// Copyright 2012 Google Inc. All Rights Reserved.
//
// 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.google.collide.mvp;

import com.google.collide.shared.util.ListenerRegistrar;

/**
 * A component which can be explicitly shown and hidden. Implementors of this
 * interface must callback listeners for at least {@link ShowState#SHOWN} and
 * {@link ShowState#HIDDEN}.
 */
public interface ShowableComponent {

  /**
   * An indicating indicating the show state of a component.
   */
  public enum ShowState {
    SHOWING, SHOWN, HIDDEN, HIDING
  }

  /**
   * A listener which is notified of changes in the components
   * {@link ShowState}.
   */
  public interface ShowStateChangedListener {
    void onShowStateChanged(ShowState showState);
  }
  
  /**
   * Displays a component.
   */
  public void show();

  /**
   * Hides a component.
   */
  public void hide();

  /**
   * @return true if the state of the component is logically
   *         {@link ShowState#SHOWING} or {@link ShowState#SHOWN}.
   */
  public boolean isShowing();

  public ListenerRegistrar<ShowStateChangedListener> getShowStateChangedListenerRegistrar();
}
