//
// File:        SkipListElement.java
//
// Language:    Java 1.02
// Description: Class for a single node in a "SkipList" 
//              as proposed by William Pugh
//
//              To get faster data access to the nodes, you have to direct 
//              access data.
//
// Author:  Thomas Wenger, Jan-7-1998
//

public class SkipListElement {
  
  ///////////////////////////////////////////////////////////////////////////
  // Constructor:
  //   Constructs a new element of a skip list.
  //   level, key and value of the new node are given 
  //   
  public SkipListElement(int level, int key, int value) {
    this.key = key;
    this.value = value;
    forward = new SkipListElement[level+1];
  }
  
  
  ///////////////////////////////////////////////////////////////////////////
  // toString() overwrites java.lang.Object.toString()
  //   composes a multiline-string describing this node:
  //
  public String toString() {
    String result = "";
    
    // element data: 
    result += " k:" + key + ", v:" + value + ", l:" + getLevel() + ". fwd k: ";
    
    // key of forward pointed nodes:
    for (int i=0; i<=getLevel(); i++) {
      if (forward[i]!=null) {
        result += i + ": " + forward[i].key + ", ";
      }
      else {
        result += i + ": nil, ";
      }
    }

    return result;
  }
  
  
  ///////////////////////////////////////////////////////////////////////////
  // getLevel():
  //   returns the level of this node (count starting at 0)
  //
  int getLevel() { 
    return forward.length-1;
  }
    
  
  ///////////////////////////////////////////////////////////////////////////
  // accessible data members:
  //   access is "friendly", this way all classes in this package can access
  //   the data member directly: performance is increased
  int key;                        // key data (sort and search criterion)
  int value;                      // associated value
  SkipListElement forward[];      // array of forward pointers
  
}