JavaAlgorithms/DataStructures/Heaps/HeapElement.java

package DataStructures.Heaps;

/**
 * Class for heap elements.<br>
 *
 * <p>A heap element contains two attributes: a key which will be used to build the tree (int or
 * double, either primitive type or object) and any kind of IMMUTABLE object the user sees fit to
 * carry any information he/she likes. Be aware that the use of a mutable object might jeopardize
 * the integrity of this information.
 *
 * @author Nicolas Renard
 */
public class HeapElement {
  private final double key;
  private final Object additionalInfo;

  // Constructors

  /**
   * @param key : a number of primitive type 'double'
   * @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
   *     additional information of use for the user
   */
  public HeapElement(double key, Object info) {
    this.key = key;
    this.additionalInfo = info;
  }

  /**
   * @param key : a number of primitive type 'int'
   * @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
   *     additional information of use for the user
   */
  public HeapElement(int key, Object info) {
    this.key = key;
    this.additionalInfo = info;
  }

  /**
   * @param key : a number of object type 'Integer'
   * @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
   *     additional information of use for the user
   */
  public HeapElement(Integer key, Object info) {
    this.key = key;
    this.additionalInfo = info;
  }

  /**
   * @param key : a number of object type 'Double'
   * @param info : any kind of IMMUTABLE object. May be null, since the purpose is only to carry
   *     additional information of use for the user
   */
  public HeapElement(Double key, Object info) {
    this.key = key;
    this.additionalInfo = info;
  }

  /** @param key : a number of primitive type 'double' */
  public HeapElement(double key) {
    this.key = key;
    this.additionalInfo = null;
  }

  /** @param key : a number of primitive type 'int' */
  public HeapElement(int key) {
    this.key = key;
    this.additionalInfo = null;
  }

  /** @param key : a number of object type 'Integer' */
  public HeapElement(Integer key) {
    this.key = key;
    this.additionalInfo = null;
  }

  /** @param key : a number of object type 'Double' */
  public HeapElement(Double key) {
    this.key = key;
    this.additionalInfo = null;
  }

  // Getters

  /** @return the object containing the additional info provided by the user. */
  public Object getInfo() {
    return additionalInfo;
  }

  /** @return the key value of the element */
  public double getKey() {
    return key;
  }

  // Overridden object methods

  public String toString() {
    return "Key: " + key + " - " + additionalInfo.toString();
  }

  /**
   * @param otherHeapElement
   * @return true if the keys on both elements are identical and the additional info objects are
   *     identical.
   */
  @Override
  public boolean equals(Object o) {
    if (o != null) {
      if (!(o instanceof HeapElement)) return false;
      HeapElement otherHeapElement = (HeapElement) o;
      return (this.key == otherHeapElement.key)
          && (this.additionalInfo.equals(otherHeapElement.additionalInfo));
    }
    return false;
  }

  @Override
  public int hashCode() {
    int result = 0;
    result = 31 * result + (int) key;
    result = 31 * result + (additionalInfo != null ? additionalInfo.hashCode() : 0);
    return result;
  }
}