/**
 * 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.model.adt;

import org.waveprotocol.wave.model.util.CopyOnWriteSet;

/**
 * Base class for {@linkplain ObservableBasicSet} implementations. Handles the
 * Observable aspect.
 *
 */
public abstract class AbstractObservableBasicSet<T> implements ObservableBasicSet<T> {

  /** All the listeners for changes to this map. */
  private final CopyOnWriteSet<Listener<? super T>> listeners = CopyOnWriteSet.create();

  /**
   * Initializes a new map with no listeners.
   */
  public AbstractObservableBasicSet() {
  }

  @Override
  public void addListener(Listener<T> listener) {
    listeners.add(listener);
  }

  @Override
  public void removeListener(Listener<T> listener) {
    listeners.remove(listener);
  }

  /** Fires the onValueAdded method for all listeners. */
  protected void fireOnValueAdded(T value) {
    for (Listener<? super T> listener : listeners) {
      listener.onValueAdded(value);
    }
  }

  /** Fires the onValueRemoved method for all listeners. */
  protected void fireOnValueRemoved(T value) {
    for (Listener<? super T> listener : listeners) {
      listener.onValueRemoved(value);
    }
  }
}