1 | // License: GPL. See LICENSE file for details.
|
---|
2 | package org.openstreetmap.josm.tools;
|
---|
3 |
|
---|
4 | import java.util.ArrayList;
|
---|
5 | import java.util.Collection;
|
---|
6 | import java.util.HashMap;
|
---|
7 | import java.util.LinkedHashSet;
|
---|
8 | import java.util.List;
|
---|
9 | import java.util.Map;
|
---|
10 | import java.util.Map.Entry;
|
---|
11 | import java.util.Set;
|
---|
12 |
|
---|
13 | /**
|
---|
14 | * MultiMap - maps keys to multiple values
|
---|
15 | *
|
---|
16 | * Corresponds to Google guava LinkedHashMultimap and Apache Collections MultiValueMap
|
---|
17 | * but it is an independent (simple) implementation.
|
---|
18 | *
|
---|
19 | */
|
---|
20 | public class MultiMap<A, B> {
|
---|
21 |
|
---|
22 | private final Map<A, Set<B>> map;
|
---|
23 |
|
---|
24 | /**
|
---|
25 | * Constructs a new {@code MultiMap}.
|
---|
26 | */
|
---|
27 | public MultiMap() {
|
---|
28 | map = new HashMap<>();
|
---|
29 | }
|
---|
30 |
|
---|
31 | /**
|
---|
32 | * Constructs a new {@code MultiMap} with the specified initial capacity.
|
---|
33 | * @param capacity the initial capacity
|
---|
34 | */
|
---|
35 | public MultiMap(int capacity) {
|
---|
36 | map = new HashMap<>(capacity);
|
---|
37 | }
|
---|
38 |
|
---|
39 | /**
|
---|
40 | * Map a key to a value.
|
---|
41 | *
|
---|
42 | * Can be called multiple times with the same key, but different value.
|
---|
43 | */
|
---|
44 | public void put(A key, B value) {
|
---|
45 | Set<B> vals = map.get(key);
|
---|
46 | if (vals == null) {
|
---|
47 | vals = new LinkedHashSet<>();
|
---|
48 | map.put(key, vals);
|
---|
49 | }
|
---|
50 | vals.add(value);
|
---|
51 | }
|
---|
52 |
|
---|
53 | /**
|
---|
54 | * Put a key that maps to nothing. (Only if it is not already in the map)
|
---|
55 | *
|
---|
56 | * Afterwards containsKey(key) will return true and get(key) will return
|
---|
57 | * an empty Set instead of null.
|
---|
58 | */
|
---|
59 | public void putVoid(A key) {
|
---|
60 | if (map.containsKey(key))
|
---|
61 | return;
|
---|
62 | map.put(key, new LinkedHashSet<B>());
|
---|
63 | }
|
---|
64 |
|
---|
65 | /**
|
---|
66 | * Map the key to all the given values.
|
---|
67 | *
|
---|
68 | * Adds to the mappings that are already there.
|
---|
69 | */
|
---|
70 | public void putAll(A key, Collection<B> values) {
|
---|
71 | Set<B> vals = map.get(key);
|
---|
72 | if (vals == null) {
|
---|
73 | vals = new LinkedHashSet<>(values);
|
---|
74 | map.put(key, vals);
|
---|
75 | }
|
---|
76 | vals.addAll(values);
|
---|
77 | }
|
---|
78 |
|
---|
79 | /**
|
---|
80 | * Get the keySet.
|
---|
81 | */
|
---|
82 | public Set<A> keySet() {
|
---|
83 | return map.keySet();
|
---|
84 | }
|
---|
85 |
|
---|
86 | /**
|
---|
87 | * Returns the Set associated with the given key. Result is null if
|
---|
88 | * nothing has been mapped to this key.
|
---|
89 | *
|
---|
90 | * Modifications of the returned list changes the underling map,
|
---|
91 | * but you should better not do that.
|
---|
92 | */
|
---|
93 | public Set<B> get(A key) {
|
---|
94 | return map.get(key);
|
---|
95 | }
|
---|
96 |
|
---|
97 | /**
|
---|
98 | * Like get, but returns an empty Set if nothing has been mapped to the key.
|
---|
99 | */
|
---|
100 | public Set<B> getValues(A key) {
|
---|
101 | if (!map.containsKey(key))
|
---|
102 | return new LinkedHashSet<>();
|
---|
103 | return map.get(key);
|
---|
104 | }
|
---|
105 |
|
---|
106 | public boolean isEmpty() {
|
---|
107 | return map.isEmpty();
|
---|
108 | }
|
---|
109 |
|
---|
110 | public boolean containsKey(A key) {
|
---|
111 | return map.containsKey(key);
|
---|
112 | }
|
---|
113 |
|
---|
114 | /**
|
---|
115 | * Returns true if the multimap contains a value for a key.
|
---|
116 | *
|
---|
117 | * @param key The key
|
---|
118 | * @param value The value
|
---|
119 | * @return true if the key contains the value
|
---|
120 | */
|
---|
121 | public boolean contains(A key, B value) {
|
---|
122 | Set<B> values = get(key);
|
---|
123 | return (values == null) ? false : values.contains(value);
|
---|
124 | }
|
---|
125 |
|
---|
126 | public void clear() {
|
---|
127 | map.clear();
|
---|
128 | }
|
---|
129 |
|
---|
130 | public Set<Entry<A, Set<B>>> entrySet() {
|
---|
131 | return map.entrySet();
|
---|
132 | }
|
---|
133 |
|
---|
134 | /**
|
---|
135 | * Returns the number of keys.
|
---|
136 | */
|
---|
137 | public int size() {
|
---|
138 | return map.size();
|
---|
139 | }
|
---|
140 |
|
---|
141 | /**
|
---|
142 | * Returns a collection of all value sets.
|
---|
143 | */
|
---|
144 | public Collection<Set<B>> values() {
|
---|
145 | return map.values();
|
---|
146 | }
|
---|
147 |
|
---|
148 | /**
|
---|
149 | * Removes a cerain key=value mapping.
|
---|
150 | *
|
---|
151 | * @return true, if something was removed
|
---|
152 | */
|
---|
153 | public boolean remove(A key, B value) {
|
---|
154 | Set<B> values = get(key);
|
---|
155 | if (values != null) {
|
---|
156 | return values.remove(value);
|
---|
157 | }
|
---|
158 | return false;
|
---|
159 | }
|
---|
160 |
|
---|
161 | /**
|
---|
162 | * Removes all mappings for a certain key.
|
---|
163 | */
|
---|
164 | public Set<B> remove(A key) {
|
---|
165 | return map.remove(key);
|
---|
166 | }
|
---|
167 |
|
---|
168 | @Override
|
---|
169 | public String toString() {
|
---|
170 | List<String> entries = new ArrayList<>(map.size());
|
---|
171 | for (A key : map.keySet()) {
|
---|
172 | entries.add(key + "->{" + Utils.join(",", map.get(key)) + "}");
|
---|
173 | }
|
---|
174 | return "(" + Utils.join(",", entries) + ")";
|
---|
175 | }
|
---|
176 | }
|
---|