Utils.java Source code

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Here is the source code for Utils.java

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/*
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 *
 * Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common
 * Development and Distribution License("CDDL") (collectively, the
 * "License"). You may not use this file except in compliance with the
 * License. You can obtain a copy of the License at
 * http://www.netbeans.org/cddl-gplv2.html
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 */

import java.util.Enumeration;
import java.util.Iterator;

/**
 * @since 4.37
 * @author Jaroslav Tulach
 */

public class Utils {
    /**
     * Treat an {@link Enumeration} as an {@link Iterable} so it can be used in an enhanced for-loop.
     * Bear in mind that the enumeration is "consumed" by the loop and so should be used only once.
     * Generally it is best to put the code which obtains the enumeration inside the loop header.
     * <div class="nonnormative">
     * <p>Example of correct usage:</p>
     * <pre>
     * ClassLoader loader = ...;
     * String name = ...;
     * for (URL resource : NbCollections.iterable(loader.{@link ClassLoader#getResources getResources}(name))) {
     *     // ...
     * }
     * </pre>
     * </div>
     * @param enumeration an enumeration
     * @return an iterable wrapper which will traverse the enumeration once
     *         ({@link Iterator#remove} is not supported)
     * @throws NullPointerException if the enumeration is null
     * @see <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6349852">Java bug #6349852</a>
     * @since org.openide.util 7.5
     */
    public static <E> Iterable<E> iterable(final Enumeration<E> enumeration) {
        if (enumeration == null) {
            throw new NullPointerException();
        }
        return new Iterable<E>() {
            public Iterator<E> iterator() {
                return new Iterator<E>() {
                    public boolean hasNext() {
                        return enumeration.hasMoreElements();
                    }

                    public E next() {
                        return enumeration.nextElement();
                    }

                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

}