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/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2008-2013 jOpenDocument, by ILM Informatique. All rights reserved.
 * 
 * The contents of this file are subject to the terms of the GNU
 * General Public License Version 3 only ("GPL").  
 * You may not use this file except in compliance with the License. 
 * You can obtain a copy of the License at http://www.gnu.org/licenses/gpl-3.0.html
 * See the License for the specific language governing permissions and limitations under the License.
 * 
 * When distributing the software, include this License Header Notice in each file.
 * 
 */

/*
 * Créé le 14 avr. 2005
 */
package org.jopendocument.util;

import org.jopendocument.util.cc.ITransformer;

import java.math.BigDecimal;
import java.util.Comparator;
import java.util.List;

/**
 * @author Sylvain CUAZ
 */
public class CompareUtils {

    /**
     * Compare 2 nombres entier avec longValue().
     * 
     * @param n1 le premier nombre.
     * @param n2 le deuxième nombre.
     * @return 0 si ==, >0 si n1>2.
     */
    public static final int compareIntNumbers(Number n1, Number n2) {
        return compareLong(n1.longValue(), n2.longValue());
    }

    static public final int compareInt(int int1, int int2) {
        if (int1 < int2)
            return -1;
        else if (int1 == int2)
            return 0;
        else
            return +1;
    }

    static public final int compareLong(long int1, long int2) {
        if (int1 < int2)
            return -1;
        else if (int1 == int2)
            return 0;
        else
            return +1;
    }

    /**
     * Compare two objects if they're numbers or comparable.
     * 
     * @param o1 first object.
     * @param o2 second object.
     * @return a negative integer, zero, or a positive integer as o1 is less than, equal to, or
     *         greater than o2.
     * @throws ClassCastException if o1 is neither a {@link Number} nor a {@link Comparable}, or if
     *         o2's type prevents it from being compared to o1.
     * @throws NullPointerException if o1 or o2 is null.
     * @see Comparable#compareTo(Object)
     * @see NumberUtils#compare(Number, Number)
     */
    static public final int compare(final Object o1, final Object o2) throws ClassCastException {
        if (o1 == null || o2 == null)
            throw new NullPointerException();
        if (o1 instanceof Number && o2 instanceof Number) {
            return NumberUtils.compare((Number) o1, (Number) o2);
        } else {
            // see Arrays.mergeSort()
            @SuppressWarnings({ "rawtypes", "unchecked" })
            final int res = ((Comparable) o1).compareTo(o2);
            return res;
        }
    }

    /**
     * Renvoie un comparateur qui utilise successivement la liste passée tant que les objets sont
     * égaux.
     * 
     * @param comparators une liste de Comparator.
     * @return le Comparator demandé.
     * @param  type of comparator
     */
    static public final  Comparator createComparator(final List> comparators) {
        return new Comparator() {
            public String toString() {
                return "CompareUtils comparator with " + comparators;
            }

            public int compare(T o1, T o2) {
                int result = 0;
                int i = 0;
                while (i < comparators.size() && result == 0) {
                    final Comparator transf = comparators.get(i);
                    result = transf.compare(o1, o2);
                    i++;
                }
                return result;
            }
        };
    }

    /**
     * Compare 2 objets pouvant être null.
     * 
     * @param o1 the first object, can be null.
     * @param o2 the second object, can be null.
     * @return true if both are null or if o1.equals(o2).
     * @see Object#equals(Object)
     */
    static public final boolean equals(Object o1, Object o2) {
        if (o1 == null && o2 == null)
            return true;
        if (o1 == null || o2 == null)
            return false;
        return o1.equals(o2);
    }

    /**
     * Compare 2 objets pouvant être null avec compareTo(). Useful since for some
     * classes equals() is more specific than compareTo()==0, e.g. {@link BigDecimal#equals(Object)}
     * doesn't compare the numeric value but instance variables (1E2 is not equal to 100 or 100.00).
     * 
     * @param o1 the first object, can be null.
     * @param o2 the second object, can be null.
     * @return true if both are null or if o1.compareTo(o2) == 0.
     * @see Comparable#compareTo(Object)
     */
    static public final  boolean equalsWithCompareTo(Comparable o1, T o2) {
        if (o1 == null && o2 == null)
            return true;
        if (o1 == null || o2 == null)
            return false;
        return o1.compareTo(o2) == 0;
    }

    static public interface Equalizer {
        public boolean equals(T o1, T o2);
    }

    static public final Equalizer