Rose Jac

Thank you very much! That worked.

Hello,

I am trying to implement this method, but the where clause in the sql seems to be not working. My database has the fields : ID, lastName, firstName, mi, address, city, state, telephone, email with 2 records.
The code attempts to display a specific record whose id is entered by the user in a JApplet's Textfield and then, the other fields of the reocrd corresponding to that id is displayed on the other textfields on clicking the 'View' JButton.
Do help.

jbtView.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { int id = Integer.parseInt(jtID.getText().toString()); System.out.println("ID chosen: " + id); try { ResultSet rs1 = st.executeQuery("SELECT * FROM Staff"); //This and the following 2 lines of code are working perfecftly. while(rs1.next()) System.out.println(rs1.getString(7)); String query = "SELECT lastName, firstName, mi, address, city, state, telephone, email FROM Staff WHERE ID = '" + id + "'"; //This is not working. Any problem in the where clause?? ResultSet rs = st.executeQuery(query); if(rs.next()) { String lastName = rs.getString(2); String firstName = rs.getString(3); String mi = rs.getString(4); String address = rs.getString(5); String city = rs.getString(6); String state = rs.getString(7); String ph = rs.getString(8); String email = rs.getString(9); jtLName.setText(lastName); jtFName.setText(firstName); jtmi.setText(mi); jtAddress.setText(address); jtCity.setText(city); jtState.setText(state); jtPh.setText(ph); jtEmail.setText(email); } } catch(SQLException ex) {} } });

Thanks!

Repainting of panels...actually, several circles and few images that are redrawn using timer, so as to create "motion".

well. A whole task is perofrmed, like repainting of panels, continuously for 100seconds and the graph is plotted evyr 5th second. So i cant do that.

Hi.

I have made a swing application. It uses timer FOR performing certain tasks and it uses the following code get the current second:
SimpleDateFormat formatter = new SimpleDateFormat("ss"); String format = formatter.format(new Date());

Now, if the current second is completely divisible by 5, then a graph is updated.ie. graph gets updated every 5th second The graph should begin at time, t = 0; So, what i have done is initialised a variable 'time' to 0. When the second got from above code is divisible by 5, then graph is updated and time is incremented by 5.
Now, the graph is updated for the whole of the 5th second. Now, the problem i face is that the variable time is getting incemented by 5 twice in the 5th second...so, i am multiple values of x-axis (which corresponds to time) as the variable 'time' represents the x-axis, and hece, a wrong result.
I want the variable time to retain the same value for the whole of 5th second and get incremented by 5 in th enext 5th second.
Any idea?
Thanks!

Ok. I figured it out. I forgot to add D's directadjacentnodes.
Thanks!

Dijkstra algorithm:
What changes should i make?

public final class Dijkstra { HashMap<Integer, String> verticesMap = new HashMap(); HashMap<String, HashMap<String, Integer>> adjacencyMap = new HashMap(); Dijkstra(ArrayList<Node> nodeList) { for(Node n : nodeList) { verticesMap.put(n.id, n.name); } for(Node n : nodeList) { HashMap<String, Integer> hm = new HashMap(); for(Node n1 : n.directAdjacencyList) { hm.put(verticesMap.get(n1.id), 1); adjacencyMap.put(n.name, hm); } } System.out.println(" vertices map " + verticesMap); System.out.println(" adjacencyMap " + adjacencyMap); System.out.println(verticesMap.get(5)); System.out.println(verticesMap.get(1)); doDijkstra(verticesMap.get(1), verticesMap.get(5)); } public Map<String, Integer> getAdjacentVertices(String vertexName){ return adjacencyMap.get(vertexName); } public int getAdjacentCost(String startVertexName, String endVertexName){ return adjacencyMap.get(startVertexName).get(endVertexName); } public int doDijkstra(String vertexStartName, String vertexEndName) { ArrayList<String> pathList = new ArrayList(); HashMap<String, Integer> costPerNode = new HashMap<String, Integer>(); ArrayList<String> processed = new ArrayList<String>(); ArrayList<String> inQueue = new ArrayList<String>(); costPerNode.put(vertexStartName, 0); Iterator<String> iterator = getAdjacentVertices(vertexStartName).keySet().iterator(); while(iterator.hasNext()) { String next = iterator.next(); costPerNode.put(next, getAdjacentCost(vertexStartName, next)); inQueue.add(next); } System.out.println( " Q " + inQueue); processed.add(vertexStartName); System.out.println(" processed " + processed); while(!inQueue.isEmpty()) { iterator = getAdjacentVertices(inQueue.get(0)).keySet().iterator(); ///null pointer while(iterator.hasNext()) { String next = iterator.next(); if(!processed.contains(next)) inQueue.add(next); if(costPerNode.get(next) == null) { int cost = costPerNode.get(inQueue.get(0)) + getAdjacentCost(inQueue.get(0), next); costPerNode.put(next, cost); } else if(costPerNode.get(inQueue.get(0)) + getAdjacentCost(inQueue.get(0), next) < costPerNode.get(next)) { costPerNode.put(next, costPerNode.get(inQueue.get(0)) + getAdjacentCost(inQueue.get(0), next)); inQueue.add(next); } } processed.add(inQueue.get(0)); inQueue.remove(0); } processed.clear(); inQueue.clear(); if(costPerNode.get(vertexEndName) != null) return costPerNode.get(vertexEndName); else return 0; } public static void main(String args[]) { Node a = new Node(1, "A"); Node b = new Node(2, "B"); Node c = new Node(3, "C"); Node d = new Node(4, "D"); Node e = new Node(5, "E"); ArrayList<Node> nodeList = new ArrayList(); nodeList.add(a); nodeList.add(b); nodeList.add(c); nodeList.add(d); nodeList.add(e); for(Node n : nodeList) n.directAdjacencyList = new ArrayList(); a.directAdjacencyList.add(b); a.directAdjacencyList.add(c); b.directAdjacencyList.add(a); b.directAdjacencyList.add(d); c.directAdjacencyList.add(a); c.directAdjacencyList.add(d); e.directAdjacencyList.add(d); Dijkstra da = new Dijkstra(nodeList); //null pointer } }

output:
run:
vertices map {1=A, 2=B, 3=C, 4=D, 5=E}
Exception in thread "main" java.lang.NullPointerException
adjacencyMap {E={D=1}, A={B=1, C=1}, B={D=1, A=1}, C={D=1, A=1}}
E
A
Q [B, C]
processed [A]
at simulation.Dijkstra.doDijkstra(Dijkstra.java:73)
at simulation.Dijkstra.<init>(Dijkstra.java:43)
at simulation.Dijkstra.main(Dijkstra.java:155)
Java Result: 1
BUILD SUCCESSFUL (total time: 2 seconds)


help please!

I am running a swing application. And i am getting this error several times, even after changing the code. I am using a java.util.timer, to display moving circles in a panel and do certain functions depending on its position.
The timer starts and everything goes perfectly fine for about 5-10minutes and then, this error is shown:
How may I fix this?

Exception in thread "Timer-0" java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at simulation.SceneDetails.setManetListForDesert(SceneDetails.java:325)
at simulation.nodePanel$1.run(SimualtionFrame.java:227)
at java.util.TimerThread.mainLoop(Timer.java:512)
at java.util.TimerThread.run(Timer.java:462)

Thanks.

So sorry again. I have used timer here, though i dont think the circle is stopping at all!
And the circle is just too fast.

import java.applet.*; import java.awt.*; import java.awt.event.ActionListener; import java.util.Calendar; import java.util.Timer; import java.util.TimerTask; import javax.swing.*; class Ball { int width , height; int x = 0, y = 0, dx = 0, dy = 0, r = 0; Color color; Graphics g; public Ball() {} public Ball( int x, int y, int xinc, int yinc, int r, Rectangle b) { this.x=x; this.y=y; dx =xinc; dy=yinc; this.r = r; width = b.width; height = b.height; } public void move() { if ((x - r + dx < 0) || (x + r + dx > width)) dx = -dx; if ((y - r + dy < 0) || (y + r + dy > height)) dy = -dy; // Move the circle. x += dx; y += dy; } public void draw(Graphics gr) { g=gr; g.setColor(Color.red); g.drawOval((int)x,(int)y,(int)(2*r),(int)(2*r)); System.out.println(" X IS " + x); } } public class matt extends JPanel { Rectangle bounds; Ball b; public matt() throws InterruptedException { JFrame frame=new JFrame("At t = 0"); frame.add(this); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(900, 640); bounds = frame.getBounds(); this.setBackground(Color.white); frame.setLocationRelativeTo(null); frame.setVisible(true); b = new Ball(150, 50, -1, 1, 50, bounds); final Timer timer= new java.util.Timer(); TimerTask task= new TimerTask() { public void run() { while(true) { b.move(); repaint(); } } }; timer.schedule( task , 0, 5*1000); } public void paintComponent(Graphics g) { super.paintComponent(g); b.draw(g); } public static void main(String args[]) throws InterruptedException { matt ma = new matt(); } }
Thanks.
And do tell how to open this window with the press of a button in another class.

And i want to display this window when an "OK" button is pressed in another class, which i am not able to do.
Do help.

Thanks

Hi,

I am sorry for the trouble but i did read about timers. The thing is I do not have an ActionPerformed in my program.
The nth program i am trying (given below) does work fine but it is not the smooth motion i wanted to generate.

If there is a way to generate smooth motion using timers in this program, do mention.
And do note, i want the ball displayed in the frame to move every 20seconds and then stop for few seconds, say, 4 seconds. This continues till the window is closed.
/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package sample; import java.applet.*; import java.awt.*; import java.util.Calendar; import javax.swing.Timer; import javax.swing.*; class Ball { int width , height; double x, y, xinc, yinc, r; Color color; Graphics g; public int xr = 0, yr = 0; public Ball() {} public Ball( int x, int y, double xinc, double yinc, int r, Rectangle b) { this.x=x; this.y=y; this.xinc=xinc; this.yinc=yinc; this.r = r; width = b.width; height = b.height; } public void move() { x+=xinc; y+=yinc; //when the ball bumps against a boundary, it bounces off if(x<0 || x>width-2*r) { xinc=-xinc; x+=xinc; } if(y<0 || y>height-2*r) { yinc=-yinc; y+=yinc; } } public void draw(Graphics gr) { g=gr; g.setColor(Color.red); g.drawOval((int)x,(int)y,(int)(2*r),(int)(2*r)); System.out.println("\n X is " + x + " PPP " + y); xr = (int) x; yr = (int) y; } } public class algo1 extends JPanel { Rectangle bounds; Ball b; public algo1() throws InterruptedException { JFrame frame=new JFrame("At t = 0"); frame.add(this); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(900, 640); bounds = frame.getBounds(); this.setBackground(Color.white); frame.setLocationRelativeTo(null); frame.setVisible(true); b = new Ball(100, 200, 41, 41, 50, bounds); while(true) { Calendar calendar = Calendar.getInstance(); long time = calendar.get(Calendar.SECOND); if(time % 20 != 0) { b.move(); repaint(); } else { Thread.sleep(4000); } System.out.println("time is " + time); } } public void paintComponent(Graphics g) { super.paintComponent(g); b.draw(g); } public static void main(String args[]) throws InterruptedException { algo1 a = new algo1(); } }

The applet:
package manet; import java.awt.*; import java.applet.*; import java.util.*; class Ball { int width , height; double x, y, xinc, yinc, r; Color color; Graphics g; // public Ball() {} public Ball( int x, int y, double xinc, double yinc, int r, Rectangle b) { this.x=x; this.y=y; this.xinc=xinc; this.yinc=yinc; this.r = r; width = b.width; height = b.height; } public void move() { x+=xinc; y+=yinc; //when the ball bumps against a boundary, it bounces off if(x<0 || x>width-2*r) { xinc=-xinc; x+=xinc; } if(y<0 || y>height-2*r) { yinc=-yinc; y+=yinc; } } public void paint(Graphics gr) { g=gr; g.setColor(Color.red); g.drawOval((int)x,(int)y,(int)(2*r),(int)(2*r)); System.out.println("\n X is " + x + " PPP " + y); } } public class Motion extends Applet implements Runnable { Thread runner; Image Buffer; Graphics gBuffer; Ball ball[]; ArrayList<Ball> ball1 = new ArrayList(); Rectangle bounds; static final int MAX=5; public void set(int x[], int y[], int r[]) { for(int i = 0; i<x.length; i++) { ball1.add(new Ball(x[i], y[i], 3, 5, r[i], bounds)); } } public void init() { setSize(1000, 600); bounds = getBounds(); // bounds.width = 1000; // bounds.height = 700; // Ball a = new Ball(); // a.set(bounds); System.out.println(" bith " + bounds.width); Buffer=createImage(bounds.width, bounds.height); gBuffer=Buffer.getGraphics(); ball=new Ball[MAX]; int w=700; int h=700; // ball[0]=new Ball(50,20,1.5,3.0,50, bounds); // ball[1]=new Ball(60,100,2.0,4,100, bounds); // ball[2]=new Ball(15,70,13.0,5,20, bounds); // ball[3]=new Ball(150,60, 24.7,7.0,70, bounds); // ball[4]=new Ball(210,30,5.2,6.5,100, bounds); // ball1.add(ball[0]); // ball1.add(ball[1]); // ball1.add(ball[2]); // ball1.add(ball[3]); // ball1.add(ball[4]); int a = 30, b = 40, c = 2, d = 5, e = 10, i = 0; while(i<5) { ball1.add(new Ball(a, b, c, d, e, bounds)); a = a+10; b = b+10; c = c+10; d = d+10; e = e+10; i++; } } public void start() { if (runner == null) { runner = new Thread (this); runner.start(); } } public void stop() { if (runner != null) { runner.stop(); runner = null; } } public void run() { while(true) { Calendar calendar = Calendar.getInstance(); long i = calendar.get(Calendar.SECOND); if( i % 10 != 0) { System.out.println(i); try {runner.sleep(15);} catch (Exception e) { } for(Ball e : ball1) e.move(); repaint(); } else { try { Thread t = Thread.currentThread(); t.sleep(1000); t.resume(); } catch (InterruptedException ex) {} } } } public void update(Graphics g) { paint(g); } public void paint(Graphics g) { gBuffer.setColor(Color.white); gBuffer.fillRect(0,0,bounds.width,bounds.height); for(Ball e: ball1) { e.paint(gBuffer); } // // for(int i=0;i<MAX;i++) // ball[i].paint(gBuffer); g.drawImage (Buffer,0,0, this); } }

The other class:
/* * To change this template, choose Tools | Templates * and open the template in the editor. */ package manet; public class matt { public static void main(String args[]) { int x[] = new int[] { 100, 200, 300, 400}; int y[] = new int[] { 200, 100, 300, 450}; int r[] = new int[] { 30, 50, 100, 120}; Motion mo = new Motion(); mo.set(x, y, r); mo.init(); } }


Ouptut:
Exception in thread "main" java.lang.NullPointerException
at manet.Ball.<init>(Motion.java:21)
at manet.Motion.set(Motion.java:67)
at manet.matt.main(matt.java:20)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

Do help.
Thanks

Hi,

I have an applet in class 'A'.
I have another class = B.
Now, I have created a set(...) method in A and this set method will be called by B after instantiating A and all the parameters required to build the applet wll be set.
And after that, i have called the init() method of A using the same A's object.

This is not working. A nullPointerException is present. I am not able to call the applet after setting the parameters of the applet.
Am i doing it the wrong way?

Thanks!

Hi,

I want to bounce multiple circles off the Boundaries of an applet.
Till now, I have been able to do only one bouncing circle, whose x and y coordinate are explicitly specified in the program.
I want to add the circles from an arrayList.
Do i have to have multiple threads for such a program ie one thread for one circle?

Any help or tutorial on the same?

Thanks!

Can somebody check this code of mine?
I meant to draw four moving circles and somthing different came up, though the four circles can be seen.


import java.applet.Applet; import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import java.awt.Rectangle; import java.util.Calendar; import java.util.logging.Level; import java.util.logging.Logger; class Node { int x, y , r, xinc = 10, yinc = 10, width = 700, height = 700; Node(int x1, int y1, int r1) { x = x1; y = y1; r = r1; } public void move() { x+=xinc; y+=yinc; if(x<0 || x>1000-2*r) { xinc=-xinc; x+=xinc; } if(y<0 || y>700-2*r) { yinc=-yinc; y+=yinc; } } public void paint(Graphics g) { g.setColor(Color.red); g.drawOval(x,y,2*r,2*r); } } public class Motion extends Applet implements Runnable { public Rectangle bounds = getBounds(); int xa[] = new int[] { 400, 300, 200, 100}; int ya[] = new int[] { 100, 200, 300, 400}; int ra[] = new int[] { 50, 70, 90, 120 }; Thread runner; Image Buffer; Graphics gBuffer; Node nodes[]; public void init() { Buffer=createImage(size().width,size().height); gBuffer=Buffer.getGraphics(); int size = xa.length; nodes = new Node[size]; for(int i = 0 ; i<size; i++) { nodes[i] = new Node(xa[i], ya[i], ra[i]); } } public void start() { if (runner == null) { runner = new Thread (this); runner.start(); } } public void stop() { if (runner != null) { runner.stop(); runner = null; } } public void run() { while(true) { try {runner.sleep(15);} catch (Exception e) { } for(int i=0;i<xa.length;i++) nodes[i].move(); repaint(); } } public void update(Graphics g) { paint(g); } public void paint(Graphics g) { for(int i=0;i<xa.length;i++) nodes[i].paint(g); } }