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Java > Open Source Codes > org > enhydra > apache > xerces > dom > LCount


1 /*
2  * The Apache Software License, Version 1.1
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4  *
5  * Copyright (c) 1999 The Apache Software Foundation. All rights
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24  * Alternately, this acknowledgment may appear in the software itself,
25  * if and wherever such third-party acknowledgments normally appear.
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57 package org.enhydra.apache.xerces.dom;
58
59
60 /** Internal class LCount is used to track the number of
61     listeners registered for a given event name, as an entry
62     in a global hashtable. This should allow us to avoid generating,
63     or discard, events for which no listeners are registered.
64     
65     ***** There should undoubtedly be methods here to manipulate
66     this table. At the moment that code's residing in NodeImpl.
67     Move it when we have a chance to do so. Sorry; we were
68     rushed.
69     
70     ***** Also, I'm currently asking "are there any listeners"
71     by testing captures+bubbles+defaults =? 0. It would probably
72     make sense to have a separate "total" field, calculated at
73     add/remove, to save a few cycles during dispatch. Fix.
74     
75     ???? CONCERN: Hashtables are known to be "overserialized" in
76     current versions of Java. That may impact performance.
77     
78     ???? CONCERN: The hashtable should probably be a per-document object.
79     Finer granularity would be even better, but would cost more cycles to
80     resolve and might not save enough event traffic to be worth the investment.
81 */
82 class LCount
83 {
84     static java.util.Hashtable JavaDoc lCounts=new java.util.Hashtable JavaDoc();
85     public int captures=0,bubbles=0,defaults=0;
86
87     static LCount lookup(String JavaDoc evtName)
88     {
89         LCount lc=(LCount)lCounts.get(evtName);
90         if(lc==null)
91             lCounts.put(evtName,(lc=new LCount()));
92         return lc;
93     }
94 } // class LCount
95
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