Showing the changes to java/pkg/sun/security/jca/JCAUtil.java (1 of 18352 files). Show all
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| 1 | +/* | |
| 2 | + * Copyright (c) 2003, 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 | + | |
| 40 | + private JCAUtil() { | |
| 41 | + // no instantiation | |
| 42 | + } | |
| 43 | + | |
| 44 | + // lock to use for synchronization | |
| 45 | + private static final Object LOCK = JCAUtil.class; | |
| 46 | + | |
| 47 | + // cached SecureRandom instance | |
| 48 | + private static volatile SecureRandom secureRandom; | |
| 49 | + | |
| 50 | + // size of the temporary arrays we use. Should fit into the CPU's 1st | |
| 51 | + // level cache and could be adjusted based on the platform | |
| 52 | + private final static int ARRAY_SIZE = 4096; | |
| 53 | + | |
| 54 | + /** | |
| 55 | + * Get the size of a temporary buffer array to use in order to be | |
| 56 | + * cache efficient. totalSize indicates the total amount of data to | |
| 57 | + * be buffered. Used by the engineUpdate(ByteBuffer) methods. | |
| 58 | + */ | |
| 59 | + public static int getTempArraySize(int totalSize) { | |
| 60 | + return Math.min(ARRAY_SIZE, totalSize); | |
| 61 | + } | |
| 62 | + | |
| 63 | + /** | |
| 64 | + * Get a SecureRandom instance. This method should me used by JDK | |
| 65 | + * internal code in favor of calling "new SecureRandom()". That needs to | |
| 66 | + * iterate through the provider table to find the default SecureRandom | |
| 67 | + * implementation, which is fairly inefficient. | |
| 68 | + */ | |
| 69 | + public static SecureRandom getSecureRandom() { | |
| 70 | + // we use double checked locking to minimize synchronization | |
| 71 | + // works because we use a volatile reference | |
| 72 | + SecureRandom r = secureRandom; | |
| 73 | + if (r == null) { | |
| 74 | + synchronized (LOCK) { | |
| 75 | + r = secureRandom; | |
| 76 | + if (r == null) { | |
| 77 | + r = new SecureRandom(); | |
| 78 | + secureRandom = r; | |
| 79 | + } | |
| 80 | + } | |
| 81 | + } | |
| 82 | + return r; | |
| 83 | + } | |
| 84 | + | |
| 85 | +} | |