| /* IntegerUtil.java -- JDK 5 Integer methods with 1.4 API |
| Copyright (C) 2006 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.security.util; |
| |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| |
| /** |
| * Utility class which offers Integer related methods found in RI's version 5 |
| * but written with RI's 1.4 API. |
| */ |
| public abstract class IntegerUtil |
| { |
| /** Maximum size of our cache of constructed Integers. */ |
| private static final int CACHE_SIZE = 100; |
| /** LRU (Least Recently Used) cache, of the last accessed 100 Integers. */ |
| private static final Map cache = new LinkedHashMap(CACHE_SIZE + 1, 0.75F, true) |
| { |
| public boolean removeEldestEntry(Map.Entry entry) |
| { |
| return size() > CACHE_SIZE; |
| } |
| }; |
| |
| /** Trivial private constructor to enforce Singleton usage. */ |
| private IntegerUtil() |
| { |
| super(); |
| } |
| |
| /** |
| * Similar to {@link Integer#valueOf(String)} except it caches the result in |
| * a local LRU cache of 100 elements, organized by access order. |
| * <p> |
| * This method MUST be used in the gnu.java.security and gnu.javax.crypto |
| * packages to ensure they would work with a version 1.4 only of the Java |
| * class library API. |
| * |
| * @param aString a string representation of an integer. |
| * @return the {@link Integer} object representing the designated string. |
| */ |
| public static final Integer valueOf(String aString) |
| { |
| Integer result; |
| synchronized (cache) |
| { |
| result = (Integer) cache.get(aString); |
| if (result == null) |
| { |
| result = Integer.valueOf(aString); |
| cache.put(aString, result); |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Simulates the <code>valueOf(int)</code> method found in {@link Integer} of |
| * the RI's version 1.5 using a local LRU cache of 100 elements, organized by |
| * access order. |
| * <p> |
| * This method MUST be used in the gnu.java.security and gnu.javax.crypto |
| * packages to ensure they would work with a version 1.4 only of the Java |
| * class library API. |
| * |
| * @param anInt a decimal integer. |
| * @return the {@link Integer} object representing the designated primitive. |
| */ |
| public static final Integer valueOf(int anInt) |
| { |
| return valueOf(Integer.toString(anInt, 10)); |
| } |
| } |