Do not use on any
shared computer
August 30, 2008 03:32am pdt
 
[x]
Attachment Details

Exception in thread "main" java.lang.NullPointerException   again

Zones: Java Programming Language, Programming Languages
Hello Experts,

I need your assistance about this errors:
Exception in thread "main" java.lang.NullPointerException
      at ServerConnection.sendCommand(ServerConnection.java:41)
      at ServerConnection.look(ServerConnection.java:28)
      at Client.<init>(Client.java:76)
      at Client.main(Client.java:153)


Thanks in advance for any corrections !
1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91:
92:
93:
94:
95:
96:
97:
98:
99:
100:
101:
102:
103:
104:
105:
106:
107:
108:
109:
110:
111:
112:
113:
114:
115:
116:
117:
118:
119:
120:
121:
122:
123:
124:
125:
126:
127:
128:
129:
130:
131:
132:
133:
134:
135:
136:
137:
138:
139:
140:
141:
142:
143:
144:
145:
146:
147:
148:
149:
150:
151:
152:
153:
154:
155:
156:
157:
158:
159:
160:
161:
162:
163:
164:
165:
166:
167:
168:
169:
170:
171:
172:
173:
174:
175:
176:
177:
178:
179:
180:
181:
182:
183:
184:
185:
186:
187:
188:
189:
190:
191:
192:
193:
194:
195:
196:
197:
198:
199:
200:
201:
202:
203:
204:
205:
206:
207:
208:
209:
210:
211:
212:
213:
214:
215:
216:
217:
218:
219:
220:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;
 
public class ServerConnection
{
 
	public PrintWriter outToServer;
 
	public BufferedReader inFromServer ;
 
	private Socket clientSocket;
 
 
	public void connect(String host, int port) throws IOException
	{
		clientSocket = new Socket(host, port);
		inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
		outToServer = new PrintWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
 
	}
 
	public char[][] look() throws IOException	{
		sendCommand("LOOK");
		char[][] lookResponse = new char[5][];
		for (int i=0; i<5; i++) {
			String line =  inFromServer.readLine();
			System.out.println(line);
			lookResponse[i] = line.toCharArray();
 
		}
		return lookResponse;
	}
 
	private void sendCommand(String string) {
		System.out.println("Sending "+string);
		outToServer.println(string);
 
	}
 
}
 
 
 
 
 
 
 
 
public class Client extends JFrame  {
 
	private static final long serialVersionUID = -3054541431624115776L;
 
	private Socket clientSocket;
 
	static MyBoard myBoard;
 
	public Container contentPane;
 
	ServerConnection newConn = new ServerConnection();
 
	public Client() throws UnknownHostException, IOException {
		setTitle("Labyrinth");
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		setVisible(true);      
 
		String hostname = "localhost";
		int portNumber = 4455;
 
		clientSocket = new Socket(hostname, portNumber);
 
		setSize(900,800); 
 
		myBoard = new MyBoard("Images/Blank.jpg",10,10,10,10, 60,60);
 
		myBoard.setNoOfTiles(10000); // Total number of tiles
 
		contentPane = getContentPane();
		contentPane.setLayout(new BorderLayout());
 
 
		JScrollPane jsp = new JScrollPane(myBoard);
		contentPane.add("Center", jsp);
 
		//Buttons
		JButton goUpButton = new JButton("Up");
		JButton goDownButton = new JButton("Down");
		JButton goLeftButton = new JButton("Left");
		JButton goRightButton = new JButton("Right");
 
		//ActionListener for buttons
		goUpButton.addActionListener(myBoard);
		goDownButton.addActionListener(myBoard);
		goLeftButton.addActionListener(myBoard);
		goRightButton.addActionListener(myBoard);
 
		contentPane.add("West",goLeftButton);
		contentPane.add("East",goRightButton);
		contentPane.add("North",goUpButton);
		contentPane.add("South", goDownButton);
 
		setVisible(true);
 
 
		char[][] lookResponse = newConn.look();
 
		int mapHeight = lookResponse.length;
 
		int idmap = 1;
 
		for(int a=0;a<mapHeight;a++)
		{
			for(int b=0;b<lookResponse[a].length;b++)
			{
				switch(lookResponse[a][b])
				{
					case  'X': myBoard.setTile(++idmap,b,a,"Images/questionmark.jpg")  ; break;
					case  '#': myBoard.setTile(++idmap,b,a,"Images/wall.jpg")  ; break;
					case  '.': myBoard.setTile(++idmap,b,a,"Images/floor.jpg")  ; break;
					case  'E': myBoard.setTile(++idmap,b,a,"Images/exit.jpg")  ; break;
					case  'G': myBoard.setTile(++idmap,b,a,"Images/gold.jpg")  ; break;
					case  'H': myBoard.setTile(++idmap,b,a,"Images/health.jpg"); break;
					case  'S': myBoard.setTile(++idmap,b,a,"Images/sword.jpg") ; break;
					case  'A': myBoard.setTile(++idmap,b,a,"Images/armour.jpg"); break;
					case  'L': myBoard.setTile(++idmap,b,a,"Images/lantern.jpg"); break;
					case  'P': myBoard.setTile(++idmap,b,a,"Images/player.jpg") ; break;
				}
				repaint();
			}
			repaint();
		}
		repaint();
 
		JMenuBar menuBar = new JMenuBar();
		setJMenuBar(menuBar);
 
		JMenu fileMenu = new JMenu("File");
		JMenu sendCommand = new JMenu("Command");
 
		menuBar.add(fileMenu);
		menuBar.add(sendCommand);
 
		JMenuItem openAction = new JMenuItem("Load new map");
		JMenuItem exitAction = new JMenuItem("Exit");
 
		JMenuItem sendcmd = new JMenuItem("Send command");
		setVisible(true);
 
 
		sendCommand.add(sendcmd);
		fileMenu.add(openAction);
		fileMenu.addSeparator();
		fileMenu.add(exitAction);
 
 
		openAction.setActionCommand("open");  
		openAction.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent event) {
 
			}});
 
		exitAction.setActionCommand("exit");   
		exitAction.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent event) {
				System.exit(0);
			}});
 
 
		sendcmd.setActionCommand("sendcmd");
		sendcmd.addActionListener(new DialogSender());
 
 
 
 
		setVisible(true);
 
	}//end of constructor
 
 
	public static void main(String[] args){
		try {
			new Client();
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
 
 
 
	class DialogSender implements ActionListener {
		public void actionPerformed(ActionEvent ae) {
			PrintWriter outToServer = null; 
			try {
				outToServer = new PrintWriter(new OutputStreamWriter(
						clientSocket.getOutputStream()));
 
				String sentence = JOptionPane.showInputDialog("Send a command:");
				if (sentence!=null && sentence.trim().length()>0){
					/* send the sentence to the server */
					outToServer.println(sentence);
				}
				outToServer.flush();
			} catch (IOException e) {
				e.printStackTrace();
			} finally {
				try {
				} catch (Exception e) { 
				}
			}
		}
	}
 
 
 
}
Start your free trial to view this solution
[x]
The Solution Rating System

With so many solutions, how can you tell which solutions are most likely to help you and which ones are not? To provide you with a tool to use, we rate our solutions based on various elements that most accurately determine if a solution is a quality solution. To explain what factors affect the solution rating, here are the elements we take into consideration when formulating our solution rating.

  • The Grade of the Solution
  • The Zone Rank of the Expert Providing the Solution
  • The Number of Author and Expert Comments
  • The Number of Experts Contributing
  • The Feedback of the Community

Your Input Matters
Because of the way the system is set up, the most important variable in this equation is you. As a member of Experts Exchange, you are able to cast your vote on the quality of the solutions in regard to how complete, accurate, helpful and easy to understand each solution is. When you provide your feedback, each rating is adjusted accordingly. So, if you see a solution that has a poor rating that you think is a good solution, let us know by rating it. As you do, the rating will be adjusted and will become more accurate for other members of our site.

If you have any suggestions that you would like to make for our rating system, please ask a question in the Suggestions Zone of Community Support.

Thank you!
9.0
Question Stats
Zone: Programming
Question Asked By: perdoname_
Solution Provided By: MicheleMarcon
Participating Experts: 2
Solution Grade: A
Views: 0
Translate:
Loading Advertisement...
 
[+][-]Expert Comment by ksivananth

Rank: Sage

Expert Comment by ksivananth:

All comments and solutions are available to Premium Service Members only.

Start your 7-day free trial and see for yourself why Experts Exchange is the easiest and most proven technology resource in the world. Get Started

Already a member? Login to view this solution.

 
 
[+][-]Accepted Solution by MicheleMarcon

Rank: Master

Accepted Solution by MicheleMarcon:

All comments and solutions are available to Premium Service Members only.

Start your 7-day free trial and see for yourself why Experts Exchange is the easiest and most proven technology resource in the world. Get Started

Already a member? Login to view this solution.

 
 
Loading Advertisement...
20080723-EE-VQP-34 / EE_QW_2_20070628