deep-c-rsc/JCGO/goclsp/vm/java/lang/VMString.java
2021-07-16 17:12:20 -05:00

88 lines
2.8 KiB
Java

/*
* @(#) $(JCGO)/goclsp/vm/java/lang/VMString.java --
* VM specific methods for Java "String" class.
**
* Project: JCGO (http://www.ivmaisoft.com/jcgo/)
* Copyright (C) 2001-2008 Ivan Maidanski <ivmai@ivmaisoft.com>
* All rights reserved.
**
* Class specification origin: GNU Classpath v0.93 vm/reference
*/
/*
* This 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.
**
* This software 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 (GPL) for more details.
**
* 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 java.lang;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.WeakHashMap;
final class VMString /* hard-coded class name */
{
private static WeakHashMap internTable;
private static HashMap internLiteralTable;
private VMString() {}
static synchronized String intern(String str)
{
WeakHashMap table;
if ((table = internTable) == null)
{
String[] literals = getInitStrings0();
int len = literals != null ? literals.length : 0;
HashMap table2 = new HashMap(len / 3 + len + 1);
for (int i = 0; i < len; i++)
{
String s = literals[i];
if (s != null)
table2.put(s, s);
}
internLiteralTable = table2;
table = new WeakHashMap();
internTable = table;
}
Object obj = table.get(str);
if ((obj = obj != null ? ((WeakReference) obj).get() :
internLiteralTable.get(str)) != null)
return (String) obj;
if (str == null) /* hack */
throw new InternalError();
table.put(str, new WeakReference(str));
return str;
}
private static native
String[] getInitStrings0(); /* JVM-core */ /* const data */
}