1
|
/**
|
2
|
* '$RCSfile$'
|
3
|
* Purpose: A Class that sorts two NodeRecords
|
4
|
* Copyright: 2000 Regents of the University of California and the
|
5
|
* National Center for Ecological Analysis and Synthesis
|
6
|
* Authors: Matt Jones
|
7
|
* Release: @release@
|
8
|
*
|
9
|
* '$Author: jones $'
|
10
|
* '$Date: 2000-09-01 17:14:22 -0700 (Fri, 01 Sep 2000) $'
|
11
|
* '$Revision: 429 $'
|
12
|
*/
|
13
|
|
14
|
package edu.ucsb.nceas.metacat;
|
15
|
|
16
|
import java.util.Comparator;
|
17
|
|
18
|
/**
|
19
|
* A utility class that sorts two node records.
|
20
|
* <p>
|
21
|
* The order of the records
|
22
|
* determines how the XML document is printed from DocumentImpl.toXml(),
|
23
|
* so it is important that the sort order specified here results in a depth
|
24
|
* first traversal of the nodes in tree. Currently, the nodes are inserted
|
25
|
* into the database in this depth-forst order, so the nodeid identifiers
|
26
|
* are a good indicator of the proper sort order.
|
27
|
* <p>
|
28
|
* However, if we modify data loading semantics to allow document nodes to
|
29
|
* be rearranged, or otherwise change the nodeindex value, this current
|
30
|
* sort algorithm will fail to work.
|
31
|
*/
|
32
|
public class NodeComparator implements Comparator {
|
33
|
|
34
|
static int LESS = -1;
|
35
|
static int EQUALS = 0;
|
36
|
static int GREATER = 1;
|
37
|
|
38
|
/**
|
39
|
* Constructor
|
40
|
*/
|
41
|
public NodeComparator() {
|
42
|
}
|
43
|
|
44
|
/**
|
45
|
* compare two objects to determine proper sort order -- delegates to
|
46
|
* the compare(NodeRecord, NodeRecord) method.
|
47
|
*/
|
48
|
public int compare(Object o1, Object o2) {
|
49
|
return compare((NodeRecord)o1, (NodeRecord)o2);
|
50
|
}
|
51
|
|
52
|
/**
|
53
|
* compare two NodeRecord objects to determine proper sort order. The
|
54
|
* node records are equal if their nodeid fields are equal. One is
|
55
|
* less than another if its parentnodeid is less, or if its parentnodeid
|
56
|
* is equal and its nodeindex is less. One is greater than another if
|
57
|
* its parentnodeid is greater, or if its parentnodeid is equal and
|
58
|
* its nodeindex is greater.
|
59
|
*/
|
60
|
public int compare(NodeRecord o1, NodeRecord o2) {
|
61
|
if (o1.nodeid == o2.nodeid) {
|
62
|
return EQUALS;
|
63
|
} else if (o1.nodeid < o2.nodeid) {
|
64
|
return LESS;
|
65
|
} else if (o1.nodeid > o2.nodeid) {
|
66
|
return GREATER;
|
67
|
|
68
|
/* // This is old code that used to sort the records into breadth-first
|
69
|
// traversal order, based on the parentnodeid and the nodeindex.
|
70
|
//
|
71
|
if (o1.nodeid == o2.nodeid) {
|
72
|
return EQUALS;
|
73
|
} else if (o1.parentnodeid < o2.parentnodeid) {
|
74
|
return LESS;
|
75
|
} else if (o1.parentnodeid > o2.parentnodeid) {
|
76
|
return GREATER;
|
77
|
} else if (o1.parentnodeid == o2.parentnodeid) {
|
78
|
if (o1.nodeindex < o2.nodeindex) {
|
79
|
return LESS;
|
80
|
} else if (o1.nodeindex > o2.nodeindex) {
|
81
|
return GREATER;
|
82
|
} else {
|
83
|
// this should never happen because (parentnodeid,nodeindex) is unique
|
84
|
return EQUALS;
|
85
|
}
|
86
|
*/
|
87
|
} else {
|
88
|
// this should never happen because parentnodeid is always <,>, or =
|
89
|
return EQUALS;
|
90
|
}
|
91
|
}
|
92
|
}
|