OnJava8-Examples/onjava/Sets.java at master · BruceEckel/OnJava8-Examples · GitHub

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// onjava/Sets.java

// We make no guarantees that this code is fit for any purpose.

// Visit http://OnJava8.com for more book information.

package onjava;

import java.util.*;

public class Sets {

public static <T> Set<T> union(Set<T> a, Set<T> b) {

Set<T> result = new HashSet<>(a);

result.addAll(b);

return result;

}

public static <T>

Set<T> intersection(Set<T> a, Set<T> b) {

Set<T> result = new HashSet<>(a);

result.retainAll(b);

return result;

}

// Subtract subset from superset:

public static <T> Set<T>

difference(Set<T> superset, Set<T> subset) {

Set<T> result = new HashSet<>(superset);

result.removeAll(subset);

return result;

}

// Reflexive--everything not in the intersection:

public static

<T> Set<T> complement(Set<T> a, Set<T> b) {

return difference(union(a, b), intersection(a, b));

}

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