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  • Java Singleton Pattern

    - by Spencer
    I'm used the Singleton Design Pattern public class Singleton { private static final Singleton INSTANCE = new Singleton(); // Private constructor prevents instantiation from other classes private Singleton() {} public static Singleton getInstance() { return INSTANCE; } } My question is how do I create an object of class Singleton in another class? I've tried: Singleton singleton = new Singleton(); // error - constructor is private Singleton singleton = Singleton.getInstance(); // error - non-static method cannot be referenced from a static context What is the correct code? Thanks, Spencer

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  • NSObjectController confusion binding to a class property. Help!

    - by scottw
    Hi, I'm teaching myself cocoa and enjoying the experience most of the time. I have been struggling all day with a simple problem that google has let me down on. I have read the Cocoa Bindings Program Topics and think I grok it but still can't solve my issue. I have a very simple class called MTSong that has various properties. I have used @synthesize to create getter/setters and can use KVC to change properties. i.e in my app controller the following works: mySong = [[MTSong alloc]init]; [mySong setValue:@"2" forKey:@"version"]; In case I am doing something noddy in my class code MTSong.h is: #import <Foundation/Foundation.h> @interface MTSong : NSObject { NSNumber *version; NSString *name; } @property(readwrite, assign) NSNumber *version; @property(readwrite, assign) NSString *name; @end and MTSong.m is: #import "MTSong.h" @implementation MTSong - (id)init { [super init]; return self; } - (void)dealloc { [super dealloc]; } @synthesize version; @synthesize name; @end In Interface Builder I have a label (NSTextField) that I want to update whenever I use KVC to change the version of the song. I do the following: Drag NSObjectController object into the doc window and in the Inspector-Attributes I set: Mode: Class Class Name: MTSong Add a key called version and another called name Go to Inspector-Bindings-Controller Content Bind To: File's Owner (Not sure this is right...) Model Key Path: version Select the cell of the label and go to Inspector Bind to: Object Controller Controller Key: mySong Model Key Path: version I have attempted changing the Model Key Path in step 2 to "mySong" which makes more sense but the compiler complains. Any suggestions would be greatly appreciated. Scott Update Post Comments I wasn't exposing mySong property so have changed my AppController.h to be: #import <Cocoa/Cocoa.h> @class MTSong; @interface AppController : NSObject { IBOutlet NSButton *start; IBOutlet NSTextField *tf; MTSong *mySong; } -(IBAction)convertFile:(id)sender; @end I suspect File's owner was wrong as I am not using a document based application and I need to bind to the AppController, so step 2 is now: Go to Inspector-Bindings-Controller Content Bind To: App Controller Model Key Path: mySong I needed to change 3. to Select the cell of the label and go to Inspector Bind to: Object Controller Controller Key: selection Model Key Path: version All compiles and is playing nice!

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  • Casting interfaces in java

    - by owca
    I had two separate interfaces, one 'MultiLingual' for choosing language of text to return, and second 'Justification' to justify returned text. Now I need to join them, but I'm stuck at 'java.lang.ClassCastException' error. Class Book is not important here. Data.length and FormattedInt.width correspond to the width of the line. The code : public interface MultiLingual { static int ENG = 0; static int PL = 1; String get(int lang); int setLength(int length); } class Book implements MultiLingual { private String title; private String publisher; private String author; private int jezyk; public Book(String t, String a, String p, int y){ this(t, a, p, y, 1); } public Book(String t, String a, String p, int y, int lang){ title = t; author = a; publisher = p; jezyk = lang; } public String get(int lang){ jezyk = lang; return this.toString(); } public int setLength(int i){ return 0; } @Override public String toString(){ String dane; if (jezyk == ENG){ dane = "Author: "+this.author+"\n"+ "Title: "+this.title+"\n"+ "Publisher: "+this.publisher+"\n"; } else { dane = "Autor: "+this.author+"\n"+ "Tytul: "+this.title+"\n"+ "Wydawca: "+this.publisher+"\n"; } return dane; } } class Data implements MultiLingual { private int day; private int month; private int year; private int jezyk; private int length; public Data(int d, int m, int y){ this(d, m, y, 1); } public Data(int d, int m, int y, int lang){ day = d; month = m; year = y; jezyk = lang; } public String get(int lang){ jezyk = lang; return this.toString(); } public int setLength(int i){ length = i; return length; } @Override public String toString(){ String dane=""; String miesiac=""; String dzien=""; switch(month){ case 1: miesiac="January"; case 2: miesiac="February"; case 3: miesiac="March"; case 4: miesiac="April"; case 5: miesiac="May"; case 6: miesiac="June"; case 7: miesiac="July"; case 8: miesiac="August"; case 9: miesiac="September"; case 10: miesiac="October"; case 11: miesiac="November"; case 12: miesiac="December"; } if(day==1){ dzien="st"; } if(day==2 || day==22){ dzien="nd"; } if(day==3 || day==23){ dzien="rd"; } else{ dzien="th"; } if(jezyk==ENG){ dane =this.day+dzien+" of "+miesiac+" "+this.year; } else{ dane = this.day+"."+this.month+"."+this.year; } return dane; } } interface Justification { static int RIGHT=1; static int LEFT=2; static int CENTER=3; String justify(int just); } class FormattedInt implements Justification { private int liczba; private int width; private int wyrownanie; public FormattedInt(int s, int i){ liczba = s; width = i; wyrownanie = 2; } public String justify(int just){ wyrownanie = just; String wynik=""; String tekst = Integer.toString(liczba); int len = tekst.length(); int space_left=width - len; int space_right = space_left; int space_center_left = (width - len)/2; int space_center_right = width - len - space_center_left -1; String puste=""; if(wyrownanie == LEFT){ for(int i=0; i<space_right; i++){ puste = puste + " "; } wynik = tekst+puste; } else if(wyrownanie == RIGHT){ for(int i=0; i<space_left; i++){ puste = puste + " "; } wynik = puste+tekst; } else if(wyrownanie == CENTER){ for(int i=0; i<space_center_left; i++){ puste = puste + " "; } wynik = puste + tekst; puste = " "; for(int i=0; i< space_center_right; i++){ puste = puste + " "; } wynik = wynik + puste; } return wynik; } } And the test code that shows this casting "(Justification)gatecrasher[1]" which gives me errors : MultiLingual gatecrasher[]={ new Data(3,12,1998), new Data(10,6,1924,MultiLingual.ENG), new Book("Sekret","Rhonda Byrne", "Nowa proza",2007), new Book("Tuesdays with Morrie", "Mitch Albom", "Time Warner Books",2003, MultiLingual.ENG), }; gatecrasher[0].setLength(25); gatecrasher[1].setLength(25); Justification[] t={ new FormattedInt(345,25), (Justification)gatecrasher[1], (Justification)gatecrasher[0], new FormattedInt(-7,25) }; System.out.println(" 10 20 30"); System.out.println("123456789 123456789 123456789"); for(int i=0;i < t.length;i++) System.out.println(t[i].justify(Justification.RIGHT)+"<----\n");

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  • How to improve the builder pattern?

    - by tangens
    Motivation Recently I searched for a way to initialize a complex object without passing a lot of parameter to the constructor. I tried it with the builder pattern, but I don't like the fact, that I'm not able to check at compile time if I really set all needed values. Traditional builder pattern When I use the builder pattern to create my Complex object, the creation is more "typesafe", because it's easier to see what an argument is used for: new ComplexBuilder() .setFirst( "first" ) .setSecond( "second" ) .setThird( "third" ) ... .build(); But now I have the problem, that I can easily miss an important parameter. I can check for it inside the build() method, but that is only at runtime. At compile time there is nothing that warns me, if I missed something. Enhanced builder pattern Now my idea was to create a builder, that "reminds" me if I missed a needed parameter. My first try looks like this: public class Complex { private String m_first; private String m_second; private String m_third; private Complex() {} public static class ComplexBuilder { private Complex m_complex; public ComplexBuilder() { m_complex = new Complex(); } public Builder2 setFirst( String first ) { m_complex.m_first = first; return new Builder2(); } public class Builder2 { private Builder2() {} Builder3 setSecond( String second ) { m_complex.m_second = second; return new Builder3(); } } public class Builder3 { private Builder3() {} Builder4 setThird( String third ) { m_complex.m_third = third; return new Builder4(); } } public class Builder4 { private Builder4() {} Complex build() { return m_complex; } } } } As you can see, each setter of the builder class returns a different internal builder class. Each internal builder class provides exactly one setter method and the last one provides only a build() method. Now the construction of an object again looks like this: new ComplexBuilder() .setFirst( "first" ) .setSecond( "second" ) .setThird( "third" ) .build(); ...but there is no way to forget a needed parameter. The compiler wouldn't accept it. Optional parameters If I had optional parameters, I would use the last internal builder class Builder4 to set them like a "traditional" builder does, returning itself. Questions Is this a well known pattern? Does it have a special name? Do you see any pitfalls? Do you have any ideas to improve the implementation - in the sense of fewer lines of code?

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  • How can I add headers to DualList control wpf

    - by devnet247
    Hi all I am trying to write a Dual List usercontrol in wpf. I am new to wpf and I am finding it quite difficult. This is something I have put together in a couple of hours.It's not that good but a start. I would be extremely grateful if somebody with wpf experience could improve it. The aim is to simplify the usage as much as possible I am kind of stuck. I would like the user of the DualList Control to be able to set up headers how do you do that. Do I need to expose some dependency properties in my control? At the moment when loading the user has to pass a ObservableCollection is there a better way? Could you have a look and possibly make any suggestions with some code? Thanks a lot!!!!! xaml <Grid ShowGridLines="False"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*"/> <ColumnDefinition Width="25px"></ColumnDefinition> <ColumnDefinition Width="*"/> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="*"></RowDefinition> </Grid.RowDefinitions> <StackPanel Orientation="Vertical" Grid.Column="0" Grid.Row="0"> <Label Name="lblLeftTitle" Content="Available"></Label> <ListView Name="lvwLeft"> </ListView> </StackPanel> <WrapPanel Grid.Column="1" Grid.Row="0"> <Button Name="btnMoveRight" Content=">" Width="25" Margin="0,35,0,0" Click="btnMoveRight_Click" /> <Button Name="btnMoveAllRight" Content=">>" Width="25" Margin="0,05,0,0" Click="btnMoveAllRight_Click" /> <Button Name="btnMoveLeft" Content="&lt;" Width="25" Margin="0,25,0,0" Click="btnMoveLeft_Click" /> <Button Name="btnMoveAllLeft" Content="&lt;&lt;" Width="25" Margin="0,05,0,0" Click="btnMoveAllLeft_Click" /> </WrapPanel> <StackPanel Orientation="Vertical" Grid.Column="2" Grid.Row="0"> <Label Name="lblRightTitle" Content="Selected"></Label> <ListView Name="lvwRight"> </ListView> </StackPanel> </Grid> Client public partial class DualListTest { public ObservableCollection<ListViewItem> LeftList { get; set; } public ObservableCollection<ListViewItem> RightList { get; set; } public DualListTest() { InitializeComponent(); LoadCustomers(); LoadDualList(); } private void LoadDualList() { dualList1.Load(LeftList, RightList); } private void LoadCustomers() { //Pretend we are getting a list of Customers from a repository. //Some go in the left List(Good Customers) some go in the Right List(Bad Customers). LeftList = new ObservableCollection<ListViewItem>(); RightList = new ObservableCollection<ListViewItem>(); var customers = GetCustomers(); foreach (var customer in customers) { if (customer.Status == CustomerStatus.Good) { LeftList.Add(new ListViewItem { Content = customer }); } else { RightList.Add(new ListViewItem{Content=customer }); } } } private static IEnumerable<Customer> GetCustomers() { return new List<Customer> { new Customer {Name = "Jo Blogg", Status = CustomerStatus.Good}, new Customer {Name = "Rob Smith", Status = CustomerStatus.Good}, new Customer {Name = "Michel Platini", Status = CustomerStatus.Good}, new Customer {Name = "Roberto Baggio", Status = CustomerStatus.Good}, new Customer {Name = "Gio Surname", Status = CustomerStatus.Bad}, new Customer {Name = "Diego Maradona", Status = CustomerStatus.Bad} }; } } UserControl public partial class DualList:UserControl { public ObservableCollection<ListViewItem> LeftListCollection { get; set; } public ObservableCollection<ListViewItem> RightListCollection { get; set; } public DualList() { InitializeComponent(); } public void Load(ObservableCollection<ListViewItem> leftListCollection, ObservableCollection<ListViewItem> rightListCollection) { LeftListCollection = leftListCollection; RightListCollection = rightListCollection; lvwLeft.ItemsSource = leftListCollection; lvwRight.ItemsSource = rightListCollection; EnableButtons(); } public static DependencyProperty LeftTitleProperty = DependencyProperty.Register("LeftTitle", typeof(string), typeof(Label)); public static DependencyProperty RightTitleProperty = DependencyProperty.Register("RightTitle", typeof(string), typeof(Label)); public static DependencyProperty LeftListProperty = DependencyProperty.Register("LeftList", typeof(ListView), typeof(DualList)); public static DependencyProperty RightListProperty = DependencyProperty.Register("RightList", typeof(ListView), typeof(DualList)); public string LeftTitle { get { return (string)lblLeftTitle.Content; } set { lblLeftTitle.Content = value; } } public string RightTitle { get { return (string)lblRightTitle.Content; } set { lblRightTitle.Content = value; } } public ListView LeftList { get { return lvwLeft; } set { lvwLeft = value; } } public ListView RightList { get { return lvwRight; } set { lvwRight = value; } } private void EnableButtons() { if (lvwLeft.Items.Count > 0) { btnMoveRight.IsEnabled = true; btnMoveAllRight.IsEnabled = true; } else { btnMoveRight.IsEnabled = false; btnMoveAllRight.IsEnabled = false; } if (lvwRight.Items.Count > 0) { btnMoveLeft.IsEnabled = true; btnMoveAllLeft.IsEnabled = true; } else { btnMoveLeft.IsEnabled = false; btnMoveAllLeft.IsEnabled = false; } if (lvwLeft.Items.Count != 0 || lvwRight.Items.Count != 0) return; btnMoveLeft.IsEnabled = false; btnMoveAllLeft.IsEnabled = false; btnMoveRight.IsEnabled = false; btnMoveAllRight.IsEnabled = false; } private void MoveRight() { while (lvwLeft.SelectedItems.Count > 0) { var selectedItem = (ListViewItem)lvwLeft.SelectedItem; LeftListCollection.Remove(selectedItem); RightListCollection.Add(selectedItem); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveAllRight() { while (lvwLeft.Items.Count > 0) { var item = (ListViewItem)lvwLeft.Items[lvwLeft.Items.Count - 1]; LeftListCollection.Remove(item); RightListCollection.Add(item); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveAllLeft() { while (lvwRight.Items.Count > 0) { var item = (ListViewItem)lvwRight.Items[lvwRight.Items.Count - 1]; RightListCollection.Remove(item); LeftListCollection.Add(item); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void MoveLeft() { while (lvwRight.SelectedItems.Count > 0) { var selectedCustomer = (ListViewItem)lvwRight.SelectedItem; LeftListCollection.Add(selectedCustomer); RightListCollection.Remove(selectedCustomer); } lvwRight.ItemsSource = RightListCollection; lvwLeft.ItemsSource = LeftListCollection; EnableButtons(); } private void btnMoveLeft_Click(object sender, RoutedEventArgs e) { MoveLeft(); } private void btnMoveAllLeft_Click(object sender, RoutedEventArgs e) { MoveAllLeft(); } private void btnMoveRight_Click(object sender, RoutedEventArgs e) { MoveRight(); } private void btnMoveAllRight_Click(object sender, RoutedEventArgs e) { MoveAllRight(); } }

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  • Eclipselink read complex object model in an ordered way

    - by Raven
    Hi, I need to read a complex model in an ordered way with eclipselink. The order is mandantory because it is a huge database and I want to have an output of a small portion of the database in a jface tableview. Trying to reorder it in the loading/quering thread takes too long and ordering it in the LabelProvider blocks the UI thread too much time, so I thought if Eclipselink could be used that way, that the database will order it, it might give me the performance I need. Unfortunately the object model can not be changed :-( The model is something like: @SuppressWarnings("serial") @Entity public class Thing implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; @OneToMany(cascade=CascadeType.ALL) @PrivateOwned private List<Property> properties = new ArrayList<Property>(); ... // getter and setter following here } public class Property implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; @OneToOne private Item item; private String value; ... // getter and setter following here } public class Item implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; .... // getter and setter following here } // Code end In the table view the y-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Thing m ORDER BY m.name ASC"); using the "name" attribute from the Thing objects as label. In the table view the x-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Item m ORDER BY m.name ASC"); using the "name" attribute from the Item objects as label. Each cell has the value Things.getProperties().get[x].getValue() Unfortunately the list "properties" is not ordered, so the combination of cell value and x-axis column number (x) is not necessarily correct. Therefore I need to order the list "properties" in the same way as I ordered the labeling of the x-axis. And exactly this is the thing I dont know how it is done. So querying for the Thing objects should return the list "properties" "ORDER BY name ASC" but of the "Item"s objects. My ideas are something like having a query with two JOINs. Joing Things with Property and with Item but somehow I was unable to get it to work yet. Thank you for your help and your ideas to solve this riddle.

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  • Problem with eager load polymorphic associations using Linq and NHibernate

    - by Voislav
    Is it possible to eagerly load polymorphic association using Linq and NH? For example: Company is base class, Department is inherited from Company, and Company has association Employees to the User (one-to-many) and also association to the Country (many-to-one). Here is mapping part related to inherited class (without User and Country classes): <class name="Company" discriminator-value="Company"> <id name="Id" type="int" unsaved-value="0" access="nosetter.camelcase-underscore"> <generator class="native"></generator> </id> <discriminator column="OrganizationUnit" type="string" length="10" not-null="true"/> <property name="Name" type="string" length="50" not-null="true"/> <many-to-one name="Country" class="Country" column="CountryId" not-null ="false" foreign-key="FK_Company_CountryId" access="field.camelcase-underscore" /> <set name="Departments" inverse="true" lazy="true" access="field.camelcase-underscore"> <key column="DepartmentParentId" not-null="false" foreign-key="FK_Department_DepartmentParentId"></key> <one-to-many class="Department"></one-to-many> </set> <set name="Employees" inverse="true" lazy="true" access="field.camelcase-underscore"> <key column="CompanyId" not-null="false" foreign-key="FK_User_CompanyId"></key> <one-to-many class="User"></one-to-many> </set> <subclass name="Department" extends="Company" discriminator-value="Department"> <many-to-one name="DepartmentParent" class="Company" column="DepartmentParentId" not-null ="false" foreign-key="FK_Department_DepartmentParentId" access="field.camelcase-underscore" /> </subclass> </class> I do not have problem to eagerly load any of the association on the Company: Session.Query<Company>().Where(c => c.Name == "Main Company").Fetch(c => c.Country).Single(); Session.Query<Company>().Where(c => c.Name == "Main Company").FetchMany(c => c.Employees).Single(); Also, I could eagerly load not-polymorphic association on the department: Session.Query<Department>().Where(d => d.Name == "Department 1").Fetch(d => d.DepartmentParent).Single(); But I get NullReferenceException when I try to eagerly load any of the polymorphic association (from the Department): Assert.Throws<NullReferenceException>(() => Session.Query<Department>().Where(d => d.Name == "Department 1").Fetch(d => d.Country).Single()); Assert.Throws<NullReferenceException>(() => Session.Query<Department>().Where(d => d.Name == "Department 1").FetchMany(d => d.Employees).Single()); Am I doing something wrong or this is not supported yet?

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  • Composit widget - what is the preffered way?

    - by Aleksander Gralak
    I want to build reusable widget. It should be ordinal composite of standard elements. What is the best approach. Below is the code sample which I use currently, however there might be something more elegant. Furthermore the sample below runs perfectly in runtime, but visual editor in Eclipse is throwing exceptions (which is not a problem for me at this time). Is there any recommended way of creating composites? Should I use fragment? public class MyComposite extends LinearLayout { private ImageView m_a1; private ImageView m_a2; private ImageView m_w1; private ImageView m_w2; private ImageView m_w3; private ImageView m_w4; public CallBackSlider(final Context context) { this(context, null); } public CallBackSlider(final Context context, final AttributeSet attrs) { super(context, attrs); LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); inflater.inflate(R.layout.my_composite, this, true); setupViewItems(); } private void setupViewItems() { m_a1 = (ImageView) findViewById(R.id.A1Img); m_w1 = (ImageView) findViewById(R.id.Wave1Img); m_w2 = (ImageView) findViewById(R.id.Wave2Img); m_w3 = (ImageView) findViewById(R.id.Wave3Img); m_w4 = (ImageView) findViewById(R.id.Wave4Img); m_a2 = (ImageView) findViewById(R.id.A2Img); resetView(); } private void resetView() { m_w1.setAlpha(0); m_w2.setAlpha(0); m_w3.setAlpha(0); m_w4.setAlpha(0); } } Layout xml: <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/MyComposite" ... > <ImageView android:id="@+id/A1Img" android:src="@drawable/a1" ... /> <ImageView android:id="@+id/Wave1Img" ... android:src="@drawable/wave1" /> <ImageView android:id="@+id/Wave2Img" ... android:src="@drawable/wave2" /> <ImageView android:id="@+id/Wave3Img" ... android:src="@drawable/wave3" /> <ImageView android:id="@+id/Wave4Img" ... android:src="@drawable/wave4" /> <ImageView android:id="@+id/EarImg" ... android:src="@drawable/a2" /> </LinearLayout> Then you can use it in other layouts like this: ... <your.package.MyComposite android:id="@+id/mc1" ... /> ... And use from java code as well as instance of MyComposite class.

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  • TreeView in Winforms and focus problem

    - by Marcus
    Hi, Can anyone please explain to my why the form in the code below gets out of focus when selecting a treenode in the tree? What should happen is that the form/button should get the focus when the tree disappears like the listview example but it doesn't. Code example: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace FocusTest { public partial class Form1 : Form { #region Generated /// <summary> /// Required designer variable. /// </summary> private System.ComponentModel.IContainer components = null; /// <summary> /// Clean up any resources being used. /// </summary> /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// </summary> private void InitializeComponent() { System.Windows.Forms.ListViewItem listViewItem1 = new System.Windows.Forms.ListViewItem("Item1"); System.Windows.Forms.ListViewItem listViewItem2 = new System.Windows.Forms.ListViewItem("Item2"); System.Windows.Forms.ListViewItem listViewItem3 = new System.Windows.Forms.ListViewItem("Item3"); System.Windows.Forms.TreeNode treeNode1 = new System.Windows.Forms.TreeNode("Node0"); System.Windows.Forms.TreeNode treeNode2 = new System.Windows.Forms.TreeNode("Node1"); System.Windows.Forms.TreeNode treeNode3 = new System.Windows.Forms.TreeNode("Node2"); this.button1 = new System.Windows.Forms.Button(); this.listView1 = new System.Windows.Forms.ListView(); this.button2 = new System.Windows.Forms.Button(); this.treeView1 = new System.Windows.Forms.TreeView(); this.SuspendLayout(); // // button1 // this.button1.Location = new System.Drawing.Point(12, 12); this.button1.Name = "button1"; this.button1.Size = new System.Drawing.Size(75, 23); this.button1.TabIndex = 0; this.button1.Text = "button1"; this.button1.UseVisualStyleBackColor = true; this.button1.Click += new System.EventHandler(this.button1_Click); // // listView1 // this.listView1.Items.AddRange(new System.Windows.Forms.ListViewItem[] { listViewItem1, listViewItem2, listViewItem3 }); this.listView1.Location = new System.Drawing.Point(12, 41); this.listView1.Name = "listView1"; this.listView1.Size = new System.Drawing.Size(121, 97); this.listView1.TabIndex = 1; this.listView1.UseCompatibleStateImageBehavior = false; this.listView1.Visible = false; this.listView1.SelectedIndexChanged += new System.EventHandler(this.listView1_SelectedIndexChanged); this.listView1.View = View.List; // // button2 // this.button2.Location = new System.Drawing.Point(310, 11); this.button2.Name = "button2"; this.button2.Size = new System.Drawing.Size(75, 23); this.button2.TabIndex = 2; this.button2.Text = "button2"; this.button2.UseVisualStyleBackColor = true; this.button2.Click += new System.EventHandler(this.button2_Click); // // treeView1 // this.treeView1.Location = new System.Drawing.Point(310, 41); this.treeView1.Name = "treeView1"; treeNode1.Name = "Node0"; treeNode1.Text = "Node0"; treeNode2.Name = "Node1"; treeNode2.Text = "Node1"; treeNode3.Name = "Node2"; treeNode3.Text = "Node2"; this.treeView1.Nodes.AddRange(new System.Windows.Forms.TreeNode[] { treeNode1, treeNode2, treeNode3}); this.treeView1.Size = new System.Drawing.Size(121, 97); this.treeView1.TabIndex = 3; this.treeView1.Visible = false; this.treeView1.AfterSelect += new System.Windows.Forms.TreeViewEventHandler(this.treeView1_AfterSelect); // // Form1 // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(760, 409); this.Controls.Add(this.treeView1); this.Controls.Add(this.button2); this.Controls.Add(this.listView1); this.Controls.Add(this.button1); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); } #endregion private System.Windows.Forms.Button button1; private System.Windows.Forms.ListView listView1; private System.Windows.Forms.Button button2; private System.Windows.Forms.TreeView treeView1; #endregion public Form1() { InitializeComponent(); } #region TreeView private void button2_Click(object sender, EventArgs e) { ToggleTreeView(); } private void ToggleTreeView() { if (treeView1.Visible) { Controls.Remove(treeView1); treeView1.Visible = false; } else { Controls.Add(treeView1); treeView1.Size = new Size(300, 400); treeView1.Location = PointToClient(PointToScreen(new System.Drawing.Point(button2.Location.X, button2.Location.Y + button2.Height))); this.treeView1.BringToFront(); treeView1.Visible = true; treeView1.Select(); } } private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { ToggleTreeView(); } #endregion #region ListView private void button1_Click(object sender, EventArgs e) { ToggleListView(); } private void ToggleListView() { if (listView1.Visible) { Controls.Remove(listView1); listView1.Visible = false; } else { Controls.Add(listView1); listView1.Size = new Size(300, 400); listView1.Location = PointToClient(PointToScreen(new System.Drawing.Point(button1.Location.X, button1.Location.Y + button1.Height))); this.listView1.BringToFront(); listView1.Visible = true; listView1.Select(); } } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { if (listView1.Visible) ToggleListView(); } #endregion } }

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  • Approaches to create a nested tree structure of NSDictionaries?

    - by d11wtq
    I'm parsing some input which produces a tree structure containing NSDictionary instances on the branches and NSString instance at the nodes. After parsing, the whole structure should be immutable. I feel like I'm jumping through hoops to create the structure and then make sure it's immutable when it's returned from my method. We can probably all relate to the input I'm parsing, since it's a query string from a URL. In a string like this: a=foo&b=bar&a=zip We expect a structure like this: NSDictionary { "a" => NSDictionary { 0 => "foo", 1 => "zip" }, "b" => "bar" } I'm keeping it just two-dimensional in this example for brevity, though in the real-world we sometimes see var[key1][key2]=value&var[key1][key3]=value2 type structures. The code hasn't evolved that far just yet. Currently I do this: - (NSDictionary *)parseQuery:(NSString *)queryString { NSMutableDictionary *params = [NSMutableDictionary dictionary]; NSArray *pairs = [queryString componentsSeparatedByString:@"&"]; for (NSString *pair in pairs) { NSRange eqRange = [pair rangeOfString:@"="]; NSString *key; id value; // If the parameter is a key without a specified value if (eqRange.location == NSNotFound) { key = [pair stringByReplacingPercentEscapesUsingEncoding:NSASCIIStringEncoding]; value = @""; } else { // Else determine both key and value key = [[pair substringToIndex:eqRange.location] stringByReplacingPercentEscapesUsingEncoding:NSASCIIStringEncoding]; if ([pair length] > eqRange.location + 1) { value = [[pair substringFromIndex:eqRange.location + 1] stringByReplacingPercentEscapesUsingEncoding:NSASCIIStringEncoding]; } else { value = @""; } } // Parameter already exists, it must be a dictionary if (nil != [params objectForKey:key]) { id existingValue = [params objectForKey:key]; if (![existingValue isKindOfClass:[NSDictionary class]]) { value = [NSDictionary dictionaryWithObjectsAndKeys:existingValue, [NSNumber numberWithInt:0], value, [NSNumber numberWithInt:1], nil]; } else { // FIXME: There must be a more elegant way to build a nested dictionary where the end result is immutable? NSMutableDictionary *newValue = [NSMutableDictionary dictionaryWithDictionary:existingValue]; [newValue setObject:value forKey:[NSNumber numberWithInt:[newValue count]]]; value = [NSDictionary dictionaryWithDictionary:newValue]; } } [params setObject:value forKey:key]; } return [NSDictionary dictionaryWithDictionary:params]; } If you look at the bit where I've added FIXME it feels awfully clumsy, pulling out the existing dictionary, creating an immutable version of it, adding the new value, then creating an immutable dictionary from that to set back in place. Expensive and unnecessary? I'm not sure if there are any Cocoa-specific design patterns I can follow here?

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  • How to handle float values in a plist

    - by Banjer
    I'm reading in a plist from a web server, generated with some php. When I read that into an NSArray in my iphone app, and then spit the NSArray out with NSLog to check it out, I see that the float values are treated as strings. I would like the "distance" values to be treated as numeric and not strings. This plist is displayed in a table view where it can be sorted by distance, but the problem is is distance is sorted as a string, so I get some funny sorting results. Can I convert the distance values to float from string in the NSArray? Or maybe theres a simpler solution like tweaking the plist definition, or maybe something in the NSMutableURLRequest code? My plist looks like this: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <array> <dict> <key>name</key> <string>Pizza Joint</string> <key>distance</key> <string>2.1</string> </dict> <dict> <key>name</key> <string>Burger Kang</string> <key>distance</key> <string>5</string> </dict> </array> </plist> After reading it into an NSArray, it looks like this per NSLog: result: ( { distance = "2.1"; name = "Pizza Joint"; }, { distance = 5; name = "Burger Kang"; } ) Here is the Objective-C code that retrieves the plist: // Set up url request // postData and postLength are left out, but I can post in this question if needed. NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease]; [request setURL:[NSURL URLWithString:@"http://mysite.com/get_plist.php"]]; [request setHTTPMethod:@"POST"]; [request setValue:postLength forHTTPHeaderField:@"Content-Length"]; [request setValue:@"application/x-www-form-urlencoded charset=utf-8" forHTTPHeaderField:@"Content-Type"]; [request setHTTPBody:postData]; NSError *error; NSURLResponse *response; NSData *result = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error]; NSString *string = [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding]; // libraryContent is an NSArray self.libraryContent = [string propertyList]; NSLog(@"result: %@", self.libraryContent);

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  • How to write this Linq SQL as a Dynamic Query (using strings)?

    - by Dr. Zim
    Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Product Sizes to only show hammer sizes. Current setup: I created a query object, sent it to a repository, and fed each option to a SQL "table valued function" where null values represent "get all products". I consider this a good effort, but far from DDD acceptable. I want to avoid any "programming" in SQL, hopefully doing everything with a repository. Comments on this topic would be appreciated. Specific question: How would I rewrite this query as a Dynamic Query? A link to something like 101 Linq Examples would be fantastic, but with a Dynamic Query scope. I really want to pass to this method the field in quotes "" for which I want a list of options and how many products have that option. from p in db.Products group p by p.ProductSize into g select new Category { PropertyType = g.Key, Count = g.Count() } Each DDL option will have "The selection (21)" where the (21) is the quantity of products that have that attribute. Upon selecting an option, all other remaining DDLs will update with the remaining options and counts. Edit: Additional notes: .OrderBy("it.City") // "it" refers to the entire record .GroupBy("City", "new(City)") // This produces a unique list of City .Select("it.Count()") //This gives a list of counts... getting closer .Select("key") // Selects a list of unique City .Select("new (key, count() as string)") // +1 to me LOL. key is a row of group .GroupBy("new (City, Manufacturer)", "City") // New = list of fields to group by .GroupBy("City", "new (Manufacturer, Size)") // Second parameter is a projection Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it.count() as string)")// GroupBy new makes key an object Product .Where("ProductType == @0", "Maps") .GroupBy("new(City)", "new ( null as string)")// Projection not available later? .Select("new (key.City, it as object)")// the it object is the result of GroupBy var a = Product .Where("ProductType == @0", "Maps") .GroupBy("@0", "it", "City") // This fails to group Product at all .Select("new ( Key, it as Product )"); // "it" is property cast though What I have learned so far is LinqPad is fantastic, but still looking for an answer. Eventually, completely random research like this will prevail I guess. LOL. Edit:

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  • Streaming webcam video in Flash using MP4 encoding

    - by Herms
    One of the features of the Flash app I'm working on is to be able to stream a webcam to others. We're just using the built-in webcam support in Flash and sending it through FMS. We've had some people ask for higher quality video, but we're already using the highest quality setting we can in Flash (setting quality to 100%). My understanding is that in the newer flash players they added support for MPEG-4 encoding for the videos. I created a simple test Flex app to try and compare the video quality of the MP4 vs FLV encodings. However, I can't seem to get MP4 to work at all. According to the Flex documentation the only thing I need to do to use MP4 instead of FLV is prepend "mp4:" to the name of the stream when calling publish: Specify the stream name as a string with the prefix mp4: with or without the filename extension. The prefix indicates to the server that the file contains H.264-encoded video and AAC-encoded audio within the MPEG-4 Part 14 container format. When I try this nothing happens. I don't get any events raised on the client side, no exceptions thrown, and my logging on the server side doesn't show any streams starting. Here's the relevant code: // These are all defined and created within the class. private var nc:NetConnection; private var sharing:Boolean; private var pubStream:NetStream; private var format:String; private var streamName:String; private var camera:Camera; // called when the user clicks the start button private function startSharing():void { if (!nc.connected) { return; } if (sharing) { return; } if(pubStream == null) { pubStream = new NetStream(nc); pubStream.attachCamera(camera); } startPublish(); sharing = true; } private function startPublish():void { var name:String; if (this.format == "mp4") { name = "mp4:" + streamName; } else { name = streamName; } //pubStream.publish(name, "live"); pubStream.publish(name, "record"); }

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  • Eclipselink read complex oject model in an ordered way

    - by Raven
    Hi, I need to read a complex model in an ordered way with eclipselink. The order is mandantory because it is a huge database and I want to have an output of a small portion of the database in a jface tableview. Trying to reorder it in the loading/quering thread takes too long and ordering it in the LabelProvider blocks the UI thread too much time, so I thought if Eclipselink could be used that way, that the database will order it, it might give me the performance I need. Unfortunately the object model can not be changed :-( The model is something like: @SuppressWarnings("serial") @Entity public class Thing implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; @OneToMany(cascade=CascadeType.ALL) @PrivateOwned private List<Property> properties = new ArrayList<Property>(); ... // getter and setter following here } public class Property implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; @OneToOne private Item item; private String value; ... // getter and setter following here } public class Item implements Serializable { @Id @GeneratedValue(strategy = GenerationType.TABLE) private int id; private String name; .... // getter and setter following here } // Code end In the table view the y-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Thing m ORDER BY m.name ASC"); using the "name" attribute from the Thing objects as label. In the table view the x-axis is more or less created with the query Query q = em.createQuery("SELECT m FROM Item m ORDER BY m.name ASC"); using the "name" attribute from the Item objects as label. Each cell has the value Things.getProperties().get[x].getValue() Unfortunately the list "properties" is not ordered, so the combination of cell value and x-axis column number (x) is not necessarily correct. Therefore I need to order the list "properties" in the same way as I ordered the labeling of the x-axis. And exactly this is the thing I dont know how it is done. So querying for the Thing objects should return the list "properties" "ORDER BY name ASC" but of the "Item"s objects. My ideas are something like having a query with two JOINs. Joing Things with Property and with Item but somehow I was unable to get it to work yet. Thank you for your help and your ideas to solve this riddle.

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  • Updating with Related Entities - Entity Framework v4

    - by Vincent BOUZON
    Hi, I use Entity Framework V4 and i want to update Customer who have Visits. My code : EntityKey key; object originalItem; key = this._modelContainer.CreateEntityKey("Customers", customer); if (this._modelContainer.TryGetObjectByKey(key, out originalItem)) { this._modelContainer.ApplyCurrentValues(key.EntitySetName, customer); } this._modelContainer.SaveChanges(); It works for Scalar Property only. The customers.Visits collection is not updated. Best Regards :)

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  • How to capture user's keystroke times in openmoko?

    - by Berkay
    i will use this data for modelling the user, any good resource or tutorial will be appreciated.(this will be my first experience with openmoko) For example i'm trying to calculate: Key hold time: The time difference between pressing a key and releasing it Digraph time: The time difference between releasing one key and pressing the next one Error rate: The number of times backspace key is pressed. thanks (any kind of useful information for openmoko to help me this problem will be appreciated.)

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  • Strong Signing, and Updating A Referencing Assembly

    - by Alan
    Hi, I have two, third party assemblies: Foo.dll and ReferencesFoo.dll As noted, ReferencesFoo.dll is an assembly that has a reference to Foo.dll For my application, I need to resign these assemblies. I use ildasm/ilasm in combination along with a signing key to resign them, however, ReferencesFoo.dll still contains (in it's manifest?) the reference to the Foo.dll old public key and public key token. So, how do I sign both dll's with my key, and update the references in ReferencesFoo.dll without getting the source code and recompiling?

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  • Two way binding settings problem.

    - by Jamie
    Hi, I am having a problem using two way binding with a listpicker. I am able to set the value using c# but not in the SelectedItem=".." in xaml. The binding is returning the correct value (and is a value in the listpicker) as i have texted it by assigning the text to a textblock. When the page loads, the binding used on the listpicker causes a System.ArgumentOutOfRangeException The code i am using to set it is: // Update a setting value. If the setting does not exist, add the setting. public bool AddOrUpdateValue(string key, Object value) { bool valueChanged = false; try { // If new value is different, set the new value if (settingsStorage[key] != value) { settingsStorage[key] = value; valueChanged = true; } } catch (KeyNotFoundException) { settingsStorage.Add(key, value); valueChanged = true; } catch (ArgumentException) { settingsStorage.Add(key, value); valueChanged = true; } catch (Exception e) { Console.WriteLine("Exception occured whilst using IsolatedStorageSettings: " + e.ToString()); } return valueChanged; } // Get the current value of the setting, if not found, set the setting to default value. public valueType GetValueOrDefault<valueType>(string key, valueType defaultValue) { valueType value; try { value = (valueType)settingsStorage[key]; } catch (KeyNotFoundException) { value = defaultValue; } catch (ArgumentException) { value = defaultValue; } return value; } public string WeekBeginsSetting { get { return GetValueOrDefault<string>(WeekBeginsSettingKeyName, WeekBeginsSettingDefault); } set { AddOrUpdateValue(WeekBeginsSettingKeyName, value); Save(); } } And in the xaml: <toolkit:ListPicker x:Name="WeekStartDay" Header="Week begins on" SelectedItem="{Binding Source={StaticResource AppSettings}, Path=WeekBeginsSetting, Mode=TwoWay}"> <sys:String>monday</sys:String> <sys:String>sunday</sys:String> </toolkit:ListPicker> The StaticResource AppSettings is a resource from a seperate .cs file. <phone:PhoneApplicationPage.Resources> <local:ApplicationSettings x:Key="AppSettings"></local:ApplicationSettings> </phone:PhoneApplicationPage.Resources> Thanks in advance

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  • load Javascript object from file

    - by megapool020
    Hi there, I asked a question in this thread Stackoverflow, and it works perfect. So tnx to all the users who gave me a reply. But now I have a other question. I would like to have the object in a seperate file, so I only need to update the file in stead of the JS file (otherwise it will be very big). I'm using JQUERY. I now looks like this (with all the info in the JS file). IBANInfo is used to fill a selectbox var IBANInfo = { "ccAL":{ countryCode:"AL", countryName:"Albani&euml;", IBANlength:"28", bankFormCode:"0 8n 0 ", accountNum:"0 16 0 " }, "ccAD":{ countryCode:"AD", countryName:"Andorra", IBANlength:"24", bankFormCode:"0 4n 4n", accountNum:"0 12 0 " }, "ccBE":{ countryCode:"BE", countryName:"Belgi&euml;", IBANlength:"16", bankFormCode:"0 3n 0 ", accountNum:"0 7n 2n" } }; //---- then this function is used to build the selectList function createSelect(){ var selectList = ''; var key; selectList += "<option value=''>Kies een land</option>\n"; for (key in IBANInfo) { if (IBANInfo.hasOwnProperty(key)) { var countryInfo = IBANInfo[key]; selectList += "<option value='"+countryInfo.countryCode+"'>"+countryInfo.countryName+"</option>\n"; } } $('#selectBox').html(selectList); } I thought I could do it like this, but I get the message undefined in my selectbox. var IBANInfo = $.get('include/countryCodes.txt'); // also tried var IBANInfo = $.getJSON('include/countryCodes.txt'); //---- then this function is used to build the selectList function createSelect(){ var selectList = ''; var key; selectList += "<option value=''>Kies een land</option>\n"; for (key in IBANInfo) { if (IBANInfo.hasOwnProperty(key)) { var countryInfo = IBANInfo[key]; selectList += "<option value='"+countryInfo.countryCode+"'>"+countryInfo.countryName+"</option>\n"; } } $('#selectBox').html(selectList); } /* the countryCodes.txt file is like this: { "ccAL":{ countryCode:"AL", countryName:"Albani&euml;", IBANlength:"28", bankFormCode:"0 8n 0 ", accountNum:"0 16 0 " }, "ccAD":{ countryCode:"AD", countryName:"Andorra", IBANlength:"24", bankFormCode:"0 4n 4n", accountNum:"0 12 0 " }, "ccBE":{ countryCode:"BE", countryName:"Belgi&euml;", IBANlength:"16", bankFormCode:"0 3n 0 ", accountNum:"0 7n 2n" } } */ What am I doing wrong. Tnx in advance

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  • Can you change VS Win Forms designer code generation?

    - by Big Endian
    We implemented new standards, which call for our private members to have a leading underscore. Like so: private System.Windows.Forms.Label _label; Unfortunately VS will put out the default below when you drag a new label onto your form: private System.Windows.Forms.Label label1; Is there a way to change that to: private System.Windows.Forms.Label _label1; Cheers, Plamen

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  • Can I someone point to me what I did wrong? Trying to map VB to Java using JNA to access the library

    - by henry
    Original Working VB_Code Private Declare Function ConnectReader Lib "rfidhid.dll" () As Integer Private Declare Function DisconnectReader Lib "rfidhid.dll" () As Integer Private Declare Function SetAntenna Lib "rfidhid.dll" (ByVal mode As Integer) As Integer Private Declare Function Inventory Lib "rfidhid.dll" (ByRef tagdata As Byte, ByVal mode As Integer, ByRef taglen As Integer) As Integer Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim desc As String desc = "1. Click ""Connect"" to talk to reader." & vbCr & vbCr desc &= "2. Click ""RF On"" to wake up the TAG." & vbCr & vbCr desc &= "3. Click ""Read Tag"" to get tag PCEPC." lblDesc.Text = desc End Sub Private Sub cmdConnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdConnect.Click If cmdConnect.Text = "Connect" Then If ConnectReader() Then cmdConnect.Text = "Disconnect" Else MsgBox("Unable to connect to RFID Reader. Please check reader connection.") End If Else If DisconnectReader() Then cmdConnect.Text = "Connect" End If End If End Sub Private Sub cmdRF_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRF.Click If cmdRF.Text = "RF On" Then If SetAntenna(&HFF) Then cmdRF.Text = "RF Off" End If Else If SetAntenna(&H0) Then cmdRF.Text = "RF On" End If End If End Sub Private Sub cmdReadTag_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdReadTag.Click Dim tagdata(64) As Byte Dim taglen As Integer, cnt As Integer Dim pcepc As String pcepc = "" If Inventory(tagdata(0), 1, taglen) Then For cnt = 0 To taglen - 1 pcepc &= tagdata(cnt).ToString("X2") Next txtPCEPC.Text = pcepc Else txtPCEPC.Text = "ReadError" End If End Sub Java Code (Simplified) import com.sun.jna.Library; import com.sun.jna.Native; public class HelloWorld { public interface MyLibrary extends Library { public int ConnectReader(); public int SetAntenna (int mode); public int Inventory (byte tagdata, int mode, int taglen); } public static void main(String[] args) { MyLibrary lib = (MyLibrary) Native.loadLibrary("rfidhid", MyLibrary.class); System.out.println(lib.ConnectReader()); System.out.println(lib.SetAntenna(255)); byte[] tagdata = new byte[64]; int taglen = 0; int cnt; String pcepc; pcepc = ""; if (lib.Inventory(tagdata[0], 1, taglen) == 1) { for (cnt = 0; cnt < taglen; cnt++) pcepc += String.valueOf(tagdata[cnt]); } } } The error happens when lib.Inventory is run. lib.Inventory is used to get the tag from the RFID reader. If there is no tag, no error. The error code An unexpected error has been detected by Java Runtime Environment: EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0b1d41ab, pid=5744, tid=4584 Java VM: Java HotSpot(TM) Client VM (11.2-b01 mixed mode windows-x86) Problematic frame: C [rfidhid.dll+0x141ab] An error report file with more information is saved as: C:\eclipse\workspace\FelmiReader\hs_err_pid5744.log

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  • Ideas for multiplatform encrypted java mobile storage system

    - by Fernando Miguélez
    Objective I am currently designing the API for a multiplatform storage system that would offer same interface and capabilities accross following supported mobile Java Platforms: J2ME. Minimum configuration/profile CLDC 1.1/MIDP 2.0 with support for some necessary JSRs (JSR-75 for file storage). Android. No minimum platform version decided yet, but rather likely could be API level 7. Blackberry. It would use the same base source of J2ME but taking advantage of some advaced capabilities of the platform. No minimum configuration decided yet (maybe 4.6 because of 64 KB limitation for RMS on 4.5). Basically the API would sport three kind of stores: Files. These would allow standard directory/file manipulation (read/write through streams, create, mkdir, etc.). Preferences. It is a special store that handles properties accessed through keys (Similar to plain old java properties file but supporting some improvements such as different value data types such as SharedPreferences on Android platform) Local Message Queues. This store would offer basic message queue functionality. Considerations Inspired on JSR-75, all types of stores would be accessed in an uniform way by means of an URL following RFC 1738 conventions, but with custom defined prefixes (i.e. "file://" for files, "prefs://" for preferences or "queue://" for message queues). The address would refer to a virtual location that would be mapped to a physical storage object by each mobile platform implementation. Only files would allow hierarchical storage (folders) and access to external extorage memory cards (by means of a unit name, the same way as in JSR-75, but that would not change regardless of underlying platform). The other types would only support flat storage. The system should also support a secure version of all basic types. The user would indicate it by prefixing "s" to the URL (i.e. "sfile://" instead of "file://"). The API would only require one PIN (introduced only once) to access any kind of secure object types. Implementation issues For the implementation of both plaintext and encrypted stores, I would use the functionality available on the underlying platforms: Files. These are available on all platforms (J2ME only with JSR-75, but it is mandatory for our needs). The abstract File to actual File mapping is straight except for addressing issues. RMS. This type of store available on J2ME (and Blackberry) platforms is convenient for Preferences and maybe Message Queues (though depending on performance or size requirements these could be implemented by means of normal files). SharedPreferences. This type of storage, only available on Android, would match Preferences needs. SQLite databases. This could be used for message queues on Android (and maybe Blackberry). When it comes to encryption some requirements should be met: To ease the implementation it will be carried out on read/write operations basis on streams (for files), RMS Records, SharedPreferences key-value pairs, SQLite database columns. Every underlying storage object should use the same encryption key. Handling of encrypted stores should be the same as the unencrypted counterpart. The only difference (from the user point of view) accessing an encrypted store would be the addressing. The user PIN provides access to any secure storage object, but the change of it would not require to decrypt/re-encrypt all the encrypted data. Cryptographic capabilities of underlying platform should be used whenever it is possible, so we would use: J2ME: SATSA-CRYPTO if it is available (not mandatory) or lightweight BoncyCastle cryptographic framework for J2ME. Blackberry: RIM Cryptographic API or BouncyCastle Android: JCE with integraced cryptographic provider (BouncyCastle?) Doubts Having reached this point I was struck by some doubts about what solution would be more convenient, taking into account the limitation of the plataforms. These are some of my doubts: Encryption Algorithm for data. Would AES-128 be strong and fast enough? What alternatives for such scenario would you suggest? Encryption Mode. I have read about the weakness of ECB encryption versus CBC, but in this case the first would have the advantage of random access to blocks, which is interesting for seek functionality on files. What type of encryption mode would you choose instead? Is stream encryption suitable for this case? Key generation. There could be one key generated for each storage object (file, RMS RecordStore, etc.) or just use one for all the objects of the same type. The first seems "safer", though it would require some extra space on device. In your opinion what would the trade-offs of each? Key storage. For this case using a standard JKS (or PKCS#12) KeyStore file could be suited to store encryption keys, but I could also define a smaller structure (encryption-transformation / key data / checksum) that could be attached to each storage store (i.e. using addition files with the same name and special extension for plain files or embedded inside other types of objects such as RMS Record Stores). What approach would you prefer? And when it comes to using a standard KeyStore with multiple-key generation (given this is your preference), would it be better to use a record-store per storage object or just a global KeyStore keeping all keys (i.e. using the URL identifier of abstract storage object as alias)? Master key. The use of a master key seems obvious. This key should be protected by user PIN (introduced only once) and would allow access to the rest of encryption keys (they would be encrypted by means of this master key). Changing the PIN would only require to reencrypt this key and not all the encrypted data. Where would you keep it taking into account that if this got lost all data would be no further accesible? What further considerations should I take into account? Platform cryptography support. Do SATSA-CRYPTO-enabled J2ME phones really take advantage of some dedicated hardware acceleration (or other advantage I have not foreseen) and would this approach be prefered (whenever possible) over just BouncyCastle implementation? For the same reason is RIM Cryptographic API worth the license cost over BouncyCastle? Any comments, critics, further considerations or different approaches are welcome.

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  • design for a wrapper around command-line utilities

    - by hatchetman82
    im trying to come up with a design for a wrapper for use when invoking command line utilities in java. the trouble with runtime.exec() is that you need to keep reading from the process' out and err streams or it hangs when it fills its buffers. this has led me to the following design: public class CommandLineInterface { private final Thread stdOutThread; private final Thread stdErrThread; private final OutputStreamWriter stdin; private final History history; public CommandLineInterface(String command) throws IOException { this.history = new History(); this.history.addEntry(new HistoryEntry(EntryTypeEnum.INPUT, command)); Process process = Runtime.getRuntime().exec(command); stdin = new OutputStreamWriter(process.getOutputStream()); stdOutThread = new Thread(new Leech(process.getInputStream(), history, EntryTypeEnum.OUTPUT)); stdOutThread.setDaemon(true); stdOutThread.start(); stdErrThread = new Thread(new Leech(process.getErrorStream(), history, EntryTypeEnum.ERROR)); stdErrThread.setDaemon(true); stdErrThread.start(); } public void write(String input) throws IOException { this.history.addEntry(new HistoryEntry(EntryTypeEnum.INPUT, input)); stdin.write(input); stdin.write("\n"); stdin.flush(); } } public class Leech implements Runnable{ private final InputStream stream; private final History history; private final EntryTypeEnum type; private volatile boolean alive = true; public Leech(InputStream stream, History history, EntryTypeEnum type) { this.stream = stream; this.history = history; this.type = type; } public void run() { BufferedReader reader = new BufferedReader(new InputStreamReader(stream)); String line; try { while(alive) { line = reader.readLine(); if (line==null) break; history.addEntry(new HistoryEntry(type, line)); } } catch (Exception e) { e.printStackTrace(); } } } my issue is with the Leech class (used to "leech" the process' out and err streams and feed them into history - which acts like a log file) - on the one hand reading whole lines is nice and easy (and what im currently doing), but it means i miss the last line (usually the prompt line). i only see the prompt line when executing the next command (because there's no line break until that point). on the other hand, if i read characters myself, how can i tell when the process is "done" ? (either complete or waiting for input) has anyone tried something like waiting 100 millis since the last output from the process and declaring it "done" ? any better ideas on how i can implement a nice wrapper around things like runtime.exec("cmd.exe") ?

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  • Cannot instantiate abstract class or interface : problem while persisting

    - by sammy
    i have a class campaign that maintains a list of AdGroupInterfaces. im going to persist its implementation @Entity @Table(name = "campaigns") public class Campaign implements Serializable,Comparable<Object>,CampaignInterface { private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @OneToMany ( cascade = {CascadeType.ALL}, fetch = FetchType.EAGER, targetEntity=AdGroupInterface.class ) @org.hibernate.annotations.Cascade( value = org.hibernate.annotations.CascadeType.DELETE_ORPHAN ) @org.hibernate.annotations.IndexColumn(name = "CHOICE_POSITION") private List<AdGroupInterface> AdGroup; public Campaign() { super(); } public List<AdGroupInterface> getAdGroup() { return AdGroup; } public void setAdGroup(List<AdGroupInterface> adGroup) { AdGroup = adGroup; } public void set1AdGroup(AdGroupInterface adGroup) { if(AdGroup==null) AdGroup=new LinkedList<AdGroupInterface>(); AdGroup.add(adGroup); } } AdGroupInterface's implementation is AdGroups. when i add an adgroup to the list in campaign, campaign c; c.getAdGroupList().add(new AdGroups()), etc and save campaign it says"Cannot instantiate abstract class or interface :" AdGroupInterface its not recognizing the implementation just before persisting... Whereas Persisting adGroups separately works. when it is a member of another entity, it doesnt get persisted. import java.io.Serializable; import java.util.List; import javax.persistence.*; @Entity @DiscriminatorValue("1") @Table(name = "AdGroups") public class AdGroups implements Serializable,Comparable,AdGroupInterface{ /** * */ private static final long serialVersionUID = 1L; private Long Id; private String Name; private CampaignInterface Campaign; private MonetaryValue DefaultBid; public AdGroups(){ super(); } public AdGroups( String name, CampaignInterface campaign) { super(); this.Campaign=new Campaign(); Name = name; this.Campaign = campaign; DefaultBid = defaultBid; AdList=adList; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name="AdGroup_Id") public Long getId() { return Id; } public void setId(Long id) { Id = id; } @Column(name="AdGroup_Name") public String getName() { return Name; } public void setName(String name) { Name = name; } @ManyToOne @JoinColumn (name="Cam_ID", nullable = true,insertable = false) public CampaignInterface getCampaign() { return Campaign; } public void setCampaign(CampaignInterface campaign) { this.Campaign = campaign; } } what am i missing?? please look into it ...

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