mirror of git://gcc.gnu.org/git/gcc.git
110 lines
3.8 KiB
Java
110 lines
3.8 KiB
Java
/* IntegerUtil.java -- JDK 5 Integer methods with 1.4 API
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Copyright (C) 2006 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package gnu.java.security.util;
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import java.util.LinkedHashMap;
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import java.util.Map;
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/**
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* Utility class which offers Integer related methods found in RI's version 5
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* but written with RI's 1.4 API.
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*/
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public abstract class IntegerUtil
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{
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/** Maximum size of our cache of constructed Integers. */
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private static final int CACHE_SIZE = 100;
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/** LRU (Least Recently Used) cache, of the last accessed 100 Integers. */
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private static final Map cache = new LinkedHashMap(CACHE_SIZE + 1, 0.75F, true)
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{
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public boolean removeEldestEntry(Map.Entry entry)
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{
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return size() > CACHE_SIZE;
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}
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};
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/** Trivial private constructor to enforce Singleton usage. */
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private IntegerUtil()
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{
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super();
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}
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/**
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* Similar to {@link Integer#valueOf(String)} except it caches the result in
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* a local LRU cache of 100 elements, organized by access order.
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* <p>
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* This method MUST be used in the gnu.java.security and gnu.javax.crypto
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* packages to ensure they would work with a version 1.4 only of the Java
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* class library API.
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*
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* @param aString a string representation of an integer.
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* @return the {@link Integer} object representing the designated string.
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*/
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public static final Integer valueOf(String aString)
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{
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Integer result;
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synchronized (cache)
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{
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result = (Integer) cache.get(aString);
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if (result == null)
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{
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result = Integer.valueOf(aString);
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cache.put(aString, result);
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}
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}
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return result;
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}
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/**
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* Simulates the <code>valueOf(int)</code> method found in {@link Integer} of
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* the RI's version 1.5 using a local LRU cache of 100 elements, organized by
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* access order.
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* <p>
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* This method MUST be used in the gnu.java.security and gnu.javax.crypto
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* packages to ensure they would work with a version 1.4 only of the Java
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* class library API.
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*
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* @param anInt a decimal integer.
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* @return the {@link Integer} object representing the designated primitive.
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*/
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public static final Integer valueOf(int anInt)
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{
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return valueOf(Integer.toString(anInt, 10));
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}
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}
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