SetOps.java Source code

Introduction

Here is the source code for SetOps.java

Source

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;
    }
}