content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.kafka.connect.runtime.distributed;
  
  import java.security.NoSuchAlgorithmException;
  
  import javax.crypto.KeyGenerator;
  import javax.crypto.Mac;
  
  /**
   * An interface to allow the dependency injection of {@link Mac} and {@link KeyGenerator} instances for testing.
   * Implementations of this class should be thread-safe.
   */
  public interface Crypto {
  
      /**
       * Use the system implementation for cryptography calls.
       */
      Crypto SYSTEM = new SystemCrypto();
  
      /**
       * Returns a {@code Mac} object that implements the
       * specified MAC algorithm. See {@link Mac#getInstance(String)}.
       *
       * @param algorithm the standard name of the requested MAC algorithm.
       * @return the new {@code Mac} object
       * @throws NoSuchAlgorithmException if no {@code Provider} supports a
       *         {@code MacSpi} implementation for the specified algorithm
       */
      Mac mac(String algorithm) throws NoSuchAlgorithmException;
  
      /**
       * Returns a {@code KeyGenerator} object that generates secret keys
       * for the specified algorithm. See {@link KeyGenerator#getInstance(String)}.
       *
       * @param algorithm the standard name of the requested key algorithm.
       * @return the new {@code KeyGenerator} object
       * @throws NoSuchAlgorithmException if no {@code Provider} supports a
       *         {@code KeyGeneratorSpi} implementation for the
       *         specified algorithm
       */
      KeyGenerator keyGenerator(String algorithm) throws NoSuchAlgorithmException;
  
      class SystemCrypto implements Crypto {
          @Override
          public Mac mac(String algorithm) throws NoSuchAlgorithmException {
              return Mac.getInstance(algorithm);
          }
  
          @Override
          public KeyGenerator keyGenerator(String algorithm) throws NoSuchAlgorithmException {
              return KeyGenerator.getInstance(algorithm);
          }
      }
  
  }
  