org.jfree.util.ObjectUtils.java Source code

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Here is the source code for org.jfree.util.ObjectUtils.java

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/*
 * ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.
 * Project Info: http://www.jfree.org/jcommon/index.html
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 * ----------------
 * ObjectUtils.java
 * ----------------
 * (C) Copyright 2003, 2004, by Object Refinery Limited.
 * Original Author: David Gilbert (for Object Refinery Limited);
 * Contributor(s): -;
 * $Id: ObjectUtils.java,v 1.1 2011-01-31 09:01:41 klukas Exp $
 * Changes
 * -------
 * 25-Mar-2003 : Version 1 (DG);
 * 15-Sep-2003 : Fixed bug in clone(List) method (DG);
 */

package org.jfree.util;

import java.util.Iterator;
import java.util.List;

/**
 * A collection of useful static utility methods.
 */
public abstract class ObjectUtils {

    /**
     * Returns <code>true</code> if the two objects are equal OR both <code>null</code>.
     * 
     * @param o1
     *           object 1 (<code>null</code> permitted).
     * @param o2
     *           object 2 (<code>null</code> permitted).
     * @return <code>true</code> or <code>false</code>.
     */
    public static boolean equal(Object o1, Object o2) {

        if (o1 != null) {
            return o1.equals(o2);
        } else {
            return (o2 == null);
        }

    }

    /**
     * Returns a hash code for an object, or zero if the object is <code>null</code>.
     * 
     * @param object
     *           the object (<code>null</code> permitted).
     * @return The object's hash code (or zero if the object is <code>null</code>).
     */
    public static int hashCode(final Object object) {
        int result = 0;
        if (object != null) {
            result = object.hashCode();
        }
        return result;
    }

    /**
     * Returns a clone of the object, if the object implements the {@link PublicCloneable} interface, otherwise the original object reference is returned.
     * 
     * @param object
     *           the object to clone (<code>null</code> permitted).
     * @return A clone or the original object reference.
     * @throws CloneNotSupportedException
     *            if the object cannot be cloned.
     */
    public static Object clone(final Object object) throws CloneNotSupportedException {
        Object result = object;
        if (object != null) {
            if (object instanceof PublicCloneable) {
                final PublicCloneable pc = (PublicCloneable) object;
                result = pc.clone();
            }
        }
        return result;
    }

    /**
     * Returns a clone of the list. The objects within the list are cloned IF they implement
     * the {@link PublicCloneable} interface, otherwise the reference to the original object is
     * retained in the cloned list.
     * 
     * @param list
     *           the list.
     * @return A clone of the list.
     * @throws CloneNotSupportedException
     *            if the list could not be cloned.
     */
    public static List clone(final List list) throws CloneNotSupportedException {
        List result = null;
        if (list != null) {
            try {
                final List clone = (List) list.getClass().newInstance();
                final Iterator iterator = list.iterator();
                while (iterator.hasNext()) {
                    clone.add(ObjectUtils.clone(iterator.next()));
                }
                result = clone;
            } catch (Exception e) {
                throw new CloneNotSupportedException("ObjectUtils.clone(List) - Exception.");
            }
        }
        return result;
    }

    /**
     * Returns <code>true</code> if the two objects are equal OR both <code>null</code>.
     * 
     * @param o1
     *           object 1.
     * @param o2
     *           object 2.
     * @return <code>true</code> or <code>false</code>.
     * @deprecated Use ObjectUtils.equal(...).
     */
    public static boolean equalOrBothNull(final Object o1, final Object o2) {

        if (o1 != null) {
            return o1.equals(o2);
        } else {
            return (o2 == null);
        }

    }

}