AbstractStanzaHandlerLookup.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 *
 */
package org.apache.vysper.xmpp.protocol;

import java.util.ArrayList;
import java.util.List;

import org.apache.vysper.xml.fragment.XMLElement;
import org.apache.vysper.xmpp.stanza.Stanza;

/**
 * basic facility to collect and query a set of namespace-based handlers 
 */
public abstract class AbstractStanzaHandlerLookup {
    protected List<HandlerDictionary> namespaceDictionaries = new ArrayList<HandlerDictionary>();

    public void addDictionary(HandlerDictionary namespaceHandlerDictionary) {
        namespaceDictionaries.add(namespaceHandlerDictionary);
    }

    public abstract StanzaHandler getHandler(Stanza stanza);

    /**
     * tries to find the handler by trying
     * 1. value of xmlElement's XMLNS attribute, if unique
     * 2. xmlElements namespace, if the element name has a namespace prefix
     */
    protected StanzaHandler getHandlerForElement(Stanza stanza, XMLElement xmlElement) {
        for(HandlerDictionary dictionary : namespaceDictionaries) {
            StanzaHandler stanzaHandler = dictionary.get(stanza);
            if(stanzaHandler != null) return stanzaHandler;
        }
        return null;
    }
}