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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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package com.sun.xml.internal.xsom.util;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.MessageFormat;
import java.util.ResourceBundle;
import java.util.WeakHashMap;

Simple utility ensuring that the value is cached only in case it is non-internal implementation
/** * Simple utility ensuring that the value is cached only in case it is non-internal implementation */
abstract class ContextClassloaderLocal<V> { private static final String FAILED_TO_CREATE_NEW_INSTANCE = "FAILED_TO_CREATE_NEW_INSTANCE"; private WeakHashMap<ClassLoader, V> CACHE = new WeakHashMap<ClassLoader, V>(); public V get() throws Error { ClassLoader tccl = getContextClassLoader(); V instance = CACHE.get(tccl); if (instance == null) { instance = createNewInstance(); CACHE.put(tccl, instance); } return instance; } public void set(V instance) { CACHE.put(getContextClassLoader(), instance); } protected abstract V initialValue() throws Exception; private V createNewInstance() { try { return initialValue(); } catch (Exception e) { throw new Error(format(FAILED_TO_CREATE_NEW_INSTANCE, getClass().getName()), e); } } private static String format(String property, Object... args) { String text = ResourceBundle.getBundle(ContextClassloaderLocal.class.getName()).getString(property); return MessageFormat.format(text, args); } private static ClassLoader getContextClassLoader() { return (ClassLoader) AccessController.doPrivileged(new PrivilegedAction() { public Object run() { ClassLoader cl = null; try { cl = Thread.currentThread().getContextClassLoader(); } catch (SecurityException ex) { } return cl; } }); } }