assertThat(lru.get("aaa"), is("111"));
        Iterator<String> i = lru.keySet().iterator();
        assertThat(i.next(), is("bbb"));
        assertThat(i.next(), is("ccc"));
        assertThat(i.next(), is("aaa"));
        lru.put("ddd", "444");
        assertThat(lru.size(), is(3));
        assertThat(lru.get("bbb"), is(nullValue()));
        i = lru.keySet().iterator();
        assertThat(i.next(), is("ccc"));

    }

    @Override
    public Enumeration<Object> keys() {
        return getProperties().keys();
    }

    @Override
    public Set<Object> keySet() {
        return getProperties().keySet();
    }

    @Override
    public void list(final PrintStream out) {
        getProperties().list(out);
    }

    @Override
    public void list(final PrintWriter out) {

     */
    public CaseInsensitiveSet(final int initialCapacity) {
        map = new CaseInsensitiveMap<>(initialCapacity);
    }

    @Override
    public Iterator<String> iterator() {
        return map.keySet().iterator();
    }

    @Override
    public int size() {
        return map.size();
    }

    @Override
    public boolean isEmpty() {
        return map.isEmpty();
    }

    @Override

     *
     * @return an Iterator over the elements in this set.
     * @see ConcurrentModificationException
     */
    @Override
    public Iterator<E> iterator() {
        return map.keySet().iterator();
    }

    /**
     * Returns the number of elements in this set (its cardinality).
     *
     * @return the number of elements in this set (its cardinality).
     */
    @Override

        assertArgumentNotEmpty("methodName", methodName);

        return methodDescsCache.containsKey(methodName);
    }

    @Override
    public String[] getMethodNames() {
        return methodDescsCache.keySet().toArray(new String[methodDescsCache.size()]);
    }

    /**
     * {@link PropertyDesc}を返します。
     *
     * @param propertyName
     *            プロパティ名

 * import static org.codelibs.core.collection.MultiIterator.*;
 *
 * List<String> list = ...;
 * Set<String> set = ...;
 * Map<String, Object> map = ...;
 * for (String element : iterable(list, set, map.keySet())) {
 *     ...
 * }
 * </pre>
 *
 * @author koichik
 * @param <E>
 *            要素の型
 */
public class MultiIterator<E> implements Iterator<E> {

    /** {@link Iterator}の配列 */