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  • hi,
    when the bacnet4j app monitors other bacnet devices (notifications and cov) then detecting a doi collision gets important.
    when two davices do have the same doi then one device will miss event data.

    the iamrequest.java has to be modified as follows:

    
       /**
         * see if the address is my own local echo
         * 
         * @param from
         * @return
         */
        private boolean localEcho(Address from, Address[] localAddresses)
        {
        	for ( Address addr : localAddresses)
        	{
        		boolean equal = addr.equals(from);
        		if (equal)
        		{
        			return true;
        		}
        	}
        	return false;
        }
        
       // modified
        @Override
        public void handle(LocalDevice localDevice, Address from, Network network) {
            // Make sure we're not hearing from ourselves.
        	
        	int myDoi = localDevice.getConfiguration().getInstanceId();
        	int remoteDoi = iAmDeviceIdentifier.getInstanceNumber();
            if (remoteDoi == myDoi)
            {
            	// get my bacnet address and compare the addresses
            	Address[] myAddresses = localDevice.getAllLocalAddresses();
            	boolean lEcho = localEcho(from, myAddresses);
            	if ( lEcho)
            	{
            		return;
             	}
            	else
            	{
            		System.out.println("another instance with my doi found!");
            	}
            }
    
            // Register the device in the list of known devices.
            RemoteDevice d = localDevice.getRemoteDeviceCreate(remoteDoi, from, network);
            d.setMaxAPDULengthAccepted(maxAPDULengthAccepted.intValue());
            d.setSegmentationSupported(segmentationSupported);
            d.setVendorId(vendorId.intValue());
    
            // Fire the appropriate event.
            localDevice.getEventHandler().fireIAmReceived(d);
        }
    
    

    in localdevice.java is the function getLocalIPAdress, but we have multihomed linux boxes - a pain for java developers :wink:
    so we need to add a new function:

    
        public Address[] getAllLocalAddresses()
        {
            try 
            {
    	    	ArrayList<Address> lAddr = new ArrayList<Address>();
    	        for (NetworkInterface iface : Collections.list(NetworkInterface.getNetworkInterfaces())) {
    	            for (InetAddress addr : Collections.list(iface.getInetAddresses())) 
    	            {
    	                if (!addr.isLoopbackAddress() && addr.isSiteLocalAddress())
    	                {
    	                	byte[] addrBytes = addr.getAddress();
    	                	Address address = new Address(addrBytes, messageControl.getPort());
    	                	lAddr.add(address);
    	                }
    	             }
    	        }
    	  	    	
    	    	int elems = lAddr.size();
    	    	Address[] retVal = new Address[elems];
    	    	lAddr.toArray(retVal);
    	    	return retVal;
            }
            catch (Exception e) 
            {
                // Should never happen, so just wrap in a RuntimeException
                throw new RuntimeException(e);
            }
       }
    
    

    now you can easily detect if there is another device wioth the same doi:

    
    	public boolean isUniqueInstanceNumber()
    	{
    		int deviceID = getConfiguration().getInstanceId();
    		RemoteDevice rd = getRemoteDevice(deviceID);
    		if (null != rd)
    		{
    			return false;
    		}
    		else
    		{
    			return true;
    		}
    	}
    
    

    some functionality which is needed in our daily work.

    robert


  • Thanks Robert. This is been added in similar form to the code base. It imposed a difference to the public interface in LocalDevice though, in that the getAddress method now take an InetAddress parameter. The equivalent code is now:

    d.getAddress(d.getDefaultLocalInetAddress())
    

    All code changes have been checked into CVS.