1/*
2 * Copyright (C) 2008 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect;
18
19import static com.google.common.base.Preconditions.checkArgument;
20
21import com.google.common.base.Function;
22import com.google.common.base.Predicate;
23import com.google.common.collect.Maps.EntryTransformer;
24
25import java.io.Serializable;
26import java.util.AbstractSet;
27import java.util.Collection;
28import java.util.Iterator;
29import java.util.Map;
30import java.util.Set;
31import java.util.SortedMap;
32import java.util.SortedSet;
33
34import javax.annotation.Nullable;
35
36/**
37 * Minimal GWT emulation of {@code com.google.common.collect.Platform}.
38 *
39 * <p><strong>This .java file should never be consumed by javac.</strong>
40 *
41 * @author Hayward Chan
42 */
43final class Platform {
44
45  static <T> T[] newArray(T[] reference, int length) {
46    return GwtPlatform.newArray(reference, length);
47  }
48
49  /*
50   * Regarding newSetForMap() and SetFromMap:
51   *
52   * Written by Doug Lea with assistance from members of JCP JSR-166
53   * Expert Group and released to the public domain, as explained at
54   * http://creativecommons.org/licenses/publicdomain
55   */
56
57  static <E> Set<E> newSetFromMap(Map<E, Boolean> map) {
58    return new SetFromMap<E>(map);
59  }
60
61  private static class SetFromMap<E> extends AbstractSet<E>
62      implements Set<E>, Serializable {
63    private final Map<E, Boolean> m; // The backing map
64    private transient Set<E> s; // Its keySet
65
66    SetFromMap(Map<E, Boolean> map) {
67      checkArgument(map.isEmpty(), "Map is non-empty");
68      m = map;
69      s = map.keySet();
70    }
71
72    @Override public void clear() {
73      m.clear();
74    }
75    @Override public int size() {
76      return m.size();
77    }
78    @Override public boolean isEmpty() {
79      return m.isEmpty();
80    }
81    @Override public boolean contains(Object o) {
82      return m.containsKey(o);
83    }
84    @Override public boolean remove(Object o) {
85      return m.remove(o) != null;
86    }
87    @Override public boolean add(E e) {
88      return m.put(e, Boolean.TRUE) == null;
89    }
90    @Override public Iterator<E> iterator() {
91      return s.iterator();
92    }
93    @Override public Object[] toArray() {
94      return s.toArray();
95    }
96    @Override public <T> T[] toArray(T[] a) {
97      return s.toArray(a);
98    }
99    @Override public String toString() {
100      return s.toString();
101    }
102    @Override public int hashCode() {
103      return s.hashCode();
104    }
105    @Override public boolean equals(@Nullable Object object) {
106      return this == object || this.s.equals(object);
107    }
108    @Override public boolean containsAll(Collection<?> c) {
109      return s.containsAll(c);
110    }
111    @Override public boolean removeAll(Collection<?> c) {
112      return s.removeAll(c);
113    }
114    @Override public boolean retainAll(Collection<?> c) {
115      return s.retainAll(c);
116    }
117  }
118
119  static MapMaker tryWeakKeys(MapMaker mapMaker) {
120    return mapMaker;
121  }
122
123  static <K, V1, V2> SortedMap<K, V2> mapsTransformEntriesSortedMap(
124      SortedMap<K, V1> fromMap,
125      EntryTransformer<? super K, ? super V1, V2> transformer) {
126    return Maps.transformEntriesIgnoreNavigable(fromMap, transformer);
127  }
128
129  static <K, V> SortedMap<K, V> mapsAsMapSortedSet(
130      SortedSet<K> set, Function<? super K, V> function) {
131    return Maps.asMapSortedIgnoreNavigable(set, function);
132  }
133
134  static <E> SortedSet<E> setsFilterSortedSet(
135      SortedSet<E> unfiltered, Predicate<? super E> predicate) {
136    return Sets.filterSortedIgnoreNavigable(unfiltered, predicate);
137  }
138
139  static <K, V> SortedMap<K, V> mapsFilterSortedMap(
140      SortedMap<K, V> unfiltered, Predicate<? super Map.Entry<K, V>> predicate) {
141    return Maps.filterSortedIgnoreNavigable(unfiltered, predicate);
142  }
143
144  private Platform() {}
145}
146