/*
* 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 com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.io.Serializable;
import java.util.Map.Entry;
import javax.annotation.Nullable;
/**
* {@code keySet()} implementation for {@link ImmutableMap}.
*
* @author Jesse Wilson
* @author Kevin Bourrillion
*/
@GwtCompatible(emulated = true)
abstract class ImmutableMapKeySet<K, V> extends TransformedImmutableSet<Entry<K, V>, K> {
ImmutableMapKeySet(ImmutableSet<Entry<K, V>> entrySet) {
super(entrySet);
}
ImmutableMapKeySet(ImmutableSet<Entry<K, V>> entrySet, int hashCode) {
super(entrySet, hashCode);
}
abstract ImmutableMap<K, V> map();
@Override
K transform(Entry<K, V> entry) {
return entry.getKey();
}
@Override
public boolean contains(@Nullable Object object) {
return map().containsKey(object);
}
@Override
boolean isPartialView() {
return true;
}
@Override
ImmutableList<K> createAsList() {
final ImmutableList<Entry<K, V>> entryList = map().entrySet().asList();
return new ImmutableAsList<K>() {
@Override
public K get(int index) {
return entryList.get(index).getKey();
}
@Override
ImmutableCollection<K> delegateCollection() {
return ImmutableMapKeySet.this;
}
};
}
@GwtIncompatible("serialization")
@Override Object writeReplace() {
return new KeySetSerializedForm<K>(map());
}
@GwtIncompatible("serialization")
private static class KeySetSerializedForm<K> implements Serializable {
final ImmutableMap<K, ?> map;
KeySetSerializedForm(ImmutableMap<K, ?> map) {
this.map = map;
}
Object readResolve() {
return map.keySet();
}
private static final long serialVersionUID = 0;
}
}