content: /**
   * 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.apache.aurora.scheduler.updater.strategy;
  
  import java.util.Set;
  
  import com.google.common.collect.ImmutableSet;
  import com.google.common.collect.Ordering;
  
  /**
   * An update strategy that will only add more work when the current active group is empty.
   *
   * @param <T> Instance type.
   */
  public class BatchStrategy<T extends Comparable<T>> extends ActiveLimitedStrategy<T> {
  
    /**
     * Creates a batch strategy that will allow a limited number of active entries.
     *
     * @param maxActive The maximum number of active entries.
     */
    public BatchStrategy(Ordering<T> ordering, int maxActive) {
      super(ordering, maxActive);
    }
  
    @Override
    Set<T> doGetNextGroup(Set<T> idle, Set<T> active) {
      return active.isEmpty() ? idle : ImmutableSet.of();
    }
  }
  