1 | // License: GPL. For details, see LICENSE file.
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2 | package org.openstreetmap.josm.tools;
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3 | import java.util.ArrayList;
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4 | import java.util.List;
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5 | import java.util.Objects;
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6 |
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7 | /**
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8 | * A pair of objects.
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9 | * @param <A> Type of first item
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10 | * @param <B> Type of second item
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11 | * @since 429
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12 | */
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13 | public final class Pair<A, B> {
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14 |
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15 | /**
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16 | * The first item
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17 | */
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18 | public A a;
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19 |
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20 | /**
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21 | * The second item
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22 | */
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23 | public B b;
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24 |
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25 | /**
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26 | * Constructs a new {@code Pair}.
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27 | * @param a The first item
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28 | * @param b The second item
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29 | */
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30 | public Pair(A a, B b) {
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31 | this.a = a;
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32 | this.b = b;
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33 | }
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34 |
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35 | @Override
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36 | public int hashCode() {
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37 | return Objects.hash(a, b);
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38 | }
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39 |
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40 | @Override
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41 | public boolean equals(Object other) {
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42 | if (this == other) return true;
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43 | if (other == null || getClass() != other.getClass()) return false;
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44 | Pair<?, ?> pair = (Pair<?, ?>) other;
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45 | return Objects.equals(a, pair.a) &&
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46 | Objects.equals(b, pair.b);
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47 | }
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48 |
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49 | /**
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50 | * Converts a single-typed pair to a list.
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51 | * @param <T> type of both elements
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52 | * @param p pair
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53 | * @return list containing a and b
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54 | */
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55 | public static <T> List<T> toList(Pair<T, T> p) {
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56 | List<T> l = new ArrayList<>(2);
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57 | l.add(p.a);
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58 | l.add(p.b);
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59 | return l;
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60 | }
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61 |
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62 | /**
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63 | * Sorts a single-typed pair so {@code a <= b}.
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64 | * @param <T> type of both elements
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65 | * @param p pair
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66 | * @return {@code p}
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67 | */
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68 | public static <T> Pair<T, T> sort(Pair<T, T> p) {
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69 | if (p.b.hashCode() < p.a.hashCode()) {
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70 | T tmp = p.a;
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71 | p.a = p.b;
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72 | p.b = tmp;
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73 | }
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74 | return p;
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75 | }
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76 |
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77 | @Override
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78 | public String toString() {
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79 | return "<"+a+','+b+'>';
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80 | }
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81 |
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82 | /**
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83 | * Convenient constructor method
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84 | * @param <U> type of first item
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85 | * @param <V> type of second item
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86 | * @param u The first item
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87 | * @param v The second item
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88 | * @return The newly created Pair(u,v)
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89 | */
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90 | public static <U, V> Pair<U, V> create(U u, V v) {
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91 | return new Pair<>(u, v);
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92 | }
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93 | }
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