Set operations : Set « Collections Data Structure « Java

1. Java
2. Collections Data Structure
3. Set

Set operations

      


import java.util.LinkedHashSet;
import java.util.Set;

/**
 * Note: This code is based on -<br>
 * http://java.sun.com/docs/books/tutorial/collections/interfaces/set.html<br>
 * 
 * Using LinkedHashSet, even though slightly slower than HashSet, in order to
 * ensure order is always respected (i.e. if called with TreeSet or
 * LinkedHashSet implementations).
 * 
 * @author Ravi Mohan
 * @author Ciaran O'Reilly
 */
public class SetOps {

  /**
   * 
   * @param <T>
   * @param s1
   * @param s2
   * @return the union of s1 and s2. (The union of two sets is the set
   *         containing all of the elements contained in either set.)
   */
  public static <T> Set<T> union(Set<T> s1, Set<T> s2) {
    Set<T> union = new LinkedHashSet<T>(s1);
    union.addAll(s2);
    return union;
  }

  /**
   * 
   * @param <T>
   * @param s1
   * @param s2
   * @return the intersection of s1 and s2. (The intersection of two sets is
   *         the set containing only the elements common to both sets.)
   */
  public static <T> Set<T> intersection(Set<T> s1, Set<T> s2) {
    Set<T> intersection = new LinkedHashSet<T>(s1);
    intersection.retainAll(s2);
    return intersection;
  }

  /**
   * 
   * @param <T>
   * @param s1
   * @param s2
   * @return the (asymmetric) set difference of s1 and s2. (For example, the
   *         set difference of s1 minus s2 is the set containing all of the
   *         elements found in s1 but not in s2.)
   */
  public static <T> Set<T> difference(Set<T> s1, Set<T> s2) {
    Set<T> difference = new LinkedHashSet<T>(s1);
    difference.removeAll(s2);
    return difference;
  }
}

   
    
    
    
    
    
  

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