onteventmanager.java

jena2.5.4推理机系统的一种最基本实现 HP实验室出品

     * @param arg2 The third argument to the event, or null
     */
    public void raise( Resource event, boolean added, Model source, RDFNode arg0, RDFNode arg1, RDFNode arg2 ) {
        OntEventHandler h = getHandler( event );
        if (h != null) {
            h.action( event, added, source, arg0, arg1, arg2 );
        }
        else if (m_defaultHandler != null) {
            // if no assigned handler, call the default handler
            m_defaultHandler.action( event, added, source, arg0, arg1, arg2 );
        }
    }
    
    
    /**
     * <p>Add the given handler as the default event handler, which will be invoked if
     * no other handler is applicable to a given event.</p>
     * @param handler The event handler object
     */
    public void addDefaultHandler( OntEventHandler handler ) {
        m_defaultHandler = handler;
    }   


    /**
     * <p>Add the given handler as the handler for the given event type, replacing
     * any existing handler.</p>
     * @param event The event type to be handled, as a resource
     * @param handler The event handler object
     */
    public void addHandler( Resource event, OntEventHandler handler ) {
        m_handlers.put( event, handler );
    }   


    /**
     * <p>Add the given handlers as the handler for the given event types, replacing
     * any existing handlers.</p>
     * @param handlers An array of pairs, where the first element of each pair
     * is the resource denoting the event to be handled, and the second is the 
     * handler object
     */
    public void addHandlers( Object[][] handlers ) {
        for (int i = 0;  i < handlers.length;  ) {
            Resource r = (Resource) handlers[i][0];
            OntEventHandler h = (OntEventHandler) handlers[i][1];
            addHandler( r, h );
        }
    }   

    /**
     * <p>Answer the event handler for the given event, or null if not defined</p>
     * @param event An event type to look up
     * @return The current handler for the event, or null
     */
    public OntEventHandler getHandler( Resource event ) {
        return (OntEventHandler) m_handlers.get( event );
    }   


    /**
     * <p>Answer the default event handler, or null if not defined</p>
     * @return The default event handler, or null
     */
    public OntEventHandler getDefaultHandler() {
        return m_defaultHandler;
    }   


    /**
     * <p>Remove any existing handler for the given event type.</p>
     * @param event The event for which the handler is to be removed
     */
    public void removeHandler( Resource event ) {
        m_handlers.remove( event );
    }   


    /**
     * <p>Answer true if there is a defined handler for the given event type.</p>
     * @param event An event type, as a resource
     * @return True if there is a defined handler for the event
     */
    public boolean hasHandler( Resource event ) {
        return m_handlers.containsKey( event );
    }   
    
    
    /**
     * <p>Answer an iterator over the events that are registered in this
     * event manager.</p>
     * @return An iterator over the event types of events that have registered handlers
     */
    public Iterator listRegisteredEvents() {
        return m_handlers.keySet().iterator();
    }
    
    
    // Internal implementation methods
    //////////////////////////////////

    /**
     * <p>Initialise the given map from static initialisation data. This will be a mapping
     * that allows us to determine the correct ontology event type for a given triple.</p>
     * @param map The map to update
     * @param p An ontology language profile
     * @param source A table of initialisation data
     */
    private void initialiseTable( Map map, Profile p, Object[][] source ) {
        for (int i = 0;  i < source.length;  i++) {
            // get the initialisation data from the table
            Resource evType = (Resource) source[i][0];
            Resource key = ((ProfileAccessor) source[i][1]).get( p );
            
            if (key != null) {
                // is defined for this term
                map.put( key, evType );
            }
        }
    }
    
    
    /**
     * <p>Process an incoming added or removed statement to raise the appropriate ontology event.</p>
     * @param s
     * @param added
     */
    private void processStatement( Statement s, boolean added ) {
        // first check if this an rdf:type statement
        if (s.getPredicate().equals( RDF.type )) {
            // yes - now is it a builtin type?
            Resource type = s.getResource();
            Resource evType = (Resource) m_rdfTypeToEventType.get( type );
            
            if (evType != null) {
                // was a known type, so we know which event to raise
                raise( evType, added, s.getModel(), s.getSubject(), null, null );
            }
            else {
                // must be an individual
                raise( OntEventsVocab.individualDeclaration, added, s.getModel(), s.getSubject(), type, null );
            }
        }
        else {
            // not rdf:type, but may still be a known predicate
            Property pred = s.getPredicate();
            Resource evType = (Resource) m_predicateToEventType.get( pred );
            
            if (evType != null) {
                // was a known predicate, so we know which event to raise
                raise( evType, added, s.getModel(), s.getSubject(), s.getObject(), null );
            }
            else {
                // default - assume user data
                raise( OntEventsVocab.userData, added, s.getModel(), s.getSubject(), pred, s.getObject() );
            }
        }
    }
    
    
    //==============================================================================
    // Inner class definitions
    //==============================================================================

    /** Simple wrapper to allow us to dynamically extract elements from the profile */
    private static interface ProfileAccessor {
        public Resource get( Profile p );
    }
}


/*
 *  (c) Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007 Hewlett-Packard Development Company, LP
 *  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */