/**
 * Copyright (C) 2015-2017 Regents of the University of California.
 * @author: Jeff Thompson <jefft0@remap.ucla.edu>
 * @author: From ndn-group-encrypt src/consumer-db https://github.com/named-data/ndn-group-encrypt
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * A copy of the GNU Lesser General Public License is in the file COPYING.
 */

package net.named_data.jndn.encrypt;

import net.named_data.jndn.Name;
import net.named_data.jndn.util.Blob;

/**
 * ConsumerDb is an abstract base class the storage of decryption keys for the
 * consumer. A subclass must implement the methods. For example, see
 * Sqlite3ConsumerDb.
 * @note This class is an experimental feature. The API may change.
 */
public abstract class ConsumerDb {
  /**
   * ConsumerDb.Error extends Exception for errors using ConsumerDb methods.
   * Note that even though this is called "Error" to be consistent with the
   * other libraries, it extends the Java Exception class, not Error.
   */
  public static class Error extends Exception {
    public Error(String message)
    {
      super(message);
    }
  }

  /**
   * Get the key with keyName from the database.
   * @param keyName The key name.
   * @return A Blob with the encoded key, or an isNull Blob if cannot find the
   * key with keyName.
   * @throws ConsumerDb.Error for a database error.
   */
  public abstract Blob
  getKey(Name keyName) throws ConsumerDb.Error;

  /**
   * Add the key with keyName and keyBlob to the database.
   * @param keyName The key name.
   * @param keyBlob The encoded key.
   * @throws ConsumerDb.Error if a key with the same keyName already exists in
   * the database, or other database error.
   */
  public abstract void
  addKey(Name keyName, Blob keyBlob) throws ConsumerDb.Error;

  /**
   * Delete the key with keyName from the database. If there is no key with
   * keyName, do nothing.
   * @param keyName The key name.
   * @throws ConsumerDb.Error for a database error.
   */
  public abstract void
  deleteKey(Name keyName) throws ConsumerDb.Error;
}