1 /* 2 * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.security.jca; 27 28 import java.lang.ref.*; 29 30 import java.security.*; 31 32 /** 33 * Collection of static utility methods used by the security framework. 34 * 35 * @author Andreas Sterbenz 36 * @since 1.5 37 */ 38 public final class JCAUtil { 39 JCAUtil()40 private JCAUtil() { 41 // no instantiation 42 } 43 44 // size of the temporary arrays we use. Should fit into the CPU's 1st 45 // level cache and could be adjusted based on the platform 46 private final static int ARRAY_SIZE = 4096; 47 48 /** 49 * Get the size of a temporary buffer array to use in order to be 50 * cache efficient. totalSize indicates the total amount of data to 51 * be buffered. Used by the engineUpdate(ByteBuffer) methods. 52 */ getTempArraySize(int totalSize)53 public static int getTempArraySize(int totalSize) { 54 return Math.min(ARRAY_SIZE, totalSize); 55 } 56 57 // cached SecureRandom instance 58 private static class CachedSecureRandomHolder { 59 public static SecureRandom instance = new SecureRandom(); 60 } 61 62 /** 63 * Get a SecureRandom instance. This method should be used by JDK 64 * internal code in favor of calling "new SecureRandom()". That needs to 65 * iterate through the provider table to find the default SecureRandom 66 * implementation, which is fairly inefficient. 67 */ getSecureRandom()68 public static SecureRandom getSecureRandom() { 69 return CachedSecureRandomHolder.instance; 70 } 71 72 } 73