IncomingRequestParser.java

package com.serotonin.bacnet4j.npdu;

import com.serotonin.bacnet4j.apdu.APDU;
import com.serotonin.bacnet4j.event.ExceptionDispatch;
import com.serotonin.bacnet4j.exception.BACnetException;
import com.serotonin.bacnet4j.type.constructed.Address;
import com.serotonin.bacnet4j.type.constructed.ServicesSupported;
import com.serotonin.bacnet4j.type.primitive.OctetString;
import org.free.bacnet4j.util.ByteQueue;

abstract public class IncomingRequestParser {
    private final Network network;
    protected final ByteQueue originalQueue;
    protected final ByteQueue queue;
    protected Address from;
    protected OctetString linkService;
    protected ServicesSupported servicesSupported;

    protected IncomingRequestParser(Network network, ByteQueue queue, OctetString localFrom) {
        this.network = network;
        this.queue = queue;
        this.originalQueue = (ByteQueue) queue.clone();
        linkService = localFrom;
    }

    public void run() {
        try {
            // Determine the supported services. Logical branch supports testing.
            if (network == null || network.getTransport() == null) {
                // Testing
                servicesSupported = new ServicesSupported();
                servicesSupported.setAll(true);
            }
            else
                servicesSupported = network.getTransport().getLocalDevice().getServicesSupported();

            parseFrame();

            // Create the APDU.
            APDU apdu = parseApdu();
            if (apdu != null && network != null) {
                if (network.isLocal(from))
                    linkService = null;
                network.getTransport().incomingApdu(apdu, from, linkService);
            }
        }
        catch (Exception e) {
            ExceptionDispatch.fireReceivedException(e);
        }
        catch (Throwable t) {
            ExceptionDispatch.fireReceivedThrowable(t);
        }
    }

    /**
     * Parse out the network-specific data up until the NPCI.
     * 
     * @throws MessageValidationAssertionException
     */
    abstract protected void parseFrame() throws MessageValidationAssertionException;

    public APDU parseApdu() throws Exception {
        // Network layer protocol control information. See 6.2.2
        NPCI npci = new NPCI(queue);
        if (npci.getVersion() != 1)
            throw new MessageValidationAssertionException("Invalid protocol version: " + npci.getVersion());
        if (npci.isNetworkMessage())
            return null; // throw new MessageValidationAssertionException("Network messages are not supported");

        // Check the destination network number work and do not respond to foreign networks requests  
        if (npci.hasDestinationInfo()) {
            int destNet = npci.getDestinationNetwork();
            if (destNet > 0 && destNet != 0xffff && network.getLocalNetworkNumber() > 0
                    && network.getLocalNetworkNumber() != destNet)
                return null;
        }

        if (npci.hasSourceInfo())
            from = new Address(npci.getSourceNetwork(), npci.getSourceAddress());
        else
            from = new Address(linkService);

        // Create the APDU.
        try {
            return APDU.createAPDU(servicesSupported, queue);
        }
        catch (BACnetException e) {
            // If it's already a BACnetException, don't bother wrapping it.
            throw e;
        }
        catch (Exception e) {
            throw new BACnetException("Error while creating APDU: ", e);
        }
    }
}