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  • Multiple Exception Handling in one if statement [closed]

    - by JA3N
    I am having trouble with throwing and catching exceptions. Here is the code for assignSeat(), assignSeat is called in a try block in another class. void assignSeat(String passengerName, int x, int y) throws SeatOccupiedException, InvalidPassengerNameException { Seat tSeat = airplane.getSeat(x,y); if (tSeat!=null) { if (passengerName.isEmpty() || !passengerName.matches("[a-zA-Z]+")) { throw new InvalidPassengerNameException(); } //excluded else if else if (foundPassenger(passengerName)) { airplane.seatList.get(airplane.seatNumber(passengerName)).unOccupy(); tSeat.occupy(); for (int i = 0; i<passengers.size();i++) if (passengers.get(i).getName().equals(passengerName)) passengers.get(i).changeSeat(tSeat.getSeatName()); } else if (!tSeat.occupied) { tSeat.occupy(); addPassenger(passengerName, tSeat.getSeatName()); } else if (tSeat.occupied) { throw new SeatOccupiedException(); } } and here is the code that calls assignSeat() and is in another class (I won't copy the whole class to make it look clearer) if (afComp.currentAF != null) { try { afComp.currentAF.assignSeat(nameField.getText(), x, y); //<-Problem here, "Unhandled exception type SeatOccupiedException" } catch (SeatOccupiedException exception) //<-Problem here, "Unreachable catch block, This exception is never thrown from the try statement body" { } catch(InvalidPassengerNameException exception) //<-No problems. { } } Whats wrong with the try block? why won't it throw the SeatOccupiedException? Exception classes: SeatOccupied: package a2; public class SeatOccupiedException extends Exception { public SeatOccupiedException(){} } InvalidPassengerName: package a2; public class InvalidPassengerNameException extends Exception { public InvalidPassengerNameException() {} } Every class I have is in package a2 imports for class that calls assignSeat package a2; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import java.awt.event.MouseEvent; import java.awt.BorderLayout; import javax.swing.*; import javax.swing.event.*; imports for class that has assignSeat package a2; import java.util.ArrayList;

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  • Codeigniter .htaccess not working in subdirectory

    - by xzdead
    I have this codeingniter project structure webRoot | |/application | | | |/controllers | | | |/admin | |/public | | | |/admin | | | | | |/css | | |/img | |/css | |/img And this is my .htacess file, located in /public. I use this in every local project running xampp: <IfModule mod_rewrite.c> RewriteEngine On RewriteBase / RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.*)$ index.php/$1 [L] </IfModule> <IfModule !mod_rewrite.c> # If we don't have mod_rewrite installed, all 404's # can be sent to index.php, and everything works as normal. # Submitted by: ElliotHaughin ErrorDocument 404 /index.php </IfModule> It works fine in localhost, but doesn't work in a dreamhost server. I always get "no input file specified". So after searching the web and trying lots of combinations, the best I got is this .htaccess file: Options +FollowSymLinks RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] With this one, if I go to http://development.mydomain.com - I see the codeigniter welcome page But if I go to: http://development.mydomain.com/admin - I see the directory listing of /public/admin and doesn't execute the controller in /application/controllers/admin Again, if I go to: http://development.mydomain.com/admin/admin - I see the private area, it executes the controller and goes to the default controller defined in routes, "dashboard" This works fine too: http://development.mydomain.com/admin/dashboard I have set in my config file: $config['index_page'] = ''; $config['base_url'] = ''; $config['uri_protocol'] = 'AUTO'; I think that whatever is wrong in my .htaccess is causing other path issues I have with my project. Any help would be great. Thanks to all in advance EDIT: I removed this line: RewriteCond %{REQUEST_FILENAME} !-d because admin directory exists, that's why I see the public directory listing. But now I see the codeigniter welcome page when I go to http://development.mydomain.com/admin So now my .htaccess file looks like: Options +FollowSymLinks RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] #RewriteRule ^(.*)$ /index.php?/$1 [L] I also tried with the commented RewriteRule but I get the same result.

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  • Where do you put your dependencies?

    - by The All Foo
    If I use the dependency injection pattern to remove dependencies they end up some where else. For example, Snippet 1, or what I call Object Maker. I mean you have to instantiate your objects somewhere...so when you move dependency out of one object, you end up putting it another one. I see that this consolidates all my dependencies into one object. Is that the point, to reduce your dependencies so that they all reside in a single ( as close to as possible ) location? Snippet 1 - Object Maker <?php class ObjectMaker { public function makeSignUp() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignUpObject = new ControlSignUp(); $SignUpObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignUpObject; } public function makeSignIn() { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); $SignInObject = new ControlSignIn(); $SignInObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $SignInObject; } public function makeTweet( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $TweetObject = new ControlTweet(); $TweetObject->setObjects($DatabaseObject, $TextObject, $MessageObject); return $TweetObject; } public function makeBookmark( $DatabaseObject = NULL, $TextObject = NULL, $MessageObject = NULL ) { if( $DatabaseObject == 'small' ) { $DatabaseObject = new Database(); } else if( $DatabaseObject == NULL ) { $DatabaseObject = new Database(); $TextObject = new Text(); $MessageObject = new Message(); } $BookmarkObject = new ControlBookmark(); $BookmarkObject->setObjects($DatabaseObject,$TextObject,$MessageObject); return $BookmarkObject; } }

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  • Changing brightness in bufferedImage with DataBufferInt

    - by user2958025
    I must read some image and then I have to change brightness and contrast of this image I create main class and constructor where are panels, sliders and other stuff, I added changeListener to slider to take current value. My imagePanel is new Object of that class: public class Obrazek extends JPanel{ public static BufferedImage img = null; public Obrazek() { super(); try { img = ImageIO.read(new File("D:\\ja.jpg")); } catch (IOException e) {} } @Override public void paint(Graphics g) { g.drawImage(img, 0, 0, null); } } This is my load button private void przyciskWczytaj(java.awt.event.ActionEvent evt) { int odpowiedz = jFileChooser1.showOpenDialog(this); if (odpowiedz == jFileChooser1.APPROVE_OPTION) { File file = jFileChooser1.getSelectedFile(); try { BufferedImage im = ImageIO.read(new File(file.getAbsolutePath())); Obrazek.img = im; } catch (IOException ex) { System.out.println("Error"); } } } And now I want to create class where I will change that brightness. I have to use but I don't know how to use that thing: BufferedImage(256, 256, Bufferedmage.TYPE_INT_RGB) and to get each pixel of image I need to do something like: int rgb []=((DataBufferInt)img.getRaster().getDataBuffer()).getData(); And here I is next problem: How can I change the value of each r,g,b and show that new image on my panel

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  • What could possibly be causing this NPE in onCreate?

    - by Adam Johns
    I am getting an NPE in onCreate of the following file (MySubActivity): public class MySubActivity extends MySuperActivity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); myTextView.setText(getResources().getString(R.string.myString)); } } MySuperActivity: public class MySuperActivity extends Activity { protected TextView myTextView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.my_layout); myTextView = (TextView)findViewById(R.id.myTextViewid); } } The strange thing is that I have never seen this crash while testing the app. The page works fine when I test it. However I got a crash report from Google notifying me of the crash. I cannot reproduce it, and I have no idea under what scenario this crash could happen. Seeing as how it works for me, the resource ids and string names etc. must be correct. The only thing that came across my mind was that maybe the user had their phone set to a different language, so it couldn't properly pull the resources. However, there are default resources for all of them, and I tested changing the language of my emulator and it didn't crash. Any ideas?

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  • How to setPage() a JEditorPane with a localfile which is outside of the .jar file?

    - by Jaguar
    My program has the following path in the .jar file src/test/Program.class and my program is as follow... Program.java package test; import java.io.File; import java.io.IOException; import javax.swing.JEditorPane; import javax.swing.JFrame; public class Program { JEditorPane editorPane; public Program() { File file = new File("temp.htm"); try { file.createNewFile(); editorPane = new JEditorPane(); editorPane.setPage(Program.class.getResource("temp.htm")); } catch (IOException e) { e.printStackTrace(); } } public JEditorPane getEditorPane(){ return editorPane; } public static void main(String[] args) { JFrame frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(400, 400); frame.setVisible(true); Program p = new Program(); frame.getContentPane().add(p.getEditorPane()); } } The problem is that I have compiled the program in a .jar file. The file.createNewFile(); creates the temp.htm file outside the .jar file So when editorPane.setPage(Program.class.getResource("temp.htm")); is called the file is not found as it searches for file inside the test package. How to setPage() the temp.htm file whiich is outside the .jar file but in the same folder as the .jar file? As the temp.htm is a localfile and I want a relative path instead of an absolute path. Thanks.

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  • Updating database row from model

    - by Jamie Dixon
    Hey everyone, I'm haing a few problems updating a row in my database using Linq2Sql. Inside of my model I have two methods for updating and saving from my controller, which in turn receives an updated model from my view. My model methods like like: public void Update(Activity activity) { _db.Activities.InsertOnSubmit(activity); } public void Save() { _db.SubmitChanges(); } and the code in my Controller likes like: [HttpPost] public ActionResult Edit(Activity activity) { if (ModelState.IsValid) { UpdateModel<Activity>(activity); _activitiesModel.Update(activity); _activitiesModel.Save(); } return View(activity); } The problem I'm having is that this code inserts a new entry into the database, even though the model item i'm inserting-on-submit contains a primary key field. I've also tried re-attaching the model object back to the data source but this throws an error because the item already exists. Any pointers in the right direction will be greatly appreciated. UPDATE: I'm using dependancy injection to instantiate my datacontext object as follows: IMyDataContext _db; public ActivitiesModel(IMyDataContext db) { _db = db; }

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  • Javascript Object Properties go to undefined after ajax request returns

    - by adasdas
    if you have an object and set a property for it, you can access that property in a function called on that object. but if you call a function and do an ajax request such that a different function is called from onreadystatechange, that secondary response function does not have access to the property. Thats a little confusing so see what I mean here. The property this.name is the one that changes. //from W3Schools website function getXHR(){if (window.XMLHttpRequest){return new XMLHttpRequest();}if (window.ActiveXObject){return new ActiveXObject("Microsoft.XMLHTTP");}return null;} function TestObject() { this.name = ""; //public var xhr = null; //private var response = function() //private { if(xhr.readyState > 3) { alert("B: my name is " + this.name); } } this.send = function() //public { alert("A: my name is " + this.name); if(xhr === null) { xhr = getXHR(); } var url = "http://google.com"; xhr.onreadystatechange = response; xhr.open("GET", url, true); xhr.send(null); } } var o = new TestObject(); o.name = "Ice Cube"; o.send(); Results are: A: my name is IceCube B: my name is undefined If response is public this happens as well. If xhr is public this also happens. Something occurs so that the response function called doesnt have access to the same parameters.

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  • Binding between Usercontrol with listbox and parent control (MVVM)

    - by walkor
    I have a UserControl which contains a listbox and few buttons. <UserControl x:Class="ItemControls.ListBoxControl" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"> <Grid> <ListBox:ExtendedListBox SelectionMode="Single" ItemsSource="{Binding LBItems}" Height="184"> <ListBox.ItemTemplate> <DataTemplate> <CheckBox Content="{Binding}"/> </DataTemplate> </ListBox.ItemTemplate> </ListBox> <Button Command="RemoveCommand"/> </Grid> </UserControl> And the code behind: public static readonly DependencyProperty RemoveCommandProperty = DependencyProperty.Register("RemoveCommand", typeof(ICommand), typeof(ListBoxControl), null); public ICommand RemoveCommand { get { return (ICommand)GetValue(RemoveCommandProperty); } set { SetValue(RemoveCommandProperty, value); } } public static readonly DependencyProperty LBItemsProperty = DependencyProperty.Register("LBItems", typeof(IEnumerable), typeof(ListBoxControl), null); public IEnumerable LBItems { get { return (IEnumerable)GetValue(LBItemsProperty); } set { SetValue(LBItemsProperty, value); } } I'm using this control in the view like this: <ItemControls:ListBoxControl Height="240" Width="350" LBItems="{Binding Items, Converter={StaticResource ItemsConverter}, Mode=TwoWay}" RemoveCommand="{Binding RemoveCommand}"/> The command works fine, though the listbox binding doesn't. My question is - WHY?

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  • Why does this code sample produce a memory leak?

    - by citronas
    In the university we were given the following code sample and we were being told, that there is a memory leak when running this code. The sample should demonstrate that this is a situation where the garbage collector can't work. As far as my object oriented programming goes, the only codeline able to create a memory leak would be items=Arrays.copyOf(items,2 * size+1); The documentation says, that the elements are copied. Does that mean the reference is copied (and therefore another entry on the heap is created) or the object itself is being copied? As far as I know, Object and therefore Object[] are implemented as a reference type. So assigning a new value to 'items' would allow the garbage collector to find that the old 'item' is no longer referenced and can therefore be collected. In my eyes, this the codesample does not produce a memory leak. Could somebody prove me wrong? =) import java.util.Arrays; public class Foo { private Object[] items; private int size=0; private static final int ISIZE=10; public Foo() { items= new Object[ISIZE]; } public void push(final Object o){ checkSize(); items[size++]=o; } public Object pop(){ if (size==0) throw new ///... return items[--size]; } private void checkSize(){ if (items.length==size){ items=Arrays.copyOf(items,2 * size+1); } } }

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  • Pythagoras tree with g2d

    - by owca
    I'm trying to build my first fractal (Pythagoras Tree): in Java using Graphics2D. Here's what I have now : import java.awt.*; import java.awt.geom.*; import javax.swing.*; import java.util.Scanner; public class Main { public static void main(String[] args) { int i=0; Scanner scanner = new Scanner(System.in); System.out.println("Give amount of steps: "); i = scanner.nextInt(); new Pitagoras(i); } } class Pitagoras extends JFrame { private int powt, counter; public Pitagoras(int i) { super("Pythagoras Tree."); setSize(1000, 1000); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); powt = i; } private void paintIt(Graphics2D g) { double p1=450, p2=800, size=200; for (int i = 0; i < powt; i++) { if (i == 0) { g.drawRect((int)p1, (int)p2, (int)size, (int)size); counter++; } else{ if( i%2 == 0){ //here I must draw two squares } else{ //here I must draw right triangle } } } } @Override public void paint(Graphics graph) { Graphics2D g = (Graphics2D)graph; paintIt(g); } So basically I set number of steps, and then draw first square (p1, p2 and size). Then if step is odd I need to build right triangle on the top of square. If step is even I need to build two squares on free sides of the triangle. What method should I choose now for drawing both triangle and squares ? I was thinking about drawing triangle with simple lines transforming them with AffineTransform but I'm not sure if it's doable and it doesn't solve drawing squares.

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  • Is there any point in using a volatile long?

    - by Adamski
    I occasionally use a volatile instance variable in cases where I have two threads reading from / writing to it and don't want the overhead (or potential deadlock risk) of taking out a lock; for example a timer thread periodically updating an int ID that is exposed as a getter on some class: public class MyClass { private volatile int id; public MyClass() { ScheduledExecutorService execService = Executors.newScheduledThreadPool(1); execService.scheduleAtFixedRate(new Runnable() { public void run() { ++id; } }, 0L, 30L, TimeUnit.SECONDS); } public int getId() { return id; } } My question: Given that the JLS only guarantees that 32-bit reads will be atomic is there any point in ever using a volatile long? (i.e. 64-bit). Caveat: Please do not reply saying that using volatile over synchronized is a case of pre-optimisation; I am well aware of how / when to use synchronized but there are cases where volatile is preferable. For example, when defining a Spring bean for use in a single-threaded application I tend to favour volatile instance variables, as there is no guarantee that the Spring context will initialise each bean's properties in the main thread.

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  • How to collect and inject all beans of a given type in Spring XML configuration

    - by GrzegorzOledzki
    One of the strongest accents of the Spring framework is the Dependency Injection concept. I understand one of the advices behind that is to separate general high-level mechanism from low-level details (as announced by Dependency Inversion Principle). Technically, that boils down to having a bean implementation to know as little as possible about a bean being injected as a dependency, e.g. public class PrintOutBean { private LogicBean logicBean; public void action() { System.out.println(logicBean.humanReadableDetails()); } //... } <bean class="PrintOutBean"> <property name="loginBean" ref="ShoppingCartBean"/> </bean> But what if I wanted to a have a high-level mechanism operating on multiple dependent beans? public class MenuManagementBean { private Collection<Option> options; public void printOut() { for (Option option:options) { // do something for option } //... } } I know one solution would be to use @Autowired annotation in the singleton bean, that is... @Autowired private Collection<Option> options; But doesn't it violate the separation principle? Why do I have to specify what dependents to take in the very same place I use them (i.e. MenuManagementBean class in my example)? Is there a way to inject collections of beans in the XML configuration like this (without any annotation in the MMB class)? <bean class="MenuManagementBean"> <property name="options"> <xxx:autowire by-type="MyOptionImpl"/> </property> </bean>

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  • .NET binary serialization conditionally without ISerializable

    - by SillyWhy
    I got 2 classes, for example: public class A { private B b; ... } public class B { ... } I need to serialize an object A using BinaryFormatter. When remoting it shall include the field b, but not when serialize to file. Here is what I added: [Serializable] public class A : MarshalByRefObject { private B b; [OnSerializing] private void OnSerializing(StreamingContext context) { if (context.State == StreamingContextStates.File) { this.b = null; } } ... } [Serializable] public class B : MarshalByRefObject { ... } I think this is a bad design because if another class C also contains B, in class C we must add the duplicate OnSerializing() logic as in A. Class B should decide what to do, not class A or C. I don't want to use ISerializable interface because there are too many variables in class B have to be added to SerializationInfo. I can create a SerializationSurrogate for class B, which perform nothing in GetObjectData() & SetObjectData(), then use it when serializing to file. However the same maintenance issue because whoever modify class B can't notice what going to happen during serialization & the existence of SerializationSurrogate. Is there a better alternative?

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  • Hibernate Search + Spring

    - by Zane
    I'm trying to integrate Hibernate Search with Spring, but I can't seem to index anything. I was able to get Hibernate Search to work without Spring, but I'm having a problem integrating it with Spring. Any help would be much appreciated. Below is my springmvc-servlet.xml: <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <property name="persistenceUnitName" value="enewsclipsPersistenceUnit" /> </bean> And here is my DAO class: @Repository public class SearchDaoImpl implements SearchDao { JpaTemplate jpaTemplate; @Autowired public SearchDaoImpl(EntityManagerFactory entityManagerFactory) { this.jpaTemplate = new JpaTemplate(entityManagerFactory); } @SuppressWarnings("unchecked") public void updateSearchIndex() { /* Implement the callback method */ jpaTemplate.execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { List<Article> articles = em.createQuery("select a from Article a").getResultList(); FullTextEntityManager ftEm = Search.getFullTextEntityManager(em); ftEm.getTransaction().begin(); for(Article article : articles) { System.out.println("Indexing Item " + article.getTitle()); ftEm.index(article); } ftEm.getTransaction().commit(); return null; } }); } } I think that it may have to do with the transactions but I'm not exactly sure. If you could just point me in the right direction, that would be helpful too! Thank you.

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  • How to rewrite data-driven test suites of JUnit 3 in Junit 4?

    - by rics
    I am using data-driven test suites running JUnit 3 based on Rainsberger's JUnit Recipes. The purpose of these tests is to check whether a certain function is properly implemented related to a set of input-output pairs. Here is the definition of the test suite: public static Test suite() throws Exception { TestSuite suite = new TestSuite(); Calendar calendar = GregorianCalendar.getInstance(); calendar.set(2009, 8, 05, 13, 23); // 2009. 09. 05. 13:23 java.sql.Date date = new java.sql.Date(calendar.getTime().getTime()); suite.addTest(new DateFormatTestToString(date, JtDateFormat.FormatType.YYYY_MON_DD, "2009-SEP-05")); suite.addTest(new DateFormatTestToString(date, JtDateFormat.FormatType.DD_MON_YYYY, "05/SEP/2009")); return suite; } and the definition of the testing class: public class DateFormatTestToString extends TestCase { private java.sql.Date date; private JtDateFormat.FormatType dateFormat; private String expectedStringFormat; public DateFormatTestToString(java.sql.Date date, JtDateFormat.FormatType dateFormat, String expectedStringFormat) { super("testGetString"); this.date = date; this.dateFormat = dateFormat; this.expectedStringFormat = expectedStringFormat; } public void testGetString() { String result = JtDateFormat.getString(date, dateFormat); assertTrue( expectedStringFormat.equalsIgnoreCase(result)); } } How is it possible to test several input-output parameters of a method using JUnit 4? This question and the answers explained to me the distinction between JUnit 3 and 4 in this regard. This question and the answers describe the way to create test suite for a set of class but not for a method with a set of different parameters.

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  • Get Object from memory using memory adresse

    - by Hamza Karmouda
    I want to know how to get an Object from memory, in my case a MediaRecorder. Here's my class: Mymic class: public class MyMic { MediaRecorder recorder2; File file; private Context c; public MyMic(Context context){ this.c=context; } private void stopRecord() throws IOException { recorder2.stop(); recorder2.reset(); recorder2.release(); } private void startRecord() { recorder2= new MediaRecorder(); recorder2.setAudioSource(MediaRecorder.AudioSource.MIC); recorder2.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); recorder2.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); recorder2.setOutputFile(file.getPath()); try { recorder2.prepare(); recorder2.start(); } catch (IllegalStateException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } my Receiver Class: public class MyReceiver extends BroadcastReceiver { private Context c; private MyMic myMic; @Override public void onReceive(Context context, Intent intent) { this.c=context; myMic = new MyMic(c); if(my condition = true){ myMic.startRecord(); }else myMic.stopRecord(); } } So when I'm calling startRecord() it create a new MediaRecorder but when i instantiate my class a second time i can't retrieve my Object. Can i retrieve my MediaRecorder with his addresse

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  • Is locking on the requested object a bad idea?

    - by Quick Joe Smith
    Most advice on thread safety involves some variation of the following pattern: public class Thing { private static readonly object padlock = new object(); private string stuff, andNonsense; public string Stuff { get { lock (Thing.padlock) { if (this.stuff == null) this.stuff = "Threadsafe!"; } return this.stuff; } } public string AndNonsense { get { lock (Thing.padlock) { if (this.andNonsense == null) this.andNonsense = "Also threadsafe!"; } return this.andNonsense; } } // Rest of class... } In cases where the get operations are expensive and unrelated, a single locking object is unsuitable because a call to Stuff would block all calls to AndNonsense, degrading performance. And rather than create a lock object for each call, wouldn't it be better to acquire the lock on the member itself (assuming it is not something that implements SyncRoot or somesuch for that purpose? For example: public string Stuff { get { lock (this.stuff) { // Pretend that this is a very expensive operation. if (this.stuff == null) this.stuff = "Still threadsafe and good?"; } return this.stuff; } } Strangely, I have never seen this approach recommended or warned against. Am I missing something obvious?

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  • uploading database file in assets not returning a record

    - by Alexander
    I have a problem with a database file not being read I have added the database file in assets called mydb but when i run my code it says its not being located. It is calling this toast Toast.makeText(this, "No contact found", Toast.LENGTH_LONG).show(); This is being called because no records are being returned. This is an example form Android Application Development book. public class DatabaseActivity extends Activity { /** Called when the activity is first created. */ TextView quest, response1, response2; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); TextView quest = (TextView) findViewById(R.id.quest); try { String destPath = "/data/data/" + getPackageName() + "/databases/MyDB"; File f = new File(destPath); if (!f.exists()) { CopyDB( getBaseContext().getAssets().open("mydb"), new FileOutputStream(destPath)); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } DBAdapter db = new DBAdapter(this); //---get a contact--- db.open(); Cursor c = db.getContact(2); if (c.moveToFirst()) DisplayContact(c); else Toast.makeText(this, "No contact found", Toast.LENGTH_LONG).show(); db.close(); } public void CopyDB(InputStream inputStream, OutputStream outputStream) throws IOException { //---copy 1K bytes at a time--- byte[] buffer = new byte[1024]; int length; while ((length = inputStream.read(buffer)) > 0) { outputStream.write(buffer, 0, length); } inputStream.close(); outputStream.close(); } public void DisplayContact(Cursor c) { quest.setText(String.valueOf(c.getString(1))); //quest.setText(String.valueOf("this is a text string")); } }

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  • How do I pass dependency to object with Castle Windsor and MS Test?

    - by Nick
    I am trying to use Castle Windsor with MS Test. The test class only seems to use the default constructor. How do I configure Castle to resolve the service in the constructor? Here is the Test Class' constructors: private readonly IWebBrowser _browser; public DepressionSummaryTests() { } public DepressionSummaryTests(IWebBrowser browser) { _browser = browser; } My component in the app config looks like so: <castle> <components> <component id="browser" service="ConversationSummary.IWebBrowser, ConversationSummary" type="ConversationSummary.Browser" /> </components> </castle> Here is my application container: public class ApplicationContainer : WindsorContainer { private static IWindsorContainer container; static ApplicationContainer() { container = new WindsorContainer(new XmlInterpreter(new ConfigResource("castle"))); } private static IWindsorContainer Container { get { return container; } } public static IWebBrowser Browser { get { return (IWebBrowser) Container.Resolve("browser"); } } } MS test requires the default constructor. What am I missing? Thanks!

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  • JPA returning null for deleted items from a set

    - by Jon
    This may be related to my question from a few days ago, but I'm not even sure how to explain this part. (It's an entirely different parent-child relationship.) In my interface, I have a set of attributes (Attribute) and valid values (ValidValue) for each one in a one-to-many relationship. In the Spring MVC frontend, I have a page for an administrator to edit these values. Once it's submitted, if any of these fields (as <input> tags) are blank, I remove the ValidValue object like so: Set<ValidValue> existingValues = new HashSet<ValidValue>(attribute.getValidValues()); Set<ValidValue> finalValues = new HashSet<ValidValue>(); for(ValidValue validValue : attribute.getValidValues()) { if(!validValue.getValue().isEmpty()) { finalValues.add(validValue); } } existingValues.removeAll(finalValues); for(ValidValue removedValue : existingValues) { getApplicationDataService().removeValidValue(removedValue); } attribute.setValidValues(finalValues); getApplicationDataService().modifyAttribute(attribute); The problem is that while the database is updated appropriately, the next time I query for the Attribute objects, they're returned with an extra entry in their ValidValue set -- a null, and thus, the next time I iterate through the values to display, it shows an extra blank value in the middle. I've confirmed that this happens at the point of a merge or find, at the point of "Execute query ReadObjectQuery(entity.Attribute). Here's the code I'm using to modify the database (in the ApplicationDataService): public void modifyAttribute(Attribute attribute) { getJpaTemplate().merge(attribute); } public void removeValidValue(ValidValue removedValue) { ValidValue merged = getJpaTemplate().merge(removedValue); getJpaTemplate().remove(merged); } Here are the relevant parts of the entity classes: Entity @Table(name = "attribute") public class Attribute { @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "attribute") private Set<ValidValue> validValues = new HashSet<ValidValue>(0); } @Entity @Table(name = "valid_value") public class ValidValue { @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "attr_id", nullable = false) private Attribute attribute; }

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  • Getting functions of inherited functions to be called

    - by wrongusername
    Let's say I have a base class Animal from which a class Cow inherits, and a Barn class containing an Animal vector, and let's say the Animal class has a virtual function scream(), which Cow overrides. With the following code: Animal.h #ifndef _ANIMAL_H #define _ANIMAL_H #include <iostream> using namespace std; class Animal { public: Animal() {}; virtual void scream() {cout << "aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh..." << endl;} }; #endif /* _ANIMAL_H */ Cow.h #ifndef _COW_H #define _COW_H #include "Animal.h" class Cow: public Animal { public: Cow() {} void scream() {cout << "MOOooooOOOOOOOO!!!" << endl;} }; #endif /* _COW_H */ Barn.h #ifndef _BARN_H #define _BARN_H #include "Animal.h" #include <vector> class Barn { std::vector<Animal> animals; public: Barn() {} void insertAnimal(Animal animal) {animals.push_back(animal);} void tortureAnimals() { for(int a = 0; a < animals.size(); a++) animals[a].scream(); } }; #endif /* _BARN_H */ and finally main.cpp #include <stdlib.h> #include "Barn.h" #include "Cow.h" #include "Chicken.h" /* * */ int main(int argc, char** argv) { Barn barn; barn.insertAnimal(Cow()); barn.tortureAnimals(); return (EXIT_SUCCESS); } I get this output: aaaAAAAAAAAAAGHHHHHHHHHH!!! ahhh... How should I code this to get MOOooooOOOOOOOO!!! (and whatever other classes inheriting Animal wants scream() to be) instead?

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  • Sending data back to Controller Spring-MVC

    - by Umesh Awasthi
    I am not sure if this is a complex problem but as a starting person this seems a bit complex to me. I have an object based on which i need to show some values on the UI and let user select some of them, i need to send data back to another controller when user click on the submit button.Here is the structure of my data object public class PrsData{ private Map<String, List<PrsCDData>> prsCDData; } public class PrsCDData{ private Map<String, Collection<ConfiguredDesignData>> configuredDesignData; } public ConfiguredDesignData{ // simple fields } I have set the object in model before showing the view like model.addAttribute("prsData", productData.getPrData()); In the form i have following settings <form:form method="post" commandName="prsData" action="${addProductToCartAction}" > <form:hidden path="prsCDData['${prsCDDataMap.key}'] [${status.index}].configuredDesignData['${configuredDesignDataMap.key}'] [${configuredDesignDataStatus.index}].code"/> <form:hidden path="prsCDData['${prsCDDataMap.key}'] [${status.index}].configuredDesignData['${configuredDesignDataMap.key}'] [${configuredDesignDataStatus.index}].description"/> </form:form> This is what i have at AddProductToCartController public String addToCart(@RequestParam("productCodePost") final String code, @ModelAttribute("prsData") final PrsData prsData, final Model model, @RequestParam(value = "qty", required = false, defaultValue = "1") final long qty) On submitting the form i am getting following exception org.springframework.beans.NullValueInNestedPathException: Invalid property 'prsCDData[Forced][0]' of bean class [com.product.data.PrsData]: Cannot access indexed value of property referenced in indexed property path 'prsCDData[Forced][0]': returned null It seems like its trying to access the values on this controller while i am trying to send value to that controller and trying to create same object with selected values Can any one tell me where i am doing wrong and what i need to take care of

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  • Inheritence and usage of dynamic_cast

    - by Mewzer
    Hello, Suppose I have 3 classes as follows (as this is an example, it will not compile!): class Base { public: Base(){} virtual ~Base(){} virtual void DoSomething() = 0; virtual void DoSomethingElse() = 0; }; class Derived1 { public: Derived1(){} virtual ~Derived1(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD1DoSomething{ ... } }; class Derived2 { public: Derived2(){} virtual ~Derived2(){} virtual void DoSomething(){ ... } virtual void DoSomethingElse(){ ... } virtual void SpecialD2DoSomething{ ... } }; I want to create an instance of Derived1 or Derived2 depending on some setting that is not available until run-time. As I cannot determine the derived type until run-time, then do you think the following is bad practice?... class X { public: .... void GetConfigurationValue() { .... // Get configuration setting, I need a "Derived1" b = new Derived1(); // Now I want to call the special DoSomething for Derived1 (dynamic_cast<Derived1*>(b))->SpecialD1DoSomething(); } private: Base* b; }; I have generally read that usage of dynamic_cast is bad, but as I said, I don't know which type to create until run-time. Please help!

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  • Working with PHP and MySQL - need a good and secure design with OO design

    - by Andrew
    I am new to PHP- first time developer. I am working on my web application and it is nearly done; nevertheless, most of my sql was done directly via code using direct mysql requests. This is the way I approached it: In classes_db.php I declared the db settings and created methods that I use to open and close DB connections. I declare those objects on my regular pages: class classes_db { public $dbserver = 'server; public $dbusername = 'user'; public $dbpassword = 'pass'; public $dbname = 'db'; function openDb() { $dbhandle = mysql_connect($this->dbserver, $this->dbusername, $this->dbpassword); if (!$dbhandle) { die('Could not connect: ' . mysql_error()); } $selected = mysql_select_db($this->dbname, $dbhandle) or die("Could not select the database"); return $dbhandle; } function closeDb($con) { mysql_close($con); } } On my regular page, I do this: <?php require 'classes_db.php'; session_start(); //create instance of the DB class $db = new classes_db(); //get dbhandle $dbhandle = $db->openDb(); //process query $result = mysql_query("update user set username = '" . $usernameFromForm . "' where iduser= " . $_SESSION['user']->iduser); //close the connection if (isset($dbhandle)) { $db->closeDb($dbhandle); } ?> My questions is: how to do it right and make it OO and secure? I know that I need incorporate prepared queries- how to do it the best way? Please provide some code

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