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/*
 * All content copyright Terracotta, Inc., unless otherwise indicated.
 *
 * 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.terracotta.statistics;

import org.terracotta.statistics.observer.ChainedObserver;

/**
 * Source statistic implementations support derived statistics.
 * 
 * Derived statistics can be registered and will then receive the relevant
 * observer calls to update their status.
 * 
 * @param  Supported derived observer type
 */
public interface SourceStatistic {
  
  /**
   * Register the given {@code Observer} to be called by this {@code SourceStatistic}
   * 
   * @param derived statistic to be registered
   */
  void addDerivedStatistic(T derived);
  
  /**
   * Remove the given registered {@Observer} from this {@code SourceStatistic}.
   * 
   * @param derived statistic to be removed
   */
  void removeDerivedStatistic(T derived);
}