/**
 * Copyright 2010 Google Inc.
 *
 * 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 org.waveprotocol.wave.client.widget.button;

/**
 * Simplified (compared to the GWT version) listener interface for mouse events -
 * this interface doesn't depend on GWT.
 *
 */
public interface MouseListener {
  /**
   * A {@link MouseListener} that does nothing when it receives events.
   */
  public static final MouseListener NO_OP = new MouseListener() {
    @Override
    public void onMouseUp() { }

    @Override
    public void onMouseLeave() { }

    @Override
    public void onMouseEnter() { }

    @Override
    public void onMouseDown() { }

    @Override
    public void onClick() { }
  };

  /**
   * Called when the mouse is pressed over some widget.
   */
  void onMouseDown();

  /**
   * Called when the mouse enters some widget.
   */
  void onMouseEnter();

  /**
   * Called when the mouse leaves some widget.
   */
  void onMouseLeave();

  /**
   * Called when the mouse is released over some widget.
   */
  void onMouseUp();

  /**
   * Called when the mouse is clicked.
   */
  void onClick();
}