001/*
002 * nimbus-jose-jwt
003 *
004 * Copyright 2012-2016, Connect2id Ltd.
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use
007 * this file except in compliance with the License. You may obtain a copy of the
008 * License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software distributed
013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
015 * specific language governing permissions and limitations under the License.
016 */
017
018package com.nimbusds.jose.crypto.bc;
019
020
021import org.bouncycastle.jce.provider.BouncyCastleProvider;
022
023
024/**
025 * BouncyCastle JCA provider singleton, intended to prevent memory leaks by
026 * ensuring a single instance is loaded at all times. Application code that
027 * needs a BouncyCastle JCA provider should use the {@link #getInstance()}
028 * method to obtain an instance.
029 *
030 * <p>Requires the following optional dependency:
031 *
032 * <pre>
033 * &lt;dependency&gt;
034 *     &lt;groupId&gt;org.bouncycastle&lt;/groupId&gt;
035 *     &lt;artifactId&gt;bcprov-jdk15on&lt;/artifactId&gt;
036 *     &lt;version&gt;[1.68,2.0.0)&lt;/version&gt;
037 *     &lt;optional&gt;true&lt;/optional&gt;
038 * &lt;/dependency&gt;
039 * </pre>
040 *
041 * <p><strong>Important:</strong> The BouncyCastle FIPS JCA provider dependency
042 * must not be present to prevent class conflicts!
043 *
044 * @author Vladimir Dzhuvinov
045 */
046public final class BouncyCastleProviderSingleton {
047
048
049        /**
050         * The BouncyCastle provider, lazily instantiated.
051         */
052        private static BouncyCastleProvider bouncyCastleProvider;
053
054
055        /**
056         * Prevents external instantiation.
057         */
058        private BouncyCastleProviderSingleton() { }
059
060
061        /**
062         * Returns a BouncyCastle JCA provider instance.
063         *
064         * @return The BouncyCastle JCA provider instance.
065         */
066        public static BouncyCastleProvider getInstance() {
067                
068                if (bouncyCastleProvider == null) {
069                        bouncyCastleProvider = new BouncyCastleProvider();
070                }
071                return bouncyCastleProvider;
072        }
073}