/**
 * Copyright (c) 2011, University of Konstanz, Distributed Systems Group All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, are permitted
 * provided that the following conditions are met: * Redistributions of source code must retain the
 * above copyright notice, this list of conditions and the following disclaimer. * Redistributions
 * in binary form must reproduce the above copyright notice, this list of conditions and the
 * following disclaimer in the documentation and/or other materials provided with the distribution.
 * * Neither the name of the University of Konstanz nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package io.sirix.diff;

import io.sirix.exception.SirixException;
import org.checkerframework.checker.nullness.qual.NonNull;

/**
 * Observable class to fire diffs for interested observers, which implement the {@link DiffObserver}
 * interface.
 * 
 * @author Johannes Lichtenberger, University of Konstanz
 * 
 */
interface DiffObservable {
  /**
   * Fire a diff for exactly one node comparsion. Must call the diffListener(EDiff) method defined
   * in the {@link DiffObserver} interface.
   * 
   * @param diff the encountered diff
   * @param newNodeKey node key of current node in new revision
   * @param oldNodeKey node key of current node in old revision
   * @param depth current {@link DiffDepth} instance
   */
  void fireDiff(DiffFactory.DiffType diff, @NonNull long newNodeKey, @NonNull long oldNodeKey,
      @NonNull DiffDepth depth);

  /**
   * Diff computation done, thus inform listeners.
   * 
   * @throws SirixException if closing transactions failes
   */
  void done() throws SirixException;

  /**
   * Add an observer. This means add an instance of a class which implements the
   * {@link DiffObserver} interface.
   * 
   * @param observer instance of the class which implements {@link DiffObserver}
   */
  void addObserver(DiffObserver observer);

  /**
   * Remove an observer.
   * 
   * @param observer instance of the class which implements {@link DiffObserver}
   */
  void removeObserver(DiffObserver observer);
}
