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  • Java applet wont run

    - by Courtney
    I am trying to get a Java applet to run properly when linked to an HTML page in Dreamweaver CC. I'm new to all this so please bear with me here. First I saved this code to a .java file //Triangle.java import java.awt.*; import java.applet.Applet; public class Triangle extends Applet { public void paint (Graphics g){ int bottomX=80; int bottomY=200; int base=100; int height=100; g.drawLine(bottomX,bottomY,bottomX+base,bottomY); g.drawLine(bottomX+base,bottomY,bottomX+base/2,bottomY-height); g.drawLine(bottomX+base/2,bottomY-height, bottomX,bottomY); } } I then compiled it entering javac Triangle.java After that, I inserted it into a Dreamwever page using: <html> <applet code=Triangle.class width=400 height=400 > </applet> </html> Now when I try and open the page in Chrome I get an error reading: UnsupportedClassVersionError Triangle: Unsupported major.minor version 52.0 This, as I have read, is an issue with using two incompatible Java versions? In my Java Control Panel it says I am using version 1.8.0_20 and my JDK is jdk1.8.0_20. Does anyone see anything super obvious that I am doing wrong here?

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  • How do I configure a mail server for use with JavaMail?

    - by bobby
    I'm trying to work with the below code: import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import javax.mail.*; import javax.mail.internet.*; // important import javax.mail.event.*; // important import java.net.*; import java.util.*; public class servletmail extends HttpServlet { public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException { PrintWriter out=response.getWriter(); response.setContentType("text/html"); try { Properties props=new Properties(); props.put("mail.smtp.host","localhost"); // 'localhost' for testing Session session1 = Session.getDefaultInstance(props,null); String s1 = request.getParameter("text1"); //sender (from) String s2 = request.getParameter("text2"); String s3 = request.getParameter("text3"); String s4 = request.getParameter("area1"); Message message =new MimeMessage(session1); message.setFrom(new InternetAddress(s1)); message.setRecipients(Message.RecipientType.TO,InternetAddress.parse(s2,false)); message.setSubject(s3); message.setText(s4); Transport.send(message); out.println("mail has been sent"); } catch(Exception ex) { System.out.println("ERROR....."+ex); } } } I'm using mail.jar and activation.jar. But I can't understand how I should configure it with a mail server. Which mail server should I use? Will I be able to send an email using above code? What are the requirements a mail server? How should I configure it?

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  • java.lang.IllegalStateException: The content of the adapter has changed but ListView.... inspite of calling notifydatasetchanged()

    - by Mistaken
    What are the best practices to be followed to update the contents of a listactivty by a background thread (Async Task) ? 1) Am calling the notifyDataSetChanged() to update the adapter as soon as i manipulate the contents of the adapter but still my app force closes while the user scrolls or click on the list. Any pointers to prevent this would be very helpfull. Logcat: java.lang.IllegalStateException: The content of the adapter has changed but ListView did not receive a notification. 2) Where exaclty should i update contents of the listactivity ? inside the doInBackground() or onProgressUpdate()? 3) Am experiencing regular crashes when the user clicks the list item. So will disabling click events on the listactivty during the background operation solve the problem ? If so am not sure how to remove or set item click listeners dynamically to the listactivity. Please instruct me on the too. 4) I dont think blocking all ui interactions during the background async task execution is the only way to solve the problem. I know there is a simple way of doing this but need some help. Thanks in advance. This is my onCreate... protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fa); tvStatus=(TextView) findViewById(R.id.tvStatus); adapter = new SimpleAdapter( this, mostPopularList, R.layout.list_item, new String[] {"title","author","views","date"}, new int[] {R.id.textView1,R.id.textView2,R.id.textView4,R.id.textView3}); //populateList(); setListAdapter(adapter); } My async task... private class LongOperation extends AsyncTask<String, Void, String> { @Override protected String doInBackground(String... params) { // code for adding new listactivty items } @Override protected void onPostExecute(String networkStatus) { adapter.notifyDataSetChanged(); } @Override protected void onPreExecute() { } @Override protected void onProgressUpdate(Void... values) { } }

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  • How to bind Assisted Injected class to interface?

    - by eric2323223
    Here is the problem I met: Class SimpleCommand implements Executable{ private final ConfigManager config; private String name; @Inject public SimpleCommand(ConfigManager config, @Assisted String name){ this.config = config; this.name = name; } } Class MyModule extends AbstractModule{ @Override protected void configure() { bind(CommandFactory.class).toProvider(FactoryProvider.newFactory(CommandFactory.class, SimpleCommand.class)); bind(Executable.class).to(SimpleCommand.class); } } When I try to get instance of SimpleCommand using: Guice.createInjector(new MyModule()).getInstance(CommandFactory.class).create("sample command"); I got this error: 1) No implementation for java.lang.String annotated with @com.google.inject.assistedinject.Assisted(value=) was bound. while locating java.lang.String annotated with @com.google.inject.assistedinject.Assisted(value=) for parameter 2 at model.Command.<init>(SimpleCommand.java:58) at module.MyModule.configure(MyModule.java:34) So my problem is how can I bind SimpleCommand to Executable when SimpleCommand has Assisted Injected parameter? Here is the CommandFactory and its implementation: public interface CommandFactory{ public Command create(String name); } public class GuiceCommandFactory implements CommandFactory{ private Provider<ConfigManager> configManager ; @Inject public GuiceCommandFactory(Provider<ConfigManager> configManager){ this.configManager = configManager; } public Command create(String cmd){ return new Command(configManager.get(), cmd); } }

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  • Usage of setInfoClass() on DirectoryIterator vs on RecursiveDirectoryIterator

    - by Gordon
    I've ran into an inconsistent behavior when using setInfoClass to set a custom SplFileInfo class to a DirectoryIterator versus setting it to a RecursiveIterator. The method description states: Use this method to set a custom class which will be used when getFileInfo and getPathInfo are called. The class name passed to this method must be derived from SplFileInfo. Consider this custom SplFileInfo class A extends SplFileInfo { public function test() { printf("I am of class %s\n", __CLASS__); } } and my iterators $iterator = new DirectoryIterator('.'); and $iterator = new RecursiveDirectoryIterator('.'); Now I'd expect those two to behave the same when I do $iterator->setInfoClass('A'); foreach($iterator as $file) { $file->test(); } and output 'I am of A' for each $file encountered and in fact, the RecursiveDirectoryIterator will do that. But the DirectoryIterator will raise Fatal error: Call to undefined method DirectoryIterator::test() so apparently the InfoClass does not get applied when iterating over the files. At least not directly, because when I change the code in the foreach loop to $file->getPathInfo()->test(); it will work for the DirectoryIterator. But then the RecursiveDirectoryIterator will raise Fatal error: Call to undefined method SplFileInfo::test() Like I said, I'd expect those two to behave the same, but apparently getFileInfo and getPathInfo don't get called in the DirectoryIterator, which I consider a bug. So if there is any Iterator experts out there, please help me understand this. Thanks.

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  • Zend Framework: How do I modify/format the form view generated with Zend_Dojo_Form elements

    - by pinardelrio
    I have created a form: <?php class Application_Form_Issue extends Zend_Dojo_Form { public function init() { $this->setName('issue'); $this->setMethod('post'); $id = new Zend_Form_Element_Hidden('id'); $id->addFilter('Int'); $date_recvd = new Zend_Dojo_Form_Element_DateTextBox('date_recvd'); $date_recvd->setLabel('Date Received') //->setRequired(true) /*->addValidator('NotEmpty'); */; More Form elements ... To view this form my view script is: <?php echo $this->form; ?> This all works just fine, with fully functional dojo form elements (datepicker, timepicker, etc) and successfully saving the data. However, now, I want to format the form that is generated with css. Such as grouping some elements and floating left or right, making some input text fields wider/narrower, etc. How? I realize I can modify the view script but it seems like that defeats the purpose of using Zend_Dojo_Form or Zend_Form. Is that a correct assumption?

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  • Limiting Row Selection in JTable

    - by Pat
    Is there an easy way to limit the total selection of rows in a JTable? I mean I'd like to allow the user to use shift and ctrl to select a maximum of X rows. If he clicks again on a row it would cancel out all the selections. Sort of how it currently behaves, but while limiting the total amount of selected rows. Here's my current implementation, I'm kind of clueless on how to limit the selection graphically. public class RoomsListView extends AbstractViewPanel { public RoomsListView(DefaultController controller) { this.controller = controller; initUI(); } private void initUI() { tableT = new JTable(RoomsModel.getInstance()); sorter = new TableRowSorter<RoomsModel>(RoomsModel.getInstance()); tableT.setRowSorter(sorter); tableT.setPreferredScrollableViewportSize(new Dimension(CUSTOM_TABLE_WIDTH, CUSTOM_TABLE_HEIGHT)); tableT.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { rowClickedPerformed(e); } }); } private void rowClickedPerformed(MouseEvent e) { } public void modelPropertyChange(PropertyChangeEvent evt) { } public JTable getTable() { return tableT; } private final int CUSTOM_TABLE_WIDTH = -1; private final int CUSTOM_TABLE_HEIGHT = 150; private JTable tableT; private DefaultController controller; private TableRowSorter<RoomsModel> sorter; }

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  • zend form check record no exists in database

    - by Yafa Su
    I have a form that check if email exists in the database within 2 tables. I'm using Zend_Validate_Db_NoRecordExists for both validate, but it only check the second one. Any idea why it's not working? class Application_Form_ReferUser extends Zend_Form { public $email, $freeDownload, $buyNow; public function init() { $this->setName('referUser'); $EmailExists = new Zend_Validate_Db_NoRecordExists( array( 'table' => 'referrals', 'field' => 'email' ) ); $EmailExists2 = new Zend_Validate_Db_NoRecordExists( array( 'table' => 'users', 'field' => 'email' ) ); $EmailExists->setMessage('This e-mail is already taken'); $EmailExists2->setMessage('This e-mail is already taken'); $this->email = $this->createElement('text', 'email') ->setLabel('Email') ->addValidator($EmailExists) ->addValidator($EmailExists2) ->addValidator('EmailAddress') ->setRequired(true); $this->freeDownload = $this->createElement('button', 'btn_free_download') ->setLabel('Free Download') ->setAttrib('type', 'submit'); $this->buyNow = $this->createElement('button', 'btn_buy_now') ->setLabel('Buy Now') ->setAttrib('type', 'submit'); $this->addElements(array($this->email, $this->freeDownload, $this->buyNow)); $elementDecorators = array( 'ViewHelper' ); $this->setElementDecorators($elementDecorators); } }

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  • What is wrong with this Asynchronus task?

    - by bluebrain
    the method onPostExecute simply was not executed, I have seen 16 at LogCat but I can not see 16 in LogCAT. I tried to debug it, it seemed that it goes to the first line of the class (package line) after return statement. private class Client extends AsyncTask<Integer, Void, Integer> { protected Integer doInBackground(Integer... params) { Log.e(TAG,10+""); try { socket = new Socket(target, port); Log.e(TAG,11+""); oos = new ObjectOutputStream(socket.getOutputStream()); Log.e(TAG,14+""); ois = new ObjectInputStream(socket.getInputStream()); Log.e(TAG,15+""); } catch (UnknownHostException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } Log.e(TAG,16+""); return 1; } protected void onPostExecute(Integer result) { Log.e(TAG,13+""); try { Log.e(TAG,12+""); oos.writeUTF(key); Log.e(TAG,13+""); if (ois.readInt() == OKAY) { isConnected = true; Log.e(TAG,14+""); }else{ Log.e(TAG,15+""); isConnected = false; } } catch (IOException e) { e.printStackTrace(); isClosed = true; } } }

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  • setImageViewResource Sometimes loads image and sometimes it doesn't.

    - by Niv
    Hi All, I'm writing a simple widget which has an imageview widget that is supposed to load an image dynamically. To do this, I'm starting a service in the onUpdate method of the service. I validated that the service is running, however, the image is loaded only once every 10 times. Here is the code: (In the Original extends AppWidgetProvider) @Override public void onUpdate(Context context, AppWidgetManager appWidgetManager, int[] appWidgetIds) { Log.d(LOG_TAG, "onUpdate(): Starting Service..1"); context.startService(new Intent(context, UpdateService.class)); } (The service:) @Override public void onStart(Intent intent, int startId) { Log.d(LOG_TAG, "(OnStart) In On Start..!"); AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(this); int[] appWidgetIds = appWidgetManager.getAppWidgetIds(new ComponentName(this, Original.class)); for (int appWidgetId : appWidgetIds) { RemoteViews remoteView = new RemoteViews(this.getPackageName(), R.layout.widget); remoteView.setImageViewResource(R.id.widgetImage, R.drawable.let02); remoteView.setTextViewText(R.id.widget_textview_month, "aaa"); Log.d(LOG_TAG, "(OnUpdate) Set All Fields!"); appWidgetManager.updateAppWidget(appWidgetId, remoteView); } //super.onStart(intent, startId); return; }

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  • android: ending activity from tab

    - by Jin
    I have 3 classes, let's call them 1, 2, and 3. Class 1 extends TabActivity and organizes the whole tab thing, Class 2 and 3 are just two separate tabs each with some lines of text. I call Class 1 from another activity using startActivityForResult. I then added an optionsMenu in class 2, and when user clicks the optionMenu, the following code is carried out: @Override public boolean onMenuItemSelected(int featureId, MenuItem item) { Intent i = new Intent(); switch(item.getItemId()) { case Result.NEXT_ID: i.putExtra(Result.PAGE_REQUEST, NEXT); setResult(RESULT_OK, i); finish(); break; case Result.PREV_ID: i.putExtra(Result.PAGE_REQUEST, PREV); setResult(RESULT_OK, i); finish(); } return super.onMenuItemSelected(featureId, item); } In my parent class (the class that called 1 to begin with), in its onActivityResult function, I want to get the data from the extras. However, the intent is always null, and I can't figure out why. When I call finish() on class 2, is it calling some other function in class 1? Do I have to transfer the intent data somehow?

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  • Calling an Overridden Method from a Parent-Class Constructor

    - by Vaibhav Bajpai
    I tried calling an overridden method from a constructor of a parent class and noticed different behavior across languages. C++ - echoes A.foo() class A{ public: A(){foo();} virtual void foo(){cout<<"A.foo()";} }; class B : public A{ public: B(){} void foo(){cout<<"B.foo()";} }; int main(){ B *b = new B(); } Java - echoes B.foo() class A{ public A(){foo();} public void foo(){System.out.println("A.foo()");} } class B extends A{ public void foo(){System.out.println("B.foo()");} } class Demo{ public static void main(String args[]){ B b = new B(); } } C# - echoes B.foo() class A{ public A(){foo();} public virtual void foo(){Console.WriteLine("A.foo()");} } class B : A{ public override void foo(){Console.WriteLine("B.foo()");} } class MainClass { public static void Main (string[] args) { B b = new B(); } } I realize that in C++ objects are created from top-most parent going down the hierarchy, so when the constructor calls the overridden method, B does not even exist, so it calls the A' version of the method. However, I am not sure why I am getting different behavior in Java and C#.

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  • CodeIgniter URI routing (dynamic, multilingual)

    - by koteko
    I'm trying to redirect all routs to one main controller. Here is my routes.php $route['default_controller'] = "main"; $route['scaffolding_trigger'] = ""; //$route['(\w{2})/(.*)'] = '$2'; //$route['(\w{2})'] = $route['default_controller']; $route['(en|ge)/(:any)'] = $route['default_controller']."/index/$1"; $route['(:any)'] = $route['default_controller']."/index/$1"; I need language id to be passed with every link (like: http://site.com/en/hello-world) Here is my main controller: class Main extends Controller { function __construct() { parent::Controller(); } function index($page_type=false, $param=false) { die($page_type.' | '.$param.'| Aaa!'); } } I want to check if predefined file type exists (like: http://site.com/en/archive/05-06-2010 - here predefined type would be archive) then do something. If not then search in the database for slug. If not found then go to 404. The problem is that I can't get index function parameters ($page_type, $param). Thanks for help.

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  • Could this be considered a well-written class (am I using OOP correctly)?

    - by Ben Dauphinee
    I have been learning OOP principals on my own for a while, and taken a few cracks at writing classes. What I really need to know now is if I am actually using what I have learned correctly, or if I could improve as far as OOP is concerned. I have chopped a massive portion of code out of a class that I have been working on for a while now, and pasted it here. To all you skilled and knowledgeable programmers here I ask: Am I doing it wrong? class acl extends genericAPI{ // -- Copied from genericAPI class protected final function sanityCheck($what, $check, $vars){ switch($check){ case 'set': if(isset($vars[$what])){return(1);}else{return(0);} break; } } // --------------------------------- protected $db = null; protected $dataQuery = null; public function __construct(Zend_Db_Adapter_Abstract $db, $config = array()){ $this->db = $db; if(!empty($config)){$this->config = $config;} } protected function _buildQuery($selectType = null, $vars = array()){ // Removed switches for simplicity sake $this->dataQuery = $this->db->select( )->from( $this->config['table_users'], array('tf' => '(CASE WHEN count(*) > 0 THEN 1 ELSE 0 END)') )->where( $this->config['uidcol'] . ' = ?', $vars['uid'] ); } protected function _sanityRun_acl($sanitycheck, &$vars){ switch($sanitycheck){ case 'uid_set': if(!$this->sanityCheck('uid', 'set', $vars)){ throw new Exception(ERR_ACL_NOUID); } $vars['uid'] = settype($vars['uid'], 'integer'); break; } } private function user($action = null, $vars = array()){ switch($action){ case 'exists': $this->_sanityRun_acl('uid_set', $vars); $this->_buildQuery('user_exists_idcheck', $vars); return($this->db->fetchOne($this->dataQuery->__toString())); break; } } public function user_exists($uid){ return($this->user('exists', array('uid' => $uid))); } } $return = $acl_test->user_exists(1);

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  • ListView exception for Images + Text

    - by drozzy
    I am trying to create a simple Icon+Text ListView but it does not work. I am using 2.1 Android SDK. My main class is very small slightly modified from the tutorial: public class Stuffs extends ListActivity { static final String[] COUNTRIES = new String[] {"A", "B","C"}; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item, R.id.title, COUNTRIES)); } } and my list_item.xml file is this: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation = "horizontal"> <ImageView android:id = "@+id/icon" android:src="@drawable/icon" /> <TextView android:id = "@+id/title" android:padding="10dp" android:textSize="16sp" > </TextView> </LinearLayout> I have also created a "drawable" directory in my res directory and copied a "icon.png" into it. But any time I try to run this the application hangs up unexpected in my android emulator. Am I missing something?

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  • Why is no encoding set in reponse by tomcat? How can I deal with it?

    - by Dishayloo
    I had recently a problem with encoding of websites generated by servlet, that occured if the servlets were deployed under tomcat, but not under jetty. I did a little bit of research about it and simplified the problem to the following servlet: public class TestServlet extends HttpServlet implements Servlet { @Override public void service(HttpServletRequest request, HttpServletResponse response) throws IOException { response.setContentType("text/plain"); Writer output = response.getWriter(); output.write("öäüÖÄÜß"); output.flush(); output.close(); } } If I deploy this under Jetty and direct the browser to it, it returns the expected result. The data is returned as ISO-8859-1 and if I take a look into the headers, then Jetty returns: Content-Type: text/plain; charset=iso-8859-1 The browser detects the encoding from this header. If I deploy the same servlet in a tomcat, the browser shows up strange characters. But Tomcat also returns the data as ISO-8859-1, the difference is, that no header tells about it. So the browser has to guess the encoding, and that goes wrong. My question is, is that behaviour of tomcat correct or a bug? And if it is correct, how can I avoid this problem? Sure, I can always add response.setCharacterEncoding("UTF-8"); to the servlet, but that means I set a fixed encoding, that the browser might or might not understand. The problem is more relevant, if no browser but another service accesses the servlet. So how I should deal with the problem in the most flexible way?

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  • How to access individual items in Android GridView?

    - by source.rar
    Hi, I'm trying to create a game with a 9x9 grid with GridView. Each item in the grid is a TextView. I am able to set the initial values of each item in the grid within the getView() method to "0", however I want to change the value of each grid individually after this but have been unable to do so. I tried adding an update() function in my extended GridAdapter class that takes a position and a number to update at that position but this doesnt seem to be working. public void update(int position, int number) { TextView cell; cell = (TextView) getItem(position); if (cell != null) { cell.setText(Integer.toString(number)); } } Doe anyone know how this can be achieved? Here's the whole GridAdapter class in case require, public class SudokuGridAdapter extends BaseAdapter { private Context myContext; private TextView[] myCells; public SudokuGridAdapter(Context c) { myContext = c; myCells = new TextView[9*9]; } @Override public int getCount() { // TODO Auto-generated method stub return 9*9; } @Override public Object getItem(int position) { return myCells[position]; } @Override public long getItemId(int position) { // TODO Auto-generated method stub return 0; } @Override public View getView(int position, View convertView, ViewGroup parent) { TextView cell; if (myCells[position] == null) { cell = myCells[position] = new TextView(myContext); cell.setText("0"); } else { cell = myCells[position]; } return cell; } public void update(int position, int number) { TextView cell; cell = (TextView) getItem(position); if (cell != null) { cell.setText(Integer.toString(number)); } } }

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  • Memory increases with Java UDP Server

    - by Trevor
    I have a simple UDP server that creates a new thread for processing incoming data. While testing it by sending about 100 packets/second I notice that it's memory usage continues to increase. Is there any leak evident from my code below? Here is the code for the server. public class UDPServer { public static void main(String[] args) { UDPServer server = new UDPServer(15001); server.start(); } private int port; public UDPServer(int port) { this.port = port; } public void start() { try { DatagramSocket ss = new DatagramSocket(this.port); while(true) { byte[] data = new byte[1412]; DatagramPacket receivePacket = new DatagramPacket(data, data.length); ss.receive(receivePacket); new DataHandler(receivePacket.getData()).start(); } } catch (IOException e) { e.printStackTrace(); } } } Here is the code for the new thread that processes the data. For now, the run() method doesn't do anything. public class DataHandler extends Thread { private byte[] data; public DataHandler(byte[] data) { this.data = data; } @Override public void run() { System.out.println("run"); } }

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  • Java Swing: How to add a CellRenderer for displaying a Date?

    - by HansDampf
    I have a Table: public class AppointmentTableModel extends AbstractTableModel { private int columns; private int rows; ArrayList<Appointment> appointments;... So each row of the table contains one Appointment. public class Appointment { private Date date; private Sample sample; private String comment; private ArrayList<Action> history; public Appointment(Date date, Sample sample, String comment) { this.date = date; this.sample = sample; this.comment = comment; this.history = new ArrayList<Action>(); } public Object getByColumn(int columnIndex) { switch (columnIndex) { case 0: return date;//Date: dd:mm:yyyy case 1: return date;//Time mm:hh case 2: return sample;//sample.getID() int (sampleID) case 3: return sample;//sample.getNumber string (telephone number) case 4: return sample;//sample.getName string (name of the person) case 5: return history;//newst element in history as a string case 6: return comment;//comment as string } return null; I added in comments what this one is going to mean. How would I create CellRenderers to display it like this. table.getColumnModel().getColumn(1).setCellRenderer(new DateRenderer()); I also want to add the whole row to be painted in red when the date is later then the current date. And then another column that holds a JButton to open up another screen with the corresponding Appointment as parameter.

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  • Adding functions to Java class libraries

    - by Eric
    I'm using a Java class library that is in many ways incomplete: there are many classes that I feel ought to have additional member functions built in. However, I am unsure of the best practice of adding these member functions. Lets call the insufficient base class A. class A { public A(/*long arbitrary arguments*/) { //... } public A(/*long even more arbitrary arguments*/) { //... } public int func() { return 1; } } Ideally, I would like to add a function to A. However, I can't do that. My choice is between: class B extends A { //Implement ALL of A's constructors here public int reallyUsefulFunction() { return func()+1; } } and class AddedFuncs { public int reallyUsefulFunction(A a) { return a.func()+1; } } The way I see it, they both have advantages and disadvantages. The first choice gives a cleaner syntax than the second, and is more logical, but has problems: Let's say I have a third class, C, within the class library. class C { public A func() { return new A(/*...*/); } } As I see it, there is no easy way of doing this: C c; int useful = c.func().reallyUsefulFunction(); as the type returned by C.func() is an A, not a B, and you can't down-cast. So what is the best way of adding a member function to a read-only library class?

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  • How i can fix the increasing order summation code?

    - by user2971559
    I want from the java to reads all numbers from the user as long as the number entered by user is bigger than the previous number. But i could write it for only positive numbers. How i can fix code below if all numbers included. If it is possible please write the solution for beginners because its my first year in computer science in college and I haven't learn a lot yet. import acm.program.*; public class IncreasingOrder extends ConsoleProgram { public void run() { int previousNumber = 0; int total = 0; int count = 0; while(true) { int n = readInt("Enter > "); if (n <= previousNumber) break; total += n; count++; previousNumber = n; } println("You have entered " + count + " numbers in increasing order."); println("Sum of these " + count + " numbers is " + total + "."); } }

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  • Android Notepadv1 Tutorial - Persistent mNoteNumber?

    - by Chris L.
    So I did the Notepadv1 tutorial. It worked great. No problems. I would however like some explanation on why the mNoteNumber remembers the last number of the item I created. So the class starts as follows: public class Notepadv1 extends ListActivity { private int mNoteNumber = 1; That's fine, I understand that. The only other time the mNoteNumber variable is used is when you add an item it creates a note with that number and then increments it to the next number as follows: private void createNote() { String noteName = "Note " + mNoteNumber++; Those are the only two references to the variable mNoteNumber. When I press the Home button and then reopen the app, I add a new note but instead of adding a second "Note 1" it remembers that the last note I added as "Note 3" so it makes "Note 4". So I don't get it. Does Java/Android remember the last state of variables? If anyone could give me some explanation that would be great THANKS!

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  • How can I achieve this kind of relationship (inheritance, composition, something else)?

    - by Tim
    I would like to set up a foundation of classes for an application, two of which are person and student. A person may or may not be a student and a student is always a person. The fact that a student “is a” person led me to try inheritance, but I can't see how to make it work in the case where I have a DAO that returns an instance of person and I then want to determine if that person is a student and call student related methods for it. class Person { private $_firstName; public function isStudent() { // figure out if this person is a student return true; // (or false) } } class Student extends Person { private $_gpa; public function getGpa() { // do something to retrieve this student's gpa return 4.0; // (or whatever it is) } } class SomeDaoThatReturnsPersonInstances { public function find() { return new Person(); } } $myPerson = SomeDaoThatReturnsPersonInstances::find(); if($myPerson->isStudent()) { echo 'My person\'s GPA is: ', $myPerson->getGpa(); } This obviously doesn't work, but what is the best way to achieve this effect? Composition doesn't sond right in my mind because a person does not “have a” student. I'm not looking for a solution necessarily but maybe just a term or phrase to search for. Since I'm not really sure what to call what I'm trying to do, I haven't had much luck. Thank you!

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  • Blackberry UI tool bar : fields alignment

    - by Galaxy
    i am developing custom toolbar manager, but i want to adjust the fields alignment to be centered not aligned to the left , any advice below is the code of toolbar package galaxy.bb.ui.container; import net.rim.device.api.ui.Color; import net.rim.device.api.ui.Graphics; import net.rim.device.api.ui.XYEdges; import net.rim.device.api.ui.container.HorizontalFieldManager; import net.rim.device.api.ui.decor.Background; import net.rim.device.api.ui.decor.BackgroundFactory; import net.rim.device.api.ui.decor.Border; import net.rim.device.api.ui.decor.BorderFactory; public class ToolBarManager extends HorizontalFieldManager { private int bgColor = Color.BLACK; private int borderColor = Color.WHITE; private int borderStyle= Border.STYLE_FILLED; public ToolBarManager(){ super(USE_ALL_WIDTH); } public ToolBarManager(int bgColor) { super(USE_ALL_WIDTH); this.bgColor = bgColor; } public ToolBarManager(int bgColor, int borderStyle) { super(USE_ALL_WIDTH); this.bgColor = bgColor; this.borderStyle = borderStyle; } public int getBgColor() { return bgColor; } public void setBgColor(int bgColor) { this.bgColor = bgColor; } public int getBorderColor() { return borderColor; } public void setBorderColor(int borderColor) { this.borderColor = borderColor; } public int getBorderStyle() { return borderStyle; } public void setBorderStyle(int borderStyle) { this.borderStyle = borderStyle; } protected void paint(Graphics graphics) { super.paint(graphics); XYEdges padding = new XYEdges(5, 5, 5, 5); Border roundedBorder = BorderFactory.createRoundedBorder(padding, borderColor, borderStyle); this.setBorder(roundedBorder); Background bg = BackgroundFactory.createSolidBackground(bgColor); this.setBackground(bg); } }

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  • showDialog in Activity not displaying dialog

    - by Mohit Deshpande
    Here is my code: public class TasksList extends ListActivity { ... private static final int COLUMNS_DIALOG = 7; private static final int ORDER_DIALOG = 8; ... /** * @see android.app.Activity#onCreateDialog(int) */ @Override protected Dialog onCreateDialog(int id) { Dialog dialog; final String[] columns; Cursor c = managedQuery(Tasks.CONTENT_URI, null, null, null, null); columns = c.getColumnNames(); final String[] order = { "Ascending", "Descending" }; switch (id) { case COLUMNS_DIALOG: AlertDialog.Builder columnDialog = new AlertDialog.Builder(this); columnDialog.setSingleChoiceItems(columns, -1, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { bundle.putString("column", columns[which]); } }); dialog = columnDialog.create(); case ORDER_DIALOG: AlertDialog.Builder orderDialog = new AlertDialog.Builder(this); orderDialog.setSingleChoiceItems(order, -1, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { String orderS; if (order[which].equalsIgnoreCase("Ascending")) orderS = "ASC"; else orderS = "DESC"; bundle.putString("order", orderS); } }); dialog = orderDialog.create(); default: dialog = null; } return dialog; } /** * @see android.app.Activity#onOptionsItemSelected(android.view.MenuItem) */ @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case SORT_MENU: showDialog(COLUMNS_DIALOG); showDialog(ORDER_DIALOG); String orderBy = bundle.getString("column") + bundle.getString("order"); Cursor tasks = managedQuery(Tasks.CONTENT_URI, projection, null, null, orderBy); adapter = new TasksAdapter(this, tasks); getListView().setAdapter(adapter); break; case FILTER_MENU: break; } return false; } The showDialog doesn't display the dialog. I used the Debugger and it does executes these statements, but the dialog doesn't show. }

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