SecurityUtil.java

  1. /**
  2.  *
  3.  * Copyright 2019 Florian Schmaus.
  4.  *
  5.  * Licensed under the Apache License, Version 2.0 (the "License");
  6.  * you may not use this file except in compliance with the License.
  7.  * You may obtain a copy of the License at
  8.  *
  9.  *     http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.jivesoftware.smack.util;

  18. import java.lang.reflect.InvocationTargetException;
  19. import java.security.Provider;
  20. import java.security.Security;

  21. import org.jxmpp.util.cache.LruCache;

  22. public class SecurityUtil {

  23.     private static final LruCache<Class<? extends Provider>, Void> INSERTED_PROVIDERS_CACHE = new LruCache<>(8);

  24.     public static void ensureProviderAtFirstPosition(Class<? extends Provider> providerClass) {
  25.         if (INSERTED_PROVIDERS_CACHE.containsKey(providerClass)) {
  26.             return;
  27.         }

  28.         Provider provider;
  29.         try {
  30.             provider = providerClass.getDeclaredConstructor().newInstance();
  31.         } catch (InstantiationException | IllegalAccessException | IllegalArgumentException | InvocationTargetException
  32.                 | NoSuchMethodException | SecurityException e) {
  33.             throw new IllegalArgumentException(e);
  34.         }

  35.         String providerName = provider.getName();

  36.         int installedPosition ;
  37.         synchronized (Security.class) {
  38.             Security.removeProvider(providerName);
  39.             installedPosition = Security.insertProviderAt(provider, 1);
  40.         }
  41.         assert installedPosition == 1;

  42.         INSERTED_PROVIDERS_CACHE.put(providerClass, null);
  43.     }
  44. }