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  • Designing a class in such a way that it doesn't become a "God object"

    - by devoured elysium
    I'm designing an application that will allow me to draw some functions on a graphic. Each function will be drawn from a set of points that I will pass to this graphic class. There are different kinds of points, all inheriting from a MyPoint class. For some kind of points it will be just printing them on the screen as they are, others can be ignored, others added, so there is some kind of logic associated to them that can get complex. How to actually draw the graphic is not the main issue here. What bothers me is how to make the code logic such that this GraphicMaker class doesn't become the so called God-Object. It would be easy to make something like this: class GraphicMaker { ArrayList<Point> points = new ArrayList<Point>(); public void AddPoint(Point point) { points.add(point); } public void DoDrawing() { foreach (Point point in points) { if (point is PointA) { //some logic here else if (point is PointXYZ) { //...etc } } } } How would you do something like this? I have a feeling the correct way would be to put the drawing logic on each Point object (so each child class from Point would know how to draw itself) but two problems arise: There will be kinds of points that need to know all the other points that exist in the GraphicObject class to know how to draw themselves. I can make a lot of the methods/properties from the Graphic class public, so that all the points have a reference to the Graphic class and can make all their logic as they want, but isn't that a big price to pay for not wanting to have a God class?

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  • Clicking on MenuItem without clicking on the text

    - by pringlesinn
    I've got a Menu, and I want to click on the menu, but not on the text if you guys know what i mean. The MenuItem has a border, or something like this, but when I click on it it won't redirect to the page I want unless I click on text. Is it possible to click on the whole "Button" and redirect or do what is need to do? My menu is like this: <rich:dropDownMenu showDelay="250" hideDelay="0" submitMode="none"> <f:facet name="label">Tools</f:facet> <rich:menuItem> <s:link view="/pages/tools/ppaParameters/PpaParametersEdit.xhtml" value="Parameters" id="PpaParametersId" includePageParams="false" propagation="none"/> </rich:menuItem> <rich:menuGroup value="Security"> <rich:menuItem> <s:link view="/pages/tools/security/ppaModule/PpaModuleEdit.xhtml" value="Module" id="PpaModuleId" includePageParams="false" propagation="none" /> </rich:menuItem> </rich:menuGroup> </rich:dropDownMenu> There's an example. I need to click on text to make it work out.

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  • Inheritance or identifier

    - by Lina
    Hi! Does anyone here have opinions about when to user inheritance and when to use an identifier instead? Inheritance example: class Animal { public int Name { get; set; } } class Dog : Animal {} class Cat : Animal {} Identifier example: class Animal { public int Name { get; set; } public AnimalType { get; set; } } In what situations should i prefer which solution and what are the pros and cons for them? /Lina

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  • Hibernate: Querying objects by attributes of inherited classes

    - by MichaelD
    Hi all, I ran into a problem with Hibernate concerning queries on classes which use inheritance. Basically I've the following class hierarchy: @Entity @Table( name = "recording" ) class Recording { ClassA attributeSet; ... } @Entity @Inheritance( strategy = InheritanceType.JOINED ) @Table( name = "classA" ) public class ClassA { String Id; ... } @Entity @Table( name = "ClassB1" ) @PrimaryKeyJoinColumn( name = "Id" ) public class ClassB1 extends ClassA { private Double P1300; private Double P2000; } @Entity @Table( name = "ClassB2" ) @PrimaryKeyJoinColumn( name = "Id" ) public class ClassB2 extends ClassA { private Double P1300; private Double P3000; } The hierarchy is already given like this and I cannot change it easily. As you can see ClassB1 and ClassB2 inherit from ClassA. Both classes contain a set of attributes which sometimes even have the same names (but I can't move them to ClassA since there are possible more sub-classes which do not use them). The Recording class references one instance of one of this classes. Now my question: What I want to do is selecting all Recording objects in my database which refer to an instance of either ClassB1 or ClassB2 with e.g. the field P1300 == 15.5 (so this could be ClassB1 or ClassB2 instances since the P1300 attribute is declared in both classes). What I tried is something like this: Criteria criteria = session.createCriteria(Recording.class); criteria.add( Restrictions.eq( "attributeSet.P1300", new Double(15.5) ) ); criteria.list(); But since P1300 is not an attribute of ClassA hibernate throws an exception telling me: could not resolve property: P1300 of: ClassA How can I tell hibernate that it should search in all subclasses to find the attribute I want to filter? Thanks MichaelD

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  • Is it bad to have multiple return statements?

    - by scot
    Hi, I have a code somethg like below: int method(string a ,int b , int c){ if(cond1) return -1; if(cond2 || cond3) return 3; if(cond1 && cond2) return 0; else return -999; } Does it perform badly when compared to having multiple if else and have single return?

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  • hibernate for dynamic table creation

    - by user369316
    i AM A HIBERNATE BEGINNER ,Since i need to create dynamic tables with dynamic fields in them i chose to use hibernate . As far as my understanding , creating tables requires a class with the fields defined in the class . How do i generate the classes dynamically based on the table with the required fields ?

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  • Need to map classes to different databases at runtime in Hibernate

    - by serg555
    I have MainDB database and unknown number (at compile time) of UserDB_1, ..., UserDB_N databases. MainDB contains names of those UserDB databases in some table (new UserDB can be created at runtime). All UserDB have exactly the same table names and fields. How to handle such situation in Hibernate? (database structure cannot be changed). Currently I am planning to create generic User classes not mapped to anything and just use native SQL for all queries: session.createSQLQuery("select * from " + db + ".user where id=1") .setResultTransformer(Transformers.aliasToBean(User.class)); Is there anything better I can do? Ideally I would want to have mappings for UserDB tables and relations and use HQL on required database.

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  • Remove stateful EJB bean in client

    - by palto
    I'm currently learning EJB and as I understand when client gets a stateful session bean the server keeps it in memory(or passivates it) until the client removes the bean. Pretty simple, except nowhere I have seen any examples of how the client can actually remove the bean. How do you do that other than shutting down your client application? Or do I just have to implement a reset method in all my stateful beans if I want to start over?

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  • JToolbar is hidden by JMenu

    - by pierre
    I'm using Netbeans to add a JToolbar to my window which also has a JMenuBar. Here is the design-time look: .. but during run-time I get this: With the toolbar seemingly partially hidden under the menu names. This is on the Mac, btw. Is there something stupid I've forgotten to do or some layout trick I should be using? EDIT: I'll add that the area below the toolbar is a SplitContainer.

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  • Counting down to zero in contrast to counting up to length - 1

    - by Helper Method
    Is it recommended to count in small loops (where possible) down from length - 1 to zero instead of counting up to length - 1? 1.) Counting down for (int i = a.length - 1; i >= 0; i--) { if (a[i] == key) return i; } 2.) Counting up for (int i = 0; i < a.length; i++) { if (a[i] == key) return i; } The first one is slightly faster that the second one (because comparing to zero is faster) but is a little more error-prone in my opinion. Besides, the first one could maybe not be optimized by future improvements of the JVM. Any ideas on that?

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  • How to display the properties of the current selected component in a JPanel using the Netbeans Platf

    - by Burmudar
    I am currently building a small visual designer using the Netbeans Platform. All my components that can be placed on the JPanel show correctly in the Palette Window. What I am struggling to do at the moment, is to let the property window show the properties of the component that was either just dragged and dropped or showing the currently selected component in the JPanel in the Properties window. Any help would be greatly appreciated.

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  • Children in Enumeration

    - by marionmaiden
    Hello I have a enumeration for elements in a JTree When I find some specific element in this JTree, I want to check it's children. Do the method children() in a Enumeration check it's grandcildren too? For example, let's supose this JTree, considering the identation as new levels of the tree: Fruits apple grape orange peach pineapple strawberry banana If I get the children of grape, will I have just orange and peach or will I get peach children (pineaple) too?

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  • JTree keep expanding problem

    - by newbie123
    I want to keep my jTree file expanded. I using below code to expand the jTree : public void expandAll(JTree tree) { int row = 0; while (row < tree.getRowCount()) { tree.expandRow(row); row++; } } It works, but when I add in new file or delete file the jtree collapse back. How can keep the jTree expanded?

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  • How to move point on arc?

    - by bbZ
    I am writing an app that is simulating RobotArm movement. What I want to achieve, and where I have couple of problems is moving a Point on arc (180degree) that is arm range of movement. I am moving an arm by grabbing with mouse end of arm (Elbow, the Point I was talking about), robot can have multiple arms with diffrent arm lenghts. If u can help me with this part, I'd be grateful. This is what I have so far, drawing function: public void draw(Graphics graph) { Graphics2D g2d = (Graphics2D) graph.create(); graph.setColor(color); graph.fillOval(location.x - 4, location.y - 4, point.width, point.height); //Draws elbow if (parentLocation != null) { graph.setColor(Color.black); graph.drawLine(location.x, location.y, parentLocation.x, parentLocation.y); //Connects to parent if (arc == null) { angle = new Double(90 - getAngle(parentInitLocation)); arc = new Arc2D.Double(parentLocation.x - (parentDistance * 2 / 2), parentLocation.y - (parentDistance * 2 / 2), parentDistance * 2, parentDistance * 2, 90 - getAngle(parentInitLocation), 180, Arc2D.OPEN); //Draws an arc if not drawed yet. } else if (angle != null) //if parent is moved, angle is moved also { arc = new Arc2D.Double(parentLocation.x - (parentDistance * 2 / 2), parentLocation.y - (parentDistance * 2 / 2), parentDistance * 2, parentDistance * 2, angle, 180, Arc2D.OPEN); } g2d.draw(arc); } if (spacePanel.getElbows().size() > level + 1) {//updates all childElbows position updateChild(graph); } } I just do not know how to prevent moving Point moving outside of arc line. It can not be inside or outside arc, just on it. Here I wanted to put a screenshot, sadly I don't have enough rep. Am I allowed to put link to this? Maybe you got other ways how to achieve this kind of thing. Here is the image: Red circle is actual state, and green one is what I want to do. EDIT2: As requested, repo link: https://github.com/dspoko/RobotArm

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  • Getting a variable out of a Public Void (Android)

    - by James Rattray
    I have this code: hubSpinner.setOnItemSelectedListener(new OnItemSelectedListener() { public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) { final MediaPlayer mp2 = MediaPlayer.create(Textbox.this, R.raw.hero); mp2.start(); } public void onNothingSelected(AdapterView<?> parentView) { } }); (The code basically runs when a new item is selected of a spinner and then plays a song, -which later will be a variable based on what was picked, but i'm fine as it is for now) Problem: And I want to be able to use 'mp2' out of this public void, (I want a button which pauses it) How can I do this? Please explain/show... Thanks alot James

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  • JBoss RMI Transaction

    - by EasyName
    Hi, How can i can achieve remote transaction while using Remote EJB (over RMI/IIOP or RMI/JRMP). Is that JBoss 4.0 support this kind of transaction or should i use jotm or atomikos? Thanks in advance

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  • Use continue or Checked Exceptions when checking and processing objects

    - by Johan Pelgrim
    I'm processing, let's say a list of "Document" objects. Before I record the processing of the document successful I first want to check a couple of things. Let's say, the file referring to the document should be present and something in the document should be present. Just two simple checks for the example but think about 8 more checks before I have successfully processed my document. What would have your preference? for (Document document : List<Document> documents) { if (!fileIsPresent(document)) { doSomethingWithThisResult("File is not present"); continue; } if (!isSomethingInTheDocumentPresent(document)) { doSomethingWithThisResult("Something is not in the document"); continue; } doSomethingWithTheSucces(); } Or for (Document document : List<Document> documents) { try { fileIsPresent(document); isSomethingInTheDocumentPresent(document); doSomethingWithTheSucces(); } catch (ProcessingException e) { doSomethingWithTheExceptionalCase(e.getMessage()); } } public boolean fileIsPresent(Document document) throws ProcessingException { ... throw new ProcessingException("File is not present"); } public boolean isSomethingInTheDocumentPresent(Document document) throws ProcessingException { ... throw new ProcessingException("Something is not in the document"); } What is more readable. What is best? Is there even a better approach of doing this (maybe using a design pattern of some sort)? As far as readability goes my preference currently is the Exception variant... What is yours?

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  • Panel is not displaying in JFrame

    - by mallikarjun
    I created a chat panel and added to Jframe but the panel is not displaying. But my sop in the chat panel are displaying in the console. Any one please let me know what could be the problem My Frame public class MyFrame extends JFrame { MyPanel chatClient; String input; public MyFrame() { input = (String)JOptionPane.showInputDialog(null, "Name:", "Connect to chat server", JOptionPane.QUESTION_MESSAGE, null,null, "Test"); input=input.trim(); chatClient = new MyPanel("localhost",input); setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); add(chatClient); } public static void main(String...args){ new MyFrame(); } } MyPanel: public class MyPanel extends JPanel{ ChatClient chatClient; public MyPanel(String host, String uid) { chatClient= new ChatClient(host,uid); add(chatClient.getChatPanel()); this.setVisible(true); } } chat panel: public class ChatClient { Client client; String name; ChatPanel chatPanel; String hostid; public ChatClient(String host,String uid){ client = new Client(); client.start(); System.out.println("in constructor"); Network.register(client); client.addListener(new Listener(){ public void connected(Connection connection){ System.out.println("in client connected method"); Network.RegisterName registerName = new Network.RegisterName(); registerName.name=name; client.sendTCP(registerName); } public void received(Connection connection,Object object){ System.out.println("in client received method"); if (object instanceof Network.UpdateNames) { Network.UpdateNames updateNames = (Network.UpdateNames)object; //chatFrame.setNames(updateNames.names); System.out.println("got it message"); return; } if (object instanceof Network.ChatMessage) { Network.ChatMessage chatMessage = (Network.ChatMessage)object; //chatFrame.addMessage(chatMessage.text); System.out.println("send it message"); return; } } }); // end of listner name=uid.trim(); hostid=host.trim(); chatPanel = new ChatPanel(hostid,name); chatPanel.setSendListener(new Runnable(){ public void run(){ Network.ChatMessage chatMessage = new Network.ChatMessage(); chatMessage.chatMessage=chatPanel.getSendText(); client.sendTCP(chatMessage); } }); new Thread("connect"){ public void run(){ try{ client.connect(5000, hostid,Network.port); }catch(IOException e){ e.printStackTrace(); } } }.start(); }//end of constructor static public class ChatPanel extends JPanel{ CardLayout cardLayout; JList messageList,nameList; JTextField sendText; JButton sendButton; JPanel topPanel,bottomPanel,panel; public ChatPanel(String host,String user){ setSize(600, 200); this.setVisible(true); System.out.println("Chat panel "+host+"user: "+user); { panel = new JPanel(new BorderLayout()); { topPanel = new JPanel(new GridLayout(1,2)); panel.add(topPanel); { topPanel.add(new JScrollPane(messageList=new JList())); messageList.setModel(new DefaultListModel()); } { topPanel.add(new JScrollPane(nameList=new JList())); nameList.setModel(new DefaultListModel()); } DefaultListSelectionModel disableSelections = new DefaultListSelectionModel() { public void setSelectionInterval (int index0, int index1) { } }; messageList.setSelectionModel(disableSelections); nameList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); } { bottomPanel = new JPanel(new GridBagLayout()); panel.add(bottomPanel,BorderLayout.SOUTH); bottomPanel.add(sendText=new JTextField(),new GridBagConstraints(0,0,1,1,1,0,GridBagConstraints.CENTER,GridBagConstraints.BOTH,new Insets(0,0,0,0),0,0)); bottomPanel.add(sendButton=new JButton(),new GridBagConstraints(1,0,1,1,0,0,GridBagConstraints.CENTER,0,new Insets(0,0,0,0),0,0)); } } sendText.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e){ sendButton.doClick(); } }); } public void setSendListener (final Runnable listener) { sendButton.addActionListener(new ActionListener() { public void actionPerformed (ActionEvent evt) { if (getSendText().length() == 0) return; listener.run(); sendText.setText(""); sendText.requestFocus(); } }); } public String getSendText () { return sendText.getText().trim(); } public void setNames (final String[] names) { EventQueue.invokeLater(new Runnable(){ public void run(){ DefaultListModel model = (DefaultListModel)nameList.getModel(); model.removeAllElements(); for(String name:names) model.addElement(name); } }); } public void addMessage (final String message) { EventQueue.invokeLater(new Runnable() { public void run () { DefaultListModel model = (DefaultListModel)messageList.getModel(); model.addElement(message); messageList.ensureIndexIsVisible(model.size() - 1); } }); } } public JPanel getChatPanel(){ return chatPanel; } }

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  • Trouble adding Image to a JPanel

    - by user1276078
    I'm making a video game, and I need to add an image to a JPanel and then add that JPanel to a JFrame. All of the tutorials I've seen say to add it to a JLabel, but the image needs to be able to move around. Unless you can move a JLabel around, I can't do that. How would I be able to add an Image directly to a JPanel. This is what I have so far, but it is just like it was on a JApplet class Penguin extends JPanel { public Image image; public void paintComponent( Graphics g ) { image = getImage( getDocumentBase(), "Penguins.jpg" ); g.drawImage( image, 0, 0, this ); } }

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  • KeyStore, HttpClient, and HTTPS: Can someone explain this code to me?

    - by stormin986
    I'm trying to understand what's going on in this code. KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType()); FileInputStream instream = new FileInputStream(new File("my.keystore")); try { trustStore.load(instream, "nopassword".toCharArray()); } finally { instream.close(); } SSLSocketFactory socketFactory = new SSLSocketFactory(trustStore); Scheme sch = new Scheme("https", socketFactory, 443); httpclient.getConnectionManager().getSchemeRegistry().register(sch); My Questions: trustStore.load(instream, "nopassword".toCharArray()); is doing what exactly? From reading the documentation load() will load KeyStore data from an input stream (which is just an empty file we just created), using some arbitrary "nopassword". Why not just load it with null as the InputStream parameter and an empty string as the password field? And then what is happening when this empty KeyStore is being passed to the SSLSocketFactory constructor? What's the result of such an operation? Or -- is this simply an example where in a real application you would have to actually put a reference to an existing keystore file / password?

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  • Best way to implement refusing a value change by the user in Swing?

    - by Michael Borgwardt
    I have a JCheckBox that should not be checked by the user when a certain other field is empty. So now I want to have an error popup and then reset the checkbox (I've considered disabling the checkbox, but the connection to the other field is non-obvious, and a tooltip text IMO not visible enough). What's the correct way to do that in Swing? Through a PropertyVetoException? Where do I throw it and where do I catch it? My first (probably ugly) idea would be to add a ChangeListener that itself shows the popup and resets the value.

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