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1 | /* | |
2 | * Created on Apr 18, 2006 | |
3 | * | |
4 | * Copyright (c) 2006, the JUNG Project and the Regents of the University | |
5 | * of California | |
6 | * All rights reserved. | |
7 | * | |
8 | * This software is open-source under the BSD license; see either | |
9 | * "license.txt" or | |
10 | * http://jung.sourceforge.net/license.txt for a description. | |
11 | */ | |
12 | package edu.uci.ics.jung.utils; | |
13 | ||
14 | import java.util.ArrayList; | |
15 | import java.util.Collection; | |
16 | import java.util.Collections; | |
17 | import java.util.Comparator; | |
18 | import java.util.HashMap; | |
19 | import java.util.Iterator; | |
20 | import java.util.List; | |
21 | import java.util.Map; | |
22 | ||
23 | import org.apache.commons.collections.Predicate; | |
24 | import org.apache.commons.collections.functors.TruePredicate; | |
25 | ||
26 | /** | |
27 | * Generates <code>Iterator</code>s for specified <code>Collection</code>s, | |
28 | * optionally filtered and sorted according to specified parameters. | |
29 | * | |
30 | * @author Joshua O'Madadhain | |
31 | */ | |
32 | 0 | public class IteratorFactory |
33 | { | |
34 | 0 | protected static Map collection_data = new HashMap(); |
35 | ||
36 | public static Iterator getIterator(Collection c) | |
37 | { | |
38 | 0 | IteratorData id = (IteratorData)collection_data.get(c); |
39 | 0 | if (id == null) |
40 | 0 | return c.iterator(); |
41 | ||
42 | 0 | return id.getBackingCollection().iterator(); |
43 | } | |
44 | ||
45 | public static Iterator getIterator(Collection c, Comparator comp, Predicate p) | |
46 | { | |
47 | 0 | IteratorData id = new IteratorData(c, comp, p, true); |
48 | 0 | return id.getBackingCollection().iterator(); |
49 | } | |
50 | ||
51 | public static Iterator getIterator(Collection c, Comparator comp) | |
52 | { | |
53 | 0 | IteratorData id = new IteratorData(c, comp, null, true); |
54 | 0 | return id.getBackingCollection().iterator(); |
55 | } | |
56 | ||
57 | public static Iterator getIterator(Collection c, Predicate p) | |
58 | { | |
59 | 0 | IteratorData id = new IteratorData(c, null, p, true); |
60 | 0 | return id.getBackingCollection().iterator(); |
61 | } | |
62 | ||
63 | public static void addCollection(Collection c, Comparator comp, Predicate p, boolean dynamic) | |
64 | { | |
65 | 0 | IteratorData id = new IteratorData(c, comp, p, dynamic); |
66 | 0 | collection_data.put(c, id); |
67 | 0 | } |
68 | ||
69 | public static void addCollection(Collection c, Comparator comp) | |
70 | { | |
71 | 0 | addCollection(c, comp, null, false); |
72 | 0 | } |
73 | ||
74 | public static void addCollection(Collection c, Predicate p) | |
75 | { | |
76 | 0 | addCollection(c, null, p, false); |
77 | 0 | } |
78 | ||
79 | public static void addCollection(Collection c, Comparator comp, Predicate p) | |
80 | { | |
81 | 0 | addCollection(c, comp, p, false); |
82 | 0 | } |
83 | ||
84 | /** | |
85 | * If <code>dynamic</code> is true, the collection <code>c</code> backing the | |
86 | * <code>Iterator</code> is automatically rebuilt-sorted | |
87 | * and/or re-filtered each time <code>getIterator(c)</code> is called. | |
88 | * (This is done in case either the collection, the comparator, | |
89 | * or the predicate has changed.) | |
90 | * Otherwise, the collection is (re)built only when | |
91 | * <code>buildIterator</code> is called. | |
92 | * | |
93 | * | |
94 | */ | |
95 | public static void setDynamic(boolean dynamic, Collection c) | |
96 | { | |
97 | 0 | IteratorData id = (IteratorData)collection_data.get(c); |
98 | 0 | id.setDynamic(dynamic); |
99 | 0 | } |
100 | ||
101 | public static void setComparator(Collection c, Comparator comp) | |
102 | { | |
103 | 0 | IteratorData id = (IteratorData)collection_data.get(c); |
104 | 0 | id.setComparator(comp); |
105 | 0 | } |
106 | ||
107 | public static void setPredicate(Collection c, Predicate p) | |
108 | { | |
109 | 0 | IteratorData id = (IteratorData)collection_data.get(c); |
110 | 0 | id.setPredicate(p); |
111 | 0 | } |
112 | ||
113 | public static void clear() | |
114 | { | |
115 | 0 | collection_data.clear(); |
116 | 0 | } |
117 | ||
118 | public static void removeCollection(Collection c) | |
119 | { | |
120 | 0 | collection_data.remove(c); |
121 | 0 | } |
122 | ||
123 | 0 | protected static class IteratorData |
124 | { | |
125 | /** | |
126 | * If <code>is_dynamic</code> is true, the collection used to backing the | |
127 | * <code>Iterator</code> is automatically re-sorted | |
128 | * and/or re-filtered each time an <code>Iterator</code> is requested. | |
129 | * (This is done in case either the collection, the comparator, | |
130 | * or the predicate has changed.) | |
131 | * Otherwise, the collection is (re)built only when | |
132 | * <code>buildIterator</code> is called. | |
133 | */ | |
134 | protected boolean is_dynamic; | |
135 | ||
136 | protected Collection collection; | |
137 | protected Comparator comp; | |
138 | protected Collection backing_collection; | |
139 | protected Predicate p; | |
140 | ||
141 | public IteratorData(Collection c, Comparator comp, Predicate p, boolean dynamic) | |
142 | { | |
143 | this.collection = c; | |
144 | this.comp = comp; | |
145 | this.p = p; | |
146 | this.is_dynamic = dynamic; | |
147 | } | |
148 | ||
149 | public void setComparator(Comparator comp) | |
150 | { | |
151 | if (! this.comp.equals(comp)) | |
152 | this.backing_collection = null; | |
153 | this.comp = comp; | |
154 | } | |
155 | ||
156 | public void setPredicate(Predicate p) | |
157 | { | |
158 | if (! this.p.equals(p)) | |
159 | this.backing_collection = null; | |
160 | this.p = p; | |
161 | } | |
162 | ||
163 | public void setDynamic(boolean dynamic) | |
164 | { | |
165 | if (! dynamic) | |
166 | this.backing_collection = null; | |
167 | this.is_dynamic = dynamic; | |
168 | } | |
169 | ||
170 | protected Collection getBackingCollection() | |
171 | { | |
172 | if (is_dynamic) | |
173 | return buildBackingCollection(collection, p, comp); | |
174 | else | |
175 | { | |
176 | if (backing_collection == null) | |
177 | this.backing_collection = buildBackingCollection(collection, p, comp); | |
178 | ||
179 | return backing_collection; | |
180 | } | |
181 | } | |
182 | ||
183 | protected List buildBackingCollection(Collection c, Predicate p, Comparator comp) | |
184 | { | |
185 | List to_iterate = new ArrayList(c.size()); | |
186 | ||
187 | if (p != null && p != TruePredicate.getInstance()) | |
188 | { | |
189 | for (Iterator iter = c.iterator(); iter.hasNext(); ) | |
190 | { | |
191 | Object o = iter.next(); | |
192 | if (p.evaluate(o)) | |
193 | to_iterate.add(o); | |
194 | } | |
195 | } | |
196 | ||
197 | if (comp != null) | |
198 | Collections.sort(to_iterate, comp); | |
199 | ||
200 | return to_iterate; | |
201 | } | |
202 | } | |
203 | } |
this report was generated by version 1.0.5 of jcoverage. |
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