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  • Could these people get arrested? [closed]

    - by Vinicius Horta
    I have seen many of what is called 'private servers' mmorpg (multiplayer online games), which uses stolen sources,modified executable, clients and server. People launch up their own server using VPS or dedicated server and distribute online service among players disclaiming it has educational purposes only, saying they are studying the game engine and selling items for players disclaming it as 'donations', so it seems like they are getting donations to keep studying. We all know it's a comercial method. All of it is copyrighted material from enterprise ABCD. (ABCD = Fictional name, I'm not mentioning names). At their website they include the following: "Private Server XXXX" does not allow/support any conection to any company/organization associated with the game "XXXX". If you are anyway affiliated with enterprise "XXXXXXX", or any other company/organization associated with the game "XXXX" you may not view/open/read/execute/play/download any part of "Private Server XXXX" nor view "Private Server XXXX" website, if any company/organization requests you to investigate our website/server, you may not view "Private SERVER XXXX" or execute any action mentioned above. Any person caught disobeting this disclaimer will be punish to the fulleste extent of law. Can this guys get arrested? Do they disclaimer works? If I'm owner of enterprise X and I know people stole my source and are using them but they have such disclaimer I'm not allowed to investigate them?

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  • Delay command execution over sockets

    - by David
    I've been trying to fix the game loop in a real time (tick delay) MUD. I realized using Thread.Sleep would seem clunky when the user spammed commands through their choice of client (Zmud, etc) e.g. east;south;southwest would wait three move ticks and then output everything from the past couple rooms. The game loop basically calls a Flush and Fill method for each socket during each tick (50ms) private void DoLoop() { Stopwatch stopWatch = new Stopwatch(); stopWatch.Start(); while (running) { // for each socket, flush and fill ConnectionMonitor.Update(); stopWatch.Stop(); WaitIfNeeded(stopWatch.ElapsedMilliseconds); stopWatch.Reset(); } } The Fill method fires the command events, but as mentioned before, they currently block using Thread.Sleep. I tried adding a "ready" flag to the state object that attempts to execute the command along with a queue of spammed commands, but it ends up executing one command and queuing up the rest i.e. each subsequent command executes something that got queued up that should've been executed before. I must be missing something about the timer. private readonly Queue<SpammedCommand> queuedCommands = new Queue<SpammedCommand>(); private bool ready = true; private void TryExecuteCommand(string input) { var commandContext = CommandContext.Create(input); var player = Server.Current.Database.Get<Player>(Session.Player.Key); var commandInfo = Server.Current.CommandLookup .FindCommand(commandContext.CommandName, player.IsAdmin); if (commandInfo != null) { if (!ready) { // queue command queuedCommands.Enqueue(new SpammedCommand() { Context = commandContext, Info = commandInfo }); return; } if (queuedCommands.Count > 0) { // queue the incoming command queuedCommands.Enqueue(new SpammedCommand() { Context = commandContext, Info = commandInfo, }); // dequeue and execute var command = queuedCommands.Dequeue(); command.Info.Command.Execute(Session, command.Context); setTimeout(command.Info.TickLength); return; } commandInfo.Command.Execute(Session, commandContext); setTimeout(commandInfo.TickLength); } else { Session.WriteLine("Command not recognized"); } } Finally, setTimeout was supposed to set the execution delay (TickLength) for that command, and makeReady just sets the ready flag on the state object to true. private void setTimeout(TickDelay tickDelay) { ready = false; var t = new System.Timers.Timer() { Interval = (long) tickDelay, AutoReset = false, }; t.Elapsed += makeReady; t.Start(); // fire this in tickDelay ms } // MAKE READYYYYY!!!! private void makeReady(object sender, System.Timers.ElapsedEventArgs e) { ready = true; } Am I missing something about the System.Timers.Timer created in setTimeout? How can I execute (and output) spammed commands per TickLength without using Thread.Sleep?

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  • Is it appropriate to try to control the order of finalization?

    - by Strilanc
    I'm writing a class which is roughly analogous to a CancellationToken, except it has a third state for "never going to be cancelled". At the moment I'm trying to decide what to do if the 'source' of the token is garbage collected without ever being set. It seems that, intuitively, the source should transition the associated token to the 'never cancelled' state when it is about to be collected. However, this could trigger callbacks who were only kept alive by their linkage from the token. That means what those callbacks reference might now in the process of finalization. Calling them would be bad. In order to "fix" this, I wrote this class: public sealed class GCRoot { private static readonly GCRoot MainRoot = new GCRoot(); private GCRoot _next; private GCRoot _prev; private object _value; private GCRoot() { this._next = this._prev = this; } private GCRoot(GCRoot prev, object value) { this._value = value; this._prev = prev; this._next = prev._next; _prev._next = this; _next._prev = this; } public static GCRoot Root(object value) { return new GCRoot(MainRoot, value); } public void Unroot() { lock (MainRoot) { _next._prev = _prev; _prev._next = _next; this._next = this._prev = this; } } } intending to use it like this: Source() { ... _root = GCRoot.Root(callbacks); } void TransitionToNeverCancelled() { _root.Unlink(); ... } ~Source() { TransitionToNeverCancelled(); } but now I'm troubled. This seems to open the possibility for memory leaks, without actually fixing all cases of sources in limbo. Like, if a source is closed over in one of its own callbacks, then it is rooted by the callback root and so can never be collected. Presumably I should just let my sources be collected without a peep. Or maybe not? Is it ever appropriate to try to control the order of finalization, or is it a giant warning sign?

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  • Creating deterministic key pairs in javascript for use in encrypting/decrypting/signing messages

    - by SlickTheNick
    So I have been searching everywhere and havn't been able to find anything with the sufficient information I need.. so Im a bit stumped on this one at the moment What I am trying to do is create a public/private key pair (like PGP) upon a users account creation, based on their passphrase and a random seed. The public key would be saved on the server, and ideally the private key would never be seen by the server whatsoever. The user could then sign in, and send a message to another user. Before the message is sent, the senders key pair would be re-generated on the fly based on their credentials (and maybe a password prompt) and used to encrypt the message. The receiver would then use their own re-generated private key to decrypt said message. The server itself should never see any plaintext passwords, private keys or readable messages. Bit unsure how on how I could go about implementing this. Iv been looking into PGP, specifically openPGP.js. The main trouble I am having is being able to regenerate the key-pair based off a specific seed. PGP seems to have a random output even if the inputs are the same. Storing the private key in a cookie or in HTML5 storage or something also isnt really an option, too unreliable. Can anyone point me in the right direction?

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  • How do I make my character slide down high-angled slopes?

    - by keinabel
    I am currently working on my character's movement in Unity3D. I managed to make him move relatively to the mouse cursor. I set a slope limit of 45°, which does not allow the character to walk up the mountains with higher degrees. But he can still jump them up. How do I manage to make him slide down again when he jumped at places with too high slope? Thanks in advance. edit: Code snippet of my basic movement. using UnityEngine; using System.Collections; public class BasicMovement : MonoBehaviour { private float speed; private float jumpSpeed; private float gravity; private float slopeLimit; private Vector3 moveDirection = Vector3.zero; void Start() { PlayerSettings settings = GetComponent<PlayerSettings>(); speed = settings.GetSpeed(); jumpSpeed = settings.GetJumpSpeed(); gravity = settings.GetGravity(); slopeLimit = settings.GetSlopeLimit(); } void Update() { CharacterController controller = GetComponent<CharacterController>(); controller.slopeLimit = slopeLimit; if (controller.isGrounded) { moveDirection = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical")); moveDirection = transform.TransformDirection(moveDirection); moveDirection *= speed; if (Input.GetButton("Jump")) { moveDirection.y = jumpSpeed; } } moveDirection.y -= gravity * Time.deltaTime; controller.Move(moveDirection * Time.deltaTime); } }

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  • Is this a pattern? Should it be?

    - by Arkadiy
    The following is more of a statement than a question - it describes something that may be a pattern. The question is: is this a known pattern? Or, if it's not, should it be? I've had a situation where I had to iterate over two dissimilar multi-layer data structures and copy information from one to the other. Depending on particular use case, I had around eight different kinds of layers, combined in about eight different combinations: A-B-C B-C A-C D-E A-D-E and so on After a few unsuccessful attempts to factor out the repetition of per-layer iteration code, I realized that the key difficulty in this refactoring was the fact that the bottom level needed access to data gathered at higher levels. To explicitly accommodate this requirement, I introduced IterationContext class with a number of get() and set() methods for accumulating the necessary information. In the end, I had the following class structure: class Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const = 0; }; class RecursingIterator : public Iterator { RecursingIterator(const Iterator &below); }; class IterateOverA : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // Iterate over members in dataStructure1 // locate corresponding item in dataStructure2 (passed via context) // and set it in the context // invoke the sub-iterator }; class IterateOverB : public RecursingIterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // iterate over members dataStructure2 (form context) // set dataStructure2's item in the context // locate corresponding item in dataStructure2 (passed via context) // invoke the sub-iterator }; void main() { class FinalCopy : public Iterator { virtual void iterateOver(const Structure &dataStructure1, IterationContext &ctx) const { // copy data from structure 1 to structure 2 in the context, // using some data from higher levels as needed } } IterationContext ctx(dateStructure2); IterateOverA(IterateOverB(FinalCopy())).iterate(dataStructure1, ctx); } It so happens that dataStructure1 is a uniform data structure, similar to XML DOM in that respect, while dataStructure2 is a legacy data structure made of various structs and arrays. This allows me to pass dataStructure1 outside of the context for convenience. In general, either side of the iteration or both sides may be passed via context, as convenient. The key situation points are: complicated code that needs to be invoked in "layers", with multiple combinations of layer types possible at the bottom layer, the information from top layers needs to be visible. The key implementation points are: use of context class to access the data from all levels of iteration complicated iteration code encapsulated in implementation of pure virtual function two interfaces - one aware of underlying iterator, one not aware of it. use of const & to simplify the usage syntax.

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  • How to dynamically override a method in an object

    - by Ace Takwas
    If this is possible, how can I change what a method does after I might have created an instance of that class and wish to keep the reference to that object but override a public method in it's class' definition? Here's my code: package time_applet; public class TimerGroup implements Runnable{ private Timer hour, min, sec; private Thread hourThread, minThread, secThread; public TimerGroup(){ hour = new HourTimer(); min = new MinuteTimer(); sec = new SecondTimer(); } public void run(){ hourThread.start(); minThread.start(); secThread.start(); } /*Please pay close attention to this method*/ private Timer activateHourTimer(int start_time){ hour = new HourTimer(start_time){ public void run(){ while (true){ if(min.changed)//min.getTime() == 0) changeTime(); } } }; hourThread = new Thread(hour); return hour; } private Timer activateMinuteTimer(int start_time){ min = new MinuteTimer(start_time){ public void run(){ while (true){ if(sec.changed)//sec.getTime() == 0) changeTime(); } } }; minThread = new Thread(min); return min; } private Timer activateSecondTimer(int start_time){ sec = new SecondTimer(start_time); secThread = new Thread(sec); return sec; } public Timer addTimer(Timer timer){ if (timer instanceof HourTimer){ hour = timer; return activateHourTimer(timer.getTime()); } else if (timer instanceof MinuteTimer){ min = timer; return activateMinuteTimer(timer.getTime()); } else{ sec = timer; return activateSecondTimer(timer.getTime()); } } } So for example in the method activateHourTimer(), I would like to override the run() method of the hour object without having to create a new object. How do I go about that?

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  • The term "interface" in C++

    - by Flexo
    Java makes a clear distinction between class and interface. (I believe C# does also, but I have no experience with it). When writing C++ however there is no language enforced distinction between class and interface. Consequently I've always viewed interface as a workaround for the lack of multiple inheritance in Java. Making such a distinction feels arbitrary and meaningless in C++. I've always tended to go with the "write things in the most obvious way" approach, so if in C++ I've got what might be called an interface in Java, e.g.: class Foo { public: virtual void doStuff() = 0; ~Foo() = 0; }; and I then decided that most implementers of Foo wanted to share some common functionality I would probably write: class Foo { public: virtual void doStuff() = 0; ~Foo() {} protected: // If it needs this to do its thing: int internalHelperThing(int); // Or if it doesn't need the this pointer: static int someOtherHelper(int); }; Which then makes this not an interface in the Java sense anymore. Instead C++ has two important concepts, related to the same underlying inheritance problem: virtual inhertiance Classes with no member variables can occupy no extra space when used as a base "Base class subobjects may have zero size" Reference Of those I try to avoid #1 wherever possible - it's rare to encounter a scenario where that genuinely is the "cleanest" design. #2 is however a subtle, but important difference between my understanding of the term "interface" and the C++ language features. As a result of this I currently (almost) never refer to things as "interfaces" in C++ and talk in terms of base classes and their sizes. I would say that in the context of C++ "interface" is a misnomer. It has come to my attention though that not many people make such a distinction. Do I stand to lose anything by allowing (e.g. protected) non-virtual functions to exist within an "interface" in C++? (My feeling is the exactly the opposite - a more natural location for shared code) Is the term "interface" meaningful in C++ - does it imply only pure virtual or would it be fair to call C++ classes with no member variables an interface still?

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  • Android question - how to prep 100 images to be shown via Fling/Swipe?

    - by fooyee
    I'm totally new to this, been tinkering around for a week. Came up with a simple image viewer app for 2 images. Feature: Left and right swipes will switch the images. Dead simple. What i'd like to do: Have up to 100 images. note: All my images are in my res/drawable folder. They're named image1.png to image100.png I obviously don't want to do: ImageView i = new ImageView(this); i.setImageResource(R.drawable.image1); viewFlipper.addView(i); ImageView i2 = new ImageView(this); i2.setImageResource(R.drawable.image2); viewFlipper.addView(i2); ImageView i3 = new ImageView(this); i3.setImageResource(R.drawable.image3); viewFlipper.addView(i3); all the way to i100. how do I make this into a loop, which is flexible and reads everything from the drawable folder ( and not be limited to 100 images)? source: public class ImageViewTest extends Activity { private static final String LOGID = "CHECKTHISOUT"; private static final int SWIPE_MIN_DISTANCE = 120; private static final int SWIPE_MAX_OFF_PATH = 250; private static final int SWIPE_THRESHOLD_VELOCITY = 200; private GestureDetector gestureDetector; View.OnTouchListener gestureListener; private Animation slideLeftIn; private Animation slideLeftOut; private Animation slideRightIn; private Animation slideRightOut; private ViewFlipper viewFlipper; String message = "Initial Message"; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); //Set up viewflipper viewFlipper = new ViewFlipper(this); ImageView i = new ImageView(this); i.setImageResource(R.drawable.sample_1); ImageView i2 = new ImageView(this); i2.setImageResource(R.drawable.sample_2); viewFlipper.addView(i); viewFlipper.addView(i2); //set up animations slideLeftIn = AnimationUtils.loadAnimation(this, R.anim.slide_left_in); slideLeftOut = AnimationUtils.loadAnimation(this, R.anim.slide_left_out); slideRightIn = AnimationUtils.loadAnimation(this, R.anim.slide_right_in); slideRightOut = AnimationUtils.loadAnimation(this, R.anim.slide_right_out); //put up a brownie as a starter setContentView(viewFlipper); gestureDetector = new GestureDetector(new MyGestureDetector()); } public class MyGestureDetector extends SimpleOnGestureListener { @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { try { if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH) return false; // right to left swipe if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) { Log.v(LOGID,"right to left swipe detected"); viewFlipper.setInAnimation(slideLeftIn); viewFlipper.setOutAnimation(slideLeftOut); viewFlipper.showNext(); setContentView(viewFlipper); } // left to right swipe else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) { Log.v(LOGID,"left to right swipe detected"); viewFlipper.setInAnimation(slideRightIn); viewFlipper.setOutAnimation(slideRightOut); viewFlipper.showPrevious(); setContentView(viewFlipper); } } catch (Exception e) { // nothing } return false; } } // This doesn't work @Override public boolean onTouchEvent(MotionEvent event) { if (gestureDetector.onTouchEvent(event)){ Log.v(LOGID,"screen touched"); return true; } else{ return false; } } }

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  • how to do android image animation

    - by user270811
    hi, i am trying to get a simple image animation going. i want to make it looks as if the helicopter's propeller blades are turning. i have 3 images for the helicopter, and i am showing one of these images depending on the animation progress. the problem is that all three images end up overlapping each other as opposed to just one image showing up at one time, thereby creating the animation. this is what i did so far, i even tried to clear canvas by doing this canvas.drawColor(Color.BLACK), but that would clear out the whole canvas, which is not what i want. this is what i have: 1) in the View class: static class Helicopter { private long mLastUpdate; private long mProgress = 0; private final float mX; private final float mY; private final Bitmap mHelicopter1; private final Bitmap mHelicopter2; private final Bitmap mHelicopter3; private final float mRadius; Helicopter(long mLastUpdate, float mX, float mY, Bitmap helicopter1, Bitmap helicopter2, Bitmap helicopter3) { this.mLastUpdate = mLastUpdate; this.mX = mX; this.mY = mY; this.mHelicopter1 = helicopter1; this.mHelicopter2 = helicopter2; this.mHelicopter3 = helicopter3; mRadius = ((float) mHelicopter1.getWidth()) / 2f; } public void update(long now) { mProgress += (now - mLastUpdate); if(mProgress >= 400L) { mProgress = 0; } mLastUpdate = now; } public void setNow(long now) { mLastUpdate = now; } public void draw(Canvas canvas, Paint paint) { if (mProgress < 150L) { canvas.drawBitmap(mHelicopter1, mX - mRadius, mY - mRadius, paint); } else if (mProgress < 300L) { canvas.drawBitmap(mHelicopter2, mX - mRadius, mY - mRadius, paint); } else if(mProgress < 400L) { canvas.drawBitmap(mHelicopter3, mX - mRadius, mY - mRadius, paint); } } public boolean done() { return mProgress > 700L; } } private ArrayList<Helicopter> mHelicopters = new ArrayList<Helicopter>(); 2) this is being called in the run() of a thread: private void doDraw(Canvas canvas) { final long now = SystemClock.elapsedRealtime(); canvas.save(); for (int i = 0; i < mHelicopters.size(); i++) { final Helicopter explosion = mHelicopters.get(i); explosion.update(now); } for (int i = 0; i < mHelicopters.size(); i++) { final Helicopter explosion = mHelicopters.get(i); explosion.draw(canvas, mPaint); } canvas.restore(); } can someone help me? i have looked at a lot of the examples on the web on animation, they seem to always involve text, but not images. thanks.

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  • Delay in displaying contents in JDialog

    - by Yohan
    Please have a look at the following code import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.util.List; import java.util.ArrayList; public class SendEmailForm extends JDialog { private JLabel to, cc, bcc, subject, account; private JTextField toTxt, ccTxt, bccTxt, subjectTxt; private JTextArea messageTxt; private JButton send; private JComboBox accountBox; private JScrollPane scroll; private GridBagLayout gbl; private GridBagConstraints gbc; public SendEmailForm() { //Declaring instance variables to = new JLabel("To: "); cc = new JLabel("CC: "); bcc = new JLabel("BCC: "); subject = new JLabel("Subject: "); account = new JLabel("Select an Account: "); toTxt = new JTextField(20); ccTxt = new JTextField(20); bccTxt = new JTextField(20); subjectTxt = new JTextField(20); messageTxt = new JTextArea(20, 50); messageTxt.setLineWrap(true); scroll = new JScrollPane(messageTxt); scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED); scroll.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); accountBox = new JComboBox(); accountBox.addItem("Yahoo"); accountBox.addItem("GMail"); accountBox.addItem("MSN"); //accountBox.addItem("Yahoo"); //accountBox.addItem("Yahoo"); JPanel buttonPanel = new JPanel(); buttonPanel.setLayout(new FlowLayout()); send = new JButton("Send"); send.addActionListener(new SendButtonAction()); buttonPanel.add(send); //Creating thr GUI //GUI CREATION IS REMOVED IN THIS POST this.setTitle("Send Emails"); this.setVisible(true); this.pack(); this.setLocationRelativeTo(null); this.validate(); } private class SendButtonAction implements ActionListener { public void actionPerformed(ActionEvent ae) { ProgressMonitor pm = new ProgressMonitor(); //Retreiving the user name and password List userData = new ArrayList(); EmailDBConnector emailCon = new EmailDBHandler(); userData = emailCon.getUserNameAndPassword( accountBox.getSelectedItem().toString().trim()); String userName = userData.get(0).toString(); String password = userData.get(1).toString(); System.out.println(userName); System.out.println(password); pm.setVisible(true); SendEmail sendEmail = new SendEmail(toTxt.getText(), userName.trim(), bccTxt.getText(), ccTxt.getText(), accountBox.getSelectedItem().toString().trim(), messageTxt.getText().trim(), password.trim(), subjectTxt.getText()); String result = sendEmail.send(); //pm.dispose(); JOptionPane.showMessageDialog(null, result); } } private class ProgressMonitor extends JDialog { public ProgressMonitor() { this.setLayout(new BorderLayout()); JLabel text = new JLabel("Sending..Please wait..."); this.add(text, "Center"); this.pack(); this.validate(); this.setLocationRelativeTo(null); } } } First, this is an email program. In here, when the JDialog is called, it just opens as a 100% blank window. I have added a JLabel, but it is not there when it is displaying. Anyway, it takes sometime to send the email, after the email is sent, I can see the JLabel in the JDialog. If I take my issue into one sentence, I am calling the JDialog before the email is sent, but it appears blank, after the email is sent, it's content are there! Why is this? Please help!

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  • java will this threading setup work or what can i be doing wrong

    - by Erik
    Im a bit unsure and have to get advice. I have the: public class MyApp extends JFrame{ And from there i do; MyServer = new MyServer (this); MyServer.execute(); MyServer is a: public class MyServer extends SwingWorker<String, Object> { MyServer is doing listen_socket.accept() in the doInBackground() and on connection it create a new class Connection implements Runnable { I have the belove DbHelper that are a singleton. It holds an Sqlite connected. Im initiating it in the above MyApp and passing references all the way in to my runnable: class Connection implements Runnable { My question is what will happen if there are two simultaneous read or `write? My thought here was the all methods in the singleton are synchronized and would put all calls in the queue waiting to get a lock on the synchronized method. Will this work or what can i change? public final class DbHelper { private boolean initalized = false; private String HomePath = ""; private File DBFile; private static final String SYSTEM_TABLE = "systemtable"; Connection con = null; private Statement stmt; private static final ContentProviderHelper instance = new ContentProviderHelper (); public static ContentProviderHelper getInstance() { return instance; } private DbHelper () { if (!initalized) { initDB(); initalized = true; } } private void initDB() { DBFile = locateDBFile(); try { Class.forName("org.sqlite.JDBC"); // create a database connection con = DriverManager.getConnection("jdbc:sqlite:J:/workspace/workComputer/user_ptpp"); } catch (SQLException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } private File locateDBFile() { File f = null; try{ HomePath = System.getProperty("user.dir"); System.out.println("HomePath: " + HomePath); f = new File(HomePath + "/user_ptpp"); if (f.canRead()) return f; else { boolean success = f.createNewFile(); if (success) { System.out.println("File did not exist and was created " + HomePath); // File did not exist and was created } else { System.out.println("File already exists " + HomePath); // File already exists } } } catch (IOException e) { System.out.println("Maybe try a new directory. " + HomePath); //Maybe try a new directory. } return f; } public String getHomePath() { return HomePath; } private synchronized String getDate(){ SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Date date = new Date(); return dateFormat.format(date); } public synchronized String getSelectedSystemTableColumn( String column) { String query = "select "+ column + " from " + SYSTEM_TABLE ; try { stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY); ResultSet rs = stmt.executeQuery(query); while (rs.next()) { String value = rs.getString(column); if(value == null || value == "") return ""; else return value; } } catch (SQLException e ) { e.printStackTrace(); return ""; } finally { } return ""; } }

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  • Performance issues in android game

    - by user1446632
    I am making an android game, but however, the game is functioning like it should, but i am experiencing some performance issues. I think it has something to do with the sound. Cause each time i touch the screen, it makes a sound. I am using the standard MediaPlayer. The method is onTouchEvent() and onPlaySound1(). Could you please help me with an alternate solution for playing the sound? Thank you so much in advance! It would be nice if you also came up with some suggestions on how i can improve my code. Take a look at my code here: package com.mycompany.mygame; import java.util.ArrayList; import android.content.Context; import android.content.Intent; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.media.MediaPlayer; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.View; import android.webkit.WebView; import android.widget.TextView; import android.widget.Toast; public class ExampleView extends SurfaceView implements SurfaceHolder.Callback { class ExampleThread extends Thread { private ArrayList<Parachuter> parachuters; private Bitmap parachuter; private Bitmap background; private Paint black; private boolean running; private SurfaceHolder mSurfaceHolder; private Context mContext; private Context mContext1; private Handler mHandler; private Handler mHandler1; private GameScreenActivity mActivity; private long frameRate; private boolean loading; public float x; public float y; public float x1; public float y1; public MediaPlayer mp1; public MediaPlayer mp2; public int parachuterIndexToResetAndDelete; public int canvasGetWidth; public int canvasGetWidth1; public int canvasGetHeight; public int livesLeftValue; public int levelValue = 1; public int levelValue1; public int parachutersDown; public int difficultySet; public boolean isSpecialAttackAvailible; public ExampleThread(SurfaceHolder sHolder, Context context, Handler handler) { mSurfaceHolder = sHolder; mHandler = handler; mHandler1 = handler; mContext = context; mActivity = (GameScreenActivity) context; parachuters = new ArrayList<Parachuter>(); parachuter = BitmapFactory.decodeResource(getResources(), R.drawable.parachuteman); black = new Paint(); black.setStyle(Paint.Style.FILL); black.setColor(Color.GRAY); background = BitmapFactory.decodeResource(getResources(), R.drawable.gamescreenbackground); running = true; // This equates to 26 frames per second. frameRate = (long) (1000 / 26); loading = true; mp1 = MediaPlayer.create(getContext(), R.raw.bombsound); } @Override public void run() { while (running) { Canvas c = null; try { c = mSurfaceHolder.lockCanvas(); synchronized (mSurfaceHolder) { long start = System.currentTimeMillis(); doDraw(c); long diff = System.currentTimeMillis() - start; if (diff < frameRate) Thread.sleep(frameRate - diff); } } catch (InterruptedException e) { } finally { if (c != null) { mSurfaceHolder.unlockCanvasAndPost(c); } } } } protected void doDraw(Canvas canvas) { canvas.drawRect(0, 0, canvas.getWidth(), canvas.getHeight(), black); //Draw for (int i = 0; i < parachuters.size(); i++) { canvas.drawBitmap(parachuter, parachuters.get(i).getX(), parachuters.get(i).getY(), null); parachuters.get(i).tick(); } //Remove for (int i = 0; i < parachuters.size(); i++) { if (parachuters.get(i).getY() > canvas.getHeight()) { parachuters.remove(i); onPlaySound(); checkLivesLeftValue(); checkAmountOfParachuters(); } else if(parachuters.get(i).isTouched()) { parachuters.remove(i); } else{ //Do nothing } } } public void loadBackground(Canvas canvas) { //Load background canvas.drawBitmap(background, 0, 0, black); } public void checkAmountOfParachuters() { mHandler.post(new Runnable() { @Override public void run() { if(parachuters.isEmpty()) { levelValue = levelValue + 1; Toast.makeText(getContext(), "New level! " + levelValue, 15).show(); if (levelValue == 3) { drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); drawParachutersGroup4(); } else if (levelValue == 5) { drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); drawParachutersGroup4(); drawParachutersGroup5(); } else if (levelValue == 7) { drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); drawParachutersGroup4(); drawParachutersGroup5(); drawParachutersGroup6(); } else if (levelValue == 9) { //Draw 7 groups of parachuters drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); drawParachutersGroup4(); drawParachutersGroup5(); drawParachutersGroup6(); drawParachutersGroup1(); } else if (levelValue > 9) { //Draw 7 groups of parachuters drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); drawParachutersGroup4(); drawParachutersGroup5(); drawParachutersGroup6(); drawParachutersGroup1(); } else { //Draw normal 3 groups of parachuters drawParachutersGroup1(); drawParachutersGroup2(); drawParachutersGroup3(); } } else { //Do nothing } } }); } private void checkLivesLeftValue() { mHandler.post(new Runnable() { @Override public void run() { Log.d("checkLivesLeftValue", "lives = " + livesLeftValue); // TODO Auto-generated method stub if (livesLeftValue == 3) { //Message to display: "You lost! Log.d("checkLivesLeftValue", "calling onMethod now"); parachuters.removeAll(parachuters); onMethod(); } else if (livesLeftValue == 2) { Toast.makeText(getContext(), "Lives left=1", 15).show(); livesLeftValue = livesLeftValue + 1; Log.d("checkLivesLeftValue", "increased lives to " + livesLeftValue); } else if (livesLeftValue == 1) { Toast.makeText(getContext(), "Lives left=2", 15).show(); livesLeftValue = livesLeftValue + 1; Log.d("checkLivesLeftValue", "increased lives to " + livesLeftValue); } else { //Set livesLeftValueText 3 Toast.makeText(getContext(), "Lives left=3", 15).show(); livesLeftValue = livesLeftValue + 1; Log.d("checkLivesLeftValue", "increased lives to " + livesLeftValue); } } }); } public void onMethod() { mHandler.post(new Runnable() { @Override public void run() { try { Toast.makeText(getContext(), "You lost!", 15).show(); livesLeftValue = 0; //Tell the user that he lost: android.content.Context ctx = mContext; Intent i = new Intent(ctx, playerLostMessageActivity.class); i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); i.putExtra("KEY","You got to level " + levelValue + " And you shot down " + parachutersDown + " parachuters"); i.putExtra("levelValue", levelValue); ctx.startActivity(i); System.exit(0); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); //Exit activity and start playerLostMessageActivity Toast.makeText(getContext(), "You lost!", 15).show(); livesLeftValue = 0; //Tell the user that he lost: android.content.Context ctx = mContext; Intent i = new Intent(ctx, playerLostMessageActivity.class); i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); i.putExtra("KEY","You got to level " + levelValue + " And you shot down " + parachutersDown + " parachuters"); i.putExtra("levelValue", levelValue); System.exit(0); ctx.startActivity(i); System.exit(0); } } }); } public void onPlaySound() { try { mp1.start(); } catch (Exception e) { e.printStackTrace(); mp1.release(); } } public void onDestroy() { try { parachuters.removeAll(parachuters); mp1.stop(); mp1.release(); } catch (Exception e) { e.printStackTrace(); } } public void onPlaySound1() { try { mp2 = MediaPlayer.create(getContext(), R.raw.airriflesoundeffect); mp2.start(); } catch (Exception e) { e.printStackTrace(); mp2.release(); } } public boolean onTouchEvent(MotionEvent event) { if (event.getAction() != MotionEvent.ACTION_DOWN) releaseMediaPlayer(); x1 = event.getX(); y1 = event.getY(); checkAmountOfParachuters(); removeParachuter(); return false; } public void releaseMediaPlayer() { try { mp1.release(); } catch (Exception e) { e.printStackTrace(); } } public void removeParachuter() { try { for (Parachuter p: parachuters) { if (x1 > p.getX() && x1 < p.getX() + parachuter.getWidth() && y1 > p.getY() && y1 < p.getY() + parachuter.getHeight()) { p.setTouched(true); onPlaySound1(); parachutersDown = parachutersDown + 1; p.setTouched(false); } } } catch (Exception e) { e.printStackTrace(); } } public void initiateDrawParachuters() { drawParachutersGroup1(); } public void drawParachutersGroup1() { // TODO Auto-generated method stub //Parachuter group nr. 1 //Parachuter nr. 2 x = 75; y = 77; Parachuter p1 = new Parachuter(x, y); parachuters.add(p1); //Parachuter nr.1 x = 14; y = 28; Parachuter p = new Parachuter(x, y); parachuters.add(p); //Parachuter nr. 3 x = 250; y = 94; Parachuter p3 = new Parachuter(x, y); parachuters.add(p3); //Parachuter nr. 3 x = 275; y = 80; Parachuter p2 = new Parachuter(x, y); parachuters.add(p2); //Parachuter nr. 5 x = 280; y = 163; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 125; y = 118; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 126; y = 247; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 123; y = 77; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachutersGroup2() { // TODO Auto-generated method stub //Parachuter group nr. 2 //Parachuter nr. 5 x = 153; y = 166; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 133; y = 123; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 170; y = 213; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 190; y = 121; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachutersGroup3() { // TODO Auto-generated method stub //Parachuter group nr. 3 //Parachuter nr. 2 x = 267; y = 115; Parachuter p1 = new Parachuter(x, y); parachuters.add(p1); //Parachuter nr.1 x = 255; y = 183; Parachuter p = new Parachuter(x, y); parachuters.add(p); //Parachuter nr. 3 x = 170; y = 280; Parachuter p3 = new Parachuter(x, y); parachuters.add(p3); //Parachuter nr. 3 x = 116; y = 80; Parachuter p2 = new Parachuter(x, y); parachuters.add(p2); //Parachuter nr. 5 x = 67; y = 112; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 260; y = 89; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 260; y = 113; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 178; y = 25; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachutersGroup4() { // TODO Auto-generated method stub //Parachuter group nr. 1 //Parachuter nr. 2 x = 75; y = 166; Parachuter p1 = new Parachuter(x, y); parachuters.add(p1); //Parachuter nr.1 x = 118; y = 94; Parachuter p = new Parachuter(x, y); parachuters.add(p); //Parachuter nr. 3 x = 38; y = 55; Parachuter p3 = new Parachuter(x, y); parachuters.add(p3); //Parachuter nr. 3 x = 57; y = 18; Parachuter p2 = new Parachuter(x, y); parachuters.add(p2); //Parachuter nr. 5 x = 67; y = 119; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 217; y = 113; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 245; y = 234; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 239; y = 44; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachutersGroup5() { // TODO Auto-generated method stub //Parachuter group nr. 1 //Parachuter nr. 2 x = 59; y = 120; Parachuter p1 = new Parachuter(x, y); parachuters.add(p1); //Parachuter nr.1 x = 210; y = 169; Parachuter p = new Parachuter(x, y); parachuters.add(p); //Parachuter nr. 3 x = 199; y = 138; Parachuter p3 = new Parachuter(x, y); parachuters.add(p3); //Parachuter nr. 3 x = 22; y = 307; Parachuter p2 = new Parachuter(x, y); parachuters.add(p2); //Parachuter nr. 5 x = 195; y = 22; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 157; y = 132; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 150; y = 183; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 130; y = 20; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachutersGroup6() { // TODO Auto-generated method stub //Parachuter group nr. 1 //Parachuter nr. 2 x = 10; y = 10; Parachuter p1 = new Parachuter(x, y); parachuters.add(p1); //Parachuter nr.1 x = 20; y = 20; Parachuter p = new Parachuter(x, y); parachuters.add(p); //Parachuter nr. 3 x = 30; y = 30; Parachuter p3 = new Parachuter(x, y); parachuters.add(p3); //Parachuter nr. 3 x = 60; y = 60; Parachuter p2 = new Parachuter(x, y); parachuters.add(p2); //Parachuter nr. 5 x = 90; y = 90; Parachuter p5 = new Parachuter(x, y); parachuters.add(p5); x = 120; y = 120; Parachuter p4 = new Parachuter(x, y); parachuters.add(p4); //Parachuter nr. 7 x = 150; y = 150; Parachuter p7 = new Parachuter(x, y); parachuters.add(p7); //Parachuter nr. 6 x = 180; y = 180; Parachuter p6 = new Parachuter(x, y); parachuters.add(p6); } public void drawParachuters() { Parachuter p = new Parachuter(x, y); parachuters.add(p); Toast.makeText(getContext(), "x=" + x + " y=" + y, 15).show(); } public void setRunning(boolean bRun) { running = bRun; } public boolean getRunning() { return running; } } /** Handle to the application context, used to e.g. fetch Drawables. */ private Context mContext; /** Pointer to the text view to display "Paused.." etc. */ private TextView mStatusText; /** The thread that actually draws the animation */ private ExampleThread eThread; public ExampleView(Context context) { super(context); // register our interest in hearing about changes to our surface SurfaceHolder holder = getHolder(); holder.addCallback(this); // create thread only; it's started in surfaceCreated() eThread = new ExampleThread(holder, context, new Handler() { @Override public void handleMessage(Message m) { // mStatusText.setVisibility(m.getData().getInt("viz")); // mStatusText.setText(m.getData().getString("text")); } }); setFocusable(true); } @Override public boolean onTouchEvent(MotionEvent event) { return eThread.onTouchEvent(event); } public ExampleThread getThread() { return eThread; } @Override public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) { // TODO Auto-generated method stub } public void surfaceCreated(SurfaceHolder holder) { if (eThread.getState() == Thread.State.TERMINATED) { eThread = new ExampleThread(getHolder(), getContext(), getHandler()); eThread.start(); } else { eThread.start(); } } @Override public void surfaceDestroyed(SurfaceHolder holder) { boolean retry = true; eThread.setRunning(false); while (retry) { try { eThread.join(); retry = false; } catch (InterruptedException e) { } } } }

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  • Fluent NHibernate Mapping and Formulas/DatePart

    - by Alessandro Di Lello
    Hi There, i have a very simple table with a Datetime column and i have this mapping in my domain object. MyDate is the name of the datetime column in the DB. public virtual int Day { get; set; } public virtual int Month { get; set; } public virtual int Year { get; set; } public virtual int Hour { get; set; } public virtual int Minutes { get; set; } public virtual int Seconds { get;set; } public virtual int WeekNo { get; set; } Map(x => x.Day).Formula("DATEPART(day, Datetime)"); Map(x => x.Month).Formula("DATEPART(month, Datetime)"); Map(x => x.Year).Formula("DATEPART(year, Datetime)"); Map(x => x.Hour).Formula("DATEPART(hour, Datetime)"); Map(x => x.Minutes).Formula("DATEPART(minute, Datetime)"); Map(x => x.Seconds).Formula("DATEPART(second, Datetime)"); Map(x => x.WeekNo).Formula("DATEPART(week, Datetime)"); This is working all great .... but Week Datepart. I saw with NHProf the sql generating for a select and here's the problem it's generating all the sql correctly but for week datepart.. this is part of the SQL generated: ....Datepart(day, MyDate) ... ....Datepart(month, MyDate) ... ....Datepart(year, MyDate) ... ....Datepart(hour, MyDate) ... ....Datepart(minute, MyDate) ... ....Datepart(second, MyDate) ... ....Datepart(this_.week, MyDate) ... where this_ is the alias for the table that nhibernate uses. so it's treating the week keyword for the datepart stuff as a column or something like that. To clarify there's no column or properties that is called week. some help ? cheers Alessandro

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  • Context migration in CUDA.NET

    - by Vyacheslav
    I'm currently using CUDA.NET library by GASS. I need to initialize cuda arrays (actually cublas vectors, but it doesn't matters) in one CPU thread and use them in other CPU thread. But CUDA context which holding all initialized arrays and loaded functions, can be attached to only one CPU thread. There is mechanism called context migration API to detach context from one thread and attach it to another. But i don't how to properly use it in CUDA.NET. I tried something like this: class Program { private static float[] vector1, vector2; private static CUDA cuda; private static CUBLAS cublas; private static CUdeviceptr ptr; static void Main(string[] args) { cuda = new CUDA(false); cublas = new CUBLAS(cuda); cuda.Init(); cuda.CreateContext(0); AllocateVectors(); cuda.DetachContext(); CUcontext context = cuda.PopCurrentContext(); GetVectorFromDeviceAsync(context); } private static void AllocateVectors() { vector1 = new float[]{1f, 2f, 3f, 4f, 5f}; ptr = cublas.Allocate(vector1.Length, sizeof (float)); cublas.SetVector(vector1, ptr); vector2 = new float[5]; } private static void GetVectorFromDevice(object objContext) { CUcontext localContext = (CUcontext) objContext; cuda.PushCurrentContext(localContext); cuda.AttachContext(localContext); //change vector somehow vector1[0] = -1; //copy changed vector to device cublas.SetVector(vector1, ptr); cublas.GetVector(ptr, vector2); CUDADriver.cuCtxPopCurrent(ref localContext); } private static void GetVectorFromDeviceAsync(CUcontext cUcontext) { Thread thread = new Thread(GetVectorFromDevice); thread.IsBackground = false; thread.Start(cUcontext); } } But execution fails on attempt to copy changed vector to device because context is not attached? Any ideas how i can get it work?

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  • Exporting a non public Type through public API

    - by sachin
    I am trying to follow Trees tutorial at: http://cslibrary.stanford.edu/110/BinaryTrees.html Here is the code I have written so far: package trees.bst; import java.util.ArrayList; import java.util.List; import java.util.StringTokenizer; /** * * @author sachin */ public class BinarySearchTree { Node root = null; class Node { Node left = null; Node right = null; int data = 0; public Node(int data) { this.left = null; this.right = null; this.data = data; } } public void insert(int data) { root = insert(data, root); } public boolean lookup(int data) { return lookup(data, root); } public void buildTree(int numNodes) { for (int i = 0; i < numNodes; i++) { int num = (int) (Math.random() * 10); System.out.println("Inserting number:" + num); insert(num); } } public int size() { return size(root); } public int maxDepth() { return maxDepth(root); } public int minValue() { return minValue(root); } public int maxValue() { return maxValue(root); } public void printTree() { //inorder traversal System.out.println("inorder traversal:"); printTree(root); System.out.println("\n--------------"); } public void printPostorder() { //inorder traversal System.out.println("printPostorder traversal:"); printPostorder(root); System.out.println("\n--------------"); } public int buildTreeFromOutputString(String op) { root = null; int i = 0; StringTokenizer st = new StringTokenizer(op); while (st.hasMoreTokens()) { String stNum = st.nextToken(); int num = Integer.parseInt(stNum); System.out.println("buildTreeFromOutputString: Inserting number:" + num); insert(num); i++; } return i; } public boolean hasPathSum(int pathsum) { return hasPathSum(pathsum, root); } public void mirror() { mirror(root); } public void doubleTree() { doubleTree(root); } public boolean sameTree(BinarySearchTree bst) { //is this tree same as another given tree? return sameTree(this.root, bst.getRoot()); } public void printPaths() { if (root == null) { System.out.println("print path sum: tree is empty"); } List pathSoFar = new ArrayList(); printPaths(root, pathSoFar); } ///-------------------------------------------Public helper functions public Node getRoot() { return root; } //Exporting a non public Type through public API ///-------------------------------------------Helper Functions private boolean isLeaf(Node node) { if (node == null) { return false; } if (node.left == null && node.right == null) { return true; } return false; } ///----------------------------------------------------------- private boolean sameTree(Node n1, Node n2) { if ((n1 == null && n2 == null)) { return true; } else { if ((n1 == null || n2 == null)) { return false; } else { if ((n1.data == n2.data)) { return (sameTree(n1.left, n2.left) && sameTree(n1.right, n2.right)); } } } return false; } private void doubleTree(Node node) { //create a copy //bypass the copy to continue looping if (node == null) { return; } Node copyNode = new Node(node.data); Node temp = node.left; node.left = copyNode; copyNode.left = temp; doubleTree(copyNode.left); doubleTree(node.right); } private void mirror(Node node) { if (node == null) { return; } Node temp = node.left; node.left = node.right; node.right = temp; mirror(node.left); mirror(node.right); } private void printPaths(Node node, List pathSoFar) { if (node == null) { return; } pathSoFar.add(node.data); if (isLeaf(node)) { System.out.println("path in tree:" + pathSoFar); pathSoFar.remove(pathSoFar.lastIndexOf(node.data)); //only the current node, a node.data may be duplicated return; } else { printPaths(node.left, pathSoFar); printPaths(node.right, pathSoFar); } } private boolean hasPathSum(int pathsum, Node node) { if (node == null) { return false; } int val = pathsum - node.data; boolean ret = false; if (val == 0 && isLeaf(node)) { ret = true; } else if (val == 0 && !isLeaf(node)) { ret = false; } else if (val != 0 && isLeaf(node)) { ret = false; } else if (val != 0 && !isLeaf(node)) { //recurse further ret = hasPathSum(val, node.left) || hasPathSum(val, node.right); } return ret; } private void printPostorder(Node node) { //inorder traversal if (node == null) { return; } printPostorder(node.left); printPostorder(node.right); System.out.print(" " + node.data); } private void printTree(Node node) { //inorder traversal if (node == null) { return; } printTree(node.left); System.out.print(" " + node.data); printTree(node.right); } private int minValue(Node node) { if (node == null) { //error case: this is not supported return -1; } if (node.left == null) { return node.data; } else { return minValue(node.left); } } private int maxValue(Node node) { if (node == null) { //error case: this is not supported return -1; } if (node.right == null) { return node.data; } else { return maxValue(node.right); } } private int maxDepth(Node node) { if (node == null || (node.left == null && node.right == null)) { return 0; } int ldepth = 1 + maxDepth(node.left); int rdepth = 1 + maxDepth(node.right); if (ldepth > rdepth) { return ldepth; } else { return rdepth; } } private int size(Node node) { if (node == null) { return 0; } return 1 + size(node.left) + size(node.right); } private Node insert(int data, Node node) { if (node == null) { node = new Node(data); } else if (data <= node.data) { node.left = insert(data, node.left); } else { node.right = insert(data, node.right); } //control should never reach here; return node; } private boolean lookup(int data, Node node) { if (node == null) { return false; } if (node.data == data) { return true; } if (data < node.data) { return lookup(data, node.left); } else { return lookup(data, node.right); } } public static void main(String[] args) { BinarySearchTree bst = new BinarySearchTree(); int treesize = 5; bst.buildTree(treesize); //treesize = bst.buildTreeFromOutputString("4 4 4 6 7"); treesize = bst.buildTreeFromOutputString("3 4 6 3 6"); //treesize = bst.buildTreeFromOutputString("10"); for (int i = 0; i < treesize; i++) { System.out.println("Searching:" + i + " found:" + bst.lookup(i)); } System.out.println("tree size:" + bst.size()); System.out.println("maxDepth :" + bst.maxDepth()); System.out.println("minvalue :" + bst.minValue()); System.out.println("maxvalue :" + bst.maxValue()); bst.printTree(); bst.printPostorder(); int pathSum = 10; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); pathSum = 6; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); pathSum = 19; System.out.println("hasPathSum " + pathSum + ":" + bst.hasPathSum(pathSum)); bst.printPaths(); bst.printTree(); //bst.mirror(); System.out.println("Tree after mirror function:"); bst.printTree(); //bst.doubleTree(); System.out.println("Tree after double function:"); bst.printTree(); System.out.println("tree size:" + bst.size()); System.out.println("Same tree:" + bst.sameTree(bst)); BinarySearchTree bst2 = new BinarySearchTree(); bst2.buildTree(treesize); treesize = bst2.buildTreeFromOutputString("3 4 6 3 6"); bst2.printTree(); System.out.println("Same tree:" + bst.sameTree(bst2)); System.out.println("---"); } } Now the problem is that netbeans shows Warning: Exporting a non public Type through public API for function getRoot(). I write this function to get root of tree to be used in sameTree() function, to help comparison of "this" with given tree. Perhaps this is a OOP design issue... How should I restructure the above code that I do not get this warning and what is the concept I am missing here?

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  • Retrieve EF4 POCOs using WCF REST services starter kit

    - by muruge
    I am using WCF REST service (GET method) to retrieve my EF4 POCOs. The service seem to work just fine. When I query the uri in my browser I get the results as expected. In my client application I am trying to use WCF REST Starter Kit's HTTPExtension method - ReadAsDataContract() to convert the result back into my POCO. This works fine when the POCO's navigation property is a single object of related POCO. The problem is when the navigation property is a collection of related POCOs. The ReadAsDataContract() method throws an exception with message "Object reference not set to an instance of an object." Below are my POCOs. [DataContract(Namespace = "", Name = "Trip")] public class Trip { [DataMember(Order = 1)] public virtual int TripID { get; set; } [DataMember(Order = 2)] public virtual int RegionID { get; set; } [DataMember(Order = 3)] public virtual System.DateTime BookingDate { get; set; } [DataMember(Order = 4)] public virtual Region Region { // removed for brevity } } [DataContract(Namespace = "", Name = "Region")] public class Region { [DataMember(Order = 1)] public virtual int RegionID { get; set; } [DataMember(Order = 2)] public virtual string RegionCode { get; set; } [DataMember(Order = 3)] public virtual FixupCollection<Trip> Trips { // removed for brevity } } [CollectionDataContract(Namespace = "", Name = "{0}s", ItemName = "{0}")] [Serializable] public class FixupCollection<T> : ObservableCollection<T> { protected override void ClearItems() { new List<T>(this).ForEach(t => Remove(t)); } protected override void InsertItem(int index, T item) { if (!this.Contains(item)) { base.InsertItem(index, item); } } } And this is how I am trying retrieve a Region POCO. static void GetRegion() { string uri = "http://localhost:8080/TripService/Regions?id=1"; HttpClient client = new HttpClient(uri); using (HttpResponseMessage response = client.Get(uri)) { Region region; response.EnsureStatusIsSuccessful(); try { region = response.Content.ReadAsDataContract<Region>(); // this line throws exception because Region returns a collection of related trips Console.WriteLine(region.RegionName); } catch (Exception ex) { Console.WriteLine(ex.Message); } } } Would appreciate any pointers.

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  • How to use Castle Windsor with ASP.Net web forms?

    - by Xian
    I am trying to wire up dependency injection with Windsor to standard asp.net web forms. I think I have achieved this using a HttpModule and a CustomAttribute (code shown below), although the solution seems a little clunky and was wondering if there is a better supported solution out of the box with Windsor? There are several files all shown together here // index.aspx.cs public partial class IndexPage : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { Logger.Write("page loading"); } [Inject] public ILogger Logger { get; set; } } // WindsorHttpModule.cs public class WindsorHttpModule : IHttpModule { private HttpApplication _application; private IoCProvider _iocProvider; public void Init(HttpApplication context) { _application = context; _iocProvider = context as IoCProvider; if(_iocProvider == null) { throw new InvalidOperationException("Application must implement IoCProvider"); } _application.PreRequestHandlerExecute += InitiateWindsor; } private void InitiateWindsor(object sender, System.EventArgs e) { Page currentPage = _application.Context.CurrentHandler as Page; if(currentPage != null) { InjectPropertiesOn(currentPage); currentPage.InitComplete += delegate { InjectUserControls(currentPage); }; } } private void InjectUserControls(Control parent) { if(parent.Controls != null) { foreach (Control control in parent.Controls) { if(control is UserControl) { InjectPropertiesOn(control); } InjectUserControls(control); } } } private void InjectPropertiesOn(object currentPage) { PropertyInfo[] properties = currentPage.GetType().GetProperties(); foreach(PropertyInfo property in properties) { object[] attributes = property.GetCustomAttributes(typeof (InjectAttribute), false); if(attributes != null && attributes.Length > 0) { object valueToInject = _iocProvider.Container.Resolve(property.PropertyType); property.SetValue(currentPage, valueToInject, null); } } } } // Global.asax.cs public class Global : System.Web.HttpApplication, IoCProvider { private IWindsorContainer _container; public override void Init() { base.Init(); InitializeIoC(); } private void InitializeIoC() { _container = new WindsorContainer(); _container.AddComponent<ILogger, Logger>(); } public IWindsorContainer Container { get { return _container; } } } public interface IoCProvider { IWindsorContainer Container { get; } }

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  • Retrieve input entered in a JDialog

    - by Jules Olléon
    I extended JDialog to create a custom dialog where the user must fill some fields : How should I retrieve the data entered ? I came up with a solution that works. It mimics JOptionPane but the way I do it looks ugly to me because of the static fields involved... Here is roughly my code : public class FObjectDialog extends JDialog implements ActionListener { private static String name; private static String text; private JTextField fName; private JTextArea fText; private JButton bAdd; private JButton bCancel; private FObjectDialog(Frame parentFrame) { super(parentFrame,"Add an object",true); // build the whole dialog buildNewObjectDialog(); setVisible(true); } @Override public void actionPerformed(ActionEvent ae) { if(ae.getSource()==bAdd){ name=fName.getText(); text=fText.getText(); } else { name=null; text=null; } setVisible(false); dispose(); } public static String[] showCreateDialog(Frame parentFrame){ new FObjectDialog(parentFrame); String[] res={name,text}; if((name==null)||(text==null)) res=null; return res; } } As I said, that works properly, but I guess that might raise serious concurrency issues... Is there a cleaner way to do that ? How is it done in JOptionPane ?

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  • @OneToMany and composite primary keys?

    - by Kris Pruden
    Hi, I'm using Hibernate with annotations (in spring), and I have an object which has an ordered, many-to-one relationship which a child object which has a composite primary key, one component of which is a foreign key back to the id of the parent object. The structure looks something like this: +=============+ +================+ | ParentObj | | ObjectChild | +-------------+ 1 0..* +----------------+ | id (pk) |-----------------| parentId | | ... | | name | +=============+ | pos | | ... | +================+ I've tried a variety of combinations of annotations, none of which seem to work. This is the closest I've been able to come up with: @Entity public class ParentObject { @Column(nullable=false, updatable=false) private String id; @OneToMany(mappedBy="object", fetch=FetchType.EAGER) @IndexColumn(name = "pos", base=0) private List<ObjectChild> attrs; ... } @Entity public class ChildObject { @Embeddable public static class Pk implements Serializable { @Column(nullable=false, updatable=false) private String objectId; @Column(nullable=false, updatable=false) private String name; @Column(nullable=false, updatable=false) private int pos; ... } @EmbeddedId private Pk pk; @ManyToOne @JoinColumn(name="parentId") private ParentObject parent; ... } I arrived at this after a long bout of experimentation in which most of my other attempts yielded entities which hibernate couldn't even load for various reasons. The error I get when I try to read one of these objects (they seem to save OK), I get an error of this form: org.hibernate.exception.SQLGrammarException: could not initialize a collection: ... And the root cause is this: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column 'attrs0_.id' in 'field list' I'm sure I'm missing something simple, but the documentation is not clear on this matter, and I haven't been able to find any examples of this anywhere else. Thanks!

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  • How can I handle events within my custom control?

    - by highone
    I am not looking to create new events. I need to create a canvas control that optionally fades in or out depending on whether or not the mouse is over it. The code below probably explains what I want to do better than I can. private Storyboard fadeInStoryboard; private Storyboard fadeOutStoryboard; public FadingOptionPanel() { InitializeComponent(); } public static readonly DependencyProperty FadeEnabledProperty = DependencyProperty.Register("IsFadeEnabled", typeof(bool), typeof(FadingOptionPanel), new FrameworkPropertyMetadata(true, OnFadeEnabledPropertyChanged, OnCoerceFadeEnabledProperty)); public bool IsFadeEnabled { get { return (bool)GetValue(FadeEnabledProperty); } set { SetValue(FadeEnabledProperty, value); } } private static void OnFadeEnabledPropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e) { } private static object OnCoerceFadeEnabledProperty(DependencyObject sender, object data) { if (data.GetType() != typeof(bool)) { data = true; } return data; } private void FadingOptionPanel_MouseEnter(object sender, MouseEventArgs e) { if (IsFadeEnabled) { fadeInStoryboard.Begin(this); } } private void FadingOptionPanel_MouseLeave(object sender, MouseEventArgs e) { if (IsFadeEnabled) { fadeOutStoryboard.Begin(this); } } private void FadingOptionsPanel_Loaded(object sender, RoutedEventArgs e) { //Initialize Fade In Animation DoubleAnimation fadeInDoubleAnimation = new DoubleAnimation(); fadeInDoubleAnimation.From = 0; fadeInDoubleAnimation.To = 1; fadeInDoubleAnimation.Duration = new Duration(TimeSpan.FromSeconds(.5)); fadeInStoryboard = new Storyboard(); fadeInStoryboard.Children.Add(fadeInDoubleAnimation); Storyboard.SetTargetName(fadeInDoubleAnimation, this.Name); Storyboard.SetTargetProperty(fadeInDoubleAnimation, new PropertyPath(Canvas.OpacityProperty)); //Initialize Fade Out Animation DoubleAnimation fadeOutDoubleAnimation = new DoubleAnimation(); fadeOutDoubleAnimation.From = 1; fadeOutDoubleAnimation.To = 0; fadeOutDoubleAnimation.Duration = new Duration(TimeSpan.FromSeconds(.2)); fadeOutStoryboard = new Storyboard(); fadeOutStoryboard.Children.Add(fadeOutDoubleAnimation); Storyboard.SetTargetName(fadeOutDoubleAnimation, this.Name); Storyboard.SetTargetProperty(fadeOutDoubleAnimation, new PropertyPath(Canvas.OpacityProperty)); } I originally was using this code inside a usercontrol instead of a custom control before I found out that usercontrols don't support content.

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  • Hibernate one-to-one mapping

    - by Andrey Yaskulsky
    I have one-to-one hibernate mapping between class Student and class Points: @Entity @Table(name = "Users") public class Student implements IUser { @Id @Column(name = "id") private int id; @Column(name = "name") private String name; @Column(name = "password") private String password; @OneToOne(fetch = FetchType.EAGER, mappedBy = "student") private Points points; @Column(name = "type") private int type = getType(); //gets and sets... @Entity @Table(name = "Points") public class Points { @GenericGenerator(name = "generator", strategy = "foreign", parameters = @Parameter(name = "property", value = "student")) @Id @GeneratedValue(generator = "generator") @Column(name = "id", unique = true, nullable = false) private int Id; @OneToOne @PrimaryKeyJoinColumn private Student student; //gets and sets And then i do: Student student = new Student(); student.setId(1); student.setName("Andrew"); student.setPassword("Password"); Points points = new Points(); points.setPoints(0.99); student.setPoints(points); points.setStudent(student); Session session = HibernateUtil.getSessionFactory().getCurrentSession(); session.beginTransaction(); session.save(student); session.getTransaction().commit(); And hibernate saves student in the table but not saves corresponding points. Is it OK? Should i save points separately?

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  • Mapping Hashmap of Coordinates in Hibernate with Annotation

    - by paddydub
    I've just started using hibernate and I'm trying to map walking distance between two coordinates into a hashmap, There can be many connections from one "FromCoordinate" to another "ToCoordinate". I'm not sure if i've implemented this correctly, What annotations do i need to map this MashMap? Thanks HashMap coordWalkingConnections = new HashMap(); @Entity @Table(name = "COORDCONNECTIONS") public class CoordinateConnection implements Serializable{ private static final long serialVersionUID = -1624745319005591573L; /** auto increasing id number */ @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "ID") @id private int id; @Embedded public FromCoordinate fromCoord; @Embedded public ToCoordinate toCoord; HashMap<FromCoordinate, ArrayList<ToCoordinate >> coordWalkingConnections = new HashMap<FromCoordinate, ArrayList<ToCoordinate >>(); } public class FromCoordinate implements ICoordinate { @Column(name = "FROM_LAT") private double latitude; @Column(name = "FROM_LNG") private double longitude; } public class ToCoordinate implements ICoordinate { @Column(name = "TO_LAT") private double latitude; @Column(name = "TO_LNG") private double longitude; @Column(name = "DISTANCE") private double distance; } DATABASE STRUCTURE id FROM_LAT FROM_LNG TO_LAT TO_LNG Dist 1 43.352669 -6.264341 43.350012 -6.260653 0.38 2 43.352669 -6.264341 43.352669 -6.264341 0.00 3 46.352669 -6.264341 43.353373 -6.262013 0.17 4 47.352465 -6.265865 43.351290 -6.261200 0.25 5 45.452578 -6.265768 43.352788 -6.264396 0.01 6 45.452578 -6.265768 45.782788 -6.234523 0.01 ..... ... . Example HashMap for HashMap<Coordinate, ArrayList<Coordinate>> <KEY{43.352669 -6.264341}, Arraylist VALUES{(43.350012,-6.260653,0.383657), (43.352669, -6.264341, 0.000095), (43.353373, -6.262013, 0.173201)}> <KEY{47.352465 -6.265865}, Arraylist VALUES{(43.351290,-6.261200,0.258781)}> <KEY{45.452578 -6.265768}, Arraylist VALUES{(43.352788,-6.264396,0.013726),(45.782788,-6.234523,0.017726)}>

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  • VB.NET handling data between different forms

    - by niuchu
    Hi, I'm writing a simple application - address book. User enters new addresses and they are added as an entry to a list visible on the main form (frmStart). I use one form to add and edit (AddContForm). Add button on the frmStart works fine, however I experience some problems with the edit button as when I press it and enter new data they are added as new entry however the previous entry is still there. Logic is handled by Contact.vb class. Please let me know how to fix this problem. Here is the code: Contact.vb Public Class Contact Public Contact As String Public Title As String Public Fname As String Public Surname As String Public Address As String Private myCont As String Public Property Cont() Get Return myCont End Get Set(ByVal value) myCont = Value End Set End Property Public Overrides Function ToString() As String Return Me.Cont End Function Public Sub Display() Dim C As New Contact C.Cont = frmAddCont.txtTitle.Text C.Fname = frmAddCont.txtFName.Text C.Surname = frmAddCont.txtSName.Text C.Address = frmAddCont.txtAddress.Text frmStart.lstContact.Items.Add(C) End Sub End Class Here is frmStart.vb Public Class frmStart Public Button As String Private Sub btnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAdd.Click Button = "" Button = "Add" frmAddCont.ShowDialog() End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDel.Click Button = "" Button = "Del" Dim DelCont As Contact DelCont = Me.lstContact.SelectedItem() lstContact.Items.Remove(DelCont) End Sub Private Sub lstContact_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstContact.SelectedIndexChanged End Sub Private Sub btnEdit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEdit.Click Button = "" Button = "Edit" Dim C As Contact If lstContact.SelectedItem IsNot Nothing Then C = DirectCast(lstContact.SelectedItem, Contact) frmAddCont.ShowDialog() End If End Sub End Class Here is AddContFrm.vb Public Class frmAddCont Public Class ControlObject Dim Title As String Dim FName As String Dim SName As String Dim Address As String Dim TelephoneNumber As Integer Dim emailAddress As String Dim Website As String Dim Photograph As String End Class Private Sub btnConfirmAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConfirmAdd.Click Dim B As String B = frmStart.Button Dim C As New Contact C.Display() Me.Hide() If B = "Edit" Then C = DirectCast(frmStart.lstContact.SelectedItem, Contact) frmStart.lstContact.SelectedItems.Remove(C) End If End Sub Private Sub frmAddCont_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub End Class

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  • 'SImple' 2 class Java calculator doesn't accept inputs or do calculations

    - by Tony O'Keeffe
    Hi, I'm trying to get a two class java calculator working (new to java) to work but so far i'm having no success. the two classes are outlined below, calcFrame is for the interface and calEngine should do the actual calculations but i can't get them to talk to one another. i'd really appreciate any assistance on same. Thanks. CalcFrame Code - import java.awt.; import javax.swing.; import javax.swing.border.; import java.awt.event.; /** *A Class that operates as the framework for a calculator. *No calculations are performed in this section */ public class CalcFrame implements ActionListener { private CalcEngine calc; private JFrame frame; private JTextField display; private JLabel status; /** * Constructor for objects of class GridLayoutExample */ public CalcFrame() { makeFrame(); //calc = engine; } /** * This allows you to quit the calculator. */ // Alows the class to quit. private void quit() { System.exit(0); } // Calls the dialog frame with the information about the project. private void showAbout() { JOptionPane.showMessageDialog(frame, "Group Project", "About Calculator Group Project", JOptionPane.INFORMATION_MESSAGE); } private void makeFrame() { frame = new JFrame("Group Project Calculator"); makeMenuBar(frame); JPanel contentPane = (JPanel)frame.getContentPane(); contentPane.setLayout(new BorderLayout(8, 8)); contentPane.setBorder(new EmptyBorder( 10, 10, 10, 10)); /** * Insert a text field */ display = new JTextField(); contentPane.add(display, BorderLayout.NORTH); //Container contentPane = frame.getContentPane(); contentPane.setLayout(new GridLayout(4, 4)); JPanel buttonPanel = new JPanel(new GridLayout(4, 4)); contentPane.add(new JButton("1")); contentPane.add(new JButton("2")); contentPane.add(new JButton("3")); contentPane.add(new JButton("4")); contentPane.add(new JButton("5")); contentPane.add(new JButton("6")); contentPane.add(new JButton("7")); contentPane.add(new JButton("8")); contentPane.add(new JButton("9")); contentPane.add(new JButton("0")); contentPane.add(new JButton("+")); contentPane.add(new JButton("-")); contentPane.add(new JButton("/")); contentPane.add(new JButton("*")); contentPane.add(new JButton("=")); contentPane.add(new JButton("C")); contentPane.add(buttonPanel, BorderLayout.CENTER); //status = new JLabel(calc.getAuthor()); //contentPane.add(status, BorderLayout.SOUTH); frame.pack(); frame.setVisible(true); } /** * Create the main frame's menu bar. * The frame that the menu bar should be added to. */ private void makeMenuBar(JFrame frame) { final int SHORTCUT_MASK = Toolkit.getDefaultToolkit().getMenuShortcutKeyMask(); JMenuBar menubar = new JMenuBar(); frame.setJMenuBar(menubar); JMenu menu; JMenuItem item; // create the File menu menu = new JMenu("File"); menubar.add(menu); // create the Quit menu with a shortcut "Q" key. item = new JMenuItem("Quit"); item.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q, SHORTCUT_MASK)); item.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { quit(); } }); menu.add(item); // Adds an about menu. menu = new JMenu("About"); menubar.add(menu); // Displays item = new JMenuItem("Calculator Project"); item.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { showAbout(); } }); menu.add(item); } /** * An interface action has been performed. * Find out what it was and handle it. * @param event The event that has occured. */ public void actionPerformed(ActionEvent event) { String command = event.getActionCommand(); if(command.equals("0") || command.equals("1") || command.equals("2") || command.equals("3") || command.equals("4") || command.equals("5") || command.equals("6") || command.equals("7") || command.equals("8") || command.equals("9")) { int number = Integer.parseInt(command); calc.numberPressed(number); } else if(command.equals("+")) { calc.plus(); } else if(command.equals("-")) { calc.minus(); } else if(command.equals("=")) { calc.equals(); } else if(command.equals("C")) { calc.clear(); } else if(command.equals("?")) { } // else unknown command. redisplay(); } /** * Update the interface display to show the current value of the * calculator. */ private void redisplay() { display.setText("" + calc.getDisplayValue()); } /** * Toggle the info display in the calculator's status area between the * author and version information. */ } CalcEngine - public class CalcEngine { // The calculator's state is maintained in three fields: // buildingDisplayValue, haveLeftOperand, and lastOperator. // The current value (to be) shown in the display. private int displayValue; // The value of an existing left operand. private int leftOperand; /** * Create a CalcEngine. */ public CalcEngine() { clear(); } public int getDisplayValue() { return displayValue; } /** * A number button was pressed. * Either start a new operand, or incorporate this number as * the least significant digit of an existing one. * @param number The number pressed on the calculator. */ public void numberPressed(int number) { if(buildingDisplayValue) { // Incorporate this digit. displayValue = displayValue*10 + number; } else { // Start building a new number. displayValue = number; buildingDisplayValue = true; } } /** * The 'plus' button was pressed. */ public void plus() { applyOperator('+'); } /** * The 'minus' button was pressed. */ public void minus() { applyOperator('-'); } /** * The '=' button was pressed. */ public void equals() { // This should completes the building of a second operand, // so ensure that we really have a left operand, an operator // and a right operand. if(haveLeftOperand && lastOperator != '?' && buildingDisplayValue) { calculateResult(); lastOperator = '?'; buildingDisplayValue = false; } else { keySequenceError(); } } /** * The 'C' (clear) button was pressed. * Reset everything to a starting state. */ public void clear() { lastOperator = '?'; haveLeftOperand = false; buildingDisplayValue = false; displayValue = 0; } /** * @return The title of this calculation engine. */ public String getTitle() { return "Java Calculator"; } /** * @return The author of this engine. */ public String getAuthor() { return "David J. Barnes and Michael Kolling"; } /** * @return The version number of this engine. */ public String getVersion() { return "Version 1.0"; } /** * Combine leftOperand, lastOperator, and the * current display value. * The result becomes both the leftOperand and * the new display value. */ private void calculateResult() { switch(lastOperator) { case '+': displayValue = leftOperand + displayValue; haveLeftOperand = true; leftOperand = displayValue; break; case '-': displayValue = leftOperand - displayValue; haveLeftOperand = true; leftOperand = displayValue; break; default: keySequenceError(); break; } } /** * Apply an operator. * @param operator The operator to apply. */ private void applyOperator(char operator) { // If we are not in the process of building a new operand // then it is an error, unless we have just calculated a // result using '='. if(!buildingDisplayValue && !(haveLeftOperand && lastOperator == '?')) { keySequenceError(); return; } if(lastOperator != '?') { // First apply the previous operator. calculateResult(); } else { // The displayValue now becomes the left operand of this // new operator. haveLeftOperand = true; leftOperand = displayValue; } lastOperator = operator; buildingDisplayValue = false; } /** * Report an error in the sequence of keys that was pressed. */ private void keySequenceError() { System.out.println("A key sequence error has occurred."); // Reset everything. clear(); } }

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