src/main/org/apache/tools/ant/util/CollectionUtils.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
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 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.tools.ant.util;

import java.util.Dictionary;
import java.util.Enumeration;
import java.util.Vector;

/**
 * A set of helper methods related to collection manipulation.
 *
 * @author <a href="mailto:stefan.bodewig@epost.de">Stefan Bodewig</a>
 *
 * @since Ant 1.5
 */
public class CollectionUtils {

    /**
     * Vector.equals() doesn't do any good in 1.1
     *
     * @since Ant 1.5
     */
    public static boolean equals(Vector v1, Vector v2) {
        if (v1 == v2) {
            return true;
        }
        
        if (v1 == null || v2 == null) {
            return false;
        }

        if (v1.size() != v2.size()) {
            return false;
        }

        Enumeration e1 = v1.elements();
        Enumeration e2 = v2.elements();
        while (e1.hasMoreElements()) {
            if (!e1.nextElement().equals(e2.nextElement())) {
                return false;
            }
        }
        
        // don't need to check e2.hasMoreElements as the Vectors have
        // same size.

        return true;
    }

    /**
     * Hashtable.equals() doesn't do any good in 1.1
     *
     * <p>Follows the equals contract of Java 2's Map.</p>
     *
     * @since Ant 1.5
     */
    public static boolean equals(Dictionary d1, Dictionary d2) {
        if (d1 == d2) {
            return true;
        }
        
        if (d1 == null || d2 == null) {
            return false;
        }

        if (d1.size() != d2.size()) {
            return false;
        }

        Enumeration e1 = d1.keys();
        while (e1.hasMoreElements()) {
            Object key = e1.nextElement();
            Object value1 = d1.get(key);
            Object value2 = d2.get(key);
            if (value2 == null || !value1.equals(value2)) {
                return false;
            }
        }
        
        // don't need the opposite check as the Dictionaries have the
        // same size, so we've also covered all keys of d2 already.

        return true;
    }
}