daoadresseservice/util/NaturalOrderComparator.java

package dk.daoas.daoadresseservice.util;

import java.io.Serializable;

import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/*
NaturalOrderComparator.java -- Perform 'natural order' comparisons of strings in Java.
Copyright (C) 2003 by Pierre-Luc Paour <natorder@paour.com>

Based on the C version by Martin Pool, of which this is more or less a straight conversion.
Copyright (C) 2000 by Martin Pool <mbp@humbug.org.au>

This software is provided 'as-is', without any express or implied
warranty.  In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/


public class NaturalOrderComparator<T> implements Comparator<T>, Serializable
{
    int compareRight(String a, String b)
    {
        int bias = 0;
        int ia = 0;
        int ib = 0;

        // The longest run of digits wins. That aside, the greatest
        // value wins, but we can't know that it will until we've scanned
        // both numbers to know that they have the same magnitude, so we
        // remember it in BIAS.
        for (;; ia++, ib++)
        {
            char ca = charAt(a, ia);
            char cb = charAt(b, ib);

            if (!Character.isDigit(ca) && !Character.isDigit(cb))
            {
                return bias;
            }
            else if (!Character.isDigit(ca))
            {
                return -1;
            }
            else if (!Character.isDigit(cb))
            {
                return +1;
            }
            else if (ca < cb)
            {
                if (bias == 0)
                {
                    bias = -1;
                }
            }
            else if (ca > cb)
            {
                if (bias == 0)
                    bias = +1;
            }
            else if (ca == 0 && cb == 0)
            {
                return bias;
            }
        }
    }

    public int compare(T o1, T o2)
    {
        String a = o1.toString();
        String b = o2.toString();

        int ia = 0, ib = 0;
        int nza = 0, nzb = 0;
        char ca, cb;
        int result;

        while (true)
        {
            // only count the number of zeroes leading the last number compared
            nza = nzb = 0;

            ca = charAt(a, ia);
            cb = charAt(b, ib);

            // skip over leading spaces or zeros
            while (Character.isSpaceChar(ca) || ca == '0')
            {
                if (ca == '0')
                {
                    nza++;
                }
                else
                {
                    // only count consecutive zeroes
                    nza = 0;
                }

                ca = charAt(a, ++ia);
            }

            while (Character.isSpaceChar(cb) || cb == '0')
            {
                if (cb == '0')
                {
                    nzb++;
                }
                else
                {
                    // only count consecutive zeroes
                    nzb = 0;
                }

                cb = charAt(b, ++ib);
            }

            // process run of digits
            if (Character.isDigit(ca) && Character.isDigit(cb))
            {
                if ((result = compareRight(a.substring(ia), b.substring(ib))) != 0)
                {
                    return result;
                }
            }

            if (ca == 0 && cb == 0)
            {
                // The strings compare the same. Perhaps the caller
                // will want to call strcmp to break the tie.
                return nza - nzb;
            }

            if (ca < cb)
            {
                return -1;
            }
            else if (ca > cb)
            {
                return +1;
            }

            ++ia;
            ++ib;
        }
    }

    static char charAt(String s, int i)
    {
        if (i >= s.length())
        {
            return 0;
        }
        else
        {
            return s.charAt(i);
        }
    }

    public static void main(String[] args)
    {
        String[] strings = new String[] { "1-2", "1-02", "1-20", "10-20", "fred", "jane", "pic01",
            "pic2", "pic02", "pic02a", "pic3", "pic4", "pic 4 else", "pic 5", "pic05", "pic 5",
            "pic 5 something", "pic 6", "pic   7", "pic100", "pic100a", "pic120", "pic121",
            "pic02000", "tom", "x2-g8", "x2-y7", "x2-y08", "x8-y8" };

        List orig = Arrays.asList(strings);

        System.out.println("Original: " + orig);

        List scrambled = Arrays.asList(strings);
        Collections.shuffle(scrambled);

        System.out.println("Scrambled: " + scrambled);

        Collections.sort(scrambled, new NaturalOrderComparator());

        System.out.println("Sorted: " + scrambled);
    }
}
1	package dk.daoas.daoadresseservice.util;
2
3	import java.io.Serializable;
4
5	import java.util.Arrays;
6	import java.util.Collections;
7	import java.util.Comparator;
8	import java.util.List;
9
10	/*
11	NaturalOrderComparator.java -- Perform 'natural order' comparisons of strings in Java.
12	Copyright (C) 2003 by Pierre-Luc Paour <natorder@paour.com>
13
14	Based on the C version by Martin Pool, of which this is more or less a straight conversion.
15	Copyright (C) 2000 by Martin Pool <mbp@humbug.org.au>
16
17	This software is provided 'as-is', without any express or implied
18	warranty. In no event will the authors be held liable for any damages
19	arising from the use of this software.
20
21	Permission is granted to anyone to use this software for any purpose,
22	including commercial applications, and to alter it and redistribute it
23	freely, subject to the following restrictions:
24
25	1. The origin of this software must not be misrepresented; you must not
26	claim that you wrote the original software. If you use this software
27	in a product, an acknowledgment in the product documentation would be
28	appreciated but is not required.
29	2. Altered source versions must be plainly marked as such, and must not be
30	misrepresented as being the original software.
31	3. This notice may not be removed or altered from any source distribution.
32	*/
33
34
35
36	public class NaturalOrderComparator<T> implements Comparator<T>, Serializable
37	{
38	int compareRight(String a, String b)
39	{
40	int bias = 0;
41	int ia = 0;
42	int ib = 0;
43
44	// The longest run of digits wins. That aside, the greatest
45	// value wins, but we can't know that it will until we've scanned
46	// both numbers to know that they have the same magnitude, so we
47	// remember it in BIAS.
48	for (;; ia++, ib++)
49	{
50	char ca = charAt(a, ia);
51	char cb = charAt(b, ib);
52
53	if (!Character.isDigit(ca) && !Character.isDigit(cb))
54	{
55	return bias;
56	}
57	else if (!Character.isDigit(ca))
58	{
59	return -1;
60	}
61	else if (!Character.isDigit(cb))
62	{
63	return +1;
64	}
65	else if (ca < cb)
66	{
67	if (bias == 0)
68	{
69	bias = -1;
70	}
71	}
72	else if (ca > cb)
73	{
74	if (bias == 0)
75	bias = +1;
76	}
77	else if (ca == 0 && cb == 0)
78	{
79	return bias;
80	}
81	}
82	}
83
84	public int compare(T o1, T o2)
85	{
86	String a = o1.toString();
87	String b = o2.toString();
88
89	int ia = 0, ib = 0;
90	int nza = 0, nzb = 0;
91	char ca, cb;
92	int result;
93
94	while (true)
95	{
96	// only count the number of zeroes leading the last number compared
97	nza = nzb = 0;
98
99	ca = charAt(a, ia);
100	cb = charAt(b, ib);
101
102	// skip over leading spaces or zeros
103	while (Character.isSpaceChar(ca) \|\| ca == '0')
104	{
105	if (ca == '0')
106	{
107	nza++;
108	}
109	else
110	{
111	// only count consecutive zeroes
112	nza = 0;
113	}
114
115	ca = charAt(a, ++ia);
116	}
117
118	while (Character.isSpaceChar(cb) \|\| cb == '0')
119	{
120	if (cb == '0')
121	{
122	nzb++;
123	}
124	else
125	{
126	// only count consecutive zeroes
127	nzb = 0;
128	}
129
130	cb = charAt(b, ++ib);
131	}
132
133	// process run of digits
134	if (Character.isDigit(ca) && Character.isDigit(cb))
135	{
136	if ((result = compareRight(a.substring(ia), b.substring(ib))) != 0)
137	{
138	return result;
139	}
140	}
141
142	if (ca == 0 && cb == 0)
143	{
144	// The strings compare the same. Perhaps the caller
145	// will want to call strcmp to break the tie.
146	return nza - nzb;
147	}
148
149	if (ca < cb)
150	{
151	return -1;
152	}
153	else if (ca > cb)
154	{
155	return +1;
156	}
157
158	++ia;
159	++ib;
160	}
161	}
162
163	static char charAt(String s, int i)
164	{
165	if (i >= s.length())
166	{
167	return 0;
168	}
169	else
170	{
171	return s.charAt(i);
172	}
173	}
174
175	public static void main(String[] args)
176	{
177	String[] strings = new String[] { "1-2", "1-02", "1-20", "10-20", "fred", "jane", "pic01",
178	"pic2", "pic02", "pic02a", "pic3", "pic4", "pic 4 else", "pic 5", "pic05", "pic 5",
179	"pic 5 something", "pic 6", "pic 7", "pic100", "pic100a", "pic120", "pic121",
180	"pic02000", "tom", "x2-g8", "x2-y7", "x2-y08", "x8-y8" };
181
182	List orig = Arrays.asList(strings);
183
184	System.out.println("Original: " + orig);
185
186	List scrambled = Arrays.asList(strings);
187	Collections.shuffle(scrambled);
188
189	System.out.println("Scrambled: " + scrambled);
190
191	Collections.sort(scrambled, new NaturalOrderComparator());
192
193	System.out.println("Sorted: " + scrambled);
194	}
195	}