/
ImmutableMapKeySet.java
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/
ImmutableMapKeySet.java
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/*
* 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 com.google.common.annotations.J2ktIncompatible;
import java.io.Serializable;
import javax.annotation.CheckForNull;
/**
* {@code keySet()} implementation for {@link ImmutableMap}.
*
* @author Jesse Wilson
* @author Kevin Bourrillion
*/
@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
final class ImmutableMapKeySet<K, V> extends IndexedImmutableSet<K> {
private final ImmutableMap<K, V> map;
ImmutableMapKeySet(ImmutableMap<K, V> map) {
this.map = map;
}
@Override
public int size() {
return map.size();
}
@Override
public UnmodifiableIterator<K> iterator() {
return map.keyIterator();
}
@Override
public boolean contains(@CheckForNull Object object) {
return map.containsKey(object);
}
@Override
K get(int index) {
return map.entrySet().asList().get(index).getKey();
}
@Override
boolean isPartialView() {
return true;
}
@Override
@J2ktIncompatible // serialization
@GwtIncompatible // serialization
Object writeReplace() {
return new KeySetSerializedForm<K>(map);
}
@GwtIncompatible // serialization
@J2ktIncompatible
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;
}
}