1 | // License: GPL. For details, see LICENSE file.
|
---|
2 | package org.openstreetmap.josm.gui.mappaint;
|
---|
3 |
|
---|
4 | import java.util.ArrayList;
|
---|
5 | import java.util.List;
|
---|
6 | import java.util.Objects;
|
---|
7 |
|
---|
8 | import org.openstreetmap.josm.gui.mappaint.styleelement.StyleElement;
|
---|
9 | import org.openstreetmap.josm.tools.Pair;
|
---|
10 |
|
---|
11 | /**
|
---|
12 | * Splits the range of possible scale values (0 < scale < +Infinity) into
|
---|
13 | * multiple subranges, for each scale range it keeps a data object of a certain
|
---|
14 | * type T (can be null).
|
---|
15 | *
|
---|
16 | * Used for caching style information for different zoom levels.
|
---|
17 | *
|
---|
18 | * Immutable class, equals & hashCode is required (the same for
|
---|
19 | * {@link StyleElementList}, {@link StyleElement} and its subclasses).
|
---|
20 | *
|
---|
21 | * @param <T> the type of the data objects
|
---|
22 | */
|
---|
23 | public class DividedScale<T> {
|
---|
24 |
|
---|
25 | /**
|
---|
26 | * This exception type is for debugging #8997 and can later be replaced by AssertionError
|
---|
27 | */
|
---|
28 | public static class RangeViolatedError extends RuntimeException {
|
---|
29 | /**
|
---|
30 | * Constructs a new {@code RangeViolatedError}
|
---|
31 | * @param message error message
|
---|
32 | */
|
---|
33 | public RangeViolatedError(String message) {
|
---|
34 | super(message);
|
---|
35 | }
|
---|
36 | }
|
---|
37 |
|
---|
38 | /* list of boundaries for the scale ranges */
|
---|
39 | private final List<Double> bd;
|
---|
40 | /* data objects for each scale range */
|
---|
41 | private final List<T> data;
|
---|
42 |
|
---|
43 | protected DividedScale() {
|
---|
44 | bd = new ArrayList<>();
|
---|
45 | bd.add(0.0);
|
---|
46 | bd.add(Double.POSITIVE_INFINITY);
|
---|
47 | data = new ArrayList<>();
|
---|
48 | data.add(null);
|
---|
49 | }
|
---|
50 |
|
---|
51 | protected DividedScale(DividedScale<T> s) {
|
---|
52 | bd = new ArrayList<>(s.bd);
|
---|
53 | data = new ArrayList<>(s.data);
|
---|
54 | }
|
---|
55 |
|
---|
56 | /**
|
---|
57 | * Looks up the data object for a certain scale value.
|
---|
58 | *
|
---|
59 | * @param scale scale
|
---|
60 | * @return the data object at the given scale, can be null
|
---|
61 | */
|
---|
62 | public T get(double scale) {
|
---|
63 | if (scale <= 0)
|
---|
64 | throw new IllegalArgumentException("scale must be <= 0 but is "+scale);
|
---|
65 | for (int i = 0; i < data.size(); ++i) {
|
---|
66 | if (bd.get(i) < scale && scale <= bd.get(i+1)) {
|
---|
67 | return data.get(i);
|
---|
68 | }
|
---|
69 | }
|
---|
70 | throw new AssertionError();
|
---|
71 | }
|
---|
72 |
|
---|
73 | /**
|
---|
74 | * Looks up the data object for a certain scale value and additionally returns
|
---|
75 | * the scale range where the object is valid.
|
---|
76 | *
|
---|
77 | * @param scale scale
|
---|
78 | * @return pair containing data object and range
|
---|
79 | */
|
---|
80 | public Pair<T, Range> getWithRange(double scale) {
|
---|
81 | if (scale <= 0)
|
---|
82 | throw new IllegalArgumentException("scale must be <= 0 but is "+scale);
|
---|
83 | for (int i = 0; i < data.size(); ++i) {
|
---|
84 | if (bd.get(i) < scale && scale <= bd.get(i+1)) {
|
---|
85 | return new Pair<>(data.get(i), new Range(bd.get(i), bd.get(i+1)));
|
---|
86 | }
|
---|
87 | }
|
---|
88 | throw new AssertionError();
|
---|
89 | }
|
---|
90 |
|
---|
91 | /**
|
---|
92 | * Add data object which is valid for the given range.
|
---|
93 | *
|
---|
94 | * This is only possible, if there is no data for the given range yet.
|
---|
95 | *
|
---|
96 | * @param o data object
|
---|
97 | * @param r the valid range
|
---|
98 | * @return a new, updated, <code>DividedScale</code> object
|
---|
99 | */
|
---|
100 | public DividedScale<T> put(T o, Range r) {
|
---|
101 | DividedScale<T> s = new DividedScale<>(this);
|
---|
102 | s.putImpl(o, r.getLower(), r.getUpper());
|
---|
103 | s.consistencyTest();
|
---|
104 | return s;
|
---|
105 | }
|
---|
106 |
|
---|
107 | /**
|
---|
108 | * Implementation of the <code>put</code> operation.
|
---|
109 | *
|
---|
110 | * ASCII-art explanation:
|
---|
111 | *
|
---|
112 | * data[i]
|
---|
113 | * --|-------|---------|--
|
---|
114 | * bd[i-1] bd[i] bd[i+1]
|
---|
115 | *
|
---|
116 | * (--------]
|
---|
117 | * lower upper
|
---|
118 | * @param o data object
|
---|
119 | * @param lower lower bound
|
---|
120 | * @param upper upper bound
|
---|
121 | */
|
---|
122 | private void putImpl(T o, double lower, double upper) {
|
---|
123 | int i = 0;
|
---|
124 | while (bd.get(i) < lower) {
|
---|
125 | ++i;
|
---|
126 | }
|
---|
127 | if (bd.get(i) == lower) {
|
---|
128 | if (upper > bd.get(i+1))
|
---|
129 | throw new RangeViolatedError("the new range must be within a single subrange (1)");
|
---|
130 | if (data.get(i) != null)
|
---|
131 | throw new RangeViolatedError("the new range must be within a subrange that has no data");
|
---|
132 |
|
---|
133 | if (bd.get(i+1) == upper) {
|
---|
134 | // --|-------|--------|--
|
---|
135 | // i-1 i i+1
|
---|
136 | // (--------]
|
---|
137 | data.set(i, o);
|
---|
138 | } else {
|
---|
139 | // --|-------|--------|--
|
---|
140 | // i-1 i i+1
|
---|
141 | // (-----]
|
---|
142 | bd.add(i+1, upper);
|
---|
143 | data.add(i, o);
|
---|
144 | }
|
---|
145 | } else {
|
---|
146 | if (bd.get(i) < upper)
|
---|
147 | throw new RangeViolatedError("the new range must be within a single subrange (2)");
|
---|
148 | if (data.get(i-1) != null)
|
---|
149 | throw new AssertionError();
|
---|
150 |
|
---|
151 | // --|-------|--------|--
|
---|
152 | // i-1 i i+1
|
---|
153 | // (--] or
|
---|
154 | // (----]
|
---|
155 | bd.add(i, lower);
|
---|
156 | data.add(i, o);
|
---|
157 |
|
---|
158 | // --|--|----|--------|--
|
---|
159 | // i-1 i i+1 i+2
|
---|
160 | // (--]
|
---|
161 | if (bd.get(i+1) > upper) {
|
---|
162 | bd.add(i+1, upper);
|
---|
163 | data.add(i+1, null);
|
---|
164 | }
|
---|
165 | }
|
---|
166 | }
|
---|
167 |
|
---|
168 | /**
|
---|
169 | * Runs a consistency test.
|
---|
170 | * @throws AssertionError When an invariant is broken.
|
---|
171 | */
|
---|
172 | public void consistencyTest() {
|
---|
173 | if (bd.size() < 2) throw new AssertionError(bd);
|
---|
174 | if (data.isEmpty()) throw new AssertionError(data);
|
---|
175 | if (bd.size() != data.size() + 1) throw new AssertionError();
|
---|
176 | if (bd.get(0) != 0) throw new AssertionError();
|
---|
177 | if (bd.get(bd.size() - 1) != Double.POSITIVE_INFINITY) throw new AssertionError();
|
---|
178 | for (int i = 0; i < data.size() - 1; ++i) {
|
---|
179 | if (bd.get(i) >= bd.get(i + 1)) throw new AssertionError();
|
---|
180 | }
|
---|
181 | }
|
---|
182 |
|
---|
183 | @Override
|
---|
184 | public boolean equals(Object obj) {
|
---|
185 | if (this == obj) return true;
|
---|
186 | if (obj == null || getClass() != obj.getClass()) return false;
|
---|
187 | DividedScale<?> that = (DividedScale<?>) obj;
|
---|
188 | return Objects.equals(bd, that.bd) &&
|
---|
189 | Objects.equals(data, that.data);
|
---|
190 | }
|
---|
191 |
|
---|
192 | @Override
|
---|
193 | public int hashCode() {
|
---|
194 | return Objects.hash(bd, data);
|
---|
195 | }
|
---|
196 |
|
---|
197 | @Override
|
---|
198 | public String toString() {
|
---|
199 | return "DS{" + bd + ' ' + data + '}';
|
---|
200 | }
|
---|
201 | }
|
---|