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
   * <p>
   * http://www.apache.org/licenses/LICENSE-2.0
   * <p>
   * 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.atlas.utils;
  
  import java.security.MessageDigest;
  import java.security.NoSuchAlgorithmException;
  
  public class SHA256Utils {
      private static final ThreadLocal<MessageDigest> DIGESTER_FACTORY = ThreadLocal.withInitial(() -> {
          try {
              return MessageDigest.getInstance("SHA-256");
          } catch (NoSuchAlgorithmException e) {
              throw new RuntimeException(e);
          }
      });
  
      private SHA256Utils() {
          // to block instanations
      }
  
      /**
       * Create a thread local SHA256 digester.
       */
  
      public static MessageDigest getDigester() {
          MessageDigest digester = DIGESTER_FACTORY.get();
  
          digester.reset();
  
          return digester;
      }
  
      public static String toString(byte[] hash) {
          try {
              StringBuilder hexString = new StringBuilder();
  
              for (int i = 0; i < hash.length; i++) {
                  String hex = Integer.toHexString(0xff & hash[i]);
  
                  if (hex.length() == 1) {
                      hexString.append('0');
                  }
  
                  hexString.append(hex);
              }
  
              return hexString.toString();
          } catch (Exception ex) {
              throw new RuntimeException(ex);
          }
      }
  }
  