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 package org.apidesign.impl.security.spi;

 import java.nio.ByteBuffer;

 import org.apidesign.spi.security.Digestor;

 /**

  *

  * @author jarda

  */

 public abstract class DigestorAccessor {

     private static DigestorAccessor INSTANCE;

     protected DigestorAccessor() {

         assert INSTANCE == null;

         INSTANCE = this;

     }

     public static DigestorAccessor getDefault() {

         try {

             Class.forName(Digestor.class.getName(), true, DigestorAccessor.class.getClassLoader());

             return INSTANCE;

         } catch (ClassNotFoundException ex) {

             throw new IllegalStateException(ex);

         }

     }

     protected abstract <Data> byte[] digest(Digestor<Data> dig, Data data);

     protected abstract <Data> Data create(Digestor<Data> dig, String algorithm); 

     protected abstract <Data> void update(Digestor<Data> dig, Data data, ByteBuffer input);

 }