Ubuntu 9.10 screen flashing and keyboard unresponsive

2009-10-30

If Ubuntu 9.10 boots up to a flashing screen and unresponsive keyboard chances are your xwindows configuration isn't working - you can check this by running /etc/init.d/gdm stop (you should have a nice non-flashing shell)

for some reason dpkg-reconfigure xserver-xorg didn't work for but simply deleting /etc/X11/xorg.conf did - all should be fine after a reboot

Ubuntu alsa-utils sound Issues

2009-10-22

Alsa-Utils sound in Ubuntu 8+ is buggy as hell and always seems to die on me When the sound goes all crackly and

m@m:~$ /etc/init.d/alsa-utils restart

doesn't work; try

m@m:~$ /etc/init.d/alsa-utils reset

other params are:
{start [CARD]|stop [CARD]|restart [CARD]|reset [CARD]}

PHP Hash Maker - MD5, SHA1 etc

2009-08-22

The Hash maker is a quick and easy way to either make hashes and use them directly or try to work out what your lost password was

I find it quite useful to be able to generate hashes for passwords directly for the purposes of resetting passwords directly in a database

Bluetooth connection manager in Mobile Java J2ME

2009-03-17

This Bluetooth Java connection manager class and its data package class have quite a few issues - main one being that the thread for checking the incoming data stream should be reading each byte of data and queuing it rather than trying to receive discrete packages of data and queueing them - will be fixed and updated at some stage.

/*
* copyright - mike lang - icurtain.co.uk
* blutooth connection manager - 0.1
* has some rather dodgy flaws - multi-threading is currently incorrectly implemented
*
*/
package utilities;
// Bluetooth Libraries
import javax.bluetooth.*;
import javax.microedition.io.*;
import java.io.*;
import java.util.Vector;
/**
*
* @author mike lang
*/
public class ConnectionManager implements Runnable {
//bluetooth vars
public LocalDevice local;
public StreamConnectionNotifier notifier;
public DiscoveryAgent agent;
private boolean active = false;
private boolean server = false;
private int packetSize = 15;
boolean tx = false;
//new stuff
private String btSerial = "86b4d249fb8844d6a756ec265dd1f6a3";
//output stream to write to
private StreamConnection streamConnection;
private ServiceRecord serviceRecord;
private OutputStream outputStream;
//input stream fromw hich to read
private InputStream inputStream;
private Vector sendQueue;
private Vector receiveQueue;
private boolean threadQuit;
private String dataStart = "<";
private String dataStop = ">";
private String dataBreak = "@";
private String incompleteData;
private int threadSleep = 100;
public void run(){
while(!threadQuit){
if(this.isActive()){
this.communicate();
}
// System.out.println("COMMS THREADLOOP");
try {
//Sleep for 100 milliseconds, or 1/10 of a //
Thread.sleep(threadSleep);
//second. The sleep method chucks up an //
} //exception. //
catch (Exception ee) {
System.out.println(ee);
}
}
}
public synchronized void addSendQueue(BTPackage btp){
//we are typing the list info as Strings
if(sendQueue==null){
sendQueue = new Vector();
}
//now its in the queue calc the checksum
btp.calcCheckSum();
sendQueue.addElement(new BTPackage(btp));
}
private BTPackage consumeSendQueue(){
//we can either type to string or just store objects
if(sendQueue != null && !sendQueue.isEmpty()){
BTPackage btp = (BTPackage)sendQueue.lastElement();
sendQueue.removeElement(sendQueue.lastElement());
return btp;
}
return null;
}
private void addRecieveQueue(BTPackage btp){
if(receiveQueue==null){
receiveQueue = new Vector();
}
receiveQueue.addElement(new BTPackage(btp));
}
public synchronized boolean checkReceiveQueue(){
if(receiveQueue != null && !receiveQueue.isEmpty()){
return true;
}return false;
}
public synchronized BTPackage getReceiveQueue(){
//we can either type to string or just store objects
if(this.checkReceiveQueue()){
BTPackage btp = (BTPackage)receiveQueue.lastElement();
receiveQueue.removeElement(receiveQueue.lastElement());
return btp;
}return null;
}
//code here
public void setBtSerial(String btSerial){
this.btSerial = btSerial;
}
public String getBtSerial(){
return this.btSerial;
}
private void setActive(boolean active){
this.active = active;
}
public boolean isActive(){
return this.active;
}
public boolean isServer() {
return server;
}
private void setServer(boolean server) {
this.server = server;
}
public void startServer(){
// server code
if(!this.isActive()){
try {
local = LocalDevice.getLocalDevice();
if (!local.setDiscoverable(DiscoveryAgent.GIAC)) {
System.out.println("Failed to change to the discoverable mode");
return;
}
notifier = (StreamConnectionNotifier) Connector.open("btspp://localhost:" + this.getBtSerial());
// System.out.println("btspp://localhost:" + this.getBtSerial());
streamConnection = (StreamConnection) notifier.acceptAndOpen();
inputStream = streamConnection.openInputStream();
//may have to remove this line below;
outputStream =streamConnection.openOutputStream();
//ByteArrayOutputStream out = new ByteArrayOutputStream();
this.setActive(true);
this.setServer(true);
ByteArrayOutputStream out = new ByteArrayOutputStream();
} catch (BluetoothStateException e){
System.out.println("BluetoothStateException:" + e.getMessage());
} catch (IOException e){
System.out.println("IOException:" + e.getMessage());
}
}
}
public void startClient(){
try {
agent = LocalDevice.getLocalDevice().getDiscoveryAgent();
String connectionString = agent.selectService(
new UUID(btSerial, false),
ServiceRecord.NOAUTHENTICATE_NOENCRYPT, false);
if (connectionString != null) {
// System.out.println("trying to send bluetooth client data");
try {
streamConnection = (StreamConnection) Connector.open(connectionString);
outputStream = streamConnection.openOutputStream();
inputStream = streamConnection.openInputStream();
System.out.println("initiating a connection");
this.setActive(true);
this.setServer(false);
} catch (IOException e) {
System.out.println("IOException:" + e.getMessage());
}
} else {
System.out.println("Unable To Locate Service");
}
} catch (BluetoothStateException e){
System.out.println("BluetoothStateException:" + e.getMessage());
}
}
private void communicate(){
// synchronized( this ){
System.out.println("network thread");
if(this.isServer()) {
this.sendData();
this.receiveData();
}else{
this.receiveData();
this.sendData();
}
// }
}
private void sendData(){
//OutputStream outputStream = streamConnection.openOutputStream();
String data = "";
//we should be consuming the send queue here
if((this.sendQueue != null)&&(!this.sendQueue.isEmpty())){
data = this.encodeBTPackage(this.consumeSendQueue());
System.out.println("SENDING:" + data);
if (this.streamConnection != null) {
// System.out.println("trying to send bluetooth client data");
try {
//data = dataStart+data+dataStop;
outputStream.write(data.getBytes());
} catch (IOException e) {
System.out.println("IOException:" + e.getMessage());
}
}
//set to receive
}
}
private void receiveData(){
byte[] dataBuffer;
String tempData = "";
boolean endOfPackage = false;
int input;
try {
while ((input = inputStream.read()) >= 0){
//System.out.println("XX "+(char) input);
tempData += (char) input;
//THIS SECTION MUST RELINQUISH READING OR IT WILL CARRY ON READING THE WHOLE OUTPUTSTREAM!!!!
if(String.valueOf((char)input).equals(dataStop)){
// this.addRecieveQueue(tempData);
// System.out.println("ADDED: "+ tempData);
// return;
break;
}
}
System.out.println("PROCESSED: "+ tempData);
this.addRecieveQueue(this.unencodeBTPackage(tempData));
} catch (IOException ex) {
ex.printStackTrace();
}
}
public void terminate(){
try{
this.streamConnection.close();
}catch(IOException e){
System.out.println(e.toString());
}
this.setActive(false);
}
public boolean isThreadQuit() {
return threadQuit;
}
public void setThreadQuit(boolean threadQuit) {
this.threadQuit = threadQuit;
}
private String encodeBTPackage(BTPackage data){
String string = "";
data.calcCheckSum();
string = this.dataStart +
data.getNameSpace() +
this.dataBreak +
data.getData() +
this.dataBreak +
String.valueOf(data.getCheckSum()) +
this.dataBreak +
String.valueOf(data.getTime()) +
this.dataStop;
return string;
}
private BTPackage unencodeBTPackage(String data){
//we are currently using 4 fields so the string has to be split into an array
Vector list = new Vector();
String temp = "";
// temp = data.substring(packetSize, packetSize)
//split string into array
int j = 0;
//this loop checks for the data break and if it finds it creates
for(int i = 1;i<(data.length()-1);i++){
if(!data.substring(i,(i+1)).equals(this.dataBreak)){
temp += data.substring(i,(i+1));
}else{
list.addElement(new String(temp));
temp = "";
j++;
//System.out.println(data.substring(i,(i+1)));
}
}
//catch the last list element here rather than doing a double compare in the if
list.addElement(new String(temp));
/*for(int i = 0; i < list.size();i++){
System.out.println((String)list.elementAt(i));
}*/
BTPackage btp = new BTPackage();
btp.setNameSpace((String)list.elementAt(0));
btp.setData((String)list.elementAt(1));
//the quickest way seems to be to convert from object cast as String to long
//btp.setTime(Long.parseLong((String) list.elementAt(2)));
//btp.setCheckSum(Long.parseLong((String)list.elementAt(3)));
return btp;
}
}
/*
* copyright - mike lang - icurtain.co.uk
* blutooth connection manager - 0.1
* data package
*/
package utilities;
/**
*
* @author mike lang
*/
public class BTPackage {
//live variable says if the data package is live or
private boolean live = true;
private String nameSpace = "";
private String data = "";
private long checkSum;
private long time;
public BTPackage(){
this.time = System.currentTimeMillis();
}
//alternate constructor
public BTPackage(BTPackage btp){
this.setNameSpace(btp.getNameSpace());
this.setData(btp.getData());
this.setTime(btp.getTime());
this.setCheckSum(btp.getCheckSum());
}
public String getData() {
return data;
}
public void setData(String data) {
this.data = data;
}
public boolean isLive() {
return live;
}
public void setLive(boolean live) {
this.live = live;
}
public String getNameSpace() {
return nameSpace;
}
public void setNameSpace(String nameSpace) {
this.nameSpace = nameSpace;
}
public void calcCheckSum(){
this.checkSum = String.valueOf(this.time+this.nameSpace).hashCode();
}
public void setCheckSum(long checkSum){
//this should only be called before the package is sent
this.checkSum = checkSum;
}
public long getCheckSum(){
//this should only be called before the package is sent
//this.checkSum = String.valueOf(this.time+this.nameSpace).hashCode();
return this.checkSum;
}
public long getTime() {
return time;
}
public void setTime(long time) {
this.time = time;
}
}

find java path in ubuntu

2008-12-08

finding the java path in ubuntu is easy, just follow the links... most links live in /usr/bin so:

mike@mbox:/$ ls -l /usr/bin/java
lrwxrwxrwx 1 root root 22 2008-12-07 22:16 /usr/bin/java -> /etc/alternatives/java

mike@mbox:/$ ls -l /etc/alternatives/java
lrwxrwxrwx 1 root root 40 2008-12-07 22:34 /etc/alternatives/java -> /usr/lib/jvm/java-6-openjdk/jre/bin/java