there was this strange defect where a screen view failed to update properly under certain circumstances. I wasn't familiar with how to use the debugger at this time, so I added traces into the code to figure out what was going on. Then I realised that the defect didn't occur anymore with the traces in the code. I slowly backed out the traces one-by-one, until I realised that only a single trace was required to make the problem go away. My logic now would tell me that I was dealing with some sort of race-condition or timing related issue that the trace just "hid under the rug". But I checked in the code with the following line, and all was well: printf(""); Which hacks are you ashamed of?

Read the article
Pinax TemplateSyntaxError

- by Spikie

hi, i ran into this errors while trying to modify pinax database model i am using eclipse pydev i have this error on the pydev Exception Type: TemplateSyntaxError at / Exception Value: Caught an exception while rendering: (1146, "Table 'test1.announcements_announcement' doesn't exist") please how do i correct this UPDATE: i asked this question and left unresolved some months back and you what ran into the bug again this week and typed the error message in google hit the page with the question and unanswered so i think i have to answer it and hope it help someone in the future have the same problem. some the problem is that the sqlite path is out of place so django or this case pinax can not find it so to resolve that change the absolute path to sqlite like it DATABASE_ENGINE = 'sqlite3' # 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'ado_mssql'. DATABASE_NAME = os.path.join(PROJECT_ROOT,'dev.db' ) # Or path to database file if using sqlite3. DATABASE_USER = '' # Not used with sqlite3. DATABASE_PASSWORD = '' # Not used with sqlite3. DATABASE_HOST = '' # Set to empty string for localhost. Not used with sqlite3. DATABASE_PORT = '' # Set to empty string for default. Not used with sqlite3. i hope that help

Read the article
HOWTO - Compare a date string to datetime in SQL Server?

- by Guy

In SQL Server I have a DATETIME column which includes a time element. Example: '14 AUG 2008 14:23:019' What is the best method to only select the records for a particular day, ignoring the time part? Example: (Not safe, as it does not match the time part and returns no rows) DECLARE @p_date DATETIME SET @p_date = CONVERT( DATETIME, '14 AUG 2008', 106 ) SELECT * FROM table1 WHERE column_datetime = @p_date Note: Given this site is also about jotting down notes and techniques you pick up and then forget, I'm going to post my own answer to this question as DATETIME stuff in MSSQL is probably the topic I lookup most in SQLBOL. Update Clarified example to be more specific. Edit Sorry, But I've had to down-mod WRONG answers (answers that return wrong results). @Jorrit: WHERE (date>'20080813' AND date<'20080815') will return the 13th and the 14th. @wearejimbo: Close, but no cigar! badge awarded to you. You missed out records written at 14/08/2008 23:59:001 to 23:59:999 (i.e. Less than 1 second before midnight.)

Read the article
Virtual properties duplicated during serialization when XmlElement attribute used

- by Laramie

The Goal: XML serialize an object that contains a list of objects of that and its derived types. The resulting XML should not use the xsi:type attribute to describe the type, to wit the names of the serialized XML elements would be an assigned name specific to the derived type, not always that of the base class, which is the default behavior. The Attempt: After exploring IXmlSerializable and IXmlSerializable with eerie XmlSchemaProvider methods and voodoo reflection to return specialized schemas and an XmlQualifiedName over the course of days, I found I was able to use the simple [XmlElement] attribute to accomplish the goal... almost. The Problem: Overridden properties appear twice when serializing. The exception reads "The XML element 'overriddenProperty' from namespace '' is already present in the current scope. Use XML attributes to specify another XML name or namespace for the element." I attempted using a *Specified property (see code), but it didn't work. Sample Code: Class Declaration using System; using System.Collections.Generic; using System.Xml.Serialization; [XmlInclude(typeof(DerivedClass))] public class BaseClass { public BaseClass() { } [XmlAttribute("virt")] public virtual string Virtual { get; set; } [XmlIgnore] public bool VirtualSpecified { get { return (this is BaseClass); } set { } } [XmlElement(ElementName = "B", Type = typeof(BaseClass), IsNullable = false)] [XmlElement(ElementName = "D", Type = typeof(DerivedClass), IsNullable = false)] public List<BaseClass> Children { get; set; } } public class DerivedClass : BaseClass { public DerivedClass() { } [XmlAttribute("virt")] public override string Virtual { get { return "always return spackle"; } set { } } } Driver: BaseClass baseClass = new BaseClass() { Children = new List<BaseClass>() }; BaseClass baseClass2 = new BaseClass(){}; DerivedClass derivedClass1 = new DerivedClass() { Children = new List<BaseClass>() }; DerivedClass derivedClass2 = new DerivedClass() { Children = new List<BaseClass>() }; baseClass.Children.Add(derivedClass1); baseClass.Children.Add(derivedClass2); derivedClass1.Children.Add(baseClass2); I've been wrestling with this on and off for weeks and can't find the answer anywhere.

Read the article
What is the right approach to checksumming UDP packets

- by mr.b

I'm building UDP server application in C#. I've come across a packet checksum problem. As you probably know, each packet should carry some simple way of telling receiver if packet data is intact. Now, UDP already has 2-byte checksum as part of header, which is optional, at least in IPv4 world. Alternative method is to have custom checksum as part of data section in each packet, and to verify it on receiver. My question boils down to: is it better to rely on (optional) checksum in UDP packet header, or to make a custom checksum implementation as part of packet data section? Perhaps the right answer depends on circumstances (as usual), so one circumstance here is that, even though code is written and developed in .NET on Windows, it might have to run under platform-independent Mono.NET, so eventual solution should be compatible with other platforms. I believe that custom checksum algorithm would be easily portable, but I'm not so sure about the first one. Any thoughts? Also, shouts about packet checksumming in general are welcome.

Read the article
Integer Surrogate Key?

- by CitadelCSAlum

I need something real simple, that for some reason I am unable to accomplish to this point. I have also been unable to Google the answer surprisingly. I need to number the entries in different tables uniquely. I am aware of AUTO INCREMENT in MySQL and that it will be involved. My situation would be as follows If I had a table like Table EXAMPLE ID - INTEGER FIRST_NAME - VARCHAR(45) LAST_NAME - VARCHAR(45) PHONE - VARCHAR(45) CITY - VARCHAR(45) STATE - VARCHAR(45) ZIP - VARCHAR(45) This would be the setup for the table where ID is an integer that is auto-incremented every time an entry is inserted into the table. The thing I need is that I do not want to have to account for this field when inserting data into the database. From my understanding this would be a surrogate key, that I can tell the database to automatically increment and I do not have to include it in the INSERT STATEMENT so instead of INSERT INTO EXAMPLE VALUES (2,'JOHN','SMITH',333-333-3333,'NORTH POLE'.... I can leave out the first ID column and just write something like INSERT INTO EXAMPLE VALUES ('JOHN','SMITH'.....etc) Notice I Wouldnt have to define the ID column... I know this is a very common task to do, but for some reason I cant get to the bottom of it. I am using MySQL, just to clarify. Thanks alot

Read the article
jQuery Validation error...

- by Povylas

Hi, I have been struggling with this jQuery Validation Plugin. Here is the code: <script type="text/javascript"> $(function() { var validator = $('#signup').validate({ errorElement: 'span', rules: { username: { required: true, minlenght: 6 //remote: "check-username.php" }, password: { required: true, minlength: 5 }, confirm_password: { required: true, minlength: 5, equalTo: "#password" }, email: { required: true, email: true }, agree: "required" }, messages: { username: { required: "Please enter a username", minlength: "Your username must consist of at least 6 characters" //remote: "Somenoe have already chosen nick like this." }, password: { required: "Please provide a password", minlength: "Your password must be at least 5 characters long" }, confirm_password: { required: "Please provide a password", minlength: "Your password must be at least 5 characters long", equalTo: "Please enter the same password as above" }, email: "Please enter a valid email address", agree: "Please accept our policy" } }); var root = $("#wizard").scrollable({size: 1, clickable: false}); // some variables that we need var api = root.scrollable(); $("#data").click(function() { validator.form(); }); // validation logic is done inside the onBeforeSeek callback api.onBeforeSeek(function(event, i) { if($("#signup").valid() == false){ return false; }else{ return true; } $("#status li").removeClass("active").eq(i).addClass("active"); }); //if tab is pressed on the next button seek to next page root.find("button.next").keydown(function(e) { if (e.keyCode == 9) { // seeks to next tab by executing our validation routine api.next(); e.preventDefault(); } }); $('button.fin').click(function(){ parent.$.fn.fancybox.close() }); }); </script> And here is the error: $.validator.methods[method] is undefined http://www.vvv.vhost.lt/js/jquery-validate/jquery.validate.min.js Line 15 I am completely confused... Maybe some kind of handler is needed? I would be grateful for any kind of answer.

Read the article
Overriding equals method without breaking symmetry in a class that has a primary key

- by Kosta

Hi, the answer to this question is probably "not possible", but let me ask regardless :) Assuming we have a very simple JAVA class that has a primary key, for example: class Person { String ssid; String name; String address; ... } Now, I want to store people in a collection, meaning I will have to override the equals method. Not a completely trivial matter, but on a bare basis I will have something along the lines of: @Override public boolean equals (Object other) { if(other==this) return true; if(!other.getClass().equals(this.getClass()) return false; Person otherPerson = (Person)other; if(this.ssid.equals(otherPerson.getSsid()) return true; } Excuse any obvious blunders, just typing this out of my head. Now, let's say later on in the application I have a ssid I obtained through user input. If I want to compare my ssid to a Person, I would have to call something like: String mySsid = getFromSomewhere(); Person myPerson = getFromSomewhere(); if(myPerson.equals(new Person(mySsid)) doSomething(); This means I have to create a convenience constructor to create a Person based on ssid (if I don't already have one), and it's also quite verbose. It would be much nicer to simply call myPerson.equals(mySsid) but if I added a string comparison to my Person equals class, that would break the symmetry property, since the String hasn't got a clue on how to compare itself to a Person. So finally, the big question, is there any way to enable this sort of "shorthand" comparisons using the overriden equals method, and without breaking the symmetry rule? Thanks for any thoughts on this!

Read the article
Good Learning Method for Objective-C?

- by Josh Kahane

Hi I know this must be asked a millions times and can't be easy to answer as there is o definitive method, but any help would be appreciated, thanks. I have been playing around with all sorts of things in Xcode and with Objective-C, however I can't seem to find a good way of learning things in an efficient way. I have bought the book 'Programming in Objective-C 2.0' and its great but just lays down the basics it seems. I want to learn in the 2D game development direction, then of course 3D after nailing that, if thats the right thing to do? I am 17 currently in year 13, last year of school/A Levels and am almost definitely taking a gap year. Any good, well known reputable courses online or offline (real world)? This is my first programming language, and I am absolutely serious about learning this. One last question, is when learning things online, I have in the past started building a feature and learning a certain aspect in programming only to find out after adding more its slows down the app or its to inefficient. Is the key to use a certain method in a certain situation (being os many ways to do the same thing) or use any of those methods and refine it in your app to make it run smoothly? Sorry, its hard for me to know when I have little experience, thus far. Sorry for rambling on! I would appreciate any help, thank you!

Read the article
Parse XML function names and call within whole assembly

- by Matt Clarkson

Hello all, I have written an application that unit tests our hardware via a internet browser. I have command classes in the assembly that are a wrapper around individual web browser actions such as ticking a checkbox, selecting from a dropdown box as such: BasicConfigurationCommands EventConfigurationCommands StabilizationCommands and a set of test classes, that use the command classes to perform scripted tests: ConfigurationTests StabilizationTests These are then invoked via the GUI to run prescripted tests by our QA team. However, as the firmware is changed quite quickly between the releases it would be great if a developer could write an XML file that could invoke either the tests or the commands: <?xml version="1.0" encoding="UTF-8" ?> <testsuite> <StabilizationTests> <StressTest repetition="10" /> </StabilizationTests> <BasicConfigurationCommands> <SelectConfig number="2" /> <ChangeConfigProperties name="Weeeeee" timeOut="15000" delay="1000"/> <ApplyConfig /> </BasicConfigurationCommands> </testsuite> I have been looking at the System.Reflection class and have seen examples using GetMethod and then Invoke. This requires me to create the class object at compile time and I would like to do all of this at runtime. I would need to scan the whole assembly for the class name and then scan for the method within the class. This seems a large solution, so any information pointing me (and future readers of this post) towards an answer would be great! Thanks for reading, Matt

Read the article
Sending email through a Google Apps account is working locally, but not on my web server...

- by Janis Baldwin

Related: Send Email via C# through Google Apps account My question is the same so I implemented Koistya's solution as follows. The heartbreak is that it works beautifully on my dev laptop but when ported to web server it times out with no explanation. My SMTP config is in my web.config file. I made mods based on Koistya's answer: <mailSettings> **Changed** <smtp from="[email protected]"> <network host="smtp.gmail.com" password="[password]" port="587" userName="[email protected]"/> </smtp> **Original**  </mailSettings> My .Net C# code (before & after removed): SmtpClient mSmtpClient = new SmtpClient(); mSmtpClient.EnableSsl = true; mSmtpClient.Send(message); As I said this works great on my dev environment but not on web. Can anyone help? Thanks.

Read the article
Photoshop CS5 not recognising activeDocument

- by Max Kielland

I wrote a quite big script for Photoshop CS5.1 on my 64bit Vista machine. Now when I run the very same script on my new 64bit Windows 7 machine, Adobe ExtendScript Tool complains about activeDocument (no such element) in this simple script: #target photoshop var pDoc = app.activeDocument; alert("Done!"); I have tried both and without #target and choosing the target in the ExtendedScript Tool. Is there something I have missed, or do I need to install something more. I only installed the 64bit version of Photoshop. Is it so that the 32bit Photoshop has the script extensions? I don't see why I need to install both 32bit and 64bit versions if I'm only going to use the 64bit version. EDIT I installed the 32bit version as well. Tried the same script against 32 and 64 bit, still no difference. SOLVED The mystery is solved. It is embarrassing simple if you interpret the error message more careful. Of course I can't get an activeDocument if there are no documents in Photoshop, duh!?! I interpreted it as the statement activeDocument wasn't recognised, but of course if I have no document there is no such element (as a photoshop document) to give me. I'm used to C++ and would expect the reuslt to be a NULL value or similar if there is a problem to get the document... excuses, excuses ;) Well, if someone else should get into the same problem, here is the answer on my expense :D

Read the article
How to detect back button or forward button navigation in a silverlight navigation application

- by parapura rajkumar

When a Page is navigated to in silverlight you can override this method. protected override void OnNavigatedTo(NavigationEventArgs e) { base.OnNavigatedTo(e); } The NavigationEventArgs has a NavigationMode enumeration which is defined as public enum NavigationMode { New = 0, Back = 1, Forward = 2, Refresh = 3, } But calling e.NavigationMode always throws a NotImplementedException Is there a way in silverlight to detect a page is being navigated to because the user hit the forward/back browser button. What I am trying to achieve is some kind of state that can be preserved when the user hits the back button. For example assume you have a customer page which is showing a list of customers in a datagrid. The user can select a customer and there is a detail view which shows all the orders for that customer. Now within an order item you can click a hyperlink link that takes you to the shipping history of the order which is a separate page. When the user hits the back button I want to go back to the customers page and automatically select the customer he was viewing. Is this possible at all ? I also tried out the fragment navigation feature NavigationService.Navigate(new Uri("#currentcustomerid=" + customer.Id.ToString(), UriKind.Relative)); when the customer selection changes but this adds too many items to the history when the user clicks various customers on the customer page. EDIT There is also an method you can override protected override void OnNavigatingFrom(NavigatingCancelEventArgs e) { } which is the same as handling the NavigationService.Navigating event as indicated by BugFinder's answer. In this method e.NavigationMode always returns New when when you hit the Back or Forward Button. The only time this method returns Back is when you explicitly call NavigationService.GoBack()

Read the article
How to disable vertical bounce/scroll on iPhone in a mobile web application

- by Kasper Skov

As the title says, i need to disable vertical bounce on iphone on my mobile web form application. Ive tried alot of different things, but most of them disables my form or horizontal scroll and bounce as well. Any ideas? Im using jquery.mobile btw :) Update: I actually managed to get the code from the first answer working somewhat: function stopScrolling( touchEvent ) { touchEvent.preventDefault(); } document.addEventListener( 'touchstart' , stopScrolling , false ); document.addEventListener( 'touchmove' , stopScrolling , false ); The reason why I couldnt get it to work in the first place, was that there actually was some margin on my body (stupid me). But. As the layout is fluid and im using jquery.mobile and have <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"> in the header (I think) it doesnt work properly. The page is zoomed out (view from like a desktop browser) and zooming is disabled. Without the code, the page scales perfectly right from an 50" tv to the smallest nokia on the planet. Am I doing something wrong? Im starting to think the problem is caused by the body/content somehow being over 100% of the viewport. No idea how though.

Read the article
Most efficient way to check for DBNull and then assign to a variable?

- by ilitirit

This question comes up occasionally but I haven't seen a satisfactory answer. A typical pattern is (row is a DataRow): if (row["value"] != DBNull.Value) { someObject.Member = row["value"]; } My first question is which is more efficient (I've flipped the condition): row["value"] == DBNull.Value; // Or row["value"] is DBNull; // Or row["value"].GetType() == typeof(DBNull) // Or... any suggestions? This indicates that .GetType() should be faster, but maybe the compiler knows a few tricks I don't? Second question, is it worth caching the value of row["value"] or does the compiler optimize the indexer away anyway? eg. object valueHolder; if (DBNull.Value == (valueHolder = row["value"])) {} Disclaimers: row["value"] exists. I don't know the column index of the column (hence the column name lookup) I'm asking specifically about checking for DBNull and then assignment (not about premature optimization etc). Edit: I benchmarked a few scenarios (time in seconds, 10000000 trials): row["value"] == DBNull.Value: 00:00:01.5478995 row["value"] is DBNull: 00:00:01.6306578 row["value"].GetType() == typeof(DBNull): 00:00:02.0138757 Object.ReferenceEquals has the same performance as "==" The most interesting result? If you mismatch the name of the column by case (eg. "Value" instead of "value", it takes roughly ten times longer (for a string): row["Value"] == DBNull.Value: 00:00:12.2792374 The moral of the story seems to be that if you can't look up a column by it's index, then ensure that the column name you feed to the indexer matches the DataColumn's name exactly. Caching the value also appears to be nearly twice as fast: No Caching: 00:00:03.0996622 With Caching: 00:00:01.5659920 So the most efficient method seems to be: object temp; string variable; if (DBNull.Value != (temp = row["value"]) { variable = temp.ToString(); } This was a good learning experience.

Read the article
Rendering LaTeX on third-party websites?

- by A. Rex

There are some sites on the web that render LaTeX into some more readable form, such as Wikipedia, some Wordpress blogs, and MathOverflow. They may use images, MathML, jsMath, or something like that. There are other sites on the web where LaTeX appears inline and is not rendered, such as the arXiv, various math forums, or my email. In fact, it is quite common to see an arXiv paper's abstract with raw LaTeX in it, e.g. this paper. Is there a plugin available for Firefox, or would it be possible to write one, that renders LaTeX within pages that do not provide a rendering mechanism themselves? (The LaTeX would be enclosed within dollar signs, e.g. $\pi$. See the arXiv link above.) Some notes: It may be impossible to render some of the code, because authors often copy-paste code directly from their source TeX files, which may contain things like "\cite{foo}" or undefined commands. These should be left alone. This question is a repost of a question from MathOverflow that was closed for not being related to math. There is one answer there, which is helpful, but perhaps Stack Overflow can provide better answers. I program a lot, but Javascript is not my specialty, so comments along the lines of "look at this library" are not particularly helpful to me (but may be to others).

Read the article
Java Simple Calculator

- by Lahiru Kavinda

I have made this calculator program in Java. This works well only when two numbers are calculated at one time. That means to get the sum of 1+2+3 you have to go this way : press 1 press + press 2 press = press + press 3 press = and it calculates it as 6. But I want to program this so that I can get the answer by: press 1 press + press 2 press + press 3 press = but this gives the answer 5!!! How to code this so that it works like an ordinary calculator? Here is my code: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class cal1 extends JFrame { double op1 = 0d, op2 = 0d; double result = 0d; char action; boolean b = false; boolean pressequal = false; public cal1() { makeUI(); } private void makeUI() { setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setSize(400, 400); b0 = new JButton("0"); b1 = new JButton("1"); b2 = new JButton("2"); b3 = new JButton("3"); b4 = new JButton("4"); b5 = new JButton("5"); b6 = new JButton("6"); b7 = new JButton("7"); b8 = new JButton("8"); b9 = new JButton("9"); bDot = new JButton("."); bMul = new JButton("*"); bDiv = new JButton("/"); bPlus = new JButton("+"); bMinus = new JButton("-"); bEq = new JButton("="); t = new JTextField(12); t.setFont(new Font("Tahoma", Font.PLAIN, 24)); t.setHorizontalAlignment(JTextField.RIGHT); numpad = new JPanel(); display = new JPanel(); numpad.add(b7); numpad.add(b8); numpad.add(b9); numpad.add(bMul); numpad.add(b4); numpad.add(b5); numpad.add(b6); numpad.add(bDiv); numpad.add(b1); numpad.add(b2); numpad.add(b3); numpad.add(bMinus); numpad.add(bDot); numpad.add(b0); numpad.add(bEq); numpad.add(bPlus); numpad.setLayout(new GridLayout(4, 5, 5, 4)); display.add(t); add(display, BorderLayout.NORTH); add(numpad, BorderLayout.CENTER); t.addKeyListener(new KeyAdapter() { @Override public void keyTyped(KeyEvent e) { typeOnt(e); } }); b0.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b0pressed(e); } }); b1.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b1pressed(e); } }); b2.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b2pressed(e); } }); b3.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b3pressed(e); } }); b4.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b4pressed(e); } }); b5.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b5pressed(e); } }); b6.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b6pressed(e); } }); b7.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b7pressed(e); } }); b8.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b8pressed(e); } }); b9.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { b9pressed(e); } }); bDot.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bDotpressed(e); } }); bPlus.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bPlusPressed(e); } }); bMinus.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bMinusPressed(e); } }); bMul.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bMulPressed(e); } }); bDiv.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bDivPressed(e); } }); bEq.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { bEqpressed(e); } }); } void typeOnt(KeyEvent e) { e.consume(); } void b0pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "0"); } else { t.setText(t.getText() + "0"); } } void b1pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "1"); } else { t.setText(t.getText() + "1"); } } void b2pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "2"); } else { t.setText(t.getText() + "2"); } } void b3pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "3"); } else { t.setText(t.getText() + "3"); } } void b4pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "4"); } else { t.setText(t.getText() + "4"); } } void b5pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "5"); } else { t.setText(t.getText() + "5"); } } void b6pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "6"); } else { t.setText(t.getText() + "6"); } } void b7pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "7"); } else { t.setText(t.getText() + "7"); } } void b8pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "8"); } else { t.setText(t.getText() + "8"); } } void b9pressed(ActionEvent e) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "9"); } else { t.setText(t.getText() + "9"); } } void bDotpressed(ActionEvent e) { if (!t.getText().contains(".")) { if (b) { t.setText(null); b = false; t.setText(t.getText() + "0."); } else if (t.getText().isEmpty()) { t.setText("0."); } else { t.setText(t.getText() + "."); } } } void bPlusPressed(ActionEvent e) { b = true; action = '+'; op1 = Double.parseDouble(t.getText()); } void bMinusPressed(ActionEvent e) { b = true; action = '-'; op1 = Double.parseDouble(t.getText()); } void bMulPressed(ActionEvent e) { b = true; action = '*'; op1 = Double.parseDouble(t.getText()); } void bDivPressed(ActionEvent e) { b = true; action = '/'; op1 = Double.parseDouble(t.getText()); } void bEqpressed(ActionEvent e) { op2 = Double.parseDouble(t.getText()); doCal(); } void doCal() { switch (action) { case '+': result = op1 + op2; break; case '-': result = op1 - op2; break; case '*': result = op1 * op2; break; case '/': result = op1 / op2; break; } t.setText(String.valueOf(result)); } public static void main(String[] args) { new cal1().setVisible(true); } JButton b0; JButton b1; JButton b2; JButton b3; JButton b4; JButton b5; JButton b6; JButton b7; JButton b8; JButton b9; JButton bDot; JButton bPlus; JButton bMinus; JButton bMul; JButton bDiv; JButton bEq; JPanel display; JPanel numpad; JTextField t; }

Read the article
Dynamically created operators

- by Gero

I created a program using dev-cpp and wxwidgets which solves a puzzle. The user must fill the operations blocks and the results blocks, and the program will solve it. Im solving it using bruteforce, i generate all non repeated 9 length number combinations using a recursive algorithm. It does it pretty fast. Up to here all is great! But the problem is when my program operates depending the character on the blocks. Its extremely slow (it never gets the answer), because of the chars comparation against +, -, *, etc. Im doing a CASE. Is there some way or some programming language wich allows dinamic creation of operators? So i can define the operator ROW1COL2 to be a +, and the same way to all other operations. I leave a screenshot of the app, so its easier to understand how the puzzle works. http://www.imageshare.web.id/images/9gg5cev8vyokp8rhlot9.png PD: The algorithm works, i tryed it with a trivial puzzle, and solved it in a second.

Read the article
How does this code break the Law of Demeter?

- by Dave Jarvis

The following code breaks the Law of Demeter: public class Student extends Person { private Grades grades; public Student() { } /** Must never return null; throw an appropriately named exception, instead. */ private synchronized Grades getGrades() throws GradesException { if( this.grades == null ) { this.grades = createGrades(); } return this.grades; } /** Create a new instance of grades for this student. */ protected Grades createGrades() throws GradesException { // Reads the grades from the database, if needed. // return new Grades(); } /** Answers if this student was graded by a teacher with the given name. */ public boolean isTeacher( int year, String name ) throws GradesException, TeacherException { // The method only knows about Teacher instances. // return getTeacher( year ).nameEquals( name ); } private Grades getGradesForYear( int year ) throws GradesException { // The method only knows about Grades instances. // return getGrades().getForYear( year ); } private Teacher getTeacher( int year ) throws GradesException, TeacherException { // This method knows about Grades and Teacher instances. A mistake? // return getGradesForYear( year ).getTeacher(); } } public class Teacher extends Person { public Teacher() { } /** * This method will take into consideration first name, * last name, middle initial, case sensitivity, and * eventually it could answer true to wild cards and * regular expressions. */ public boolean nameEquals( String name ) { return getName().equalsIgnoreCase( name ); } /** Never returns null. */ private synchronized String getName() { if( this.name == null ) { this.name == ""; } return this.name; } } Questions How is the LoD broken? Where is the code breaking the LoD? How should the code be written to uphold the LoD?

Read the article
Connect from java mobile application to webservice to read messages.

- by Alexandru Trandafir Catalin

Hello, I have a website where users can send personal messages between them, now I want them to recieve the messages also on their mobile phone but without having to send them a SMS. I am thinking about providing them with a mobile phone with internet access over GPRS or 3G, then develop a Java application that will connect to the website and retrieve the messages. On the website I am thinking to make a webservice where the phone will login, get new messages, and also be able to answer back to messages. Does anyone know any mobile application tutorial that will do that? Or do you recommend me where to start? I never done a java mobile application before, I only work with websites and PHP. I also tried to use ICQ, the client is already done for java and for iphone, and I've also found a script that will send ICQ messages from PHP, but ICQ server bans you for 20 minutes when you do many reconnections, so I have to develop some kind of ICQ bot always online that will check for new messages to send from the mySQL database and then send them, one per 2-3 seconds, so the server won't ban me for flooding. Well any advice or recommendation is welcome about how to have users connected to the website messaging system from their phones. Thank you!

Read the article
Mysql - Help me alter this search query to get desired results

- by sandeepan-nath

Following is a dump of the tables and data needed to answer understand the system:- The system consists of tutors and classes. The data in the table All_Tag_Relations stores tag relations for each tutor registered and each class created by a tutor. The tag relations are used for searching classes. CREATE TABLE IF NOT EXISTS `Tags` ( `id_tag` int(10) unsigned NOT NULL auto_increment, `tag` varchar(255) default NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `Tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); CREATE TABLE IF NOT EXISTS `All_Tag_Relations` ( `id_tag` int(10) unsigned NOT NULL default '0', `id_tutor` int(10) default NULL, `id_wc` int(10) unsigned default NULL, KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `All_Tag_Relations` (`id_tag`, `id_tutor`, `id_wc`) VALUES (1, 1, NULL), (2, 1, NULL), (3, 1, 1), (4, 1, 1), (6, 2, NULL), (7, 2, NULL), (5, 2, 2), (4, 2, 2); Following is my query:- This query searches for "first class" (tag for first = 3 and for class = 4, in Tags table) and returns all those classes such that both the terms first and class are present in the class name. SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =3)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =3 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 And it returns the class with id_wc = 1. But, I want the search to show all those classes such that all the search terms are present in the class name or its tutor name So that searching "Sandeepan class" (wtagrels.id_tag = 1,4) or "Sandeepan Nath" also returns the class with id_wc=1. And Searching. Searching "Bob First" should not return any classes. Please modify the above query or suggest a new query, if possible using MyIsam - fulltext search, but somehow help me get the result.

Read the article
Problem mapping HttpHandler --> HTTP Error 404 Not Found

- by JohnIdol

I am having problems trying to map an HttpHandler in the web.config. This is the relevant config bit: <httpHandlers> <add verb="*" path="*.hndlr" type="MyAssembly.MyHandler, MyAssembly" validate="false" /> </httpHandlers> When I navigate to http://localhost/myApp/whatever.hndlr I am getting a server error 404 (not found). It's the 1st time I am hooking up an HttpHandler so I might be missing something - any help appreciated! UPDATE: I managed to get it working using both answers so far - who's able to exaplin why it works gets the answer marked! This is my config (won't work if Don't have both - I am running IIS7 in classic mode) System.web: <httpHandlers> <add verb="*" path="*MyHandler.hndlr" type="MyAssembly.MyAssemblyHandler, MyAssembly" validate="false"/> </httpHandlers> System.webserver: <handlers> <add name="MyHandler" verb="*" path="*MyHandler.hndlr" type="MyAssembly.MyAssemblyHandler, MyAssembly" validate="false"/> </handlers>

Read the article
Neural Network with softmax activation

- by Cambium

This is more or less a research project for a course, and my understanding of NN is very/fairly limited, so please be patient :) ============== I am currently in the process of building a neural network that attempts to examine an input dataset and output the probability/likelihood of each classification (there are 5 different classifications). Naturally, the sum of all output nodes should add up to 1. Currently, I have two layers, and I set the hidden layer to contain 10 nodes. I came up with two different types of implementations 1) Logistic sigmoid for hidden layer activation, softmax for output activation 2) Softmax for both hidden layer and output activation I am using gradient descent to find local maximums in order to adjust the hidden nodes' weights and the output nodes' weights. I am certain in that I have this correct for sigmoid. I am less certain with softmax (or whether I can use gradient descent at all), after a bit of researching, I couldn't find the answer and decided to compute the derivative myself and obtained softmax'(x) = softmax(x) - softmax(x)^2 (this returns an column vector of size n). I have also looked into the MATLAB NN toolkit, the derivative of softmax provided by the toolkit returned a square matrix of size nxn, where the diagonal coincides with the softmax'(x) that I calculated by hand; and I am not sure how to interpret the output matrix. I ran each implementation with a learning rate of 0.001 and 1000 iterations of back propagation. However, my NN returns 0.2 (an even distribution) for all five output nodes, for any subset of the input dataset. My conclusions: o I am fairly certain that my gradient of descent is incorrectly done, but I have no idea how to fix this. o Perhaps I am not using enough hidden nodes o Perhaps I should increase the number of layers Any help would be greatly appreciated! The dataset I am working with can be found here (processed Cleveland): http://archive.ics.uci.edu/ml/datasets/Heart+Disease

Read the article
How do I programmatically create a bootable CD?

- by Nicholas Flynt

I'm using a barebones tutorial as the basis for an OS I'm working on, and it seems to be an older tutorial: it has be compiling the kernel down to a floppy image, and then loading it with GRUB. Basically, I still want to use GRUB, but I'd like to have my OS run from a CD instead. The main reason is that I don't actually have a real floppy drive available (I'm testing in VirtualBox currently) and I thus have no way to test my OS on real hardware. I've been poking around on the net, and I can find lots of utilities that create a bootable CD from a floppy image, but these all seem to require an actual floppy drive, plus it's not really what I'm looking for. I'd like to be able to end up with a bootable CD during my make step ideally, without needing to first place the image on a floppy, which seems rather pointless. I guess the easy way to answer this: How do I set up GRUB to read my kernel image from a CD? Will I need a special utility to do this from Windows? (The kernel can't compile itself yet, that's not for a looong while) Thanks!

Read the article

< Previous Page | 551 552 553 554 555 556 557 558 559 560 561 562 | Next Page >