Java Collection Compare compare(final Collection o1, final Collection o2)

Description

compare

License

LGPL

Declaration

public static int compare(final Collection o1, final Collection o2) 

Method Source Code

//package com.java2s;
//License from project: LGPL 

import java.util.Collection;

public class Main {
    /**//www. j av a 2  s .  c  o m
     * Compare 2 objects. NULL values are greater than not null.
     *
     * @param o1
     * @param o2
     * @return
     */
    public static int compare(final Object o1, final Object o2) {
        if (null != o1 && null != o2) {
            if (o1.getClass().isArray() && o2.getClass().isArray()) {
                return compare((Object[]) o1, (Object[]) o2);
            } else if (o1.getClass().equals(o2.getClass())) {
                return compareSameTypes(o1, o2);
            } else {
                if (o1 instanceof Number && o2 instanceof Number) {
                    return compareSameTypes(((Number) o1).doubleValue(), ((Number) o2).doubleValue());
                } else {
                    return compareSameTypes(o1.toString(), o2.toString());
                }
            }
        } else if (null == o1) {
            return 1;
        } else if (null == o2) {
            return -1;
        }
        if (o1.equals(o2)) {
            return 0;
        }
        return -1;
    }

    public static int compare(final Object[] o1, final Object[] o2) {
        if (o1.length != o2.length) {
            // different length
            return compare(o1.length, o2.length);
        } else {
            // compare items
            for (int i = 0; i < o1.length; i++) {
                final int res = compare(o1[i], o2[i]);
                if (res != 0) {
                    return res;
                }
            }
        }
        return 0;
    }

    public static int compare(final Collection o1, final Collection o2) {
        final Object[] a1 = o1.toArray(new Object[o1.size()]);
        final Object[] a2 = o2.toArray(new Object[o2.size()]);
        return compare(a1, a2);
    }

    public static boolean equals(final Object o1, final Object o2) {
        return compare(o1, o2) == 0;
    }

    public static boolean equals(final Number o1, final Number o2) {
        return compare(o1, o2) == 0;
    }

    private static int compareSameTypes(final Object o1, final Object o2) {
        if (o1 instanceof Long) {
            return ((Long) o1).compareTo((Long) o2);
        } else if (o1 instanceof Integer) {
            return ((Integer) o1).compareTo((Integer) o2);
        } else if (o1 instanceof Byte) {
            return ((Byte) o1).compareTo((Byte) o2);
        } else if (o1 instanceof Double) {
            return ((Double) o1).compareTo((Double) o2);
        } else if (o1 instanceof String) {
            return ((String) o1).compareTo((String) o2);
        }
        return -1;
    }
}

Related

1. compare(Collection c1, Collection c2)
2. compare(Collection a, Collection b)
3. compare(Collection a, Collection b)
4. compare(Collection lhs, Collection rhs)
5. compare(final Collection c0, final Collection c1, final Comparator c)
6. compareAnyOrder(Collection c1, Collection c2)
7. compareCollections(Collection a, Collection b)
8. compareCollections(Collection cola, Collection colb)