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    • org.jgroups.blocks.mux.MuxUpHandler Maven / Gradle / Ivy

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    This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

    There is a newer version: 35.0.0.Beta1
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    package org.jgroups.blocks.mux;

import org.jgroups.Event;
import org.jgroups.Message;
import org.jgroups.UpHandler;
import org.jgroups.logging.Log;
import org.jgroups.logging.LogFactory;
import org.jgroups.util.ImmutableReference;
import org.jgroups.util.Util;

import java.util.Map;

/**
 * Allows up handler multiplexing.
 * 
 * @author Bela Ban
 * @author Paul Ferraro
 */
public class MuxUpHandler implements UpHandler, Muxer {

    protected final Log log=LogFactory.getLog(getClass());
    private final Map handlers=Util.createConcurrentMap();
    private volatile UpHandler defaultHandler;
    private volatile Event lastFlushEvent;
    private final Object flushMutex = new Object();
    
    /**
     * Creates a multiplexing up handler, with no default handler.
     */
    public MuxUpHandler() {
        this.defaultHandler = null;
    }

    /**
     * Creates a multiplexing up handler using the specified default handler.
     * @param defaultHandler a default up handler to handle messages with no {@link MuxHeader}
     */
    public MuxUpHandler(UpHandler defaultHandler) {
        this.defaultHandler = defaultHandler;
    }

    /**
     * {@inheritDoc}
     * @see org.jgroups.blocks.mux.Muxer#add(short, java.lang.Object)
     */
    @Override
    public void add(short id, UpHandler handler) {
        synchronized (flushMutex)
        {          
            if (lastFlushEvent != null)
            {
                handler.up(lastFlushEvent);
            }
            handlers.put(id, handler);
        }
    }

    /**
     * {@inheritDoc}
     * @see org.jgroups.blocks.mux.Muxer#get(short)
     */
    @Override
    public UpHandler get(short id) {
        return handlers.get(id);
    }
    
    /**
     * {@inheritDoc}
     * @see org.jgroups.blocks.mux.Muxer#remove(short)
     */
    @Override
    public void remove(short id) {
        handlers.remove(id);
    }

    @Override
    public UpHandler getDefaultHandler() {
        return defaultHandler;
    }

    @Override
    public void setDefaultHandler(UpHandler handler) {
        this.defaultHandler = handler;      
    }

   /**
     * {@inheritDoc}
     * @see org.jgroups.UpHandler#up(org.jgroups.Event)
     */
    @Override
    public Object up(Event evt) {
        switch (evt.getType()) {
            case Event.MSG:
                Message msg = (Message) evt.getArg();
                MuxHeader hdr = (MuxHeader) msg.getHeader(MuxRequestCorrelator.MUX_ID);
                if (hdr != null) {
                    short id = hdr.getId();
                    UpHandler handler = handlers.get(id);
                    return (handler != null) ? handler.up(evt) : new NoMuxHandler(id);
                }
                break;
            case Event.GET_APPLSTATE:
            case Event.GET_STATE_OK: 
            case Event.STATE_TRANSFER_OUTPUTSTREAM: 
            case Event.STATE_TRANSFER_INPUTSTREAM:
                ImmutableReference wrapper = handleStateTransferEvent(evt);
                if (wrapper != null)
                {
                   return wrapper.get();
                }
                break;
            case Event.BLOCK:
            case Event.UNBLOCK:
                synchronized (flushMutex)
                {
                   this.lastFlushEvent = evt;
                   passToAllHandlers(evt);
                   break;
                }
            case Event.VIEW_CHANGE:
            case Event.SET_LOCAL_ADDRESS: 
            case Event.SUSPECT:
                passToAllHandlers(evt);
                break;
            default:
                passToAllHandlers(evt);
                break;
        }
        
        return (defaultHandler != null) ? defaultHandler.up(evt) : null;
    }

    /**
      * Extension point for subclasses called by up() when an event
      * related to state transfer is received, allowing the subclass
      * to override the default behavior of passing the event to the
      * default up handler.
      *
      * @return an AtomicReference containing the return value for the event 
      *         if the event was handled and no further processing
      *         should be done in up(), or null if up() needs to 
      *         handle the event. If the event was handled but the return value 
      *         is null, an AtomicReference initialized to 
      *         null should be returned. This default 
      *         implementation always returns null
      */
    protected ImmutableReference handleStateTransferEvent(Event evt) {
         return null;
    } 
    
    

    private void passToAllHandlers(Event evt)
    {
       for (UpHandler handler: handlers.values()) {
            handler.up(evt);
        }
    }
}
    
    
    
    

    




    
    
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