daoadresseservice/util/NaturalOrderComparator.java

package dk.daoas.daoadresseservice.util;

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