1 /*
2 * Copyright (c) 2003, Henri Yandell
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or
6 * without modification, are permitted provided that the
7 * following conditions are met:
8 *
9 * + Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * + Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * + Neither the name of Genjava-Core nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32 package com.generationjava.collections;
33
34 import java.util.ArrayList;
35 import java.util.Iterator;
36 import java.util.Collections;
37 import java.util.Comparator;
38
39 import com.generationjava.compare.ObjectComparator;
40
41 /***
42 * An Iterator which can be sorted.
43 */
44 public class SortedIterator implements Iterator {
45
46 private ArrayList cache;
47 private Iterator iterator;
48 private boolean started;
49
50 public SortedIterator(Iterator iterator) {
51 this.cache = new ArrayList();
52 int idx = 0;
53 while(iterator.hasNext()) {
54 this.cache.add( new SortIndex(idx, iterator.next()) );
55 idx++;
56 }
57 if(this.iterator == null) {
58 this.iterator = cache.iterator();
59 }
60 }
61
62 /// Start of Iterator
63 public Object next() {
64 this.started = true;
65 return ((SortIndex)this.iterator.next()).getIndexed();
66 }
67
68 public boolean hasNext() {
69 return this.iterator.hasNext();
70 }
71
72 public void remove() {
73 throw new UnsupportedOperationException("Unable to remove once it is sorted. ");
74 }
75 /// End of Iterator
76
77 public void sort(Comparator cmp) {
78 if(this.started) {
79 throw new RuntimeException("Cannot sort as this iterator has been read from. ");
80 }
81 SortComparator srtr = new SortComparator(cmp);
82 Collections.sort(cache, srtr);
83 if(this.iterator == null) {
84 this.iterator = cache.iterator();
85 }
86 }
87
88 public void sort() {
89 sort( new ObjectComparator() );
90 }
91
92
93 }
94
95 class SortIndex {
96
97 private int idx;
98 private Object object;
99
100 public SortIndex(int idx, Object object) {
101 this.idx = idx;
102 this.object = object;
103 }
104
105 public int getIndex() {
106 return this.idx;
107 }
108
109 public Object getIndexed() {
110 return this.object;
111 }
112
113 }
114
115 class SortComparator implements java.util.Comparator {
116
117 private Comparator cmp;
118
119 public SortComparator(Comparator cmp) {
120 this.cmp = cmp;
121 }
122
123 public int compare(Object o1, Object o2) {
124 SortIndex si1 = (SortIndex)o1;
125 SortIndex si2 = (SortIndex)o2;
126 o1 = si1.getIndexed();
127 o2 = si2.getIndexed();
128 return this.cmp.compare(o1,o2);
129 }
130
131 }
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