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/*
 * Copyright (C) 2014-2023 Philip Helger (www.helger.com)
 * philip[at]helger[dot]com
 *
 * Licensed 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 com.helger.commons.state;

import javax.annotation.Nonnull;

/**
 * Very simple interface for an object that has changed/unchanged indication.
 *
 * @author Philip Helger
 */
public interface IChangeIndicator
{
  /**
   * @return true if changed and false if unchanged.
   */
  boolean isChanged ();

  /**
   * @return true if unchanged and false if changed.
   */
  default boolean isUnchanged ()
  {
    return !isChanged ();
  }

  @Nonnull
  default EChange or (@Nonnull final IChangeIndicator aChange)
  {
    return or (aChange.isChanged ());
  }

  @Nonnull
  default EChange or (final boolean bChange)
  {
    return EChange.valueOf (isChanged () || bChange);
  }

  @Nonnull
  default EChange and (@Nonnull final IChangeIndicator aChange)
  {
    return and (aChange.isChanged ());
  }

  @Nonnull
  default EChange and (final boolean bChange)
  {
    return EChange.valueOf (isChanged () && bChange);
  }
}