Notify() not working

Question

Hi,
I'm developing a server using multi threading. But I'm have problem with notify() and wait() methods.
When I'm notify to thread, it will not start and i cant see any exceptions
public PResponseRequestQueue( String requestHandlerClassName,
int maxQueueLength,
int minThreads,
int maxThreads )
this.requestHandlerClassName = requestHandlerClassName;
this.maxQueueLength = maxQueueLength;
this.minThreads = minThreads;
this.maxThreads = maxThreads;
this.currentThreads = this.minThreads;
for( int i=0; i<this.minThreads; i++ )
PResponseRequestThread thread = new PResponseRequestThread( this,i, requestHandlerClassName );
thread.start();
this.threadPool.add( thread );
public synchronized void doWait(PResponseRequestThread reth)throws Exception{
     while (!waitHandler){
     reth.wait();
     waitHandler = false;
public synchronized void doWaitForChannelTimeout(long time)throws Exception{
     while (!waitTimeOutHandler){
     wait(time);
     waitTimeOutHandler = false;
public synchronized void add( Object o)
     boolean availableThread = false;
     for( int i=0;i<threadPool.size();i++ )
          rthread = ( PResponseRequestThread )threadPool.get(i);
     if( !rthread.isProcessingFlag() )
     System.out.println( "Found an available thread from p_response_runner pool for processing of incoming response.." );
     availableThread = true;
     break;
     System.out.println( "Thread no [ "+rthread.getThreadNumber()+" ] is busy in p_response_runner pool.." );
     if( !availableThread )
     if( this.currentThreads < this.maxThreads )
     System.out.println( "Creating a new thread of p_response_runner pool to satisfy the incoming responset" );
     rthread = new PResponseRequestThread( this, currentThreads++, this.requestHandlerClassName );
     rthread.start();
     this.threadPool.add( rthread );
     else
     System.out.println( "Can’t grow the thread pool in p_response_runner , guess you have to wait little while" );
     TxnKeyWord keywd = (TxnKeyWord)o;
               rthread.setKeyWD(keywd);
     synchronized (rthread) {
               try {
                              waitHandler = true;
                              rthread.notify();
                    } catch (Exception e) {
                         e.printStackTrace();
--------------------------------------------

Answer 1

Hi,
Just I have changed something of my code. that is the wait () method puts into the thread class.
01. This class will create the thread and put into arrayList. And also once request is receiving notification will take place in add() method
public class PResponseRequestQueue
    private int maxQueueLength;
    private  int minThreads; 
    private int maxThreads;
    private int currentThreads = 0;
    private String requestHandlerClassName;
    private static List threadPool = new ArrayList();
    private PResponseRequestThread rthread = null;
    public PResponseRequestQueue( String requestHandlerClassName,
                         int maxQueueLength,
                         int minThreads,
                         int maxThreads )
        this.requestHandlerClassName = requestHandlerClassName;
        this.maxQueueLength = maxQueueLength;
        this.minThreads = minThreads;
        this.maxThreads = maxThreads;
        this.currentThreads = this.minThreads;
        for( int i=0; i<this.minThreads; i++ )
            PResponseRequestThread thread = new PResponseRequestThread( this,i, requestHandlerClassName );
            thread.start();
            this.threadPool.add( thread );
    public synchronized void add( Object o)
             boolean availableThread = false;
             for( int i=0;i<threadPool.size();i++ )
                  rthread = ( PResponseRequestThread )threadPool.get(i);
                 if( !rthread.isProcessingFlag() )
                     System.out.println( "Found an available thread from p_response_runner pool for processing of incoming response.." );
                     availableThread = true;
                     break;
                 System.out.println( "Thread no [ "+rthread.getThreadNumber()+" ] is busy in p_response_runner pool.." );
             if( !availableThread )
                 if( this.currentThreads < this.maxThreads )
                     System.out.println( "Creating a new thread of p_response_runner pool to satisfy the incoming responset" );
                     rthread = new PResponseRequestThread( this, currentThreads++, this.requestHandlerClassName );
                     rthread.start();
                     this.threadPool.add( rthread );
                 else
                     System.out.println( "Can’t grow the thread pool in p_response_runner , guess you have to wait little while" );
             TxnKeyWord keywd = (TxnKeyWord)o;
          rthread.setKeyWD(keywd);
           synchronized (rthread) {
                   try {
                                   rthread.notify();
                    } catch (Exception e) {
                         e.printStackTrace();
}02 this is my thread class
import org.jpos.iso.ISOUtil;
import com.epic.line.logs.LogFileCreator;
import com.epic.line.logs.TestLoger;
import com.epic.line.modules.TxnKeyWord;
import com.epic.line.util.util.CurrentEexcution;
public class PResponseRequestThread extends Thread implements Comparable
     private PResponseRequestQueue queue;
    private TxnKeyWord keyWD;
    private boolean processing = false;
    private int threadNumber;
    private PResponseRequestHandler requestHandler;
    private long queue_time;
     public synchronized int getThreadNumber() {
          return threadNumber;
     public TxnKeyWord getKeyWD() {
          return this.keyWD;
     public void setKeyWD(TxnKeyWord keyWD) {
          this.keyWD = keyWD;
     public long getQueue_time() {
          return queue_time;
     public void setQueue_time(long queueTime) {
          queue_time = queueTime;
     public PResponseRequestThread(PResponseRequestQueue que, int threadNumber, String requestHandlerClassName )
        this.queue = que;
        this.threadNumber = threadNumber;
        try
            this.requestHandler = ( PResponseRequestHandler )( Class.forName( requestHandlerClassName ).newInstance() );
        catch( Exception e )
    public boolean isProcessingFlag()
        return this.processing;
    private PResponseRequestThread requestThread;
     public void run()
         this.processing = false;
         synchronized (this) {
             while( true )
                  this.processing = false;
                 try
                           this.processing = false;
                           this.wait();
                           this.processing = true;
                         this.queue_time = System.nanoTime();
                         System.out.println( "[Processing thread number in p_response_runner " + threadNumber + "]: Processing response ........" );
                         CurrentEexcution.incrP_r_exection();
                         this.wait(getKeyWD().getCHANNEL_TIME_OUT());
                         this.requestHandler.handleRequest( getKeyWD() );
                         System.out.println( "[Processing thread number in p_response_runner " + threadNumber + "]: Finished Processing response ......." );
                 catch( Exception e )
                    System.out.println("\nError is being detected while p_response_runner thread no [ "+threadNumber+" ]  is processing in p_response_runner thread.. \n");
                    LogFileCreator.writErrorTologs(e,this.keyWD);
                 }finally{
                      System.out.println("\nProcessing thread no [ "+threadNumber+" ] in p_response_runner pool returns back to the p_response_runner threads pool....\n");
                      CurrentEexcution.decrP_r_exection();
                      System.out.println("p_response_runner final countor "+CurrentEexcution.getP_r_exection());
                      setKeyWD(null);
                      setQueue_time(0);
                      this.processing = false;
    }handleRequest is the my interface
My problem is that,
When I am notify to thread (If isProcessingFlag = false), it will not start at that time but when I trace some "println", It has started after little time
Regards
Edited by: user10070648 on Dec 20, 2010 11:01 PM