/*
    * Copyright (C) 2008 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.collect;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  import com.google.common.base.Function;
  import com.google.common.base.Predicate;
  import com.google.common.collect.Maps.EntryTransformer;
  
  import java.io.Serializable;
  import java.util.AbstractSet;
  import java.util.Collection;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Set;
  import java.util.SortedMap;
  import java.util.SortedSet;
  
  import javax.annotation.Nullable;
  
  /**
   * Minimal GWT emulation of {@code com.google.common.collect.Platform}.
   *
   * <p><strong>This .java file should never be consumed by javac.</strong>
   *
   * @author Hayward Chan
   */
  final class Platform {
  
    static <T> T[] newArray(T[] reference, int length) {
      return GwtPlatform.newArray(reference, length);
    }
    
    /*
     * Regarding newSetForMap() and SetFromMap:
     *
     * Written by Doug Lea with assistance from members of JCP JSR-166
     * Expert Group and released to the public domain, as explained at
     * http://creativecommons.org/licenses/publicdomain
     */
    
    static <E> Set<E> newSetFromMap(Map<E, Boolean> map) {
      return new SetFromMap<E>(map);
    }
  
    private static class SetFromMap<E> extends AbstractSet<E>
        implements Set<E>, Serializable {
      private final Map<E, Boolean> m; // The backing map
      private transient Set<E> s; // Its keySet
  
      SetFromMap(Map<E, Boolean> map) {
        checkArgument(map.isEmpty(), "Map is non-empty");
        m = map;
        s = map.keySet();
      }
  
      @Override public void clear() {
        m.clear();
      }
      @Override public int size() {
        return m.size();
      }
      @Override public boolean isEmpty() {
        return m.isEmpty();
      }
      @Override public boolean contains(Object o) {
        return m.containsKey(o);
      }
      @Override public boolean remove(Object o) {
        return m.remove(o) != null;
      }
      @Override public boolean add(E e) {
        return m.put(e, Boolean.TRUE) == null;
      }
      @Override public Iterator<E> iterator() {
        return s.iterator();
      }
      @Override public Object[] toArray() {
        return s.toArray();
      }
      @Override public <T> T[] toArray(T[] a) {
        return s.toArray(a);
      }
      @Override public String toString() {
       return s.toString();
     }
     @Override public int hashCode() {
       return s.hashCode();
     }
     @Override public boolean equals(@Nullable Object object) {
       return this == object || this.s.equals(object);
     }
     @Override public boolean containsAll(Collection<?> c) {
       return s.containsAll(c);
     }
     @Override public boolean removeAll(Collection<?> c) {
       return s.removeAll(c);
     }
     @Override public boolean retainAll(Collection<?> c) {
       return s.retainAll(c);
     }
   }
 
   static MapMaker tryWeakKeys(MapMaker mapMaker) {
     return mapMaker;
   }
 
   static <K, V1, V2> SortedMap<K, V2> mapsTransformEntriesSortedMap(
       SortedMap<K, V1> fromMap,
       EntryTransformer<? super K, ? super V1, V2> transformer) {
     return Maps.transformEntriesIgnoreNavigable(fromMap, transformer);
   }
 
   static <K, V> SortedMap<K, V> mapsAsMapSortedSet(
       SortedSet<K> set, Function<? super K, V> function) {
     return Maps.asMapSortedIgnoreNavigable(set, function);
   }
 
   static <E> SortedSet<E> setsFilterSortedSet(
       SortedSet<E> unfiltered, Predicate<? super E> predicate) {
     return Sets.filterSortedIgnoreNavigable(unfiltered, predicate);
   }
   
   static <K, V> SortedMap<K, V> mapsFilterSortedMap(
       SortedMap<K, V> unfiltered, Predicate<? super Map.Entry<K, V>> predicate) {
     return Maps.filterSortedIgnoreNavigable(unfiltered, predicate);
   }
 
   private Platform() {}
 }