package org.jacorb.notification.util;
/*
* JacORB - a free Java ORB
*
* Copyright (C) 1999-2014 Gerald Brose / The JacORB Team.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
/**
* Add Caching to WildcardMap. If the Keys inside the Map contain the Wildcard Operator '*' the
* Operation getWithExpansion is rather timeconsuming. For each Key that contains a '*' a pattern
* match must be done. This Decorator adds simple Caching. When a key is looked up the retrieved
* value is stored in an internal cache with fixed size. Subsequent calls to getWithExpansion query
* the cache first. As soon as a put or remove Operation occurs the Cache is invalidated.
*
* @author Alphonse Bendt
*/
public class CachingWildcardMap implements WildcardMap
{
private final Object[] cachedKeys_;
private final Object[][] cachedValues_;
private Object victimKey_;
private Object[] victimValue_;
private final int cacheSize_;
private final WildcardMap delegate_;
public CachingWildcardMap()
{
this(4, new DefaultWildcardMap());
}
public CachingWildcardMap(int cacheSize, WildcardMap delegate)
{
super();
cachedValues_ = new Object[cacheSize][];
cachedKeys_ = new Object[cacheSize];
cacheSize_ = cacheSize;
delegate_ = delegate;
}
private int calcPosition(String key)
{
return key.charAt(0) % cacheSize_;
}
private void invalidateCache()
{
for (int x = 0; x < cacheSize_; ++x)
{
cachedKeys_[x] = null;
}
victimKey_ = null;
}
public void clear()
{
invalidateCache();
delegate_.clear();
}
public Object remove(Object key)
{
invalidateCache();
return delegate_.remove(key);
}
public Object put(Object key, Object value)
{
invalidateCache();
return delegate_.put(key, value);
}
public Object[] getWithExpansion(Object key)
{
String _key = key.toString();
int _pos = calcPosition(_key);
Object[] _ret;
if (_key.equals(cachedKeys_[_pos]))
{
_ret = cachedValues_[_pos];
}
else if (_key.equals(victimKey_))
{
_ret = victimValue_;
}
else
{
_ret = delegate_.getWithExpansion(key);
// store old cache entry in victim cache
victimKey_ = cachedKeys_[_pos];
victimValue_ = cachedValues_[_pos];
// update cache entry
cachedKeys_[_pos] = _key;
cachedValues_[_pos] = _ret;
}
return _ret;
}
/*
* (non-Javadoc)
*
* @see org.jacorb.notification.util.WildcardMap#getNoExpansion(java.lang.Object)
*/
public Object getNoExpansion(Object key)
{
return delegate_.getNoExpansion(key);
}
}