https://xerces.apache.org/xerces2-j/: Xerces2 is the next generation of high performance, fully compliant XML parsers in the Apache Xerces family. This new version of Xerces introduces the Xerces Native Interface (XNI), a complete framework for building parser components and configurations that is extremely modular and easy to program. The Apache Xerces2 parser is the reference implementation of XNI but other parser components, configurations, and parsers can be written using the Xerces Native Interface. For complete design and implementation documents, refer to the XNI Manual. Xerces2 is a fully conforming XML Schema 1.0 processor. A partial experimental implementation of the XML Schema 1.1 Structures and Datatypes Working Drafts (December 2009) and an experimental implementation of the XML Schema Definition Language (XSD): Component Designators (SCD) Candidate Recommendation (January 2010) are provided for evaluation. For more information, refer to the XML Schema page. Xerces2 also provides a complete implementation of the Document Object Model Level 3 Core and Load/Save W3C Recommendations and provides a complete implementation of the XML Inclusions (XInclude) W3C Recommendation. It also provides support for OASIS XML Catalogs v1.1. Xerces2 is able to parse documents written according to the XML 1.1 Recommendation, except that it does not yet provide an option to enable normalization checking as described in section 2.13 of this specification. It also handles namespaces according to the XML Namespaces 1.1 Recommendation, and will correctly serialize XML 1.1 documents if the DOM level 3 load/save APIs are in use. 
/*
 * 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.xerces.dom;


/** Internal class LCount is used to track the number of
    listeners registered for a given event name, as an entry
    in a global hashtable. This should allow us to avoid generating,
    or discard, events for which no listeners are registered. 
    
    ***** There should undoubtedly be methods here to manipulate
    this table. At the moment that code's residing in NodeImpl.
    Move it when we have a chance to do so. Sorry; we were
    rushed.
    
    ???? CONCERN: Hashtables are known to be "overserialized" in
    current versions of Java. That may impact performance.
    
    ???? CONCERN: The hashtable should probably be a per-document object.
    Finer granularity would be even better, but would cost more cycles to
    resolve and might not save enough event traffic to be worth the investment.
*/

@xerces.internal
Version:$Id: LCount.java 447266 2006-09-18 05:57:49Z mrglavas $
/**
 * @xerces.internal

 * 
 * @version $Id: LCount.java 447266 2006-09-18 05:57:49Z mrglavas $
 */

class LCount 
{ 
    static java.util.Hashtable lCounts=new java.util.Hashtable();
    public int captures=0,bubbles=0,defaults, total=0;

    static LCount lookup(String evtName)
    {
        LCount lc=(LCount)lCounts.get(evtName);
        if(lc==null)
            lCounts.put(evtName,(lc=new LCount()));
        return lc;	        
    }
} // class LCount