Scorer.java

// Copyright 2016 Twitter. 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.twitter.heron.packing.builder;

import com.twitter.heron.classification.InterfaceAudience;
import com.twitter.heron.classification.InterfaceStability;

/**
 * Scores an  object based on some heuristic. The ordering of the object by score could be used to
 * drive algorithms that rely on preference of objects (e.g. containers) to be used for packing
 * operations.
 */
@InterfaceAudience.LimitedPrivate
@InterfaceStability.Unstable
public interface Scorer<T> {

  /**
   * Whether or not scores produced by this scorer should sort ascending or descending
   * @return true if the low scores should sort before higher scores
   */
  boolean sortAscending();

  /**
   * Return the score for a given component on a container
   *
   * @param object the object to be scored
   * @return score for container
   */
  double getScore(T object);

}