Ptidej-v5.2-master/POM Tests/data/ArgoUML_0.28/src/org/argouml/util/CollectionUtil.java
// $Id: CollectionUtil.java 10734 2006-06-11 15:43:58Z mvw $
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package org.argouml.util;

import java.util.Collection;
import java.util.List;

/**
 * Some helper methods for dealing with collections.
 *
 * @author Bob Tarling
 * @stereotype utility
 */
public final class CollectionUtil {

    /**
     * Can't construct a utility.
     */
    private CollectionUtil() {
    }

    /**
     * Return the first item from a collection using the most efficient
     * method possible.
     *
     * @param c The Collection.
     * @return the first element of a Collection.
     * @throws java.util.NoSuchElementException if the collection is empty.
     */
    public static Object getFirstItem(Collection c) {
        if (c instanceof List) {
            return ((List) c).get(0);
        }
        return c.iterator().next();
    }

    /**
     * Return the first item from a collection using the most efficient
     * method possible. Returns null for an empty collection.
     *
     * @param c The Collection.
     * @return the first element of a Collection.
     */
    public static Object getFirstItemOrNull(Collection c) {
        if (c.size() == 0) {
            return null;
        }
        return getFirstItem(c);
    }
}
