BouncyCastleProviderSingleton.java

/*
 * nimbus-jose-jwt
 *
 * Copyright 2012-2016, Connect2id Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use
 * this file except in compliance with the License. You may obtain a copy of the
 * License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed
 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */

package com.nimbusds.jose.crypto.bc;


import org.bouncycastle.jce.provider.BouncyCastleProvider;


/**
 * BouncyCastle JCA provider singleton, intended to prevent memory leaks by
 * ensuring a single instance is loaded at all times. Application code that
 * needs a BouncyCastle JCA provider should use the {@link #getInstance()}
 * method to obtain an instance.
 *
 * <p>Requires the following optional dependency:
 *
 * <pre>
 * &lt;dependency&gt;
 *     &lt;groupId&gt;org.bouncycastle&lt;/groupId&gt;
 *     &lt;artifactId&gt;bcprov-jdk15on&lt;/artifactId&gt;
 *     &lt;version&gt;[1.68,2.0.0)&lt;/version&gt;
 *     &lt;optional&gt;true&lt;/optional&gt;
 * &lt;/dependency&gt;
 * </pre>
 *
 * <p><strong>Important:</strong> The BouncyCastle FIPS JCA provider dependency
 * must not be present to prevent class conflicts!
 *
 * @author Vladimir Dzhuvinov
 */
public final class BouncyCastleProviderSingleton {


	/**
	 * The BouncyCastle provider, lazily instantiated.
	 */
	private static BouncyCastleProvider bouncyCastleProvider;


	/**
	 * Prevents external instantiation.
	 */
	private BouncyCastleProviderSingleton() { }


	/**
	 * Returns a BouncyCastle JCA provider instance.
	 *
	 * @return The BouncyCastle JCA provider instance.
	 */
	public static BouncyCastleProvider getInstance() {
		
		if (bouncyCastleProvider == null) {
			bouncyCastleProvider = new BouncyCastleProvider();
		}
		return bouncyCastleProvider;
	}
}