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  • SQL SERVER – Validating Spatial Object as NULL using IsNULL

    - by pinaldave
    Follow up questions are the most fun part of writing a blog post. Earlier I wrote about SQL SERVER – Validating Spatial Object with IsValidDetailed Function and today I received a follow up question on the same subject. The question was mainly about how NULL is handled by spatial functions. Well, NULL is NULL. It is very easy to work with NULL. There are two different ways to validate if the passed in the value is NULL or not. 1) Using IsNULL Function IsNULL function validates if the object is null or not, if object is not null it will return you value 0 and if object is NULL it will return you the value NULL. DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.ISNULL ObjIsNull GO DECLARE @p GEOMETRY = NULL SELECT @p.ISNULL ObjIsNull GO 2) Using IsValidDetailed Function IsValidateDetails function validates if the object is valid or not. If the object is valid it will return 24400: Valid but if the object is not valid it will give message with the error number. In case object is NULL it will return the value as NULL. DECLARE @p GEOMETRY = 'Polygon((2 2, 3 3, 4 4, 5 5, 6 6, 2 2))' SELECT @p.IsValidDetailed() IsValid GO DECLARE @p GEOMETRY = NULL SELECT @p.IsValidDetailed() IsValid GO When to use what? Now you can see that there are two different ways to validate the NULL values. I personally have no preference about using one over another. However, there is one clear difference between them. In case of the IsValidDetailed Function the return value is nvarchar(max) and it is not always possible to compare the value with nvarchar(max). Whereas the ISNULL function returns the bit value of 0 when the object is null and it is easy to determine if the object is null or not in the case of ISNULL function. Additionally, ISNULL function does not check if the object is valid or not and will return the value 0 if the object is not NULL. Now you know even though either of the function can be used in place of each other both have very specific use case. Use the one which fits your business case. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Spatial Database, SQL Spatial

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  • Upgraded Linux, now CMS Made Simple is spewing errors

    - by Paul Tomblin
    I upgraded my host from Debian Lenny to Debian Squeeze, and now my CMS Made Simple site is spewing PHP errors all over the screen. I thought I'd upgrade the CMS because I haven't done so in a while, but Google Chrome tells me that the CMS Made Simple site is infested with malware. What are my options now? Example errors: Deprecated: Assigning the return value of new by reference is deprecated in /www/danmurn/cms/include.php on line 73 Deprecated: Assigning the return value of new by reference is deprecated in /www/danmurn/cms/include.php on line 162 Deprecated: Assigning the return value of new by reference is deprecated in /www/danmurn/cms/include.php on line 240 Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /www/danmurn/cms/include.php:73) in /www/danmurn/cms/include.php on line 34 Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /www/danmurn/cms/include.php:73) in /www/danmurn/cms/include.php on line 34 Deprecated: Function set_magic_quotes_runtime() is deprecated in /www/danmurn/cms/include.php on line 62 Deprecated: Assigning the return value of new by reference is deprecated in /www/danmurn/cms/lib/classes/class.global.inc.php on line 184 Deprecated: Assigning the return value of new by reference is deprecated in /www/danmurn/cms/lib/classes/class.global.inc.php on line 196

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  • A Reusable Builder Class for Javascript Testing

    - by Liam McLennan
    Continuing on my series of builders for C# and Ruby here is the solution in Javascript. This is probably the implementation with which I am least happy. There are several parts that did not seem to fit the language. This time around I didn’t bother with a testing framework, I just append some values to the page with jQuery. Here is the test code: var initialiseBuilder = function() { var builder = builderConstructor(); builder.configure({ 'Person': function() { return {name: 'Liam', age: 26}}, 'Property': function() { return {street: '127 Creek St', manager: builder.a('Person') }} }); return builder; }; var print = function(s) { $('body').append(s + '<br/>'); }; var build = initialiseBuilder(); // get an object liam = build.a('Person'); print(liam.name + ' is ' + liam.age); // get a modified object liam = build.a('Person', function(person) { person.age = 999; }); print(liam.name + ' is ' + liam.age); home = build.a('Property'); print(home.street + ' manager: ' + home.manager.name); and the implementation: var builderConstructor = function() { var that = {}; var defaults = {}; that.configure = function(d) { defaults = d; }; that.a = function(type, modifier) { var o = defaults[type](); if (modifier) { modifier(o); } return o; }; return that; }; I still like javascript’s syntax for anonymous methods, defaults[type]() is much clearer than the Ruby equivalent @defaults[klass].call(). You can see the striking similarity between Ruby hashes and javascript objects. I also prefer modifier(o) to the equivalent Ruby, yield o.

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  • JDBC Triggers

    - by Tim Dexter
    Received a question from a customer last week, they were using the new rollup patch on top of 10.1.3.4.1. What are these boxes for? Don't you know? Surely? Well, they are for ... that new functionality, you know it's in the user docs, that thingmabobby doodah. OK, I dont know either, I can have a guess but let me check first. Serveral IM sessions, emails and a dig through the readme for the new patch and I had my answer. Its not in the official documentation, yet. Leslie is on the case. The two fields were designed to allow an Admin to set a users context attributes before a connection is made to a database and for un-setting the attributes after the connection is broken by the extraction engine. We got a sample from the Enterprise Manager team on how they will be using it with their VPD connections. FUNCTION bip_to_em_user (user_name_in IN VARCHAR2) RETURN BOOLEAN IS BEGIN SETEMUSERCONTEXT(user_name_in, MGMT_USER.OP_SET_IDENTIFIER); return TRUE; END bip_to_em_user; And used in the jdbc data source definition like this (pre-process function): sysman.mgmt_bip.bip_to_em_user(:xdo_user_name) You, of course can call any function that is going to return a boolean value, another example might be. FUNCTION set_per_process_username (username_in IN VARCHAR2) RETURN BOOLEAN IS BEGIN SETUSERCONTEXT(username_in); return TRUE; END set_per_process_username Just use your own function/package to set some user context. Very grateful for the mail from Leslie on the EM team's usage but I had to try it out. Rather than set up a VPD, I opted for a simpler test. Can I log the comings and goings of users and their queries using the same pre-process text box. Reaching back into the depths of my developer brain to remember some pl/sql, it was not that deep and I came up with: CREATE OR REPLACE FUNCTION BIPTEST (user_name_in IN VARCHAR2, smode IN VARCHAR2) RETURN BOOLEAN AS BEGIN INSERT INTO LOGTAB VALUES(user_name_in, sysdate,smode); RETURN true; END BIPTEST; To call it in the pre-fetch trigger. BIPTEST(:xdo_user_name) Not going to set the pl/sql world alight I know, but you get the idea. As a new connection is made to the database its logged in the LOGTAB table. The SMODE value just sets if its an entry or an exit. I used the pre- and post- boxes. NAME UPDATE_DATE S_FLAG oracle 14-MAY-10 09.51.34.000000000 AM Start oracle 14-MAY-10 10.23.57.000000000 AM Finish administrator 14-MAY-10 09.51.38.000000000 AM Start administrator 14-MAY-10 09.51.38.000000000 AM Finish oracle 14-MAY-10 09.51.42.000000000 AM Start oracle 14-MAY-10 09.51.42.000000000 AM Finish It works very well, I had some fun trying to find a nasty query for the extraction engine so that the timestamps from in to out actually had a difference. That engine is fast! The only derived value you can pass from BIP is :xdo_user_name. None of the other server values are available. Connection pools are not currently supported but planned for a future release. Now you know what those fields are for and look for some official documentation, rather than my ramblings, coming soon!

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  • Avoiding new operator in JavaScript -- the better way

    - by greengit
    Warning: This is a long post. Let's keep it simple. I want to avoid having to prefix the new operator every time I call a constructor in JavaScript. This is because I tend to forget it, and my code screws up badly. The simple way around this is this... function Make(x) { if ( !(this instanceof arguments.callee) ) return new arguments.callee(x); // do your stuff... } But, I need this to accept variable no. of arguments, like this... m1 = Make(); m2 = Make(1,2,3); m3 = Make('apple', 'banana'); The first immediate solution seems to be the 'apply' method like this... function Make() { if ( !(this instanceof arguments.callee) ) return new arguments.callee.apply(null, arguments); // do your stuff } This is WRONG however -- the new object is passed to the apply method and NOT to our constructor arguments.callee. Now, I've come up with three solutions. My simple question is: which one seems best. Or, if you have a better method, tell it. First – use eval() to dynamically create JavaScript code that calls the constructor. function Make(/* ... */) { if ( !(this instanceof arguments.callee) ) { // collect all the arguments var arr = []; for ( var i = 0; arguments[i]; i++ ) arr.push( 'arguments[' + i + ']' ); // create code var code = 'new arguments.callee(' + arr.join(',') + ');'; // call it return eval( code ); } // do your stuff with variable arguments... } Second – Every object has __proto__ property which is a 'secret' link to its prototype object. Fortunately this property is writable. function Make(/* ... */) { var obj = {}; // do your stuff on 'obj' just like you'd do on 'this' // use the variable arguments here // now do the __proto__ magic // by 'mutating' obj to make it a different object obj.__proto__ = arguments.callee.prototype; // must return obj return obj; } Third – This is something similar to second solution. function Make(/* ... */) { // we'll set '_construct' outside var obj = new arguments.callee._construct(); // now do your stuff on 'obj' just like you'd do on 'this' // use the variable arguments here // you have to return obj return obj; } // now first set the _construct property to an empty function Make._construct = function() {}; // and then mutate the prototype of _construct Make._construct.prototype = Make.prototype; eval solution seems clumsy and comes with all the problems of "evil eval". __proto__ solution is non-standard and the "Great Browser of mIsERY" doesn't honor it. The third solution seems overly complicated. But with all the above three solutions, we can do something like this, that we can't otherwise... m1 = Make(); m2 = Make(1,2,3); m3 = Make('apple', 'banana'); m1 instanceof Make; // true m2 instanceof Make; // true m3 instanceof Make; // true Make.prototype.fire = function() { // ... }; m1.fire(); m2.fire(); m3.fire(); So effectively the above solutions give us "true" constructors that accept variable no. of arguments and don't require new. What's your take on this. -- UPDATE -- Some have said "just throw an error". My response is: we are doing a heavy app with 10+ constructors and I think it'd be far more wieldy if every constructor could "smartly" handle that mistake without throwing error messages on the console.

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  • Code style Tip: Case insensitive string comparison

    - by Michael Freidgeim
    Goodif (String.Compare(myString, ALL_TEXT, StringComparison.OrdinalIgnoreCase) == 0)                                {                                         return true;                                }OK(not obvious what true means) if (String.Compare(myString, ALL_TEXT, true) == 0)                                {                                         return true;                                }BAD: (non null safe) if (myString.ToLower()==ALL_TEXT.ToLower()                                {                                         return true;                                }

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  • How to create a simple adf dashboard application with EJB 3.0

    - by Rodrigues, Raphael
    In this month's Oracle Magazine, Frank Nimphius wrote a very good article about an Oracle ADF Faces dashboard application to support persistent user personalization. You can read this entire article clicking here. The idea in this article is to extend the dashboard application. My idea here is to create a similar dashboard application, but instead ADF BC model layer, I'm intending to use EJB3.0. There are just a one small trick here and I'll show you. I'm using the HR usual oracle schema. The steps are: 1. Create a ADF Fusion Application with EJB as a layer model 2. Generate the entities from table (I'm using Department and Employees only) 3. Create a new Session Bean. I called it: HRSessionEJB 4. Create a new method like that: public List getAllDepartmentsHavingEmployees(){ JpaEntityManager jpaEntityManager = (JpaEntityManager)em.getDelegate(); Query query = jpaEntityManager.createNamedQuery("Departments.allDepartmentsHavingEmployees"); JavaBeanResult.setQueryResultClass(query, AggregatedDepartment.class); return query.getResultList(); } 5. In the Departments entity, create a new native query annotation: @Entity @NamedQueries( { @NamedQuery(name = "Departments.findAll", query = "select o from Departments o") }) @NamedNativeQueries({ @NamedNativeQuery(name="Departments.allDepartmentsHavingEmployees", query = "select e.department_id, d.department_name , sum(e.salary), avg(e.salary) , max(e.salary), min(e.salary) from departments d , employees e where d.department_id = e.department_id group by e.department_id, d.department_name")}) public class Departments implements Serializable {...} 6. Create a new POJO called AggregatedDepartment: package oramag.sample.dashboard.model; import java.io.Serializable; import java.math.BigDecimal; public class AggregatedDepartment implements Serializable{ @SuppressWarnings("compatibility:5167698678781240729") private static final long serialVersionUID = 1L; private BigDecimal departmentId; private String departmentName; private BigDecimal sum; private BigDecimal avg; private BigDecimal max; private BigDecimal min; public AggregatedDepartment() { super(); } public AggregatedDepartment(BigDecimal departmentId, String departmentName, BigDecimal sum, BigDecimal avg, BigDecimal max, BigDecimal min) { super(); this.departmentId = departmentId; this.departmentName = departmentName; this.sum = sum; this.avg = avg; this.max = max; this.min = min; } public void setDepartmentId(BigDecimal departmentId) { this.departmentId = departmentId; } public BigDecimal getDepartmentId() { return departmentId; } public void setDepartmentName(String departmentName) { this.departmentName = departmentName; } public String getDepartmentName() { return departmentName; } public void setSum(BigDecimal sum) { this.sum = sum; } public BigDecimal getSum() { return sum; } public void setAvg(BigDecimal avg) { this.avg = avg; } public BigDecimal getAvg() { return avg; } public void setMax(BigDecimal max) { this.max = max; } public BigDecimal getMax() { return max; } public void setMin(BigDecimal min) { this.min = min; } public BigDecimal getMin() { return min; } } 7. Create the util java class called JavaBeanResult. The function of this class is to configure a native SQL query to return POJOs in a single line of code using the utility class. Credits: http://onpersistence.blogspot.com.br/2010/07/eclipselink-jpa-native-constructor.html package oramag.sample.dashboard.model.util; /******************************************************************************* * Copyright (c) 2010 Oracle. All rights reserved. * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html * and the Eclipse Distribution License is available at * http://www.eclipse.org/org/documents/edl-v10.php. * * @author shsmith ******************************************************************************/ import java.lang.reflect.Constructor; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.List; import javax.persistence.Query; import org.eclipse.persistence.exceptions.ConversionException; import org.eclipse.persistence.internal.helper.ConversionManager; import org.eclipse.persistence.internal.sessions.AbstractRecord; import org.eclipse.persistence.internal.sessions.AbstractSession; import org.eclipse.persistence.jpa.JpaHelper; import org.eclipse.persistence.queries.DatabaseQuery; import org.eclipse.persistence.queries.QueryRedirector; import org.eclipse.persistence.sessions.Record; import org.eclipse.persistence.sessions.Session; /*** * This class is a simple query redirector that intercepts the result of a * native query and builds an instance of the specified JavaBean class from each * result row. The order of the selected columns musts match the JavaBean class * constructor arguments order. * * To configure a JavaBeanResult on a native SQL query use: * JavaBeanResult.setQueryResultClass(query, SomeBeanClass.class); * where query is either a JPA SQL Query or native EclipseLink DatabaseQuery. * * @author shsmith * */ public final class JavaBeanResult implements QueryRedirector { private static final long serialVersionUID = 3025874987115503731L; protected Class resultClass; public static void setQueryResultClass(Query query, Class resultClass) { JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass); DatabaseQuery databaseQuery = JpaHelper.getDatabaseQuery(query); databaseQuery.setRedirector(javaBeanResult); } public static void setQueryResultClass(DatabaseQuery query, Class resultClass) { JavaBeanResult javaBeanResult = new JavaBeanResult(resultClass); query.setRedirector(javaBeanResult); } protected JavaBeanResult(Class resultClass) { this.resultClass = resultClass; } @SuppressWarnings("unchecked") public Object invokeQuery(DatabaseQuery query, Record arguments, Session session) { List results = new ArrayList(); try { Constructor[] constructors = resultClass.getDeclaredConstructors(); Constructor javaBeanClassConstructor = null; // (Constructor) resultClass.getDeclaredConstructors()[0]; Class[] constructorParameterTypes = null; // javaBeanClassConstructor.getParameterTypes(); List rows = (List) query.execute( (AbstractSession) session, (AbstractRecord) arguments); for (Object[] columns : rows) { boolean found = false; for (Constructor constructor : constructors) { javaBeanClassConstructor = constructor; constructorParameterTypes = javaBeanClassConstructor.getParameterTypes(); if (columns.length == constructorParameterTypes.length) { found = true; break; } // if (columns.length != constructorParameterTypes.length) { // throw new ColumnParameterNumberMismatchException( // resultClass); // } } if (!found) throw new ColumnParameterNumberMismatchException( resultClass); Object[] constructorArgs = new Object[constructorParameterTypes.length]; for (int j = 0; j < columns.length; j++) { Object columnValue = columns[j]; Class parameterType = constructorParameterTypes[j]; // convert the column value to the correct type--if possible constructorArgs[j] = ConversionManager.getDefaultManager() .convertObject(columnValue, parameterType); } results.add(javaBeanClassConstructor.newInstance(constructorArgs)); } } catch (ConversionException e) { throw new ColumnParameterMismatchException(e); } catch (IllegalArgumentException e) { throw new ColumnParameterMismatchException(e); } catch (InstantiationException e) { throw new ColumnParameterMismatchException(e); } catch (IllegalAccessException e) { throw new ColumnParameterMismatchException(e); } catch (InvocationTargetException e) { throw new ColumnParameterMismatchException(e); } return results; } public final class ColumnParameterMismatchException extends RuntimeException { private static final long serialVersionUID = 4752000720859502868L; public ColumnParameterMismatchException(Throwable t) { super( "Exception while processing query results-ensure column order matches constructor parameter order", t); } } public final class ColumnParameterNumberMismatchException extends RuntimeException { private static final long serialVersionUID = 1776794744797667755L; public ColumnParameterNumberMismatchException(Class clazz) { super( "Number of selected columns does not match number of constructor arguments for: " + clazz.getName()); } } } 8. Create the DataControl and a jsf or jspx page 9. Drag allDepartmentsHavingEmployees from DataControl and drop in your page 10. Choose Graph > Type: Bar (Normal) > any layout 11. In the wizard screen, Bars label, adds: sum, avg, max, min. In the X Axis label, adds: departmentName, and click in OK button 12. Run the page, the result is showed below: You can download the workspace here . It was using the latest jdeveloper version 11.1.2.2.

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  • BoundingBox created from mesh to origin, making it bigger

    - by Gunnar Södergren
    I'm working on a level-based survival game and I want to design my scenes in Maya and export them as a single model (with multiple meshes) into XNA. My problem is that when I try to create Bounding Boxes(for Collision purposes) for each of the meshes, the are calculated from origin to the far-end of the current mesh, so to speak. I'm thinking that it might have something to do with the position each mesh brings from Maya and that it's interpreted wrongly... or something. Here's the code for when I create the boxes: private static BoundingBox CreateBoundingBox(Model model, ModelMesh mesh) { Matrix[] boneTransforms = new Matrix[model.Bones.Count]; model.CopyAbsoluteBoneTransformsTo(boneTransforms); BoundingBox result = new BoundingBox(); foreach (ModelMeshPart meshPart in mesh.MeshParts) { BoundingBox? meshPartBoundingBox = GetBoundingBox(meshPart, boneTransforms[mesh.ParentBone.Index]); if (meshPartBoundingBox != null) result = BoundingBox.CreateMerged(result, meshPartBoundingBox.Value); } result = new BoundingBox(result.Min, result.Max); return result; } private static BoundingBox? GetBoundingBox(ModelMeshPart meshPart, Matrix transform) { if (meshPart.VertexBuffer == null) return null; Vector3[] positions = VertexElementExtractor.GetVertexElement(meshPart, VertexElementUsage.Position); if (positions == null) return null; Vector3[] transformedPositions = new Vector3[positions.Length]; Vector3.Transform(positions, ref transform, transformedPositions); for (int i = 0; i < transformedPositions.Length; i++) { Console.WriteLine(" " + transformedPositions[i]); } return BoundingBox.CreateFromPoints(transformedPositions); } public static class VertexElementExtractor { public static Vector3[] GetVertexElement(ModelMeshPart meshPart, VertexElementUsage usage) { VertexDeclaration vd = meshPart.VertexBuffer.VertexDeclaration; VertexElement[] elements = vd.GetVertexElements(); Func<VertexElement, bool> elementPredicate = ve => ve.VertexElementUsage == usage && ve.VertexElementFormat == VertexElementFormat.Vector3; if (!elements.Any(elementPredicate)) return null; VertexElement element = elements.First(elementPredicate); Vector3[] vertexData = new Vector3[meshPart.NumVertices]; meshPart.VertexBuffer.GetData((meshPart.VertexOffset * vd.VertexStride) + element.Offset, vertexData, 0, vertexData.Length, vd.VertexStride); return vertexData; } } Here's a link to the picture of the mesh(The model holds six meshes, but I'm only rendering one and it's bounding box to make it clearer: http://www.gsodergren.se/portfolio/wp-content/uploads/2011/10/Screen-shot-2011-10-24-at-1.16.37-AM.png The mesh that I'm refering to is the Cubelike one. The cylinder is a completely different model and not part of any bounding box calculation. I've double- (and tripple-)-checked that this mesh corresponds to this bounding box. Any thoughts on what I'm doing wrong?

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  • String.IsNullOrWhiteSpace

    - by Scott Dorman
    An empty string is different than an unassigned string variable (which is null), and is a string containing no characters between the quotes (""). The .NET Framework provides String.Empty to represent an empty string, and there is no practical difference between ("") and String.Empty. One of the most common string comparisons to perform is to determine if a string variable is equal to an empty string. The fastest and simplest way to determine if a string is empty is to test if the Length property is equal to 0. However, since strings are reference types it is possible for a string variable to be null, which would result in a runtime error when you tried to access the Length property. Since testing to determine if a string is empty is such a common occurrence, the .NET Framework provides the static method String.IsNullOrEmpty method: public static bool IsNullOrEmpty(string value) { if (value != null) { return (value.Length == 0); }   return true; } It is also very common to determine if a string is empty and contains more than just whitespace characters. For example, String.IsNullOrEmpty("   ") would return false, since this string is actually made up of three whitespace characters. In some cases, this may be acceptable, but in many others it is not. TO help simplify testing this scenario, the .NET Framework 4 introduces the String.IsNullOrWhiteSpace method: public static bool IsNullOrWhiteSpace(string value) { if (value != null) { for (int i = 0; i < value.Length; i++) { if (!char.IsWhiteSpace(value[i])) { return false; } } } return true; }   Using either String.IsNullOrEmpty or String.IsNullOrWhiteSpace helps ensure correctness, readability, and consistency, so they should be used in all situations where you need to determine if a string is null, empty, or contains only whitespace characters. Technorati Tags: .NET,C# 4

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  • Salt and hash a password in .NET

    - by Jon Canning
    I endeavoured to follow the CrackStation rules: Salted Password Hashing - Doing it Right    public class SaltedHash     {         public string Hash { get; private set; }         public string Salt { get; private set; }         public SaltedHash(string password)         {             var saltBytes = new byte[32];             new RNGCryptoServiceProvider().GetNonZeroBytes(saltBytes);             Salt = ConvertToBase64String(saltBytes);             var passwordAndSaltBytes = Concat(password, saltBytes);             Hash = ComputeHash(passwordAndSaltBytes);         }         static string ConvertToBase64String(byte[] bytes)         {             return Convert.ToBase64String(bytes);         }         static string ComputeHash(byte[] bytes)         {             return ConvertToBase64String(SHA256.Create().ComputeHash(bytes));         }         static byte[] Concat(string password, byte[] saltBytes)         {             var passwordBytes = Encoding.UTF8.GetBytes(password);             return passwordBytes.Concat(saltBytes).ToArray();         }         public static bool Verify(string salt, string hash, string password)         {             var saltBytes = Convert.FromBase64String(salt);             var passwordAndSaltBytes = Concat(password, saltBytes);             var hashAttempt = ComputeHash(passwordAndSaltBytes);             return hash == hashAttempt;         }     }

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  • Web Application : How to upload multiple images at a time

    - by SAMIR BHOGAYTA
    //First add image control into the web form how many you want to upload images at a time //Add one button //Write the below code into the button_click event if (FileUpload1.HasFile) { string imagefile = FileUpload1.FileName; if (CheckFileType(imagefile) == true) { Random rndob = new Random(); int db = rndob.Next(1, 100); filename = System.IO.Path.GetFileNameWithoutExtension(imagefile) + db.ToString() + System.IO.Path.GetExtension(imagefile); String FilePath = "images/" + filename; FileUpload1.SaveAs(Server.MapPath(FilePath)); objimg.ImageName = filename; Image1(); if (Session["imagecount"].ToString() == "1") { Img1.ImageUrl = FilePath; ViewState["img1"] = FilePath; } else if (Session["imagecount"].ToString() == "2") { Img1.ImageUrl = ViewState["img1"].ToString(); Img2.ImageUrl = FilePath; ViewState["img2"] = FilePath; } else if (Session["imagecount"].ToString() == "3") { Img1.ImageUrl = ViewState["img1"].ToString(); Img2.ImageUrl = ViewState["img2"].ToString(); Img3.ImageUrl = FilePath; ViewState["img3"] = FilePath; } else if (Session["imagecount"].ToString() == "4") { Img1.ImageUrl = ViewState["img1"].ToString(); Img2.ImageUrl = ViewState["img2"].ToString(); Img3.ImageUrl = ViewState["img3"].ToString(); Img4.ImageUrl = FilePath; ViewState["img4"] = FilePath; } else if (Session["imagecount"].ToString() == "5") { Img1.ImageUrl = ViewState["img1"].ToString(); Img2.ImageUrl = ViewState["img2"].ToString(); Img3.ImageUrl = ViewState["img3"].ToString(); Img4.ImageUrl = ViewState["img4"].ToString(); Img5.ImageUrl = FilePath; ViewState["img5"] = FilePath; } } } //execption handling else { lblErrMsg.Visible = true; lblErrMsg.Text = ""; lblErrMsg.Text = "please select a file"; } } //if file extension belongs to these list then only allowed public bool CheckFileType(string filename) { string ext; ext = System.IO.Path.GetExtension(filename); switch (ext.ToLower()) { case ".gif": return true; case ".jpeg": return true; case ".jpg": return true; case ".bmp": return true; case ".png": return true; default: return false; } }

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  • C#: LINQ vs foreach - Round 1.

    - by James Michael Hare
    So I was reading Peter Kellner's blog entry on Resharper 5.0 and its LINQ refactoring and thought that was very cool.  But that raised a point I had always been curious about in my head -- which is a better choice: manual foreach loops or LINQ?    The answer is not really clear-cut.  There are two sides to any code cost arguments: performance and maintainability.  The first of these is obvious and quantifiable.  Given any two pieces of code that perform the same function, you can run them side-by-side and see which piece of code performs better.   Unfortunately, this is not always a good measure.  Well written assembly language outperforms well written C++ code, but you lose a lot in maintainability which creates a big techncial debt load that is hard to offset as the application ages.  In contrast, higher level constructs make the code more brief and easier to understand, hence reducing technical cost.   Now, obviously in this case we're not talking two separate languages, we're comparing doing something manually in the language versus using a higher-order set of IEnumerable extensions that are in the System.Linq library.   Well, before we discuss any further, let's look at some sample code and the numbers.  First, let's take a look at the for loop and the LINQ expression.  This is just a simple find comparison:       // find implemented via LINQ     public static bool FindViaLinq(IEnumerable<int> list, int target)     {         return list.Any(item => item == target);     }         // find implemented via standard iteration     public static bool FindViaIteration(IEnumerable<int> list, int target)     {         foreach (var i in list)         {             if (i == target)             {                 return true;             }         }           return false;     }   Okay, looking at this from a maintainability point of view, the Linq expression is definitely more concise (8 lines down to 1) and is very readable in intention.  You don't have to actually analyze the behavior of the loop to determine what it's doing.   So let's take a look at performance metrics from 100,000 iterations of these methods on a List<int> of varying sizes filled with random data.  For this test, we fill a target array with 100,000 random integers and then run the exact same pseudo-random targets through both searches.                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     Any         10       26          0.00046             30.00%     Iteration   10       20          0.00023             -     Any         100      116         0.00201             18.37%     Iteration   100      98          0.00118             -     Any         1000     1058        0.01853             16.78%     Iteration   1000     906         0.01155             -     Any         10,000   10,383      0.18189             17.41%     Iteration   10,000   8843        0.11362             -     Any         100,000  104,004     1.8297              18.27%     Iteration   100,000  87,941      1.13163             -   The LINQ expression is running about 17% slower for average size collections and worse for smaller collections.  Presumably, this is due to the overhead of the state machine used to track the iterators for the yield returns in the LINQ expressions, which seems about right in a tight loop such as this.   So what about other LINQ expressions?  After all, Any() is one of the more trivial ones.  I decided to try the TakeWhile() algorithm using a Count() to get the position stopped like the sample Pete was using in his blog that Resharper refactored for him into LINQ:       // Linq form     public static int GetTargetPosition1(IEnumerable<int> list, int target)     {         return list.TakeWhile(item => item != target).Count();     }       // traditionally iterative form     public static int GetTargetPosition2(IEnumerable<int> list, int target)     {         int count = 0;           foreach (var i in list)         {             if(i == target)             {                 break;             }               ++count;         }           return count;     }   Once again, the LINQ expression is much shorter, easier to read, and should be easier to maintain over time, reducing the cost of technical debt.  So I ran these through the same test data:                       List<T> On 100,000 Iterations     Method      Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile   10       41          0.00041             128%     Iteration   10       18          0.00018             -     TakeWhile   100      171         0.00171             88%     Iteration   100      91          0.00091             -     TakeWhile   1000     1604        0.01604             94%     Iteration   1000     825         0.00825             -     TakeWhile   10,000   15765       0.15765             92%     Iteration   10,000   8204        0.08204             -     TakeWhile   100,000  156950      1.5695              92%     Iteration   100,000  81635       0.81635             -     Wow!  I expected some overhead due to the state machines iterators produce, but 90% slower?  That seems a little heavy to me.  So then I thought, well, what if TakeWhile() is not the right tool for the job?  The problem is TakeWhile returns each item for processing using yield return, whereas our for-loop really doesn't care about the item beyond using it as a stop condition to evaluate. So what if that back and forth with the iterator state machine is the problem?  Well, we can quickly create an (albeit ugly) lambda that uses the Any() along with a count in a closure (if a LINQ guru knows a better way PLEASE let me know!), after all , this is more consistent with what we're trying to do, we're trying to find the first occurence of an item and halt once we find it, we just happen to be counting on the way.  This mostly matches Any().       // a new method that uses linq but evaluates the count in a closure.     public static int TakeWhileViaLinq2(IEnumerable<int> list, int target)     {         int count = 0;         list.Any(item =>             {                 if(item == target)                 {                     return true;                 }                   ++count;                 return false;             });         return count;     }     Now how does this one compare?                         List<T> On 100,000 Iterations     Method         Size     Total (ms)  Per Iteration (ms)  % Slower     TakeWhile      10       41          0.00041             128%     Any w/Closure  10       23          0.00023             28%     Iteration      10       18          0.00018             -     TakeWhile      100      171         0.00171             88%     Any w/Closure  100      116         0.00116             27%     Iteration      100      91          0.00091             -     TakeWhile      1000     1604        0.01604             94%     Any w/Closure  1000     1101        0.01101             33%     Iteration      1000     825         0.00825             -     TakeWhile      10,000   15765       0.15765             92%     Any w/Closure  10,000   10802       0.10802             32%     Iteration      10,000   8204        0.08204             -     TakeWhile      100,000  156950      1.5695              92%     Any w/Closure  100,000  108378      1.08378             33%     Iteration      100,000  81635       0.81635             -     Much better!  It seems that the overhead of TakeAny() returning each item and updating the state in the state machine is drastically reduced by using Any() since Any() iterates forward until it finds the value we're looking for -- for the task we're attempting to do.   So the lesson there is, make sure when you use a LINQ expression you're choosing the best expression for the job, because if you're doing more work than you really need, you'll have a slower algorithm.  But this is true of any choice of algorithm or collection in general.     Even with the Any() with the count in the closure it is still about 30% slower, but let's consider that angle carefully.  For a list of 100,000 items, it was the difference between 1.01 ms and 0.82 ms roughly in a List<T>.  That's really not that bad at all in the grand scheme of things.  Even running at 90% slower with TakeWhile(), for the vast majority of my projects, an extra millisecond to save potential errors in the long term and improve maintainability is a small price to pay.  And if your typical list is 1000 items or less we're talking only microseconds worth of difference.   It's like they say: 90% of your performance bottlenecks are in 2% of your code, so over-optimizing almost never pays off.  So personally, I'll take the LINQ expression wherever I can because they will be easier to read and maintain (thus reducing technical debt) and I can rely on Microsoft's development to have coded and unit tested those algorithm fully for me instead of relying on a developer to code the loop logic correctly.   If something's 90% slower, yes, it's worth keeping in mind, but it's really not until you start get magnitudes-of-order slower (10x, 100x, 1000x) that alarm bells should really go off.  And if I ever do need that last millisecond of performance?  Well then I'll optimize JUST THAT problem spot.  To me it's worth it for the readability, speed-to-market, and maintainability.

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  • XNA 3D model collision is inaccurate

    - by Daniel Lopez
    I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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  • Achieve Named Criteria with multiple tables in EJB Data control

    - by Deepak Siddappa
    In EJB create a named criteria using sparse xml and in named criteria wizard, only attributes related to the that particular entities will be displayed.  So here we can filter results only on particular entity bean. Take a scenario where we need to create Named Criteria based on multiple tables using EJB. In BC4J we can achieve this by creating view object based on multiple tables. So in this article, we will try to achieve named criteria based on multiple tables using EJB.Implementation StepsCreate Java EE Web Application with entity based on Departments and Employees, then create a session bean and data control for the session bean.Create a Java Bean, name as CustomBean and add below code to the file. Here in java bean from both Departments and Employees tables three fields are taken. public class CustomBean { private BigDecimal departmentId; private String departmentName; private BigDecimal locationId; private BigDecimal employeeId; private String firstName; private String lastName; public CustomBean() { super(); } public void setDepartmentId(BigDecimal departmentId) { this.departmentId = departmentId; } public BigDecimal getDepartmentId() { return departmentId; } public void setDepartmentName(String departmentName) { this.departmentName = departmentName; } public String getDepartmentName() { return departmentName; } public void setLocationId(BigDecimal locationId) { this.locationId = locationId; } public BigDecimal getLocationId() { return locationId; } public void setEmployeeId(BigDecimal employeeId) { this.employeeId = employeeId; } public BigDecimal getEmployeeId() { return employeeId; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getFirstName() { return firstName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getLastName() { return lastName; } } Open the sessionEJb file and add the below code to the session bean and expose the method in local/remote interface and generate a data control for that. Note:- Here in the below code "em" is a EntityManager. public List<CustomBean> getCustomBeanFindAll() { String queryString = "select d.department_id, d.department_name, d.location_id, e.employee_id, e.first_name, e.last_name from departments d, employees e\n" + "where e.department_id = d.department_id"; Query genericSearchQuery = em.createNativeQuery(queryString, "CustomQuery"); List resultList = genericSearchQuery.getResultList(); Iterator resultListIterator = resultList.iterator(); List<CustomBean> customList = new ArrayList(); while (resultListIterator.hasNext()) { Object col[] = (Object[])resultListIterator.next(); CustomBean custom = new CustomBean(); custom.setDepartmentId((BigDecimal)col[0]); custom.setDepartmentName((String)col[1]); custom.setLocationId((BigDecimal)col[2]); custom.setEmployeeId((BigDecimal)col[3]); custom.setFirstName((String)col[4]); custom.setLastName((String)col[5]); customList.add(custom); } return customList; } Open the DataControls.dcx file and create sparse xml for customBean. In sparse xml navigate to Named criteria tab -> Bind Variable section, create two binding variables deptId,fName. In sparse xml navigate to Named criteria tab ->Named criteria, create a named criteria and map the query attributes to the bind variables. In the ViewController create a file jspx page, from data control palette drop customBeanFindAll->Named Criteria->CustomBeanCriteria->Query as ADF Query Panel with Table. Run the jspx page and enter values in search form with departmentId as 50 and firstName as "M". Named criteria will filter the query of a data source and display the result like below.

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  • ASP.NET MVC: Moving code from controller action to service layer

    - by DigiMortal
    I fixed one controller action in my application that doesn’t seemed good enough for me. It wasn’t big move I did but worth to show to beginners how nice code you can write when using correct layering in your application. As an example I use code from my posting ASP.NET MVC: How to implement invitation codes support. Problematic controller action Although my controller action works well I don’t like how it looks. It is too much for controller action in my opinion. [HttpPost] public ActionResult GetAccess(string accessCode) {     if(string.IsNullOrEmpty(accessCode.Trim()))     {         ModelState.AddModelError("accessCode", "Insert invitation code!");         return View();     }       Guid accessGuid;       try     {         accessGuid = Guid.Parse(accessCode);     }     catch     {         ModelState.AddModelError("accessCode", "Incorrect format of invitation code!");         return View();                    }       using(var ctx = new EventsEntities())     {         var user = ctx.GetNewUserByAccessCode(accessGuid);         if(user == null)         {             ModelState.AddModelError("accessCode", "Cannot find account with given invitation code!");             return View();         }           user.UserToken = User.Identity.GetUserToken();         ctx.SaveChanges();     }       Session["UserId"] = accessGuid;       return Redirect("~/admin"); } Looking at this code my first idea is that all this access code stuff must be located somewhere else. We have working functionality in wrong place and we should do something about it. Service layer I add layers to my application very carefully because I don’t like to use hand grenade to kill a fly. When I see real need for some layer and it doesn’t add too much complexity I will add new layer. Right now it is good time to add service layer to my small application. After that it is time to move code to service layer and inject service class to controller. public interface IUserService {     bool ClaimAccessCode(string accessCode, string userToken,                          out string errorMessage);       // Other methods of user service } I need this interface when writing unit tests because I need fake service that doesn’t communicate with database and other external sources. public class UserService : IUserService {     private readonly IDataContext _context;       public UserService(IDataContext context)     {         _context = context;     }       public bool ClaimAccessCode(string accessCode, string userToken, out string errorMessage)     {         if (string.IsNullOrEmpty(accessCode.Trim()))         {             errorMessage = "Insert invitation code!";             return false;         }           Guid accessGuid;         if (!Guid.TryParse(accessCode, out accessGuid))         {             errorMessage = "Incorrect format of invitation code!";             return false;         }           var user = _context.GetNewUserByAccessCode(accessGuid);         if (user == null)         {             errorMessage = "Cannot find account with given invitation code!";             return false;         }           user.UserToken = userToken;         _context.SaveChanges();           errorMessage = string.Empty;         return true;     } } Right now I used simple solution for errors and made access code claiming method to follow usual TrySomething() methods pattern. This way I can keep error messages and their retrieval away from controller and in controller I just mediate error message from service to view. Controller Now all the code is moved to service layer and we need also some modifications to controller code so it makes use of users service. I don’t show here DI/IoC details about how to give service instance to controller. GetAccess() action of controller looks like this right now. [HttpPost] public ActionResult GetAccess(string accessCode) {     var userToken = User.Identity.GetUserToken();     string errorMessage;       if (!_userService.ClaimAccessCode(accessCode, userToken,                                       out errorMessage))     {                       ModelState.AddModelError("accessCode", errorMessage);         return View();     }       Session["UserId"] = Guid.Parse(accessCode);     return Redirect("~/admin"); } It’s short and nice now and it deals with web site part of access code claiming. In the case of error user is shown access code claiming view with error message that ClaimAccessCode() method returns as output parameter. If everything goes fine then access code is reserved for current user and user is authenticated. Conclusion When controller action grows big you have to move code to layers it actually belongs. In this posting I showed you how I moved access code claiming functionality from controller action to user service class that belongs to service layer of my application. As the result I have controller action that coordinates the user interaction when going through access code claiming process. Controller communicates with service layer and gets information about how access code claiming succeeded.

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  • Functional Methods on Collections

    - by GlenPeterson
    I'm learning Scala and am a little bewildered by all the methods (higher-order functions) available on the collections. Which ones produce more results than the original collection, which ones produce less, and which are most appropriate for a given problem? Though I'm studying Scala, I think this would pertain to most modern functional languages (Clojure, Haskell) and also to Java 8 which introduces these methods on Java collections. Specifically, right now I'm wondering about map with filter vs. fold/reduce. I was delighted that using foldRight() can yield the same result as a map(...).filter(...) with only one traversal of the underlying collection. But a friend pointed out that foldRight() may force sequential processing while map() is friendlier to being processed by multiple processors in parallel. Maybe this is why mapReduce() is so popular? More generally, I'm still sometimes surprised when I chain several of these methods together to get back a List(List()) or to pass a List(List()) and get back just a List(). For instance, when would I use: collection.map(a => a.map(b => ...)) vs. collection.map(a => ...).map(b => ...) The for/yield command does nothing to help this confusion. Am I asking about the difference between a "fold" and "unfold" operation? Am I trying to jam too many questions into one? I think there may be an underlying concept that, if I understood it, might answer all these questions, or at least tie the answers together.

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  • Java collision detection and player movement: tips

    - by Loris
    I have read a short guide for game develompent (java, without external libraries). I'm facing with collision detection and player (and bullets) movements. Now i put the code. Most of it is taken from the guide (should i link this guide?). I'm just trying to expand and complete it. This is the class that take care of updates movements and firing mechanism (and collision detection): public class ArenaController { private Arena arena; /** selected cell for movement */ private float targetX, targetY; /** true if droid is moving */ private boolean moving = false; /** true if droid is shooting to enemy */ private boolean shooting = false; private DroidController droidController; public ArenaController(Arena arena) { this.arena = arena; this.droidController = new DroidController(arena); } public void update(float delta) { Droid droid = arena.getDroid(); //droid movements if (moving) { droidController.moveDroid(delta, targetX, targetY); //check if arrived if (droid.getX() == targetX && droid.getY() == targetY) moving = false; } //firing mechanism if(shooting) { //stop shot if there aren't bullets if(arena.getBullets().isEmpty()) { shooting = false; } for(int i = 0; i < arena.getBullets().size(); i++) { //current bullet Bullet bullet = arena.getBullets().get(i); System.out.println(bullet.getBounds()); //angle calculation double angle = Math.atan2(bullet.getEnemyY() - bullet.getY(), bullet.getEnemyX() - bullet.getX()); //increments x and y bullet.setX((float) (bullet.getX() + (Math.cos(angle) * bullet.getSpeed() * delta))); bullet.setY((float) (bullet.getY() + (Math.sin(angle) * bullet.getSpeed() * delta))); //collision with obstacles for(int j = 0; j < arena.getObstacles().size(); j++) { Obstacle obs = arena.getObstacles().get(j); if(bullet.getBounds().intersects(obs.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } //collisions with enemies for(int j = 0; j < arena.getEnemies().size(); j++) { Enemy ene = arena.getEnemies().get(j); if(bullet.getBounds().intersects(ene.getBounds())) { System.out.println("Collision detect!"); arena.removeBullet(bullet); } } } } } public boolean onClick(int x, int y) { //click on empty cell if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] == null) { //coordinates targetX = x / Arena.TILE; targetY = y / Arena.TILE; //enables movement moving = true; return true; } //click on enemy: fire if(arena.getGrid()[(int)(y / Arena.TILE)][(int)(x / Arena.TILE)] instanceof Enemy) { //coordinates float enemyX = x / Arena.TILE; float enemyY = y / Arena.TILE; //new bullet Bullet bullet = new Bullet(); //start coordinates bullet.setX(arena.getDroid().getX()); bullet.setY(arena.getDroid().getY()); //end coordinates (enemie) bullet.setEnemyX(enemyX); bullet.setEnemyY(enemyY); //adds bullet to arena arena.addBullet(bullet); //enables shooting shooting = true; return true; } return false; } As you can see for collision detection i'm trying to use Rectangle object. Droid example: import java.awt.geom.Rectangle2D; public class Droid { private float x; private float y; private float speed = 20f; private float rotation = 0f; private float damage = 2f; public static final int DIAMETER = 32; private Rectangle2D rectangle; public Droid() { rectangle = new Rectangle2D.Float(x, y, DIAMETER, DIAMETER); } public float getX() { return x; } public void setX(float x) { this.x = x; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getY() { return y; } public void setY(float y) { this.y = y; //rectangle update rectangle.setRect(x, y, DIAMETER, DIAMETER); } public float getSpeed() { return speed; } public void setSpeed(float speed) { this.speed = speed; } public float getRotation() { return rotation; } public void setRotation(float rotation) { this.rotation = rotation; } public float getDamage() { return damage; } public void setDamage(float damage) { this.damage = damage; } public Rectangle2D getRectangle() { return rectangle; } } For now, if i start the application and i try to shot to an enemy, is immediately detected a collision and the bullet is removed! Can you help me with this? If the bullet hit an enemy or an obstacle in his way, it must disappear. Ps: i know that the movements of the bullets should be managed in another class. This code is temporary. update I realized what happens, but not why. With those for loops (which checks collisions) the movements of the bullets are instantaneous instead of gradual. In addition to this, if i add the collision detection to the Droid, the method intersects returns true ALWAYS while the droid is moving! public void moveDroid(float delta, float x, float y) { Droid droid = arena.getDroid(); int bearing = 1; if (droid.getX() > x) { bearing = -1; } if (droid.getX() != x) { droid.setX(droid.getX() + bearing * droid.getSpeed() * delta); //obstacles collision detection for(Obstacle obs : arena.getObstacles()) { if(obs.getRectangle().intersects(droid.getRectangle())) { System.out.println("Collision detected"); //ALWAYS HERE } } //controlla se è arrivato if ((droid.getX() < x && bearing == -1) || (droid.getX() > x && bearing == 1)) droid.setX(x); } bearing = 1; if (droid.getY() > y) { bearing = -1; } if (droid.getY() != y) { droid.setY(droid.getY() + bearing * droid.getSpeed() * delta); if ((droid.getY() < y && bearing == -1) || (droid.getY() > y && bearing == 1)) droid.setY(y); } }

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  • Why does void in C mean not void?

    - by Naftuli Tzvi Kay
    In strongly-typed languages like Java and C#, void (or Void) as a return type for a method seem to mean: This method doesn't return anything. Nothing. No return. You will not receive anything from this method. What's really strange is that in C, void as a return type or even as a method parameter type means: It could really be anything. You'd have to read the source code to find out. Good luck. If it's a pointer, you should really know what you're doing. Consider the following examples in C: void describe(void *thing) { Object *obj = thing; printf("%s.\n", obj->description); } void *move(void *location, Direction direction) { void *next = NULL; // logic! return next; } Obviously, the second method returns a pointer, which by definition could be anything. Since C is older than Java and C#, why did these languages adopt void as meaning "nothing" while C used it as "nothing or anything (when a pointer)"?

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  • Can't I just use all static methods?

    - by Reddy S R
    What's the difference between the two UpdateSubject methods below? I felt using static methods is better if you just want to operate on the entities. In which situations should I go with non-static methods? public class Subject { public int Id {get; set;} public string Name { get; set; } public static bool UpdateSubject(Subject subject) { //Do something and return result return true; } public bool UpdateSubject() { //Do something on 'this' and return result return true; } } I know I will be getting many kicks from the community for this really annoying question but I could not stop myself asking it. Does this become impractical when dealing with inheritance?

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  • SQL SERVER – Introduction to Function SIGN

    - by pinaldave
    Yesterday I received an email from a friend asking how do SIGN function works. Well SIGN Function is very fundamental function. It will return the value 1, -1 or 0. If your value is negative it will return you negative -1 and if it is positive it will return you positive +1. Let us start with a simple small example. DECLARE @IntVal1 INT, @IntVal2 INT,@IntVal3 INT DECLARE @NumVal1 DECIMAL(4,2), @NumVal2 DECIMAL(4,2),@NumVal3 DECIMAL(4,2) SET @IntVal1 = 9; SET @IntVal2 = -9; SET @IntVal3 = 0; SET @NumVal1 = 9.0; SET @NumVal2 = -9.0; SET @NumVal3 = 0.0; SELECT SIGN(@IntVal1) IntVal1,SIGN(@IntVal2) IntVal2,SIGN(@IntVal3) IntVal3 SELECT SIGN(@NumVal1) NumVal1,SIGN(@NumVal2) NumVal2,SIGN(@NumVal2) NumVal3   The above function will give us following result set. You will notice that when there is positive value the function gives positive values and if the values are negative it will return you negative values. Also you will notice that if the data type is  INT the return value is INT and when the value passed to the function is Numeric the result also matches it. Not every datatype is compatible with this function.  Here is the quick look up of the return types. bigint -> bigint int/smallint/tinyint -> int money/smallmoney -> money numeric/decimal -> numeric/decimal everybody else -> float What will be the best example of the usage of this function that you will not have to use the CASE Statement. Here is example of CASE Statement usage and the same replaced with SIGN function. USE tempdb GO CREATE TABLE TestTable (Date1 SMALLDATETIME, Date2 SMALLDATETIME) INSERT INTO TestTable (Date1, Date2) SELECT '2012-06-22 16:15', '2012-06-20 16:15' UNION ALL SELECT '2012-06-24 16:15', '2012-06-22 16:15' UNION ALL SELECT '2012-06-22 16:15', '2012-06-22 16:15' GO -- Using Case Statement SELECT CASE WHEN DATEDIFF(d,Date1,Date2) > 0 THEN 1 WHEN DATEDIFF(d,Date1,Date2) < 0 THEN -1 ELSE 0 END AS Col FROM TestTable GO -- Using SIGN Function SELECT SIGN(DATEDIFF(d,Date1,Date2)) AS Col FROM TestTable GO DROP TABLE TestTable GO This was interesting blog post for me to write. Let me know your opinion. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • How to build a Singleton-like dependency injector replacement (Php)

    - by Erparom
    I know out there are a lot of excelent containers, even frameworks almost entirely DI based with good strong IoC classes. However, this doesn't help me to "define" a new pattern. (This is Php code but understandable to anyone) Supose we have: //Declares the singleton class bookSingleton { private $author; private static $bookInstance; private static $isLoaned = FALSE; //The private constructor private function __constructor() { $this->author = "Onecrappy Writer Ofcheap Novels"; } //Sets the global isLoaned state and also gets self instance public static function loanBook() { if (self::$isLoaned === FALSE) { //Book already taken, so return false return FALSE; } else { //Ok, not loaned, lets instantiate (if needed and loan) if (!isset(self::$bookInstance)) { self::$bookInstance = new BookSingleton(); } self::$isLoaned = TRUE; } } //Return loaned state to false, so another book reader can take the book public function returnBook() { $self::$isLoaned = FALSE; } public function getAuthor() { return $this->author; } } Then we get the singelton consumtion class: //Consumes the Singleton class BookBorrower() { private $borrowedBook; private $haveBookState; public function __construct() { this->haveBookState = FALSE; } //Use the singelton-pattern behavior public function borrowBook() { $this->borrowedBook = BookSingleton::loanBook(); //Check if was successfully borrowed if (!this->borrowedBook) { $this->haveBookState = FALSE; } else { $this->haveBookState = TRUE; } } public function returnBook() { $this->borrowedBook->returnBook(); $this->haveBookState = FALSE; } public function getBook() { if ($this->haveBookState) { return "The book is loaned, the author is" . $this->borrowedbook->getAuthor(); } else { return "I don't have the book, perhaps someone else took it"; } } } At last, we got a client, to test the behavior function __autoload($class) { require_once $class . '.php'; } function write ($whatever,$breaks) { for($break = 0;$break<$breaks;$break++) { $whatever .= "\n"; } echo nl2br($whatever); } write("Begin Singleton test", 2); $borrowerJuan = new BookBorrower(); $borrowerPedro = new BookBorrower(); write("Juan asks for the book", 1); $borrowerJuan->borrowBook(); write("Book Borrowed? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); write("Juan returns the book", 1); $borrowerJuan->returnBook(); write("Returned Book Juan? ", 1); write($borrowerJuan->getAuthorAndTitle(),2); write("Pedro asks again for the book", 1); $borrowerPedro->borrowBook(); write("Book Borrowed? ", 1); write($borrowerPedro->getAuthorAndTitle(),2); This will end up in the expected behavior: Begin Singleton test Juan asks for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels Pedro asks for the book Book Borrowed? I don't have the book, perhaps someone else took it Juan returns the book Returned Book Juan? I don't have the book, perhaps someone else took it Pedro asks again for the book Book Borrowed? The book is loaned, the author is = Onecrappy Writer Ofcheap Novels So I want to make a pattern based on the DI technique able to do exactly the same, but without singleton pattern. As far as I'm aware, I KNOW I must inject the book inside "borrowBook" function instead of taking a static instance: public function borrowBook(BookNonSingleton $book) { if (isset($this->borrowedBook) || $book->isLoaned()) { $this->haveBook = FALSE; return FALSE; } else { $this->borrowedBook = $book; $this->haveBook = TRUE; return TRUE; } } And at the client, just handle the book: $borrowerJuan = new BookBorrower(); $borrowerJuan-borrowBook(new NonSingletonBook()); Etc... and so far so good, BUT... Im taking the responsability of "single instance" to the borrower, instead of keeping that responsability inside the NonSingletonBook, that since it has not anymore a private constructor, can be instantiated as many times... making instances on each call. So, What does my NonSingletonBook class MUST be in order to never allow borrowers to have this same book twice? (aka) keep the single instance. Because the dependency injector part of the code (borrower) does not solve me this AT ALL. Is it needed the container with an "asShared" method builder with static behavior? No way to encapsulate this functionallity into the Book itself? "Hey Im a book and I shouldn't be instantiated more than once, I'm unique"

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  • C++ 'using': Should I use it or should I avoid it?

    - by Mehrdad
    I realize there are subtly different semantics for some of these, because of ADL. In general, though: Which one should I prefer (if any), and why? (Or does it depend on the situation (e.g. inline header vs. implementation?) Also: should I prefer ::std:: over std::? using namespace std; pair<string::const_iterator, string::const_iterator> f(const string &s) { return make_pair(s.begin(), s.end()); } or std::pair<std::string::const_iterator, std::string::const_iterator> f(const std::string &s) { return std::make_pair(s.begin(), s.end()); } or using std::pair; using std::string; pair<string::const_iterator, string::const_iterator> f(const string &s) { return make_pair(s.begin(), s.end()); } or std::pair<std::string::const_iterator, std::string::const_iterator> f(const std::string &s) { using std::make_pair; return make_pair(s.begin(), s.end()); } or std::pair<std::string::const_iterator, std::string::const_iterator> f(const std::string &s) { using namespace std; return make_pair(s.begin(), s.end()); } or something else? (This is assuming I don't have C++11 and auto.)

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  • Which of these design patterns is superior?

    - by durron597
    I find I tend to design class structures where several subclasses have nearly identical functionality, but one piece of it is different. So I write nearly all the code in the abstract class, and then create several subclasses to do the one different thing. Does this pattern have a name? Is this the best way for this sort of scenario? Option 1: public interface TaxCalc { String calcTaxes(); } public abstract class AbstractTaxCalc implements TaxCalc { // most constructors and fields are here public double calcTaxes(UserFinancials data) { // code double diffNumber = getNumber(data); // more code } abstract protected double getNumber(UserFinancials data); protected double initialTaxes(double grossIncome) { // code return initialNumber; } } public class SimpleTaxCalc extends AbstractCalc { protected double getNumber(UserFinancials data) { double temp = intialCalc(data.getGrossIncome()); // do other stuff return temp; } } public class FancyTaxCalc extends AbstractTaxCalc { protected double getNumber(UserFinancials data) { int temp = initialCalc(data.getGrossIncome()); // Do fancier math return temp; } } Option 2: This version is more like the Strategy pattern, and should be able to do essentially the same sorts of tasks. public class TaxCalcImpl implements TaxCalc { private final TaxMath worker; public DummyImpl(TaxMath worker) { this.worker = worker; } public double calcTaxes(UserFinancials data) { // code double analyzedDouble = initialNumber; int diffNumber = worker.getNumber(data, initialNumber); // more code } protected int initialTaxes(double grossIncome) { // code return initialNumber; } } public interface TaxMath { double getNumber(UserFinancials data, double initial); } Then I could do: TaxCalc dum = new TaxCalcImpl(new TaxMath() { @Override public double getNumber(UserFinancials data, double initial) { double temp = data.getGrossIncome(); // do math return temp; }); And I could make specific implementations of TaxMath for things I use a lot, or I could make a stateless singleton for certain kinds of workers I use a lot. So the question I'm asking is: Which of these patterns is superior, when, and why? Or, alternately, is there an even better third option?

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  • An Unusual UpdatePanel

    - by João Angelo
    The code you are about to see was mostly to prove a point, to myself, and probably has limited applicability. Nonetheless, in the remote possibility this is useful to someone here it goes… So this is a control that acts like a normal UpdatePanel where all child controls are registered as postback triggers except for a single control specified by the TriggerControlID property. You could basically achieve the same thing by registering all controls as postback triggers in the regular UpdatePanel. However with this, that process is performed automatically. Finally, here is the code: public sealed class SingleAsyncTriggerUpdatePanel : WebControl, INamingContainer { public string TriggerControlID { get; set; } [TemplateInstance(TemplateInstance.Single)] [PersistenceMode(PersistenceMode.InnerProperty)] public ITemplate ContentTemplate { get; set; } public override ControlCollection Controls { get { this.EnsureChildControls(); return base.Controls; } } protected override void CreateChildControls() { if (string.IsNullOrWhiteSpace(this.TriggerControlID)) throw new InvalidOperationException( "The TriggerControlId property must be set."); this.Controls.Clear(); var updatePanel = new UpdatePanel() { ID = string.Concat(this.ID, "InnerUpdatePanel"), ChildrenAsTriggers = false, UpdateMode = UpdatePanelUpdateMode.Conditional, ContentTemplate = this.ContentTemplate }; updatePanel.Triggers.Add(new SingleControlAsyncUpdatePanelTrigger { ControlID = this.TriggerControlID }); this.Controls.Add(updatePanel); } } internal sealed class SingleControlAsyncUpdatePanelTrigger : UpdatePanelControlTrigger { private Control target; private ScriptManager scriptManager; public Control Target { get { if (this.target == null) { this.target = this.FindTargetControl(true); } return this.target; } } public ScriptManager ScriptManager { get { if (this.scriptManager == null) { var page = base.Owner.Page; if (page != null) { this.scriptManager = ScriptManager.GetCurrent(page); } } return this.scriptManager; } } protected override bool HasTriggered() { string asyncPostBackSourceElementID = this.ScriptManager.AsyncPostBackSourceElementID; if (asyncPostBackSourceElementID == this.Target.UniqueID) return true; return asyncPostBackSourceElementID.StartsWith( string.Concat(this.target.UniqueID, "$"), StringComparison.Ordinal); } protected override void Initialize() { base.Initialize(); foreach (Control control in FlattenControlHierarchy(this.Owner.Controls)) { if (control == this.Target) continue; bool isApplicableControl = false; isApplicableControl |= control is INamingContainer; isApplicableControl |= control is IPostBackDataHandler; isApplicableControl |= control is IPostBackEventHandler; if (isApplicableControl) { this.ScriptManager.RegisterPostBackControl(control); } } } private static IEnumerable<Control> FlattenControlHierarchy( ControlCollection collection) { foreach (Control control in collection) { yield return control; if (control.Controls.Count > 0) { foreach (Control child in FlattenControlHierarchy(control.Controls)) { yield return child; } } } } } You can use it like this, meaning that only the B2 button will trigger an async postback: <cc:SingleAsyncTriggerUpdatePanel ID="Test" runat="server" TriggerControlID="B2"> <ContentTemplate> <asp:Button ID="B1" Text="B1" runat="server" OnClick="Button_Click" /> <asp:Button ID="B2" Text="B2" runat="server" OnClick="Button_Click" /> <asp:Button ID="B3" Text="B3" runat="server" OnClick="Button_Click" /> <asp:Label ID="LInner" Text="LInner" runat="server" /> </ContentTemplate> </cc:SingleAsyncTriggerUpdatePanel>

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  • Sorting and Filtering By Model-Based LOV Display Value

    - by Steven Davelaar
    If you use a model-based LOV and you use display type "choice", then ADF nicely displays the display value, even if the table is read-only. In the screen shot below, you see the RegionName attribute displayed instead of the RegionId. This is accomplished by the model-based LOV, I did not modify the Countries view object to include a join with Regions.  Also note the sort icon, the table is sorted by RegionId. This sorting typically results in a bug reported by your test team. Europe really shouldn't come before America when sorting ascending, right? To fix this, we could of course change the Countries view object query and add a join with the Regions table to include the RegionName attribute. If the table is updateable, we still need the choice list, so we need to move the model-based LOV from the RegionId attribute to the RegionName attribute and hide the RegionId attribute in the table. But that is a lot of work for such a simple requirement, in particular if we have lots of model-based choice lists in our view object. Fortunately, there is an easier way to do this, with some generic code in your view object base class that fixes this at once for all model-based choice lists that we have defined in our application. The trick is to override the method getSortCriteria() in the base view object class. By default, this method returns null because the sorting is done in the database through a SQL Order By clause. However, if the getSortCriteria method does return a sort criteria the framework will perform in memory sorting which is what we need to achieve sorting by region name. So, inside this method we need to evaluate the Order By clause, and if the order by column matches an attribute that has a model-based LOV choicelist defined with a display attribute that is different from the value attribute, we need to return a sort criterria. Here is the complete code of this method: public SortCriteria[] getSortCriteria() {   String orderBy = getOrderByClause();          if (orderBy!=null )   {     boolean descending = false;     if (orderBy.endsWith(" DESC"))      {       descending = true;       orderBy = orderBy.substring(0,orderBy.length()-5);     }     // extract column name, is part after the dot     int dotpos = orderBy.lastIndexOf(".");     String columnName = orderBy.substring(dotpos+1);     // loop over attributes and find matching attribute     AttributeDef orderByAttrDef = null;     for (AttributeDef attrDef : getAttributeDefs())     {       if (columnName.equals(attrDef.getColumnName()))       {         orderByAttrDef = attrDef;         break;       }     }     if (orderByAttrDef!=null && "choice".equals(orderByAttrDef.getProperty("CONTROLTYPE"))          && orderByAttrDef.getListBindingDef()!=null)     {       String orderbyAttr = orderByAttrDef.getName();       String[] displayAttrs = orderByAttrDef.getListBindingDef().getListDisplayAttrNames();       String[] listAttrs = orderByAttrDef.getListBindingDef().getListAttrNames();       // if first list display attributes is not the same as first list attribute, than the value       // displayed is different from the value copied back to the order by attribute, in which case we need to       // use our custom comparator       if (displayAttrs!=null && listAttrs!=null && displayAttrs.length>0 && !displayAttrs[0].equals(listAttrs[0]))       {                  SortCriteriaImpl sc1 = new SortCriteriaImpl(orderbyAttr, descending);         SortCriteria[] sc = new SortCriteriaImpl[]{sc1};         return sc;                           }     }     }   return super.getSortCriteria(); } If this method returns a sort criteria, then the framework will call the sort method on the view object. The sort method uses a Comparator object to determine the sequence in which the rows should be returned. This comparator is retrieved by calling the getRowComparator method on the view object. So, to ensure sorting by our display value, we need to override this method to return our custom comparator: public Comparator getRowComparator() {   return new LovDisplayAttributeRowComparator(getSortCriteria()); } The custom comparator class extends the default RowComparator class and overrides the method compareRows and looks up the choice display value to compare the two rows. The complete code of this class is included in the sample application.  With this code in place, clicking on the Region sort icon nicely sorts the countries by RegionName, as you can see below. When using the Query-By-Example table filter at the top of the table, you typically want to use the same choice list to filter the rows. One way to do that is documented in ADF code corner sample 16 - How To Customize the ADF Faces Table Filter.The solution in this sample is perfectly fine to use. This sample requires you to define a separate iterator binding and associated tree binding to populate the choice list in the table filter area using the af:iterator tag. You might be able to reuse the same LOV view object instance in this iterator binding that is used as view accessor for the model-bassed LOV. However, I have seen quite a few customers who have a generic LOV view object (mapped to one "refcodes" table) with the bind variable values set in the LOV view accessor. In such a scenario, some duplicate work is needed to get a dedicated view object instance with the correct bind variables that can be used in the iterator binding. Looking for ways to maximize reuse, wouldn't it be nice if we could just reuse our model-based LOV to populate this filter choice list? Well we can. Here are the basic steps: 1. Create an attribute list binding in the page definition that we can use to retrieve the list of SelectItems needed to populate the choice list <list StaticList="false" Uses="LOV_RegionId"               IterBinding="CountriesView1Iterator" id="RegionId"/>  We need this "current row" list binding because the implicit list binding used by the item in the table is not accessible outside a table row, we cannot use the expression #{row.bindings.RegionId} in the table filter facet. 2. Create a Map-style managed bean with the get method retrieving the list binding as key, and returning the list of SelectItems. To return this list, we take the list of selectItems contained by the list binding and replace the index number that is normally used as key value with the actual attribute value that is set by the choice list. Here is the code of the get method:  public Object get(Object key) {   if (key instanceof FacesCtrlListBinding)   {     // we need to cast to internal class FacesCtrlListBinding rather than JUCtrlListBinding to     // be able to call getItems method. To prevent this import, we could evaluate an EL expression     // to get the list of items     FacesCtrlListBinding lb = (FacesCtrlListBinding) key;     if (cachedFilterLists.containsKey(lb.getName()))     {       return cachedFilterLists.get(lb.getName());     }     List<SelectItem> items = (List<SelectItem>)lb.getItems();     if (items==null || items.size()==0)     {       return items;     }     List<SelectItem> newItems = new ArrayList<SelectItem>();     JUCtrlValueDef def = ((JUCtrlValueDef)lb.getDef());     String valueAttr = def.getFirstAttrName();     // the items list has an index number as value, we need to replace this with the actual     // value of the attribute that is copied back by the choice list     for (int i = 0; i < items.size(); i++)     {       SelectItem si = (SelectItem) items.get(i);       Object value = lb.getValueFromList(i);       if (value instanceof Row)       {         Row row = (Row) value;         si.setValue(row.getAttribute(valueAttr));                 }       else       {         // this is the "empty" row, set value to empty string so all rows will be returned         // as user no longer wants to filter on this attribute         si.setValue("");       }       newItems.add(si);     }     cachedFilterLists.put(lb.getName(), newItems);     return newItems;   }   return null; } Note that we added caching to speed up performance, and to handle the situation where table filters or search criteria are set such that no rows are retrieved in the table. When there are no rows, there is no current row and the getItems method on the list binding will return no items.  An alternative approach to create the list of SelectItems would be to retrieve the iterator binding from the list binding and loop over the rows in the iterator binding rowset. Then we wouldn't need the import of the ADF internal oracle.adfinternal.view.faces.model.binding.FacesCtrlListBinding class, but then we need to figure out the display attributes from the list binding definition, and possible separate them with a dash if multiple display attributes are defined in the LOV. Doable but less reuse and more work. 3. Inside the filter facet for the column create an af:selectOneChoice with the value property of the f:selectItems tag referencing the get method of the managed bean:  <f:facet name="filter">   <af:selectOneChoice id="soc0" autoSubmit="true"                       value="#{vs.filterCriteria.RegionId}">     <!-- attention: the RegionId list binding must be created manually in the page definition! -->                       <f:selectItems id="si0"                    value="#{viewScope.TableFilterChoiceList[bindings.RegionId]}"/>   </af:selectOneChoice> </f:facet> Note that the managed bean is defined in viewScope for the caching to take effect. Here is a screen shot of the tabe filter in action: You can download the sample application here. 

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