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package org.opentripplanner.graph_builder.module.nearbystops;

import java.util.HashMap;

/**
 * A HashMap that has been extended to track the greatest or smallest value for each key. Note that
 * this does not change the meaning of the 'put' method. It adds two new methods that add the
 * min/max behavior. This class used to be inside SimpleIsochrone.
 */
class MinMap> extends HashMap {

  /**
   * Put the given key-value pair in the map if the map does not yet contain the key, or if the
   * value is less than the existing value for the same key.
   *
   * @return whether the key-value pair was inserted in the map.
   */
  boolean putMin(K key, V value) {
    V oldValue = this.get(key);
    if (oldValue == null || value.compareTo(oldValue) < 0) {
      this.put(key, value);
      return true;
    }
    return false;
  }

  /**
   * Put the given key-value pair in the map if the map does not yet contain the key, or if the
   * value is greater than the existing value for the same key.
   *
   * @return whether the key-value pair was inserted in the map.
   */
  boolean putMax(K key, V value) {
    V oldValue = this.get(key);
    if (oldValue == null || value.compareTo(oldValue) > 0) {
      this.put(key, value);
      return true;
    }
    return false;
  }
}