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author | Pacien TRAN-GIRARD | 2016-05-10 17:10:31 +0200 |
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committer | Pacien TRAN-GIRARD | 2016-05-10 17:10:31 +0200 |
commit | 766114c05bcd0b0388988aaf606e046857e6946a (patch) | |
tree | 91ccdb1b82664c8e6d4cb5469f18da2ef08fe5e9 | |
parent | e85032012f1d5ded1b6a49a88d345cc60a6ac88b (diff) | |
download | xblast-766114c05bcd0b0388988aaf606e046857e6946a.tar.gz |
Add lists and maps functions
-rw-r--r-- | src/ch/epfl/xblast/Lists.java | 48 | ||||
-rw-r--r-- | test/ch/epfl/xblast/ListsTest.java | 47 |
2 files changed, 91 insertions, 4 deletions
diff --git a/src/ch/epfl/xblast/Lists.java b/src/ch/epfl/xblast/Lists.java index cc6a1c8..bf0cafa 100644 --- a/src/ch/epfl/xblast/Lists.java +++ b/src/ch/epfl/xblast/Lists.java | |||
@@ -2,6 +2,7 @@ package ch.epfl.xblast; | |||
2 | 2 | ||
3 | import java.util.*; | 3 | import java.util.*; |
4 | import java.util.stream.Collectors; | 4 | import java.util.stream.Collectors; |
5 | import java.util.stream.IntStream; | ||
5 | import java.util.stream.Stream; | 6 | import java.util.stream.Stream; |
6 | 7 | ||
7 | /** | 8 | /** |
@@ -181,4 +182,51 @@ public final class Lists { | |||
181 | .collect(Collectors.toList())); | 182 | .collect(Collectors.toList())); |
182 | } | 183 | } |
183 | 184 | ||
185 | /** | ||
186 | * Maps linearly two lists. | ||
187 | * | ||
188 | * @param kl the keys list | ||
189 | * @param vl the values list | ||
190 | * @param <K> the key type | ||
191 | * @param <V> the value type | ||
192 | * @return the map | ||
193 | */ | ||
194 | public static <K, V> Map<K, V> linearMap(List<K> kl, List<V> vl) { | ||
195 | if (Objects.isNull(kl) || Objects.isNull(vl) || kl.size() != vl.size()) | ||
196 | throw new IllegalArgumentException(); | ||
197 | |||
198 | return Collections.unmodifiableMap(IntStream | ||
199 | .range(0, kl.size()).mapToObj(i -> i) | ||
200 | .filter(i -> Objects.nonNull(vl.get(i))) | ||
201 | .collect(Collectors.toMap(kl::get, vl::get))); | ||
202 | } | ||
203 | |||
204 | /** | ||
205 | * Merges two maps Map<K1, IK> and Map<IK, V> -> Map<K1, V>. | ||
206 | * | ||
207 | * @param m1 key maps | ||
208 | * @param m2 values maps | ||
209 | * @param <K> the keys type | ||
210 | * @param <IK> the intermediate keys type | ||
211 | * @param <V> the values type | ||
212 | * @return the traversing map | ||
213 | */ | ||
214 | public static <K, IK, V> Map<K, V> traverseMaps(Map<K, IK> m1, Map<IK, V> m2) { | ||
215 | return Collections.unmodifiableMap(m1.entrySet().stream() | ||
216 | .collect(Collectors.toMap(Map.Entry::getKey, e -> m2.get(e.getValue())))); | ||
217 | } | ||
218 | |||
219 | /** | ||
220 | * Returns an inverted copy of a bijective map. | ||
221 | * | ||
222 | * @param m the map to invert | ||
223 | * @param <K> the keys type | ||
224 | * @param <V> the values type | ||
225 | * @return the inverted map | ||
226 | */ | ||
227 | public static <K, V> Map<K, V> invertMap(Map<V, K> m) { | ||
228 | return Collections.unmodifiableMap(m.entrySet().stream() | ||
229 | .collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey))); | ||
230 | } | ||
231 | |||
184 | } | 232 | } |
diff --git a/test/ch/epfl/xblast/ListsTest.java b/test/ch/epfl/xblast/ListsTest.java index b18b05e..e62eede 100644 --- a/test/ch/epfl/xblast/ListsTest.java +++ b/test/ch/epfl/xblast/ListsTest.java | |||
@@ -2,10 +2,7 @@ package ch.epfl.xblast; | |||
2 | 2 | ||
3 | import org.junit.Test; | 3 | import org.junit.Test; |
4 | 4 | ||
5 | import java.util.ArrayList; | 5 | import java.util.*; |
6 | import java.util.Arrays; | ||
7 | import java.util.LinkedList; | ||
8 | import java.util.List; | ||
9 | import java.util.stream.Collectors; | 6 | import java.util.stream.Collectors; |
10 | import java.util.stream.IntStream; | 7 | import java.util.stream.IntStream; |
11 | 8 | ||
@@ -63,4 +60,46 @@ public class ListsTest { | |||
63 | assertEquals(expected, Lists.permutations(sampleList)); | 60 | assertEquals(expected, Lists.permutations(sampleList)); |
64 | } | 61 | } |
65 | 62 | ||
63 | @Test | ||
64 | public void areListsMapped() { | ||
65 | final List<Character> keyList = Arrays.asList('a', 'b'); | ||
66 | final List<Integer> valueList = Arrays.asList(0, 1); | ||
67 | |||
68 | final Map<Character, Integer> expectedMap = new HashMap<>(); | ||
69 | expectedMap.put('a', 0); | ||
70 | expectedMap.put('b', 1); | ||
71 | |||
72 | assertEquals(expectedMap, Lists.linearMap(keyList, valueList)); | ||
73 | } | ||
74 | |||
75 | @Test | ||
76 | public void areMapsTraversed() { | ||
77 | final Map<Character, Integer> m1 = new HashMap<>(); | ||
78 | m1.put('a', 0); | ||
79 | m1.put('b', 1); | ||
80 | |||
81 | final Map<Integer, String> m2 = new HashMap<>(); | ||
82 | m2.put(0, "Apple"); | ||
83 | m2.put(1, "Banana"); | ||
84 | |||
85 | final Map<Character, String> expectedMap = new HashMap<>(); | ||
86 | expectedMap.put('a', "Apple"); | ||
87 | expectedMap.put('b', "Banana"); | ||
88 | |||
89 | assertEquals(expectedMap, Lists.traverseMaps(m1, m2)); | ||
90 | } | ||
91 | |||
92 | @Test | ||
93 | public void isMapInverted() { | ||
94 | final Map<Character, Integer> sampleMap = new HashMap<>(); | ||
95 | sampleMap.put('a', 0); | ||
96 | sampleMap.put('b', 1); | ||
97 | |||
98 | final Map<Integer, Character> expectedMap = new HashMap<>(); | ||
99 | expectedMap.put(0, 'a'); | ||
100 | expectedMap.put(1, 'b'); | ||
101 | |||
102 | assertEquals(expectedMap, Lists.invertMap(sampleMap)); | ||
103 | } | ||
104 | |||
66 | } | 105 | } |