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yacy_search_server/source/net/yacy/document/LargeNumberCache.java

58 lines
2.2 KiB

/**
* LargeNumberCache.java
* Copyright 2010 by Michael Peter Christen, mc@yacy.net, Frankfurt am Main, Germany
* First released 09.10.2010 at http://yacy.net
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program in the file lgpl21.txt
* If not, see <http://www.gnu.org/licenses/>.
*/
package net.yacy.document;
/**
* a LargeIntegerCache is used whenever a Integer.valueOf(int i) is used.
* The Integer java class provides a cache for values from -128 to +127
* which is not enough for the parser to organize word positions in texts
* Using this large cache the parser has a lower memory allocation and is faster.
*/
public class LargeNumberCache {
private static final int integerCacheLimit = 3000;
private static final Integer integerCache[];
// fill the cache
static {
integerCache = new Integer[integerCacheLimit];
for (int i = 0; i < integerCache.length; i++) integerCache[i] = new Integer(i);
}
/**
* Returns a Integer instance representing the specified int value.
* If a new Integer instance is not required, this method
* should generally be used in preference to the constructor
* {@link #Integer(int)}, as this method is likely to yield
* significantly better space and time performance by caching
* frequently requested values.
*
* @param i an int value.
* @return a Integer instance representing i.
*/
public final static Integer valueOf(final int i) {
if (i < 0) return Integer.valueOf(i);
if (i >= integerCacheLimit) return new Integer(i);
return integerCache[i];
}
}