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1   package net.sf.josceleton.commons.util;
2   
3   import java.util.Arrays;
4   import java.util.Collections;
5   import java.util.HashSet;
6   import java.util.Set;
7   
8   /**
9    * @since 0.
10   */
11  public final class CollectionUtil {
12  
13  	private CollectionUtil() {
14  		// utility class is not instantiable
15  	}
16  	
17  	public static <T> Set<T> toUnmodifiableSet(final T... items) {
18  		if(items.length == 0) {
19  			return Collections.emptySet();
20  		}
21  		return Collections.unmodifiableSet(new HashSet<T>(Arrays.asList(items)));
22  	}
23  
24  	public static <T> Set<T> mergeToUnmodifiableSet(final T item, final T[] optionallyMoreItems) {
25  		final Set<T> set = new HashSet<T>(1 + optionallyMoreItems.length);
26  		
27  		set.add(item);
28  		for (final T optionally : optionallyMoreItems) {
29  			set.add(optionally);
30  		}
31  		
32  		return Collections.unmodifiableSet(set);
33  	}
34  
35  }