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21 package com.db4o.inside.btree;
22
23 import com.db4o.Transaction;
24 import com.db4o.foundation.*;
25 import com.db4o.inside.btree.algebra.*;
26
27
30 public class BTreeRangeSingle implements BTreeRange {
31
32 public static final Comparison4 COMPARISON = new Comparison4() {
33 public int compare(Object  x, Object y) {
34 BTreeRangeSingle xRange = (BTreeRangeSingle)x;
35 BTreeRangeSingle yRange = (BTreeRangeSingle)y;
36 return xRange.first().compareTo(yRange.first());
37 }
38 };
39
40 private final Transaction _transaction;
41
42 private final BTree _btree;
43
44 private final BTreePointer _first;
45
46 private final BTreePointer _end;
47
48 public BTreeRangeSingle(Transaction transaction, BTree btree, BTreePointer first, BTreePointer end) {
49 if (transaction == null || btree == null) {
50 throw new ArgumentNullException();
51 }
52 _transaction = transaction;
53 _btree = btree;
54 _first = first;
55 _end = end;
56 }
57
58 public void accept(BTreeRangeVisitor visitor) {
59 visitor.visit(this);
60 }
61
62 public boolean isEmpty() {
63 return BTreePointer.equals(_first, _end);
64 }
65
66 public int size(){
67 if(isEmpty()){
68 return 0;
69 }
70
71
74
92 int size = 0;
93 final Iterator4 i = keys();
94 while (i.moveNext()) {
95 ++size;
96 }
97 return size;
98 }
99
100 public Iterator4 pointers() {
101 return new BTreeRangePointerIterator(this);
102 }
103
104 public Iterator4 keys() {
105 return new BTreeRangeKeyIterator(this);
106 }
107
108 public final BTreePointer end() {
109 return _end;
110 }
111
112 public Transaction transaction() {
113 return _transaction;
114 }
115
116 public BTreePointer first() {
117 return _first;
118 }
119
120 public BTreeRange greater() {
121 return newBTreeRangeSingle(_end, null);
122 }
123
124 public BTreeRange union(BTreeRange other) {
125 if (null == other) {
126 throw new ArgumentNullException();
127 }
128 return new BTreeRangeSingleUnion(this).dispatch(other);
129 }
130
131 public boolean adjacent(BTreeRangeSingle range) {
132 return BTreePointer.equals(_end, range._first)
133 || BTreePointer.equals(range._end, _first);
134 }
135
136 public boolean overlaps(BTreeRangeSingle range) {
137 return firstOverlaps(this, range) || firstOverlaps(range, this);
138 }
139
140 private boolean firstOverlaps(BTreeRangeSingle x, BTreeRangeSingle y) {
141 return BTreePointer.lessThan(y._first, x._end)
142 && BTreePointer.lessThan(x._first, y._end);
143 }
144
145 public BTreeRange extendToFirst() {
146 return newBTreeRangeSingle(firstBTreePointer(), _end);
147 }
148
149 public BTreeRange extendToLast() {
150 return newBTreeRangeSingle(_first, null);
151 }
152
153 public BTreeRange smaller() {
154 return newBTreeRangeSingle(firstBTreePointer(), _first);
155 }
156
157 public BTreeRangeSingle newBTreeRangeSingle(BTreePointer first, BTreePointer end) {
158 return new BTreeRangeSingle(transaction(), _btree, first, end);
159 }
160
161 public BTreeRange newEmptyRange() {
162 return newBTreeRangeSingle(null, null);
163 }
164
165 private BTreePointer firstBTreePointer() {
166 return btree().firstPointer(transaction());
167 }
168
169 private BTree btree() {
170 return _btree;
171 }
172
173 public BTreeRange intersect(BTreeRange range) {
174 if (null == range) {
175 throw new ArgumentNullException();
176 }
177 return new BTreeRangeSingleIntersect(this).dispatch(range);
178 }
179
180 public BTreeRange extendToLastOf(BTreeRange range) {
181 BTreeRangeSingle rangeImpl = checkRangeArgument(range);
182 return newBTreeRangeSingle(_first, rangeImpl._end);
183 }
184
185 public String toString() {
186 return "BTreeRangeSingle(first=" + _first + ", end=" + _end + ")";
187 }
188
189 private BTreeRangeSingle checkRangeArgument(BTreeRange range) {
190 if (null == range) {
191 throw new ArgumentNullException();
192 }
193 BTreeRangeSingle rangeImpl = (BTreeRangeSingle)range;
194 if (btree() != rangeImpl.btree()) {
195 throw new IllegalArgumentException ();
196 }
197 return rangeImpl;
198 }
199
200 public BTreePointer lastPointer() {
201 if(_end == null){
202 return btree().lastPointer(transaction());
203 }
204 return _end.previous();
205 }
206
207 }
208 |
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