Search Results

Search found 40870 results on 1635 pages for 'database design'.

Page 123/1635 | < Previous Page | 119 120 121 122 123 124 125 126 127 128 129 130  | Next Page >

  • Jdbc - Connect remote Mysql Database error

    - by Guilherme Ruiz
    I'm using JDBC to connect my program to a MySQL database. I already put the port number and yes, my database have permission to access. When i use localhost work perfectly, but when i try connect to a remote MySQL database, show this error on console. java.lang.ExceptionInInitializerError Caused by: java.lang.NumberFormatException: null at java.lang.Integer.parseInt(Integer.java:454) at java.lang.Integer.parseInt(Integer.java:527) at serial.BDArduino.<clinit>(BDArduino.java:25) Exception in thread "main" Java Result: 1 CONSTRUÍDO COM SUCESSO (tempo total: 1 segundo) Thank you in Advance ! MAIN CODE /* * To change this template, choose Tools | Templates * and open the template in the editor. */ package serial; import gnu.io.CommPort; import gnu.io.CommPortIdentifier; import gnu.io.SerialPort; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.swing.JFrame; import javax.swing.JOptionPane; /** * * @author Ruiz */ public class BDArduino extends JFrame { static boolean connected = false; static int aux_sql8 = Integer.parseInt(Sql.getDBinfo("SELECT * FROM arduinoData WHERE id=1", "pin8")); static int aux_sql2 = Integer.parseInt(Sql.getDBinfo("SELECT * FROM arduinoData WHERE id=1", "pin2")); CommPort commPort = null; SerialPort serialPort = null; InputStream inputStream = null; static OutputStream outputStream = null; String comPortNum = "COM10"; int baudRate = 9600; int[] intArray = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}; /** * Creates new form ArduinoTest */ public BDArduino() { //super("Arduino Test App"); initComponents(); } class Escrita extends Thread { private int i; public void run() { while (true) { System.out.println("Número :" + i++); } } } //public void actionPerformed(ActionEvent e) { // String arg = e.getActionCommand(); public static void writeData(int a) throws IOException { outputStream.write(a); } public void action(String arg) { System.out.println(arg); Object[] msg = {"Baud Rate: ", "9600", "COM Port #: ", "COM10"}; if (arg == "connect") { if (connected == false) { new BDArduino.ConnectionMaker().start(); } else { closeConnection(); } } if (arg == "disconnect") { serialPort.close(); closeConnection(); } if (arg == "p2") { System.out.print("Pin #2\n"); try { outputStream.write(intArray[0]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p3") { System.out.print("Pin #3\n"); try { outputStream.write(intArray[1]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p4") { System.out.print("Pin #4\n"); try { outputStream.write(intArray[2]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p5") { System.out.print("Pin #5\n"); try { outputStream.write(intArray[3]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p6") { System.out.print("Pin #6\n"); try { outputStream.write(intArray[4]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p7") { System.out.print("Pin #7\n"); try { outputStream.write(intArray[5]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p8") { System.out.print("Pin #8\n"); try { outputStream.write(intArray[6]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p9") { System.out.print("Pin #9\n"); try { outputStream.write(intArray[7]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p10") { System.out.print("Pin #10\n"); try { outputStream.write(intArray[8]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p11") { System.out.print("Pin #11\n"); try { outputStream.write(intArray[9]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p12") { System.out.print("Pin #12\n"); try { outputStream.write(intArray[10]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } if (arg == "p13") { System.out.print("Pin #12\n"); try { outputStream.write(intArray[11]); }//end try catch (IOException e12) { e12.printStackTrace(); System.exit(-1); }//end catch } } //******************************************************* //Arduino Connection *************************************** //****************************************************** void closeConnection() { try { outputStream.close(); } catch (Exception ex) { ex.printStackTrace(); String cantCloseConnectionMessage = "Can't Close Connection!"; JOptionPane.showMessageDialog(null, cantCloseConnectionMessage, "ERROR", JOptionPane.ERROR_MESSAGE); } connected = false; System.out.print("\nDesconectado\n"); String disconnectedConnectionMessage = "Desconectado!"; JOptionPane.showMessageDialog(null, disconnectedConnectionMessage, "Desconectado", JOptionPane.INFORMATION_MESSAGE); }//end closeConnection() void connect() throws Exception { String portName = comPortNum; CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier(portName); if (portIdentifier.isCurrentlyOwned()) { System.out.println("Error: Port is currently in use"); String portInUseConnectionMessage = "Port is currently in use!\nTry Again Later..."; JOptionPane.showMessageDialog(null, portInUseConnectionMessage, "ERROR", JOptionPane.ERROR_MESSAGE); } else { commPort = portIdentifier.open(this.getClass().getName(), 2000); if (commPort instanceof SerialPort) { serialPort = (SerialPort) commPort; serialPort.setSerialPortParams(baudRate, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE); outputStream = serialPort.getOutputStream(); } else { System.out.println("Error: Only serial ports are handled "); String onlySerialConnectionMessage = "Serial Ports ONLY!"; JOptionPane.showMessageDialog(null, onlySerialConnectionMessage, "ERROR", JOptionPane.ERROR_MESSAGE); } }//end else //wait some time try { Thread.sleep(300); } catch (InterruptedException ie) { } }//end connect //******************************************************* //*innerclasses****************************************** //******************************************************* public class ConnectionMaker extends Thread { public void run() { //try to make a connection try { connect(); } catch (Exception ex) { ex.printStackTrace(); System.out.print("ERROR: Cannot connect!"); String cantConnectConnectionMessage = "Cannot Connect!\nCheck the connection settings\nand/or your configuration\nand try again!"; JOptionPane.showMessageDialog(null, cantConnectConnectionMessage, "ERROR", JOptionPane.ERROR_MESSAGE); } //show status serialPort.notifyOnDataAvailable(true); connected = true; //send ack System.out.print("\nConnected\n"); String connectedConnectionMessage = "Conectado!"; JOptionPane.showMessageDialog(null, connectedConnectionMessage, "Conectado", JOptionPane.INFORMATION_MESSAGE); }//end run }//end ConnectionMaker /** * This method is called from within the constructor to initialize the form. * WARNING: Do NOT modify this code. The content of this method is always * regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // <editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() { btnp2 = new javax.swing.JButton(); btncon = new javax.swing.JButton(); btndesc = new javax.swing.JButton(); btnp3 = new javax.swing.JButton(); btnp4 = new javax.swing.JButton(); btnp5 = new javax.swing.JButton(); btnp9 = new javax.swing.JButton(); btnp6 = new javax.swing.JButton(); btnp7 = new javax.swing.JButton(); btnp8 = new javax.swing.JButton(); btn13 = new javax.swing.JButton(); btnp10 = new javax.swing.JButton(); btnp11 = new javax.swing.JButton(); btnp12 = new javax.swing.JButton(); setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); btnp2.setText("2"); btnp2.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp2MouseClicked(evt); } }); btncon.setText("Conectar"); btncon.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnconMouseClicked(evt); } }); btndesc.setText("Desconectar"); btndesc.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btndescMouseClicked(evt); } }); btnp3.setText("3"); btnp3.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp3MouseClicked(evt); } }); btnp4.setText("4"); btnp4.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp4MouseClicked(evt); } }); btnp5.setText("5"); btnp5.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp5MouseClicked(evt); } }); btnp9.setText("9"); btnp9.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp9MouseClicked(evt); } }); btnp6.setText("6"); btnp6.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp6MouseClicked(evt); } }); btnp7.setText("7"); btnp7.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp7MouseClicked(evt); } }); btnp8.setText("8"); btnp8.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp8MouseClicked(evt); } }); btn13.setText("13"); btn13.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btn13MouseClicked(evt); } }); btnp10.setText("10"); btnp10.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp10MouseClicked(evt); } }); btnp11.setText("11"); btnp11.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp11MouseClicked(evt); } }); btnp12.setText("12"); btnp12.addMouseListener(new java.awt.event.MouseAdapter() { public void mouseClicked(java.awt.event.MouseEvent evt) { btnp12MouseClicked(evt); } }); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addGap(20, 20, 20) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) .addGroup(layout.createSequentialGroup() .addComponent(btncon) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) .addComponent(btndesc)) .addGroup(layout.createSequentialGroup() .addComponent(btnp6, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp7, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp8, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp9, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGroup(layout.createSequentialGroup() .addComponent(btnp10, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp11, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp12, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btn13, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGroup(layout.createSequentialGroup() .addComponent(btnp2, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp3, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp4, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(btnp5, javax.swing.GroupLayout.PREFERRED_SIZE, 50, javax.swing.GroupLayout.PREFERRED_SIZE))) .addContainerGap(20, Short.MAX_VALUE)) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(layout.createSequentialGroup() .addContainerGap() .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE) .addComponent(btncon) .addComponent(btndesc)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 20, Short.MAX_VALUE) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(btnp2) .addComponent(btnp3) .addComponent(btnp4) .addComponent(btnp5)) .addGap(18, 18, 18) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(btnp6) .addComponent(btnp7) .addComponent(btnp8) .addComponent(btnp9)) .addGap(18, 18, 18) .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(btnp10) .addComponent(btnp11) .addComponent(btnp12) .addComponent(btn13)) .addGap(22, 22, 22)) ); pack(); }// </editor-fold> private void btnp2MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p2"); } private void btnconMouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("connect"); } private void btndescMouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("disconnect"); } private void btnp3MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p3"); } private void btnp4MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p4"); } private void btnp5MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here action("p5"); } private void btnp9MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p9"); } private void btnp6MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p6"); } private void btnp7MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p7"); } private void btnp8MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p8"); } private void btn13MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p13"); } private void btnp10MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p10"); } private void btnp11MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p11"); } private void btnp12MouseClicked(java.awt.event.MouseEvent evt) { // TODO add your handling code here: action("p12"); } /** * @param args the command line arguments */ public static void main(String args[]) throws IOException { /* Set the Nimbus look and feel */ //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) "> /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel. * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html */ try { for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) { if ("Nimbus".equals(info.getName())) { javax.swing.UIManager.setLookAndFeel(info.getClassName()); break; } } } catch (Exception e) { } //</editor-fold> /* Create and display the form */ java.awt.EventQueue.invokeLater(new Runnable() { public void run() { new BDArduino().setVisible(true); } }); //} while (true) { // int sql8 = Integer.parseInt(Sql.getDBinfo("SELECT * FROM arduinoData WHERE id=1", "pin8")); if (connected == true && sql8 != aux_sql8) { aux_sql8 = sql8; if(sql8 == 1){ writeData(2); }else{ writeData(3); } } int sql2 = Integer.parseInt(Sql.getDBinfo("SELECT * FROM arduinoData WHERE id=1", "pin2")); if (connected == true && sql2 != aux_sql2) { aux_sql2 = sql2; if(sql2 == 1){ writeData(4); }else{ writeData(5); } } try { Thread.sleep(500); } catch (InterruptedException e) { e.printStackTrace(); } } } // Variables declaration - do not modify private javax.swing.JButton btn13; private javax.swing.JButton btncon; private javax.swing.JButton btndesc; private javax.swing.JButton btnp10; private javax.swing.JButton btnp11; private javax.swing.JButton btnp12; private javax.swing.JButton btnp2; private javax.swing.JButton btnp3; private javax.swing.JButton btnp4; private javax.swing.JButton btnp5; private javax.swing.JButton btnp6; private javax.swing.JButton btnp7; private javax.swing.JButton btnp8; private javax.swing.JButton btnp9; // End of variables declaration }

    Read the article

  • Which of these methods provides for the fastest page loading?

    - by chromedude
    I am building a database in MySQL that will be accessed by PHP scripts. I have a table that is the activity stream. This includes everything that goes on on the website (following of many different things, liking, upvoting etc.). From this activity stream I am going to run an algorithm for each user depending on their activity and display relevant activity. Should I create another table that stores the activity for each user once the algorithm has been run on the activity or should I run the algorithm on the activity table every time the user accesses the site? UPDATE:(this is what is above except rephrased hopefully in an easier to understand way) I have a database table called activity. This table creates a new row every time an action is performed by a user on the website. Every time a user logs in I am going to run an algorithm on the new rows (since the users last login) in the table (activity) that apply to them. For example if the user is following a user who upvoted a post in the activity stream that post will be displayed when the user logs in. I want the ability for the user to be able to access previous content applying to them. Would it be easiest to create another table that saved the rows that have already been run over with the algorithm except attached to individual users names? (a row can apply to multiple different users)

    Read the article

  • Biztalk suspended messages in database

    - by WtFudgE
    Hi, I was wondering if some1 knows where I can see the data of a suspended message in the biztalk database. I need this because about 900 messages have been suspended because of a validation and I need to edit all of them, resuming isn't possible. I know that info of suspended messages are shown in "BizTalkMsgBoxDb" in the table "InstancesSuspended" and that the different parts of each message are shown in the table "MessageParts". However I can't find the table where the actual data is stored. Does anyone have any idea where this can be done? Thx

    Read the article

  • Implementing Audit Trail- Spring AOP vs.Hibernate Interceptor vs DB Trigger

    - by RN
    I found couple of discussion threads on this- but nothing which brought a comparison of all three mechanism under one thread. So here is my question... I need to audit DB changes- insert\updates\deletes to business objects. I can think of three ways to do this 1) DB Triggers 2) Hibernate interceptors 3) Spring AOP (This question is specific to a Spring\Hibernate\RDBMS- I guess this is neutral to java\c# or hibernate\nhibernate- but if your answer is dependent upon C++ or Java or specific implementation of hibernate- please specify) What are the pros and cons of selecting one of these strategies ? I am not asking for implementation details.-This is a design discussion. I am hoping we can make this as a part of community wiki

    Read the article

  • Best DataMining Database

    - by Eric
    I am an ocasional Python programer who only have worked so far with MYSQL or SQLITE databases. I am the computer person for everything in a small compamy and I have been started a new project where I think it is about time to try new databases. Sales departament makes a CSV dump every week and I need to make a small scripting application that allow people form other departaments mixing the information, mostly linking the records. I have all this solved, my problem is the speed, I am using just plain text files for all this and unsurprisingly it is very slow. I thought about using mysql, but then I need installing mysql in every desktop, sqlite is easier, but it is very slow. I do not need a full relational database, just some way of play with big amounts of data in a decent time. Many thanks!

    Read the article

  • Is learning the Caché database hard coming from relational databases and object oriented programming

    - by Edelcom
    I am currently running the local version of Caché on my system in order to determine if I can (and will) take on a new possible project. The current project uses Delphi 7 as a front end calling a Caché dll where the business logic is stored in the database. I have a background of Sqlserver and Firebird (and before Access and Paradox) as databases. I use Delphi 7 for 95% of my Windows development, so I know about object programming. I would like to recieve opinions from persons having used Caché and either SqlServer, Firebird or Oracle and having developed in Delphi (or C++ or C# - an object oriented language). I have read the pro's and con's from other questions, but I am not asking for this, I need input from Caché developers. Thanks in advance.

    Read the article

  • .Net opening and clossing database connections

    - by Dan
    I currently designed the data access portion of our framework so that every time a business object needed to interact with the database it would have to open a connection, invoke the data access layer (to execute the query), and then close the connection. Then if it needed to run in a transaction it would open the connection, begin the transaction, invoke the data access layer (to execute the query) and then commit the transaction, close the transaction, and finally close the connection. I did it this way with the mindset of open late and close early...but what if I needed to call other BO's to submit data in a single transaction? Is there a better way to handle opening and closing connections as well as working with transactions? I'm a rookie at architecting applications so I hope I'm not doing this wrong...any help is appreciated.

    Read the article

  • Parametrized Strategy Pattern

    - by ott
    I have several Java classes which implement the strategy pattern. Each class has variable number parameters of different types: interface Strategy { public data execute(data); } class StrategyA implements Strategy { public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, int paramB); public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, String paramB, double paramC); public data execute(data); } Now I want that the user can enter the parameters in some kind of UI. The UI should be chosen at runtime, i.e. the strategies should be independent of it. The parameter dialog should not be monolithic and there should be the possibility to make it behave and look different for each strategy and UI (e.g. console or Swing). How would you solve this problem?

    Read the article

  • Strategy pattern and "action" classes explosion

    - by devoured elysium
    Is it bad policy to have lots of "work" classes(such as Strategy classes), that only do one thing? Let's assume I want to make a Monster class. Instead of just defining everything I want about the monster in one class, I will try to identify what are its main features, so I can define them in interfaces. That will allow to: Seal the class if I want. Later, other users can just create a new class and still have polymorphism by means of the interfaces I've defined. I don't have to worry how people (or myself) might want to change/add features to the base class in the future. All classes inherit from Object and they implement inheritance through interfaces, not from mother classes. Reuse the strategies I'm using with this monster for other members of my game world. Con: This model is rigid. Sometimes we would like to define something that is not easily achieved by just trying to put together this "building blocks". public class AlienMonster : IWalk, IRun, ISwim, IGrowl { IWalkStrategy _walkStrategy; IRunStrategy _runStrategy; ISwimStrategy _swimStrategy; IGrowlStrategy _growlStrategy; public Monster() { _walkStrategy = new FourFootWalkStrategy(); ...etc } public void Walk() { _walkStrategy.Walk(); } ...etc } My idea would be next to make a series of different Strategies that could be used by different monsters. On the other side, some of them could also be used for totally different purposes (i.e., I could have a tank that also "swims"). The only problem I see with this approach is that it could lead to a explosion of pure "method" classes, i.e., Strategy classes that have as only purpose make this or that other action. In the other hand, this kind of "modularity" would allow for high reuse of stratagies, sometimes even in totally different contexts. What is your opinion on this matter? Is this a valid reasoning? Is this over-engineering? Also, assuming we'd make the proper adjustments to the example I gave above, would it be better to define IWalk as: interface IWalk { void Walk(); } or interface IWalk { IWalkStrategy WalkStrategy { get; set; } //or something that ressembles this } being that doing this I wouldn't need to define the methods on Monster itself, I'd just have public getters for IWalkStrategy (this seems to go against the idea that you should encapsulate everything as much as you can!) Why? Thanks

    Read the article

  • How to store the path of a game pawn in a turn based game ?

    - by panzerschreck
    Hello, I have a square grid, for a turn based game ( grid is similar to the chess board ), but the moves in the games are different based on whether you have lapped your opponent pawn at least once or not. i.e if you have not lapped (beaten any of the opponents pawns) in the outer most grid as below if you have lapped your opponent pawn once at least, then you get to reach home,this way.Any player having all his pawns reaching "home" first wins. The ones in yellow are safe-houses, i.e both the opponent pawn and the player's pawn get to stay in the same grid, this is not considered to be lapping ( the opponent ).The lapped pawn will return to its start point. Now the question is, what is the effective way to store the paths for the all the pawns.we will have 4 pawns for the player and 4 opponent pawns. Is there any pattern to store such static information, in a elegant way ? Thanks for your time

    Read the article

  • Concrete Types or Interfaces for return types?

    - by SDReyes
    Today I came to a fundamental paradox of the object programming style, concrete types or interfaces. Whats the better election for a method's return type: a concrete type or an interface? In most cases, I tend to use concrete types as the return type for methods. because I believe that an concrete type is more flexible for further use and exposes more functionality. The dark side of this: Coupling. The angelic one: A concrete type contains per-se the interface you would going to return initially, and extra functionality. What's your thumb's rule? Is there any programming principle for this? BONUS: This is an example of what I mean http://stackoverflow.com/questions/491375/readonlycollection-or-ienumerable-for-exposing-member-collections

    Read the article

  • What makes static initialization functions good, bad, or otherwise?

    - by Richard Levasseur
    Suppose you had code like this: _READERS = None _WRITERS = None def Init(num_readers, reader_params, num_writers, writer_params, ...args...): ...logic... _READERS = new ReaderPool(num_readers, reader_params) _WRITERS = new WriterPool(num_writers, writer_params) ...more logic... class Doer: def __init__(...args...): ... def Read(self, ...args...): c = _READERS.get() try: ...work with conn finally: _READERS.put(c) def Writer(...): ...similar to Read()... To me, this is a bad pattern to follow, some cons: Doers can be created without its preconditions being satisfied The code isn't easily testable because ConnPool can't be directly mocked out. Init has to be called right the first time. If its changed so it can be called multiple times, extra logic has to be added to check if variables are already defined, and lots of NULL values have to be passed around to skip re-initializing. In the event of threads, the above becomes more complicated by adding locking Globals aren't being used to communicate state (which isn't strictly bad, but a code smell) On the other hand, some pros: its very convenient to call Init(5, "user/pass", 2, "user/pass") It simple and "clean" Personally, I think the cons outweigh the pros, that is, testability and assured preconditions outweigh simplicity and convenience.

    Read the article

  • Creating and Indexing Email Database using SqlCe

    - by Anindya Chatterjee
    I am creating a simple email client program. I am using MS SqlCe as a storage of emails. The database schema for storing the message is as follows: StorageId int IDENTITY NOT NULL PRIMARY KEY, FolderName nvarchar(255) NOT NULL, MessageId nvarchar(3999) NOT NULL, MessageDate datetime NOT NULL, StorageData ntext NULL In the StorageData field I am going to store the MIME message as byte array. But the problem arises when I am going to implement search on the stored messages. I have no idea how I am going to index the messages on top of this schema. Can anyone please help me in suggesting a good but simple schema, so that it will be effective in terms of storage space and search friendliness as well? Regards, Anindya Chatterjee

    Read the article

  • SQL 2008 Database tuning advisor won't start

    - by Andrew Hancox
    For some reason I can't get DTA to connect to my development machine. It connects to a remote DB just fine but when I point it to my dev machine I get an error saying: Failed to initialize MSDB database for tuning (exit code: -1073741819). I'm pretty sure it's not a permissions issue since I've used profiler to capture what it's doing and all of the commands it's run so far look fine and are being run under my account which is associated with the sysadmin role, when I run them in sql management studio they go through fine. I'm pretty convinced that the problem is related to creating the objects in MSDB that are used by DTA but I tried creating these manually (I found scripts on the web) and it just seems to push the problem along the line slightly. I'm going out of my mind - have even tried reinstalling SQL but that's not fixed it. I'm using SQL 2008 with SP1 (10.0.2531) on windows server 2008 (patched up to date). SAVE ME!!!!!

    Read the article

  • Create a set column with database migration in rails

    - by Micke
    Hello. I need to add a new column to my users table in the database. I want the type of the column to be set. The column represents the users gender. There should be two options to the set. One form Male "m" and the other for Female "f". But i havent found any doccumentation for adding a column with the set type. How can i do this?

    Read the article

  • ASP MVC Set RadioButton From Database

    - by Jacob Huggart
    Hello All, I have what should be an easy question for you today. I have two radio buttons in my view: Sex: <%=Html.RadioButton("Sex", "Male", true)% Male <%=Html.RadioButton("Sex", "Female", true)% Female I need to select one based on the value returned from my database. The way I am trying to do it now is: ViewData["Sex"] = data.Sex; //Set radio button But that is not working. I have tried every possible combination of isChecked properties. I know that data.Sex is returning either "Male" or "Female". What do I need to do to check the appropriate radio button?

    Read the article

  • Tutorials for .NET database app

    - by ChrisC
    My earlier question and comments are at "What is ADO.NET". This shows my level of knowledge about c# database apps. Can someone point me to tutorials and/or primers that can help me proceed from where I am (also stated in other question)? I've looked and all I've found are tutorials that talk about general db basics (ie, not helping with VS/C#), or talk about connecting to existing SQL db's. I need help setting one up and configuring it, as well as help on how to create and use queries to test the db schema.

    Read the article

  • Open Source Embedded Database Options for .Net Applications

    - by LonnieBest
    I have a .Net 4.0 WPF application that requires an embedded database. MS Access doesn't work on 64 bit Windows I'm told. And I having issues with SSCE: Unable to load DLL 'sqlceme35.dll': This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem. (Exception from HRESULT: 0x800736B1) sqlceme35.dll is installed into my application's program files directory, so I can't seem to figure out why Windows XP Pro doesn't see it. I was wondering about other embedded databases options I might use that work on both 32 and 64 bit windows. Any suggestions?

    Read the article

  • Wondering how Facebook does the "Mutual friends" feature

    - by Pierre
    Hello, I'm currently developing an application to allow students to manage their courses, and I don't really know how to design the database for a specific feature. The client wants, a lot like Facebook, that when a student displays the list of people currently in a specific course, the people with the most mutual courses are displayed first. As an additional feature, I would like to add a search feature to allow students to search for another one, and displaying first in the search results the people with most mutual courses. I currently use MySQL, I plan to use Cassandra for some other features, and I also use Memcached for result caching. Thanks.

    Read the article

  • Example with Visitor Pattern

    - by devoured elysium
    public class Song { public string Genre { get; protected set; } public string Name { get; protected set; } public string Band { get; protected set; } public Song(string name, string band, string genre) { Name = name; Genre = genre; Band = band; } } public interface IMusicVisistor { void Visit(List<Song> items); } public class MusicLibrary { List<Song> _songs = new List<Song> { ...songs ... }; public void Accept(IMusicVisitor visitor) { visitor.Visit(_songs); } } and now here's one Visitor I made: public class RockMusicVisitor : IMusicVisitor { public List<Song> Songs { get; protected set; } public void Visit(List<Song> items) { Songs = items.Where(x => x.Genre == "Rock").ToList(); } } Why is this any better than just putting a public property Songs and then letting any kind of class do with it anything that it wants to? This example comes from this post.

    Read the article

  • Database Version Control SQL Server 2008 Drop SP's and Functions

    - by Lieven Cardoen
    I'm working on versioning our database and now searching for a way to drop all stored procedures and functions from a C# Console Application. I'd rather not create a stored procedure that drops all stored procedures and functions. I has to be some sql executed from C#. I tried to drop the stored procedure before creating it, but I get this message: System.Data.SqlClient.SqlException: 'CREATE/ALTER PROCEDURE' must be the first statement in a query batch. Script for one SP for example: DROP PROCEDURE [dbo].[sp_Economatic_LoadJournalEntryFeedbackByData] SET ANSI_NULLS ON SET QUOTED_IDENTIFIER ON CREATE PROCEDURE [dbo].[sp_Economatic_LoadJournalEntryFeedbackByData] @Data VARCHAR(MAX) AS BEGIN ... END So I guess before creating all SP's and functions I'll need to drop all SP's and functions first with one sql script.

    Read the article

  • Creating colour schemes based on an existing scheme

    - by Neil Barnwell
    I have a colour scheme based around yellow, for warning messages on a website. It amounts to a slightly orange bordered box, with a pale yellow fill. The exact colours are: #FED626 (border) #FFF7C0 (fill) I want to know if it's possible to convert this scheme mathematically or algorithmically somehow, to come up with a blue version where the border is the "same amount" of blue as this one is yellow. Is this possible, or do I just "pin the tail on the donkey" on a colour pallet to get roughly the right one? I ask, because I'd quite like to be able to calculate this on the fly, to perhaps implement something in .less. To give you an idea, I tried swopping the red and blue values on those two, and came up with this: #26D6FE (border) #C0F7FF (fill) That wasn't too hard, but think about if I wanted a pink colour scheme... :)

    Read the article

  • Using Django Admin for a custom database solution

    - by Prashanth Ellina
    A client wants to have a simple intranet application to manage his process. He runs a Quarry and wishes to track number of loads delivered per day and associated activities. Since I knew about Django's excellent Admin interface, I figured I could define the "Schema" in models.py and have Django Admin generate the forms. I did exactly that and the result is not bad at all. I've been able to customize the look and feel to suit the client's taste. Some questions: Is Django Admin the right choice for such a use-case? Will I run to problems in the future due to flexibility of the framework? Is there a better framework out there specifically designed for this use-case (general Database management for small businesses)? I prefer ones written in Python since I can hack it up to customize. Thanks!

    Read the article

  • Are these tables respect the 3NF Database Normalization?

    - by penas
    AUTHOR table Author_ID, PK First_Name Last_Name TITLES table TITLE_ID, PK NAME Author_ID, FK DOMAIN table DOMAIN_ID, PK NAME TITLE_ID, FK READERS table READER_ID, PK First_Name Last_Name ADDRESS CITY_ID, FK PHONE CITY table CITY_ID, PK NAME BORROWING table BORROWING_ID,pk READER_ID, fk TITLE_ID, fk DATE HISTORY table READER_ID TITLE_ID DATE_OF_BORROWING DATE_OF_RETURNING Are these tables respect the 3NF Database Normalization? What if 2 authors work together for the same title? The column Addresss should have it's own table? When a reader borrows a book, I make an entry in BORROWING table. After he returns the book, I delete that entry and I make another one entry in HISTORY table. Is this a good idea? Do I brake any rule? Should I have instead one single BORROWING table with a DATE_OF_RETURNING column?

    Read the article

  • Question regarding factory pattern

    - by eriks
    I have a factory class to build objects of base class B. The object (D) that uses this factory received a list of strings representing the actual types. What is the correct implementation: the factory receives an Enum (and uses switch inside the Create function) and D is responsible to convert the string to Enum. the factory receives a string and checks for a match to a set of valid strings (using ifs') other implementation i didn't think of.

    Read the article

< Previous Page | 119 120 121 122 123 124 125 126 127 128 129 130  | Next Page >