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029    
030    package edu.rice.cs.javalanglevels;
031    
032    /** Utility class, allows us to store two things as a single object. */
033    public class Pair<T,U> {
034      T _first;
035      U _second;
036    
037      public Pair(T first, U second) {
038        _first = first;
039        _second = second;
040      }
041    
042      public T getFirst() { return _first; }
043    
044      public U getSecond() { return _second; }
045      
046      public boolean equals(Object o) {
047        return  (o != null) && (o.getClass() == this.getClass()) &&
048          getFirst().equals(((Pair) o).getFirst()) && getSecond().equals(((Pair) o).getSecond());
049      }
050      
051      /** Define a hash code based on the first and second's hash code */
052      public int hashCode() { return _first.hashCode() ^ _second.hashCode(); }
053      
054      public String toString() { return "Pair(" + _first + ", " + _second + ")"; }
055    }